Sample records for uncemented hip prosthesis

  1. 21 CFR 888.3390 - Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint femoral (hemi-hip) metal/polymer... § 888.3390 Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis is a two-part...

  2. 21 CFR 888.3310 - Hip joint metal/polymer constrained cemented or uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint metal/polymer constrained cemented or... Hip joint metal/polymer constrained cemented or uncemented prosthesis. (a) Identification. A hip joint metal/polymer constrained cemented or uncemented prosthesis is a device intended to be implanted to...

  3. 21 CFR 888.3310 - Hip joint metal/polymer constrained cemented or uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/polymer constrained cemented or... Hip joint metal/polymer constrained cemented or uncemented prosthesis. (a) Identification. A hip joint metal/polymer constrained cemented or uncemented prosthesis is a device intended to be implanted to...

  4. 21 CFR 888.3310 - Hip joint metal/polymer constrained cemented or uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hip joint metal/polymer constrained cemented or... Hip joint metal/polymer constrained cemented or uncemented prosthesis. (a) Identification. A hip joint metal/polymer constrained cemented or uncemented prosthesis is a device intended to be implanted to...

  5. 21 CFR 888.3310 - Hip joint metal/polymer constrained cemented or uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hip joint metal/polymer constrained cemented or... Hip joint metal/polymer constrained cemented or uncemented prosthesis. (a) Identification. A hip joint metal/polymer constrained cemented or uncemented prosthesis is a device intended to be implanted to...

  6. 21 CFR 888.3310 - Hip joint metal/polymer constrained cemented or uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hip joint metal/polymer constrained cemented or... Hip joint metal/polymer constrained cemented or uncemented prosthesis. (a) Identification. A hip joint metal/polymer constrained cemented or uncemented prosthesis is a device intended to be implanted to...

  7. 21 CFR 888.3300 - Hip joint metal constrained cemented or uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint metal constrained cemented or uncemented... metal constrained cemented or uncemented prosthesis. (a) Identification. A hip joint metal constrained... Administration on or before December 26, 1996 for any hip joint metal constrained cemented or uncemented...

  8. 21 CFR 888.3358 - Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/polymer/metal semi-constrained... Devices § 888.3358 Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis. (a) Identification. A hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis is a device...

  9. 21 CFR 888.3300 - Hip joint metal constrained cemented or uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal constrained cemented or uncemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3300 Hip joint metal constrained cemented or uncemented prosthesis. (a) Identification. A hip joint metal constrained...

  10. 21 CFR 888.3390 - Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis. 888.3390 Section 888.3390 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices...

  11. 21 CFR 888.3300 - Hip joint metal constrained cemented or uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hip joint metal constrained cemented or uncemented prosthesis. 888.3300 Section 888.3300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3300 Hip joint...

  12. 21 CFR 888.3300 - Hip joint metal constrained cemented or uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hip joint metal constrained cemented or uncemented prosthesis. 888.3300 Section 888.3300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3300 Hip joint...

  13. 21 CFR 888.3300 - Hip joint metal constrained cemented or uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hip joint metal constrained cemented or uncemented prosthesis. 888.3300 Section 888.3300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3300 Hip joint...

  14. Mortality rates at 10 years after metal-on-metal hip resurfacing compared with total hip replacement in England: retrospective cohort analysis of hospital episode statistics

    PubMed Central

    Kendal, Adrian R; Prieto-Alhambra, Daniel; Arden, Nigel K; Judge, Andrew

    2013-01-01

    Objectives To compare 10 year mortality rates among patients undergoing metal-on-metal hip resurfacing and total hip replacement in England. Design Retrospective cohort study. Setting English hospital episode statistics database linked to mortality records from the Office for National Statistics. Population All adults who underwent primary elective hip replacement for osteoarthritis from April 1999 to March 2012. The exposure of interest was prosthesis type: cemented total hip replacement, uncemented total hip replacement, and metal-on-metal hip resurfacing. Confounding variables included age, sex, Charlson comorbidity index, rurality, area deprivation, surgical volume, and year of operation. Main outcome measures All cause mortality. Propensity score matching was used to minimise confounding by indication. Kaplan-Meier plots estimated the probability of survival up to 10 years after surgery. Multilevel Cox regression modelling, stratified on matched sets, described the association between prosthesis type and time to death, accounting for variation across hospital trusts. Results 7437 patients undergoing metal-on-metal hip resurfacing were matched to 22 311 undergoing cemented total hip replacement; 8101 patients undergoing metal-on-metal hip resurfacing were matched to 24 303 undergoing uncemented total hip replacement. 10 year rates of cumulative mortality were 271 (3.6%) for metal-on-metal hip resurfacing versus 1363 (6.1%) for cemented total hip replacement, and 239 (3.0%) for metal-on-metal hip resurfacing versus 999 (4.1%) for uncemented total hip replacement. Patients undergoing metal-on-metal hip resurfacing had an increased survival probability (hazard ratio 0.51 (95% confidence interval 0.45 to 0.59) for cemented hip replacement; 0.55 (0.47 to 0.65) for uncemented hip replacement). There was no evidence for an interaction with age or sex. Conclusions Patients with hip osteoarthritis undergoing metal-on-metal hip resurfacing have reduced mortality in the long term compared with those undergoing cemented or uncemented total hip replacement. This difference persisted after extensive adjustment for confounding factors available in our data. The study results can be applied to matched populations, which exclude patients who are very old and have had complex total hip replacements. Although residual confounding is possible, the observed effect size is large. These findings require validation in external cohorts and randomised clinical trials. PMID:24284336

  15. 21 CFR 888.3390 - Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... includes prostheses that have a femoral component made of alloys, such as cobalt-chromium-molybdenum, and a snap-fit acetabular component made of an alloy, such as cobalt-chromium-molybdenum, and ultra-high...

  16. 21 CFR 888.3390 - Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... includes prostheses that have a femoral component made of alloys, such as cobalt-chromium-molybdenum, and a snap-fit acetabular component made of an alloy, such as cobalt-chromium-molybdenum, and ultra-high...

  17. 21 CFR 888.3390 - Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... includes prostheses that have a femoral component made of alloys, such as cobalt-chromium-molybdenum, and a snap-fit acetabular component made of an alloy, such as cobalt-chromium-molybdenum, and ultra-high...

  18. Perioperative mortality in hip fracture patients treated with cemented and uncemented hemiprosthesis: a register study of 11,210 patients.

    PubMed

    Talsnes, Ove; Vinje, Tarjei; Gjertsen, Jan Erik; Dahl, Ola E; Engesæter, Lars B; Baste, Valborg; Pripp, Are Hugo; Reikerås, Olav

    2013-06-01

    Adverse events associated with the use of bone cement for fixation of prostheses is a known complication. Due to inconclusive results in studies of hip fracture patients treated with cemented and uncemented hemiprostheses, this study was initiated. Our study is based on data reported to the Norwegian Hip Fracture Register on 11,210 cervical hip fractures treated with hemiprostheses (8,674 cemented and 2,536 uncemented). Significantly increased mortality within the first day of surgery was found in the cemented group (relative risk 2.9, 95 % confidence interval 1.6-5.1, p=0.001). The finding was robust giving the same results after adjusting for independent risk factors such as age, sex, cognitive impairment and comorbidity [American Society of Anesthesiologists (ASA) score]. For the first post-operative day the number needed to harm was 116 (one death for every 116 cemented prosthesis). However, in the most comorbid group (ASA worse than 3), the number needed to harm was only 33. We found increased mortality for the cemented hemiprosthesis the first post-operative day compared to uncemented procedures. This increased risk is closely related to patient comorbidity estimated by the patient's ASA score.

  19. 21 CFR 888.3360 - Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... designs which are intended to be fixed to the bone with bone cement (§ 888.3027) as well as designs which have large window-like holes in the stem of the device and which are intended for use without bone cement. However, in these latter designs, fixation of the device is not achieved by means of bone...

  20. 21 CFR 888.3360 - Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... designs which are intended to be fixed to the bone with bone cement (§ 888.3027) as well as designs which have large window-like holes in the stem of the device and which are intended for use without bone cement. However, in these latter designs, fixation of the device is not achieved by means of bone...

  1. 21 CFR 888.3360 - Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... designs which are intended to be fixed to the bone with bone cement (§ 888.3027) as well as designs which have large window-like holes in the stem of the device and which are intended for use without bone cement. However, in these latter designs, fixation of the device is not achieved by means of bone...

  2. 21 CFR 888.3360 - Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... designs which are intended to be fixed to the bone with bone cement (§ 888.3027) as well as designs which have large window-like holes in the stem of the device and which are intended for use without bone cement. However, in these latter designs, fixation of the device is not achieved by means of bone...

  3. 21 CFR 888.3360 - Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... designs which are intended to be fixed to the bone with bone cement (§ 888.3027) as well as designs which have large window-like holes in the stem of the device and which are intended for use without bone cement. However, in these latter designs, fixation of the device is not achieved by means of bone...

  4. Corail uncemented hemiarthroplasty with a Cathcart head for intracapsular hip fractures.

    PubMed

    Kendrick, B J L; Wilson, H A; Lippett, J E; McAndrew, A R; Andrade, A J M D

    2013-11-01

    The National Institute for Health and Clinical Excellence (NICE) guidelines from 2011 recommend the use of cemented hemi-arthroplasty for appropriate patients with an intracapsular hip fracture. In our institution all patients who were admitted with an intracapsular hip fracture and were suitable for a hemi-arthroplasty between April 2010 and July 2012 received an uncemented prosthesis according to our established departmental routine practice. A retrospective analysis of outcome was performed to establish whether the continued use of an uncemented stem was justified. Patient, surgical and outcome data were collected on the National Hip Fracture database. A total of 306 patients received a Cathcart modular head on a Corail uncemented stem as a hemi-arthroplasty. The mean age of the patients was 83.3 years (SD 7.56; 46.6 to 94) and 216 (70.6%) were women. The mortality rate at 30 days was 5.8%. A total of 46.5% of patients returned to their own home by 30 days, which increased to 73.2% by 120 days. The implant used as a hemi-arthroplasty for intracapsular hip fracture provided satisfactory results, with a good rate of return to pre-injury place of residence and an acceptable mortality rate. Surgery should be performed by those who are familiar with the design of the stem and understand what is required for successful implantation.

  5. 21 CFR 888.3353 - Hip joint metal/ceramic/polymer semi-constrained cemented or nonporous uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... fixed in the intramedullary canal of the femur by impaction with or without use of bone cement. The... nonporous metal alloys, and used with or without bone cement. (b) Classification. Class II. [54 FR 48239...

  6. 21 CFR 888.3353 - Hip joint metal/ceramic/polymer semi-constrained cemented or nonporous uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... fixed in the intramedullary canal of the femur by impaction with or without use of bone cement. The... nonporous metal alloys, and used with or without bone cement. (b) Classification. Class II. [54 FR 48239...

  7. 21 CFR 888.3353 - Hip joint metal/ceramic/polymer semi-constrained cemented or nonporous uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... fixed in the intramedullary canal of the femur by impaction with or without use of bone cement. The... nonporous metal alloys, and used with or without bone cement. (b) Classification. Class II. [54 FR 48239...

  8. 21 CFR 888.3353 - Hip joint metal/ceramic/polymer semi-constrained cemented or nonporous uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... fixed in the intramedullary canal of the femur by impaction with or without use of bone cement. The... nonporous metal alloys, and used with or without bone cement. (b) Classification. Class II. [54 FR 48239...

  9. 21 CFR 888.3353 - Hip joint metal/ceramic/polymer semi-constrained cemented or nonporous uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... fixed in the intramedullary canal of the femur by impaction with or without use of bone cement. The... nonporous metal alloys, and used with or without bone cement. (b) Classification. Class II. [54 FR 48239...

  10. 21 CFR 888.3330 - Hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... component is intended to be fixed with bone cement. The acetabular component is intended for use without bone cement (§ 888.3027). (b) Classification. Class III. (c) Date PMA or notice of completion of a PDP...

  11. 21 CFR 888.3330 - Hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... component is intended to be fixed with bone cement. The acetabular component is intended for use without bone cement (§ 888.3027). (b) Classification. Class III. (c) Date PMA or notice of completion of a PDP...

  12. 21 CFR 888.3330 - Hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... component is intended to be fixed with bone cement. The acetabular component is intended for use without bone cement (§ 888.3027). (b) Classification. Class III. (c) Date PMA or notice of completion of a PDP...

  13. 21 CFR 888.3330 - Hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... component is intended to be fixed with bone cement. The acetabular component is intended for use without bone cement (§ 888.3027). (b) Classification. Class III. (c) Date PMA or notice of completion of a PDP...

  14. 21 CFR 888.3330 - Hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... component is intended to be fixed with bone cement. The acetabular component is intended for use without bone cement (§ 888.3027). (b) Classification. Class III. (c) Date PMA or notice of completion of a PDP...

  15. 21 CFR 888.3200 - Finger joint metal/metal constrained uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Finger joint metal/metal constrained uncemented... metal/metal constrained uncemented prosthesis. (a) Identification. A finger joint metal/metal... Administration on or before December 26, 1996 for any finger joint metal/metal constrained uncemented prosthesis...

  16. 21 CFR 888.3200 - Finger joint metal/metal constrained uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Finger joint metal/metal constrained uncemented... metal/metal constrained uncemented prosthesis. (a) Identification. A finger joint metal/metal... Administration on or before December 26, 1996 for any finger joint metal/metal constrained uncemented prosthesis...

  17. 21 CFR 888.3565 - Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint patellofemorotibial metal/polymer... Devices § 888.3565 Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis is a device...

  18. 21 CFR 888.3690 - Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Shoulder joint humeral (hemi-shoulder) metallic... Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis. (a) Identification. A shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis is a device made of alloys, such as cobalt-chromium...

  19. 21 CFR 888.3690 - Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Shoulder joint humeral (hemi-shoulder) metallic... Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis. (a) Identification. A shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis is a device made of alloys, such as cobalt-chromium...

  20. 21 CFR 888.3690 - Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Shoulder joint humeral (hemi-shoulder) metallic... Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis. (a) Identification. A shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis is a device made of alloys, such as cobalt-chromium...

  1. 21 CFR 888.3690 - Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Shoulder joint humeral (hemi-shoulder) metallic... Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis. (a) Identification. A shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis is a device made of alloys, such as cobalt-chromium...

  2. 21 CFR 888.3690 - Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Shoulder joint humeral (hemi-shoulder) metallic... Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis. (a) Identification. A shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis is a device made of alloys, such as cobalt-chromium...

  3. 21 CFR 888.3565 - Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint patellofemorotibial metal/polymer... Devices § 888.3565 Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis is a device...

  4. 21 CFR 888.3565 - Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint patellofemorotibial metal/polymer... Devices § 888.3565 Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis is a device...

  5. 21 CFR 888.3565 - Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint patellofemorotibial metal/polymer... Devices § 888.3565 Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis is a device...

  6. [Total hip replacement with isoelastic prosthesis in animals (author's transl)].

    PubMed

    Muhr, O; Stockhusen, H; Müller, O

    1976-10-08

    Uncemented fixation and low-fraction materials are the basis of this experiment. Plastics with an elasticity similar to the bone ("isoelasticity") show very propitious material qualities. The direct cementless incorporation of test bodies must be checked. In 63 sheep isoelastic total hip joints were implanted. After 2 till 51 weeks the animals were sacrificed and 44 specimen of hips and organs were explored macroscopically, radiologically, spherimetrically and histologically. The result was: 1. Plastic hip prosthesis are incorporated in the bone, but the boundary layer is built by a collagenous fiber tissue. 2. Loosening brings resoption of the bone and expansion of the structural changed soft tissue. 3. The transformation of the femoral cortex to osteoporosis is considered possibly as the consequence of an insufficient biological transfer of the weight. 4. Fractures of the femoral prosthesis-stem could not be observed. 5. The radiology allows at the pelvis prosthesis a concret statement concerning stability, on the femoral part a probable one. 6. The abrasion is minimal, the tissue reaction to abrasion products is unessential. 7. Small abrasion particles are carried of by the lymph tract and stored in the first regional gland. A more distant spreading is not demonstrable.

  7. 21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing... Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis is a device intended to be implanted...

  8. 21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint patellar (hemi-knee) metallic... § 888.3580 Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis is a device made of...

  9. [Ceramic-ceramic articulation in uncemented total hip arthroplasty].

    PubMed

    Synder, Marek; Drobniewski, Marek; Kozłowski, Piotr; Grzegorzewski, Andrzej

    2005-01-01

    The main problem in total hip arthroplasty (THA) surgery is aseptic loosening of prosthesis components. In most cases the phagocytes reaction against the wear particle during the hip movement is responsible for aseptic prosthesis loosening. To prevent this reaction different hip articulation are invented to reduce this reaction. One of these solutions is ceramic-ceramic hip prosthesis articulation. The aim of this study was to evaluate the long-term results in patients who were treated because of coxarthrosis by means of ceramic-ceramic hip prosthesis. We analyzed 258 primary THA (222 patients, 116 women and 106 men) who were treated because of advanced coxarthrosis by Mittelmeier type hip endoprosthesis (ceramic-ceramic articulation). The mean age of patients at the surgery was 45.6 years and a mean follow-up 10.2 years. In most of our cases the idiopathic, traumatic and dysplastic coxarthrosis was noted. For clinical evaluation the classification system proposed by Merle d'Aubigne and Postel with Charnley modification was used. For radiological evaluation of the steam implantation the classification system proposed by De Lee and Charnley was used and for the cup implantation the system by Gruen and Moreland. In 87 patients (33.7%) the final results was graded as very good, in 96 (37.2%) as good, in 47 (18.2%) as satisfactory and in 28 patients (10.9%) the final results was poor. In analyzed group in 13 patients (5.0%) the revision surgery was necessary. The long-term results of THA with the use of Mittelmeier type of hip prosthesis presented a very low percentage of aseptic loosening. This type of prosthesis gives very high patients satisfaction.

  10. Relationship between biometric characteristics and stem size of uncemented hip prostheses.

    PubMed

    De Clerico, Manuela; Bordini, Barbara; Stea, Susanna; Viceconti, Marco; Toni, Aldo

    2007-06-01

    The authors examined 2329 uncemented hip prosthesis stems (AncaFit stem, Wright Medical Technology, Arlington, TN, USA) implanted between 1996 and 2004 due to primary coxarthrosis. This is the most commonly used stem in the Emilia-Romagna region, in northern Italy, according to data from the Register of Orthopaedic Prosthetic Implants (RIPO). It is produced in eight sizes for each side. We analyzed the relationship between stem size and anthropometric data. Among the patients, 49.5% were men and 50.5% were women; mean age at surgery was 64.1 years (SD 9.1); mean height was 167 cm (SD 8.4), and mean weight was 75.7 kg (SD 12.7). Multifactorial analysis demonstrated that stem size was influenced by sex, age, and height, but not by weight. Besides this, there was an interaction between sex and age: in women, but not in men, the stem size increased with aging.

  11. 21 CFR 888.3570 - Knee joint femoral (hemi-knee) metallic uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint femoral (hemi-knee) metallic uncemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3570 Knee joint femoral (hemi-knee) metallic uncemented prosthesis. (a) Identification. A knee joint femoral (hemi-knee...

  12. 21 CFR 888.3358 - Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... substrates, beads of the same alloy, and in the case of Ti-6Al-4V substrates, fibers of commercially pure titanium or Ti-6Al-4V alloy. The porous coating has a volume porosity between 30 and 70 percent, an average... titanium-aluminum-vanadium (Ti-6Al-4V) alloy and an acetabular component composed of an ultra-high...

  13. 21 CFR 888.3358 - Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... substrates, beads of the same alloy, and in the case of Ti-6Al-4V substrates, fibers of commercially pure titanium or Ti-6Al-4V alloy. The porous coating has a volume porosity between 30 and 70 percent, an average... titanium-aluminum-vanadium (Ti-6Al-4V) alloy and an acetabular component composed of an ultra-high...

  14. 21 CFR 888.3358 - Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... substrates, beads of the same alloy, and in the case of Ti-6Al-4V substrates, fibers of commercially pure titanium or Ti-6Al-4V alloy. The porous coating has a volume porosity between 30 and 70 percent, an average... titanium-aluminum-vanadium (Ti-6Al-4V) alloy and an acetabular component composed of an ultra-high...

  15. 21 CFR 888.3358 - Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... substrates, beads of the same alloy, and in the case of Ti-6Al-4V substrates, fibers of commercially pure titanium or Ti-6Al-4V alloy. The porous coating has a volume porosity between 30 and 70 percent, an average... titanium-aluminum-vanadium (Ti-6Al-4V) alloy and an acetabular component composed of an ultra-high...

  16. Improvements in survival of the uncemented Nottingham Total Shoulder prosthesis: a prospective comparative study

    PubMed Central

    Rosenberg, Nahum; Neumann, Lars; Modi, Amit; Mersich, Istvan J; Wallace, Angus W

    2007-01-01

    Background The uncemented Nottingham Total Shoulder Replacement prosthesis system (Nottingham TSR) was developed from the previous BioModular® shoulder prosthesis taking into consideration the causes of the initial implant's failure. We investigated the impact of changes in the design of Nottingham TSR prosthesis on its survivorship rate. Methods Survivorship analyses of three types of uncemented total shoulder arthroplasty prostheses (BioModular®, initial Nottingham TSR and current Nottingham TSR systems with 11, 8 and 4 year survivorship data respectively) were compared. All these prostheses were implanted for the treatment of disabling pain in the shoulder due to primary and secondary osteoarthritis or rheumatoid arthritis. Each type of the prosthesis studied was implanted in consecutive group of patients – 90 patients with BioModular® system, 103 with the initial Nottingham TSR and 34 patients with the current Nottingham TSR system. The comparison of the annual cumulative survivorship values in the compatible time range between the three groups was done according to the paired t test. Results The 8-year and 11-year survivorship rates for the initially used modified BioModular® uncemented prosthesis were relatively low (75.6% and 71.7% respectively) comparing to the reported survivorship of the conventional cemented implants. The 8-year survivorship for the uncemented Nottingham TSR prosthesis was significantly higher (81.8%), but still not in the desired range of above 90%, that is found in other cemented designs. Glenoid component loosening was the main factor of prosthesis failure in both prostheses and mainly occurred in the first 4 postoperative years. The 4-year survivorship of the currently re-designed Nottingham TSR prosthesis, with hydroxylapatite coating of the glenoid baseplate, was significantly higher, 93.1% as compared to 85.1% of the previous Nottingham TSR. Conclusion The initial Nottingham shoulder prosthesis showed significantly higher survivorship than the BioModular® uncemented prosthesis, but lower than expected. Subsequently re-designed Nottingham TSR system presented a high short term survivorship rate that encourages its ongoing use PMID:17683577

  17. Evaluation of the results from proximal fixation of uncemented conical femoral components in Dorr type C femurs☆☆☆

    PubMed Central

    Ahmad Hatem, Munif; Ferreira da Luz, Bernardo; Nishimoto Nishi, Rodrigo; Gilberto Cimbalista de Alencar, Paulo

    2014-01-01

    Objective To evaluate the results from proximal fixation of uncemented conical femoral components in patients with a type C proximal femur and compare them with the results obtained from type A and B femurs. Methods This was a retrospective study on 87 patients with 90 uncemented total hip arthroplasty procedures. Three patients (three hips) were excluded because their follow-up lasted for less than two years. The follow-up ranged from 2 to 4.3 years and the mean was 2.8 years. The Bicontact femoral implant model was used. The preoperative radiographs were evaluated, the femurs were classified as Dorr types A, B or C and the cortical indices were measured. The patients were evaluated clinically by means of the Harris Hip Score (HHS), before the surgery and at the last follow-up. The sequences of postoperative radiographs were compared regarding stability, complications and any signs of osseointegration of the femoral prosthesis. Results Among the 87 hips with follow-up greater than two years, 32 femurs were type A (37%), 37 type B (42%) and 18 type C (21%). Before the operation, the mean HHS was 39.4 for types A and B and 38.8 for type C. At the last follow-up, the mean HHS was 89.8 for types A and B and 86 for type C. None of the 87 femoral components had been revised by the time of the last follow-up; all of them were considered stable. In 86 cases, the radiographs showed signs of osseointegration. Conclusion There were no significant differences in the clinical results or in the fixation (and osseointegration) of conical uncemented femoral prostheses with proximal porosity, among femurs with different types of femoral morphology according to the Dorr classification. This conclusion may vary if another implant model were to be used. PMID:26229810

  18. 21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. 888.3590 Section 888.3590 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3590...

  19. 21 CFR 888.3180 - Elbow joint humeral (hemi-elbow) metallic uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Elbow joint humeral (hemi-elbow) metallic uncemented prosthesis. 888.3180 Section 888.3180 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3180...

  20. 21 CFR 888.3570 - Knee joint femoral (hemi-knee) metallic uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint femoral (hemi-knee) metallic uncemented prosthesis. 888.3570 Section 888.3570 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3570 Knee joint...

  1. 21 CFR 888.3180 - Elbow joint humeral (hemi-elbow) metallic uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Elbow joint humeral (hemi-elbow) metallic uncemented prosthesis. 888.3180 Section 888.3180 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3180...

  2. 21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. 888.3590 Section 888.3590 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3590...

  3. 21 CFR 888.3180 - Elbow joint humeral (hemi-elbow) metallic uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Elbow joint humeral (hemi-elbow) metallic uncemented prosthesis. 888.3180 Section 888.3180 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3180...

  4. 21 CFR 888.3570 - Knee joint femoral (hemi-knee) metallic uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint femoral (hemi-knee) metallic uncemented prosthesis. 888.3570 Section 888.3570 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3570 Knee joint...

  5. 21 CFR 888.3200 - Finger joint metal/metal constrained uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Finger joint metal/metal constrained uncemented prosthesis. 888.3200 Section 888.3200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3200 Finger joint...

  6. 21 CFR 888.3570 - Knee joint femoral (hemi-knee) metallic uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint femoral (hemi-knee) metallic uncemented prosthesis. 888.3570 Section 888.3570 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3570 Knee joint...

  7. 21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. 888.3590 Section 888.3590 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3590...

  8. 21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. 888.3590 Section 888.3590 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3590...

  9. 21 CFR 888.3570 - Knee joint femoral (hemi-knee) metallic uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint femoral (hemi-knee) metallic uncemented prosthesis. 888.3570 Section 888.3570 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3570 Knee joint...

  10. 21 CFR 888.3200 - Finger joint metal/metal constrained uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Finger joint metal/metal constrained uncemented prosthesis. 888.3200 Section 888.3200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3200 Finger joint...

  11. 21 CFR 888.3180 - Elbow joint humeral (hemi-elbow) metallic uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Elbow joint humeral (hemi-elbow) metallic uncemented prosthesis. 888.3180 Section 888.3180 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3180...

  12. 21 CFR 888.3180 - Elbow joint humeral (hemi-elbow) metallic uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Elbow joint humeral (hemi-elbow) metallic uncemented prosthesis. 888.3180 Section 888.3180 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3180...

  13. 21 CFR 888.3200 - Finger joint metal/metal constrained uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Finger joint metal/metal constrained uncemented prosthesis. 888.3200 Section 888.3200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3200 Finger joint...

  14. A new technique for radiographic measurement of acetabular cup orientation.

    PubMed

    Derbyshire, Brian; Diggle, Peter J; Ingham, Christopher J; Macnair, Rory; Wimhurst, James; Jones, Henry Wynn

    2014-02-01

    Accurate radiographic measurement of acetabular cup orientation is required in order to assess susceptibility to impingement, dislocation, and edge loading wear. In this study, the accuracy and precision of a new radiographic cup orientation measurement system were assessed and compared to those of two commercially available systems. Two types of resurfacing hip prostheses and an uncemented prosthesis were assessed. Radiographic images of each prosthesis were created with the cup set at different, known angles of version and inclination in a measurement jig. The new system was the most accurate and precise and could repeatedly measure version and inclination to within a fraction of a degree. In addition it has a facility to distinguish cup retroversion from anteversion on anteroposterior radiographs. © 2013.

  15. A Review of Periprosthetic Femoral Fractures Associated With Total Hip Arthroplasty

    PubMed Central

    Marsland, Daniel; Mears, Simon C.

    2012-01-01

    Periprosthetic fractures of the femur in association with total hip arthroplasty are increasingly common and often difficult to treat. Patients with periprosthetic fractures are typically elderly and frail and have osteoporosis. No clear consensus exists regarding the optimal management strategy because there is limited high-quality research. The Vancouver classification facilitates treatment decisions. In the presence of a stable prosthesis (type-B1 and -C fractures), most authors recommend surgical stabilization of the fracture with plates, strut grafts, or a combination thereof. In up to 20% of apparent Vancouver type-B1 fractures, the femoral stem is loose, which may explain the high failure rates associated with open reduction and internal fixation. Some authors recommend routine opening and dislocation of the hip to perform an intraoperative stem stability test to rule out a loose component. Advances in plating techniques and technology are improving the outcomes for these fractures. For fractures around a loose femoral prosthesis (types B2 and 3), revision using an extensively porous-coated uncemented long stem, with or without additional fracture fixation, appears to offer the most reliable outcome. Cement-in-cement revision using a long-stem prosthesis is feasible in elderly patients with a well-fixed cement mantle. It is essential to treat the osteoporosis to help fracture healing and to prevent further fractures. We provide an overview of the causes, classification, and management of periprosthetic femoral fractures around a total hip arthroplasty based on the current best available evidence. PMID:23569704

  16. Displaced intracapsular neck of femur fractures: Outcome of 810 hydroxyapetite coated (HAC) uncemented hemiarthroplasties.

    PubMed

    Nawaz, S Z; Keightley, A J; Desai, A; Granville-Chapman, J; Elliott, D; Newman, K; Khaleel, A

    2017-04-01

    A Cochrane review influenced new NICE guidelines, which recommended surgeons: Offer cemented implants to patients undergoing surgery with arthroplasty. However our trust routinely uses HAC uncemented stem (Taperloc ® , Biomet) hemiarthroplasties. A review of a consecutive series of uncemented HAC stem hemiarthroplasties including measures such as intro-operative complications, mortality and revision surgery. Prospectively collected data between January 2008 and June 2014 was used, with medical record and radiographic reviews performed. 810 consecutive Taperloc uncemented hemiarthroplasty with monopolar heads were performed in 763 patients, with a minimum 12 month follow-up (12-90) follow-up. Mean age 83yrs; 71% female. Meantime to operation was 28.5h. 30day mortality: 4.4% (33/763). One year mortality was 11.2% (89/763). 2.5% (20/810) were admitted on a separate admission with the periprosthetic fracture. 0.6% (5/810) were revised to total hip replacement for subsidence and associated pain. Only 1% (8/810) had intraoperative calcar fractures, all of which were treated with intraoperative cabling with no evidence of clinically relevant subsidence or medium term complications requiring revision surgery within a year. To the author's knowledge this is largest outcome series for modern design uncemented hemiarthroplasty. Our study shows comparable data to cemented hemiarthroplasty but no deaths in the first 2days post-op. Our series also demonstrates a well below average mortality figures which are clearly multifactorial but believe uncemented prosthesis play a role. We believe that uncemented proven stem design hemiarthroplasty remains a safe and good surgical option for displaced intracapsular fractures. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

  17. Basic Science Considerations in Primary Total Hip Replacement Arthroplasty

    PubMed Central

    Mirza, Saqeb B; Dunlop, Douglas G; Panesar, Sukhmeet S; Naqvi, Syed G; Gangoo, Shafat; Salih, Saif

    2010-01-01

    Total Hip Replacement is one of the most common operations performed in the developed world today. An increasingly ageing population means that the numbers of people undergoing this operation is set to rise. There are a numerous number of prosthesis on the market and it is often difficult to choose between them. It is therefore necessary to have a good understanding of the basic scientific principles in Total Hip Replacement and the evidence base underpinning them. This paper reviews the relevant anatomical and biomechanical principles in THA. It goes on to elaborate on the structural properties of materials used in modern implants and looks at the evidence base for different types of fixation including cemented and uncemented components. Modern bearing surfaces are discussed in addition to the scientific basis of various surface engineering modifications in THA prostheses. The basic science considerations in component alignment and abductor tension are also discussed. A brief discussion on modular and custom designs of THR is also included. This article reviews basic science concepts and the rationale underpinning the use of the femoral and acetabular component in total hip replacement. PMID:20582240

  18. More complications with uncemented than cemented femoral stems in total hip replacement for displaced femoral neck fractures in the elderly

    PubMed Central

    Chammout, Ghazi; Muren, Olle; Laurencikas, Evaldas; Bodén, Henrik; Kelly-Pettersson, Paula; Sjöö, Helene; Stark, André; Sköldenberg, Olof

    2017-01-01

    Background and purpose Total hip replacement (THR) is the preferred method for the active and lucid elderly patient with a displaced femoral neck fracture (FNF). Controversy still exists regarding the use of cemented or uncemented stems in these patients. We compared the effectiveness and safety between a modern cemented, and a modern uncemented hydroxyapatite-coated femoral stem in patients 65–79 years of age who were treated with THR for displaced FNF. Patients and methods In a single-center, single-blinded randomized controlled trial, we included 69 patients, mean age 75 (65–79) and with a displaced FNF (Garden III–IV). 35 patients were randomized to a cemented THR and 34 to a reverse-hybrid THR with an uncemented stem. Primary endpoints were: prevalence of all hip-related complications and health-related quality of life, evaluated with EuroQol-5D (EQ-5D) index up to 2 years after surgery. Secondary outcomes included: overall mortality, general medical complications, and hip function. The patients were followed up at 3, 12, and 24 months. Results According to the calculation of sample size, 140 patients would be required for the primary endpoints, but the study was stopped when only half of the sample size was included (n = 69). An interim analysis at that time showed that the total number of early hip-related complications was substantially higher in the uncemented group, 9 (among them, 3 dislocations and 4 periprosthetic fractures) as compared to 1 in the cemented group. The mortality and functional outcome scores were similar in the 2 groups. Interpretation We do not recommend uncemented femoral stems for the treatment of elderly patients with displaced FNFs. PMID:27967333

  19. Revision of a Fractured Uncemented Revision Stem Using a Custom Designed Punch and Retrograde Through-Knee Approach

    PubMed Central

    Nasr, P. J.; Keene, G. S.

    2015-01-01

    We report a unique case of a fractured modular cobalt chromium connection taper Revitan (Zimmer, Warsaw, IN) revision prosthesis. Macroscopic examination revealed a fracture at the diaphyseal-metaphyseal junction of this modular component. This report highlights that fractures can still occur with modern modular prostheses. We are not aware of any published failures of the Revitan revision prosthesis. We also describe a unique method of retrieval for a broken well fixed uncemented femoral stem, using a custom designed extraction instrument via a through-knee approach. PMID:25793134

  20. 21 CFR 888.3670 - Shoulder joint metal/polymer/metal nonconstrained or semi-constrained porous-coated uncemented...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Shoulder joint metal/polymer/metal nonconstrained... ORTHOPEDIC DEVICES Prosthetic Devices § 888.3670 Shoulder joint metal/polymer/metal nonconstrained or semi-constrained porous-coated uncemented prosthesis. (a) Identification. A shoulder joint metal/polymer/metal...

  1. Uncemented three-dimensional-printed prosthetic replacement for giant cell tumor of distal radius: a new design of prosthesis and surgical techniques.

    PubMed

    Lu, Minxun; Min, Li; Xiao, Cong; Li, Yongjiang; Luo, Yi; Zhou, Yong; Zhang, Wenli; Tu, Chongqi

    2018-01-01

    Currently, it is challenging to treat giant cell tumor (GCT) of distal radius. For Campanacci grade III or recurrent GCTs, en bloc resection has been accepted as a better treatment option. Although numerous methods are available for reconstruction, all of them have some limitations in joint function and complications. In this study, our aims were to treat the GCT of distal radius with uncemented three-dimensional (3D)-printed prosthesis and to present and evaluate the surgical techniques and short-term outcomes. Between September 2015 and March 2017, 11 patients with distal radius GCTs were treated with personalized uncemented 3D-printed prosthesis. The preoperative/postoperative pain, range of motion, and grip strengths of all patients were evaluated. Oncological results, complications, and degenerative changes in the wrist joint were evaluated. Functional outcomes were assessed according to the disabilities of the arm, shoulder, and hand (DASH) questionnaire and Mayo wrist scoring systems. The average follow-up was 14.45 months (range, 8-18 months). There was a significant decrease in the mean postoperative visual analog scale score (2.33) compared with the preoperative score (5.22; p <0.001). The mean DASH score and Mayo wrist score of the wrist joint function were 18.7 and 72, respectively. There was no local recurrence or lung metastasis. No complication associated with prosthesis was observed, including aseptic loosening, subluxation, and breakage. Joint space narrowing, or disuse osteoporosis, was also not found in all cases. En bloc resection and reconstruction with a personalized uncemented 3D-printed prosthesis can be alternative options to treat Campanacci grade III or recurrent GCTs of distal radius and can result in short-term oncologic salvage, good postoperative function, and low complication rate. However, a long-term follow-up is required to determine the outcome.

  2. Stability of Uncemented Cups - Long-Term Effect of Screws, Pegs and HA Coating: A 14-Year RSA Follow-Up of Total Hip Arthroplasty.

    PubMed

    Otten, Volker T C; Crnalic, Sead; Röhrl, Stephan M; Nivbrant, Bo; Nilsson, Kjell G

    2016-01-01

    Screws, pegs and hydroxyapatite-coating are used to enhance the primary stability of uncemented cups. We present a 14-year follow-up of 48 hips randomized to four groups: press-fit only, press-fit plus screws, press-fit plus pegs and hydroxyapatite-coated cups. Radiostereometric migration measurements showed equally good stability regardless cup augmentation. The mean wear rate was high, 0.21 mm/year, with no differences between the groups. Seven hips had radiographical osteolysis but only in hips with augmented cups. Cups without screw-holes compared with cups with screw-holes resulted in better clinical outcome at the 14-year follow-up. Thus, augmentation of uncemented cups with screws, pegs, or hydroxyapatite did not appear to improve the long-term stability compared with press-fit only. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Negligence claims in UK total hip arthroplasty: a series of 167 consecutive cases.

    PubMed

    Whittingham-Jones, Paul; Williams, D; Raja, S; Bridle, S; Bircher, M

    2012-01-01

    A review of negligence reports, detailing 227 complaints from the practices of two orthopedic surgeons, was undertaken. There were demonstrable differences in the number of complaints over leg-length discrepancy; femoral fracture and cup malposition when cemented versus uncemented implants were compared. Surgeons must appreciate the less forgiving nature of uncemented hip implants and the importance of preoperative planning particularly in the presence of abnormal anatomy.

  4. Stem geometry changes initial femoral fixation stability of a revised press-fit hip prosthesis: A finite element study.

    PubMed

    Russell, Robert D; Huo, Michael H; Rodrigues, Danieli C; Kosmopoulos, Victor

    2016-11-14

    Stable femoral fixation during uncemented total hip arthroplasty is critical to allow for subsequent osseointegration of the prosthesis. Varying stem designs provide surgeons with multiple options to gain femoral fixation. The purpose of this study was to compare the initial fixation stability of cylindrical and tapered stem implants using two different underreaming techniques (press-fit conditions) for revision total hip arthroplasty (THA). A finite element femur model was created from three-dimensional computed tomography images simulating a trabecular bone defect commonly observed in revision THA. Two 18-mm generic femoral hip implants were modeled using the same geometry, differing only in that one had a cylindrical stem and the other had a 2 degree tapered stem. Surgery was simulated using a 0.05-mm and 0.01-mm press-fit and tested with a physiologically relevant loading protocol. Mean contact pressure was influenced more by the surgical technique than by the stem geometry. The 0.05-mm press-fit condition resulted in the highest contact pressures for both the cylindrical (27.35 MPa) and tapered (20.99 MPa) stems. Changing the press-fit to 0.01-mm greatly decreased the contact pressure by 79.8% and 78.5% for the cylindrical (5.53 MPa) and tapered (4.52 MPa) models, respectively. The cylindrical stem geometry consistently showed less relative micromotion at all the cross-sections sampled as compared to the tapered stem regardless of press-fit condition. This finite element analysis study demonstrates that tapered stem results in lower average contact pressure and greater micromotion at the implant-bone interface than a cylindrical stem geometry. More studies are needed to establish how these different stem geometries perform in such non-ideal conditions encountered in revision THA cases where less bone stock is available.

  5. A cemented cup with acetabular impaction bone grafting is more cost-effective than an uncemented cup in patients under 50 years.

    PubMed

    Busch, Vincent J J F; Verschueren, Joost; Adang, Eddy M; Lie, Stein A; Havelin, Leif I; Schreurs, Berend W

    2016-01-01

    Acetabular deficiencies in young patients can be restored in several ways during total hip arthroplasty. Currently, cementless cups are most frequently used. Impaction bone grafting of acetabular defects is a more biological approach, but is it cost-effective in young patients on the long term? We designed a decision model for a cost-utility analysis of a cemented cup with acetabular impaction bone grafting versus an uncemented cup, in terms of cost per quality-adjusted life year (QALY) for the young adult with acetabular bone deficiency, in need for a primary total hip arthroplasty. Outcome probabilities and effectiveness were derived from the Radboud University Nijmegen Medical Centre and the Norwegian Hip Register. Multiple sensitivity analyses were used to assess the contribution of the included variables in the model's outcome. Cemented cups with impaction bone grafting were more cost-effective compared to the uncemented option in terms of costs per QALY. A scenario suggesting equal primary survival rates of both cemented and uncemented cups still showed an effect gain of the cemented cup with impaction bone grafting, but at higher costs. Based on this model, the first choice of treatment of the acetabular bone deficient osteoarthritic hip in a young patient is reconstruction with impaction bone grafting and a cemented cup.

  6. 10-year results of the uncemented Allofit press-fit cup in young patients.

    PubMed

    Streit, Marcus R; Weiss, Stefan; Andreas, Franziska; Bruckner, Thomas; Walker, Tilman; Kretzer, J Philippe; Ewerbeck, Volker; Merle, Christian

    2014-08-01

    Uncemented acetabular components in primary total hip arthroplasty (THA) are commonly used today, but few studies have evaluated their survival into the second decade in young and active patients. We report on a minimum 10-year follow-up of an uncemented press-fit acetabular component that is still in clinical use. We examined the clinical and radiographic results of our first 121 consecutive cementless THAs using a cementless, grit-blasted, non-porous, titanium alloy press-fit cup (Allofit; Zimmer Inc., Warsaw, IN) without additional screw fixation in 116 patients. Mean age at surgery was 51 (21-60) years. Mean time of follow-up evaluation was 11 (10-12) years. At final follow-up, 8 patients had died (8 hips), and 1 patient (1 hip) was lost to follow-up. 3 hips in 3 patients had undergone acetabular revision, 2 for deep infection and 1 for aseptic acetabular loosening. There were no impending revisions at the most recent follow-up. We did not detect periacetabular osteolysis or loosening on plain radiographs in those hips that were evaluated radiographically (n = 90; 83% of the hips available at a minimum of 10 years). Kaplan-Meier survival analysis using revision of the acetabular component for any reason (including isolated inlay revisions) as endpoint estimated the 11-year survival rate at 98% (95% CI: 92-99). Uncemented acetabular fixation using the Allofit press-fit cup without additional screws was excellent into early in the second decade in this young and active patient cohort. The rate of complications related to the liner and to osteolysis was low.

  7. Differences in Femoral Head Penetration Between Highly Cross-Linked Polyethylene Cemented Sockets and Uncemented Liners.

    PubMed

    Morita, Daigo; Seki, Taisuke; Higuchi, Yoshitoshi; Takegami, Yasuhiko; Ishiguro, Naoki

    2017-12-01

    This study aimed at investigating differences in femoral head penetration between highly cross-linked polyethylene (HXLPE) cemented sockets and uncemented liners during 5 years postoperatively. Ninety-six patients (106 hips) with a mean age of 64.4 (range, 35-83) years underwent total hip arthroplasty using a HXLPE cemented socket or liner and were respectively divided into cemented (35 patients [37 hips]) and uncemented (61 patients [69 hips]) groups. Femoral head penetrations were evaluated on both anteroposterior (AP)-view and Lauenstein-view radiographs, and mean polyethylene (PE) wear rates were calculated based on femoral head penetration from 2 to 5 years. Multivariate analyses were performed to assess risk factors for PE wear. At 5 years postoperatively, the cemented and uncemented groups exhibited proximal direction femoral head penetrations of 0.103 mm and 0.124 mm (P = .226) and anterior direction penetrations of 0.090 mm and 0.151 mm (P = .002), respectively. The corresponding mean PE wear rates were 0.004 mm/y and 0.009 mm/y in the AP-view (P = .286) and 0.005 mm/y and 0.012 mm/y in the Lauenstein-view (P = .168), respectively. Left-side operation and high activity were independent risk factors for PE wear on AP-view. When HXLPE was used, all mean PE wear rates were very low and those of cemented sockets and uncemented liners were very similar. PE particle theory suggests that the occurrence of osteolysis and related aseptic loosening might consequently decrease. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Recognizing anterior metaphyseal femoral bone loss during uncemented total hip arthroplasty: the skylight sign.

    PubMed

    Harwin, Steven F

    2007-03-01

    During preparation for uncemented femoral arthroplasty, a phenomenon has been observed that indicates thinning of anterior metaphyseal bone to a critical level. Light can be seen from within the canal passing through the anterior cortex. This skylight sign alerts the surgeon that a cortical defect or fracture can occur on reaming, broaching, or component insertion. In 420 consecutive arthroplasties, a skylight sign was noted in 97 (23%) hips. In 5 of those hips an oval cortical defect was created and in 3 hips a fracture occurred during broaching or insertion. Loosening developed in 1 hip with fracture. No fractures or defects occurred in hips without a skylight sign. If a skylight sign is present, the femur is at risk and preventive measures should be taken.

  9. Rationale for one stage exchange of infected hip replacement using uncemented implants and antibiotic impregnated bone graft.

    PubMed

    Winkler, Heinz

    2009-09-04

    Infection of a total hip replacement (THR) is considered a devastating complication, necessitating its complete removal and thorough debridement of the site. It is undoubted that one stage exchange, if successful, would provide the best benefit both for the patient and the society. Still the fear of re-infection dominates the surgeons decisions and in the majority of cases directs them to multiple stage protocols. However, there is no scientifically based argument for that practice. Successful eradication of infection with two stage procedures is reported to average 80% to 98%. On the other hand a literature review of Jackson and Schmalzried (CORR 2000) summarizing the results of 1,299 infected hip replacements treated with direct exchange (almost exclusively using antibiotic loaded cement), reports of 1,077 (83%) having been successful. The comparable results suggest, that the major factor for a successful outcome with traditional approaches may be found in the quality of surgical debridement and dead space management. Failures in all protocols seem to be caused by small fragments of bacterial colonies remaining after debridement, whereas neither systemic antibiotics nor antibiotic loaded bone cement (PMMA) have been able to improve the situation significantly. Reasons for failure may be found in the limited sensitivity of traditional bacterial culturing and reduced antibiotic susceptibility of involved pathogens, especially considering biofilm formation. Whenever a new prosthesis is implanted into a previously infected site the surgeon must be aware of increased risk of failure, both in single or two stage revisions. Eventual removal therefore should be easy with low risk of additional damage to the bony substance. On the other hand it should also have potential of a good long term result in case of success. Cemented revisions generally show inferior long term results compared to uncemented techniques; the addition of antibiotics to cement reduces its biomechanical properties. Efficient cementing techniques will result in tight bonding with the underlying bone, making eventual removal time consuming and possibly associated with further damage to the osseous structures. All these issues are likely to make uncemented revisions more desirable. Allograft bone may be impregnated with high loads of antibiotics using special incubation techniques. The storage capacities and pharmacological kinetics of the resulting antibiotic bone compound (ABC) are more advantageous than the ones of antibiotic loaded cement. ABC provides local concentrations exceeding those of cement by more than a 100fold and efficient release is prolonged for several weeks. The same time they are likely to restore bone stock, which usually is compromised after removal of an infected endoprosthesis. ABC may be combined with uncemented implants for improved long term results and easy removal in case of a failure. Specifications of appropriate designs are outlined. Based on these considerations new protocols for one stage exchange of infected TJR have been established. Bone voids surrounding the implants may be filled with antibiotic impregnated bone graft; uncemented implants may be fixed in original bone. Recent studies indicate an overall success rate of more than 90% without any adverse side effects. Incorporation of allografts appears as after grafting with unimpregnated bone grafts. Antibiotic loaded bone graft seems to provide sufficient local antibiosis for protection against colonisation of uncemented implants, the eluted amounts of antibiotics are likely to eliminate biofilm remnants, dead space management is more complete and defects may be reconstructed efficiently. Uncemented implants provide improved long term results in case of success and facilitated re-revision in case of failure. One stage revision using ABC together with uncemented implants such should be at least comparably save as multiple stage procedures, taking advantage of the obvious benefits for patients and economy.

  10. Uncemented total hip arthroplasty in chronic hemodialysis patients

    PubMed Central

    Li, Wei-Chun; Shih, Chun-Hsiung; Ueng, Steve W; Shih, Hsin-Nung; Lee, Mel S

    2010-01-01

    Background and purpose Whether or not uncemented total hip arthroplasty (THA) can achieve durable fixation of implants to bone in patients on chronic hemodialysis is unknown. We analyzed the 2–13-year clinical outcomes of cementless THA in patients with end-stage renal diseases who were maintained on long-term hemodialysis. Patients and methods We reviewed the outcome of 23 consecutive uncemented THAs undertaken between 1993 and 2004, in patients with chronic renal failure who had been on long-term hemodialysis (2–18 years). 1 patient died and 2 patients were lost to follow-up within 2 years, leaving 20 hips (20 patients, median age 66 (38–81) years at the time of THA, 11 females) that were reviewed at median 7 (2–13) years postoperatively. Results Radiographic bone-ingrowth fixation of the components was found in 19 patients. 1 patient had aseptic loosening requiring revision surgery. The median d'Aubigne and Postel score was 10 (8–14) preoperatively and 15 (12–18) at final review. No prosthetic infections were found in any of the patients. Interpretation Uncemented THA shows promising medium-term results in patients receiving long-term hemodialysis. PMID:20175645

  11. Reduced survival for uncemented compared to cemented total hip arthroplasty after operatively treated acetabular fractures.

    PubMed

    Clarke-Jenssen, John; Westberg, Marianne; Røise, Olav; Storeggen, Stein Arne Øvre; Bere, Tone; Silberg, Ingunn; Madsen, Jan Erik

    2017-11-01

    Post traumatic arthritis and avascular necrosis of the femoral head are common complications after operatively treated acetabular fractures. This may cause severe disabilities for the patient, necessitating a total hip arthroplasty. Even though an arthroplasty may provide good symptomatic relief, the long-term results are more uncertain and no consensus exists according to preferred prosthetic designs. With this cohort study, we aimed to investigate the medium to long term arthroplasty survival and clinical results of total hip arthroplasty after operatively treated acetabular fractures. We included 52 patients treated with a secondary total hip arthroplasty at a median of 2.4 (0.1-14.1) years after an operatively treated acetabular fracture. The median age was 54 (11-82) years. Cemented arthroplasty was used for 33 patients, 10 patients had an uncemented arthroplasty and 9 patients received a hybrid arthroplasty. Average follow up was 8.0 (SD 5.0) years. Ten-year revision free arthroplasty survival was 79%. Uncemented arthroplasties had a significantly worse 10-year survival of 57%. Arthroplasties performed at a centre without a pelvic fracture service also had a significantly worse 10-years survival of 51%. Cox regression showed similar results with an 8-fold increase in risk of revision for both uncemented arthroplasties and operations performed at a non-pelvic trauma centre. Total hip arthroplasty secondary to an operatively treated acetabular fracture provides good symptomatic relief. These patients are, however, complex cases and are probably best treated at specialist centres with both pelvic trauma surgeons and arthroplasty surgeons proficient in complex revisions present. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Estimated survival probability of the Spotorno total hip arthroplasty after a 15- to 21-year follow-up: one surgeon's results.

    PubMed

    Terré, Ricardo A

    2010-01-01

    We retrospectively assess 171 consecutive total hip arthroplasties (THAs) with a Spotorno CLS uncemented prosthesis implanted through a Hardinge approach. The mean follow-up was 17.9 years. All consecutive operations were performed by 1 surgeon. Eight patients had been lost to follow-up, and 77 had died for unrelated causes. Overall, 4 stems and 19 cups underwent revision. The cumulative survival rate at 21 years was 79.02% (95% confidence interval [95% CI], 45.98-100.00%) for the acetabular component and 96.71% (95% CI, 60.71-100.00%) for the stem. We can conclude that failure of the Spotorno CLS THA is mainly due to its acetabular component (relative risk 4.5). Survival results for the Spotorno CLS stem exceed the patients? life expectancies in the 60- to 70-year-old population in our area. Loosening with or without fatigue fracture of the component and the learning curve for proper implantation have been the main causes for the expansion cup failure.

  13. Difference in Postoperative Periprosthetic Bone Mineral Density Changes Between 3 Major Designs of Uncemented Stems: A 3-Year Follow-Up Study.

    PubMed

    Inaba, Yutaka; Kobayashi, Naomi; Oba, Masatoshi; Ike, Hiroyuki; Kubota, So; Saito, Tomoyuki

    2016-08-01

    Although few studies have examined the direct effect of stress shielding on clinical outcomes, periprosthetic bone loss due to stress shielding is still an issue of concern, especially when physicians perform uncemented total hip arthroplasty (THA) in younger patients. Differences in femoral stem design may affect the degree of postoperative stress shielding. Therefore, the characteristics of the behavior for stress shielding of each type of femoral stem should be determined. This study compares differences in bone mineral density (BMD) change in the femur after primary THA between 3 major types of uncemented stems. Among a total of 89 hips, 26 hips received THA with a fit-and-fill type stem (VerSys Fiber Metal MidCoat; Zimmer, Inc, Warsaw, IN), 32 hips received a tapered rectangular Zweymüller-type stem (SL-Plus; Smith & Nephew Inc, Memphis, TN), and 31 received a tapered wedge-type stem (Accolade TMZF; Stryker Orthopaedics, Mahwah, NJ). BMD measurements were performed with a HOLOGIC Discovery device (Hologic Inc, Waltham, MA). BMD in the medial-proximal femur was maintained for 3 years after THA in the group with the tapered wedge-type stem. BMD in the lateral-proximal femur was maintained for 3 years after THA in the group with the Zweymüller-type stem. There were no significant differences in the Harris Hip Score among the 3 stem groups preoperatively and 1, 2, and 3 years after surgery. There are clear differences in postoperative BMD loss of the proximal femur among these 3 commonly used uncemented stems. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Undisplaced Intraoperative Fracture Presenting as Early Dislocation with Tapered Wedge Stems in Total Hip Arthroplasty - Case Series and Review of Literature

    PubMed Central

    Reddy, A V Gurava; Eachempati, Krishna Kiran; Mugalur, Aakash; Suchinder, A; Rao, V B N Prasad; Kamurukuru, Nalanda

    2017-01-01

    Introduction: Periprosthetic fractures and dislocation in the early post-operative period can be disastrous both for the surgeon and the patient. However, undisplaced periprosthetic fractures presenting with dislocation is uncommon. We describe successful management of two cases (one bilateral dislocation and one unilateral dislocation) of undisplaced iatrogenic fractures in total hip arthroplasty (THA) presenting as early dislocation. Case Report: Case 1 was a 45-year-old female with osteoarthritis of hip secondary to developmental dysplasia of the hip with bilateral early nontraumatic dislocation with bilateral identical periprosthetic fracture. It was managed by revision to long stem and encirclage wiring. Case 2 presented with early dislocation in the 2nd week post THA. We found an intertrochanteric fracture intra-operatively with unstable implant. Acetabular component and femoral component revision were done with reconstruction of the greater trochanter. Discussion: These fractures could be occult iatrogenic fractures characteristic of taper wedge stems which presented as early nontraumatic dislocation in the post-operative period. The prosthesis subsidence, loss of muscle tension and change of version might be the factors leading to dislocation. Conclusion: Unrecognized incomplete intraoperative fracture can occur with tapered wedge uncemented stems which can present as a dislocation in the immediate post-operative period. This will require early revision of the femoral component. PMID:29051875

  15. Transfemoral implantation of the Wagner SL stem. The abolition of subsidence and enhancement of osteotomy union rate using Dall-Miles cables.

    PubMed

    Warren, P J; Thompson, P; Fletcher, M D A

    2002-12-01

    The Wagner SL uncemented revision stem has been utilised successfully for revision hip surgery where marked loss of proximal bone stock co-exists or where there is a periprosthetic fracture. Implanted via the transfemoral approach, one significant difficulty appears to be a tendency for implant subsidence, which in some cases has been troublesome enough to necessitate early revision (usually to a larger prosthesis). A change in our operative practice allowed us to review the effects of using either wire cerclages or 2.0 mm Dall-Miles cables for prophylactic wiring of the distal femur. Seventeen Wagner SL stems, inserted via the transfemoral approach, were studied in 16 patients. We found those patients prophylactically wired with Dall-Miles cables demonstrated no subsidence in comparison with those in whom heavy wire cerclage had been utilised (mean subsidence 6 mm; p=0.001). In addition, we found that closure of the proximal osteotomy with wires conferred a more reliable rate of union in comparison with those closed with heavy sutures. We recommend the use of Dall-Miles cables for distal cerclage and osteotomy closure for the Wagner prosthesis.

  16. 21 CFR 888.3370 - Hip joint (hemi-hip) acetabular metal cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint (hemi-hip) acetabular metal cemented... (hemi-hip) acetabular metal cemented prosthesis. (a) Identification. A hip joint (hemi-hip) acetabular metal cemented prosthesis is a device intended to be implanted to replace a portion of the hip joint...

  17. A new system of computer-assisted navigation leading to reduction in operating time in uncemented total hip replacement in a matched population.

    PubMed

    Chaudhry, Fouad A; Ismail, Sanaa Z; Davis, Edward T

    2018-05-01

    Computer-assisted navigation techniques are used to optimise component placement and alignment in total hip replacement. It has developed in the last 10 years but despite its advantages only 0.3% of all total hip replacements in England and Wales are done using computer navigation. One of the reasons for this is that computer-assisted technology increases operative time. A new method of pelvic registration has been developed without the need to register the anterior pelvic plane (BrainLab hip 6.0) which has shown to improve the accuracy of THR. The purpose of this study was to find out if the new method reduces the operating time. This was a retrospective analysis of comparing operating time in computer navigated primary uncemented total hip replacement using two methods of registration. Group 1 included 128 cases that were performed using BrainLab versions 2.1-5.1. This version relied on the acquisition of the anterior pelvic plane for registration. Group 2 included 128 cases that were performed using the newest navigation software, BrainLab hip 6.0 (registration possible with the patient in the lateral decubitus position). The operating time was 65.79 (40-98) minutes using the old method of registration and was 50.87 (33-74) minutes using the new method of registration. This difference was statistically significant. The body mass index (BMI) was comparable in both groups. The study supports the use of new method of registration in improving the operating time in computer navigated primary uncemented total hip replacements.

  18. Higher failure rate and stem migration of an uncemented femoral component in patients with femoral head osteonecrosis than in patients with osteoarthrosis.

    PubMed

    Radl, Roman; Hungerford, Marc; Materna, Wilfried; Rehak, Peter; Windhager, Reinhard

    2005-02-01

    Several authors have found poorer outcome after hip replacement for osteonecrosis than after hip replacement for arthrosis. In a retrospective study we evaluated the performance of an uncemented femoral component in patients with osteonecrosis and arthrosis of the hip. 31 patients operated for osteonecrosis, and 49 patients operated for osteoarthrosis were included. The median follow-up time was 6.1 (2-11) years for the patients with osteonecrosis, and 5.9 (4-8) for the arthrosis patients. Migration analysis performed by the Einzel-Bild-Roentgen Analysis (EBRA) technique revealed a median stem migration of 1.5 (-8.8-0) mm in the patients with osteonecrosis, but only 0.6 (-2.8-0.7) mm in the patients with arthrosis (p < 0.001). Survivorship analysis with stem revision as endpoint for failure was 74% (95% CI: 55-94) in the osteonecrosis, and 98% (95% CI: 94-100) in the arthrosis group (p = 0.01). We suggest that the higher failure rate and stem migration of uncemented total hip replacement in the patients with osteonecrosis is a consequence of the disease. On the basis of these findings, we recommend close monitoring of the patients with osteonecrosis, which should include migration measurements.

  19. Do financial incentives trump clinical guidance? Hip Replacement in England and Scotland.

    PubMed

    Papanicolas, Irene; McGuire, Alistair

    2015-12-01

    Following devolution in 1999 England and Scotland's National Health Services diverged, resulting in major differences in hospital payment. England introduced a case payment mechanism from 2003/4, while Scotland continued to pay through global budgets. We investigate the impact this change had on activity for Hip Replacement. We examine the financial reimbursement attached to uncemented Hip Replacement in England, which has been more generous than for its cemented counterpart, although clinical guidance from the National Institute for Clinical Excellence recommends the later. In Scotland this financial differential does not exist. We use a difference-in-difference estimator, using Scotland as a control, to test whether the change in reimbursement across the two countries had an influence on treatment. Our results indicate that financial incentives are directly linked to the faster uptake of the more expensive, uncemented Hip Replacement in England, which ran against the clinical guidance. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. 21 CFR 888.3535 - Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... across-the-joint. This generic type of device is designed to achieve biological fixation to bone without the use of bone cement. This identification includes fixed-bearing knee prostheses where the ultra...

  1. 21 CFR 888.3535 - Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... across-the-joint. This generic type of device is designed to achieve biological fixation to bone without the use of bone cement. This identification includes fixed-bearing knee prostheses where the ultra...

  2. 21 CFR 888.3535 - Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... across-the-joint. This generic type of device is designed to achieve biological fixation to bone without the use of bone cement. This identification includes fixed-bearing knee prostheses where the ultra...

  3. 21 CFR 888.3535 - Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... across-the-joint. This generic type of device is designed to achieve biological fixation to bone without the use of bone cement. This identification includes fixed-bearing knee prostheses where the ultra...

  4. 21 CFR 888.3535 - Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... across-the-joint. This generic type of device is designed to achieve biological fixation to bone without the use of bone cement. This identification includes fixed-bearing knee prostheses where the ultra...

  5. 21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... degenerative and posttraumatic patellar arthritis. (2) Class III when intended for uses other than treatment of degenerative and posttraumatic patellar arthritis. (c) Date PMA or notice of completion of a PDP is required. A...

  6. 21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... degenerative and posttraumatic patellar arthritis. (2) Class III when intended for uses other than treatment of degenerative and posttraumatic patellar arthritis. (c) Date PMA or notice of completion of a PDP is required. A...

  7. 21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... degenerative and posttraumatic patellar arthritis. (2) Class III when intended for uses other than treatment of degenerative and posttraumatic patellar arthritis. (c) Date PMA or notice of completion of a PDP is required. A...

  8. 21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... degenerative and posttraumatic patellar arthritis. (2) Class III when intended for uses other than treatment of degenerative and posttraumatic patellar arthritis. (c) Date PMA or notice of completion of a PDP is required. A...

  9. Per-operative vibration analysis: a valuable tool for defining correct stem insertion: preliminary report.

    PubMed

    Mulier, Michiel; Pastrav, Cesar; Van der Perre, Georges

    2008-01-01

    Defining the stem insertion end point during total hip replacement still relies on the surgeon's feeling. When a custom-made stem prosthesis with an optimal fit into the femoral canal is used, the risk of per-operative fractures is even greater than with standard prostheses. Vibration analysis is used in other clinical settings and has been tested as a means to detect optimal stem insertion in the laboratory. The first per-operative use of vibration analysis during non-cemented custom-made stem insertion in 30 patients is reported here. Thirty patients eligible for total hip replacement with uncemented stem prosthesis were included. The neck of the stem was connected with a shaker that emitted white noise as excitation signal and an impedance head that measured the frequency response. The response signal was sent to a computer that analyzed the frequency response function after each insertion phase. A technician present in the operating theatre but outside the laminated airflow provided feed-back to the surgeon. The correlation index between the frequency response function measured during the last two insertion hammering sessions was >0.99 in 86.7% of the cases. In four cases the surgeon stopped the insertion procedure because of a perceived risk of fracture. Two special cases illustrating the potential benefit of per-operative vibration analysis are described. The results of intra-operative vibration analysis indicate that this technique may be a useful tool assisting the orthopaedic surgeon in defining the insertion endpoint of the stem. The development of a more user-friendly device is therefore warranted.

  10. The influence of uncemented femoral stem length and design on its primary stability: a finite element analysis.

    PubMed

    Reimeringer, M; Nuño, N; Desmarais-Trépanier, C; Lavigne, M; Vendittoli, P A

    2013-01-01

    One of the crucial factors for short- and long-term clinical success of total hip arthroplasty cementless implants is primary stability. Indeed, motion at the bone-implant interface above 40 μm leads to partial bone ingrowth, while motion exceeding 150 μm completely inhibits bone ingrowth. The aim of this study was to investigate the effect of two cementless femoral stem designs with different lengths on the primary stability. A finite element model of a composite Sawbones(®) fourth generation, implanted with five lengths of the straight prosthesis design and four lengths of the curved prosthesis design, was loaded with hip joint and abductor forces representing two physiological activities: fast walking and stair climbing. We found that reducing the straight stem length from 146 to 54 mm increased the average micromotion from 17 to 52 μm during fast walking, while the peak value increased from 42 to 104 μm. With the curved stem, reducing length from 105 to 54 mm increased the average micromotion from 10 to 29 μm, while the peak value increased from 37 to 101 μm. Similar findings are obtained for stair climbing for both stems. Although the present study showed that femoral stem length as well as stem design directly influences its primary stability, for the two femoral stems tested, length could be reduced substantially without compromising the primary stability. With the aim of minimising surgical invasiveness, newer femoral stem design and currently well performing stems might be used with a reduced length without compromising primary stability and hence, long-term survivorship.

  11. Design modifications of the uncemented Furlong hip stem result in minor early subsidence but do not affect further stability: a randomized controlled RSA study with 5-year follow-up.

    PubMed

    Weber, Erik; Sundberg, Martin; Flivik, Gunnar

    2014-12-01

    Even small design modifications of uncemented hip stems may alter the postoperative 3-D migration pattern. The Furlong Active is an uncemented femoral stem which, in terms of design, is based on its precursor-the well-proven Furlong HAC-but has undergone several design changes. The collar has been removed on the Active stem along with the lateral fin; it is shorter and has more rounded edges in the proximal part. We compared the migration patterns of the uncemented Furlong HAC stem and the modified Furlong Active stem in a randomized, controlled trial over 5 years using radiostereometry (RSA). 50 patients with primary osteoarthritis were randomized to receive either the HAC stem or the Active stem. The patients underwent repeated RSA examinations (postoperatively, at 3 months, and after 1, 2, and 5 years) and conventional radiography, and they also filled out hip-specific questionnaires. During the first 3 months, the collarless Active stem subsided to a greater extent than the collar-fitted HAC stem (0.99 mm vs. 0.31 mm, p=0.05). There were, however, no other differences in movement measured by RSA or in clinical outcome between the 2 stems. After 3 months, both stem types had stabilized and almost no further migration was seen. The Active stem showed no signs of unfavorable migration. Our results suggest that the osseointegration is not compromised by the new design features.

  12. [Comparison of early clinical effects of two hip prosthesis designs between ceramics to ceramics and metal to polyethylene].

    PubMed

    Yang, Li-qing; Li, Xi; Fu, Qin; Wang, Cheng

    2013-07-01

    To retrospectively study early therapeutic effects of the ceramics to ceramics prosthesis design in treating hip disease. From October 2007 to September 2010, 42 patients (44 hips) with hip disease underwent replacement of total hip. Hip prosthesis designs included the Pinnacle ceramics to ceramics and the Duraloc metal to polyethylene,produced by DePuy Company, all were non-bone cement type of artificial hip joint. Twenty patients (22 hips) were performed with ceramics to ceramics total hip prosthesis (CoC group, there were 12 males and 8 females, aged from 21 to 49 years) and 22 patients (22 hips) were performed with metal to polyethylene total hip prosthesis (MoP group, there were 13 males and 9 females, aged from 42 to 55 years). All the surgical approachs were posterolateral, and the routine anticoagulation and the corresponding functional exercise were performed after operation. The follow-up time was 6 months at least including clinical and radiographic observation. Measured the motion of joint and evaluated the function of hip joint according to Harris classification. All clinical effects were satisfactory and no dislocation ,loosening,infection, deep venous thrombosis and other complications occurred. There was no statistical significance in Harris scoring and the motion of joint between two groups before and after operation (P>0.05). The clinical effect of ceramics to ceramics prosthesis design in improving clinical symptoms and the motion of joint is coordinate with metal to polyethylene total hip prosthesis, however, its advantages and long-term efficacy need further observing. The ceramics to ceramics prosthesis design may be a good choice for the young patients with hip disease because of its good wear resistance.

  13. Uncemented total hip arthroplasty in octogenarian and nonagenarian patients.

    PubMed

    Toro, Giuseppe; Bothorel, Hugo; Saffarini, Mo; Jacquot, Laurent; Chouteau, Julien; Rollier, Jean-Charles

    2018-06-02

    While uncemented THA has proven benefits over cemented THA, the use of uncemented components in the elderly remains controversial. The purpose of this study was to compare functional outcomes and complication rates of uncemented THA in patients aged > 80 to patients aged < 80, and determine factors that independently influence functional outcomes. The authors evaluated 411 consecutive uncemented THAs at a follow-up of 3.1 ± 0.9 years (range 1.8-5.2), using the Oxford hip score (OHS), EuroQol 5 Dimensions (EQ-5D) score, and noting any complications. The series was divided into two age groups: elderly group (> 80, n = 142) and control group (< 80, n = 269). Uni- and multi-variable regressions were performed to test associations between outcomes and patient age, BMI, American Society of Anaesthesiologists (ASA) score, canal bone ratio (CBR) and canal flare index (CFI). The elderly group had femora with higher CBR (p < 0.001) and lower CFI (p = 0.002). The clinical scores were significantly worse for the elderly group, with a higher OHS (p = 0.039) and a lower EQ-5D score (p = 0.009), but there were no significant differences in overall complications rates (p = 0.500). Periprosthetic fractures were observed in three elderly patients (2.1%), compared to none of the younger patients (p = 0.041). Multi-variable regressions revealed that OHS was not correlated with any of the variables, while EQ-5D score was significantly associated with BMI (p = 0.015), ASA score (p = 0.024) and CBR (p = 0.019). Clinical outcomes of uncemented THA do not depend on patient age per se, but on more specific preoperative characteristics such as ASA score, BMI and bone quality/morphology.

  14. High proximal migration in cemented acetabular revisions operated with bone impaction grafting; 47 revision cups followed with RSA for 17 years.

    PubMed

    Mohaddes, Maziar; Herberts, Peter; Malchau, Henrik; Johanson, Per-Erik; Kärrholm, Johan

    2017-05-12

    Bone impaction grafting is a biologically and mechanically appealing option in acetabular revision surgery, allowing restitution of the bone stock and restoration of the biomechanics. We analysed differences in proximal migration of the revision acetabular components when bone impaction grafting is used together with a cemented or an uncemented cup. 43 patients (47 hips), revised due to acetabular loosening and judged to have less than 50% host bone-implant contact were included. The hips were randomised to either an uncemented (n = 20) or a cemented (n = 27) revision cup. Radiostereometry and radiography was performed postoperatively, at 3 and 6 months, 1, 2, 3, 5, 7, 10 and 13 and 17 years postoperatively. Clinical follow-up was performed at 1, 2 and 5 years postoperatively and thereafter at the same interval as in the radiographic follow-up. There were no differences in the base line demographic data between the 2 groups. At the last follow-up (17 years) 14 hips (10 cemented, 4 uncemented) had been re-revised due to loosening. 3 additional cups (1 uncemented and 2 cemented) were radiographically loose. There was a higher early proximal migration in the cemented cups. Cups operated on with cement showed a higher early migration measured with RSA and also a higher number of late revisions. The reason for this is not known, but factors such as inclusion of cases with severe bone defects, use of smaller bone chips and issues related to the impaction technique might have had various degrees of influence.

  15. 21 CFR 888.3340 - Hip joint metal/composite semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint metal/composite semi-constrained cemented prosthesis. 888.3340 Section 888.3340 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Hip joint metal/composite semi-constrained cemented prosthesis. (a) Identification. A hip joint metal...

  16. 21 CFR 888.3340 - Hip joint metal/composite semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/composite semi-constrained... Hip joint metal/composite semi-constrained cemented prosthesis. (a) Identification. A hip joint metal/composite semi-constrained cemented prosthesis is a two-part device intended to be implanted to replace a...

  17. 21 CFR 888.3400 - Hip joint femoral (hemi-hip) metallic resurfacing prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint femoral (hemi-hip) metallic resurfacing... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3400 Hip joint femoral (hemi-hip) metallic resurfacing prosthesis. (a) Identification. A hip joint femoral (hemi-hip...

  18. 21 CFR 888.3370 - Hip joint (hemi-hip) acetabular metal cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint (hemi-hip) acetabular metal cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3370 Hip joint (hemi-hip) acetabular metal cemented prosthesis. (a) Identification. A hip joint (hemi-hip) acetabular...

  19. Nerve injury after hip arthroplasty. 5/600 cases after uncemented hip replacement, anterolateral approach versus direct lateral approach.

    PubMed

    van der Linde, M J; Tonino, A J

    1997-12-01

    In 600 consecutive uncemented total hip replacements, 2 surgical approaches were used: the direct lateral Hardinge approach in supine position (group I: 241 cases) or in a lateral position (group II: 280 cases) and the anterolateral Watson-Jones approach in supine position (group III: 79 cases). 5 patients had clinically evident peripheral nerve injuries confirmed with EMG: none in group I, 1 lesion of the nervus ischiadicus and nervus femoralis in group II and 4 nervus femoralis lesions in group III, of which 1 was combined with an obturator nerve injury. The nerve injuries were evaluated with EMG. All 4 nervus femoralis lesions recovered spontaneously, but the one patients in group II had a persistent palsy of the peroneal nerve. The anatomical basis for the higher prevalence of nervus femoralis lesions in the anterolateral Watson-Jones approach is described.

  20. Uncemented three-dimensional-printed prosthetic reconstruction for massive bone defects of the proximal tibia.

    PubMed

    Lu, Minxun; Li, Yongjiang; Luo, Yi; Zhang, Wenli; Zhou, Yong; Tu, Chongqi

    2018-03-06

    Currently, it is challenging to treat massive bone defects of proximal tibia. Although numerous methods are available for reconstruction with epiphysis preservation, limitations in knee function and complications are noted with these methods. Our paper describes our attempt to reconstruct a marked defect in the proximal tibia with an uncemented three-dimensional (3D)-printed prosthesis and to evaluate the prosthesis design and short-term outcomes. A 15-year-old boy with metaphyseal osteosarcoma of the tibia underwent intercalary allograft reconstruction following wide tumour resection with epiphysis preservation. However, chronic allograft rejection and/or infection occurred after the surgery and a sinus tract was formed. The rejection and/or infection process was successfully stopped by the removal of the graft and implantation of an antibiotic-loaded cement spacer; however, the limb function was poor. Because of the irregular shape of the defect and the excessively short length of the residual proximal tibia, we used the 3D printing technology to design and fabricate a personalised prosthesis to reconstruct the defect, with the preservation of the knee joint. At the last follow-up at 26 months, the patient had satisfactory limb function. The 3D-printed prosthesis may be a feasible option in the reconstruction of tibial metaphyseal defects with the preservation of the knee joint. Moreover, it can result in good postoperative function and low complication rates. However, a long-term follow-up is required to clarify its long-term outcomes.

