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Sample records for hip dislocation

  1. Do normal hips dislocate?

    PubMed

    Alshameeri, Zeiad; Rehm, Andreas

    2014-11-01

    There have been a small number of case reports describing late normal-hip dislocations in children who were later diagnosed with developmental dysplasia of the hip. Here, we contest the assumption that normal hips can dislocate. We argue that (as in our case) the ultrasound scans in all published case reports on late dislocated normal hips did not show results that were entirely normal and therefore, so far, there has been no convincing evidence of a dislocation of a normal hip. We also want to highlight the importance of meticulous ultrasound and clinical assessments of high-risk children by an experienced orthopaedic surgeon. PMID:25144883

  2. Congenital hip dislocation (image)

    MedlinePlus

    ... by a blow, fall, or other trauma, a dislocation can also occur from birth. The cause is unknown but genetic factors may play a role. Problems resulting from very mild developmental dysplasia of the hip may not become apparent until the person is ...

  3. [Traumatic hip dislocation in childhood].

    PubMed

    Stachel, P; Hofmann-v Kap-herr, S; Schild, H

    1989-06-01

    The article reports on eight cases of traumatic dislocation of the hip in children. Six of these were genuine dislocations and two dislocation fractures. The children were between 5 and 13 years of age at the time of injury. Seven of these 8 children could be followed up one to 21 years after the accident. All 7 children were free from complaints at the time of follow-up examination; in one case only we found a moderate loss of function in the injured hip joint. In this patient the x-ray film showed deformation of the head of the femur after partial necrosis of the femoral head, as well as initial signs of coxarthrosis. Prognosis of this rare injury in children is favourable if repositioning is performed in time and if relief of the hip is effected for the proper period of time, depending on the individual case. PMID:2665382

  4. Arthroscopic Treatment of Traumatic Hip Dislocation.

    PubMed

    Begly, John P; Robins, Bryan; Youm, Thomas

    2016-05-01

    Traumatic hip dislocations are high-energy injuries that often result in considerable morbidity. Although appropriate management improves outcomes, associated hip pathology may complicate the recovery and lead to future disability and pain. Historically, open reduction has been the standard of care for treating hip dislocations that require surgical intervention. The use of hip arthroscopy to treat the sequelae and symptoms resulting from traumatic hip dislocations recently has increased, however. When used appropriately, hip arthroscopy is a safe, effective, and minimally invasive treatment option for intra-articular pathology secondary to traumatic hip dislocation. PMID:27007728

  5. Developmental Dislocation (Dysplasia) of the Hip (DDH)

    MedlinePlus

    ... developmental dysplasia (dislocation) of the hip (DDH), the hip joint has not formed normally. The ball is loose ... be taken to provide detailed pictures of the hip joint. Treatment When DDH is detected at birth, it ...

  6. Atraumatic Anterior Dislocation of the Hip Joint

    PubMed Central

    Ohtsuru, Tadahiko; Morita, Yasuyuki; Murata, Yasuaki; Itou, Junya; Morita, Yuji; Munakata, Yutaro; Kato, Yoshiharu

    2015-01-01

    Dislocation of the hip joint in adults is usually caused by high-energy trauma such as road traffic accidents or falls from heights. Posterior dislocation is observed in most cases. However, atraumatic anterior dislocation of the hip joint is extremely rare. We present a case of atraumatic anterior dislocation of the hip joint that was induced by an activity of daily living. The possible causes of this dislocation were anterior capsule insufficiency due to developmental dysplasia of the hip, posterior pelvic tilt following thoracolumbar kyphosis due to vertebral fracture, and acetabular anterior coverage changes by postural factor. Acetabular anterior coverage changes in the sagittal plane were measured using a tomosynthesis imaging system. This system was useful for elucidation of the dislocation mechanism in the present case. PMID:26819791

  7. A Bilateral Traumatic Hip Obturator Dislocation

    PubMed Central

    Karaarslan, Ahmet Adnan; Acar, Nihat; Karci, Tolga; Sesli, Erhan

    2016-01-01

    A case of a bilateral simultaneous traumatic obturator dislocation of both hip joints in an 18-year-old young man following a traffic accident is presented. We reduced the dislocated femoral heads immediately under general anesthesia followed by passive and active exercises and early full-weight bearing mobilization. After 5 years, the result was excellent. PMID:26977327

  8. Dislocation of the hip (image)

    MedlinePlus

    A dislocation is an injury in which a bone is displaced from its proper position. Unless there are accompanying fractures or tissue damage, a simple dislocation may be manipulated back into place. Recovery may ...

  9. Traumatic posterior dislocation of hip in children.

    PubMed

    Kutty, S; Thornes, B; Curtin, W A; Gilmore, M F

    2001-02-01

    Traumatic posterior dislocation of the hip joint in children is an uncommon injury. It constitutes a true orthopedic emergency. It makes up over 80% of pediatric hip dislocations. In children, it can occur as a result of minimal trauma, which is attributed to a soft pliable acetabulum and ligamentous laxity. In skeletally mature adolescents, a greater force is required to dislocate the hip joint. Delay in reduction is associated with long-term complications such as avascular necrosis and degenerative arthritis. Avascular necrosis is related to the duration of dislocation. A poorer prognosis is associated with delay in reduction beyond 6 hours, advanced skeletal maturity, or multiple traumas. Prompt reduction minimizes complications. We report two cases of traumatic posterior dislocation of hip in children aged 3 and 14 years. Both were reduced within 6 hours of dislocation, and review at 6 months revealed normal examination and no evidence of any post-traumatic changes. Post-reduction treatment remains without a consensus. This review highlights the clinical presentation, management, and time-sensitive complications of the injury. PMID:11265904

  10. Bilateral traumatic hip dislocation with sciatic nerve palsy.

    PubMed

    Fan, Ka Yuk; Lui, Tun Hing

    2015-01-01

    Bilateral hip dislocation is a rare condition. We report a case of traumatic bilateral hip dislocation and unilateral sciatic nerve palsy in a young woman with known idiopathic scoliosis. With prompt reduction of the dislocated hips, there was reasonable neurological recovery. There was no avascular necrosis of the femoral head or post-traumatic arthritis up to 3-year follow-up. The gender difference in incidence, as well as the predisposition of hip dislocation in scoliosis is discussed. In our case, the decreased femoral anteversion was the culprit. PMID:25809426

  11. [Hip dislocation. Organization of screening and follow-up].

    PubMed

    Abuamara, S; Dacher, J N; Gaucher, S; Lechevallier, J; Brossard, V; Delhaye, L; Durand, C; Levasseur, F; Henocq, A

    1999-06-01

    Early detection and low-risk treatment are the two main objectives of the management of developmental dislocation of the hip. The best way to evaluate neonatal hips is to perform clinical and ultrasound examinations at the same time, and to confront their results. Early diagnosis allows to restrict treatment to infants with neonatal dislocation who do not improve by 4 weeks of age. On the other hand, neonates with reductible dislocated hips must be treated at birth and followed at the joint consultation. Early diagnosis and management must not decrease later efforts to detect dislocated hip until walking age. PMID:10394462

  12. Painful Spastic Hip Dislocation: Proximal Femoral Resection

    PubMed Central

    Albiñana, Javier; Gonzalez-Moran, Gaspar

    2002-01-01

    The dislocated hip in a non-ambulatory child with spastic paresis tends to be a painful interference to sleep, sitting upright, and perineal care. Proximal femoral resection-interposition arthroplasty is one method of treatment for this condition. We reviewed eight hips, two bilateral cases, with a mean follow-up of 30 months. Clinical improvement was observed in all except one case, with respect to pain relief and sitting tolerance. Some proximal migration was observed in three cases, despite routine post-operative skeletal traction in all cases and careful soft tissue interposition. One case showed significant heterotopic ossification which restricted prolonged sitting. This patient needed some occasional medication for pain. PMID:12180614

  13. [Juvenile hip dislocation and the Vojta neuro-physiotherapy].

    PubMed

    Schütt, B

    1981-09-17

    Partial dislocation of the hip in case of cerebral palsy is a result of the disturbance of the neuromuscular system. Immobilization cannot improve the inadequate function the hip. A case of a girl is reported; stabilization of the hip after 3 years of neurophysio-therapy after Vojta could be achieved. PMID:7274945

  14. Neglected Posterior Dislocation of Hip in Children - A Case Report

    PubMed Central

    Pal, Chandra Prakash; Kumar, Deepak; Sadana, Ashwani; Dinkar, Karuna Shankar

    2014-01-01

    Introduction: Traumatic dislocation of the hip in children is a rare injury. We report the outcome of 2 patients of neglected hip dislocation which were treated by open reduction and internal fixation by k-wires. Case Report: We treat 2 children both girls (one was of 4 years and other was 7 years of age). In both cases dislocation was unilateral and was not associated with any facture. Both cases were of posterior dislocation. in both cases open reduction and internal fixation was done by k wires. Hip spica was applied post operatively in both cases. The k wire was removed at 3 to 4 weeks. Patients were allowed to bear weight from gradual to full weight bearing after 6 weeks. Conclusion: We conclude that open reduction is a satisfactory treatment for neglected hip dislocation. It prevents not only deformity but also maintains limb length. PMID:27298953

  15. Traumatic inferior hip dislocation: a rare adult case with ipsilateral bifocal hip fracture

    PubMed Central

    El Hajj Moussa, Majd; Tawk, Charbel; Hoyek, Fadi; Lahoud, Jean-Claude

    2016-01-01

    Inferior dislocation is a rare type of hip dislocation, especially in adults. Few cases have been reported; most of them were isolated. This is the case of a traumatic adult hip dislocation after a road traffic accident. Reduction was made under general anaesthesia; a CT-Scan after the reduction showed a bifocal non-displaced hip fracture. In this article, we present a small review of the literature and we discuss the possible mechanism of hip dislocation. We found through our case study that this condition is not exclusive to children and CT-Scan is mandatory after the reduction of hip dislocation to eliminate any associated injury. To our knowledge, a bifocal hip fracture has not previously been documented, in the English language literature. PMID:27141043

  16. Traumatic Hip Dislocation with Associated Femoral Head Fracture

    PubMed Central

    Dortaj, H.; Emamifar, A.

    2015-01-01

    Dislocation of the hip is a critical injury that results from high-energy trauma. This paper describes a case of posterior dislocation of the right hip in a 35-year-old woman with associated ipsilateral femoral head fracture. Initial treatment included reduction of the right hip through posterior approach and fixation of the femoral head fracture with three absorbable screws. After 15-month follow-up, a full range of motion has been achieved and there are no signs of avascular necrosis, hip instability, or limping. The authors describe their method of surgery. PMID:25874147

  17. Posterior dislocation of the hip while playing basketball.

    PubMed

    Tennent, T D; Chambler, A F; Rossouw, D J

    1998-12-01

    Injuries in basketball are usually to the ankles and knees. Dislocation of the hip is usually associated with severe trauma--for example, road traffic accidents. A case is reported here in which a 22 year old club basketball player slipped on landing from a jump shot, forcing him into a side splits position from which he sustained a posterior dislocation of the hip resulting in a sciatic nerve palsy. PMID:9865411

  18. Open Anterior Dislocation of the Hip in Togo

    PubMed Central

    Anani, Abalo; Yannick, Dellanh; Gamal, Ayouba; Assang, Dossim

    2016-01-01

    Anterior traumatic dislocations of the hip are much less common than posterior dislocations. To date, 14 cases of open anterior dislocation of the hip associated with such injuries, acetabular and femoral head fractures and femoral vascular and nerve damage have been reported. We present a case of a 23-year-old male who sustained open anterior dislocation of the hip with ipsilateral fracture of the greater trochanter after an accident on the public highway. Additional lesions included an iliac wing fracture and a perineal wound. We report this case because of the rarity and seriousness of this injury due to its progressive complications and difficulties related to its management, which are typical to a developing country like ours. PMID:27247749

  19. Surgical hip dislocation for treatment of cam femoroacetabular impingement

    PubMed Central

    Chaudhary, Milind M; Chaudhary, Ishani M; Vikas, KN; KoKo, Aung; Zaw, Than; Siddhartha, A

    2015-01-01

    Background: Cam femoroacetabular impingement is caused by a misshapen femoral head with a reduced head neck offset, commonly in the anterolateral quadrant. Friction in flexion, adduction and internal rotation causes limitation of the hip movements and pain progressively leading to labral and chondral damage and osteoarthritis. Surgical hip dislocation described by Ganz permits full exposure of the hip without damaging its blood supply. An osteochondroplasty removes the bump at the femoral head neck junction to recreate the offset for impingement free movement. Materials and Methods: Sixteen patients underwent surgery with surgical hip dislocation for the treatment of cam femoroacetabular impingement by open osteochondroplasty over last 6 years. Eight patients suffered from sequelae of avascular necrosis (AVN). Three had a painful dysplastic hip. Two had sequelae of Perthes disease. Three had combined cam and pincer impingement caused by retroversion of acetabulum. All patients were operated by the trochanteric flip osteotomy with attachments of gluteus medius and vastus lateralis, dissection was between the piriformis and gluteus minimus preserving the external rotators. Z-shaped capsular incision and dislocation of the hip was done in external rotation. Three cases also had subtrochanteric osteotomy. Two cases of AVN also had an intraarticular femoral head reshaping osteotomy. Results: Goals of treatment were achieved in all patients. No AVN was detected after a 6 month followup. There were no trochanteric nonunions. Hip range of motion improved in all and Harris hip score improved significantly in 15 of 16 cases. Mean alpha angle reduced from 86.13° (range 66°–108°) to 46.35° (range 39°–58°). Conclusion: Cam femoroacetabular Impingement causing pain and limitation of hip movements was treated by open osteochondroplasty after surgical hip dislocation. This reduced pain, improved hip motion and gave good to excellent results in the short term. PMID

  20. Total hip replacement for high dislocated hips without femoral shortening osteotomy.

    PubMed

    Zhao, X; Zhu, Z-A; Xie, Y-Z; Yu, B; Yu, D-G

    2011-09-01

    When performing total hip replacement (THR) in high dislocated hips, the presence of soft-tissue contractures means that most surgeons prefer to use a femoral shortening osteotomy in order to avoid the risk of neurovascular damage. However, this technique will sacrifice femoral length and reduce the extent of any leg-length equalisation. We report our experience of 74 THRs performed between 2000 and 2008 in 65 patients with a high dislocated hip without a femoral shortening osteotomy. The mean age of the patients was 55 years (46 to 72) and the mean follow-up was 42 months (12 to 78). All implants were cementless except for one resurfacing hip implant. We attempted to place the acetabular component in the anatomical position in each hip. The mean Harris hip score improved from 53 points (34 to 74) pre-operatively to 86 points (78 to 95) at final follow-up. The mean radiologically determined leg lengthening was 42 mm (30 to 66), and the mean leg-length discrepancy decreased from 36 mm (5 to 56) pre-operatively to 8.5 mm (0 to 18) postoperatively. Although there were four (5%) post-operative femoral nerve palsies, three had fully resolved by six months after the operation. No loosening of the implant was observed, and no dislocations or infections were encountered. Total hip replacement without a femoral shortening osteotomy proved to be a safe and effective surgical treatment for high dislocated hips. PMID:21911529

  1. An Unusual Variant of Pipkin's Fracture Dislocation of Hip: A Case Report

    PubMed Central

    Jangir, Rajat; Mishra, Diwakar

    2014-01-01

    Introduction: Injuries of the hip joint from pure hip dislocations to fracture dislocations have been described and classified by various authors. These descriptions do not include fracture dislocation of hip associated with fracture of the greater trochanter. Case Report: We report an unusual case of fracture dislocation of hip in which posterior dislocation of hip was associated with fracture of acetabulum, femoral head, femoral neck, greater trochanter and ipsilateral shaft of tibia. The fracture dislocation was managed with open reduction and internal fixation. Such fracture dislocation has not been reported in literature to the best of our knowledge. Conclusion: We believe that fracture dislocations associate with fractures of greater trochanter should be included in current classification systems of fracture dislocations of hip. PMID:27298974

  2. 21 CFR 890.3665 - Congenital hip dislocation abduction splint.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Congenital hip dislocation abduction splint. 890.3665 Section 890.3665 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices §...

  3. 21 CFR 890.3665 - Congenital hip dislocation abduction splint.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Congenital hip dislocation abduction splint. 890.3665 Section 890.3665 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices §...

  4. 21 CFR 890.3665 - Congenital hip dislocation abduction splint.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Congenital hip dislocation abduction splint. 890.3665 Section 890.3665 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices §...

  5. 21 CFR 890.3665 - Congenital hip dislocation abduction splint.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Congenital hip dislocation abduction splint. 890.3665 Section 890.3665 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices §...

  6. 21 CFR 890.3665 - Congenital hip dislocation abduction splint.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Congenital hip dislocation abduction splint. 890.3665 Section 890.3665 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices §...

  7. [Total hip arthroplasty in the treatment of arthrosis with coexistent high developmental hip dislocation].

    PubMed

    Matewski, Dariusz; Szymkowiak, Edward; Gumański, Ryszard

    2008-01-01

    The question if total hip arthroplasty ought to be advised for patients with high developmental hip dislocation is still actual. The subject of hip arthroplasty, as a method of surgical treatment of high developmental hip dislocation, was analyzed on the base of follow up of seven patients, who underwent this procedure. The mean age of patients was 44.5 (+/- 12.6) years. The mean time of follow up was 64.4 (21.6) months. Initial three patients were treated in two stage regime. In first stage, a surgical hip liberalization and skeletal traction through 3 weeks was performed. In 2nd stage we did total hip replacement with simultaneous shortening of the femoral shaft just below the lesser trochanter. In next four patients we performed total hip arthroplasty with simultaneous shortening of the femoral shaft in one stage. Protection of undesirable rotational instability after osteotomy was done by means of different ways of osteotomy fixation describe in paper. Applied surgical treatment allowed for implanting a cup of prosthesis in original place of acetabulum and reduction of the big anteversion of the femoral neck. The hip congruency was improved in all patients. Score in functional Harris hip scale increased from mean value of 50 points before hip arthroplasty to mean value of 85 points after surgery. The symptoms of late consolidation of osteotomy were observed in one patient with transverse osteotomy without anty-rotational fixation. Total hip replacement with simultaneous "Z" shortening osteotomy of the femoral shaft give good such clinical as radiological results in the treatment of hip osteoarthritis in accordance to high developmental hip dislocation. PMID:18847022

  8. Surgical hip dislocation does not result in atrophy or fatty infiltration of periarticular hip muscles

    PubMed Central

    Glynn, Aaron A.; Barattiero, Fabio Y.; Albers, Christoph E.; Hanke, Markus S.; Steppacher, Simon D.; Tannast, Moritz

    2014-01-01

    Surgical hip dislocation is the gold standard for treatment of femoroacetabular impingement (FAI). It utilizes an intermuscular and internervous approach to the hip. Concerns have been expressed that this approach causes soft tissue trauma resulting in post-operative muscle weakness of patients undergoing this procedure. We therefore asked whether surgical hip dislocation leads to (i) atrophy (decreased muscle diameter or cross-sectional area [CSA]) and (ii) degeneration (fatty infiltration) of 18 evaluated periarticular hip muscles. We retrospectively evaluated 32 patients (34 hips) following surgical hip dislocation for the treatment of FAI using pre and post-operative magnetic resonance (MR) arthrography of the hip. We evaluated muscle diameter, CSA and degree of fatty infiltration according to Goutallier for 18 periarticular hip muscles on axial and sagittal views. The mean interval between pre and post-operative MR was 1.9 ± 1.5 years (range, 0.4–6.1 years). Pre and post-operative muscle diameter and CSA of all 18 evaluated hip muscles did not differ. There was no post-operative change in the Goutallier classification for any of the evaluated 18 muscles. No muscle had post-operative degeneration higher than Grade 1 according to Goutallier. No atrophy or degeneration of periarticular hip muscles could be found following surgical hip dislocation for treatment of FAI. Any raised concerns about the invasiveness and potential muscle trauma for this type of surgery are unfounded. Level III, retrospective comparative study. See guidelines for authors for a complete description of levels of evidence. PMID:27011807

  9. Dislocations

    MedlinePlus

    Dislocations are joint injuries that force the ends of your bones out of position. The cause is often a fall or a blow, sometimes from playing a contact sport. You can dislocate your ankles, knees, shoulders, hips, elbows and jaw. You can also dislocate your finger and toe joints. Dislocated joints often are ...

  10. Impingement and Dislocation in Total HIP Arthroplasty: Mechanisms and Consequences

    PubMed Central

    Brown, Thomas D; Elkins, Jacob M; Pedersen, Douglas R; Callaghan, John J

    2014-01-01

    In contemporary total hip arthroplasty, instability has been a complication in approximately 2% to 5% of primary surgeries and 5% to 10% of revisions. Due to the reduction in the incidence of wear-induced osteolysis that has been achieved over the last decade, instability now stands as the single most common reason for revision surgery. Moreover, even without frank dislocation, impingement and subluxation are implicated in a set of new concerns arising with advanced bearings, associated with the relatively unforgiving nature of many of those designs. Against that backdrop, the biomechanical factors responsible for impingement, subluxation, and dislocation remain under-investigated relative to their burden of morbidity. This manuscript outlines a 15-year program of laboratory and clinical research undertaken to improve the scientific basis for understanding total hip impingement and dislocation. The broad theme has been to systematically evaluate the role of surgical factors, implant design factors, and patient factors in predisposing total hip constructs to impinge, sublux, and/or dislocate. Because this class of adverse biomechanical events had not lent itself well to study with existing approaches, it was necessary to develop (and validate) a series of new research methodologies, relying heavily on advanced finite element formulations. Specific areas of focus have included identifying the biomechanical challenges posed by dislocation-prone patient activities, quantifying design parameter effects and component surgical positioning effects for conventional metal-on-polyethylene implant constructs, and the impingement/dislocation behavior of non-conventional constructs, quantifying the stabilizing role of the hip capsule (and of surgical repairs of capsule defects), and systematically studying impingement and edge loading of hard-on-hard bearings, fracture of ceramic liners, confounding effects of patient obesity, and subluxation-mediated worsening of third body

  11. Total hip arthroplasty in paralytic dislocation from poliomyelitis.

    PubMed

    Laguna, Rafael; Barrientos, Jesús

    2008-02-01

    This article presents a case of a patient with degenerative hip disease in paralytic dislocation by poliomyelitis. Poliomyelitis is an acute infection disease caused by a group of neurotrophic viruses, which has a special affinity by the anterior horns cells of the spinal cord and for certain motor nuclei of the brain stem. Paralysis is a flaccid type and characteristically paralysis is asymmetrical. It is said that the joints of the affected limb by poliomyelitis are protected from the development of osteoarthritis. Hip dislocation in poliomyelitis is an acquired deformity caused by flaccid paralysis and the resulting muscular imbalance. In young children, when the gluteus maximus and medius muscles are paralyzed and the hip flexors and adductors are of normal strength, eventual luxation of the hip is almost inevitable. Hip osteoarthritis in a limb with poliomyelitis is an unusual entity because these limbs do not support excessive loads. In patients who present with the residual effects of poliomyelitis including degenerative disease and hip dysplastic, surgery is one of the most difficult challenges faced by reconstructive surgeons. In such cases, surgeons should attempt to optimize the component position and choice, surgical approach, and soft tissue tensioning because stability of the prosthesis can be problematic. PMID:19292189

  12. Complications of splintage in congenital dislocation of the hip.

    PubMed Central

    Langkamer, V G; Clarke, N M; Witherow, P

    1991-01-01

    The use of abduction splintage in the treatment of congenital dislocation of the hip has an important morbidity. Six children who developed complications are presented in this paper. Sustained splintage of an unreduced hip, overcorrection of the femoral head displacement, avascular necrosis of the femoral head, full thickness pressure sores, and excessive tibial torsion may occur as a consequence of treatment. Expert supervision of abduction splintage, correct case selection, and regular review are necessary to reduce the incidence of such complications. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:1755647

  13. Traumatic bilateral posterior hip dislocation in 10 year old male child.

    PubMed

    Garg, Vipul; Singh, Ajay Pal; Singh, Arun Pal; Bajaj, P S

    2014-09-01

    Traumatic bilateral posterior hip dislocation in skeletally immature patient is reported very less in literature. We report a 10 yr old boy presented to us following farmyard injury with bilateral posterior hip dislocation, which was reduced manually under sedation with uneventful follow-up and complete hip range of motion at 2 year. PMID:25983489

  14. Usefulness of Arthroscopic Treatment of Painful Hip after Acetabular Fracture or Hip Dislocation

    PubMed Central

    Hwang, Jung-Taek; Lee, Woo-Yong; Kang, Chan; Kim, Dong-Yeol; Zheng, Long

    2015-01-01

    Background Painful hip following hip dislocation or acetabular fracture can be an important signal for early degeneration and progression to osteoarthritis due to intraarticular pathology. However, there is limited literature discussing the use of arthroscopy for the treatment of painful hip. The purpose of this retrospective study was to analyze the effectiveness and benefit of arthroscopic treatment for patients with a painful hip after major trauma. Methods From July 2003 to February 2013, we reviewed 13 patients who underwent arthroscopic treatment after acetabular fracture or hip dislocation and were followed up for a minimum of 2 postoperative years. The degree of osteoarthritis based on the Tonnis classification pre- and postoperatively at final follow-up was determined. Clinical outcomes were evaluated using visual analogue scale for pain (VAS) and modified Harris hip score (MHHS), and range of motion (ROM) of the hip pre- and postoperatively at final follow-up. Results There were nine male and four female patients with a mean age at surgery of 28 years (range, 20 to 50 years). The mean follow-up period of the patients was 59.8 months (range, 24 to 115 months), and the mean interval between initial trauma and arthroscopic treatment was 40.8 months (range, 1 to 144 months). At the final follow-up, VAS and MHHS improved significantly from 6.3 and 53.4 to 3.0 and 88.3, respectively (p = 0.002 and p < 0.001, respectively). However, there were no significant differences in hip flexion, abduction, adduction, external rotation, and internal rotation as minor improvements from 113.1°, 38.5°, 28.5°, 36.5°, and 22.7° to 118.5°, 39.0°, 29.2°, 38.9°, and 26.5° were observed, respectively (p = 0.070, p = 0.414, p = 0.317, p = 0.084, and p = 0.136, respectively). None of the patients exhibited progression of osteoarthritis of the hip at the final follow-up. Conclusions Arthroscopic treatment after acetabular fracture or hip dislocation is effective and delays

  15. Cup position alone does not predict risk of dislocation after hip arthroplasty.

    PubMed

    Esposito, Christina I; Gladnick, Brian P; Lee, Yuo-Yu; Lyman, Stephen; Wright, Timothy M; Mayman, David J; Padgett, Douglas E

    2015-01-01

    We used a large prospective institutional registry to determine if there is a 'safe zone' that exists for acetabular component position within which the risk of hip dislocation is low and if other patient and implant factors affect the risk of hip dislocation. Patients who reported a dislocation event within six months after hip arthroplasty surgery were identified, and acetabular component position was measured with anteroposterior radiographs. The frequency of dislocation was 2.1% (147 of 7040 patients). No significant difference was found in the number of dislocated hips among the radiographic zones (±5°,±10°,±15° boundaries). Dislocators <50 years old were less active preoperatively than nondislocators (P=0.006). Acetabular component position alone is not protective against instability. PMID:25249516

  16. Total Hip Arthroplasty Dislocations Are More Complex Than They Appear: A Case Report of Intraprosthetic Dislocation of an Anatomic Dual-Mobility Implant After Closed Reduction

    PubMed Central

    Waddell, Bradford S.; De Martino, Ivan; Sculco, Thomas; Sculco, Peter

    2016-01-01

    Background: Total hip arthroplasty is a successful operation for the treatment of hip pain. One of the common complications of hip arthroplasty is dislocation. While reduction of standard prosthetic dislocations is highly successful, new prostheses add the potential for new complications. Case Report: We present the case of a patient who experienced intraprosthetic dislocation of an anatomic dual-mobility total hip prosthesis after a closed hip reduction and include the prereduction and postreduction radiographic findings. Conclusion: Emergency department physicians should be aware of intraprosthetic dislocation. This complication can be easily missed because the metal/ceramic femoral head appears to be reduced in the acetabulum. PMID:27303232

  17. Asymmetric Bilateral Hip Dislocations: A Case Report and Historical Review of the Literature

    PubMed Central

    Buckwalter, Joseph; Westerlind, Brian; Karam, Matthew

    2015-01-01

    Background Asymmetric bilateral hip dislocations are a rare injury pattern in which one hip dislocates posteriorly, and the contralateral hip dislocates anteriorly. We report a case of bilateral asymmetric hip dislocations and provide a comprehensive review of all available reports, identifying 104 total cases, which is 70 more than previously reported. Purpose To review and evaluate the total body of literature regarding bilateral asymmetric hip dislocations. Methods Comprehensive literature review and analysis of all reports of bilateral asymmetric hip dislocations with concurrent case report. Results and Conclusions Bilateral, asymmetric represent approximately 0.01%–0.02% of all joint dislocations. There has been a substantial increase in the number of case reports in the literature in the last 10 years. Males are more likely than females to incur this injury pattern and the most common mode of injury is motor vehicle accident Urgent closed reduction should be attempted in an efficient and safe manner to avoid potential complications, and open reduction should be considered in irreducible dislocations. Post reduction management should include stability assessment and CT to assess for associated injuries and intraarticular fragments; although no clear guidelines for post-reduction treatment emerged. Common complications include: nerve palsies, AVN and heterotopic ossification. PMID:26361448

  18. Pathogeny and natural history of congenital dislocation of the hip.

    PubMed

    Seringe, R; Bonnet, J-C; Katti, E

    2014-02-01

    Based on a review of the literature, the authors have made a critical study of several etiological factors. Endogenous factors such as acetabular dysplasia, increased anteversion of the femoral neck, and capsular laxity support the genetic theory but are neither constant nor necessary and are only facilitating factors. The major factor seems to be a mechanical one linked to the position in the uterus: hyperflexion with adduction and external rotation constituting the dislocating foetal posture combined with abnormal pressure on the greater trochanter and leading to expulsion of the head upward and backward. This theory can explain the natural history of C D H which is first, at birth a hip instability followed by two possible evolutions: either persistent luxation becoming irreducible or spontaneous stabilisation leading sometimes to complete healing or to residual abnormalities (subluxation or dysplasia). This concept suggests practical conclusions: the importance of an early diagnosis, the selection of the signs of the hip at risk, the pattern of prevention, the role for non-clinical investigations, the principles of the treatment based on postures, the indications for the different types of treatment. PMID:24456762

  19. Capsule repair may reduce dislocation following hip hemiarthroplasty through a direct lateral approach: a cadaver study.

    PubMed

    Hughes, A W; Clark, D; Carlino, W; Gosling, O; Spencer, R F

    2015-01-01

    Reported rates of dislocation in hip hemiarthroplasty (HA) for the treatment of intra-capsular fractures of the hip, range between 1% and 10%. HA is frequently performed through a direct lateral surgical approach. The aim of this study is to determine the contribution of the anterior capsule to the stability of a cemented HA through a direct lateral approach. A total of five whole-body cadavers were thawed at room temperature, providing ten hip joints for investigation. A Thompson HA was cemented in place via a direct lateral approach. The cadavers were then positioned supine, both knee joints were disarticulated and a digital torque wrench was attached to the femur using a circular frame with three half pins. The wrench applied an external rotation force with the hip in extension to allow the hip to dislocate anteriorly. Each hip was dislocated twice; once with a capsular repair and once without repairing the capsule. Stratified sampling ensured the order in which this was performed was alternated for the paired hips on each cadaver. Comparing peak torque force in hips with the capsule repaired and peak torque force in hips without repair of the capsule, revealed a significant difference between the 'capsule repaired' (mean 22.96 Nm, standard deviation (sd) 4.61) and the 'capsule not repaired' group (mean 5.6 Nm, sd 2.81) (p < 0.001). Capsular repair may help reduce the risk of hip dislocation following HA. PMID:25568428

  20. Uncemented total hip arthroplasty in osteoarthritis of hip secondary to low and high dislocated hips: A mid-term follow-up study

    PubMed Central

    Munigangaiah, Sudarshan; O’Dwyer, Sinead; Masterson, Eric

    2016-01-01

    Background: Performing successful total hip replacement (THR) in dysplastic, subluxed, and dislocated hip is a challenging task. Here, we assessed midterm clinical and radiological outcomes of uncemented total hip arthroplasty in osteoarthritis (OA) of hip secondary to Hartofilakidis low and high-dislocated hips with a mean follow-up of 8.8 years. Materials and Methods: A retrospective study of prospectively collected data was designed involving all consecutive patients who underwent uncemented THR for OA of hip secondary to developmental dysplasia of the hip and Grade II or Grade III Hartofilakidis classification. Results: Thirty-two patients underwent 45 THR, with 23 Grade II (low dislocation) and 22 Grade III (high-dislocation) of Hartofilakidis classification. Thirteen patients had bilateral hip replacements, 19 patients had unilateral THR. There was highly statistically significant difference between preoperative and postoperative HHS and SF-36v2™ at each follow-up. Survivorship of original implant was 98.88% at a mean follow-up of 8.8 years. The mean improvement in leg length in this series was 3.6 cm (1.8-4.5, 95% confidence interval). No sciatic nerve or femoral nerve palsies were observed. Conclusions: Uncemented THR provides better function and quality of life. However, longer follow-up studies are needed to assess survivorship of uncemented THR in Hartofilakidis low and high-dislocations. PMID:27433063

  1. Epidemiology of traumatic hip dislocation in patients treated in Ceará, Brazil

    PubMed Central

    Lima, Luciana Cascão; do Nascimento, Robson Alves; de Almeida, Victor Monte Tenório; Façanha, Fernando Antônio Mendes

    2014-01-01

    OBJECTIVE: To describe the epidemiological profile of patients with traumatic hip dislocation treated in our Institute from November/2012 to July/2013. METHODS: A descriptive cross-sectional study based on interviews and involving 43 patients who suffered traumatic hip dislocation was conducted. RESULTS: The mean age of patients was 34.4 years old and 90.7% were male. Regarding the mechanism of injury, 95% involved traffic accidents. The posterior dislocation of the hip was the most common injury (93%). Associated lesions were observed in 74.4% of patients, hip fractures being the most frequent. The time span between accident and dislocation reduction was less than 6 hours in 37.2% of patients, between 6 and 12 hours in 32.5% and over 12 hours in 30.3%, ranging from 1 hour to 15 days. A fraction of 90.7% of patients was submitted to closed reduction. CONCLUSION: Traumatic hip dislocation affected mostly young adults, victims of traffic accidents. The posterior dislocation of the hip was the most frequent injury and closed reduction was performed in 90.7% of patients. The time span between accident and dislocation reduction was less than 12 hours in most patients. Level of Evidence III, Study of Nonconsecutive Patients. PMID:25061422

  2. Inferior dislocation of the hip: a case report and literature review.

    PubMed

    Jain, Sameer; Haughton, Benjamin A; Grogan, Richard J

    2015-04-01

    We report on a 17-year-old man who underwent open reduction and internal fixation for an inferior dislocation of the right hip and displaced fractures of the right femoral head and neck, and antegrade intramedullary nailing for a displaced fracture of the left femoral shaft. In addition, 13 men and 4 women aged 5 to 56 (mean, 23) years with 16 unilateral and one bilateral inferior dislocation of the hip were reviewed from the literature. PMID:25920660

  3. Management of dislocated hips with Pavlik harness treatment and ultrasound monitoring.

    PubMed

    Harding, M G; Harcke, H T; Bowen, J R; Guille, J T; Glutting, J

    1997-01-01

    We studied the outcome of ultrasound-monitored Pavlik harness treatment of 47 infants (nine boys and 38 girls) with 55 frankly dislocated hips documented by dynamic ultrasonography. The success and failure groups were of similar ultrasound status (hip-status score) at the time of initial examination, but a significant difference emerged at the 7- and 14-day examinations. Detection of frank dislocation and institution of treatment with the Pavlik harness within 3 weeks of birth increased the probability of a successful result. Of 33 infants (27 girls and six boys) with 41 dislocated hips who were seen before the age of 21 days, 26 (63%) hips were reducible in the Pavlik harness alone, and 15 (37%) hips were irreducible and required a subsequent procedure to achieve reduction. Fourteen infants (three boys and 11 girls) with 14 dislocated hips were first seen after the age of 21 days. Three (20%) were successfully treated in the Pavlik harness alone, and 11 (80%) required further treatment. In our opinion, persistent dislocation without improvement after 3 weeks of treatment in the Pavlik harness mandates discontinuation of use of this device. No anatomic factors were seen at the time of the initial ultrasound examination that permitted prediction of those hips likely to succeed or fail treatment with the Pavlik harness. PMID:9075094

  4. Unconstrained tripolar implants for primary total hip arthroplasty in patients at risk for dislocation.

    PubMed

    Guyen, Olivier; Pibarot, Vincent; Vaz, Gualter; Chevillotte, Christophe; Carret, Jean-Paul; Bejui-Hugues, Jacques

    2007-09-01

    We performed a retrospective study on 167 primary total hip arthroplasty (THA) procedures in 163 patients at high risk for instability to assess the reliability of unconstrained tripolar implants (press-fit outer metal shell articulating a bipolar polyethylene component) in preventing dislocations. Eighty-four percent of the patients had at least 2 risk factors for dislocation. The mean follow-up length was 40.2 months. No dislocation was observed. Harris hip scores improved significantly. Six hips were revised, and no aseptic loosening of the cup was observed. The tripolar implant was extremely successful in achieving stability. However, because of the current lack of data documenting polyethylene wear at additional bearing, the routine use of tripolar implants in primary THA is discouraged and should be considered at the present time only for selected patients at high risk for dislocation and with limited activities. PMID:17826276

  5. [Dislocation of the hip in a patient with von Recklinghausen disease].

    PubMed

    Del Bosque-Herrero, A; Ezquerra-Herrando, L; Albareda-Albareda, J

    2014-01-01

    Neurofibromatosis type 1 (NF-1) is one of the most common autosomal dominant disorders affecting humans. Patients with NF-1 may present with characteristic orthopaedic manifestations such as scoliosis, congenital pseudoarthrosis and limb hyperttrophy. Dislocation of the hip associated with NF-1 is a rare occurrence. There is a relative paucity of reported cases of pathological hip dislocation in patients with NF-1, with 13 documented cases found in the published literature. Seven dislocations occurred following trivial trauma and 6 cases were deemed atraumatic. We report a case of hip dislocation in a 26 years old male with NF-1 and scoliosis, that was treated successfully by closed reduction and skin traction. PMID:24094733

  6. A reduction technique of arthroplasty without subtrochanteric femoral shortening osteotomy for the treatment of developmental high dislocation of hip: a case series of 28 hips.

    PubMed

    Yan, Fei; Chen, Guangxing; Yang, Liu; He, Rui; Gu, Lingchuan; Wang, Fuyong

    2014-12-01

    In total hip arthroplasty for the treatment of developmental dysplasia of the hip (DDH) with high hip dislocation, it can be technically challenging to locate the true acetabulum and restore limb length without subtrochantric femoral shortening osteotomy. We explored and described total hip arthroplasty without subtrochanteric femoral shortening osteotomy in 28 hips with Crowe type III and IV dislocation by intravenous injection of rocuronium at 0.9mg/kg 1minute before reduction and hip reduction combined with continuous strong traction of the affected limb with patients in a position with hip and knee flexion. All patients did not show dislocation, prosthesis loosening, and other severe complications. It is thus a safe and feasible reduction technique for arthroplasty of Crowe type III or IV dislocation of DDH. PMID:24412147

  7. Modular noncemented total hip arthroplasty for congenital dislocation of the hip. Case report and design rationale.

    PubMed

    Gorski, J M

    1988-03-01

    The highest rate of failure and the greatest technical difficulty in total hip arthroplasty occurs with congenital dislocation of the hip (CDH). Predisposing factors are failure to secure special femoral components to fit an extremely narrow and straight medullary cavity with space for only a very thin mantle of cement. The acetabulum is usually atrophic, and bone grafts are commonly required to support a small-diameter cup. The young age of the average patient and high levels of activity contribute to cement failure. A new modular cementless prosthesis provides excellent immediate skeletal fixation and pain relief in CDH patients. Five modular components are screwed or press-fit into bone. The modular approach facilitates implantation, reduces inventory, and is adaptable to unforeseen problems. These advantages are ordinarily absent with standard or custom cemented components. Modular components may also permit easier revision. The prosthesis is made of titanium alloy for its superalloy strength, elastic modulus, and bioinertness. By omitting the cement mantle, press-fit is obtained with the largest possible implant. The large size minimizes stem breakage in these young, small bones. Excellent short-term results suggest that modular cementless implants are indicated in some patients with CDH. PMID:3342552

  8. Prevention of congenital dislocation of the hip. The Swedish experience of neonatal treatment of hip joint instability.

    PubMed

    Palmén, K

    1984-01-01

    The extensive work on early diagnosis and treatment of CDH (in the broad sense of this term) in Sweden has formed the basis of our present organization of prevention of hip dislocation. Practically all children are born in hospital, at present about 93,000 per year (1980). Routine examination of the hip joints has been included in the check-ups of newborns since the beginning of the 1950's. The centralization of obstetrics, especially during the last decade, has facilitated the organization of these examinations by paediatric consultants in all obstetric departments. All cases of hip joint instability are recorded, and during the last few years the frequency has been about 12 per thousand, probably with some over-diagnosis due to registration of uncertain cases. All definite cases of hip instability have been treated immediately at the orthopaedic departments. A study of a series of untreated newborns with transient instability has shown that the majority, but not all, will develop normal hip joints without treatment. This has been one reason for the recommendation to treat all unequivocal cases of hip instability. The present organization of examination and treatment is described. Detailed and practical instructions for the examination and treatment are given. Follow-ups of children treated for hip instability in the neonatal period are reported. It has been found that in practically all these patients anatomically normal hip joints are achieved by means of correct and carefully followed up treatment. The findings in 65 patients with neonatal hip instability in whom the treatment was unsuccessful or inadequate have underlined the importance of a strict treatment schedule, experienced doctors and detailed information to the parents. The effect of diagnosis and treatment of hip instability neonatally on the frequency of late-diagnosed cases of CDH was studied by recording all late-diagnosed cases at all orthopaedic departments. It was clear from the latter study

  9. Anterior Hip Fracture Dislocation with Intrapelvic Retention of the Femoral Head and Ureter Fistula

    PubMed Central

    Patrascanu, Calin; Cibu, Dan

    2014-01-01

    Introduction: The anterior dislocation of the hip represents only a small percentage of all hip dislocations: 85% are posterior. Most commonly associated with this dislocation is a fracture of the femoral head and, in rare cases, a femoral neck fracture. We have found in literature no report of an anterior dislocation of the hip associated with femoral neck fracture, pelvic retention of the head and ureteral fistula. We report such a case of a 68 year old male. Case Report: A 68 year old male was presented to our attention, following a severe injury of the hip when falling from a high bridge, with severe pain in the hip and a clinical aspect of femoral neck fracture. The X-ray confirmed the femoral neck fracture but following an anterior dislocation with the head retained into the pelvis. The patient also had hematuria. An Austin Moore prosthesis was implanted for the femoral neck fracture and the head was extracted by the urologist by a new abdominal incision. Urological evaluation revealed a fistula of the ureter, treated by an internal drainage for three months. One month later the Moore prosthesis was extracted and the patient had a Girldestone hip for 5 months. Revision with a Muller cemented prosthesis had a normal evolution. Conclusion: The anterior fracture dislocation of the hip with pelvic retention of the femoral head and ureteral fistula is a rare condition resulting from high energy trauma. A multidisciplinary team is necessary to diagnose and treat fracture and soft tissue lesions. Early diagnosis and treatment is necessary to avoid septic complications. PMID:27298980

  10. Clinical outcome of Zweymüller total hip arthroplasty for patients with high congenital hip dislocation.

    PubMed

    Chen, Dongyang; Xu, Zhihong; Shi, Dongquan; Qiu, Xusheng; Dai, Jin; Yuan, Tao; Weng, Wenjie; Jiang, Qing

    2011-01-01

    Treatment of high congenital dislocation of the hip (CDH) remains controversial. We report the outcome of hip arthroplasty using a cementless threaded cup and a cementless straight stem in patients with high congenital hip dislocation. Between January 2001 and August 2004, 17 patients with high congenital hip dislocation were treated. During surgery, at least 25% of the cup was anchored in bone. By monitoring somatosensory-evoked potentials (SEPs) of the common peroneal nerve we were able to reduce the femoral head into position in the true acetabulum by releasing soft tissues. A bulk autogenous femoral head bone graft was implanted in 5 patients to achieve at least 75% bony coverage of the acertabular component. Follow-up ranged from 48 months to 91 months with an average of 69.7 months. The mean Harris hip score increased from 43 points preoperatively to 89 points at the time of final follow-up (P<0.001). Radiographic analysis showed bony union of the bone graft in all cases. PMID:21279967

  11. Chronic Lymphedema of the Lower Limb: A Rare Cause of Dislocation of Total Hip Arthroplasty

    PubMed Central

    Vaishya, Raju; Gupta, Nishint; Vijay, Vipul

    2016-01-01

    Total hip arthroplasty (THA) in a patient with chronic lymphedema of both lower limbs is rarely reported in the literature. Chronic lymphedema is a challenging condition associated with various complications especially in a patient with THA. However, dislocation of the total hip prosthesis due to acute exacerbation of lower limb swelling in the postoperative period is an extremely rare complication. The cause that led to the dislocation of the prosthesis is intricate and difficult to assess, as this has not been discussed in the literature yet. We believe that the excessive weight of the limb due to chronic lymphedema had a deleterious effect on the biomechanics of total hip prosthesis, thereby increasing the tendency for dislocation. This case illustrates that chronic lymphedema of the lower limb should be dealt with aggressively using various modalities like intermittent pneumatic compression pumps and compression stockings after THA in such patients. PMID:27226940

  12. Chronic Lymphedema of the Lower Limb: A Rare Cause of Dislocation of Total Hip Arthroplasty.

    PubMed

    Vaishya, Raju; Agarwal, Amit Kumar; Gupta, Nishint; Vijay, Vipul

    2016-01-01

    Total hip arthroplasty (THA) in a patient with chronic lymphedema of both lower limbs is rarely reported in the literature. Chronic lymphedema is a challenging condition associated with various complications especially in a patient with THA. However, dislocation of the total hip prosthesis due to acute exacerbation of lower limb swelling in the postoperative period is an extremely rare complication. The cause that led to the dislocation of the prosthesis is intricate and difficult to assess, as this has not been discussed in the literature yet. We believe that the excessive weight of the limb due to chronic lymphedema had a deleterious effect on the biomechanics of total hip prosthesis, thereby increasing the tendency for dislocation. This case illustrates that chronic lymphedema of the lower limb should be dealt with aggressively using various modalities like intermittent pneumatic compression pumps and compression stockings after THA in such patients. PMID:27226940

  13. Fracture of the Greater Trochanter during Closed Reduction of Obturator Type Hip Dislocation

    PubMed Central

    Yang, Jae-Hyuk; Pandher, Dilbans Singh

    2014-01-01

    Obturator (Inferior) type dislocation of the hip joint is a rare and the fracture of greater trochanter during closed reduction for it has never been reported in literature. In this report, we present a case of a fracture of greater trochanter during difficult closed reduction which required operative fixation. Surgeons need to be aware of this complication and excessive force for reduction should be avoided when treating of this type dislocation.

  14. Treatment of Hip Dislocations and Associated Injuries: Current State of Care.

    PubMed

    Beebe, Michael J; Bauer, Jennifer M; Mir, Hassan R

    2016-07-01

    Hip dislocations, most often caused by motor vehicle accidents or similar high-energy trauma, traverse a large subset of distinct injury patterns. Understanding these patterns and their associated injuries allows surgeons to provide optimal care for these patients both in the early and late postinjury periods. Nonoperative care requires surgeons to understand the indications. Surgical care requires the surgeon to understand the benefits and limitations of several surgical approaches. This article presents the current understanding of hip dislocation treatment, focusing on anatomy, injury classifications, nonoperative and operative management, and postinjury care. PMID:27241377

  15. [Dislocation after total hip arthroplasty--the problem is still present, reasons and treatments].

    PubMed

    Pepłoński, Artur; Płomiński, Janusz

    2014-03-01

    Dislocation after total hip replacement remains a significant problem in orthopedic practice. Despite the use of more modem implants risk of instability is estimated at a few percent for primary treatment and for several procedures. The standard procedure in case of the first dislocation is reduction of the prosthesis in general anesthesia. Further investigation is individual, each case must be thoroughly examined for proper execution of the original surgery and the risk of the next dislocation. Regardless of the subsequent procedures performed a key role in the event of instability prosthesis plays properly conducted rehabilitation and patient education. PMID:24779210

  16. Relation Between Side of Plagiocephaly, Dislocation of Hip, Scoliosis, Bat Ears, and Sternomastoid Tumours

    PubMed Central

    Watson, Geoffrey H.

    1971-01-01

    A relation is described between plagiocephaly and four structural lesions in children who have two or more of these five features. The flat temple in plagiocephaly, a unilateral congenitally dislocated hip, a scoliotic convexity in a young child, and a sternomastoid tumour tend to be on the same side, and a unilateral bat ear on the opposite side. PMID:5576031

  17. [Preliminary treatment of congenital hip dislocation using physical therapy based on neurophysiology].

    PubMed

    Niethard, F U

    1987-01-01

    Adductor tightness is a typical symptom in CDH. In cases of subluxation and complete dislocation even a rigid abduction contracture can occur, preventing reduction and favouring redislocation. The contracture of the hip joint is the result of neurophysiological disorders, which can be treated by an exercise program on a neurophysiological basis. 62 children with 73 severely contracted and 5 hypotonic hip dislocations have been treated by the so-called "Vojta-program" before reduction. In a prospective study over 5 years this kind of treatment has been very successful: the incidence of necrosis of the femoral head could be reduced to 4%, long-lasting traction was not necessary anymore and the rigid hip joints required open reduction only in 2 cases. PMID:3577341

  18. Ipsilateral obturator type of hip dislocation with fracture shaft femur in a child: a case report and literature review.

    PubMed

    Arjun, R H H; Kumar, Vishal; Saibaba, Balaji; John, Rakesh; Guled, Uday; Aggarwal, Sameer

    2016-09-01

    The incidence of traumatic hip dislocations in children is rising in this fast developing world along with increasing numbers of high-velocity road traffic accidents. Anterior dislocation of the hip has a lower incidence compared with posterior dislocation of the hip. We encountered a rare case of the obturator type of anteriorly dislocated hip associated with ipsilateral fracture of the shaft femur in an 11-year-old child. This is a highly unusual injury combination and the mechanism of injury is obscure. Only two similar cases have been reported in the English literature to date. Closed reduction of the hip using a hitherto undescribed technique and an intramedullary interlocking nail was performed in this case. At 6 months of follow-up, the fracture shaft femur has united and the child is bearing full weight on the limb. PMID:27128394

  19. [Nonarthroplasty methods for developmental dysplasia of the hip with complete dislocation at the age of 8-25 patients].