  1. Hip Resurfacing: An Alternative to Conventional Hip Replacement?

    MedlinePlus

    ... and capped with a metal prosthesis. The hip socket is fitted with a metal cup. As these ... problem, but higher levels may be problematic. The socket prosthesis for a traditional hip replacement is usually ...

  2. 21 CFR 888.3350 - Hip joint metal/polymer semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint metal/polymer semi-constrained cemented prosthesis. 888.3350 Section 888.3350 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... metal/polymer semi-constrained cemented prosthesis. (a) Identification. A hip joint metal/polymer semi...

  3. 21 CFR 888.3350 - Hip joint metal/polymer semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/polymer semi-constrained cemented prosthesis. 888.3350 Section 888.3350 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... metal/polymer semi-constrained cemented prosthesis. (a) Identification. A hip joint metal/polymer semi...

  4. 21 CFR 888.3350 - Hip joint metal/polymer semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hip joint metal/polymer semi-constrained cemented prosthesis. 888.3350 Section 888.3350 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... metal/polymer semi-constrained cemented prosthesis. (a) Identification. A hip joint metal/polymer semi...

  5. 21 CFR 888.3350 - Hip joint metal/polymer semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hip joint metal/polymer semi-constrained cemented prosthesis. 888.3350 Section 888.3350 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... metal/polymer semi-constrained cemented prosthesis. (a) Identification. A hip joint metal/polymer semi...

  6. 21 CFR 888.3350 - Hip joint metal/polymer semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hip joint metal/polymer semi-constrained cemented prosthesis. 888.3350 Section 888.3350 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... metal/polymer semi-constrained cemented prosthesis. (a) Identification. A hip joint metal/polymer semi...

  7. 21 CFR 888.3565 - Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... type of device is designed to achieve biological fixation to bone without the use of bone cement. This... bearing is rigidly secured to the metal tibial base plate. (b) Classification. Class II (special controls). The special control is FDA's guidance: “Class II Special Controls Guidance Document: Knee Joint...

  8. 21 CFR 888.3400 - Hip joint femoral (hemi-hip) metallic resurfacing prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hip joint femoral (hemi-hip) metallic resurfacing prosthesis. 888.3400 Section 888.3400 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3400 Hip joint...

  9. 21 CFR 888.3370 - Hip joint (hemi-hip) acetabular metal cemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hip joint (hemi-hip) acetabular metal cemented prosthesis. 888.3370 Section 888.3370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3370 Hip joint...

  10. 21 CFR 888.3400 - Hip joint femoral (hemi-hip) metallic resurfacing prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hip joint femoral (hemi-hip) metallic resurfacing prosthesis. 888.3400 Section 888.3400 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3400 Hip joint...

  11. 21 CFR 888.3370 - Hip joint (hemi-hip) acetabular metal cemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hip joint (hemi-hip) acetabular metal cemented prosthesis. 888.3370 Section 888.3370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3370 Hip joint...

  12. 21 CFR 888.3370 - Hip joint (hemi-hip) acetabular metal cemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hip joint (hemi-hip) acetabular metal cemented prosthesis. 888.3370 Section 888.3370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3370 Hip joint...

  13. 21 CFR 888.3400 - Hip joint femoral (hemi-hip) metallic resurfacing prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hip joint femoral (hemi-hip) metallic resurfacing prosthesis. 888.3400 Section 888.3400 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3400 Hip joint...

  14. 21 CFR 888.3400 - Hip joint femoral (hemi-hip) metallic resurfacing prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint femoral (hemi-hip) metallic resurfacing prosthesis. 888.3400 Section 888.3400 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3400 Hip joint...

  15. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Butler, W; Merrick, G; Kurko, B

    Purpose: To quantify the effect of metal hip prosthesis on the ability to track and localize electromagnetic transponders. Methods: Three Calypso transponders were implanted into two prostate phantoms. The geometric center of the transponders were identified on computed tomography and set as the isocenter. With the phantom stationary on the treatment table and the tracking array 14-cm above the isocenter, data was acquired by the Calypso system at 10 Hz to establish the uncertainty in measurements. Transponder positional data was acquired with unilateral hip prostheses of different metallic compositions and then with bilateral hips placed at variable separation from themore » phantom. Results: Regardless of hip prosthesis composition, the average vector displacement in the presence of a unilateral prosthesis was < 0.5 mm. The greatest contribution to overall vector displacement occurred in the lateral dimension. With bilateral hip prosthesis, the average vector displacement was 0.3 mm. The displacement in the lateral dimension was markedly reduced compared with a unilateral hip, suggesting that there was a countervailing effect with bilateral hip prosthesis. The greatest average vector displacement was 0.6 mm and occurred when bilateral hip prostheses were placed within 4 cm of the detector array. Conclusion: Unilateral and bilateral hip prostheses did not have any meaningful effect on the ability to accurately track electromagnetic transponders implanted in a prostate phantom. At clinically realistic distances between the hip and detection array, the average tracking error is negligible.« less

  16. Total Hip Intraoperative Femur Fracture: Do the Design Enhancements of a Second-Generation Tapered-Wedge Stem Reduce the Incidence?

    PubMed

    Colacchio, Nicholas D; Robbins, Claire E; Aghazadeh, Mehran S; Talmo, Carl T; Bono, James V

    2017-10-01

    Intraoperative femur fracture (IFF) is a well-known complication in primary uncemented total hip arthroplasty (THA). Variations in implant instrumentation design and operative technique may influence the risk of IFF. This study investigates IFF between a standard uncemented tapered-wedge femoral stem and its second-generation successor with the following design changes: size-specific medial curvature, proportional incremental stem growth, modest reduction in stem length, and distal lateral relief. A single experienced surgeon's patient database was retrospectively queried for IFF occurring during primary uncemented THA using a standard tapered-wedge femoral stem system or a second-generation stem. All procedures were performed using soft tissue preserving anatomic capsule repair and posterior approach. The primary outcome measure was IFF. A z-test of proportions was performed to determine significant difference between the 2 stems with respect to IFF. Patient demographics, Dorr classification, and implant characteristics were also examined. Forty-one of 1510 patients (2.72%) who received a standard tapered-wedge femoral stem sustained an IFF, whereas 5 of 800 patients (0.63%) using the second-generation stem incurred an IFF. No other significant associations were found. A standard tapered-wedge femoral stem instrumentation system resulted in greater than 4 times higher incidence of IFF than its second-generation successor used for primary uncemented THA. Identifying risk factors for IFF is necessary to facilitate implant system improvements and thus maximize patient outcomes. Copyright © 2017. Published by Elsevier Inc.

  17. Can Patients Practice Strenuous Sports After Uncemented Ceramic-on-Ceramic Total Hip Arthroplasty?

    PubMed Central

    Bonnin, Michel P.; Rollier, Jean-Charles; Chatelet, Jean-Christophe; Ait-Si-Selmi, Tarik; Chouteau, Julien; Jacquot, Laurent; Hannink, Gerjon; Saffarini, Mo; Fessy, Michel-Henri

    2018-01-01

    Background: Patients are often concerned about returning to sports after total hip arthroplasty (THA). Purpose: To (1) evaluate sports participation and motivation rates in a large cohort of patients who underwent uncemented THA with ceramic-on-ceramic bearings and (2) determine whether patients’ participation was associated with their motivation for each sport, preoperative demographics, or patient-reported outcomes. Study Design: Case-control study; Level of evidence, 3. Methods: We surveyed 1310 patients (aged <75 years) who underwent uncemented ceramic-on-ceramic THA and collected levels of motivation and participation for 22 different sports as well as patient-reported outcome measure scores. A total of 1042 patients (1206 hips) returned questionnaires; the mean age at index surgery was 60.6 ± 8.8 years. Results: At least 51% of patients participated regularly or frequently in at least 1 light sport, 73% in at least 1 moderate sport, and 20% in at least 1 strenuous sport. Sports participation was strongly correlated with motivation (r = 0.97, P < .001) but not with level of discomfort (r = 0.22, P = .292). Participation in strenuous sports was significantly associated with age, body mass index, and sex. There were significant differences among patients who practiced various categories of sports as determined using the Oxford Hip Score (P = .008), but not with regard to the Forgotten Joint Score (P = .054). Conclusion: Only 20% of patients practiced strenuous sports regularly or frequently after THA, regardless of pain or discomfort. Participation in sports after THA is strongly correlated with motivation but not with level of discomfort. Longer term studies with a greater focus on complications and survival are necessary to determine whether high-impact sports compromise patient safety or implant longevity. PMID:29707594

  18. 21 CFR 888.3410 - Hip joint metal/polymer or ceramic/polymer semiconstrained resurfacing cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/polymer or ceramic/polymer... Devices § 888.3410 Hip joint metal/polymer or ceramic/polymer semiconstrained resurfacing cemented prosthesis. (a) Identification. A hip joint metal/polymer or ceramic/polymer semi-constrained resurfacing...

  19. 21 CFR 888.3410 - Hip joint metal/polymer or ceramic/polymer semiconstrained resurfacing cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint metal/polymer or ceramic/polymer... Devices § 888.3410 Hip joint metal/polymer or ceramic/polymer semiconstrained resurfacing cemented prosthesis. (a) Identification. A hip joint metal/polymer or ceramic/polymer semi-constrained resurfacing...

  20. 21 CFR 888.3410 - Hip joint metal/polymer or ceramic/polymer semiconstrained resurfacing cemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hip joint metal/polymer or ceramic/polymer... Devices § 888.3410 Hip joint metal/polymer or ceramic/polymer semiconstrained resurfacing cemented prosthesis. (a) Identification. A hip joint metal/polymer or ceramic/polymer semi-constrained resurfacing...

  1. 21 CFR 888.3410 - Hip joint metal/polymer or ceramic/polymer semiconstrained resurfacing cemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hip joint metal/polymer or ceramic/polymer... Devices § 888.3410 Hip joint metal/polymer or ceramic/polymer semiconstrained resurfacing cemented prosthesis. (a) Identification. A hip joint metal/polymer or ceramic/polymer semi-constrained resurfacing...

  2. 21 CFR 888.3410 - Hip joint metal/polymer or ceramic/polymer semiconstrained resurfacing cemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hip joint metal/polymer or ceramic/polymer... Devices § 888.3410 Hip joint metal/polymer or ceramic/polymer semiconstrained resurfacing cemented prosthesis. (a) Identification. A hip joint metal/polymer or ceramic/polymer semi-constrained resurfacing...

  3. The influence of implant design on periprosthetic bone remodelling of two types of uncemented HA-coated hip stems. A two-year follow-up study using DEXA.

    PubMed

    Van der Wal, B C H; Rahmy, A I A; Grimm, B; Blake, G M; Heyligers, I C; Tonino, A J

    2006-01-01

    Proximal bone resorption and an increased fracture rate in the ABG-I stem has been shown. For these reasons the ABG-I stem design was changed to the ABG-II. In this study periprosthetic bone loss around the ABG-I vs ABG-II is compared to verify if the design changes resulted in improved proximal bone preservation. 51 patients were randomised to either the ABG-I or ABG-II hip prosthesis. Periprosthetic BMD change at various time points was measured using DEXA. Between the two groups (age, gender, weight etc.) no statistical difference was encountered. Compared to the baseline at two years the ABG-II preserved bone better proximally (e.g. zone 7: ABG-II: -3.7%, ABG-I: -11.9%, p=0.05) than the ABG-I. Distally, the trend was opposite and less bone loss was measured for the ABG-I than the ABG-II in zones 3, 4 and 5 (n.s.). this study confirms the philosophy behind the design changes from the ABG-I to ABG-II stem where increased elasticity, more proximal HA-coating, a shorter and distally polished stem, were meant to reduce proximal bone resorption. In future this may lead to fewer periprosthetic fractures and to less complicated revision surgery.

  4. Greater inadvertent muscle damage in direct anterior approach when compared with the direct superior approach for total hip arthroplasty.

    PubMed

    Amanatullah, D F; Masini, M A; Roger, D J; Pagnano, M W

    2016-08-01

    We wished to quantify the extent of soft-tissue damage sustained during minimally invasive total hip arthroplasty through the direct anterior (DA) and direct superior (DS) approaches. In eight cadavers, the DA approach was performed on one side, and the DS approach on the other, a single brand of uncemented hip prosthesis was implanted by two surgeons, considered expert in their surgical approaches. Subsequent reflection of the gluteus maximus allowed the extent of muscle and tendon damage to be measured and the percentage damage to each anatomical structure to be calculated. The DA approach caused substantially greater damage to the gluteus minimus muscle and tendon when compared with the DS approach (t-test, p = 0.049 and 0.003, respectively). The tensor fascia lata and rectus femoris muscles were damaged only in the DA approach. There was no difference in the amount of damage to the gluteus medius muscle and tendon, piriformis tendon, obturator internus tendon, obturator externus tendon or quadratus femoris muscle between approaches. The posterior soft-tissue releases of the DA approach damaged the gluteus minimus muscle and tendon, piriformis tendon and obturator internus tendon. The DS approach caused less soft-tissue damage than the DA approach. However the clinical relevance is unknown. Further clinical outcome studies, radiographic evaluation of component position, gait analyses and serum biomarker levels are necessary to evaluate and corroborate the safety and efficacy of the DS approach. Cite this article: Bone Joint J 2016;98-B1036-42. ©2016 The British Editorial Society of Bone & Joint Surgery.

  5. Screws are not needed when secure interference fit of uncemented acetabular components is adequate: a 5- to 15-year follow-up with clinical and radiological analysis.

    PubMed

    García-Rey, Eduardo

    2017-05-12

    Even with good surgical preparation, adequate primary stability of the acetabular component is not always achieved after primary total hip replacement (THR). We hypothesise that adequate bone preparation for appropriate cortical loading would allow us to avoid screw use. A total of 791 uncemented cups were analysed to compare the need for screws to obtain primary fixation in 5 different designs. Arthritic hips with inflammatory arthritis or severe congenital hip disease were excluded. A press-fit technique was first tried in all hips and screws were only used when strictly needed. Radiological acetabular shape and postoperative cup position were assessed in all hips. The mean follow-up was 9.6 (5-15) years. Screws were required in 155 hips (19.6%). We could not detect any difference in the percentage of screw use between designs. We found that female patients (odds ratio [OR] 2.06; 95% confidence interval [CI], 1.41-3.02) and cups with a greater distance to the hip rotation centre on the postoperative radiograph (OR 1.69; 95% CI, 1.17-2.45) had a higher risk for screw use. A greater anteversion of the cup had a lower risk for screw use (OR 0.96; 95% CI, 0.94-0.99). At latest follow-up no hips had needed revision for aseptic loosening. Good intraoperative technique is not enough to avoid screw use since more accurate cup position and reconstruction of the hip rotation centre are required for an adequate interference fit. A press-fit technique can provide similar mid-term results to screw use in hips without severe deformities.

  6. 21 CFR 888.3320 - Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/metal semi-constrained, with a... Devices § 888.3320 Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with a cemented acetabular...

  7. 21 CFR 888.3320 - Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint metal/metal semi-constrained, with a... Devices § 888.3320 Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with a cemented acetabular...

  8. Hydroxyapatite clay for gap filling and adequate bone ingrowth.

    PubMed

    Maruyama, M; Terayama, K; Ito, M; Takei, T; Kitagawa, E

    1995-03-01

    In uncemented total hip arthroplasty, a complete filling of the gap between femoral prosthesis and the host bone is difficult and defects would remain, because the anatomy of the reamed intramedullary canal cannot fit the prosthesis. Therefore, it seems practical to fill the gap with a clay containing hydroxyapatite (HA), which has an osteoconductive character. The clay (HA clay) is made by mixing HA granules (size 0.1 mm or more) having a homogeneous pore distribution and a porosity of 35-48 vol%, and a viscous substance such as a saline solution of sodium alginate (SSSA). In the first experiment, the ratio of HA granules and sodium alginate in SSSA is set for the same handling properties of HA clay and polymethylmethacrylate bone cement (standard viscosity) before hardening. As a result, the ratio is set for 55 wt% of HA in the clay and 12.5 wt% of sodium alginate in SSSA (i.e., HA:sodium alginate:saline solution = 9.8:1:7). In the second study, the gap between the femoral stem and bone model is completely filled with HA clay. However, the gap is not filled only with HA granules or HA granules mixed with saline solution. In the third animal experiment, using an unloaded model, histology shows that HA clay has an osteoconductive property bridging the gap between the implant and the cortical bone without any adverse reaction. HA clay is considered a useful biomaterial to fill the gap with adequate bone ingrowth.

  9. Risk Factors for Periacetabular Osteolysis and Wear in Asymptomatic Patients with Uncemented Total Hip Arthroplasties

    PubMed Central

    Olivecrona, Henrik; Garellick, Göran

    2014-01-01

    Osteolysis is a silent disease leading to aseptic loosening. This has not been studied in a cohort of asymptomatic patients. The aim of this study was to detect factors that might be associated with the development of periacetabular osteolysis and wear around an uncemented cup. We assessed 206 patients with an uncemented cup, measuring wear and periacetabular osteolysis using computed tomography with a median follow-up of 10 years after surgery (range 7–14 years). EQ5D, pain from the hip, and satisfaction were assessed. The association between periacetabular osteolysis and wear, age, gender, activity, BMI, cup type, cup age, positioning of the cup, and surface coating was investigated with a proportional odds model. Wear and male gender were associated with an increased risk for periacetabular osteolysis. There was no association with periacetabular osteolysis for time from operation, patient age, UCLA Activity Score, liner thickness at time of operation, BMI, cup positioning, and type of implant. A thin liner at time of operation is correlated to increased wear. Linear wear rate was 0.18 mm/year and 46 of 206 patients had large periacetabular osteolysis. Asymptomatic patients with these implants should be followed up on a regular basis with a sensitive method such as CT in order to detect complications early. PMID:25478600

  10. Avascular necrosis of the femoral head at 2 years after pertrochanteric fracture surgery: Case report.

    PubMed

    Deleanu, Bogdan; Prejbeanu, Radu; Vermesan, Dinu; Honcea, Lucian; Mioc, Mihail Lazar; Tsiridis, Eleftherios; Predescu, Vlad

    2016-02-01

    The avascular necrosis of the femoral head represents the death of bone tissue due to the lack of blood supply. The disease has a progressive evolution and left untreated leads to femoral head collapse and severe arthritis. We present a case of a pertrochanteric fracture which has been successfully operated with a dynamic interlocking trochanteric gamma nail on the right hip. At 2 years after surgery the patient developed an incipient avascular necrosis of the femoral head. Despite the good positioning of the implant, we considered that the source of the pain was an intolerance of the implant, and thus we removed it. After implant removal, the patient was kept under observation and conservative treatment, to prevent further damage to the right hip and allow the healing to occur. At 6 months after the gamma nail was removed the X-rays revealed advanced avascular necrosis of the femoral head and secondary osteoarthritis on the right hip. The patient underwent surgery with an uncemented total hip arthroplasty. There are a few discussions regarding the avascular necrosis of the femoral head. These discussions may include the predisposing risk factors, the treatment of choice and the postoperative complications. The avascular necrosis of the femoral head is a complication of pertrochanteric fractures that can not be foreseen or avoided. The optimal treatment in these cases is uncemented total hip arthroplasty.

  11. Key Parameters Evaluation for Hip Prosthesis with Finite Element Analysis

    NASA Astrophysics Data System (ADS)

    Guo, Hongqiang; Li, Dichen; Lian, Qin; Li, Xiang; Jin, Zhongmin

    2007-09-01

    Stem length and cross section are two key parameters that influence the stability and longevity of metallic hip prosthesis in the total hip arthroplasty (THA). In order to assess their influence to the stress and fatigue behavior of hip prosthesis, a series model of hip prosthesis with round-shaped or drum-shaped cross section, and with different stem lengths were created. These models were analyzed under both static and dynamic loading conditions with finite element analysis, and dynamic loading represents normal walking was used in the dynamic analysis. The stress on the metallic stem, cement, and adjacent bone were got, micromotion on the cement-metal interface were got too. Safety factors for fatigue life of the hip prothesis were calculated based on data obtained from dynamic analysis. Static analysis shows that drum-shaped cross section can decrease the displacement of the stem, that stress on drum-shaped stem focus on the corner of the femoral neck and the distal part of hip prosthesis, whereas the stress on the round-shaped stem distributes evenly over most part of the stem, and maximum stress on stem prosthesis fluctuates with stem length bottoming out at stem length range from 80 mm to 110 mm, that drum-shaped stems with drum height 8 mm generate more stress at the distal part of stem than drum-shaped stems with drum height 10 mm and round stems do. Dynamic and fatigue analysis shows that drum-shaped stem with drum height 10 mm and stem length 90 mm has the greatest safety factor therefore long fatigue life.

  12. The Corail stem as a reverse hybrid - survivorship and x-ray analysis at 10 years.

    PubMed

    Wangen, Helge; Nordsletten, Lars; Boldt, Jens G; Fenstad, Anne M; Beverland, David E

    2017-07-25

    The use of a cemented cup together with an uncemented stem in total hip arthroplasty (THA) has become popular in Norway and Sweden during the last decade. The results of this prosthetic concept, reverse hybrid THA have been sparsely described.We report our experience of reverse hybrid THA, using the Elite plus polyethylene cemented cup together with the Corail fully hydroxyapatite-coated uncemented stem and a 28-mm alumina ceramic head. 132 consecutive reverse hybrid hip arthroplasties were performed from January 2000 to December 2003 in 126 patients with a mean age of 54.3 years (28-65). All patients were routinely reviewed at 3 months, 1, 5, 7 and 10 years postoperatively. At each follow-up patients were seen either by a consultant orthopaedic surgeon or a senior trainee. Anteroposterior pelvic and lateral x-rays of the hip were taken at each visit. To estimate the survival of the THAs we used the Kaplan-Meier method with 95% confidence interval (CI). Logistic regression analysis was performed to determine which factors affected the presence of radiolucency around the femoral stem. The mean follow-up was 11.1 years (9.0-14.2). 1 patient was lost to follow-up, and 7 patients were deceased at the time of 10-year follow up. At 10 years 7 patients have had further surgery. 5 for infection, 1 periprosthetic femoral fracture and 1 heterotopic bone formation. All stems were classified as well fixed. 2 cups were defined as loose at 10 years. 1 patient is scheduled for revision the other refused revision. The clinical outcome and radiological findings were assessed in 123 hips. The mean Harris Hip Score was 94 (35-100) at 10 years and the mean WOMAC score was 89 (30.2-100). We report good results with respect to clinical outcome and survival of the reverse hybrid concept in patients younger than 65. A successful outcome depends on meticulous preoperative planning, use of modern cementing techniques in the acetabulum and experience in implanting an uncemented stem.

  13. Clinical accuracy of a patient-specific femoral osteotomy guide in minimally-invasive posterior hip arthroplasty.

    PubMed

    Schneider, Adrian K; Pierrepont, Jim W; Hawdon, Gabrielle; McMahon, Stephen

    2018-04-01

    Patient specific guides can be a valuable tool in improving the precision of planned femoral neck osteotomies, especially in minimally invasive hip surgery, where bony landmarks are often inaccessible. The aim of our study was to validate the accuracy of a novel patient specific femoral osteotomy guide for THR through a minimally invasive posterior approach, the direct superior approach (DSA). As part of our routine preoperative planning 30 patients underwent low dose CT scans of their arthritic hip. 3D printed patient specific femoral neck osteotomy guides were then produced. Intraoperatively, having cleared all soft tissue from the postero-lateral neck of the enlocated hip, the guide was placed and pinned onto the posterolateral femoral neck. The osteotomy was performed using an oscillating saw and the uncemented hip components were implanted as per routine. Postoperatively, the achieved level of the osteotomy at the medial calcar was compared with the planned level of resection using a 3D/2D matching analysis (Mimics X-ray module, Materialise, Belgium). A total of 30 patients undergoing uncemented Trinity™ acetabular and TriFit TS™ femoral component arthroplasty (Corin, UK) were included in our analysis. All but one of our analysed osteotomies were found to be within 3 mm from the planned height of osteotomy. In one patient the level of osteotomy deviated 5 mm below the planned level of resection. Preoperative planning and the use of patient specific osteotomy guides provides an accurate method of performing femoral neck osteotomies in minimally invasive hip arthroplasty using the direct superior approach. IV (Case series).

  14. Cup press fit in uncemented THA depends on sex, acetabular shape, and surgical technique.

    PubMed

    García-Rey, Eduardo; García-Cimbrelo, Eduardo; Cruz-Pardos, Ana

    2012-11-01

    Uncemented press-fit cups provide bone fixation in primary THA, but the use of screws is sometimes necessary to achieve primary stability of the socket. However, it is unclear whether and when screws should be used. We analyzed the factors related to screw use with a press-fit uncemented cup and assessed whether screw use is associated with the same rates of loosening and revision as a press-fit technique. We retrospectively reviewed 248 patients who underwent THA using the same prosthetic design. Eighty-eight hips had screws to achieve primary cup fixation (Group 1), and 189 did not (Group 2). Mean age was 50 years (range, 14-73 years). We analyzed factors related to the patient, acetabular type, and reconstruction of the rotation center of the hip. Minimum followup was 5 years (mean, 8.9 years; range, 5-12 years). We found higher screw use in women, patients with less physical activity, Acetabular Types A or C, and a distance from the center of the prosthetic femoral head to the normal center of rotation of more than 3 mm. There were four revisions in Group 1 and five in Group 2. Eight hips had radiographic loosening in Group 1 and nine in Group 2. Cups with a postoperative abduction angle of more than 50° had a higher risk for loosening. Press fit was achieved less frequently in women and patients with Acetabular Types A or C and less physical activity; a closer distance to the normal center of rotation decreased screw use. Screw use to augment fixation achieved survival similar to that of a press-fit cup. Level II, prognostic study. See Instructions for Authors for a complete description of levels of evidence.

  15. Does oversizing an uncemented cup increase post-operative pain in primary total hip arthroplasty?

    PubMed

    Barrow, Jonathan A; Divecha, Hiren M; Panchani, Sunil; Boden, Richard; Porter, Martyn L; Board, Tim N

    2018-05-31

    It has been suggested that one of the factors related to persistent post-operative pain following total hip arthroplasty (THA) is to over sizing of the acetabular component. In order to investigate this potential issue, we retrospectively analysed a series of consecutive uncemented THA. We assessed the incidence of persistent post-operative pain and the size difference between the implanted acetabular component and the native femoral head. A total of 265 consecutive THAs were retrospectively identified. Standardised pre-operative radiographs were analysed using validated techniques to determine the native femoral head diameter. Post-operative standardised radiographs were reviewed and the acetabular orientation determined. Patients were sent postal questionnaires regarding their outcome and level of pain. Questionnaires were returned by 169 patients (189 hips, 71% response rate). A total of 17 were excluded due to inadequate radiographs., leaving 172 THA in the study group. The mean native femoral head (NFH) size was 47 mm. The most common implanted acetabular component size was 52 mm. The mean difference in cup to NFH diameter (delta) was 5.7 mm (range - 6.1 to 15.4 mm; 95% CI 5.3-6.2 mm). A delta of > 6 mm was found to be significant for predicting persistent post-operative pain (RR = 1.81; 95% CI 1.1-3.1; P = 0.027). Our study confirms that a delta of > 6 mm is associated with an increased risk of persistent post-operative pain following THA. We recommend pre-operative templating in all uncemented THA to ensure the planned acetabular component is no more than 6 mm larger than the NFH diameter.

  16. Early follow-up of a custom non-fluted diaphyseal press-fit tumour prosthesis.

    PubMed

    O'Donnell, Patrick W; Griffin, Anthony M; Eward, William C; Sternheim, Amir; Wunder, Jay S; Ferguson, Peter C

    2014-01-01

    The objective of this study was to evaluate the early results of a custom non-fluted diaphyseal press-fit stem for use with the global modular replacement system (GMRS) tumour prosthesis and the early complications associated with this implant. A total of 53 patients (54 implants) were identified from a prospective database where a custom non-fluted diaphyseal press-fit stem was used as part of the reconstruction of the limb. All patients had a minimum of 22 months of follow-up. The rates of stem revision for any reason were calculated. The median follow-up was 36 months (range 22-85 months). Aseptic loosening was not observed in any patient. At early term follow-up, an uncemented non-fluted stem used with the GMRS tumour endoprosthesis provides a stable bone-prosthesis interface with no evidence of aseptic loosening.

  17. Computed tomography vs. digital radiography assessment for detection of osteolysis in asymptomatic patients with uncemented cups: a proposal for a new classification system based on computer tomography.

    PubMed

    Sandgren, Buster; Crafoord, Joakim; Garellick, Göran; Carlsson, Lars; Weidenhielm, Lars; Olivecrona, Henrik

    2013-10-01

    Digital radiographic images in the anterior-posterior and lateral view have been gold standard for evaluation of peri-acetabular osteolysis for patients with an uncemented hip replacement. We compared digital radiographic images and computer tomography in detection of peri-acetabular osteolysis and devised a classification system based on computer tomography. Digital radiographs were compared with computer tomography on 206 hips, with a mean follow up 10 years after surgery. The patients had no clinical signs of osteolysis and none were planned for revision surgery. On digital radiographs, 192 cases had no osteolysis and only 14 cases had osteolysis. When using computer tomography there were 184 cases showing small or large osteolysis and only 22 patients had no osteolysis. A classification system for peri-acetabular osteolysis is proposed based on computer tomography that is easy to use on standard follow up evaluation. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Custom hip prostheses by integrating CAD and casting technology

    NASA Astrophysics Data System (ADS)

    Silva, Pedro F.; Leal, Nuno; Neto, Rui J.; Lino, F. Jorge; Reis, Ana

    2012-09-01

    Total Hip Arthroplasty (THA) is a surgical intervention that is being achieving high rates of success, leaving room to research on long run durability, patient comfort and costs reduction. Even so, up to the present, little research has been done to improve the method of manufacturing customized prosthesis. The common customized prostheses are made by full machining. This document presents a different approach methodology which combines the study of medical images, through CAD (Computer Aided Design) software, SLadditive manufacturing, ceramic shell manufacture, precision foundry with Titanium alloys and Computer Aided Manufacturing (CAM). The goal is to achieve the best comfort for the patient, stress distribution and the maximum lifetime of the prosthesis produced by this integrated methodology. The way to achieve this desiderate is to make custom hip prosthesis which are adapted to each patient needs and natural physiognomy. Not only the process is reliable, but also represents a cost reduction comparing to the conventional full machined custom hip prosthesis.

  19. Medium to long-term results of the UNIX uncemented unicompartmental knee replacement.

    PubMed

    Hall, Matthew J; Connell, David A; Morris, Hayden G

    2013-10-01

    We report the first non-designer study of the Unix uncemented unicompartmental knee prosthesis. Eighty-five consecutive UKRs were carried out with sixty-five available for follow-up. Oxford Knee Scores, WOMAC questionnaire and radiological assessment were completed. The mean Oxford Knee Score was thirty-eight and WOMAC Score was twenty. Overall Kaplan Meier survival estimate is 76% (95% confidence interval 60%-97%) at 12years and 88% (95% confidence interval 76-100%) with aseptic loosening as the endpoint. Radiographic assessment showed lysis in the tibia in 6% of patients with no lysis evident around the central fin. Survivorship is comparable to other published series of UKRs. We suggest the central fin design is key to dissipating large forces throughout the proximal tibia, resulting in low levels of tibial loosening. Level of evidence IV. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Monte Carlo calculations of the impact of a hip prosthesis on the dose distribution

    NASA Astrophysics Data System (ADS)

    Buffard, Edwige; Gschwind, Régine; Makovicka, Libor; David, Céline

    2006-09-01

    Because of the ageing of the population, an increasing number of patients with hip prostheses are undergoing pelvic irradiation. Treatment planning systems (TPS) currently available are not always able to accurately predict the dose distribution around such implants. In fact, only Monte Carlo simulation has the ability to precisely calculate the impact of a hip prosthesis during radiotherapeutic treatment. Monte Carlo phantoms were developed to evaluate the dose perturbations during pelvic irradiation. A first model, constructed with the DOSXYZnrc usercode, was elaborated to determine the dose increase at the tissue-metal interface as well as the impact of the material coating the prosthesis. Next, CT-based phantoms were prepared, using the usercode CTCreate, to estimate the influence of the geometry and the composition of such implants on the beam attenuation. Thanks to a program that we developed, the study was carried out with CT-based phantoms containing a hip prosthesis without metal artefacts. Therefore, anthropomorphic phantoms allowed better definition of both patient anatomy and the hip prosthesis in order to better reproduce the clinical conditions of pelvic irradiation. The Monte Carlo results revealed the impact of certain coatings such as PMMA on dose enhancement at the tissue-metal interface. Monte Carlo calculations in CT-based phantoms highlighted the marked influence of the implant's composition, its geometry as well as its position within the beam on dose distribution.

  1. Vanadium release in whole blood, serum and urine of patients implanted with a titanium alloy hip prosthesis.

    PubMed

    Catalani, S; Stea, S; Beraudi, A; Gilberti, M E; Bordini, B; Toni, A; Apostoli, P

    2013-08-01

    Vanadium (V) is a minor constituent of the Titanium-Aluminum-Vanadium (TiAlV) alloy currently used in cementless hip prostheses. Present study aimed at verifying the correlation of vanadium levels among different matrices and assessing reference levels of the ion in a population of patients wearing a well-functioning hip prosthesis. Vanadium was measured using Inductive Coupled Plasma Mass Spectrometry (ICP-MS) in whole blood, serum and urine of 129 patients implanted with a TiAlV-alloy hip prosthesis. The values in the serum were above the upper limit of the reference values in 42% of patients (29% in urine and 13% in whole blood). A good correlation among matrices was observed (p < 0.001). The cohort of patients (N = 32) complaining of pain or in which a loosening or damage to the prosthesis was assessed showed a significantly higher excretion of vanadium in urine as compared with the remaining asymptomatic patients (p = 0.001). The 95th percentile distribution of vanadium in the cohort of patients with a well-functioning prosthesis was 0.3 μg/L in whole blood, 0.5 μg/L in serum and 2.8 μg/L in urine, higher that in the unexposed population, especially for urine. The presence of a prosthesis, even though well-functioning, may cause a possible release of vanadium into the blood and a significant urinary excretion. The reference values of vanadium of the asymptomatic patients with titanium alloy hip prostheses supplied information regarding the background exposure level of the ions and their lower and upper limits.

  2. Enhanced lubricant film formation through micro-dimpled hard-on-hard artificial hip joint: An in-situ observation of dimple shape effects.

    PubMed

    Choudhury, Dipankar; Rebenda, David; Sasaki, Shinya; Hekrle, Pavel; Vrbka, Martin; Zou, Min

    2018-05-01

    This study evaluates the impact of dimple shapes on lubricant film formation in artificial hip joints. Micro-dimples with 20-50 µm lateral size and 1 ± 0.2 µm depths were fabricated on CrCoMo hip joint femoral heads using a picosecond laser. Tribological studies were performed using a pendulum hip joint simulator to apply continuous swing flexion-extension motions. The results revealed a significantly enhanced lubricant film thickness (≥ 500 nm) with micro-dimpled prosthesis heads at equilibrium position after the lubricant film has fully developed. The average lubricant film thickness of dimpled prostheses with square- and triangular-shaped dimple arrays over time is about 3.5 that of the non-dimpled prosthesis (204 nm). Remarkably, the prosthesis with square-shaped dimple arrays showed a very fast lubricant film formation reaching their peak values within 0.5 s of pendulum movement, followed by prosthesis with triangular-shaped dimple arrays with a transition period of 42.4 s. The fully developed lubricant film thicknesses (≥ 700 nm) are significantly higher than the surface roughness (≈ 25 nm) demonstrating a hydrodynamic lubrication. Hardly any scratches appeared on the post-experimental prosthesis with square-shaped dimple array and only a few scratches were found on the post-experimental prosthesis with triangular-shaped dimple arrays. Thus, prostheses with square-shaped dimple arrays could be a potential solution for durable artificial hip joints. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Is reverse hybrid hip replacement the solution?

    PubMed

    Lindalen, Einar; Havelin, Leif I; Nordsletten, Lars; Dybvik, Eva; Fenstad, Anne M; Hallan, Geir; Furnes, Ove; Høvik, Oystein; Röhrl, Stephan M

    2011-12-01

    Reverse hybrid hip replacement uses a cemented all-polyethylene cup and an uncemented stem. Despite increasing use of this method in Scandinavia, there has been very little documentation of results. We have therefore analyzed the results from the Norwegian Arthroplasty Register (NAR), with up to 10 years of follow-up. The NAR has been collecting data on total hip replacement (THR) since 1987. Reverse hybrid hip replacements were used mainly from 2000. We extracted data on reverse hybrid THR from this year onward until December 31, 2009, and compared the results with those from cemented implants over the same period. Specific cup/stem combinations involving 100 cases or more were selected. In addition, only combinations that were taken into use in 2005 or earlier were included. 3,963 operations in 3,630 patients were included. We used the Kaplan-Meier method and Cox regression analysis for estimation of prosthesis survival and relative risk of revision. The main endpoint was revision for any cause, but we also performed specific analyses on different reasons for revision. We found equal survival to that from cemented THR at 5 years (cemented: 97.0% (95% CI: 96.8-97.2); reverse hybrid: 96.7% (96.0-97.4)) and at 7 years (cemented: 96.0% (95.7-96.2); reverse hybrid: 95.6% (94.4-96.7)). Adjusted relative risk of revision of the reverse hybrids was 1.1 (0.9-1.4). In patients under 60 years of age, we found similar survival of the 2 groups at 5 and 7 years, with an adjusted relative risk of revision of reverse hybrids of 0.9 (0.6-1.3) compared to cemented implants. With a follow-up of up to 10 years, reverse hybrid THRs performed well, and similarly to all-cemented THRs from the same time period. The reverse hybrid method might therefore be an alternative to all-cemented THR. Longer follow-up time is needed to evaluate whether reverse hybrid hip replacement has any advantages over all-cemented THR.

  4. The operation of the century: total hip replacement.

    PubMed

    Learmonth, Ian D; Young, Claire; Rorabeck, Cecil

    2007-10-27

    In the 1960s, total hip replacement revolutionised management of elderly patients crippled with arthritis, with very good long-term results. Today, young patients present for hip-replacement surgery hoping to restore their quality of life, which typically includes physically demanding activities. Advances in bioengineering technology have driven development of hip prostheses. Both cemented and uncemented hips can provide durable fixation. Better materials and design have allowed use of large-bore bearings, which provide an increased range of motion with enhanced stability and very low wear. Minimally invasive surgery limits soft-tissue damage and facilitates accelerated discharge and rehabilitation. Short-term objectives must not compromise long-term performance. Computer-assisted surgery will contribute to reproducible and accurate placement of implants. Universal economic constraints in healthcare services dictate that further developments in total hip replacement will be governed by their cost-effectiveness.

  5. Outcomes using wedge stem with full hydroxiapatite coverage with a minimum of 5 years' follow-up.

    PubMed

    Godoy-Monzon, D; Buttaro, M; Comba, F; Zanotti, G; Piccaluga, F; Neira-Borrajo, I

    Total Hip Arthroplsty (THA) using uncemented stems is a popular practice in the last decades. The implant survivorship is crtitical and a less than 10% revision at 10 years is been propesed for commercialization and use. To analyse the clinicoradiological results of an uncemented hydroxiapatite covered wedge stem with a 5 years minimum follow up. Prospective study, patients aged from 21-75years were included. All patients received an Element stem (Exactech) and uncemented cup with crosslink poly and 32 mm metal head, and posterior approach with piriformis retention was used. Scheduled clinical and radiographic evaluation at 3 weeks, 3-6 month, year and subsequent years using Harris Hip Score and Merle d'Aubigné Postel. Intraoperative and during follow up complications were recorded. One hundred and fourteen total hip replacements in 104 patients: 54 females and 50 males (52%/48%). Follow-up of 5.7 years (range, 5-6.2years). Average age 56.8years (range, 42-75years). Clinical evaluation the Merle d'Aubigné score improved 6.8 points and from the initianl Harris Hip Score 47.3 to 93.1 points at last follow up. Radiographic evaluation shows osteointegration in all stems. And in 6 cases (5.3% at 3 months subsidence was detected, average 1.4 mm (range 0-2.6 mm) with no clinical manifestation, 3 cases of subsidence were associated to intraoperative fractures (1 greater trochanter and 2 in the calcar area, all resolved with wire cerclaje). Subjective evaluation: 86 cases (82.6%) excellent, 9 patients (8.6%) good, 6 cases (5.9%) satisfactory and 3 cases (2.9%) poor. All poor results linked to the intraoperative complications. No patient lost during follow up period. No femoral pain dislocation or aseptic or loosening detected. All implants were in situ at last follow up. The radiological results confirm the benefits of this type of stem with good osteointegration. The clinical and subjective results are promising. With good surgical technical and without complications the risk of aseptic loosening should be absent or minimal. Copyright © 2017 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

  6. Total hip arthroplasty using a short-stem prosthesis: restoration of hip anatomy.

    PubMed

    Amenabar, Tomas; Marimuthu, Kanniraj; Hawdon, Gabrielle; Gildone, Alessandro; McMahon, Stephen

    2015-04-01

    To evaluate hip parameters such as vertical centre of rotation (VCR), horizontal centre of rotation (HCR), femoral offset, and leg length after total hip arthroplasty (THA) using the Nanos short-stem prosthesis. Medical records of 73 men and 74 women aged 25 to 92 (mean, 63) years who underwent THA using the Nanos short-stem prosthesis by a single surgeon were reviewed. Prior to the surgery, the optimal cup and stem size, head length, and level of the neck osteotomy were determined using radiographs. Intra-operatively, the leg length and femoral offset were checked, and the level of neck resection and head length were adjusted. VCR, HCR, femoral offset, and leg length of the operated and contralateral sides were compared. Functional outcomes were assessed using the Harris Hip Score (HHS). Compared with the normal contralateral hips, the operated hips had a mean increase of 0.4 mm in VCR (p=0.032), a mean decrease of 1.4 mm in HCR (p=0.027), a mean increase of 0.6 mm in femoral offset (p=0.043), and a mean increase of 0.36 mm in leg length (p=0.035). For these respective parameters, the difference between the normal contralateral side and the operated side was within 5 mm in 89%, 80%, 71%, and 96% of patients. The HHS improved from a mean of 53 to 91 at one year (p<0.001). THA using the Nanos short-stem prosthesis enabled restoration of hip anatomy (VCR, HCR, femoral offset, and leg length).

  7. 21 CFR 888.3340 - Hip joint metal/composite semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hip joint metal/composite semi-constrained cemented prosthesis. 888.3340 Section 888.3340 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3340...

  8. 21 CFR 888.3340 - Hip joint metal/composite semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hip joint metal/composite semi-constrained cemented prosthesis. 888.3340 Section 888.3340 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3340...

  9. 21 CFR 888.3340 - Hip joint metal/composite semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hip joint metal/composite semi-constrained cemented prosthesis. 888.3340 Section 888.3340 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3340...

  10. [Possibilities of follow-up imaging after implantation of a carbon fiber-reinforced hip prosthesis].

    PubMed

    Krüger, T; Alter, C; Reichel, H; Birke, A; Hein, W; Spielmann, R P

    1998-03-01

    There are many problems in the radiological diagnosis of aseptic loosening in total hip arthroplasty. Computed tomography (CT) and magnetic resonance tomography (MRT) are not usable for metallic implants (stainless steel, cobalt alloy, titanium alloy). From April 1993 to December 1993 15 CFRP non-cemented hip prostheses have been implanted. In a prospective clinical study plane radiographs, CT and MRT have been analysed. Three stems were revised (1 femoral fracture, 1 severe thigh pain, 1 aseptic loosening). CFRP are not visible in plane radiographs. There was a complete (two-third of the cases) or nearly complete (one-third of the cases) small sclerotic interface between the prosthesis and the bone, these were apparent in CT and MRT in stable implant cases and did not have any clinical correlations. The small sclerotic interface is quite different in comparison to so called "Reactive Lines". In one case of aseptic loosening there was an interposition of soft tissue between prosthesis and bone in MRT and CT. CFRP inaugurates new diagnostic possibilities in aseptic loosening of hip prosthesis and in tumour surgery too.

  11. Actinomyces gerencseriae hip prosthesis infection: a case report.

    PubMed

    Dubourg, Grégory; Delord, Marion; Gouriet, Frédérique; Fournier, Pierre-Edouard; Drancourt, Michel

    2015-09-28

    Actinomyces bacteria are part of the human oropharyngeal microbiota. They have been associated with abdominal, cervicofacial and thoracic infections and a few cases of joint infections have also been described. In particular, Actinomyces gerencseriae, formerly described as Actinomyces israelii serovar II, has rarely been associated with human infections, mostly involving cervicofacial lesions and periodontal diseases. Here, we report one case of hip prosthesis infection due to A. gerencseriae. A 72-year-old Caucasian male developed an inflammatory collection on the outside of the right thigh where a hip prosthesis had been implanted for 11 years. Culturing a fluid sample from the collection puncture found Staphylococcus hominis and a Gram-positive bacillus unidentified by matrix-assisted laser desorption ionization time-of-flight mass-spectrometry (MALDI-TOF). Sequencing the 16S rRNA gene amplified from both the specimen and the isolate identified A. gerencseriae. Treatment adjusted with amoxicillin and trimethropim-sulfamethoxazole cured the infection. The recently described A. gerencseriae has rarely been involved in human infections. We report the first case of A. gerencseriae joint infection in a hip prosthesis.

  12. Intensity-Modulated Radiation Therapy with Noncoplanar Beams for Treatment of Prostate Cancer in Patients with Bilateral Hip Prosthesis-A Case Study

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Brooks, Chris; Cheung, Rex Min; Kudchadker, Rajat J.

    2010-07-01

    Megavoltage photon intensity-modulated radiation therapy (IMRT) is typically used in the treatment of prostate cancer at our institution. Approximately 1% to 2% of patients with prostate cancer have hip prostheses. The presence of the prosthesis usually complicates the planning process because of dose perturbation around the prosthesis, radiation attenuation through the prosthesis, and the introduction of computed tomography artifacts in the planning volume. In addition, hip prostheses are typically made of materials of high atomic number, which add uncertainty to the dosimetry of the prostate and critical organs in the planning volume. When the prosthesis is bilateral, treatment planning ismore » further complicated because only a limited number of beam angles can be used to avoid the prostheses. In this case study, we will report the observed advantages of using noncoplanar beams in the delivery of IMRT to a prostate cancer patient with bilateral hip prostheses. The treatment was planned for 75.6 Gy using a 7-field coplanar approach and a noncoplanar arrangement, with all fields avoiding entrance though the prostheses. Our results indicate that, compared with the coplanar plan, the noncoplanar plan delivers the prescribed dose to the target with a slightly better conformality and sparing of rectal tissue versus the coplanar plan.« less

  13. [Influence of preoperative bone mass density in periprosthetic bone remodeling after implantation of ABG-II prosthesis: A 10-year follow-up].

    PubMed

    Aguilar Ezquerra, A; Panisello Sebastiá, J J; Mateo Agudo, J

    2016-01-01

    Preoperative bone mass index has shown to be an important factor in peri-prosthetic bone remodelling in short follow-up studies. Bone density scans (DXA) were used to perform a 10-year follow-up study of 39 patients with a unilateral, uncemented hip replacement. Bone mass index measurements were made at 6 months, one year, 3 years, 5 years, and 10 years after surgery. Pearson coefficient was used to quantify correlations between preoperative bone mass density (BMD) and peri-prosthetic BMD in the 7 Gruen zones at 6 months, one year, 3 years, 5 years, and 10 years. Pre-operative BMD was a good predictor of peri-prosthetic BMD one year after surgery in zones 1, 2, 4, 5 and 6 (Pearson index from 0.61 to 0.75). Three years after surgery it has good predictive power in zones 1, 4 and 5 (0.71-0.61), although in zones 3 and 7 low correlation was observed one year after surgery (0.51 and 0.57, respectively). At the end of the follow-up low correlation was observed in the 7 Gruen zones. Sex and BMI were found to not have a statistically significant influence on peri-prosthetic bone remodelling. Although preoperative BMD seems to be an important factor in peri-prosthetic remodelling one year after hip replacement, it loses its predictive power progressively, until not being a major factor in peri-prosthetic remodelling ten years after surgery. Copyright © 2015 SECOT. Published by Elsevier Espana. All rights reserved.

  14. Periprosthetic bone loss in total hip arthroplasty. Polyethylene wear debris and the concept of the effective joint space.

    PubMed

    Schmalzried, T P; Jasty, M; Harris, W H

    1992-07-01

    Thirty-four hips in which there had been prosthetic replacement were selected for study because of the presence of linear (diffuse) or lytic (localized) areas of periprosthetic bone loss. In all hips, there was careful documentation of the anatomical location of the material that had been obtained for histological analysis, and the specific purpose of the removal of the tissue was for examination to determine the cause of the resorption of bone. Specimens from twenty-three hips were retrieved during an operation and from eleven hips, at autopsy. The area of bone loss was linear only in sixteen hips, lytic only in thirteen, and both linear and lytic in five. In all thirty-four hips, intracellular particulate debris was found in the macrophages that were present in the area of bone resorption. All thirty-four had intracellular particles of polyethylene, many of which were less than one micrometer in size. Thirty-one hips had extracellular particles of polyethylene as well. Twenty-two of the thirty-four hips had intracellular metallic debris; in ten, metallic debris was found extracellularly as well. Ten of the sixteen cemented specimens had intracellular and extracellular polymethylmethacrylate debris. In the mechanically stable prostheses--cemented and uncemented--polyethylene wear debris was identified in areas of bone resorption far from the articular surfaces. The number of macrophages in a microscopic field was directly related to the amount of particulate polyethylene debris that was visible by light microscopy. Although the gross radiographic appearances of linear bone loss and lytic bone loss were different, the histological appearance of the regions in which there was active bone resorption was similar. Regardless of the radiographic appearance and anatomical origin of the specimen, bone resorption was found to occur in association with macrophages that were laden with polyethylene debris. In general, the number of macrophages present had a direct relationship to the degree of bone resorption that was seen. We believe that these findings indicate that joint fluid penetrates far more extensively than previously thought, even in a well fixed component, along the interface between the prosthesis and bone and in the periprosthetic tissues; it is often more extensive than is shown by arthrography. We therefore suggest the concept of the effective joint space to include all periprosthetic regions that are accessible to joint fluid and thus accessible to particulate debris.(ABSTRACT TRUNCATED AT 400 WORDS)

  15. Ceramic-on-ceramic total hip arthroplasty in patients younger than 55 years.

    PubMed

    Shah, Roshan P; Scolaro, John A; Componovo, Roger; Garino, Jonathan P; Lee, Gwo-Chin

    2014-12-01

    To review the outcomes of 65 patients younger than 55 years who underwent uncemented total hip arthroplasty (THA) using third-generation ceramic-on-ceramic prostheses. Medical records of 30 men and 35 women (80 hips) aged 18 to 55 (mean, 39) years who underwent uncemented THA using third-generation ceramic-onceramic prostheses by a single surgeon were reviewed. 61 THAs used the Reflection cup with the Synergy stem (n=49), Spectron stem (n=7), or Anthology stem (n=5), and 19 THAs used the Trident cup with the Secur-Fit stem. Outcomes were assessed based on the UCLA Activity Score and Harris Hip Score, as well as radiolucency around the implants, malposition, and subsidence on radiographs. Patients were asked about their satisfaction with current activity level (yes/no), activity limitation (no limitation, musculoskeletal limitation, psychological impediments and lack of motivation, and pain or disability of the operative hip), and change in occupational activity level (same or similar, more active, and less active or disability). The mean follow-up period was 54 (range, 24-110) months. Six patients were excluded from the analysis owing to prosthetic failure secondary to ceramic liner fracture after falling (n=2), acetabular component loosening (n=1), intolerable squeak (n=1), periprosthetic fracture (n=1), and instability (n=1). The mean UCLA Activity Score improved from 4.0 (range, 1-10) to 7.7 (range, 2-10) [p<0.001], and the mean Harris Hip Score improved from 52.8 (range, 25-69) to 91.0 (range, 38-100) [p<0.001]. No hip had evidence of subsidence, loosening, or osteolysis. 52 (80%) patients were satisfied with their activity level; 28 (43%) patients reported no activity limitation; and 57 (88%) patients kept the same or similar occupation. Ceramic-on-ceramic THA achieved acceptable clinical and radiographic outcomes.

  16. One-stage revision of infected hip arthroplasty: outcome of 39 consecutive hips.

    PubMed

    Ilchmann, Thomas; Zimmerli, Werner; Ochsner, Peter Emil; Kessler, Bernhard; Zwicky, Lukas; Graber, Peter; Clauss, Martin

    2016-05-01

    There are various options for treating periprosthetic joint infection (PJI). Two-stage exchange has traditionally been the gold standard. However, if the appropriate surgical intervention is chosen according to a rational algorithm, the outcome is similar when using all types of interventions. In an observational cohort study, the outcome of patients with PJI after hip replacement treated with one-stage revision was analysed. All patients fulfilling all criteria for one-stage exchange according to the Infectious Diseases Society of America (IDSA) guidelines and six without preoperative identification of a microorganism were included. Implant removal, debridement and cemented or uncemented reimplantations were performed in a single intervention. If a cemented device was implanted, commercially available gentamicin cement was used in all cases. Antibiotic treatment was administered intravenously for at least 2 weeks, followed by oral therapy for a total duration of 3 months. Patients had standardised clinical and radiological follow-up visits. Between 1996 and 2011, 38 patients (39 hips) were treated with a one-stage procedure and followed for at least 2 years. Coagulase-negative staphylococci were the most frequent pathogens, and polymicrobial infection was observed in five cases. In 25 hips, an uncemented revision stem was implanted, and 37 hips received an acetabular reinforcement ring. The mean follow-up was 6.6 (2.0-15.1) years. No patient had persistent, recurrent or new infection. There were four stem revisions for aseptic loosening. The mean Harris Hip Score was 81 points (26-99) at the final follow-up. Excellent cure rate and function seen in our study suggest that one-stage exchange is a safe procedure, even without local antibiotic treatment, provided that the patient has no sinus tract or severe soft tissue damage, no major bone grafting is required and the microorganism is susceptible to orally administered agents with high bioavailability.

  17. 21 CFR 888.3320 - Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis. 888.3320 Section 888.3320 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic...

  18. 21 CFR 888.3320 - Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis. 888.3320 Section 888.3320 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic...

  19. 21 CFR 888.3320 - Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis. 888.3320 Section 888.3320 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic...

  20. [Revision hip arthroplasty by Waldemar Link custom-made total hip prosthesis].

    PubMed

    Medenica, Ivica; Luković, Milan; Radoicić, Dragan

    2010-02-01

    The number of patients undergoing hip arthroplasty revision is constantly growing. Especially, complex problem is extensive loss of bone stock and pelvic discontinuity that requires reconstruction. The paper presented a 50-year old patient, who ten years ago underwent a total cement artrhroplasty of the left hip. A year after the primary operation the patient had difficulties in walking without crutches. Problems intensified in the last five years, the patient had severe pain, totally limited movement in the left hip and could not walk at all. Radiographically, we found loose femoral component, massive loss of bone stock of proximal femur, acetabular protrusion and a consequent pelvic discontinuity. Clinically, a completely disfunctional left hip joint was registered (Harris hip score--7.1). We performed total rearthroplasty by a custom-made Waldemar Link total hip prosthesis with acetabular antiprotrusio cage and compensation of bone defects with a graft from the bone bank. A year after the operation, we found clinically an extreme improvement in Harris hip score--87.8. Radiographically, we found stability of implanted components, a complete graft integration and bone bridging across the site of pelvic discontinuity. Pelvic discontinuity and massive loss of proximal femoral bone stock is a challenging and complex entity. Conventional prostheses cannot provide an adequate fixation and stability of the hip. Application of custom-made prosthesis (measured specificaly for a patient) and additional alografting bone defects is a good method in revision surgery after unsuccessful hip arthroplasty with extensive bone defects.

  1. Carbon/PEEK composite materials as an alternative for stainless steel/titanium hip prosthesis: a finite element study.

    PubMed

    Rezaei, Farshid; Hassani, Kamran; Solhjoei, Nosratollah; Karimi, Alireza

    2015-12-01

    Total hip replacement (THR) has been ranked within the most typical surgical processes in the world. The durability of the prosthesis and loosening of prosthesis are the main concerns that mostly reported after THR surgeries. In THR, the femoral prosthesis can be fixed by either cement or cementless methods in the patient's bones. In both procedures, the stability of the prosthesis in the hosted bone has a key asset in its long-term durability and performance. This study aimed to execute a comparative finite element simulation to assess the load transfer between the prosthesis, which is made of carbon/PEEK composite and stainless steel/titanium, and the femur bone. The mechanical behavior of the cortical bone was assumed as a linear transverse isotropic while the spongy bone was modeled like a linear isotropic material. The implants were made of stainless steel (316L) and titanium alloy as they are common materials for implants. The results showed that the carbon/PEEK composites provide a flatter load transfer from the upper body to the leg compared to the stainless steel/titanium prosthesis. Furthermore, the results showed that the von Mises stress, principal stress, and the strain in the carbon/PEEK composites prosthesis were significantly lower than that made of the stainless steel/titanium. The results also imply that the carbon/PEEK composites can be applied to introduce a new optimum design for femoral prosthesis with adjustable stiffness, which can decrease the stress shielding and interface stress. These findings will help clinicians and biomedical experts to increase their knowledge about the hip replacement.

  2. 21 CFR 888.3380 - Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... device includes prostheses that consist of a metallic stem made of alloys, such as cobalt-chromium-molybdenum, with an integrated cylindrical trunnion bearing at the upper end of the stem that fits into a... head of the device to rotate on its stem. The prosthesis is intended for use with bone cement (§ 888...

  3. 21 CFR 888.3380 - Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... device includes prostheses that consist of a metallic stem made of alloys, such as cobalt-chromium-molybdenum, with an integrated cylindrical trunnion bearing at the upper end of the stem that fits into a... head of the device to rotate on its stem. The prosthesis is intended for use with bone cement (§ 888...

  4. 21 CFR 888.3380 - Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... device includes prostheses that consist of a metallic stem made of alloys, such as cobalt-chromium-molybdenum, with an integrated cylindrical trunnion bearing at the upper end of the stem that fits into a... head of the device to rotate on its stem. The prosthesis is intended for use with bone cement (§ 888...

  5. 21 CFR 888.3380 - Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... device includes prostheses that consist of a metallic stem made of alloys, such as cobalt-chromium-molybdenum, with an integrated cylindrical trunnion bearing at the upper end of the stem that fits into a... head of the device to rotate on its stem. The prosthesis is intended for use with bone cement (§ 888...

  6. 21 CFR 888.3380 - Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... device includes prostheses that consist of a metallic stem made of alloys, such as cobalt-chromium-molybdenum, with an integrated cylindrical trunnion bearing at the upper end of the stem that fits into a... head of the device to rotate on its stem. The prosthesis is intended for use with bone cement (§ 888...

  7. Technical note: validation of a motion analysis system for measuring the relative motion of the intermediate component of a tripolar total hip arthroplasty prosthesis.

    PubMed

    Chen, Qingshan; Lazennec, Jean Yves; Guyen, Olivier; Kinbrum, Amy; Berry, Daniel J; An, Kai-Nan

    2005-07-01

    Tripolar total hip arthroplasty (THA) prosthesis had been suggested as a method to reduce the occurrence of hip dislocation and microseparation. Precisely measuring the motion of the intermediate component in vitro would provide fundamental knowledge for understanding its mechanism. The present study validates the accuracy and repeatability of a three-dimensional motion analysis system to quantitatively measure the relative motion of the intermediate component of tripolar total hip arthroplasty prostheses. Static and dynamic validations of the system were made by comparing the measurement to that of a potentiometer. Differences between the mean system-calculated angle and the angle measured by the potentiometer were within +/-1 degrees . The mean within-trial variability was less than 1 degrees . The mean slope was 0.9-1.02 for different angular velocities. The dynamic noise was within 1 degrees . The system was then applied to measure the relative motion of an eccentric THA prosthesis. The study shows that this motion analysis system provides an accurate and practical method for measuring the relative motion of the tripolar THA prosthesis in vitro, a necessary first step towards the understanding of its in vivo kinematics.

  8. Wear particles and ions from cemented and uncemented titanium-based hip prostheses—A histological and chemical analysis of retrieval material

    PubMed Central

    Grosse, Susann; Haugland, Hans Kristian; Lilleng, Peer; Ellison, Peter; Hallan, Geir; Høl, Paul Johan

    2015-01-01

    Wear debris-induced inflammation is considered to be the main cause for periprosthetic osteolysis in total hip replacements (THR). The objective of this retrieval study was to examine the tissue reactions and exposure to metal ions and wear particles in periprosthetic tissues and blood samples from patients with titanium (Ti)-based hip prostheses that were revised due to wear, osteolysis, and/or aseptic loosening. Semiquantitative, histological tissue evaluations in 30 THR-patients revealed numerous wear debris-loaded macrophages, inflammatory cells, and necrosis in both groups. Particle load was highest in tissues adjacent to loosened cemented Ti stems that contained mainly submicron zirconium (Zr) dioxide particles. Particles containing pure Ti and Ti alloy elements were most abundant in tissues near retrieved uncemented cups. Polyethylene particles were also detected, but accounted only for a small portion of the total particle number. The blood concentrations of Ti and Zr were highly elevated in cases with high abrasive wear and osteolysis. Our findings indicate that wear particles of different chemical composition induced similar inflammatory responses, which suggests that particle size and load might be more important than the wear particle composition in periprosthetic inflammation and osteolysis. © 2014 The Authors. Journal of Biomedical Materials Research Part B: Applied Biomaterials Published by Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 103B:709–717, 2015. PMID:25051953

  9. Lower periprosthetic bone loss and good fixation of an ultra-short stem compared to a conventional stem in uncemented total hip arthroplasty.

    PubMed

    Salemyr, Mats; Muren, Olle; Ahl, Torbjörn; Bodén, Henrik; Eisler, Thomas; Stark, André; Sköldenberg, Olof

    2015-01-01

    We hypothesized that an ultra-short stem would load the proximal femur in a more physiological way and could therefore reduce the adaptive periprosthetic bone loss known as stress shielding. 51 patients with primary hip osteoarthritis were randomized to total hip arthroplasty (THA) with either an ultra-short stem or a conventional tapered stem. The primary endpoint was change in periprosthetic bone mineral density (BMD), measured with dual-energy x-ray absorptiometry (DXA), in Gruen zones 1 and 7, two years after surgery. Secondary endpoints were change in periprosthetic BMD in the entire periprosthetic region, i.e. Gruen zones 1 through 7, stem migration measured with radiostereometric analysis (RSA), and function measured with self-administered functional scores. The periprosthetic decrease in BMD was statistically significantly lower with the ultra-short stem. In Gruen zone 1, the mean difference was 18% (95% CI: -27% to -10%). In zone 7, the difference was 5% (CI: -12% to -3%) and for Gruen zones 1-7 the difference was also 5% (CI: -9% to -2%). During the first 6 weeks postoperatively, the ultra-short stems migrated 0.77 mm more on average than the conventional stems. 3 months after surgery, no further migration was seen. The functional scores improved during the study and were similar in the 2 groups. Up to 2 years after total hip arthroplasty, compared to the conventional tapered stem the ultra-short uncemented anatomical stem induced lower periprosthetic bone loss and had equally excellent stem fixation and clinical outcome.

  10. Evaluation of the effects of implant materials and designs on thermal necrosis of bone in cemented hip arthroplasty.

    PubMed

    Li, Chaodi; Kotha, Shiva; Mason, James

    2003-01-01

    The exothermic polymerization of bone cement may induce thermal necrosis of bone in cemented hip arthroplasty. A finite element formulation was developed to predict the evolution of the temperature with time in the cemented hip replacement system. The developed method is capable of taking into account both the chemical reaction that generates heat during bone cement polymerization (through a kinetic model) and the physical process of heat conduction (with an energy balance equation). The possibility of thermal necrosis of bone was then evaluated based on the temperature history in the bone and an appropriate damage criterion. Specifically, we evaluate the role of implant materials and designs on the thermal response of the system. Results indicated that the peak temperature at the bone/cement interface with a metal prosthesis was lower than that with a polymer or a composite prosthesis in hip replacement systems. Necrosis of bone was predicted to occur with a polymer or a composite prosthesis while no necrosis was predicted with a metal prosthesis in the simulated conditions. When reinforcing osteoporotic hips with injected bone cement in the cancellous core of the femur, the volume of bone cement implanted is increased which may increase the risk of thermal necrosis of bone. We evaluate whether this risk can be decreased through the use of an insulator to contain the bone cement. No thermal necrosis of bone was predicted with a 3 mm thick polyurethane insulator while more damage is predicted for the use of bone cement without the insulator. This method provides a numerical tool for the quantitative simulation of the thermal behavior of bone-cement-prosthesis designs and for examining and refining new designs computationally.

  11. Operative tactics and results of treatment of patients with coxarthrosis secondary to congenital high luxation of hip joints.

    PubMed

    Król, Roman; Rojewski, Marek; Kamiński, Adam; Popławski, Tomasz

    2007-01-01

    Treatment of the sequelae of congenital high luxation of the hip joint is a major challenge in prosthetic surgery, demanding from the operator thorough familiarity with the problem and experience in hop reconstructive surgery. The results of 4 years observation, of the treatment of 14 woman in the average age of 38 years old with 18 hip joints with congenital high luxation are presented. In all cases cementless total hip arthroplasty was made. Acetabular component of the prosthesis was implanted correctly and stable in its physiological placement. Femur was shortened average 4 cm and stabilized by cementless press-fit stem of prosthesis. The place of femur osteotomy was covered with autogenic spongy bone from resected caput of femur. The union was achieved after average 10 weeks. In clinical assessment there were obtained 10 very good, 5 good and 3 satisfactory clinical results. There were no superficial or deep infections, no neurological disorders and no loosening of components of implanted prostheses observed. 1. Careful planning and carrying out the operative procedures allow to insert the acetabular component of the prosthesis in its physiological place and achieve good results. 2. Shortening of femur and repositioning of components of prosthesis in 90 degrees knee flexion and also position on broken bed after operative procedure allowed to avoid neurological disorders. 3. Cementless and hydroxyapatite-covered femoral component of the prosthesis correctly stabilize place of femur osteotomy.

  12. Bone-preserving total hip arthroplasty in avascular necrosis of the hip-a matched-pairs analysis.

    PubMed

    Merschin, David; Häne, Richard; Tohidnezhad, Mersedeh; Pufe, Thomas; Drescher, Wolf

    2018-07-01

    Short-stem hip arthroplasty has the potential advantage of femoral bone stock preservation, especially in view of the expected revisions in the often relatively young patients. Despite short-stem hip prosthesis are increasingly used for total hip arthroplasty, there are no sufficient mid- and long-term results especially for patients with avascular femoral head osteonecrosis. The present study investigates mid-term functional results as well as the revision rate following implantation of a short-stem prosthesis. In the period 06/2005 until 12/2013, a total of 351 short-stem hip prostheses were implanted. The study included 331 complete data sets. A retrospective analysis was performed using the Oxford Hip Score. All revisions were registered. In a total of 331 prostheses, the Oxford Hip Score was "excellent" in 66.2%, "good" in 12.7%, "fair" in 13.0%, and "poor" in 8.2% with a mean follow-up of 57.4 months (SD ± 29.8; range 24-115). In 26 cases, aseptic osteonecrosis of the hip was the indication (7.9%). The Oxford Hip Score was "excellent" in 66.7%, "good" in 0.0%, "fair" in 20.8%, and "poor" in 12.5%. The cumulated five year survival rate was 96.7%. In mid-term observation, the Metha® short-stem prosthesis shows no disadvantage in functional outcome and in survival time compared to a standard hip stem. Providing a correct indication, the Metha® short stem is a valuable option in total hip arthroplasty for younger patients with avascular osteonecrosis of the femoral head. Evaluation has shown no significant differences between aseptic osteonecrosis and other indications.

  13. Comparison of two different rehabilitation programmes for thrust plate prosthesis: a randomized controlled study.

    PubMed

    Unver, Bayram; Karatosun, Vasfi; Gunal, Izge; Angin, Salih

    2004-02-01

    Weight bearing after total hip arthroplasty is postponed in order to prevent early loosening, but this negatively affects the rehabilitation programme. For the force transfer characteristics of thrust plate prosthesis (TPP), a new type of hip prosthesis used without cement is similar to the normal hip. We evaluated the possibilities of early weight bearing after TPP by comparing early partial with early full weight bearing. Randomized controlled study. Department of orthopaedics and traumatology in a university hospital. Sixty hips of 51 patients who underwent total hip arthroplasty with TPP were randomly assigned into two groups. Both groups received accelerated rehabilitation programmes: group 1 with early partial weight bearing and group 2 with early full weight bearing. Patients were evaluated by a blind observer preoperatively, at three months after surgery by clinical (measurement of range of hip motion (universal goniometry), muscle strength (Manual Muscle Test), functional test (6-minute walk test), hip function (Harris Hip Scoring System)) and radiographical parameters and one year after surgery by clinical (Harris Hip Scoring System) and radiographical parameters. Group 2 performed transfer activities earlier, had more walking distance at the time of discharge and shorter hospital stay than group 1. At three months, Harris Hip Score, muscle strength, 6-minute walk test, and duration of crutch use were significantly (p < 0.05) in favour of group 2. None of the patients in either group showed signs of loosening one year after the operation. These results suggest that patients with TPP can tolerate an accelerated rehabilitation programme with early weight bearing and will gain the goals of rehabilitation earlier.

  14. Early prosthetic hip joint infection treated with debridement, prosthesis retention and biofilm-active antibiotics: functional outcomes, quality of life and complications.

    PubMed

    Aboltins, C; Dowsey, M M; Peel, T; Lim, W K; Parikh, S; Stanley, P; Choong, P F

    2013-07-01

    Patients treated for early prosthetic joint infection (PJI) with surgical debridement, prosthesis retention and biofilm-active antibiotics, such as rifampicin or fluoroquinolones have a rate of successful infection eradication that is similar to patients treated with the traditional approach of prosthesis exchange. It is therefore important to consider other outcomes after PJI treatment that may influence management decisions, such as function, quality of life (QOL) and treatment-associated complications. To describe rates of successful treatment for patients with PJI undergoing surgical debridement, prosthesis retention and biofilm-active antibiotics and compare their functional outcomes, QOL and complication rates to patients without PJI. Nineteen patients treated for PJI after hip arthroplasty with debridement, prosthesis retention and biofilm-active antibiotics were matched to 76 controls who underwent hip arthroplasty with no infection. Cumulative survival free from treatment failure at 2 years was 88% (95% confidence interval, 59-97%). PJI cases had significant improvement from pre-arthroplasty to 12-months post-arthroplasty in function according to Harris Hip Score and QOL according to the 12-item Short Form Health Survey Physical Component Summary. There was no significant difference in the improvement between controls and cases. PJI was not a risk factor for poor function or QOL. Medical complications occurred more frequently in cases (6/19 (32%)) than controls (9/76 (12%); P = 0.04), with this difference being accounted for by drug reactions. Surgical complications were the same in the two groups. Treatment of PJI with debridement, prosthesis retention and biofilm-active antibiotics is successful, well tolerated and results in significant improvements in function and QOL, which are similar to patients without PJI. © 2013 The Authors; Internal Medicine Journal © 2013 Royal Australasian College of Physicians.

  15. Traditional and MLC based dose compensator design for patients with hip prostheses undergoing pelvic radiation therapy.

    PubMed

    Alecu, R; Alecu, M; Loomis, T; Ochran, T; He, T

    1999-01-01

    Perturbations in the dose distribution caused by a hip prosthesis when treating pelvic malignancies can result in unacceptable dose inhomogeneities within the target volume. Our results, obtained by in vivo exit dose measurements with diodes, showed a 55% reduction in the dose at the exit dmax of a lateral 15 MV photon beam after passing through a bilateral cobalt-chrome alloy hip prosthesis. Such an inhomogeneous dose distribution may decrease the curability. Solutions such as treatment techniques to avoid the prosthesis are often not the best choice as the dose to the rectum may be unacceptably high. In this work an alternative method of dose compensator is presented. Two types of dose compensators were designed based on a 3-D treatment planning system and CT images of a pelvic phantom containing a hip prosthesis: one was fabricated from a polyethylene-lead slab in the representation of step fringes and placed on a tray in the path of the beam while the other was produced by the use of several fields shaped with a multileaf collimator. The calculation procedures developed by the authors for generating the compensators are described. Results of film measurements performed in a phantom with and without the compensators in place are discussed.

  16. Selection of contact bearing couple materials for hip prosthesis using finite element analysis under static conditions

    NASA Astrophysics Data System (ADS)

    Arirajan, K. A.; Chockalingam, K.; Vignesh, C.

    2018-04-01

    Implants are the artificial parts to replace the missing bones or joints in human anatomy to give mechanical support. Hip joint replacement is an important issue in orthopaedic surgery. The main concern limiting the long-run success of the total hip replacement is the limited service life. Hip replacement technique is widely used in replacing the femur head and acetabular cup by materials that are highly biocompatible. The success of the artificial hip replacement depends upon proper material selection, structure, and shape of the hip prosthesis. Many orthopaedic analyses have been tried with different materials, but ended with partial success on the application side. It is a critical task for selecting the best material pair in the hip prosthesis design. This work develops the finite element analysis of an artificial hip implant to study highest von Mises stress, contact pressure and elastic strain occurs for the dissimilar material combination. The different bearing couple considered for the analysis are Metal on Metal, Metal on Plastic, Metal on Ceramic, Ceramic on Plastic, Ceramic on Ceramic combinations. The analysis is carried out at different static positions of a human (i.e) standing, sitting. The results reveals that the combination with metal in contact with plastic (i.e) Titanium femoral head paired with Ultra High Molecular Weight Poly Ethylene acetabular cup reduces maximum von Mises stress and also it gives lowest contact pressure than other combination of bearing couples.

  17. Increased migration of uncemented acetabular cups in female total hip arthroplasty patients with low systemic bone mineral density. A 2-year RSA and 8-year radiographic follow-up study of 34 patients.

    PubMed

    Finnilä, Sami; Moritz, Niko; SvedströM, Erkki; Alm, Jessica J; Aro, Hannu T

    2016-02-01

    Low bone mineral density (BMD) may jeopardize the initial component stability and delay osseointegration of uncemented acetabular cups in total hip arthroplasty (THA). We measured the migration of uncemented cups in women with low or normal BMD. We used radiostereometric analysis (RSA) to measure the migration of hydroxyapatite-coated titanium alloy cups with alumina-on-alumina bearings in THA of 34 female patients with a median age of 64 (41-78) years. 10 patients had normal BMD and 24 patients had low systemic BMD (T-score ≤ -1) based on dual-energy X-ray absorptiometry (DXA). Cup migration was followed with RSA for 2 years. Radiographic follow-up was done at a median of 8 (2-10) years. Patients with normal BMD did not show a statistically significant cup migration after the settling period of 3 months, while patients with low BMD had a continuous proximal migration between 3 and 12 months (p = 0.03). These differences in cup migration persisted at 24 months. Based on the perceived risk of cup revision, 14 of the 24 cases were "at risk" (proximal translation of 0.2 to 1.0 mm) in the low-BMD group and 2 of the 10 cases were "at risk" in the normal-BMD group (odds ratio (OR) = 8.0, 95% CI: 1.3-48). The radiographic follow-up showed no radiolucent lines or osteolysis. 2 cups have been revised for fractures of the ceramic bearings, but none for loosening. Low BMD contributed to cup migration beyond the settling period of 3 months, but the migrating cups appeared to osseointegrate eventually.