    PubMed

    Zang, Jiancheng; Zhang, Hong

    2015-06-01

    It is a tough challenge treatment of complete dislocation from developmental dysplasia of the hip at the age of 8-25 patients. Although the procedure of total hip arthroplasty (THA) can improve joint function significantly, the failure rate still remains high. Hip arthrodesis remains a sensible and safe option. A stable and painless hip joint can be obtained without multiple operations. Ganz et al.had described a modified Colonna capsular arthroplasty and surgical hip dislocation with well joint functions, radiographic findings and the less complications of the femoral head osteonecrosis. There is a obvious advantage in postponing THA, and subsequent THA could be technically easier and safer in a dislocated hip. The procedure of pelvic support osteotomy, which is proposed by Ilizarov, combined two steps of femur osteotomy and femur lengthening, provides an effective treatment option for adolescent hip dysplasia or dislocation. By this procedure, the hip could be reserved, the limb length recovered and the gait improved significantly. Resection arthroplasty is a reliable method, by which 90% dysplasia patients received a painless joint and good functional outcomes. In view of certain drawbacks, it is used only as a salvage operation currently. This article reviews some alternative nonarthroplasty methods for developmental dysplasia of the hip with complete dislocation. Good clinical results can be obtained through strict indications and nice surgical skills. PMID:26359064

  20. A national survey of screening for congenital dislocation of the hip.

    PubMed Central

    Dezateux, C; Godward, S

    1996-01-01

    OBJECTIVE: To identify current screening and management practices for congenital dislocation of the hip (CDH), and determine the extent to which ultrasound imaging of the hips is practised throughout the United Kingdom and the Irish Republic. METHODS: Postal questionnaire to paediatricians responsible for the routine neonatal care of infants in all maternity units in the UK and the Irish Republic. RESULTS: Questionnaires were returned for 254 maternity units (92% response rate). By 1994, 69% of maternity units had access to ultrasound imaging of the hips, compared to 14% in 1984. Ultrasound imaging of the hip was not used for universal primary screening, but in 93% of units was undertaken for further assessment of infants with clinically detected hip instability or those identified as being at high risk of CDH, or both. Clinical screening of newborn infants was performed by junior paediatricians, but training with a 'Baby Hippy' hip simulator model was provided in only 37% of units. Treatment of clinically detected hip instability, initiated by an orthopaedic surgeon in 93% of units, varied widely in type and duration. CONCLUSIONS: Ultrasound imaging of the hip is increasingly used in the UK for secondary, rather than primary, screening. Current recommendations are implemented to a variable extent nationally, and the existing wide variation in screening and management for CDH reflects a lack of research evidence to support current screening practices. The effectiveness of screening for CDH needs to be established. PMID:8669963

  1. Late Anterior Dislocation Due to Posterior Pelvic Tilt in Total Hip Arthroplasty

    PubMed Central

    Kobayashi, Hiroki; Nakashima, Yasuharu; Yamamoto, Takuaki; Motomura, Goro; Kanazawa, Masayuki; Takagishi, Kenji; Iwamoto, Yukihide

    2016-01-01

    Background: Excessive pelvic tilt may be one of the factors leading to instability in total hip arthroplasty (THA), even when the acetabular cup is placed properly. To our knowledge, only a few studies have described late anterior dislocation due to posterior pelvic tilt. We present 3 cases with late anterior dislocations possibly due to posterior pelvic tilt. Cases Presentations: Case-1: An 84-years-old woman fell and presented with an anterior dislocation 12-years after THA. Her pelvis had tilted to approximately 30° posteriorly in a supine position. After conservative treatment, she presented with 10 recurrent anterior dislocations. She had thoracolumbar kyphosis due to multiple compression fractures. Revision with anterior placement of an elevated liner and a 32-mm head corrected the dislocation, and no further dislocations occurred. Case-2: A 78-years-old woman fell and presented with an anterior dislocation 4-years after THA. Her posterior pelvic tilt had increased 23° due to a lumbar compression fracture. Revision by decreasing the cup anteversion was performed, but recurrent posterior dislocations occurred. Owing to her worsened general condition, further treatment was abandoned. Case-3: A 79-years-old woman twisted her body and presented an anterior dislocation 3-years after THA. After manual reduction and conservative treatment, the dislocation recurred. Her posterior pelvic tilt had increased 16°. Conclusion: Although minor trauma triggered the anterior instability in these patients, the underlying pathomechanism existed in the progressive pelvic posterior tilt due to thoracolumbar kyphosis. As longer life expectancy as well as implant survivorship is predicted, attention must be paid to the change of pelvic tilt in elderly patients. PMID:27398108

  2. Dislodgement of a cemented exeter femoral stem during closed manipulative reduction of a dislocated total hip replacement

    PubMed Central

    Rajeev, Aysha; Mohamed, Abdalla; Shaikh, Mazharuddin; Banaszkiewicz, Paul

    2016-01-01

    Introduction The incidence of cemented femoral stem migration and dislodgement even though has been described is extremely unusual. There is a high chance of polished femoral stem displacement happening while trying to reduce a dislocated total hip replacement by closed measures. Presentation of the case A 73 year old lady who had an Exeter cemented total hip replacement about two weeks back was admitted from Accident and Emergency with a dislocation. During the closed manipulative reduction under general anaesthesia it was noted that the femoral stem has dislodged from the canal. She underwent revision of the total hip replacement with good outcome. Discussion Femoral stem dislodgement occurs in total hip replacement if polished stem or inadequate cementing of the collar is carried out. Conclusion Gentle manipulative reduction under general anaesthesia of dislocated total hip replacement should be carried out if the polished femoral stem is used. PMID:27060643

  3. Automatic Measurement System For Congenital Hip Dislocation Using A Computed Radiography

    NASA Astrophysics Data System (ADS)

    Komori, M.; Minato, K.; Nakano, Y.; Hirakawa, A.; Kuwahara, M.

    1988-06-01

    Acetabular angle which is a diagnostic parameter of congenital hip dislocation has been measured manually in conventional X-ray film system. Using digital image directly provided from a computed radiography, an automatic measurement system was developed for this parameter. The process of the measurement was completed within a reasonable time, and accurate enough. The system was combined with an image database, so that it would be a measurement tool of PACS.

  4. Pseudo-Acetabulum due to Heterotopic Ossification in a Child with Post Traumatic Neglected Posterior Hip Dislocation

    PubMed Central

    Pathak, Aditya C; Patil, Atul K; Sheth, Binoti; Bansal, Rohan

    2012-01-01

    Introduction: Traumatic neglected dislocations of hip in children are rare entity. Neglected traumatic dislocations of hip in children along with heterotopic ossification are still rare. Post traumatic neglected hip dislocations are to be diagnosed as early as possible and have to be treated with precision and aggression as the outcome of treatment for the same is not predictable. Case Report: 5 year female with post-traumatic neglected hip dislocation with heterotopic ossification forming a pseudoacetabulum postero-superiorly in which femur head was lodged. The girl was operated by open reduction using Moore’s Posterior approach and showed good results. Here is a mention of a rare case with a good 18 months follow up with no complication. Conclusions: Post-traumatic neglected posterior hip dislocation mostly requires open reduction and relocation of femoral head in original acetabulum with concentric reduction. Heterotopic ossification is a rare but known complication of traumatic dislocation of hip in children. Good results can be achieved in such cases and regular follow-up of patient is required post-operatively.

  5. Unilateral Congenital Knee and Hip Dislocation with Bilateral Clubfoot - A rare Packaging disorder

    PubMed Central

    Tiwari, Mukesh; Sharma, Nishith

    2013-01-01

    Introduction: Reduced intrauterine space gives rise to ‘packaging disorder’ which may involve joint dislocations or contractures. We present an unique case where mutiple joints were dislocated involving left congenital knee dislocation (CDK), bilateral congenital hip dislocation (CDH) and congenital talipes equino varus (CTEV)deformities. Case Report: A preterm baby boy born to mother with diagnosed oligohydramios presented with left CDK bilateral DDH and CTEV. The knee dislocation was treated first with gradual streaching and weekly above knee cast. At 7th week good flexion was achieved at both knees and abduction splint for DDH (using double diaper) with ponseti cast for CTEV was done. At one year follow up all joints were reduced and maintained well with baby able to stand with support. Conclusion: Packaging disorders may present with multiple dislocations and deformities. Early intervention with serial casting and manipulation minimises disability and prevents ambulatory problems. In our case there was a good response to manipulation and serial casting. This differs from cases with inherent pathology like arthrogryposis where response to treatment is not so good PMID:27298901

  6. Dislocation of a dual mobility total hip replacement following fracture of the polyethylene liner.

    PubMed

    Vedrine, Bertrand; Guillaumot, Pierre; Chancrin, Jean-Luc

    2016-05-18

    An eight-year-old male English Setter was referred for management of a dislocation of a cemented dual mobility canine total hip prosthesis that occurred four months after the initial surgery. Revision surgery showed that the dislocation was associated with fracture of the ultra-high molecular weight polyethylene liner. The dislocation was successfully reduced after replacing the liner. A dual mobility acetabular component is composed of a mobile polyethylene liner inside a metallic cemented cup. Chronic wear of the components of a canine dual mobility total hip replacement has not been described previously. The use of this type of implant is fairly recent and limited long term follow-up of the implanted cases may be the explanation. Acute rupture of a polyethylene liner has never been described in humans, the only case of rupture of a polyethylene liner occurred 10 years after implantation. The case presented here of rupture of the polyethylene liner of a dual mobility total hip replacement is a hitherto unreported failure mode in this model of acetabular cup in the dog. PMID:26991949

  7. TRAUMATIC POSTERIOR DISLOCATION OF THE HIP IN CHILDREN:REPORT ON FIVE CASES

    PubMed Central

    Brandão, Gilberto Francisco; Américo, Luiz Renato Drumond; Soares, Cláudio Beling Gonçalves; Faria, Rodrigo Galinari Costa; Teixeira, Luiz Eduardo Moreira

    2015-01-01

    Objective: To evaluate a series of cases of traumatic posterior dislocations in children, with the treatment and results, and to review issues relating to the epidemiology, clinical and radiographic diagnosis, treatment, complications and prognosis of such cases. Methods: Five patients with traumatic hip dislocation, with a mean age of 4.6 ± 0.9 years and a follow-up period of 19.8 ± 7.0 months, were evaluated retrospectively. The time elapsed between dislocation and reduction, the type of treatment, the associated injuries and the subsequent complications were evaluated. Results: The initial treatment was closed reduction, which was performed on average 5.2 ± 3.6 hours after the initial trauma. All the patients underwent the reduction under anesthesia. The complementary treatment included plaster cast immobilization and traction. No need for additional surgery was observed and there were no long-term side effects. Conclusion: Traumatic dislocation of the hip should be treated quickly by means of closed reduction, with appropriate control over the reduction and rigorous observation in order to diagnose and treat late complications. PMID:27022542

  8. Surgical dislocation of the hip for the fixation of acetabular fractures.

    PubMed

    Tannast, M; Krüger, A; Mack, P W; Powell, J N; Hosalkar, H S; Siebenrock, K A

    2010-06-01

    Surgical dislocation of the hip in the treatment of acetabular fractures allows the femoral head to be safely displaced from the acetabulum. This permits full intra-articular acetabular and femoral inspection for the evaluation and potential treatment of cartilage lesions of the labrum and femoral head, reduction of the fracture under direct vision and avoidance of intra-articular penetration with hardware. We report 60 patients with selected types of acetabular fracture who were treated using this approach. Six were lost to follow-up and the remaining 54 were available for clinical and radiological review at a mean follow-up of 4.4 years (2 to 9). Substantial damage to the intra-articular cartilage was found in the anteromedial portion of the femoral head and the posterosuperior aspect of the acetabulum. Labral lesions were predominantly seen in the posterior acetabular area. Anatomical reduction was achieved in 50 hips (93%) which was considerably higher than that seen in previous reports. There were no cases of avascular necrosis. Four patients subsequently required total hip replacement. Good or excellent results were achieved in 44 hips (81.5%). The cumulative eight-year survivorship was 89.0% (95% confidence interval 84.5 to 94.1). Significant predictors of poor outcome were involvement of the acetabular dome and lesions of the femoral cartilage greater than grade 2. The functional mid-term results were better than those of previous reports. Surgical dislocation of the hip allows accurate reduction and a predictable mid-term outcome in the management of these difficult injuries without the risk of the development of avascular necrosis. PMID:20513883

  9. [Clinical and ultrasonic diagnosis of congenital hip dislocation (dynamics of changes in early therapy)].

    PubMed

    Poul, J; Procházka, J; Klimsová, J; Janovec, M; Bajerová, J; Jíra, I; Straka, M; Sommernitz, M

    1990-08-01

    The authors present part of their prospective epidemiological study of congenital dysplasia of hip joints within which newborns were examined by ultrasonogram prior to the beginning of the therapy. Apart from the standard examination in the frontal plane after Graf they examined on principle also the ultrasonographic stability by the dynamic test after Schuler as well as by the application of the probe anteriorly with the simultaneous provocation according to Palmén. The authors have processed pathological ultrasonographic findings in 53 newborns (64 hip joints). The technique of the examination by ultrasound from the anterior approach is explained in detail. The comparison of both dynamic tests has shown that the examination from the anterior approach is considerably more sensitive than Schuler's dynamic test and also fully correlates with the clinical finding. It is a fact that the shift of the head in the flexion dorsally represents the most important component of the movement in unstable hip joint during provocation, it is far more noticeable than the lateralization of the head or the shift in the cranial direction. After achieving ultrasonographic stability the classical Graf method is sufficient for the registration of residual changes on the acetabular rim. The follow-up of patients until their complete healing has shown a surprisingly rapid remodellation of hip joints. The whole complex of clinically unstable hip joints has been divided into subgroups according to Graf classification. In type IIc or IId on the basis of ultrasonographic examination from the anterior approach the stable joints from the ultrasonographic viewpoint have been distinguished from unstable ones. The follow-up carried out in short intervals has shown that of longest duration is the remodellation of total dislocation and, on the contrary, of shortest duration is the healing of joints in the IIc or IId type. An absolute majority of affected hip joints have become normal until 3rd

  10. Surgical hip dislocation in symptomatic cam femoroacetabular impingement: what matters in early good results?

    PubMed Central

    2011-01-01

    In order to assess outcome and possible predictors of early good results, a prospective study on 22 patients who were treated with save surgical hip dislocation for symptomatic isolated cam-type femoroacetabular impingement (FAI) was performed. After a follow-up of 6 and 12 months, standard clinical and radiographic parameters were recorded. A statistically significant improvement of the clinical status according to the Harris hip score could be assessed at six months (p-value = 0.003) and 12 months (p-value = 0.001) post-surgery. By comparing standard clinical and radiographic preoperative parameters with various follow-up outcomes, we revealed no specific parameter with predictive value. These findings are important for centers that have just started to use this surgical technique and are still identifying their learning curve. PMID:21719395

  11. Surgical hip dislocation in symptomatic cam femoroacetabular impingement: what matters in early good results?

    PubMed

    Jäger, M; Bittersohl, B; Zilkens, Christoph; Hosalkar, H S; Stefanovska, K; Kurth, S; Krauspe, R

    2011-05-12

    In order to assess outcome and possible predictors of early good results, a prospective study on 22 patients who were treated with save surgical hip dislocation for symptomatic isolated cam-type femoroacetabular impingement (FAI) was performed. After a follow-up of 6 and 12 months, standard clinical and radiographic parameters were recorded. A statistically significant improvement of the clinical status according to the Harris hip score could be assessed at six months (p-value = 0.003) and 12 months (p-value = 0.001) post-surgery. By comparing standard clinical and radiographic preoperative parameters with various follow-up outcomes, we revealed no specific parameter with predictive value. These findings are important for centers that have just started to use this surgical technique and are still identifying their learning curve. PMID:21719395

  12. Hip CT in congenital dislocation: appearance of tight iliopsoas tendon and pulvinar hypertrophy

    SciTech Connect

    Hernandez, R.J.; Tachdjian, M.O.; Dias, L.S.

    1982-08-01

    The iliopsoas tendon can interpose between the femoral head and the acetabulum, preventing reduction or stability of reduction of a dislocated hip by a closed method. The tendon produces an infolding of the capsule and labrum. This infolding of the capsule and labrum creates an ''isthmus'' between the capital and the acetabular parts of the capsule. This deformity of the capsule was recognizable on computed tomography (CT) in 10 patients, all of whom had surgical confirmation of the findings. The presence of hypertrophied pulvinar can also be recognized by CT.

  13. Dislocation

    MedlinePlus

    Joint dislocation ... It may be hard to tell a dislocated joint from a broken bone . Both are emergencies. You ... to repair a ligament that tears when the joint is dislocated is needed. Injuries to nerves and ...

  14. Utilization of the safe surgical dislocation approach of the hip to retrieve a bullet from the femoral head.

    PubMed

    Delaney, Ruth; Albright, Maurice; Rebello, Gleeson

    2011-01-01

    Retained intra-articular missiles from low-velocity handguns can lead to mechanical arthritis, synovitis, and lead toxicity. Various surgical approaches have been described to extract such foreign bodies from the hip joint. We present the case of a 17-year-old male in which the surgical dislocation approach was utilized to retrieve a bullet from the femoral head with a good short-term outcome. This case represents a rare application of the surgical hip dislocation approach for an unusual trauma. PMID:23198205

  15. Concomitant Posterior Hip Dislocation, Ipsilateral Intertrochanteric- and Proximal Tibial- Fractures with Popliteal Artery Injury: A Challenging Trauma Mélange

    PubMed Central

    Chotai, Pranit N.; Hart, Ryan; Wassef, Andrew

    2015-01-01

    Constellation of ipsilateral posterior hip dislocation, intertrochanteric- and proximal tibial fracture with popliteal artery injury is rare. Management of this presentation is challenging. A motor vehicle accident victim presented with these injuries, but without any initial signs of vascular compromise. Popliteal artery injury was diagnosed intra-operatively and repaired. This was followed by external fixation of tibial fracture, open reduction of dislocated hip and internal fixation of intertrochanteric fracture. Patient regained bilateral complete weight bearing and returned to pre-accident activity level. Apt surgical management including early repair of vascular injury in such a trauma mélange allows for a positive postoperative outcome. PMID:26918095

  16. Ipsilateral Traumatic Posterior Hip Dislocation, Posterior Wall and Transverse Acetabular Fracture with Trochanteric Fracture in an adult: Report of First Case

    PubMed Central

    Sinha, Skand; Naik, Ananta k; Arya, Rajendra K; Jain, Vijay K

    2013-01-01

    Introduction: Posterior dislocation of the hip joint with associated acetabular and intertrochanteric fracture is a complex injury. Early recognition, prompt and stable reduction is needed of successful outcome. Case Report: 45 year old male patient presented with posterior dislocation of the hip with transverse fracture with posterior wall fracture of acetabulam and intertrochanteric fracture on the ipsilateral side. The complex fracture geometry was confirmed by CT scan. The patient was successfully managed by open reduction and internal fixation of intertrochanteric fracture was achieved with dynamic hip screw (DHS) plate fixation followed by fixation of acetabular fracture with reconstruction plate. Conclusion: Hip dislocation combined with acetabular fracture is an uncommon injury; this article presents a unique case of posterior wall and transverse fractures of ipsilateral acetabulum with intertrochanteric fracture in a patient who sustained traumatic posterior hip dislocation. Early surgical intervention is important for satisfactory outcomes of such complex fracture-dislocation injuries. PMID:27298928

  17. Developmental dysplasia of the hip

    MedlinePlus

    ... Developmental hip dysplasia; DDH; Congenital dysplasia of the hip; Congenital dislocation of the hip; CDH; Pavlik harness ... dislocation Shorter leg on the side with the hip dislocation Uneven skin folds of thigh or buttocks After ...

  18. Effect of femoral head size on risk of revision for dislocation after total hip arthroplasty

    PubMed Central

    Kostensalo, Inari; Junnila, Mika; Virolainen, Petri; Remes, Ville; Matilainen, Markus; Vahlberg, Tero; Pulkkinen, Pekka; Eskelinen, Antti; Mäkelä, Keijo T

    2013-01-01

    Background and purpose Previous population-based registry studies have shown that larger femoral head size is associated with reduced risk of revision for dislocation. However, the previous data have not included large numbers of hip resurfacing arthroplasties or large metal-on-metal (> 36-mm) femoral head arthroplasties. We evaluated the association between femoral component head size and the risk of revision for dislocation after THA by using Finnish Arthroplasty Register data. Patients and methods 42,379 patients who were operated during 1996–2010 fulfilled our criteria. 18 different cup/stem combinations were included. The head-size groups studied (numbers of cases) were 28 mm (23,800), 32 mm (4,815), 36 mm (3,320), and > 36 mm (10,444). Other risk factors studied were sex, age group (18–49 years, 50–59 years, 60–69 years, 70–79 years, and > 80 years), and time period of operation (1996–2000, 2001–2005, 2006–2010). Results The adjusted risk ratio in the Cox model for a revision operation due to dislocation was 0.40 (95% CI: 0.26–0.62) for 32-mm head size, 0.41 (0.24–0.70) for 36-mm head size, and 0.09 (0.05–0.17) for > 36-mm head size compared to implants with a head size of 28 mm. Interpretation Larger femoral heads clearly reduce the risk of dislocation. The difference in using heads of > 36 mm as opposed to 28-mm heads for the overall revision rate at 10 years follow-up is about 2%. Thus, although attractive from a mechanical point of view, based on recent less favorable clinical outcome data on these large heads, consisting mainly of metal-on-metal prostheses, one should be cautious using these implants. PMID:23799348

  19. Open anterior dislocation of the hip in an adult: a case report and review of literature☆☆☆

    PubMed Central

    de Oliveira, Anderson Luiz; Machado, Eduardo Gomes

    2014-01-01

    Open anterior hip dislocation is a rare condition and results from high‐energy trauma. Ten cases of open anterior dislocation have been described in the literature so far. Its rarity is due to the inherent stability of the joint, its deep position in the pelvis, with strong ligaments and bulky muscles around the articulation. Several factors influence the prognosis, such as the degree of compounding, the associated soft tissue injuries, the age of the patient and, mainly, the delay in reduction. The main complications are: arthrosis of the hip, with incidence of 50% of cases, when associated with fractures of the femoral head; and osteonecrosis of the femoral head, with incidence between 1.7 and 40% (in closed anterior dislocation). Because of the rarity and the potential disability of this lesion, we report a case in a 46‐year‐old man, involved in an automobile accident. The hip was reduced (anterior superior dislocation) in the first three hours of the trauma. The patient was kept non‐weight bearing until sixth week, with complete weight bearing after 10th week. After one year follow‐up, the functional result was poor (Harris Hip Score: 52), probably because of the associated labral tear, but without signs of osteonecrosis of the femoral head in magnetic resonance imaging. PMID:26229781

  20. Femoral Varus Osteotomy for Hip Instability after Traumatic Fracture Dislocations of the Hip Associated with Femoral Head Fractures: A Report of Two Cases

    PubMed Central

    Nakamura, Junichi; Takahashi, Kazuhisa

    2016-01-01

    Fracture of the femoral head and the acetabulum with traumatic dislocation of the hip is a severe injury representing various types and unfavorable outcome. We showed a 45-year-old man with Pipkin type-IV fracture and coxa valga. An immediate closed reduction was achieved followed by open reduction and internal fixation via a posterior approach 6 days later. However, dislocation occurred three times without traumatic events after three weeks. CT demonstrated no displacement of posterior fragments or implant failure. Femoral intertrochanteric varus osteotomy was performed to gain concentric stability and successfully resolved recurrent dislocation. Another 45-year-old woman with Pipkin type-IV fracture and coxa valga also underwent closed reduction initially and then continued conservative treatment. After eight weeks, when she started gait training, progressive pain became symptomatic. Persistent hip pain at weight bearing was not improved in spite of arthroscopic synovectomy and osteochondroplasty. Two years after injury, femoral intertrochanteric varus osteotomy was indicated and her refractory pain was resolved gradually. We suggest that femoral varus osteotomy should be considered for superolateral subluxation associated fracture dislocation of the hip in Pipkin type-IV and coxa valga. PMID:27293934

  1. Femoral Varus Osteotomy for Hip Instability after Traumatic Fracture Dislocations of the Hip Associated with Femoral Head Fractures: A Report of Two Cases.

    PubMed

    Miyamoto, Shuichi; Nakamura, Junichi; Iida, Satoshi; Suzuki, Chiho; Ohtori, Seiji; Orita, Sumihisa; Takahashi, Kazuhisa

    2016-01-01

    Fracture of the femoral head and the acetabulum with traumatic dislocation of the hip is a severe injury representing various types and unfavorable outcome. We showed a 45-year-old man with Pipkin type-IV fracture and coxa valga. An immediate closed reduction was achieved followed by open reduction and internal fixation via a posterior approach 6 days later. However, dislocation occurred three times without traumatic events after three weeks. CT demonstrated no displacement of posterior fragments or implant failure. Femoral intertrochanteric varus osteotomy was performed to gain concentric stability and successfully resolved recurrent dislocation. Another 45-year-old woman with Pipkin type-IV fracture and coxa valga also underwent closed reduction initially and then continued conservative treatment. After eight weeks, when she started gait training, progressive pain became symptomatic. Persistent hip pain at weight bearing was not improved in spite of arthroscopic synovectomy and osteochondroplasty. Two years after injury, femoral intertrochanteric varus osteotomy was indicated and her refractory pain was resolved gradually. We suggest that femoral varus osteotomy should be considered for superolateral subluxation associated fracture dislocation of the hip in Pipkin type-IV and coxa valga. PMID:27293934

  2. [Traumatic hip dislocation in children. Case report of a 4 year-old girl].

    PubMed

    Martínez-Guerrero, J I; Olguín-Hernández, F; Cabrera, A

    2012-01-01

    Traumatic hip dislocation with a history of high energy trauma is infrequent in children. The incidence rate in our country has not been determined in the literature. Everything depends on the patient's age group, the type of trauma and the ligament laxity of children. We report herein the case of a 4 year-old girl with this condition and a history of high energy trauma. She was seen at Aragón Pediatric Hospital, SSDF, 8 hours after the injury and received conservative treatment. She has done well so far and has been followed-up monthly for 18 months, without complications. Avascular necrosis of the femoral head is the most frequent complication and has irreversible sequelae. After the follow-up period the patient is totally functional and independent. PMID:23320340

  3. High-grade SCFE: the role of surgical hip dislocation and reduction.

    PubMed

    Sucato, Daniel J; De La Rocha, Adriana

    2014-01-01

    The patient with an unstable slipped capital femoral epiphysis poses a challenging problem to the treating physician to improve the position of the displaced epiphysis to avoid femoroacetabular impingement without developing avascular necrosis (AVN)-a potentially devastating complication. Although the standard operative procedure of in situ pinning following an incidental reduction while positioning the patient on the table, has been the mainstay of treatment in North America, other viable options are available including a surgical dislocation approach to the hip followed by a modified Dunn osteotomy with control of the retinacular vessels, reduction of the epiphysis, and internal fixation with pins or screws. Although technically demanding, this approach offers an opportunity to reduce the epiphysis to avoid femoroacetabular impingement, and limit the possibility for the development of AVN. The early results for this procedure are promising with all studies demonstrating excellent reduction of the epiphysis and an overall lower incidence of AVN when compared with in situ pinning. PMID:25207732

  4. A Novel Approach for Dynamic Testing of Total Hip Dislocation under Physiological Conditions

    PubMed Central

    Herrmann, Sven; Kluess, Daniel; Kaehler, Michael; Grawe, Robert; Rachholz, Roman; Souffrant, Robert; Zierath, János; Bader, Rainer; Woernle, Christoph

    2015-01-01

    Constant high rates of dislocation-related complications of total hip replacements (THRs) show that contributing factors like implant position and design, soft tissue condition and dynamics of physiological motions have not yet been fully understood. As in vivo measurements of excessive motions are not possible due to ethical objections, a comprehensive approach is proposed which is capable of testing THR stability under dynamic, reproducible and physiological conditions. The approach is based on a hardware-in-the-loop (HiL) simulation where a robotic physical setup interacts with a computational musculoskeletal model based on inverse dynamics. A major objective of this work was the validation of the HiL test system against in vivo data derived from patients with instrumented THRs. Moreover, the impact of certain test conditions, such as joint lubrication, implant position, load level in terms of body mass and removal of muscle structures, was evaluated within several HiL simulations. The outcomes for a normal sitting down and standing up maneuver revealed good agreement in trend and magnitude compared with in vivo measured hip joint forces. For a deep maneuver with femoral adduction, lubrication was shown to cause less friction torques than under dry conditions. Similarly, it could be demonstrated that less cup anteversion and inclination lead to earlier impingement in flexion motion including pelvic tilt for selected combinations of cup and stem positions. Reducing body mass did not influence impingement-free range of motion and dislocation behavior; however, higher resisting torques were observed under higher loads. Muscle removal emulating a posterior surgical approach indicated alterations in THR loading and the instability process in contrast to a reference case with intact musculature. Based on the presented data, it can be concluded that the HiL test system is able to reproduce comparable joint dynamics as present in THR patients. PMID:26717236

  5. A Novel Approach for Dynamic Testing of Total Hip Dislocation under Physiological Conditions.

    PubMed

    Herrmann, Sven; Kluess, Daniel; Kaehler, Michael; Grawe, Robert; Rachholz, Roman; Souffrant, Robert; Zierath, János; Bader, Rainer; Woernle, Christoph

    2015-01-01

    Constant high rates of dislocation-related complications of total hip replacements (THRs) show that contributing factors like implant position and design, soft tissue condition and dynamics of physiological motions have not yet been fully understood. As in vivo measurements of excessive motions are not possible due to ethical objections, a comprehensive approach is proposed which is capable of testing THR stability under dynamic, reproducible and physiological conditions. The approach is based on a hardware-in-the-loop (HiL) simulation where a robotic physical setup interacts with a computational musculoskeletal model based on inverse dynamics. A major objective of this work was the validation of the HiL test system against in vivo data derived from patients with instrumented THRs. Moreover, the impact of certain test conditions, such as joint lubrication, implant position, load level in terms of body mass and removal of muscle structures, was evaluated within several HiL simulations. The outcomes for a normal sitting down and standing up maneuver revealed good agreement in trend and magnitude compared with in vivo measured hip joint forces. For a deep maneuver with femoral adduction, lubrication was shown to cause less friction torques than under dry conditions. Similarly, it could be demonstrated that less cup anteversion and inclination lead to earlier impingement in flexion motion including pelvic tilt for selected combinations of cup and stem positions. Reducing body mass did not influence impingement-free range of motion and dislocation behavior; however, higher resisting torques were observed under higher loads. Muscle removal emulating a posterior surgical approach indicated alterations in THR loading and the instability process in contrast to a reference case with intact musculature. Based on the presented data, it can be concluded that the HiL test system is able to reproduce comparable joint dynamics as present in THR patients. PMID:26717236

  6. Leg lengthening of more than 5 cm is a risk factor for sciatic nerve injury after total hip arthroplasty for adult hip dislocation

    PubMed Central

    Higuchi, Yoshitoshi; Hasegawa, Yukiharu; Ishiguro, Naoki

    2015-01-01

    ABSTRACT Total hip arthroplasty (THA) in patients with high hip dislocation is challenging and technically demanding. Nerve injury is a problem associated with leg lengthening after THA. The purpose of this study was to identify the risk factors for sciatic nerve injury after THA in patients with high hip dislocation. Thirty-seven patients (41 THAs) with Crowe type IV hips were consecutively treated. The average leg lengthening (LL) was 3.2 cm. The average Harris hip score was improved from 57.5 points to 83.1 points at the final follow-up. The clinical outcomes after an average 6.4-years follow-up were satisfactory. Sciatic nerve injury was observed in two joints. LL in the two joints (two patients) with sciatic nerve injury was 5.2 cm and 6.7 cm, respectively. Leg lengthening of >5 cm was a risk factor for sciatic nerve injury. Therefore, leg lengthening of >5 cm should be avoided to prevent sciatic nerve injury. PMID:26412892

  7. Relationship between developmental dislocation of the hip in infant and acetabular dysplasia at skeletal maturity.

    PubMed

    Okano, Kunihiko; Yamaguchi, Kazumasa; Ninomiya, Yoshikazu; Matsubayashi, Shohei; Aoyagi, Kiyoshi; Osaki, Makoto; Enomoto, Hiroshi; Takahashi, Katsuro

    2015-01-01

    Previous reports demonstrated 8-60% patients treated for developmental dislocation of hip (DDH) in infancy have residual acetabular dysplasia (AD) at skeletal maturity. AD patients reportedly exhibit abnormal morphology of the pelvis, high rates of comorbid spinal congenital anomalies and high bone mineral density. These physical findings suggest that AD patients have genetic background. We examined the percentage of AD patients with hip pain at skeletal maturity having a history of DDH in infancy and the correlation between the severity of AD at skeletal maturity and history of DDH treatment to investigate the relationship between AD and DDH.A total of 245 patients were radiographically examined for any history of DDH treatment in infancy. The study included 226 women and 19 men with a mean age at examination of 40.7 years (range 17-59 years).Eighty-eight patients (36%) had a history of DDH treatment (DDH group) and the remaining 157 patients (64%) had no history of DDH treatment (non-DDH group). The average age was lower and acetabular angle was larger in the DDH group. There was a significant increasing trend of the percentage of DDH patients associated with the severity of AD classified with CE, acetabular angle, and acetabular roof angle.Our data suggest that there are several AD patients without a history of DDH in Japan, and AD in patients without a history of DDH has different characteristics from AD in patients with a history of DDH. PMID:25569642

  8. Prevention of dislocation of the hip in children with cerebral palsy: 20-year results of a population-based prevention programme.

    PubMed

    Hägglund, G; Alriksson-Schmidt, A; Lauge-Pedersen, H; Rodby-Bousquet, E; Wagner, P; Westbom, L

    2014-11-01

    In 1994 a cerebral palsy (CP) register and healthcare programme was established in southern Sweden with the primary aim of preventing dislocation of the hip in these children. The results from the first ten years were published in 2005 and showed a decrease in the incidence of dislocation of the hip, from 8% in a historical control group of 103 children born between 1990 and 1991 to 0.5% in a group of 258 children born between 1992 and 1997. These two cohorts have now been re-evaluated and an additional group of 431 children born between 1998 and 2007 has been added. By 1 January 2014, nine children in the control group, two in the first study group and none in the second study group had developed a dislocated hip (p < 0.001). The two children in the first study group who developed a dislocated hip were too unwell to undergo preventive surgery. Every child with a dislocated hip reported severe pain, at least periodically, and four underwent salvage surgery. Of the 689 children in the study groups, 91 (13%) underwent preventive surgery. A population-based hip surveillance programme enables the early identification and preventive treatment, which can result in a significantly lower incidence of dislocation of the hip in children with CP. PMID:25371472

  9. Dysplasia of the contralateral hip in patients with unilateral late-detected congenital dislocation of the hip: 50 years' follow-up of 48 patients.

    PubMed

    Terjesen, T

    2014-09-01

    The aim of this study was to investigate the incidence of dysplasia in the 'normal' contralateral hip in patients with unilateral developmental dislocation of the hip (DDH) and to evaluate the long-term prognosis of such hips. A total of 48 patients (40 girls and eight boys) were treated for late-detected unilateral DDH between 1958 and 1962. After preliminary skin traction, closed reduction was achieved at a mean age of 17.8 months (4 to 65) in all except one patient who needed open reduction. In 25 patients early derotation femoral osteotomy of the contralateral hip had been undertaken within three years of reduction, and later surgery in ten patients. Radiographs taken during childhood and adulthood were reviewed. The mean age of the patients was 50.9 years (43 to 55) at the time of the latest radiological review. In all, eight patients (17%) developed dysplasia of the contralateral hip, defined as a centre-edge (CE) angle < 20° during childhood or at skeletal maturity. Six of these patients underwent surgery to improve cover of the femoral head; the dysplasia improved in two after varus femoral osteotomy and in two after an acetabular shelf operation. During long-term follow-up the dysplasia deteriorated to subluxation in two patients (CE angles 4° and 5°, respectively) who both developed osteoarthritis (OA), and one of these underwent total hip replacement at the age of 49 years. In conclusion, the long-term prognosis for the contralateral hip was relatively good, as OA occurred in only two hips (4%) at a mean follow-up of 50 years. Regular review of the 'normal' side is indicated, and corrective surgery should be undertaken in those who develop subluxation. PMID:25183584

  10. A modified method of traction for young children with congenital dislocation of the hip as a preliminary to reduction.

    PubMed

    Pan, K L; Rasit, H

    2004-12-01

    Many authors agree that preliminary traction prior to closed or open reduction for congenital dislocation of the hip is helpful. Different ways of traction have been used and each of them has its own advantages and disadvantages. One of the problems in the very young child is the difficulty in maintaining a suitable traction that is biomechanically effective. We found that using a rocker bed made the traction more "user friendly" for the child, the parent and the doctors. PMID:15941161

  11. Dislocation

    MedlinePlus

    ... likely to happen again. Follow-up with an orthopedic surgeon is recommended after a dislocation. ... SE, Mehta A, Maddow C, Luber SD. Critical orthopedic skills and procedures. Emergency Medicine Clinics of North ...

  12. Dislocations

    MedlinePlus

    ... Attempting to move or jam a dislocated bone back in can damage blood vessels, muscles, ligaments, and nerves. Apply an ice pack. Ice can ease swelling and pain in and around the joint. Use ibuprofen or acetaminophen for pain. Think Prevention! Make sure kids wear the appropriate safety gear ...

  13. Clinical results of cementless total hip arthroplasty with shortening osteotomy for high dislocation with developmental dysplasia.

    PubMed

    Desteli, Engin Eren; Imren, Yunus; Tan, Erkan; Erdoğan, Murat; Özcan, Hüseyin

    2015-03-01

    Total hip arthroplasty for severe developmental dysplasia of the hip is a technically challenging procedure. Subtrochanteric femoral osteotomy enables reducing the femoral head and restoring abductor muscle strength without compromising proximal femoral bone stock in advanced dysplasia.We aimed to retrospectively evaluate Crowe type III or IV developmental dysplasia of the hip who underwent reconstruction with cementless total hip arthroplasty combined with a transverse subtrochanteric femoral osteotomy. Sixty hips of 52 patients (11 male, 49 female) with Crowe type III (n: 37) or IV (n: 23) developmental dysplasia of the hip were included. The average age was 51.4 years. Surgery was performed in lateral decubitis position with posterolateral approach. Subtrochanteric transverse femoral osteotomy were used with cementless components. 40 of the femoral components were Secur-Fit type, and 20 of them were secur-fit plus max type. Ceramic-ceramic coupling was used in 24 cases and metal-polyethylene coupling was used in 36 cases. Merle D'Aubigne and Harris Hip score were used to rate the clinical outcome at the final follow up. All femoral shortening osteotomies were united at a mean of 5.7 months. Mean Merle D'Aubigne pain score was increased from 3.1 to 5.4, and mean Harris Hip score improved from 39 to 92.8, postoperatively (p<0.01). There was no significant difference in time to union between different types of stems. 4 femoral stems had asymptomatic radiolucent lines. There was no significant difference in time to union between different types of stems. PMID:26280851

  14. Hip Dislocation Increases Roughness of Oxidized Zirconium Femoral Heads in Total Hip Arthroplasty: An Analysis of 59 Retrievals

    PubMed Central

    Moussa, Mohamed E.; Esposito, Christina I.; Elpers, Marcella E.; Wright, Timothy M.; Padgett, Douglas E.

    2014-01-01

    The aims of this study were to assess damage on the surface of retrieved oxidized zirconium metal (OxZr) femoral heads, to measure surface roughness of scratches, and to evaluate the extent of surface effacement using scanning electron microscopy (SEM). Ceramic zirconia-toughened alumina (ZTA) heads were analyzed for comparison. OxZr femoral heads explanted for recurrent dislocation had the most severe damage (p<0.001). The median surface roughness of damaged OxZr femoral heads was 1.49μm, compared to 0.084μm for damaged ZTA heads and 0.052μm for undamaged OxZr (p<0.001). This may be of clinical concern because increased surface roughness has the potential to increase the wear of polyethylene liners articulating against these OxZr heads in THA. PMID:25443362

  15. Patterns of postural deformity in non-ambulant people with cerebral palsy: what is the relationship between the direction of scoliosis, direction of pelvic obliquity, direction of windswept hip deformity and side of hip dislocation?

    PubMed Central

    Michael, Shona; Kirkwood, Craig

    2008-01-01

    Objective: To investigate: (a) associations between the direction of scoliosis, direction of pelvic obliquity, direction of windswept deformity and side of hip subluxation/dislocation in non-ambulant people with cerebral palsy; and (b) the lateral distribution of these postural asymmetries. Design: Cross-sectional observational study. Setting: Posture management services in three centres in the UK. Subjects: Non-ambulant people at level five on the gross motor function classification system for cerebral palsy. Main measures: Direction of pelvic obliquity and lateral spinal curvature determined from physical examination, direction of windswept hip deformity derived from range of hip abduction/adduction, and presence/side of unilateral hip subluxation defined by hip migration percentage. Results: A total of 747 participants were included in the study, aged 6–80 years (median 18 years 10 months). Associations between the direction of scoliosis and direction of pelvic obliquity, and between the direction of windswept hip deformity and side hip subluxation/dislocation were confirmed. A significant association was also seen between the direction of scoliosis and the direction of the windswept hip deformity (P < 0.001) such that the convexity of the lateral spinal curve was more likely to be opposite to the direction of windsweeping. Furthermore, significantly more windswept deformities to the right (P = 0.007), hips subluxed on the left (P = 0.002) and lateral lumbar/lower thoracic spinal curves convex to the left (P = 0.03) were observed. Conclusions: The individual asymmetrical postural deformities are not unrelated in terms of direction and not equally distributed to the left/right. A pattern of postural deformity was observed. PMID:18042604

  16. Imaging in the Surgical Management of Developmental Dislocation of the Hip

    PubMed Central

    Harcke, H. T.; Thacker, Mihir

    2008-01-01

    Although the use of ultrasound in the diagnosis and early treatment of developmental dysplasia of the hip (DDH) has reduced the number of patients diagnosed late and decreased the number of operative procedures, surgical treatment is still needed in some patients. Late cases continue to occur as a result of missing the screening examination, being normal at initial screening and missing followup. Dysplasia may persist despite appropriate nonoperative or operative treatment. Many of these patients subsequently undergo closed or open reduction and femoral or acetabular reconstruction. Ultrasound of the hips is generally used up to 6 or 8 months of age, during which time the hips are largely cartilaginous, and radiographs after that time when bony development is more complete. Options to supplement ultrasound and radiography include arthrography, computed tomography, and magnetic resonance imaging. Several advances have been made in the imaging of DDH and its complications including acetabular labral pathology and of femoroacetabular impingement (FAI). We review imaging techniques other than ultrasound used in the management of DDH. Level of Evidence: Level V, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18288547

  17. TREATMENT OF PARALYTIC HIP DISLOCATION AMONG SPASTIC QUADRIPLEGIC CEREBRAL PALSY PATIENTS BY MEANS OF FEMORAL AND PELVIC OSTEOTOMY, WITHOUT OPENING THE JOINT CAPSULE (CAPSULOPLASTY)

    PubMed Central

    Junior, Fernando Farcetta; Abreu, Fabio Peluzo; Neves, Daniella Lins; Kertzman, Paulo Facciola; Zuccon, Alexandre; De Oliveira Bittencourt, Simone; Lopes, Davi Moshe Leopold

    2015-01-01

    Objectives: To show the preoperative planning and results from surgical treatment for paralytic hip dislocation among patients with cerebral palsy. The techniques used were proximal femoral varus derotation osteotomy in association with Dega iliac osteotomy, without opening the joint capsule. Methods: We performed a retrospective review of ten hips in eight patients with spastic quadriplegic cerebral palsy who underwent surgical treatment between 2003 and 2005, with the same surgical technique. The pre and postoperative clinical and radiological parameters, and the preoperative planning using an image intensifier, were assessed. The clinical parameters analyzed were: pain, hygiene-related difficulties and positioning difficulties. The radiological parameters were Reimer's index, the acetabular index and the neck-shaft angle. These results were subjected to statistical analysis. Results: We obtained good results with this technique. After a mean follow-up of three years, all the hips were observed to be stable at the last assessment, and there was a high degree of satisfaction among the families in relation to the treatment. We also showed that preoperative planning using an image intensifier allowed us to reduce and stabilize these hips without the need for capsuloplasty. Conclusion: The authors conclude that in treating hip dislocation among spastic quadriplegic cerebral palsy patients, capsuloplasty is unnecessary for stabilizing the coxofemoral joint. PMID:27022539

  18. Effects of arthroscopic-assisted surgery on irreducible developmental dislocation of hip by mid-term follow-up: An observational study.

    PubMed

    Xu, Hui-Fa; Yan, Ya-Bo; Xu, Chao; Li, Tian-Qing; Zhao, Tian-Feng; Liu, Ning; Huang, Lu-Yu; Zhang, Chun-Li; Lei, Wei

    2016-08-01

    The purpose of this study was to investigate the indications, surgical technique, and the clinical effects of arthroscopic-assisted treatment of irreducible developmental dislocation of the hip by mid-term follow-up. Arthroscopic-assisted surgeries were performed on 40 children (52 hips) between January 2005 and December 2009. Anterior and antero-superior greater trochanter portals were used in these treatments. Spica cast and abduction splint were applied for 3 months postoperatively. The follow-up was conducted on every 3 months postoperatively. During 12-month follow-up, a secondary treatment such as acetabuloplasty and/or femoral osteotomy (shortening, varus, and derotation) was applied if the acetabular angle was greater than 25°. The pelvic acetabular angle, Mckay and Severin score were evaluated every 6 months in all children. With 36 to 96 months (average 71 months) follow-up, 35 children (44 hips) were successfully followed up with complete case data while 5 children unsuccessfully. According to Tönnis classification, there were 5 grade 1 hips, 14 grade 2 hips, 14 grade 3 hips, 11 grade 4 hips, in which 3 children (4 hips) were failed in arthroscopic reduction and femoral head avascular necrosis occurred in 2 children (4 hips). According to Mckay standard, the good rate is 100%. According to Severin standard, the good rate is 84.1%. Arthroscopic assisted treatment is an effective way of reduction of the irreducible hip. Compared with the open reduction, arthroscopic treatment combined with acetabuloplasty and/or femoral osteotomy has advantages of less trauma and better function preservation. PMID:27537595

  19. Osteonecrosis of the Femoral Head in the Setting of a Complex Acetabulum Fracture without Hip Dislocation Treated Surgically Using Ilio-inguinal Approach: A Case Report

    PubMed Central

    Sobti, Anshul Shyam

    2014-01-01

    Osteonecrosis in isolated fractures of the acetabulum without dislocation of hip seems to be a known complication, but to our knowledge it has not been reported adequately. The causative nature of post-traumatic femoral head osteonecrosis has not been studied critically. The pathophysiology of osteonecrosis in this case also eludes us. Striking evidence points towards the intra-operative blood loss and low mean arterial pressure possibly leading to hypo-perfusion of femoral head leading to osteonecrosis. Fractures of the acetabulum pose a difficult problem for the patient and the surgeon because of possible complications. Thus any surgeon involved in surgery for fractures of the acetabulum should be aware of the possibility of this potential complication. Here is a 61-year male, who sustained a complex fracture of the acetabulum without hip dislocation, subsequently was treated surgically with internal fixation using an anterior approach, 10 months after surgery patient developed osteonecrosis of the femoral head.

  20. [An abduction applicance for congenital dislocation of the hip (author's transl)].

    PubMed

    Lang, G; Kehr, P; Paternotte, H; Aebi, J; Pintu, J

    1980-06-21

    The appliance described consists of a shoulder belt from which an abduction bar is hanging. Two adjustable rings enclosing the thigh and the leg of the child are attached to the shoulder-belt and to the bar. The lower limb is not immobilized but kept flexes and abducted. The appliance is primarliy used for those children with minor dysplasis of the hip who do not require complete immobilization but cannot be left without any treatment. It is also useful after prolonged orthopaedic or surgical immobilization. PMID:7402893

  1. Plastic deformation and impaction of the retroacetabular surface associated with posterior fracture-dislocation of the hip: description of two cases.

    PubMed

    Meier, Sandra; Isler, Balz; Gautier, Emanuel

    2007-10-01

    In two cases of posterior fracture-dislocation of the hip, we found an impaction and plastic deformation of the retroacetabular surface, in addition to other typically associated lesions. This deformation creates a mismatch between the stable and the free fragments of the posterior wall, and if unrecognized makes an anatomic reconstruction of the posterior wall impossible. On the computed tomography scan, the most characteristic sign is a concave deformation of the retroacetabular region as compared to the contralateral side. To our knowledge, this specific fracture-dislocation pattern has not been previously described in the literature. If orthopedic surgeons know about the existence of this deformation, then they will easily recognize the impaction on preoperative computed tomography scan and will be able to achieve an anatomic reduction of the acetabulum. Diagnostic aspects and the operative technique to approach this problem are described and illustrated in two cases. PMID:17921844

  2. Bilateral Staged Total Hip Replacement and the Natural Progress of an Untreated Case of Developmental Dysplasia (Dislocation) of the Hip: A Clinical Case Report by the Surgeon and the Patient

    PubMed Central

    Honarpisheh, Hamid; Ghazavi, Mohammad Taghi

    2015-01-01

    The natural history of an untreated case of a Developmental Dysplasia (Dislocation) of the Hip (DDH) associated with multiple congenital abnormalities is reported in a 55-years-old man. The patient’s complaints and the varieties of the typical manifestations emerged in other parts of the body throughout the life are reviewed and discussed as comorbidities of a dysplastic condition. Two-stage bilateral total hip replacement (THR) operations were performed at the age of 55. In addition, to relieve the pain, the walking disabilities were overcome, hence gaining normal walking in swing and stances. The leg length discrepancy was corrected by anatomically positioned prostheses, examined by the knee bending test and characterized and evidenced by radiological features and indices. PMID:26170527

  3. Bilateral Staged Total Hip Replacement and the Natural Progress of an Untreated Case of Developmental Dysplasia (Dislocation) of the Hip: A Clinical Case Report by the Surgeon and the Patient.

    PubMed

    Honarpisheh, Hamid; Ghazavi, Mohammad Taghi

    2015-07-01

    The natural history of an untreated case of a Developmental Dysplasia (Dislocation) of the Hip (DDH) associated with multiple congenital abnormalities is reported in a 55-years-old man. The patient's complaints and the varieties of the typical manifestations emerged in other parts of the body throughout the life are reviewed and discussed as comorbidities of a dysplastic condition. Two-stage bilateral total hip replacement (THR) operations were performed at the age of 55. In addition, to relieve the pain, the walking disabilities were overcome, hence gaining normal walking in swing and stances. The leg length discrepancy was corrected by anatomically positioned prostheses, examined by the knee bending test and characterized and evidenced by radiological features and indices. PMID:26170527

  4. Hip Injuries and Disorders

    MedlinePlus

    ... or falling can all sometimes lead to hip injuries. These include Strains Bursitis Dislocations Fractures Certain diseases also lead to hip injuries or problems. Osteoarthritis can cause pain and limited ...

  5. Right upper limb bud triplication and polythelia, left sided hemihypertrophy and congenital hip dislocation, facial dysmorphism, congenital heart disease, and scoliosis: disorganisation-like spectrum or patterning gene defect?

    PubMed Central

    Sabry, M A; al-Saleh, Q; al-Saw'an, R; al-Awadi, S A; Farag, T I

    1995-01-01

    A Somali female baby with right upper limb triplication, polythelia, left sided hemihypertrophy, congenital hip dislocation, facial dysmorphism, congenital heart disease, and scoliosis is described. It seems that the above described pattern of anomalies has not been reported before. The possible developmental genetic mechanism responsible for this phenotype is briefly discussed. Images PMID:7562971

  6. [Spasm of the adductor muscles, pre-dislocations and dislocations of the hip joints in children and adolescents with cerebral palsy. Clinical observations on aetiology, pathogenesis, therapy and rehabilitation. Part II. The importance of the iliopsoas tendon, its tenotomy, of the coxa valga antetorta, and correction through osteotomy turning the hip into varus (author's transl)].

    PubMed

    Fettweis, E

    1979-02-01

    The following factors besides spasm and contraction of the adductor muscles contribute to the occurrence of dislocations of the hip in spastic paralysis: Spasm and contraction of the iliopsoas muscle and enhanced valgus position and antetorsion. The author holds the opinion that in case of malformation of the proximal end of the femur, it is not only the indirect action of the spastic musculature via the proximal femur-epiphyseal cartilage which is responsible for this phenomen in accordance with the law on functional adaption through longitudinal growth (Pauwels), but also the direct traction of the iliopsoas tendon. A clue in this direction is the often very pronounced elongation or enlargement of the trochanter minor. The author demonstrates the pathogenetic importance of iliopsoas contracture and malpositioning of the neck of the femur by means of analyses of the course in two patients. The following principles of treatment are postulated for spastic dislocation of the hip: Elimination of the pathogenetic factors through myotenotomy of the adductor muscles and complete resection of the obturator nerve, with observation of strict aftertreatment criteria, tenotomy of the iliopsoas, repositioning and osteotomy with turning into varus. Osteotomy without previous elimination of the pathogenetically acting muscular forces does not appear useful. Likewise, permanent re-positioning by means of muscle-relaxing operation cannot be sufficiently safe-guarded without additional osteotomy once the dislocation has taken place. In twelve patients with spastic dislocation of the hip, treated in accordance with these guidelines (two without osteotomy) aged 6 6/12 and 19 5/12 years, a roentgenologically good result was obtained in half of the cases, whereas the functional result was satisfactory not only with these patients but also with part of the other patients. If surgical treatment is instituted early enough, and if the experiences described here are taken into consideration

  7. [Sonographic measures of the hip joint of 1328 newborns of Han and Uygur nationalities-relative factors of congenital dislocation of hip].

    PubMed

    Yang, J; Chen, L; Tian, B

    1997-08-01

    The four sonographic methods (Engesaeter, Terjesen, Graf, Morin-Harcke) were used for examining the hip joint of 1328 newborns of Han and Uygur nationalities. The difference between Han and Uygur newborns was not statistical significant, but some literatures reported that in our country, the incidence of different nationalities in different regions varied. Our conclusion is that there is no obvious relationship between the depth of the acetabulum and the percentage of the femoral head covered by the acetabulum. It is caused by other factors, inherent or acquired. The value of the hip joint of the male and female has significant difference (P < 0.0005). The incidence of CDH in girls is much higher than that in boys. This may be related to the different depth of the acetabulum and different percentage of the femoral head covered by the acetabulum. In the period of newborn, girl's depth of the acetabulum is smaller than that of boys. PMID:10678065

  8. The Effect of Dislocation Type (Crowe Types I-IV) on Pelvic Development in Developmental Dysplasia of the Hip: A Radiologic Study of Anatomy.

    PubMed

    Bilgen, Ömer Faruk; Salar, Necmettin; Bilgen, Muhammet Sadık; Mutlu, Müren; Kara, Gökhan Kürşat; Gürsel, Enis

    2015-05-01

    Classification of hip pathology in developmental dysplasia of the hip (DDH) helps in appropriate placement of implants during total hip arthroplasty. We examined preoperative unilateral and bilateral pelvic radiographs of 57 patients (114 hips) undergoing total hip arthroplasty because of DDH. Both sides of the pelvis were visually separated into 3 areas for comparison. When area ratios of hips with Crowe types II, III, and IV DDH were compared with ratios for healthy hips, values in hips with DDH were significantly low for the iliac wings, significantly high for the acetabular regions, and significantly low for the ischial area. Using a line crossing the healthy hip's teardrop and parallel to a line joining the distal sacroiliac joints is useful for calculating limb-length discrepancy. PMID:25499171

  9. Total hip replacement through a posterior approach using a 22 mm diameter femoral head : the role of the transverse acetabular ligament and capsular repair in reducing the rate of dislocation.

    PubMed

    Kumar, V; Sharma, S; James, J; Hodgkinson, J P; Hemmady, M V

    2014-09-01

    Despite a lack of long-term follow-up, there is an increasing trend towards using femoral heads of large diameter in total hip replacement (THR), partly because of the perceived advantage of lower rates of dislocation. However, increasing the size of the femoral head is not the only way to reduce the rate of dislocation; optimal alignment of the components and repair of the posterior capsule could achieve a similar effect. In this prospective study of 512 cemented unilateral THRs (Male:Female 230:282) performed between 2004 and 2011, we aimed to determine the rate of dislocation in patients who received a 22 mm head on a 9/10 Morse taper through a posterior approach with capsular repair and using the transverse acetabular ligament (TAL) as a guide for the alignment of the acetabular component. The mean age of the patients at operation was 67 years (35 to 89). The mean follow-up was 2.8 years (0.5 to 6.6). Pre- and post-operative assessment included Oxford hip, Short Form-12 and modified University of California Los Angeles and Merle D'Aubigne scores. The angles of inclination and anteversion of the acetabular components were measured using radiological software. There were four dislocations (0.78%), all of which were anterior. In conclusion, THR with a 22 mm diameter head performed through a posterior approach with capsular repair and using the TAL as a guide for the alignment of the acetabular component was associated with a low rate of dislocation. PMID:25183591

  10. Hip fusion as hip salvage procedure in cerebral palsy.

    PubMed

    Fucs, Patricia M De Moraes Barros; Yamada, Helder H

    2014-01-01

    The treatment of the spastic hip in Cerebral Palsy (CP) remains a challenge especially in cases of advance changes. Many options are available and the key for a good outcome is to find the best surgical procedure to an individualized patient. The hip fusion is one of the surgical options. The authors presented a group of spastic CP with painful chronic hip subluxation and dislocation treated with hip fusion with a mean follow-up period of 14.5 years. Surgical technique, post-operative management and outcomes were shown, also with the observations done regarding the evolution of the contralateral hip after the hip fusion. They concluded that the hip arthrodesis is an option for patients with spastic CP with painful subluxation or dislocated hips with the goal of pain relief maintain or improve functional status, and facilitating the care. The best candidate is a young ambulatory patient with normal contralateral hip and normal spinal alignment. PMID:25207734

  11. Hip Problems in Infants

    MedlinePlus

    ... problems that can lead to dislocation of the hip bones. This is also called dysplasia (say: "diss-play-see-uh"). This means that ... problems later in life? Source Screening for Developmental Dysplasia of the Hip by LM French, M.D., and FR Dietz, ...

  12. Total Hip Arthroplasty for Hip Fractures

    PubMed Central

    Monzón, Daniel Godoy; Iserson, Kenneth V.; Jauregui, José; Musso, Carlos; Piccaluga, Francisco; Buttaro, Martin

    2014-01-01

    Introduction: This study aimed to determine the dislocation and reoperation rate, functional outcomes, and the survival rate of the unique subset of very old but lucid and independent patients with hip fractures following a total hip arthroplasty (THA) and geriatric team-coordinated perioperative care. Method: Between 2000 and 2006, previously independent ambulatory patients ≥80 years old presenting with an intracapsular hip fracture were given THAs under the care of an integrated orthopedic surgery–geriatric service. Their fracture-related complications, ambulation, mental status, and survival were followed for 5 to 11 years postinjury. Results: Five years postinjury, 57 (61.3%) patients of the original study group were living. In all, 3 (3.2%) patients had postoperative hip dislocations (and 2 patients had dislocation twice) and 2 reoperations were needed within the first postoperative month. There were no hip dislocations or reoperations after the first year. Radiographs obtained on 88% of the surviving patients at 5 years postoperatively showed that all remained unchanged from their immediate postoperative images. Nearly half of the patients were still able to ambulate as they did preoperatively and their mixed-model equation was statistically unchanged. Conclusion: This study of patients >80 years old with previously good functional status demonstrates that with appropriate surgical (best prosthesis, good operating technique, and regional anesthesia) and geriatric (pre- and postoperative assessments, close follow-up, medication adjustments, and fall-prevention instruction) care, they have few hip dislocations and reoperations, survive postfracture at least as long as their noninjured contemporaries, and continue to function and ambulate as they did prior to their injury. PMID:24660092

  13. Fracture After Total Hip Replacement

    MedlinePlus

    ... er Total Hip Replacement cont. • Dislocation • Limb length inequality • Poor fracture healing • Repeat fracture • Lack of in- ... Surgeons (AAOS). To learn more about your orthopaedic health, please visit orthoinfo.org. Page ( 5 ) AAOS does ...

  14. [Congenital hip dysplasia, screening and therapy].

    PubMed

    Kolb, A; Windhager, R; Chiari, C

    2015-11-01

    Congenital hip dysplasia and hip dislocation are relatively common pathological conditions of the musculoskeletal system in infants. An early and certain diagnosis can now be achieved by sonographic hip screening within the framework of screening examination programs. This early diagnostic procedure in infants is essential particularly for a conservative treatment strategy. Therefore, apart from possessing in-depth knowledge, training of the examiner in specialist courses is of central importance. This article presents an overview of the entity of congenital hip dysplasia and hip dislocation, the diagnostics and treatment with special emphasis on recent developments. PMID:26489825

  15. Techniques and Results for Open Hip Preservation

    PubMed Central

    Levy, David M.; Hellman, Michael D.; Haughom, Bryan; Stover, Michael D.; Nho, Shane J.

    2015-01-01

    While hip arthroscopy grows in popularity, there are still many circumstances under which open hip preservation is the most appropriately indicated. This article specifically reviews open hip preservation procedures for a variety of hip conditions. Femoral acetabular impingement may be corrected using an open surgical hip dislocation. Acetabular dysplasia may be corrected using a periacetabular osteotomy. Acetabular protrusio may require surgical hip dislocation with rim trimming and a possible valgus intertrochanteric osteotomy. Legg–Calve–Perthes disease produces complex deformities that may be better served with osteotomies of the proximal femur and/or acetabulum. Chronic slipped capital femoral epiphysis may also benefit from a surgical hip dislocation and/or proximal femoral osteotomy. PMID:26649292

  16. Proximal femoral resection without post-operative traction for the painful dislocated hip in young patients with cerebral palsy: a review of 79 cases.

    PubMed

    Dartnell, J; Gough, M; Paterson, J M H; Norman-Taylor, F

    2014-05-01

    Proximal femoral resection (PFR) is a proven pain-relieving procedure for the management of patients with severe cerebral palsy and a painful displaced hip. Previous authors have recommended post-operative traction or immobilisation to prevent a recurrence of pain due to proximal migration of the femoral stump. We present a series of 79 PFRs in 63 patients, age 14.7 years (10 to 26; 35 male, 28 female), none of whom had post-operative traction or immobilisation. A total of 71 hips (89.6%) were reported to be pain free or to have mild pain following surgery. Four children underwent further resection for persistent pain; of these, three had successful resolution of pain and one had no benefit. A total of 16 hips (20.2%) showed radiographic evidence of heterotopic ossification, all of which had formed within one year of surgery. Four patients had a wound infection, one of which needed debridement; all recovered fully. A total of 59 patients (94%) reported improvements in seating and hygiene. The results are as good as or better than the historical results of using traction or immobilisation. We recommend that following PFR, children can be managed without traction or immobilisation, and can be discharged earlier and with fewer complications. However, care should be taken with severely dystonic patients, in whom more extensive femoral resection should be considered in combination with management of the increased tone. PMID:24788508

  17. The use of hip arthroscopy in the management of the pediatric hip.

    PubMed

    Roy, Dennis R

    2016-07-01

    Arthroscopy of the pediatric hip began in 1977 with a publication by Gross. Interest was relatively slow to develop in the 1980s and 1990s. Coupled with the success of hip arthroscopy in the adult, interest heightened in applying the procedure to a variety of pediatric hip disorders, given that the alternative was an open surgical hip dislocation. The success of this initial group of pediatric hip arthroscopist's has further expanded the application of hip arthroscopy as the primary or adjunct procedure for the management of intra-articular problems of the pediatric hip. PMID:27583144

  18. The use of hip arthroscopy in the management of the pediatric hip

    PubMed Central

    Roy, Dennis R.

    2016-01-01

    Arthroscopy of the pediatric hip began in 1977 with a publication by Gross. Interest was relatively slow to develop in the 1980s and 1990s. Coupled with the success of hip arthroscopy in the adult, interest heightened in applying the procedure to a variety of pediatric hip disorders, given that the alternative was an open surgical hip dislocation. The success of this initial group of pediatric hip arthroscopist’s has further expanded the application of hip arthroscopy as the primary or adjunct procedure for the management of intra-articular problems of the pediatric hip. PMID:27583144

  19. Infant hip sonography: current concepts.

    PubMed

    Harcke, H T; Grissom, L E

    1994-08-01

    Sonography of the infant hip has gained wide acceptance in the decade since its introduction. The two principle techniques of Graf and Harcke have been combined with the proposal of a Dynamic Standard Minimum Examination. Whereas sonography is used increasingly to manage developmental dislocation and/or displasia of the hip, there is no agreement on the use of sonography for universal newborn screening. This article describes in detail the Dynamic Standard Minimum Sonographic Examination of the infant hip. In addition, this article reviews the classification and management of infant hip disorders. PMID:7946476

  20. Subtalar dislocation

    SciTech Connect

    El-Khoury, G.Y.; Yousefzadeh, D.K.; Mulligan, G.M.; Moore, T.E.

    1982-05-01

    Over a period of three years we have seen nine patients with subtalar dislocation, all of whom sustained violent trauma to the region of the ankle and hind foot. All but one patient were males. Clinically a subtalar dislocation resembles a complicated fracture dislocation of the ankle but a definitive diagnosis can only be made radiographically. The mechanism of injury and radiographic features of this injury are discussed.

  1. Pelvic Support Osteotomy; Salvage Procedure in Chronically Dislocated Hips Case Report: Technical Note on the On-lay Bone Positioning of a Lengthening Nail and Review of the Literature

    PubMed Central

    Reynders-Frederix, Pieter; Reynders-Frederix, Cristina; Wajid, Muhammad

    2016-01-01

    Background: Young patients with a acquired dislocation of the hip with concomitant shortening of the lower limb is a difficult diagnostic problem with few definite treatment options. Methods: We used the technique, originally described by Ilizarov, with a double femur osteotomy and lengthening the femur. Lengthening was done with a sub muscular placed on-lay femur distraction rod. Distraction of the rod was done by fluid mechanics. After lengthening, the distraction was secured by a parked plate by locking the distal part of the plate. Results: This patient needed a lengthening of 60 mm, distraction time was 36 days with a distraction index of 1.61 mm per day and a healing index of 31.4 days per cm lengthening.We encountered one complication in which an exchange of the plastic feeding tube was needed at 20 days post-surgery. Conclusions: In the reported case we could improve gait with reduced limping and equalizing her leg length discrepancy. PMID:27583056

  2. Rose Hip

    MedlinePlus

    ... a chemical found in rose hip, might slow blood clotting. Taking rose hip might increase the risk of ... a chemical found in rose hip, might slow blood clotting. There is concern that rose hip might cause ...

  3. Hip pain

    MedlinePlus

    ... the bones or cartilage of your hip, including: Hip fractures – can cause sudden hip pain. These injuries can be serious and lead to major problems. Hip fractures are more common as people get older because ...

  4. Auditing hip ultrasound screening of infants at increased risk of developmental dysplasia of the hip

    PubMed Central

    Lowry, C; Donoghue, V; Murphy, J

    2005-01-01

    Background: Clinical examination, while useful, has been shown to be insufficient as the sole screening method in infants. Ultrasound examination at 8 weeks in high risk infants is an integral part of the screening process in some units. Aims: To show the efficiency of hip sonography in detection of developmental dysplasia of the hips in those without clinically dislocated hips. Methods: All infants born at the National Maternity Hospital between January 1994 and December 2001 were included. All those with clinically dislocated hips were treated by a Pavlik harness and referred for follow up to a paediatric orthopaedic surgeon. An 8 week hip ultrasound scan was performed for those infants with stable hips on examination but who met the following criteria: (1) a first degree relative with congenital dislocation of hips; (2) breech presentation at birth; and (3) a persistent "click" at birth in an otherwise stable hip. Results: During the period of study a total of 52 893 infants were born in the National Maternity Hospital. Based on the criteria above, 5485 hip ultrasound scans were performed. Of those scanned, 18 (0.33%) were found to have dislocated hips and 153 (2.78%) to have dysplasic hips. The 18 infants with dislocation were treated with Pavlik harness; the remaining 153 were followed up by serial ultrasound examinations but did not require active intervention. Conclusions: Among the population of infants at increased risk of developmental dysplasia of the hip, the hip screening programme identified 18 cases among 5485 infants; a rate of 3.2 per 1000. Hip sonography is therefore worthwhile. PMID:15908620

  5. Pathologic ligamentous constraint of the hip.

    PubMed

    Crowninshield, R D; Johnston, R C; Brand, R A; Pedersen, D R

    1983-12-01

    A mathematic model of the hip capsule and lower extremity musculature was utilized to predict the forces present in the hip ligaments during locomotion. The results demonstrate principles and trends (rather than absolute results) in hip mechanics, the details of which are affected by the associated modeling assumptions. The active stretching of a hip joint capsule tightened by scarring or surgical transfer may appreciably increase the hip contact force. Capsular elements that prevent hip flexion and adduction play a major role in hip contact force exaggeration during common activities. The positive effect of maintaining the hip capsule to reduce total hip component dislocation contrasts with the potential negative effects of restricting joint motion and increasing the joint contact force. Increased joint loading due to capsular restriction may contribute to prosthetic component loosening. PMID:6641064

  6. Hip Replacement

    MedlinePlus

    ... surgeon removes damaged cartilage and bone from your hip joint and replaces them with new, man-made parts. A hip replacement can Relieve pain Help your hip joint work better Improve walking and other movements The ...

  7. A Detailed Review of Hip Reduction Maneuvers: A Focus on Physician Safety and Introduction of the Waddell Technique

    PubMed Central

    Waddell, Bradford S.; Mohamed, Shafiq; Glomset, John Trey; Meyer, Mark S.

    2016-01-01

    Dislocation of the hip is a well-described event that occurs in conjunction with high-energy trauma or postoperatively after total hip arthroplasty. Bigelow first described closed treatment of a dislocated hip in 1870, and in the last decade many reduction techniques have been proposed. In this article, we review all described techniques for the reduction of hip dislocation while focusing on physician safety. Furthermore, we introduce a modified technique for the reduction of posterior hip dislocation that allows the physician to adhere to the back safety principles set for by the Occupational Safety and Health Administration. PMID:27114811

  8. Knee Dislocations

    PubMed Central

    Schenck, Robert C.; Richter, Dustin L.; Wascher, Daniel C.

    2014-01-01

    Background: Traumatic knee dislocation is becoming more prevalent because of improved recognition and increased exposure to high-energy trauma, but long-term results are lacking. Purpose: To present 2 cases with minimum 20-year follow-up and a review of the literature to illustrate some of the fundamental principles in the management of the dislocated knee. Study Design: Review and case reports. Methods: Two patients with knee dislocations who underwent multiligamentous knee reconstruction were reviewed, with a minimum 20-year follow-up. These patients were brought back for a clinical evaluation using both subjective and objective measures. Subjective measures include the following scales: Lysholm, Tegner activity, visual analog scale (VAS), Short Form–36 (SF-36), International Knee Documentation Committee (IKDC), and a psychosocial questionnaire. Objective measures included ligamentous examination, radiographic evaluation (including Telos stress radiographs), and physical therapy assessment of function and stability. Results: The mean follow-up was 22 years. One patient had a vascular injury requiring repair prior to ligament reconstruction. The average assessment scores were as follows: SF-36 physical health, 52; SF-36 mental health, 59; Lysholm, 92; IKDC, 86.5; VAS involved, 10.5 mm; and VAS uninvolved, 2.5 mm. Both patients had excellent stability and were functioning at high levels of activity for their age (eg, hiking, skydiving). Both patients had radiographic signs of arthritis, which lowered 1 subject’s IKDC score to “C.” Conclusion: Knee dislocations have rare long-term excellent results, and most intermediate-term studies show fair to good functional results. By following fundamental principles in the management of a dislocated knee, patients can be given the opportunity to function at high levels. Hopefully, continued advances in the evaluation and treatment of knee dislocations will improve the long-term outcomes for these patients in the

  9. 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... replace a hip joint. The device prevents dislocation in more than one anatomic plane and has...

  10. 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... replace a hip joint. The device prevents dislocation in more than one anatomic plane and has...

  11. 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... replace a hip joint. The device prevents dislocation in more than one anatomic plane and has...

  12. Rose Hip

    MedlinePlus

    ... de l’Églantier, Gulab, Heps, Hip, Hip Fruit, Hip Sweet, Hipberry, Hop Fruit, Persian Rose, Phool Gulab, Pink Rose, Poire d’oiseaux, Rosa alba, Rosa centifolia, Rosa damascena, Rosa de castillo, Rosa ... Rose Hips, Rosa lutetiana, Rosa pomifera, Rosa rugosa, Rosa villosa, ...

  13. [Hip arthroscopy].

    PubMed

    Gollwitzer, H; Banke, I J; Schauwecker, J

    2016-02-01

    Hip arthroscopy represents an important component in the treatment of diseases of the hip joint and is nowadays an indispensible tool in modern hip-preserving surgery. This article provides a review of the basic technical principles, typical indications and complications of hip arthroscopy. Furthermore, current developments as well as possibilities and limitations of the arthroscopic technique are reviewed. PMID:26781702

  14. Evaluation of the patient with hip pain.

    PubMed

    Wilson, John J; Furukawa, Masaru

    2014-01-01

    Hip pain is a common and disabling condition that affects patients of all ages. The differential diagnosis of hip pain is broad, presenting a diagnostic challenge. Patients often express that their hip pain is localized to one of three anatomic regions: the anterior hip and groin, the posterior hip and buttock, or the lateral hip. Anterior hip and groin pain is commonly associated with intra-articular pathology, such as osteoarthritis and hip labral tears. Posterior hip pain is associated with piriformis syndrome, sacroiliac joint dysfunction, lumbar radiculopathy, and less commonly ischiofemoral impingement and vascular claudication. Lateral hip pain occurs with greater trochanteric pain syndrome. Clinical examination tests, although helpful, are not highly sensitive or specific for most diagnoses; however, a rational approach to the hip examination can be used. Radiography should be performed if acute fracture, dislocations, or stress fractures are suspected. Initial plain radiography of the hip should include an anteroposterior view of the pelvis and frog-leg lateral view of the symptomatic hip. Magnetic resonance imaging should be performed if the history and plain radiograph results are not diagnostic. Magnetic resonance imaging is valuable for the detection of occult traumatic fractures, stress fractures, and osteonecrosis of the femoral head. Magnetic resonance arthrography is the diagnostic test of choice for labral tears. PMID:24444505

  15. Bipolar hip arthroplasty.

    PubMed

    Chang, Qing; Liu, Shubing; Guan, Changyong; Yu, Fangyuan; Wu, Shenguang; Jiang, Changliang

    2011-12-01

    Our aim was to compare hip arthroplasty with internal screw fixation in the repair of intertrochanteric fractures in elderly patients with osteoporosis. Of 112 included patient, 70 (81.81 ± 4.88 years) received hip arthroplasty with a prosthesis specially designed for intertrochanteric fractures, and 42 (83.46 ± 5.11 years) underwent plate-screw fixation. The hip arthroplasty group had significantly longer operation time, intraoperative blood loss, and total volume of blood transfused but had shorter time to beginning weight-bearing (5.94 ± 2.76 vs 23.68 ± 22.01 days) and higher postoperative Harris hip score (91.37 ± 4.80 vs 86.14 ± 5.46). In the arthroplasty group, there were 2 dislocations; and in the plate-screw fixation group, there were 5 internal fixation failures. Hip arthroplasty is preferable to internal fixation in elderly patients (age >80 years) with osteoporosis. PMID:21530148

  16. DYSPLASIA OF HIP DEVELOPMENT: UPDATE

    PubMed Central

    Guarniero, Roberto

    2015-01-01

    The term “developmental dysplasia of the hip” (DDH) includes a wide spectrum of abnormalities that affect the hip during its growth, ranging from dysplasia to joint dislocation and going through different degrees of coxofemoral subluxation. The incidence of DDH is variable, and depends on a number of factors, including geographical location. Approximately one in 1,000 newborn infants may present hip dislocation and around 10 in 1,000 present hip instability. Brazil has an incidence of five per 1,000 in terms of findings of a positive Ortolani sign, which is the early clinical sign for detecting the disorder. The risk factors for DDH include: female sex, white skin color, primiparity, young mother, breech presentation at birth, family history, oligohydramnios, newborns with greater weight and height, and deformities of the feet or spine. Hip examinations should be routine for newborns, and should be emphasized in maternity units. Among newborns and infants, the diagnosis of DDH is preeminently clinical and is made using the Ortolani and Barlow maneuvers. Conventional radiography is of limited value for confirming the diagnosis of DDH among newborns, and ultrasound of the hip is the ideal examination. The treatment of DDH is challenging, both for pediatric orthopedists and for general practitioners. The objectives of the treatment include diagnosis as early as possible, joint reduction and stabilization of the hip in a secure position. Classically, treatment options are divided according to different age groups, at the time of diagnosis. PMID:27022528

  17. The hip in cerebral palsy.

    PubMed

    Bleck, E E

    1980-01-01

    Orthopedic surgery can alleviate the hip flexion, adduction, and medial rotation deformities of the hip and improve the function and appearance of gait. To accomplish this, however, careful examination and prudence in the operative procedure to avoid overdoing and overcorrecting are important. Orthopedic surgery can prevent subluxation and dislocation of the hip before the age of seven years, and consequently repetitive radiographic examinations of the hip in children who have spastic paralysis of the hip musculature should be a routine procedure. Subluxation and dislocation of the hip, when established, can be successfully treated with orthopedic surgical procedures. Physicians must keep in mind that the spastic paralysis of cerebral palsy originates in the brain, and therefore the spasticity cannot be eliminated. The best that can be done is to weaken or remove some muscles as deforming forces and to achieve compromises for continued function. The goal should be optimal independence for the child and adolescent during development, and freedom from pain with deteriorating function due to degenerative arthritis in the adult. PMID:7360505

  18. Magnetic resonance imaging of hip joint cartilage and labrum

    PubMed Central

    Zilkens, Christoph; Miese, Falk; Jäger, Marcus; Bittersohl, Bernd; Krauspe, Rüdiger

    2011-01-01

    Hip joint instability and impingement are the most common biomechanical risk factors that put the hip joint at risk to develop premature osteoarthritis. Several surgical procedures like periacetabular osteotomy for hip dysplasia or hip arthroscopy or safe surgical hip dislocation for femoroacetabular impingement aim at restoring the hip anatomy. However, the success of joint preserving surgical procedures is limited by the amount of pre-existing cartilage damage. Biochemically sensitive MRI techniques like delayed Gadolinium Enhanced MRI of Cartilage (dGEMRIC) might help to monitor the effect of surgical or non-surgical procedures in the effort to halt or even reverse joint damage. PMID:22053256

  19. Hip instability.

    PubMed

    Smith, Matthew V; Sekiya, Jon K

    2010-06-01

    Hip instability is becoming a more commonly recognized source of pain and disability in patients. Traumatic causes of hip instability are often clear. Appropriate treatment includes immediate reduction, early surgery for acetabular rim fractures greater than 25% or incarcerated fragments in the joint, and close follow-up to monitor for avascular necrosis. Late surgical intervention may be necessary for residual symptomatic hip instability. Atraumatic causes of hip instability include repetitive external rotation with axial loading, generalized ligamentous laxity, and collagen disorders like Ehlers-Danlos. Symptoms caused by atraumatic hip instability often have an insidious onset. Patients may have a wide array of hip symptoms while demonstrating only subtle findings suggestive of capsular laxity. Traction views of the affected hip can be helpful in diagnosing hip instability. Open and arthroscopic techniques can be used to treat capsular laxity. We describe an arthroscopic anterior hip capsular plication using a suture technique. PMID:20473129

  20. Hip Problems

    MedlinePlus

    ... HIPS. See your doctor. Use ice and an anti-inflammatory medicine to relieve the pain. *3. Do you ... hip pain may be from ARTHRITIS. Try an anti-inflammatory medicine. If you don't feel better, see ...

  1. Hip Replacement

    MedlinePlus

    ... replacement is an operation in which a damaged hip joint is removed and replaced with an artificial joint. ... are many medical conditions that can damage the hip joint. (Watch the video to learn about what goes ...

  2. Biomechanics of the Hip Capsule and Capsule Management Strategies in Hip Arthroscopy.

    PubMed

    Nepple, Jeffrey J; Smith, Matthew V

    2015-12-01

    Recent advances in our understanding of the function of the hip capsule have clarified its importance to normal hip function and kinematics. The iliofemoral ligament is the primary stabilizing structure for controlling anterior translation and external rotation of the hip, and is violated by the arthroscopic interportal capsulotomy. Microinstability of the hip occurring after surgical trauma remains a poorly defined clinical entity. In certain at-risk populations, capsular repair should be considered as part of an arthroscopic hip procedure to achieve optimal outcomes and avoid iatrogenic instability (dislocation or microinstability). Despite a lack of conclusive evidence-based indications, we recommend capsular repair in the settings of borderline hip dysplasia (or dysplastic variants such as increased femoral anteversion), hip hypermobility, connective tissue disorders, and traumatic or atraumatic instability. With careful attention to arthroscopic capsular management, adequate exposure can be achieved and reproducibly allow for an effective capsular repair when indicated. PMID:26524549

  3. Routine Complete Capsular Closure During Hip Arthroscopy

    PubMed Central

    Harris, Joshua D.; Slikker, William; Gupta, Anil K.; McCormick, Frank M.; Nho, Shane J.

    2013-01-01

    The utility of hip arthroscopy has recently progressed beyond diagnostic to therapeutic purposes addressing central and peripheral compartment pathologies. Capsulotomy provides freedom of visualization and instrumentation. The contribution to hip stability of both dynamic and static hip structures is not fully understood. However, both basic science biomechanical and clinical outcome studies have exhibited a relevant role of the capsule in hip stability. Though rare, iatrogenic post-arthroscopy subluxation and dislocation have been reported. Therefore many surgeons have cautioned against aggressive capsulotomy or capsulectomy without repair, because of the potential for precipitation of iatrogenic hip instability. We typically perform a “T” capsulotomy and recommend complete capsular closure in conjunction with labral repair and osseous femoral and acetabular treatment. A safe, efficient, and effective method to accomplish complete capsular closure is presented to reduce iatrogenic postoperative hip instability. PMID:23875156

  4. BLEEDING OF FEMORAL HEAD DURING TOTAL HIP ARTHROPLASTY FOR OSTEOARTHROSIS

    PubMed Central

    Schwartsmann, Carlos Roberto; Spinelli, Leandro de Freitas; Sotomayor, Marco Yánez; Yépez, Anthony Kerbes; Boschin, Leonardo Carbonera; Silva, Marcelo Faria

    2015-01-01

    ABSTRACT Objective: To evaluate the bleeding of the femoral head on hip osteoarthritis in patients who underwent total hip arthroplasty. Methods: One hundred and three hips affected by primary hip osteoarthritis were evaluated. After surgical dislocation, the femoral head was divided into four quadrants, and micro perforations were made in order to observe and assess the presence of bleeding, as early type (EB), late type (LB) or without bleeding (WB). Results: We observed early bleeding (EB) in the upper quadrant in 16 hips (15.5%), late bleeding in 14 hips (13.6%) and no bleeding (WB) in 73 hips (70.9%). The anterior quadrant showed EB in 24 hips (23.3%), LB in 7 hips (6.8%) and WB in 72 hips (69.9%). The lower quadrant presented EB in 40 hips (38.8%), LB 14 hips (13.6%) and WB in 49 hips (47.6%). The posterior quadrant showed EB in 39 hips (37.9%), LB 19 hips (18.4%) and WB in 45 hips (43.7%). Comparing BMI and gender, we found no association between these parameters (p> 0.05). Conclusions: The inferior and posterior quadrant had the highest bleeding levels, following the path of the medial circumflex artery. Level of Evidence III, Therapeutic Study. PMID:26981036

  5. Articular capsule repair in initial artificial hip replacement via anterolateral approach to the hip joint.

    PubMed

    Zhang, B L; Wang, F; Tian, M B; Yin, W L; You, X Y; Li, D; Ma, L G; Xing, L Q

    2016-01-01

    This study was carried out to explore articular capsule repair in first artificial hip replacement (AHR) via anterolateral approach and its influence on postoperative dislocation. A total of 292 patients who received AHR via anterolateral approach and had the articular capsule repaired in People’s Hospital of Zhengzhou (Henan, China) from February 2008 to February 2014 were selected and divided into total hip replacement (THR) group (group A1) and artificial femoral head replacement (AFHR) group (group A2). Five hundred and five cases in the control group treated using the same approach but receiving no articular capsule repair were divided into THR group (group B1) and AFHR group (group B2). Condition of postoperative dislocation was compared between the two groups. All cases were followed up for 6 months to 5 years (average: 3.75 years); it was noted that the difference in average age, gender, disease constitution and follow-up time in the two groups was not significant (P>0.05). Moreover, groups A1 and B1 were found with 1 case of early hip joint dislocation (0.73%) and 13 cases of hip joint dislocation (5.24%) respectively post-operatively, and the comparison between the two groups was statistically significant (P less than 0.05). One case of hip joint dislocation (0.65%) was found in group A2 and 5 cases (1.95%) in group B2 in early post operation and the difference between two groups had no statistical significance (P>0.05). Neither the repair group nor the control group developed late-onset dislocation after the operation. Thus, we can state that articular capsule repair is feasible during the first AHR via anterolateral approach, which decreases the occurrence of early hip joint dislocation after operation and proves that repairing articular capsule during AFHR via anterolateral approach is unnecessary. PMID:27358130

  6. Total hip replacement for developmental dysplasia of hip and postoperative nursing.

    PubMed

    Zong, S J; Wang, F; Hu, S L

    2016-01-01

    This study was designed to determine the clinical effect of total hip replacement for the treatment of developmental dysplasia of the hip (DDH) and analyze the postoperative nursing. Sixty patients (78 hips) aged 18-75 years (average 58.6±2.31 years) who received total hip replacement for treatment of DDH at the Zhengzhou People’s Hospital, Henan, China, from April 2013 to June 2016 were selected as research subjects. Twenty-four patients were male (30 hips) and 36 were female (48 hips). Of the 60 patients, according to Crowe typing, 24 were type I (30 hips), 26 were type II (34 hips), 6 were type III (8 hips) and 4 were type IV (6 hips). According to the Harris hip score system, the score of all hips was 39.46±3.56 points average (18-56 points) before treatment and resulted as 89.60±4.25 points (79-98 points) at the last follow-up, showing a statistically significant difference (P < 0.05). Complications such as wound infection, dislocation, fracture of femoral shaft, femoral nerve and injury of sciatic nerve were not found after treatment. A total of 48 cases (58 hips) obtained excellent curative results (93.33% recovery), 8 cases (14 hips) good (92.31% recovery), and 4 cases (6 hips) medium. Total hip replacement proved to be effective in treating DDH and secondary osteoarthritis. Moreover, soft tissue release and an optimum degree recovery of anatomic form and physiological function of the diseased hip is an important basis for reconstructing the acetabulum and stabilizing acetabulum prosthesis. PMID:27049089

  7. Framing Hip Hop: New Methodologies for New Times

    ERIC Educational Resources Information Center

    Dimitriadis, Greg

    2015-01-01

    This article revisits the central impulse behind early advocacy for ethnographic approaches to hip hop--that critics should try as much as possible to limit their own certainties around what hip hop can and might mean. While ethnographic approaches can engender the kinds of personal dislocations that allow for this negotiation, they do not…

  8. Dual mobility in total hip arthroplasty.

    PubMed

    Plummer, Darren R; Haughom, Bryan D; Della Valle, Craig J

    2014-01-01

    Dual-mobility articulations have shown promising results. Postoperative instability remains the most common reason for revision of a total hip arthroplasty (THA). Dual-mobility cups have been shown to decrease the rate of dislocation in primary THA and have been used to treat and prevent instability in revision THA. Greater range of motion and a greater head-to-neck ratio and a greater jump distance are achieved, resulting in a lower risk of instability. Concerns with dual-mobility cups include wear and intraprosthetic dislocation. Specific design modifications have aimed to improve cup fixation and decrease polyethylene wear and the risks of intraprosthetic dislocation. PMID:24267202

  9. Dislocation Creep in Magnesium Calcite

    NASA Astrophysics Data System (ADS)

    Xu, L.; Xiao, X.; Evans, B. J.

    2003-12-01

    To investigate the effect of dissolved Mg on plastic deformation of calcite, we performed triaxial deformation experiments on synthetic calcite with varying amount of Mg content. Mixtures of powders of calcite and dolomite were isostatically hot pressed (HIP) at 850° C and 300 MPa confining pressure for different intervals (2 to 20hrs) resulting in homogeneous aggregates of high-magnesium calcite; Mg content varied from 0.07 to 0.17 mol%. Creep tests were performed at differential stresses from 20 to 160 MPa at 700 to 800° C. Grain sizes before and after deformation were determined from the images obtained from scanning electron microscope (SEM) and optical microscope. Grain sizes are in the range of 5 to 20 microns depending on the HIP time, and decrease with increasing magnesium content. Both BSE images and chemical analysis suggest that all dolomite are dissolved and the Mg distribution is homogeneous through the sample, after 2 hrs HIP. At stresses below 40 MPa, the samples deformed in diffusion region (Coble creep), as described previously by Herwegh. The strength decreases with increasing magnesium content, owing to the difference of grain size. At stresses above 80 MPa, the stress exponent is greater than 3, indicating an increased contribution of dislocation creep. The transition between diffusion to dislocation creep occurs at higher stresses for the samples with higher magnesium content and smaller grain size. Preliminary data suggests a slight increase in strength with increasing magnesium content, but more tests are needed to verify this effect. In a few samples, some strain weakening may have been evident. The activation energy in the transition region (at 80 MPa) is ˜200 KJ/mol with no dependence on magnesium content, agreeing with previous measurements of diffusion creep in natural and synthetic marbles.

  10. Evaluation of the hip center in total hip arthroplasty for old developmental dysplasia.

    PubMed

    Flecher, Xavier; Parratte, Sebastien; Brassart, Nicolas; Aubaniac, Jean-Manuel; Argenson, Jean-Noël

    2008-12-01

    We describe the problems with positioning the hip center according to the severity of dislocation in 97 cementless total hip arthroplasty for developmental dysplasia of the hip. The mean location of the hip center from the interteardrop was 30.4 +/- 8.7 mm horizontally and 23.4 +/- 5.4 mm vertically. The presence of a limp correlated with a superior placement of the cup. Four cups were revised, 2 of which with a significant high hip center. The survival rate of the acetabular component was 95% at 12 years. Craniopodal repositioning was easy in class 1. In class 2, the cup was the largest. In class 3, the greatest variations of the hip center were found. In class 4, the smallest implants were necessary for positioning in the true acetabulum. PMID:18534475

  11. Resurfacing hip arthroplasty in neuromuscular hip disorders – A retrospective case series

    PubMed Central

    Tudor, Francois; Ariamanesh, Amir; Potty, Anish; Hashemi-Nejad, Aresh

    2013-01-01

    Background Management of the degenerate hip in patients with neuromuscular conditions should be aimed at improving quality of life and ease of nursing care. Arthroplasty poses a significant challenge with predisposition to dislocation and loosening due to anatomical abnormalities, soft tissue contractures and impaired muscle tone. Methods We present a series of 11 hips (9 patients) following total hip resurfacing arthroplasty for painful osteoarthritis in patients with differing neuromuscular conditions. Patients were assessed clinically and radiographically and also for satisfaction of their carers due to improved ability to provide nursing care. Mean patient age was 33.1 years (range 13–49 years) with mean follow up at publication 63.7 months (41–89 months). All patients were operated by a single surgeon (AHN) and received the required post operative care and physiotherapy. Soft tissue releases were performed when necessary. All hips were assessed clinically and radiographically at 6 weeks and 6 months and 1 year post-operatively. Six month follow-up also included a questionnaire with scoring of care-provider satisfaction. Results Ten hips had good clinical results with improvement in pain and function and radiologically showed no signs of loosening. One hip required revision to proximal femoral excision due to dislocation and loose acetabular component with severe pain. None of the other hips dislocated. Analysis of care provider satisfaction assessing ability to provide personal care, positioning and transferring, comfort, interaction and communication scored excellent to good in 10 patients and satisfactory in one. Conclusion We believe hip resurfacing arthroplasty to be a viable option in the treatment of the complex problem of osteoarthritis in the hips of patients with neuromuscular disease. The improved biomechanics confer greater stability when compared to conventional total hip arthroplasty. Although technically demanding, a successful result has

  12. Dislocation motion and instability

    NASA Astrophysics Data System (ADS)

    Zhu, Yichao; Chapman, Stephen Jonathan; Acharya, Amit

    2013-08-01

    The Peach-Koehler expression for the stress generated by a single (non-planar) curvilinear dislocation is evaluated to calculate the dislocation self stress. This is combined with a law of motion to give the self-induced motion of a general dislocation curve. A stability analysis of a rectilinear, uniformly translating dislocation is then performed. The dislocation is found to be susceptible to a helical instability, with the maximum growth rate occurring when the dislocation is almost, but not exactly, pure screw. The non-linear evolution of the instability is determined numerically, and implications for slip band formation and non-Schmid behavior in yielding are discussed.

  13. Dislocated shoulder - aftercare

    MedlinePlus

    Shoulder dislocation - aftercare; Shoulder subluxation - aftercare; Shoulder reduction - aftercare ... You most likely dislocated your shoulder from a sports injury or accident, such as a fall. You have likely injured (stretched or torn) some of the muscles, ...

  14. Dislocated shoulder - aftercare

    MedlinePlus

    Shoulder dislocation - aftercare; Shoulder subluxation - aftercare; Shoulder reduction - aftercare ... Horn AE, Ufberg JW. Management of common dislocations. In: ... Extremity 6th ed. Philadelphia, PA: ElsevierMosby; 2011:chap 92.

  15. Temporomandibular joint dislocation.

    PubMed

    Sharma, Naresh Kumar; Singh, Akhilesh Kumar; Pandey, Arun; Verma, Vishal; Singh, Shreya

    2015-01-01

    Temporomandibular joint (TMJ) dislocation is an uncommon but debilitating condition of the facial skeleton. The condition may be acute or chronic. Acute TMJ dislocation is common in clinical practice and can be managed easily with manual reduction. Chronic recurrent TMJ dislocation is a challenging situation to manage. In this article, we discuss the comprehensive review of the different treatment modalities in managing TMJ dislocation. PMID:26668447

  16. Temporomandibular joint dislocation

    PubMed Central

    Sharma, Naresh Kumar; Singh, Akhilesh Kumar; Pandey, Arun; Verma, Vishal; Singh, Shreya

    2015-01-01

    Temporomandibular joint (TMJ) dislocation is an uncommon but debilitating condition of the facial skeleton. The condition may be acute or chronic. Acute TMJ dislocation is common in clinical practice and can be managed easily with manual reduction. Chronic recurrent TMJ dislocation is a challenging situation to manage. In this article, we discuss the comprehensive review of the different treatment modalities in managing TMJ dislocation. PMID:26668447

  17. Hip arthroscopy

    MedlinePlus

    Johnson D, Weiss WM. Basic arthroscopic principles. In: Miller MD, Thompson SR, eds. DeLee and Drez's Orthopaedic ... 11. Sanchez VMI, Meza AO. Hip arthroscopy. In: Miller MD, Thompson SR, eds. DeLee and Drez's Orthopaedic ...

  18. Hip arthroscopy☆

    PubMed Central

    de Amorim Cabrita, Henrique Antônio Berwanger; de Castro Trindade, Christiano Augusto; de Campos Gurgel, Henrique Melo; Leal, Rafael Demura; de Souza Marques, Ricardo da Fonseca

    2014-01-01

    Hip arthroscopy is a safe method for treating a variety of pathological conditions that were unknown until a decade ago. Femoroacetabular impingement is the commonest of these pathological conditions and the one with the best results when treated early on. The instruments and surgical technique for hip arthroscopy continue to evolve. New indications for hip arthroscopy has been studied as the ligamentum teres injuries, capsular repair in instabilities, dissection of the sciatic nerve and repair of gluteal muscles tears (injuries to the hip rotator cuff), although still with debatable reproducibility. The complication rate is low, and ever-better results with fewer complications should be expected with the progression of the learning curve. PMID:26229924

  19. Hip ultrasound.

    PubMed

    Martinoli, Carlo; Garello, Isabella; Marchetti, Alessandra; Palmieri, Federigo; Altafini, Luisa; Valle, Maura; Tagliafico, Alberto

    2012-12-01

    In newborns, US has an established role in the detection and management of developmental dysplasia of the hip. Later in childhood, when the limping child is a major diagnostic dilemma, US is extremely helpful in the identification of the varied disease processes underlying this condition, as transient synovitis, septic arthritis, Perthes disease and slipped femoral capital epiphysis. In adolescent practicing sporting activities, US is an excellent means to identify apophyseal injures about the pelvic ring, especially when avulsions are undisplaced and difficult-to-see radiographically. Later on, in the adulthood, US is an effective modality to diagnose tendon and muscle injuries about the hip and pelvis, identify effusion or synovitis within the hip joint or its adjacent bursae and guide the treatment of these findings. The aim of this article is to provide a comprehensive review of the most common pathologic conditions about the hip, in which the contribution of US is relevant for the diagnostic work-up. PMID:21571471

  20. Hip flexor strain - aftercare

    MedlinePlus

    Pulled hip flexor - aftercare; Hip flexor injury - aftercare; Hip flexor tear - aftercare; Iliopsoas strain - aftercare; Strained iliopsoas muscle - aftercare; Torn iliopsoas muscle - aftercare; Psoas strain - aftercare

  1. Hip Implant Systems

    MedlinePlus

    ... hip replacement surgery, the damaged portions of the hip joint are removed. The ball (femoral head) is removed ... hip or leg Swelling at or near the hip joint A limp or change in walking ability Noise ( ...

  2. 'Hip' pain.

    PubMed

    Zacher, Josef; Gursche, Angelika

    2003-02-01

    'Hip' pain is usually located in the groin, upper thigh or buttock and is a common complaint. Slipped capital femoral epiphysis, avascular femoral head necrosis and apophyseal avulsion are the most common diagnoses in childhood and adolescents. Strains and fractures are common in sport-active adults. Osteoarthritis occurs in middle-aged and older adults. Trauma may result in femoral head fracture or typical muscle and tendon sprains and bursitis. Septic or inflammatory arthritis can occur at every age. Septic arthritis, fractures and acute epiphyseal slipping are real emergency cases. Congenital dysplasia of the hip joint may lead to labral tears and early osteoarthritis. The most important hip problems in children, adolescents, adult and older people are discussed; these problems originate from intra-articular disorders and the surrounding extra-articular soft tissues. Medical history, clinical examination and additional tests, including imaging, will be demonstrated. Principles of treatment are given for specific disorders. PMID:12659822

  3. Hip Instability: Current Concepts and Treatment Options.

    PubMed

    Dumont, Guillaume D

    2016-07-01

    Instability of the hip can manifest in a wide range of settings, with presenting symptoms including subtle discomfort at end range of motion or more dramatic dislocation of the joint. It can result from traumatic injury with dislocation or subluxation; atraumatic capsular laxity; structural bony abnormality, such as acetabular dysplasia; and iatrogenic injury. Initial treatment of the concentrically reduced joint often begins with physical therapy to strengthen dynamic stabilizers and to allow time for resolution of acute symptoms. Surgical treatment is aimed at repairing injured soft tissue structures, including static stabilizers, and addressing underlying bony structural deficiencies. PMID:27343395

  4. Dislocation Formation in Alloys

    NASA Astrophysics Data System (ADS)

    Minami, Akihiko; Onuki, Akira

    2006-05-01

    An interaction between dislocations and phase transitions is studied by a phase field model both in two and three dimensional systems. Our theory is a simple extension of the traditional linear elastic theory, and the elastic energy is a periodic function of local strains which is reflecting the periodicity of crystals. We find that the dislocations are spontaneously formed by quenching. Dislocations are formed from the interface of binary alloys, and slips are preferentially gliding into the soft metals. In three dimensional systems, formation of dislocations under applied strain is studied in two phase state. We find that the dislocation loops are created from the surface of hard metals. We also studied the phase separation above the coexisting temperature which is called as the Cottrell atmosphere. Clouds of metals cannot catch up with the motion of dislocations at highly strained state.

  5. Hip arthroscopy for the management of trauma: a literature review

    PubMed Central

    Newman, Justin T.; Saroki, Adriana J.; Philippon, Marc J.

    2015-01-01

    The first descriptions of the use of hip arthroscopy for traumatic injuries were presented in 1980. One paper described arthroscopy for the removal of a bullet fragment while others reported using hip arthroscopy to remove fragments following total hip arthroplasty. With the application of traction and modification of arthroscopic instruments, hip arthroscopy has become a useful tool in treating trauma to the hip. Most of the literature describes traumatic hip dislocation. Several studies have documented the successful use of arthroscopy for removal of loose bodies, but it has also been used to treat labral tears, chondral defects and acetabular rim fractures. Complications reported include fluid extravasation, the lowering of the patient's body temperature using cool saline irrigation and further injury due to unrecognized concomitant pathology. PMID:27011845

  6. Intra-operative femoral neck fracture during attempted dislocation of a reduced hemi-arthroplasty.

    PubMed

    Ling, Samuel Ka Kin; Ma, Chun Man; Lui, Tun Hing

    2015-05-01

    Fragility hip fractures are increasingly common and hemiarthroplasty is one of the standard treatments. Although a common surgery, it should be performed with great caution because of the poor premorbid and bone quality in this demographic. Intra-operative fractures can occur while attempting press fit of the femoral implant. However; vigilance often steps down once the implant is secured and the hip reduced. This case report reminds surgeons that a large amount of torque can be transmitted during intra-operative positioning, such as during an attempt of hip dislocation. This torque, in addition to the risk factor of osteoporotic bone, can result in iatrogenic fractures. Published literature regarding management of an intra-operative fracture while the prosthetic hip is still reduced is lacking. The authors propose that temporary prophylactic cerclage wiring is a prudent and safe procedure prior to hip dislocation. PMID:26058283

  7. Surgical Management of Hip Problems in Myelomeningocele: A Review Article

    PubMed Central

    Baghdadi, Taghi; abdi, Reza; Bashi, Ramin Zargar; Aslani, Hossein

    2016-01-01

    Background: Children with myelomeningocele (MMC) develop a wide variety of hip deformities such as muscle imbalance, contracture, subluxation, and dislocation. Various methods and indications have been introduced for treatment of muscle imbalances and other hip problems in patients with MMC but there is no study or meta-analysis to compare the results and complications. This review aims to find the most acceptable approach to hip problems in patients with MMC. Methods: MEDLINE was searched up to April 2015. All study designs that reported on the outcomes of hip problems in MMC were included. From 270 screened citations, 55 were strictly focused on hip problem in MMC were selected and reviewed. Results: Complex osseous and soft tissue reconstructive procedures to correct hip dysplasia and muscle balancing around the hip are rarely indicated for MMC patients without good quadriceps power. Conclusion: Over the years a consensus on the best algorithm for treatment of hip dislocation in myelomeningocele has been missing, however, muscular balancing with/out osseous procedure seems a reasonable approach especially in unilateral mid-lumbar MMC. PMID:27517062

  8. Metallurgy: Starting and stopping dislocations

    NASA Astrophysics Data System (ADS)

    Minor, Andrew M.

    2015-09-01

    A comparison of dislocation dynamics in two hexagonal close-packed metals has revealed that dislocation movement can vary substantially in materials with the same crystal structure, associated with how the dislocations relax when stationary.

  9. The Anterior Approach for Total Hip Replacement.

    PubMed

    Hochfelder, Jason P; Davidovitch, Roy I

    2016-03-01

    The anterior approach for total hip replacements has recently gained popularity. Some authors report faster recoveries and decreased dislocation rated with no increased risk of complications. However others claim no difference in outcomes when compared to other approaches yet an increase in complication rates. This paper provides a brief history of the approach, discusses various indications and contraindications, preoperative considerations, surgical techniques, and postoperative protocols. PMID:26977549

  10. Dislocation in Spoken French.

    ERIC Educational Resources Information Center

    Calve, Pierre

    1985-01-01

    Discusses dislocation, a construction in which one element, usually a noun, is isolated either at the beginning or at the end of a sentence while being represented in the body of the sentence by a pronoun. Discusses the place of dislocation in linguistic studies and its pedagogical implications. (SED)

  11. Dislocations in yttrium orthovanadate

    NASA Astrophysics Data System (ADS)

    Eakins, D. E.; LeBret, J. B.; Norton, M. G.; Bahr, D. F.