  18. CAD - CAM Procedures Used for Rapid Prototyping of Prosthetic Hip Joint Bone

    NASA Astrophysics Data System (ADS)

    Popa, Luminita I.; Popa, Vasile N.

    2016-11-01

    The article addresses the issue of rapid prototyping CAD/ CAM procedures, based on CT imaging, for custom implants dedicated to hip arthroplasty and the correlation study to be achieved between femoral canal shape, valued by modern imaging methods, and the prosthesis form. A set of CT images is transformed into a digital model using one of several software packages available for conversion. The purpose of research is to obtain prosthesis with compatible characteristics as close to the physiological, with an optimal adjustment of the prosthesis to the bone in which it is implanted, allowing the recovery of the patient physically, mentally and socially.

  19. Lower periprosthetic bone loss and good fixation of an ultra-short stem compared to a conventional stem in uncemented total hip arthroplasty

    PubMed Central

    Salemyr, Mats; Muren, Olle; Ahl, Torbjörn; Bodén, Henrik; Eisler, Thomas; Stark, André; Sköldenberg, Olof

    2015-01-01

    Background and purpose — We hypothesized that an ultra-short stem would load the proximal femur in a more physiological way and could therefore reduce the adaptive periprosthetic bone loss known as stress shielding. Patients and methods — 51 patients with primary hip osteoarthritis were randomized to total hip arthroplasty (THA) with either an ultra-short stem or a conventional tapered stem. The primary endpoint was change in periprosthetic bone mineral density (BMD), measured with dual-energy x-ray absorptiometry (DXA), in Gruen zones 1 and 7, two years after surgery. Secondary endpoints were change in periprosthetic BMD in the entire periprosthetic region, i.e. Gruen zones 1 through 7, stem migration measured with radiostereometric analysis (RSA), and function measured with self-administered functional scores. Results — The periprosthetic decrease in BMD was statistically significantly lower with the ultra-short stem. In Gruen zone 1, the mean difference was 18% (95% CI: −27% to −10%). In zone 7, the difference was 5% (CI: −12% to −3%) and for Gruen zones 1–7 the difference was also 5% (CI: −9% to −2%). During the first 6 weeks postoperatively, the ultra-short stems migrated 0.77 mm more on average than the conventional stems. 3 months after surgery, no further migration was seen. The functional scores improved during the study and were similar in the 2 groups. Interpretation — Up to 2 years after total hip arthroplasty, compared to the conventional tapered stem the ultra-short uncemented anatomical stem induced lower periprosthetic bone loss and had equally excellent stem fixation and clinical outcome. PMID:26134386

  20. [Tripolar arthroplasty for recurrent total hip prosthesis dislocation].

    PubMed

    Beaulé, P-E; Roussignol, X; Schmalzried, T-P; Udomkiat, P; Amstutz, H-C; Dujardin, F-H

    2003-05-01

    The purpose of this study was to assess the results of revision surgery for recurrent total hip prosthesis dislocation using a tripolar prosthesis composed of a conventional stem with a mobile head of an intermediary prosthesis measuring more than 40 mm and a modified cup. This technique was used in two centers in Rouen France and Los Angeles USA. Twenty-one hips in 21 patients were operated on. The mobile heads measured 40 to 47 mm. Mean patient age was 70 years (range 29-92). The indication for the tripolar prosthesis was reserved for extremely unstable hips in patients with major risk factors for recurrent dislocation. These 21 patients had experienced 95 dislocations. The acetabular cup was custom-made for the large-diameter heads. A cemented polyethylene cup was used in 14 cases and a press-fit metal-backed around a polyethylene insert in 7. The polyethylene thickness varied from 6.5 to 16 mm for the cemented cups and 4 to 5 mm for the press-fit cups. Fourteen femoral stems were left in place as were two press-fit cups where only the inserts were changed. Mean follow-up was 5.4 years (range 3-11.8). There has been no recurrent dislocation for 20 hips. One patient experienced a dislocation one week after surgery which required a second revision procedure to reposition the acetabular implant. Final outcome was good at 7.6 years for this hip. One patient who had not had any recurrent dislocation died 4 years after the revision surgery due to a cause unrelated to the prosthesis. Two patients were lost to follow-up at 3.7 and 6 years, both were pain free and had no radiological anomalies. Infection occurred in one patient undergoing chemotherapy for a myeloma; the head and neck had to be resected. For the 20 other patients, functional outcome, assessed with the UCLA score, showed improvement in pain (5.8 preoperatively, 9.2 at last follow-up), walking (4.8 and 8 respectively), function (4 and 6 respectively), and daily activities (3.3 and 5.2 respectively). A revision procedure was necessary for one patient during the 4(th) year because of a fracture of the polyethylene insert on a metal-back cup; the insert alone was changed. Excepting the patient with infection, there were no cases of certain or probable loosening during the follow-up. The tripolar prosthesis with a mobile cup and a large-diameter head appears to be a reliable solution for these severely unstable hips. The procedure can often be limited to the acetabular component, reducing morbidity. The thickness of the polyethylene cup is a limitation which may affect long-term survival. Search for a highly wear-resistant couple continues.

  1. Impact of a stance phase microprocessor-controlled knee prosthesis on level walking in lower functioning individuals with a transfemoral amputation.

    PubMed

    Eberly, Valerie J; Mulroy, Sara J; Gronley, JoAnne K; Perry, Jacquelin; Yule, William J; Burnfield, Judith M

    2014-12-01

    For individuals with transfemoral amputation, walking with a prosthesis presents challenges to stability and increases the demand on the hip of the prosthetic limb. Increasing age or comorbidities magnify these challenges. Computerized prosthetic knee joints improve stability and efficiency of gait, but are seldom prescribed for less physically capable walkers who may benefit from them. To compare level walking function while wearing a microprocessor-controlled knee (C-Leg Compact) prosthesis to a traditionally prescribed non-microprocessor-controlled knee prosthesis for Medicare Functional Classification Level K-2 walkers. Crossover. Stride characteristics, kinematics, kinetics, and electromyographic activity were recorded in 10 participants while walking with non-microprocessor-controlled knee and Compact prostheses. Walking with the Compact produced significant increase in velocity, cadence, stride length, single-limb support, and heel-rise timing compared to walking with the non-microprocessor-controlled knee prosthesis. Hip and thigh extension during late stance improved bilaterally. Ankle dorsiflexion, knee extension, and hip flexion moments of the prosthetic limb were significantly improved. Improvements in walking function and stability on the prosthetic limb were demonstrated by the K-2 level walkers when using the C-Leg Compact prosthesis. Understanding the impact of new prosthetic designs on gait mechanics is essential to improve prescription guidelines for deconditioned or older persons with transfemoral amputation. Prosthetic designs that improve stability for safety and walking function have the potential to improve community participation and quality of life. © The International Society for Prosthetics and Orthotics 2013.

  2. Adventure sports and sexual freedom hip replacement: the tripolar hip.

    PubMed

    Pritchett, James W

    2018-01-01

    Certain athletic activities and lifestyles require a completely stable and very mobile hip. Total hip replacement with a natural femoral head size and two mobile-bearing surfaces (i.e., a "tripolar" prosthesis) is the most stable prosthesis. Elegant design and wear-resistant bearing surfaces are the keys to long-term implant survivorship. The hypothesis is that a ceramic-coated tripolar prosthesis using highly cross-linked polyethylene can provide full function and complete stability with low wear. This study sought to determine: (1) patient-reported outcomes, (2) functional outcomes, (3) implant survivorship and complications, and (4) postoperative sexual limitations. Between 1998 and 2011, the author performed 160 primary total hip replacements using tripolar prostheses in patients participating in adventure sports and other physically demanding activities. The institutional review board approved this study. The inclusion criteria were patients who needed unrestricted activity and who were not candidates for or did not choose hip resurfacing. Patients were followed every second year and assessed with radiographs, Harris Hip Score, WOMAC, SF-12, and UCLA functional outcome scores. Patients were asked about symptoms of instability and satisfaction with their hip replacement. Patients were asked both preoperatively and 2 years postoperatively four questions about their sexual activity. Mean follow-up was 11 years. At 2 years' postoperatively, 98% of patients reported their satisfaction as excellent or good and 99% were not limited for sexual activity following surgery. Seventy-four percent of patients reported they were recovered within 6 weeks of surgery. There were no dislocations. There were three revision procedures for implant loosening, infection, and periprosthetic fracture, but there were no failures of the tripolar articulation. The mean postoperative UCLA score was the highly athletic score of 8. There were no signs of osteolysis, wear, or metal sensitivity reactions. The range of motion achieved, sexual, and functional outcomes were higher than with other types of total hip replacement. This ceramic-coated tripolar prosthesis using highly cross-linked polyethylene provides full function, complete stability, and low wear to younger, active patients, thus confirming the hypothesis and clinical relevance.

  3. Debridement, antibiotics, irrigation, and retention (DAIR) of the prosthesis after hip hemiarthroplasty infections. Does it work?

    PubMed

    Kazimoglu, Cemal; Yalcin, Nadir; Onvural, Burak; Akcay, Serkan; Agus, Haluk

    2015-08-01

    Debridement, antibiotic, and implant retention (DAIR) is an attractive treatment modality after hip hemiarthroplasty (HA) infections. Data about the success of the procedure after acute onset infections is lacking. The aim of this study was to analyze the clinical outcome and associated risk factors. A multicenter, retrospective cohort study was designed, including 39 patients with acute onset prosthetic infection who had undergone debridement and irrigation with prosthesis retention. The primary outcome measure was infection eradication without prosthesis removal. We also analyzed how the success rate was influenced by the length of the interval between implantation of the prosthesis and the beginning of the treatment. The overall success rate was 41%. Sedimentation rate over 60 mm/h and the longer duration (2 weeks) after prosthesis implantation were found as factors negatively influencing the success rate. Our results indicated limited success to DAIR- treated patients with infected HA. The high failure rate of DAIR treatment after 2 weeks from the implantation should be taken into consideration.

  4. Neck fracture of a cementless forged titanium alloy femoral stem following total hip arthroplasty: a case report and review of the literature

    PubMed Central

    Grivas, Theodoros B; Savvidou, Olga D; Psarakis, Spyridon A; Bernard, Pierre-Francois; Triantafyllopoulos, George; Kovanis, Ioannis; Alexandropoulos, Panagiotis

    2007-01-01

    Introduction Fractures of the neck of the femoral component have been reported in uncemented total hip replacements, however, to our knowledge, no fractures of the neck of a cementless forged titanium alloy femoral stem coated in the proximal third with hydroxy-apatite have been reported in the medical literature. Case presentation This case report describes a fracture of the neck of a cementless forged titanium alloy stem coated in the proximal third with hydroxy-apatite. Conclusion The neck of the femoral stem failed from fatigue probably because of a combination of factors described analytically below. PMID:18062807

  5. Joint registries as continuous surveillance systems: the experience of the Catalan Arthroplasty Register (RACat).

    PubMed

    Allepuz, Alejandro; Martínez, Olga; Tebé, Cristian; Nardi, Joan; Portabella, Frederic; Espallargues, Mireia

    2014-03-01

    The aim was to present results on prosthesis performance in Catalonia for the period 2005-2010. All publicly funded hospitals submit in an electronic format data on hip and knee arthroplasties: patients' insurance identification number, hospital, joint (hip/knee), type of arthroplasty (primary/revision), side (right/left), date of surgery and prosthesis (manufacturer name and catalogue number). A standard survival analysis based on Kaplan-Meier estimation was carried out. Fifty-two hospitals have sent information to the RACat which has data on 36,951 knee and 26,477 hip arthroplasties. Cumulative prostheses revision risks at 3 years were 3.3% (95% CI: 3.1-3.6) for knee, 2.9% (95% CI: 2.5-3.3) for total hip and 2.5% (95% CI: 2.0-3.1) for partial hip. When compared to other registries a higher risk of revision was observed. © 2013.

  6. Biomechanical evaluation of two types of short-stemmed hip prostheses compared to the trust plate prosthesis by three-dimensional measurement of micromotions.

    PubMed

    Fottner, Andreas; Schmid, Markus; Birkenmaier, Christof; Mazoochian, Farhad; Plitz, Wolfgang; Volkmar, Jansson

    2009-06-01

    Stemless and short-stemmed hip prostheses have been developed to preserve femoral bone stock. While all these prostheses claim a more or less physiological load transfer, clinical long-term results are only available for the stemless thrust plate prosthesis. In this study, the in vitro primary stability of the thrust plate prosthesis was compared to two types of short-stemmed prostheses. In addition to the well-established Mayo prosthesis, the modular Metha prosthesis was tested using cone adapters with 130 degrees and 140 degrees neck-shaft-angles. The prostheses were implanted in composite femurs and loaded dynamically (300-1700 N). Three-dimensional micromotions at the bone-prosthesis interface were measured. In addition, the three-dimensional deformations at the surface of the composite femur were measured to gain data on the strain distribution. For all tested prostheses, the micromotions did not exceed 150 microm, the critical value for osteointegration. The thrust plate prosthesis revealed similar motions as the short-stemmed prostheses. The short-stemmed prosthesis with the 130 degrees cone tended to have the highest micromotions of all tested short-stemmed prostheses. The thrust plate prosthesis revealed the lowest alteration of bone surface deformation after implantation. The comparably low micromotions of the thrust plate prosthesis and the short-stemmed prostheses should be conducive to osseous integration. The higher alteration of load transmission after implantation reveals a higher risk of stress shielding for the short-stemmed prostheses.

  7. Hip Squeaking after Ceramic-on-ceramic Total Hip Arthroplasty

    PubMed Central

    Wu, Guo-Liang; Zhu, Wei; Zhao, Yan; Ma, Qi; Weng, Xi-Sheng

    2016-01-01

    Objective: The present study aimed to review the characteristics and influencing factors of squeaking after ceramic-on-ceramic (CoC) total hip arthroplasty (THA) and to analyze the possible mechanisms of the audible noise. Data Sources: The data analyzed in this review were based on articles from PubMed and Web of Science. Study Selection: The articles selected for review were original articles and reviews found based on the following search terms: “total hip arthroplasty”, “ceramic-on-ceramic”, “hip squeaking”, and “hip noise.” Results: The mechanism of the squeaking remains unknown. The possible explanations included stripe wear, edge loading, a third body, fracture of the ceramic liner, and resonance of the prosthesis components. Squeaking occurrence is influenced by patient, surgical, and implant factors. Conclusions: Most studies indicated that squeaking after CoC THA was the consequence of increasing wear or impingement, caused by prosthesis design, patient characteristics, or surgical factors. However, as conflicts exist among different articles, the major reasons for the squeaking remain to be identified. PMID:27453238

  8. [Screening with angiographic images prior to (99m)Tc-HMPAO labelled leukocyte scintigraphy in the diagnosis of periprosthetic infection].

    PubMed

    Granados, U; Fuster, D; Soriano, A; García, S; Bori, G; Martínez, J C; Mayoral, M; Perlaza, P; Tomás, X; Pons, F

    2015-01-01

    To evaluate the impact of the angioscintigrapy of the three phase bone scan as screening method to rule out infection of the hip and knee prosthesis prior to performing the (99m)Tc-HMPAO leukocyte scintigraphy. A total of 120 (70 women, 50 men; mean age 71±11years) with clinical suspicion of hip (n=63) or knee (n=57) infection of the prosthesis and clinical suspicion of infection were evaluated prospectively. All patients underwent three-phase bone scan (angioscintigraphy, vascular and bone phase) and (99m)Tc-HMPAO-labelled white blood cell scintigraphy. Final diagnosis of infection was made by microbiological documentation or clinical follow-up for at least 12months. Eighteen out of 120 patients were diagnosed of infection of hip prosthesis (n=10) or knee prosthesis (n=8). The angioscintigraphy was positive in 15/18 infected cases and in 21/102 of the non-infected cases with a sensitivity of 83%, specificity of 79% and negative predictive value of 97%. Sensitivity and specificity of (99m)Tc-HMPAO leukocyte scintigraphy were 72% and 95%, respectively. If the leukocyte labeled scintigraphies had been used exclusively for patients with positive angioscintigraphy, this would have saved up to 70% of the (99m)Tc-HMPAO leukocyte scintigraphies performed. There were no cases of infection with positive labeled leukocyte scintigraphy and negative angioscintigraphy. Angioscintigraphy (blood flow phase of bone scan) is a useful technique for screening for hip and knee joint prosthesis infection, significantly reducing the need for (99m)Tc-HMPAO leukocyte scintigraphy without affecting the sensitivity of the technique. Copyright © 2014 Elsevier España, S.L.U. and SEMNIM. All rights reserved.

  9. Midterm results of "thrust plate" prosthesis.

    PubMed

    Fink, Bernd; Wessel, Stephanie; Deuretzbacher, Georg; Protzen, Michael; Ruther, Wolfgang

    2007-08-01

    The aim of this investigation was to analyze the midterm results obtained with the metaphyseal fixation principle of the thrust plate prosthesis (TPP). Survival of 214 implants in 204 patients was analyzed. Clinical (Harris hip score) and radiologic examinations were carried out on 157 of 190 TPP with a postimplantation follow-up period of at least 5 years. Failure rate was 7.0% (9 aseptic and 6 septic loosening). Harris hip score increased from 36.9 +/- 13.5 points preoperatively to 91.2 +/- 13.1 points at follow-up. Eleven TPPs showed radiolucent lines not indicating prosthetic loosening. Thrust plate prosthesis is not an alternative to stemmed endoprostheses. It may be rarely indicated in very young patients where, because of their age, several revision operations can be expected.

  10. Activation of hip prostheses in high energy radiotherapy and resultant dose to nearby tissue.

    PubMed

    Keehan, Stephanie; Smith, Ryan L; Millar, Jeremy; Esser, Max; Taylor, Michael L; Lonski, Peta; Kron, Tomas; Franich, Rick D

    2017-03-01

    High energy radiotherapy can produce contaminant neutrons through the photonuclear effect. Patients receiving external beam radiation therapy to the pelvis may have high-density hip prostheses. Metallic materials such as those in hip prostheses, often have high cross-sections for neutron interaction. In this study, Thackray (UK) prosthetic hips have been irradiated by 18 MV radiotherapy beams to evaluate the additional dose to patients from the activation products. Hips were irradiated in- and out-of field at various distances from the beam isocenter to assess activation caused in-field by photo-activation, and neutron activation which occurs both in and out-of-field. NaI(Tl) scintillator detectors were used to measure the subsequent gamma-ray emissions and their half-lives. High sensitivity Mg, Cu, P doped LiF thermoluminescence dosimeter chips (TLD-100H) were used to measure the subsequent dose at the surface of a prosthesis over the 12 h following an in-field irradiation of 10,000 MU to a hip prosthesis located at the beam isocenter in a water phantom. 53 Fe, 56 Mn, and 52 V were identified within the hip following irradiation by radiotherapy beams. The dose measured at the surface of a prosthesis following irradiation in a water phantom was 0.20 mGy over 12 h. The dose at the surface of prostheses irradiated to 200 MU was below the limit of detection (0.05 mGy) of the TLD100H. Prosthetic hips are activated by incident photons and neutrons in high energy radiotherapy, however, the dose resulting from activation is very small. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  11. Added value of 18F-FDG PET/CT in diagnosing infected hip prosthesis.

    PubMed

    Kwee, Robert M; Broos, Wouter Am; Brans, Boudewijn; Walenkamp, Geert Him; Geurts, Jan; Weijers, René E

    2018-05-01

    Background The diagnosis of infected hip prosthesis is frequently not straightforward yet very important as it changes treatment. Purpose To retrospectively investigate the added value of 18F-FDG PET/CT to conventional tests including radiography, erythrocyte sedimentation rate (ESR)/C-reactive protein (CRP) testing, and joint aspiration, in diagnosing infected hip prosthesis. Material and Methods Seventy-eight hip prostheses of 78 patients (55% men; mean age = 66.5 years; age range = 30-85 years) with non-specific clinical presentation, i.e. no abscess or sinus tract communicating with the joint space at clinical examination, were analyzed. Cultures of intra-articular fluid and peri-implant tissues after revision surgery or clinical follow-up ≥6 months served as gold standard. Areas under the receiver operating characteristic curves (AUCs) of radiography, ESR/CRP testing, aspiration culture, and white blood cell (WBC) count without and with the addition of 18F-FDG PET/CT were compared. Results The addition of 18F-FDG PET/CT increased AUCs: for radiography with 0.212, P = 0.001; for ESR/CRP testing with 0.076, P = 0.072; for aspiration culture with 0.126, P = 0.032; and for aspiration WBC count with 0.191, P = 0.035. Conclusion This study shows that 18F-FDG PET/CT adds to individual conventional tests in diagnosing infected hip prosthesis. It may improve the preoperative planning and should therefore be considered in the diagnostic work-up. Future studies should define the exact place of 18F-FDG PET/CT in the diagnostic work-up of periprosthetic joint infection.

  12. Raised levels of metal ions in the blood in patients who have undergone uncemented metal-on-polyethylene Trident-Accolade total hip replacement.

    PubMed

    Craig, P; Bancroft, G; Burton, A; Collier, S; Shaylor, P; Sinha, A

    2014-01-01

    The issues surrounding raised levels of metal ions in the blood following large head metal-on-metal total hip replacement (THR), such as cobalt and chromium, have been well documented. Despite the national popularity of uncemented metal-on-polyethylene (MoP) THR using a large-diameter femoral head, few papers have reported the levels of metal ions in the blood following this combination. Following an isolated failure of a 44 mm Trident-Accolade uncemented THR associated with severe wear between the femoral head and the trunnion in the presence of markedly elevated levels of cobalt ions in the blood, we investigated the relationship between modular femoral head diameter and the levels of cobalt and chromium ions in the blood following this THR. A total of 69 patients received an uncemented Trident-Accolade MoP THR in 2009. Of these, 43 patients (23 men and 20 women, mean age 67.0 years) were recruited and had levels of cobalt and chromium ions in the blood measured between May and June 2012. The patients were then divided into three groups according to the diameter of the femoral head used: 12 patients in the 28 mm group (controls), 18 patients in the 36 mm group and 13 patients in the 40 mm group. A total of four patients had identical bilateral prostheses in situ at phlebotomy: one each in the 28 mm and 36 mm groups and two in the 40 mm group. There was a significant increase in the mean levels of cobalt ions in the blood in those with a 36 mm diameter femoral head compared with those with a 28 mm diameter head (p = 0.013). The levels of cobalt ions in the blood were raised in those with a 40 mm diameter head but there was no statistically significant difference between this group and the control group (p = 0.152). The levels of chromium ions in the blood were normal in all patients. The clinical significance of this finding is unclear, but we have stopped using femoral heads with a diameter of ≤ 36 mm, and await further larger studies to clarify whether, for instance, this issue particularly affects this combination of components.

  13. Tribological characterisation of UHMWPE used in dual mobility total hip prosthesis

    NASA Astrophysics Data System (ADS)

    Essefi, I.; Hakkouna, H.; Ouenzerfi, G.; Mollon, G.; Hamza, S.; Renault, E.; Berthier, Y.; Trunfio-Sfarghiu, A.-M.

    2016-08-01

    Total hip arthroplasty represents an effective solution for bone and joint diseases. Nevertheless, the hip prosthesis has a limited lifetime, in the average around fifteen years. Their improvement, especially their dual mobility is the objective of this study. Therefore, our strategy is focused on improving the material by comparing three types of polyethylene to determine the best one from a friction mechanism and wear rate minimization standpoint. A dual mobility hip prosthesis, containing a two-sided steel and cobalt chrome cup, was tested with a TORNIER hip joint simulator in calf serum. The rubbed surfaces were characterized using scanning electron microscopy (SEM), contact angle measurements, atomic force microscopy (AFM) and confocal fluorescence microscopy. All these multiscale characterization techniques (from nanoscale to millimeter and micro- scale) showed that the velocity accommodation mechanism is different from one type of polyethylene to another. The wear in the case of standard polyethylene was noticeable and the particles were large and scattered between the surface of polyethylene, the surface of the cup and in the calf serum. For the crosslinked polyethylene, the particles coming from the wear, were not as large, but they were spread the same way as the first case. Even though it shares the same accommodation principle on the detachment of the material with the crosslinked polyethylene the wear particles for the crosslinked vitaminized polyethylene were large and they were only found on the surface of the polyethylene.

  14. Reverse hybrid total hip arthroplasty.

    PubMed

    Wangen, Helge; Havelin, Leif I; Fenstad, Anne M; Hallan, Geir; Furnes, Ove; Pedersen, Alma B; Overgaard, Søren; Kärrholm, Johan; Garellick, Göran; Mäkelä, Keijo; Eskelinen, Antti; Nordsletten, Lars

    2017-06-01

    Background and purpose - The use of a cemented cup together with an uncemented stem in total hip arthroplasty (THA) has become popular in Norway and Sweden during the last decade. The results of this prosthetic concept, reverse hybrid THA, have been sparsely described. The Nordic Arthroplasty Register Association (NARA) has already published 2 papers describing results of reverse hybrid THAs in different age groups. Based on data collected over 2 additional years, we wanted to perform in depth analyses of not only the reverse hybrid concept but also of the different cup/stem combinations used. Patients and methods - From the NARA, we extracted data on reverse hybrid THAs from January 1, 2000 until December 31, 2013. 38,415 such hips were studied and compared with cemented THAs. The Kaplan-Meier method and Cox regression analyses were used to estimate the prosthesis survival and the relative risk of revision. The main endpoint was revision for any reason. We also performed specific analyses regarding the different reasons for revision and analyses regarding the cup/stem combinations used in more than 500 cases. Results - We found a higher rate of revision for reverse hybrids than for cemented THAs, with an adjusted relative risk of revision (RR) of 1.4 (95% CI: 1.3-1.5). At 10 years, the survival rate was 94% (CI: 94-95) for cemented THAs and 92% (95% CI: 92-93) for reverse hybrids. The results for the reverse hybrid THAs were inferior to those for cemented THAs in patients aged 55 years or more (RR =1.1, CI: 1.0-1.3; p < 0.05). We found a higher rate of early revision due to periprosthetic femoral fracture for reverse hybrids than for cemented THAs in patients aged 55 years or more (RR =3.1, CI: 2.2-4.5; p < 0.001). Interpretation - Reverse hybrid THAs had a slightly higher rate of revision than cemented THAs in patients aged 55 or more. The difference in survival was mainly caused by a higher incidence of early revision due to periprosthetic femoral fracture in the reversed hybrid THAs.

  15. Effects of Prosthesis Stem Tapers on Stress Distribution of Cemented Hip Arthroplasty

    NASA Astrophysics Data System (ADS)

    Abdullah, Abdul Halim; Nor, Mohd Asri Mohd; Saman, Alias Mohd; Tamin, Mohd Nasir; Kadir, Mohammed Rafiq Abdul

    2010-10-01

    Aseptic loosening effects are critical issues in encouraging long term stability of cemented hip arthroplasty. Stress shielding is believed to be an important factor that contributes to the aseptic loosening problems. The numerous changes in the prosthesis stem design are intended to minimize the stress shielding and aseptic loosening problems and to improve the long term performance of the implants. In this study, the stress distribution in cemented hip arthroplasty is established using finite element method. The taper of the prosthesis is designed to be 3° at anterior/posterior, 3° at medial/lateral and 10° from wide lateral to narrow medial. Major muscle loads and contact forces are simulated for walking (toe-off phase) and stair climbing load cases. Effects of prosthesis stem tapers on the resulting stress distribution are investigated. Results show that compressive stress dominates in the medial plane while tensile stress in the lateral plane of the femur. The corresponding stress levels of intact femur for walking and stair-climbing load cases are 22 and 29 MPa, respectively. The magnitude of Tresca stress for the THA femur in stair-climbing load case remains higher in the region of 85 MPa while the walking load case induces around 40 MPa. The stress range in the straight and single taper stem prosthesis is lower than 260 MPa, while localized Tresca stress is in the order of the yield strength of Ti-6Al-4V alloy for double and triple taper stem design.

  16. Acute bilateral ECT in a depressed patient with a hip-aztreonam-spacer and subsequent maintenance ECT after prosthesis collocation.

    PubMed

    Gálvez, Verònica; de Arriba Arnau, Aida; Martínez-Amorós, Erika; Ribes, Carmina; Urretavizcaya, Mikel; Cardoner, Narcís

    2014-11-10

    ABSTRACT Electroconvulsive Therapy (ECT) has been demonstrated to be a safe and effective treatment for geriatric depression, although its application might be challenging when medical comorbidities exist. The present case reports a 78-year-old man diagnosed with recurrent unipolar major depressive disorder (MDD), who presented with a severe depressive episode with psychotic features (DSM IV). He successfully received a course of bitemporal (BT) ECT with a hip-aztreonam-spacer due to a hip fracture that occurred during hospitalization. This was followed by maintenance ECT (M-ECT) with a recent prosthesis collocation. This particular case illustrates the importance of a multidisciplinary approach in geriatric patients with somatic complications receiving ECT.

  17. SU-E-T-612: Photonuclear Activation of Prosthetic Hips in Radiotherapy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Keehan, S; Taylor, M; Franich, R

    2015-06-15

    Purpose: To measure the neutron induced activation of a prosthetic hip when exposed to an 18 MV radiotherapy linac beam to assess the potential dose to patients. Methods: A prosthetic hip (Thackray, UK) was placed in a water phantom and irradiated (both in-field and out-of-field) with an 18 MV linac beam. Gamma spectroscopy was used to identify the radioisotopes produced. Following the in-field irradiation where the induced activity is higher, high sensitivity lithium fluoride Thermoluminescence Dosimeters (TLD-100H) (Harshaw, USA) were placed on the surface to measure the dose which would be deposited to nearby tissue resulting from the induced radioactivity.more » Results: The radioisotopes produced in the hip prosthesis have been identified as {sup 5{sup 2}}V, {sup 5{sup 3}}Fe, and {sup 56}Mn which have half-lives of 3.74, 8.51 and minutes respectively. The 378 and 511 keV characteristic peaks of {sup 5{sup 3}}Fe do not appear in the spectra collected from hips irradiated in the out-of-field region. This isotope is produced by photonuclear interactions within the hip itself. {sup 52}V and {sup 56}Mn appear in spectra collected from hips irradiated either within the photon beam or in the nearby out-of-field region, implying that they are produced by incident neutron radiation produced in components of the linear accelerator.The integrated dose which would be deposited in the tissue immediately surrounding the hip after four hours (1.5 half-lives of the longest lived product) was measured as approximately 100 µGy, following a 10,000 MU irradiation of the prosthesis. A highly accurate measurement of the dose is challenging because of the irregular shape of the prosthesis. Conclusion: The cumulative dose measured at the surface of the hip is 0.0001% of the in-field dose, and is therefore negligible compared with the doses the patient receives as a consequence of their treatment.« less

  18. Design of Composite Hip Prostheses Considering the Long-Term Behavior of the Femur

    NASA Astrophysics Data System (ADS)

    Lim, Jong Wan; Jeong, Jae Youn; Ha, Sung Kyu

    A design method for the hip prosthesis is proposed which can alleviate problems associated with stress shielding, proximal loosening and the high stress of bone-implant interfaces after total hip replacement. The stress shielding which may lead to bone resorption, can cause a loosening of the stem and a fracture of femoral bone. Generally the composites were more suitable for hip prosthesis material in the long-term stability than metallic alloy because design cases of composite materials produced less stress shielding than titanium alloy. A bone remodeling algorithm was implemented in a nonlinear finite element program to predict the long-term performance of the hip prosthesis. The three neck shapes and three cross sections of composite hip were examined. It was found that the stress concentration in the distal region of the titanium stem which may cause the patient's thigh pains was reduced using composite material. The head neck shape was closely related with the cortical bone resorption and the cancellous bone apposition at proximal region whereas the cross-section was closely related with the relative micromotion between interfaces. The convex head neck type with the quadrangle cross-section produced less subsidence at proximal region on the medial side than the others. For all composite material cases, the cancellous bone apposition occurred at partial interfaces, which may result in a stable bio-fixation. The design performances of the convex neck head type with the hexagonal cross-section designed to insure the long-term stability were found to be more suitable than the others.

  19. Shielding of the Hip Prosthesis During Radiation Therapy for Heterotopic Ossification is Associated with Increased Failure of Prophylaxis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Balboni, Tracy A.; Gaccione, Peter; Gobezie, Reuben

    2007-04-01

    Purpose: Radiation therapy (RT) is frequently administered to prevent heterotopic ossification (HO) after total hip arthroplasty (THA). The purpose of this study was to determine if there is an increased risk of HO after RT prophylaxis with shielding of the THA components. Methods and Materials: This is a retrospective analysis of THA patients undergoing RT prophylaxis of HO at Brigham and Women's Hospital between June 1994 and February 2004. Univariate and multivariate logistic regressions were used to assess the relationships of all variables to failure of RT prophylaxis. Results: A total of 137 patients were identified and 84 were eligiblemore » for analysis (61%). The median RT dose was 750 cGy in one fraction, and the median follow-up was 24 months. Eight of 40 unshielded patients (20%) developed any progression of HO compared with 21 of 44 shielded patients (48%) (p = 0.009). Brooker Grade III-IV HO developed in 5% of unshielded and 18% of shielded patients (p 0.08). Multivariate analysis revealed shielding (p = 0.02) and THA for prosthesis infection (p = 0.03) to be significant predictors of RT failure, with a trend toward an increasing risk of HO progression with age (p = 0.07). There was no significant difference in the prosthesis failure rates between shielded and unshielded patients. Conclusions: A significantly increased risk of failure of RT prophylaxis for HO was noted in those receiving shielding of the hip prosthesis. Shielding did not appear to reduce the risk of prosthesis failure.« less

  20. Femoral medullary infarction secondary to canine total hip arthroplasty.

    PubMed

    Sebestyen, P; Marcellin-Little, D J; DeYoung, B A

    2000-01-01

    To evaluate the prevalence of femoral intramedullary infarction after total hip arthroplasty (THA) and to determine whether any specific femoral morphology predisposes to bone infarction. Retrospective clinical study. All dogs from our hospital population undergoing THA between 1984 and 1997 with radiographic follow-up available at 1 year or more postoperatively. A case control study was conducted within the THA group to determine risk factors predisposing to femoral infarction after THA. Medical records and radiographs were reviewed. Data were collected on clinical parameters, femoral morphology, prosthesis, and bone changes. Radiographic diagnosis was confirmed using histopathology in 11 femora. Radiographs of 50 age-matched control dogs weighing more than 20 kg with coxofemoral degenerative joint disease were randomly chosen to determine the prevalence of bone infarction in nonoperated dogs. Ninety-one dogs with 110 THA were included in the study. Fifteen of the 110 femora with THA had radiographic evidence of infarction (14%). Infarction was not present in any femora in the control group. There was no significant difference in the prevalence of infarction between dogs that received cemented or uncemented prostheses. Clinical signs were not reported in any patient that developed femoral infarction. Young age (P = .03) and a distance between the greater trochanter and nutrient foramen greater than 79 mm (P = .008) predisposed dogs to femoral infarction. Over time, three infarcts decreased in size radiographically, five remained unchanged, and three expanded. An osteosarcoma developed at the site of a bone infarct in one dog. Femoral intramedullary infarction occurred in 15 of 110 THA. Young age at the time of THA and a greater distance between the greater trochanter and the nutrient foramen predisposed to infarction. Intramedullary infarction occurs after canine THA. These bone infarcts do not appear to cause clinical signs; however, they may present a diagnostic challenge. Malignant transformation could potentially result from medullary infarction.

  1. Influence of functionally graded pores on bone ingrowth in cementless hip prosthesis: a finite element study using mechano-regulatory algorithm.

    PubMed

    Tarlochan, Faris; Mehboob, Hassan; Mehboob, Ali; Chang, Seung-Hwan

    2018-06-01

    Cementless hip prostheses with porous outer coating are commonly used to repair the proximally damaged femurs. It has been demonstrated that stability of prosthesis is also highly dependent on the bone ingrowth into the porous texture. Bone ingrowth is influenced by the mechanical environment produced in the callus. In this study, bone ingrowth into the porous structure was predicted by using a mechano-regulatory model. Homogenously distributed pores (200 and 800 [Formula: see text]m in diameter) and functionally graded pores along the length of the prosthesis were introduced as a porous coating. Bone ingrowth was simulated using 25 and 12 [Formula: see text]m micromovements. Load control simulations were carried out instead of traditionally used displacement control. Spatial and temporal distributions of tissues were predicted in all cases. Functionally graded pore decreasing models gave the most homogenous bone distribution, the highest bone ingrowth (98%) with highest average Young's modulus of all tissue phenotypes approximately 4.1 GPa. Besides this, the volume of the initial callus increased to 8.33% in functionally graded pores as compared to the 200 [Formula: see text]m pore size models which increased the bone volume. These findings indicate that functionally graded porous surface promote bone ingrowth efficiently which can be considered to design of surface texture of hip prosthesis.

  2. Visibility of bony structures around hip prostheses in dual-energy CT: With or without metal artefact reduction software.

    PubMed

    Jeong, Jewon; Kim, Hyun-Joo; Oh, Eunsun; Cha, Jang Gyu; Hwang, Jiyoung; Hong, Seong Sook; Chang, Yun Woo

    2018-05-23

    The development of dual-energy CT and metal artefact reduction software provides a further chance of reducing metal-related artefacts. However, there have been only a few studies regarding whether MARs practically affect visibility of structures around a metallic hip prosthesis on post-operative CT evaluation. Twenty-seven patients with 42 metallic hip prostheses underwent DECT. The datasets were reconstructed with 70, 90 and 110 keV with and without MARs. The areas were classified into 10 zones according to the reference zone. All the images were reviewed in terms of the severity of the beam-hardening artefacts, differentiation of the bony cortex and trabeculae and visualization of trabecular patterns with a three-point scale. The metallic screw diameter was measured in the acetabulum with 110 keV images. The scores were the worst on 70 keV images without MARs [mean scores:1.84-4.22 (p < 0.001-1.000)]. The structures in zone II were best visualized on 110 keV (p < 0.001-0.011, mean scores: 2.86-5.22). In other zones, there is general similarity in mean scores whether applying MARs or not (p < 0.001-0.920). The mean diameter of the screw was 5.85 mm without MARs and 3.44 mm with MARs (mean reference diameter: 6.48 mm). The 110 keV images without MARs are best for evaluating acetabular zone II. The visibility of the bony structures around the hip prosthesis is similar in the other zones with or without MARs regardless of keV. MARS may not be needed for the evaluation of the metallic hip prosthesis itself at sufficient high-energy levels; however, MARS still has a role in the evaluation of other soft tissues around the prosthesis. © 2018 The Royal Australian and New Zealand College of Radiologists.

  3. Effects of hydroxyapatite coating of cups used in hip revision arthroplasty

    PubMed Central

    2012-01-01

    Background and purpose Coating of acetabular revision implants with hydroxyapatite (HA) has been proposed to improve ingrowth and stability. We investigated whether HA coating of revision cups can reduce the risk of any subsequent re-revision. Methods We studied uncemented cups either with or without HA coating that were used at a primary acetabular revision and registered in the Swedish Hip Arthroplasty Register (SHAR). 2 such cup designs were identified: Harris-Galante and Trilogy, both available either with or without HA coating. These cups had been used as revision components in 1,780 revisions of total hip arthroplasties (THA) between 1986 and 2009. A Cox proportional hazards model including the type of coating, age at index revision, sex, cause of cup revision, cup design, the use of bone graft at the revision procedure, and the type of cup fixation at primary THA were used to calculate adjusted risk ratios (RRs with 95% CI) for re-revision for any reason or due to aseptic loosening. Results 71% of the cups were coated with HA and 29% were uncoated. At a mean follow-up time of 6.9 (0–24) years, 159 (9%) of all 1,780 cups had been re-revised, mostly due to aseptic loosening (5%), dislocation (2%), or deep infection (1%). HA coating had no significant influence on the risk of re-revision of the cup for any reason (RR = 1.4, CI: 0.9–2.0) or due to aseptic loosening (RR = 1.1, 0.6–1.9). In contrast, HA coating was found to be a risk factor for isolated liner re-revision for any reason (RR = 1.8, CI: 1.01–3.3). Age below 60 years at the index cup revision, dislocation as the cause of the index cup revision, uncemented cup fixation at primary THA, and use of the Harris-Galante cup also increased the risk of re-revision of the cup. In separate analyses in which isolated liner revisions were excluded, bone grafting was found to be a risk factor for re-revision of the metal shell due to aseptic loosening (RR = 2.1, CI: 1.05–4.2). Interpretation We found no evidence to support the notion that HA coating improves the performance of the 2 studied cup designs in revision arthroplasty. In contrast, patient-related factors such as younger age and dislocation as the reason for cup revision, and technical factors such as the choice of revision cup were found to influence the risk of subsequent re-revision of the cup. The reason for inferior results after revision of uncemented cups is not known, but it is possible that these hips more often had pronounced bone loss at the index cup revision. PMID:22937978

  4. Computational Evaluation of the Effects of Bone Ingrowth on Bone Resorptive Remodeling after a Cementless Total Hip Arthroplasty

    NASA Astrophysics Data System (ADS)

    Jung, Duk-Young; Kang, Yu-Bong; Tsutsumi, Sadami; Nakai, Ryusuke; Ikeuchi, Ken; Sekel, Ron

    In this study, we simulated a wide cortex separation from a cementless hip prosthesis using the bone resorption remodeling method that is based on the generation of high compressive stress around the distal cortical bone. Thereafter, we estimated the effect on late migration quantities of the hip prosthesis produced by the interface state arising from bone ingrowth. This was accomplished using cortical bone remodeling over a long period of time. Two-dimensional natural hip and implanted hip FEM models were constructed with each of the following interface statements between the bone and prosthesis: (1) non-fixation, (2) proximal 1/3, (3) proximal 2/3 and (4) full-fixation. The fixation interfaces in the fully and partially porous coated regions were rigidly fixed by bony ingrowth. The non-fixation model was constructed as a critical situation, with the fibrous or bony tissue not integrated at all into the implant surface. The daily load history was generated using the three loading cases of a one-legged stance as well as abduction and adduction motions. With the natural hip and one-legged stance, the peak compressive principal stresses were found to be under the criteria value for causing bone resorption, while no implant movement occurred. The migration magnitude of the stem of the proximal 1/3 fixation model with adduction motion was much higher, reaching 6%, 11%and 21%greater than those of the non-fixation, proximal 2/3 fixation and all-fixation models, respectively. The full-fixation model showed the lowest compressive principal stress and implant movement. Thus, we concluded that the late loosening and subsequent movement of the stem in the long term could be estimated with the cortical bone remodeling method based on a high compressive stress at the bone-implant interface. The change caused at the bone-prosthesis interface by bony or fibrous tissue ingrowth constituted the major factor in determining the extent of cortical bone resorption occurring with clinical loosening and subsequent implant movement.

  5. Medical Research: A Bibliography of Walter Reed Army Medical Center Staff Publications, 1986-1989. Volume 1

    DTIC Science & Technology

    1990-01-01

    Wilson PD Jr: Fracture of the femoral component. Analysis of failure and long-term follow-up of rev-ision. Orthop Chin North Am 1988 Jul;19(3):637-47...DMED,DCI 88224857 Dysart SH, Savory CG, Callaghan JJ: Nonoperative treatment of a postoperative fracture around an uncemented porous-coated femoral...trochanter fractures of the hip without intertrochanteric extension: a case report. Milit Med 1988 Aug;153(8):421-3. DSURG 89015096 Lucente FE, Patow

  6. Thirteen-year outcomes in the Anatomique Benoist Girard II hip prosthesis.

    PubMed

    Catanach, Michael J M; Sorial, Rami M; Eslick, Guy D

    2015-04-01

    The Stryker Anatomique Benoist Girard (ABG) hip implant system was a commonly used cementless prosthesis in the early 2000s, which fell from favour after several studies emerged implicating the prosthesis in high rates of revision. This retrospective, single-surgeon clinical study examines the fracture rate, revision rate and reasons for revision in 500 consecutive ABG II primary total conventional hip replacements. Follow-up was conducted by audit of patient notes, patient mailout survey, patient phone contact and audit of the Australian National Joint Replacement Registry (NJRR) database to find instances of fracture and revision. End points were periprosthetic fracture and revision for any reason. Follow-up was 1.2-13.8 years with a mean of 6.58 years. Of the 500 hips, 17 (3.4%) had undergone a revision. Of these, 13 were due to periprosthetic fracture. Four further fractures occurred that were not revised. Eight of these periprosthetic fractures occurred within 1 year post-operatively. There were four revisions for recurrent dislocations. Kaplan-Meier survival curve demonstrates a 93.7% survivorship at 6.58 years for revision for any reason. Multivariate analysis showed the only statistically significant factor for increased risk of revision was smaller stem size. Our results were consistent with the literature in that the ABG II system has good medium-term results but is prone to periprosthetic fractures, especially in the early post-operative period. When used as a primary total hip arthroplasty, the ABG II system has an 8-year revision rate of 5.6% compared with the 4.9% of all primary total hip arthroplasties. © 2014 Royal Australasian College of Surgeons.

  7. Artifact Reduction in X-Ray CT Images of Al-Steel-Perspex Specimens Mimicking a Hip Prosthesis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Madhogarhia, Manish; Munshi, P.; Lukose, Sijo

    2008-09-26

    X-ray Computed Tomography (CT) is a relatively new technique developed in the late 1970's, which enables the nondestructive visualization of the internal structure of objects. Beam hardening caused by the polychromatic spectrum is an important problem in X-ray computed tomography (X-CT). It leads to various artifacts in reconstruction images and reduces image quality. In the present work we are considering the Artifact Reduction in Total Hip Prosthesis CT Scan which is a problem of medical imaging. We are trying to reduce the cupping artifact induced by beam hardening as well as metal artifact as they exist in the CT scanmore » of a human hip after the femur is replaced by a metal implant. The correction method for beam hardening used here is based on a previous work. Simulation study for the present problem includes a phantom consisting of mild steel, aluminium and perspex mimicking the photon attenuation properties of a hum hip cross section with metal implant.« less

  8. A rare presentation of haematuria: hip prosthesis in the bladder.

    PubMed

    Phan, Yih Chyn; Eli, Nnaemeka; Pillai, Praveen; O'Dair, Jonathan

    2018-03-22

    An 80-year-old woman presented to our department with visible haematuria and stage II acute kidney injury (AKI). She had stage IIB cervical cancer, for which she received chemotherapy and external beam radiotherapy in 2003. Four years later, she had a left dynamic hip screw for an extracapsular neck of femur fracture following a fall. In 2010, she underwent a right total hip replacement owing to osteoarthritis, and it was subsequently revised in 2012 owing to a right acetabular component failure. In this admission, her AKI improved with intravenous fluid administration and her haematuria settled following catheterisation with a three-way catheter and bladder irrigation with saline. She underwent a flexible cystoscopy which revealed that a part of her right hip prosthesis was in the bladder, having eroded through the right bony pelvis. However, she declined any surgical interventions. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  9. Space orientation of total hip prosthesis. A method for three-dimensional determination.

    PubMed

    Herrlin, K; Selvik, G; Pettersson, H

    1986-01-01

    A method for in vivo determination of orientation and relation in space of components of total hip prosthesis is described. The method allows for determination of the orientation of the prosthetic components in well defined anatomic planes of the body. Furthermore the range of free motion from neutral position to the point of contact between the edge of the acetabular opening and the neck of the femoral component can be determined in various directions. To assess the accuracy of the calculations a phantom prosthesis was studied in nine different positions and the measurements of the space oriented parameters according to the present method correlated to measurements of the same parameters according to Selvik's stereophotogrammetric method. Good correlation was found. The role of prosthetic malpositioning and component interaction evaluated with the present method in the development of prosthetic loosening and displacement is discussed.

  10. Gait alterations can reduce the risk of edge loading.

    PubMed

    Wesseling, Mariska; Meyer, Christophe; De Groote, Friedl; Corten, Kristoff; Simon, Jean-Pierre; Desloovere, Kaat; Jonkers, Ilse

    2016-06-01

    Following metal-on-metal hip arthroplasty, edge loading (i.e., loading near the edge of a prosthesis cup) can increase wear and lead to early revision. The position and coverage angle of the prosthesis cup influence the risk of edge loading. This study investigates the effect of altered gait patterns, more specific hip, and pelvis kinematics, on the orientation of hip contact force and the consequent risk of antero-superior edge loading using muscle driven simulations of gait. With a cup orientation of 25° anteversion and 50° inclination and a coverage angle of 168°, many gait patterns presented risk of edge loading. Specifically at terminal double support, 189 out of 405 gait patterns indicated a risk of edge loading. At this time instant, the high hip contact forces and the proximity of the hip contact force to the edge of the cup indicated the likelihood of the occurrence of edge loading. Although the cup position contributed most to edge loading, altering kinematics considerably influenced the risk of edge loading. Increased hip abduction, resulting in decreasing hip contact force magnitude, and decreased hip extension, resulting in decreased risk on edge loading, are gait strategies that could prevent edge loading. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1069-1076, 2016. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  11. [Charnley-type total hip prosthesis. Radiological technic of angular measurements of the acetabular piece (anteversion)].

    PubMed

    Chevrot, A; Najman, G

    1983-01-01

    A radiological technique is described based on the study of antero-posterior and lateral views of the hip. Mathematical calculations by trigonometry make it possible to deduce the degree of anteversion of the acetabular cup. The necessary tables are given.

  12. Automated estimation of hip prosthesis migration: a feasibility study

    NASA Astrophysics Data System (ADS)

    Vandemeulebroucke, Jef; Deklerck, Rudi; Temmermans, Frederik; Van Gompel, Gert; Buls, Nico; Scheerlinck, Thierry; de Mey, Johan

    2013-09-01

    A common complication associated with hip arthoplasty is prosthesis migration, and for most cemented components a migration greater than 0.85 mm within the first six months after surgery, are an indicator for prosthesis failure. Currently, prosthesis migration is evaluated using X-ray images, which can only reliably estimate migrations larger than 5 mm. We propose an automated method for estimating prosthesis migration more accurately, using CT images and image registration techniques. We report on the results obtained using an experimental set-up, in which a metal prosthesis can be translated and rotated with respect to a cadaver femur, over distances and angles applied using a combination of positioning stages. Images are first preprocessed to reduce artefacts. Bone and prosthesis are extracted using consecutive thresholding and morphological operations. Two registrations are performed, one aligning the bones and the other aligning the prostheses. The migration is estimated as the difference between the found transformations. We use a robust, multi-resolution, stochastic optimization approach, and compare the mean squared intensity differences (MS) to mutual information (MI). 30 high-resolution helical CT scans were acquired for prosthesis translations ranging from 0.05 mm to 4 mm, and rotations ranging from 0.3° to 3° . For the translations, the mean 3D registration error was found to be 0.22 mm for MS, and 0.15 mm for MI. For the rotations, the standard deviation of the estimation error was 0.18° for MS, and 0.08° for MI. The results show that the proposed approach is feasible and that clinically acceptable accuracies can be obtained. Clinical validation studies on patient images will now be undertaken.

  13. [Distal fixation prosthesis for unstable intertrochanteric fractures in elderly patients: a mid-term follow-up study].

    PubMed

    Zhang, Zhan-feng; Min, Ji-kang; Zhong, Jian-ming; Wang, Dan

    2016-06-01

    To explore mid-term follow up results of distal fixation prosthesis in treating unstable intertrochanteric fractures in elderly patients. From May 2008 to March 2014,58 elderly patients with unstable intertrochanteric were treated with distal fixation prosthesis, among them, there were 15 males and 43 females aged from 75 to 87 years old with an average of 83.2 years old. Fracture were classified according to Evans classification, 39 cases were type I c and 19 cases were type I d. Surgical risk was evaluated before operation, 9 patients were performed total hip arthroplasty and 49 patients were performed prosthetic replacement hip joint function of patients with different age period, Evans classificaton, prothesis type, fixation method were evaluated respectively by using Harris score. Fifty-six patients were followed up from 13 to 36 months with an average of 21.6 months. Harris score was 83.51 ± 6.40, 5 cases got excellent results, 38 cases good and 13 cases moderate. Harris score of patients aged from 75 to 80 years old was 88.64 ± 2.35, 81.64 ± 6.40 in patients aged more than 80 years old, and had significant differences between two groups; Harris score in patients with type Evans I c was 83.64 ± 6.53, and 83.11 ± 6.08 in type Evans I d, while there was no significant differences between two groups. There was no obvious meaning in Harris score between patients with tension band (83.63 ± 6.15) and without tension band (82.41 ± 6.57). There was no significant meaning in Harris score between patients with normal distal fixation prosthesis (83.34 ± 6.43) and femoral moment reconstruction distal fixation prosthesis (83.92 ± 6.51). There was 1 patient occurred hip joint dislocation on the operative side and re-dislocation after manual reduction, then received open reduction. Two patients occurred femoral osteolysis without clinical symptoms, and treated conservative treatment. Artificial joint replacement for unstable intertrochanteric fractures in elderly patients, hip joint function in patients aged more than 80 years old is worse, while there was no obvious market effect in fracture classification, whether to use tension band and type of distal fixation prosthesis, moreover, proximal femoral osteolysis should be focused on.

  14. Are CT Scans a Satisfactory Substitute for the Follow-Up of RSA Migration Studies of Uncemented Cups? A Comparison of RSA Double Examinations and CT Datasets of 46 Total Hip Arthroplasties

    PubMed Central

    Zeleznik, Michael P.; Nilsson, Kjell G.; Olivecrona, Henrik

    2017-01-01

    As part of the 14-year follow-up of a prospectively randomized radiostereometry (RSA) study on uncemented cup fixation, two pairs of stereo radiographs and a CT scan of 46 hips were compared. Tantalum beads, inserted during the primary operation, were detected in the CT volume and the stereo radiographs and used to produce datasets of 3D coordinates. The limit of agreement between the combined CT and RSA datasets was calculated in the same way as the precision of the double RSA examination. The precision of RSA corresponding to the 99% confidence interval was 1.36°, 1.36°, and 0.60° for X-, Y-, and Z-rotation and 0.40, 0.17, and 0.37 mm for X-, Y-, and Z-translation. The limit of agreement between CT and RSA was 1.51°, 2.17°, and 1.05° for rotation and 0.59, 0.56, and 0.74 mm for translation. The differences between CT and RSA are close to the described normal 99% confidence interval for precision in RSA: 0.3° to 2° for rotation and 0.15 to 0.6 mm for translation. We conclude that measurements using CT and RSA are comparable and that CT can be used for migration studies for longitudinal evaluations of patients with RSA markers. PMID:28243598

  15. Are CT Scans a Satisfactory Substitute for the Follow-Up of RSA Migration Studies of Uncemented Cups? A Comparison of RSA Double Examinations and CT Datasets of 46 Total Hip Arthroplasties.

    PubMed

    Otten, Volker; Maguire, Gerald Q; Noz, Marilyn E; Zeleznik, Michael P; Nilsson, Kjell G; Olivecrona, Henrik

    2017-01-01

    As part of the 14-year follow-up of a prospectively randomized radiostereometry (RSA) study on uncemented cup fixation, two pairs of stereo radiographs and a CT scan of 46 hips were compared. Tantalum beads, inserted during the primary operation, were detected in the CT volume and the stereo radiographs and used to produce datasets of 3D coordinates. The limit of agreement between the combined CT and RSA datasets was calculated in the same way as the precision of the double RSA examination. The precision of RSA corresponding to the 99% confidence interval was 1.36°, 1.36°, and 0.60° for X -, Y -, and Z -rotation and 0.40, 0.17, and 0.37 mm for X -, Y -, and Z -translation. The limit of agreement between CT and RSA was 1.51°, 2.17°, and 1.05° for rotation and 0.59, 0.56, and 0.74 mm for translation. The differences between CT and RSA are close to the described normal 99% confidence interval for precision in RSA: 0.3° to 2° for rotation and 0.15 to 0.6 mm for translation. We conclude that measurements using CT and RSA are comparable and that CT can be used for migration studies for longitudinal evaluations of patients with RSA markers.

  16. Radial Neck Dilatory Remodeling After Radial Head Arthroplasty With an Uncemented, Press Fit, Fully Chemically Etched Stem Design.

    PubMed

    Sullivan, Matthew P; Firoozabadi, Reza; Kennedy, Stephen A; Agel, Julie; Magnusson, Eric; Schiffman, Brett; Folchert, Matthew; Beingessner, Daphne

    2017-09-01

    To compare the radiographic outcomes of 2 widely used side loading, press fit, RHA implants used to reconstruct complex elbow trauma. Retrospective cohort study. Level-1 Academic trauma center. Patients undergoing RHA. Cohort 1 received Synthes Radial Head Prosthesis. Cohort 2 received Biomet ExploR Radial Head Replacement. Radial neck dilatory remodeling. Eighty-two subjects were included in final analysis, 63 from the Biomet Cohort, and 19 from Synthes cohort. Demographic and injury characteristics were similar among cohorts. Radial neck dilatory remodeling as well as periprosthetic radiographic lucency were seen significantly more frequently and to a significantly greater degree in the Synthes cohort. The average percentage of dilatory remodeling of the Synthes cohort was 34.9% and that of the Biomet cohort was 2.7%. There were no differences in rates of revision surgery. Our study demonstrates significant radiographic differences between 2 frequently used RHA implants. Radial neck dilatory remodeling is a common, rapidly progressive, and dramatic finding frequently seen with the Synthes Radial Head Prosthesis. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

  17. MRSA-infected external iliac artery pseudoaneurysm treated with endovascular stenting.

    PubMed

    Clarke, M G; Thomas, H G; Chester, J F

    2005-01-01

    A 48-year-old woman with severe juvenile-onset rheumatoid arthritis presented with a bleeding cutaneous sinus distal to her right total hip replacement scar. Methicillin resistant Staphylococcus aureus (MRSA) was isolated on culture. She had previously undergone bilateral total hip and knee replacements at aged 23 and six years later had the right knee prosthesis removed for infection, with subsequent osteomyelitis of the femoral shaft and right total hip prosthesis disruption. Peripheral arteriography was performed in view of persistent bleeding from the sinus, which revealed a 6 cm false aneurysm filling from and compressing the right external iliac artery (EIA). A PTFE-covered, balloon expandable JOSTENT was deployed in the right EIA, successfully excluding the false aneurysm and preventing further bleeding from the sinus. No graft infection was reported at 12 months. This case illustrates the potential use of endovascular stent-grafting in the treatment of an infected pseudoaneurysm.

  18. MRSA-Infected External Iliac Artery Pseudoaneurysm Treated with Endovascular Stenting

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Clarke, M.G.; Thomas, H.G.; Chester, J.F.

    2005-04-15

    A 48-year-old woman with severe juvenile-onset rheumatoid arthritis presented with a bleeding cutaneous sinus distal to her right total hip replacement scar. Methicillin resistant Staphylococcus aureus (MRSA) was isolated on culture. She had previously undergone bilateral total hip and knee replacements at aged 23 and six years later had the right knee prosthesis removed for infection, with subsequent osteomyelitis of the femoral shaft and right total hip prosthesis disruption. Peripheral arteriography was performed in view of persistent bleeding from the sinus, which revealed a 6 cm false aneurysm filling from and compressing the right external iliac artery (EIA). A PTFE-covered,more » balloon expandable JOSTENT was deployed in the right EIA, successfully excluding the false aneurysm and preventing further bleeding from the sinus. No graft infection was reported at 12 months. This case illustrates the potential use of endovascular stent-grafting in the treatment of an infected pseudoaneurysm.« less

  19. The transport of wear particles in the prosthetic hip joint: a computational fluid dynamics investigation.

    PubMed

    Hölzer, Andreas; Schröder, Christian; Woiczinski, Matthias; Sadoghi, Patrick; Müller, Peter E; Jansson, Volkmar

    2012-02-02

    The joint fluid mechanics and transport of wear particles in the prosthetic hip joint were analyzed for subluxation and flexion motion using computational fluid dynamics (CFD). The entire joint space including a moving capsule boundary was considered. It was found that particles suspended in the joint space are drawn into the joint gap between prosthesis cup and head during subluxation, which was also documented by Lundberg et al. (2007; Journal of Biomechanics 40, 1676-1685), however, wear particles remain in the joint gap. Wear particles leave the joint gap during flexion and can finally migrate to the proximal boundaries including the acetabular bone, where the particle deposition can cause osteolysis according to the established literature. Thus, the present study supports the theory of polyethylene wear particle induced osteolysis of the acetabular bone as a major factor in the loosening of hip prosthesis cups. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Hip arthroplasty with the thrust plate prosthesis in patients of 65 years of age or older: 67 patients followed 2-7 years.

    PubMed

    Karatosun, Vasfi; Unver, Bayram; Gunal, Izge

    2008-04-01

    Thrust plate prosthesis (TPP) is a relatively new concept in total hip arthroplasty and advocated to be used in young patients. We retrospectively evaluated the results of 67 patients (71 hips) who were older than 65 years of age and underwent hip arthroplasty using the TPP. There were 50 female and 17 male patients with a mean age 71 (range 65-89) years. All patients received accelerated rehabilitation program either with full weight bearing in the second postoperative day or at 6 weeks. All patients were followed-up for at least 2 years (range 28-87 months). The average Harris hip score improved from 43 (range 8-72) to 93 (range 64-100) at the latest follow-up (p < 0.001). The overall revision rate was 8.4%. However, when the patients with definitive history of trauma were excluded the rate for loosening and technical errors decreased to 4.2%. There was no significant difference between the Harris hip score of patients with full weight bearing in the second postoperative day or 6 weeks (p = 0.57). We conclude that the TPP could be indicated for older patients without age limit and that an accelerated rehabilitation program with early weight bearing can be applied to these patients.

  1. Curved-stem Hip Resurfacing

    PubMed Central

    2008-01-01

    Hip resurfacing is an attractive concept because it preserves rather than removes the femoral head and neck. Most early designs had high failure rates, but one unique design had a femoral stem. Because that particular device appeared to have better implant survival, this study assessed the clinical outcome and long-term survivorship of a hip resurfacing prosthesis. Four hundred forty-five patients (561 hips) were retrospectively reviewed after a minimum of 20 years’ followup or until death; 23 additional patients were lost to followup. Patients received a metal femoral prosthesis with a small curved stem. Three types of acetabular reconstructions were used: (1) cemented polyurethane; (2) metal-on-metal; and (3) polyethylene secured with cement or used as the liner of a two-piece porous-coated implant. Long-term results were favorable with the metal-on-metal combination only. The mean overall Harris hip score was 92 at 2 years of followup. None of the 121 patients (133 hips) who received metal-on-metal articulation experienced failure. The failure rate with polyurethane was 100%, and the failure rate with cemented polyethylene was 41%. Hip resurfacing with a curved-stem femoral component had a durable clinical outcome when a metal-on-metal articulation was used. Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18338217

  2. Fabrication and characterization of DLC coated microdimples on hip prosthesis heads.

    PubMed

    Choudhury, Dipankar; Ay Ching, Hee; Mamat, Azuddin Bin; Cizek, Jan; Abu Osman, Noor Azuan; Vrbka, Martin; Hartl, Martin; Krupka, Ivan

    2015-07-01

    Diamond like carbon (DLC) is applied as a thin film onto substrates to obtain desired surface properties such as increased hardness and corrosion resistance, and decreased friction and wear rate. Microdimple is an advanced surface modification technique enhancing the tribological performance. In this study, DLC coated microdimples were fabricated on hip prosthesis heads and their mechanical, material and surface properties were characterized. An Electro discharge machining (EDM) oriented microdrilling was utilized to fabricate a defined microdimple array (diameter of 300 µm, depth of 70 µm, and pitch of 900 µm) on stainless steel (SS) hip prosthesis heads. The dimpled surfaces were then coated by hydrogenated amorphous carbon (a-C:H) and tetrahedral amorphous carbon (Ta-C) layers by using a magnetron sputtering technology. A preliminary tribology test was conducted on these fabricated surfaces against a ceramic ball in simulated hip joint conditions. It was found that the fabricated dimples were perpendicular to the spherical surfaces and no cutting-tools wear debris was detected inside the individual dimples. The a-C:H and Ta-C coatings increased the hardness at both the dimple edges and the nondimpled region. The tribology test showed a significant reduction in friction coefficient for coated surfaces regardless of microdimple arrays: the lowest friction coefficient was found for the a-C:H samples (µ = 0.084), followed by Ta-C (µ = 0.119), as compared to the SS surface (µ = 0.248). © 2014 Wiley Periodicals, Inc.

  3. Bipolar Hemarthroplasty Using Cementless Conical Stem for Treatment of Dorr Type B and C Femoral Neck Fracture.

    PubMed

    Kang, Jeong Hoon; Lee, Sang Hong; Jung, Sung

    2015-12-01

    The current study aims to evaluate the clinical and the radiological outcome of bipolar hemiarthroplasty using cementless cone stem to treat osteoporotic femoral neck fracture and compare the results according to the proximal femur geometry. Seventy-five hips (75 patients) that underwent bipolar hemiarthroplasty with cementless cone stem between September 2006 and December 2011 were analyzed. The minimum follow-up period was 3 years. Thirty-three hips were classified as type B and 41 as type C. The clinical outcome was assessed using Harris hip score and the walking ability score. Radiographic evaluation was performed to evaluate the stability of the prosthesis. At the most recent follow up, the mean Harris hip score was 86 (range, 70-92) and 65% recovered to preoperative ambulatory status. In the radiographic exam, stable stem fixation was achieved in all cases. For the complications, eight hips developed deep vein thrombosis while three hips showed heterotopic ossification. Dislocation and delayed deep infection occurred in one hip resepectively. There were no significance differences in Harris hip score and walking ability score when the type B group was compare with the type C. Bipolar hemiarthroplasty with cementless cone stem showed an excellent early outcome both clinically and radiographically regardless of the shape of the proximal femur. We believe this prosthesis can provide early stability to the Dorr type B and C femur and is an effective treatment for treating osteoporotic femoral neck fracture.

  4. Painful hip prosthesis: value of nuclear imaging in the diagnosis of late complications

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pearlman, A.W.

    1980-04-01

    Loosening of the prosthesis and infection are the most common late complications of the Charnley low friction arthroplasty. A noninvasive diagnostic approach to the symptomatic patient, using plain radiographs and nuclear imaging with a bone imaging agent, is presented. Nuclear imaging is a more sensitive indicator than plain radiography, but the two studies supplement each other.

  5. [Total hip endoprosthesis following resection arthroplasty].

    PubMed

    Engelbrecht, E; Siegel, A; Kappus, M

    1995-08-01

    From 1976 to December 1994, a total of 347 patients underwent implantation of a hip prosthesis at the ENDO-Klinik for treatment of an unsatisfactory condition following resection arthroplasty. From 1976 to 1987, 143 patients were treated and in 1989 the results obtained in these patients were analysed: 99 of them were available for a follow-up examination in 1989, and 64 for a further examination in 1995. In 130 cases infection had been the reason for joint resection. At the time of the prosthesis operation (1-20 years later) intraoperative biopsy revealed that infection was still present in 41 cases (31.5%). Only 15 of these infections had been detected preoperatively by joint aspiration. This shows that the value of resection arthroplasty as a method of treating periprosthetic infection is limited and lends support to the one-stage exchange operation, which is the method we prefer in cases of infected hip prostheses. The operative technique and preparation for implantation of the prosthesis are described, as are septic and aseptic complications and the measures that can be taken to treat them. In spite of the patients' generally poor initial condition and with due consideration for the further revision operations, the medium-term results finally obtained are poor in only 9%.

  6. Prosthetic ankle push-off work reduces metabolic rate but not collision work in non-amputee walking.

    PubMed

    Caputo, Joshua M; Collins, Steven H

    2014-12-03

    Individuals with unilateral below-knee amputation expend more energy than non-amputees during walking and exhibit reduced push-off work and increased hip work in the affected limb. Simple dynamic models of walking suggest a possible solution, predicting that increasing prosthetic ankle push-off should decrease leading limb collision, thereby reducing overall energy requirements. We conducted a rigorous experimental test of this idea wherein ankle-foot prosthesis push-off work was incrementally varied in isolation from one-half to two-times normal levels while subjects with simulated amputation walked on a treadmill at 1.25 m · s(-1). Increased prosthesis push-off significantly reduced metabolic energy expenditure, with a 14% reduction at maximum prosthesis work. In contrast to model predictions, however, collision losses were unchanged, while hip work during swing initiation was decreased. This suggests that powered ankle push-off reduces walking effort primarily through other mechanisms, such as assisting leg swing, which would be better understood using more complete neuromuscular models.

  7. Prosthetic ankle push-off work reduces metabolic rate but not collision work in non-amputee walking

    NASA Astrophysics Data System (ADS)

    Caputo, Joshua M.; Collins, Steven H.

    2014-12-01

    Individuals with unilateral below-knee amputation expend more energy than non-amputees during walking and exhibit reduced push-off work and increased hip work in the affected limb. Simple dynamic models of walking suggest a possible solution, predicting that increasing prosthetic ankle push-off should decrease leading limb collision, thereby reducing overall energy requirements. We conducted a rigorous experimental test of this idea wherein ankle-foot prosthesis push-off work was incrementally varied in isolation from one-half to two-times normal levels while subjects with simulated amputation walked on a treadmill at 1.25 m.s-1. Increased prosthesis push-off significantly reduced metabolic energy expenditure, with a 14% reduction at maximum prosthesis work. In contrast to model predictions, however, collision losses were unchanged, while hip work during swing initiation was decreased. This suggests that powered ankle push-off reduces walking effort primarily through other mechanisms, such as assisting leg swing, which would be better understood using more complete neuromuscular models.

  8. Prosthetic ankle push-off work reduces metabolic rate but not collision work in non-amputee walking

    PubMed Central

    Caputo, Joshua M.; Collins, Steven H.

    2014-01-01

    Individuals with unilateral below-knee amputation expend more energy than non-amputees during walking and exhibit reduced push-off work and increased hip work in the affected limb. Simple dynamic models of walking suggest a possible solution, predicting that increasing prosthetic ankle push-off should decrease leading limb collision, thereby reducing overall energy requirements. We conducted a rigorous experimental test of this idea wherein ankle-foot prosthesis push-off work was incrementally varied in isolation from one-half to two-times normal levels while subjects with simulated amputation walked on a treadmill at 1.25 m·s−1. Increased prosthesis push-off significantly reduced metabolic energy expenditure, with a 14% reduction at maximum prosthesis work. In contrast to model predictions, however, collision losses were unchanged, while hip work during swing initiation was decreased. This suggests that powered ankle push-off reduces walking effort primarily through other mechanisms, such as assisting leg swing, which would be better understood using more complete neuromuscular models. PMID:25467389

  9. Impact of intraprosthetic drilling on the strength of the femoral stem in periprosthetic fractures: A finite element investigation.

    PubMed

    Brand, Stephan; Bauer, Michael; Petri, Maximilian; Schrader, Julian; Maier, Hans J; Krettek, Christian; Hassel, Thomas

    2016-07-01

    Treatment of periprosthetic femur fractures after total hip arthroplasty remains a major challenge in orthopedic surgery. Recently, a novel surgical technique using intraprosthetic screw fixation has been suggested. The purpose of this study was to evaluate the influence of drilling the femoral hip stem on integrity and strength of the implant. The hypothesis was that intraprosthetic drilling and screw fixation would not cause the load limit of the prosthesis to be exceeded and that deformation would remain within the elastic limit. A sawbone model with a conventional straight hip stem was used and a Vancouver C periprosthetic fracture was created. The fracture was fixed with a nine-hole less invasive stabilization system plate with two screws drilled and inserted through the femoral hip stem. Three different finite element models were created using ANSYS software. The models increased in complexity including joint forces and stress risers from three different dimensions. A variation of drilling positions was analyzed. Due to the complexity of the physiological conditions in the human femur, the most complex finite element model provided the most realistic results. Overall, significant changes in the stresses to the prosthesis caused by the drilling procedure were observed. While the stresses at the site of the bore hole decreased, the load increased in the surrounding stem material. This effect is more pronounced and further the holes were apart, and it was found that increasing the number of holes could counteract this. The maximum load was still found to be in the area of the prosthesis neck. No stresses above the load limit of titanium alloy were detected. All deformations of the prosthesis stem remained in the elastic range. These results may indicate a potential role for intraprosthetic screw fixation in the future treatment of periprosthetic femur fractures. © IMechE 2016.

  10. Perioperative mortality after hemiarthroplasty related to fixation method.

    PubMed

    Costain, Darren J; Whitehouse, Sarah L; Pratt, Nicole L; Graves, Stephen E; Ryan, Philip; Crawford, Ross W

    2011-06-01

    The appropriate fixation method for hemiarthroplasty of the hip as it relates to implant survivorship and patient mortality is a matter of ongoing debate. We examined the influence of fixation method on revision rate and mortality. We analyzed approximately 25,000 hemiarthroplasty cases from the AOA National Joint Replacement Registry. Deaths at 1 day, 1 week, 1 month, and 1 year were compared for all patients and among subgroups based on implant type. Patients treated with cemented monoblock hemiarthroplasty had a 1.7-times higher day-1 mortality compared to uncemented monoblock components (p < 0.001). This finding was reversed by 1 week, 1 month, and 1 year after surgery (p < 0.001). Modular hemiarthroplasties did not reveal a difference in mortality between fixation methods at any time point. This study shows lower (or similar) overall mortality with cemented hemiarthroplasty of the hip.

  11. [The Use of Jumbo Cups in Revision Total Hip Arthroplasty].

    PubMed

    von Roth, Philipp; Wassilew, Georgi I

    2017-10-01

    Extra-large uncemented jumbo cups are among the most common methods of acetabular revision. Jumbo cups do not contribute to bone stock restoration, and in the case of a subsequent revision, an even larger bone defect is to be expected. Thus, understanding long-term survival is essential. The present article discusses the literature relevant to this topic and addresses technical and implant-specific characteristics of jumbo cups. In summary, jumbo cups show an acceptable long-term survival rate, with aseptic loosening as the most common reason for revision and dislocation being the most common complication. Through the development of alternative revision systems, jumbo cups have lost their importance in today's practice. However, they can serve as a benchmark for studies of newer technologies in revision total hip arthroplasty. Georg Thieme Verlag KG Stuttgart · New York.

  12. [APPLICATION AND EFFECTIVENESS OF BIOLOGICAL TYPE ACETABULAR CUP IN ADULT Crowe TYPE IV DEVELOPMENTAL DYSPLASIA OF THE HIP].

    PubMed

    Xu, Ning; Sun, Junying; Zhao, Xijiang; Wang, Tao

    2016-01-01

    To investigate the application and effectiveness of the biological type acetabular cup(diameter < 44 mm) in adult Crowe type IV developmental dysplasia of the hip (DDH). Between April 2001 andAugust 2013, biological type acetabular cup was used in total hip arthroplasty for the treatment of Crowe type IV DDH in16 cases (20 hips). There were 3 males and 13 females, aged 31-69 years (mean, 49 years). Unilateral hip was involved in 12cases, and bilateral hips in 4 cases. The patients showed pain of the hip joint and inequality of lower limb (shortening ofaffected limb 1.8-6.0 cm in length, 3.5 cm on average). Acetabular deformity, the relationship and the severity of femoralhead dislocation were comfirmed on the X-ray films. The preoperative Harris score was 34.0 ± 6.9. All patientsachieved healing of incision by first intention, with no complication of infection or neurovascular injury. Sixteen caseswere followed up 4-12 years (mean, 7.5 years). At 2 weeks after operation, dislocation occurred in 2 cases, and were fixedwith plaster for 3 weeks after reduction of the hip. Postoperative X-ray films showed complete reduction of femoral head;the average acetabular coverage of the cup of the weight-bearing area was 98.5% (range, 98.2%-99.1%). The cup from theRanawat triangle was 4.6-7.0 mm (mean, 5.8 mm) in medial shifting, and was 4.5-7.9 mm (mean, 6.2 mm) in elevation,it located at cup lateral surface area inside the iliopectineal line and the Kohler line (< 40%); the cup abduction angle was(45 ± 5)degrees, and the anteversion angle was (10 ± 5)degrees. The other patients had no prosthesis loosening except 1 patient havingextensive acetabular prosthesis loosening because of acetabular osteolysis at 12 years after operation. The hip Harris scorewas significantly improved to 85.0 ± 7.5 at 1 year after operation (t = 14.34, P = 0.01). The acetabular grindingprocess to retain enough bone combined with a small cup of-biological prosthesis treating adult Crowe type IV DDH has theadvantages of satisfactory coverage and initial acetabular fixation, so good early and mid-term effectiveness can be obtained.

  13. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wronski, M; Sarfehnia, A; Sahgal, A

    Purpose: To evaluate the interface effects when irradiating through a hip prosthesis in the presence of an orthogonal 1.5 T magnetic field using Monte Carlo simulations. Methods: A 20×20×38 cm virtual phantom with two 5×5×5 cm sections of bilateral titanium hip prosthesis was created in GPU-based Monte Carlo (MC) algorithm (GPUMCD, Elekta AB, Stockholm Sweden). The lateral prosthesis spacing was based on a representative patient CT scan. A treatment SAD of 143.5 cm was chosen, corresponding to the Elekta AB MRI Linac and the beam energy distribution was sampled from a histogram representing the true MRI Linac spectrum. A magneticmore » field of 1.5 T was applied perpendicular to the plane of irradiation. Dose was calculated, in voxels of side 1 mm, for 2×2, 5×5, and 10×10 cm treatment field sizes with normal beam incidence (gantry at 90° or 270°) and at 5° and 10° from normal, representing the range of incidence through the bilateral prosthesis. Results: With magnetic field ON (B-On) and normal beam incidence the backscatter dose at the interfaces of proximal and distal implants is reduced for all the field sizes compared to the magnetic field OFF (B-Off) case. The absolute reduction in doses at the interface was in the range of 12.93% to 13.16% for the proximal implant and 13.57% to 16.12% for the distal implant. Similarly for the oblique incidences of 5o and 10o the dose in the plane adjacent to the prosthetic implants is lower when the magnetic field is ON. Conclusion: The dosimetric effects of irradiating through a hip prosthesis in the presence of a transverse magnetic field have been determined using MC simulation. The backscatter dose reduction translates into significantly lower hot spots at the prosthetic interfaces, which are otherwise substantially high in the absence of the magnetic field. This project was supported through funding provided by ElektaTM.« less

  14. Insufficient sensitivity of joint aspiration during the two-stage exchange of the hip with spacers.

    PubMed

    Boelch, Sebastian Philipp; Weissenberger, Manuel; Spohn, Frederik; Rudert, Maximilian; Luedemann, Martin

    2018-01-10

    Evaluation of infection persistence during the two-stage exchange of the hip is challenging. Joint aspiration before reconstruction is supposed to rule out infection persistence. Sensitivity and specificity of synovial fluid culture and synovial leucocyte count for detecting infection persistence during the two-stage exchange of the hip were evaluated. Ninety-two aspirations before planned joint reconstruction during the two-stage exchange with spacers of the hip were retrospectively analyzed. The sensitivity and specificity of synovial fluid culture was 4.6 and 94.3%. The sensitivity and specificity of synovial leucocyte count at a cut-off value of 2000 cells/μl was 25.0 and 96.9%. C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) values were significantly higher before prosthesis removal and reconstruction or spacer exchange (p = 0.00; p = 0.013 and p = 0.039; p = 0.002) in the infection persistence group. Receiver operating characteristic area under the curve values before prosthesis removal and reconstruction or spacer exchange for ESR were lower (0.516 and 0.635) than for CRP (0.720 and 0.671). Synovial fluid culture and leucocyte count cannot rule out infection persistence during the two-stage exchange of the hip.

  15. A novel tribological study on DLC-coated micro-dimpled orthopedics implant interface.

    PubMed

    Choudhury, Dipankar; Urban, Filip; Vrbka, Martin; Hartl, Martin; Krupka, Ivan

    2015-05-01

    This study investigates a tribological performance of diamond like carbon (DLC) coated micro dimpled prosthesis heads against ceramic cups in a novel pendulum hip joint simulator. The simulator enables determining friction coefficient and viscous effects of a concave shaped specimen interface (conformal contact). Two types of DLC such as hydrogenated amorphous carbon (a-C:H) and tetrahedral amorphous carbon (Ta-C) and one set of micro dimple (diameter of 300µm, depth of 70µm, and pitch of 900µm) were fabricated on metallic prosthesis heads. The experiment results reveal a significant friction coefficient reduction to the 'dimpled a-C:H/ceramic' prosthesis compared to a 'Metal (CoCr)/ceramic' prosthesis because of their improved material and surface properties and viscous effect. The post-experiment surface analysis displays that the dimpled a-C:H yielded a minor change in the surface roughness, and generated a larger sizes of wear debris (40-200nm sized, equivalent diameter), a size which could be certainly stored in the dimple, thus likely to reducing their possible third body abrasive wear rate. Thus, dimpled a:C-H can be used as a 'metal on ceramic hip joint interface', whereas the simulator can be utilized as an advanced bio-tribometer. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Three-phase bone scan and indium white blood cell scintigraphy following porous coated hip arthroplasty: A prospective study of the prosthetic tip

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Oswald, S.G.; Van Nostrand, D.; Savory, C.G.

    1989-08-01

    Although few reports address the use of three-phase bone scanning (TPBS) and {sup 111}In-labeled white blood cell (In-WBC) scintigraphy in hip arthroplasty utilizing a porous coated prosthesis, the literature suggests that scintigraphic patterns in the uncomplicated patient may differ from that seen in the cemented prosthesis. In an attempt to determine the scintigraphic natural history, 25 uncomplicated porous coated hip arthroplasties in 21 patients were prospectively studied with serial TPBS and In-WBC at approximately 7 days, and at 3, 6, 12, 18, and 24 mo postoperatively. This report deals with findings related to the prosthetic tip. Only one of 136more » flow studies were abnormal and only two of 136 blood-pool images demonstrated focally increased activity. All 25 prostheses (120 of 143 scans) demonstrated increased uptake on the bone phase images. The area about the tip was divided into three segments; increased uptake at 24 mo was noted in the medial, distal, and lateral segments in 16%, 72%, and 56% of prostheses, respectively. Twenty of 25 prostheses (82 of 142 scans) showed uptake on In-WBC scintigraphy, being noted in 48% of prostheses at 24 mo. We conclude that scintigraphic patterns in the uncomplicated patient with a porous coated prosthesis appear to differ from patterns described in cemented prostheses.« less

  17. The acetabulum: A prospective study of three-phase bone and indium white blood cell scintigraphy following porous-coated hip arthroplasty

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Oswald, S.G.; Van Nostrand, D.; Savory, C.G.

    1990-03-01

    Although few studies address the use of three-phase bone scanning (TPBS) and indium-111-labeled white blood cell scintigraphy ({sup 111}In-WBC) in hip arthroplasty utilizing a porous-coated prosthesis, the literature suggests that scintigraphic patterns in the uncomplicated patient may differ from that seen with the cemented prosthesis. In an attempt to determine the scintigraphic natural history, 25 uncomplicated porous-coated hip arthroplasties in 21 patients were prospectively studied with serial TPBS and {sup 111I}n-WBC at approximately 7 days, and 3, 6, 12, 18, and 24 mo postoperatively. This report deals with findings related to the acetabulum. All 25 prostheses (144 of 144 scans)more » demonstrated increased uptake on the bone-phase images. Although this activity decreased with time, 76% had persistent uptake at 24 mo. Twenty-three of 25 prostheses (126 of 140 scans) showed increased uptake on {sup 111}In-WBC scintigraphy, invariably decreasing with time, but with 37% having significant uptake at 24 mo. Scintigraphic patterns in the uncomplicated porous-coated hip arthroplasty patient appear to differ from patterns described in cemented prostheses.« less

  18. Psoas abscess masquerading as a prosthetic hip infection: A case report.

    PubMed

    Atif, Muhammad; Malik, Azeem Tariq; Noordin, Shahryar

    2018-01-01

    Psoas abscess is an unusual condition and is defined as a collection of pus in the iliopsoas compartment. Due to the unique anatomy of psoas muscle it forms a conduit for spread of infection from upper part of body to hip joint in neglected cases. A 67year old lady presented with left groin pain for three weeks. She underwent an uncemented unipolar hemiarthoplasty eight years back. Currently, she developed fever and was unable to do any active left hip range of motion. Passive motion of the left hip was restricted to 30° flexion, no internal rotation, 5° external rotation, and 10° abduction. Lab workup showed raised serum infective markers and radiographs of pelvis were normal with no evidence of any radiolucency. Ultrasound guided aspiration of left hip joint showed E coli. Arthrotomy revealed clear fluid in hip joint but pus was drained at psoas insertion. Later on, culture reported presence of E. coli and biopsy confirmed psoas abscess. Postoperatively CT scan abdomen showed pyelonephritis. Antibiotics were given for three months. Twenty months later, she remains asymptomatic without evidence of infection with normal gait. Psoas abscess is a rare clinical entity that may mimic symptoms of a primary prosthetic hip infection. Treatment outcomes are directly related to early detection with adequate dissection of the psoas muscle up to sites of attachment and complete eradication of infection. This case highlights importance of thorough initial clinical examination, lab workup and radiological assessment to rule out rare causes of hip joint pain. Copyright © 2017. Published by Elsevier Ltd.

  19. The effect of total hip and hip resurfacing arthroplasty on vertical ground reaction force and impulse symmetry during a sit-to-stand task.

    PubMed

    Caplan, N; Stewart, S; Kashyap, S; Banaszkiewicz, P; St Clair Gibson, A; Kader, D; Ewen, A

    2014-12-01

    The aim of this study was to determine the influence of total hip arthroplasty and hip resurfacing arthroplasty on limb loading symmetry before, and after, hip reconstruction surgery during a sit-to-stand task. Fourteen patients were recruited that were about to receive either a total hip prosthesis (n=7) or a hip resurfacing prosthesis (n=7), as well as matched controls. Patients performed a sit-to-stand movement before, 3 months after, and 12 months after surgery. Peak vertical ground reaction force and impulse were measured for each leg, from which ground reaction force and impulse symmetry ratios were calculated. Before surgery, hip resurfacing patients showed a small asymmetry which was not different to normal for ground reaction force (0.88(0.28) vs. 1.00(0.11); p=0.311) or impulse (0.87(0.29) vs. 0.99(0.09); p=0.324) symmetry ratios. Total hip patients offloaded their affected hip by 30% in terms of impulse symmetry ratio (0.71(0.36) vs. 0.99(0.23); p=0.018). At 3 months following surgery asymmetries were seen that were different to normal in both hip resurfacing patients for ground reaction force (0.77(0.16); p=0.007), and total hip patients for ground reaction force (0.70(0.15); p=0.018) and impulse (0.72(0.16); p=0.011) symmetry ratios. By 12 months after surgery total hip patients regained a symmetrical loading pattern for both ground reaction force (0.95(0.06); p=0.676) and impulse (1.00(0.06); p=0.702) symmetry ratios. Hip resurfacing patients, however, performed the task by overloading their operated hip, with impulse symmetry ratio being larger than normal (1.16(0.16); p=0.035). Physiotherapists should appreciate the need for early recovery of limb loading symmetry as well as subsequent differences in the responses observed with different prostheses. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Revision Rates after Primary Hip and Knee Replacement in England between 2003 and 2006

    PubMed Central

    Sibanda, Nokuthaba; Copley, Lynn P; Lewsey, Jim D; Borroff, Mick; Gregg, Paul; MacGregor, Alex J; Pickford, Martin; Porter, Martyn; Tucker, Keith; van der Meulen, Jan H

    2008-01-01

    Background Hip and knee replacement are some of the most frequently performed surgical procedures in the world. Resurfacing of the hip and unicondylar knee replacement are increasingly being used. There is relatively little evidence on their performance. To study performance of joint replacement in England, we investigated revision rates in the first 3 y after hip or knee replacement according to prosthesis type. Methods and Findings We linked records of the National Joint Registry for England and Wales and the Hospital Episode Statistics for patients with a primary hip or knee replacement in the National Health Service in England between April 2003 and September 2006. Hospital Episode Statistics records of succeeding admissions were used to identify revisions for any reason. 76,576 patients with a primary hip replacement and 80,697 with a primary knee replacement were included (51% of all primary hip and knee replacements done in the English National Health Service). In hip patients, 3-y revision rates were 0.9% (95% confidence interval [CI] 0.8%–1.1%) with cemented, 2.0% (1.7%–2.3%) with cementless, 1.5% (1.1%–2.0% CI) with “hybrid” prostheses, and 2.6% (2.1%–3.1%) with hip resurfacing (p < 0.0001). Revision rates after hip resurfacing were increased especially in women. In knee patients, 3-y revision rates were 1.4% (1.2%–1.5% CI) with cemented, 1.5% (1.1%–2.1% CI) with cementless, and 2.8% (1.8%–4.5% CI) with unicondylar prostheses (p < 0.0001). Revision rates after knee replacement strongly decreased with age. Interpretation Overall, about one in 75 patients needed a revision of their prosthesis within 3 y. On the basis of our data, consideration should be given to using hip resurfacing only in male patients and unicondylar knee replacement only in elderly patients. PMID:18767900

  1. Morphological experimental study of bone stress at the interface acetabular bone/prosthetic cup in the bipolar hip prosthesis.

    PubMed

    Anuşca, D; Pleşea, I E; Iliescu, N; Tomescu, P; Poenaru, F; Dascălu, V; Pop, O T

    2006-01-01

    By calculating the tension and distortion of the elements composing the bipolar prosthesis under extreme conditions encountered in real life using a special post-processing program, we established the variation curves of the contact pressure at the hip bone-cup, armor-cup and cup-femoral head interface. By comparing the data obtained from all the examined cases, important conclusions were drawn regarding the influence of tension and pressure distribution on the structural integrity and biomechanics of the prosthesis, as well as the acetabular wear and tear, in order to assess its reliability. The experimentally determined tension and distortion status at the acetabular bone-metal armour interface, lead to the wear and tear phenomenon, which can be explained by three mechanisms and theories incompletely reflecting the overall process. The histopathologic study of the acetabular bone tissue using FEM (finite elements method) on surgically removed specimens will probably lead to the identification of a series of factors that could reduce the rate of the wear and tear process.

  2. Short-Term Effect of Prosthesis Transforming Sensory Modalities on Walking in Stroke Patients with Hemiparesis

    PubMed Central

    Sekiguchi, Yusuke; Honda, Keita; Ishiguro, Akio

    2016-01-01

    Sensory impairments caused by neurological or physical disorders hamper kinesthesia, making rehabilitation difficult. In order to overcome this problem, we proposed and developed a novel biofeedback prosthesis called Auditory Foot for transforming sensory modalities, in which the sensor prosthesis transforms plantar sensations to auditory feedback signals. This study investigated the short-term effect of the auditory feedback prosthesis on walking in stroke patients with hemiparesis. To evaluate the effect, we compared four conditions of auditory feedback from plantar sensors at the heel and fifth metatarsal. We found significant differences in the maximum hip extension angle and ankle plantar flexor moment on the affected side during the stance phase, between conditions with and without auditory feedback signals. These results indicate that our sensory prosthesis could enhance walking performance in stroke patients with hemiparesis, resulting in effective short-term rehabilitation. PMID:27547456

  3. Duration and frequency of every day activities in total hip patients.

    PubMed

    Morlock, M; Schneider, E; Bluhm, A; Vollmer, M; Bergmann, G; Müller, V; Honl, M

    2001-07-01

    Little knowledge about frequency and duration of daily activities in patients after total hip arthroplasty is available. Such information is required for the definition of realistic load collectives for pre-clinical testing of prostheses. It could also be helpful for the quantitative evaluation of surgery outcome with different prosthesis types. The purpose of this study was to develop and apply a system for the determination of frequency and duration of patient activities in their habitual environment and to compare the results to a clinical outcome score (Harris hip score).A portable activity monitoring system (weight 1.6 kg including batteries) was designed using a Palm top computer, 2 inclination sensors for the thigh and calf and one goniometer positioned at the knee joint. An algorithm was developed to identify frequency and duration of the activities lying, sitting, standing, walking and stair climbing from the signals of the 3 sensors. 42 patients participated in the study and were equipped with the system in the morning at their home. Datasets of 31 patients (age 62.5+/-11.5 y) covered more than 6h (9.8 +/- 1.6 h) and were included in the analysis. Prosthesis specific data as well as the Harris hip score were collected. The most frequent patient activity was sitting (44.3% of the time), followed by standing (24.5%), walking (10.2%), lying (5.8%) and stair climbing (0.4%). The median number of steps/stairs was 6048/164. The number of step cycles representing one year in vivo use should, consequently, be increased to 1.1 million. The Harris hip score (91.4 +/- 9.8) correlated significantly with the number of stairs (r(2) = 0.26, p = 0.003) and showed a positive tendency with the number of steps per day. No differences in activity levels between prosthesis specific factors were found.

  4. Good results in postoperative and hematogenous deep infections of 89 stable total hip and knee replacements with retention of prosthesis and local antibiotics.

    PubMed

    Geurts, Jan A P; Janssen, Daniël M C; Kessels, Alfons G H; Walenkamp, Geert H I M

    2013-12-01

    Deep postoperative and hematogenous prosthesis infections may be treated with retention of the prosthesis, if the prosthesis is stable. How long the infection may be present to preclude a good result is unclear. We retrospectively studied 89 deep-infected stable prostheses from 69 total hip replacements and 20 total knee replacements. There were 83 early or delayed postoperative infections and 6 hematogenous. In the postoperative infections, treatment had started 12 days to 2 years after implantation. In the hematogenous infections, symptoms had been present for 6 to 9 days. The patients had been treated with debridement, prosthesis retention, systemic antibiotics, and local antibiotics: gentamicin-PMMA beads or gentamicin collagen fleeces. The minimum follow-up time was 1.5 years. We investigated how the result of the treatment had been influenced by the length of the period the infection was present, and by other variables such as host characteristics, infection stage, and type of bacteria. In postoperative infections, the risk of failure increased with a longer postoperative interval: from 0.2 (95% CI: 0.1-0.3) if the treatment had started ≥ 4 weeks postoperatively to 0.5 (CI: 0.2-0.8) if it had started at ≥ 8 weeks. The relative risk for success was 0.6 (CI: 0.3-0.95) if the treatment had started ≥ 8 weeks. In the hematogenous group, 5 of 6 infections had been treated successfully. A longer delay before the start of the treatment caused an increased failure rate, but this must be weighed against the advantage of keeping the prosthesis. We consider a failure rate of < 50% to be acceptable, and we therefore advocate keeping the prosthesis for up to 8 weeks postoperatively, and in hematogenous infections with a short duration of symptoms.

  5. Revision hip arthroplasty with an extensively 
porous-coated stem - excellent long-term 
results also in severe femoral bone stock loss.

    PubMed

    Thomsen, Per B; Jensen, Niels J F; Kampmann, Jens; Bæk Hansen, Torben

    2013-01-01

    During the last 25 years uncemented hip stem revision relying on diaphyseal fixation has shown improving clinical results and stem survival. The purpose of this study was to present the long-term results of hip revision with the SOLUTION stem (DePuy, Warsaw Indiana).
Ninety-three consecutive SOLUTION hip stem revisions in 84 patients with a mean age of 69 years (range 33-86 years) were reviewed. Of these, clinical and radiographic follow-up examination by an independent observer was possible in 36 hips/29 patients after mean 14 years (range 10-18 years). Stem re-revision was documented by our own files and by the Danish Hip Arthroplasty Registry. 
Stem re-revision had been performed in two hips for aseptic loosening, one due to deep infection and in one patient due to stem fracture. The 18 years cumulative survival, free of re-revision for any reason was calculated as 94.4% (88.9-99.8)% and for aseptic loosening to 97.6% (94.3-100%). Intraoperative complications were frequent with incidence of shaft fractures (14/93) and perforations (9/93) showing a significant learning curve. Mean Harris Hip Score was 85 (range 53-99). Osseointegration was seen in 34/36 stems with two stems fibrous fixated. Stress shielding was significant associated with stem diameters ≥15 mm. Severe preoperative bone deficiency had no negative bearing on stem survival and no significant influence on osseointegration of the stem or on Harris Hip Score. 
 Femoral stem revision with an extensively porous-coated monoblock chrome-cobalt stem seems to be a reliable and reproducible technique resulting in excellent long-term survivorship and clinical outcome. It can be used in femurs with deficient bone stock.

  6. MANAGEMENT OF BILATERAL FEMORAL NECK FRACTURE IN A NONAGENARIAN PATIENT--CASE REPORT.

    PubMed

    Popescu, D; Trandabaţ, C; Puha, B; Veliceasa, B; Alexa, O

    2016-01-01

    Simultaneous bilateral femoral neck fracture is rare injury. Cases with this type of fracture have been reported in the literature since the 1950s, following the introduction of electroconvulsive therapy which generates violent hip muscle contractions. In young patients' simultaneous bilateral femoral neck fracture results from high energy trauma (car accident or fall from height) in a normal bone. Pathological changes in bone structure occurring in chronic kidney disease, vitamin D deficiency, osteomalacia, osteoporosis, metabolic imbalances and administration of corticosteroids explain the occurrence of this particular type of fracture following low-energy trauma. We present the case of a 90-year-old female patient who suffered a simple fall from her own height resulting in a Garden IV bilateral femoral neck fracture. Our therapeutic option in this patient was bilateral uncemented bipolar hemiarthroplasty in a single session using a single tray of sterile surgical instruments and two sterile drapes. Postoperative outcome was very good, allowing the initiation of functional recovery on the first postoperative day. Uncemented hemiarthroplasty proved to be a good choice in such a patient in the associated diseases may trigger the risk of cardiovascular disturbances specific to bone cement implantation syndrome.

  7. Proximal femoral bone loss and increased rate of fracture with a proximally hydroxyapatite-coated femoral component.

    PubMed

    Radl, R; Aigner, C; Hungerford, M; Pascher, A; Windhager, R

    2000-11-01

    We performed a retrospective analysis of the clinical and radiological outcomes of total hip replacement using an uncemented femoral component proximally coated with hydroxyapatite. Of 136 patients, 118 who had undergone 124 primary total hip replacements were available for study. Their mean age was 66.5 years (19 to 90) and the mean follow-up was 5.6 years (4.25 to 7.25). At the final follow-up the mean Harris hip score was 92 (47.7 to 100). Periprosthetic femoral fractures, which occurred in seven patients (5.6%), were treated by osteosynthesis in six and conservatively in one. We had to revise five femoral components, one because of aseptic loosening, one because of septic loosening and three because of periprosthetic fracture. At the final follow-up there were definite signs of aseptic loosening in two patients. Radiologically, proximal femoral bone loss in Gruen zones I and VI was evident in 96.8% of hips, while bone hypertrophy in zones III and V was seen in 64.7%. In 24 hips (20.2%) the mean subsidence of the stem was 3.7 mm which occurred within the first 12 postoperative weeks. This indicated poor initial stability, which might have been aggravated by early weight-bearing. The high rate of failure in our study suggests that proximal femoral bone loss affects the long-term survival of the replacement.

  8. The cost analysis of cemented versus cementless total hip replacement operations on the NHS.

    PubMed

    Kallala, R; Anderson, P; Morris, S; Haddad, F S

    2013-07-01

    In a time of limited resources, the debate continues over which types of hip prosthesis are clinically superior and more cost-effective. Orthopaedic surgeons increasingly need robust economic evidence to understand the full value of the operation, and to aid decision making on the 'package' of procedures that are available and to justify their practice beyond traditional clinical preference. In this paper we explore the current economic debate about the merits of cemented and cementless total hip replacement, an issue that continues to divide the orthopaedic community.

  9. Simulated studies of wear and friction in total hip prosthesis components with various ball sizes and surface finishes

    NASA Technical Reports Server (NTRS)

    Swikert, M. A.; Johnson, R. L.

    1976-01-01

    Experiments were conducted on a newly designed total hip joint simulator. The apparatus closely simulates the complex motions and loads of the human hip in normal walking. The wear and friction of presently used appliance configurations and materials were determined. A surface treatment of the metal femoral ball specimens was applied to influence wear. The results of the investigation indicate that wear can be reduced by mechanical treatment of metal femoral ball surfaces. A metallographic examination and surface roughness measurements were made.

  10. Interleukin-6 as an early marker for fat embolism

    PubMed Central

    Yoga, R; Theis, JC; Walton, M; Sutherland, W

    2009-01-01

    Background Fat Embolism is a complication of long bone fractures, intramedullary fixation and joint arthroplasty. It may progress to fat embolism syndrome, which is rare but involves significant morbidity and can occasionally be fatal. Fat Embolism can be detected at the time of embolization by transoesophageal echocardiography or atrial blood sampling. Later, a combination of clinical signs and symptoms will point towards fat embolism but there is no specific test to confirm the diagnosis. We investigated serum Interleukin-6 (IL-6) as a possible early marker for fat embolism. Methods An animal study was conducted to simulate a hip replacement in 31 adult male Sprague Dawley rats. The procedure was performed under general anesthesia and the animals divided into 3 groups: control, uncemented and cemented. Following surgery and recovery from anaesthesia, the rats allowed to freely mobilize in their cages. Blood was taken before surgery and at 6 hours, 12 hours and 24 hours to measure serum IL-6 levels. The rats were euthanized at 24 hours and lungs removed and stained for fat. The amount of fat seen was then correlated with serum IL-6 levels. Results No rats in the control group had fat emboli. Numerous fat emboli were seen in both the uncemented and cemented implant groups. The interleukin levels were raised in all groups reaching a peak at 12 hours after surgery reaching 100 pg/ml in the control group and around 250 pg/ml in the uncemented and cemented implant groups. The IL-6 levels in the control group were significantly lower than any of the implant groups at 12 and 24 hours. At these time points, the serum IL-6 correlated with the amount of fat seen on lung histology. Conclusion Serum IL-6 is a possible early marker of fat embolism. PMID:19523233

  11. Meta-analysis of individual registry results enhances international registry collaboration.

    PubMed

    Paxton, Elizabeth W; Mohaddes, Maziar; Laaksonen, Inari; Lorimer, Michelle; Graves, Stephen E; Malchau, Henrik; Namba, Robert S; Kärrholm, John; Rolfson, Ola; Cafri, Guy

    2018-03-28

    Background and purpose - Although common in medical research, meta-analysis has not been widely adopted in registry collaborations. A meta-analytic approach in which each registry conducts a standardized analysis on its own data followed by a meta-analysis to calculate a weighted average of the estimates allows collaboration without sharing patient-level data. The value of meta-analysis as an alternative to individual patient data analysis is illustrated in this study by comparing the risk of revision of porous tantalum cups versus other uncemented cups in primary total hip arthroplasties from Sweden, Australia, and a US registry (2003-2015). Patients and methods - For both individual patient data analysis and meta-analysis approaches a Cox proportional hazard model was fit for time to revision, comparing porous tantalum (n = 23,201) with other uncemented cups (n = 128,321). Covariates included age, sex, diagnosis, head size, and stem fixation. In the meta-analysis approach, treatment effect size (i.e., Cox model hazard ratio) was calculated within each registry and a weighted average for the individual registries' estimates was calculated. Results - Patient-level data analysis and meta-analytic approaches yielded the same results with the porous tantalum cups having a higher risk of revision than other uncemented cups (HR (95% CI) 1.6 (1.4-1.7) and HR (95% CI) 1.5 (1.4-1.7), respectively). Adding the US cohort to the meta-analysis led to greater generalizability, increased precision of the treatment effect, and similar findings (HR (95% CI) 1.6 (1.4-1.7)) with increased risk of porous tantalum cups. Interpretation - The meta-analytic technique is a viable option to address privacy, security, and data ownership concerns allowing more expansive registry collaboration, greater generalizability, and increased precision of treatment effects.

  12. Total hip arthroplasty survival in femoral head avascular necrosis versus primary hip osteoarthritis: Case-control study with a mean 10-year follow-up after anatomical cementless metal-on-metal 28-mm replacement.

    PubMed

    Ancelin, D; Reina, N; Cavaignac, E; Delclaux, S; Chiron, P

    2016-12-01

    Total hip arthroplasty is the most widely used procedure to treat avascular necrosis (AVN) of the femoral head. Few studies have compared the outcomes of THA in femoral head AVN and primary hip osteoarthritis. Therefore we performed a case-control study to compare THA for femoral head AVN vs. primary hip osteoarthritis in terms of: (1) prosthesis survival, (2) complication rates, (3) functional outcomes and radiographic outcomes, (4) and to determine whether specific risk factors for THA failure exist in femoral head AVN. THA survival is similar in femoral head AVN and primary hip osteoarthritis. We compared two prospective cohorts of patients who underwent THA before 65 years of age, one composed of cases with femoral head AVN and the other of controls with primary hip osteoarthritis. In both cohorts, a cementless metal-on-metal prosthesis with a 28-mm cup and an anatomical stem was used. Exclusion criteria were THA with other types of prosthesis, posttraumatic AVN, and secondary osteoarthritis. With α set at 5%, to obtain 80% power, 246 patients were required in all. Prosthesis survival was assessed based on time to major revision (defined as replacement of at least one implant fixed to bone) and time to aseptic loosening. The other evaluation criteria were complications, Postel-Merle d'Aubigné (PMA) score, and the Engh and Agora Radiographic Assessment (ARA) scores for implant osseointegration. The study included 282 patients, 149 with AVN and 133 with osteoarthritis. Mean age was 47.8±10.2 years (range, 18.5-65) and mean follow-up was 11.4±2.8 years (range, 4.5-18.3 years). The 10-year survival rates were similar in the two groups: for major revision, AVN group, 92.5% (95% confidence interval [95% CI], 90.2-94.8) and osteoarthritis group, 95.3% (95% CI, 92.9-97.7); for aseptic loosening, AVN group, 98.6% (95% CI, 97.6-98.6) and osteoarthritis, 99.2% (95% CI, 98.4-100). The AVN group had higher numbers of revision for any reason (19 vs. 6, P=0.018) and for dislocation (8 vs. 1, P=0.031). Mean PMA scores at last follow-up were comparable in the AVN group (17.65±1.27 [range, 10-18]) and osteoarthritis group (17.59±1.32 [range, 14-18]) (P=0.139). Osseointegration was also similar in the two groups: global Engh score, 26.51±1.81 (range, 14-27) for AVN and 26.84±0.91 (range, 19.5-27) for osteoarthritis (P=0.065); femoral ARA score, 5.83±0.46 (range, 3-6) for AVN and 5.90±0.42 (range, 3-6) for osteoarthritis (P=0.064); and cup ARA score, 5.74±0.67 (range, 3-6) for AVN and 5.78±0.66 (range, 3-6) for osteoarthritis (P=0.344). Survival in this study was good and consistent with recent data on AVN, with no difference between AVN and osteoarthritis. Revisions for any cause or for dislocation were more common after THA for AVN. Functional outcomes were similar in the AVN and osteoarthritis groups. An anatomical cementless prosthesis combined with metal-on-metal 28-mm bearing provides durable good outcomes. III, non-randomized comparison of two prospective cohorts. Published by Elsevier Masson SAS.

  13. Staged Reimplantation of a Total Hip Prosthesis After Co-infection with Candida tropicalis and Staphylococcus haemolyticus: A Case Report.

    PubMed

    Sebastian, Sujeesh; Malhotra, Rajesh; Pande, Ashish; Gautam, Deepak; Xess, Immaculata; Dhawan, Benu

    2018-06-01

    Fungal prosthetic joint infection is a rare complication in total joint arthroplasty. There are no established guidelines for management of these infections. We present a case of a 53-year-old male with a hip joint prosthesis co-infected with Candida tropicalis and Staphylococcus haemolyticus. A two-stage exchange arthroplasty was performed. The patient underwent implant removal, debridement, irrigation with saline solution and application of cement spacer impregnated with vancomycin followed by aggressive antimicrobial treatment in first stage. Complete eradication of infection was demonstrated by negative culture of sonicated cement spacer fluid and negative 16S rRNA and 18S rRNA gene PCR of sonicate fluid, synovial fluid and periprosthetic tissue samples. He underwent second-stage revision hip arthroplasty after 9 months of the first stage. At the latest follow-up, there was no evidence of recurrence of infection. This case illustrates the utility of sonication of biomaterials and molecular techniques for microbiological confirmation of absence of infection in staged surgeries which is required for a successful outcome.

  14. Stability of the Giliberty bipolar hip: report of three cases.

    PubMed

    Langan, P; Weiss, C A

    1978-01-01

    The Giliberty Bipolar Hip Prosthesis consists of an unbonded acetabular cup which snap-fits over the head of the femoral prosthesis. Because of the free movement permitted at the cup-pelvic junction as well as at the snap-fit interface, there has been a great deal of concern over the potential for dislocation. Three patients in whom this unit was implanted sustained significant skeletal trauma subsequent to surgery. None of them dislocated. In each case the prosthetic head was known to be in a relatively vertical orientation with respect to the transverse axis of the pelvis prior to the injury. In 2 of the 3 cases radiographically identifiable movement of the cup was present before and after the injury. These observations suggest that the persistently mobile, vertically positioned unbonded cup remain stable despite the stress of significant trauma. It is probable that the potential for cup movement, even where on the X-ray it appears to have stopped, acts as a safety valve in absorbing force that might otherwise dislocate the hip or cause fractures of the femur or the pelvis.

  15. Design aspects and clinical performance of the thrust plate hip prosthesis.

    PubMed

    Jacob, H A C; Bereiter, H H; Buergi, M L

    2007-01-01

    The thrust plate hip prosthesis (TPP) was conceived to maintain the physiological stress distribution in the proximal femur so as to prevent bone atrophy in this region, often encountered after implantation of conventional stem-type prostheses. A thrust plate of TiAlNb is firmly fixed to the neck of the femur by means of a forged CoCrMo bolt introduced through the lateral cortex, just below the greater trochanter, and through the metaphysis. A boss that contains the bolt head rests on the lateral cortex. A proximal extension from the thrust plate terminates in the ball head of the hip joint. Bone remodelling causes the initial prestressing of the structure (primary stability) to decline, but full integration of the thrust plate with the underlying host bone affords secondary stability. A total of 102 TPPs were implanted in the Cantonal Hospital, Chur, Switzerland, from 1992 to 1999 in 84 patients. The TPP was selected particularly for patients of the younger age group (26-76). Through its ability to load the medial cortex of the proximal femur in a physiological manner, the cortical bone in this region is preserved. The mean Harris hip score is 97 points and the survival rate 98 per cent, 144 months post-operatively.

  16. [Treatment of periprosthetic femoral fractures after total hip arthroplasty with specially constructed retrograde hollow nails].

    PubMed

    Szalay, G; Meyer, C; Mika, J; Schnettler, R; Thormann, U

    2014-12-01

    Treatment of periprosthetic fractures by implantation of a specially constructed, retrograde hollow nail which fits over the tip of the prosthesis and becomes locked on it. Periprosthetic femoral fractures with firmly anchored prosthesis shaft after total hip arthroplasty of types B1 and C according to the Vancouver classification. Loosened prosthesis (type B2/B3) and trochanteric fractures (type A). Broken or damaged prosthesis, florid inflammation and soft tissue injuries in the operation field, contracted knee joint, advanced deformation in the knee joint and distal femur, enclosed prosthesis and general contraindications. In a supine position the periprosthetic fracture is exposed via a lateral access. For cemented prostheses the cement is removed around the tip of the prosthesis (at least 2-3 cm) and medullary cavity. Arthrotomy with flexion of the knee joint and marking of the nail entry point. Drill the medullary cavity, retrograde introduction of the nail, visually fit the nail over the tip of the prosthesis and lock the nail with the prosthesis. If necessary use additional spongiosaplasty or also placement of additional cerclages depending on fracture type and size of the defect zone. Lock the nail distally. Use intraoperative radiological imaging to control correct positioning and length of the nail. Close the wound layer by layer with placement of suction drainage devices and dressing. Partial loading for 6 weeks with a subsequent pain-adapted loading gradient until full loading is possible. If selective partial loading is not possible, a decision must be made in individual cases as to whether the intraoperative findings allow immediate full loading. From 2004 to 2011 a total of 25 periprosthetic femoral fractures in 25 patients were treated in 2 locations using specially constructed slotted hollow nails. Within the framework of a retrospective study 20 of these patients (16 female and 4 male; average age 77.2 [72-84] years) were clinically and radiologically re-examined on average 19.3 (7-31) months postoperatively. No postoperative bleeding, wound healing disorders and infections. In all patients there was a loading stable consolidation of the fracture in the correct femoral axis, length and rotation with no evidence for radiological signs of loosening of the prosthesis or dislocation of the nails. In one case there was loosening of the prosthesis which had obviously occurred during the operative procedure. After consolidation of the fracture it was necessary to exchange the prosthesis for a long shafted prosthesis. A comparable situation to the preoperative degree of mobility was found in 12 out of the 20 patients, a moderate deterioration in 5 patients, a substantial residual impairment in 2 patients and an improvement of the situation in 1 patient.

  17. /sup 99m/Tc-methylene diphosphonate bone imaging in the evaluation of total hip prostheses

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Weiss, P.E.; Mall, J.C.; Hoffer, P.B.

    1979-12-01

    A retrospective study was performed to determine the accuracy of /sup 99m/Tc-methylene diphosphonate bone imaging in the evaluation of total hip arthroplasty for loosening and/or infection. Using focally increased activity at the tip of the femoral component or in the region of the acetabular component as a criterion, the examination was 77% specific and 100% sensitive for loosening and/or infection. A possible explanation for the increased uptake at the tip of the femoral component and the role of this examination in the management of a painful total hip prosthesis are discussed.

  18. Measurement of installation deformation of the acetabulum during prosthetic replacement of a hip joint using digital image correlation

    NASA Astrophysics Data System (ADS)

    Lei, Dong; Bai, Pengxiang; Zhu, Feipeng

    2018-01-01

    Nowadays, acetabulum prosthesis replacement is widely used in clinical medicine. However, there is no efficient way to evaluate the implantation effect of the prosthesis. Based on a modern photomechanics technique called digital image correlation (DIC), the evaluation method of the installation effect of the acetabulum was established during a prosthetic replacement of a hip joint. The DIC method determines strain field by comparing the speckle images between the undeformed sample and the deformed counterpart. Three groups of experiments were carried out to verify the feasibility of the DIC method on the acetabulum installation deformation test. Experimental results indicate that the installation deformation of acetabulum generally includes elastic deformation (corresponding to the principal strain of about 1.2%) and plastic deformation. When the installation angle is ideal, the plastic deformation can be effectively reduced, which could prolong the service life of acetabulum prostheses.

  19. Iliopsoas tendon rupture: a new differential for atraumatic groin pain post-total hip arthroplasty.

    PubMed

    Piggott, Robert Pearse; Doody, Orla; Quinlan, John Francis

    2015-02-26

    Groin pain post-total hip arthroplasty (THA) is of concern for the patient and the surgeon, especially when there is no history of any traumatic event. Obvious concern centres on complications from the prosthesis. The use of multiple imaging modalities allow for accurate diagnosis of groin pain. Atraumatic iliopsoas rupture is rare and has only been reported once before in the setting of THA. We present the case of 53-year old female with atraumatic rupture of the iliopsoas tendon that presented with severe groin pain and limited flexion. We discuss the clinical presentation, radiological features and follow-up of the patient. We also discuss the relevant published literature on the topic. This is a rare phenomenon but should be consider in patients with groin pain post-THA, especially after prosthesis complications have been ruled out. 2015 BMJ Publishing Group Ltd.

  20. The effect of changing the inertia of a trans-tibial dynamic elastic response prosthesis on the kinematics and ground reaction force patterns.

    PubMed

    Hillery, S C; Wallace, E S; McIlhagger, R; Watson, P

    1997-08-01

    The aim of this study was to assess, by means of gait analysis, the effect on the gait of a trans-tibial amputee of altering the mass and the moment of inertia of a dynamic elastic response prosthesis. One male amputee was analysed for four to five walking trials at normal and fast cadences, using the VICON system of motion analysis and an AMTI force plate. The kinematic variables of cadence, swing time, single support time and joint angles for the knee and hip on the affected and intact sides were analysed. The ground reaction force was also analysed. The sample size was limited to one as an example to indicate the changes which are possible through simply changing the inertial characteristics. Descriptive statistics are used to demonstrate these changes. Three mass conditions for the prosthesis were analysed m1: 1080g; m2: 1080 + 530g; m3: 1080 + 1460g. The m1 condition is the mass of the prosthesis with no added weight while m2 and m3 were attachments of the same geometrical shape but were made from different materials. It was felt that the large mass range would highlight biomechanical adjustments as a result of its alteration. The effect on selected temporal characteristics were that as the speed increased the cadence changed and the affected side single support times as a percentage of the gait cycle were altered. The effect on the joint angles was also apparent at the hip and knee of both sides. The ground reaction force patterns were similar for all three mass conditions, though the impact peak which was evident in the intact limb was missing, indicating a shock absorbing property in the prosthesis. Clearly, changing the mass and moment of inertia has an effect on the kinematic variables of gait and should be considered when designing a prosthesis.

  1. Numerical simulation of artificial hip joint motion based on human age factor

    NASA Astrophysics Data System (ADS)

    Ramdhani, Safarudin; Saputra, Eko; Jamari, J.

    2018-05-01

    Artificial hip joint is a prosthesis (synthetic body part) which usually consists of two or more components. Replacement of the hip joint due to the occurrence of arthritis, ordinarily patients aged or older. Numerical simulation models are used to observe the range of motion in the artificial hip joint, the range of motion of joints used as the basis of human age. Finite- element analysis (FEA) is used to calculate stress von mises in motion and observes a probability of prosthetic impingement. FEA uses a three-dimensional nonlinear model and considers the position variation of acetabular liner cups. The result of numerical simulation shows that FEA method can be used to analyze the performance calculation of the artificial hip joint at this time more accurate than conventional method.

  2. Total Hip Arthroplasty Using a Polished Tapered Cemented Stem in Hereditary Multiple Exostosis

    PubMed Central

    Kanda, Akio; Kaneko, Kazuo; Obayashi, Osamu; Mogami, Atsuhiko

    2016-01-01

    A 61-year-old Japanese man underwent right total hip arthroplasty for hereditary multiple exostosis. At first presentation, he had suffered from coxalgia for a long time. On radiographic images, there was a gigantic femoral head, increased shaft angle, and large diameter of the femoral neck. He had also developed coxarthrosis and severe pain of the hip joint. The transformation of the proximal femur bone causes difficulty in setting a cementless total hip prosthesis. Therefore, total hip arthroplasty using a cemented polished tapered stem was performed via a direct lateral approach. Using a cemented polished tapered stem allowed us to deal with the femoral bone transformation and bone substance defectiveness due to exostosis and also minimized the invasiveness of the operation. PMID:27127668

  3. The Morscher Press-Fit Acetabular Component: An Independent Long-Term Review at 18-22 Years.

    PubMed

    Gwynne-Jones, David P; Lash, Heath W R; James, Andrew W; Iosua, Ella E; Matheson, John A

    2017-08-01

    There are relatively few 20-year results of uncemented acetabular components, and most of these are modular designs. This study reports the 20-year results of a monoblock press-fit acetabular component. A total of 122 total hip arthroplasties (111 patients) using the Morscher cup were reviewed at a mean of 19.7 years. The average age at implantation was 57.3 years (range, 36-74 years), and 81 (66%) were men. Twenty-two patients (25 hips) had died. Seven hips were revised, including 5 acetabular revisions. Six patients (6 hips) declined to participate but were known not to have been revised. The mean Oxford hip score was 41.1 (range, 22-48), and the mean reduced Western Ontario and McMaster Universities Osteoarthritis Index score was 5.7/48 (range, 0-24). Eccentric wear was seen in 13 (15.7%) and major osteolysis in 14 (17%) of 82 surviving hips with radiographs. The all-cause revision rate was 0.32 per 100 observed component years (95% confidence interval [CI], 0.13-0.66). The 20-year Kaplan-Meier survival was 93.4% (CI, 86.6-96.8) for all-cause revisions, 95.5% (CI, 89.4-98.1) for any acetabular revision, and 97.1% (CI, 91.2-99.1) for acetabular aseptic loosening, wear, or osteolysis. The Morscher acetabular component has continued to perform well at 20 years despite using conventional polyethylene with results that match or surpass other cementless acetabulae. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Abdullah, Abdul Halim; Nor, Mohd Asri Mohd; Saman, Alias Mohd

    Aseptic loosening effects are critical issues in encouraging long term stability of cemented hip arthroplasty. Stress shielding is believed to be an important factor that contributes to the aseptic loosening problems. The numerous changes in the prosthesis stem design are intended to minimize the stress shielding and aseptic loosening problems and to improve the long term performance of the implants. In this study, the stress distribution in cemented hip arthroplasty is established using finite element method. The taper of the prosthesis is designed to be 3 deg. at anterior/posterior, 3 deg. at medial/lateral and 10 deg. from wide lateral tomore » narrow medial. Major muscle loads and contact forces are simulated for walking (toe-off phase) and stair climbing load cases. Effects of prosthesis stem tapers on the resulting stress distribution are investigated. Results show that compressive stress dominates in the medial plane while tensile stress in the lateral plane of the femur. The corresponding stress levels of intact femur for walking and stair-climbing load cases are 22 and 29 MPa, respectively. The magnitude of Tresca stress for the THA femur in stair-climbing load case remains higher in the region of 85 MPa while the walking load case induces around 40 MPa. The stress range in the straight and single taper stem prosthesis is lower than 260 MPa, while localized Tresca stress is in the order of the yield strength of Ti-6Al-4V alloy for double and triple taper stem design.« less

  5. Virtual prototyping of a semi-active transfemoral prosthetic leg.

    PubMed

    Lui, Zhen Wei; Awad, Mohammed I; Abouhossein, Alireza; Dehghani-Sanij, Abbas A; Messenger, Neil

    2015-05-01

    This article presents a virtual prototyping study of a semi-active lower limb prosthesis to improve the functionality of an amputee during prosthesis-environment interaction for level ground walking. Articulated ankle-foot prosthesis and a single-axis semi-active prosthetic knee with active and passive operating modes were considered. Data for level ground walking were collected using a photogrammetric method in order to develop a base-line simulation model and with the hip kinematics input to verify the proposed design. The simulated results show that the semi-active lower limb prosthesis is able to move efficiently in passive mode, and the activation time of the knee actuator can be reduced by approximately 50%. Therefore, this semi-active system has the potential to reduce the energy consumption of the actuators required during level ground walking and requires less compensation from the amputee due to lower deviation of the vertical excursion of body centre of mass. © IMechE 2015.

  6. Monaco and film dosimetry of 3D CRT, IMRT and VMAT cases in a realistic pelvic prosthetic phantom

    NASA Astrophysics Data System (ADS)

    Ade, Nicholas; du Plessis, F. C. P.

    2018-04-01

    The dosimetry of patients with metallic hip implants during irradiation of pelvic lesions is challenging due to dose distortions caused by implants. This work presents a dosimetric comparison of various multi-field photon-beam dose distributions in the presence of unilateral hip titanium prosthesis (UHTiP) embedded in a unique pelvic phantom made out of water-equivalent nylon slices. The impact of the UHTiP on the accuracy of dose calculations from a Monaco TPS (treatment planning system) using the X-ray voxel Monte Carlo (XVMC) algorithm was benchmarked against measured dose data using Gafchromic EBT3 film. Multi-field beam arrangements including a 4-field box, 5-field 3DCRT (three-dimensional conformal radiation therapy), 6-field IMRT (intensity modulated radiation therapy) and a single-arc VMAT (volumetric modulated arc therapy) plan were set up for 6 MV and 15 MV beams. These plans were generated for the pelvic phantom that contains the prosthesis with film inserted. Compared to Monaco TPS dose calculations, film measurements showed enhanced dose in the prosthesis which was not predicted by Monaco due to its limitation in relative density assignment. The enhanced prosthesis dose increased with increase in beam energy and decreased with the complexity of the treatment plans, with VMAT giving the least escalated dose. The dose increased between 5% and 19% for 6 MV and between 6% and 21% for 15 MV. A gamma index analysis showed that 70-92% of dose points (excluding the prosthesis) were within 3% discrepancy. Increasing the number of treatment fields increases target dose coverage and improves the agreement between film and Monaco. When the relative electron density (RED) in the prosthesis was varied between 3.72 and 15 the dose discrepancy between film and Monaco increased from 30% to 57% for 6 MV and from 30% to 50% for 15 MV. The study indicates that beam weights for fields that pass through the prosthesis should be minimised and its RED must be correct for accurate dose calculation on Monaco.

  7. Revision total hip arthroplasty: the femoral side using cemented implants.

    PubMed

    Holt, Graeme; Hook, Samantha; Hubble, Matthew

    2011-02-01

    Advances in surgical technique and implant technology have improved the ten-year survival after primary total hip arthroplasty (THA). Despite this, the number of revision procedures has been increasing in recent years, a trend which is predicted to continue into the future. Revision THA is a technically demanding procedure often complicated by a loss of host bone stock which may be compounded by the need to remove primary implants. Both cemented and uncemented implant designs are commonly used in the United Kingdom for primary and revision THA and much controversy still exists as to the ideal method of stem fixation. In this article we discuss revision of the femur using cemented components during revision THA. We focus on three clinical scenarios including femoral cement-in-cement revision where the primary femoral cement-bone interface remains well fixed, femoral cement-in-cement revision for peri-prosthetic femoral fractures, and femoral impaction grafting. We discuss the clinical indications, surgical techniques and clinical outcomes for each of these procedures.

  8. Gait rehabilitation for a patient with an osseointegrated prosthesis following transfemoral amputation.

    PubMed

    Leijendekkers, Ruud A; van Hinte, Gerben; Nijhuis-van der Sanden, Maria Wg; Staal, J Bart

    2017-02-01

    In patients with a transfemoral amputation socket-related problems are associated with reduced prosthetic use, activity, and quality of life. Furthermore, gait asymmetries are present that may explain secondary complaints. Bone-anchored prostheses (BAPs) may help these patients. Two types of BAP are available, screw and press-fit implants. Rehabilitation following surgery for a press-fit BAP is poorly described. To describe a rehabilitation program designed to minimize compensation strategies and increase activity using a case-report of an active, 70-year-old man with a traumatic transfemoral amputation who had used a socket prosthesis for 52 years and received a press-fit BAP [Endo-Exo Femoral Prosthesis - EEFP]. A 13-week physiotherapy program. Outcomes were assessed before surgery, at the end of rehabilitation, and six-month and one-year follow-ups. After rehabilitation gait had improved, the patient had more arm movement, more pelvic shift, less hip rotation during swing phase on the prosthetic side, and absence of vaulting on the sound side. Isometric hip abductor strength was 15% higher on the sound side and 16% higher on the prosthetic side, and walking distance increased from 200 m to 1500 m. At the six-month follow-up, the patient had lower back complications and reduced hip abductor strength and walking distance. At one-year follow-up, walking distance had recovered to 1000 m and gait pattern had improved again, with yielding and absence of terminal impact on the prosthetic side. The described rehabilitation program may be an effective method of improving gait in patients with an EEFP even after long-term socket usage.

  9. Hospital ownership: a risk factor for nosocomial infection rates?

    PubMed

    Schröder, C; Behnke, M; Geffers, C; Gastmeier, P

    2018-03-26

    In some countries, a relationship between hospital ownership and the occurrence of healthcare-associated infection (HCAI) rates has been described. To investigate the association between hospital ownership and occurrence of HCAI in Germany. Five different components of the German national nosocomial infection surveillance system were analysed with regard to the influence of hospital ownership in the period 2014-2016. Endpoints included ventilator-associated pneumonia, central-venous-catheter-associated bloodstream infections, urinary-catheter-associated urinary tract infections, surgical site infections (SSI) following hip prosthesis and colon surgery, meticillin-resistant Staphylococcus aureus (MRSA), Clostridium difficile infections (CDI) and hand rub consumption per 1000 patient-days. Three hospital ownership types (public, non-profit and private) were analysed using univariate and multi-variate methods. The distribution of hospitals according to the three ownership types was similar in all components. In total, 661 intensive care units (ICUs), 149 departments performing colon procedures, and 349 departments performing hip prosthesis were included. In addition, 568 hospitals provided their MRSA rates and 236 provided their CDI rates, and 1833 ICUs and 12,934 non-ICUs provided their hand rub consumption data. In general, the differences between the hospital types were rather small and not significant for the ICUs. In the multi-variate analysis, public hospitals had a lower SSI rate following hip prosthesis (odds ratio 0.80, 95% confidence interval 0.65-0.99). Hospital ownership was not found to have a major influence on the incidence of HCAI in Germany. Copyright © 2018 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  10. Short uncemented stems allow greater femoral flexibility and may reduce peri-prosthetic fracture risk: a dry bone and cadaveric study.

    PubMed

    Jones, Christopher; Aqil, Adeel; Clarke, Susannah; Cobb, Justin P

    2015-09-01

    Short femoral stems for uncemented total hip arthroplasty have been introduced as a safe alternative to traditional longer stem designs. However, there has been little biomechanical examination of the effects of stem length on complications of surgery. This study aims to examine the effect of femoral stem length on torsional resistance to peri-prosthetic fracture. We tested 16 synthetic and two paired cadaveric femora. Specimens were implanted and then rapidly rotated until fracture to simulate internal rotation on a planted foot, as might occur during stumbling. 3D planning software and custom-printed 3D cutting guides were used to enhance the accuracy and consistency of our stem insertion technique. Synthetic femora implanted with short stems fractured at a significantly higher torque (27.1 vs. 24.2 Nm, p = 0.03) and angle (30.3° vs. 22.3°, p = 0.002) than those implanted with long stems. Fracture patterns of the two groups were different, but showed remarkable consistency within each group. These characteristic fracture patterns were closely replicated in the pair of cadaveric femora. This new short-stemmed press-fit femoral component allows more femoral flexibility and confers a higher resistance to peri-prosthetic fracture from torsional forces than long stems.

  11. Position of the prosthesis and the incidence of dislocation following total hip replacement.

    PubMed

    He, Rong-xin; Yan, Shi-gui; Wu, Li-dong; Wang, Xiang-hua; Dai, Xue-song

    2007-07-05

    Dislocation is the second most common complication of hip replacement surgery, and impact of the prosthesis is believed to be the fundamental reason. The present study employed Solidworks 2003 and MSC-Nastran software to analyze the three dimensional variables in order to investigate how to prevent dislocation following hip replacement surgery. Computed tomography (CT) imaging was used to collect femoral outline data and Solidworks 2003 software was used to construct the cup model with variabilities. Nastran software was used to evaluate dislocation at different prosthesis positions and different geometrical shapes. Three dimensional movement and results from finite element method were analyzed and the values of dislocation resistance index (DRI), range of motion to impingement (ROM-I), range of motion to dislocation (ROM-D) and peak resisting moment (PRM) were determined. Computer simulation was used to evaluate the range of motion of the hip joint at different prosthesis positions. Finite element analysis showed: (1) Increasing the ratio of head/neck increased the ROM-I values and moderately increased ROM-D and PRM values. Increasing the head size significantly increased PRM and to some extent ROM-I and ROM-D values, which suggested that there would be a greater likelihood of dislocation. (2) Increasing the anteversion angle increased the ROM-I, ROM-D, PRM, energy required for dislocation (ENERGY-D) and DRI values, which would increase the stability of the joint. (3) As the chamber angle was increased, ROM-I, ROM-D, PRM, Energy-D and DRI values were increased, resulting in improved joint stability. Chamber angles exceeding 55 degrees resulted in increases in ROM-I and ROM-D values, but decreases in PRM, Energy-D, and DRI values, which, in turn, increased the likelihood of dislocation. (4) The cup, which was reduced posteriorly, reduced ROM-I values (2.1 -- 5.3 degrees ) and increased the DRI value (0.073). This suggested that the posterior high side had the effect of 10 degrees anteversion angle. Increasing the head/neck ratio increases joint stability. Posterior high side reduced the range of motion of the joint but increased joint stability; Increasing the anteversion angle increases DRI values and thus improve joint stability; Increasing the chamber angle increases DRI values and improves joint stability. However, at angles exceeding 55 degrees , further increases in the chamber angle result in decreased DRI values and reduce the stability of the joint.

  12. Total Hip Joint Replacement Biotelemetry System

    NASA Technical Reports Server (NTRS)

    Boreham, J. F.; Postal, R. B.; Luntz, R. A.

    1981-01-01

    The development of a biotelemetry system that is hermetically sealed within a total hip replacement implant is reported. The telemetry system transmits six channels of stress data to reconstruct the major forces acting on the neck of the prosthesis and uses an induction power coupling technique to eliminate the need for internal batteries. The activities associated with the telemetry microminiaturization, data recovery console, hardware fabrications, power induction systems, electrical and mechanical testing and hermetic sealing test results are discussed.

  13. Articulating spacers used in two-stage revision of infected hip and knee prostheses abrade with time.

    PubMed

    Fink, Bernd; Rechtenbach, Annett; Büchner, Hubert; Vogt, Sebastian; Hahn, Michael

    2011-04-01

    Articulating spacers used in two-stage revision surgery of infected prostheses have the potential to abrade and subsequently induce third-body wear of the new prosthesis. We asked whether particulate material abraded from spacers could be detected in the synovial membrane 6 weeks after implantation when the spacers were removed for the second stage of the revision. Sixteen hip spacers (cemented prosthesis stem articulating with a cement cup) and four knee spacers (customized mobile cement spacers) were explanted 6 weeks after implantation and the synovial membranes were removed at the same time. The membranes were examined by xray fluorescence spectroscopy, xray diffraction for the presence of abraded particles originating from the spacer material, and analyzed in a semiquantitative manner by inductively coupled plasma mass spectrometry. Histologic analyses also were performed. We found zirconium dioxide in substantial amounts in all samples, and in the specimens of the hip synovial lining, we detected particles that originated from the metal heads of the spacers. Histologically, zirconium oxide particles were seen in the synovial membrane of every spacer and bone cement particles in one knee and two hip spacers. The observations suggest cement spacers do abrade within 6 weeks. Given the presence of abrasion debris, we recommend total synovectomy and extensive lavage during the second-stage reimplantation surgery to minimize the number of abraded particles and any retained bacteria.

  14. Rapid Molecular Microbiologic Diagnosis of Prosthetic Joint Infection

    PubMed Central

    Cazanave, Charles; Greenwood-Quaintance, Kerryl E.; Hanssen, Arlen D.; Karau, Melissa J.; Schmidt, Suzannah M.; Gomez Urena, Eric O.; Mandrekar, Jayawant N.; Osmon, Douglas R.; Lough, Lindsay E.; Pritt, Bobbi S.; Steckelberg, James M.

    2013-01-01

    We previously showed that culture of samples obtained by prosthesis vortexing and sonication was more sensitive than tissue culture for prosthetic joint infection (PJI) diagnosis. Despite improved sensitivity, culture-negative cases remained; furthermore, culture has a long turnaround time. We designed a genus-/group-specific rapid PCR assay panel targeting PJI bacteria and applied it to samples obtained by vortexing and sonicating explanted hip and knee prostheses, and we compared the results to those with sonicate fluid and periprosthetic tissue culture obtained at revision or resection arthroplasty. We studied 434 subjects with knee (n = 272) or hip (n = 162) prostheses; using a standardized definition, 144 had PJI. Sensitivities of tissue culture, of sonicate fluid culture, and of PCR were 70.1, 72.9, and 77.1%, respectively. Specificities were 97.9, 98.3, and 97.9%, respectively. Sonicate fluid PCR was more sensitive than tissue culture (P = 0.04). PCR of prosthesis sonication samples is more sensitive than tissue culture for the microbiologic diagnosis of prosthetic hip and knee infection and provides same-day PJI diagnosis with definition of microbiology. The high assay specificity suggests that typical PJI bacteria may not cause aseptic implant failure. PMID:23658273

  15. [Diagnosis of septic loosening of hip prosthesis with LeukoScan. SPECT scan with 99mTc-labeled monoclonal antibodies].

    PubMed

    Kaisidis, A; Megas, P; Apostolopoulos, D; Spiridonidis, T; Koumoundourou, D; Zouboulis, P; Lambiris, E; Vassilakos, P

    2005-05-01

    Diagnosis of septic loosening of hip endoprosthesis with antigranulocyte scintigraphy (AGS) was analysed. Twenty-one hip prostheses were studied using laboratory tests and, in cases of elevated values, three-phase bone scan (BS) and AGS. Elective SPECT/CT scans were performed. Histologic and microbiologic exams verified the diagnosis. The AGS analysis revealed sensitivity, specificity and accuracy of value 1, while positive and negative predictive values were also 1. BS showed sensitivity of 1 and specificity of 0.33. In three cases, SPECT/CT scans corroborated the AGS interpretation. This diagnostic algorithm proved effective in the detection of septic loosening of hip prostheses. AGS can be avoided without risk of infection being overlooked.

  16. [Viscosity determination of synovial fluids from the canine hip and elbow joint as well as the human knee joint].

    PubMed

    Helms, Gabriele; Rittmann, Pia; Wefstaedt, Patrick; Windhagen, Henning; Pressel, Thomas; Behrens, Bernd-Arno; Nolte, Ingo

    2008-01-01

    The development of pathological changes in both human and canine hip joints is mainly caused by a lack of synovial fluid lubrication. This results in an increased joint abrasion. Even after implantation of joint prosthesis, inadequate lubrication can lead to abrasion in the tribological pair. This can finally result in aseptic loosening of the prosthesis. In spite of the enormous number of studies that have been performed on human, only little knowledge about the tribological properties of the joints in dogs is available in the literature. For this reason the viscosities of synovial fluid, derived from physiological and pathologically changed canine elbow joints were measured. The viscosities were determined by the use of a cone-plate viscometer at different temperatures and shear rates. The obtained values were compared with the viscosity values of pathologically changed synovial fluids from human knee joints as well as with pathological samples from the canine hip joint. The results show that the viscosity values vary within a series of measurements and are inversely proportional to the temperature of the sample and the shear rate. The differences between the average viscosities of canine and human synovial fluids taken from pathologically changed joints are below 4% (22.5 s(-1) at theta1 = 25 degrees C). The findings of this study are being implemented in a FE-Model for the computation of actual forces in the hip joint during different movements. This would represent a contribution to an improved prosthetic treatment of canine and human hips.

  17. [Gluteal compartment syndrome after total hip replacement. A presentation of two cases].

    PubMed

    Villalba, J; Solernou, X

    2013-01-01

    Many postoperative complications have been described after a total hip arthroplasty, with early and acute, as well as late, complications being reported. Two cases of compartment syndrome of the buttock are described following a hybrid total hip arthroplasty (cemented stem and press-fit and screwed acetabulum) performed on 2 patients of 60 and 68 years old, both diagnosed and treated 24-48 hours after the surgery. Both cases had a primary prosthesis with no previous significant pathological findings. This condition is still rare, and few cases have been described at the medical literature. Copyright © 2012 SECOT. Published by Elsevier Espana. All rights reserved.

  18. Outcomes of dual-mobility acetabular cup for instability in primary and revision total hip arthroplasty.

    PubMed

    Mohammed, Riazuddin; Hayward, Keith; Mulay, Sanjay; Bindi, Frank; Wallace, Murray

    2015-03-01

    The concept of a dual-mobility hip socket involves the standard femoral head component encased in a larger polyethylene liner, which in turn articulates inside a metal shell implanted in the native acetabulum. The aim of this study was to assess outcomes from using a Serf Novae(®) Dual Mobility Acetabular cup (Orthodynamics Ltd, Gloucestershire, UK) to address the problem of instability in primary and revision total hip arthroplasty (THA). A retrospective review was carried out of all hip arthroplasties performed in a District General Hospital utilising the dual-mobility socket from January 2007 to December 2012. Clinical and radiological outcomes were analysed for 44 hips in 41 patients, comprising 20 primary and 24 revision THA. The average age of the study group was 70.8 years (range 56-84 years) for primary and 76.4 years (range 56-89 years) for revision arthroplasty. Among the primary THA, always performed for hip osteoarthritis or in presence of osteoarthritic changes, the reasons to choose a dual mobility cup were central nervous system problems such as Parkinson's disease, stroke, dementia (10), hip fracture (5), failed hip fracture fixation (2), severe fixed hip deformity (2) and diffuse peripheral neuropathy (1). The indications for revisions were recurrent dislocation (17), aseptic loosening with abductor deficiency (4), failed hemiarthroplasty with abductor deficiency (2) and neglected dislocation (1). At a mean follow-up of 22 months (range 6-63 months), none of the hips had any dislocation, instability or infection and no further surgical intervention was required. Radiological assessment showed that one uncemented socket in a revision arthroplasty performed for recurrent dislocation had changed position, but was stable in the new position. The patient did not have complications from this and did not need any surgical intervention. Even though postoperative hip stability depends on several factors other than design-related ones, our study shows promising early results for reducing the risk of instability in this challenging group of patients undergoing primary and revision hip arthroplasty. IV.

  19. The boiled-egg technique: a new method for obtaining femoral head autograft used in acetabular defect reconstruction.

    PubMed

    Bucknall, Vittoria; Mehdi, Ali

    2013-09-01

    Primary total hip arthroplasty can be complicated by acetabular bony defects, threatening the biomechanical integrity of the prosthesis. Traditionally, when autologous bone is used to pack these defects, it is obtained from thin slices of femoral head in addition to acetabular reamings. We report a novel technique for the acquisition of autologous femoral head bone graft used in the reconstruction of acetabular defects during primary total hip arthroplasty. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. Metallic wear in failed titanium-alloy total hip replacements. A histological and quantitative analysis.

    PubMed

    Agins, H J; Alcock, N W; Bansal, M; Salvati, E A; Wilson, P D; Pellicci, P M; Bullough, P G

    1988-03-01

    We conducted extensive histological examination of the tissues that were adjacent to the prosthesis in nine hips that had a failed total arthroplasty. The prostheses were composed of titanium alloy (Ti-6Al-4V) and ultra-high molecular weight polyethylene. The average time that the prosthesis had been in place in the tissue was 33.5 months (range, eleven to fifty-seven months). Seven arthroplasties were revised because of aseptic loosening and two, for infection. In eight hips cement had been used and in one (that had a porous-coated implant for fifty-two months) no cement had been utilized. Intense histiocytic and plasma-cell reaction was noted in the pseudocapsular tissue. There was copious metallic staining of the lining cells. Polyethylene debris and particles of cement with concomitant giant-cell reaction were present in five hips. Atomic absorption spectrophotometry revealed values for titanium of fifty-sic to 3700 micrograms per gram of dry tissue (average, 1047 micrograms per gram; normal, zero microgram per gram), for aluminum of 2.1 to 396 micrograms per gram (average, 115 micrograms per gram; normal, zero micrograms per gram), and for vanadium of 2.9 to 220 micrograms per gram (average, sixty-seven micrograms per gram; normal, 1.2 micrograms per gram). The highest values were found in the hip in which surgical revision was performed at fifty-seven months. The concentrations of the three elements in the soft tissues were similar to those in the metal of the prostheses. The factors to which failure was attributed were: vertical orientation of the acetabular component (five hips), poor cementing technique on the femoral side (three hips), infection (two hips), and separation of a sintered pad made of pure titanium (one hip). A femoral component that is made of titanium alloy can undergo severe wear of the surface and on the stem, where it is loose, with liberation of potentially toxic local concentrations of metal debris into the surrounding tissues. It may contribute to infection and loosening.

  1. Comparison of different hip prosthesis shapes considering micro-level bone remodeling and stress-shielding criteria using three-dimensional design space topology optimization.

    PubMed

    Boyle, Christopher; Kim, Il Yong

    2011-06-03

    Since the late 1980s, computational analysis of total hip arthroplasty (THA) prosthesis components has been completed using macro-level bone remodeling algorithms. The utilization of macro-sized elements requires apparent bone densities to predict cancellous bone strength, thereby, preventing visualization and analysis of realistic trabecular architecture. In this study, we utilized a recently developed structural optimization algorithm, design space optimization (DSO), to perform a micro-level three-dimensional finite element bone remodeling simulation on the human proximal femur pre- and post-THA. The computational simulation facilitated direct performance comparison between two commercially available prosthetic implant stems from Zimmer Inc.: the Alloclassic and the Mayo conservative. The novel micro-level approach allowed the unique ability to visualize the trabecular bone adaption post-operation and to quantify the changes in bone mineral content by region. Stress-shielding and strain energy distribution were also quantified for the immediate post-operation and the stably fixated, post-remodeling conditions. Stress-shielding was highest in the proximal region and remained unchanged post-remodeling; conversely, the mid and distal portions show large increases in stress, suggesting a distal shift in the loadpath. The Mayo design conserves bone mass, while simultaneously reducing the incidence of stress-shielding compared to the Alloclassic, revealing a key benefit of the distinctive geometry. Several important factors for stable fixation, determined in clinical evaluations from the literature, were evident in both designs: high levels of proximal bone loss and distal bone densification. The results suggest this novel computational framework can be utilized for comparative hip prosthesis shape, uniquely considering the post-operation bone remodeling as a design criterion. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Estimation of wear in total hip replacement using a ten station hip simulator.

    PubMed

    Brummitt, K; Hardaker, C S

    1996-01-01

    The results of hip simulator tests on a total of 16 total hip joints, all of them 22.25 mm Charnley designs, are presented. Wear at up to 6.75 million cycles was assessed by using a coordinate measuring machine. The results gave good agreement with clinical estimates of wear rate on the same design of joint replacement from a number of sources. Good agreement was also obtained when comparison was made with the published results from more sophisticated simulators. The major source of variation in the results was found to occur in the first million cycles where creep predominates. The results of this study support the use of this type of simplified simulator for estimating wear in a total hip prosthesis. The capability to test a significant number of joints simultaneously may make this mechanism preferable to more complex machines in many cases.

  3. The History of Biomechanics in Total Hip Arthroplasty.

    PubMed

    Houcke, Jan Van; Khanduja, Vikas; Pattyn, Christophe; Audenaert, Emmanuel

    2017-01-01

    Biomechanics of the hip joint describes how the complex combination of osseous, ligamentous, and muscular structures transfers the weight of the body from the axial skeleton into the appendicular skeleton of the lower limbs. Throughout history, several biomechanical studies based on theoretical mathematics, in vitro , in vivo as well as in silico models have been successfully performed. The insights gained from these studies have improved our understanding of the development of mechanical hip pathologies such as osteoarthritis, hip fractures, and developmental dysplasia of the hip. The main treatment of end-stage degeneration of the hip is total hip arthroplasty (THA). The increasing number of patients undergoing this surgical procedure, as well as their demand for more than just pain relief and leading an active lifestyle, has challenged surgeons and implant manufacturers to deliver higher function as well as longevity with the prosthesis. The science of biomechanics has played and will continue to play a crucial and integral role in achieving these goals. The aim of this article, therefore, is to present to the readers the key concepts in biomechanics of the hip and their application to THA.

  4. Clinical and radiological mid-term results of the thrust plate prosthesis

    PubMed Central

    v.d. Daele, R.; Simon, U.; Goetze, C.

    2009-01-01

    The purpose of this study was to perform an objective clinical and radiological assessment of the thrust plate prosthesis (TPP). Fifty-three prostheses were evaluated clinically using the Harris hip score (HHS), visual analog scale (VAS), and radiographically before surgery, at the time of discharge, and postoperatively after on average of 8.09 (range 4.61–9.93) years. The average HHS significantly (p ≤ 0.05) improved from 48 (range 18–77) points to 95 (range 46–100) points. The VAS revealed significant (p ≤ 0.05) reduction of pain at rest and under load. Radiographic analysis showed a considerable potential for osteolysis under the thrust plate. Sixteen prostheses revealed signs of radiolucent zones. In general, there was a good clinical outcome with no major limitations in function. Radiographic changes under the thrust plate indicate an adaptation processes resulting from changed biomechanics. This study suggests that the TPP could be a good alternative in total hip replacement in younger patients. PMID:19184010

  5. [Dislocated fracture of the lesser trochanter with malrotation of the stem after robot assisted implantation of a cementless hip prosthesis: a casuistic report].

    PubMed

    Prymka, M; Hassenpflug, J

    2003-08-01

    This paper presents the case of a 63 year old female with a severe coxarthrosis. She got a robot assited implantation of a cementless hip prosthesis (Osteolock, Stryker-Howmedica, Mühlheim). As operation robot the CASPAR-System (Orto-Maquet, Rastatt) was used. Initially, the clinical progress of the patient was fine. She was nearly painfree within 14 days and showed an acceptable range of motion in the operated joint (flexion/ extension 90 degrees /05 degrees /00 degrees ). She was mobilized with crutches and 15 kg weight bearing at the operated leg. 3 weeks postoperative the patient complaint about increasing pain without trauma or intensification of the weight bearing. X-rays showed not only a dislocated fracture of the lesser trochanter, but also a sinking combined with a malrotation of the stem. A revision operation was necessary,where we implanted a cemented stem. Now clinical progress was completely satisfying.

  6. [Pelvic reconstructions after bone tumor resection].

    PubMed

    Anract, Philippe; Biau, David; Babinet, Antoine; Tomeno, Bernard

    2014-02-01

    The three more frequent primitive malignant bone tumour which concerned the iliac bone are chondrosarcoma, following Ewing sarcoma and osteosarcoma. Wide resection remains the most important part of the treatment associated with chemotherapy for osteosarcoma and the Ewing sarcoma. Iliac wing resections and obdurate ring don't required reconstruction. However, acetabular resections and iliac wing resection with disruption of the pelvic ring required reconstruction to provide acceptable functional result. Acetabular reconstruction remains high technical demanding challenge. After isolated acetabular resection or associated to obdurate ring, our usual method of reconstruction is homolateral proximal femoral autograft and total hip prosthesis but it is possible to also used : saddle prosthesis, Mac Minn prosthesis with auto or allograft, modular prosthesis or custom made prosthesis, massive allograft with or without prosthesis and femoro-ilac arthrodesis. After resection of the iliac wing plus acetabulum, reconstruction can be performed by femoro-obturatrice and femora-sacral arthrodesis, homolateral proximal femoral autograft and prosthesis, femoral medialisation, massive allograft and massive allograft. Carcinological results are lesser than resection for distal limb tumor, local recurrence rate range 17 to 45%. Functional results after Iliac wing and obdurate ring are good. However, acetabular reconstruction provide uncertain functional results. The lesser results arrive after hemipelvic or acetabular and iliac wing resection-reconstruction, especially when gluteus muscles were also resected. The most favourable results arrive after isolated acetabular or acetabular plus obturateur ring resection-reconstruction.