    2004-06-01

    Dislocation structures in single crystals of yttrium orthovanadate have been identified by transmission electron microscopy. Electron diffraction was used to predict possible Burgers vectors for the dislocations. Results suggest vectors of the type {1}/{2}[1 1 1] or {1}/{4}[0 2 1] . Arguments for the likelihood of each possible vector have been presented.

  12. Parallel Dislocation Simulator

    Energy Science and Technology Software Center (ESTSC)

    2006-10-30

    ParaDiS is software capable of simulating the motion, evolution, and interaction of dislocation networks in single crystals using massively parallel computer architectures. The software is capable of outputting the stress-strain response of a single crystal whose plastic deformation is controlled by the dislocation processes.

  13. Combined Anterior and Posterior Approach in Total Hip Arthroplasty for Crowe IV Dysplasia or Ankylosed Hips.

    PubMed

    Lee, Young-Kyun; Kim, Ki-Choul; Ha, Yong-chan; Koo, Kyung-Hoi

    2015-05-01

    We evaluated 70 patients (71 hips) who underwent complex total hip arthroplasty (THA) through the combined anterior and posterior approach. Sixty-five patients (32 dislocated hips and 34 ankylosed hips) were followed-up at a minimum of 3 years (median, 6 years; range, 3-10 years). Seven patients (10.6%), who had transient paresthesia on the anterior thigh, recovered within 3 months. All patients had a good clinical outcome in terms of range of motion, pain and recovery of walking. At the latest follow-up, all prostheses had bone-ingrown stability without any detectable wear or osteolysis. The combined approach allows an excellent exposure of the acetabulum for accurate cup alignment, leg lengthening and mobilization of joint in complex THA without trochanteric osteotomy, excessive abductor release and femoral shortening osteotomy. PMID:25682205

  14. Relative head size increase using an anatomic dual mobility hip prosthesis compared to traditional hip arthroplasty: impact on hip stability.

    PubMed

    D'Apuzzo, Michele R; Nevelos, Jim; Yeager, Alyssa; Westrich, Geoffrey H

    2014-09-01

    Smaller head sizes and head/cup ratios make cups smaller than 50mm and larger than 58mm, more prone to dislocation. Using computer modeling, we compared average head sizes and posterior horizontal dislocation distance (PHDD) in two 78-patient matched cohorts. Cup sizes were small (≤50mm) or large (≥58mm). The control cohort had conventional fixed bearing prostheses, while the experimental cohort had anatomical dual mobility (ADM) hip prostheses. ADM cups have larger average head sizes and PHDD than traditional fixed bearing prostheses by 11.5mm and 80% for cups ≤50mm, and 16.3mm and 90% for cups ≥58mm. Larger head sizes and increased head/cup ratio may allow the ADM prosthesis to reduce the incidence of dislocation. PMID:24997653

  15. Electromechanical simulations of dislocations

    NASA Astrophysics Data System (ADS)

    Skiba, Oxana; Gracie, Robert; Potapenko, Stanislav

    2013-04-01

    Improving the reliability of micro-electronic devices depends in part on developing a more in-depth understanding of dislocations because dislocations are barriers to charge carriers. To this end, the quasi-static simulation of discrete dislocations dynamics in materials under mechanical and electrical loads is presented. The simulations are based on the extended finite element method, where dislocations are modelled as internal discontinuities. The strong and weak forms of the boundary value problem for the coupled system are presented. The computation of the Peach-Koehler force using the J-integral is discussed. Examples to illustrate the accuracy of the simulations are presented. The motion of the network of the dislocations under different electrical and mechanical loads is simulated. It was shown that even in weak piezoelectric materials the effect of the electric field on plastic behaviour is significant.

  16. Electronic properties of dislocations

    NASA Astrophysics Data System (ADS)

    Reiche, M.; Kittler, M.; Uebensee, H.; Pippel, E.; Haehnel, A.; Birner, S.

    2016-04-01

    Dislocations exhibit a number of exceptional electronic properties resulting in a significant increase in the drain current of MOSFETs if defined numbers of these defects are placed in the channel. Measurements on individual dislocations in Si refer to a supermetallic conductivity. A model of the electronic structure of dislocations is proposed based on experimental measurements and tight-binding simulations. It is shown that the high strain level on the dislocation core—exceeding 10 % or more—causes locally dramatic changes in the band structure and results in the formation of a quantum well along the dislocation line. This explains experimental findings (two-dimensional electron gas, single-electron transitions). The energy quantization within the quantum well is most important for supermetallic conductivity.

  17. Constrained components for the unstable hip following total hip arthroplasty: a literature review

    PubMed Central

    Ragland, P. S.; Clarke, S.

    2006-01-01

    Patients with chronic instability or late dislocation following total hip arthroplasty often require operative management. Unfortunately, there is an increased risk of recurrent dislocation following revision in these patients. Over the past decade the use of constrained devices for patients with chronic instability has gained increased interest; however, there is a paucity of studies available in the literature regarding the use of these devices. The purpose of this study was to analyze the available literature over the past 15 years, focusing on larger, long-term studies, to obtain recommendations from the respective articles for indications and contraindications for the use of constrained devices. Our review of eight reports included 1,199 hips in 1,148 patients with a total mean follow-up of 51 months (range, 24 to 124 months). The mean rate of dislocation following revision with a constrained liner was 10% and the mean re-operation rate for reasons other than dislocation was 4%. We concluded that constrained liners are an option for patients who have failed management of instability with other implants, those with instability of unclear etiology, those with cognitive problems who are unable to follow dislocation precautions, those with deficient abductors, and elderly or low-demand individuals with well-positioned implants requiring revision. PMID:16927089

  18. Evidence-based management of developmental dysplasia of the hip.

    PubMed

    Cooper, Anthony Philip; Doddabasappa, Siddesh Nandi; Mulpuri, Kishore

    2014-07-01

    Developmental Dysplasia of the Hip (DDH) refers to a spectrum of abnormalities involving the developing hip. These abnormalities range from mild instability to frank dislocation of the joint. It is important to treat the condition effectively in order to encourage the hip to develop normally and produce good long-term results. This article reviews the evidence related to the treatment of DDH. The quality of evidence for DDH management remains low, with little uniformity in terminology and most studies being retrospective in nature. Given this, it is not possible to recommend or reject most treatment modalities based on existing studies. PMID:24975762

  19. Bilateral posterior sternoclavicular dislocation.

    PubMed

    Baumann, Matthias; Vogel, Tobias; Weise, Kuno; Muratore, Tim; Trobisch, Per

    2010-07-01

    Posterior sternoclavicular dislocations are a rare injury, representing <5% of all sternoclavicular dislocations and 1 in 1600 shoulder girdle injuries. Proper imaging with computed tomography and prompt diagnosis are essential steps in preventing potentially lethal complications observed in approximately 3% of all posterior sternoclavicular dislocations. Surgical treatment is necessary if closed reduction fails. With the medial clavicular epiphysis being the last to close (between ages 22 and 25), children and adolescents typically present with epiphyseal fractures rather than joint dislocations. If closed reduction fails, open reduction and internal fixation (ORIF) should be considered in fractures, whereas complex reconstructions with tendon graft procedures have been recommended for joint dislocations. This article presents a case of a traumatic bilateral posterior sternoclavicular dislocation due to an epiphyseal fracture in a 15-year-old boy. To our knowledge, this is the first reported case of a bilateral posterior sternoclavicular dislocation. Attempted closed reduction failed with redislocation after 2 days. The patient subsequently required ORIF. This article describes our technique with anterior retraction of the medial clavicle, closure of the posterior periosteum, and ORIF using nonabsorbable sutures. Postoperative shoulder mobilization was started on day 1. At final follow-up, the patient was completely asymptomatic. PMID:20608625

  20. Cup positioning in total hip arthroplasty.

    PubMed

    Scheerlinck, T

    2014-09-01

    The "optimal" positioning of the cup in total hip arthroplasty can improve hip function and reduce wear, impingement and dislocation. The cup position is described as the spatial relation between the hip rotation centre and the pelvis and, as the cup orientation around the rotation centre. The first parameter affects hip balance and, if not managed properly, might result in poor function and leg length discrepancy. The second parameter is often "silent", unless impingement or dislocation occurs. However, inappropriate cup orientation can accelerate wear and cause early failure. As such, it is mandatory to get both right, taking into account multiple parameters: the stem position, the approach, the bearing surface, the cup coverage and the pelvic orientation during loading. In most cases a "standard" cup position is adequate. However, specific anatomic features might require an individualized approach. This paper aims at reviewing the parameters that impact on the optimal cup position. This should allow for more judicious choices in those particular cases. PMID:26280607

  1. A reappraisal of the Ortolani examination in children with developmental dysplasia of the hip.

    PubMed

    Lipton, Glenn E; Guille, James T; Altiok, Haluk; Bowen, J Richard; Harcke, H Theodore

    2007-01-01

    The Ortolani maneuver is currently accepted as an accurate test to detect developmental dislocation of the hip. However, the clinical sign does not always correlate with the findings seen on ultrasound. The ultrasound-documented position of the femoral head was correlated with the result of the clinical Ortolani examination to better understand the value and validity of the Ortolani test. Two populations were compared: hips with a positive Ortolani sign and hips with a negative Ortolani sign but with an ultrasound-documented dislocated hip. In the Ortolani-positive group, there were 45 patients (53 affected hips), and in the Ortolani-negative group, there were 24 patients (25 dislocated hips). Position of the femoral head at rest, side of involvement, and sex showed no significant difference between the Ortolani-positive and -negative groups. Mean age of patients in the Ortolani-positive group was less (mean, 28 days) and was statistically different (P < 0.05) from those in the Ortolani-negative group (mean, 91 days). In conclusion, dislocated hips that show similar femoral head movement can produce an Ortolani-positive examination in a younger patient and an Ortolani-negative examination in an older patient. The classic clinical method described by Ortolani for detecting hip dislocation in which the thigh of the affected hip is abducted and the femoral head was thought to be reducing into the acetabulum can be erroneous. All Ortolani-positive hips were abnormal, as the sensation characteristic of a positive Ortolani examination may be felt without full reduction and, in some cases, with no reduction, as documented by ultrasound. PMID:17195793

  2. Septic arthritis of the hip - current concepts.

    PubMed

    Rutz, E; Brunner, R

    2009-01-01

    Septic arthritis of the hip is the commonest septic condition during growth, reaching a distinct peak in frequency during infancy. The aetiology is a haematogenous joint infection. Indicative signs are severe pain when moving the joint, septic appearance and a poor general condition of these small and young patients. The diagnosis often can be difficult in infants since septic temperatures are not always present. An ultrasound scan shows the hip joint effusion and the capsular distension. X-ray investigation helps to exclude defective situations. Therapeutic options are: in patients with short history without radiologically visible complications we recommend repeated arthroscopic irrigation and in patients with long history and a radiologically visible defect of the femoral head or dislocation we recommend arthrotomy and open revision or reduction of the hip joint. PMID:19306242

  3. Avoiding Hip Instability and Limb Length Discrepancy After Total Hip Arthroplasty.

    PubMed

    Sculco, Peter K; Cottino, Umberto; Abdel, Matthew P; Sierra, Rafael J

    2016-04-01

    Two complications after total hip arthroplasty (THA) are hip instability and limb length discrepancy; instability is a common indication for revision THA. The goal of a successful THA is to maximize impingement-free range of motion, recreate appropriate offset, and equalize limb length discrepancies to produce a pain-free and dynamically stable THA. In this article, the patient risk factors for dislocation and limb length discrepancy, key elements of the preoperative template, the anatomic landmarks for accurate component placement, the leg positions for soft tissue stability testing, and the management of postoperative instability are reviewed. PMID:26772941

  4. Total hip replacement in dancers.

    PubMed

    Buyls, Inge R A E; Rietveld, A B M Boni; Ourila, Tiia; Emerton, Mark E; Bird, H A

    2013-04-01

    A case report of a professional contemporary dancer who successfully returned to the stage after bilateral total hip replacements (THR) for osteoarthritis is presented, together with her own commentary and a retrospective cohort study of total hip replacements in dancers. In the presented cohort, there were no post-operative dislocations or infections, the original pain had been relieved, rehabilitation was objectively normal and all resumed their dance (teaching) activities. Nevertheless, they were disappointed about the prolonged rehabilitation. Due to their high demands as professional dancers, post-operative expectations were too optimistic in view of the usual quick and favourable results of THR in the older and less physically active, general population. In all dancers with unilateral osteoarthritis, the left hip was involved, which may reflect the tendency to use the left leg as standing leg and be suggestive that strenuous physical activity may lead to osteoarthritis. Better rehabilitation guidelines are needed for dancer patients undergoing THR, especially drawing their attention to realistic post-operative expectations. PMID:23588878

  5. Anterior Longitudinal Osteotomy of the Greater Trochanter in Total Hip Arthroplasty.

    PubMed

    Surace, Michele F; Regazzola, Gianmarco M V; Vulcano, Ettore; Monestier, Luca; Cherubino, Paolo

    2015-08-01

    The extra-articular impingement of the greater trochanter against the ileum is an underrated cause of early dislocation in total hip arthroplasty. In this preliminary study, the authors assess the effectiveness of an anterior longitudinal osteotomy of the greater trochanter for preventing dislocation. A total of 115 patients underwent a total hip arthroplasty through a posterolateral approach. All patients underwent clinical and radiological follow-up at 1, 3, and 6 months. No dislocation was reported. All patients demonstrated fast recovery of range of motion and walking. No trochanter fractures were observed. The osteotomy of the greater trochanter is an effective surgical technique that decreases anterior impingement and consequently lowers the dislocation rate in primary total hip arthroplasty. [Orthopedics. 2015; 38(8):490-493.]. PMID:26313167

  6. Characteristics of children with hip displacement in cerebral palsy

    PubMed Central

    Hägglund, Gunnar; Lauge-Pedersen, Henrik; Wagner, Philippe

    2007-01-01

    Background Hip dislocation in children with cerebral palsy (CP) is a common and severe problem. The dislocation can be avoided, by screening and preventive treatment of children with hips at risk. The aim of this study was to analyse the characteristics of children with CP who develop hip displacement, in order to optimise a hip surveillance programme. Methods In a total population of children with CP a standardised clinical and radiological follow-up of the hips was carried out as a part of a hip prevention programme. The present study is based on 212 children followed until 9–16 years of age. Results Of the 212 children, 38 (18%) developed displacement with Migration Percentage (MP) >40% and further 19 (9%) MP between 33 and 39%. Mean age at first registration of hip displacement was 4 years, but some hips showed MP > 40% already at two years of age. The passive range of hip motion at the time of first registration of hip displacement did not differ significantly from the findings in hips without displacement. The risk of hip displacement varied according to CP-subtype, from 0% in children with pure ataxia to 79% in children with spastic tetraplegia. The risk of displacement (MP > 40%) was directly related to the level of gross motor function, classified according to the gross motor function classification system, GMFCS, from 0% in children in GMFCS level I to 64% in GMFCS level V. Conclusion Hip displacement in CP often occurs already at 2–3 years of age. Range of motion is a poor indicator of hips at risk. Thus early identification and early radiographic examination of children at risk is of great importance. The risk of hip displacement varies according to both CP-subtype and GMFCS. It is sometimes not possible to determine subtype before 4 years of age, and at present several definitions and classification systems are used. GMFCS is valid and reliable from 2 years of age, and it is internationally accepted. We recommend a hip surveillance programme for

  7. GPU accelerated dislocation dynamics

    NASA Astrophysics Data System (ADS)

    Ferroni, Francesco; Tarleton, Edmund; Fitzgerald, Steven

    2014-09-01

    In this paper we analyze the computational bottlenecks in discrete dislocation dynamics modeling (associated with segment-segment interactions as well as the treatment of free surfaces), discuss the parallelization and optimization strategies, and demonstrate the effectiveness of Graphical Processing Unit (GPU) computation in accelerating dislocation dynamics simulations and expanding their scope. Individual algorithmic benchmark tests as well as an example large simulation of a thin film are presented.

  8. Common questions about developmental dysplasia of the hip.

    PubMed

    Jackson, Jonathan C; Runge, Melissa M; Nye, Nathaniel S

    2014-12-15

    Developmental dysplasia of the hip is a common musculoskeletal condition in newborns. Infants with developmental dysplasia of the hip, whether treated or untreated, have a higher incidence of early-onset hip osteoarthritis in adulthood. Evidence to support universal screening by physical examination or ultrasonography is limited and often conflicting. The U.S. Preventive Services Task Force found insufficient evidence that screening for developmental dysplasia of the hip prevents adverse outcomes. Physical examination screening is recommended by the American Academy of Pediatrics and the Pediatric Orthopaedic Society of North America. These organizations recommend use of the Ortolani and Barlow maneuvers to screen infants up to three months of age. Several recent studies support starting assessment for limited hip abduction at eight weeks of age, which is the most sensitive test for developmental dysplasia of the hip from this age on. Infants with overtly dislocated or dislocatable hips should be referred to an orthopedist on a priority basis at the time of diagnosis. Infants with equivocal hip examination findings at birth can be reexamined in two weeks. If there is subluxation or dislocation at the follow-up examination, referral should be made at that time. If the examination findings are still equivocal, the infant can undergo ultrasonography of the hips or be reexamined every few weeks through the first six weeks of life. Although equivocal findings commonly resolve spontaneously, infants with persistent equivocal findings of developmental dysplasia of the hip longer than six weeks should be evaluated by an orthopedist. Treatment generally involves flexion-abduction splinting. The benefits of treatment are unclear, and there are risks to treatment, most notably an increased occurrence of avascular necrosis of the femoral head. PMID:25591184

  9. Acute traumatic patellar dislocation.

    PubMed

    Duthon, V B

    2015-02-01

    Inaugural traumatic patellar dislocation is most often due to trauma sustained during physical or sports activity. Two-thirds of acute patellar dislocations occur in young active patients (less than 20 years old). Non-contact knee sprain in flexion and valgus is the leading mechanism in patellar dislocation, accounting for as many as 93% of all cases. The strong displacement of the patella tears the medial stabilizing structures, and notably the medial patellofemoral ligament (MPFL), which is almost always injured in acute patellar dislocation, most frequently at its femoral attachment. Lateral patellar glide can be assessed with the knee in extension or 20° flexion. Displacement by more than 50% of the patellar width is considered abnormal and may induce apprehension. Plain X-ray and CT are mandatory to diagnose bony risk factors for patellar dislocation, such as trochlear dysplasia or increased tibial tubercle-trochlear groove distance (TT-TG), and plan correction. MRI gives information on cartilage and capsulo-ligamentous status for treatment planning: free bodies or osteochondral fracture have to be treated surgically. If patellar dislocation occurs in an anatomically normal knee and osteochondral fracture is ruled out on MRI, non-operative treatment is usually recommended. PMID:25592052

  10. Constrained captive acetabular cup for recurrent dislocation of hemiarthroplasty in elderly: A case series

    PubMed Central

    Rajeev, Aysha; Banaszkiewicz, Paul

    2016-01-01

    Introduction Hemiarthroplasty of the hip is one of the commonest procedures done for intracapsular fractures of the neck of femur in elderly. Dislocation of the hemiarthroplasty is a recognised and significant complication. This is associated with considerable morbidity and mortality. The treatment options include closed manipulation, skin and skeletal traction, conversion to total hip replacement, exploration and open reduction and leaving it out of the acetabulum. Presentation of case A retrospective review of ten patients with recurrent and failed closed manipulative reduction of hemiarthroplasty who underwent revision using a cemented captive acetabular cup and cement to cement revision of femoral component with Exeter CDH stem was carried out. The follow up period was two years and the functional outcomes were assessed using Harris hip scores. Discussion The management of recurrent dislocations of hemiarthroplasty in elderly patient are very challenging. Even though various treatment options are described most of them are associated with increased morbidity and mortality and prevent these patients from early mobilisation. The use of captive acetabular avoid repeated dislocations, prolonged bed rest, wearing of a brace and all the complications associated with sustained immobilization. The drawbacks of using constrained cups are hip pain, limited hip movements and loosening. Conclusion We describe a new method of treatment of this difficult condition with a cemented constrained acetabular captive cup and cement to cement revision using a CDH femoral stem. This method prevents further dislocations and will give good functional outcomes thus reducing the high morbidity and mortality. PMID:27129135

  11. Is There a Benefit to Head Size Greater Than 36 mm in Total Hip Arthroplasty?

    PubMed

    Haughom, Bryan D; Plummer, Darren R; Moric, Mario; Della Valle, Craig J

    2016-01-01

    This study compares the rate of dislocation and revision for instability between 36-mm and anatomic femoral heads (large diameter metal-on-metal THA, dual-mobility bearings, and hip resurfacing arthroplasty) in patients at high risk for dislocation. A total of 501 high-risk patients, over a 10-year period, were identified (282 36-mm THA, 24 dual-mobility bearings, 83 metal-on-metal arthroplasty, and 112 hip resurfacing arthroplasty). There were 13 dislocations in the 36-mm group compared to 1 in the anatomic group (4.6% vs 0.5%; P = .005). Four patients dislocated more than once in the 36-mm group (1.4% vs 0%; P = .04), and 2 patients in the 36-mm group required a revision for instability (0.7% vs 0%; P = .11). These results suggest that anatomic head sizes significantly lower the risk of dislocation in high-risk patients. PMID:26360768

  12. Statistical characterization of dislocation ensembles

    SciTech Connect

    El-Azab, A; Deng, J; Tang, M

    2006-05-17

    We outline a method to study the spatial and orientation statistics of dynamical dislocation systems by modeling the dislocations as a stochastic fiber process. Statistical measures have been introduced for the density, velocity, and flux of dislocations, and the connection between these measures and the dislocation state and plastic distortion rate in the crystal is explained. A dislocation dynamics simulation model has been used to extract numerical data to study the evolution of these statistical measures numerically in a body-centered cubic crystal under deformation. The orientation distribution of the dislocation density, velocity and dislocation flux, as well as the dislocation correlations have been computed. The importance of the statistical measures introduced here in building continuum models of dislocation systems is highlighted.

  13. Preventing Leg Length Discrepancy and Instability After Total Hip Arthroplasty.

    PubMed

    Sculco, Peter K; Austin, Matthew S; Lavernia, Carlos J; Rosenberg, Aaron G; Sierra, Rafael J

    2016-01-01

    Restoration of equal leg lengths and dynamic hip stability are essential elements of a successful total hip arthroplasty. A careful clinical examination, a preoperative plan, and appropriate intraoperative techniques are necessary to achieve these goals. Preoperative identification of patients at risk for residual leg length discrepancy allows surgeons to adjust the surgical approach and/or the type of implant and provide better preoperative patient education. The use of larger femoral heads, high-offset stem options, and enhanced soft-tissue repairs have improved impingement-free range of motion as well as dynamic hip stability and have contributed to an overall reduction in dislocation. Methods for accurate leg length restoration and component positioning include anatomic landmarks, intraoperative radiographs, intraoperative calipers, stability testing, and computer-assisted surgery. If recurrent instability occurs after total hip arthroplasty, the underlying cause for dislocation should be identified and treated; this may include the use of semiconstrained dual-mobility or fully constrained liners, depending on abductor function. Surgeons should be aware of the clinical and surgical techniques for achieving leg length equalization and dynamic hip stability in total hip arthroplasty. PMID:27049193

  14. Impingement in Total Hip Replacement: Mechanisms and Consequences

    PubMed Central

    Brown, Thomas D.; Callaghan, John J.

    2009-01-01

    The occurrence of total hip impingement, whether or not accompanied by frank dislocation, holds substantial untoward clinical consequences, especially as less-forgiving advanced bearing implant designs come into ever more widespread use. Biomechanical aspects of impingement and dislocation have historically received relatively little scientific attention, although that situation is now rapidly changing. The present article reviews contemporary laboratory and clinical research on the impingement/dislocation phenomena, focusing particularly on how implant design variables, surgical implantation factors and patient activity each act individually and in concert to pose impingement and dislocation challenges. In recent years, several powerful new research methodologies have emerged that have greatly expanded the scope for clinical translation of systematic laboratory study. Transferring the findings from such research into yet better implant designs, and even better surgical procedures, offers encouragement that the clinical impact of this troublesome complication can be further reduced. PMID:19956356

  15. Supersonic Dislocation Bursts in Silicon

    DOE PAGESBeta

    Hahn, E. N.; Zhao, S.; Bringa, E. M.; Meyers, M. A.

    2016-06-06

    Dislocations are the primary agents of permanent deformation in crystalline solids. Since the theoretical prediction of supersonic dislocations over half a century ago, there is a dearth of experimental evidence supporting their existence. Here we use non-equilibrium molecular dynamics simulations of shocked silicon to reveal transient supersonic partial dislocation motion at approximately 15 km/s, faster than any previous in-silico observation. Homogeneous dislocation nucleation occurs near the shock front and supersonic dislocation motion lasts just fractions of picoseconds before the dislocations catch the shock front and decelerate back to the elastic wave speed. Applying a modified analytical equation for dislocation evolutionmore » we successfully predict a dislocation density of 1.5 x 10(12) cm(-2) within the shocked volume, in agreement with the present simulations and realistic in regards to prior and on-going recovery experiments in silicon.« less

  16. Supersonic Dislocation Bursts in Silicon.

    PubMed

    Hahn, E N; Zhao, S; Bringa, E M; Meyers, M A

    2016-01-01

    Dislocations are the primary agents of permanent deformation in crystalline solids. Since the theoretical prediction of supersonic dislocations over half a century ago, there is a dearth of experimental evidence supporting their existence. Here we use non-equilibrium molecular dynamics simulations of shocked silicon to reveal transient supersonic partial dislocation motion at approximately 15 km/s, faster than any previous in-silico observation. Homogeneous dislocation nucleation occurs near the shock front and supersonic dislocation motion lasts just fractions of picoseconds before the dislocations catch the shock front and decelerate back to the elastic wave speed. Applying a modified analytical equation for dislocation evolution we successfully predict a dislocation density of 1.5 × 10(12) cm(-2) within the shocked volume, in agreement with the present simulations and realistic in regards to prior and on-going recovery experiments in silicon. PMID:27264746

  17. Supersonic Dislocation Bursts in Silicon

    PubMed Central

    Hahn, E. N.; Zhao, S.; Bringa, E. M.; Meyers, M. A.

    2016-01-01

    Dislocations are the primary agents of permanent deformation in crystalline solids. Since the theoretical prediction of supersonic dislocations over half a century ago, there is a dearth of experimental evidence supporting their existence. Here we use non-equilibrium molecular dynamics simulations of shocked silicon to reveal transient supersonic partial dislocation motion at approximately 15 km/s, faster than any previous in-silico observation. Homogeneous dislocation nucleation occurs near the shock front and supersonic dislocation motion lasts just fractions of picoseconds before the dislocations catch the shock front and decelerate back to the elastic wave speed. Applying a modified analytical equation for dislocation evolution we successfully predict a dislocation density of 1.5 × 1012 cm−2 within the shocked volume, in agreement with the present simulations and realistic in regards to prior and on-going recovery experiments in silicon. PMID:27264746

  18. Supersonic Dislocation Bursts in Silicon

    NASA Astrophysics Data System (ADS)

    Hahn, E. N.; Zhao, S.; Bringa, E. M.; Meyers, M. A.

    2016-06-01

    Dislocations are the primary agents of permanent deformation in crystalline solids. Since the theoretical prediction of supersonic dislocations over half a century ago, there is a dearth of experimental evidence supporting their existence. Here we use non-equilibrium molecular dynamics simulations of shocked silicon to reveal transient supersonic partial dislocation motion at approximately 15 km/s, faster than any previous in-silico observation. Homogeneous dislocation nucleation occurs near the shock front and supersonic dislocation motion lasts just fractions of picoseconds before the dislocations catch the shock front and decelerate back to the elastic wave speed. Applying a modified analytical equation for dislocation evolution we successfully predict a dislocation density of 1.5 × 1012 cm‑2 within the shocked volume, in agreement with the present simulations and realistic in regards to prior and on-going recovery experiments in silicon.

  19. Dislocation dynamics in confined geometry

    NASA Astrophysics Data System (ADS)

    Gómez-García, D.; Devincre, B.; Kubin, L.

    1999-05-01

    A simulation of dislocation dynamics has been used to calculate the critical stress for a threading dislocation moving in a confined geometry. The optimum conditions for conducting simulations in systems of various sizes, down to the nanometer range, are defined. The results are critically compared with the available theoretical and numerical estimates for the problem of dislocation motion in capped layers.

  20. Behavior of dislocations in silicon

    SciTech Connect

    Sumino, Koji

    1995-08-01

    A review is given of dynamic behavior of dislocations in silicon on the basis of works of the author`s group. Topics taken up are generation, motion and multiplication of dislocations as affected by oxygen impurities and immobilization of dislocations due to impurity reaction.

  1. Dislocated Worker Project.

    ERIC Educational Resources Information Center

    1988

    Due to the severe economic decline in the automobile manufacturing industry in southeastern Michigan, a Dislocated Workers Program has been developed through the partnership of the Flint Area Chamber of Commerce, three community colleges, the National Center for Research in Vocational Education, the Michigan State Department of Education, the…

  2. On the permanent hip-stabilizing effect of atmospheric pressure.

    PubMed

    Prietzel, Torsten; Hammer, Niels; Schleifenbaum, Stefan; Kaßebaum, Eric; Farag, Mohamed; von Salis-Soglio, Georg

    2014-08-22

    Hip joint dislocations related to total hip arthroplasty (THA) are a common complication especially in the early postoperative course. The surgical approach, the alignment of the prosthetic components, the range of motion and the muscle tone are known factors influencing the risk of dislocation. A further factor that is discussed until today is atmospheric pressure which is not taken into account in the present THA concepts. The aim of this study was to investigate the impact of atmospheric pressure on hip joint stability. Five joint models (Ø 28-44 mm), consisting of THA components were hermetically sealed with a rubber capsule, filled with a defined amount of fluid and exposed to varying ambient pressure. Displacement and pressure sensors were used to record the extent of dislocation related to intraarticular and ambient pressure. In 200 experiments spontaneous dislocations of the different sized joint models were reliably observed once the ambient pressure was lower than 6.0 kPa. Increasing the ambient pressure above 6.0 kPa immediately and persistently reduced the joint models until the ambient pressure was lowered again. Displacement always exceeded half the diameter of the joint model and was independent of gravity effects. This experimental study gives strong evidence that the hip joint is permanently stabilized by atmospheric pressure, confirming the theories of Weber and Weber (1836). On basis of these findings the use of larger prosthetic heads, capsular repair and the deployment of an intracapsular Redon drain are proposed to substantially decrease the risk of dislocation after THA. PMID:24938930

  3. Hip joint replacement - slideshow

    MedlinePlus

    ... this page: //medlineplus.gov/ency/presentations/100006.htm Hip joint replacement - series—Normal anatomy To use the sharing ... to slide 5 out of 5 Overview The hip joint is made up of two major parts: the ...

  4. Hip joint injection

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/007633.htm Hip joint injection To use the sharing features on this ... injection is a shot of medicine into the hip joint. The medicine helps relieve pain and inflammation. It ...

  5. Hip joint replacement

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/002975.htm Hip joint replacement To use the sharing features on this page, please enable JavaScript. Hip joint replacement is surgery to replace all or part ...

  6. Hip fracture surgery

    MedlinePlus

    ... neck fracture repair; Trochanteric fracture repair; Hip pinning surgery; Osteoarthritis-hip ... You may receive general anesthesia before this surgery. This means ... spinal anesthesia. With this kind of anesthesia, medicine is ...

  7. Bursitis of the Hip

    MedlinePlus

    ... following: Repeated overuse or stress of the hip Rheumatoid arthritis Gout Pseudogout Injury of the hip Infection with bacteria, such as Staphylococcus aureus (or a staph infection) Diabetes Spine problems, such as scoliosis Uneven leg lengths ...

  8. Discrepancies in ultrasonography of the infant hip.

    PubMed

    Joseph, K N; Meyer, S

    1996-01-01

    A total of 4,984 ultrasonographic (US) examinations of infant hips were done for the diagnosis or management of congenital/developmental dislocation/ dysplasia of the hip; 48 instances of lack of correlation (0.96%) between the US and radiographic images were noted. Analysis of these cases permitted classification into two groups: (a) apparent discrepancy (44 cases, 0.88%) for which faulty technique or interpretation of the sonogram/radiograph, hyperlaxity, inadvertent stress views, and lateral ossification defects led to disparity in the imaging modalities; and (b) true discrepancy (4 cases, 0.08%) where no explanation was possible for the dissimilarity. The relevance of this study is that the majority of discrepancies can be eliminated by (a) avoiding the common causes of apparent discrepancies mentioned in this article and by (b) the use of the Graf and Harcke techniques as complementary methods of US examination. PMID:8897261

  9. Advanced wear of an Oxinium™ femoral head implant following polyethylene liner dislocation.

    PubMed

    Tribe, H; Malek, S; Stammers, J; Ranawat, V; Skinner, J A

    2013-11-01

    Oxinium™ (Smith & Nephew, Memphis, TN, US) has been used in hip arthroplasty since 2003. The surface coating is hard and provides low wear rates but if this surface coating is damaged, the soft metal core is at risk of accelerated wear. Previous reports have described accelerated wear following intra and postoperative hip dislocation. We report a case of advanced wear of an in situ Oxinium™ femoral head implant following a cracked acetabular liner. The liner had disengaged from the titanium shell, allowing the Oxinium™ head to articulate directly with the shell. The disengaged liner led to dislocation of the Oxinium™ head, with associated pronounced wear of the head and the acetabular cup. The patient had a successful revision procedure. We advise close follow-up of patients with Oxinium™ implants, especially if associated with dislocation and closed reduction. PMID:24165329

  10. Technical Note on Modified Posterior Approach to the Hip Joint

    PubMed Central

    Iyer, Krishna Mohan

    2015-01-01

    Introduction: The posterior approach is the most commonly and relatively easy to be used to expose the hip joint. Posterior approaches allow excellent visualization of the entire acetabulum and the upper femoral shaft, and thus they are popular for revision joint replacement surgery particularly in cases where only the femoral component needs to be replaced. There may be a higher dislocation rate with minimal movement as compared to anterior approaches if the posterior approach is used in fractured neck of femur surgery in demented or elderly bedridden patients who often lie crouched in bed with their hips in a flexed and adducted position. The expected purpose of this modification of the Posterior Approach to the Hip Joint is to overcome the fear of dislocation and hence combine the advantages of the Posterior route with greater stability. Technique: The author’s original paper written 30 years ago (Iyer, 1981) presented an original technique devised to confer greater stability to the hip joint posteriorly to minimize the greater incidence of dislocation which has been reported extensively in literature. The technique involves an osteotomy of the posterior overhanging part of the greater trochanter to include the insertions of the short lateral rotators along with the posterior third of the gluteus medius, which can then be turned back in one piece like the page of a book to include the capsule of the hip joint. This gives wide exposure of the posterior lip of the acetabulum and is relatively bloodless in its exposure. This approach is very useful in the elderly particularly demented patients requiring a hemiarthroplasty and also in primary and revision total hip replacement. This approach has been tested in cadavers to conclude the greater stability given as compared to the routine resuture or reattachment of the short lateral rotators. Conclusion: The modified technique provides for greater stability as compared to the Southern Approach. PMID:27299026

  11. Hip Arthroplasty in Obese Patients: Rising Prevalence–Standard Procedures?

    PubMed Central

    Skutek, Michael; Wirries, Nils; von Lewinski, Gabriela

    2016-01-01

    We examined our experience and, in particular, complications associated with total hip arthroplasty in obese and morbidly obese patients. We prospectively gathered 50 patients in a matched control series including 25 obese and morbidly obese patients. All patients were operated using the direct lateral approach and standard postoperative protocols. Operating room time, complications, dislocations, blood loss, cup position and clinical parameters using the Harris Hip Score and the Western Ontario and McMaster Universities Arthritis Index results were compared. Although there were some significant differences in clinical outcomes, standard procedures yielded good overall results and an acceptable rate of complications. Details approaching this patient entity are being discussed. PMID:27433302

  12. Hip Arthroplasty in Obese Patients: Rising Prevalence-Standard Procedures?

    PubMed

    Skutek, Michael; Wirries, Nils; von Lewinski, Gabriela

    2016-06-27

    We examined our experience and, in particular, complications associated with total hip arthroplasty in obese and morbidly obese patients. We prospectively gathered 50 patients in a matched control series including 25 obese and morbidly obese patients. All patients were operated using the direct lateral approach and standard postoperative protocols. Operating room time, complications, dislocations, blood loss, cup position and clinical parameters using the Harris Hip Score and the Western Ontario and McMaster Universities Arthritis Index results were compared. Although there were some significant differences in clinical outcomes, standard procedures yielded good overall results and an acceptable rate of complications. Details approaching this patient entity are being discussed. PMID:27433302

  13. [An unusual early complication in cementless replacement of the hip joint. Case report].

    PubMed

    Kauschke, T; Zilch, H

    1994-12-01

    This is the first description of a dislocation of the polyethyleninlay from the cup of a cementless hip prosthesis. Due to a fall of the patient 8 months after the implantation an unspecific complaint arised. In spite of detailed diagnostic no reason could have been found. During the renewed operation we saw the dislocated inlay by mechanical anchorage of the cup and the shaft. Retrospective there were made suggestions how the described complication could be recognized earlier. PMID:7871611

  14. Elastodynamic image forces on dislocations

    PubMed Central

    Gurrutxaga-Lerma, Beñat; Balint, Daniel S.; Dini, Daniele; Sutton, Adrian P.

    2015-01-01

    The elastodynamic image forces on edge and screw dislocations in the presence of a planar-free surface are derived. The explicit form of the elastodynamic fields of an injected, quiescent screw dislocation are also derived. The resulting image forces are affected by retardation effects: the dislocations experience no image force for a period of time defined by the arrival and reflection at the free surface of the dislocation fields. For the case of injected, stationary dislocations, it is shown that the elastodynamic image force tends asymptotically to the elastotatic prediction. For the case of injected, moving dislocations, it is shown that the elastodynamic image force on both the edge and the screw dislocations is magnified by inertial effects, and becomes increasingly divergent with time; this additional effect, missing in the elastostatic description, is shown to be substantial even for slow moving dislocations. Finally, it is shown that the elastodynamic image force of an edge dislocation moving towards the surface at the Rayleigh wave speed becomes repulsive, rather than attractive; this is suggestive of instabilities at the core of the dislocation, and likely resonances with the free surface. PMID:26528080

  15. Thermodynamically consistent continuum dislocation dynamics

    NASA Astrophysics Data System (ADS)

    Hochrainer, Thomas

    2016-03-01

    Dislocation based modeling of plasticity is one of the central challenges at the crossover of materials science and continuum mechanics. Developing a continuum theory of dislocations requires the solution of two long standing problems: (i) to represent dislocation kinematics in terms of a reasonable number of variables and (ii) to derive averaged descriptions of the dislocation dynamics (i.e. material laws) in terms of these variables. The kinematic problem (i) was recently solved through the introduction of continuum dislocation dynamics (CDD), which provides kinematically consistent evolution equations of dislocation alignment tensors, presuming a given average dislocation velocity (Hochrainer, T., 2015, Multipole expansion of continuum dislocations dynamics in terms of alignment tensors. Philos. Mag. 95 (12), 1321-1367). In the current paper we demonstrate how a free energy formulation may be used to solve the dynamic closure problem (ii) in CDD. We do so exemplarily for the lowest order CDD variant for curved dislocations in a single slip situation. In this case, a thermodynamically consistent average dislocation velocity is found to comprise five mesoscopic shear stress contributions. For a postulated free energy expression we identify among these stress contributions a back-stress term and a line-tension term, both of which have already been postulated for CDD. A new stress contribution occurs which is missing in earlier CDD models including the statistical continuum theory of straight parallel edge dislocations (Groma, I., Csikor, F.F., Zaiser, M., 2003. Spatial correlations and higher-order gradient terms in a continuum description of dislocation dynamics. Acta Mater. 51, 1271-1281). Furthermore, two entirely new stress contributions arise from the curvature of dislocations.

  16. Disparity between Clinical and Ultrasound Examinations in Neonatal Hip Screening

    PubMed Central

    Kyung, Bong Soo; Jeong, Woong Kyo; Park, Si Young

    2016-01-01

    Background For early detection of developmental dysplasia of the hip (DDH), neonatal hip screening using clinical examination and/or ultrasound has been recommended. Although there have been many studies on the reliability of both screening techniques, there is still controversy in the screening strategies; clinical vs. selective or universal ultrasound screening. To determine the screening strategy, we assessed the agreement among the methods; clinical examination by an experienced pediatric orthopedic surgeon, sonographic morphology, and sonographic stability. Methods From January 2004 to June 2009, a single experienced pediatric orthopedic surgeon performed clinical hip screenings for 2,686 infants in the neonatal unit and 43 infants who were referred due to impressions of hip dysplasia before 3 months of age. Among them, 156 clinically unstable or high-risk babies selectively received bilateral hip ultrasound examinations performed by the same surgeon using the modified Graf method. The results were analyzed statistically to detect any correlations between the clinical and sonographic findings. Results Although a single experienced orthopedic surgeon conducted all examinations, we detected only a limited relationship between the results of clinical and ultrasound examinations. Ninety-three percent of the clinically subluxatable hips were normal or immature based on static ultrasound examination, and 74% of dislocating hips and 67% of limited abduction hips presented with the morphology below Graf IIa. A total of 80% of clinically subluxatable, 42% of dislocating and 67% of limited abduction hips appeared stable or exhibited minor instability on dynamic ultrasound examination. About 7% of clinically normal hips were abnormal upon ultrasound examination; 5% showed major instability and 3% showed dysplasia above Graf IIc. Clinical stability had small coefficients between ultrasound examinations; 0.39 for sonographic stability and 0.37 for sonographic morphology

  17. Design rules for dislocation filters

    SciTech Connect

    Ward, T.; Sánchez, A. M.; Beanland, R.; Tang, M.; Wu, J.; Liu, H.; Dunstan, D. J.

    2014-08-14

    The efficacy of strained layer threading dislocation filter structures in single crystal epitaxial layers is evaluated using numerical modeling for (001) face-centred cubic materials, such as GaAs or Si{sub 1−x}Ge{sub x}, and (0001) hexagonal materials such as GaN. We find that threading dislocation densities decay exponentially as a function of the strain relieved, irrespective of the fraction of threading dislocations that are mobile. Reactions between threading dislocations tend to produce a population that is a balanced mixture of mobile and sessile in (001) cubic materials. In contrast, mobile threading dislocations tend to be lost very rapidly in (0001) GaN, often with little or no reduction in the immobile dislocation density. The capture radius for threading dislocation interactions is estimated to be approximately 40 nm using cross section transmission electron microscopy of dislocation filtering structures in GaAs monolithically grown on Si. We find that the minimum threading dislocation density that can be obtained in any given structure is likely to be limited by kinetic effects to approximately 10{sup 4}–10{sup 5 }cm{sup −2}.

  18. Dislocation dynamics in nanocrystalline nickel.

    PubMed

    Shan, Z W; Wiezorek, J M K; Stach, E A; Follstaedt, D M; Knapp, J A; Mao, S X

    2007-03-01

    It is believed that the dynamics of dislocation processes during the deformation of nanocrystalline materials can only be visualized by computational simulations. Here we demonstrate that observations of dislocation processes during the deformation of nanocrystalline Ni with grain sizes as small as 10 nm can be achieved by using a combination of in situ tensile straining and high-resolution transmission electron microscopy. Trapped unit lattice dislocations are observed in strained grains as small as 5 nm, but subsequent relaxation leads to dislocation recombination. PMID:17359167

  19. Dynamic transitions in dislocation motion

    NASA Astrophysics Data System (ADS)

    Bulatov, Vasily; Cai, Wei; Marian, Jaime

    2003-03-01

    In a series of Molecular Dynamics simulations, we observe that, depending on stress, temperature and line length, screw dislocations in BCC iron move in three strikingly different regimes. Under low stress, the dislocations move smoothly via formation and migration of atomic-sized kinks; although widely believed, such motion mechanism has never been directly observed in full dynamic detail. Then, at a higher stress, dislocation motion suddenly becomes rough: the line becomes rugged and its motion becomes jerky producing in its wake a large amount of debris in the form of lattice vacancies and interstitial clusters. Remarkably, this bizarre behavior is not caused by any external factors, such as dislocation interaction with other crystal defects: the roughening transition is intrinsic to the dislocation itself. Under increasing stress the line raggedness and the amount of debris its motion produces continue to increase until, at some point, another dynamic transition takes place. The dislocation is now seen to cease at once its turbulent motion through the lattice and to initiate a thin plate of sheared crystal, a twin. The twin plate picks up where the dislocation just left off - it extends very fast in the same direction as dislocation motion and increases, gradually, in thickness. Notably, no more debris is produced during the twinning motion. The origin of these dynamic transitions, the underlying atomistic mechanisms of dislocation motion in all three regimes and their implication for strength of shocked materials are discussed.

  20. Multiligamentous injuries and knee dislocations.

    PubMed

    Gimber, Lana H; Scalcione, Luke R; Rowan, Andrew; Hardy, Jolene C; Melville, David M; Taljanovic, Mihra S

    2015-11-01

    Complex capsular ligamentous structures contribute to stability of the knee joint. Simultaneous injury of two or more knee ligaments, aside from concurrent tears involving the anterior cruciate and medial collateral ligaments, is considered to be associated with femorotibial knee dislocations. Proximal tibiofibular joint dislocations are not always easily recognized and may be overlooked or missed. Patellofemoral dislocations can be transient with MR imaging sometimes required to reach the diagnosis. In this article, the authors describe the mechanism of injury, ligamentous disruptions, imaging, and treatment options of various types of knee dislocations including injuries of the femorotibial, proximal tibiofibular, and patellofemoral joints. PMID:26002747

  1. Smectic Edge Dislocations under Shear

    NASA Astrophysics Data System (ADS)

    Chen, Peilong; Lu, Chun-Yi David

    2011-09-01

    Layer structures around an edge dislocation in a smectic phase under shear are studied with both phase field and order parameter models. It is shown that, contrast to a crystal solid, the conventional picture of the Peach--Koehler force experienced by dislocations when the sample is under a shear stress cannot be readily applied to the smectic phases. Under a uniform shear flow, we obtain the phase field and order parameter solutions around an edge dislocation. The solutions elucidate properties such as the layer distortion range around the dislocation and scaling of inter-dislocation interaction on dislocation separation. Calculations on energy dissipation indicate the extreme shear-thinning behavior that an edge dislocation induces a shear stress independent of the shear rate. Finally in a bulk sample with dislocation forming loops and networks, we argue that the uniform flow component around the dislocation is important to the energy dissipation and we show that its scaling exponent with the shear rate is very close to results from many previous rheology measurements.

  2. Atlanto-occipital dislocation

    PubMed Central

    Hall, Graham C; Kinsman, Michael J; Nazar, Ryan G; Hruska, Rob T; Mansfield, Kevin J; Boakye, Maxwell; Rahme, Ralph

    2015-01-01

    Atlanto-occipital dislocation (AOD) is being increasingly recognized as a potentially survivable injury as a result of improved prehospital management of polytrauma patients and increased awareness of this entity, leading to earlier diagnosis and more aggressive treatment. However, despite overall improved outcomes, AOD is still associated with significant morbidity and mortality. The purpose of this paper is to review the biomechanical aspects, clinical features, radiologic criteria, and treatment strategies of AOD. Given that the diagnosis of AOD can be very challenging, a high degree of clinical suspicion is essential to ensure timely recognition and treatment, thus preventing neurological decline or death. PMID:25793163

  3. Hip resurfacing: history, current status, and future.

    PubMed

    Amstutz, Harlan C; Le Duff, Michel J

    2015-01-01

    Hip resurfacing arthroplasty (HRA) presents several advantages over conventional total hip arthroplasty (THA), including conservation and preservation of bone, reduced risk of dislocation, easy replication of hip biomechanics and easy revision if needed. It is a particularly appealing procedure for young patients. HRA has been performed for over 40 years following the same technological advances as THA. The bearing material used by most designs is metal-on-metal (MoM), which has the best compromise between strength and wear properties. However, MoM HRA has a specific set of possible complications. Aseptic femoral failures were initially the most prevalent cause for revision but progress in patient selection and surgical technique seem to have resolved this problem. Wear-related failures (high metal ion levels and adverse local tissue reactions) are now the main concern, and are essentially associated with poor acetabular component design and orientation, to which MoM is more sensitive than other bearing materials. The concept of functional coverage is key to understanding how MoM bearings are affected by edge wear. Only a 3-D assessment of cup position (e.g., the contact patch to rim distance) provides the necessary information to determine the role of cup positioning in relationship with abnormal bearing wear.The concept of hip resurfacing is more valid today than ever as the age of the patients in need of hip arthroplasty keeps getting lower. The recent publication of several excellent long-term survivorship results suggests that selection of a well-designed resurfacing system and accuracy in the placement of the cup can achieve long-term durability. PMID:26109156

  4. Hip fracture - discharge

    MedlinePlus

    Inter-trochanteric fracture repair - discharge; Subtrochanteric fracture repair - discharge; Femoral neck fracture repair - discharge; Trochanteric fracture repair - discharge; Hip pinning surgery - discharge

  5. Transient Synovitis of the Hip

    MedlinePlus

    ... inflammation and swelling of the tissues around the hip joint. Usually only one hip is affected. This condition ... to reduce the swelling and inflammation around the hip joint. Your child's doctor will probably ask you to ...

  6. Current Concepts for Patellar Dislocation

    PubMed Central

    Petri, Maximilian; Ettinger, Max; Stuebig, Timo; Brand, Stephan; Krettek, Christian; Jagodzinski, Michael; Omar, Mohamed

    2015-01-01

    Context: Patellar dislocation usually occurs to the lateral side, leading to ruptures of the Medial Patellofemoral Ligament (MPFL) in about 90% of the cases. Even though several prognostic factors are identified for patellofemoral instability after patellar dislocation so far, the appropriate therapy remains a controversial issue. Evidence Acquisition: Authors searched the Medline library for studies on both surgical and conservative treatment for patellar dislocation and patellofemoral instability. Additionally, the reference list of each article was searched for additional studies. Results: A thorough analysis of the anatomical risk factors with a particular focus on patella alta, increased Tibial Tuberosity-Trochlear Groove (TT-TG) distance, trochlear dysplasia as well as torsional abnormalities should be performed early after the first dislocation to allow adequate patient counseling. Summarizing the results of all published randomized clinical trials and comparing surgical and conservative treatment after the first-time patellar dislocation until today indicated no significant evident difference for children, adolescents, and adults. Therefore, nonoperative treatment was indicated after a first-time patellar dislocation in the vast majority of patients. Conclusions: Surgical treatment for patellar dislocation is indicated primarily in case of relevant concomitant injuries such as osteochondral fractures, and secondarily for recurrent dislocations. PMID:26566512

  7. Turned head--adducted hip--truncal curvature syndrome.

    PubMed Central

    Hamanishi, C; Tanaka, S

    1994-01-01

    One hundred and eight neonates and infants who showed the clinical triad of a head turned to one side, adduction contracture of the hip joint on the occipital side of the turned head, and truncal curvature, which we named TAC syndrome, were studied. These cases included seven with congenital and five with late infantile dislocations of the hip joint and 14 who developed muscular torticollis. Forty one were among 7103 neonates examined by one of the authors. An epidemiological analysis confirmed the aetiology of the syndrome to be environmental. The side to which the head was turned and that of the adducted hip contracture showed a high correlation with the side of the maternal spine on which the fetus had been lying. TAC syndrome is an important asymmetrical deformity that should be kept in mind during neonatal examination, and may be aetiologically related to the unilateral dislocation of the hip joint, torticollis, and infantile scoliosis which develop after a vertex presentation. Images PMID:8048823

  8. Bilateral total hip replacement in arthrogryposis multiplex congenita.

    PubMed

    Dalton, David Michael; Magill, Paul; Mulhall, Kevin James

    2015-01-01

    The authors present a case of bilateral total hip replacements (THRs) in a 56-year-old patient with arthrogryposis multiplex congenita (AMC). The considerations for the perioperative period and the outcome are discussed. Preoperative planning included an anaesthetic review and availability of fiberoptic intubation due to poor mouth opening. Perioperatively, contractures can make positioning and exposure difficult but in this case a standard posterior approach was taken. Particular attention was given to soft tissue balancing given the theoretical risk of dislocation. There were no perioperative complications. Postoperatively there has been improvement in pain and hip scores but the patient has failed to return to work. Objective improvements in range of motion (ROM) have not been made. This experience suggests THR is a safe and effective treatment for osteoarthritic hip pain in patients with AMC but patients should be informed that ROM is unlikely to improve. PMID:26607193

  9. Dislocation Mechanics Under Extreme Pressures

    NASA Astrophysics Data System (ADS)

    Armstrong, Ronald; Arnold, Werner; Zerilli, Frank

    2007-06-01

    The shock-induced plasticity of copper, Armco iron, and tantalum materials is attributed to strain rate control by a substantial dislocation density being generated at the shock front. A thermal activation type constitutive equation is employed for the dislocation generation based on achievement of a limiting small activation volume for the process. A linear dependence of the equivalent compressive stress on logarithm of the plastic strain rate is predicted. The prediction compares favorably with Swegle-Grady and Meyers measurements previously fitted to a power law relationship. For Armco iron and tantalum, control is matched with a dislocation description of deformation twinning at the shock front. By comparison, the uniform shock-less loading in an isentropic compression experiment (ICE) provides for plastic strain rate control by the drag-resisted movement of mobile dislocations within the resident dislocation density.