  7. Minimum ten-year results of primary bipolar hip arthroplasty for degenerative arthritis of the hip.

    PubMed

    Pellegrini, Vincent D; Heiges, Bradley A; Bixler, Brian; Lehman, Erik B; Davis, Charles M

    2006-08-01

    Bipolar hip arthroplasty has been advocated by some as an alternative to total hip arthroplasty for the treatment of degenerative arthritis of the hip. We sought to assess the results of this procedure at our institution after a minimum duration of follow-up of ten years. We retrospectively reviewed a consecutive series of 152 patients (173 hips) who underwent primary bipolar hemiarthroplasty for the treatment of symptomatic degenerative arthritis of the hip with a cementless femoral component between 1983 and 1987. Of the original cohort of 152 patients, ninety-two patients (104 hips) were available for clinical and radiographic review at a mean of 12.2 years postoperatively. At the time of the latest follow-up, self-administered Harris hip questionnaires were used to assess pain, mobility, activity level, and overall satisfaction with the procedure. Biplanar hip radiographs were made to evaluate bipolar shell migration, osteolysis, and femoral stem fixation. At the time of the latest follow-up, nineteen patients (nineteen hips) had undergone revision to total hip arthroplasty because of mechanical failure, and three patients (three hips) were awaiting revision because of symptomatic radiographic mechanical failure. Twelve acetabular revisions were performed or scheduled for the treatment of pelvic osteolysis or protrusio acetabuli secondary to component migration. Acetabular reconstruction required bone-grafting, an oversized shell, and/or a pelvic reconstruction ring. The overall rate of mechanical failure was 21.2% (twenty-two of 104 hips), with 91% (twenty) of the twenty-two failures involving the acetabular component. Reaming of the acetabulum at the time of the index arthroplasty was associated with a 6.4-fold greater risk of revision. The rate of implant survival, with revision because of mechanical failure as the end point, was 94.2% for femoral components and 80.8% for acetabular components at a mean of 12.2 years. Of the remaining sixty-nine patients (eighty-one hips) in whom the original prosthesis was retained, seventeen patients (24.6%) rated the pain as moderate to severe. Nearly 30% of patients with an intact prosthesis required analgesics on a regular basis. Radiographs were available for fifty-eight hips (including all of the hips with moderate to severe pain) after a minimum duration of follow-up of ten years; twenty-eight of these fifty-eight hips had radiographic evidence of acetabular component migration. This bipolar cup, when used for hemiarthroplasty in patients with symptomatic arthritis of the hip, was associated with unacceptably high rates of pain, migration, osteolysis, and the need for revision to total hip arthroplasty, especially when the acetabulum had been reamed. To the extent that these findings can be generalized to similar implant designs with conventional polyethylene, we do not recommend bipolar hemiarthroplasty as the primary operative treatment for degenerative arthritis of the hip.

  8. Centre of mass determination based on an optical weighing machine using fiber Bragg gratings

    NASA Astrophysics Data System (ADS)

    Oliveira, Rui; Roriz, Paulo; Marques, Manuel B.; Frazão, Orlando

    2015-09-01

    The purpose of the present work was to construct a weighing machine based on fiber Bragg gratings (FBGs) for the location of the 2D coordinates of the center of gravity (COG) of objects with complex geometry and density distribution. The apparatus consisted of a rigid equilateral triangular platform mounted on three supports at its vertices, two of them having cantilevers instrumented with FBGs. As an example, two femur bone models, one with and one without a hip stem prosthesis, are used to discuss the changing of the COM caused by the implementation of the prosthesis.

  9. Biomechanical study of pelvic discontinuity in failed total hip arthroplasty. Lessons learnt from the treatment of pelvic fractures.

    PubMed

    Ribes-Iborra, Julio; Atienza, Carlos; Sevil-De la Torre, Jorge; Gómez Pérez, Amelia

    2017-11-01

    Pelvic discontinuity is a rare but serious problem in orthopedic surgery. Acetabular reconstruction in case of severe bone loss after failed total hip arthroplasty is technically difficult, especially in segmental loss type III (anterior or posterior) or pelvic discontinuity (type IV). Acetabular reinforcement devices are frequently used as load-sharing devices to allow allograft incorporation and in order to serve as support of acetabular implants. This study tries to show, by means of biomechanic work, the efficiency of reinforced plate in anterior column in a segmental pelvic loss, illustrated with a clinical case, which shows the socket stability of hip prosthesis. © 2017 Elsevier Ltd. All rights reserved.

  10. Birmingham Mid-Head Resection hip arthroplasty in a young man with gigantism.

    PubMed

    Murphy, Michael T; Shillington, Mark P; Mogridge, Damon R; Journeaux, Simon F

    2012-02-01

    The Birmingham Mid-Head Resection (Smith & Nephew Ltd, Warwick, United Kingdom) arthroplasty is a new bone-conserving procedure that, like hip resurfacing, is used in younger, active patients. We present the case of a young man with Sotos syndrome (cerebral gigantism) with associated extraordinary stature (height, 2.16 m; weight, 157 kg) who underwent Birmingham Mid-Head Resection arthroplasty. The large stature of this patient required a custom manufactured prosthesis (a femoral head 68 mm in diameter with an acetabular cup 76 mm in diameter). We believe this to be the largest metal-on-metal resurfacing articulation and hip arthroplasty reported to date. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Economic Analysis of 4221 Revisions Due to Periprosthetic Joint Infection in Poland.

    PubMed

    Babiak, Ireneusz; Pędzisz, Piotr; Janowicz, Jakub; Kulig, Mateusz; Małdyk, Paweł

    2017-01-26

    Periprosthetic joint infection (PJI) is one of the most severe complications of total hip (THA) and total knee (TKA) arthroplasty. The aim of the study is to determine the number and type of hip and knee prosthesis revisions in Poland performed due to infection and reimbursement of the cost of septic revisions and to compare the costs of septic and aseptic revisions in Poland and other countries. The data published for the period 2009-2013 by the National Health Fund (NHF) were analysed and the average cost of septic and aseptic revisions was calculated. In the years 2009-2013, a total of 260,030 hip and knee arthroplasties including 23,027 revisions (incl. 4,221 septic) were performed in Poland. In 2013, septic revisions accounted for 1.38% of all hip replacement procedures, 2.56% of all knee replacement procedures and 14.67% of all hip revisions and 30.23% of all knee revisions. In 2013, the difference between the average cost incurred by the hospital and the NHF refund for septic revision due to PJI was at least €238 and the cost-refund gap for the entire year was €219198. 1. The system of reporting periprostheticjoint infections currently in use in Poland does not adequately reflect the current classification of PJI and reimbursement for septic revision of joint prosthesis does not match the actual costs. 2. The Polish DRG system does not distinguish between early and late PJI and fails to acknowledge basic guidelines for infection treatment currently followed in Poland and worldwide. 3. According to the DRG system, patients requiring different treatment are placed in one category. 4. Until the year 2013, the less expensive treatment of early infections had been reimbursed on the same basis as the more costly two-stage revision procedures.

  12. Pre-operative Predictive Factors of Post-operative Pain in Patients With Hip or Knee Arthroplasty: A Systematic Review.

    PubMed

    Hernández, Clara; Díaz-Heredia, Jorge; Berraquero, María Luisa; Crespo, Pablo; Loza, Estíbaliz; Ruiz Ibán, Miguel Ángel

    2015-01-01

    To analyze pre-surgical predictive factors of post-surgical pain in patients undergoing hip or knee arthoplasty. A systematic literature review was performed. We defined a sensitive strategy on Medline, Embase and Cochrane Library up to May 2013. The inclusion criteria were: patients undertaking knee and/or hip arthroplasty, adults with moderate or severe pain (≥4 on a Visual Analog Scale) in whom predictive factors of post-surgical pain were evaluated before surgery. Systematic reviews, meta-analyses, controlled trials and observational studies were selected. We excluded animals and basic science articles, reviews of prosthesis, prosthesis due to fractures, patients with rheumatic diseases or studies with mixed population in which disaggregated data was not possible to obtain. A total 37 articles of moderate quality were selected. The articles included representative patients undergoing a knee or hip arthroplasty in our country; most of them were aged 60 years or above, with osteoarthritis, and with a high rate of obesity and comorbidities. We found great variability regarding the type of studies and predictive factors. There was a strong association between post-surgical pain and the following pre-surgical factors: female gender, low socio-economic status, higher pain, comorbidities, low back pain, poor functional status, and psychological factors (depression, anxiety or catastrophic pain). There are pre-surgical factors that might influence post-surgical pain in patients undergoing a knee or hip arthroplasty. Therefore, they should be taken into account when considering an arthroplasty. Copyright © 2014 Elsevier España, S.L.U. y Sociedad Española de Reumatología y Colegio Mexicano de Reumatología. All rights reserved.

  13. Preliminary application of computer-assisted patient-specific acetabular navigational template for total hip arthroplasty in adult single development dysplasia of the hip.

    PubMed

    Zhang, Yuan Z; Chen, Bin; Lu, Sheng; Yang, Yong; Zhao, Jian M; Liu, Rui; Li, Yan B; Pei, Guo X

    2011-12-01

    The considerable variation in anatomical abnormalities of hip joints associated with different types of developmental dysplasia of hip (DDH) makes reconstruction in total hip arthroplasty (THA) difficult. It is desirable to create patient-specific designs for THA procedures. In the cases of adult single DDH, an accuracy-improved method has been developed for acetabular cup prosthesis implantation of hip arthroplasty. From October 2007 to November 2008, 22 patients with single DDH (according to the Crowe standard, all dysplasia hips were classified as type I) were scanned with spiral CT pre-operatively. These patients scheduled for THA were randomly assigned to undergo either conventional THA (control group, n = 11) or navigation template implantation (NT group, n = 11). In the NT group, three-dimensional (3D) CT pelvis image data were transferred to a computer workstation and 3D models of the hip were reconstructed using the Mimics software. The 3D models were then processed by the Imageware software. In brief, a template that best fitted the location and shape of the acetabular cup was 'reversely' built from the 3D model, the rotation centre of the pathological hip determined by mirroring that of the healthy site, and a guiding hole in the template was then designed. The navigational templates were manufactured using a rapid prototyping machine. These navigation templates guide acetabular component placement. Based on the predetermined abduction angle 45° and anteversion angle 18°, after 1 year follow-up, the NT group showed significantly smaller differences (1.6° ± 0.4°, 1.9° ± 1.1°) from the predetermined angles than those in the control group (5.8° ± 2.9°, 3.9° ± 2.5°) (P < 0.05). The template designs facilitated accurate placement of acetabular components in dysplasia of acetabulum. The hip's center of rotation in DDH could be established using computer-aided design, which provides a useful method for the accurate location of prosthesis with a low cost-performance ratio without excessive technical workload on the surgical team. Copyright © 2011 John Wiley & Sons, Ltd.

  14. [Total hip arthroplasty in post-dysplastic hip arthritis. Can type and position of the acetabular component influence longevity of the prosthesis?].

    PubMed

    Fousek, J; Indráková, P

    2007-02-01

    The aim of the study was a retrospective evaluation of our patients with post-dysplastic hips treated by cemented or non-cemented total hip arthroplasty (THA) in order to ascertain which type and position of the acetabular component was most effective. In the years 1999-2002, 111 THA procedures were performed in 93 patients, 76 women and 17 men, with post-dysplastic hip arthritis. The average age of the patients at the time of implantation was 52.6 years. On the basis of pre-operative radiographic findings, the patients' conditions were evaluated using the Hartofilakidis classification into three disease categories: dysplasia, low dislocation and high dislocation, and the patients were placed in two groups. Group 1 included 78 patients, and group 2 comprised 26 patients. None of our patients was classified as having high dislocation. Thirty-nine of these patients had previously undergone surgery for dysplastic hips. A total of 104 THAs were evaluated, because radiographic data was incomplete in seven cases. In addition to X-ray findings, the prosthesis type (cemented, hybrid, non-cemented), post-operative complications and signs of loosening were included in the evaluation. Clinical outcomes were assessed by the Harris score. The follow-up terminating on 31st December 2005 was 67 months on the average. In group 1 patients, the average Harris score increased from 38.6 to 80.3 points and in group 2 patients from 35.5 to 84.9 points, mostly with excellent and good results. In 72.1 % of the hips, a press-fit acetabular component was implanted. In 55.8 % of the cases, the acetabular component was implanted off the anatomical center of rotation, into the high hip center, with the range from 9 to 20 mm and an average of 15 mm. The average limb lengthening was 2.5 cm, ranging from 1.0 to 3.5 cm. Our results show that it is more effective to use non-cemented THA for post-dysplastic hips. The implantation of a noncemented acetabular component into the high center provides better covering of the cup with solid bone, without the necessity of cotyloplasty or structural graft use. Also, it does not markedly affect hip function or patients' subjective feelings.

  15. Biomedical technology transfer. Applications of NASA science and technology

    NASA Technical Reports Server (NTRS)

    Harrison, D. C.

    1980-01-01

    Ongoing projects described address: (1) intracranial pressure monitoring; (2) versatile portable speech prosthesis; (3) cardiovascular magnetic measurements; (4) improved EMG biotelemetry for pediatrics; (5) ultrasonic kidney stone disintegration; (6) pediatric roentgen densitometry; (7) X-ray spatial frequency multiplexing; (8) mechanical impedance determination of bone strength; (9) visual-to-tactile mobility aid for the blind; (10) Purkinje image eyetracker and stabilized photocoalqulator; (11) neurological applications of NASA-SRI eyetracker; (12) ICU synthesized speech alarm; (13) NANOPHOR: microelectrophoresis instrument; (14) WRISTCOM: tactile communication system for the deaf-blind; (15) medical applications of NASA liquid-circulating garments; and (16) hip prosthesis with biotelemetry. Potential transfer projects include a person-portable versatile speech prosthesis, a critical care transport sytem, a clinical information system for cardiology, a programmable biofeedback orthosis for scoliosis a pediatric long-bone reconstruction, and spinal immobilization apparatus.

  16. A femoral component inserted without cement in total hip arthroplasty. A study of the Tri-Lock component with an average ten-year duration of follow-up.

    PubMed

    Burt, C F; Garvin, K L; Otterberg, E T; Jardon, O M

    1998-07-01

    Seventy-four total hip arthroplasties in sixty-six patients were performed, between 1983 and 1986, with use of a Tri-Lock femoral component inserted without cement. This tapered cobalt-chromium component has a fixed head and a circumferential proximal porous coating. Follow-up was conducted with use of a questionnaire, physical examination, and radiographic analysis. At the time of the latest follow-up, fifteen patients (eighteen hips) had died, three patients (four hips) had been lost to follow-up, and one patient (one hip) had refused to participate in the follow-up study; however, the status of fifteen hips at the time of death could be verified. Thus, clinical follow-up data were available for sixty-six of the original seventy-four hips. The average age at the time of the operation was sixty-two years (range, seventeen to eighty-four years), and the average interval between the operation and the latest follow-up evaluation was 10.0 years (range, 8.3 to 11.6 years). The Harris hip score was determined for forty-three hips (forty-one patients) in which the prosthesis was in situ at the time of the latest follow-up. The score was good for thirteen hips and excellent for twenty-eight, so the rate of clinical success was 95 per cent. Two patients had a fair result. One of them had persistent pain and the other had limited motion, but neither had radiographic evidence of loosening of the femoral or acetabular component. All forty-one patients were satisfied with the result. The probability (with standard error) of survival of the femoral component at ten years, with revision as the end point, was 0.95 +/- 0.03. The rate of revision of the femoral component because of aseptic loosening was one (2 per cent) of sixty-six. The overall rate of aseptic loosening of the femoral component in the hips that were followed radiographically was two (4 per cent) of forty-seven. Only one (2 per cent) of the forty-seven acetabular cups had evidence of aseptic loosening. There was no radiographic evidence of distal osteolysis around the prostheses that were well fixed. Proximal osteolysis was present in five (11 per cent) of forty-seven hips, but none of the lesions compromised the stability of the prosthesis or the bone and there were no associated fractures. At an average of ten years postoperatively, the Tri-Lock femoral component functioned well overall and patient satisfaction was high.

  17. The biomechanical response of persons with transfemoral amputation to variations in prosthetic knee alignment during level walking.

    PubMed

    Koehler-McNicholas, Sara R; Lipschutz, Robert D; Gard, Steven A

    2016-01-01

    Prosthetic alignment is an important factor in the overall fit and performance of a lower-limb prosthesis. However, the association between prosthetic alignment and control strategies used by persons with transfemoral amputation to coordinate the movement of a passive prosthetic knee is poorly understood. This study investigated the biomechanical response of persons with transfemoral amputation to systematic perturbations in knee joint alignment during a level walking task. Quantitative gait data were collected for three alignment conditions: bench alignment, 2 cm anterior knee translation (ANT), and 2 cm posterior knee translation (POST). In response to a destabilizing alignment perturbation (i.e., the ANT condition), participants significantly increased their early-stance hip extension moment, confirming that persons with transfemoral amputation rely on a hip extensor strategy to maintain knee joint stability. However, participants also decreased the rate at which they loaded their prosthesis, decreased their affected-side step length, increased their trunk flexion, and maintained their prosthesis in a more vertical posture at the time of opposite toe off. Collectively, these results suggest that persons with transfemoral amputation rely on a combination of strategies to coordinate stance-phase knee flexion. Further, comparatively few significant changes were observed in response to the POST condition, suggesting that a bias toward posterior alignment may have fewer implications in terms of stance-phase, knee joint control.

  18. Failure of a novel ceramic-on-ceramic hip resurfacing prosthesis.

    PubMed

    Matharu, Gulraj S; Daniel, Joseph; Ziaee, Hena; McMinn, Derek J W

    2015-03-01

    We report the early failure of five ceramic-on-ceramic hip resurfacings (CoCHRs). The ceramic used for the acetabular liner was a novel ceramic-composite (two thirds polyurethane and one third alumina ceramic). All cases were revised for increasing metal ion levels (blood cobalt 3.93-208.0 μg/l and chromium 1.57-17.5 μg/l) due to ceramic liner fracture and/or accelerated wear of the ceramic femoral head coating. Patients underwent bearing exchange and revision using primary hip arthroplasty implants at a mean of 3.0 years following CoCHR. Intraoperatively all patients had metallosis. At 1 to 2 years of follow-up blood metal ions normalized with no complications. We do not recommend this particular type of ceramic-on-ceramic bearing for hip resurfacing. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. A prospective dual-energy X-ray absorptiometry study of bone remodeling after implantation of the Nanos short-stemmed prosthesis.

    PubMed

    Zeh, Alexander; Pankow, Franziska; Röllinhoff, Marc; Delank, Stefan; Wohlrab, David

    2013-04-01

    The aim of this study was to analyze the bone remodeling around the Nanos stem (Smith & Nephew, Marl, Germany) after primary total hip arthroplasty for coxarthrosis. In 25 patients (15 male, 10 female, mean age 59.9 years) with the diagnosis of coxarthrosis, a DEXA scan was performed immediately after surgery, 97 days (SD 6.1 days) and 368 days (SD 6.2 days) after implantation of a Nanos prosthesis. Plain radiographs were analyzed digitally for radiolucent lines, varus-valgus femoral stem alignment, measurement of stem migration and changes in varus-valgus femoral stem alignment. The position of the center of rotation (COR) and the offset were assessed pre- and postoperatively. Harris Hip Score was used to evaluate the clinical outcome. The DEXA scan showed a significant and relevant increase in BMD (Bone Mineral Density) in Gruen-Zone 6 (12%) and a decrease in Zone 1 (15%), 2 (5%) and 7 (12%), which was interpreted as reflecting a distal load transfer in the metaphysis of the femur. There was no clinically relevant migration or tilting of the Nanos stem. Radiolucent lines were noted in 12 cases, mainly at the polished tip area of the prosthesis; this was not regarded as a sign of impaired osseointegration. There was no significant difference between the position of the COR and the pre- and postoperative offset. The absence of stem migration, angulation, or relevant radiolucent lines is seen as evidence for an unimpaired osseointegration of the Nanos stem approximately 12 months after implantation. It is concluded that the Nanos prosthesis can reduce loss of BMD of the proximal femur composed with conventional stems or other short-stemmed implants.

  20. Agreement between pre-operative and intra-operative bacteriological samples in 85 chronic peri-prosthetic infections.

    PubMed

    Matter-Parrat, V; Ronde-Oustau, C; Boéri, C; Gaudias, J; Jenny, J-Y

    2017-04-01

    Whether pre-operative microbiological sampling contributes to the management of chronic peri-prosthetic infection remains controversial. We assessed agreement between the results of pre-operative and intra-operative samples in patients undergoing single-stage prosthesis exchange to treat chronic peri-prosthetic infection. Agreement between pre-operative and intra-operative samples exceeds 75% in patients undergoing single-stage exchange of a hip or knee prosthesis to treat chronic peri-prosthetic infection. This single-centre retrospective study included 85 single-stage prosthesis exchange procedures in 82 patients with chronic peri-prosthetic infection at the hip or knee. Agreement between pre-operative and intra-operative sample results was evaluated. Changes to the initial antibiotic regimen made based on the intra-operative sample results were recorded. Of 149 pre-operative samples, 109 yielded positive cultures, in 75/85 cases. Of 452 intra-operative samples, 354 yielded positive cultures, in 85/85 cases. Agreement was complete in 54 (63%) cases and partial in 9 (11%) cases; there was no agreement in the remaining 22 (26%) cases. The complete agreement rate was significantly lower than 75% (P=0.01). The initial antibiotic regimen was inadequate in a single case. Pre-operative sampling may contribute to the diagnosis of peri-prosthetic infection but is neither necessary nor sufficient to confirm the diagnosis and identify the causative agent. The spectrum of the initial antibiotic regimen cannot be safely narrowed based on the pre-operative sample results. We suggest the routine prescription of a probabilistic broad-spectrum antibiotic regimen immediately after the prosthesis exchange, even when a pathogen was identified before surgery. IV, retrospective study. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  1. The effect of metal artefact reduction on CT-based attenuation correction for PET imaging in the vicinity of metallic hip implants: a phantom study.

    PubMed

    Harnish, Roy; Prevrhal, Sven; Alavi, Abass; Zaidi, Habib; Lang, Thomas F

    2014-07-01

    To determine if metal artefact reduction (MAR) combined with a priori knowledge of prosthesis material composition can be applied to obtain CT-based attenuation maps with sufficient accuracy for quantitative assessment of (18)F-fluorodeoxyglucose uptake in lesions near metallic prostheses. A custom hip prosthesis phantom with a lesion-sized cavity filled with 0.2 ml (18)F-FDG solution having an activity of 3.367 MBq adjacent to a prosthesis bore was imaged twice with a chrome-cobalt steel hip prosthesis and a plastic replica, respectively. Scanning was performed on a clinical hybrid PET/CT system equipped with an additional external (137)Cs transmission source. PET emission images were reconstructed from both phantom configurations with CT-based attenuation correction (CTAC) and with CT-based attenuation correction using MAR (MARCTAC). To compare results with the attenuation-correction method extant prior to the advent of PET/CT, we also carried out attenuation correction with (137)Cs transmission-based attenuation correction (TXAC). CTAC and MARCTAC images were scaled to attenuation coefficients at 511 keV using a trilinear function that mapped the highest CT values to the prosthesis alloy attenuation coefficient. Accuracy and spatial distribution of the lesion activity was compared between the three reconstruction schemes. Compared to the reference activity of 3.37 MBq, the estimated activity quantified from the PET image corrected by TXAC was 3.41 MBq. The activity estimated from PET images corrected by MARCTAC was similar in accuracy at 3.32 MBq. CTAC corrected PET images resulted in nearly 40 % overestimation of lesion activity at 4.70 MBq. Comparison of PET images obtained with the plastic and metal prostheses in place showed that CTAC resulted in a marked distortion of the (18)F-FDG distribution within the lesion, whereas application of MARCTAC and TXAC resulted in lesion distributions similar to those observed with the plastic replica. MAR combined with a trilinear CT number mapping for PET attenuation correction resulted in estimates of lesion activity comparable in accuracy to that obtained with (137)Cs transmission-based attenuation correction, and far superior to estimates made without attenuation correction or with a standard CT attenuation map. The ability to use CT images for attenuation correction is a potentially important development because it obviates the need for a (137)Cs transmission source, which entails extra scan time, logistical complexity and expense.

  2. Dosimetric study of uniform scanning proton therapy planning for prostate cancer patients with a metal hip prosthesis, and comparison with volumetric‐modulated arc therapy

    PubMed Central

    Cheng, ChihYao; Zheng, Yuanshui; Hsi, Wen; Zeidan, Omar; Schreuder, Niek; Vargas, Carlos; Larson, Gary

    2014-01-01

    The main purposes of this study were to 1) investigate the dosimetric quality of uniform scanning proton therapy planning (USPT) for prostate cancer patients with a metal hip prosthesis, and 2) compare the dosimetric results of USPT with that of volumetric‐modulated arc therapy (VMAT). Proton plans for prostate cancer (four cases) were generated in XiO treatment planning system (TPS). The beam arrangement in each proton plan consisted of three fields (two oblique fields and one lateral or slightly angled field), and the proton beams passing through a metal hip prosthesis was avoided. Dose calculations in proton plans were performed using the pencil beam algorithm. From each proton plan, planning target volume (PTV) coverage value (i.e., relative volume of the PTV receiving the prescription dose of 79.2 CGE) was recorded. The VMAT prostate planning was done using two arcs in the Eclipse TPS utilizing 6 MV X‐rays, and beam entrance through metallic hip prosthesis was avoided. Dose computation in the VMAT plans was done using anisotropic analytical algorithm, and calculated VMAT plans were then normalized such that the PTV coverage in the VMAT plan was the same as in the proton plan of the corresponding case. The dose‐volume histograms of calculated treatment plans were used to evaluate the dosimetric quality of USPT and VMAT. In comparison to the proton plans, on average, the maximum and mean doses to the PTV were higher in the VMAT plans by 1.4% and 0.5%, respectively, whereas the minimum PTV dose was lower in the VMAT plans by 3.4%. The proton plans had lower (or better) average homogeneity index (HI) of 0.03 compared to the one for VMAT (HI = 0.04). The relative rectal volume exposed to radiation was lower in the proton plan, with an average absolute difference ranging from 0.1% to 32.6%. In contrast, using proton planning, the relative bladder volume exposed to radiation was higher at high‐dose region with an average absolute difference ranging from 0.4% to 0.8%, and lower at low‐ and medium‐dose regions with an average absolute difference ranging from 2.7% to 10.1%. The average mean dose to the rectum and bladder was lower in the proton plans by 45.1% and 22.0%, respectively, whereas the mean dose to femoral head was lower in VMAT plans by an average difference of 79.6%. In comparison to the VMAT, the proton planning produced lower equivalent uniform dose (EUD) for the rectum (43.7 CGE vs. 51.4 Gy) and higher EUD for the femoral head (16.7 CGE vs. 9.5 Gy), whereas both the VMAT and proton planning produced comparable EUDs for the prostate tumor (76.2 CGE vs. 76.8 Gy) and bladder (50.3 CGE vs. 51.1 Gy). The results presented in this study show that the combination of lateral and oblique fields in USPT planning could potentially provide dosimetric advantage over the VMAT for prostate cancer involving a metallic hip prosthesis. PACS number: 87.55.D‐, 87.55.ne, 87.55.dk PMID:24892333

  3. An integrated CAD/CAM/robotic milling method for custom cementless femoral prostheses.

    PubMed

    Wen-ming, Xi; Ai-min, Wang; Qi, Wu; Chang-hua, Liu; Jian-fei, Zhu; Fang-fang, Xia

    2015-09-01

    Aseptic loosening is the primary cause of cementless femoral prosthesis failure and is related to the primary stability of the cementless femoral prosthesis in the femoral cavity. The primary stability affects both the osseointegration and the long-term stability of cementless femoral prostheses. A custom cementless femoral prosthesis can improve the fit and fill of the prosthesis in the femoral cavity and decrease the micromotion of the proximal prosthesis such that the primary stability of the custom prosthesis can be improved, and osseointegration of the proximal prosthesis is achieved. These results will help to achieve long-term stability in total hip arthroplasty (THA). In this paper, we introduce an integrated CAD/CAM/robotic method of milling custom cementless femoral prostheses. The 3D reconstruction model uses femoral CT images and 3D design software to design a CAD model of the custom prosthesis. After the transformation matrices between two units of the robotic system are calibrated, consistency between the CAM software and the robotic system can be achieved, and errors in the robotic milling can be limited. According to the CAD model of the custom prosthesis, the positions of the robotic tool points are produced by the CAM software of the CNC machine. The normal vector of the three adjacent robotic tool point positions determines the pose of the robotic tool point. In conclusion, the fit rate of custom pig femur stems in the femoral cavities was 90.84%. After custom femoral prostheses were inserted into the femoral cavities, the maximum gaps between the prostheses and the cavities measured less than 1 mm at the diaphysis and 1.3 mm at the metaphysis. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

  4. Bipolar femoral head arthroplasty in osteoarthritis. A prospective study with a minimum 5-year follow-up period.

    PubMed

    Pandit, R

    1996-08-01

    Primary bipolar femoral head arthroplasties performed on 100 osteoarthritic hips were studied to a minimum of 5 years after surgery. All arthroplasties were performed on physically active patients. At a mean follow-up period of 5.5 years, The Hospital for Special Surgery hip scores were good to excellent in 96 hips. Transient startup soreness constituted the most frequent complaint, occurring in 34 hips. Three hips had more persistent pain localized to the acetabulum, necessitating revision to fixed sockets, which alleviated the symptoms. Four additional hips, in heavy, active men, developed polyethylene fatigue fracture and component disassembly. Acetabular migration of more than 5 mm developed in one hip. Motion, as determined radiologically, occurred primarily at the inner bearing. There were no dislocations or infections in the series. The Bateman bipolar prosthesis provides generally good results in osteoarthritic hips. The shorter operating time and the case of revision are special advantages of bipolar devices. Start-up soreness and stiffness is a shortcoming in approximately one third of cases. Component disassembly in heavy, active men is a problem and the bipolar arthroplasty should be avoided in these patients. Start-up soreness was a significant problem in particular.

  5. [Detection of metal ions in hair after metal-metal hip arthroplasty].

    PubMed

    Hernandez-Vaquero, D; Rodríguez de la Flor, M; Fernandez-Carreira, J M; Sariego-Muñiz, C

    2014-01-01

    There is an increase in the levels of metals in the serum and urine after the implantation of some models of metal-metal hip prosthesis. It has recently been demonstrated that there is an association between these levels and the levels found in hair. The aim of this study is to determine the presence of metals in hair, and to find out whether these change over time or with the removal of the implant. The levels of chromium, cobalt and molybdenum were determined in the hair of 45 patients at 3, 4, 5, and 6 years after a hip surface replacement. The mean age was 57.5 years, and two were female. Further surgery was required to remove the replacement and implant a new model with metal-polyethylene friction in 11 patients, 5 of them due to metallosis and a periarticular cyst. The mean levels of metals in hair were chromium 163.27 ppm, cobalt 61.98 ppm, and molybdenum 31.36 ppm, much higher than the levels found in the general population. A decrease in the levels of chromium (43.8%), molybdenum (51.1%), and cobalt (91.1%) was observed at one year in the patients who had further surgery to remove the prosthesis. High concentrations of metals in the hair are observed in hip replacements with metal-metal friction, which decrease when that implant is removed. The determination of metal ions in hair could be a good marker of the metal poisoning that occurs in these arthroplasty models. Copyright © 2014 SECOT. Published by Elsevier Espana. All rights reserved.

  6. [Total knee and hip prosthesis: variables associated with costs].

    PubMed

    Herrera-Espiñeira, Carmen; Escobar, Antonio; Navarro-Espigares, José Luis; Castillo, Juan de Dios Lunadel; García-Pérez, Lidia; Godoy-Montijano, Amparo

    2013-01-01

    The elevated prevalence of osteoarthritis in Western countries, the high costs of hip and knee arthroplasty, and the wide variations in the clinical practice have generated considerable interest in comparing the associated costs before and after surgery. To determine the influence of a number of variables on the costs of total knee and hip arthroplasty surgery during the hospital stay and during the one-year post-discharge. A prospective multi-center study was performed in 15 hospitals from three Spanish regions. Relationships between the independent variables and the costs of hospital stay and postdischarge follow-up were analyzed by using multilevel models in which the "hospital" variable was used to group cases. Independent variables were: age, sex, body mass index, preoperative quality of life (SF-12, EQ-5 and Womac questionnaires), surgery (hip/knee), Charlson Index, general and local complications, number of beds and economic-institutional dependency of the hospital, the autonomous region to which it belongs, and the presence of a caregiver. The cost of hospital stay, excluding the cost of the prosthesis, was 4,734 Euros, and the post-discharge cost was 554 Euros. With regard to hospital stay costs, the variance among hospitals explained 44-46% of the total variance among the patients. With regard to the post-discharge costs, the variability among hospitals explained 7-9% of the variance among the patients. There is considerable potential for reducing the hospital stay costs of these patients, given that more than 44% of the observed variability was not determined by the clinical conditions of the patients but rather by the behavior of the hospitals.

  7. [Femorotomy and cleaning for infected hip prostheses: report of 30 cases].

    PubMed

    Lortat-Jacob, A; Nourrissat, G; Cadu, C

    2001-10-01

    We report infected hip prostheses treated by an original technique: frontal femorotomy after trochanterotomy. This extensive technique enables perfect cleaning of the femur and truly effective freshening of the endomedullar canal. We report 30 cases operated since 1991 use of femorotomy has been systematic from 1995. We were able to reimplant 25 of these 30 hips. Our results after infection were rather good with 4 recurrent infections in difficult cases (multi-operated patients and multiresistant germs in half of the cases). Fusion of femorotomy was obtained in all cases. The mechanical outcome was not improved by femorotomy. The main problem was trochanter nonunion with 5 cases, all of them having had a trochanteromy during the first procedure. We use femorotomy as our routine technique for femoral cleaning in case of hip prosthesis infection. In less complicated cases, we do not remove the trochanter from the femoral valve, limiting trochanteric complications, the main problem with this technique.

  8. Evaluation of Spine Health and Spine Mechanics in Servicemembers with Traumatic Lower Extremity Amputation or Injury

    DTIC Science & Technology

    2015-10-01

    of proximal compensations (e.g., hip-hiking) to assist with toe clearance (Michaud et al., 2000), or simply because these individuals feel more...related unilateral lower extremity amputation: a long-term survey in a prosthesis center in Iran. Journal of orthopaedic trauma 23(7), 525-530

  9. A Morlet wavelet signal analysis with a Daubechies filter for the wear assessment of hip prostheses coated with diamond-like carbon by triboadhesion.

    PubMed

    Rodríguez-Lelis, Jose Maria; Mata, Dagoberto Tolosa; Vargas-Treviño, Marciano; Navarro-Torres, Jose; Piña-Piña, Gilberto; Abundez-Pliego, Arturo

    2010-08-01

    In the present work, based on high frequency wavelet analysis of dynamic signals of mechanical systems, a multiple-resolution wavelet analysis is carried out, to the signal obtained from an accelerometer mounted on the structure of a hip prosthesis wearing test device. The prostheses employed had a femoral head made of aluminum oxide and the acetabular cup of ultra-high-molecular-weight polyethylene. The first two aluminum oxide femoral heads were coated with diamond-like carbon and a third one was tested without coating and used as a reference. The coating was carried out by triboadhesion. Tests results showed that maximum vibration amplitude reached after 32 hr for the coated prostheses was 0.2 g. The noncoated prosthesis amplitude presented was 0.75 g in the same time interval. These values were attributed to wear damage on the surface of the prostheses, indicating that thin film DLC coating caused an increase of stiffness on the surface and therefore an increase in wear resistance approximately of 314%.

  10. Olminska and colleagues' study, "Conversion of the helical tomotherapy plans to the step-and-shoot IMRT plans for patients with hip prosthesis during radiotherapy for prostate cancer" was interesting to read.

    PubMed

    Cihan, Yasemin Benderli

    2016-11-01

    Olmińska and colleagues' study, Olmińska et al. (2016) was interesting to read [1]. While prasining the authors for their great work, I want to emphasize e few points. In the recent years, with the development of new device technology, Intensity Modulated Radiotherapy (IMRT) and complex treatment modalities such as stereotactic radiosurgery and helical tomotherapy were started to be implemented. Thus, due to increased local control of tumor growth and reduction of dose received by surrounding critical organs, serious complications were avoided. In this new treatment modality, while calculating appropriate dose, all the parameters such as patient anatomy and characteristics of radiation should be taken into account. Besides, during conformal radiotherapy, if hip prosthesis is located around or in the clinical target volume (CTV), type, thickness and density of biomaterial should be considered to avoid dose differences. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  11. Health service costs in Europe: cost and reimbursement of primary hip replacement in nine countries.

    PubMed

    Stargardt, Tom

    2008-01-01

    This paper assesses variations in the cost of primary hip replacement between and within nine member states of the European Union (EU). It also compares the cost of service with public-payer reimbursements. To do so, data on cost and reimbursement were surveyed at the micro-level in 42 hospitals in Denmark, England, France, Germany, Hungary, Italy, The Netherlands, Poland, and Spain. The total cost of treatment ranged from 1290 euros (Hungary) to 8739 euros (The Netherlands), with a mean cost of 5043 euros (STD +/- 2071 euros). The main cost drivers were found to be implants (34% of total cost on average) and ward costs (20.9% of total cost on average). A one-way random effects analysis of variance model indicated that 74.0% of variation was between and only 26% of variation was within countries. In a two-level random-intercept regression model, purchasing-power parities explained 79.4% of the explainable between-country variation, while the percentage of uncemented implants used and the number of beds explained 12.1 and 1.6% of explainable within-country variation, respectively. The large differences in cost and reimbursement between Poland, Hungary, and the other EU member states shows that primary total hip replacement is a highly relevant case for cross-border care. Copyright 2008 John Wiley & Sons, Ltd.

  12. Is hydroxyapatite a reliable fixation option in unicompartmental knee arthroplasty? A 5- to 13-year experience with the hydroxyapatite-coated unix prosthesis.

    PubMed

    Epinette, Jean-Alain; Manley, Michael T

    2008-10-01

    Hydroxyapatite-coated unicompartmental knee arthroplasty (UKA) is a debatable approach to unicompartmental knee arthritis because UKA isoften viewed as a short-term solution, at best, fora condition that will eventually require a total knee arthroplasty (TKA). Unicompartmental knee arthroplasty is a more technically demanding procedure than TKA, and appropriate patient selection, careful surgical technique, and correct choice of implant geometry are all critical components to its success. A fundamental issue surrounding UKA is whether hydroxyapatite-coated unicompartmental components can provide a long-term solution to unicondylar arthritis. We address this issue in the current study, which is based on a prospective series of 125 hydroxyapatite-coated Unix knee prostheses implanted consecutively between 1994 and 2002, with a 5-year minimum follow-up and a 13-year maximum follow-up. The results of our study indicate that uncemented hydroxyapatite-coated UKA can be successful in the long term.

  13. Deformation of the Durom Acetabular Component and Its Impact on Tribology in a Cadaveric Model—A Simulator Study

    PubMed Central

    Gu, Yanqing; Wang, Qing; Cui, Weiding; Fan, Weimin

    2012-01-01

    Background Recent studies have shown that the acetabular component frequently becomes deformed during press-fit insertion. The aim of this study was to explore the deformation of the Durom cup after implantation and to clarify the impact of deformation on wear and ion release of the Durom large head metal-on-metal (MOM) total hips in simulators. Methods Six Durom cups impacted into reamed acetabula of fresh cadavers were used as the experimental group and another 6 size-paired intact Durom cups constituted the control group. All 12 Durom MOM total hips were put through a 3 million cycle (MC) wear test in simulators. Results The 6 cups in the experimental group were all deformed, with a mean deformation of 41.78±8.86 µm. The average volumetric wear rate in the experimental group and in the control group in the first million cycle was 6.65±0.29 mm3/MC and 0.89±0.04 mm3/MC (t = 48.43, p = 0.000). The ion levels of Cr and Co in the experimental group were also higher than those in the control group before 2.0 MC. However there was no difference in the ion levels between 2.0 and 3.0 MC. Conclusions This finding implies that the non-modular acetabular component of Durom total hip prosthesis is likely to become deformed during press-fit insertion, and that the deformation will result in increased volumetric wear and increased ion release. Clinical Relevance This study was determined to explore the deformation of the Durom cup after implantation and to clarify the impact of deformation on wear and ion release of the prosthesis. Deformation of the cup after implantation increases the wear of MOM bearings and the resulting ion levels. The clinical use of the Durom large head prosthesis should be with great care. PMID:23144694

  14. Deformation of the Durom acetabular component and its impact on tribology in a cadaveric model--a simulator study.

    PubMed

    Liu, Feng; Chen, Zhefeng; Gu, Yanqing; Wang, Qing; Cui, Weiding; Fan, Weimin

    2012-01-01

    Recent studies have shown that the acetabular component frequently becomes deformed during press-fit insertion. The aim of this study was to explore the deformation of the Durom cup after implantation and to clarify the impact of deformation on wear and ion release of the Durom large head metal-on-metal (MOM) total hips in simulators. Six Durom cups impacted into reamed acetabula of fresh cadavers were used as the experimental group and another 6 size-paired intact Durom cups constituted the control group. All 12 Durom MOM total hips were put through a 3 million cycle (MC) wear test in simulators. The 6 cups in the experimental group were all deformed, with a mean deformation of 41.78 ± 8.86 µm. The average volumetric wear rate in the experimental group and in the control group in the first million cycle was 6.65 ± 0.29 mm(3)/MC and 0.89 ± 0.04 mm(3)/MC (t = 48.43, p = 0.000). The ion levels of Cr and Co in the experimental group were also higher than those in the control group before 2.0 MC. However there was no difference in the ion levels between 2.0 and 3.0 MC. This finding implies that the non-modular acetabular component of Durom total hip prosthesis is likely to become deformed during press-fit insertion, and that the deformation will result in increased volumetric wear and increased ion release. This study was determined to explore the deformation of the Durom cup after implantation and to clarify the impact of deformation on wear and ion release of the prosthesis. Deformation of the cup after implantation increases the wear of MOM bearings and the resulting ion levels. The clinical use of the Durom large head prosthesis should be with great care.

  15. Cobalt, chromium and molybdenum ions kinetics in the human body: data gained from a total hip replacement with massive third body wear of the head and neuropathy by cobalt intoxication.

    PubMed

    Pazzaglia, U E; Apostoli, P; Congiu, T; Catalani, S; Marchese, M; Zarattini, G

    2011-09-01

    A patient with a total hip replacement developed optic, acoustic and peripheral neuropathy from metal ions intoxication, due to the wear products released from the prosthesis. Subsequently the kinetics of the metal ions was studied. Massive wear and acute intoxication allowed a study of the metal ions kinetics and of EDTA treatment. Plasma and other organic fluids were saturated by each of the metal ions released from the exposed surface according to the solubility of each ion; a larger fraction of Co ions was bound within red cells, while the plasmatic fraction appeared more movable. In a patient with a prosthesis subjected to wear, the ions released are from the prosthetic and from the debris surface (spread in the body). The latter is a function of the number and size of particles. Revision of the prosthesis from the point of view of the metal ions kinetics corresponded to a reduction of the releasing surface because of debris washed out by irrigation and tissue excision; however, the metal particles spread by lymphatic circulation continued to release ions even though the source of wear had been removed. Early diagnosis of high metal wear can be ascertained with mass spectrometry and after revision high levels of metal ions can only be reduced with repeated chelating treatment. It is preferable not to revise fractured ceramic components with a polyethylene-metal articulation.

  16. Tightening force and torque of nonlocking screws in a reverse shoulder prosthesis.

    PubMed

    Terrier, A; Kochbeck, S H; Merlini, F; Gortchacow, M; Pioletti, D P; Farron, A

    2010-07-01

    Reversed shoulder arthroplasty is an accepted treatment for glenohumeral arthritis associated to rotator cuff deficiency. For most reversed shoulder prostheses, the baseplate of the glenoid component is uncemented and its primary stability is provided by a central peg and peripheral screws. Because of the importance of the primary stability for a good osteo-integration of the baseplate, the optimal fixation of the screws is crucial. In particular, the amplitude of the tightening force of the nonlocking screws is clearly associated to this stability. Since this force is unknown, it is currently not accounted for in experimental or numerical analyses. Thus, the primary goal of this work is to measure this tightening force experimentally. In addition, the tightening torque was also measured, to estimate an optimal surgical value. An experimental setup with an instrumented baseplate was developed to measure simultaneously the tightening force, tightening torque and screwing angle, of the nonlocking screws of the Aquealis reversed prosthesis. In addition, the amount of bone volume around each screw was measured with a micro-CT. Measurements were performed on 6 human cadaveric scapulae. A statistically correlated relationship (p<0.05, R=0.83) was obtained between the maximal tightening force and the bone volume. The relationship between the tightening torque and the bone volume was not statistically significant. The experimental relationship presented in this paper can be used in numerical analyses to improve the baseplate fixation in the glenoid bone. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  17. The economics of using prophylactic antibiotic-loaded bone cement in total knee replacement.

    PubMed

    Gutowski, C J; Zmistowski, B M; Clyde, C T; Parvizi, J

    2014-01-01

    The rate of peri-prosthetic infection following total joint replacement continues to rise, and attempts to curb this trend have included the use of antibiotic-loaded bone cement at the time of primary surgery. We have investigated the clinical- and cost-effectiveness of the use of antibiotic-loaded cement for primary total knee replacement (TKR) by comparing the rate of infection in 3048 TKRs performed without loaded cement over a three-year period versus the incidence of infection after 4830 TKRs performed with tobramycin-loaded cement over a later period of time of a similar duration. In order to adjust for confounding factors, the rate of infection in 3347 and 4702 uncemented total hip replacements (THR) performed during the same time periods, respectively, was also examined. There were no significant differences in the characteristics of the patients in the different cohorts. The absolute rate of infection increased when antibiotic-loaded cement was used in TKR. However, this rate of increase was less than the rate of increase in infection following uncemented THR during the same period. If the rise in the rate of infection observed in THR were extrapolated to the TKR cohort, 18 additional cases of infection would have been expected to occur in the cohort receiving antibiotic-loaded cement, compared with the number observed. Depending on the type of antibiotic-loaded cement that is used, its cost in all primary TKRs ranges between USD $2112.72 and USD $112 606.67 per case of infection that is prevented.

  18. Satisfactory Results of the Exeter Revision Femoral Stem Used for Primary Total Hip Arthroplasty.

    PubMed

    Desy, Nicholas M; Johnson, Joshua D; Sierra, Rafael J

    2017-02-01

    The Exeter cemented femoral stem has demonstrated excellent clinical and radiographic outcomes as well as long-term survivorship free from aseptic loosening. A shorter revision stem (125 mm) with a 44 offset became available for the purpose of cement-in-cement revision situations. In certain cases, this shorter revision stem may be used for various primary total hip arthroplasties (THAs) where the standard length stem would require distally reaming the femoral canal. We sought to report on the early to midterm results of this specific stem when used for primary THA regarding (1) clinical and radiographic outcomes, (2) complications, and (3) survivorship. Twenty-nine patients (33 hips) underwent a hybrid THA using the smaller revision Exeter cemented femoral stem. Twenty-five patients (28 hips) had at least 2 years of follow-up and were assessed for clinical and radiographic outcomes. All 33 hips were included in the analysis of complications and survivorship. The Kaplan-Meier survivorship was performed using revision for all causes and for aseptic loosening as the end points. The average clinical follow-up was 4 years (range, 2-7). Harris Hip Scores improved from a mean preoperative value of 56 (range, 23-96) to 90 (range, 51-100) at the latest follow-up. All patients demonstrated superior cement mantles with no signs of loosening. One patient suffered a B2 periprosthetic fracture and 1 patient experienced 2 episodes of instability. The 5-year Kaplan-Meier survivorship was 96.7% for all causes of revision and was 100% using aseptic loosening as the end point. The shorter Exeter revision cemented femoral stem has favorable early to midterm clinical and radiographic outcomes when used for primary THA with a low complication rate and is a viable option in patients with narrow femoral canals where uncemented stem fixation is not desired. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Design Optimization of a Magnetically Levitated Electromagnetic Vibration Energy Harvester for Body Motion

    NASA Astrophysics Data System (ADS)

    Pancharoen, K.; Zhu, D.; Beeby, S. P.

    2016-11-01

    This paper presents a magnetically levitated electromagnetic vibration energy harvester based on magnet arrays. It has a nonlinear response that extends the operating bandwidth and enhances the power output of the harvesting device. The harvester is designed to be embedded in a hip prosthesis and harvest energy from low frequency movements (< 5 Hz) associated with human motion. The design optimization is performed using Comsol simulation considering the constraints on size of the harvester and low operating frequency. The output voltage across the optimal load 3.5kΩ generated from hip movement is 0.137 Volts during walking and 0.38 Volts during running. The power output harvested from hip movement during walking and running is 5.35 μW and 41.36 μW respectively..

  20. Integration of multi-objective structural optimization into cementless hip prosthesis design: Improved Austin-Moore model.

    PubMed

    Kharmanda, G

    2016-11-01

    A new strategy of multi-objective structural optimization is integrated into Austin-Moore prosthesis in order to improve its performance. The new resulting model is so-called Improved Austin-Moore. The topology optimization is considered as a conceptual design stage to sketch several kinds of hollow stems according to the daily loading cases. The shape optimization presents the detailed design stage considering several objectives. Here, A new multiplicative formulation is proposed as a performance scale in order to define the best compromise between several requirements. Numerical applications on 2D and 3D problems are carried out to show the advantages of the proposed model.

  1. Tribology and total hip joint replacement: current concepts in mechanical simulation.

    PubMed

    Affatato, S; Spinelli, M; Zavalloni, M; Mazzega-Fabbro, C; Viceconti, M

    2008-12-01

    Interest in the rheology and effects of interacting surfaces is as ancient as man. This subject can be represented by a recently coined word: tribology. This term is derived from the Greek word "tribos" and means the "science of rubbing". Friction, lubrication, and wear mechanism in the common English language means the precise field of interest of tribology. Wear of total hip prosthesis is a significant clinical problem that involves, nowadays, a too high a number of patients. In order to acquire further knowledge on the tribological phenomena that involve hip prosthesis wear tests are conducted on employed materials to extend lifetime of orthopaedic implants. The most basic type of test device is the material wear machine, however, a more advanced one may more accurately reproduce some of the in vivo conditions. Typically, these apparatus are called simulators, and, while there is no absolute definition of a joint simulator, its description as a mechanical rig used to test a joint replacement, under conditions approximating those occurring in the human body, is acceptable. Simulator tests, moreover, can be used to conduct accelerated protocols that replicate/simulate particularly extreme conditions, thus establishing the limits of performance for the material. Simulators vary in their level of sophistication and the international literature reveals many interpretations of the design of machines used for joint replacement testing. This paper aims to review the current state of the art of the hip joint simulators worldwide. This is specified through a schematic overview by describing, in particular, constructive solutions adopted to reproduce in vivo conditions. An exhaustive commentary on the evolution and actually existing simulation standards is proposed by the authors. The need of a shared protocol among research laboratories all over the world could lead to a consensus conference.

  2. Optimization simulated injection molding process for ultrahigh molecular weight polyethylene nanocomposite hip liner using response surface methodology and simulation of mechanical behavior.

    PubMed

    Heidari, Behzad Shiroud; Davachi, Seyed Mohammad; Moghaddam, Amin Hedayati; Seyfi, Javad; Hejazi, Iman; Sahraeian, Razi; Rashedi, Hamid

    2018-05-01

    In this study, injection molding process of ultrahigh molecular weight polyethylene (UHMWPE) reinforced with nano-hydroxyapatite (nHA) was simulated and optimized through minimizing the shrinkage and warpage of the hip liners as an essential part of a hip prosthesis. Fractional factorial design (FFD) was applied to the design of the experiment, modeling, and optimizing the shrinkage and warpage of UHMWPE/nHA composite liners. The Analysis of variance (ANOVA) was applied to find the importance of operative parameters and their effects. In this experiment, seven input parameters were surveyed, including mold temperature (A), melt temperature (B), injection time (C), packing time (D), packing pressure (E), coolant temperature (F), and type of liner (G). Two models were capable of predicting warpage and volumetric shrinkage (%) in different conditions with R 2 of 0.9949 and 0.9989, respectively. According to the models, the optimized values of warpage and volumetric shrinkage are 0.287222 mm and 13.6613%, respectively. Meanwhile, a finite element analysis (FE analysis) was also carried out to examine the stress distribution in liners under the force values of demanding and daily activities. The Von-Mises stress distribution showed that both of the liners can be applied to all activities with no failure. However, UHMWPE/nHA liner is more resistant to the highest loads than UHMWPE liner due to the effect of nHA in the nanocomposite. Finally, according to the results of injection molding simulations, optimization, structural analysis as well as the tensile strength and wear resistance, UHMWPE/nHA liner is recommended for the production of a hip prosthesis. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. HipMatch: an object-oriented cross-platform program for accurate determination of cup orientation using 2D-3D registration of single standard X-ray radiograph and a CT volume.

    PubMed

    Zheng, Guoyan; Zhang, Xuan; Steppacher, Simon D; Murphy, Stephen B; Siebenrock, Klaus A; Tannast, Moritz

    2009-09-01

    The widely used procedure of evaluation of cup orientation following total hip arthroplasty using single standard anteroposterior (AP) radiograph is known inaccurate, largely due to the wide variability in individual pelvic orientation relative to X-ray plate. 2D-3D image registration methods have been introduced for an accurate determination of the post-operative cup alignment with respect to an anatomical reference extracted from the CT data. Although encouraging results have been reported, their extensive usage in clinical routine is still limited. This may be explained by their requirement of a CAD model of the prosthesis, which is often difficult to be organized from the manufacturer due to the proprietary issue, and by their requirement of either multiple radiographs or a radiograph-specific calibration, both of which are not available for most retrospective studies. To address these issues, we developed and validated an object-oriented cross-platform program called "HipMatch" where a hybrid 2D-3D registration scheme combining an iterative landmark-to-ray registration with a 2D-3D intensity-based registration was implemented to estimate a rigid transformation between a pre-operative CT volume and the post-operative X-ray radiograph for a precise estimation of cup alignment. No CAD model of the prosthesis is required. Quantitative and qualitative results evaluated on cadaveric and clinical datasets are given, which indicate the robustness and the accuracy of the program. HipMatch is written in object-oriented programming language C++ using cross-platform software Qt (TrollTech, Oslo, Norway), VTK, and Coin3D and is transportable to any platform.

  4. Detection of total hip prostheses at airport security checkpoints: how has heightened security affected patients?

    PubMed

    Johnson, Aaron J; Naziri, Qais; Hooper, Hasan A; Mont, Michael A

    2012-04-04

    The sensitivity of airport security screening measures has increased substantially during the past decade, but few reports have examined how this affects patients who have undergone hip arthroplasty. The purpose of this study was to determine the experiences of patients who had hip prostheses and who passed through airport security screenings. A consecutive series of 250 patients who presented to the office of a high-volume surgeon were asked whether they had had a hip prosthesis for at least one year and, if so, whether they had flown on a commercial airline within the past year. Patients who responded affirmatively to both questions were asked to complete a written survey that included questions about which joint(s) had been replaced, the number of encounters with airport security, the frequency and location of metal detector activation, any additional screening procedures that were utilized, whether security officials requested documentation regarding the prosthesis, the degree of inconvenience, and other relevant information. Of the 143 patients with hip replacements who traveled by air, 120 (84%) reported triggering the alarm and required wanding with a handheld detector. Twenty-five of these patients reported subsequently having to undergo further inspection, including additional wanding, being patted down, and in two cases having to undress in a private room to show the incision. Ninety-nine (69%) of the 143 patients reported that the prosthetic joint caused an inconvenience while traveling. This study provides interesting and critical information that allows physicians to understand the real-world implications of implanted orthopaedic devices for patients who are traveling where there has been heightened security since September 11, 2001. Patients should be counseled that they should expect delays and be prepared for such inconveniences, but that these are often only momentary. This information could relieve some anxiety and concerns that patients may have prior to traveling.

  5. Early subsidence of shape-closed hip arthroplasty stems is associated with late revision. A systematic review and meta-analysis of 24 RSA studies and 56 survival studies.

    PubMed

    van der Voort, Paul; Pijls, Bart G; Nieuwenhuijse, Marc J; Jasper, Jorrit; Fiocco, Marta; Plevier, Josepha W M; Middeldorp, Saskia; Valstar, Edward R; Nelissen, Rob G H H

    2015-01-01

    Few studies have addressed the association between early migration of femoral stems and late aseptic revision in total hip arthroplasty. We performed a meta-regression analysis on 2 parallel systematic reviews and meta-analyses to determine the association between early migration and late aseptic revision of femoral stems. Of the 2 reviews, one covered early migration data obtained from radiostereometric analysis (RSA) studies and the other covered long-term aseptic revision rates obtained from survival studies with endpoint revision for aseptic loosening. Stems were stratified according to the design concept: cemented shape-closed, cemented force-closed, and uncemented. A weighted regression model was used to assess the association between early migration and late aseptic revision, and to correct for confounders. Thresholds for acceptable and unacceptable migration were determined in accordance with the national joint registries (≤ 5% revision at 10 years) and the NICE criteria (≤ 10% revision at 10 years). 24 studies (731 stems) were included in the RSA review and 56 studies (20,599 stems) were included in the survival analysis review. Combining both reviews for the 3 design concepts showed that for every 0.1-mm increase in 2-year subsidence, as measured with RSA, there was a 4% increase in revision rate for the shape-closed stem designs. This association remained after correction for age, sex, diagnosis, hospital type, continent, and study quality. The threshold for acceptable migration of shape-closed designs was defined at 0.15 mm; stems subsiding less than 0.15 mm in 2 years had revision rates of less than 5% at 10 years, while stems exceeding 0.15 mm subsidence had revision rates of more than 5%. There was a clinically relevant association between early subsidence of shape-closed femoral stems and late revision for aseptic loosening. This association can be used to assess the safety of shape-closed stem designs. The published research is not sufficient to allow us to make any conclusions regarding such an association for the force-closed and uncemented stems.

  6. Acetabular Cup Revision.

    PubMed

    Kim, Young-Ho

    2017-09-01

    The use of acetabular cup revision arthroplasty is on the rise as demands for total hip arthroplasty, improved life expectancies, and the need for individual activity increase. For an acetabular cup revision to be successful, the cup should gain stable fixation within the remaining supportive bone of the acetabulum. Since the patient's remaining supportive acetabular bone stock plays an important role in the success of revision, accurate classification of the degree of acetabular bone defect is necessary. The Paprosky classification system is most commonly used when determining the location and degree of acetabular bone loss. Common treatment options include: acetabular liner exchange, high hip center, oblong cup, trabecular metal cup with augment, bipolar cup, bulk structural graft, cemented cup, uncemented cup including jumbo cup, acetabular reinforcement device (cage), trabecular metal cup cage. The optimal treatment option is dependent upon the degree of the discontinuity, the amount of available bone stock and the likelihood of achieving stable fixation upon supportive host bone. To achieve successful acetabular cup revision, accurate evaluation of bone defect preoperatively and intraoperatively, proper choice of method of acetabular revision according to the evaluation of acetabular bone deficiency, proper technique to get primary stability of implant such as precise grafting technique, and stable fixation of implant are mandatory.

  7. [Mid-Term to Long-Term Results of Revision Total Hip Arthroplasty Using the Oval-Shaped Acetabular Cup - TC Type].

    PubMed

    Šťastný, E; Trč, T; Frýdl, J; Kopečný, Z; Philippou, T; Lisý, J

    2017-01-01

    INTRODUCTION The purpose of our paper is to evaluate the mid-term to long-term results and to confirm the basic criteria of a high-quality revision implant: safe bridging of bone defects, achievement of reliable primary fixation of revision acetabular cup, achievement of good secondary stability with documentable osteointegration of cup and demonstration of remodelling of transplanted bone tissue in the area of defects and in spaces between the implant ribs. MATERIAL AND METHODS Altogether 36 patients (38 cups) were evaluated who had undergone revision hip arthroplasty in the period from 2004 to 2010. The mean follow-up was 8.2 years (5.1-11.6 years after the reimplantation, more than 10 years in 16 patients who underwent surgery). The position and osseointegration of the implant were assessed by digital radiography, the remodelling of transplanted bone tissues in the area of defects and between the implant ribs by computed tomography with reducing artefacts around the metal implant (Aquilion 64 - Toshiba Medical Systems), and for the clinical outcomes the Harris Hip Score was used. RESULTS Preoperatively, the condition of the hip joint based on the Harris Hip Score was in 30 cases evaluated as poor, in 8 patients as satisfactory. At the time of final evaluation, 8 patients achieved excellent results, in 19 patients the condition of the joint was very good (in 2 patients bilaterally), in 6 patients it was considered satisfactory and in 3 patients poor. The mean value for HHS increased from 39.5 to 84.5. Based on the radiography evaluation, in 27 patients (in 2 patients bilaterally) the osseointegration of the revision cup was good, in 8 cases with a radiolucent line of 2-4 mm in width in DeLee zone III, in one case proximal migration of the cup occurred caused by deep infection. The informed consent form for pelvic CT was signed by 25 patients of our cohort. Remodelling of bone tissue in the space between the ribs of the implant was always detected, the presence of bone cysts was not reported, the bone defects following the application of autologous spongioplasty in the monitored patients were healed. In 6 patients, an ingrowth of fibrous tissue of 2-4 mm in width in the convexity of the cup was detected. The mean survival of the revision oval-shaped cup - TC type with a follow-up of 8.2 years after the reimplantation based on Kaplan-Meier analysis was 91.4 %. DISCUSSION The number of revision total hip arthroplasties due to a younger age of patients who undergo alloplasty keeps growing. The choice of a revision implant should always match the intraoperative finding and the bone tissue quality. The standard uncemented implants with osteoactive surface can be opted for when anterior and posterior column of the acetabulum are intact (IIA and IIB according to Paprosky). Starting from type IIC, also the proximal part of acetabulum shall be considered. At our department, preference is given to the revision cup - TC type. The oval shape facilitates a lower degree of bone resection and easier restoration of the anatomical centre of rotation. Careful debridement of granulating and necrotic tissue, thorough treatment of bone defects and osteoactive surface of implants in case of adequate primary fixation of the cup substantially contribute to the quality of its osseointegration. Greater rigidity of fixation verified by pull-out tests enables to insert angular stable screws into the gaps in the proximal part of the cup. There is still room for improvement in treating the bone defect. The application of allogenic bone grafts into the defects and spaces between the ribs of the TC cup is more challenging than the use of augmentation in the systems with trabecular titanium. Based on the evaluation of CT scans, remodelling of the transplanted bone occurs, therefore the defect zone is reduced. CONCLUSIONS The oval-shaped uncemented cup - type TC meets the requirements placed on a state-of the art revision implant, moreover its specific construction helps improve the conditions where another re-operation of acetabulum is necessary. By evaluating mid-term to long-term results of non-homogenous group of 36 patients (38 cups) we have obtained data on joint function comparable to similar groups with revision uncemented implants presented in our and foreign literature. Key words: revision oval-shaped cup, bone remodelling, pull-out tests, angular stable screws, computed tomography.

  8. A Scandinavian experience of register collaboration: the Nordic Arthroplasty Register Association (NARA).

    PubMed

    Havelin, Leif I; Robertsson, Otto; Fenstad, Anne M; Overgaard, Søren; Garellick, Göran; Furnes, Ove

    2011-12-21

    The Nordic (Scandinavian) countries have had working arthroplasty registers for several years. However, the small numbers of inhabitants and the conformity within each country with respect to preferred prosthesis brands and techniques have limited register research. A collaboration called NARA (Nordic Arthroplasty Register Association) was started in 2007, resulting in a common database for Denmark, Norway, and Sweden with regard to hip replacements in 2008 and primary knee replacements in 2009. Finland joined the project in 2010. A code set was defined for the parameters that all registers had in common, and data were re-coded, within each national register, according to the common definitions. After de-identification of the patients, the anonymous data were merged into a common database. The first study based on this common database included 280,201 hip arthroplasties and the second, 151,814 knee arthroplasties. Kaplan-Meier and Cox multiple regression analyses, with adjustment for age, sex, and diagnosis, were used to calculate prosthesis survival, with any revision as the end point. In later studies, specific reasons for revision were also used as end points. We found differences among the countries concerning patient demographics, preferred surgical approaches, fixation methods, and prosthesis brands. Prosthesis survival was best in Sweden, where cement implant fixation was used more commonly than it was in the other countries. As the comparison of national results was one of the main initial aims of this collaboration, only parameters and data that all three registers could deliver were included in the database. Compared with each separate register, this combined register resulted in reduced numbers of parameters and details. In future collaborations of registers with a focus on comparing the performances of prostheses and articulations, we should probably include only the data needed specifically for the predetermined purposes, from registers that can deliver these data, rather than compiling all data from all registers that are willing to participate.

  9. Are Canadian prostheses used? A long-term experience.

    PubMed

    Fernández, A; Formigo, J

    2005-08-01

    The Canadian prosthesis is indicated for the more proximal levels of amputation of the lower limb (very short trans-femoral, hip disarticulation and hemipelvectomy cases); it is frequently rejected by many patients for different reasons (awkwardness, intolerance of the socket, excessive energy expenditure to ambulate among others). The objective was to analyse the use or rejection of Canadian prostheses (n = 23) after an 8-year follow-up study (range: 2 -16 years). The sample consisted of 52% men and 48% women, and the average age at the time of amputation was 52.26 +/- 19.71 SD years (range: 1-74 years). The most frequent aetiology was malignant tumour (56.5%). Eight of the subjects continued to use the prosthesis through the entire study (34.7%). Gender, age, and aetiology were not significant determinants of use. The daily use was 12.5 h per day. The rejection of the Canadian prosthesis was after 20 months of use (range: 2-48 months), and the main reasons were death (all tumour causes), intolerance to the socket, or difficulty in ambulation. In conclusion, many years after their discharge from rehabilitation services, more than one-third of the sample (34.7%) were wearers of the Canadian prosthesis.

  10. Melorheostosis--an unusual cause of amputation.

    PubMed

    Graham, L E; Parke, R C

    2005-04-01

    A 24-year-old female developed, in infancy, progressive right upper and lower limb muscle and soft tissue contractures and had a diagnosis of melorheostosis made on X-ray and pathological specimens. At the age of 11 years she began to have pain in the right hip and lower limb and this later became the dominant feature. She ultimately required amputation through the right hip joint and prosthetic fitting. She now has independent mobility with her prosthesis and has had no recurrence of pain. Her right arm remains flexed, shortened and contracted, but some hand function is retained. A review of the medical literature is discussed.

  11. Experimental and Monte Carlo evaluation of Eclipse treatment planning system for effects on dose distribution of the hip prostheses

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Çatlı, Serap, E-mail: serapcatli@hotmail.com; Tanır, Güneş

    2013-10-01

    The present study aimed to investigate the effects of titanium, titanium alloy, and stainless steel hip prostheses on dose distribution based on the Monte Carlo simulation method, as well as the accuracy of the Eclipse treatment planning system (TPS) at 6 and 18 MV photon energies. In the present study the pencil beam convolution (PBC) method implemented in the Eclipse TPS was compared to the Monte Carlo method and ionization chamber measurements. The present findings show that if high-Z material is used in prosthesis, large dose changes can occur due to scattering. The variance in dose observed in the presentmore » study was dependent on material type, density, and atomic number, as well as photon energy; as photon energy increased back scattering decreased. The dose perturbation effect of hip prostheses was significant and could not be predicted accurately by the PBC method for hip prostheses. The findings show that for accurate dose calculation the Monte Carlo-based TPS should be used in patients with hip prostheses.« less

  12. Effect of cup inclination on predicted contact stress-induced volumetric wear in total hip replacement.

    PubMed

    Rijavec, B; Košak, R; Daniel, M; Kralj-Iglič, V; Dolinar, D

    2015-01-01

    In order to increase the lifetime of the total hip endoprosthesis, it is necessary to understand mechanisms leading to its failure. In this work, we address volumetric wear of the artificial cup, in particular the effect of its inclination with respect to the vertical. Volumetric wear was calculated by using mathematical models for resultant hip force, contact stress and penetration of the prosthesis head into the cup. Relevance of the dependence of volumetric wear on inclination of the cup (its abduction angle ϑA) was assessed by the results of 95 hips with implanted endoprosthesis. Geometrical parameters obtained from standard antero-posterior radiographs were taken as input data. Volumetric wear decreases with increasing cup abduction angle ϑA. The correlation within the population of 95 hips was statistically significant (P = 0.006). Large cup abduction angle minimises predicted volumetric wear but may increase the risk for dislocation of the artificial head from the cup in the one-legged stance. Cup abduction angle and direction of the resultant hip force may compensate each other to achieve optimal position of the cup with respect to wear and dislocation in the one-legged stance for a particular patient.

  13. Cementless fixation of "isoelastic" hip endoprostheses manufactured from plastic materials.

    PubMed

    Morscher, E W; Dick, W

    1983-06-01

    Nine years of clinical experience with an "isoelastic" shaft prosthesis manufactured using polyacetal resin reveal that for the transmission of forces from the pelvis through the femoral head and neck into the femoral shaft, some rigidity of the proximal part of the prosthesis is necessary. The object is to eliminate micromovements, which lead to bone resorption and implant loosening. However, elasticity greater than that present in metallic implants prevents stress concentrations and disuse stress protection atrophy of the bone. Greater elasticity of the prosthesis, which can be achieved by plastic materials, makes possible a more even, harmonious distribution of the forces transmitted from the implant to the bone and vice versa. A more elastic implant can also act as a better shock absorber than a rigid one. The results in 627 cementless polyethylene cups after a maximum observation period of 5.5 years reveal good incorporation and no aseptic loosening. Especially favorable results occurred in 61 cases by replacing loosened cemented cups with bone grafts and cementless polyethylene cups. On the femoral shaft side too high an elasticity in the proximal part of the prosthesis led to bone resorption and loosening with the first model of the prosthesis. By reinforcing the proximal part of the femoral component, much better results were obtained. The isoelastic femoral shaft, however, is in an early stage of experimentation.

  14. [Principles of management of periprosthetic fractures].

    PubMed

    Röderer, G; Gebhard, F; Scola, A

    2016-03-01

    The increasing numbers of primary total hip and knee replacements have subsequently led to growing rates of periprosthetic fractures. In many cases geriatric patients with osteopenia or osteoporotic bone quality are affected. The goal of treatment is the retention or reconstruction of joint function using open reduction and internal fixation or a revision prosthesis. The aim of this article is a description of the basic principles of treatment of periprosthetic fractures of the lower extremities. An exact description of the fracture using current classification systems with imaging diagnostics is mandatory. This also includes an assessment of the stability of the prosthesis. In the case of a stable prosthesis and a good bone stock open reduction and internal fixation should be performed. In these cases locking plates are standard procedure. If fracture reduction is possible minimally invasive procedures can be performed which help to reduce the surgical trauma and accelerate rehabilitation. If the prosthesis is loose it has to be exchanged for a revision implant. If vast bony defects result they can be augmented using wedges. Conservative treatment plays only a subordinate role in selected cases. Periprosthetic fractures show an increasing incidence and occur more frequently in the geriatric patient population. Due to comorbidities and poor bone quality surgical treatment is a challenge. The fracture must be exactly classified using the appropriate classification system in order to clarify if the prosthesis can be retained or if it has to be exchanged.

  15. Management bone loss of the proximal femur in revision hip arthroplasty: Update on reconstructive options

    PubMed Central

    Sakellariou, Vasileios I; Babis, George C

    2014-01-01

    The number of revision total hip arthroplasties is expected to rise as the indications for arthroplasty will expand due to the aging population. The prevalence of extensive proximal femoral bone loss is expected to increase subsequently. The etiology of bone loss from the proximal femur after total hip arthroplasty is multifactorial. Stress shielding, massive osteolysis, extensive loosening and history of multiple surgeries consist the most common etiologies. Reconstruction of extensive bone loss of the proximal femur during a revision hip arthroplasty is a major challenge for even the most experienced orthopaedic surgeon. The amount of femoral bone loss and the bone quality of the remaining metaphyseal and diaphyseal bone dictate the selection of appropriate reconstructive option. These include the use of impaction allografting, distal press-fit fixation, allograft-prosthesis composites and tumor megaprostheses. This review article is a concise review of the current literature and provides an algorithmic approach for reconstruction of different types of proximal femoral bone defects. PMID:25405090

  16. Hip prostheses in young adults. Surface prostheses and short-stem prostheses.

    PubMed

    Gallart, X; Riba, J; Fernández-Valencia, J A; Bori, G; Muñoz-Mahamud, E; Combalia, A

    The poor results obtained in young patients when using a conventional prosthesis led to the resurgence of hip resurfacing to find less invasive implants for the bone. Young patients present a demand for additional activity, which makes them a serious challenge for the survival of implants. In addition, new information technologies contribute decisively to the preference for non-cemented prostheses. Maintaining quality of life, preserving the bone and soft tissues, as well as achieving a very stable implant, are the goals of every hip orthopaedic surgeon for these patients. The results in research point to the use of smaller prostheses, which use the metaphyseal zone more and less the diaphyseal zone, and hence the large number of the abovementioned short stem prostheses. Both models are principally indicated in the young adult. Their revision should be a more simple operation, but this is only true for hip resurfacing, not for short stems. Copyright © 2017 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

  17. Robert Merle d’Aubigné, 1900–1989

    PubMed Central

    Biau, David J.

    2008-01-01

    This biographical sketch of R. Merle d’Aubigné corresponds to the historic text, The Classic: Functional Results of Hip Arthroplasty with Acrylic Prosthesis, available at DOI 10.1007/s11999-008-0572-1. Electronic supplementary material The online version of this article (doi:10.1007/s11999-008-0571-2) contains supplementary material, which is available to authorized users. PMID:18941853

  18. In-situ electrochemical study of interaction of tribology and corrosion in artificial hip prosthesis simulators.

    PubMed

    Yan, Yu; Dowson, Duncan; Neville, Anne

    2013-02-01

    The second generation Metal-on-Metal (MoM) hip replacements have been considered as an alternative to commonly used Polyethylene-on-Metal (PoM) joint prostheses due to polyethylene wear debris induced osteolysis. However, the role of corrosion and the biofilm formed under tribological contact are still not fully understood. Enhanced metal ion concentrations have been reported widely from hair, blood and urine samples of patients who received metal hip replacements and in isolated cases when abnormally high levels have caused adverse local tissue reactions. An understanding of the origin of metal ions is really important in order to design alloys for reduced ion release. Reciprocating pin-on-plate wear tester is a standard instrument to assess the interaction of corrosion and wear. However, more realistic hip simulator can provide a better understanding of tribocorrosion process for hip implants. It is very important to instrument the conventional hip simulator to enable electrochemical measurements. In this study, simple reciprocating pin-on-plate wear tests and hip simulator tests were compared. It was found that metal ions originated from two sources: (a) a depassivation of the contacting surfaces due to tribology (rubbing) and (b) corrosion of nano-sized wear particles generated from the contacting surfaces. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. A 2- to 7-Year Follow-Up of a Modular Iliac Screw Cup in Major Acetabular Defects: Clinical, Radiographic and Survivorship Analysis With Comparison to the Literature.

    PubMed

    Cadossi, Matteo; Garcia, Flávio Luís; Sambri, Andrea; Andreoli, Isabella; Dallari, Dante; Pignatti, Giovanni

    2017-01-01

    Inadequate acetabular bone stock is a major issue in total hip arthroplasty, and several treatment options are available. Stemmed cups have been used in this scenario with variable results. A novel modular polyaxial uncemented iliac screw cup (HERM-BS-Sansone cup-Citieffe s.r.l., Calderara di Reno, Bologna, Italy) has been recently introduced to overcome the drawbacks of stemmed cups. In this retrospective study, we report the results of this cup in patients with large acetabular bone defects at 2- to 7-year follow-up. We evaluated a consecutive series of 121 hips (118 revisions and 3 complex primary arthroplasties) treated with this novel cup at a mean follow-up of 46 months. Kaplan-Meier survival analysis was performed with implant revision for any reason as a primary end point. Further survival analysis was performed excluding septic failures. Clinical outcome was assessed with the Harris Hip Score. There had been 7 reoperations: 1 for aseptic loosening, 5 for deep infection, and 1 for recurrent dislocation. In 5 cases, the cup was removed; estimated survival rate at 5-year follow-up with implant removal for any reason was 95.6% (95% confidence interval = 91-99), and 98.3% (95% CI = 96-100) excluding those failed for infection. Mean Harris Hip Score at latest follow-up was 77 points (range, 44-95; standard deviation = 11.9). The present findings show the short-term efficacy of the iliac screw cup with respect to implant survival. A longer follow-up and a larger number of patients are necessary to confirm the encouraging preliminary results. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Finite element analysis of 2-Station hip himulator

    NASA Astrophysics Data System (ADS)

    Fazli, M. I. M.; Yahya, A.; Shahrom, A.; Nawawi, S. W.; Zainudin, M. R.; Nazarudin, M. S.

    2017-10-01

    This paper presented the analysis of materials and design architecture of 2-station hip simulator. Hip simulator is a machine used to conduct the joint and wear test of hip prosthetic. In earlier work, the hip simulator was modified and some improvement were made by using SolidWorks software. The simulator consists of 3DOF which controlled by separate stepper motor and a static load that set up by manual method in each station. In this work, finite element analysis (FEA) of hip simulator was implemented to analyse the structure of the design and selected materials used for simulator component. The analysis is completed based on two categories which are safety factor and stress tests. Both design drawing and FEA was done using SolidWorks software. The study of the two categories is performed by applying the peak load up to 4000N on the main frame that is embedded with metal-on-metal hip prosthesis. From FEA, the value of safety factor and degree of stress formation are successfully obtained. All the components exceed the value of 2 for safety factor analysis while the degree of stress formation shows higher value compare to the yield strength of the material. With this results, it provides information regarding part of simulator which are susceptible to destruct. Besides, the results could be used for design improvement and certify the stability of the hip simulator in real application.

  1. Cemented or cementless humeral fixation in reverse total shoulder arthroplasty? a systematic review.

    PubMed

    Phadnis, J; Huang, T; Watts, A; Krishnan, J; Bain, G I

    2016-01-01

    To date, there is insufficient evidence available to compare the outcome of cemented and uncemented fixation of the humeral stem in reverse shoulder arthroplasty (RSA). A systemic review comprising 41 clinical studies was performed to compare the functional outcome and rate of complications of cemented and uncemented stems in RSA. These included 1455 cemented and 329 uncemented shoulders. The clinical characteristics of the two groups were similar. Variables were compared using pooled frequency-weighted means and relative risk ratios (RR). Uncemented stems had a significantly higher incidence of early humeral stem migration (p < 0.001, RR 18.1, 95% confidence interval (CI) 5.0 to 65.2) and non-progressive radiolucent lines (p < 0.001, RR 2.4, 95% CI 1.7 to 3.4), but a significantly lower incidence of post-operative fractures of the acromion compared with cemented stems (p = 0.004, RR 14.3, 95% CI 0.9 to 232.8). There was no difference in the risk of stem loosening or revision between the groups. The cemented stems had a greater relative risk of infection (RR 3.3, 95% CI 0.8 to 13.7), nerve injury (RR 5.7, 95% CI 0.7 to 41.5) and thromboembolism (RR 3.9, 95% CI 0.2 to 66.6). The functional outcome and range of movement were equivalent in the two groups. RSA performed with an uncemented stem gives them equivalent functional outcome and a better complication profile than with a cemented stem. The natural history and clinical relevance of early stem migration and radiolucent lines found with uncemented stems requires further long-term study. This study demonstrates that uncemented stems have at least equivalent clinical and radiographic outcomes compared with cemented stems when used for reverse total shoulder arthroplasty. ©2016 The British Editorial Society of Bone & Joint Surgery.

  2. Migration and head penetration of Vitamin-E diffused cemented polyethylene cup compared to standard cemented cup in total hip arthroplasty: study protocol for a randomised, double-blind, controlled trial (E1 HIP).

    PubMed

    Sköldenberg, Olof; Rysinska, Agata; Chammout, Ghazi; Salemyr, Mats; Muren, Olle; Bodén, Henrik; Eisler, Thomas

    2016-07-07

    In vitro, Vitamin-E-diffused, highly cross-linked polyethylene (PE) has been shown to have superior wear resistance and improved mechanical properties when compared to those of standard highly cross-linked PE liners used in total hip arthroplasty (THA). The aim of the study is to evaluate the safety of a new cemented acetabular cup with Vitamin-E-doped PE regarding migration, head penetration and clinical results. In this single-centre, double-blinded, randomised controlled trial, we will include 50 patients with primary hip osteoarthritis scheduled for THA and randomise them in a 1:1 ratio to a cemented cup with either argon gas-sterilised PE (control group) or Vitamin-E-diffused PE (vitamin-e group). All patients and the assessor of the primary outcome will be blinded and the same uncemented stem will be used for all participants. The primary end point will be proximal migration of the cup at 2 years after surgery measured with radiostereometry. Secondary end points include proximal migration at other follow-ups, total migration, femoral head penetration, clinical outcome scores and hip-related complications. Patients will be followed up at 3 months and at 1, 2, 5 and 10 years postoperatively. Results will be analysed using 95% CIs for the effect size. A regression model will also be used to adjust for stratification factors. The ethical committee at Karolinska Institutet has approved the study. The first results from the study will be disseminated to the medical community via presentations and publications in relevant medical journals when the last patient included has been followed up for 2 years. NCT02254980. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  3. Infection after primary hip arthroplasty

    PubMed Central

    2011-01-01

    Background and purpose The aim of the present study was to assess incidence of and risk factors for infection after hip arthroplasty in data from 3 national health registries. We investigated differences in risk patterns between surgical site infection (SSI) and revision due to infection after primary total hip arthroplasty (THA) and hemiarthroplasty (HA). Materials and methods This observational study was based on prospective data from 2005–2009 on primary THAs and HAs from the Norwegian Arthroplasty Register (NAR), the Norwegian Hip Fracture Register (NHFR), and the Norwegian Surveillance System for Healthcare–Associated Infections (NOIS). The Norwegian Patient Register (NPR) was used for evaluation of case reporting. Cox regression analyses were performed with revision due to infection as endpoint for data from the NAR and the NHFR, and with SSI as the endpoint for data from the NOIS. Results The 1–year incidence of SSI in the NOIS was 3.0% after THA (167/5,540) and 7.3% after HA (103/1,416). The 1–year incidence of revision due to infection was 0.7% for THAs in the NAR (182/24,512) and 1.5% for HAs in the NHFR (128/8,262). Risk factors for SSI after THA were advanced age, ASA class higher than 2, and short duration of surgery. For THA, the risk factors for revision due to infection were male sex, advanced age, ASA class higher than 1, emergency surgery, uncemented fixation, and a National Nosocomial Infection Surveillance (NNIS) risk index of 2 or more. For HAs inserted after fracture, age less than 60 and short duration of surgery were risk factors of revision due to infection. Interpretation The incidences of SSI and revision due to infection after primary hip replacements in Norway are similar to those in other countries. There may be differences in risk pattern between SSI and revision due to infection after arthroplasty. The risk patterns for revision due to infection appear to be different for HA and THA. PMID:22066562

  4. Migration and head penetration of Vitamin-E diffused cemented polyethylene cup compared to standard cemented cup in total hip arthroplasty: study protocol for a randomised, double-blind, controlled trial (E1 HIP)

    PubMed Central

    Sköldenberg, Olof; Rysinska, Agata; Chammout, Ghazi; Salemyr, Mats; Muren, Olle; Bodén, Henrik; Eisler, Thomas

    2016-01-01

    Introduction In vitro, Vitamin-E-diffused, highly cross-linked polyethylene (PE) has been shown to have superior wear resistance and improved mechanical properties when compared to those of standard highly cross-linked PE liners used in total hip arthroplasty (THA). The aim of the study is to evaluate the safety of a new cemented acetabular cup with Vitamin-E-doped PE regarding migration, head penetration and clinical results. Methods and analysis In this single-centre, double-blinded, randomised controlled trial, we will include 50 patients with primary hip osteoarthritis scheduled for THA and randomise them in a 1:1 ratio to a cemented cup with either argon gas-sterilised PE (control group) or Vitamin-E-diffused PE (vitamin-e group). All patients and the assessor of the primary outcome will be blinded and the same uncemented stem will be used for all participants. The primary end point will be proximal migration of the cup at 2 years after surgery measured with radiostereometry. Secondary end points include proximal migration at other follow-ups, total migration, femoral head penetration, clinical outcome scores and hip-related complications. Patients will be followed up at 3 months and at 1, 2, 5 and 10 years postoperatively. Results Results will be analysed using 95% CIs for the effect size. A regression model will also be used to adjust for stratification factors. Ethics and dissemination The ethical committee at Karolinska Institutet has approved the study. The first results from the study will be disseminated to the medical community via presentations and publications in relevant medical journals when the last patient included has been followed up for 2 years. Trial registration number NCT02254980. PMID:27388352

  5. Does the Dual-Mobility Hip Prosthesis Produce Better Joint Kinematics During Extreme Hip Flexion Task?

    PubMed

    Catelli, Danilo S; Kowalski, Erik; Beaulé, Paul E; Lamontagne, Mario

    2017-10-01

    Total hip arthroplasty (THA) using dual-mobility (DM) design permits larger hip range of motion. However, it is unclear how it benefits the patients during activities of daily living. The purpose was to compare kinematic variables of the operated limb between THA patients using either DM or single-bearing (SB) implants during a squat task. Twenty-four THA patients were randomly assigned to either a DM or SB implant and matched to 12 healthy controls (CTRLs). They underwent 3-dimensional squat motion analysis before and 9 months after surgery. Sagittal and frontal plane angles of the pelvis and the hip were analyzed using statistical parametric mapping. Paired analyses compared presurgery and postsurgery squat depth. Peak sagittal pelvis angle of DM was closer to normal compared with that of SB. Both implant groups had similar hip angle patterns and magnitude but significantly lower than the CTRLs. SB reached a much large hip abduction compared with the other groups. Both surgical groups had significantly worst squat depth than the CTRLs. Neither THA implant groups were able to return pelvis and hip kinematics to the level of CTRLs. The deficit of DM implants at the pelvis combined with the poorer functional scores should caution clinicians to use this implant design in active patients. SB design causes a larger hip abduction to reach their maximum squat depth. Post-THA rehabilitation should focus on improving joint range of motion and strength. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. WE-D-18A-01: Evaluation of Three Commercial Metal Artifact Reduction Methods for CT Simulations in Radiation Therapy Treatment Planning

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Huang, J; Kerns, J; Nute, J

    Purpose: To evaluate three commercial metal artifact reduction methods (MAR) in the context of radiation therapy treatment planning. Methods: Three MAR strategies were evaluated: Philips O-MAR, monochromatic imaging using Gemstone Spectral Imaging (GSI) dual energy CT, and monochromatic imaging with metal artifact reduction software (GSIMARs). The Gammex RMI 467 tissue characterization phantom with several metal rods and two anthropomorphic phantoms (pelvic phantom with hip prosthesis and head phantom with dental fillings), were scanned with and without (baseline) metals. Each MAR method was evaluated based on CT number accuracy, metal size accuracy, and reduction in the severity of streak artifacts. CTmore » number difference maps between the baseline and metal scan images were calculated, and the severity of streak artifacts was quantified using the percentage of pixels with >40 HU error (“bad pixels”). Results: Philips O-MAR generally reduced HU errors in the RMI phantom. However, increased errors and induced artifacts were observed for lung materials. GSI monochromatic 70keV images generally showed similar HU errors as 120kVp imaging, while 140keV images reduced errors. GSI-MARs systematically reduced errors compared to GSI monochromatic imaging. All imaging techniques preserved the diameter of a stainless steel rod to within ±1.6mm (2 pixels). For the hip prosthesis, O-MAR reduced the average % bad pixels from 47% to 32%. For GSI 140keV imaging, the percent of bad pixels was reduced from 37% to 29% compared to 120kVp imaging, while GSI-MARs further reduced it to 12%. For the head phantom, none of the MAR methods were particularly successful. Conclusion: The three MAR methods all improve CT images for treatment planning to some degree, but none of them are globally effective for all conditions. The MAR methods were successful for large metal implants in a homogeneous environment (hip prosthesis) but were not successful for the more complicated case of dental artifacts.« less

  7. SU-G-IeP2-03: Comparison of Dose Calculation On MAR (metal Artifact Reduction) and Non-MAR Datasets for Pelvic Patients with Hip Prosthesis and Head and Neck Patients with Dental Filling

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Huang, V; Kohli, K

    Purpose: Metal artifact reduction (MAR) software in computed tomography (CT) was previously evaluated with phantoms demonstrating the algorithm is capable of reducing metal artifacts without affecting the overall image quality. The goal of this study is to determine the dosimetric impact when calculating with CT datasets reconstructed with and without MAR software. Methods: Twelve head and neck cancer patients with dental fillings and four pelvic cancer patients with hip prosthesis were scanned with a GE Optima RT 580 CT scanner. Images were reconstructed with and without the MAR software. 6MV IMRT and VMAT plans were calculated with AAA on themore » MAR dataset until all constraints met our clinic’s guidelines. Contours from the MAR dataset were copied to the non-MAR dataset. Next, dose calculation on the non-MAR dataset was performed using the same field arrangements and fluence as the MAR plan. Conformality index, D99% and V100% to PTV were compared between MAR and non-MAR plans. Results: Differences between MAR and non-MAR plans were evaluated. For head and neck plans, the largest variations in conformality index, D99% and V100% were −3.8%, −0.9% and −2.1% respectively whereas for pelvic plans, the biggest discrepancies were −32.7%, −0.4% and -33.5% respectively. The dosimetric impact from hip prosthesis is greater because it produces more artifacts compared to dental fillings. Coverage to PTV can increase or decrease depending on the artifacts since dark streaks reduce the HU whereas bright streaks increase the HU. In the majority of the cases, PTV dose in the non-MAR plans is higher than MAR plans. Conclusion: With the presence of metals, MAR algorithm can allow more accurate delineation of targets and OARs. Dose difference between MAR and non-MAR plans depends on the proximity of the organ to the high density material, the streaking artifacts and the beam arrangements of the plan.« less

  8. Long-term outcomes following lower extremity press-fit bone-anchored prosthesis surgery: a 5-year longitudinal study protocol.

    PubMed

    Leijendekkers, Ruud A; Staal, J Bart; van Hinte, Gerben; Frölke, Jan Paul; van de Meent, Hendrik; Atsma, Femke; Nijhuis-van der Sanden, Maria W G; Hoogeboom, Thomas J

    2016-11-22

    Patients with lower extremity amputation frequently suffer from socket-related problems. This seriously limits prosthesis use, level of activity and health-related quality of life (HRQoL). An additional problem in patients with lower extremity amputation are asymmetries in gait kinematics possibly accounting for back pain. Bone-anchored prostheses (BAPs) are a possible solution for socket-related problems. Knowledge concerning the level of function, activity and HRQoL after surgery is limited. The aims of this ongoing study are to: a) describe changes in the level of function, activity, HRQoL and satisfaction over time compared to baseline before surgery; b) examine potential predictors for changes in kinematics, prosthetic use, walking ability, HRQoL, prosthesis comfort over time and level of stump pain at follow-up; c) examine potential mechanisms for change of back pain over time by identifying determinants, moderators and mediators. A prospective 5-year longitudinal study with multiple follow-ups. All adults, between May 2014 and May 2018, with lower extremity amputation receiving a press-fit BAP are enrolled consecutively. Patients with socket-related problems and trauma, tumour resection or stable vascular disease as cause of primary amputation will be included. Exclusion criteria are severe cognitive or psychiatric disorders. Follow-ups are planned at six-months, one-, two- and five-years after BAP surgery. The main study outcomes follow, in part, the ICF classification: a) level of function defined as kinematics in coronal plane, hip abductor strength, prosthetic use, back pain and stump pain; b) level of activity defined as mobility level and walking ability; c) HRQoL; d) satisfaction defined as prosthesis comfort and global perceived effect. Changes over time for the continuous outcomes and the dichotomized outcome (back pain) will be analysed using generalised estimating equations (GEE). Multivariate GEE will be used to identify potential predictors for change of coronal plane kinematics, prosthetic use, walking ability, HRQoL, prosthesis comfort and for the level of post-operative stump pain. Finally, potential mechanisms for change in back pain frequency will be explored using coronal plane kinematics as a potential determinant, stump pain as moderator and hip abductor strength as mediator. This study may identify predictors for clinically relevant outcome measures. NTR5776 . Registered 11 March 2016, retrospectively registered.

  9. Patient-specific musculoskeletal modeling of the hip joint for preoperative planning of total hip arthroplasty: A validation study based on in vivo measurements

    PubMed Central

    Schick, Fabian; Asseln, Malte; Damm, Philipp; Radermacher, Klaus

    2018-01-01

    Validation of musculoskeletal models for application in preoperative planning is still a challenging task. Ideally, the simulation results of a patient-specific musculoskeletal model are compared to corresponding in vivo measurements. Currently, the only possibility to measure in vivo joint forces is to implant an instrumented prosthesis in patients undergoing a total joint replacement. In this study, a musculoskeletal model of the AnyBody Modeling System was adapted patient-specifically and validated against the in vivo hip joint force measurements of ten subjects performing one-leg stance and level walking. The impact of four model parameters was evaluated; hip joint width, muscle strength, muscle recruitment, and type of muscle model. The smallest difference between simulated and in vivo hip joint force was achieved by using the hip joint width measured in computed tomography images, a muscle strength of 90 N/cm2, a third order polynomial muscle recruitment, and a simple muscle model. This parameter combination reached mean deviations between simulation and in vivo measurement during the peak force phase of 12% ± 14% in magnitude and 11° ± 5° in orientation for one-leg stance and 8% ± 6% in magnitude and 10° ± 5° in orientation for level walking. PMID:29649235

  10. Three-Dimensional Analysis of the Contact Pattern between the Cortical Bone and Femoral Prosthesis after Cementless Total Hip Arthroplasty

    PubMed Central

    Mishima, Hajime; Sugaya, Hisashi; Nishino, Tomofumi; Yamazaki, Masashi

    2016-01-01

    The cementless stem Excia (B. Braun, Melsungen, Germany) implant has a rectangular cross-sectional shape with back-and-forth flanges and a plasma-sprayed, dicalcium phosphate dihydrate coating from the middle to proximal portion to increase initial fixation and early bone formation. Here, the conformity of the Excia stem to the femoral canal morphology was three-dimensionally assessed using computed tomography. Forty-three patients (45 hips) were examined after primary total hip arthroplasty with a mean follow-up of 27 ± 3 months (range: 24–36 months). Spot welds occurred at zone 2 in 16 hips and at zone 6 in 24 hips, with 83% (20/24 hips) of those occurring within 3 months after surgery. First- (n = 12 hips), second- (n = 32), and third- (n = 1) degree stress shielding were observed. The stem was typically in contact with the cortical bone in the anterolateral mid-portion (100%) and posteromedial distal portions (85%). Stress shielding did not progress, even in cases where the stems were in contact with the distal portions. The anterior flange was in contact with the bone in all cases. The stability of the mid-lateral portion with the dicalcium phosphate dihydrate coating and the anterior flange may have inhibited the progression of stress shielding beyond the second degree. PMID:26881087

  11. SU-E-T-512: Evaluation of Treatment Planning Dose Calculation Accuracy at the Interface of Prosthetic Devices.

    PubMed

    Paulu, D; Alaei, P

    2012-06-01

    To evaluate the ability of treatment planning algorithm to accurately predict dose delivered at the interface of high density implanted devices. A high density (7.6 g/cc) Cobalt-Chromium-Molybdenum hip prosthesis was molded into an epoxy-based cylindrical leg phantom. The phantom was designed to be separated in half to access the prosthesis and to place the TLDs. Using MVCT to image the apparatus, a simple treatment plan was developed using the Philips Pinnacle treatment planning system. Wires were placed in the molded epoxy to allow for accurate definition of measurement sites (TLD positions) along the surface of the prosthesis. Micro-cube TLDs (1 mm 3 ) were placed at six measurement locations for which the dose had been calculated by the treatment planning system. An Elekta Synergy linear accelerator was used to deliver a 400 cGy plan to the phantom with 6 MV photons in a single fraction. A total of four 10 cm × 21 cm fields were used at 0, 90, 180, and 270 degree gantry rotations. Initial results indicate that the measured dose is 7-17% lower than the dose calculated by the treatment planning system. Further study using high energy beams are also in progress. Initial results indicate that the treatment planning system does predict the dose near a high density prosthetic device within 10-15% but underestimates the dose. The results of this study could help in designing treatment plans which would reduce the uncertainty of the dose delivered in the vicinity of prosthetic hip implants and similar devices. © 2012 American Association of Physicists in Medicine.

  12. Small and similar amounts of micromotion in an anatomical stem and a customized cementless femoral stem in regular-shaped femurs. A 5-year follow-up randomized RSA study.

    PubMed

    Nysted, Mona; Foss, Olav A; Klaksvik, Jomar; Benum, Pål; Haugan, Kristin; Husby, Otto Schnell; Aamodt, Arild

    2014-04-01

    High primary stability is important for long-term survival of uncemented femoral stems. Different stem designs are currently in use. The ABG-I is a well-documented anatomical stem with a press-fit design. The Unique stem is designed for a tight customized fit to the cortical bone of the upper femur. This implant was initially developed for patients with abnormal anatomy, but the concept can also be used in patients with normal femoral anatomy. We present 5-year radiostereometric analysis (RSA) results from a randomized study comparing the ABG-I anatomical stem with the Unique femoral stem. 100 hips with regular upper femur anatomy were randomized to either the ABG-I stem or the Unique femoral stem. RSA measurements were performed postoperatively and after 3, 6, 12, 24, and 60 months. RSA measurements from 80 hips were available for analysis at the 5-year follow-up. Small amounts of movement were observed for both stems, with no statistically significant differences between the 2 types. No improvement in long-term stability was found from using a customized stem design. However, no patients with abnormal geometry of the upper femur were included in this study.

  13. Early loosening of a press-fit cup with ceramic-on-ceramic articulation: our early results.

    PubMed

    Haverkamp, Daniël; Westerbos, Stijn; Campo, Martin M; Boonstra, Ritsert H; Rob Albers, G H; van der Vis, Harm M

    2013-12-01

    In this study, we present the short-term results of the Selexys TH+ cup with the Ceramys inlay which is a press-fit cup with a ceramic-on-ceramic articulation. (Mathys, Bettlach, Switzerland). We compared the results with a retrospective-matched control group with a Delta PF cup (Lima, Udine, Italy), which is also a press-fit cup with a ceramic-on-ceramic articulation. 257 elective hip arthroplasties with the Selexys TH+ cup in 250 patients placed in 2009 and 2010 were analyzed and compared with a control group retrospective analysis of the uncemented Delta PF cup (Lima, Udine, Italy) placed in 2007 and 2008 in 208 patients (222 hips). Surgical technique and surgeons were identical in both groups. During a follow-up period of 3-21 months, 19 aseptic loosenings (7.4 %) were found for the Selexys TH+ cup. The survival plotted by a Kaplan-Meier curve shows a 1-year survival of 87.4 %. The Lima Delta PF cup showed a 1-year survival of 99.5 %. Failure analysis showed no clear explanation for this early loosening. The Selexys TH+ cup combined with the Ceramys ceramic-on-ceramic inlay coupling show an unacceptable high early revision rate. Therefore, we advice against using this combination.

  14. Handling the procurement of prostheses for total hip replacement: description of an original value based approach and application to a real-life dataset reported in the UK

    PubMed Central

    Messori, Andrea; Trippoli, Sabrina; Marinai, Claudio

    2017-01-01

    Objectives In most European countries, innovative medical devices are not managed according to cost–utility methods, the reason being that national agencies do not generally evaluate these products. The objective of our study was to investigate the cost-utility profile of prostheses for hip replacement and to calculate a value-based score to be used in the process of procurement and tendering for these devices. Methods The first phase of our study was aimed at retrieving the studies reporting the values of QALYs, direct cost, and net monetary benefit (NMB) from patients undergoing total hip arthroplasty (THA) with different brands of hip prosthesis. The second phase was aimed at calculating, on the basis of the results of cost–utility analysis, a tender score for each device (defined according to standard tendering equations and adapted to a 0–100 scale). This allowed us to determine the ranking of each device in the simulated tender. Results We identified a single study as the source of information for our analysis. Nine device brands (cemented, cementless, or hybrid) were evaluated. The cemented prosthesis Exeter V40/Elite Plus Ogee, the cementless device Taperloc/Exceed, and the hybrid device Exeter V40/Trident had the highest NMB (£152 877, £156 356, and £156 210, respectively) and the best value-based tender score. Conclusions The incorporation of value-based criteria in the procurement process can contribute to optimising the value for money for THA devices. According to the approach described herein, the acquisition of these devices does not necessarily converge on the product with the lowest cost; in fact, more costly devices should be preferred when their increased cost is offset by the monetary value of the increased clinical benefit. PMID:29259062

  15. Albumin as marker for susceptibility to metal ions in metal-on-metal hip prosthesis patients.

    PubMed

    Facchin, F; Catalani, S; Bianconi, E; Pasquale, D De; Stea, S; Toni, A; Canaider, S; Beraudi, A

    2017-04-01

    Metal-on-metal (MoM) hip prostheses are known to release chromium and cobalt (Co), which negatively affect the health status, leading to prosthesis explant. Albumin (ALB) is the main serum protein-binding divalent transition metals. Its binding capacity can be affected by gene mutations or modification of the protein N-terminal region, giving the ischaemia-modified albumin (IMA). This study evaluated ALB, at gene and protein level, as marker of individual susceptibility to Co in MoM patients, to understand whether it could be responsible for the different management of this ion. Co was measured in whole blood, serum and urine of 40 MoM patients. A mutational screening of ALB was performed to detect links between mutations and metal binding. Finally, serum concentration of total ALB and IMA were measured. Serum total ALB concentration was in the normal range for all patients. None of the subjects presented mutations in the investigated gene. Whole blood, serum and urine Co did not correlate with serum total ALB or IMA, although IMA was above the normal limit in most subjects. The individual susceptibility is very important for patients' health status. Despite the limited results of this study, we provide indications on possible future investigations on the toxicological response to Co.

  16. Cerclage wires or cables for the management of intraoperative fracture associated with a cementless, tapered femoral prosthesis: results at 2 to 16 years.

    PubMed

    Berend, Keith R; Lombardi, Adolph V; Mallory, Thomas H; Chonko, Douglas J; Dodds, Kathleen L; Adams, Joanne B

    2004-10-01

    Initial stability is critical for fixation and survival of cementless total hip arthroplasty. Occasionally, a split of the calcar occurs intraoperatively. A review of 1,320 primary total hip arthroplasties with 2-year follow-up, performed between August 1985 and February 2001 using the Mallory-Head Porous tapered femoral component, revealed 58 hips in 55 patients with an intraoperative calcar fracture managed with single or multiple cerclage wires or cables and immediate full weight bearing. At 7.5 years average follow-up (range, 2-16 years), there were no revisions of the femoral component, radiographic failures, or patients with severe thigh pain, for a stem survival rate of 100%. Average Harris hip score improvement was 33.8 points. Fracture of the proximal femur occurs in approximately 4% of primary THAs using the Mallory-Head Porous femoral component. When managed intraoperatively with cerclage wire or cable, the mid- to long-term results appear unaffected with 100% femoral component survival at up to 16 years.

  17. Simultaneous Bilateral Femur Neck Fracture in A Young Adult with Chronic Renal Failure- A Case Report and Review of Literature.

    PubMed

    V, Sathyanarayana; Patel, Maulik Tulsibhai; S, Raghavan; D, Naresh

    2015-01-01

    Pathological bilateral femoral neck fracture due to renal osteodystrophy is rare. This is a report of a chronic renal failure patient who had sustained bilateral intra-capsular displaced fracture neck of femur following an episode of convulsion and the difficulties encountered in early diagnosis and treatment. The pathophysiology of renal osteodystrophy and the treatment of hip fractures in patients with renal failure are also discussed. A 23 years old male patient admitted with h/o dysuria, pyuria and loss of appetite since 3 months. He was a known case of chronic renal failure and reflux nephropathy. On investigating, patient's renal parameters were high and he was started with haemodialysis. The next day patient had c/o bilateral hip pain and inability to move bilateral lower limbs following an episode of seizure. Radiograph of pelvis showed vertical sub capital fractures of bilateral neck of femur. In this patient, considering his age, general condition & prognosis, an elective surgery in the form of bilateral uncemented modular bipolar hemiarthroplasty was done. Overall risk of hip fracture among patients with chronic renal failure is considerably higher than in the general population, independent of age and gender. Simultaneous spontaneous bilateral fractures of the femoral neck are rare and a delayed diagnosis is usual. The study of etiological factors of these fractures is essential to guide us in choosing the treatment of choice. Obviously patient's age, life expectancy as well as renal co morbidity has an influence over deciding treatment and outcome.

  18. Friction in hip prostheses.

    PubMed

    Hall, R M; Unsworth, A

    1997-08-01

    Although the reduction of frictional torques was the driving force behind the design of the Charnley prosthesis, later concerns about wear and subsequent loosening of this and other hip replacements have dominated debate within the bioengineering community. To stimulate discussion on the role of friction in loosening, a review of the frictional characteristics of different prostheses was undertaken. The use of simple laboratory screening-type machines in the frictional assessment of different material combinations is discussed together with experiments performed on single axis simulators using both conventional and experimental prostheses. In particular, recent developments in the use of soft layer components are highlighted. Further, the possible link between excessively high frictional torques and loosening is discussed in the light of current results obtained from explanted prostheses.

  19. Tribology of total hip arthroplasty prostheses

    PubMed Central

    Rieker, Claude B.

    2016-01-01

    Articulating components should minimise the generation of wear particles in order to optimize long-term survival of the prosthesis. A good understanding of tribological properties helps the orthopaedic surgeon to choose the most suitable bearing for each individual patient. Conventional and highly cross-linked polyethylene articulating either with metal or ceramic, ceramic-on-ceramic and metal-on-metal are the most commonly used bearing combinations. All combinations of bearing surface have their advantages and disadvantages. An appraisal of the individual patient’s objectives should be part of the assessment of the best bearing surface. Cite this article: Rieker CB. Tribology of total hip arthroplasty prostheses: what an orthopaedic surgeon should know. EFORT Open Rev 2016;1:52-57. DOI: 10.1302/2058-5241.1.000004. PMID:28461928

  20. Comparison of Hydroxyapatite-coated stems in total hip arthroplasty after a minimum 10-years follow-up.

    PubMed

    Gallo, J; Landor, I; Cechová, I; Jahoda, D

    2008-10-01

    PURPOSE OF THE STUDY Hydroxypatite coating (HAC) was introduced into total hip arthroplasty (THA) practice to improve the fixation interface between bone and prosthesis. To test this assumption however, long-term follow-up investigations are needed. In this study, we present data for two consecutive series of THA stems with HAC and a minimum ten-year follow-up. MATERIAL Overall, 249 patients (271 hips) were included in the study, of these 122 (135 hips) had Walter hip arthroplasty (WHA group) with a two-layered TiO2/HAC at the proximal part of the stem and 127 (136 hips) had ABG I prostheses (ABG I group) with a single-layered HAC at the proximal part of the stem. Mean length of follow-up was 11.4 years (0.8-13) and 9.8 years (4-12) in WHA and ABG I groups, respectively. Mean age at the time of surgery was 62 years (23-79) and 47 years (21-65) in WHA and ABG I groups, respectively. METHODS Probabilities of implant survival were estimated using the Kaplan-Meier method. Radiographic data were included to construct the worst-case scenario. Differences in survival curves were evaluated by Gehan's Wilcoxon test. Harris hip score was used to compare preoperative status with that of final follow-up. RESULTS The overall survival of WHA was significantly better than the ABG I (0.85 versus 0.66; p < 0.05). The main reason for a high revision rate in ABG I was periprosthetic osteolysis followed by aseptic loosening. With regard to stems, the survivorship curve for the Walter stem was significantly better than for the ABG I stem even when radiographic results were included (p = 0.0002). In the WHA group, two stems (1.5%) were revised due to sepsis, in contrast to thirty-one stems (23.5%) revised in the ABG I group due to osteolysis and aseptic loosening (p < 0.05). Significant improvement was achieved in both groups under study in terms of Harris hip score. DISCUSSION Data presented here appear surprising at first glance because the differences between the stems under study are only minor. The failure in ABG I was most probably caused by poor polyethylene quality and poor locking mechanism of polyethylene liner in the metallic shell. In addition, HAC used in ABG I prosthesis was not able to prevent the development of polyethylene disease stimulated by high wear rate. CONCLUSION This study revealed excellent survivorship for WHA stems after a minimum ten-year survival and significantly poorer survivorship for the ABG I stems.This may be explained at least particularly by combined two-layered HAC used in WHA stems which provide simultaneously endurable bone interlocking and effective barrier against expansion of polyethylene disease.

  1. Comparison of techniques for correction of magnification of pelvic X-rays for hip surgery planning.

    PubMed

    The, Bertram; Kootstra, Johan W J; Hosman, Anton H; Verdonschot, Nico; Gerritsma, Carina L E; Diercks, Ron L

    2007-12-01

    The aim of this study was to develop an accurate method for correction of magnification of pelvic x-rays to enhance accuracy of hip surgery planning. All investigated methods aim at estimating the anteroposterior location of the hip joint in supine position to correctly position a reference object for correction of magnification. An existing method-which is currently being used in clinical practice in our clinics-is based on estimating the position of the hip joint by palpation of the greater trochanter. It is only moderately accurate and difficult to execute reliably in clinical practice. To develop a new method, 99 patients who already had a hip implant in situ were included; this enabled determining the true location of the hip joint deducted from the magnification of the prosthesis. Physical examination was used to obtain predictor variables possibly associated with the height of the hip joint. This included a simple dynamic hip joint examination to estimate the position of the center of rotation. Prediction equations were then constructed using regression analysis. The performance of these prediction equations was compared with the performance of the existing protocol. The mean absolute error in predicting the height of the hip joint center using the old method was 20 mm (range -79 mm to +46 mm). This was 11 mm for the new method (-32 mm to +39 mm). The prediction equation is: height (mm) = 34 + 1/2 abdominal circumference (cm). The newly developed prediction equation is a superior method for predicting the height of the hip joint center for correction of magnification of pelvic x-rays. We recommend its implementation in the departments of radiology and orthopedic surgery.

  2. An experimental animal model of aseptic loosening of hip prostheses in sheep to study early biochemical changes at the interface membrane

    PubMed Central

    El-Warrak, Alexander O; Olmstead, Marvin; Schneider, Rebecca; Meinel, Lorenz; Bettschart-Wolfisberger, Regula; Akens, Margarete K; Auer, Joerg; von Rechenberg, Brigitte

    2004-01-01

    Background Aseptic loosening of hip prosthesis as it occurs in clinical cases in human patients was attributed to wear particles of the implants, the response of the tissue dominated by macrophages and the production of inflammatory mediators and matrix degrading enzymes; however, the cascade of events initiating the process and their interaction regarding the time course is still open and discussed controversially. Therefore, the goal of this study was to establish an experimental animal model in sheep allowing to follow the cascade of early mechanical and biochemical events within the interface membrane and study the sequence of how they contribute to the pathological bone resorption necessary for aseptic loosening of the implant. Methods A cemented modular system (Biomedtrix) was used as a hip replacement in 24 adult Swiss Alpine sheep, with one group receiving a complete cement mantle as controls (n = 12), and the other group a cement mantle with a standardized, lateral, primary defect in the cement mantle (n = 12). Animals were followed over time for 2 and 8.5 months (n = 6 each). After sacrifice, samples from the interface membranes were harvested from five different regions of the femur and joint capsule. Explant cell cultures were performed and supernatant of cultures were tested and assayed for nitric oxide, prostaglandin E2, caseinolytic and collagenolytic activity. RNA extraction and quantification were performed for inducible nitric oxide synthase, cyclooxygenase-2, interleukin 1, and interleukin 6. Overall differences between groups and time periods and interactions thereof were calculated using a factorial analysis of variance (ANOVA). Results The development of an interface membrane was noticed in both groups at both time points. However, in the controls the interface membrane regressed in thickness and biological activity, while both variables increased in the experimental group with the primary cement mantle defect over time. Nitric oxide (NO) and PGE2 concentrations were higher in the 8.5 months group (P < 0.0001) compared to the 2 months group with a tendency for the unstable group to have higher concentrations. The same was true for collagenolytic activity (P = 0.05), but not for caseinolytic activity that decreased over time (P < 0.0001). Conclusion In this study, a primary cement mantle defect of the femoral shaft elicited biomechanical instability and biochemical changes over time in an experimental animal study in sheep, that resembled the changes described at the bone cement-interface in aseptic loosening of total hip prosthesis in humans. The early biochemical changes may well explain the pathologic bone resorption and formation of an interface membrane as is observed in clinical cases. This animal model may aid in future studies aiming at prevention of aseptic loosening of hip prosthesis and reflect some aspects of the pathogenesis involved. PMID:15113432

  3. Short-term survival of the trabecular metal cup is similar to that of standard cups used in acetabular revision surgery.

    PubMed

    Mohaddes, Maziar; Rolfson, Ola; Kärrholm, Johan

    2015-02-01

    The use of trabecular metal (TM) cups in revision surgery has increased worldwide during the last decade. Since the introduction of the TM cup in Sweden in 2006, this design has gradually replaced other uncemented designs used in Sweden. According to data from the Swedish Hip Arthroplasty Register (SHAR) in 2012, one-third of all uncemented first-time cup revisions were performed using a TM cup. We compared the risk of reoperation and re-revision for TM cups and the 2 other most frequently used cup designs in acetabular revisions reported to the SHAR. The hypothesis was that the performance of TM cups is as good as that of established designs in the short term. The study population consisted of 2,384 patients who underwent 2,460 revisions during the period 2006 through 2012. The most commonly used cup designs were the press-fit porous-coated cup (n = 870), the trabecular metal cup (n = 805), and the cemented all-polyethylene cup (n = 785). 54% of the patients were female, and the median age at index revision was 72 (19-95) years. Reoperation was defined as a second surgical intervention, and re-revision-meaning exchange or removal of the cup-was used as endpoint. The mean follow-up time was 3.3 (0-7) years. There were 215 reoperations, 132 of which were re-revisions. The unadjusted and adjusted risk of reoperation or re-revision was not significantly different for the TM cup and the other 2 cup designs. Our data support continued use of TM cups in acetabular revisions. Further follow-up is necessary to determine whether trabecular metal cups can reduce the re-revision rate in the long term, compared to the less costly porous press-fit and cemented designs.

  4. Measurement of small lesions near metallic implants with mega-voltage cone beam CT

    NASA Astrophysics Data System (ADS)

    Grigorescu, Violeta; Prevrhal, Sven; Pouliot, Jean

    2008-03-01

    Metallic objects severely limit diagnostic CT imaging because of their high X-ray attenuation in the diagnostic energy range. In contrast, radiation therapy linear accelerators now offer CT imaging with X-ray energies in the megavolt range, where the attenuation coefficients of metals are significantly lower. We hypothesized that Mega electron-Voltage Cone-Beam CT (MVCT) implemented on a radiation therapy linear accelerator can detect and quantify small features in the vicinity of metallic implants with accuracy comparable to clinical Kilo electron-Voltage CT (KVCT) for imaging. Our test application was detection of osteolytic lesions formed near the metallic stem of a hip prosthesis, a condition of severe concern in hip replacement surgery. Both MVCT and KVCT were used to image a phantom containing simulated osteolytic bone lesions centered around a Chrome-Cobalt hip prosthesis stem with hemispherical lesions with sizes and densities ranging from 0.5 to 4 mm radius and 0 to 500 mg•cm -3, respectively. Images for both modalities were visually graded to establish lower limits of lesion visibility as a function of their size. Lesion volumes and mean density were determined and compared to reference values. Volume determination errors were reduced from 34%, on KVCT, to 20% for all lesions on MVCT, and density determination errors were reduced from 71% on KVCT to 10% on MVCT. Localization and quantification of lesions was improved with MVCT imaging. MVCT offers a viable alternative to clinical CT in cases where accurate 3D imaging of small features near metallic hardware is critical. These results need to be extended to other metallic objects of different composition and geometry.

  5. Operating theatre ventilation systems and microbial air contamination in total joint replacement surgery: results of the GISIO-ISChIA study.

    PubMed

    Agodi, A; Auxilia, F; Barchitta, M; Cristina, M L; D'Alessandro, D; Mura, I; Nobile, M; Pasquarella, C

    2015-07-01

    Recent studies have shown a higher rate of surgical site infections in hip prosthesis implantation using unidirectional airflow ventilation compared with turbulent ventilation. However, these studies did not measure the air microbial quality of operating theatres (OTs), and assumed it to be compliant with the recommended standards for this ventilation technique. To evaluate airborne microbial contamination in OTs during hip and knee replacement surgery, and compare the findings with values recommended for joint replacement surgery. Air samplings were performed in 28 OTs supplied with unidirectional, turbulent and mixed airflow ventilation. Samples were collected using passive sampling to determine the index of microbial air contamination (IMA). Active sampling was also performed in some of the OTs. The average number of people in the OT and the number of door openings during the sampling period were recorded. In total, 1228 elective prosthesis procedures (60.1% hip and 39.9% knee) were included in this study. Of passive samplings performed during surgical activity in unidirectional airflow ventilation OTs (U-OTs) and mixed airflow OTs (M-OTs), 58.9% and 87.6% had IMA values >2, respectively. Of samplings performed during surgical activity in turbulent airflow OTs (T-OTs) and in turbulent airflow OTs with the surgical team wearing Steri-Shield Turbo Helmets (TH-OTs), 8.6% and 60% had IMA values ≤ 2, respectively. Positive correlation was found between IMA values and the number of people in the OT and the number of door openings (P < 0.001). In addition, correlation was found between active and passive sampling (P < 0.001). These findings challenge the belief that unidirectional systems always provide acceptable airborne bacterial counts. Copyright © 2015 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  6. Reproducibility of femoral offset following short stem and straight stem total hip arthroplasty.

    PubMed

    von Roth, Philipp; Perka, Carsten; Mayr, Hermann O; Preininger, Bernd; Ziebula, Friedrich; Matziolis, Georg; Hube, Robert

    2014-07-01

    Bone stock-preserving short stem prostheses have gained importance in total hip arthroplasty (THA) with the use of minimally invasive surgical procedures. Because of their metaphyseal fixation and their dependency on the calcar radius, it is unknown whether the femoral offset can be reproduced with the same accuracy following short stem vs standard stem THA. This study clarifies whether it is possible to restore the femoral offset using a short stem prosthesis (Fitmore; Zimmer, Warsaw, Indiana) compared with a conventional straight stem prosthesis (CLS; Zimmer) following minimally invasive implantation using an anterolateral approach. In a prospective, randomized, double-blinded study, 80 patients underwent THA using a short stem (SS group; n=40) or CLS implant (control group; n=40). Follow-up examinations were conducted 6 weeks postoperatively. Radiological and functional outcomes were measured. Subjective assessment of quality of life was evaluated using the Harris Hip Score (HHS), the Short Form 36-item health survey (SF-36), and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Pre- and postoperative comparison of the groups' change in offset showed no significant differences (SS group difference from pre- to postoperative, 6.1±6.5 mm; control group difference from pre- to postoperative, 6.5±7.1 mm; P=.93). Group comparison after 6 weeks revealed no significant differences in HHS, SF-36, or WOMAC. Based on these data, an equivalent reproducibility of the femoral offset was demonstrated following short stem and straight stem THA using a minimally invasive anterolateral approach. If the long-term results of short stems show a comparable survival, they represent a sensible alternative to standard stems. Copyright 2014, SLACK Incorporated.

  7. Staphylococcus aureus infections following knee and hip prosthesis insertion procedures.

    PubMed

    Arduino, Jean Marie; Kaye, Keith S; Reed, Shelby D; Peter, Senaka A; Sexton, Daniel J; Chen, Luke F; Hardy, N Chantelle; Tong, Steven Yc; Smugar, Steven S; Fowler, Vance G; Anderson, Deverick J

    2015-01-01

    Staphylococcus aureus is the most common and most important pathogen following knee and hip arthroplasty procedures. Understanding the epidemiology of invasive S. aureus infections is important to quantify this serious complication. This nested retrospective cohort analysis included adult patients who had undergone insertion of knee or hip prostheses with clean or clean-contaminated wound class at 11 hospitals between 2003-2006. Invasive S. aureus infections, non-superficial incisional surgical site infections (SSIs) and blood stream infections (BSIs), were prospectively identified following each procedure. Prevalence rates, per 100 procedures, were estimated. 13,719 prosthetic knee (62%) and hip (38%) insertion procedures were performed. Of 92 invasive S. aureus infections identified, SSIs were more common (80%) than SSI and BSI (10%) or BSI alone (10%). The rate of invasive S. aureus infection/100 procedures was 0.57 [95% CI: 0.43-0.73] for knee insertion and 0.83 [95% CI: 0.61-1.08] for hip insertion. More than half (53%) were methicillin-resistant. Median time-to-onset of infection was 34 and 26 days for knee and hip insertion, respectively. Infection was associated with higher National Healthcare Safety Network risk index (p ≤ 0.0001). Post-operative invasive S. aureus infections were rare, but difficult-to-treat methicillin-resistant infections were relatively common. Optimizing preventative efforts may greatly reduce the healthcare burden associated with S. aureus infections.

  8. Treatment Challenges of Prosthetic Hip Infection with Associated Iliacus Muscle Abscess: Report of 5 Cases and Literature Review.

    PubMed

    Lawrenz, Joshua M; Mesko, Nathan W; Higuera, Carlos A; Molloy, Robert M; Simpfendorfer, Claus; Babic, Maja

    2017-01-01

    Prosthetic joint infection is an unfortunate though well-recognized complication of total joint arthroplasty. An iliacus and/or iliopsoas muscle abscess is a rarely documented presentation of hip prosthetic joint infection. It is thought an unrecognized retroperitoneal nidus of infection can be a source of continual seeding of the prosthetic hip joint, prolonging attempts to eradicate infection despite aggressive debridement and explant attempts. The current study presents five cases demonstrating this clinical scenario, and discusses various treatment challenges. In each case we report the patient's clinical history, pertinent imaging, management and outcome. Diagnosis of the iliacus muscle abscess was made using computed tomography imaging. In brief, the mean number of total drainage procedures (open and percutaneous) per patient was 4.2, and outcomes consisted of one patient with a hip girdlestone, two patients with delayed revisions, and two patients with retained prosthesis. All patients ended with functional pain and on oral antibiotic suppression with an average follow up of 18 months. This article highlights an iliacus muscle abscess as an unrecognized source of infection to a prosthetic hip. It demonstrates resilience to standard treatment protocols for prosthetic hip infection, and is associated with poor patient outcomes. Aggressive surgical debridement appears to remain critical to treatment success, and early retroperitoneal debridement of the abscess should be considered.

  9. Posterosuperior Placement of a Standard-Sized Cup at the True Acetabulum in Acetabular Reconstruction of Developmental Dysplasia of the Hip With High Dislocation.

    PubMed

    Xu, Jiawei; Xu, Chen; Mao, Yuanqing; Zhang, Jincheng; Li, Huiwu; Zhu, Zhenan

    2016-06-01

    We sought to evaluate posterosuperior placement of the acetabular component at the true acetabulum during acetabular reconstruction in patients with Crowe type-IV developmental dysplasia of the hip. Using pelvic computed tomography and image processing, we developed a two-dimensional mapping technique to demonstrate the distribution of preoperative three-dimensional cup coverage at the true acetabulum, determined the postoperative location of the acetabular cup, and calculated postoperative three-dimensional coverage for 16 Crowe type-IV dysplastic hips in 14 patients with a mean age of 52 years (33-78 years) who underwent total hip arthroplasty. Mean follow-up was 6.3 years (5.5-7.3 years). On preoperative mapping, the maximum three-dimensional coverage using a 44-mm cup was 87.31% (77.36%-98.14%). Mapping enabled the successful replacement of 16 hips using a mean cup size of 44.13 mm (42-46 mm) with posterosuperior placement of the cup. Early weight-bearing and no prosthesis revision or loosening during follow-up were achieved in all patients. The postoperative two-dimensional coverage on anteroposterior radiographs and three-dimensional coverage were 96.15% (89.49%-100%) and 83.42% (71.81%-98.50%), respectively. This technique may improve long-term implant survival in patients with Crowe-IV developmental dysplasia of the hip undergoing total hip arthroplasty by allowing the use of durable bearings, increasing host bone coverage, ensuring initial stability, and restoring the normal hip center. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Canadian academic experience with metal-on-metal hip resurfacing.

    PubMed

    O'Neill, Michelle; Beaule, Paul E; Bin Nasser, Ahmad; Garbuz, Donald; Lavigne, Martin; Duncan, Clive; Kim, Paul R; Schemitsch, Emil

    2009-01-01

    The current depth and breadth of experience in hip resurfacing in Canadian academic centers is not well known. This study endeavors to increase awareness of the prevalence of programs and current experience in a select number of representative teaching centers by examining the learning curve of high-volume surgeons. A questionnaire was sent to all academic centers in Canada to identify the volume of hip resurfacing, surgical approach, and type of prosthesis. In addition, five surgeons, not fellowship-trained in hip resurfacing, were selected for a detailed review of their first 50 cases, including survey of patient demographics, surgical approach, radiographic evaluation, complications, and revision. Eleven of 14 academic centers are currently performing hip resurfacing. All of these centers had performed more than 50 cases, with 10 of 11 of them having more than one surgeon performing the procedure. The posterior approach was found to be the most commonly utilized in surgeries. The overall revision rate was 3.2% at a mean time of 2 years, with femoral neck fracture (1.6%) being the most common cause for failure. The failure rate was comparable to other centers of expertise and lower than previously published multicenter trials. All surgeons reviewed were in specialized arthroplasty practices, which may contribute to the relatively low complication rates reported.

  11. Integral multidisciplinary approach in a patient with chronic complete spinal cord injury and hip disarticulation.

    PubMed

    Quinzaños-Fresnedo, J; Rodríguez-Reyes, G; Mendoza-Cosío, C; Pérez-Zavala, R; Márquez-Guitérrez, E A; Hernández-Sandoval, S

    2015-01-01

    Case report. To highlight the importance of the integral multidisciplinary management of a patient with complete chronic spinal cord injury and hip disarticulation secondary to pressure ulcers (PU). Mexico City. The case of a 40-year-old male violinist with a spinal cord injury, American Spinal Injury Association Impairment Scale A and neurological level T4, is reported. The patient initiated with bilateral ischiatic, left trochanteric and sacral PU. The ulcers were complicated with infection with sluggish evolution. Thus, it was decided a multidisciplinary management by means of left hip disarticulation and elaboration of a cosmetic prosthesis and the manufacture of a viscous elastic foam cushion for the prevention of new PU. The patient was quickly included in his professional and social activities. This study proves that multidisciplinary management of patients with spinal cord injury with complications such as the presence of PU that are resistant to noninvasive treatment can be the solution for the patient's reintegration into their normal life with adequate quality of life.

  12. Cobalt toxicity after revision total hip replacement due to fracture of a ceramic head.

    PubMed

    Pelayo-de Tomás, J M; Novoa-Parra, C; Gómez-Barbero, P

    Symptomatic cobalt toxicity from a failed total hip replacement is a rare, but devastating complication. Potential clinical findings include cardiomyopathy, hypothyroidism, skin rash, visual and hearing impairment, polycythaemia, weakness, fatigue, cognitive impairment, and neuropathy. The case is presented of a 74year-old man in whom, after a ceramic-ceramic replacement and two episodes of prosthetic dislocation, it was decided to replace it with a polyethylene-metal total hip arthroplasty (THA). At 6months after the revision he developed symptoms of cobalt toxicity, confirmed by analytical determination (serum cobalt level=651.2μg/L). After removal of the prosthesis, the levels of chromium and cobalt in blood and urine returned to normal, with the patient currently being asymptomatic. It is recommended to use a new ceramic on ceramic bearing at revision, in order to minimise the risk of wear-related cobalt toxicity following breakage of ceramic components. Copyright © 2016 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

  13. Outcomes of a metal-on-metal total hip replacement system.

    PubMed

    Matharu, G S; Theivendran, K; Pynsent, P B; Jeys, L; Pearson, A M; Dunlop, D J

    2014-10-01

    High short-term failure rates have been reported for a variety of metal-on-metal (MoM) total hip replacements (THRs) owing to adverse reactions to metal debris (ARMD). This has led to the withdrawal of certain poorly performing THRs. This study analysed the outcomes of a MoM THR system. Between 2004 and 2010, 578 uncemented MoM THRs (511 patients, mean age: 60.0 years) were implanted at one specialist centre. The THR system used consisted of the Corail(®) stem, Pinnacle(®) cup, Ultamet(®) liner and Articul/eze(®) femoral head (all DePuy, Leeds, UK). All patients were recalled for clinical review with imaging performed as necessary. The mean follow-up duration was 5.0 years (range: 1.0-9.1 years). Overall, 39 hips (6.7%) in 38 patients (all 36 mm femoral head size) underwent revision at a mean time of 3.5 years (range: 0.01-8.3 years) from the index THR with 30 revisions (77%) performed in women. The cumulative eight-year survival rate for all THRs was 88.9% (95% confidence interval [CI]: 78.5-93.4%), with no difference (p=0.053) between male (95.2%, 95% CI: 84.2-98.7%) and female patients (85.3%, 95% CI: 70.2-92.1%) at eight years. Seventeen revisions (44%) were performed for ARMD. There was no significant difference in absolute postoperative Oxford hip scores between men and women (p=0.608). The mean acetabular inclination in unrevised THRs was 44.0°. Forty-seven non-revised THRs (8.7%) had blood metal ion concentrations above recommended thresholds (seven had periprosthetic effusions). Although this MoM THR system has not failed as dramatically as other similar designs, we recommend against continued use and advise regular clinical surveillance to identify ARMD early.

  14. Tribology of total hip arthroplasty prostheses: What an orthopaedic surgeon should know.

    PubMed

    Rieker, Claude B

    2016-02-01

    Articulating components should minimise the generation of wear particles in order to optimize long-term survival of the prosthesis.A good understanding of tribological properties helps the orthopaedic surgeon to choose the most suitable bearing for each individual patient.Conventional and highly cross-linked polyethylene articulating either with metal or ceramic, ceramic-on-ceramic and metal-on-metal are the most commonly used bearing combinations.All combinations of bearing surface have their advantages and disadvantages. An appraisal of the individual patient's objectives should be part of the assessment of the best bearing surface. Cite this article: Rieker CB. Tribology of total hip arthroplasty prostheses: what an orthopaedic surgeon should know. EFORT Open Rev 2016;1:52-57. DOI: 10.1302/2058-5241.1.000004.

  15. [Avascular necrosis of the femoral head].

    PubMed

    Porubský, Peter; Trč, Tomáš; Havlas, Vojtěch; Smetana, Pavel

    Avascular necrosis of the femoral head in adults is not common, but not too rare diseases. In orthopedic practice, it is one of the diseases that are causing implantation of hip replacement at a relatively early age. In the early detection and initiation of therapy can delay the implantation of prosthesis for several years, which is certainly more convenient for the patient and beneficial. This article is intended to acquaint the reader with the basic diagnostic procedures and therapy.

  16. Designing an Optimized Novel Femoral Stem

    PubMed Central

    Babaniamansour, Parto; Ebrahimian-Hosseinabadi, Mehdi; Zargar-Kharazi, Anousheh

    2017-01-01

    Background: After total hip arthroplasty, there would be some problems for the patients. Implant loosening is one of the significant problems which results in thigh pain and even revision surgery. Difference between Young's modulus of bone-metal is the cause of stress shielding, atrophy, and subsequent implant loosening. Materials and Methods: In this paper, femoral stem stiffness is reduced by novel biomechanical and biomaterial design which includes using proper design parameters, coating it with porous surface, and modeling the sketch by the software. Parametric design of femoral stem is done on the basis of clinical reports. Results: Optimized model for femoral stem is proposed. Curved tapered stem with trapezoidal cross-section and particular neck and offset is designed. Fully porous surface is suggested. Moreover, Designed femoral stem analysis showed the Ti6Al4V stem which is covered with layer of 1.5 mm in thickness and 50% of porosity is as stiff as 77 GPa that is 30% less than the stem without any porosity. Porous surface of designed stem makes it fix biologically; thus, prosthesis loosening probability decreases. Conclusion: By optimizing femoral stem geometry (size and shape) and also making a porous surface, which had an intermediate stiffness of bone and implant, a more efficient hip joint prosthesis with more durability fixation was achieved due to better stress transmission from implant to the bone. PMID:28840118

  17. THE BIOMECHANICAL RESPONSE OF PERSONS WITH TRANSFEMORAL AMPUTATION TO VARIATIONS IN PROSTHETIC KNEE ALIGNMENT DURING LEVEL WALKING

    PubMed Central

    Koehler-McNicholas, Sara R.; Lipschutz, Robert D.; Gard, Steven A.

    2017-01-01

    Prosthetic alignment is an important factor in the overall fit and performance of a lower-limb prosthesis. However, the association between prosthetic alignment and control strategies used by persons with transfemoral amputation to coordinate the movement of a passive prosthetic knee is poorly understood. This study investigated the biomechanical response of persons with transfemoral amputation to systematic perturbations in knee joint alignment during a level walking task. Quantitative gait data were collected for three alignment conditions: bench alignment, 2 cm anterior knee translation (ANT), and 2 cm posterior knee translation (POST). In response to a destabilizing alignment perturbation (ANT), subjects significantly increased their early-stance hip extension moment, confirming that persons with transfemoral amputation rely on a hip extensor strategy to maintain knee joint stability. However, subjects also decreased the rate at which they loaded their prosthesis, decreased their step length, increased their trunk flexion, and maintained their limb in a more vertical posture at the time of opposite toe off. Collectively, these results suggest that persons with transfemoral amputation rely on a combination of strategies to coordinate stance-phase knee flexion. Further, no significant changes were observed in response to the POST condition, suggesting that a bias toward posterior alignment may have fewer implications in terms of stance-phase, knee-joint control. PMID:28355034

  18. [Tumor prostheses : Important in modern revision arthroplasty].

    PubMed

    Hillmann, A; Ipach, I

    2015-05-01

    Due to demographic aging, an increasing number of revision arthroplasty procedures is expected during upcoming years. While the use of a megaprosthesis for bone reconstruction after tumor resection is gold standard, this type of prosthesis still meets with reservation in the field of revision arthroplasty because of numerous risk factors. The purpose of this article is to present the importance of modular megaprostheses in revision arthroplasty, taking into consideration the risks of periprosthetic infection, aseptic loosening, material failure, and hip dislocation. Because of improvements in the field of megaprostheses during the last 30 years, the risks after implantation of this type of prosthesis have significantly decreased. The risk of periprosthetic infection has been reduced about 1/3 by the use of silver surface coating. Improvements in stem design, cement technique, and the additional use of locking screws have minimized the risk of aseptic loosening. Improvements in material composition have reduced the risk of material failure. The risk of hip dislocation could also be minimized by careful tissue preparation and appropriate suture technique. There is no need for the conservative use of megaprostheses in revision arthroplasty. There are many benefits in the use of megaprostheses in multimorbid patients (i.e., reduced operating time, the possibility of early full weight bearing, and a reduced risk of periprosthetic infection by the use of silver surface coating) instead of complex bone reconstruction during revision arthroplasty.

  19. Squat exercise to estimate knee megaprosthesis rehabilitation: a pilot study

    PubMed Central

    Lovecchio, Nicola; Zago, Matteo; Sciumè, Luciana; Lopresti, Maurizio; Sforza, Chiarella

    2015-01-01

    [Purpose] This study evaluated a specific rehabilitation protocol using a half squat after total knee reconstruction with distal femur megaprosthesis and tibial allograft-prosthesis composite. [Subject and Methods] Squat execution was recorded by a three-dimensional system before and after a specific rehabilitation program on a 28-year-old patient. Squat duration, body center of mass trajectory, and vertical range of motion were determined. Step width and joint angles and symmetry (hip flexion, extension, and rotation, knee flexion, and ankle dorsal and plantar flexion) were estimated. Knee and hip joint symmetry was computed using a bilateral cyclogram technique. [Results] After rehabilitation, the squat duration was longer (75%), step width was similar, and vertical displacement was higher. Hip flexion increased by over 20%, and ankle dorsiflexion diminished by 14%. The knee had the highest symmetry gain (4.1–3.4%). Angle-angle plot subtended areas decreased from 108° to 40°2 (hip) and from 204° to 85°2 (knee), showing improvement in movement symmetry. [Conclusion] We concluded that the squat is an effective multifactorial exercise to estimate rehabilitation outcomes after megaprosthesis, also considering that compressive and shear forces are minimal up to 60–70° of knee flexion. PMID:26311992

  20. First insight on the impact of an osteoblastic layer on the bio-tribocorrosion performance of Ti6Al4V hip implants.

    PubMed

    Runa, M J; Mathew, M T; Fernandes, M H; Rocha, L A

    2015-01-01

    In uncemented Ti6Al4V hip implants, the bone-stem interface is subjected to cyclic loading motion driven by the daily activities of the patients, which may lead to the complete failure of the implant in the long term. It may also compromise the proliferation and differentiation processes of osteoblastic cells (bone-forming cells). The main objective of this work is to approach for the first time the role of these organic materials on the bio-tribocorrosion mechanisms of cultured Ti6Al4V alloys. The colonized materials with MG63 osteoblastic-like cells were characterized through cell viability/proliferation and enzymatic activity. Tribocorrosion tests were performed under a reciprocating sliding configuration and low contact pressure. Electrochemical techniques were used to measure the corrosion kinetics of the system, under free potential conditions. All tests were performed at a controlled atmosphere. The morphology and topography of the wear scar were evaluated. The results showed that the presence of an osteoblastic cell layer on the implant surface significantly influences the tribocorrosion behavior of Ti6Al4V alloy. It was concluded that the cellular material was able to form an extra protective layer that inhibits further wear degradation of the alloy and decreases its corrosion tendency. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  1. Modern dual-mobility cup implanted with an uncemented stem: about 100 cases with 12-year follow-up.

    PubMed

    Philippot, Remi; Meucci, Jean Francois; Boyer, Bertrand; Farizon, Frederic

    2013-09-01

    We report the results of a 12-year follow-up retrospective series of 100 total hip arthroplasties using cementless, press-fit, dual-mobility acetabular cups. The aim of our study was to evaluate the clinical and radiographic results of this acetabular cup at last follow-up. This continuous and homogeneous series included 100 primary total hip arthroplasties performed during the year 2000. The THA combined a Corail® stem (Corail®, Depuy, Warsaw, IN) with a stainless steel Novae Sunfit® (Serf, Decines, France) acetabular cup. Fifteen patients died and 2 were lost to follow-up. Two cases of early dislocation were observed, and 3 cases of aseptic loosening of the acetabular component were reported. The mean stem subsidence was 0.71 mm, the mean craniopodal acetabular migration was 1.37 mm, and the mean medio-lateral acetabular migration was 1.52 mm. The 12-year survivorship is comparable to the data from the literature. The low dislocation rate at 12 years confirms the long-term, high stability of dual mobility, which should be recommended in primary THA for patients at risk for postoperative instability. The absence of true intraprosthetic dislocation events at 12-year follow-up provides evidence of the good quality of the latest generation of polyethylene liners and the necessity of combining thin-mirror, polished femoral necks with dual-mobility cups.

  2. Reconstruction of failed acetabular component in the presence of severe acetabular bone loss: a systematic review.

    PubMed

    Volpin, A; Konan, S; Biz, C; Tansey, R J; Haddad, F S

    2018-04-13

    Acetabular revision especially in the presence of severe bone loss is challenging. There is a paucity of literature critiquing contemporary techniques of revision acetabular reconstruction and their outcomes. The purpose of this study was to systematically review the literature and to report clinical outcomes and survival of contemporary acetabular revision arthroplasty techniques (tantalum metal shells, uncemented revision jumbo shells, reinforced cages and rings, oblong shells and custom-made triflange constructs). Full-text papers and those with an abstract in English published from January 2001 to January 2016 were identified through international databases. A total of 50 papers of level IV scientific evidence, comprising 2811 hips in total, fulfilled the inclusion criteria and were included. Overall, patients had improved outcomes irrespective of the technique of reconstruction as documented by postoperative hip scores. Our pooled analysis suggests that oblong cups components had a lower failure rate compared with other different materials considered in this review. Custom-made triflange cups had one of highest failure rates. However, this may reflect the complexity of revisions and severity of bone loss. The most common postoperative complication reported in all groups was dislocation. This review confirms successful acetabular reconstructions using diverse techniques depending on the type of bone loss and highlights key features and outcomes of different techniques. In particular, oblong cups and tantalum shells have successful survivorship.

  3. Radiostereometric analysis of hemiarthroplasties of the hip--a highly precise method for measurements of cartilage wear.

    PubMed

    Figved, W; Dahl, J; Snorrason, F; Frihagen, F; Röhrl, S; Madsen, J E; Nordsletten, L

    2012-01-01

    Cartilage wear is a feature of osteoarthritis and rheumatoid arthritis. Precise measurements of wear have been difficult. Cartilage wear caused by an artificial articulating joint surface is a well-known feature of hemiarthroplasties. The aim of this study was to demonstrate that radiostereometric analysis (RSA) may be used for three-dimensional measurements of cartilage wear in hemiarthroplasties of the hip. We performed a phantom model study to assess the feasibility of a subsequent clinical trial. We showed that the motion of the prosthetic head relative to the pelvis was not influenced by the orientation of the prosthetic head. Twenty-two patients were randomised to treatment with a cemented or an uncemented hemiarthroplasty for an acute femoral neck fracture. Migration of the prosthetic head into the acetabulum was measured using RSA. A mean migration of the prosthetic head into the acetabulum of 0.62 mm was found at 3 months [95% confidence interval (CI): 0.27-0.97] and a further migration of -0.07 mm at 12 months (95% CI: -0.16-0.32). There were no differences between the groups in prosthetic migration or functional outcome. Between three and 12 months, there was no detectable cartilage wear during the first postoperative year. Whether the migration during the first 3 months represents a period of bedding in due to a harder opposite surface remains to be shown. RSA may be used for measurement of cartilage wear in hemiarthroplasties of the hip. This study demonstrates a highly precise method for measurements of cartilage wear. Copyright © 2011 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  4. Outcome by mode of anaesthesia for hip fracture surgery. An observational audit of 65 535 patients in a national dataset.

    PubMed

    White, S M; Moppett, I K; Griffiths, R

    2014-03-01

    Large observational studies of accurate data can provide similar results to more arduous and expensive randomised controlled trials. In 2012, the National Hip Fracture Database extended its dataset to include 'type of anaesthesia' data fields. We analysed 65 535 patient record sets to determine differences in outcome. Type of anaesthesia was recorded in 59 191 (90%) patients. Omitting patients who received both general and spinal anaesthesia or in whom an uncertain type of anaesthesia was recorded, there was no significant difference in either cumulative five-day (2.8% vs 2.8%, p = 0.991) or 30-day (7.0% vs 7.5%, p = 0.053) mortality between 30 130 patients receiving general anaesthesia and 22 999 patients receiving spinal anaesthesia, even when 30-day mortality was adjusted for age and ASA physical status (p = 0.226). Mortality within 24 hours after surgery was significantly higher among patients receiving cemented compared with uncemented hemiarthroplasty (1.6% vs 1.2%, p = 0.030), suggesting excess early mortality related to bone cement implantation syndrome. If these data are accurate, then either there is no difference in 30-day mortality between general and spinal anaesthesia after hip fracture surgery per se, and therefore future research should focus on how to make both types of anaesthesia safer, or there is a difference, but mortality is not the correct outcome to measure after anaesthesia, and therefore future research should focus on differences between general and spinal anaesthesia. These could include more anaesthesia-sensitive outcomes, such as hypotension, pain, postoperative confusion, respiratory infection and mobilisation. © 2014 The Association of Anaesthetists of Great Britain and Ireland.

  5. Reconstruction with 3D-printed pelvic endoprostheses after resection of a pelvic tumour.

    PubMed

    Liang, H; Ji, T; Zhang, Y; Wang, Y; Guo, W

    2017-02-01

    The aims of this retrospective study were to report the feasibility of using 3D-printing technology for patients with a pelvic tumour who underwent reconstruction. A total of 35 patients underwent resection of a pelvic tumour and reconstruction using 3D-printed endoprostheses between September 2013 and December 2015. According to Enneking's classification of bone defects, there were three Type I lesions, 12 Type II+III lesions, five Type I+II lesions, two Type I+II+III lesions, ten type I+II+IV lesions and three type I+II+III+IV lesions. A total of three patients underwent reconstruction using an iliac prosthesis, 12 using a standard hemipelvic prosthesis and 20 using a screw-rod connected hemipelvic prosthesis. All patients had an en bloc resection. Margins were wide in 15 patients, marginal in 14 and intralesional in six. After a mean follow-up of 20.5 months (6 to 30), 25 patients survived without evidence of disease, five were alive with disease and five had died from metastatic disease. Complications included seven patients with delayed wound healing and two with a dislocation of the hip. None had a deep infection. For the 30 surviving patients, the mean Musculoskeletal Society 93 score was 22.7 (20 to 25) for patients with an iliac prosthesis, 19.8 (15 to 26) for those with a standard prosthesis, and 17.7 (9 to 25) for those with a screw-rod connected prosthesis. The application of 3D-printing technology can facilitate the precise matching and osseointegration between implants and the host bone. We found that the use of 3D-printed pelvic prostheses for reconstruction of the bony defect after resection of a pelvic tumour was safe, without additional complications, and gave good short-term functional results. Cite this article: Bone Joint J 2017;99-B:267-75. ©2017 The British Editorial Society of Bone & Joint Surgery.

  6. Revision total hip arthoplasty: factors associated with re-revision surgery.

    PubMed

    Khatod, Monti; Cafri, Guy; Inacio, Maria C S; Schepps, Alan L; Paxton, Elizabeth W; Bini, Stefano A

    2015-03-04

    The survivorship of implants after revision total hip arthroplasty and risk factors associated with re-revision are not well defined. We evaluated the re-revision rate with use of the institutional total joint replacement registry. The purpose of this study was to determine patient, implant, and surgeon factors associated with re-revision total hip arthroplasty. A retrospective cohort study was conducted. The total joint replacement registry was used to identify patients who had undergone revision total hip arthroplasty for aseptic reasons from April 1, 2001, to December 31, 2010. The end point of interest was re-revision total hip arthroplasty. Risk factors evaluated for re-revision total hip arthroplasty included: patient risk factors (age, sex, body mass index, race, and general health status), implant risk factors (fixation type, bearing surface, femoral head size, and component replacement), and surgeon risk factors (volume and experience). A multivariable Cox proportional hazards model was used. Six hundred and twenty-nine revision total hip arthroplasties with sixty-three (10%) re-revisions were evaluated. The mean cohort age (and standard deviation) was 57.0 ± 12.4 years, the mean body mass index (and standard deviation) was 29.5 ± 6.1 kg/m(2), and most of the patients were women (64.5%) and white (81.9%) and had an American Society of Anesthesiologists score of <3 (52.9%). The five-year implant survival after revision total hip arthroplasty was 86.8% (95% confidence interval, 83.57% to 90.25%). In adjusted models, age, total number of revision surgical procedures performed by the surgeon, fixation, and bearing surface were associated with the risk of re-revision. For every ten-year increase in patient age, the hazard ratio for re-revision decreases by a factor of 0.72 (95% confidence interval, 0.58 to 0.90). For every five revision surgical procedures performed by a surgeon, the risk of revision decreases by a factor of 0.93 (95% confidence interval, 0.86 to 0.99). At the time of revision, a new or retained cemented femoral implant or all-cemented hip implant increases the risk of revision by a factor of 3.19 (95% confidence interval, 1.22 to 8.38) relative to a retained or new uncemented hip implant. A ceramic on a highly cross-linked polyethylene bearing articulation decreases the hazard relative to metal on highly cross-linked polyethylene by a factor of 0.32 (95% confidence interval, 0.11 to 0.95). Metal on constrained bearing increases the hazard relative to metal on highly cross-linked polyethylene by a factor of 3.32 (95% confidence interval, 1.16 to 9.48). When evaluating patient, implant, and surgical factors at the time of revision total hip arthroplasty, age, surgeon experience, implant fixation, and bearing surfaces had significant impacts on the risk of re-revision. Copyright © 2015 by The Journal of Bone and Joint Surgery, Incorporated.

  7. Application of individually performed acrylic cement spacers containing 5% of antibiotic in two-stage revision of hip and knee prosthesis due to infection.

    PubMed

    Babiak, Ireneusz

    2012-07-03

    Deep infection of a joint endoprosthesis constitutes a threat to the stability of the implant and joint function. It requires a comprehensive and interdisciplinary approach, involving the joint revision and removal of the bacterial biofilm from all tissues, the endoprosthesis must be often removed and bone stock infection treated. The paper presents the author's experience with the use of acrylic cement spacers, custom-made during the surgery and containing low dose of an antibiotic supplemented with 5% of a selected, targeted antibiotic for the infection of hip and knee endoprostheses. 33 two-stage revisions of knee and hip joints with the use of a spacer were performed. They involved 24 knee joints and 9 hip joints. The infections were mostly caused by staphylococci MRSA (18) and MSSA (8), and in some cases Enterococci (4), Salmonella (1), Pseudomonas (1) and Acinetobacter (1). The infection was successfully treated in 31 out of 33 cases (93.93%), including 8 patients with the hip infection and 23 patients with the knee infection. The endoprosthesis was reimplanted in 30 cases: for 7 hips and 23 knees, in 3 remaining cases the endoprosthesis was not reimplanted. Mechanical complications due to the spacer occurred in 4 cases: 3 dislocations and 1 fracture (hip spacer). The patients with hip spacers were ambulatory with a partial weight bearing of the operated extremity and those with knee spacers were also ambulatory with a partial weight bearing, but the extremity was initially protected by an orthosis. The spacer enables to maintain a limb function, and making it by hand allows the addition of the specific bacteria targeted antibiotic thus increasing the likelihood of the effective antibacterial treatment.

  8. Patient Needs for an Ambulant Dislocation Alert System Following Total Hip Arthroplasty.

    PubMed

    Huis In't Veld, Rianne; Peters, Anil; Vollenbroek-Hutten, Miriam; Hermens, Hermie; van den Hoven, Carmen

    2018-05-01

    One of the major complications in total hip arthroplasty (THA) is dislocation of the prosthesis. To prevent early dislocation, patients are instructed with movement restrictions. The first goal in this development is to obtain insight in the movement restrictions that are reported to have low levels of self-efficacy during activities of daily life. The second goal is to reveal the design needs for an ambulant hip dislocation alert system (HipDas) and the third goal is to explore its usability among patients. Patient-centered experiences with THA were explored by the use of a questionnaire and a semistructured focus group. The questionnaire was administered among n = 32 THA patients at 1 week preoperative and at 3 and 6 weeks postoperative. The questions addressed self-efficacy, performance and effort expectancy, and usefulness and social influence. The focus group consisted of patient journeys and scenario composition. The usability of a prototype version of the HipDas system was evaluated (n = 5). Flexion of the hip >90°, bending over while sitting in a chair, and sleeping in a supine position are the restrictions that have the lowest self-efficacy. The majority of patients (>86.6%) believe that a future HipDas is useful. Focus group outcomes suggest there is a gradual decrease in the threshold for feedback. The system is preferably used in the first 6 weeks after surgery and appeared to be usable and highly clinically relevant. HipDas is considered an interesting concept that can accelerate functional recovery of patients following THA by providing support on how to properly apply postoperative movement restrictions to prevent a dislocation.