  10. Acetabular Reconstruction in Total Hip Arthroplasty

    PubMed Central

    Santhanam, Siva Swaminathan; Choi, Jung Woo

    2016-01-01

    The difficulties encountered in dealing with the bone deficient acetabulum are amongst the greatest challenges in hip surgery. Acetabular reconstruction in revision total hip arthroplasty can successfully be achieved with hemispherical components featuring a porous or roughened ingrowth surface and options for placement of multiple screws for minor acetabular defect. Acetabular component selection is mostly based on the amount of bone loss present. In the presence of combined cavitary and segmental defects without superior acetabular coverage, reconstructions with a structural acetabular allograft protected by a cage or a custom-made triflange cage have been one of preferred surgical options. The use of a cage or ring over structural allograft bone for massive uncontained defects in acetabular revision can restore host bone stock and facilitate subsequent rerevision surgery to a certain extent. But high complication rates have been reported including aseptic loosening, infection, dislocation and metal failure. On the other hand, recent literature is reporting satisfactory outcomes with the use of modular augments combined with a hemispherical shell for major acetabular defect. Highly porous metals have been introduced for clinical use in arthroplasty surgery over the last decade. Their higher porosity and surface friction are ideal for acetabular revision, optimizing biological fixation. The use of trabecular metal cups in acetabular revision has yielded excellent clinical results. This article summarizes author's experience regarding revision acetabular reconstruction options following failed hip surgery including arthroplasty. PMID:27536638

  11. Acetabular Reconstruction in Total Hip Arthroplasty.

    PubMed

    Shon, Won Yong; Santhanam, Siva Swaminathan; Choi, Jung Woo

    2016-03-01

    The difficulties encountered in dealing with the bone deficient acetabulum are amongst the greatest challenges in hip surgery. Acetabular reconstruction in revision total hip arthroplasty can successfully be achieved with hemispherical components featuring a porous or roughened ingrowth surface and options for placement of multiple screws for minor acetabular defect. Acetabular component selection is mostly based on the amount of bone loss present. In the presence of combined cavitary and segmental defects without superior acetabular coverage, reconstructions with a structural acetabular allograft protected by a cage or a custom-made triflange cage have been one of preferred surgical options. The use of a cage or ring over structural allograft bone for massive uncontained defects in acetabular revision can restore host bone stock and facilitate subsequent rerevision surgery to a certain extent. But high complication rates have been reported including aseptic loosening, infection, dislocation and metal failure. On the other hand, recent literature is reporting satisfactory outcomes with the use of modular augments combined with a hemispherical shell for major acetabular defect. Highly porous metals have been introduced for clinical use in arthroplasty surgery over the last decade. Their higher porosity and surface friction are ideal for acetabular revision, optimizing biological fixation. The use of trabecular metal cups in acetabular revision has yielded excellent clinical results. This article summarizes author's experience regarding revision acetabular reconstruction options following failed hip surgery including arthroplasty. PMID:27536638

  12. The evolution and concepts of joint-preserving surgery of the hip.

    PubMed

    Leunig, M; Ganz, R

    2014-01-01

    The use of joint-preserving surgery of the hip has been largely abandoned since the introduction of total hip replacement. However, with the modification of such techniques as pelvic osteotomy, and the introduction of intracapsular procedures such as surgical hip dislocation and arthroscopy, previously unexpected options for the surgical treatment of sequelae of childhood conditions, including developmental dysplasia of the hip, slipped upper femoral epiphysis and Perthes' disease, have become available. Moreover, femoroacetabular impingement has been identified as a significant aetiological factor in the development of osteoarthritis in many hips previously considered to suffer from primary osteoarthritis. As mechanical causes of degenerative joint disease are now recognised earlier in the disease process, these techniques may be used to decelerate or even prevent progression to osteoarthritis. We review the recent development of these concepts and the associated surgical techniques. PMID:24395304

  13. A review of long-term outcomes for late presenting developmental hip dysplasia.

    PubMed

    Thomas, S R Y W

    2015-06-01

    Successful management of late presenting hip dislocation in childhood is judged by the outcome not just at skeletal maturity but well beyond into adulthood and late middle age. This review considers different methods of treatment and looks critically at the handful of studies reporting long-term follow-up after successful reduction. PMID:26033050

  14. Hip Injuries and Disorders

    MedlinePlus

    ... because the ball-like top of your thigh bone moves within a cup-like space in your pelvis. Your hips are very stable. When they are healthy, it takes great force to hurt them. However, playing sports, running, ... of the hip causes weak bones that break easily. Both of these are common ...

  15. Formed HIP Can Processing

    SciTech Connect

    Clarke, Kester Diederik

    2015-07-27

    The intent of this report is to document a procedure used at LANL for HIP bonding aluminum cladding to U-10Mo fuel foils using a formed HIP can for the Domestic Reactor Conversion program in the NNSA Office of Material, Management and Minimization, and provide some details that may not have been published elsewhere. The HIP process is based on the procedures that have been used to develop the formed HIP can process, including the baseline process developed at Idaho National Laboratory (INL). The HIP bonding cladding process development is summarized in the listed references. Further iterations with Babcock & Wilcox (B&W) to refine the process to meet production and facility requirements is expected.

  16. Perilunate Injuries, Not Dislocated (PLIND)

    PubMed Central

    Herzberg, Guillaume

    2013-01-01

    Purpose We reviewed a series of equivalents of perilunate dislocations and fracture-dislocations (PLDs–PLFDs) in which there was no dislocation of the capitate from the lunate on the initial radiographs. We propose to include these injuries as a variant of perilunate dislocations that we have termed a perilunate injury, not dislocated (PLIND) lesion in a modified classification of perilunate injuries. Methods A review of the records of all acute perilunate injuries and displaced carpal fractures was done in a single-center university hospital wrist surgery unit over a 5-year period. All cases presenting at the acute stage with displaced fractures of scaphoid, lunate, triquetrum, or capitate along with scapholunate and/or lunotriquetral dissociation but no dislocation of the capitate from the lunate in the sagittal or coronal plane were reviewed and considered as PLIND lesions. Results We identified 11 patients with PLIND lesions. Three cases with clinical and radiological follow-up are presented. Discussion Equivalents of PLDs–PLFDs presenting without dislocation of the capitate from the lunate do exist. These injuries may be overlooked despite their severity. They require both osseous and ligamentous repair. Including them into an existing perilunate injuries classification highlights their recognition and enables a better understanding and treatment of both acute and chronic nondislocated perilunate injuries. Level of Evidence Level IV, retrospective case series. PMID:24436839

  17. Late-presenting developmental dysplasia of the hip in Jordanian males

    PubMed Central

    Samarah, Omar Q.; Hadidi, Fadi A. Al; Hamdan, Mohammad Q.; Hantouly, Ashraf T.

    2016-01-01

    Objectives: To describe the pattern of developmental dysplasia of the hip (DDH) in late presenting Jordanian male patients and identify the risk factors and associated findings. Methods: This is a retrospective study of 1145 male patients who attended the Pediatric Orthopedic Clinic for a DDH check up. This study was carried out in the Orthopedic Section, Special Surgery Department, Faculty of Medicine, The University of Jordan, Amman, Jordan between March 2011 and October 2014. Data was collected from medical records, and x-ray measurements were evaluated. Results: Of the 1145 male patients, 43 (3.75%) with 70 involved hips were diagnosed with late- presenting DDH. Being a first-born baby resulted in 41.9% increased risk for DDH. Cesarian delivery was significantly associated with an increased risk of hip dislocation (p=0.004) while normal delivery was significantly associated with acetabular dysplasia (p=0.004). No predictable risk factors were found in 44.2% patients with DDH. Bilateral cases were more common than unilateral cases: (26 [60.5%] versus 17 [39.5%]). Limited abduction was a constant finding in all dislocated hips (p<0.001). Associated conditions, such as club foot and congenital muscular torticollis were not observed. Conclusion: Cesarian section is a significant risk for dislocated hips while normal delivery is significantly associated with acetabular dysplasia. Bilateral DDH is more common than the unilateral. Club foot and torticollis were not observed in this series. PMID:26837397

  18. Comparison between 28 mm and 32 mm ceramic-on-ceramic bearings in total hip replacement.

    PubMed

    Lee, Y K; Ha, Y C; Koo, K H

    2014-11-01

    Large femoral heads have become popular in total hip replacement (THR) as a method of reducing the risk of dislocation. However, if large heads are used in ceramic-on-ceramic THR, the liner must be thinner, which may increase the risk of fracture. To compare the rates of ceramic fracture and dislocation between 28 mm and 32 mm ceramic heads, 120 hips in 109 patients (51 men and 58 women, mean age 49.2 years) were randomised to THR with either a 28 mm or a 32 mm ceramic articulation. A total of 57/60 hips assigned to the 28 mm group and 55/60 hips assigned to the 32 mm group were followed for at least five years. No ceramic component fractures occured in any patient in either group. There was one dislocation in the 32 mm group and none in the 28 mm group (p = 0.464). No hip had detectable wear, focal osteolysis or prosthetic loosening. In our small study the 32 mm ceramic articulation appeared to be safe in terms of ceramic liner fracture. PMID:25371457

  19. Total Hip Arthroplasty for the Paralytic and Non-paralytic Side in Patient with Residual Poliomyelitis

    PubMed Central

    Sonohata, Motoki; Kitajima, Masaru; Kawano, Shunsuke; Mawatari, Masaaki

    2016-01-01

    Background: Total hip arthroplasty (THA) for poliomyelitis is a problematic procedure due to difficulty in positioning the cup of the prosthesis in the true acetabulum and the risk of dislocation after THA due to the low muscle tone. Methods: We herein present a case of bilateral hip pain with a history of poliomyelitis. Radiograph showed bilateral hip osteoarthritis caused by hip dysplasia due to residual poliomyelitis in right hip joint or developing dysplasia of the hip joint in left hip joint. THA was performed to bilateral hip joints. Results: Six years after bilateral THA, bilateral hip pain significantly improved. Additionally, the muscle strength on the paralyzed right side partially improved. However, the muscle strength on the non-paralyzed left side did not significantly improve. No complications related to the surgery were observed. Conclusion: Promising early results were obtained for THA in our patient with residual poliomyelitis. However, surgeons should pay attention to the potential development of complications concerning THA that may arise due to the residual poliomyelitis. PMID:27347238

  20. Patellar Dislocations and Reduction Procedure.

    PubMed

    Ramponi, Denise

    2016-01-01

    Acute patellar dislocations are a common injury occurring in adolescents involved in sports and dancing activities. This injury usually occurs when the knee is in full extension and sustains a valgus stress on the knee. The medial patellofemoral ligament is the medial restraint that assists in stabilizing the patella from lateral dislocations. The patella usually dislocates laterally and is usually not difficult to reduce after patient evaluation and prereduction radiographs. After postreduction radiographs confirm proper position of the patella postreduction and the absence of fractures, the patient is usually treated conservatively with initial immobilization, orthopedic referral, and physical therapy. PMID:27139130

  1. Moving Dislocations in Disordered Alloys.

    SciTech Connect

    Marian, J; Caro, A

    2006-11-18

    Using atomistic simulations of dislocation motion in Ni and Ni-Au alloys we report a detailed study of the mobility function as a function of stress, temperature and alloy composition. We analyze the results in terms of analytic models of phonon radiation and their selection rules for phonon excitation. We find a remarkable agreement between the location of the cusps in the {sigma}-v relation and the velocity of waves propagating in the direction of dislocation motion. We identify and characterize three regimes of dissipation whose boundaries are essentially determined by the direction of motion of the dislocation, rather than by its screw or edge character.

  2. Are modern dual mobility cups a valuable option in reducing instability after primary hip arthroplasty, even in younger patients?

    PubMed

    Epinette, Jean-Alain; Béracassat, Richard; Tracol, Philippe; Pagazani, Gérard; Vandenbussche, Eric

    2014-06-01

    Hip instability after total hip replacement has been shown to be a critical cause of failure. The use of dual mobility has been classically restricted to patients "at risk", over 70 years of age. The question rises up about extended indications of so-called "modern" second generation dual mobility cups. This prospective multicenter study reports on first results at 2-5 years of the HA anatomical ADM cup upon two comparative groups of patients under 70 years (112 hips) vs. over 70 years of age (325 hips). No dislocation, migration, tilting, wear, or intra-prosthetic dislocation was recorded within each of the two cohorts. Survivorship for cup failures at this 4-year period was ideal at 100% in the younger patients, and 99.7% in the older group of patients. PMID:24444567

  3. Two Different Total Hip Arthroplasties for Hartofilakidis Type C1 Developmental Dysplasia of Hip in Adults

    PubMed Central

    Chu, Ya-Ming; Zhou, Yi-Xin; Han, Na; Yang, De-Jin

    2016-01-01

    Background: Total hip arthroplasty (THA) in developmental dysplasia of the hip (DDH) is more complex than the normal hip, with large replacement risks and many complications. Although nonosteotomy THA is convenient to perform, femoral osteotomy shortening can avoid blood vessel and nerve traction injuries. This study aimed to compare osteotomy THA with nonosteotomy to determine reasonable options for operative management of DDH. Methods: Data on 48 DDH patients who underwent THA were analyzed retrospectively. The patients were divided into two groups: Group A 29 cases (nonosteotomy), and group B 19 cases (osteotomy). Harris and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, limb length discrepancy (LLD), radiological data on the hip, and claudication were evaluated. Data were analyzed by using paired-sample Student's t-test, independent-sample Student's t-test, and Pearson's Chi-square test; the test level was α =0.05. Results: Postoperative Harris (90.7 ± 5.1) and WOMAC scores (88.0 ± 10.6) were significantly improved compared with preoperative Harris (44.8 ± 5.7) and WOMAC scores (42.0 ± 5.3) in group A (P < 0.05). Postoperative Harris (90.4 ± 2.8) and WOMAC scores (88.2 ± 5.9) were significantly improved compared with preoperative Harris (44.4 ± 4.2) and WOMAC scores (43.2 ± 4.3) in group B (P < 0.05). One case of dislocation occurred in group A; after closed reduction, dislocation did not recur. In group A, 2 patients developed cutaneous branch injury of the femoral nerve, which spontaneously recovered without treatment. Postoperative LLD >2 cm was seen in one case in group A and five cases in group B. Postoperative claudication showed no significant difference between the two groups (P > 0.05). No patients developed infection; postoperative X-rays showed that the location of the prosthesis was satisfactory, and the surrounding bone was not dissolved. Conclusions: THA is effective and safe for DDH. For unilateral high

  4. Hip arthroscopy in the setting of hip dysplasia

    PubMed Central

    Yeung, M.; Kowalczuk, M.; Simunovic, N.

    2016-01-01

    Objective Hip arthroscopy in the setting of hip dysplasia is controversial in the orthopaedic community, as the outcome literature has been variable and inconclusive. We hypothesise that outcomes of hip arthroscopy may be diminished in the setting of hip dysplasia, but outcomes may be acceptable in milder or borderline cases of hip dysplasia. Methods A systematic search was performed in duplicate for studies investigating the outcome of hip arthroscopy in the setting of hip dysplasia up to July 2015. Study parameters including sample size, definition of dysplasia, outcomes measures, and re-operation rates were obtained. Furthermore, the levels of evidence of studies were collected and quality assessment was performed. Results The systematic review identified 18 studies investigating hip arthroscopy in the setting of hip dysplasia, with 889 included patients. Criteria used by the studies to diagnose hip dysplasia and borderline hip dysplasia included centre edge angle in 72% of studies but the range of angles were quite variable. Although 89% of studies reported improved post-operative outcome scores in the setting of hip dysplasia, revision rates were considerable (14.1%), with 9.6% requiring conversion to total hip arthroplasty. Conclusion The available orthopaedic literature suggests that although improved outcomes are seen in hip arthroscopy in the setting of hip dysplasia, there is a high rate of re-operation and conversion to total hip arthroplasty. Furthermore, the criteria used to define hip dysplasia vary considerably among published studies. Cite this article: M. Yeung, M. Kowalczuk, N. Simunovic, O. R. Ayeni. Hip arthroscopy in the setting of hip dysplasia: A systematic review. Bone Joint Res 2016;5:225–231. DOI: 10.1302/2046-3758.56.2000533. PMID:27313136

  5. LACBED characterization of dislocations in Cu-Al-Ni shape memory alloys processed by powder metallurgy

    NASA Astrophysics Data System (ADS)

    Rodriguez, P. P.; Ibarra, A.; San Jean, J.; Morniro, J. P.; No, M. L.

    2003-10-01

    Powder metallurgy Cu-AI-Ni shape memory alloys show excellent thermomechanical properties, being the fracture behavior close to the one observed in single crystals. However, the microstructural mechanisms responsible of such behavior are still under study. In this paper we present the characterization of the dislocations present in these alloys by Large Angle Convergent Beam Electron Diffraction (LACBED) in two different stages of the elaboration process: after HIP compaction and after hot rolling.

  6. Dislocation sources in ordered intermetallics

    SciTech Connect

    Yoo, M.H.; Appel, F.; Wagner, R.; Mecking, H.

    1996-09-01

    An overview on the current understanding of dislocation sources and multiplication mechanisms is made for ordered intermetallic alloys of the L1{sub 2}, B2, and D0{sub 19} structures. In L1{sub 2} alloys, a large disparity of edge/screw segments in their relative mobility reduces the efficiency of a Frank-Read Type multiplication mechanism. In Fe-40%Al of the B2 structure, a variety of dislocation sources are available for <111> slip, including ones resulting from condensation of thermal vacancies. In NiAl with the relatively high APB energy, <100> dislocations may result from the dislocation decomposition reactions, the prismatic punching out from inclusion particles, and/or steps and coated layers of the surface. Internal interfaces often provide sites for dislocation multiplication, e.g., grain boundaries, sub-boundaries in Ni{sub 3}Ga, NiAl and Ti{sub 3}Al, and antiphase domain boundaries in Ti{sub 3}Al. As for the crack tip as a dislocation source, extended SISFs trailed by super-Shockley partials emanating form the cracks in Ni{sub 3}Al and Co{sub 3}Ti are discussed in view of a possible toughening mechanism.

  7. Clinical Implication of Diabetes Mellitus in Primary Total Hip Arthroplasty

    PubMed Central

    Chun, Young-Soo; Lee, Seung-Hyuk; Lee, Sang-Hoon; Cho, Yoon-Je

    2014-01-01

    Purpose The purpose of this study was to investigate the effect of diabetes mellitus on primary total hip arthroplasty by comparing the clinical outcomes of patients diagnosed to have diabetes mellitus before the operation with those without diabetes. Materials and Methods A total 413 patients who underwent unilateral cementless total hip arthroplasty from June 2006 to May 2009 were recruited and divided into diabetic and non-diabetic groups. The comparative analysis between the two groups was made. We evaluated Harris hip score, postoperative complications such as wound problem, surgical site infection, other medical complication and length of stay in hospital as clinical parameters. Radiographic evaluations were also included to determine loosening, dislocation and osteolysis. Results Patients with diabetes had an increased incidence of orthopaedic complications including surgical site infection and mortality, but other medical complications were not increased in diabetic patients. All complications after primary total hip arthroplasty were associated with diabetes mellitus, but the degree of diabetes was not associated with complications. Conclusion Diabetes mellitus increases incidence of orthopaedic complications, particularly deep infection, after cementless primary total hip arthroplasty.

  8. Hip replacement - discharge

    MedlinePlus

    ... a hip replacement and need antibiotics before any dental work. When to Call Your Doctor Call your health care provider if you have: A sudden increase in pain Chest pain or shortness of breath Frequent urination ...

  9. Hip joint replacement

    MedlinePlus

    Preventing venous thromboembolic disease in patients undergoing elective hip and knee arthopolasty: Evidence-based guideline and evidence report. American Association of Orthopaedic Surgeons. 2011. Harkess JW, Crockarell JR. Arthroplasty of ...

  10. Arthroscopic hip labral repair.

    PubMed

    Philippon, Marc J; Faucet, Scott C; Briggs, Karen K

    2013-05-01

    Labral tears in the hip may cause painful clicking or locking of the hip, reduced range of motion, and disruption to sports and daily activities. The acetabular labrum aids stabilization of the hip joint, particularly during hip motion. The fibrocartilaginous structure extends the acetabular rim and provides a suction seal around the femoroacetabular interface. Treatment options for labral tears include debridement, repair, and reconstruction. Repair of the labrum has been shown to have better results than debridement. Labral refixation is achieved with sutures anchored into the acetabular rim. The acetabular rim is trimmed either to correct pincer impingement or to provide a bleeding bed to improve healing. Labral repair has shown excellent short-term to midterm outcomes and allows patients to return to activities and sports. Arthroscopic rim trimming and labral refixation comprise an effective treatment for labral tears with an underlying diagnosis of femoroacetabular impingement and are supported by the peer-reviewed literature. PMID:23875153

  11. Hip fracture - discharge

    MedlinePlus

    ... hemiarthroplasty to replace the ball part of your hip joint. You should have received physical therapy while you were in the hospital or at a rehabilitation center before going home from the hospital.

  12. Ultrasound: Infant Hip

    MedlinePlus

    ... hip area, and images are recorded on a computer. The black-and-white images show the internal ... the images can be seen clearly on the computer screen. A technician (sonographer) trained in ultrasound imaging ...

  13. Hip flexor strain - aftercare

    MedlinePlus

    ... such as sprinting, kicking, and changing direction while running or moving, can stretch and tear the hip flexors. Runners, people who do martial arts, and football, soccer, and hockey players are more likely to have ...

  14. Minimally invasive hip replacement

    MedlinePlus

    ... Smits SA, Swinford RR, Bahamonde RE. A randomized, prospective study of 3 minimally invasive surgical approaches in total hip arthroplasty: comprehensive gait analysis. J Arthroplasty . 2008;23:68-73. PMID: 18722305 ...

  15. Treatment of hip dysplasia.

    PubMed

    Anderson, A

    2011-04-01

    Hip dysplasia is a common orthopaedic developmental disorder of dogs. This paper reviews the treatment options available for management of the condition in the skeletally immature and adult dog. PMID:21906059

  16. HIP osteoarthritis and work.

    PubMed

    Harris, E Clare; Coggon, David

    2015-06-01

    Epidemiological evidence points strongly to a hazard of hip osteoarthritis from heavy manual work. Harmful exposures may be reduced by the elimination or redesign of processes and the use of mechanical aids. Reducing obesity might help to protect workers whose need to perform heavy lifting cannot be eliminated. Particularly high relative risks have been reported in farmers, and hip osteoarthritis is a prescribed occupational disease in the UK for long-term employees in agriculture. Even where it is not attributable to employment, hip osteoarthritis impacts importantly on the capacity to work. Factors that may influence work participation include the severity of disease, the physical demands of the job, age and the size of the employer. Published research does not provide a strong guide to the timing of return to work following hip arthroplasty for osteoarthritis, and it is unclear whether patients should avoid heavy manual tasks in their future employment. PMID:26612242

  17. HIP OSTEOARTHRITIS AND WORK

    PubMed Central

    Harris, E Clare; Coggon, David

    2016-01-01

    Epidemiological evidence points strongly to a hazard of hip osteoarthritis from heavy manual work. Harmful exposures may be reduced by elimination or redesign of processes and use of mechanical aids. Reducing obesity might help to protect workers whose need to perform heavy lifting cannot be eliminated. Particularly high relative risks have been reported in farmers, and hip osteoarthritis is a prescribed occupational disease in the UK for long-term employees in agriculture. Even where it is not attributable to employment, hip osteoarthritis impacts importantly on capacity to work. Factors that may influence work participation include the severity of disease, the physical demands of the job, age, and the size of the employer. Published research does not provide a strong guide to the timing of return to work following hip arthroplasty for osteoarthritis, and it is unclear whether patients should avoid heavy manual tasks in their future employment. PMID:26612242

  18. Hip Resurfacing Implants.

    PubMed

    Cadossi, Matteo; Tedesco, Giuseppe; Sambri, Andrea; Mazzotti, Antonio; Giannini, Sandro

    2015-08-01

    EDUCATIONAL OBJECTIVES As a result of reading this article, physicians should be able to: 1. Describe the advantages of hip resurfacing. 2. Describe the disadvantages of hip resurfacing. 3. Identify the population in which hip resurfacing is most often indicated. 4. Demonstrate how to properly postoperatively manage patients with metal-on-metal prostheses. Hip resurfacing offers a suitable solution for young patients affected by hip disease who have high function demands and good bone quality. Bone stock preservation, restoration of the normal proximal femur anatomy, the lack of stress shielding, and the possibility of resuming sporting activity are proven advantages of hip resurfacing. However, there are some disadvantages, such as fracture of the femoral neck, onset of neck narrowing, and possible complications due to the metal-on-metal bearings, including pseudotumors, peri-implant osteolysis, and chronic elevation of metal ions in serum levels. Recent data suggest that the ideal candidate for hip resurfacing is an active male, younger than 65 years, with primary or posttraumatic osteoarthritis, and with a femoral head diameter larger than 50 to 54 mm. Based on these selection criteria, the literature reports implant survival to be similar to that of total hip arthroplasty. The current authors' experience confirms a low failure rate and excellent functional outcomes, with metal ion serum levels becoming stable over time in well-functioning implants. Proper surgical technique, correct patient selection, and the right choice of a well-established prosthetic model are essential elements for the long-term success of these implants. PMID:26270748

  19. HIP ARTHROSCOPY IN ATHLETES

    PubMed Central

    Polesello, Giancarlo Cavalli; Keiske Ono, Nelson; Bellan, Davi Gabriel; Honda, Emerson Kiyoshi; Guimarães, Rodrigo Pereira; Junior, Walter Riccioli; Do Val Sella, Guilherme

    2015-01-01

    To confirm the therapeutic importance of hip arthroplasty in athletes whose pain precludes sportive function of the hip joint, being able to minimize it to the extent of helping on the return of sports practice at satisfactory levels. Methods: 49 athlete patients (51 hips) submitted to hip arthroscopy complaining of pain and inability to practice sports were assessed. Follow-up time ranged from 12 to 74 months (mean: 39.0 months). Preoperatively, pain site, severity according to Facial Expression Scale (FES) and the degree of disability using the modified Harris Hip Score (HHS) were assessed. Different diagnoses were provided, which led to the indication of arthroscopy, such as femoralacetabular impact, acetabular lip injury not secondary to femoral-acetabular impact, etc. Postoperatively, the patients were assessed by using the same methods as used at baseline and by the subjective analysis of return to sports activities. Results: Based on pre-and postoperative HHS and FES, the statistical analysis showed significance between values. We found some improvement in all cases and return to sports activities at a satisfactory level in most of the cases. Conclusion: As a result of our study, we confirm that arthroscopy in athletes with local hip injuries is an effective technique, able to promote the return to sports practice in most of the cases, without pain, and with an effective joint function, provided well indicated. PMID:26998449

  20. Dislocations in Monolayers and Semiconductors.

    NASA Astrophysics Data System (ADS)

    Ren, Qiang

    1995-01-01

    Four different aspects of the properties of dislocations in monolayer and semiconductors have been investigated: (i) Using atomic relaxation techniques, dislocation dipoles of various sizes and orientations have been studied for monolayers with the Lennard-Jones potential (LJP) and the nearest-neighbour piecewise linear force (PLF) interactions. In the WP system the lower energy vacancy dipoles have over a wide range of angles an energy which is mainly a function of the vacancy content of the dipole. There is a competition between the elastic forces and the topological constraints which favour a five-fold coordinate vacancy (FCV) at the centre of each core. For the short range PLF system the lattice usually compresses upon the introduction of a dislocation, a consequence of the soft core of the interaction potential, and interstitial dipoles are lower in energy. For the long range LJP system the dislocations are mobile whereas for the PLF system they are pinned. The relevance of these results to existing theories of melting are discussed. (ii) Using generalized stacking-fault (GSF) energies obtained from first-principles density-functional calculations, a zero-temperature model for dislocations in silicon is constructed within the framework of a Peierls-Nabarro (PN) model. Core widths, core energies, PN pinning energies, and stresses are calculated for various possible perfect and imperfect dislocations. Both shuffle and glide sets are considered. 90^circ partials are shown to have a lower Peierls stress (PS) than 30 ^circ partials in accord with experiment. (iii) We have also studied by atomic relaxation techniques the properties of dislocations in silicon, modelled by the empirical potential of Stillinger and Weber. In order to compare with the preceding calculation no reconstruction is allowed. We find no evidence of dissociation in the shuffle dislocations. Within this model shuffle dislocations glide along their slipping planes. On the other hand, glide sets

  1. Rotational knee strain resulting in patellar dislocation. An experimental study in rabbits.

    PubMed

    Finsterbush, A

    1982-09-01

    The right lower extremities of 64 young rabbits were immobilized by a plaster spica. The animals developed a gait pattern, which included internal tibial rotation and adduction of the left (unimmobilized) tibia. Twenty-one of the animals developed medial patellar dislocation in the unimmobilized lower extremity. The mechanism of the patellar dislocation in this experimental model was possibly overstretching of the lateral colateral ligament and the lateral side of the joint capsule, associated with medial rotation of the tibia and the tibial tubercle. The direction of patellar pull when gliding inferiorly during knee flexion was shifted medially, resulting in patellar dislocation and secondarily, in formation of an exostosis under the displaced patella. Hip arthrodesis in humans, as a course of rotational instability of the contralateral knee, resembles some aspects of this experimental condition. PMID:7105585

  2. Microinstability of the Hip and the Splits Radiograph.

    PubMed

    Harris, Joshua D; Gerrie, Brayden J; Lintner, David M; Varner, Kevin E; McCulloch, Patrick C

    2016-01-01

    A normal hip has a natural tendency toward stability because of both osseous and soft tissue structures. Hip motion is primarily rotational around a center of rotation. When the femoral head and its center of rotation translate, with or without rotation, the inherent stability of the femoroacetabular articulation may be lost. The spectrum of hip instability ranges from subtle microinstability to traumatic dislocation. Microinstability may be the cause or the effect of several other hip pathologies. Soft tissue contributions to stability include the static capsule, dynamic musculotendinous units, and underlying generalized connective tissue (eg, Ehlers-Danlos). Osseous contributions include multiple femoral and acetabular radiographic coverage parameters. Iatrogenic contributions include an unrepaired capsulotomy, overresection of the acetabular rim (iatrogenic dysplasia), overresection of cam osteochondroplasty, iliopsoas tenotomy, labral debridement, and ligamentum teres debridement. Patients with hip microinstability often have deep groin pain, exhibited by a C sign. These patients frequently participate in flexibility sports and activities, such as ballet, gymnastics, figure skating, and martial arts. On physical examination, generalized hypermobility syndromes should be assessed, as should loss of log-roll external rotation recoil, excessive abduction, trochanteric-pelvic impingement, and abductor fatigue. Standard imaging, including plain radiographs, magnetic resonance imaging, and computed tomography, should be analyzed for all causes of hip pain. A new plain radiograph, the splits radiograph is introduced here, consistently showing lateral femoral head translation and creation of a vacuum sign, showing hip microinstability. The splits radiograph is illustrated in a 22-year-old female dancer who presented with bilateral deep anterolateral groin pain. PMID:26730687

  3. [Acute acromioclavicular dislocations].

    PubMed

    Riand, N; Sadowski, C; Hoffmeyer, P

    1999-12-01

    Acromioclavicular dislocations represent over 10% of acute traumatic injuries to the shoulder girdle. The mechanism is usually a direct impact on the shoulder with the arm in adduction, producing rupture of the acromioclavicular (AC) ligaments, then of the coracoclavicular (CC) ligament, with displacement of the lateral end of the clavicle. Rockwood described 6 grades of injury. Physical examination usually provides the diagnosis, which is confirmed by radiological examination. X-rays centered on the AC joint, if necessary with forceful adduction of both shoulders or under traction, are useful to evaluate the severity of the lesion. Grade I and II lesions are usually treated conservatively by simply immobilizing the arm for 3 to 4 weeks. Surgical treatment is usually advocated for grade IV, V and VI lesions: AC or CC fixation, sometimes associated with ligament repair, depending on the surgeons. AC pinning or C-C screw fixation are the techniques most often used. Management of grade III lesions remains controversial. Some authors advocate immediate surgical treatment in young, active patients, in heavy laborers and even in slender individuals. The choice of the operative technique is controversial, as no single technique has clearly proved to be superior to others. Other authors advocate conservative treatment, which gives functional results which patients consider quite acceptable, with faster recovery; patients should be informed that results are essentially similar, whatever the treatment. The possibility of performing secondary operations with good results in cases with failure of conservative management is a further argument in favor of applying conservative therapy first in acute injuries. PMID:10675933

  4. Anterior muscle sparing approach for total hip arthroplasty

    PubMed Central

    Moskal, Joseph T; Capps, Susan G; Scanelli, John A

    2013-01-01

    The purpose of this review is to examine the validity of positive claims regarding the direct anterior approach (DAA) with a fracture table for total hip arthroplasty. Recent literature regarding the DAA was searched and specific claims investigated including improved early outcomes, speed of recovery, component placement, dislocation rates, and complication rates. Recent literature is positive regarding the effects of total hip arthroplasty with the anterior approach. While the data is not definitive at present, patients receiving the anterior approach for total hip arthroplasty tend to recover more quickly and have improved early outcomes. Component placement with the anterior approach is more often in the “safe zone” than with other approaches. Dislocation rates tend to be less than 1% with the anterior approach. Complication rates vary widely in the published literature. A possible explanation is that the variance is due to surgeon and institutional experience with the anterior approach procedure. Concerns remain regarding the “learning curve” for both surgeons and institutions. In conclusion, it is not a matter of should this approach be used, but how should it be implemented. PMID:23362470

  5. Short-Term Results of Novel Constrained Total Hip Arthroplasty

    PubMed Central

    Pace, Thomas; Finley, Stephen; Snider, Rebecca; Looper, Jayme; Tanner, Stephanie

    2015-01-01

    Constrained acetabular components have only been recommended as a salvage option for the persistently unstable total hip arthroplasty (THA), due to limited range of motion and less than satisfactory component failure rates. This is a retrospective review of 137 patients with 154 consecutive primary constrained THAs performed between November 2003 and August 2007. We reviewed serial radiographs, postoperative complications, groin/thigh pain, and compared preoperative and postoperative Harris Hip Scores. With a mean follow-up of 6 years, there was 1.9% dislocation rate, 0% component failure rate, and 2.6% infection rate. Seven patients reported continued groin pain, and three had continued thigh pain. One patient showed radiographic evidence of 1 mm polyethylene wear. Radiographic review showed no evidence of osteolysis or stem subsidence. Harris Hip Scores improved from a mean of 68.8 (range 58-87) preoperatively to 98.9 (range 65-100) at final clinical assessment. This constrained acetabular prosthesis had a dislocation rate of less than 2%, with 0% component failure rate at a minimum of 2 years of follow-up suggesting this prosthesis may be a viable alternative for patients at risk for instability or those known to have recurrent instability. PMID:26330992

  6. Revision total hip replacement using the cement-in-cement technique for the acetabular component: technique and results for 60 hips.

    PubMed

    Brogan, K; Charity, J; Sheeraz, A; Whitehouse, S L; Timperley, A J; Howell, J R; Hubble, M J W

    2012-11-01

    The technique of femoral cement-in-cement revision is well established, but there are no previous series reporting its use on the acetabular side at the time of revision total hip replacement. We describe the technique and report the outcome of 60 consecutive acetabular cement-in-cement revisions in 59 patients at a mean follow-up of 8.5 years (5 to 12). All had a radiologically and clinically well-fixed acetabular cement mantle at the time of revision. During the follow-up 29 patients died, but no hips were lost to follow-up. The two most common indications for acetabular revision were recurrent dislocation (46, 77%) and to complement femoral revision (12, 20%). Of the 60 hips, there were two cases of aseptic loosening of the acetabular component (3.3%) requiring re-revision. No other hip was clinically or radiologically loose (96.7%) at the latest follow-up. One hip was re-revised for infection, four for recurrent dislocation and one for disarticulation of a constrained component. At five years the Kaplan-Meier survival rate was 100% for aseptic loosening and 92.2% (95% CI 84.8 to 99.6), with revision for any cause as the endpoint. These results support the use of cement-in-cement revision on the acetabular side in appropriate cases. Theoretical advantages include preservation of bone stock, reduced operating time, reduced risk of complications and durable fixation. PMID:23109626

  7. Dislocation Multi-junctions and Strain Hardening

    SciTech Connect

    Bulatov, V; Hsiung, L; Tang, M; Arsenlis, A; Bartelt, M; Cai, W; Florando, J; Hiratani, M; Rhee, M; Hommes, G; Pierce, T; Diaz de la Rubia, T

    2006-06-20

    At the microscopic scale, the strength of a crystal derives from the motion, multiplication and interaction of distinctive line defects--dislocations. First theorized in 1934 to explain low magnitudes of crystal strength observed experimentally, the existence of dislocations was confirmed only two decades later. Much of the research in dislocation physics has since focused on dislocation interactions and their role in strain hardening: a common phenomenon in which continued deformation increases a crystal's strength. The existing theory relates strain hardening to pair-wise dislocation reactions in which two intersecting dislocations form junctions tying dislocations together. Here we report that interactions among three dislocations result in the formation of unusual elements of dislocation network topology, termed hereafter multi-junctions. The existence of multi-junctions is first predicted by Dislocation Dynamics (DD) and atomistic simulations and then confirmed by the transmission electron microscopy (TEM) experiments in single crystal molybdenum. In large-scale Dislocation Dynamics simulations, multi-junctions present very strong, nearly indestructible, obstacles to dislocation motion and furnish new sources for dislocation multiplication thereby playing an essential role in the evolution of dislocation microstructure and strength of deforming crystals. Simulation analyses conclude that multi-junctions are responsible for the strong orientation dependence of strain hardening in BCC crystals.

  8. Dislocations and other topological oddities

    NASA Astrophysics Data System (ADS)

    Pieranski, Pawel

    2016-03-01

    We will show that the book Dislocations by Jacques Friedel, published half a century ago, can still be recommended, in agreement with the author's intention, as a textbook "for research students at University and for students at engineering schools as well as for research engineers". Indeed, today dislocations are known to occur not only in solid crystals but also in many other systems discovered more recently such as colloidal crystals or liquid crystals having periodic structures. Moreover, the concept of dislocations is an excellent starting point for lectures on topological defects occurring in systems equipped with order parameters resulting from broken symmetries: disclinations in nematic or hexatic liquid crystals, dispirations in chiral smectics or disorientations in lyotropic liquid crystals. The discussion of dislocations in Blue Phases will give us an opportunity to call on mind Sir Charles Frank, friend of Jacques Friedel since his Bristol years, who called these ephemeral mesophases "topological oddities". Being made of networks of disclinations, Blue Phases are similar to Twist Grain Boundary (TGB) smectic phases, which are made of networks of screw dislocations and whose existence was predicted by de Gennes in 1972 on the basis of the analogy between smectics and superconductors. We will stress that the book by Jacques Friedel contains seeds of this analogy.

  9. [Experimental research of the influences on the development of the hip joints with excavated acetabula].

    PubMed

    Sun, D; Chen, X; Tang, C

    1996-12-01

    There are still arguments about the operation excavated acetabula treatments for the congenital dislocation of the hip. To inquire into the influences on the development of the hip joints with excavated acetabula size, we divided 60 two-month-old chickens into three groups which were given incised dislocation and then reduction partly excavated the cartilages of the acetabula and excavated them totally to the left hips respectively. Contrasting observation of all the experimental chickens was taken on the right ones of their own. The second group achieved a fair function of the joint movement. Limited and slight adhesion was not affecting the development of the joints seriously. The third group had, on the contrary, poor functions because of the comprehensive adhesion in the acetabula. The surfaces of the acetabula were replaced by fabric tissue. The remaining or regenerating cartilage cells vary obviously under the light scope and the electronic scope. The heads of the femurs had changed similarly. It is suggested that in dealing with the congenital dislocation of the hip, excavating the acetabola cartilage is not advisable. Partly excavating is permitted when a limited bony process existing in the bottom of the acetabula. PMID:9590781

  10. Subtrochanteric osteotomy for femoral mal-torsion through a surgical dislocation approach

    PubMed Central

    Kamath, Atul F.; Ganz, Reinhold; Zhang, Hong; Grappiolo, Guido; Leunig, Michael

    2015-01-01

    Missed torsional femur deformities may contribute to reasons for failure after open and more likely arthroscopic hip preservation surgery. A number of surgical approaches have been described for addressing torsion abnormalities. This report describes a subtrochanteric osteotomy technique in a consecutive series of patients with complex hip pathologies, for which intertrochanteric osteotomy is not suitable and precise derotation is required. Subtrochanteric derotation was performed, always in combination with a surgical hip dislocation, in accordance with the authors’ preferred technique. Before osteotomy, a localized decortication was executed. Application of a 4.5-mm broad or narrow plate was undertaken with dynamic compression of the osteotomy. Twenty-eight consecutive subtrochanteric derotational osteotomies were performed in 26 patients. Twenty-one females and five males were treated at an average age of 21.4 years (range, 12–43). Underlying diagnoses included dysplasia, arthrogryposis, cerebral palsy, Down’s syndrome, instability and impingement. The decision to perform derotation was for antetorsion over 20° or less than 0° (retrotorsion). Patients were followed clinically and radiographically till final follow-up. All patients went on to successful osteotomy union. There were two initial failures: one delayed union prompting revision fixation in a chronic smoker and one plate failure due to self-accelerated weight-bearing in a patient status post successful contralateral derotational osteotomy. Rotational deformity of the femur must be considered in the patient undergoing hip preservation surgery. This technique of subtrochanteric derotational osteotomy, with adjunctive surgical hip dislocation, is applicable and reproducible in the setting of complex hip pathologies. Level of evidence: IV, case series. PMID:27011816

  11. Ipsilateral Fracture Shaft Femur with Neglected Dislocation of Prosthesis: A Case Report

    PubMed Central

    Jain, Mantu; Bihari, Amar Jyoti; Sriramka, Bhavna

    2013-01-01

    Introduction: Neglected hip dislocation is rare in today’s world and after prosthesis replacement even rarer finding. However such patients may not report to surgeons until they develop secondary complications. Management of such patient’s is a challenge to the treating surgeon and need to be tailored suiting to patient’s demands, expectations and constraints of financial resources. We did not find a similar case in the electronic and print media and therefore report this case which was innovatively managed. Case Report: A 60 year farmer presented with fracture shaft femur and ipsilateral dislocation prosthesis of right hip. He had a hemiarthroplasty done for fracture neck of femur in the past but used to walk with a lurch since he started to ambulate after discharge. However he was satisfied despite “some problems” which had caused shortening of his limb. The patient was informed of the various treatment options and their possible complications. He expressed his inability to afford a Total Hip Arthroplasty (THA) at any stage and consented for other options discussed with him. The patient was positioned supine and adductor tenotomy done. Next he was positioned laterally and the fracture was fixed with heavy duty broad dynamic compression plate and screws. The wound was temporarily closed. Now through the previous scar via posterior approach the hip was exposed. The prosthesis was found to be firmly fixed to the proximal femur. The acetabulum was cleared with fibrous tissue. All attempts the prosthesis to relocate the prosthesis failed after several attempts and it was best decided to leave alone. Post operatively period was uneventful. At follow up he refused for any further manoeuvre in future inform of heavy traction and attempts to reduce the same. At one year when he was walking unaided and his X-rays showed that fracture had well united his SF-36 score was PCS - 49.6 and MCS – 51.9. Conclusion: Ipsilateral shaft femur fracture in chronically

  12. Multiscale Theory of Dislocation Climb

    NASA Astrophysics Data System (ADS)

    Geslin, Pierre-Antoine; Appolaire, Benoît; Finel, Alphonse

    2015-12-01

    Dislocation climb is a ubiquitous mechanism playing a major role in the plastic deformation of crystals at high temperature. We propose a multiscale approach to model quantitatively this mechanism at mesoscopic length and time scales. First, we analyze climb at a nanoscopic scale and derive an analytical expression of the climb rate of a jogged dislocation. Next, we deduce from this expression the activation energy of the process, bringing valuable insights to experimental studies. Finally, we show how to rigorously upscale the climb rate to a mesoscopic phase-field model of dislocation climb. This upscaling procedure opens the way to large scale simulations where climb processes are quantitatively reproduced even though the mesoscopic length scale of the simulation is orders of magnitude larger than the atomic one.

  13. Multiscale Theory of Dislocation Climb.

    PubMed

    Geslin, Pierre-Antoine; Appolaire, Benoît; Finel, Alphonse

    2015-12-31

    Dislocation climb is a ubiquitous mechanism playing a major role in the plastic deformation of crystals at high temperature. We propose a multiscale approach to model quantitatively this mechanism at mesoscopic length and time scales. First, we analyze climb at a nanoscopic scale and derive an analytical expression of the climb rate of a jogged dislocation. Next, we deduce from this expression the activation energy of the process, bringing valuable insights to experimental studies. Finally, we show how to rigorously upscale the climb rate to a mesoscopic phase-field model of dislocation climb. This upscaling procedure opens the way to large scale simulations where climb processes are quantitatively reproduced even though the mesoscopic length scale of the simulation is orders of magnitude larger than the atomic one. PMID:26765003

  14. Surgical approach in primary total hip arthroplasty: anatomy, technique and clinical outcomes

    PubMed Central

    Petis, Stephen; Howard, James L.; Lanting, Brent L.; Vasarhelyi, Edward M.

    2015-01-01

    Total hip arthroplasty (THA) has revolutionized the treatment of hip arthritis. A number of surgical approaches to the hip joint exist, each with unique advantages and disadvantages. The most commonly used approaches include the direct anterior, direct lateral and posterior approaches. A number of technical intricacies allow safe and efficient femoral and acetabular reconstruction when using each approach. Hip dislocation, abductor insufficiency, fracture and nerve injury are complications of THA, although their relative risk varies by approach. Numerous clinical trials have sought to elicit differences in patient-reported outcomes, complication rates and return to function among the surgical approaches. This review outlines some of the technical pearls of performing a THA through either a direct anterior, direct lateral or posterior approach. A literature review outlines the impact of surgical approach on clinical outcomes and clinically relevant complication rates. PMID:25799249

  15. Hip injuries in children and adolescents.

    PubMed

    Craig, C L

    1980-10-01

    Hip injuries in children present a wide spectrum of problems. Frequently because of the severity of the trauma involved, other injuries may take precedence and may require modification of the usual approaches to treatment. However, certain precepts are essential to the successful treatment of these injuries and should be kept in mind regardless of the milieu in which they are found. In the child with a hip dislocation, the potential presence of an acetabular, femoral head, femoral shaft, patellar or tibial plateau fracture must always be considered. Specialized x-ray views are necessary for this evaluation. Laminography and arthrography may also be required. The essential feature of successful subsequent treatment is a gentle closed reduction performed within 24 hours of injury. Treatment of displaced fractures of the femoral neck remains an unresolved issue. Accurate reduction held with adequate internal fixation would appear to offer the best chance for a successful result. The possible complications of avascular necrosis, delayed union and non-union, coxa vara, premature closure of the epiphyseal plate, and shortening should be appreciated. Early institution of appropriate treatment may mitigate the ultimate effect of these potentially devastating problems. PMID:7454245

  16. The Hyperflexible Hip

    PubMed Central

    Weber, Alexander E.; Bedi, Asheesh; Tibor, Lisa M.; Zaltz, Ira; Larson, Christopher M.

    2015-01-01

    Context: Dance, gymnastics, figure skating, and competitive cheerleading require a high degree of hip range of motion. Athletes who participate in these sports use their hips in a mechanically complex manner. Evidence Acquisition: A search of the entire PubMed database (through December 2013) and additional searches of the reference lists of pertinent articles. Study Design: Systematic review. Level of Evidence: Level 3. Results: Whether innate or acquired, dancers and gymnasts have some hypermobility that allows their hips to be placed in potentially impinging or unstable positions required for their given activity. Such extremes of motion can result in both intra-articular and extra-articular impingement as well as compensatory osseous and muscular pathology. In addition, dancers and gymnasts are susceptible to impingement-induced instability. Dancers with innate generalized hyperlaxity are at increased risk of injury because of their activities and may require longer recovery times to return to play. Both nonoperative and operative treatments (arthroscopic and open) have an important role in returning flexibility athletes to their preoperative levels of sport and dance. Conclusion: Because of the extreme hip motion required and the compensatory soft tissue laxity in dancers and gymnasts, these athletes may develop instability, impingement, or combinations of both. This frequently occurs in the setting of subtle pathoanatomy or in patients with normal bony anatomy. With appropriate surgical indications and the correct operative technique, the treating surgeon can anticipate high levels of return to play for the gymnast and dancer with hip pain. PMID:26137181

  17. A patient-specific model of the biomechanics of hip reduction for neonatal Developmental Dysplasia of the Hip: Investigation of strategies for low to severe grades of Developmental Dysplasia of the Hip.