  9. Automated generation of IMRT treatment plans for prostate cancer patients with metal hip prostheses: Comparison of different planning strategies

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Voet, Peter W. J.; Dirkx, Maarten L. P.; Breedveld, Sebastiaan

    2013-07-15

    Purpose: To compare IMRT planning strategies for prostate cancer patients with metal hip prostheses.Methods: All plans were generated fully automatically (i.e., no human trial-and-error interactions) using iCycle, the authors' in-house developed algorithm for multicriterial selection of beam angles and optimization of fluence profiles, allowing objective comparison of planning strategies. For 18 prostate cancer patients (eight with bilateral hip prostheses, ten with a right-sided unilateral prosthesis), two planning strategies were evaluated: (i) full exclusion of beams containing beamlets that would deliver dose to the target after passing a prosthesis (IMRT{sub remove}) and (ii) exclusion of those beamlets only (IMRT{sub cut}). Plansmore » with optimized coplanar and noncoplanar beam arrangements were generated. Differences in PTV coverage and sparing of organs at risk (OARs) were quantified. The impact of beam number on plan quality was evaluated.Results: Especially for patients with bilateral hip prostheses, IMRT{sub cut} significantly improved rectum and bladder sparing compared to IMRT{sub remove}. For 9-beam coplanar plans, rectum V{sub 60Gy} reduced by 17.5%{+-} 15.0% (maximum 37.4%, p= 0.036) and rectum D{sub mean} by 9.4%{+-} 7.8% (maximum 19.8%, p= 0.036). Further improvements in OAR sparing were achievable by using noncoplanar beam setups, reducing rectum V{sub 60Gy} by another 4.6%{+-} 4.9% (p= 0.012) for noncoplanar 9-beam IMRT{sub cut} plans. Large reductions in rectum dose delivery were also observed when increasing the number of beam directions in the plans. For bilateral implants, the rectum V{sub 60Gy} was 37.3%{+-} 12.1% for coplanar 7-beam plans and reduced on average by 13.5% (maximum 30.1%, p= 0.012) for 15 directions.Conclusions: iCycle was able to automatically generate high quality plans for prostate cancer patients with prostheses. Excluding only beamlets that passed through the prostheses (IMRT{sub cut} strategy) significantly improved OAR sparing. Noncoplanar beam arrangements and, to a larger extent, increasing the number of treatment beams further improved plan quality.« less

  10. Biomechanical analysis of a novel hemipelvic endoprosthesis during ascending and descending stairs.

    PubMed

    Liu, Dongxu; Hua, Zikai; Yan, Xinyi; Jin, Zhongmin

    2016-10-01

    In this study, the biomechanical characteristic of a newly developed adjustable hemipelvic prosthesis under dynamic loading conditions was investigated using explicit finite element method. Both intact and reconstructed pelvis models, including pelvis, femur and soft tissues, were established referring to human anatomic data using a solid geometry of a human pelvic bone. Hip contact forces during ascending stairs and descending stairs were imposed on pelvic models. Results showed that maximum von Mises stresses in reconstructed pelvis were 421.85 MPa for prostheses and 109.12 MPa for cortical bone, which were still within a low and elastic range below the yielding strength of Ti-6Al-4V and cortical bone, respectively. Besides, no significant difference of load transferring paths along pelvic rings was observed between the reconstructed pelvis and natural pelvis models. And good agreement was found between the overall distribution of maximum principal stresses in trabecular bones of reconstructed pelvis and natural pelvis, while at limited stances, principal stresses in trabecular bone of reconstructed pelvis were slightly lower than natural pelvis. The results indicated that the load transferring function of pelvis could be restored by this adjustable hemipelvic prosthesis. Moreover, the prosthesis was predicted to have a reliable short- and long-term performance. However, due to the occurrence of slightly lower principal stresses at a few stances, a porous structure applied on the interface between the prosthesis and bone would be studied in future work to obtain better long-term stability. © IMechE 2016.

  11. Reduction of metallosis in hip implant using thin film coating

    NASA Astrophysics Data System (ADS)

    Rajeshshyam, R.; Chockalingam, K.; Gayathri, V.; Prakash, T.

    2018-04-01

    Hip implant finds its emerging attraction due to it continuous demand over the years. The hip implants (femoral head) and acetabulum cup) mainly fabricated by metals such as stainless steel, cobalt chrome and titanium alloys, other than that ceramics and polyethylene have been used. The metal-on-metal hip implant was found to be best implant material for most of the surgeons due to its high surface finish, low wear rate and low chance of dislocation from its position after implanting. Where in metal based hip implant shows less wear rate of 0.01mm3/year. Metal-on-metal implant finds its advantage over other materials both in its mechanical and physical stability against human load. In M-O-M Cobalt- chromium alloys induce metal allergy. The metal allergy (particulate debris) that is generated by wear, fretting, fragmentation and which is unavoidable when a prosthesis is implanted, can induce an inflammatory reaction in some circumstances. The objectives of this research to evaluate thin film coating with Nano particle additives to reduce the wear leads to regarding metal ion release. Experimental results reveals that thin film Sol-Gel coating with 4wt. % of specimen reduced the cobalt and chromium ion release and reduces the wear rate. Wear rate reduced by 98% for 4wt. % graphene in 20N and 95% for 4wt. % graphene in 10N.

  12. The influence of resting periods on friction in the artificial hip.

    PubMed

    Nassutt, Roman; Wimmer, Markus A; Schneider, Erich; Morlock, Michael M

    2003-02-01

    Insufficient tribologic performance of total joint components is a major cause of prostheses failure. Wear has been studied intensively using testing machines that apply continuous motions. Human locomotion, however, is not well represented by continuous motions alone. Singular events and resting periods are a substantial part of daily activities. Resting does influence adhesion in the artificial joint with possible effects on friction, wear, and loosening. The current study evaluated the effects of resting on the frictional properties of hip prosthesis components. The activity measurements of 32 patients with artificial hip replacements were analyzed for resting durations of the hip. A pin-on-ball screening device was used to determine friction after characteristic resting periods and during continuous oscillating motion. All common articulation pairings were investigated. Prolonged and frequent resting periods of the hip were found for the patients. Initial friction increased with increasing resting duration for all tested materials (between 41% and 191%). The metal-on-metal articulations showed the highest friction level (0.098 for sliding) and the highest increase (191%) in friction with resting duration (0.285 after resting periods of 60 seconds). A high static frictional moment after resting periods might present a risk for aseptic implant loosening. Therefore, large head diameters of metal-on-metal joints should be used with caution, especially when additional unfavorable risk factors such as obesity, weak bone-implant interface, or high activity level are present.

  13. Relatively High Complication and Revision Rates of the Mayo® Metaphysical Conservative Femoral Stem in Young Patients.

    PubMed

    Rutenberg, Tal Frenkel; Warshevski, Yaniv; Gold, Aviram; Shasha, Nadav; Snir, Nimrod; Chechik, Ofir; Dolkart, Oleg; Eilig, Dynai; Herman, Amir; Rath, Ehud; Kramer, Moti; Drexler, Michael

    2018-05-08

    The Mayo metaphysical conservative femoral stem (Zimmer, Warsaw, Indiana) is a wedge-shaped implant designed to transfer loads proximally, reduce femoral destruction, and enable the preservation of bone stock in the proximal femur. Thus, it is a potentially preferred prosthesis for active, non-elderly patients who may require additional future surgeries. This retrospective case study analyzed the outcomes of consecutive patients who underwent total hip replacements with this stem between May 2001 and February 2013. All patients underwent clinical assessment, radiological evaluation for the presence and development of radiolucent lines, and functional assessment (numerical analog scale, Harris hip score, and Short Form-12 questionnaire). Ninety-five hips (79 patients) were available for analysis. The patients' mean age was 43 years (range, 18-64 years), and the mean follow-up was 97 months (range, 26.9-166 months). The postoperative clinical assessments and functional assessments revealed significant improvements. Sixteen patients (20.3%) had 18 orthopedic complications, the most common of which were an intraoperative femoral fracture and implant dislocation requiring revision surgeries in 10 hips (10.5%). Radiological analysis revealed evidence of femoral remodeling in 64 (67.4%) implants, spot welds (neocortex) in 35 (36.8%), and osteolysis in 3 (3.2%). These results suggest that the conservative hip femoral implant has an unacceptable complication rate for non-elderly patients. [Orthopedics. 201x; xx(x):xx-xx.]. Copyright 2018, SLACK Incorporated.

  14. Primary cementless total hip arthroplasty with second-generation metal-on-metal bearings: a concise follow-up, at a minimum of seventeen years, of a previous report.

    PubMed

    Lass, R; Grübl, A; Kolb, A; Domayer, S; Csuk, C; Kubista, B; Giurea, A; Windhager, R

    2014-03-05

    Second-generation, metal-on-metal bearings were introduced in 1988, to reduce wear and avoid polyethylene particle-induced osteolysis from total hip arthroplasty. In 2007, we reported the long-term results of ninety-eight patients (105 hips) who underwent primary cementless total hip arthroplasty involving the use of a prosthesis with a high-carbide-concentration, metal-on-metal articulating surface between November 1992 and May 1994. The present study gives an update on this patient cohort. At a minimum of seventeen years postoperatively, forty-nine patients (fifty-two hips) were available for follow-up examination. We retrospectively evaluated clinical and radiographic results as well as serum metal concentration. The mean patient age at the time of the index arthroplasty was fifty-six years. Three cups (6% of the hips) and one stem (2% of the hips) were revised because of aseptic loosening of the implants combined with focal osteolysis. At the time of the latest follow-up evaluation, the mean Harris hip score was 88.8 points, and the mean University of California Los Angeles (UCLA) activity score was 6.7 points. The cumulative rate of implant survival, with aseptic failure as the end point, was 93.0% at 18.8 years. The median serum cobalt concentration in patients whose hip implant was the only source of cobalt was 0.70 μg/L (range, 0.4 to 5.1 μg/L), showing no increase in the value as noted at a minimum of ten years of follow-up. The clinical and radiographic results of our study, which, to our knowledge, represent the longest duration of follow-up for a series of cementless total hip arthroplasties with use of a 28-mm metal-on-metal bearing, continue to be comparable with the results observed for other hard-on-hard bearings.

  15. The use of interlocking prostheses for both temporary and definitive management of infected periprosthetic femoral fractures.

    PubMed

    Konan, Sujith; Rayan, Faizal; Manketelow, Andrew R J; Haddad, Fares S

    2011-12-01

    Infected periprosthetic fractures around total hip arthroplasties are an extremely challenging problem. We describe our experience of managing infected periprosthetic femoral fractures using interlocking long-stem femoral prostheses either as temporary functional spacers or as definitive implants. The Cannulock (Orthodesign, Christchurch, United Kingdom) uncoated stem was used in 12 cases, and the Kent hip prosthesis (Biomet Merck, Bridgend, United Kingdom), in 5 cases. Satisfactory outcome was noted in all cases, and in 11 cases, revision to a definitive stem has been undertaken after successful control of infection and fracture union. The use of interlocking stems offers a relatively appealing solution for a complex problem and avoids the complications that would be associated with resection of the entire femur or the use of large quantities of bone cement. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. Identification of the Cause of the Stem Neck Fracture in the Hip Joint Endoprosthesis

    NASA Astrophysics Data System (ADS)

    Ryniewicz, A. M.; Bojko, Ł.; Ryniewicz, A.; Pałka, P.; Ryniewicz, W.

    2018-02-01

    Endoprosthesis stem fractures are among the rarest complications that occur after hip joint arthroplasty. The aim of this paper is to evaluate the causes of the fractures of the Aura II stem neck, which is an element of an endoprosthesis implanted in a patient. In order to achieve it, a radiogram was evaluated, the FEM analysis was carried out for the hip joint replaced using the Aura II prosthesis and scanning tests as well as a chemical analysis were performed for the focus of fatigue. The tests performed indicate that the most probable causes leading to the fatigue fracture of the Aura II stem under examination were material defects in the process of casting and forging (forging the material with delamination and the presence of brittle oxides and carbides) that resulted in a significant reduction of strength and resistance to corrosion. In the light of an unprecedented stem neck fracture, this information should be an indication for non-destructive tests of ready-made stems aiming to discover the material and technological defects that may arise in the process of casting and drop forging.

  17. Integral multidisciplinary approach in a patient with chronic complete spinal cord injury and hip disarticulation

    PubMed Central

    Quinzaños-Fresnedo, J; Rodríguez-Reyes, G; Mendoza-Cosío, C; Pérez-Zavala, R; Márquez-Guitérrez, E A; Hernández-Sandoval, S

    2015-01-01

    Study design: Case report. Objectives: To highlight the importance of the integral multidisciplinary management of a patient with complete chronic spinal cord injury and hip disarticulation secondary to pressure ulcers (PU). Setting: Mexico City. Methods: The case of a 40-year-old male violinist with a spinal cord injury, American Spinal Injury Association Impairment Scale A and neurological level T4, is reported. The patient initiated with bilateral ischiatic, left trochanteric and sacral PU. The ulcers were complicated with infection with sluggish evolution. Thus, it was decided a multidisciplinary management by means of left hip disarticulation and elaboration of a cosmetic prosthesis and the manufacture of a viscous elastic foam cushion for the prevention of new PU. The patient was quickly included in his professional and social activities. Conclusion: This study proves that multidisciplinary management of patients with spinal cord injury with complications such as the presence of PU that are resistant to noninvasive treatment can be the solution for the patient’s reintegration into their normal life with adequate quality of life. PMID:28053719

  18. Detection of total hip arthroplasties at airport security checkpoints - how do updated security measures affect patients?

    PubMed

    Issa, Kimona; Pierce, Todd P; Gwam, Chukwuweieke; Festa, Anthony; Scillia, Anthony J; Mont, Michael A

    2018-03-01

    There have been historical reports on the experiences of patients with total hip arthroplasty (THA) passing through standard metal detectors at airports. The purpose of this study was to analyse those who had recently passed through airport security and the incidence of: (i) triggering of the alarm; (ii) extra security searches; and (iii) perceived inconvenience. A questionnaire was given to 125 patients with a THA during a follow-up appointment. Those who had passed through airport security after January 2014 met inclusion criteria. A survey was administered that addressed the number of encounters with airport security, frequency of metal detector activation, additional screening procedures utilised, whether security officials required prosthesis documentation, and perceived inconvenience. 51 patients met inclusion criteria. 10 patients (20%) reported triggered security scanners. 4 of the 10 patients stated they had surgical hardware elsewhere in the body. 13 of the 51 patients (25%) believed that having their THA increased the inconvenience of traveling. This is different from the historical cohort with standard metal detectors which patients reported a greater incidence of alarm triggering (n = 120 of 143; p = 0.0001) and perceived inconvenience (n = 99 of 143; p = 0.0001). The percentage of patients who have THA triggering security alarms has decreased. Furthermore, the number of patients who feel that their prosthesis caused traveling inconvenience has decreased. We feel that this decrease in alarms triggered and improved perceptions about inconvenience are related to the increased usage of new technology.

  19. Comparative study of fat-suppression techniques for hip arthroplasty MR imaging.

    PubMed

    Molière, Sébastien; Dillenseger, Jean-Philippe; Ehlinger, Matthieu; Kremer, Stéphane; Bierry, Guillaume

    2017-09-01

    The goal of this study was to evaluate different fat-suppressed fluid-sensitive sequences in association with different metal artifacts reduction techniques (MARS) to determine which combination allows better fat suppression around metallic hip implants. An experimental study using an MRI fat-water phantom quantitatively evaluated contrast shift induced by metallic hip implant for different fat-suppression techniques and MARS. Then a clinical study with patients addressed to MRI unit for painful hip prosthesis compared these techniques in terms of fat suppression quality and diagnosis confidence. Among sequences without MARS, both T2 Dixon and short tau inversion recuperation (STIR) had significantly lower contrast shift (p < 0.05), Dixon offering the best fat suppression. Adding MARS (view-angle tilting or slice-encoding for metal artifact correction (SEMAC)) to STIR gave better results than Dixon alone, and also better than SPAIR and fat saturation with MARS (p < 0.05). There were no statistically significant differences between STIR with view-angle tilting and STIR with SEMAC in terms of fat suppression quality. STIR sequence is the preferred fluid-sensitive MR sequence in patients with metal implant. In combination with MARS (view-angle tilting or SEMAC), STIR appears to be the best option for high-quality fat suppression.

  20. [Technology of cementless hip endoprosthetics].

    PubMed

    Ungethüm, M; Blömer, W

    1987-06-01

    The success achieved with non-cemented hip arthroplasty depends mainly on the stability of the fixation, the quality of the stabilizing bone being just as important as favourable biomechanical conditions. The results of the intensive research and development with respect to the particular features of a non-cemented hip endoprosthesis can be divided into the following basic categories: Biomechanical aspects with special reference to bone related to the design of the prosthesis; material characteristics, such as fatigue strength, tribology, corrosion resistance, and biocompatibility; and development of new materials and coatings to permit direct bonding of implant and bone. With regard to the stem of hip prostheses, the different design parameters of various types are examined to determine their typical design characteristics, such as bearing surface of the collar, geometry of cross section, anatomically adapted shaping, and surface of the implant forming the contact with the bone. The latter can be divided into macroprofiles and macro- and micro-porous coated surfaces. On the other hand, the methods of cementless fixation of acetabular cups can be primarily divided into conical and spherical screw fixation and pegged fixation with additional macroprofiles of porous surfaces. In a separate study of the biomechanical aspects of screwed sockets, the special importance of socket shape and thread geometry are presented with reference to primary stability and long-term fixation of prostheses.

  1. Effect of rivaroxaban on preventing deep vein thrombosis in aged diabetics with femoral neck fractures after hip replacement

    PubMed Central

    Jiang, Xin; Sun, Yan-Shan

    2017-01-01

    The present study estimates the effect of rivaroxaban on preventing deep vein thrombosis (DVT) in aged diabetics with femoral neck fractures after hip replacement. Our study consisted of 236 aged diabetics with femoral neck fractures, which were divided into the rivaroxaban and control groups. Reaction time (R time), clot formation time (K time), α angle (α), maximum amplitude (MA), clot elasticity (G) and coagulation index (CI), prothrombin time (PT) and activated partial thromboplastin time (APTT) were measured. DVT was diagnosed by color duplex Doppler ultrasound (CDDU). The risk factors of DVT were analysed by logistic regression analysis. Compared with the control group, in the rivaroxaban group, R time and K time were extended and α, MA and G decreased 1 day before operation. One day after operation, the rivaroxaban group had less PT and APPT and lower incidence of DVT than the control group. In the two groups, preoperative and postoperative PT and APPT significantly differed. Body mass index (BMI) ≥25, abnormal coagulation indicators, use of cemented femoral hip prosthesis, high haemoglobin content and non-ankle pump exercise after operation were the risk factors for DVT. Rivaroxaban could prevent DVT in aged diabetics with femoral neck fractures after hip replacement. PMID:28442600

  2. Incidence and Risk Factors for Health-Care Associated Infections after Hip Operation.

    PubMed

    Hessels, Amanda J; Agarwal, Mansi; Liu, Jianfang; Larson, Elaine L

    2016-12-01

    Hip operation reduces pain and improves mobility and quality of life for more than 300,000 people annually, most of whom are more than 65 years old. Substantial increases in surgical volume are projected between 2005 and 2030 in primary total (174%) and revision (137%) procedures. This projection demands that the impact of increasing age on the relative risk of health-care associated infections (HAI) after hip surgical procedures be assessed. Our aim was to examine the incidence and risk factors of HAI among patients who underwent hip operations between 2006 and 2012. This secondary analysis included data from patients 18 years old or older and having a hip prosthesis procedure in three New York City hospitals between 2006 and 2012. Procedures were categorized as total or partial hip replacements or revision and re-surfacing procedures. Outcomes of interest were blood stream infections (BSI), urinary tract infections (UTI), or surgical site infections (SSI). Patients in whom an infection developed during the hospital visit in which the hip procedure occurred were counted as cases. Of 2021 patients, approximately 11% (n = 218) had an HAI. There was no difference in infection rates by admission year despite an increase in surgical volume. SSI was associated with younger age, previous hospitalization, and hip revision surgical procedure whereas UTI and BSI were associated with older age, greater co-morbidity, longer pre-operative length of stay and intensive care unit stay, (p < 0.05). HAI after hip operation affected approximately one in 10 patients over a 7-year period in three high-volume hospitals. SSI occurred least frequently, predominantly among patients who underwent revision surgery (without previous SSI), were younger, and had a history of previous hospitalization. Infections such as BSI and UTI, although rare, occurred more frequently and in patients with more co-morbidities, longer pre-operative length of stay, and who required higher level care. Further research to understand these unexpected findings and target interventions is warranted.

  3. Gluteal muscle attachment during proximal femoral reconstruction in a canine model.

    PubMed

    Pluhar, G Elizabeth; Manley, Paul A; Heiner, John P; Vanderby, Ray; Markel, Mark D

    2007-02-01

    In this 18 month in vivo canine study we compared three methods of attaching the gluteal muscles to the proximal femur during hip reconstruction with an allograft-prosthesis composite (APC). All three methods are commonly practiced in human hip revision surgery and data on their effectiveness in dogs is directly relevant to human treatment. The methods compared were host gluteal tendon sutured to allograft tendon, host greater trochanter apposed to allograft using a cable grip system, and host cortical bone shells around the allograft secured with cerclage wires. For each method, we assessed changes in allograft-host bone fusion, weight bearing, gluteal muscle mass, and structural properties through qualitative radiography, gait analysis, histology, and biomechanical testing. Hip reconstruction using the WRAP method resulted in the greatest limb use with complete resolution of gluteal muscle atrophy 18 months after surgery. This method yielded a stronger, more stable hip joint that allowed for more normal limb function. These hips had the more rapid rate of bony union at the host bone-allograft junction and little resorption of the graft. The increased limb use and resultant larger gluteal muscle mass conferred to the WRAP hip composites the greatest tensile strength and stiffness when tested 18 months after reconstruction. There was a large amount of new bone formation on the periosteal surface where the WRAP reconstructions had an overlay of live bone that resulted in a more rapid union and increased cortical width at the level of the osteotomy. New bone also penetrated into the allograft a greater distance from the osteotomy in the WRAP group.

  4. Accuracy of femoral templating in reproducing anatomical femoral offset in total hip replacement.

    PubMed

    Davies, H; Foote, J; Spencer, R F

    2007-01-01

    Restoration of hip biomechanics is a crucial component of successful total hip replacement. Preoperative templating is recommended to ensure that the size and orientation of implants is optimised. We studied how closely natural femoral offset could be reproduced using the manufacturers' templates for 10 femoral stems in common use in the UK. A series of 23 consecutive preoperative radiographs from patients who had undergone unilateral total hip replacement for unilateral osteoarthritis of the hip was employed. The change in offset between the templated position of the best-fitting template and the anatomical centre of the hip was measured. The templates were then ranked according to their ability to reproduce the normal anatomical offset. The most accurate was the CPS-Plus (Root Mean Square Error 2.0 mm) followed in rank order by: C stem (2.16), CPT (2.40), Exeter (3.23), Stanmore (3.28), Charnley (3.65), Corail (3.72), ABG II (4.30), Furlong HAC (5.08) and Furlong modular (7.14). A similar pattern of results was achieved when the standard error of variability of offset was analysed. We observed a wide variation in the ability of the femoral prosthesis templates to reproduce normal femoral offset. This variation was independent of the seniority of the observer. The templates of modern polished tapered stems with high modularity were best able to reproduce femoral offset. The current move towards digitisation of X-rays may offer manufacturers an opportunity to improve template designs in certain instances, and to develop appropriate computer software.

  5. [Intra-prosthetic dislocation of the Bousquet dual mobility socket].

    PubMed

    Lecuire, F; Benareau, I; Rubini, J; Basso, M

    2004-05-01

    The Bousquet system is a dual mobility head-polyethylene polyethylene-metal cup socket. The polyethylene insert retaining the femoral head moves in the noncemented metal cup, increasing both mobility and stability. Between 1989 and 1997, seven cases of intra-prosthetic dislocation (six patients) were observed. The femoral head escaped from the polyethylene insert due to wear. On the average, this complication occurred ten Years after implantation. Risk of dislocation was high in six of the seven hips. All patients had a large sized stem screwed into the femoral neck. There was a characteristic radiological aspect with loss of the concentric head metal cup configuration. The head was applied against the upper wall of the metal cup. Surgical replacement was undertaken early in six patients by simply changing the insert without modifying the other stable components. Outcome remained good at three to eight Years. One patient underwent late surgery. The insert and the cup were replaced with a classical implant. Functional outcome was good but recurrent dislocation occurred. At mid-term, intra-prosthetic dislocation of dual mobility sockets appears to be exceptional. Dislocation results from polyethylene wear leading to failure of the insert to retain the prosthetic head. Wear is favored by direct phenomena (direct contact between neck and insert which can occur early if there is a small difference in the head and neck diameters) or indirect phenomena (factors limiting polyethylene metal-cup mobility). Surgical treatment is necessary. If undertaken early, replacement with a modular head and insert can be sufficient if the prosthesis has not loosened but the metal cup may have to be replaced in the event of metal-metal contact between the head and the cup. Prosthesis loosening, wear of the metal cup, or an identified cause of dislocation imply replacing the failing implants. Implantation of the dual mobility system is particularly interesting for patients with a high risk of dislocation or a chronically unstable hip prosthesis. Careful technique is required to reduce or retard the risk of intra-prosthetic dislocation. Intra-prosthetic dislocation of a dual mobility socket is an exceptional complication at mid-term. Surgical treatment is required but may be limited to simple insert replacement. Systematic use of this type of implant in young subjects must be carefully examined, but for us, the risk of dislocation does not outweigh the advantages of this original concept of dual mobility. This type of socket remains an useful preventive technique for high-risk hips or for curative treatment of recurrent dislocation.

  6. Association of Airborne Microorganisms in the Operating Room With Implant Infections: A Randomized Controlled Trial.

    PubMed

    Darouiche, Rabih O; Green, David M; Harrington, Melvyn A; Ehni, Bruce L; Kougias, Panagiotis; Bechara, Carlos F; O'Connor, Daniel P

    2017-01-01

    OBJECTIVE To evaluate the association of airborne colony-forming units (CFU) at incision sites during implantation of prostheses with the incidence of either incisional or prosthesis-related surgical site infections. DESIGN Randomized, controlled trial. SETTING Primary, public institution. PATIENTS Three hundred patients undergoing total hip arthroplasty, instrumented spinal procedures, or vascular bypass graft implantation. METHODS Patients were randomly assigned in a 1:1 ratio to either the intervention group or the control group. A novel device (Air Barrier System), previously shown to reduce airborne CFU at incision sites, was utilized in the intervention group. Procedures assigned to the control group were performed without the device, under routine operating room atmospheric conditions. Patients were followed up for 12 months to determine whether airborne CFU levels at the incision sites predicted the incidence of incisional or prosthesis-related infection. RESULTS Data were available for 294 patients, 148 in the intervention group and 146 in the control group. CFU density at the incision site was significantly lower in the intervention group than in the control group (P<.001). The density of airborne CFU at the incision site during the procedures was significantly related to the incidence of implant infection (P=.021). Airborne CFU densities were 4 times greater in procedures with implant infection versus no implant infection. All 4 of the observed prosthesis infections occurred in the control group. CONCLUSION Reduction of airborne CFU specifically at the incision site during operations may be an effective strategy to reduce prosthesis-related infections. clinicaltrials.gov Identifier: NCT01610271 Infect Control Hosp Epidemiol 2016;1-8.

  7. A general model for estimating lower extremity inertial properties of individuals with transtibial amputation.

    PubMed

    Ferris, Abbie E; Smith, Jeremy D; Heise, Gary D; Hinrichs, Richard N; Martin, Philip E

    2017-03-21

    Lower extremity joint moment magnitudes during swing are dependent on the inertial properties of the prosthesis and residual limb of individuals with transtibial amputation (TTA). Often, intact limb inertial properties (INTACT) are used for prosthetic limb values in an inverse dynamics model even though these values overestimate the amputated limb's inertial properties. The purpose of this study was to use subject-specific (SPECIFIC) measures of prosthesis inertial properties to generate a general model (GENERAL) for estimating TTA prosthesis inertial properties. Subject-specific mass, center of mass, and moment of inertia were determined for the shank and foot segments of the prosthesis (n=11) using an oscillation technique and reaction board. The GENERAL model was derived from the means of the SPECIFIC model. Mass and segment lengths are required GENERAL model inputs. Comparisons of segment inertial properties and joint moments during walking were made using three inertial models (unique sample; n=9): (1) SPECIFIC, (2) GENERAL, and (3) INTACT. Prosthetic shank inertial properties were significantly smaller with the SPECIFIC and GENERAL model than the INTACT model, but the SPECIFIC and GENERAL model did not statistically differ. Peak knee and hip joint moments during swing were significantly smaller for the SPECIFIC and GENERAL model compared with the INTACT model and were not significantly different between SPECIFIC and GENERAL models. When subject-specific measures are unavailable, using the GENERAL model produces a better estimate of prosthetic side inertial properties resulting in more accurate joint moment measurements for individuals with TTA than the INTACT model. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Intravascular migration of a broken cerclage wire into the left heart.

    PubMed

    Leonardi, Francesco; Rivera, Fabrizio

    2014-10-01

    This article describes a patient in whom a broken cerclage wire migrated from the left hip into the left ventricle. A 71-year-old woman was admitted to the authors' hospital for preoperative examination before femoral hernia repair. Chest radiograph showed a metallic wire in the left ventricle. Twenty-four years earlier, she had a revision arthroplasty. During revision surgery, fragments of the osteotomy were fixed to the femur with multiple cerclage wires. During the past 5 years, radiographic follow-up showed progressive multiple ruptures of cerclage wires. The cerclage wiring was not removed because the patient had no related clinical symptoms. Radiograph of the left hip showed a well-fixed cemented acetabular ring and an uncemented femoral stem with a healed trochanteric osteotomy. All cerclage wires were broken into multiple parts, and it was very difficult to determine which part had migrated into the heart. Thoracic computed tomography scan showed wire that had migrated into the anterior left ventricular myocardial wall at the atrioventricular level. The patient had no clinical symptoms. Electrocardiogram showed a normal sinus rhythm and right bundle branch block. Because of the high risk of surgical left ventriculotomy associated with searching for wire that had migrated into the myocardial wall, patient monitoring was planned. Definitive management of this complication constitutes a dilemma. Although this complication is highly unusual, the possibility of intracardiac migration of broken wire should be considered when deciding on prophylactic surgical removal of hardware after fracture or osteotomy healing. Copyright 2014, SLACK Incorporated.

  9. Anatomical and biomechanical investigations of the iliotibial tract.

    PubMed

    Birnbaum, K; Siebert, C H; Pandorf, T; Schopphoff, E; Prescher, A; Niethard, F U

    2004-12-01

    Divergent descriptions of the anatomic location and biomechanical function of the iliotibial tract (IT) can be found in the literature. This study attempted to obtain exact data regarding the anatomic course and material characteristics including the biomechanical properties of this structure. The following were its aims: (1) anatomical investigations of the IT; (2) mechanical properties of the IT; (3) femoral head centralizing force of the IT and subligamentous forces in the height of the greater trochanter in different joint positions by using a custom-made measuring prosthesis and a subligamentous positioned sensor; (4) construction of a finite element model of the proximal femur including the IT and measuring the femoral neck angle under variation. The hip joints and IT in a total of 18 unfixed corpses were evaluated. We studied the anatomic relationship to surrounding structures, as well as the material properties with the help of tensile strength testing utilizing an uniaxial apparatus. During the test, a load-displacement curve was registered, documenting the maximum load and deformation of the IT. To measure the subligamentous pressure at the height of the greater trochanter, a custom-made sensor with a power-recording instrument was constructed. Furthermore, an altered hip prosthesis with a pressure gauge at the height of the femoral neck was used to measure the forces which are directed at the acetabulum. The investigations were done in neutral-0 position and ab/adduction of the hip joint of the unfixed corpse. In addition, we varied the femoral neck angle between 115 degrees and 155 degrees in 5 degrees steps. To confirm the subligamentous forces, we did the same measurements intraoperatively at the height of the greater trochanter before and after hip joint replacement in 12 patients. We constructed a finite element model of the proximal femur and considering the IT. The acquisition of the data was done at physiological (128 degrees), varus (115 degrees), and valgus (155 degrees) femoral neck angles. The influencing forces of the IT at the height of the greater trochanter and the forces at the femoral head or the acetabulum could be measured. Our anatomical investigations revealed a splitting of the IT into a superficial and a deep portion, which covers the tensor fasciae latae. The tensor fasciae latae has an insertion on the IT. The IT continues down the femur, passing over the greater trochanter without developing an actual fixation to the bone. Part of the insertion of the gluteus maximus radiates into the IT. The IT passes over the vastus lateralis and inserts at the infracondylar tubercle of the tibia or Gerdy's tubercle, at the head of the fibula, as well as at the lateral intermuscular septum. Portions also insert on the transverse and longitudinal retinaculum of the patella. Concerning the material properties of the IT, we found a structural stiffness of 17 N/mm extension on average (D = 17 N/mm). The subligamentous measurements at the height of the greater trochanter in the unfixed corpse and intraoperatively during hip joint replacement showed an increase of the forces during adduction and a decrease during abduction of the hip joint. We found thereby a maximum increase up to 106 N with 40 degrees adduction. Concerning the femoral neck angle, we can state that valgus leads to lower subligamentous forces and varus to higher subligamentous forces. The forces directed at the acetabulum, which were measured by the prosthesis with a sensor along the femoral neck, showed a decrease with varus angles and an increase with valgus angles. The highest force of 624 N was measured with 40 degrees adduction and an angle of 155 degrees. The finite element model of the proximal femur showed a sole hip joint-centralizing force of the IT of 655 N with a femoral neck angle of 128 degrees after subtraction of the gluteal muscle force and the body weight. At 115 degrees, we found an increase up to 997 N and a decrease to 438 N at 155 degrees. Concerning the resulting forces in the acetabulum, we found opposite forces in comparison with the force of the IT at the height of the greater trochanter: at 115 degrees, a femoral head-centralizing force of 1601 N; at 128 degrees, 2360 N; and at 155 degrees, 2422 N. By our investigations, we can approximately prove the hip joint-centralizing force of the IT. By variation of the femoral neck angle and the position of the hip joint, we can predict the subligamentous force of the IT and the resulting force at the femoral head or at the acetabulum. The intraoperative measurement of the subligamentous forces of the IT is a good monitoring mechanism for the persistent hip-centralizing function of the IT in the course of hip joint replacement. The surgeon has the opportunity to check the stability of the hip joint after replacement. The finite element model gives the opportunity to check the divergent relative strength by variation of the femoral neck angle and the tension of the IT. In this way, the changes in the forces induced by a displacement osteotomy could be estimated preoperatively.

  10. Component Position and Metal Ion Levels in Computer-Navigated Hip Resurfacing Arthroplasty.

    PubMed

    Mann, Stephen M; Kunz, Manuela; Ellis, Randy E; Rudan, John F

    2017-01-01

    Metal ion levels are used as a surrogate marker for wear in hip resurfacing arthroplasties. Improper component position, particularly on the acetabular side, plays an important role in problems with the bearing surfaces, such as edge loading, impingement on the acetabular component rim, lack of fluid-film lubrication, and acetabular component deformation. There are little data regarding femoral component position and its possible implications on wear and failure rates. The purpose of this investigation was to determine both femoral and acetabular component positions in our cohort of mechanically stable hip resurfacing arthroplasties and to determine if these were related to metal ion levels. One hundred fourteen patients who had undergone a computer-assisted metal-on-metal hip resurfacing were prospectively followed. Cobalt and chromium levels, Harris Hip, and UCLA activity scores in addition to measures of the acetabular and femoral component position and angles of the femur and acetabulum were recorded. Significant changes included increases in the position of the acetabular component compared to the native acetabulum; increase in femoral vertical offset; and decreases in global offset, gluteus medius activation angle, and abductor arm angle (P < .05). Multiple regression analysis found no significant predictors of cobalt and chromium metal ion levels. Femoral and acetabular components placed in acceptable position failed to predict increased metal ion levels, and increased levels did not adversely impact patient function or satisfaction. Further research is necessary to clarify factors contributing to prosthesis wear. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. [Proposal for the classification of the periprosthetic membrane from loosened hip and knee endoprostheses].

    PubMed

    Morawietz, L; Gehrke, Th; Classen, R-A; Barden, B; Otto, M; Hansen, T; Aigner, Th; Stiehl, P; Neidel, J; Schröder, J H; Frommelt, L; Schubert, Th; Meyer-Scholten, C; König, A; Ströbel, Ph; Rader, Ch P; Kirschner, S; Lintner, F; Rüther, W; Skwara, A; Bos, I; Kriegsmann, J; Krenn, V

    2004-09-01

    After 10 years, loosening of total joint endoprostheses occurs in about 3 to 10 percent of all patients, requiring elaborate revision surgery. A periprosthetic membrane is routinely found between bone and loosened prosthesis. Further histomorphological examination allows determination of the etiology of the loosening process. Aim of this study is the introduction of clearly defined histopathological criteria for a standardized evaluation of the periprosthetic membrane. Based on histomorphological criteria and polarized light microscopy, four types of the periprosthetic membrane were defined: periprosthetic membrane of wear particle type (type I), periprosthetic membrane of infectious type (type II), periprosthetic membrane of combined type (type III), periprosthetic membrane of indifferent type (type IV). Periprosthetic membranes of 268 patients were analyzed according to the defined criteria. The correlation between histopathological and microbiological diagnosis was high (89%, p<0,001), the inter-observer reproducibility was sufficient (95%). This classification system enables a standardized diagnostic procedure and therefore is a basis for further studies concerning the etiology of and pathogenesis of prosthesis loosening.

  12. Blood loss associated with Ring uncemented total knee replacement: comparison between continuous and intermittent suction drainage.

    PubMed Central

    Wittmann, F W; Ring, P A

    1984-01-01

    In a retrospective comparison of blood loss following uncemented total knee replacement, in which either continuous or intermittent suction drainage was used, measured blood loss was significantly greater with continuous drainage. However, a method of calculating actual blood loss demonstrated no significant difference. With intermittent drainage, more blood remains undetected around the knee joint; this technique should therefore be abandoned in favour of continuous suction drainage. PMID:6747978

  13. Short-term outcome of 1,465 computer-navigated primary total knee replacements 2005-2008.

    PubMed

    Gøthesen, Oystein; Espehaug, Birgitte; Havelin, Leif; Petursson, Gunnar; Furnes, Ove

    2011-06-01

    and purpose Improvement of positioning and alignment by the use of computer-assisted surgery (CAS) might improve longevity and function in total knee replacements, but there is little evidence. In this study, we evaluated the short-term results of computer-navigated knee replacements based on data from the Norwegian Arthroplasty Register. Primary total knee replacements without patella resurfacing, reported to the Norwegian Arthroplasty Register during the years 2005-2008, were evaluated. The 5 most common implants and the 3 most common navigation systems were selected. Cemented, uncemented, and hybrid knees were included. With the risk of revision for any cause as the primary endpoint and intraoperative complications and operating time as secondary outcomes, 1,465 computer-navigated knee replacements (CAS) and 8,214 conventionally operated knee replacements (CON) were compared. Kaplan-Meier survival analysis and Cox regression analysis with adjustment for age, sex, prosthesis brand, fixation method, previous knee surgery, preoperative diagnosis, and ASA category were used. Kaplan-Meier estimated survival at 2 years was 98% (95% CI: 97.5-98.3) in the CON group and 96% (95% CI: 95.0-97.8) in the CAS group. The adjusted Cox regression analysis showed a higher risk of revision in the CAS group (RR = 1.7, 95% CI: 1.1-2.5; p = 0.02). The LCS Complete knee had a higher risk of revision with CAS than with CON (RR = 2.1, 95% CI: 1.3-3.4; p = 0.004)). The differences were not statistically significant for the other prosthesis brands. Mean operating time was 15 min longer in the CAS group. With the introduction of computer-navigated knee replacement surgery in Norway, the short-term risk of revision has increased for computer-navigated replacement with the LCS Complete. The mechanisms of failure of these implantations should be explored in greater depth, and in this study we have not been able to draw conclusions regarding causation.

  14. Compatibility of the totally replaced hip. Reduction of wear by amorphous diamond coating.

    PubMed

    Santavirta, Seppo

    2003-12-01

    Particulate wear debris in totally replaced hips causes adverse local host reactions. The extreme form of such a reaction, aggressive granulomatosis, was found to be a distinct condition and different from simple aseptic loosening. Reactive and adaptive tissues around the totally replaced hip were made of proliferation of local fibroblast like cells and activated macrophages. Methylmethacrylate and high-molecular-weight polyethylene were shown to be essentially immunologically inert implant materials, but in small particulate form functioned as cellular irritants initiating local biological reactions leading to loosening of the implants. Chromium-cobalt-molybdenum is the most popular metallic implant material; it is hard and tough, and the bearings of this metal are partially self-polishing. In total hip implants, prerequisites for longevity of the replaced hip are good biocompatibility of the materials and sufficient tribological properties of the bearings. The third key issue is that the bearing must minimize frictional shear at the prosthetic bone-implant interface to be compatible with long-term survival. Some of the approaches to meet these demands are alumina-on-alumina and metal-on-metal designs, as well as the use of highly crosslinked polyethylene for the acetabular component. In order to avoid the wear-based deleterious properties of the conventional total hip prosthesis materials or coatings, the present work included biological and tribological testing of amorphous diamond. Previous experiments had demonstrated that a high adhesion of tetrahedral amorphous carbon coatings to a substrate can be achieved by using mixing layers or interlayers. Amorphous diamond was found to be biologically inert, and simulator testing indicated excellent wear properties for conventional total hip prostheses, in which either the ball or both bearing surfaces were coated with hydrogen-free tetrahedral amorphous diamond films. Simulator testing with such total hip prostheses showed no measurable wear or detectable delamination after 15,000,000 test cycles corresponding to 15 years of clinical use. The present work clearly shows that wear is one of the basic problems with totally replaced hips. Diamond coating of the bearing surfaces appears to be an attractive solution to improve longevity of the totally replaced hip.

  15. [Total Joint Replacement and Return to Sports].

    PubMed

    Oehler, N; Schmidt, T; Niemeier, A

    2016-12-01

    Background: An increasing number of physically active patients not only need to know if they will basically be able to engage in sports after undergoing arthroplasty. They also would like to know whether or not they will be able to resume their preoperative activity levels. This article aims to provide an overview of recent data regarding the following questions on hip, knee and shoulder arthroplasty: (1) What is the impact of physical activity on an endoprosthesis? (2) What level of sports can be achieved after an arthroplasty procedure? (3) What types of sport are recommended for patients with an endoprosthesis? Methods: PubMed-based review of the literature. Narrative review focusing on current data from the years 2010 to 2016. Results: The commonly known recommendation to exercise low-impact sports such as hiking, swimming, cycling or golf at a moderate intensity remains valid for all types of prostheses in all joints. There is broad consensus that the benefits of these sports outweigh the negative effects. Having undergone total hip or knee arthroplasty, most patients with a high preoperative activity level return to sports after 3-6 months, albeit with a clear tendency to lower intensity and a shift from high-impact to low-impact sports. Some key questions have to be answered regarding the effects of low-impact sports that are exercised with high intensity, the effects resulting from high-impact sports, effects specific to different types of sport, and possibilities provided by different prosthesis types. In this context, a lot remains to be done to investigate the limits between positive and negative effects resulting from physical activity of varying intensity. New data suggests that generally a higher physical performance level may be achieved than has been traditionally recommended. Early results of unicondylar knee prostheses are far better than those achieved with bicondylar prostheses. In contrast to expert recommendations, shoulder endoprostheses show the highest postoperative activity levels after inverted arthroplasty, followed by anatomic arthroplasty, and the lowest activity level after the implantation of a hemiprosthesis. Conclusion: There is a significant discrepancy between previous expert recommendations and the actual activity levels that may be achieved after the implantation of a joint prosthesis. Future studies have to define the sports level, the type of sports and the type of prosthesis that provide a positive benefit-risk ratio using state-of-the-art low-abrasion bearing surfaces and prosthesis designs. © Georg Thieme Verlag KG Stuttgart · New York.

  16. Evaluation of an analytic linear Boltzmann transport equation solver for high-density inhomogeneities

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lloyd, S. A. M.; Ansbacher, W.; Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 3P6

    2013-01-15

    Purpose: Acuros external beam (Acuros XB) is a novel dose calculation algorithm implemented through the ECLIPSE treatment planning system. The algorithm finds a deterministic solution to the linear Boltzmann transport equation, the same equation commonly solved stochastically by Monte Carlo methods. This work is an evaluation of Acuros XB, by comparison with Monte Carlo, for dose calculation applications involving high-density materials. Existing non-Monte Carlo clinical dose calculation algorithms, such as the analytic anisotropic algorithm (AAA), do not accurately model dose perturbations due to increased electron scatter within high-density volumes. Methods: Acuros XB, AAA, and EGSnrc based Monte Carlo are usedmore » to calculate dose distributions from 18 MV and 6 MV photon beams delivered to a cubic water phantom containing a rectangular high density (4.0-8.0 g/cm{sup 3}) volume at its center. The algorithms are also used to recalculate a clinical prostate treatment plan involving a unilateral hip prosthesis, originally evaluated using AAA. These results are compared graphically and numerically using gamma-index analysis. Radio-chromic film measurements are presented to augment Monte Carlo and Acuros XB dose perturbation data. Results: Using a 2% and 1 mm gamma-analysis, between 91.3% and 96.8% of Acuros XB dose voxels containing greater than 50% the normalized dose were in agreement with Monte Carlo data for virtual phantoms involving 18 MV and 6 MV photons, stainless steel and titanium alloy implants and for on-axis and oblique field delivery. A similar gamma-analysis of AAA against Monte Carlo data showed between 80.8% and 87.3% agreement. Comparing Acuros XB and AAA evaluations of a clinical prostate patient plan involving a unilateral hip prosthesis, Acuros XB showed good overall agreement with Monte Carlo while AAA underestimated dose on the upstream medial surface of the prosthesis due to electron scatter from the high-density material. Film measurements support the dose perturbations demonstrated by Monte Carlo and Acuros XB data. Conclusions: Acuros XB is shown to perform as well as Monte Carlo methods and better than existing clinical algorithms for dose calculations involving high-density volumes.« less

  17. A Stereophotogrammetric System For The Detection Of Prosthesis Loosening In Total Hip Arthroplasty

    NASA Astrophysics Data System (ADS)

    Baumrind, Sheldon; Genant, Harry K.; Hunter, John; Miller, David; Moffitt, Francis; Murray, William R.; Ross, Steven E.

    1980-07-01

    Loosening of the prosthetic device occurs in about 5% of cases following placement of total hip prostheses (THP). Early detection of loosening is much desired but is difficult to achieve using conventional methods. Due to errors of projection, it is quite possible to fail to detect mobility of even as much as 5 mm on single x-ray films. We are attempting to develop a simplified photogrammetric system suitable for general hospital use which could detect loosening of 0.8 mm at the 95 % level of confidence without use of complex stereoplotting equipment. Metal reference markers are placed in the shaft of the femur and in the acetabular region of the pelvis at the time of surgery. The distances between these reference markers and certain unambiguous points on the prostheses are computed analytically using an X-Y acoustical digitizer (accuracy ± 0.1 mm) and software developed previously for craniofacial measurement. Separate stereopairs of the joint region are taken under weight-bearing and nonweight-bearing conditions. Differences in the measured distances between the bo-ne markers and the prosthetic components on the two stereopairs are taken as indicators of prosthesis loosening. Measurements on a phantom using ten different x-ray stereopairs taken from as many different perspectives have established that true linear distances between reference points and prostheses can be measured at the desired reliability with the present low precision system. Preliminary in vivo measurements indicate that the main unresolved problem is the movement of the subject between the two exposures of each single stereopair. Two possible solutions to this problem are discussed.

  18. The influence of acetabular bone cracks in the press-fit hip replacement: Numerical and experimental analysis.

    PubMed

    Ramos, A; Duarte, R J; Relvas, C; Completo, A; Simões, J A

    2013-07-01

    The press-fit hip acetabular prosthesis implantation can cause crack formation in the thin regions surrounding the acetabular. As a consequence the presence of cracks in this region can lead to poor fixation and fibrous tissue formation. Numerical and experimental models of commercial press-fit hip replacements were developed to compare the behavior between the intact and implanted joints. Numerical models with an artificial crack and without crack were considered. The iliac and the femur were created through 3D geometry acquisition based on composite human replicas and 3D-Finite Element models were generated. The mechanical behavior was assessed numerically and experimentally considering the principal strains. The comparison between Finite Element model predictions and experimental measurements revealed a maximum difference of 9%. Similar distribution of the principal strains around the acetabular cavity was obtained for the intact and implanted models. When comparing the Von Mises stresses, it is possible to observe that the intact model is the one that presents the highest stress values in the entire acetabular cavity surface. The crack in the posterior side changes significantly the principal strain distribution, suggesting bone loss after hip replacement. Relatively to micromotions, these were higher on the superior side of the acetabular cavity and can change the implant stability and bone ingrowth. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Computed Tomography Imaging of a Hip Prosthesis Using Iterative Model-Based Reconstruction and Orthopaedic Metal Artefact Reduction: A Quantitative Analysis.

    PubMed

    Wellenberg, Ruud H H; Boomsma, Martijn F; van Osch, Jochen A C; Vlassenbroek, Alain; Milles, Julien; Edens, Mireille A; Streekstra, Geert J; Slump, Cornelis H; Maas, Mario

    To quantify the combined use of iterative model-based reconstruction (IMR) and orthopaedic metal artefact reduction (O-MAR) in reducing metal artefacts and improving image quality in a total hip arthroplasty phantom. Scans acquired at several dose levels and kVps were reconstructed with filtered back-projection (FBP), iterative reconstruction (iDose) and IMR, with and without O-MAR. Computed tomography (CT) numbers, noise levels, signal-to-noise-ratios and contrast-to-noise-ratios were analysed. Iterative model-based reconstruction results in overall improved image quality compared to iDose and FBP (P < 0.001). Orthopaedic metal artefact reduction is most effective in reducing severe metal artefacts improving CT number accuracy by 50%, 60%, and 63% (P < 0.05) and reducing noise by 1%, 62%, and 85% (P < 0.001) whereas improving signal-to-noise-ratios by 27%, 47%, and 46% (P < 0.001) and contrast-to-noise-ratios by 16%, 25%, and 19% (P < 0.001) with FBP, iDose, and IMR, respectively. The combined use of IMR and O-MAR strongly improves overall image quality and strongly reduces metal artefacts in the CT imaging of a total hip arthroplasty phantom.

  20. Measurements of hip-bone distortions caused by the stress of inserted prosthesis by means of the speckle photography method

    NASA Astrophysics Data System (ADS)

    Gajda, Jerzy K.; Niesterowicz, Andrzej; Mazurkiewicz, Henryk

    1995-03-01

    A high number of osseous diseases, particularly of the backbone and hip-joint regions, result in a need for their overall treatment and prevention. Two basic treatment methods are used: physical exercises at an early stage of the illness, and surgical treatment in an advanced stage. Recently, in operational treatment of coxarthrosis the elements of the joint (acetabulum and capitellum) were replaced by their artificial counterparts, despite some drawbacks and unknowns related to this kind of treatment. In order to check the effectiveness of this treatment and to eliminate its drawbacks we have tested the joint by means of speckle photography method. The objective of this paper is an attempt to evaluate stress and displacement distributions in a system consisting of artificial acetabulum and capitellum and a natural bone in order to determine an optimum fitting of artificial acetabulum and capitellum and a natural bone in order to determine an optimum fitting of artificial elements that guarantees uniform distribution of stresses corresponding to anatomical and physiological parameters of the hip-joint. Speckle photographs have been analyzed point by point with the help of the algorithm for striped images processing.

  1. Long term survival of an hydroxyapatite-coated threaded cup in the presence of a high polythene wear rate.

    PubMed

    Datir, Sandeep P; Angus, Peter D

    2010-01-01

    We describe the long term clinical results and polythene wear rate measurement of 144 uncemented total hip arthroplasties in 118 patients (Male: Female-65: 53, Mean age: 52.8 years (range 21-78 years) performed between 1988 and 2000 using the Furlong HAC coated threaded acetabular cup. The mean follow-up for the group was 10.2 years (range: 5-17.5, median: 9.7). One femoral stem and two acetabular shells were revised due to aseptic loosening. The mean polythene wear rate was 0.24 mm/year. Ten-year survival for the acetabular and femoral components with radiological evidence of aseptic loosening as an end point was 99.15 (CI: 98.3-99.9) and 99.28 (CI: 98.5-99.9). There was no evidence of osteolysis around the femoral or acetabular components in spite of a relatively high polythene wear rate (0.24 mm/year). Our study demonstrates excellent survival of threaded HAC coated acetabular sockets at 10 years in spite of a relatively high polythene wear rate.

  2. Acinetobacter Prosthetic Joint Infection Treated with Debridement and High-Dose Tigecycline.

    PubMed

    Vila, Andrea; Pagella, Hugo; Amadio, Claudio; Leiva, Alejandro

    2016-12-01

    Prosthesis retention is not recommended for multidrug-resistant Acinetobacter prosthetic joint infection due to its high failure rate. Nevertheless, replacing the prosthesis implies high morbidity and prolonged hospitalization. Although tigecycline is not approved for the treatment of prosthetic joint infection due to multidrug resistant Acinetobacter baumannii, its appropriate use may preclude prosthesis exchange. Since the area under the curve divided by the minimum inhibitory concentration is the best pharmacodynamic predictor of its efficacy, we used tigecycline at high dose, in order to optimize its efficacy and achieve implant retention in 3 patients who refused prosthesis exchange. All patients with prosthetic joint infections treated at our Institution are prospectively registered in a database. Three patients with early prosthetic joint infection of total hip arthroplasty due to multidrug resistant A. baumannii were treated with debridement, antibiotics and implant retention, using a high maintenance dose of tigecycline (100 mg every 12 hours). The cases were retrospectively reviewed. All patients signed informed consent for receiving off-label use of tigecycline. Tigecycline was well tolerated, allowing its administration at high maintenance dose for a median of 40 days (range 30-60). Two patients were then switched to minocycline at standard doses for a median of 3.3 months in order to complete treatment. Currently, none of the patients showed relapse. Increasing the dose of tigecycline could be considered as a means to better attain pharmacodynamic targets in patients with severe or difficult-to-treat infections. Tigecycline at high maintenance dose might be useful when retention of the implant is attempted for treatment for prosthetic joint infections due to multidrug resistant Acinetobacter. Although this approach might be promising, off-label use of tigecycline should be interpreted cautiously until prospective data are available. Tigecycline is probably under-dosed for the treatment of implant and biofilm associated infections.

  3. Cemented tibial component fixation performs better than cementless fixation: a randomized radiostereometric study comparing porous-coated, hydroxyapatite-coated and cemented tibial components over 5 years.

    PubMed

    Carlsson, Ake; Björkman, Anders; Besjakov, Jack; Onsten, Ingemar

    2005-06-01

    The question whether the tibial component of a total knee arthroplasty should be fixed to bone with or without bone cement has not yet been definitely answered. We studied movements between the tibial component and bone by radiostereometry (RSA) in total knee replacement (TKR) for 3 different types of fixation: cemented fixation (C-F), uncemented porous fixation (UC-F) and uncemented porous hydroxyapatite fixation (UCHA-F). 116 patients with osteoarthrosis, who had 146 TKRs, were included in 2 randomized series. The first series included 86 unilateral TKRs stratified into 1 of the 3 types of fixation. The second series included 30 patients who had simultaneous bilateral TKR surgery, and who were stratified into 3 subgroups of pairwise comparisons of the 3 types of fixation. After 5 years 2 knees had been revised, neither of which were due to loosening. 1 UCHA-F knee in the unilateral series showed a large and continuous migration and a poor clinical result, and is a pending failure. The C-F knees rotated and migrated less than UC-F and UCHA-F knees over 5 years. UCHA-F migrated less than UC-F after 1 year. Cementing of the tibial component offers more stable bone-implant contact for 5 years compared to uncemented fixation. When using uncemented components, however, there is evidence that augmenting a porous surface with hydroxyapatite may mean less motion between implant and bone after the initial postoperative year.

  4. The efficiency of risedronate in reducing bone resorption after total hip arthroplasty: a meta-analysis of randomized control trials at a minimum of 6 months' follow-up.

    PubMed

    Yang, Liqing

    2018-04-17

    Recently risedronate is suggested to be effective for the prevention and treatment of for osteoporosis in total hip arthroplasty. This meta-analysis aimes to evaluate the efficacy of risedronate in reducing femoral periprosthetic bone mineral density loss in patients undergoing primary total hip arthroplasty. A systematic search was performed in Medline (1966-31 October 2017), PubMed (1966-31 October 2017), Embase (1980-31 October 2017), ScienceDirect (1985-31 October 2017) and the Cochrane Library. Only randomized controlled trial (RCT) were included. Fixed/random effect model was used according to the heterogeneity tested by I2 statistic. Meta-analysis was performed using Stata 11.0 software. The outcome measures included periprosthetic bone mineral density, length of stay and adverse effects. Four RCTs including 198 patients met the inclusion criteria. The present meta-analysis showed that there were significant differences between treatment groups in terms of periprosthetic bone mineral density in Gruen zones 1 (standard mean difference (SMD) = 0.758, 95% CI 0.469 to 1.047, P = 0.000), 2 (SMD = 0.814, 95% CI 0.523 to 1.106, P = 0.000), 3 (SMD = 0.340, 95% CI 0.059 to 0.622, P = 0.018), 6 (SMD = 2.400, 95% CI 2.029 to 2.771, P = 0.000), and 7 (SMD = 2.400, 95% CI 2.029 to 2.771, P = 0.000). Oral risedronate could significantly reduce periprosthetic bone resorption around an uncemented femoral stem (Gruen zones 1, 2, 3, 6, and 7) up to 6 months after THA. In addition, no severe adverse events were identified. Future trials of risedronate treatment after THA should focus on clinically relevant end points such as the risks of fracture and revision arthroplasty.

  5. The effect of cement on hip stem fixation: a biomechanical study.

    PubMed

    Çelik, Talip; Mutlu, İbrahim; Özkan, Arif; Kişioğlu, Yasin

    2017-06-01

    This study presents the numerical analysis of stem fixation in hip surgery using with/without cement methods since the use of cement is still controversial based on the clinical studies in the literature. Many different factors such as stress shielding, aseptic loosening, material properties of the stem, surgeon experiences etc. play an important role in the failure of the stem fixations. The stem fixation methods, cemented and uncemented, were evaluated in terms of mechanical failure aspects using computerized finite element method. For the modeling processes, three dimensional (3D) femur model was generated from computerized tomography (CT) images taken from a patient using the MIMICS Software. The design of the stem was also generated as 3D CAD model using the design parameters taken from the manufacturer catalogue. These 3D CAD models were generated and combined with/without cement considering the surgical procedure using SolidWorks program and then imported into ANSYS Workbench Software. Two different material properties, CoCrMo and Ti6Al4V, for the stem model and Poly Methyl Methacrylate (PMMA) for the cement were assigned. The material properties of the femur were described according to a density calculated from the CT images. Body weight and muscle forces were applied on the femur and the distal femur was fixed for the boundary conditions. The calculations of the stress distributions of the models including cement and relative movements of the contacts examined to evaluate the effects of the cement and different stem material usage on the failure of stem fixation. According to the results, the use of cement for the stem fixation reduces the stress shielding but increases the aseptic loosening depending on the cement crack formations. Additionally, using the stiffer material for the stem reduces the cement stress but increases the stress shielding. Based on the results obtained in the study, even when taking the disadvantages into account, the cement usage is more suitable for the hip fixations.

  6. Joint issues – conflicts of interest, the ASR hip and suggestions for managing surgical conflicts of interest

    PubMed Central

    2014-01-01

    Background Financial and nonfinancial conflicts of interest in medicine and surgery are troubling because they have the capacity to skew decision making in ways that might be detrimental to patient care and well-being. The recent case of the Articular Surface Replacement (ASR) hip provides a vivid illustration of the harmful effects of conflicts of interest in surgery. Discussion We identify financial and nonfinancial conflicts of interest experienced by surgeons, hospitals and regulators in the ASR case. These conflicts may have impacted surgical advice, decision-making and evidence gathering with respect to the ASR prosthesis, and contributed to the significant harms experienced by patients in whom the hip was implanted. Drawing on this case we explore shortcomings in the standard responses to conflicts of interest – disclosure and recusal. We argue disclosure is necessary but by no means sufficient to address conflicts of interest. Using the concept of recusal we develop remedies including second opinions and third party consent which may be effective in mitigating conflicts, but their implementation introduces new challenges. Summary Deployment of the ASR hip is a case of surgical innovation gone wrong. As we show, there were multiple conflicts of interest involved in the introduction of the ASR hip into practice and subsequent attempts to gloss over the mounting body of evidence about its lack of safety and effectiveness. Conflicts of interest in surgery are often not well managed. We suggest strategies in this paper which can minimise the conflicts of interest associated with surgical innovation. PMID:25128372

  7. Better early functional outcome after short stem total hip arthroplasty? A prospective blinded randomised controlled multicentre trial comparing the Collum Femoris Preserving stem with a Zweymuller straight cementless stem total hip replacement for the treatment of primary osteoarthritis of the hip

    PubMed Central

    van Oldenrijk, Jakob; Scholtes, Vanessa A B; van Beers, Loes W A H; Geerdink, Carel H; Niers, Bob B A M; Runne, Wouter; Bhandari, Mohit; Poolman, Rudolf W

    2017-01-01

    Objectives Primary aim was to compare the functional results at 3 months and 2 years between short and conventional cementless stem total hip arthroplasty (THA). Secondary aim was to determine the feasibility of a double-blind implant-related trial. Design A prospective blinded randomised controlled multicentre trial in patients with osteoarthritis of the hip. All patients, research assistants, clinical assessors, investigators and data analysts were blinded to the type of prosthesis. Population: 150 patients between 18 and 70 years with osteoarthritis of the hip, 75 in the short stem and 75 in the conventional stem group. Mean age: 60 years (SD 7). Interventions: the Collum Femoris Preserving short stem versus the Zweymuller Alloclassic conventional stem. Main outcome measures The Dutch version of the Hip Disability and Osteoarthritis Outcome Score (HOOS). Secondary outcomes measures: Harris Hip Score, the Physical Component Scale of the SF12, the Timed Up and Go test, Pain and the EQ-5D. Feasibility outcomes: continued blinding, protocol adherence and follow-up success rate. Results No significant difference between the two groups. Mean HOOS total score in the short stem group increased 32.7 points from 36.6 (95% CI 32.9 to 40.2) preoperatively to 69.3 (95% CI 66.4 to 72.1) at 3 months follow-up. Mean HOOS total score in the conventional straight stem group increased 36.3 points from 37.1 (95% CI 33.9 to 40.3) preoperatively to 73.4 (95% CI 70.3 to 76.4) at 3 months follow-up. 91.2% of patients remained blinded at 2 years follow-up. Both protocol adherence and follow-up success rate were 98%. Conclusions Functional result at 3 months and 2 years after short stem THA is not superior to conventional cementless THA. There were more perioperative and postoperative complications in the short stem group. Direct comparison of two hip implants in a double-blinded randomised controlled trial is feasible. Trial registration number NTR1560. PMID:29042371

  8. A sex-specific association between incident radiographic osteoarthritis of hip or knee and incident peripheral arterial calcifications: 8-year prospective data from Cohort Hip and Cohort Knee (CHECK).

    PubMed

    Gielis, W P; Welsing, P M J; van Spil, W E; Runhaar, J; Weinans, H; de Jong, P A

    2017-11-01

    There is sparse evidence for a relationship between cardiovascular disease (CVD) and osteoarthritis (OA). We investigated the association between incidence of arterial calcifications and incidence of radiographic knee and/or hip OA. We used baseline and 8-year follow-up data of Cohort Hip and Cohort Knee (CHECK). Knees and hips were either Kellgren-Lawrence (KL) grade 0 or 1 at baseline. Arterial calcifications were scored on hip and knee radiographs using a four-grade scale. Scores were summed for patient-level analyses. To investigate incidence, participants with arterial calcifications at baseline or missing follow-up were excluded. Incident OA was defined per joint as KL ≥ 2 or prosthesis at year eight. The association between incidenct of arterial calcifications and incident OA was studied using mixed-effects logistic regression. Of 763 participants included, 623 (82%) were women. Mean (sd) age was 56 (5.1) years, mean (sd) body mass index (BMI) 26.2 (4.1) kg/m 2 . Arterial calcifications developed in 174 participants (283 joints). OA developed in 456 participants (778 joints). Sex modified the association between arterial calcification and OA. In women, incident arterial calcification around a joint was positively associated with incident OA in that joint (adjusted OR 2.51 (95% CI 1.57-4.03)). In men, no association was observed on joint-level, but at patient-level the arterial calcification sum score was negatively associated with incident OA (adjusted OR per point increase 0.70 (95% CI 0.54-0.90)) indicating a systemic effect. We observed sex-dependent associations between incident arterial calcification and incident radiographic knee and/or hip OA, which differs between joint- and patient-level. Copyright © 2017 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  9. Tribocorrosion behavior of CoCrMo alloy for hip prosthesis as a function of loads: a comparison between two testing systems

    PubMed Central

    Mathew, M.T.; Runa, M.J.; Laurent, M.; Jacobs, J.J.; Rocha, L.A.; Wimmer, M.A.

    2011-01-01

    Metal-on-metal (MOM) hip prosthesis bearings have enjoyed renewed popularity, but concerns remain with wear debris and metal ion release causing a negative response in the surrounding tissues. Further understanding into the wear and corrosion mechanisms occurring in MOM hips is therefore essential. The purpose of this study was to evaluate the tribocorrosion behaviour, or interplay between corrosion and wear, of a low-carbon CoCrMo alloy as a function of loading. The tribocorrosion tests were performed using two tribometer configurations. In the first configuration, “System A”, a linearly reciprocating alumina ball slid against the flat metal immersed in a phosphate buffer solution (PBS). In the second configuration, “System B”, the flat end of a cylindrical metal pin was pressed against an alumina ball that oscillated rotationally, using bovine calf serum (BCS) as the lubricant and electrolyte. System B was custom-built to emulate in vivo conditions. The tribocorrosion tests were performed under potentiostatic conditions at -0.345V, with a sliding duration of 1800 seconds and a frequency of 1Hz. In System A the applied loads were 0.05, 0.5, and 1N (138, 296 and 373MPa, respectively) and in System B were 16, 32, and 64N (474, 597, and 752MPa, respectively). Electrochemical impedance spectroscopy (EIS) and polarization resistance were estimated. The total mass loss (Kwc) in the CoCrMo was determined. The mass loss due to wear (Kw) and that due to corrosion (Kc) were determined. The dominant wear regime for the CoCrMo alloy subjected to sliding changes from wear-corrosion to mechanical wear as the contact stress increases. An attempt was made to compare both system, in their tribochemical responses and formulate some insights in the total degradation processes. Our results also suggest that the proteins in the serum lubricant assist in the generation of a protective layer against corrosion during sliding. The study highlights the need of adequate methodology/guidelines to compare the results from different test systems and translating in solving the practical problems. PMID:21921971

  10. Peri-apatite coating decreases uncemented tibial component migration: long-term RSA results of a randomized controlled trial and limitations of short-term results.

    PubMed

    Van Hamersveld, Koen T; Marang-Van De Mheen, Perla J; Nelissen, Rob G H H; Toksvig-Larsen, Sören

    2018-05-09

    Background and purpose - Biological fixation of uncemented knee prostheses can be improved by applying hydroxyapatite coating around the porous surface via a solution deposition technique called Peri-Apatite (PA). The 2-year results of a randomized controlled trial, evaluating the effect of PA, revealed several components with continuous migration in the second postoperative year, particularly in the uncoated group. To evaluate whether absence of early stabilization is diagnostic of loosening, we now present long-term follow-up results. Patients and methods - 60 patients were randomized to PA-coated or uncoated (porous only) total knee arthroplasty of which 58 were evaluated with radiostereometric analysis (RSA) performed at baseline, at 3 months postoperatively and at 1, 2, 5, 7, and 10 years. A linear mixed-effects model was used to analyze the repeated measurements. Results - PA-coated components had a statistically significantly lower mean migration at 10 years of 0.94 mm (95% CI 0.72-1.2) compared with the uncoated group showing a mean migration of 1.72 mm (95% CI 1.4-2.1). Continuous migration in the second postoperative year was seen in 7 uncoated components and in 1 PA-coated component. All of these implants stabilized after 2 years except for 2 uncoated components. Interpretation - Peri-apatite enhances stabilization of uncemented components. The number of components that stabilized after 2 years emphasizes the importance of longer follow-up to determine full stabilization and risk of loosening in uncemented components with biphasic migration profiles.

  11. Prolonged incubation time does not increase sensitivity for the diagnosis of implant-related infection using samples prepared by sonication of the implants.

    PubMed

    Esteban, J; Alvarez-Alvarez, B; Blanco, A; Fernández-Roblas, R; Gadea, I; Garcia-Cañete, J; Sandoval, E; Valdazo, M

    2013-07-01

    We have designed a prospective study to evaluate the usefulness of prolonged incubation of cultures from sonicated orthopaedic implants. During the study period 124 implants from 113 patients were processed (22 osteosynthetic implants, 46 hip prostheses, 54 knee prostheses, and two shoulder prostheses). Of these, 70 patients had clinical infection; 32 had received antibiotics at least seven days before removal of the implant. A total of 54 patients had sonicated samples that produced positive cultures (including four patients without infection). All of them were positive in the first seven days of incubation. No differences were found regarding previous antibiotic treatment when analysing colony counts or days of incubation in the case of a positive result. In our experience, extending incubation of the samples to 14 days does not add more positive results for sonicated orthopaedic implants (hip and knee prosthesis and osteosynthesis implants) compared with a conventional seven-day incubation period.

  12. Early failure mechanisms of constrained tripolar acetabular sockets used in revision total hip arthroplasty.

    PubMed

    Cooke, Christopher C; Hozack, William; Lavernia, Carlos; Sharkey, Peter; Shastri, Shani; Rothman, Richard H

    2003-10-01

    Fifty-eight patients received an Osteonics constrained acetabular implant for recurrent instability (46), girdlestone reimplant (8), correction of leg lengthening (3), and periprosthetic fracture (1). The constrained liner was inserted into a cementless shell (49), cemented into a pre-existing cementless shell (6), cemented into a cage (2), and cemented directly into the acetabular bone (1). Eight patients (13.8%) required reoperation for failure of the constrained implant. Type I failure (bone-prosthesis interface) occurred in 3 cases. Two cementless shells became loose, and in 1 patient, the constrained liner was cemented into an acetabular cage, which then failed by pivoting laterally about the superior fixation screws. Type II failure (liner locking mechanism) occurred in 2 cases. Type III failure (femoral head locking mechanism) occurred in 3 patients. Seven of the 8 failures occurred in patients with recurrent instability. Constrained liners are an effective method for treatment during revision total hip arthroplasty but should be used in select cases only.

  13. Microstructural characterization of low and high carbon CoCrMo alloy nanoparticles produced by mechanical milling

    NASA Astrophysics Data System (ADS)

    Simoes, T. A.; Goode, A. E.; Porter, A. E.; Ryan, M. P.; Milne, S. J.; Brown, A. P.; Brydson, R. M. D.

    2014-06-01

    CoCrMo alloys are utilised as the main material in hip prostheses. The link between this type of hip prosthesis and chronic pain remains unclear. Studies suggest that wear debris generated in-vivo may be related to post-operative complications such as inflammation. These alloys can contain different amounts of carbon, which improves the mechanical properties of the alloy. However, the formation of carbides could become sites that initiate corrosion, releasing ions and/or particles into the human body. This study analysed the mechanical milling of alloys containing both high and low carbon levels in relevant biological media, as an alternative route to generate wear debris. The results show that low carbon alloys produce significantly more nanoparticles than high carbon alloys. During the milling process, strain induces an fcc to hcp phase transformation. Evidence for cobalt and molybdenum dissolution in the presence of serum was confirmed by ICP-MS and TEM EDX techniques.

  14. Comparison of a low-pressure and a high-pressure pulsatile lavage during débridement for orthopaedic implant infection.

    PubMed

    Muñoz-Mahamud, E; García, S; Bori, G; Martínez-Pastor, J C; Zumbado, J A; Riba, J; Mensa, J; Soriano, A

    2011-09-01

    The aim of our study was to compare the effectiveness of high-pressure pulsatile lavage and low-pressure lavage in patients with an orthopaedic implant infection treated with open débridement followed by antibiotic treatment. Patients with an orthopaedic implant infection requiring open débridement from January 2008 to August 2009 were randomized prospectively to a low-pressure or a high-pressure pulsatile lavage arm. Relevant information about demographics, co-morbidity, type of implant, microbiology data, surgical treatment, and outcome were recorded. Comparison of proportions was made using χ(2) test or Fisher exact test when necessary. The Kaplan-Meier survival method was used to estimate the cumulative probability of treatment failure from open débridement to the last visit. Seventy-nine patients were included. There were no differences between the main characteristics between both groups (p > 0.05). Mean (SD) age of the whole cohort was 70.2 (11.9) years. There were 46 infections on knee prosthesis, 17 on hip prosthesis, 7 on hip hemiarthroplasties and 9 on osteosynthesis devices. There were 69 acute post-surgical infections, 8 acute haematogenous infections and 2 chronic infections. The most common microorganisms isolated were coagulase-negative Staphylococci in 34 cases, Staphylococcus aureus in 26 and Escherichia coli in 19 cases. There were 30 polymicrobial infections. A total of 42 and 37 patients were randomized to a high-pressure pulsatile or a low-pressure lavage, respectively. There was no difference in the success rate between both arms (80.9 vs. 86.5%, p = 0.56). The use of a high-pressure pulsatile lavage during open débridement of implant infections had a similar success rate as a low-pressure lavage.

  15. HEMIARTHROPLASTY IN THE TREATMENT FRACTURES OF THE FEMORAL NECK

    PubMed Central

    Ono, Nelson Keiske; de Andrade Lima, Guilherme Didier; Honda, Emerson Kiyoshi; Polesello, Giancarlo Cavalli; Guimarães, Rodrigo Pereira; Júnior, Walter Ricioli; de Queiroz, Marcelo Cavalheiro

    2015-01-01

    Objective: To epidemiologically and clinically evaluate patients with displaced femoral neck fractures that were surgically treatment with cemented hip hemiarthroplasty. Methods: All patients with displaced femoral neck fractures (Garden III and IV) who underwent cemented hip hemiarthroplasty using a unipolar prosthesis (Thompson), by means of a posterolateral access between June 2005 and September 2008 were retrospectively evaluated. Results: Seventy patients were initially evaluated. Their mean age was 83.1 years. The patients were predominantly female (84.3%). Thirty-six patients were monitored as outpatients for periods ranging from 10 to 48 months (mean of 26.5 months). Fifteen patients were lost to follow-up. Nineteen patients died, and the mortality rate within the first year was 25.4%. Patients classified as ASA III had a mortality rate of 25.7% and ASA II patients, a rate of 12.1%. Two patients had symptomatic deep vein thrombosis; one patient had an operative wound infection; and none of the patients presented hip dislocation. Most of the patients did not experience pain. Twelve patients (33%) showed deterioration of their walking ability. Conclusion: There were no cases of hip dislocation. Patients classified as ASA III had a higher mortality rate than did patients with ASA I or II. There was a worsening of walking ability in 33% of the patients. No revision due to loosening or pain was needed for any patient. Thirty patients did not present any pain (83.3%), four presented moderate pain (11.1%) and two presented intense pain (5.5%). PMID:27022567

  16. Biomechanical Evaluation of All-Polyethylene Pegged Bony Ingrowth Glenoid Fixation Techniques on Implant Micromotion.

    PubMed

    Wiater, Brett P; Moravek, James E; Kurdziel, Michael D; Baker, Kevin C; Wiater, J Michael

    2016-01-01

    Newer glenoid components that allow for hybrid cement fixation via traditional cementation of peripheral pegs and bony ingrowth into an interference-fit central peg introduce the possibility of long-term biological fixation. However, little biomechanical work has been done on the initial stability of these components and the various fixation options. We conducted a study in which all-polyethylene glenoid components with a centrally fluted peg were implanted in polyurethane blocks with interference-fit, hybrid cement, and fully cemented fixation (5 per fixation group). Biomechanical evaluation of glenoid loosening, according to ASTM Standard F-2028-12, subjected the glenoids to 50,000 cycles of rim loading, and glenoid component motion was recorded with 2 differential variable reluctance transducers fixed to each glenoid prosthesis. Fully cemented fixation exhibited significantly less mean distraction in comparison with interference-fit fixation (P < .001) and hybrid cement fixation (P < .001). Hybrid cement fixation exhibited significantly less distraction (P < .001), more compression (P < .001), and no significant difference in glenoid translation (P = .793) in comparison with interference-fit fixation. Fully cemented fixation exhibited the most resistance to glenoid motion in comparison with hybrid cement fixation and interference-fit fixation. However, hybrid cement fixation and interference-fit fixation exhibited equivocal motion. Given these results, cementation of peripheral pegs may confer no additional initial stability over that provided by uncemented interference-fit fixation.

  17. Safety and function of a prototype microprocessor-controlled knee prosthesis for low active transfemoral amputees switching from a mechanic knee prosthesis: a pilot study.

    PubMed

    Hasenoehrl, Timothy; Schmalz, Thomas; Windhager, Reinhard; Domayer, Stephan; Dana, Sara; Ambrozy, Clemens; Palma, Stefano; Crevenna, Richard

    2018-02-01

    Aim of this pilot study was to assess safety and functioning of a microprocessor-controlled knee prosthesis (MPK) after a short familiarization time and no structured physical therapy. Five elderly, low-active transfemoral amputees who were fitted with a standard non-microprocessor controlled knee prosthesis (NMPK) performed a baseline measurement consisting of a 3 D gait analysis, functional tests and questionnaires. The first follow-up consisted of the same test procedure and was performed with the MPK after 4 to 6 weeks of familiarization. After being refitted to their standard NMPK again, the subjects undertook the second follow-up which consisted of solely questionnaires 4 weeks later. Questionnaires and functional tests showed an increase in the perception of safety. Moreover, gait analysis revealed more physiologic knee and hip extension/flexion patterns when using the MPK. Our results showed that although the Genium with Cenior-Leg ruleset-MPK (GCL-MPK) might help to improve several safety-related outcomes as well as gait biomechanics the functional potential of the GCL-MPK may have been limited without specific training and a sufficient acclimation period. Implications for Rehabilitation Elderly transfemoral amputees are often limited in their activity by safety issues as well as insufficient functioning regarding the non microprocessor-controlled knee prostheses (NMPK), thing that could be eliminated with the use of suitable microprocessor-controlled prostheses (MPK). The safety and functioning of a prototype MPK (GCL-MPK) specifically designed for the needs of older and low-active transfemoral amputees was assessed in this pilot study. The GCL-MPK showed indicators of increased safety and more natural walking patterns in older and low-active transfemoral amputees in comparison to the standard NMPK already after a short acclimatisation time and no structured physical therapy. Regarding functional performance it seems as if providing older and low-active transfemoral amputees with the GCL-MPK alone without prescribing structured prosthesis training might be insufficient to achieve improvements over the standard NMPKs.

  18. The accuracy and precision of radiostereometric analysis in upper limb arthroplasty.

    PubMed

    Ten Brinke, Bart; Beumer, Annechien; Koenraadt, Koen L M; Eygendaal, Denise; Kraan, Gerald A; Mathijssen, Nina M C

    2017-06-01

    Background and purpose - Radiostereometric analysis (RSA) is an accurate method for measurement of early migration of implants. Since a relation has been shown between early migration and future loosening of total knee and hip prostheses, RSA plays an important role in the development and evaluation of prostheses. However, there have been few RSA studies of the upper limb, and the value of RSA of the upper limb is not yet clear. We therefore performed a systematic review to investigate the accuracy and precision of RSA of the upper limb. Patients and methods - PRISMA guidelines were followed and the protocol for this review was published online at PROSPERO under registration number CRD42016042014. A systematic search of the literature was performed in the databases Embase, Medline, Cochrane, Web of Science, Scopus, Cinahl, and Google Scholar on April 25, 2015 based on the keywords radiostereometric analysis, shoulder prosthesis, elbow prosthesis, wrist prosthesis, trapeziometacarpal joint prosthesis, humerus, ulna, radius, carpus. Articles concerning RSA for the analysis of early migration of prostheses of the upper limb were included. Quality assessment was performed using the MINORS score, Downs and Black checklist, and the ISO RSA Results - 23 studies were included. Precision values were in the 0.06-0.88 mm and 0.05-10.7° range for the shoulder, the 0.05-0.34 mm and 0.16-0.76° range for the elbow, and the 0.16-1.83 mm and 11-124° range for the TMC joint. Accuracy data from marker- and model-based RSA were not reported in the studies included. Interpretation - RSA is a highly precise method for measurement of early migration of orthopedic implants in the upper limb. However, the precision of rotation measurement is poor in some components. Challenges with RSA in the upper limb include the symmetrical shape of prostheses and the limited size of surrounding bone, leading to over-projection of the markers by the prosthesis. We recommend higher adherence to RSA guidelines and encourage investigators to publish long-term follow-up RSA studies.

  19. The impact of proximal femoral morphology on failure strength with a mid-head resection short-stem hip arthroplasty.

    PubMed

    Olsen, Michael; Al Saied, Mohamed; Morison, Zachary; Sellan, Michael; Waddell, James P; Schemitsch, Emil H

    2014-12-01

    Mid-head resection short-stem hip arthroplasty is a conservative alternative to conventional total hip replacement and addresses proximal fixation challenges in patients not suitable for hip resurfacing. It is unclear whether proximal femoral morphology impacts the ultimate failure load of mid-head resection implanted femurs, thus the aim of this study was to investigate the effect of native neck-shaft angle (NSA) and coronal implant alignment on proximal femoral strength. In total, 36 synthetic femurs with two different proximal femoral morphologies were utilized in this study. Of them, 18 femurs with a varus NSA of 120° and 18 femurs with a valgus NSA of 135° were each implanted with a mid-head resection prosthesis. Femurs within the two different femoral morphology groups were divided into three equal coronal implant alignment groups: 10° valgus, 10° varus or neutral alignment. Prepared femurs were tested for stiffness and to failure in axial compression. There was no significant difference in stiffness nor failure load between femurs implanted with valgus-, varus- or neutrally aligned implants in femurs with a NSA of 120° (p = 0.396, p = 0.111, respectively). Femurs implanted in valgus orientation were significantly stiffer and failed at significantly higher loads than those implanted in varus alignment in femurs with a NSA of 135° (p = 0.001, p = 0.007, respectively). A mid-head resection short-stem hip arthroplasty seems less sensitive to clinically relevant variations of coronal implant alignment and may be more forgiving upon implantation in some femoral morphologies, however, a relative valgus component alignment is recommended. © IMechE 2014.

  20. Have cementless and resurfacing components improved the medium-term results of hip replacement for patients under 60 years of age?

    PubMed Central

    Mason, James; Baker, Paul; Gregg, Paul J; Porter, Martyn; Deehan, David J; Reed, Mike R

    2015-01-01

    Background and purpose The optimal hip replacement for young patients remains unknown. We compared patient-reported outcome measures (PROMs), revision risk, and implant costs over a range of hip replacements. Methods We included hip replacements for osteoarthritis in patients under 60 years of age performed between 2003 and 2010 using the commonest brand of cemented, cementless, hybrid, or resurfacing prosthesis (11,622 women and 13,087 men). The reference implant comprised a cemented stem with a conventional polyethylene cemented cup and a standard-sized head (28- or 32-mm). Differences in implant survival were assessed using competing-risks models, adjusted for known prognostic influences. Analysis of covariance was used to assess improvement in PROMs (Oxford hip score (OHS) and EQ5D index) in 2014 linked procedures. Results In males, PROMs and implant survival were similar across all types of implants. In females, revision was statistically significantly higher in hard-bearing and/or small-stem cementless implants (hazard ratio (HR) = 4) and resurfacings (small head sizes (< 48 mm): HR = 6; large head sizes (≥ 48 mm): HR = 5) when compared to the reference cemented implant. In component combinations with equivalent survival, women reported significantly greater improvements in OHS with hybrid implants (22, p = 0.006) and cementless implants (21, p = 0.03) (reference, 18), but similar EQ5D index. For men and women, National Health Service (NHS) costs were lowest with the reference implant and highest with a hard-bearing cementless replacement. Interpretation In young women, hybrids offer a balance of good early functional improvement and low revision risk. Fully cementless and resurfacing components are more costly and do not provide any additional benefit for younger patients. PMID:25285617

  1. Clinical Cold Welding of the Modular Total Hip Arthroplasty Prosthesis.

    PubMed

    Whittaker, Robert K; Zaghloul, Ahmed M; Hothi, Harry S; Siddiqui, Imran A; Blunn, Gordon W; Skinner, John A; Hart, Alister J

    2017-02-01

    A head that is "clinically cold welded" to a stem is one of the commonest reasons for unplanned removal of the stem. It is not clear which hip designs are at greatest risk of clinical cold welding. This was a case-control study of consecutively received hip implant retrievals; we chose the design of hip that had the greatest number of truly cold-welded heads (n = 11). For our controls, we chose retrieved hips of the same design but without cold welding of the head (n = 35). We compared the clinical variables between these 2 groups using nonparametric Mann-Whitney tests to investigate the significance of differences between the cold-welded and non-cold-welded groups. The design that most commonly caused cold welding was a combination of a Ti stem and Ti taper: 11 out of 48 (23%) were truly cold welded. Comparison of the clinical data showed that no individual factor could be used to predict this preoperatively with none of the 4 predictors tested showing any significance: (1) time to revision (P = .687), (2) head size (P = .067), (3) patient age at primary (P = .380), and (4) gender (P = .054). We have shown that clinical cold welding is most prevalent in Ti-Ti combinations of the stem and taper; approximately 25% of cases received at our center were cold welded. Analysis of clinical variables showed that it is not possible to predict which will be cold welded preoperatively. Surgeons should be aware of this potential complication when revising a Ti-Ti stem/head junction. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Hierarchical structure and importance of patients' reasons for treatment choices in knee and hip osteoarthritis: a concept mapping study.

    PubMed

    Selten, Ellen M H; Geenen, Rinie; van der Laan, Willemijn H; van der Meulen-Dilling, Roelien G; Schers, Henk J; Nijhof, Marc W; van den Ende, Cornelia H M; Vriezekolk, Johanna E

    2017-02-01

    To improve patients' use of conservative treatment options of hip and knee OA, in-depth understanding of reasons underlying patients' treatment choices is required. The current study adopted a concept mapping method to thematically structure and prioritize reasons for treatment choice in knee and hip OA from a patients' perspective. Multiple reasons for treatment choices were previously identified using in-depth interviews. In consensus meetings, experts derived 51 representative reasons from the interviews. Thirty-six patients individually sorted the 51 reasons in two card-sorting tasks: one based on content similarity, and one based on importance of reasons. The individual sortings of the first card-sorting task provided input for a hierarchical cluster analysis (squared Euclidian distances, Ward's method). The importance of the reasons and clusters were examined using descriptive statistics. The hierarchical structure of reasons for treatment choices showed a core distinction between two categories of clusters: barriers [subdivided into context (e.g. the healthcare system) and disadvantages] and outcome (subdivided into treatment and personal life). At the lowest level, 15 clusters were identified of which the clusters Physical functioning, Risks and Prosthesis were considered most important when making a treatment decision for hip or knee OA. Patients' treatment choices in knee and hip OA are guided by contextual barriers, disadvantages of the treatment, outcomes of the treatment and consequences for personal life. The structured overview of reasons can be used to support shared decision-making. © The Author 2016. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. A finite element analysis of the vibrational behaviour of the intra-operatively manufactured prosthesis-femur system.

    PubMed

    Pastrav, L C; Devos, J; Van der Perre, G; Jaecques, S V N

    2009-05-01

    In total hip replacement (THR) a good initial stability of the prosthetic stem in the femur, which corresponds to a good overall initial contact, will help assure a good long-term result. During the insertion the implant stability increases and, as a consequence, the resonance frequencies increase, allowing the assessment of the implant fixation by vibration analysis. The influence of changing contact conditions on the resonance frequencies was however not yet quantitatively understood and therefore a finite element analysis (FEA) was set up. Modal analyses on the hip stem-femur system were performed in various contact situations. By modelling the contact changes by means of the contact tolerance options in the finite element software, contact could be varied over the entire hip stem surface or only in specific zones (proximal, central, distal) while keeping other system parameters constant. The results are in agreement with previous observations: contact increase causes positive resonance frequency shifts and the dynamic behaviour is most influenced by contact changes in the proximal zone. Although the finite element analysis did not establish a monotonous relationship between the vibrational mode number and the magnitude of the resonance frequency shift, in general the higher modes are more sensitive to the contact change.

  4. Different thermal conductivity in drilling of cemented compared with cementless hip prostheses in the treatment of periprosthetic fractures of the proximal femur: an experimental biomechanical analysis.

    PubMed

    Brand, Stephan; Klotz, Johannes; Hassel, Thomas; Petri, Maximilian; Ettinger, Max; Krettek, Christian; Goesling, Thomas; Bach, Friedrich-Wilhelm

    2013-10-01

    The purpose of this study was to evaluate the different temperature levels whilst drilling cemented and cementless hip prostheses implanted in bovine femora, and to evaluate the insulating function of the cement layer. Standard hip prostheses were implanted in bovine donor diaphyses, with or without a cement layer. Drilling was then performed using high-performance-cutting drills with a reinforced core, a drilling diameter of 5.5 mm and cooling channels through the tip of the drill for constantly applied internal cooling solution. An open type cooling model was used in this setup. Temperature was continuously measured by seven thermocouples placed around the borehole. Thermographic scans were also performed during drilling. At the cemented implant surface, the temperature never surpassed 24.7 °C when constantly applied internal cooling was used. Without the insulating cement layer (i.e. during drilling of the cementless bone-prosthesis construct), the temperature increased to 47 °C. Constantly applied internal cooling can avoid structural bone and soft tissue damage during drilling procedures. With a cement layer, the temperatures only increased to non-damaging levels. The results could be useful in the treatment of periprosthetic fractures with intraprosthetic implant fixation.

  5. Computer tomography prototyping and virtual procedure simulation in difficult cases of hip replacement surgery.

    PubMed

    Parchi, Paolo Domenico; Ferrari, Vincenzo; Piolanti, Nicola; Andreani, Lorenzo; Condino, Sara; Evangelisti, Gisberto; Lisanti, Michele

    2013-09-01

    Each year approximately 1 million total hip replacements (THR) are performed worldwide. A percentage of failure due to surgical approach and imprecise implant placement still exists. These result in several serious complications. We propose an approach to plan, to simulate, and to assist prosthesis implantation for difficult cases of THR based on 3-D virtual models, generated by segmenting patients' CT images, 3-D solid models, obtained by rapid prototyping (RP), and virtual procedure simulation. We carried out 8 THR with the aid of 3-D reconstruction and RP. After each procedure a questionnaire was submitted to the surgeon to assess the perceived added value of the technology. In all cases, the surgeon evaluated the 3-D model as useful in order to perform the planning. The clinical results showed a mean increase in the Harris Hip Score of about 42.5 points. The mean time of prototyping was 7.3 hours, (min 3.5 hours, max 9.3 hours). The mean surgery time was 65 minutes (min 50 minutes, max 88 minutes). Our study suggests that meticulous preoperative planning is necessary in front of a great aberration of the joint and in absence of normal anatomical landmarks, CT scan is mandatory, and 3-D reconstruction with solid model is useful.

  6. [A therapeutic effect analysis of femur first principle and combined anteversion technique during total hip arthroplasty].

    PubMed

    Wang, X Q; Wu, C S; Sun, S; Wang, J; Li, W; Zhang, W

    2018-04-01

    Objective: To investigate the situation of hip dislocation with the application of "femur first" principle and "combined anteversion technique" during total hip arthroplasty. Methods: A retrospective analysis has been done on the clinical data about 104 patients(133 hips)who were diagnosed as hip disease and were treated with total hip arthroplasty by the doctors from the Department of Joint Orthorpaedics of Shandong Provincial Hospital Affiliated to Shandong University from June 2014 to June 2016, and all the prostheses applied in the operation were cementless ones.Among them, 65 patients were males, 39 females and their age was 46.6 years (ranging from 23 to 76 years) .And 29 of them underwent bilateral hip operations and 75 unilateral ones.Seventy-six cases of aseptic necrosis of the femoral head in the terminal stage, 28 cases of hip dysplasia and osteoarthritis.Surgical approach: of all the operations, 103 hips were operated on with hardinge approach, 30 with posterolateral approach.During the operation, first of all, the femoral medullary cavity was broached and then the anteversion of intramedullary broacher was measured.After that, the anteversion of the acetabular cup was calculated as 37° minus the anteversion of the broacher, and the acetabular cup was implanted at that angle.The patients' prosthesis combined anteversion, range of motion of the hip joint, operation time, hemorrhage amount, and complications had been kept record.One, three, and six months respectively after the operation, all the patients received outpatient review, and took anteroposterior and lateral position X-ray examination.Harris hip score had been applied to evaluate their hip function before the operation and six months after the operation. Results: All the patients had been operated on smoothly, with the operation time of(57.6±14.5)minutes(36-115 minutes)and hemorrhage amount of (336.5±50.8)ml(180-620 ml). The operation finding showed that the combined anteversion by employing"femur first"principle and combined anteversion techniqueis was (36.6±6.8)°. Also, range of motion of the patients' hip conforms to the D'Lima criterion and no patients had experienced dislocation and some other serious complications.The follow-up ended at August 2017, which lasted for 12.2 months(6-18 months), and 88 cases(119 hips) were interviewed. The Harris hip score for the affected sides of the hip joints 6 months after the surgery was 94.6(86-100). Compared with the score of 29.8(12-43) before surgery, the t -test had proven its statistical significance( t =12.82, P =0.003). Conclusion: Based upon the "femoral first" principle and "combined anteversion technique" during total hip arthroplasty, these operations has been carried out well enough to meet the patients' needs of performing normal daily activities.

  7. Equally good fixation of cemented and uncemented cups in total trapeziometacarpal joint prostheses. A randomized clinical RSA study with 2-year follow-up.

    PubMed

    Hansen, Torben Baek; Stilling, Maiken

    2013-02-01

    Cup failure is a recognized problem in total trapeziometacarpal (TM) joint prostheses; it may be related to poor fixation, which can be revealed by radiostereometric analysis (RSA). We compared the early implant migration of cemented trapezium cups to that of uncemented screw cups. In a prospective, parallel-group, randomized patient-blinded clinical trial, we included 32 hands in 28 patients (5 males) with a mean age of 58 (40-77) years and with Eaton stage-2 or -3 osteoarthritis of the trapeziometacarpal joint. Patients were randomized to surgery with a cemented DLC all-polyethylene cup (C) (n = 16) or an uncemented hydroxyapatite-coated chrome-cobalt Elektra screw cup (UC) (n = 16). Uncemented cups were inserted without threading of the bone. Stereoradiographs for evaluation of cup migration (primary effect size) and DASH and pain scores were obtained during 2 years of follow-up. The 2-year total translation (TT) was similar (p = 0.2): 0.24 mm (SD 0.10) for the C (n = 11) and 0.19 mm (SD 0.16) for the UC (n = 11). Variances were similar (p = 0.4). Judged by RSA, 2 UC cups and 1 C cup became loose (TT > 1 mm). Both UC cups were found to be loose at revision. Grip strength, pain, and DASH scores were similar between groups at all measurement points. Early implant fixation and clinical outcome were equally good with both cup designs. This is the first clinical RSA study on trapezium cups, and the method appears to be clinically useful for detection of loose implants.

  8. [A method to avoid lengthening lower limbs after total hip arthroplasty in patients with congenital short femoral neck].

    PubMed

    Chen, Tao; Shang, Xifu; He, Rui; Hu, Fei; Ge, Chang

    2012-03-01

    To investigate the method to avoid lengthening lower limbs after total hip arthroplasty in patients with congenital short femoral neck. The clinical data were analyzed retrospectively from 38 patients undergoing unilateral total hip arthroplasty between April 2005 and December 2010. There were 26 males and 12 females, aged 45-78 years (mean, 62.3 years). Among these cases, there were 11 cases of avascular necrosis of the femoral head, 17 cases of hip osteoarthritis, and 10 cases of femoral neck fracture. Before operation, 29 cases had leg length discrepancy; and the shortened length of the legs was 10-24 mm with an average of 14.5 mm by clinical measurement, and was 11-25 mm with an average of 14.7 mm by X-ray film measurement. The Harris score before operation was 44.0 +/- 3.6. At 1 day after operation, 3 cases had legs lengthening by clinical and X-ray film measurement; limb length difference less than 10 mm was regarded as equal limb length in the other 35 patients (92.1%). All incisions healed by first intention, and no complication of infection or lower limb deep venous thrombosis occurred. In 3 patients who had legs lengthening, 1 patient had abnormal gait and slight limping after increasing heel pad because the lower limb was lengthened by 16 mm, and 2 patients had slight limping. The other patients could walk normally and achieved pain relief of hip. Thirty-six patients were followed up 12-68 months (mean, 43.8 months). The Harris score was 86.7 +/- 2.3 after 6 months, showing significant difference (t = 3.260, P = 0.031) when compared with that before operation. The X-ray films showed no prosthetic loosening or subsidence. For patients with congenital short femoral neck during total hip arthroplasty, the surgeons should pay attention to osteotomy plane determination, limb length measurement, and use of the prosthesis with collar to avoid the lengthening lower limbs.

  9. Outcomes after salvage procedures for the painful dislocated hip in cerebral palsy.

    PubMed

    Wright, Patrick B; Ruder, John; Birnbaum, Mark A; Phillips, Jonathan H; Herrera-Soto, Jose A; Knapp, Dennis R

    2013-01-01

    The painful dislocated hip in the setting of cerebral palsy is a challenging problem. Many surgical procedures have been reported to treat this condition with varying success rates. The purpose of this study is to retrospectively evaluate and compare the outcomes of 3 different surgical procedures performed at our institution for pain relief in patients with spastic quadriplegic cerebral palsy and painful dislocated hips. A retrospective chart review of the surgical procedures performed by 5 surgeons for spastic, painful dislocated hips from 1997 to 2010 was performed. The procedures identified were (1) proximal femoral resection arthroplasty (PFRA); (2) subtrochanteric valgus osteotomy (SVO) with femoral head resection; and (3) proximal femur prosthetic interposition arthroplasty (PFIA) using a humeral prosthesis. Outcomes based on pain and range of motion were determined to be excellent, good, fair, or poor by predetermined criteria. Forty-four index surgeries and 14 revision surgeries in 33 patients with an average follow-up of 49 months met the inclusion criteria. Of the index surgeries, 12 hips were treated with a PFRA, 21 with a SVO, and 11 with a PFIA. An excellent or good result was noted in 67% of PFRAs, 67% of SVOs, and 73% of PFIAs. No statistical significance between these procedures was achieved. The 14 revisions were performed because of a poor result from previous surgery, demonstrating a 24% reoperation rate overall. No patients classified as having a fair result underwent revision surgery. All patients receiving revision surgery were eventually classified as having an excellent or good result. Surgical treatment for the painful, dislocated hip in the setting of spastic quadriplegic cerebral palsy remains unsettled. There continue to be a large percentage of failures despite the variety of surgical techniques designed to treat this problem. These failures can be managed, however, and eventually resulted in a good outcome. We demonstrated a trend toward better outcomes with a PFIA, but further study should be conducted to prove statistical significance. III.

  10. A novel method to measure femoral component migration by computed tomography: a cadaver study.

    PubMed

    Boettner, Friedrich; Sculco, Peter; Lipman, Joseph; Renner, Lisa; Faschingbauer, Martin

    2016-06-01

    Radiostereometric analysis (RSA) is the most accurate technique to measure implant migration. However, it requires special equipment, technical expertise and analysis software and has not gained wide acceptance. The current paper analyzes a novel method to measure implant migration utilizing widely available computer tomography (CT). Three uncemented total hip replacements were performed in three human cadavers and six tantalum beads were inserted into the femoral bone similar to RSA. Six different 28 mm heads (-3, 0, 2.5, 5.0, 7.5 and 10 mm) were added to simulate five reproducible translations (maximum total point migration) of the center of the head. Implant migration was measured in a 3-D analysis software (Geomagic Studio 7). Repeat manual reconstructions of the center of the head were performed by two investigators to determine repeatability and accuracy. The accuracy of measurements between the centers of two head sizes was 0.11 mm with a CI 95 % of 0.22 mm. The intra-observer repeatability was 0.13 mm (CI 95 % 0.25 mm). The interrater-reliability was 0.943. CT based measurement of head displacement in a cadaver model were highly accurate and reproducible.

  11. Association between contact hip stress and RSA-measured wear rates in total hip arthroplasties of 31 patients.

    PubMed

    The, Bertram; Hosman, Anton; Kootstra, Johan; Kralj-Iglic, Veronika; Flivik, Gunnar; Verdonschot, Nico; Diercks, Ron

    2008-01-01

    The main concern in the long run of total hip replacements is aseptic loosening of the prosthesis. Optimization of the biomechanics of the hip joint is necessary for optimization of long-term success. A widely implementable tool to predict biomechanical consequences of preoperatively planned reconstructions still has to be developed. A potentially useful model to this purpose has been developed previously. The aim of this study is to quantify the association between the estimated hip joint contact force by this biomechanical model and RSA-measured wear rates in a clinical setting. Thirty-one patients with a total hip replacement were measured with RSA, the gold standard for clinical wear measurements. The reference examination was done within 1 week of the operation and the follow-up examinations were done at 1, 2 and 5 years. Conventional pelvic X-rays were taken on the same day. The contact stress distribution in the hip joint was determined by the computer program HIPSTRESS. The procedure for the determination of the hip joint contact stress distribution is based on the mathematical model of the resultant hip force in the one-legged stance and the mathematical model of the contact stress distribution. The model for the force requires as input data, several geometrical parameters of the hip and the body weight, while the model for stress requires as input data, the magnitude and direction of the resultant hip force. The stress distribution is presented by the peak stress-the maximal value of stress on the weight-bearing area (p(max)) and also by the peak stress calculated with respect to the body weight (p(max)/W(B)) which gives the effect of hip geometry. Visualization of the relations between predicted values by the model and the wear at different points in the follow-up was done using scatterplots. Correlations were expressed as Pearson r values. The predicted p(max) and wear were clearly correlated in the first year post-operatively (r = 0.58, p = 0.002), while this correlation is weaker after 2 years (r = 0.19, p = 0.337) and 5 years (r = 0.24, p = 0.235). The wear values at 1, 2 and 5 years post-operatively correlate with each other in the way that is expected considering the wear velocity curve of the whole group. The correlation between the predicted p(max) values of two observers who were blinded for each other's results was very good (r = 0.93, p < 0.001). We conclude that the biomechanical model used in this paper provides a scientific foundation for the development of a new way of constructing preoperative biomechanical plans for total hip replacements.

  12. A bias-adjusted evidence synthesis of RCT and observational data: the case of total hip replacement.

    PubMed

    Schnell-Inderst, Petra; Iglesias, Cynthia P; Arvandi, Marjan; Ciani, Oriana; Matteucci Gothe, Raffaella; Peters, Jaime; Blom, Ashley W; Taylor, Rod S; Siebert, Uwe

    2017-02-01

    Evaluation of clinical effectiveness of medical devices differs in some aspects from the evaluation of pharmaceuticals. One of the main challenges identified is lack of robust evidence and a will to make use of experimental and observational studies (OSs) in quantitative evidence synthesis accounting for internal and external biases. Using a case study of total hip replacement to compare the risk of revision of cemented and uncemented implant fixation modalities, we pooled treatment effect estimates from OS and RCTs, and simplified existing methods for bias-adjusted evidence synthesis to enhance practical application. We performed an elicitation exercise using methodological and clinical experts to determine the strength of beliefs about the magnitude of internal and external bias affecting estimates of treatment effect. We incorporated the bias-adjusted treatment effects into a generalized evidence synthesis, calculating both frequentist and Bayesian statistical models. We estimated relative risks as summary effect estimates with 95% confidence/credibility intervals to capture uncertainty. When we compared alternative approaches to synthesizing evidence, we found that the pooled effect size strongly depended on the inclusion of observational data as well as on the use bias-adjusted estimates. We demonstrated the feasibility of using observational studies in meta-analyses to complement RCTs and incorporate evidence from a wider spectrum of clinically relevant studies and healthcare settings. To ensure internal validity, OS data require sufficient correction for confounding and selection bias, either through study design and primary analysis, or by applying post-hoc bias adjustments to the results. © 2017 The Authors. Health Economics published by John Wiley & Sons, Ltd. © 2017 The Authors. Health Economics published by John Wiley & Sons, Ltd.

  13. Potential Use of Porous Titanium–Niobium Alloy in Orthopedic Implants: Preparation and Experimental Study of Its Biocompatibility In Vitro

    PubMed Central

    Wang, Xu; Huang, Jia-Zhang; Zhang, Chao; Muhammad, Hassan; Ma, Xin; Liao, Qian-De

    2013-01-01

    Background The improvement of bone ingrowth into prosthesis and enhancement of the combination of the range between the bone and prosthesis are important for long-term stability of artificial joints. They are the focus of research on uncemented artificial joints. Porous materials can be of potential use to solve these problems. Objectives/Purposes This research aims to observe the characteristics of the new porous Ti-25Nb alloy and its biocompatibility in vitro, and to provide basic experimental evidence for the development of new porous prostheses or bone implants for bone tissue regeneration. Methods The Ti-25Nb alloys with different porosities were fabricated using powder metallurgy. The alloys were then evaluated based on several characteristics, such as mechanical properties, purity, pore size, and porosity. To evaluate biocompatibility, the specimens were subjected to methylthiazol tetrazolium (MTT) colorimetric assay, cell adhesion and proliferation assay using acridine staining, scanning electron microscopy, and detection of inflammation factor interleukin-6 (IL-6). Results The porous Ti-25Nb alloy with interconnected pores had a pore size of 200 µm to 500 µm, which was favorable for bone ingrowth. The compressive strength of the alloy was similar to that of cortical bone, while with the elastic modulus closer to cancellous bone. MTT assay showed that the alloy had no adverse reaction to rabbit bone marrow mesenchymal stem cells, with a toxicity level of 0 to 1. Cell adhesion and proliferation experiments showed excellent cell growth on the surface and inside the pores of the alloy. According to the IL-6 levels, the alloy did not cause any obvious inflammatory response. Conclusion All porous Ti-25Nb alloys showed good biocompatibility regardless of the percentage of porosity. The basic requirement of clinical orthopedic implants was satisfied, which made the alloy a good prospect for biomedical application. The alloy with 70% porosity had the optimum mechanical properties, as well as suitable pore size and porosity, which allowed more bone ingrowth. PMID:24260188

  14. Short-term outcome of 1,465 computer-navigated primary total knee replacements 2005–2008

    PubMed Central

    2011-01-01

    Background and purpose Improvement of positioning and alignment by the use of computer-assisted surgery (CAS) might improve longevity and function in total knee replacements, but there is little evidence. In this study, we evaluated the short-term results of computer-navigated knee replacements based on data from the Norwegian Arthroplasty Register. Patients and methods Primary total knee replacements without patella resurfacing, reported to the Norwegian Arthroplasty Register during the years 2005–2008, were evaluated. The 5 most common implants and the 3 most common navigation systems were selected. Cemented, uncemented, and hybrid knees were included. With the risk of revision for any cause as the primary endpoint and intraoperative complications and operating time as secondary outcomes, 1,465 computer-navigated knee replacements (CAS) and 8,214 conventionally operated knee replacements (CON) were compared. Kaplan-Meier survival analysis and Cox regression analysis with adjustment for age, sex, prosthesis brand, fixation method, previous knee surgery, preoperative diagnosis, and ASA category were used. Results Kaplan-Meier estimated survival at 2 years was 98% (95% CI: 97.5–98.3) in the CON group and 96% (95% CI: 95.0–97.8) in the CAS group. The adjusted Cox regression analysis showed a higher risk of revision in the CAS group (RR = 1.7, 95% CI: 1.1–2.5; p = 0.02). The LCS Complete knee had a higher risk of revision with CAS than with CON (RR = 2.1, 95% CI: 1.3–3.4; p = 0.004)). The differences were not statistically significant for the other prosthesis brands. Mean operating time was 15 min longer in the CAS group. Interpretation With the introduction of computer-navigated knee replacement surgery in Norway, the short-term risk of revision has increased for computer-navigated replacement with the LCS Complete. The mechanisms of failure of these implantations should be explored in greater depth, and in this study we have not been able to draw conclusions regarding causation. PMID:21504309

  15. A universal ankle-foot prosthesis emulator for human locomotion experiments.

    PubMed

    Caputo, Joshua M; Collins, Steven H

    2014-03-01

    Robotic prostheses have the potential to significantly improve mobility for people with lower-limb amputation. Humans exhibit complex responses to mechanical interactions with these devices, however, and computational models are not yet able to predict such responses meaningfully. Experiments therefore play a critical role in development, but have been limited by the use of product-like prototypes, each requiring years of development and specialized for a narrow range of functions. Here we describe a robotic ankle-foot prosthesis system that enables rapid exploration of a wide range of dynamical behaviors in experiments with human subjects. This emulator comprises powerful off-board motor and control hardware, a flexible Bowden cable tether, and a lightweight instrumented prosthesis, resulting in a combination of low mass worn by the human (0.96 kg) and high mechatronic performance compared to prior platforms. Benchtop tests demonstrated closed-loop torque bandwidth of 17 Hz, peak torque of 175 Nm, and peak power of 1.0 kW. Tests with an anthropomorphic pendulum "leg" demonstrated low interference from the tether, less than 1 Nm about the hip. This combination of low worn mass, high bandwidth, high torque, and unrestricted movement makes the platform exceptionally versatile. To demonstrate suitability for human experiments, we performed preliminary tests in which a subject with unilateral transtibial amputation walked on a treadmill at 1.25 ms-1 while the prosthesis behaved in various ways. These tests revealed low torque tracking error (RMS error of 2.8 Nm) and the capacity to systematically vary work production or absorption across a broad range (from -5 to 21 J per step). These results support the use of robotic emulators during early stage assessment of proposed device functionalities and for scientific study of fundamental aspects of human-robot interaction. The design of simple, alternate end-effectors would enable studies at other joints or with additional degrees of freedom.

  16. Pseudotumor Caused by Titanium Particles From a Total Hip Prosthesis.

    PubMed

    Sakamoto, Masaaki; Watanabe, Hitoshi; Higashi, Hidetaka; Kubosawa, Hitoshi

    2016-01-01

    A 77-year-old woman underwent metal-on-polyethylene total hip arthroplasty for osteoarthritis of the right hip at another institution. During surgery, the greater trochanter was broken and internal fixation was performed with a trochanteric cable grip reattachment. Although postoperative recovery was uneventful, approximately 6 years later, the patient had severe right hip pain with apparent swelling, and she was referred to the authors' institution. Plain radiographs showed evidence of severe osteolysis in the proximal femur and cable breakage; however, preoperative aspiration culture findings were negative for bacterial growth. Magnetic resonance imaging showed a well-circumscribed mass, presumed to be a pseudotumor. Serum cobalt and chromium levels were within normal limits, and the serum titanium level was high. During surgery, the mass was excised and removal of the cable system revealed a sharp deficit in the bare femoral stem. Gross surgical findings showed no obvious evidence of infection and no corrosion at the head-neck junction; therefore, all components were retained besides the cable system, which resulted in clinical recovery. All of the cultures from specimens were negative for bacterial growth, and histologic findings were compatible with a pseudotumor, such as histiocytes containing metal particles, abundant plasma cells, and CD8-positive cells. Quantitative analysis by inductively coupled plasma atomic emission spectrometry showed that the main source of metal debris in the pseudotumor was the femoral stem, which was made of titanium alloy, not the broken cable, which was made of cobalt-chromium alloy. The findings suggest that titanium particles can form symptomatic solid pseudotumors. Copyright 2016, SLACK Incorporated.

  17. Effects of chronic cobalt and chromium exposure after metal‐on‐metal hip resurfacing: An epigenome‐wide association pilot study

    PubMed Central

    Steinberg, Julia; Shah, Karan M.; Gartland, Alison; Zeggini, Eleftheria

    2017-01-01

    ABSTRACT Metal‐on‐metal (MOM) hip resurfacing has recently been a popular prosthesis choice for the treatment of symptomatic arthritis, but results in the release of cobalt and chromium ions into the circulation that can be associated with adverse clinical effects. The mechanism underlying these effects remains unclear. While chromosomal aneuploidy and translocations are associated with this exposure, the presence of subtle structural epigenetic modifications in patients with MOM joint replacements remains unexplored. Consequently, we analyzed whole blood DNA methylation in 34 OA patients with MOM hip resurfacing (MOM HR) compared to 34 OA patients with non‐MOM total hip replacements (non‐MOM THR), using the genome‐wide Illumina HumanMethylation 450k BeadChip. No probes showed differential methylation significant at 5% false‐discovery rate (FDR). We also tested association of probe methylation levels with blood chromium and cobalt levels directly; there were no significant associations at 5% FDR. Finally, we used the “epigenetic clock” to compare estimated to actual age at sample for all individuals. We found no significant difference between MOM HR and non‐MOM THR, and no correlation of age acceleration with blood metal levels. Our results suggest the absence of large methylation differences systemically following metal exposure, however, larger sample sizes will be required to identify potential small effects. Any DNA methylation changes that may occur in the local periprosthetic tissues remain to be elucidated. © 2017 The Authors. Orthopaedic Research Society. Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 35:2323–2328, 2017. PMID:28098396

  18. Periprosthetic pathology in 'at risk' ceramic-on-polyethylene total hip arthroplasty: a clinical study using MARS-MRI in 50 patients.

    PubMed

    Das, Dirk H; van der Weegen, Walter; Wullems, Jorgen A; Brakel, Koen; Sijbesma, Thea; Nelissen, Rob G

    2016-05-16

    Recent studies of metal-on-metal (MoM) total hip arthroplasty (THA) using metal-artefact-reducing-sequence software for magnetic resonance Imaging (MARS-MRI) have revealed remarkable soft tissue pathology around the hip, usually referred to as pseudotumours. Case reports describe identical pathology in non-MoM THA, but descriptive overviews of MRI abnormalities in patients with non-MoM prosthesis are scarce. A clinical study in a cohort of 50 ceramic-on-polyethylene (CoP) THA selected for high risk of peri-prosthetic pathology including 2 subgroups: (i) 40 patients with a high polyethylene (PE) wear rate (>0.2 mm per year) and 5-12 years follow-up; (ii) 10 patients with a 2 to 5 years follow-up and a documented history of persistent complaints. All patients were clinically evaluated, MARS-MRIs were completed and chrome and cobalt serum samples were taken. 17 scans were normal (34%). Periprosthetic fluid collections were seen as a bursae iliopsoas (n = 12, 24%), in the trochanter bursae (n = 4, 8%) and in the surgical tract (n = 9, 18%). 1 case demonstrated a cyst on MARS-MRI resembling a pseudotumour as seen with MoM THA (2%). Intraosseous acetabular cysts were seen in 12 cases (24%), intraosseous trochanteric cysts in 10 cases (20%). Soft tissue abnormalities after non-MoM THA are common in selected patients and can be clearly visualised with MARS-MRI. Pseudotumours as seen on MARS-MRI do occur in non-MoM hip arthroplasty but with low prevalence.

  19. Reduction of metal artifacts from unilateral hip arthroplasty on dual-energy CT with metal artifact reduction software.

    PubMed

    Yue, Dong; Fan Rong, Cheng; Ning, Cai; Liang, Hu; Ai Lian, Liu; Ru Xin, Wang; Ya Hong, Luo

    2018-07-01

    Background The evaluation of hip arthroplasty is a challenge in computed tomography (CT). The virtual monochromatic spectral (VMS) images with metal artifact reduction software (MARs) in spectral CT can reduce the artifacts and improve the image quality. Purpose To evaluate the effects of VMS images and MARs for metal artifact reduction in patients with unilateral hip arthroplasty. Material and Methods Thirty-five patients underwent dual-energy CT. Four sets of VMS images without MARs and four sets of VMS images with MARs were obtained. Artifact index (AI), CT number, and SD value were assessed at the periprosthetic region and the pelvic organs. The scores of two observers for different images and the inter-observer agreement were evaluated. Results The AIs in 120 and 140 keV images were significantly lower than those in 80 and 100 keV images. The AIs of the periprosthetic region in VMS images with MARs were significantly lower than those in VMS images without MARs, while the AIs of pelvic organs were not significantly different. VMS images with MARs improved the accuracy of CT numbers for the periprosthetic region. The inter-observer agreements were good for all the images. VMS images with MARs at 120 and 140 keV had higher subjective scores and could improve the image quality, leading to reliable diagnosis of prosthesis-related problems. Conclusion VMS images with MARs at 120 and 140 keV could significantly reduce the artifacts from hip arthroplasty and improve the image quality at the periprosthetic region but had no obvious advantage for pelvic organs.

  20. Patient and implant survival following joint replacement because of metastatic bone disease

    PubMed Central

    2013-01-01

    Background Patients suffering from a pathological fracture or painful bony lesion because of metastatic bone disease often benefit from a total joint replacement. However, these are large operations in patients who are often weak. We examined the patient survival and complication rates after total joint replacement as the treatment for bone metastasis or hematological diseases of the extremities. Patients and methods 130 patients (mean age 64 (30–85) years, 76 females) received 140 joint replacements due to skeletal metastases (n = 114) or hematological disease (n = 16) during the period 2003–2008. 21 replaced joints were located in the upper extremities and 119 in the lower extremities. Clinical and survival data were extracted from patient files and various registers. Results The probability of patient survival was 51% (95% CI: 42–59) after 6 months, 39% (CI: 31–48) after 12 months, and 29% (CI: 21–37) after 24 months. The following surgical complications were seen (8 of which led to additional surgery): 2–5 hip dislocations (n = 8), deep infection (n = 3), peroneal palsy (n = 2), a shoulder prosthesis penetrating the skin (n = 1), and disassembly of an elbow prosthesis (n = 1). The probability of avoiding all kinds of surgery related to the implanted prosthesis was 94% (CI: 89–99) after 1 year and 92% (CI: 85–98) after 2 years. Conclusion Joint replacement operations because of metastatic bone disease do not appear to have given a poorer rate of patient survival than other types of surgical treatment, and the reoperation rate was low. PMID:23530874

  1. Nondestructive evaluation of orthopaedic implant stability in THA using highly nonlinear solitary waves

    NASA Astrophysics Data System (ADS)

    Yang, Jinkyu; Silvestro, Claudio; Sangiorgio, Sophia N.; Borkowski, Sean L.; Ebramzadeh, Edward; De Nardo, Luigi; Daraio, Chiara

    2012-01-01

    We propose a new biomedical sensing technique based on highly nonlinear solitary waves to assess orthopaedic implant stability in a nondestructive and efficient manner. We assemble a granular crystal actuator consisting of a one-dimensional tightly packed array of spherical particles, to generate acoustic solitary waves. Via direct contact with the specimen, we inject acoustic solitary waves into a biomedical prosthesis, and we nondestructively evaluate the mechanical integrity of the bone-prosthesis interface, studying the properties of the waves reflected from the contact zone between the granular crystal and the implant. The granular crystal contains a piezoelectric sensor to measure the travelling solitary waves, which allows it to function also as a sensor. We perform a feasibility study using total hip arthroplasty (THA) samples made of metallic stems implanted in artificial composite femurs using polymethylmethacrylate for fixation. We first evaluate the sensitivity of the proposed granular crystal sensor to various levels of prosthesis insertion into the composite femur. Then, we impose a sequence of harsh mechanical loading on the THA samples to degrade the mechanical integrity at the stem-cement interfaces, using a femoral load simulator that simulates aggressive, accelerated physiological loading. We investigate the implant stability via the granular crystal sensor-actuator during testing. Preliminary results suggest that the reflected waves respond sensitively to the degree of implant fixation. In particular, the granular crystal sensor-actuator successfully detects implant loosening at the stem-cement interface following violent cyclic loading. This study suggests that the granular crystal sensor and actuator has the potential to detect metal-cement defects in a nondestructive manner for orthopaedic applications.

  2. IMU-based Real-time Pose Measurement system for Anterior Pelvic Plane in Total Hip Replacement Surgeries.

    PubMed

    Zhe Cao; Shaojie Su; Hao Tang; Yixin Zhou; Zhihua Wang; Hong Chen

    2017-07-01

    With the aging of population, the number of Total Hip Replacement Surgeries (THR) increased year by year. In THR, inaccurate position of the implanted prosthesis may lead to the failure of the operation. In order to reduce the failure rate and acquire the real-time pose of Anterior Pelvic Plane (APP), we propose a measurement system in this paper. The measurement system includes two parts: Initial Pose Measurement Instrument (IPMI) and Real-time Pose Measurement Instrument (RPMI). IPMI is used to acquire the initial pose of the APP, and RPMI is used to estimate the real-time pose of the APP. Both are composed of an Inertial Measurement Unit (IMU) and magnetometer sensors. To estimate the attitude of the measurement system, the Extended Kalman Filter (EKF) is adopted in this paper. The real-time pose of the APP could be acquired together with the algorithm designed in the paper. The experiment results show that the Root Mean Square Error (RMSE) is within 1.6 degrees, which meets the requirement of THR operations.

  3. Prosthetic liner wear in total hip replacement: a longitudinal 13-year study with computed tomography.

    PubMed

    Weidenhielm, Lars; Olivecrona, Henrik; Maguire, Gerald Q; Noz, Marilyn E

    2018-06-01

    This case report follows a woman who had a total hip replacement in 1992 when she was 45 years old. Six serial computed tomography (CT) examinations over a period of 13 years provided information that allowed her revision surgery to be limited to liner replacement as opposed to replacement of the entire prosthesis. Additionally, they provided data that ruled out the presence of osteolysis and indeed none was found at surgery. In 2004, when the first CT was performed, the 3D distance the femoral head had penetrated into the cup was determined to be 2.6 mm. By 2017, femoral head penetration had progressed to 5.0 mm. The extracted liner showed wear at the thinnest part to be 5.5 mm, as measured with a micrometer. The use of modern CT techniques can identify problems, while still correctable without major surgery. Furthermore, the ability of CT to assess the direction of wear revealed that the liner wear changed from the cranial to dorsal direction.

  4. Custom-made endoprostheses for the femoral amputation stump: an alternative to hip disarticulation in tumour surgery.

    PubMed

    Kalson, N S; Gikas, P D; Aston, W; Miles, J; Blunn, G; Pollock, R; Skinner, J; Briggs, T W R; Cannon, S R

    2010-08-01

    Disarticulation of the hip in patients with high-grade tumours in the upper thigh results in significant morbidity. In patients with no disease of the proximal soft tissue a femoral stump may be preserved, leaving a fulcrum for movement and weight-bearing. We reviewed nine patients in whom the oncological decision would normally be to disarticulate, but who were treated by implantation of an endoprosthesis in order to create a functioning femoral stump. The surgery was undertaken for chondrosarcoma in four patients, pleomorphic sarcoma in three, osteosarcoma in one and fibrous dysplasia in one. At follow-up at a mean of 80 months (34 to 132), seven patients were alive and free from disease, one had died from lung metastases and another from a myocardial infarction. The mean functional outcome assessment was 50 (musculoskeletal tumor society), 50 and 60 (physical and mental Short-form 36 scores). Implantation of an endoprosthesis into the stump in carefully selected patients allows fitting of an above-knee prosthesis and improves wellbeing and the functional outcome.

  5. Stabilization of a three-dimensional limit cycle walking model through step-to-step ankle control.

    PubMed

    Kim, Myunghee; Collins, Steven H

    2013-06-01

    Unilateral, below-knee amputation is associated with an increased risk of falls, which may be partially related to a loss of active ankle control. If ankle control can contribute significantly to maintaining balance, even in the presence of active foot placement, this might provide an opportunity to improve balance using robotic ankle-foot prostheses. We investigated ankle- and hip-based walking stabilization methods in a three-dimensional model of human gait that included ankle plantarflexion, ankle inversion-eversion, hip flexion-extension, and hip ad/abduction. We generated discrete feedback control laws (linear quadratic regulators) that altered nominal actuation parameters once per step. We used ankle push-off, lateral ankle stiffness and damping, fore-aft foot placement, lateral foot placement, or all of these as control inputs. We modeled environmental disturbances as random, bounded, unexpected changes in floor height, and defined balance performance as the maximum allowable disturbance value for which the model walked 500 steps without falling. Nominal walking motions were unstable, but were stabilized by all of the step-to-step control laws we tested. Surprisingly, step-by-step modulation of ankle push-off alone led to better balance performance (3.2% leg length) than lateral foot placement (1.2% leg length) for these control laws. These results suggest that appropriate control of robotic ankle-foot prosthesis push-off could make balancing during walking easier for individuals with amputation.

  6. Characterization of the fretting corrosion behavior, surface and debris from head-taper interface of two different modular hip prostheses.

    PubMed

    Dos Santos, Claudio T; Barbosa, Cassio; Monteiro, Maurício J; Abud, Ibrahim C; Caminha, Ieda M V; Roesler, Carlos R M

    2016-09-01

    Modular hip prostheses are flexible to match anatomical variations and to optimize mechanical and tribological properties of each part by using different materials. However, micromotions associated with the modular components can lead to fretting corrosion and, consequently, to release of debris which can cause adverse local tissue reactions in human body. In the present study, the surface damage and residues released during in vitro fretting corrosion tests were characterized by stereomicroscope, SEM and EDS. Two models of modular hip prosthesis were studied: Model SS/Ti Cementless whose stem was made of ASTM F136 Ti-6Al-4V alloy and whose metallic head was made of ASTM F138 austenitic stainless steel, and Model SS/SS Cemented with both components made of ASTM F138 stainless steel. The fretting corrosion tests were evaluated according to the criteria of ASTM F1875 standard. Micromotions during the test caused mechanical wear and material loss in the head-taper interface, resulting in fretting-corrosion. Model SS/SS showed higher grade of corrosion. Different morphologies of debris predominated in each model studied. Small and agglomerated particles were observed in the Model SS/Ti and irregular particles in the Model SS/SS. After 10 million cycles, the Model SS/Ti was more resistant to fretting corrosion than the Model SS/SS. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Appraisal of evidence base for introduction of new implants in hip and knee replacement: a systematic review of five widely used device technologies.

    PubMed

    Nieuwenhuijse, Marc J; Nelissen, R G H H; Schoones, J W; Sedrakyan, A

    2014-09-09

    To determine the evidence of effectiveness and safety for introduction of five recent and ostensibly high value implantable devices in major joint replacement to illustrate the need for change and inform guidance on evidence based introduction of new implants into healthcare. Systematic review of clinical trials, comparative observational studies, and registries for comparative effectiveness and safety of five implantable device innovations. PubMed (Medline), Embase, Web of Science, Cochrane, CINAHL, reference lists of articles, annual reports of major registries, summaries of safety and effectiveness for pre-market application and mandated post-market studies at the US Food and Drug Administration. The five selected innovations comprised three in total hip replacement (ceramic-on-ceramic bearings, modular femoral necks, and uncemented monoblock cups) and two in total knee replacement (high flexion knee replacement and gender specific knee replacement). All clinical studies of primary total hip or knee replacement for symptomatic osteoarthritis in adults that compared at least one of the clinical outcomes of interest (patient centred outcomes or complications, or both) in the new implant group and control implant group were considered. Data searching, abstraction, and analysis were independently performed and confirmed by at least two authors. Quantitative data syntheses were performed when feasible. After assessment of 10,557 search hits, 118 studies (94 unique study cohorts) met the inclusion criteria and reported data related to 15,384 implants in 13,164 patients. Comparative evidence per device innovation varied from four low to moderate quality retrospective studies (modular femoral necks) to 56 studies of varying quality including seven high quality (randomised) studies (high flexion knee replacement). None of the five device innovations was found to improve functional or patient reported outcomes. National registries reported two to 12 year follow-up for revision occurrence related to more than 200,000 of these implants. Reported comparative data with well established alternative devices (over 1,200,000 implants) did not show improved device survival. Moreover, we found higher revision occurrence associated with modular femoral necks (hazard ratio 1.9) and ceramic-on-ceramic bearings (hazard ratio 1.0-1.6) in hip replacement and with high flexion knee implants (hazard ratio 1.0-1.8). We did not find convincing high quality evidence supporting the use of five substantial, well known, and already implemented device innovations in orthopaedics. Moreover, existing devices may be safer to use in total hip or knee replacement. Improved regulation and professional society oversight are necessary to prevent patients from being further exposed to these and future innovations introduced without proper evidence of improved clinical efficacy and safety. © Nieuwenhuijse et al 2014.

  8. Appraisal of evidence base for introduction of new implants in hip and knee replacement: a systematic review of five widely used device technologies

    PubMed Central

    Nieuwenhuijse, Marc J; Nelissen, R G H H; Schoones, J W

    2014-01-01

    Objective To determine the evidence of effectiveness and safety for introduction of five recent and ostensibly high value implantable devices in major joint replacement to illustrate the need for change and inform guidance on evidence based introduction of new implants into healthcare. Design Systematic review of clinical trials, comparative observational studies, and registries for comparative effectiveness and safety of five implantable device innovations. Data sources PubMed (Medline), Embase, Web of Science, Cochrane, CINAHL, reference lists of articles, annual reports of major registries, summaries of safety and effectiveness for pre-market application and mandated post-market studies at the US Food and Drug Administration. Study selection The five selected innovations comprised three in total hip replacement (ceramic-on-ceramic bearings, modular femoral necks, and uncemented monoblock cups) and two in total knee replacement (high flexion knee replacement and gender specific knee replacement). All clinical studies of primary total hip or knee replacement for symptomatic osteoarthritis in adults that compared at least one of the clinical outcomes of interest (patient centred outcomes or complications, or both) in the new implant group and control implant group were considered. Data searching, abstraction, and analysis were independently performed and confirmed by at least two authors. Quantitative data syntheses were performed when feasible. Results After assessment of 10 557 search hits, 118 studies (94 unique study cohorts) met the inclusion criteria and reported data related to 15 384 implants in 13 164 patients. Comparative evidence per device innovation varied from four low to moderate quality retrospective studies (modular femoral necks) to 56 studies of varying quality including seven high quality (randomised) studies (high flexion knee replacement). None of the five device innovations was found to improve functional or patient reported outcomes. National registries reported two to 12 year follow-up for revision occurrence related to more than 200 000 of these implants. Reported comparative data with well established alternative devices (over 1 200 000 implants) did not show improved device survival. Moreover, we found higher revision occurrence associated with modular femoral necks (hazard ratio 1.9) and ceramic-on-ceramic bearings (hazard ratio 1.0-1.6) in hip replacement and with high flexion knee implants (hazard ratio 1.0-1.8). Conclusion We did not find convincing high quality evidence supporting the use of five substantial, well known, and already implemented device innovations in orthopaedics. Moreover, existing devices may be safer to use in total hip or knee replacement. Improved regulation and professional society oversight are necessary to prevent patients from being further exposed to these and future innovations introduced without proper evidence of improved clinical efficacy and safety. PMID:25208953

  9. Comparison of cemented and uncemented fixation in total knee arthroplasty.

    PubMed

    Brown, Thomas E; Harper, Benjamin L; Bjorgul, Kristian

    2013-05-01

    As a result of reading this article, physicians should be able to :1. Understand the rationale behind using uncemented fixation in total knee arthroplasty.2.Discuss the current literature comparing cemented and uncemented total knee arthroplasty3. Describe the value of radiostereographic analysis in assessing implant stability.4. Appreciate the limitations in the available literature advocating 1 mode of fixation in total knee arthroplasty. Total knee arthroplasty performed worldwide uses either cemented, cementless, or hybrid (cementless femur with a cemented tibia) fixation of the components. No recent literature review concerning the outcomes of cemented vs noncemented components has been performed. Noncemented components offer the potential advantage of a biologic interface between the bone and implants, which could demonstrate the greatest advantage in long-term durable fixation in the follow-up of young patients undergoing arthroplasty. Several advances have been made in the backing of the tibial components that have not been available long enough to yield long-term comparative follow-up studies. Short-term radiostereographic analysis studies have yielded differing results. Although long-term, high-quality studies are still needed, material advances in biologic fixation surfaces, such as trabecular metal and hydroxyapatite, may offer promising results for young and active patients undergoing total knee arthroplasty when compared with traditional cemented options. Copyright 2013, SLACK Incorporated.

  10. The influence of stem length and fixation on initial femoral component stability in revision total knee replacement

    PubMed Central

    Conlisk, N.; Gray, H.; Pankaj, P.; Howie, C. R.

    2012-01-01

    Objectives Orthopaedic surgeons use stems in revision knee surgery to obtain stability when metaphyseal bone is missing. No consensus exists regarding stem size or method of fixation. This in vitro study investigated the influence of stem length and method of fixation on the pattern and level of relative motion at the bone–implant interface at a range of functional flexion angles. Methods A custom test rig using differential variable reluctance transducers (DVRTs) was developed to record all translational and rotational motions at the bone–implant interface. Composite femurs were used. These were secured to permit variation in flexion angle from 0° to 90°. Cyclic loads were applied through a tibial component based on three peaks corresponding to 0°, 10° and 20° flexion from a normal walking cycle. Three different femoral components were investigated in this study for cementless and cemented interface conditions. Results Relative motions were found to increase with flexion angle. Stemmed implants reduced relative motions in comparison to stemless implants for uncemented constructs. Relative motions for cemented implants were reduced to one-third of their equivalent uncemented constructs. Conclusions Stems are not necessary for cemented implants when the metaphyseal bone is intact. Short cemented femoral stems confer as much stability as long uncemented stems. PMID:23610659

  11. Influence of press-fit parameters on the primary stability of uncemented femoral resurfacing implants.

    PubMed

    Gebert, A; Peters, J; Bishop, N E; Westphal, F; Morlock, M M

    2009-01-01

    Primary stability is essential to the success of uncemented prostheses. It is strongly influenced by implantation technique, implant design and bone quality. The goal of this study was to investigate the effect of press-fit parameters on the primary stability of uncemented femoral head resurfacing prostheses. An in vitro study with human specimens and prototype implants (nominal radial interference 170 and 420 microm) was used to investigate the effect of interference on primary stability. A finite element model was used to assess the influence of interference, friction between implant and bone, and bone quality. Primary stability was represented by the torque capacity of the implant. The model predicted increasing stability with actual interference, bone quality and friction coefficient; plastic deformation of the bone began at interferences of less than 100 microm. Experimentally, however, stability was not related to interference. This may be due to abrasion or the collapse of trabecular bone structures at higher interferences, which could not be captured by the model. High nominal interferences as tested experimentally appear unlikely to result in improved stability clinically. An implantation force of about 2,500 N was estimated to be sufficient to achieve a torque capacity of about 30 N m with a small interference (70 microm).

  12. Low Preoperative BMD Is Related to High Migration of Tibia Components in Uncemented TKA-92 Patients in a Combined DEXA and RSA Study With 2-Year Follow-Up.

    PubMed

    Andersen, Mikkel R; Winther, Nikkolaj S; Lind, Thomas; Schrøder, Henrik M; Flivik, Gunnar; Petersen, Michael M

    2017-07-01

    The fixation of uncemented tibia components in total knee arthroplasty may rely on the bone quality of the tibia; however, no previous studies have shown convincing objective proof of this. Component migration is relevant as it has been shown to predict aseptic loosening. We performed 2-year follow-up of 92 patients who underwent total knee arthroplasty surgery with an uncemented tibia component. Bone mineral density (BMD; g/cm 2 ) of the tibia host bone was measured preoperatively using dual energy X-ray absorptiometry. The proximal tibia was divided into 2 regions of interest (ROI) in the part of the tibia bone where the components were implanted. Radiostereometric analysis was performed postoperatively and after 3, 6, 12, and 24 months. The primary outcome was maximum total point motion (MTPM; mm). Regression analysis was performed to evaluate the relation between preoperative BMD and MTPM. We found low preoperative BMD in ROI1 to be significantly related to high MTPM at all follow-ups: after 3 months (R 2  = 20%, P BMD  = 0.017), 6 months (R 2  = 29%, P BMD  = 0.003), 12 months (R 2  = 33%, P BMD  = 0.001), and 24 months (R 2  = 27%, P BMD  = 0.001). We also found a significant relation for low BMD in ROI2 and high MTPM: 3 months (R 2  = 19%, P BMD  = 0.042), 6 months (R 2  = 28%, P BMD  = 0.04), 12 months (R 2  = 32%, P BMD  = 0.004), and 24 months (R 2  = 24%, P BMD  = 0.005). Low preoperative BMD in the tibia is related to high MTPM. Thus, high migration of uncemented tibia components is to be expected in patients with poor bone quality. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. [Trochanteric femoral fractures: anatomy, biomechanics and choice of implants].

    PubMed

    Bonnaire, F; Lein, T; Bula, P

    2011-06-01

    The objective of any surgical care of a trochanteric femoral fracture should be the achievement of a stable osteosynthesis that allows early full weight-bearing mobilisation of the patient, because long-term immobilisation soon becomes a vital threat to the affected patients who are usually elderly with correlating comorbidities. The anatomical references of the proximal femur and the structure of the hip joint contain some specifics that play an essential role in the incurrence of a trochanteric femoral fracture and the planning of the osteosynthesis as well. With reposition and fracture stabilisation particular importance must be attached to the collo-diaphyseal and the antetorsion angle so that they do not interfere with the functional interaction of the hip and knee joint. Uncomplex trochanteric fractures ordinarily stabilise sufficiently after reposition so that even an extramedullary implant can ensure full weight-bearing stability. With evermore distal fracture course and intertrochanteric comminution zone, rotational instability and pivot transfer of the fracture area to lateral and caudal are followed by an increase of the dislocating forces. These kinds of fractures (A2 and A3 according to the AO/ASIF classification) profit from an intramedullary and rotationally stable osteosynthesis. Basically primary total hip arthroplasty is a potential option for surgical care of a trochanteric fracture in elderly patients with relevant coxarthrosis. However this procedure can only be recommended in cases of a stable uncomplex fracture. The more the medial interlocking of the proximal femur is destroyed the more difficult it will be to primarily implant a total hip prosthesis with good offset and without a varus and rotational failure in the fracture zone.The current studies in the main show disadvantages due to increased complications in these patients, so that in cases of an unstable trochanteric fracture a primary osteosynthesis should be performed followed by total hip arthroplasty after fracture consolidation has occurred.

  14. Reduction of metal artifacts from hip prostheses on CT images of the pelvis: value of iterative reconstructions.

    PubMed

    Morsbach, Fabian; Bickelhaupt, Sebastian; Wanner, Guido A; Krauss, Andreas; Schmidt, Bernhard; Alkadhi, Hatem

    2013-07-01

    To assess the value of iterative frequency split-normalized (IFS) metal artifact reduction (MAR) for computed tomography (CT) of hip prostheses. This study had institutional review board and local ethics committee approval. First, a hip phantom with steel and titanium prostheses that had inlays of water, fat, and contrast media in the pelvis was used to optimize the IFS algorithm. Second, 41 consecutive patients with hip prostheses who were undergoing CT were included. Data sets were reconstructed with filtered back projection, the IFS algorithm, and a linear interpolation MAR algorithm. Two blinded, independent readers evaluated axial, coronal, and sagittal CT reformations for overall image quality, image quality of pelvic organs, and assessment of pelvic abnormalities. CT attenuation and image noise were measured. Statistical analysis included the Friedman test, Wilcoxon signed-rank test, and Levene test. Ex vivo experiments demonstrated an optimized IFS algorithm by using a threshold of 2200 HU with four iterations for both steel and titanium prostheses. Measurements of CT attenuation of the inlays were significantly (P < .001) more accurate for IFS when compared with filtered back projection. In patients, best overall and pelvic organ image quality was found in all reformations with IFS (P < .001). Pelvic abnormalities in 11 of 41 patients (27%) were diagnosed with significantly (P = .002) higher confidence on the basis of IFS images. CT attenuation of bladder (P < .001) and muscle (P = .043) was significantly less variable with IFS compared with filtered back projection and linear interpolation MAR. In comparison with that of FBP and linear interpolation MAR, noise with IFS was similar close to and far from the prosthesis (P = .295). The IFS algorithm for CT image reconstruction significantly reduces metal artifacts from hip prostheses, improves the reliability of CT number measurements, and improves the confidence for depicting pelvic abnormalities.

  15. The effect of cup outer sizes on the contact mechanics and cement fixation of cemented total hip replacements.

    PubMed

    Hua, Xijin; Li, Junyan; Wang, Ling; Wilcox, Ruth; Fisher, John; Jin, Zhongmin

    2015-10-01

    One important loosening mechanism of the cemented total hip arthroplasty is the mechanical overload at the bone-cement interface and consequent failure of the cement fixation. Clinical studies have revealed that the outer diameter of the acetabular component is a key factor in influencing aseptic loosening of the hip arthroplasty. The aim of the present study was to investigate the influence of the cup outer diameter on the contact mechanics and cement fixation of a cemented total hip replacement (THR) with different wear penetration depths and under different cup inclination angles using finite element (FE) method. A three-dimensional FE model was developed based on a typical Charnley hip prosthesis. Two acetabular cup designs with outer diameters of 40 and 43 mm were modelled and the effect of cup outer diameter, penetration depth and cup inclination angle on the contact mechanics and cement fixation stresses in the cemented THR were studied. The results showed that for all penetration depths and cup inclination angles considered, the contact mechanics in terms of peak von Mises stress in the acetabular cup and peak contact pressure at the bearing surface for the two cup designs were similar (within 5%). However, the peak von Mises stress, the peak maximum principal stress and peak shear stress in the cement mantle at the bone-cement interface for the 43 mm diameter cup design were predicted to be lower compared to those for the 40 mm diameter cup design. The differences were predicted to be 15-19%, 15-22% and 18-20% respectively for different cup penetration depths and inclination angles, which compares to the clinical difference of aseptic loosening incidence of about 20% between the two cup designs. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

  16. Nationwide multicenter follow-up cohort study of hip arthroplasties performed for osteonecrosis of the femoral head.

    PubMed

    Kobayashi, Seneki; Kubo, Toshikazu; Iwamoto, Yukihide; Fukushima, Wakaba; Sugano, Nobuhiko

    2018-05-12

    To identify modifiable factors related to post-operative dislocation and reoperation in patients with osteonecrosis of the femoral head (ONFH) in a large cohort. We studied 4995 hip arthroplasties: total hip arthroplasty (THA) was performed in 79% of patients; bipolar hemiarthroplasty (BP), 17%; total resurfacing arthroplasty (tRS), 3%; and hemi-resurfacing arthroplasty (hRS), 1%. A new type of BP (accounting for 49% of BPs) comprised a femoral component with a polished or smooth, small-diameter (approximately 10 mm) neck with a round or oval axial cut surface and no sharp corners. The infection rate was relatively low (0.56%) even though 58% of cases of ONFH were associated with systemic steroid use, a known risk factor for infection. Post-operative dislocation occurred in 4.3% of cases, with re-operation needed in 3.9%. The dislocation rate was related to surgery type: 5.2% in THA, 0.9% in BP, and 0% in tRS and hRS. Among total arthroplasties with six month or longer follow-up (3670 THAs and 159 tRSs), the risk factors for post-operative dislocation were younger (≤ 40 years) or older (≥ 62 years) age, higher body weight, posterolateral approach, and smaller prosthetic head diameter. Regarding the need for re-operation, higher body weight and surgery type were identified as risk factors. The relatively high dislocation rate of 5.2% in THA is a cause for concern. The identified risk factors for dislocation should be considered when selecting THA for treatment. Prosthesis survivorship in hRSs was inferior to that in BPs or THAs. Body weight also affected the survivorship of hip arthroplasties.

  17. Postoperative changes in in vivo measured friction in total hip joint prosthesis during walking.

    PubMed

    Damm, Philipp; Bender, Alwina; Bergmann, Georg

    2015-01-01

    Loosening of the artificial cup and inlay is the most common reasons for total hip replacement failures. Polyethylene wear and aseptic loosening are frequent reasons. Furthermore, over the past few decades, the population of patients receiving total hip replacements has become younger and more active. Hence, a higher level of activity may include an increased risk of implant loosening as a result of friction-induced wear. In this study, an instrumented hip implant was used to measure the contact forces and friction moments in vivo during walking. Subsequently, the three-dimensional coefficient of friction in vivo was calculated over the whole gait cycle. Measurements were collected from ten subjects at several time points between three and twelve months postoperative. No significant change in the average resultant contact force was observed between three and twelve months postoperative. In contrast, a significant decrease of up to 47% was observed in the friction moment. The coefficient of friction also decreased over postoperative time on average. These changes may be caused by 'running-in' effects of the gliding components or by the improved lubricating properties of the synovia. Because the walking velocity and contact forces were found to be nearly constant during the observed period, the decrease in friction moment suggests an increase in fluid viscosity. The peak values of the contact force individually varied by 32%-44%. The friction moment individually differed much more, by 110%-129% at three and up to 451% at twelve months postoperative. The maximum coefficient of friction showed the highest individual variability, about 100% at three and up to 914% at twelve months after surgery. These individual variations in the friction parameters were most likely due to different 'running-in' effects that were influenced by the individual activity levels and synovia properties.

  18. Midterm Outcomes of Revision Total Hip Arthroplasty With the Use of a Multihole Highly-Porous Titanium Shell.

    PubMed

    Delanois, Ronald E; Gwam, Chukwuweike U; Mohamed, Nequesha; Khlopas, Anton; Chughtai, Morad; Malkani, Arthur L; Mont, Michael A

    2017-09-01

    We are reporting on the minimum 5-year outcomes of patients who underwent revision total hip arthroplasty (THA) using a specific highly-porous titanium shell. We assessed (1) aseptic and all-cause survivorship; (2) functional outcomes; (3) complications; and (4) radiographic outcomes. Two hospital databases were evaluated for patients who underwent revision THA due to component instability or aseptic loosening using a cementless highly-porous titanium shell between September 2006 and December 2011. This yielded 35 patients who had a mean age of 61 years (range 14-88 years). Patients had a mean follow-up of 6 years (minimum 5 years). All-cause and aseptic survivorship of the shell was calculated. Functional outcomes were assessed using the Harris Hip Score. We determined the incidence of postoperative complications and performed radiographic evaluation of pelvic radiographs from regular office visits. The aseptic survivorship of the acetabular component was 97% (95% confidence interval; 8.1-9.5). The all-cause survivorship of the acetabular component was 91% (95% confidence interval; 7.3-8.1). One patient had an aseptic failure and 2 patients had septic failures. The mean postoperative Harris Hip Score was 76 points (range, 61-91 points). Excluding the aseptic and septic failures, there was no osteolysis or progressive radiolucencies present on radiographic evaluation at final follow-up. At a minimum of 5-year follow-up, the highly-porous titanium acetabular revision shell has excellent survivorship and functional outcomes. Although long-term follow-up is needed to further monitor these implants, the results are promising and demonstrate that this prosthesis may be an excellent option for patients undergoing revision THA. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Correlation of quantitative histopathological morphology and quantitative radiological analysis during aseptic loosening of hip endoprostheses.

    PubMed

    Bertz, S; Kriegsmann, J; Eckardt, A; Delank, K-S; Drees, P; Hansen, T; Otto, M

    2006-01-01

    Aseptic hip prosthesis loosening is the most important long-term complication in total hip arthroplasty. Polyethylene (PE) wear is the dominant etiologic factor in aseptic loosening, which together with other factors induces mechanisms resulting in bone loss, and finally in implant loosening. The single-shot radiograph analysis (EBRA, abbreviation for the German term "Einzel-Bild-Röntgenanalyse") is a computerized method for early radiological prediction of aseptic loosening. In this study, EBRA parameters were correlated with histomorphological parameters of the periprosthetic membrane. Periprosthetic membranes obtained from 19 patients during revision surgery of loosened ABG I-type total hip pros-theses were analyzed histologically and morphometrically. The pre-existing EBRA parameters, the thickness of the PE debris lay-er and the dimension of inclination and anteversion, were compared with the density of macrophages and giant cells. Addi-tionally, the semiquantitatively determined density of lymphocytes, plasma cells, giant cells and the size of the necrotic areas were correlated with the EBRA results. All periprosthetic membranes were classified as debris-induced type membranes. We found a positive correlation between the number of giant cells and the thickness of the PE debris layer. There was no significant correlation between the number of macrophages or all semiquantitative parameters and EBRA parameters. The number of giant cells decreased with implant duration. The morphometrically measured number of foreign body giant cells more closely reflects the results of the EBRA. The semiquantitative estimation of giant cell density could not substitute for the morphometrical analysis. The density of macrophages, lymphocytes, plasma cells and the size of necrotic areas did not correlate with the EBRA parameters, indicating that there is no correlation with aseptic loosening.

  20. Dose calculations using artificial neural networks: A feasibility study for photon beams

    NASA Astrophysics Data System (ADS)

    Vasseur, Aurélien; Makovicka, Libor; Martin, Éric; Sauget, Marc; Contassot-Vivier, Sylvain; Bahi, Jacques

    2008-04-01

    Direct dose calculations are a crucial requirement for Treatment Planning Systems. Some methods, such as Monte Carlo, explicitly model particle transport, others depend upon tabulated data or analytic formulae. However, their computation time is too lengthy for clinical use, or accuracy is insufficient, especially for recent techniques such as Intensity-Modulated Radiotherapy. Based on artificial neural networks (ANNs), a new solution is proposed and this work extends the properties of such an algorithm and is called NeuRad. Prior to any calculations, a first phase known as the learning process is necessary. Monte Carlo dose distributions in homogeneous media are used, and the ANN is then acquired. According to the training base, it can be used as a dose engine for either heterogeneous media or for an unknown material. In this report, two networks were created in order to compute dose distribution within a homogeneous phantom made of an unknown material and within an inhomogeneous phantom made of water and TA6V4 (titanium alloy corresponding to hip prosthesis). All NeuRad results were compared to Monte Carlo distributions. The latter required about 7 h on a dedicated cluster (10 nodes). NeuRad learning requires between 8 and 18 h (depending upon the size of the training base) on a single low-end computer. However, the results of dose computation with the ANN are available in less than 2 s, again using a low-end computer, for a 150×1×150 voxels phantom. In the case of homogeneous medium, the mean deviation in the high dose region was less than 1.7%. With a TA6V4 hip prosthesis bathed in water, the mean deviation in the high dose region was less than 4.1%. Further improvements in NeuRad will have to include full 3D calculations, inhomogeneity management and input definitions.

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