    PubMed

    Huayamave, Victor; Rose, Christopher; Serra, Sheila; Jones, Brendan; Divo, Eduardo; Moslehy, Faissal; Kassab, Alain J; Price, Charles T

    2015-07-16

    A physics-based computational model of neonatal Developmental Dysplasia of the Hip (DDH) following treatment with the Pavlik Harness (PV) was developed to obtain muscle force contribution in order to elucidate biomechanical factors influencing the reduction of dislocated hips. Clinical observation suggests that reduction occurs in deep sleep involving passive muscle action. Consequently, a set of five (5) adductor muscles were identified as mediators of reduction using the PV. A Fung/Hill-type model was used to characterize muscle response. Four grades (1-4) of dislocation were considered, with one (1) being a low subluxation and four (4) a severe dislocation. A three-dimensional model of the pelvis-femur lower limb of a representative 10 week-old female was generated based on CT-scans with the aid of anthropomorphic scaling of anatomical landmarks. The model was calibrated to achieve equilibrium at 90° flexion and 80° abduction. The hip was computationally dislocated according to the grade under investigation, the femur was restrained to move in an envelope consistent with PV restraints, and the dynamic response under passive muscle action and the effect of gravity was resolved. Model results with an anteversion angle of 50° show successful reduction Grades 1-3, while Grade 4 failed to reduce with the PV. These results are consistent with a previous study based on a simplified anatomically-consistent synthetic model and clinical reports of very low success of the PV for Grade 4. However our model indicated that it is possible to achieve reduction of Grade 4 dislocation by hyperflexion and the resultant external rotation. PMID:25957995

  18. Sideline Management of Joint Dislocations.

    PubMed

    Schupp, Christian M; Rand, Scott E; Hanson, Travis W; Lee, Bryan M; Jafarnia, Korsh; Jia, Yuhang; Moseley, J Bruce; Seaberg, John P; Seelhoefer, Gregory M

    2016-01-01

    Athletes can sustain a large variety of injuries from simple soft tissue sprains to complex fractures and joint dislocations. This article reviews and provides the most recent information for sports medicine professionals on the management of simple and complex joint dislocations, i.e., irreducible and/or associated with a fracture, from the sidelines without the benefit of imaging. For each joint, the relevant anatomy, common mechanisms, sideline assessment, reduction techniques, initial treatment, and potential complications will be discussed, which allow for the safe and prompt return of athletes to the field of play. PMID:27172077

  19. Bipolar dislocation of the clavicle.

    PubMed

    Jiang, Wei; Gao, Shu-Guang; Li, Yu-Sheng; Lei, Guang-Hua

    2012-11-01

    Bipolar dislocation of the clavicle at acromioclavicular and sternoclavicular joint is an uncommon traumatic injury. The conservative treatments adopted in the past is associated with redislocation dysfunction and deformity. A 41 years old lady with bipolar dislocation of right shoulder is treated surgically by open reduction and internal fixation by oblique T-plate at sternoclavicular joint and Kirschner wire stabilization at acromioclavicular joint. The patient showed satisfactory recovery with full range of motion of the right shoulder and normal muscular strength. The case reported in view of rarity and at 2 years followup. PMID:23325981

  20. Femoral head diameter considerations for primary total hip arthroplasty.

    PubMed

    Girard, J

    2015-02-01

    The configuration of total hip arthroplasty (THA) implants has constantly evolved since they were first introduced. One of the key components of THA design is the diameter of the prosthetic femoral head. It has been well established that the risk of dislocation is lower as the head diameter increases. But head diameter impacts other variables beyond joint stability: wear, cam-type impingement, range of motion, restoration of biomechanics, proprioception and groin pain. The introduction of highly cross-linked polyethylene and hard-on-hard bearings has allowed surgeons to implant large-diameter heads that almost completely eliminate the risk of dislocation. But as a result, cup liners have become thinner. With femoral head diameters up to 36 mm, the improvement in joint range of motion, delay in cam-type impingement and reduction in dislocation risk have been clearly demonstrated. Conversely, large-diameter heads do not provide any additional improvements. If an "ecologically sound" approach to hip replacement is embraced (e.g. keeping the native femoral head diameter), hip resurfacing with a metal-on-metal bearing must be carried out. The reliability of large-diameter femoral heads in the longer term is questionable. Large-diameter ceramic-on-ceramic bearings may be plagued by the same problems as metal-on-metal bearings: groin pain, squeaking, increased stiffness, irregular lubrication, acetabular loosening and notable friction at the Morse taper. These possibilities require us to be extra careful when using femoral heads with a diameter greater than 36 mm. PMID:25596984

  1. Hip joint replacement - series (image)

    MedlinePlus

    ... hip socket. The socket is usually made of metal. A liner that fits inside the socket. It ... usually plastic, but some surgeons use ceramic and metal. The liner allows the hip to move smoothly. ...

  2. Hip impingement: beyond femoroacetabular

    PubMed Central

    Bardakos, Nikolaos V.

    2015-01-01

    In the last 20 years, femoroacetabular impingement has been at the forefront of clinical practice as a cause of hip pain in young adults. As arthroscopic techniques for the hip continue to evolve, the possible presence of a new group of conditions creating mechanical conflict in and around the hip joint (ischiofemoral, subspine and iliopsoas impingement) has recently been elucidated whilst interest in already known ‘impingement’ syndromes (pelvic-trochanteric and pectineofoveal impingement) is now revived. This article attempts to increase awareness of these relatively uncommon clinical entities by describing their pathomorphology, contact mechanics, treatment and published results available to present. It is hoped that such knowledge will diversify therapeutic options for the clinician, thereby improving outcomes in a small but not negligible portion of patients with previously unexplained persistent symptoms. PMID:27011843

  3. A comparison of outcomes and dislocation rates using dual articulation cups and THA for intracapsular femoral neck fractures.

    PubMed

    Tarasevicius, Sarunas; Robertsson, Otto; Dobozinskas, Paulius; Wingstrand, Hans

    2013-01-01

    Total hip arthroplasty for intracapsular femoral neck fractures (FNF) is associated with a greater risk of dislocation. Dual articulation systems in this group of patients may provide better implant stability and a reduced dislocation rate. The aim of our study was to investigate FNF patients treated with dual articulation cups (DAC) and conventional THA and compare their clinical results at four months and one year after surgery. Our study compared femoral neck fracture patients treated with either DAC or conventional THA during two different time periods. Before surgery and during follow-up, the patients answered questions regarding their mobility, pain and usage of walking aids. Additionally at four-month and one-year follow-ups EQ-5D and HOOS questionnaires were applied for those patients qualifying for functional and quality of life analysis. Out of 125 femoral neck fracture patients 58 were treated with DAC and 67 with conventional THA. At four months and one year follow-up the HOOS and EQ-5D results did not differ significantly between DAC and conventional THA. Five hips in the THA group were revised for recurrent dislocation and two had a single dislocation. One year after surgery, the functional result of DAC and conventional THA are comparable but DAC have a lower risk of dislocation. PMID:23397197

  4. Modular hybrid total hip arthroplasty. Experimental study in dogs

    PubMed Central

    2011-01-01

    Background This prospective experimental study evaluated the surgical procedure and results of modular hybrid total hip arthroplasty in dogs. Methods Ten skeletally mature healthy mongrel dogs with weights varying between 19 and 27 kg were used. Cemented modular femoral stems and uncemented porous-coated acetabular cups were employed. Clinical and radiographic evaluations were performed before surgery and at 30, 60, 90, 120, 180 and 360 days post-operation. Results Excellent weight bearing was noticed in the operated limb in seven dogs. Dislocation followed by loosening of the prosthesis was noticed in two dogs, which were therefore properly treated with a femoral head osteotomy. Femoral fracture occurred in one dog, which was promptly treated with full implant removal and femoral osteosynthesis. Conclusions The canine modular hybrid total hip arthroplasty provided excellent functionality of the operated limb. PMID:21736758

  5. Drift of dislocation tripoles under ultrasound influence.

    PubMed

    Murzaev, R T; Bachurin, D V; Nazarov, A A

    2016-01-01

    Numerical simulations of dynamics of different stable dislocation tripoles under influence of monochromatic standing sound wave were performed. The basic conditions necessary for the drift and mutual rearrangements between dislocation structures were investigated. The dependence of the drift velocity of the dislocation tripoles as a function of the frequency and amplitude of the external influence was obtained. The results of the work can be useful in analysis of motion and self-organization of dislocation structure under ultrasound influence. PMID:26278625

  6. Light scattering from dislocations in silicon

    NASA Astrophysics Data System (ADS)

    Monier, Vanessa; Capello, Luciana; Kononchuk, Oleg; Pichaud, Bernard

    2010-11-01

    Nondecorated glide dislocations in Czochralski grown silicon have been studied by laser scattering tomography technique. Dependence of intensity of scattered light on polarization of the incident light has been measured for different orientations of the dislocation line and Burgers vector. Detailed theory of light scattering by dislocation in silicon crystals is presented. It is shown that by combination of polarization and tomography measurements it is possible to determine slip system of nondecorated mixed dislocation in Si.

  7. The dancer's hip.

    PubMed

    Sammarco, G J

    1983-11-01

    Conditions that occur in the dancer's hip fall into the following categories: poor training; conditions that occur as the result of normal use; overuse syndromes, including tendinitis and myositis; and conditions referring pain to the hip. Dancers are highly motivated and goal oriented and often suppress symptoms for long periods, making diagnosis and treatment difficult. Observing the dancer at work and understanding his art are emphasized, and a practical guide to therapy is presented. Development of proper dance technique and a proper flexibility program can decrease the incidence of injuries. PMID:6652698

  8. [Complications of hip arthroscopies].

    PubMed

    Dienst, M; Grün, U

    2008-11-01

    Surgical complications of hip arthroscopies are rare in the hands of experienced hip arthroscopists. However, when performed by beginners and in more demanding situations such as marginal distraction of the head and socket and technically advanced procedures, the risk increases. This report describes possible complications which may happen during positioning and traction, portal placement, and diagnostic and therapeutic procedures. Possible causes of soft tissue lesions of the portal area, perineum and foot, intra-articular lesions of the labrum and cartilage, direct and traction-related indirect neurovascular lesions, and other rare complications are analyzed. PMID:18854972

  9. 14 CFR 314.6 - Qualifying dislocation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Qualifying dislocation. 314.6 Section 314.6 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) PROCEDURAL REGULATIONS EMPLOYEE PROTECTION PROGRAM General § 314.6 Qualifying dislocation. A qualifying dislocation is...

  10. The Finnish Arthroplasty Register: report of the hip register.

    PubMed

    Puolakka, T J; Pajamäki, K J; Halonen, P J; Pulkkinen, P O; Paavolainen, P; Nevalainen, J K

    2001-10-01

    The Finnish Arthroplasty Register was established in 1980. Between 1980 and 1999, 62,841 primary and 12,224 revision total hip arthroplasties (THA) were recorded. The annual number of both primary and revision THA has increased: in 1999, the incidence of primary THAs was 93/100,000. 174 implant designs have been used, but the 6 commonest implants comprised 82% in 1999. Since the late 1980s, more than 40% of the hips were inserted without cement. Over 47% of the cementless primary hip prostheses were used in patients younger than 60 years and over 93% of the cemented primary hips were used in patients 60 years or older. The 10-year survival rate was 72 (95% CI 67-76)% in patients younger than 55 years and 90 (89-91)% in patients older than 70 years. The commonest reasons for revision were aseptic loosening (65%), dislocation (9%) and infection (7%). In revisions, the 5-year survival of the cementless hip prosthesis improved over time: it was 85 (82-87)% in 1985-1989, 89 (88-91)% in 1990-1994 and 92 (88-95)% in 1995-1999. There are striking differences between the Arthroplasty Registers of Scandinavia as regards the end-point definition of survival. The Finnish Arthroplasty Register considers all reasons for revisions as the end-point of survival, but the Swedish register takes into account only aseptic loosening, so direct comparisons between registers are not possible. Recent data from the Finnish Arthroplasty Register indicate that the results of total hip replacements are improving in Finland. With the civic registration number, one can link and match data files. For example, with use of the Finnish Cancer Register, we found no increase in the risk of cancer after a THA. PMID:11728068

  11. Cementless Revision Total Hip Arthroplasty with Ceramic Articulation

    PubMed Central

    Yang, Jong-Hyuck; Yang, Seong-Jo; Kang, Joon-Soon

    2015-01-01

    Purpose The results of ceramic-on-ceramic (CoC) bearing surfaces in primary total hip arthroplasty (THA) were well known. However, it was not known in revision THA. The purpose of this study is to report the results of revision THA with ceramic articulation. Materials and Methods A total of 112 revision THAs were evaluated. The mean age at the time of surgery was 51.6 years (27.7 to 84.2 years). The mean duration of the follow-up periods was 6.3 years (2.3 to 11.4 years). Results The Harris hip scores improved from an average of 56.2 at the index surgery to an average of 93.3 at the last follow-up (P<0.001). None of hips showed osteolysis or ceramic head fracture. One hip showed aseptic loosening in the acetabular component with squeaking that caused a re-revision. There were nine cases of dislocation. The survivorship at 5 years was 94.5% (95% confidence interval, 87.9% to 97.6%) with revision for any reason as the endpoint and 100% with femoral revision. Conclusion The ceramic articulation is one of good bearing options for revision THA in patients with a long life expectancy. PMID:27536630

  12. Hip resurfacing: a large, US single-surgeon series.

    PubMed

    Brooks, P J

    2016-01-01

    Hip resurfacing has been proposed as an alternative to traditional total hip arthroplasty in young, active patients. Much has been learned following the introduction of metal-on-metal resurfacing devices in the 1990s. The triad of a well-designed device, implanted accurately, in the correct patient has never been more critical than with these implants. Following Food and Drug Administration approval in 2006, we studied the safety and effectiveness of one hip resurfacing device (Birmingham Hip Resurfacing) at our hospital in a large, single-surgeon series. We report our early to mid-term results in 1333 cases followed for a mean of 4.3 years (2 to 5.7) using a prospective, observational registry. The mean patient age was 53.1 years (12 to 84); 70% were male and 91% had osteoarthritis. Complications were few, including no dislocations, no femoral component loosening, two femoral neck fractures (0.15%), one socket loosening (0.08%), three deep infections (0.23%), and three cases of metallosis (0.23%). There were no destructive pseudotumours. Overall survivorship at up to 5.7 years was 99.2%. Aseptic survivorship in males under the age of 50 was 100%. We believe this is the largest United States series of a single surgeon using a single resurfacing system. PMID:26733633

  13. Mid-term Results of Revision Total Hip Arthroplasty Using Modular Cementless Femoral Stems

    PubMed Central

    Jang, Hyung-Gyu; Min, Byung-Woo; Ye, Hee-Uk; Lim, Kyung-Hwan

    2015-01-01

    Purpose The purpose of this study was to evaluate the clinical and radiological results of revision total hip arthroplasty using modular distal fixation stems for proximal femoral deficiency. Materials and Methods Forty-five patients (47 hips) were analyzed more than 24 months after revision total hip arthroplasty that used modular distal fixation stems and was performed between 2006 and 2012. There were proximal femoral defects in all cases. Preoperative femoral defect classification revealed Paprosky type II in 31 cases, type IIIA in 7, and type IIIB in 9. The mean duration of follow-up was 53.4 (25-100) months. We evaluated the Harris hip score (HHS), walking ability according to Koval as clinical parameters, stem stability, and stem position change as radiographic parameters. Kaplan-Meier survival analysis was performed. Results The average HHS improved form 39.5 points to 91.3 points and walking ability also improved in most cases; all patients had stable fixation of the femoral stem. Postoperative complications included 5 cases of infection and 2 cases of dislocation. The survival rate with the end point of re-revision surgery due to infection or dislocation was 86% after 8-year follow-up. Conclusion Cementless revision total hip arthroplasty using modular femoral stems is useful because the stems can be stably fixed on the diaphyseal portion of the femur, which has relatively good bone quality at mid-term follow-up. PMID:27536616

  14. Interaction of <1 0 0> dislocation loops with dislocations studied by dislocation dynamics in α-iron

    NASA Astrophysics Data System (ADS)

    Shi, X. J.; Dupuy, L.; Devincre, B.; Terentyev, D.; Vincent, L.

    2015-05-01

    Interstitial dislocation loops with Burgers vector of <1 0 0> type are formed in α-iron under neutron or heavy ion irradiation. As the density and size of these loops increase with radiation dose and temperature, these defects are thought to play a key role in hardening and subsequent embrittlement of iron-based steels. The aim of the present work is to study the pinning strength of the loops on mobile dislocations. Prior to run massive Dislocation Dynamics (DD) simulations involving experimentally representative array of radiation defects and dislocations, the DD code and its parameterization are validated by comparing the individual loop-dislocation reactions with those obtained from direct atomistic Molecular Dynamics (MD) simulations. Several loop-dislocation reaction mechanisms are successfully reproduced as well as the values of the unpinning stress to detach mobile dislocations from the defects.

  15. A 61-year-old woman develops polyuria after hip revision

    PubMed Central

    Shaheen, Aisha; Dobish, Mark; Gleason, Vanessa; Setren, Adam; Stem, Jonathan; Kohl, Benjamin A.

    2016-01-01

    A 61-year-old previously healthy woman developed progressive hearing and visual loss over a period of 2–3 months prior to admission. Her medical/surgical history was remarkable for a left hip arthroplasty 11 years ago requiring revision approximately 6 months prior to admission. After dislocating the revised hip, she re-presented to her surgeon and underwent a closed reduction. Several weeks following the reduction, the patient began having polyuria and symptoms of hearing and vision loss along with numbness in her extremities and abdominal region. PMID:27170702

  16. Developmental dysplasia of the hip: diagnosis and management to 18 months.

    PubMed

    Clarke, Nicholas M P

    2014-01-01

    Developmental dysplasia of the hip represents a spectrum of disease ranging from transient neonatal instability to established dislocation. It is accepted that female sex, breech presentation, and family history are risk factors for the disease. Early diagnosis by clinical examination or ultrasound imaging is emphasized, with splint treatment ideally commencing by 6 weeks of age. Treatment using the Pavlik harness is successful in up to 90% of patients. Ultrasound imaging is the gold standard for monitoring a patient during harness wear. Failed splintage or late presentation usually necessitates surgical intervention depending on the patient's age and the severity of the hip dysplasia and displacement. PMID:24720316

  17. Efficacy of Debridement for Early Periprosthetic Joint Infection after Hip Arthroplasty

    PubMed Central

    Kim, Jong Hoon; Chun, Sung Kwang; Yoon, Yong Cheol; Lakhotia, Devendra

    2014-01-01

    Purpose In early prosthetic joint infection after hip arthroplasty, debridement with prosthesis retention may be performed for implant salvage, but the reported success rates are highly variable. Hence we reviewed the outcome of radical debridement and retention of prosthesis using established diagnostic criteria and surgical procedures in relation to significant variables including clinical characteristics, pathogenicity, and antibiotic treatment. Materials and Methods We retrospectively reviewed 20 patients (11 men and 9 women) with early prosthetic joint infection after unilateral hip arthroplasty, treated by radical debridement with retention of prosthesis from January 2000 to May 2011. Average follow-up period was 55 months (12-178 months). The outcome was evaluated and analyzed based on recurrence of infection and clinical (Harris hip score) and radiological criteria. Results Pathogens were isolated from 11 hips (methicillin-resistant Staphylococcus aureus [MRSA] in three, methicillin-resistant Staphylococcus epidermidis [MRSE] in two, methicillin-sensitive Staphylococcus aureus [MSSA] in one, Acinetobacter baumannii in two, Enterococcus faecalis in two patients, and Enterococcus, Citrobacter species in one). The mean duration of antibiotic administration was 43.5 days. Recurrence of infection was not observed in any case. Average Harris hip score was 91 points at the last follow-up. Revision surgery was not required for any reason including implant failure. Dislocation occurred in two hips after debridement and was treated conservatively. Conclusion Radical debridement with prosthesis retention is an effective procedure for early prosthetic joint infection after hip arthroplasty in carefully selected patients and with early diagnosis.

  18. Cartilage restoration of the hip using fresh osteochondral allograft: resurfacing the potholes.

    PubMed

    Khanna, V; Tushinski, D M; Drexler, M; Backstein, D B; Gross, A E; Safir, O A; Kuzyk, P R

    2014-11-01

    Cartilage defects of the hip cause significant pain and may lead to arthritic changes that necessitate hip replacement. We propose the use of fresh osteochondral allografts as an option for the treatment of such defects in young patients. Here we present the results of fresh osteochondral allografts for cartilage defects in 17 patients in a prospective study. The underlying diagnoses for the cartilage defects were osteochondritis dissecans in eight and avascular necrosis in six. Two had Legg-Calve-Perthes and one a femoral head fracture. Pre-operatively, an MRI was used to determine the size of the cartilage defect and the femoral head diameter. All patients underwent surgical hip dislocation with a trochanteric slide osteotomy for placement of the allograft. The mean age at surgery was 25.9 years (17 to 44) and mean follow-up was 41.6 months (3 to 74). The mean Harris hip score was significantly better after surgery (p<0.01) and 13 patients had fair to good outcomes. One patient required a repeat allograft, one patient underwent hip replacement and two patients are awaiting hip replacement. Fresh osteochondral allograft is a reasonable treatment option for hip cartilage defects in young patients. PMID:25381401

  19. Early Attempts at Hip Arthroplasty

    PubMed Central

    Gomez, Pablo F; Morcuende, Jose A

    2005-01-01

    Over the last three centuries, treatment of hip arthritides has evolved from rudimentary surgery to modern total hip arthroplasty (THA), which is considered one of the most successful surgical interventions ever developed. We here review the history of the early hip arthroplasty procedures for hip arthritis that preceded Charley total hip arthroplasty. An evaluation of such past enterprises is relevant, and reminds us of the ephemeral nature of human industriousness, and how medical research and procedures are not isolated developments, but correlate to the social, economical, and cultural framework of their time. PMID:16089067

  20. Hip Arthroscopy in The Athlete

    PubMed Central

    2007-01-01

    Sports related injuries to the hip have received relatively little attention, in the part because the clinical assessment, imaging studies, and surgical techniques are less sophisticated. The evolution of hip arthroscopy has offered a less invasive technique that allows for recognition and treatment of hip pathologies that previously went unrecognized. The success of hip arthoscopy is dependent on proper patient selection based on the patient's history and diagnosis. The purpose of this clinical commentary is to outline mechanisms of injury and specific lesions that can be addresses using hip arthoscopy. PMID:21509141

  1. The athlete's hip and groin.

    PubMed

    Tammareddi, Kumar; Morelli, Vincent; Reyes, Miguel

    2013-06-01

    Groin and hip injuries are seen in athletes who perform quick directional changes and cutting movements. Because forces generated through athletic performance are transferred through the hip, injuries to these areas may limit athletes with mild pain or lead to career-ending injuries. The anatomy of the hip and groin is complex and symptoms often overlap. This article discusses some athletic causes, but other medical conditions may be associated with hip and groin pain as well. Updates in evaluation and treatment are discussed for adductor strains, hip osteoarthritis, femoroacetabular impingement, sports hernia, osteitis pubis, and obturator nerve entrapment. PMID:23668647

  2. Hip Arthroscopy: A Brief History.

    PubMed

    Kandil, Abdurrahman; Safran, Marc R

    2016-07-01

    Hip arthroscopy is a fast-growing and evolving field. Like knee and shoulder arthroscopy, hip arthroscopy began as a diagnostic procedure and then progressed to biopsy and resection of abnormalities. Subsequently, it has evolved to repair of various tissues and treatment of underlying causes. As the understanding of the hip joint and its associated pathophysiology grows, indications will continue to expand for this diagnostic and therapeutic modality. This article outlines the historic developments of hip arthroscopy, including advancements in instrumentation and techniques from the days of the first hip arthroscopies to the present day. PMID:27343387

  3. TEM study on relationship between stacking faults and non-basal dislocations in Mg

    NASA Astrophysics Data System (ADS)

    Zhang, Dalong; Jiang, Lin; Schoenung, Julie M.; Mahajan, Subhash; Lavernia, Enrique J.

    2015-12-01

    Recent interest in the study of stacking faults and non-basal slip in Mg alloys is partly based on the argument that these phenomena positively influence mechanical behaviour. Inspection of the published literature, however, reveals that there is a lack of fundamental information on the mechanisms that govern the formation of stacking faults, especially I1-type stacking faults (I1 faults). Moreover, controversial and sometimes contradictory mechanisms have been proposed concerning the interactions between stacking faults and dislocations. Therefore, we describe a fundamental transmission electron microscope investigation on Mg 2.5 at. % Y (Mg-2.5Y) processed via hot isostatic pressing (HIP) and extrusion at 623 K. In the as-HIPed Mg-2.5Y, many and dislocations, together with some dislocations were documented, but no stacking faults were observed. In contrast, in the as-extruded Mg-2.5Y, a relatively high density of stacking faults and some non-basal dislocations were documented. Specifically, there were three different cases for the configurations of observed stacking faults. Case (I): pure I2 faults; Case (II): mixture of I1 faults and non-basal dislocations having component, together with basal dislocations; Case (III): mixture of predominant I2 faults and rare I1 faults, together with jog-like dislocation configuration. By comparing the differences in extended defect configurations, we propose three distinct stacking fault formation mechanisms for each case in the context of slip activity and point defect generation during extrusion. Furthermore, we discuss the role of stacking faults on deformation mechanisms in the context of dynamic interactions between stacking faults and non-basal slip.

  4. Small diameter acetabulum and femoral head in total hip arthroplasty for developmental dysplasia of the hip, with no femoral osteotomy.

    PubMed

    Verettas, Dionysios-Alexandros; Chloropoulou, Pelagia; Xarchas, Konstantinos; Drosos, Georgios; Ververidis, Athanasios; Kazakos, Konstantinos

    2015-01-01

    We present the results of 66 total hip arthroplasties in 62 patients of mean age 46 years (24-74 years), with developmental dysplasia of the hip. In all cases the centre of rotation of the new hip was positioned at the site of the true acetabulum. In all patients cementless press fit acetabular components of small diameter (42-44 mm) were used, articulating exclusively with a 22.25 mm modular metal femoral head, without the use of bone grafts or shortening osteotomies of the femur. Despite the use of small diameter femoral heads the rate of dislocation was 3%. After an average follow-up period of 9 years (4-18 years), no revisions were required for infection, loosening or wear or implant migration. Osteolytic lesions were seen in the periacetabular region in 3 patients who were symptom free. A total of 2 revisions were required for instability and 2 patients had the wires of their trochanteric osteotomy removed because of bursitis. Leg length inequality was improved in 55% of the patients and one postoperative transient sciatic nerve lesion settled within 4 months. We believe that in patients with painful dysplastic hips, the use of small diameter implants with the centre of rotation at the true acetabulum, can give very satisfactory results, without any supplementary procedures. PMID:25907394

  5. INL HIP Plate Fabrication

    SciTech Connect

    B. H. Park; C. R. Clark; J. F. Jue

    2010-02-01

    This document outlines the process used to bond monolithic fuel plates by Hot Isostatic Pressing (HIP). This method was developed at Idaho National Laboratory (INL) for the Reduced Enrichment for Research and Test Reactors (RERTR) program. These foils have been used in a number of irradiation experiments in support of the United States Global Threat Reduction Initiative (GTRI) program.

  6. Hip Morphology Characterization

    PubMed Central

    Barrientos, Cristián; Diaz, Jorge; Brañes, Julian; Chaparro, Felipe; Barahona, Maximiliano; Salazar, Alfonso; Hinzpeter, Jaime

    2014-01-01

    Background: Femoroacetabular impingement (FAI) is the result of a mechanical conflict in the hip joint, and its diagnosis is based on clinical and radiological parameters. To our knowledge, there are no published studies describing the radiologic characteristics of FAI in Latin American populations. Purpose: To describe the radiological features associated with FAI in an asymptomatic Chilean population. Study Design: Cross-sectional study; Level of evidence, 3. Methods: We prospectively recruited asymptomatic patients with no history or symptoms of hip pathology who underwent abdomen-pelvis computed tomography (CT) for a nonorthopaedic indication. The acetabular and femoral parameters related to FAI were measured. Results: We studied 101 subjects (202 hips) with a mean age of 36.8 ± 14.4 years. The mean center-edge angle was 39.4° ± 7.2°. The crossover sign was present in 34 cases (33.7%). The mean alpha angle was 49.7° ± 8.3°. Depending on the cut points chosen for FAI-related parameters, between 39.6% and 69.3% of an asymptomatic Chilean population were found to have morphological features related to FAI. Conclusion: Our findings suggest that the proposed pathological threshold values in the literature cannot be extrapolated to a Chilean population, and this must be taken into consideration when evaluating Latin American patients with hip pain. PMID:26535273

  7. COMPLICATIONS IN HIP ARTHROSCOPY

    PubMed Central

    Contreras, Marcos Emílio Kuschnaroff; Hoffmann, Rafael Barreiros; de Araújo, Lúcio Cappelli Toledo; Dani, William Sotau; José Berral, Francisco

    2015-01-01

    Objectives: To determine the prevalence of complications in a series of consecutive cases of hip arthroscopy; to assess the progression of the sample through a learning curve; and to recognize the causes of complications in arthroscopic hip operations. Method: 150 consecutive cases that underwent hip arthroscopy between May 2004 and December 2008 were evaluated. The complications encountered were classified in three ways: organic system affected, severity and groups of 50 consecutive cases. The data were analyzed by means of descriptive statistics and Fisher's exact test. Results: We observed 15 complications in this study (10%): ten were neurological, two were osteoarticular, one was vascular-ischemic and two were cutaneous. In the classification of severity, three were classified as major, 12 as intermediate and none as minor. The incidence of complications over the course of the learning curve did not present any statistically significant difference (p = 0.16). Conclusions: Hip arthroscopy is a surgical procedure that involves low morbidity, but which presents complications in some cases. These complications are frequently neurological and transitory, and mainly occur because of joint traction. The complication rate did not decrease with progression of our sample. PMID:27022521

  8. Osteochondral Autograft from the Ipsilateral Femoral Head by Surgical Dislocation for Treatment of Femoral Head Fracture Dislocation: A Case Report.

    PubMed

    Won, Yougun; Lee, Gi Soo; Kim, Sang Bum; Kim, Sun Joong; Yang, Kyu Hyun

    2016-11-01

    As anatomical reduction of the articular surface of femoral head fractures and restoration of damaged cartilage are essential for good long-term results, many treatment options have been suggested, including fixation of the fracture using various surgical exposures and implants, as well as arthroscopic irrigation and debridement, bone marrow stimulating techniques, osteochondral allograft, autograft, and autogenous chondrocyte implantation. We report a case of osteochondral autograft harvested from its own femoral articular surface through surgical hip dislocation. The osteochondral graft was harvested from the inferior non-weight-bearing articular surface and grafted to the osteochondral defect. One year later, the clinical and radiological results were good, without the collapse of the femoral head or arthritic change. This procedure introduced in our case is considered convenient and able to lessen surgical time without morbidity of the donor site associated with the harvest. PMID:27593886

  9. Solute drag on perfect and extended dislocations

    NASA Astrophysics Data System (ADS)

    Sills, R. B.; Cai, W.

    2016-04-01

    The drag force exerted on a moving dislocation by a field of mobile solutes is studied in the steady state. The drag force is numerically calculated as a function of the dislocation velocity for both perfect and extended dislocations. The sensitivity of the non-dimensionalized force-velocity curve to the various controlling parameters is assessed, and an approximate analytical force-velocity expression is given. A non-dimensional parameter S characterizing the strength of the solute-dislocation interaction, the background solute fraction ?, and the dislocation character angle ?, are found to have the strongest influence on the force-velocity curve. Within the model considered here, a perfect screw dislocation experiences no solute drag, but an extended screw dislocation experiences a non-zero drag force that is about 10 to 30% of the drag on an extended edge dislocation. The solutes can change the spacing between the Shockley partials in both stationary and moving extended dislocations, even when the stacking fault energy remains unaltered. Under certain conditions, the solutes destabilize an extended dislocation by either collapsing it into a perfect dislocation or causing the partials to separate unboundedly. It is proposed that the latter instability may lead to the formation of large faulted areas and deformation twins in low stacking fault energy materials containing solutes, consistent with experimental observations of copper and stainless steel containing hydrogen.

  10. Discrete dislocation dynamics simulations in a cylinder

    NASA Astrophysics Data System (ADS)

    Li, Maosheng; Gao, Chan; Xu, Jianing

    2015-02-01

    Mechanical properties of material are closely related to the motion of dislocations, and predicting the interactions and resulting collective motion of dislocations is a major task in understanding and modelling plastically deforming materials. A discrete dislocation dynamics model is used to describe the orientation substructure within the microstructure. Discrete dislocation dynamics simulations in three dimensions have been used to examine the role of dislocation multiplication and mobility on the plasticity in small samples under uniaxial compression. In this paper we describe the application of the dislocation dynamics simulations in a cylindrical geometry. The boundary conditions for the simulation were estimated from the distribution of the geometrically necessary dislocation density which was obtained from the orientation map. Numerical studies benchmark could validate the accuracy of the algorithms and the importance of handling the singularity correctly. The results of the simulation explain the formation of the experimentally observed substructure.

  11. Dislocation boundaries and active slip systems

    SciTech Connect

    Wert, J.A.; Hansen, N.

    1995-11-01

    Part of the dislocations which have participated in the plastic deformation of a polycrystalline metal are stored in dislocation boundaries in a two- or three-dimensional arrangement. The dislocation in such boundaries can be analyzed by determining the misorientation between neighboring crystallites and the boundary orientation. Information about the dislocations in the boundaries can also be obtained by an analysis of active slip systems based on the crystallite orientation and the imposed stress or strain state in combination with appropriate constraint conditions. In the present paper an analysis of the boundary dislocation structure and of the slip systems has been conducted for pure aluminium cold-rolled to a von Mises strain of 0.41. The results show that a substantial majority of dislocations in different types of dislocation boundaries are from the primary and conjugate slip system in the adjoining crystallites. A basis is therefore provided for integrating deformation structure observations with plastic deformation behavior.

  12. Theory of interacting dislocations on cylinders

    NASA Astrophysics Data System (ADS)

    Amir, Ariel; Paulose, Jayson; Nelson, David R.

    2013-04-01

    We study the mechanics and statistical physics of dislocations interacting on cylinders, motivated by the elongation of rod-shaped bacterial cell walls and cylindrical assemblies of colloidal particles subject to external stresses. The interaction energy and forces between dislocations are solved analytically, and analyzed asymptotically. The results of continuum elastic theory agree well with numerical simulations on finite lattices even for relatively small systems. Isolated dislocations on a cylinder act like grain boundaries. With colloidal crystals in mind, we show that saddle points are created by a Peach-Koehler force on the dislocations in the circumferential direction, causing dislocation pairs to unbind. The thermal nucleation rate of dislocation unbinding is calculated, for an arbitrary mobility tensor and external stress, including the case of a twist-induced Peach-Koehler force along the cylinder axis. Surprisingly rich phenomena arise for dislocations on cylinders, despite their vanishing Gaussian curvature.

  13. Effect of high hip center on stress for dysplastic hip.

    PubMed

    Nie, Yong; Pei, Fuxing; Li, Zongming

    2014-07-01

    High hip center reconstruction has been advocated in treating deficient acetabulum. However, there is no consensus on the clinical outcome of this technique. In addition, it remains unclear to what extend this technique restores the normal hip biomechanics. The goal of this study was to investigate stress above the acetabular dome in response to a range of high hip center positioning for Crowe type I and II hip dysplasia. This study consisted of 2 main parts, radiologic and biomechanical. Pelvic radiographs of 18 patients were studied to determine the amount of displacement of the hip center in the superior direction compared with the normal side. Second, qualitative and quantitative changes in stress on cortical and trabecular bone in the region of the acetabular dome as a result of superior displacement of the hip center were analyzed with subject-specific finite element models. The results showed that the range of the hip center position in the superior direction for Crowe type I and II hip dysplasia was 0 to 15 mm above the contralateral femoral head center. When superior displacement of the hip center exceeded 5 mm above the anatomic hip center, cortical bone mass on the 2 thickest cross-sections above the acetabular dome decreased quickly and the stress value on posterolateral cortical bone was obviously lower than the normal level. This study showed that to restore the normal load above the acetabular dome, there is a limit of 5 mm above the anatomic hip center for high hip center acetabular reconstruction for Crowe type I and II hip dysplasia. PMID:24992059

  14. Do larger femoral heads improve the functional outcome in total hip arthroplasty?

    PubMed

    Allen, Charlotte L; Hooper, Gary J; Frampton, Christopher M A

    2014-02-01

    Use of larger diameter femoral heads has been popularised in total hip arthroplasty (THA). Recent studies have implicated larger femoral heads in early failure. We evaluated what effect the size of the femoral head had on the early functional outcome in order to determine the optimal head size for the maximal functional outcome. There were 726 patients who underwent elective THA and were divided into 3 groups according to head size then compared with respect to functional outcome scores and dislocation rates. This study failed to show that increasing the size of the femoral head significantly improved the functional outcome at 1 year after total hip arthroplasty but that the use of a 36 mm or greater femoral head did reduce the dislocation rate. PMID:23891058

  15. Preoperative planning and postoperative evaluation of total hip arthroplasty that takes combined anteversion.

    PubMed

    Imai, Hiroshi; Miyawaki, Joji; Kamada, Tomomi; Takeba, Jun; Mashima, Naohiko; Miura, Hiromasa

    2016-07-01

    The purpose of this study was to investigate whether postoperative combined anteversion (CA) can be kept within the safe zone while using cementless total hip arthroplasty (THA) using the operative technique which prepares the socket first for developmental dysplasia of the hip (DDH), by estimating the anteversion of the metaphyseal fit stem using preoperative three-dimensional (3D) computerized planning and by adjusting the anteversion of the socket using a navigation system that considers CA. Our subjects were 65 patients (65 hips) that had undergone cementless THA for DDH that could be observed for 1 year or more. Clinical assessments were made using the Japanese Orthopaedic Association's (JOA) hip score. For a radiological evaluation, we investigated 3D-planned stem versions, postoperative stem versions, preoperative and postoperative CA, and the relationship between CA and dislocation tendencies with temporary intraoperative reductions. JOA hip scores improved from 52.3 ± 11.4 points to 88.9 ± 8.6 points. CT evaluations revealed that 3D-planned stem versions were strongly correlated with postoperative stem versions (r = 0.80; p < 0.01). Preoperative CA was 50.5° ± 7.2°, and postoperative CA was 41.3° ± 8.6°. Postoperative CA was kept within the safe zone in 61 hips. No intraoperative dislocation tendencies were observed in any hips. By estimating the anteversion of the cementless metaphyseal fit stem using 3D planning preoperatively and adjusting the angle of anteversion of the socket using a navigation system that considers CA intraoperatively, postoperative CA can very frequently be kept within the safe zone, even with cementless THA using the operative technique which prepares the socket first for DDH. PMID:27154291

  16. Neonatal clinical screening of the hip in the diagnosis of developmental dysplasia of the hip: a 15-year prospective longitudinal observational study.

    PubMed

    Mace, J; Paton, R W

    2015-02-01

    Over a 15-year prospective period, 201 infants with a clinically unstable hip at neonatal screening were subsequently reviewed in a 'one stop' clinic where they were assessed clinically and sonographically. Their mean age was 1.62 weeks (95% confidence interval (CI) 1.35 to 1.89). Clinical neonatal hip screening revealed a sensitivity of 62% (mean, 62.6 95%CI 50.9 to 74.3), specificity of 99.8% (mean, 99.8, 95% CI 99.7 to 99.8) and positive predictive value (PPV) of 24% (mean, 26.2, 95% CI 19.3 to 33.0). Static and dynamic sonography for Graf type IV dysplastic hips had a 15-year sensitivity of 77% (mean, 75.8 95% CI 66.9 to 84.6), specificity of 99.8% (mean, 99.8, 95% CI 99.8 to 99.8) and a PPV of 49% (mean, 55.1, 95% CI 41.6 to 68.5). There were 36 infants with an irreducible dislocation of the hip (0.57 per 1000 live births), including six that failed to resolve with neonatal splintage. Most clinically unstable hips referred to a specialist clinic are female and stabilise spontaneously. Most irreducible dislocations are not identified from this neonatal instability group. There may be a small subgroup of females with instability of the hip which may be at risk of progression to irreducibility despite early treatment in a Pavlik harness. A controlled study is required to assess the value of neonatal clinical screening programmes. PMID:25628293

  17. Simultaneous shoulder and elbow dislocation

    PubMed Central

    Çobanoğlu, Mutlu; Yumrukcal, Feridun; Karataş, Cengiz; Duygun, Fatih

    2014-01-01

    Ipsilateral shoulder and elbow dislocation is very rare and only six articles are present in the literature mentioning this kind of a complex injury. With this presentation we aim to emphasise the importance of assessing the adjacent joints in patients with trauma in order not to miss any accompanying pathologies. We report a case of a 43-year-old female patient with ipsilateral right shoulder and elbow dislocation treated conservatively. The patient reported elbow pain when first admitted to emergency service but she was diagnosed with simultaneous ipsilateral shoulder and elbow injury and treated conservatively. As a more painful pathology may mask the additional ones, one should hasten to help before performing a complete evaluation. Any harm caused to the patient due to this reason would not be a complication but a malpractice. PMID:24859563

  18. Dislocation creep of dry quartz

    NASA Astrophysics Data System (ADS)

    Kilian, Rüdiger; Heilbronner, Renée.; Holyoke, Caleb W.; Kronenberg, Andreas K.; Stünitz, Holger

    2016-05-01

    Small-scale shear zones within the Permian Truzzo meta-granite developed during the Alpine orogeny at amphibolite facies conditions. In these shear zones magmatic quartz deformed by dislocation creep and recrystallized dynamically by grain boundary migration with minor subgrain rotation recrystallization to a grain size of around 250-750 µm, consistent with flow at low differential stresses. Fourier transform infrared (FTIR) spectroscopy reveals very low water contents in the interior of recrystallized grains (in the form of discrete OH peaks, ~20 H/106Si and very little broad band absorption, <100 H/106Si). The spectral characteristics are comparable to those of dry Brazil quartz. In FTIR spectra, magmatic quartz grains show a broad absorption band related with high water concentrations only in those areas where fluid inclusions are present while other areas are dry. Drainage of fluid inclusions and synkinematic growth of hydrous minerals indicates that a hydrous fluid has been available during deformation. Loss of intragranular water during grain boundary migration recrystallization did not result in a microstructure indicative of hardening. These FTIR measurements provide the first evidence that quartz with extremely low intragranular water contents can deform in nature by dislocation creep at low differential stresses. Low intragranular water contents in naturally deformed quartz may not be necessarily indicative of a high strength, and the results are contrary to implications taken from deformation experiments where very high water contents are required to allow dislocation creep in quartz. It is suggested that dislocation creep of quartz in the Truzzo meta-granite is possible to occur at low differential stresses because sufficient amounts of intergranular water ensure a high recovery rate by grain boundary migration while the absence of significant amounts of intragranular water is not crucial at natural conditions.

  19. Misfit dislocation nucleation in heteroepitaxy

    NASA Astrophysics Data System (ADS)

    Trushin, Oleg; Ying, See Chen; Granato, Enzo; Ala-Nissila, Tapio

    2001-03-01

    We have studied atomic mechanisms of misfit dislocation nucleation in heteroepitaxy with semiempirical potentials. Many-body mechanisms of stress relaxation are systematically investigated with Lennard-Jones potential in 2D and 3D cases. Energy barriers for dislocation nucleation are estimated using modern methods for saddle point search (Nudged Elastic Band [1], Eigenvector Following [2] and others). Moreover, new simple and effective method for transition paths searching is proposed. Based on the data the critical thickness of film is estimated as a function of film-substrate lattice misfit. Moreover, to make the study more realistic we used EAM [3] potentials in simulations of Pd/Cu and Cu/Pd systems. We show that the dislocations nucleate more easily in compressive than tensile strained films, and in fcc(111) orientation rather than in fcc(100). These findings are in agreement with recent experimental and theoretical works. 1. H. Jonsson, G. Mills and K. W. Jacobsen, in Classical and Quantum Dynamics in Condensed Phase Simulations, ed. by B. J. Berne, G. Ciccotti, and D. F. Coker (World Scientific, Singapore, 1998). 2. L. J. Munro and D. J. Wales, Phys. Rev. B v59, 3969 (1999), and references therein. 3. S. M. Foiles, M. I. Baskes, and M. S. Daw, Phys. Rev. B v33, 7983 (1986).

  20. Visualization of dislocation dynamics in colloidal crystals.

    PubMed

    Schall, Peter; Cohen, Itai; Weitz, David A; Spaepen, Frans

    2004-09-24

    The dominant mechanism for creating large irreversible strain in atomic crystals is the motion of dislocations, a class of line defects in the crystalline lattice. Here we show that the motion of dislocations can also be observed in strained colloidal crystals, allowing detailed investigation of their topology and propagation. We describe a laser diffraction microscopy setup used to study the growth and structure of misfit dislocations in colloidal crystalline films. Complementary microscopic information at the single-particle level is obtained with a laser scanning confocal microscope. The combination of these two techniques enables us to study dislocations over a range of length scales, allowing us to determine important parameters of misfit dislocations such as critical film thickness, dislocation density, Burgers vector, and lattice resistance to dislocation motion. We identify the observed dislocations as Shockley partials that bound stacking faults of vanishing energy. Remarkably, we find that even on the scale of a few lattice vectors, the dislocation behavior is well described by the continuum approach commonly used to describe dislocations in atomic crystals. PMID:15448265

  1. Three-dimensional formulation of dislocation climb

    NASA Astrophysics Data System (ADS)

    Gu, Yejun; Xiang, Yang; Quek, Siu Sin; Srolovitz, David J.

    2015-10-01

    We derive a Green's function formulation for the climb of curved dislocations and multiple dislocations in three-dimensions. In this new dislocation climb formulation, the dislocation climb velocity is determined from the Peach-Koehler force on dislocations through vacancy diffusion in a non-local manner. The long-range contribution to the dislocation climb velocity is associated with vacancy diffusion rather than from the climb component of the well-known, long-range elastic effects captured in the Peach-Koehler force. Both long-range effects are important in determining the climb velocity of dislocations. Analytical and numerical examples show that the widely used local climb formula, based on straight infinite dislocations, is not generally applicable, except for a small set of special cases. We also present a numerical discretization method of this Green's function formulation appropriate for implementation in discrete dislocation dynamics (DDD) simulations. In DDD implementations, the long-range Peach-Koehler force is calculated as is commonly done, then a linear system is solved for the climb velocity using these forces. This is also done within the same order of computational cost as existing discrete dislocation dynamics methods.

  2. Cementless total hip arthroplasty.

    PubMed

    Morscher, E W

    1983-12-01

    The differences between prostheses fixed with and without cement are mainly in the design and nature of the surface implant. The shapes of the sockets to be implanted without cement show a wide variety: cylinder, square, conus, and ellipsoid with and without threads. The hemispheric shape, however, which was chosen for the acetabular component of the isoelastic hip joint, does not disturb the natural form and function of the hip joint since the outer surface is closely adapted to the original subchondral bone layer. The noncemented cup is secured by threads, pegs, screws, etc., and by ingrowth of bony tissue in the grooves of the surfaces. Most femoral stems are based on the self-locking principle. All prosthetic models incorporate attempts to increase the surface of the stem (ribs, wings, corrugations, rims, etc.). There is a tendency to use less rigid elastic implants instead of the well known rigid metallic prostheses. The aim is to overcome the problems of stress protection and stress concentration observed with rigid implants. For the biomechanical integration of an implant, the properties of the surface, especially macroporosity and microporosity, are important. Most European models of noncemented endoprostheses are based on macroporosity (porometal, madreporic, etc.). The increase in implant surface area achieved with macroscopic perforations and recesses is relatively minor compared with the possibilities offered by microporosity ("alumine fritée," Proplast, fiber-metal, etc.). The best indication for use of a cementless hip endoprosthesis is in revision arthroplasty. The lost bone stock is replaced by bone grafts, thereby creating a situation comparable with that of a primary arthroplasty. Clinical experience with noncemented hip endoprostheses is, to date, promising, although the observation time for most models is short. PMID:6357588

  3. 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... 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)...

  4. 21 CFR 888.3360 - Hip joint femoral (hemi-hip) metallic 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 femoral (hemi-hip) metallic cemented or... Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis is a device intended to be...

  5. 21 CFR 888.3360 - Hip joint femoral (hemi-hip) metallic 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) metallic cemented or... Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis is a device intended to be...

  6. 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... 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)...

  7. 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... 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)...

  8. 21 CFR 888.3360 - Hip joint femoral (hemi-hip) metallic 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 femoral (hemi-hip) metallic cemented or... Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis is a device intended to be...

  9. Heterotopic ossification after hip arthroscopy

    PubMed Central

    Amar, Eyal; Sharfman, Zachary T.; Rath, Ehud

    2015-01-01

    Heterotopic ossification (HO) after hip arthroscopy is the abnormal formation of mature lamellar bone within extra skeletal soft tissues. HO may lead to pain, impaired range of motion and possibly revision surgery. There has been a substantial amount of recent research on the pathophysiology, prophylaxis and treatment of HO associated with open and arthroscopic hip surgery. This article reviews the literature on the aforementioned topics with a focus on their application in hip arthroscopy. PMID:27011859

  10. Heterotopic ossification after hip arthroscopy.

    PubMed

    Amar, Eyal; Sharfman, Zachary T; Rath, Ehud

    2015-12-01

    Heterotopic ossification (HO) after hip arthroscopy is the abnormal formation of mature lamellar bone within extra skeletal soft tissues. HO may lead to pain, impaired range of motion and possibly revision surgery. There has been a substantial amount of recent research on the pathophysiology, prophylaxis and treatment of HO associated with open and arthroscopic hip surgery. This article reviews the literature on the aforementioned topics with a focus on their application in hip arthroscopy. PMID:27011859

  11. Kinetics of a Fast Moving Partial Dislocation

    NASA Astrophysics Data System (ADS)

    Daphalapurkar, Nitin; Ramesh, K. T.

    2013-03-01

    Plastic deformation in materials under extreme stresses requires a kinetic description of moving dislocations. The velocities with which the partial dislocations can propagate under an applied stress has implications for plasticity at high strain rates, specifically, the rate of plastic deformation and the rate-sensitivity. In this work, we focus our attention on motion of a twinning partial dislocation in a face-centered cubic (FCC) material, Ni. We use molecular dynamics simulations to simulate the velocity of a propagating twinning partial dislocation and investigate the effect of applied shear stress. Results suggest a limiting value for the speeds of a propagating partial dislocation. The material speeds based on the nonlinear part (under high stresses) of the stress-strain curve are shown to have an influence on the velocity with which a partial dislocation can propagate. Predicted velocities from simulations will be related to observations from high rate impact experiments. Supported by Hopkins Extreme Materials Institute

  12. Capsular Management in Hip Arthroscopy.

    PubMed

    Harris, Joshua D

    2016-07-01

    The hip capsule is a highly complex anatomic structure, which influences normal hip motion and biomechanics. A dynamic stabilizing capsular contribution exists in the iliocapsularis and gluteus minimus, among other musculotendinous structures crossing the joint. Variable types and sizes of capsulotomy are necessary to sufficiently visualize and address the bony and soft tissue pathologic source of symptoms. Unrepaired capsulotomies may leave the hip significantly unstable to variable degrees. Capsular closure is a necessary part of a comprehensive arthroscopic hip preservation procedure. Greater titration of the degree of plication may be performed for patients with risk factors for postoperative instability. PMID:27343391

  13. Anterior Hip Joint Force Increases with Hip Extension, Decreased Gluteal Force, or Decreased Iliopsoas Force

    PubMed Central

    Lewis, Cara L.; Sahrmann, Shirley A.; Moran, Daniel W.

    2008-01-01

    Abnormal or excessive force on the anterior hip joint may cause anterior hip pain, subtle hip instability and a tear of the acetabular labrum. We propose that both the pattern of muscle force and hip joint position can affect the magnitude of anterior joint force and thus possibly lead to excessive force and injury. The purpose of this study was to determine the effect of hip joint position and of weakness of the gluteal and iliopsoas muscles on anterior hip joint force. We used a musculoskeletal model to estimate hip joint forces during simulated prone hip extension and supine hip flexion under 4 different muscle force conditions and across a range of hip extension and flexion positions. Weakness of specified muscles was simulated by decreasing the modeled maximum force value for the gluteal muscles during hip extension and the iliopsoas muscle during hip flexion. We found that decreased force contribution from the gluteal muscles during hip extension and the iliopsoas muscle during hip flexion resulted in an increase in the anterior hip joint force. The anterior hip joint force was greater when the hip was in extension than when the hip was in flexion. Further studies are warranted to determine if increased utilization of the gluteal muscles during hip extension and of the iliopsoas muscle during hip flexion, and avoidance of hip extension beyond neutral would be beneficial for people with anterior hip pain, subtle hip instability, or an anterior acetabular labral tear. PMID:17707385

  14. Coupled dislocation and martensitic phase transformation dynamics

    NASA Astrophysics Data System (ADS)

    Barros, Kipton; Acharya, Amit; Lookman, Turab

    2013-03-01

    We present a field theoretic model that couples dislocation dynamics and plasticity with martensitic phase transformation. Dislocations produce long-range stress via incompatibility of the elastic-distortion field. Phase transformations are modeled with a non-convex elastic potential that contains the crystal symmetries of austenite and martensite phases. We discuss the effects of dislocation dynamics on material microstructure produced under extreme conditions.

  15. Robust atomistic calculation of dislocation line tension

    NASA Astrophysics Data System (ADS)

    Szajewski, B. A.; Pavia, F.; Curtin, W. A.

    2015-12-01

    The line tension Γ of a dislocation is an important and fundamental property ubiquitous to continuum scale models of metal plasticity. However, the precise value of Γ in a given material has proven difficult to assess, with literature values encompassing a wide range. Here results from a multiscale simulation and robust analysis of the dislocation line tension, for dislocation bow-out between pinning points, are presented for two widely-used interatomic potentials for Al. A central part of the analysis involves an effective Peierls stress applicable to curved dislocation structures that markedly differs from that of perfectly straight dislocations but is required to describe the bow-out both in loading and unloading. The line tensions for the two interatomic potentials are similar and provide robust numerical values for Al. Most importantly, the atomic results show notable differences with singular anisotropic elastic dislocation theory in that (i) the coefficient of the \\text{ln}(L) scaling with dislocation length L differs and (ii) the ratio of screw to edge line tension is smaller than predicted by anisotropic elasticity. These differences are attributed to local dislocation core interactions that remain beyond the scope of elasticity theory. The many differing literature values for Γ are attributed to various approximations and inaccuracies in previous approaches. The results here indicate that continuum line dislocation models, based on elasticity theory and various core-cut-off assumptions, may be fundamentally unable to reproduce full atomistic results, thus hampering the detailed predictive ability of such continuum models.

  16. Dislocation-driven surface dynamics on solids.

    PubMed

    Kodambaka, S; Khare, S V; Swiech, W; Ohmori, K; Petrov, I; Greene, J E

    2004-05-01

    Dislocations are line defects that bound plastically deformed regions in crystalline solids. Dislocations terminating on the surface of materials can strongly influence nanostructural and interfacial stability, mechanical properties, chemical reactions, transport phenomena, and other surface processes. While most theoretical and experimental studies have focused on dislocation motion in bulk solids under applied stress and step formation due to dislocations at surfaces during crystal growth, very little is known about the effects of dislocations on surface dynamics and morphological evolution. Here we investigate the near-equilibrium dynamics of surface-terminated dislocations using low-energy electron microscopy. We observe, in real time, the thermally driven nucleation and shape-preserving growth of spiral steps rotating at constant temperature-dependent angular velocities around cores of dislocations terminating on the (111) surface of TiN in the absence of applied external stress or net mass change. We attribute this phenomenon to point-defect migration from the bulk to the surface along dislocation lines. Our results demonstrate that dislocation-mediated surface roughening can occur even in the absence of deposition or evaporation, and provide fundamental insights into mechanisms controlling nanostructural stability. PMID:15129275

  17. Multiscale modeling of dislocation-precipitate interactions in Fe: From molecular dynamics to discrete dislocations

    NASA Astrophysics Data System (ADS)

    Lehtinen, Arttu; Granberg, Fredric; Laurson, Lasse; Nordlund, Kai; Alava, Mikko J.

    2016-01-01

    The stress-driven motion of dislocations in crystalline solids, and thus the ensuing plastic deformation process, is greatly influenced by the presence or absence of various pointlike defects such as precipitates or solute atoms. These defects act as obstacles for dislocation motion and hence affect the mechanical properties of the material. Here we combine molecular dynamics studies with three-dimensional discrete dislocation dynamics simulations in order to model the interaction between different kinds of precipitates and a 1/2 <111 > {110 } edge dislocation in BCC iron. We have implemented immobile spherical precipitates into the ParaDis discrete dislocation dynamics code, with the dislocations interacting with the precipitates via a Gaussian potential, generating a normal force acting on the dislocation segments. The parameters used in the discrete dislocation dynamics simulations for the precipitate potential, the dislocation mobility, shear modulus, and dislocation core energy are obtained from molecular dynamics simulations. We compare the critical stresses needed to unpin the dislocation from the precipitate in molecular dynamics and discrete dislocation dynamics simulations in order to fit the two methods together and discuss the variety of the relevant pinning and depinning mechanisms.

  18. Elbow Dislocations: A Review Ranging from Soft Tissue Injuries to Complex Elbow Fracture Dislocations

    PubMed Central

    Zellner, Johannes; Koller, Michael; Nerlich, Michael; Lenich, Andreas

    2013-01-01

    This review on elbow dislocations describes ligament and bone injuries as well as the typical injury mechanisms and the main classifications of elbow dislocations. Current treatment concepts of simple, that is, stable, or complex unstable elbow dislocations are outlined by means of case reports. Special emphasis is put on injuries to the medial ulnar collateral ligament (MUCL) and on posttraumatic elbow stiffness. PMID:24228180

  19. Multiscale modeling of dislocation-precipitate interactions in Fe: From molecular dynamics to discrete dislocations.

    PubMed

    Lehtinen, Arttu; Granberg, Fredric; Laurson, Lasse; Nordlund, Kai; Alava, Mikko J

    2016-01-01

    The stress-driven motion of dislocations in crystalline solids, and thus the ensuing plastic deformation process, is greatly influenced by the presence or absence of various pointlike defects such as precipitates or solute atoms. These defects act as obstacles for dislocation motion and hence affect the mechanical properties of the material. Here we combine molecular dynamics studies with three-dimensional discrete dislocation dynamics simulations in order to model the interaction between different kinds of precipitates and a 1/2〈111〉{110} edge dislocation in BCC iron. We have implemented immobile spherical precipitates into the ParaDis discrete dislocation dynamics code, with the dislocations interacting with the precipitates via a Gaussian potential, generating a normal force acting on the dislocation segments. The parameters used in the discrete dislocation dynamics simulations for the precipitate potential, the dislocation mobility, shear modulus, and dislocation core energy are obtained from molecular dynamics simulations. We compare the critical stresses needed to unpin the dislocation from the precipitate in molecular dynamics and discrete dislocation dynamics simulations in order to fit the two methods together and discuss the variety of the relevant pinning and depinning mechanisms. PMID:26871192

  20. Identifying foot fractures and dislocations.

    PubMed

    Caswell, Fiona; Brown, Craig

    2014-10-01

    As the roles of emergency nurse practitioners expand, more patients with minor injuries are being managed independently by nursing staff. Injuries to the foot and ankle are common among such patients, and X-rays are frequently performed to aid their diagnoses. Some of these fractures and dislocations are subtle and difficult to identify, so practitioners must adopt a structured approach to reading X-rays. This article describes some of these injuries and offers advice, including X-ray illustrations, on how to identify them. PMID:25270819

  1. Hip dysplasia in the skeletally mature patient.

    PubMed

    Goldstein, Rachel Y; Kaye, Ian David; Slover, James; Feldman, David

    2014-01-01

    Abnormal hip development causes one-quarter to one-half of all hip disease. Dysplastic hips typically share characteristic anatomic abnormalities. The dysplastic acetabulum is typically shallow, lateralized, and anteverted with insufficient coverage anteriorly, superiorly, and laterally. The dysplastic proximal femur has a small femoral head with excessive femoral neck anteversion and a short neck with an increased neck shaft angle. These characteristic changes result in intraarticular pathology leading to hip arthritis. A variety of treatment options exist based on the degree of dysplasia and the amount of concomitant hip arthritis. Treatment options include hip arthroscopy, acetabular or femoral osteotomies, hip arthrodesis, and total hip arthroplasty. PMID:25150325

  2. [Intermediate term outcome of of a hip prosthesis revision system].

    PubMed

    Löhr, J F; Schütz, U; Zünd, T; Drobny, T; Munzinger, U

    2001-05-01

    The Zweymüller shaft for uncemented total hip arthroplasty was developed in the early 1970s. Encouraged by the clinical results with this stem, which was mainly used in primary arthroplasty, longer fitting stems were added to the line to accommodate bony defects and to allow for an optimal load transfer from proximal to distal. The principal of the design is to allow an optimal distal fixation while allowing the bone to remodel in the proximal part. This study reports on 89 patients who underwent revision surgery of the hip for mostly aseptic loosening. The results after a median follow-up of 36 months show an increase of the modified Harris hip score from 52 points pre- to 82 points postoperatively. Radiographic subsidence was found in nine cases, with eight having progressed for more then 3 mm. Postoperative complications occurred in 11.2%, with seven dislocations. Open revision became necessary in two cases. The stem reviewed here seems to achieve predictable results in cases where a proximal cone is still present to facilitate load transfer, while at the same time the quadrangular stem provides solid distal fixation and ensures rotary stability. PMID:11417238

  3. Hip Arthroscopy for Challenging Deformities: Global Pincer Femoroacetabular Impingement

    PubMed Central

    Matsuda, Dean K.; Gupta, Nikhil; Hanami, Dylan

    2014-01-01

    Pincer femoroacetabular impingement occurs in focal or global forms, the latter having more generalized and typically more extreme acetabular overcoverage. Severe global deformities are often treated with open surgical dislocation of the hip. Arthroscopic technical challenges relate to difficulties with hip distraction; central-compartment access; and instrument navigation, acetabuloplasty, and chondrolabral surgery of the posterior acetabulum. Techniques addressing these challenges are introduced permitting dual-portal hip arthroscopy with central-compartment access, subtotal acetabuloplasty, and circumferential chondrolabral surgery. The modified midanterior portal in combination with a zone-specific sequence of acetabular rim reduction monitored with fluoroscopic templating enables precision subtotal acetabuloplasty. Guidelines for acetabular rim reduction include the following suggested radiographic endpoints: postoperative center-edge angle of 35°, a neutral posterior wall sign, and an anterior margin ratio of 0.5. Arthroscopic zone-specific chondrophobic rim preparation and circumferential labral reparative and reconstructive techniques and tools permit the arthroscopic treatment of these challenging deformities. PMID:24904760

  4. Modern total hip arthroplasty in patients younger than 21 years.

    PubMed

    Kamath, Atul F; Sheth, Neil P; Hosalkar, Harish H; Babatunde, Oladapo M; Lee, Gwo-Chin; Nelson, Charles L

    2012-03-01

    Total hip arthroplasty (THA) is not commonly performed in adolescents. However, it may be the only option for pain control with continued mobility for advanced disease. We report our experience with modern alternative-bearing THA in patients younger than 21 years. Twenty-one THAs (18 patients) were followed. Preoperative and postoperative Harris hip scores were recorded, and radiographs were reviewed. Average follow-up was 49 months (range, 25-89). Underlying etiology was chemotherapy-induced osteonecrosis (33%), steroid-induced osteonecrosis (29%), sickle cell disease (24%), and chronic dislocation (14%). Articulation bearings were ceramic/ceramic (67%), metal/highly cross-linked polyethylene (29%), and metal resurfacing (5%). Mean age was 18 years (range, 13-20). Harris hip scores improved from 43.6 to 83.6 (P < .001). At final follow-up, there was no radiographic loosening; 1 THA was revised for a cracked ceramic liner. At intermediate-term follow-up, clinical and radiographic results are favorable after alternative-bearing THA in patients younger than 21 years. PMID:21723701

  5. Effect of Hip Angle on Anterior Hip Joint Force during Gait

    PubMed Central

    Lewis, Cara L.; Sahrmann, Shirley A.; Moran, Daniel W.

    2010-01-01

    Anterior hip or groin pain is a common complaint for which people are referred for physical therapy. We have observed that people with anterior hip pain often walk in greater hip extension than people without anterior hip pain, and that the pain is reduced when they walk in less hip extension. Therefore, we investigated anterior hip joint forces which may contribute to anterior hip pain and examined the effect of end range hip extension on the anterior hip joint force during gait. To do this, we used a 6 degree of freedom, 3-dimensional musculoskeletal model to estimate hip joint forces during gait. Within subjects, the maximum anterior hip joint force for gait trials with the most hip extension was compared to the anterior hip joint force for gait trials with the least hip extension. The musculoskeletal model indicated that increasing the maximum end range hip extension when walking results in an increase in the anterior hip joint force when compared to walking in less hip extension. Walking in greater hip extension may result in an increase in the anterior hip joint force, and thereby contribute to anterior hip pain. The findings of this study provide some evidence supporting the use of gait modification to reduce anterior hip force when treating people with anterior hip pain. PMID:20934338

  6. Quantum dislocations in solid Helium-4

    NASA Astrophysics Data System (ADS)

    Aleinikava, Darya

    In this thesis the following problems on properties of solid 4He are considered: (i) the role of long-range interactions in suppression of dislocation roughening at T = 0; (ii) the combined effect of 3He impurities and Peierls potential on shear modulus softening; (iii) the dislocation superclimb and its connection to the phenomenon of "giant isochoric compressibility"; (iv) non-linear dislocation response to the applied stress and stress-induces dislocation roughening as a I-order phase transition in 1D at finite temperature. First we investigate the effect of long-range interactions on the state of edge dislocation at T = 0. Such interactions are induced by elastic forces of the solid. We found that quantum roughening transition of a dislocation at T = 0 is completely suppressed by arbitrarily small long-range interactions between kinks. A heuristic argument is presented and the result has been verified by numerical Monte-Carlo simulations using Worm Algorithm in J-current model. It was shown that the Peierls potential plays a crucial role in explaining the elastic properties of dislocations, namely shear modulus softening phenomenon. The crossover from T = 0 to finite temperatures leads to intrinsic softening of the shear modulus and is solely controlled by kink typical energy. It was demonstrated that the mechanism, involving only the binding of 3He impurities to the dislocations, requires an unrealistically high concentrations of defects (or impurities) in order to explain the shear modulus phenomenon and therefore an inclusion of Peierls potential in consideration is required. Superclimbing dislocations, that is the edge dislocations with the superfluidity along the core, were investigated. The theoretical prediction that superclimb is responsible for the phenomenon of "giant isochoric compressibility" was confirmed by Monte-Carlo simulations. It was demonstrated that the isochoric compressibility is suppressed at low temperatures. The dependence of

  7. [Complications after hip osteotomy].

    PubMed

    Renner, L; Perka, C; Zahn, R

    2014-01-01

    Complex deformities of the acetabulum are one of the most common reasons for secondary pelvic osteoarthritis. One option of treatment is osteotomy of the acetabulum close to the joint. The correction of the spatially reduced roof of the femoral head resulting from pelvic dysplasia can minimize the risk of developing secondary osteoarthritis or reduce the progression of an already existing osteoarthritis. The Ganz periacetabular osteotomy (PAO) and Tönnis triple osteotomy procedures are the predominant methods used to correct hip dysplasia in adolescents. Both are complex procedures which bear specific risks and complications, thus requiring very experienced surgeons. PMID:24356819

  8. Sexual Activity after Total Hip Replacement in Korean Patients: How They Do, What They Want, and How to Improve

    PubMed Central

    Yoon, Byung-Ho; Lee, Kyung-Hag; Noh, Serae; Ha, Yong-Chan; Koo, Kyung-Hoi

    2013-01-01

    Background Concerns of patients on sexual activity after total hip arthroplasty have not been well studied in Asian patients. This study aimed to determine the following: (1) what are the concerns of patients related to sexual activity after total hip arthroplasty? (2) what are the changes in sexual activity after total hip replacement in Korean patients? Methods Details of sexual activity and concerns were obtained using a questionnaire designed specifically for the study. The questionnaire was administered to 64 patients in a face-to-face interview at an outpatient clinic. Results Preoperatively, 53.1% of patients experienced difficulties, primarily due to hip pathology and limitations of motion. The median time to the resumption of sexual activity was 3 months postoperatively, and most patients had no increase in the frequency of sexual activity after the total hip replacement. In 39.1% of patients were seen having difficulties with leg positioning following total hip replacement, and they were likely to change coital positions. The most common concern regarding sexual activity of patients was the fear of dislocation. Furthermore, patients with a higher stress level had lower satisfaction rates. Most patients were unable to obtain information on sexual activity following the total hip arthroplasty, and they did not consult with a physician due to the private nature of the topic. Conclusions Dislocation was the most common concern of patients during sexual activity following a total hip arthroplasty, and a higher stress level was found to be associated with a lower satisfaction rate. Because most patients were unprepared to consult a physician, the provision of appropriate information before a consultation might be beneficial. PMID:24340146

  9. Hip-Hop Education Resources

    ERIC Educational Resources Information Center

    Hall, Marcella Runell

    2009-01-01

    Hip-hop music and culture are often cited as being public pedagogy, meaning the music itself has intrinsic educational value. Non-profit organizations and individual educators have graciously taken the lead in utilizing hip-hop to educate. As the academy continues to debate its effectiveness, teachers and community organizers are moving forward.…

  10. Ultrasound-Guided Hip Procedures.

    PubMed

    Payne, Jeffrey M

    2016-08-01

    This article describes the techniques for performing ultrasound-guided procedures in the hip region, including intra-articular hip injection, iliopsoas bursa injection, greater trochanter bursa injection, ischial bursa injection, and piriformis muscle injection. The common indications, pitfalls, accuracy, and efficacy of these procedures are also addressed. PMID:27468669

  11. Total hip arthroplasty (S-ROM stem) and subtrochanteric osteotomy for Crowe type IV developmental dysplasia of the hip

    PubMed Central

    Li, Liangtao; Yu, Mingyang; Yang, Chen; Gu, Guishan

    2016-01-01

    Background: Developmental dysplasia of the hip (DDH) in adults with severe pain and disability is best treated by total hip arthroplasty (THA). The purpose of this study was to retrospectively evaluate the outcomes of subtrochanteric shortening osteotomy combined with THA using S-ROM stem for those severe patients with a special focus on the effect of two shapes in the subtrochanteric osteotomy ends: Oblique and transverse. Materials and Methods: Twenty one cases with mean age of 43.6 years who met inclusion criteria and were operated between February 2007 and February 2012 were included in the study. Those cases had been divided into two groups (oblique vs. transverse) and all records between the two groups were analyzed. Results: The Harris hip score significantly improved from 30.6 (range 18–59) preoperatively to 91.2 (range 87–98) postoperatively by the latest followup. Complications including one deep venous thrombosis, one intraoperative fracture of femur and two dislocations occurred while they were addressed properly afterward. The oblique group showed significant advantages in operative time, union time and additional fixation in comparison with the transverse group. Conclusions: In the primary THA for the treatment of irreducible DDH, subtrochanteric oblique osteotomy combined with the freely-rotatable S-ROM stem provided favorable short term outcomes by affording both morphological and functional advantages. PMID:27053810

  12. Dislocated interests and climate change

    NASA Astrophysics Data System (ADS)

    Davis, Steven J.; Diffenbaugh, Noah

    2016-06-01

    The predicted effects of climate change on surface temperatures are now emergent and quantifiable. The recent letter by Hansen and Sato (2016 Environ. Res. Lett. 11 034009) adds to a growing number of studies showing that warming over the past four decades has shifted the distribution of temperatures higher almost everywhere, with the largest relative effects on summer temperatures in developing regions such as Africa, South America, southeast Asia, and the Middle East (e.g., Diffenbaugh and Scherer 2011 Clim. Change 107 615–24 Anderson 2011 Clim. Change 108 581; Mahlstein et al 2012 Geophys. Res. Lett. 39 L21711). Hansen and Sato emphasize that although these regions are warming disproportionately, their role in causing climate change—measured by cumulative historical CO2 emissions produced—is small compared to the US and Europe, where the relative change in temperatures has been less. This spatial and temporal mismatch of climate change impacts and the burning of fossil fuels is a critical dislocation of interests that, as the authors note, has ‘substantial implications for global energy and climate policies.’ Here, we place Hansen and Sato’s ‘national responsibilities’ into a broader conceptual framework of problematically dislocated interests, and briefly discuss the related challenges for global climate mitigation efforts.

  13. Dislocation-Free Czochralski Silicon Crystal Growth without the Dislocation-Elimination-Necking Process

    NASA Astrophysics Data System (ADS)

    Hoshikawa, Keigo; Huang, Xinming; Taishi, Toshinori; Kajigaya, Tomio; Iino, Takayuki

    1999-12-01

    Dislocation-free silicon crystals have been grown successfully from heavily-boron-doped silicon melts by the Czochralski method without the dislocation-elimination-necking process (Dash neck). A dislocation-free silicon seed of <001> orientation with a boron concentration of about 4×1019 atoms/cm3 was used to grow a silicon crystal with the same boron concentration. No dislocation was generated in the seed during the dipping process, and no misfit dislocation occurred in the grown crystal. These results show that shoulder and body growth can be started immediately after the seeding process.

  14. A rare variant of knee dislocation

    PubMed Central

    HUSSIN, P.; MAWARDI, M.; AB HALIM, A.H.

    2016-01-01

    Knee dislocation is a rare injury. It represents less than 0.2% of orthopaedic injuries. This case reports a rare form of knee dislocation caused by the impact of a high-energy trauma. In these cases the appropriate assessment and management is needed to ensure that patient receives the proper treatment. PMID:27381692

  15. Dislocation generation during early stage sintering.

    NASA Technical Reports Server (NTRS)

    Sheehan, J. E.; Lenel, F. V.; Ansell, G. S.

    1973-01-01

    Discussion of the effects of capillarity-induced stresses on dislocations during early stage sintering. A special version of Hirth's (1963) theoretical calculation procedures modified to describe dislocation nucleation on planes meeting the sintering body's neck surface obliquely is shown to predict plastic flow at stress levels know to exist between micron size metal particles in the early stages of sintering.

  16. Intermittent dislocation flow in viscoplastic deformation.

    PubMed

    Miguel, M C; Vespignani, A; Zapperi, S; Weiss, J; Grasso, J R

    2001-04-01

    The viscoplastic deformation (creep) of crystalline materials under constant stress involves the motion of a large number of interacting dislocations. Analytical methods and sophisticated 'dislocation dynamics' simulations have proved very effective in the study of dislocation patterning, and have led to macroscopic constitutive laws of plastic deformation. Yet, a statistical analysis of the dynamics of an assembly of interacting dislocations has not hitherto been performed. Here we report acoustic emission measurements on stressed ice single crystals, the results of which indicate that dislocations move in a scale-free intermittent fashion. This result is confirmed by numerical simulations of a model of interacting dislocations that successfully reproduces the main features of the experiment. We find that dislocations generate a slowly evolving configuration landscape which coexists with rapid collective rearrangements. These rearrangements involve a comparatively small fraction of the dislocations and lead to an intermittent behaviour of the net plastic response. This basic dynamical picture appears to be a generic feature in the deformation of many other materials. Moreover, it should provide a framework for discussing fundamental aspects of plasticity that goes beyond standard mean-field approaches that see plastic deformation as a smooth laminar flow. PMID:11287948

  17. Microscopically derived free energy of dislocations

    NASA Astrophysics Data System (ADS)

    Kooiman, M.; Hütter, M.; Geers, M. G. D.

    2015-05-01

    The dynamics of large amounts of dislocations is the governing mechanism in metal plasticity. The free energy of a continuous dislocation density profile plays a crucial role in the description of the dynamics of dislocations, as free energy derivatives act as the driving forces of dislocation dynamics. In this contribution, an explicit expression for the free energy of straight and parallel dislocations with different Burgers vectors is derived. The free energy is determined using systematic coarse-graining techniques from statistical mechanics. The starting point of the derivation is the grand-canonical partition function derived in an earlier work, in which we accounted for the finite system size, discrete glide planes and multiple slip systems. In this paper, the explicit free energy functional of the dislocation density is calculated and has, to the best of our knowledge, not been derived before in the present form. The free energy consists of a mean-field elastic contribution and a local defect energy, that can be split into a statistical and a many-body contribution. These depend on the density of positive and negative dislocations on each slip system separately, instead of GND-based quantities only. Consequently, a crystal plasticity model based on the here obtained free energy, should account for both statistically stored and geometrically necessary dislocations.

  18. Community College Adjustment among Dislocated Workers

    ERIC Educational Resources Information Center

    Schwitzer, Alan M.; Duggan, Molly H.; Laughlin, Janet T.; Walker, Martha A.

    2011-01-01

    Community colleges often are catalysts for economic and workforce development in localities with high unemployment or large numbers of dislocated workers. Increasingly, dislocated workers--individuals who have experienced job loss due to occupational closings, reduced workforces, or severe local economic downturns--are enrolling in educational and…

  19. Geometric approach to dislocation and disclination theory

    SciTech Connect

    Nesterov, A.I.; Ovchinnikov, S.G.

    1988-05-01

    Cartan structure equations are used to create a four-dimensional geometric description of dislocations in continuum theory. It is shown that the dislocation distribution is determined by the torsion tensor, while the disclination distribution is determined by the curvature tensor. An analogy to electrodynamics is offered.

  20. Statistics of dislocation pinning at localized obstacles

    SciTech Connect

    Dutta, A.; Bhattacharya, M. Barat, P.

    2014-10-14

    Pinning of dislocations at nanosized obstacles like precipitates, voids, and bubbles is a crucial mechanism in the context of phenomena like hardening and creep. The interaction between such an obstacle and a dislocation is often studied at fundamental level by means of analytical tools, atomistic simulations, and finite element methods. Nevertheless, the information extracted from such studies cannot be utilized to its maximum extent on account of insufficient information about the underlying statistics of this process comprising a large number of dislocations and obstacles in a system. Here, we propose a new statistical approach, where the statistics of pinning of dislocations by idealized spherical obstacles is explored by taking into account the generalized size-distribution of the obstacles along with the dislocation density within a three-dimensional framework. Starting with a minimal set of material parameters, the framework employs the method of geometrical statistics with a few simple assumptions compatible with the real physical scenario. The application of this approach, in combination with the knowledge of fundamental dislocation-obstacle interactions, has successfully been demonstrated for dislocation pinning at nanovoids in neutron irradiated type 316-stainless steel in regard to the non-conservative motion of dislocations. An interesting phenomenon of transition from rare pinning to multiple pinning regimes with increasing irradiation temperature is revealed.

  1. Statistics of dislocation pinning at localized obstacles

    NASA Astrophysics Data System (ADS)

    Dutta, A.; Bhattacharya, M.; Barat, P.

    2014-10-01

    Pinning of dislocations at nanosized obstacles like precipitates, voids, and bubbles is a crucial mechanism in the context of phenomena like hardening and creep. The interaction between such an obstacle and a dislocation is often studied at fundamental level by means of analytical tools, atomistic simulations, and finite element methods. Nevertheless, the information extracted from such studies cannot be utilized to its maximum extent on account of insufficient information about the underlying statistics of this process comprising a large number of dislocations and obstacles in a system. Here, we propose a new statistical approach, where the statistics of pinning of dislocations by idealized spherical obstacles is explored by taking into account the generalized size-distribution of the obstacles along with the dislocation density within a three-dimensional framework. Starting with a minimal set of material parameters, the framework employs the method of geometrical statistics with a few simple assumptions compatible with the real physical scenario. The application of this approach, in combination with the knowledge of fundamental dislocation-obstacle interactions, has successfully been demonstrated for dislocation pinning at nanovoids in neutron irradiated type 316-stainless steel in regard to the non-conservative motion of dislocations. An interesting phenomenon of transition from rare pinning to multiple pinning regimes with increasing irradiation temperature is revealed.

  2. Dislocation patterning in a two-dimensional continuum theory of dislocations

    NASA Astrophysics Data System (ADS)

    Groma, István; Zaiser, Michael; Ispánovity, Péter Dusán

    2016-06-01

    Understanding the spontaneous emergence of dislocation patterns during plastic deformation is a long standing challenge in dislocation theory. During the past decades several phenomenological continuum models of dislocation patterning were proposed, but few of them (if any) are derived from microscopic considerations through systematic and controlled averaging procedures. In this paper we present a two-dimensional continuum theory that is obtained by systematic averaging of the equations of motion of discrete dislocations. It is shown that in the evolution equations of the dislocation densities diffusionlike terms neglected in earlier considerations play a crucial role in the length scale selection of the dislocation density fluctuations. It is also shown that the formulated continuum theory can be derived from an averaged energy functional using the framework of phase field theories. However, in order to account for the flow stress one has in that case to introduce a nontrivial dislocation mobility function, which proves to be crucial for the instability leading to patterning.

  3. Hip Abduction Can Prevent Posterior Edge Loading of Hip Replacements

    PubMed Central

    van Arkel, Richard J; Modenese, Luca; Phillips, Andrew TM; Jeffers, Jonathan RT

    2013-01-01

    Edge loading causes clinical problems for hard-on-hard hip replacements, and edge loading wear scars are present on the majority of retrieved components. We asked the question: are the lines of action of hip joint muscles such that edge loading can occur in a well-designed, well-positioned acetabular cup? A musculoskeletal model, based on cadaveric lower limb geometry, was used to calculate for each muscle, in every position within the complete range of motion, whether its contraction would safely pull the femoral head into the cup or contribute to edge loading. The results show that all the muscles that insert into the distal femur, patella, or tibia could cause edge loading of a well-positioned cup when the hip is in deep flexion. Patients frequently use distally inserting muscles for movements requiring deep hip flexion, such as sit-to-stand. Importantly, the results, which are supported by in vivo data and clinical findings, also show that risk of edge loading is dramatically reduced by combining deep hip flexion with hip abduction. Patients, including those with sub-optimally positioned cups, may be able to reduce the prevalence of edge loading by rising from chairs or stooping with the hip abducted. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1172–1179, 2013. PMID:23575923

  4. Alumina-on-alumina total hip prostheses in patients 40 years of age or younger.

    PubMed

    Bizot, P; Banallec, L; Sedel, L; Nizard, R

    2000-10-01

    To avoid the consequences of polyethylene wear in a high-risk population, 128 alumina-on-alumina total hip arthroplasties have been done in 104 consecutive patients. The maximum age of patients was 40 years. The main preoperative diagnoses were osteonecrosis and sequellae of congenital hip dislocation (71% of the hips). The same titanium alloy cemented stem was implanted in all of the hips. Four types of alumina acetabular component fixations were used: a cemented plain alumina socket (41 hips), a screw-in ring with an alumina insert (22 hips), a press-fit plain alumina socket (32 hips), and a press-fit titanium metal back with an alumina insert (33 hips). Eight patients (11 hips) died during the followup period. Sixteen revisions have been documented, 12 for acetabular aseptic loosening, three for bipolar loosening (two of which were septic), and one for unexplained pain. Eighty-eight hips in 74 patients have been followed up radiologically for 2 to 22 years. Wear was unmeasurable. Four additional sockets showed definite migration. The respective survival rates after 7 years were 94.1% for the cemented cup, 88.8% for the screw-in ring, 95.1% for cementless press-fit plain alumina socket and 94.3% for the metal-back press-fit component. The 10-year survival rate was 90.4% for the cemented socket and 88.8% for the screw-in ring. The 15-year survival rate was 78.9% for the cemented socket. Grafting was the only prognostic factor, with a survival rate of 62.6% after 10 years for the hips with a bone graft and of 90.1% for hips without a graft. The alumina-on-alumina bearing surfaces seem to be a valuable alternative to the standard metal-on-polyethylene system for young patients. However, an improvement in socket fixation is required to lengthen the life span of the prosthesis to match the life expectancy of this demanding population. PMID:11039794

  5. Dislocation core in GaN

    SciTech Connect

    Liliental-Weber, Zuzanna; Jasinski, Jacek B.; Washburn, Jack; O'Keefe, Michael A.

    2002-02-20

    Light emitting diodes and blue laser diodes grown on GaN have been demonstrated despite six orders of magnitude higher dislocation density than that for III-V arsenide and phosphide diodes. Understanding and determination of dislocation cores in GaN is crucial since both theoretical and experimental work are somewhat contradictory. Transmission Electron Microscopy (TEM) has been applied to study the layers grown by hydride vapor-phase epitaxy (HVPE) and molecular beam epitaxy (MBE) (under Ga rich conditions) in plan-view and cross-section samples. This study suggests that despite the fact that voids are formed along the dislocation line in HVPE material, the dislocations have closed cores. Similar results of closed core are obtained for the screw dislocation in the MBE material, confirming earlier studies.

  6. BILATERAL ANTERIOR GLENOHUMERAL DISLOCATION: CLINICAL CASE

    PubMed Central

    Silva, Luís Pires; Sousa, Cristina Varino; Rodrigues, Elisa; Alpoim, Bruno; Leal, Miguel

    2015-01-01

    Bilateral anterior glenohumeral dislocation is a rare occurrence. We present a case of bilateral anterior glenohumeral dislocation caused by a fall. The interest in publishing this case is that this is a clinical rarity with few cases reported in the literature. An 89-year-old female patient was brought to the emergency department after a fall, complaining of intense pain in both shoulders and inability to move them. Objective examination showed clinical signs giving the suspicion of bilateral anterior glenohumeral dislocation, which was confirmed by x-ray imaging. Both dislocations were successfully reduced in the emergency department using the modified Milch technique. When a synchronous and symmetrical force has acted on both shoulders and these are painful with significant functional limitation, the suspicion of bilateral glenohumeral dislocation is a differential diagnosis to be considered, even though it is rare. PMID:27047826

  7. Distribution of dislocations in nanostructured bainite

    SciTech Connect

    Cornide, J; Miyamoto, G; Caballero, Francesca G.; Furuhara, T; Miller, Michael K; Garcia-Mateo, C.

    2011-01-01

    The dislocation density in ferrite and austenite of a bainitic microstructure obtained by transformation at very low temperature (300 C) has been determined using transmission electron microscopy. Observations revealed that bainitic ferrite plates consist of two distinctive regions with different substructures. A central region in the ferrite plate is observed with dislocations that may result from lattice-invariant deformation at the earlier stage of bainite growth. As plastic deformation occurs in the surrounding austenite to accommodate the transformation strain as growth progresses, the Ferrite/Austenite interface has also a very distinctive dislocation profile. In addition, atom-probe tomography suggested that dislocation tangles observed in the vicinity of the ferrite/austenite interface might trap higher amount of carbon than single dislocations inside the bainitic ferrite plate.

  8. Arthroscopic Treatment of Perilunate Dislocations and Fracture Dislocations

    PubMed Central

    Kim, Jong Pil; Lee, Jae Sung; Park, Min Jong

    2015-01-01

    Background The key to a successful result in the treatment of perilunate dislocations (PLDs) and fracture-dislocations (PLFDs) is the restoration of normal alignment of the carpal bones, followed by stable maintenance until healing. This article aimed to assess whether arthroscopic techniques are a reliable surgical option for the treatment of this challenging injury. Materials and Methods Twenty patients with an acute PLD or PLFD were treated by an arthroscopic technique. They were retrospectively reviewed at an average follow-up of 31.2 months (range 18–61 months). Functional outcomes were assessed with the Modified Mayo Wrist Score (MMWS), Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire, and Patient-Rated Wrist Evaluation (PRWE) score as well as radiographic evaluations. Description of Technique Arthroscopic reduction and percutaneous fixation was performed to the scapholunate and lunotriquetral intervals using Kirschner wires (K-wires) as joysticks as well as to the scaphoid using a cannulated headless screw for transscaphoid-type injuries. The K-wires were removed at 10 weeks postoperation. Results Overall functional outcomes according to the MMWS were rated as excellent in three patients, good in eight, fair in seven, and poor in two. The mean DASH score was 18, and the mean PRWE score was 30. On the basis of radiographic parameters, reduction obtained at the operation was maintained within normal ranges in 15 patients. No patient had developed arthritis by the last follow-up. Conclusions The medium-term results show that arthroscopic treatment can provide proper restoration and stable fixation of carpal alignment and results in satisfactory functional and radiologic outcomes for acute perilunate injuries. Level of Evidence Level IV. PMID:25945291

  9. Surgical Treatment of Synovial Osteochondromatosis of the Hip Using a Modified-Hardinge Approach with a Z-Shaped Capsular Incision

    PubMed Central

    Fukunishi, Shigeo; Nishio, Shoji; Fujihara, Yuki; Fukui, Tomokazu; Okahisa, Shohei; Yoshiya, Shinichi

    2015-01-01

    Synovial osteochondromatosis of the hip is a rare condition, and the surgical treatment approach for this condition requires complete removal of loose bodies combined with synovectomy. While these, procedures are generally accepted as the optimal treatment method, this is still controversial topic. Recent studies have reported that open surgical procedures remain acceptable for synovial osteochondromatosis of the hip. These procedures include the dislocation of the femoral head, and complications such as femoral head necrosis and bursitis or great trochanter non-union due to trochanteric osteotomy have been reported. The present study reports a modified technique for surgical dislocation through a Z-shaped capsular incision without trochanteric flip osteotomy for the treatment of synovial osteochondromatosis of the hip. PMID:26793291

  10. Surgical Treatment of Synovial Osteochondromatosis of the Hip Using a Modified-Hardinge Approach with a Z-Shaped Capsular Incision.

    PubMed

    Takeda, Yu; Fukunishi, Shigeo; Nishio, Shoji; Fujihara, Yuki; Fukui, Tomokazu; Okahisa, Shohei; Yoshiya, Shinichi

    2015-12-28

    Synovial osteochondromatosis of the hip is a rare condition, and the surgical treatment approach for this condition requires complete removal of loose bodies combined with synovectomy. While these, procedures are generally accepted as the optimal treatment method, this is still controversial topic. Recent studies have reported that open surgical procedures remain acceptable for synovial osteochondromatosis of the hip. These procedures include the dislocation of the femoral head, and complications such as femoral head necrosis and bursitis or great trochanter non-union due to trochanteric osteotomy have been reported. The present study reports a modified technique for surgical dislocation through a Z-shaped capsular incision without trochanteric flip osteotomy for the treatment of synovial osteochondromatosis of the hip. PMID:26793291

  11. 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... 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...

  12. 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...

  13. 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... 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...

  14. 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... 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...

  15. 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... 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...

  16. Recurrent Dislocation of the Patella

    PubMed Central

    Benítez, Gustavo

    2015-01-01

    Purpose: To evaluate results of medial patellofemoral ligament (MPFL) reconstruction associated with lateral release and advancement of vastus medialis in recurrent dislocation of the patella. Methods: We retrospectively evaluated 11 patients with a mean follow-up of 19 months. Mean age was 23, mainly women. We did MPFL reconstruction with semitendinosus or gracilis tendon depending on BMI, associated with advancement of vastus medialis and lateral release. Results: Mean Kujala score improved from 46,54 pts. preoperative to 88,36 postoperative. Our main complication was 1 patient with rigid knee, who required movilization under anesthesia and arthroscopic arthrolisis to improve her outcome. Conclusion: The combination of this techniques are a good alternative to treat patients with recurrent patella disclocation, with good short and mid-term results. Biomechanic intra and postop complications of MPFL reconstruction are related to patellar fixation, anatomic positioning of femoral tunnel and knee position of the graft fixation.

  17. Anterior hip pain.

    PubMed

    O'Kane, J W

    1999-10-15

    Anterior hip pain is a common complaint with many possible causes. Apophyseal avulsion and slipped capital femoral epiphysis should not be overlooked in adolescents. Muscle and tendon strains are common in adults. Subsequent to accurate diagnosis, strains should improve with rest and directed conservative treatment. Osteoarthritis, which is diagnosed radiographically, generally occurs in middle-aged and older adults. Arthritis in younger adults should prompt consideration of an inflammatory cause. A possible femoral neck stress fracture should be evaluated urgently to prevent the potentially significant complications associated with displacement. Patients with osteitis pubis should be educated about the natural history of the condition and should undergo physical therapy to correct abnormal pelvic mechanics. "Sports hernias," nerve entrapments and labral pathologic conditions should be considered in athletic adults with characteristic presentations and chronic symptoms. Surgical intervention may allow resumption of pain-free athletic activity. PMID:10537384

  18. Continuum framework for dislocation structure, energy and dynamics of dislocation arrays and low angle grain boundaries

    NASA Astrophysics Data System (ADS)

    Zhu, Xiaohong; Xiang, Yang

    2014-09-01

    We present a continuum framework for dislocation structure, energy and dynamics of dislocation arrays and low angle grain boundaries that are allowed to be nonplanar or nonequilibrium. In our continuum framework, we define a dislocation density potential function on the dislocation array surface or grain boundary to describe the orientation dependent continuous distribution of dislocations in a very simple and accurate way. The continuum formulations incorporate both the long-range dislocation interaction and the local dislocation line energy, and are derived from the discrete dislocation model. The continuum framework recovers the classical Read-Shockley energy formula when the long-range elastic fields of the low angle grain boundaries are canceled out. Applications of our continuum framework in this paper are focused on dislocation structures on static planar and nonplanar low angle grain boundaries and misfitting interfaces. We present two methods under our continuum framework for this purpose, including the method based on the Franks formula and the energy minimization method. We show that for any (planar or nonplanar) low angle grain boundary, the Franks formula holds if and only if the long-range stress field in the continuum model is canceled out, and it does not necessarily hold for a total energy minimum dislocation structure.

  19. Evolution, Interaction, and Intrinsic Properties of Dislocations in Intermetallics: Anisotropic 3D Dislocation Dynamics Approach

    SciTech Connect

    Qian Chen

    2008-08-18

    The generation, motion, and interaction of dislocations play key roles during the plastic deformation process of crystalline solids. 3D Dislocation Dynamics has been employed as a mesoscale simulation algorithm to investigate the collective and cooperative behavior of dislocations. Most current research on 3D Dislocation Dynamics is based on the solutions available in the framework of classical isotropic elasticity. However, due to some degree of elastic anisotropy in almost all crystalline solids, it is very necessary to extend 3D Dislocation Dynamics into anisotropic elasticity. In this study, first, the details of efficient and accurate incorporation of the fully anisotropic elasticity into 3D discrete Dislocation Dynamics by numerically evaluating the derivatives of Green's functions are described. Then the intrinsic properties of perfect dislocations, including their stability, their core properties and disassociation characteristics, in newly discovered rare earth-based intermetallics and in conventional intermetallics are investigated, within the framework of fully anisotropic elasticity supplemented with the atomistic information obtained from the ab initio calculations. Moreover, the evolution and interaction of dislocations in these intermetallics as well as the role of solute segregation are presented by utilizing fully anisotropic 3D dislocation dynamics. The results from this work clearly indicate the role and the importance of elastic anisotropy on the evolution of dislocation microstructures, the overall ductility and the hardening behavior in these systems.

  20. Effect of Mg on the Grain Growth and Dislocation Creep of Calcite

    NASA Astrophysics Data System (ADS)

    Xu, L.

    2004-12-01

    We tested the effect of variations in the amount of the solute impurity (Mg) on grain growth and strength of calcite aggregate. Synthetic marbles were produced by hot isostatic pressing mixtures of powders of calcite and dolomite at 850° C and 300 MPa confining pressure for different intervals (2 to 30 hrs). The HIP treatment resulted in homogeneous aggregates of calcite with Mg content from 0.5 to 17 mol%. Stress stepping tests and constant strain rate tests were used to examine the effect of Mg content on the dislocation creep of calcite. The grain growth rate under static conditions was decreased with Mg content from 7 to 17 mol%, indicating perhaps that grain boundary mobility is suppressed by the solute drag effect. In the diffusion creep at stresses below 40 Mpa, the strength of calcite decreases with increasing Mg content owing to the difference in grain size at 800° C and 300 MPa confining pressure. The contribution of dislocation creep increases with increasing stress, and the transition between diffusion and dislocation creep occurs at higher stresses for the samples with higher magnesium content and smaller grain size. The creep data were fit assuming a composite flow law consisting of a linear combination of diffusion and dislocation creep and a single-valued grain size. The best agreement was obtained by using a dislocation creep law with exponential dependence of strain rate on stress (e.g. Peierls law). More evidence from microstructure is needed to identify the dominant deformation mechanism conclusively. Most of the samples were compressed up to strains of 0.25; small recrystallized grains are formed resulting in a bimodal grain size distribution in some of the deformed samples. Preliminary data shows that the recrystallized grain sizes are smaller for Mg-calcite compared with that of pure calcite. This study will help to understand the effect of impurities on grain-growth kinetics and strain weakening in localized shear zones.

  1. Thermodynamic forces in single crystals with dislocations

    NASA Astrophysics Data System (ADS)

    Van Goethem, Nicolas

    2014-06-01

    A simple model for the evolution of macroscopic dislocation regions in a single crystal is presented. This model relies on maximal dissipation principle within Kröner's geometric description of the dislocated crystal. Mathematical methods and tools from shape optimization theory provide equilibrium relations at the dislocation front, similarly to previous work achieved on damage modelling (J Comput Phys 33(16):5010-5044, 2011). The deformation state variable is the incompatible strain as related to the dislocation density tensor by a relation involving the Ricci curvature of the crystal underlying elastic metric. The time evolution of the model variables follows from a novel interpretation of the Einstein-Hilbert flow in terms of dislocation microstructure energy. This flow is interpreted as the dissipation of non-conservative dislocations, due to the climb mechanism, modelled by an average effect of mesoscopic dislocations moving normal to their glide planes by adding or removing points defects. The model equations are a fourth-order tensor parabolic equation involving the operator "incompatibility," here appearing as a tensorial counterpart of the scalar Laplacian. This work encompasses and generalizes results previously announced (C R Acad Sci Paris Ser I 349:923-927, 2011), with in addition a series of physical interpretations to give a meaning to the newly introduced concepts.

  2. Ultrasonic Study of Dislocation Dynamics in Lithium -

    NASA Astrophysics Data System (ADS)

    Han, Myeong-Deok

    1987-09-01

    Experimental studies of dislocation dynamics in LiF single crystals, using ultrasonic techniques combined with dynamic loading, were performed to investigate the time evolution of the plastic deformation process under a short stress pulse at room temperature, and the temperature dependence of the dislocation damping mechanism in the temperature range 25 - 300(DEGREES)K. From the former, the time dependence of the ultrasonic attenuation was understood as resulting from dislocation multiplication followed by the evolution of mobile dislocations to immobile ones under large stress. From the latter, the temperature dependence of the ultrasonic attenuation was interpreted as due to the motion of the dislocation loops overcoming the periodic Peierls potential barrier in a manner analogous to the motion of a thermalized sine-Gordon chain under a small stress. The Peierls stress obtained from the experimental results by application of Seeger's relaxation model with exponential dislocation length distribution was 4.26MPa, which is consistent with the lowest stress for the linear relation between the dislocation velocity and stress observed by Flinn and Tinder.

  3. Primary total hip replacement versus hip resurfacing - hospital considerations.

    PubMed

    Ward, William G; Carter, Christina J; Barone, Marisa; Jinnah, Riyaz

    2011-01-01

    Multiple factors regarding surgical procedures and patient selection affect hospital staffing needs as well as hospital revenues. In order to better understand the potential impact on hospitals that hip arthroplasty device selection (standard total hip arthroplasty vs. resurfacing) creates, a review of all primary hip arthroplasties performed at one institution was designed to identify factors that impacted hospital staffing needs and revenue generation. All primary hip arthroplasties undertaken over three fiscal years (2008 to 2010) were reviewed, utilizing only hospital business office data and medical records data that had been previously extracted prior for billing purposes. Analysis confirmed differing demographics for two hip arthroplasty populations, with the resurfacing patients (compared to the conventional total hip arthroplasty population) consisting of younger patients (mean age, 50 vs. 61 years), who were more often male (75% vs. 45%), were more likely to have osteoarthritis as their primary diagnosis (83 vs. 67%) and were more often covered by managed care or commercial insurance (83 vs. 34%). They also had shorter hospital stays (mean length of stay, 2.3 vs. 4.1 days) and consequently provided a more favorable financial revenue stream to the hospital on a per patient basis. Several trends appeared during the study periods. There was a steady increase in all procedures in all groups except for the resurfacings, which decreased 26% in males and 53% in females between 2009 and 2010. Differences were observed in the demographics of patients presenting for resurfacing, compared to those presenting for conventional total hip arthroplasty. In addition to the revenue stream considerations, institutions undertaking a resurfacing program must commit the resources and planning in order to rehabilitate these patients more expeditiously than is usually required with conventional hip arthroplasty patients. PMID:22035493

  4. Association of hip pain with radiographic evidence of hip osteoarthritis: diagnostic test study

    PubMed Central

    Nevitt, Michael C; Niu, Jingbo; Clancy, Mary M; Lane, Nancy E; Link, Thomas M; Vlad, Steven; Tolstykh, Irina; Jungmann, Pia M.; Felson, David T; Guermazi, Ali

    2015-01-01

    Study question Is there concordance between hip pain and radiographic hip osteoarthritis? Methods In this diagnostic test study, pelvic radiographs were assessed for hip osteoarthritis in two cohorts: the Framingham Osteoarthritis Study (community of Framingham, Massachusetts) and the Osteoarthritis Initiative (a multicenter longitudinal cohort study of osteoarthritis in the United States). Using visual representation of the hip joint, participants reported whether they had hip pain on most days and the location of the pain: anterior, groin, lateral, buttocks, or low back. In the Framingham study, participants with hip pain were also examined for hip pain with internal rotation. The authors analysed the agreement between radiographic hip osteoarthritis and hip pain, and for those with hip pain suggestive of hip osteoarthritis they calculated the sensitivity, specificity, positive predictive value, and negative predictive value of radiographs as the diagnostic test. Study answer and limitations In the Framingham study (n=946), only 15.6% of hips in patients with frequent hip pain showed radiographic evidence of hip osteoarthritis, and 20.7% of hips with radiographic hip osteoarthritis were frequently painful. The sensitivity of radiographic hip osteoarthritis for hip pain localised to the groin was 36.7%, specificity 90.5%, positive predictive value 6.0%, and negative predictive value 98.9%. Results did not differ much for hip pain at other locations or for painful internal rotation. In the Osteoarthritis Initiative study (n=4366), only 9.1% of hips in patients with frequent pain showed radiographic hip osteoarthritis, and 23.8% of hips with radiographic hip osteoarthritis were frequently painful. The sensitivity of definite radiographic hip osteoarthritis for hip pain localised to the groin was 16.5%, specificity 94.0%, positive predictive value 7.1%, and negative predictive value 97.6%. Results also did not differ much for hip pain at other locations. What this

  5. Hip Surgery Candidates: A Comparative Study of Hip Osteoarthritis and Prior Hip Fracture Patient Characteristics

    PubMed Central

    Marks, Ray

    2008-01-01

    Aim: To assess similarities and differences in patient-related characteristics before and after surgery for painful disabling hip osteoarthritis among elderly subgroups with and without a trauma history. Method: First, a cohort of 1000 hospitalized patients were assessed for trends in: perceived duration of the condition, pain intensity, functional performance ability, walking distance, body mass, and comorbidity characteristics among other factors. Then, the most salient of these patient-related characteristics were compared between 42 cases of hip osteoarthritis without a trauma history and 42 cases with a trauma history matched for age and gender, using medical records and standard data recording and analysis procedures. Results: Hip osteoarthritis cases with a prior hip fracture history had a longer duration of disability, and were more impaired functionally before surgery (p < 0.05) than those with no such history. They also had lower leg muscle strength and used more assistive devices. Conclusion: Patients undergoing hip replacement surgery for painful hip osteoarthritis who have a hip fracture history are likely to be more impaired and disabled than those with no such history. PMID:19478931

  6. Catastrophic Failure of the Acetabular Polyethylene Liner in Ceramic-on-Polyethylene Total Hip Arthroplasty

    PubMed Central

    Manzano, Givenchy; Levin, Rayna A. C.; Mayor, Michael B.; Schwarzkopf, Ran

    2014-01-01

    Introduction: Catastrophic polyethylene failure is a rare complication of ceramic-on-polyethylene total hip arthroplasty due to the favorable tribological characteristics of ceramic. Failure of the polyethylene liner can be disastrous, increasing periprosthetic osteolysis, metallosis, and risk of dislocation. Complications associated with ceramic-on-polyethylene articulations have been studied extensively, however, only few reports have described its catastrophic wear. We report such a case of complete wear of the acetabular liner in a ceramic-on-polyethylene prosthesis in a 57-year adult male. Case Report: A 57-year adult male with a history of bilateral total hip arthroplasty presented to our institution with bilateral hip pain worst on the right. Range of motion was limited by pain on the right hip at the extremes of motion. Radiographs revealed severe osteolysis, heterotopic ossification, complete wear of the acetabular liner, bony impingement of the femoral greater trochanter on the acetabular rim and superior migration of the femoral head. All findings were confirmed intraoperatively. Revision of the acetabular components was performed, which successfully alleviated the patient’s symptoms. Conclusion: Failure of the ceramic-on-polyethylene liner in our patient is due to the use of a non-cross linked polyethylene liner, a highly active lifestyle, and poor follow up. Arthroplasty surgeons should be aware of this complication especially in highly active patients with a conventional polyethylene liner and chronic hip pain. PMID:27298960

  7. Effect of HIP Temperature on Microstructure and Creep Property of FGH95 Alloy

    NASA Astrophysics Data System (ADS)

    Xie, Jun; Tian, Su-Gui; Zhou, Xiao-Ming

    2012-02-01

    By means of hot isostatic pressing (HIP) treatment, microstructure observation and creep properties measurement, the effects of the HIP temperatures on the microstructure and creep properties of FGH95 nickel-base superalloy are investigated. The results show that, when the HIP temperature is lower than solubility of γ' phase, the coarser γ' phase is precipitated in the previous particle boundary (PPB) regions, and the quantity and size of the coarser γ' phase which is distributed in the regions decrease as the HIP temperature increases. No feature of the grain growing up is detected after the alloy is solution treated at 1140 °C. Moreover, there are a few of carbide particles distributing along the grain boundary and in the grain. After HIP treated at 1180 °C and fully heat treated, coarser γ' phase is dissolved in the alloy, and the depleted zone of the fine γ' phase has disappeared. In addition, the grains grow up obviously in the alloy, and the γ' phase and fine carbide particles are dispersedly precipitated in the grains and along boundaries, which can enhance the creep resistance of the alloy. The deformation mechanisms of the alloy are that the dislocations slip in the matrix or shear into γ' phase during creep.

  8. MR Imaging in Postreduction Assessment of Developmental Dysplasia of the Hip: Goals and Obstacles.

    PubMed

    Rosenbaum, Daniel G; Servaes, Sabah; Bogner, Eric A; Jaramillo, Diego; Mintz, Douglas N

    2016-01-01

    Developmental dysplasia of the hip is a spectrum disorder of hip development that ranges in severity from abnormal acetabular morphology to complete hip dislocation. While treatment with a Pavlik harness is highly effective in infants younger than 6 months, older infants and children and those with orthotic failure often warrant surgical reduction and placement of a spica cast, which limits subsequent imaging evaluation. Magnetic resonance (MR) imaging has been described in the evaluation of the adequacy of hip reduction for more than 2 decades, but the practice is still not widespread and is performed routinely at relatively few centers. MR imaging is a robust tool for outcome assessment after hip reduction and placement of a spica cast, facilitating multiplanar confirmation of concentric reduction independent of an ossific nucleus or orthopedic hardware. Excellent image contrast of soft tissues allows identification of obstacles to concentric reduction, which may be extra-articular or intra-articular. Extra-articular obstacles include tightening of the adductor muscles and tightening of the iliopsoas tendon with constriction of the joint capsule. Intra-articular obstacles include limbus formation, labral inversion, an enlarged pulvinar, and hypertrophy of the ligamentum teres and/or the transverse acetabular ligament. Intravenous contrast material administration may demonstrate altered epiphyseal blood flow and help identify patients at risk for early ischemia. Imaging technique and image interpretation can be optimized to facilitate the performance of postreduction MR imaging studies where they may be of benefit. (©)RSNA, 2016. PMID:27035836

  9. Monteggia fracture-dislocations: A Historical Review

    PubMed Central

    Rehim, Shady A.; Maynard, Mallory A.; Sebastin, Sandeep J.; Chung, Kevin C.

    2014-01-01

    The eponym Monteggia fracture-dislocation originally referred to a fracture of the shaft of the ulna accompanied by anterior dislocation of the radial head that was described by Giovanni Battista Monteggia of Italy in 1814. Subsequently, a further classification system based on the direction of the radial head dislocation and associated fractures of the radius and ulna was proposed by Jose Luis Bado of Uruguay in 1958. This article investigates the evolution of treatment, classification, and outcomes of the Monteggia injury and sheds light on the lives and contributions of Monteggia and Bado. PMID:24792923

  10. Dislocation punching from ceramic/metal interfaces

    SciTech Connect

    Taya, M. ); Mori, T. . Dept. of Materials Science and Engineering)

    1994-07-01

    Relaxation of misfit strains at interfaces between two different materials by dislocation punching is studied analytically by focusing on two types of interfaces: planar and nonplanar. As an example of planar type interface, the case of metal coating/ceramic substrate system is studied while ceramic filler/metal matrix composite system is examined as an example of a nonplanar interface. Based on the present analytical model, the condition for dislocation punching for each interface is established. Validity of the dislocation punching model is verified by comparing the analytical results with limited experimental results, resulting in a good agreement.

  11. Intrauterine Temporomandibular Joint Dislocation: Prenatal Sonographic Evaluation

    PubMed Central

    Çil, Ahmet Said; Bozkurt, Murat; Bozkurt, Duygu Kara

    2014-01-01

    Congenital temporomandibular joint (TMJ) diseases are very rare disorders and are usually diagnosed in childhood. Developmental disorders of the TMJ such as hypoplasia, hyperplasia, and aplasia of the TMJ compartments are characterized by TMJ dysfunction. In childhood, these patients experience recurrent dislocation, pain, and malocclusion. We present the case of a 25-week fetus with unilateral TMJ dislocation with fluid retention in the joint diagnosed by ultrasonography. To the best of our knowledge, this is the first case of TMJ dislocation diagnosed by ultrasonographic evaluation during the prenatal period. PMID:23669613

  12. Intrauterine temporomandibular joint dislocation: prenatal sonographic evaluation.

    PubMed

    Çil, Ahmet Said; Bozkurt, Murat; Bozkurt, Duygu Kara

    2014-09-01

    Congenital temporomandibular joint (TMJ) diseases are very rare disorders and are usually diagnosed in childhood. Developmental disorders of the TMJ such as hypoplasia, hyperplasia, and aplasia of the TMJ compartments are characterized by TMJ dysfunction. In childhood, these patients experience recurrent dislocation, pain, and malocclusion. We present the case of a 25-week fetus with unilateral TMJ dislocation with fluid retention in the joint diagnosed by ultrasonography. To the best of our knowledge, this is the first case of TMJ dislocation diagnosed by ultrasonographic evaluation during the prenatal period. PMID:23669613

  13. Primary Total Hip Arthroplasty Using Third Generation Ceramic-Ceramic Articulation: Results after a Minimum of Three-years of Follow-up

    PubMed Central

    Lee, Dong Woo

    2014-01-01

    Purpose This study assessed the short term clinicoradiological results of primary total hip arthroplasty using third generation ceramic-ceramic articulation Accolade TMZF femoral stems. Materials and Methods Two hundred and seventy two patients (294 hips) with primary total hip arthroplasty using third generation ceramic-ceramic articulation Accolade TMZF femoral stems who had been followed-up for a minimum of 3 years were included. Clinicoradiological results were analyzed and postoperative complications were observed. Results At final follow-up, mean Harris hip score was increased from 52 to 94 points. On radiogical evaluation, the average acetabular inclination was 42 degrees and the average acetabular anteversion was 15 degrees. Neither osteolysis nor loosening were observed around the acetabulum or proximal femur. Among 294 acetabular cups, 293 cups (99.66%) achieved stable fixation. Regarding the 294 femoral stems, 286 (97.28%) had bony fixation, 7 (2.38%) had fibrous fixation, and none were found to have unstable stem fixation. Proximal bone resorption was observed in 17 hips (5.78%; only Grade 1) and radiolucent lines were observed in 88 hips (29.93%), however, all were around the distal smooth portion of the stems. Postoperative complications included dislocation in 6 hips (2.04%), heterotopic ossification in 3 hips (1.02%), ceramic fractures in 4 hips (1.36%), superficial infection in 1 hip (0.34%), and squeaking in 8 hips (2.72%). Conclusion The short term clinicoradiological results of primary total hip arthroplasty using third generation ceramic-ceramic articulation and Accolade TMZF femoral stems together with Secur-Fit acetabular cups were satisfactory. However, problems such as ceramic fractures and squeaking after arthroplasty were observed. Additional studies are necessary in order to develop methods that may reduce or eliminate these complications.

  14. Creep of quartz by dislocation and grain boundary processes

    NASA Astrophysics Data System (ADS)

    Fukuda, J. I.; Holyoke, C. W., III; Kronenberg, A. K.

    2015-12-01

    Wet polycrystalline quartz aggregates deformed at temperatures T of 600°-900°C and strain rates of 10-4-10-6 s-1 at a confining pressure Pc of 1.5 GPa exhibit plasticity at low T, governed by dislocation glide and limited recovery, and grain size-sensitive creep at high T, governed by diffusion and sliding at grain boundaries. Quartz aggregates were HIP-synthesized, subjecting natural milky quartz powder to T=900°C and Pc=1.5 GPa, and grain sizes (2 to 25 mm) were varied by annealing at these conditions for up to 10 days. Infrared absorption spectra exhibit a broad OH band at 3400 cm-1 due to molecular water inclusions with a calculated OH content (~4000 ppm, H/106Si) that is unchanged by deformation. Rate-stepping experiments reveal different stress-strain rate functions at different temperatures and grain sizes, which correspond to differing stress-temperature sensitivities. At 600-700°C and grain sizes of 5-10 mm, flow law parameters compare favorably with those for basal plasticity and dislocation creep of wet quartzites (effective stress exponents n of 3 to 6 and activation enthalpy H* ~150 kJ/mol). Deformed samples show undulatory extinction, limited recrystallization, and c-axis maxima parallel to the shortening direction. Similarly fine-grained samples deformed at 800°-900°C exhibit flow parameters n=1.3-2.0 and H*=135-200 kJ/mol corresponding to grain size-sensitive Newtonian creep. Deformed samples show some undulatory extinction and grain sizes change by recrystallization; however, grain boundary deformation processes are indicated by the low value of n. Our experimental results for grain size-sensitive creep can be compared with models of grain boundary diffusion and grain boundary sliding using measured rates of silicon grain boundary diffusion. While many quartz mylonites show microstructural and textural evidence for dislocation creep, results for grain size-sensitive creep may apply to very fine-grained (<10 mm) quartz mylonites.

  15. Canonical Quantization of Crystal Dislocation and Electron-Dislocation Scattering in an Isotropic Media

    NASA Astrophysics Data System (ADS)

    Li, Mingda; Cui, Wenping; Dresselhaus, M. S.; Chen, Gang; MIT Team; Boston College Team

    Crystal dislocations govern the plastic mechanical properties of materials but also affect the electrical and optical properties. However, a fundamental and decent quantum-mechanical theory of dislocation remains undiscovered for decades. Here we present an exact and manageable Hamiltonian theory for both edge and screw dislocation line in an isotropic media, where the effective Hamiltonian of a single dislocation line can be written in a harmonic-oscillator-like form, with closed-form quantized 1D phonon-like excitation. Moreover a closed-form, position dependent electron-dislocation coupling strength is obtained, from which we obtained good agreement of relaxation time when comparing with classical results. This Hamiltonian provides a platform to study the effect of dislocation to materials' non-mechanical properties from a fundamental Hamiltonian level.

  16. [Pseudotumors caused by hip prostheses].

    PubMed

    Helkamaa, Teemu; Lohman, Martina; Alberty, Anne

    2015-01-01

    More than 100000 hip replacements have been performed in Finland. In the hip replacement operations performed due to osteoarthritis, the artificial joint surfaces are made of metal, plastic or ceramics. Pseudotumors associated with metal-on-metal (MoM) sliding surfaces have received worldwide attention. Soft issue lesions, not always symptomatic, may develop around the joint replacements. These may even require joint revision surgery. PMID:26237883

  17. Fundamentals in generalized elasticity and dislocation theory of quasicrystals: Green tensor, dislocation key-formulas and dislocation loops

    NASA Astrophysics Data System (ADS)

    Lazar, Markus; Agiasofitou, Eleni

    2014-12-01

    The present work provides fundamental quantities in generalized elasticity and dislocation theory of quasicrystals. In a clear and straightforward manner, the three-dimensional Green tensor of generalized elasticity theory and the extended displacement vector for an arbitrary extended force are derived. Next, in the framework of dislocation theory of quasicrystals, the solutions of the field equations for the extended displacement vector and the extended elastic distortion tensor are given; that is, the generalized Burgers equation for arbitrary sources and the generalized Mura-Willis formula, respectively. Moreover, important quantities of the theory of dislocations as the Eshelby stress tensor, Peach-Koehler force, stress function tensor and the interaction energy are derived for general dislocations. The application to dislocation loops gives rise to the generalized Burgers equation, where the displacement vector can be written as a sum of a line integral plus a purely geometric part. Finally, using the Green tensor, all other dislocation key-formulas for loops, known from the theory of anisotropic elasticity, like the Peach-Koehler stress formula, Mura-Willis equation, Volterra equation, stress function tensor and the interaction energy are derived for quasicrystals.

  18. Automated identification and indexing of dislocations in crystal interfaces

    SciTech Connect

    Stukowski, Alexander; Bulatov, Vasily V.; Arsenlis, Athanasios

    2012-10-31

    Here, we present a computational method for identifying partial and interfacial dislocations in atomistic models of crystals with defects. Our automated algorithm is based on a discrete Burgers circuit integral over the elastic displacement field and is not limited to specific lattices or dislocation types. Dislocations in grain boundaries and other interfaces are identified by mapping atomic bonds from the dislocated interface to an ideal template configuration of the coherent interface to reveal incompatible displacements induced by dislocations and to determine their Burgers vectors. Additionally, the algorithm generates a continuous line representation of each dislocation segment in the crystal and also identifies dislocation junctions.

  19. Model for dislocation locking by oxygen gettering in silicon crystals

    NASA Astrophysics Data System (ADS)

    Maroudas, Dimitris; Brown, Robert A.

    1991-04-01

    Oxygen gettering to dislocations slows and stops dislocation motion caused by applied stress in silicon crystals. A model is presented that quantitatively describes the inhibition of dislocation motion by accounting for the drag caused by the oxygen atmosphere in the crystal around the dislocation and for oxygen aggregates inside the dislocation core. The oxygen distribution is computed by analysis of diffusion and stress-assisted migration in the crystalline lattice. The predictions of the model agree quantitatively with the experimental data of Imai and Sumino. Hysteresis is predicted in the dependence of the dislocation velocity on applied stress and explains the difference in the unlocking and locking stresses for dislocation motion.

  20. Automated identification and indexing of dislocations in crystal interfaces

    DOE PAGESBeta

    Stukowski, Alexander; Bulatov, Vasily V.; Arsenlis, Athanasios

    2012-10-31

    Here, we present a computational method for identifying partial and interfacial dislocations in atomistic models of crystals with defects. Our automated algorithm is based on a discrete Burgers circuit integral over the elastic displacement field and is not limited to specific lattices or dislocation types. Dislocations in grain boundaries and other interfaces are identified by mapping atomic bonds from the dislocated interface to an ideal template configuration of the coherent interface to reveal incompatible displacements induced by dislocations and to determine their Burgers vectors. Additionally, the algorithm generates a continuous line representation of each dislocation segment in the crystal andmore » also identifies dislocation junctions.« less

  1. Dislocation dynamics simulations of interactions between gliding dislocations and radiation induced prismatic loops in zirconium

    NASA Astrophysics Data System (ADS)

    Drouet, Julie; Dupuy, Laurent; Onimus, Fabien; Mompiou, Frédéric; Perusin, Simon; Ambard, Antoine

    2014-06-01

    The mechanical behavior of Pressurized Water Reactor fuel cladding tubes made of zirconium alloys is strongly affected by neutron irradiation due to the high density of radiation induced dislocation loops. In order to investigate the interaction mechanisms between gliding dislocations and loops in zirconium, a new nodal dislocation dynamics code, adapted to Hexagonal Close Packed metals, has been used. Various configurations have been systematically computed considering different glide planes, basal or prismatic, and different characters, edge or screw, for gliding dislocations with -type Burgers vectors. Simulations show various interaction mechanisms such as (i) absorption of a loop on an edge dislocation leading to the formation of a double super-jog, (ii) creation of a helical turn, on a screw dislocation, that acts as a strong pinning point or (iii) sweeping of a loop by a gliding dislocation. It is shown that the clearing of loops is more favorable when the dislocation glides in the basal plane than in the prismatic plane explaining the easy dislocation channeling in the basal plane observed after neutron irradiation by transmission electron microscopy.

  2. Complete dorsal dislocation of the carpal scaphoid with perilunate dorsal dislocation

    PubMed Central

    Kang, Jong Woo; Park, Jong Hoon; Suh, Dong Hun; Park, Jong Woong

    2016-01-01

    Complete dorsal dislocation of the carpal scaphoid combined with dorsal perilunate dislocation is an extremely rare carpal injury. We describe the case of a 23-year-old man who presented with a complete dorsal dislocation of the carpal scaphoid, combined with a perilunate dislocation. Surgical treatment was performed with open reduction and interosseus ligament repair. At 4 years follow up, the patient's wrist pain had completely resolved without limitations of wrist joint motion and without evidence of avascular necrosis of the carpal scaphoid. PMID:27512229

  3. Energy and entropy of interacting dislocations

    SciTech Connect

    Ladd, A.J.C.; Hoover, W.G.

    1982-11-15

    The energy and entropy of interacting edge dislocations have been calculated by atomistic simulations, with the use of piecewise-linear forces in a two-dimensional triangular lattice. We conclude that the interaction energy between small groups of dislocations is well described by continuum mechanics for separations greater than a few lattice spacings. Our calculations enable us to make a precise determination of the core energy, which is an essential parameter in determining dislocation multiplication rates. We find also that continuum mechanics gives an accurate representation of the interaction of a dislocation pair with a homogeneous elastic stress field. The vibrational contribution to the entropy of such a pair is small, about 0.3k.

  4. Quenched pinning and collective dislocation dynamics

    PubMed Central

    Ovaska, Markus; Laurson, Lasse; Alava, Mikko J.

    2015-01-01

    Several experiments show that crystalline solids deform in a bursty and intermittent fashion. Power-law distributed strain bursts in compression experiments of micron-sized samples, and acoustic emission energies from larger-scale specimens, are the key signatures of the underlying critical-like collective dislocation dynamics - a phenomenon that has also been seen in discrete dislocation dynamics (DDD) simulations. Here we show, by performing large-scale two-dimensional DDD simulations, that the character of the dislocation avalanche dynamics changes upon addition of sufficiently strong randomly distributed quenched pinning centres, present e.g. in many alloys as immobile solute atoms. For intermediate pinning strength, our results adhere to the scaling picture of depinning transitions, in contrast to pure systems where dislocation jamming dominates the avalanche dynamics. Still stronger disorder quenches the critical behaviour entirely. PMID:26024505

  5. Quenched pinning and collective dislocation dynamics.

    PubMed

    Ovaska, Markus; Laurson, Lasse; Alava, Mikko J

    2015-01-01

    Several experiments show that crystalline solids deform in a bursty and intermittent fashion. Power-law distributed strain bursts in compression experiments of micron-sized samples, and acoustic emission energies from larger-scale specimens, are the key signatures of the underlying critical-like collective dislocation dynamics - a phenomenon that has also been seen in discrete dislocation dynamics (DDD) simulations. Here we show, by performing large-scale two-dimensional DDD simulations, that the character of the dislocation avalanche dynamics changes upon addition of sufficiently strong randomly distributed quenched pinning centres, present e.g. in many alloys as immobile solute atoms. For intermediate pinning strength, our results adhere to the scaling picture of depinning transitions, in contrast to pure systems where dislocation jamming dominates the avalanche dynamics. Still stronger disorder quenches the critical behaviour entirely. PMID:26024505

  6. Robotic-Arm Assisted Surgery in Total Hip Arthroplasty.

    PubMed

    Elmallah, Randa K; Cherian, Jeffrey J; Jauregui, Julio J; Padden, David A; Harwin, Steven F; Mont, Michael A

    2015-05-01

    Complications following total hip arthroplasty (THA), such as dislocation, component loosening and wear, continue to be common indications for revision surgery. Multiple studies have attributed some of these problems to poor acetabular cup alignment and placement outside of the purported radiographic safe zone. In addition, it has been shown that conventional manually performed acetabular cup placement may not lead to optimal alignment, regardless of surgical experience. Additionally, incorrect leg length and offset can lead to dissatisfaction and instability. Therefore, robotic-arm assisted surgery has been introduced to improve accuracy of cup placement and leg length, and to offset with the aim of reducing the risk of hip instability and improving satisfaction after primary THA. Our aim was to prospectively review the use of robotic-arm assisted surgery in 224 patients and to assess whether the pre-operatively determined radiographic targets were achieved post-operatively and the proportion of acetabular cups outside of the safe zone. Pre-determined anteversion and inclination were 15 and 40 degrees, respectively. Our results have shown that the use of robotic-arm assisted surgery resulted in a post-operative mean inclination of 40 degrees (range, 34 to 51 degrees) and a mean anteversion of 16 degrees (range, 9 to 25 degrees). Ninety-nine percent of the patients remained within the pre-designated safe zone. Evidence has shown that robotic-arm assisted surgery may have improved accuracy in cup placement when compared to conventional surgery and possibly to computer-assisted surgery. When compared to the literature on robotic-arm assisted surgery, our results were comparable. We believe that this surgical technique may aid in reducing post-operative THA complications, such as aseptic loosening and dislocations, but further prospective studies are needed to evaluate clinical outcomes and long-term results. PMID:26055021

  7. Dislocation shielding of a cohesive crack

    NASA Astrophysics Data System (ADS)

    Bhandakkar, Tanmay K.; Chng, Audrey C.; Curtin, W. A.; Gao, Huajian

    2010-04-01

    Dislocation interaction with a cohesive crack is of increasing importance to computational modelling of crack nucleation/growth and related toughening mechanisms in confined structures and under cyclic fatigue conditions. Here, dislocation shielding of a Dugdale cohesive crack described by a rectangular traction-separation law is studied. The shielding is completely characterized by three non-dimensional parameters representing the effective fracture toughness, the cohesive strength, and the distance between the dislocations and the crack tip. A closed form analytical solution shows that, while the classical singular crack model predicts that a dislocation can shield or anti-shield a crack depending on the sign of its Burgers vector, at low cohesive strengths a dislocation always shields the cohesive crack irrespective of the Burgers vector. A numerical study shows the transition in shielding from the classical solution of Lin and Thomson (1986) in the high strength limit to the solution in the low strength limit. An asymptotic analysis yields an approximate analytical model for the shielding over the full range of cohesive strengths. A discrete dislocation (DD) simulation of a large (>10 3) number of edge dislocations interacting with a cohesive crack described by a trapezoidal traction-separation law confirms the transition in shielding, showing that the cohesive crack does behave like a singular crack at very high cohesive strengths (˜7 GPa), but that significant deviations in shielding between singular and cohesive crack predictions arise at cohesive strengths around 1GPa, consistent with the analytic models. Both analytical and numerical studies indicate that an appropriate crack tip model is essential for accurately quantifying dislocation shielding for cohesive strengths in the GPa range.

  8. Dislocation dynamics of web type silicon ribbon

    NASA Technical Reports Server (NTRS)

    Dillon, O. W., Jr.; Tsai, C. T.; De Angelis, R. J.

    1987-01-01

    Silicon ribbon grown by the dendritic web process passes through a rapidly changing thermal profile in the growth direction. This rapidly changing profile induces stresses which produce changes in the dislocation density in the ribbon. A viscoplastic material response function (Haasen-Sumino model) is used herein to calculate the stresses and the dislocation density at each point in the silicon ribbon. The residual stresses are also calculated.

  9. Isolated Proximal Tibiofibular Dislocation during Soccer

    PubMed Central

    Chiu, Casey; Sheele, Johnathan Michael

    2015-01-01

    Proximal tibiofibular dislocations are rarely encountered in the Emergency Department (ED). We present a case involving a man presenting to the ED with left knee pain after making a sharp left turn on the soccer field. His physical exam was only remarkable for tenderness over the lateral fibular head. His X-rays showed subtle abnormalities of the tibiofibular joint. The dislocation was reduced and the patient was discharged from the ED with orthopedic follow-up. PMID:26713164

  10. Atomistic modeling of dislocation-interface interactions

    SciTech Connect

    Wang, Jian; Valone, Steven M; Beyerlein, Irene J; Misra, Amit; Germann, T. C.

    2011-01-31

    Using atomic scale models and interface defect theory, we first classify interface structures into a few types with respect to geometrical factors, then study the interfacial shear response and further simulate the dislocation-interface interactions using molecular dynamics. The results show that the atomic scale structural characteristics of both heterophases and homophases interfaces play a crucial role in (i) their mechanical responses and (ii) the ability of incoming lattice dislocations to transmit across them.

  11. Investigation of the Dynamics of a Screw Dislocation in Copper

    NASA Astrophysics Data System (ADS)

    Kolupaeva, S. N.; Petelina, Yu. P.; Polosukhin, K. A.; Petelin, A. E.

    2015-08-01

    A modification of the mathematical model of forming the crystallographic shear band is proposed in which the strength of elastic interaction between all dislocations of the forming dislocation pileups is taken into account in addition to the Peach-Keller force; lattice, impurity, and dislocation friction; linear tension; viscous braking; and intensity of generation of point defects behind kinks. The model is used to investigate the influence of the dislocation density on the time characteristics of the formation of dislocation loops in copper.

  12. The incidence of avascular necrosis and the radiographic outcome following medial open reduction in children with developmental dysplasia of the hip: a systematic review.

    PubMed

    Gardner, R O E; Bradley, C S; Howard, A; Narayanan, U G; Wedge, J H; Kelley, S P

    2014-02-01

    The incidence of clinically significant avascular necrosis (AVN) following medial open reduction of the dislocated hip in children with developmental dysplasia of the hip (DDH) remains unknown. We performed a systematic review of the literature to identify all clinical studies reporting the results of medial open reduction surgery. A total of 14 papers reporting 734 hips met the inclusion criteria. The mean follow-up was 10.9 years (2 to 28). The rate of clinically significant AVN (types 2 to 4) was 20% (149/734). From these papers 221 hips in 174 children had sufficient information to permit more detailed analysis. The rate of AVN increased with the length of follow-up to 24% at skeletal maturity, with type 2 AVN predominating in hips after five years' follow-up. The presence of AVN resulted in a higher incidence of an unsatisfactory outcome at skeletal maturity (55% vs 20% in hips with no AVN; p < 0.001). A higher rate of AVN was identified when surgery was performed in children aged < 12 months, and when hips were immobilised in ≥ 60° of abduction post-operatively. Multivariate analysis showed that younger age at operation, need for further surgery and post-operative hip abduction of ≥ 60° increased the risk of the development of clinically significant AVN. PMID:24493198

  13. Dislocation electrical conductivity of synthetic diamond films

    SciTech Connect

    Samsonenko, S. N. Samsonenko, N. D.

    2009-05-15

    A relationship between the electric resistance of single-crystal homoepitaxial and polycrystalline diamond films and their internal structure has been investigated. It is established that the electrical conductivity of undoped homoepitaxial and polycrystalline diamond films is directly related to the dislocation density in them. A relation linking the resistivity {rho} ({approx}10{sup 13}-10{sup 15} {omega} cm) with the dislocation density {gamma} ({approx}10{sup 14}-4 x 10{sup 16} m{sup -2}) is obtained. The character of this correlation is similar for both groups of homoepitaxial and polycrystalline diamond films. Thin ({approx}1-8 {mu}m) homoepitaxial and polycrystalline diamond films with small-angle dislocation boundaries between mosaic blocks exhibit dislocation conductivity. The activation energy of dislocation acceptor centers was calculated from the temperature dependence of the conductivity and was found to be {approx}0.3 eV. The conduction of thick diamond films (h > 10 {mu}m) with the resistivity {rho} {approx} 10{sup 8} {omega} cm is determined by the conduction of intercrystallite boundaries, which have a nondiamond hydrogenated structure. The electronic properties of the diamond films are compared with those of natural semiconductor diamonds of types IIb and Ic, in which dislocation acceptor centers have activation energies in the range 0.2-0.35 eV and are responsible for hole conduction.

  14. Dislocation motion in solid hcp 3He

    NASA Astrophysics Data System (ADS)

    Beamish, John; Cheng, Zhi Gang

    At temperatures above about 100 mK, dislocations reduce the shear modulus of hcp 4He by as much as 90 %. This occurs when dislocations thermally unbind from the 3He impurities that pin them, becoming extraordinarily mobile. The elastic softening is accompanied by a thermally activated dissipation peak due to the 3He impurities. At higher temperatures the dissipation has an ωT4 dependence caused by scattering of thermal phonons from moving dislocations. Previous measurements on the fermi solid, hcp 3He, showed a similar dislocation softening, but the corresponding dissipation was not measured. We have extended these measurements by measuring the temperature, amplitude and frequency dependence of both the shear modulus and the dissipation in hcp 3He. The dissipation behavior is very different from that of hcp 4He. Neither the impurity unbinding peak associated with the elastic softening, nor the high temperature phonon scattering dissipation, were observed. Instead, there is a large and non-thermally activated dissipation which is largest at low frequencies. We believe that this unexpected dissipation is associated with a new dislocation damping mechanism in 3He, perhaps associated with spin rearrangements caused by moving dislocations. This work was supported by a grant from NSERC Canada.

  15. Isolated dorsal dislocation of the lunate.

    PubMed

    Siddiqui, Na; Sarkar, Sp

    2012-01-01

    Lunate dislocations are well described in the volar direction as part of the perilunate dislocation, sometimes together with fractures of the other carpal bones or distal radius, as described by the anatomical studies of Mayfield [1]. It is a result of disruption of the complex inter-carpal and radiocarpal ligaments that hold the well conforming carpus in their normal position. Given the strength of these structures a significant trauma is required to cause them to fail.However, we present a case of a patient who not only presented with relatively trivial trauma that resulted in a lunate dislocation, but it was also in the dorsal direction and not associated with any fracture or neurological compromise. In addition, she presented several days after her injury.We treated her with closed manipulation and percutaneous K-wire fixation followed by a short period of immobilisation in a Plaster-of-Paris cast, with rapid return to full duties at work.As many volar lunate dislocations may be missed at presentation, we suggest that in patients with relatively trivial trauma there should also be a suspicion of the lunate dislocating dorsally, which may be treated successfully without the aggressive open surgery usually required in volar perilunate dislocations. PMID:23248723

  16. Dislocation creep of fine-grained olivine

    NASA Astrophysics Data System (ADS)

    Faul, U. H.; Fitz Gerald, J. D.; Farla, R. J. M.; Ahlefeldt, R.; Jackson, I.

    2011-01-01

    Deformation experiments conducted in a gas medium apparatus at temperatures from 1200 to 1350°C with a fine-grained, solution-gelation derived Fe-bearing olivine show a stress dependence of the strain rate at stresses above ˜150 MPa, which is much stronger than previously reported for polycrystalline samples. The data can be fit by a power law with ??σn with n ˜ 7-8, or equally well by a Peierls creep law with exponential stress dependence. Due to the observed strong stress dependence the samples deform at significantly higher strain rates at a given stress than single crystals or coarse-grained polycrystals with n ˜ 3.5. TEM observations indicate the presence of dislocations with at least two different Burgers vectors, with free dislocations predominantly of screw character. Subgrain walls are present but are only weakly developed and have small misorientation angles. Both the rheology and dislocation structures are consistent with creep rate-limited by dislocation glide or cross slip for aggregates with grain sizes smaller than or approaching the recrystallized grain size. Deformation mechanism maps extrapolated to lithospheric temperatures using the melt-free diffusion creep rheology of Faul and Jackson (2007), the dislocation creep rheology of Hirth and Kohlstedt (2003), and the results described here indicate that deformation conditions of ultramylonitic shear zones fall near the triple point of Peierls, dislocation, and diffusion creep.

  17. Generalized dynamics of moving dislocations in quasicrystals

    NASA Astrophysics Data System (ADS)

    Agiasofitou, Eleni; Lazar, Markus; Kirchner, Helmut

    2010-12-01

    A theoretical framework for dislocation dynamics in quasicrystals is provided according to the continuum theory of dislocations. Firstly, we present the fundamental theory for moving dislocations in quasicrystals giving the dislocation density tensors and introducing the dislocation current tensors for the phonon and phason fields, including the Bianchi identities. Next, we give the equations of motion for the incompatible elastodynamics as well as for the incompatible elasto-hydrodynamics of quasicrystals. We continue with the derivation of the balance law of pseudomomentum thereby obtaining the generalized forms of the Eshelby stress tensor, the pseudomomentum vector, the dynamical Peach-Koehler force density and the Cherepanov force density for quasicrystals. The form of the dynamical Peach-Koehler force for a straight dislocation is obtained as well. Moreover, we deduce the balance law of energy that gives rise to the generalized forms of the field intensity vector and the elastic power density of quasicrystals. The above balance laws are produced for both models. The differences between the two models and their consequences are revealed. The influences of the phason fields as well as of the dynamical terms are also discussed.

  18. Generalized dynamics of moving dislocations in quasicrystals.

    PubMed

    Agiasofitou, Eleni; Lazar, Markus; Kirchner, Helmut

    2010-12-15

    A theoretical framework for dislocation dynamics in quasicrystals is provided according to the continuum theory of dislocations. Firstly, we present the fundamental theory for moving dislocations in quasicrystals giving the dislocation density tensors and introducing the dislocation current tensors for the phonon and phason fields, including the Bianchi identities. Next, we give the equations of motion for the incompatible elastodynamics as well as for the incompatible elasto-hydrodynamics of quasicrystals. We continue with the derivation of the balance law of pseudomomentum thereby obtaining the generalized forms of the Eshelby stress tensor, the pseudomomentum vector, the dynamical Peach-Koehler force density and the Cherepanov force density for quasicrystals. The form of the dynamical Peach-Koehler force for a straight dislocation is obtained as well. Moreover, we deduce the balance law of energy that gives rise to the generalized forms of the field intensity vector and the elastic power density of quasicrystals. The above balance laws are produced for both models. The differences between the two models and their consequences are revealed. The influences of the phason fields as well as of the dynamical terms are also discussed. PMID:21406784

  19. Review on squeaking hips.

    PubMed

    Levy, Yadin David; Munir, Selin; Donohoo, Shane; Walter, William Lindsay

    2015-11-18

    Squeaking is a well-recognized complication for hard-on-hard bearings. The nature of squeaking is not yet completely understood however it is considered a multifactorial phenomenon. Patient, implant, and surgical factors play a role in squeaking. It is believed that mechanisms damaging the fluid film lubrication in which these bearings function optimally have a critical role. Such mechanisms include edge loading, stripe wear, impingement, third body particles and ceramic fracture. The resonance of metallic parts can produce noise in the human audible range hence the implant metallurgic composition and design may play a role. Implant positioning can facilitate impingement and edge loading enhancing the occurrence of squeaking. The recent introduction of large heads (> 36 mm) 4(th) generation ceramic-on-ceramic bearing may accentuate the conditions facilitating noise formation; however the current literature is insufficient. Clinically, squeaking may manifest in extreme hip positions or during normal gait cycle however it is rarely associated with pain. Evaluations of patients with squeaking include clinical and radiographic assessments. Computer tomography is recommended as it can better reveal ceramic breakage and implant malposition. The treatments for most squeaking patients include reassurance and activity modification. However for some, noise can be a problem, requiring further surgical intervention. In the occurrence of ceramic fracture, implant failure, extreme components malposition, instability and impingement, surgery should be advised. This review will aim to discuss the current literature regarding squeaking. PMID:26601063

  20. Review on squeaking hips

    PubMed Central

    Levy, Yadin David; Munir, Selin; Donohoo, Shane; Walter, William Lindsay

    2015-01-01

    Squeaking is a well-recognized complication for hard-on-hard bearings. The nature of squeaking is not yet completely understood however it is considered a multifactorial phenomenon. Patient, implant, and surgical factors play a role in squeaking. It is believed that mechanisms damaging the fluid film lubrication in which these bearings function optimally have a critical role. Such mechanisms include edge loading, stripe wear, impingement, third body particles and ceramic fracture. The resonance of metallic parts can produce noise in the human audible range hence the implant metallurgic composition and design may play a role. Implant positioning can facilitate impingement and edge loading enhancing the occurrence of squeaking. The recent introduction of large heads (> 36 mm) 4th generation ceramic-on-ceramic bearing may accentuate the conditions facilitating noise formation; however the current literature is insufficient. Clinically, squeaking may manifest in extreme hip positions or during normal gait cycle however it is rarely associated with pain. Evaluations of patients with squeaking include clinical and radiographic assessments. Computer tomography is recommended as it can better reveal ceramic breakage and implant malposition. The treatments for most squeaking patients include reassurance and activity modification. However for some, noise can be a problem, requiring further surgical intervention. In the occurrence of ceramic fracture, implant failure, extreme components malposition, instability and impingement, surgery should be advised. This review will aim to discuss the current literature regarding squeaking. PMID:26601063

  1. Eponymous hip joint approaches.

    PubMed

    Somford, Matthijs P; Hoornenborg, Daniël; Wiegerinck, Johannes I; Bolder, Stefan B T; Schreurs, Berend W

    2016-07-01

    After the low friction arthroplasty by John Charnley was no longer confined to specialized hospitals but commonplace in the general orthopedic practice, the issue remained how to most optimally reach the hip. The names of the authors of these approaches remain in a lot of cases connected to the approach. By evaluating the original articles in which the approaches are described we ascertain the original description and technique. By various sources we obtained the (short) biography of the people whose name is connected to the approach. Our research covers the biographies of colleagues Smith-Petersen, Watson-Jones, Hardinge, Charnley, Moore and Ludloff. The eponymous approaches are shown and described after the short biography on each individual. This study shows that without the work of our colleagues we cannot proceed in our profession. An understanding and knowledge of the people who dedicated themselves to developing the orthopedic surgery to the high standard it has today is the least honour we should give them. PMID:27139185

  2. Kinematic radiography of the hip joint after hip resurfacing arthroplasty.

    PubMed

    Kawashima, Hiroki; Kajino, Yoshitomo; Kabata, Tamon; Tsuchiya, Hiroyuki; Sanada, Shigeru; Ichikawa, Katsuhiro

    2016-07-01

    This study aimed to evaluate the usefulness of dynamic radiography using a dynamic flat-panel detector (FPD) system after hip resurfacing arthroplasty (HRA). A total of 32 hips of 26 patients who underwent HRA were included. Sequential images of active abduction in the supine position and flexion in the 45° semilateral position were obtained using the FPD system. We examined the imaging findings of impingement between the acetabular component and femoral neck with cooperative motion at maximal exercise. Moreover, the central component coordinate of the acetabulum and femoral head sides was measured. For abduction motion, impingement was detected in two (6.3 %) hips between the superior portion of the femoral neck and acetabular component. For flexion motion, impingement was detected in 19 (59.4 %) hips. There were no findings of subluxation between the acetabular component and femoral neck after impingement, but cooperative motion of lumbar and pelvic flexion was observed. There was no significant difference in the center-to-center distance regardless of the presence or absence of impingement. Detailed postoperative kinematics of the hips after HRA showed that the proposed dynamic FPD system could reveal acquired impingement and cooperative motion as dynamic images and possibly reveal findings that would be unobservable using static images. PMID:27207072

  3. Sliding screw implants for extracapsular hip fractures.

    PubMed

    Mavrogenis, Andreas F; Kouvidis, George; Stavropoulos, Nikolaos A; Stavrakakis, Loannis; Katonis, Pavlos; Papagelopoulos, Panayiotis J

    2012-01-01

    Hip fractures are associated with significant mortality and morbidity for the patients, more dependent residual status, and increased socio-economic cost. Many hip-fracture patients experience severe functional impairment, and most never recover their pre-fracture level of function. Current research has sought to identify the most effective treatments to reduce the incidence of hip fractures, improve survival and quality of life, and minimize complications and disability. The treatment of these fractures in the elderly aims to return these people to their pre-fracture mobility and functional level. This article reviews the surgical treatment options for extracapsular hip fractures and discusses their associated advantages, disadvantages, and complications. Two types of implants are currently available: the dynamic hip screw (DHS), and the intramedullary hip nail with one or two sliding screws. In this review, no clear advantage of one implant over another for the treatment of extracapsular hip fractures was evident. Both the DHS and hip nails can be used successfully for the treatment of stable hip fractures; for unstable fractures and low subtrochanteric fractures, hip nails are preferred. Although hip nails are associated with limited exposure, lower blood loss and transfusion requirements, and shorter operative time, complications are more common with hip nails. Long-term survival and function are similar in the two approaches. Hip nails with two sliding screws do not seem to make the difference in clinical practice that is reported in biomechanical studies. PMID:23016784

  4. Birmingham Hip Resurfacing: A Single Surgeon Series Reported at a Minimum of 10 Years Follow-Up.

    PubMed

    Mehra, Akshay; Berryman, Fiona; Matharu, Gulraj S; Pynsent, Paul B; Isbister, Eric S

    2015-07-01

    We report outcomes on 120 Birmingham Hip Resurfacings (BHRs) (mean age 50 years) at a minimum of ten-years follow-up. Cases were performed by one surgeon and included his learning curve. Six hips were revised, with no revisions for infection, dislocation, or adverse reaction to metal debris. Ten-year survival was 94.2% (95% confidence interval (CI) 88.8%-98.7%) for all revisions and 96.1% (95% CI 91.5%-99.8%) for revisions for aseptic loosening. Gender (P = 0.463) and head size (P = 0.114) did not affect revision risk. Mean post-operative Harris hip score was 84.0. Contrary to previous independent reports, good outcomes into the second decade were achieved with the BHR in both men and women. Longer term follow-up will confirm whether these promising outcomes in women continue. PMID:25769743

  5. Sciatic nerve palsy associated with total hip arthroplasty.

    PubMed

    Dhillon, M S; Nagi, O N

    1992-01-01

    Six cases of clinically evident sciatic or peroneal nerve palsy occurred in a consecutive series of 380 total hip arthroplasties (THA). An additional eight cases of peroneal nerve palsy due to pressure from Thomas splint or tight bandages were seen. Factors apparently causing nerve palsy were significant lateralization and lengthening in four cases and dislocation of the hip in one case. The cases with neuroapraxia of the peroneal nerve were seen from the third to the fifth day of Thomas splint immobilization. EMG studies were conducted in all six group 1 patients; at the end of one year the results were good in two cases, fair in three cases, and poor in one case. The results suggest that limb lengthening should be limited to 4 cm to minimize this complication. It was also seen that patients with peroneal nerve palsy due to local compression do well, though some are bothered by mild residual dysesthesia over the dorsum of the foot. In contrast, patients with sciatic nerve palsy do not have such a good outlook. PMID:1345646

  6. [Metal spongiosa endoprostheses for surgical revision of the hip joint].

    PubMed

    Lütten, C; Lorenz, H; Thomas, W

    1990-01-01

    On the basis of 60 revision operations which were carried out on hip joints with mainly aseptic loosened cemented endoprosthesis and which also had, to some extent, distinct macrophagic induced osteolysis zones, it could be shown that implants with a metal spongiosa surface structure offer a good chance of an enduring revitalisation in the anchorage position and, thereby, are able to achieve a permanently stable endoprosthesis fixation. The expansion defects could be filled by means of homologous or autologous spongiosa transplantation. The post-operative X-ray check-up showed a vital inward-growing healing. All the endoprosthesis remained in situ during the follow-up examination period of, on average, 12.1 months. In accordance with the Merle D'Aubigne hip evaluation scheme, 43.3% showed an excellent result; 40% a good one; 13.3% were satisfactory; and only 3.4% showed a bad result. Major complications which occurred were: two intra-operative femoral stem fractures which had to be taken care of osteosynthetically; a repeat operation which had to take place during the first post-operative week because of a dislocation of the socket cup; and a luxation which was revised under narcosis. In spite of an increased periarticular ossification's ratio in revision operations, second-class ossification only occurred in 16.7% of all cases and third-class ossification did not occur at all. PMID:2140646

  7. Un trait du francais parle authentique: La dislocation. (A Trait of Authentic Spoken French: Dislocation.)

    ERIC Educational Resources Information Center

    Calve, Pierre

    1983-01-01

    The dislocation of sentence elements in spoken French is seen as allowing the speaker to free himself from certain constraints imposed on word order, position of accents, and grammar. Dislocation is described, its various functions are enumerated, and implications for second language instruction are outlined. (MSE)

  8. Metal-on-Metal Total Hip Resurfacing Arthroplasty

    PubMed Central

    2006-01-01

    conventional THR with a small (28 mm) ball. First, the large femoral head reduces the chance of dislocation, so that rates of dislocation are less than those with conventional THR. Second, the range of motion with hip resurfacing arthroplasty is higher than that achieved with conventional THR. A variety of MOM hip resurfacing implants are used in clinical practice. Six MOM hip resurfacing implants have been issued licences in Canada. Review Strategy A search of electronic bibliographies (OVID Medline, Medline In-Process and Other Non-Indexed Citations, Embase, Cochrane CENTRAL and DSR, INAHTA) was undertaken to identify evidence published from Jan 1, 1997 to October 27, 2005. The search was limited to English-language articles and human studies. The literature search yielded 245 citations. Of these, 11 met inclusion criteria (9 for effectiveness, 2 for safety). The result of the only reported randomized controlled trial on MOM hip resurfacing arthroplasty could not be included in this assessment, because it used a cemented acetabular component, whereas in the new generation of implants, a cementless acetabular component is used. After omitting this publication, only case series remained. Summary of Findings   Health Outcomes The Harris hip score and SF-12 are 2 measures commonly used to report health outcomes in MOM hip resurfacing arthroplasty studies. Other scales used are the Oxford hip score and the University of California Los Angeles hip score. The case series showed that the mean revision rate of MOM hip resurfacing arthroplasty is 1.5% and the incidence of femoral neck fracture is 0.67%. Across all studies, 2 cases of osteonecrosis were reported. Four studies reported improvement in Harris hip scores. However, only 1 study reported a statistically significant improvement. Three studies reported improvement in SF-12 scores, of which 2 reported a significant improvement. One study reported significant improvement in UCLA hip score. Two studies reported postoperative

  9. Neonatal Incidence of Hip Dysplasia

    PubMed Central

    Peled, Eli; Eidelman, Mark; Katzman, Alexander

    2008-01-01

    The advantages of sonographic examination are well known, but its main disadvantage is that it might lead to overdiagnosis, which might cause overtreatment. Variations in the incidence of developmental dysplasia of the hip are well known. We ascertained the incidence of neonatal sonographic developmental dysplasia of the hip without considering the development of those joints during followup. All 45,497 neonates (90,994 hips) born in our institute between January 1992 and December 2001 were examined clinically and sonographically during the first 48 hours of life. Sonography was performed according to Graf’s method, which considers mild hip sonographic abnormalities as Type IIa. We evaluated the different severity type incidence pattern and its influence on the total incidence during and between the investigated years. According to our study, sonographic Type IIa has major effects on the incidence of overall developmental dysplasia of the hip with a correlation coefficient of 0.95, whereas more severe sonographic abnormalities show relatively stable incidence patterns. Level of Evidence: Level I, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18288551

  10. Neutron Diffraction Measurement of Residual Stresses, Dislocation Density and Texture in Zr-bonded U-10Mo ''Mini'' Fuel Foils and Plates

    SciTech Connect

    Brown, Donald W.; Okuniewski, M. A.; Sisneros, Thomas A.; Clausen, Bjorn; Moore, G. A.; Balogh, L

    2014-08-07

    Aluminum clad monolithic uranium 10 weight percent molybdenum (U-10Mo) fuel plates are being considered for conversion of several research and test nuclear reactors from high-enriched to low-enriched uranium fuel due to the inherently high density of fissile material. Comprehensive neutron diffraction measurements of the evolution of the textures, residual phase stresses, and dislocation densities in the individual phases of the mini-foils throughout several processing steps and following hot-isostatic pressing to the Al cladding, have been completed. Recovery and recrystallization of the bare U-10Mo fuel foil, as indicated by the dislocation density and texture, are observed depending on the state of the material prior to annealing and the duration and temperature of the annealing process. In general, the HIP procedure significantly reduces the dislocation density, but the final state of the clad plate, both texture and dislocation density, depends strongly on the final processing step of the fuel foil. In contrast, the residual stresses in the clad fuel plate do not depend strongly on the final processing step of the bare foil prior to HIP bonding. Rather, the residual stresses are dominated by the thermal expansion mismatch of the constituent materials of the fuel plate.

  11. Advances in the theory of the Hall-Petch relation, dislocation pileups and dislocation sources

    NASA Astrophysics Data System (ADS)

    Friedman, Lawrence Henry

    Advances in the theory of dislocations are reported. The Hall-Petch relation is extended, and a continuum level simulation of curvilinear dislocations is developed and used to study the operation of Frank-Read sources. The Hall-Petch relation states that the yield stress, sigma y, or strength against plastic deformation of polycrystalline materials is enhanced by decreasing the grain diameter: sigma y = Kd--1/2 + sigma 0, with K and sigma0 constants. One explanation of this relation is that yielding results from stress concentrated by queues of dislocations known as pileups. The pileup theory of the Hall-Petch relation is extended in two ways. First, two important aspects of pileup formation are incorporated into the theory: the existence of a threshold stress for dislocation production and the necessity of a finite-sized dislocation-free region in which a dislocation source may operate. Using a continuum theory of dislocation pileups, a closed form expression is obtained for the dependence of yield stress on grain size and source characteristics. The continuum model agrees closely with the corresponding discrete dislocation model. Second, a scaling theory describing the strength of lamellar materials is developed. The Hall-Petch relation is found to result from the similarity between dislocation densities of pileups of different lengths and under different applied stresses. For multilayers, the scaling theory predicts sigma y = KΛ--a + sigma0, where Λ is the compositional wavelength of the multilayer and a is a material dependent exponent. The scaling theory is then enlarged to incorporate parameters important to the operation of dislocation sources. The simulation of curvilinear dislocations, based on linear isotropic elasticity theory, includes self stress and dislocation-dislocation interactions. The operation stress of a Frank-Read source is found as a function of source size. Additionally, the plastic strain produced by a continuously operating source was

  12. Dislocation dynamics in multiwalled carbon nanotubes at high temperatures.

    PubMed

    Huang, J Y; Ding, F; Yakobson, B I

    2008-01-25

    Dislocation dynamics dictate the mechanical behavior of materials. Dislocations in periodic crystalline materials have been well documented. On the contrary, dislocations in cylindrical carbon nanotubes, particularly in multiwalled carbon nanotubes (MWCNTs), remain almost unexplored. Here we report that a room temperature 1/2<0001> sessile dislocation in a MWCNT becomes highly mobile, as characterized by its glide, climb, and the glide-climb interactions, at temperatures of about 2000 degrees C. The dislocation glide leads to the cross-linking of different shells; dislocation climb creates nanocracks; and the interaction of two 1/2<0001> dislocations creates kinks. We found that dislocation loops act as channels for mass transport. These dislocation dynamics are drastically different from that in conventional periodic crystalline materials due to the cylindrical, highly anisotropic structures of MWCNTs. PMID:18232998

  13. Bauschinger effect in thin metal films: Discrete dislocation dynamics study

    NASA Astrophysics Data System (ADS)

    Davoudi, Kamyar M.; Nicola, Lucia; Vlassak, Joost J.

    2014-01-01

    The effects of dislocation climb on plastic deformation during loading and unloading are studied using a two-dimensional discrete dislocation dynamics model. Simulations are performed for polycrystalline thin films passivated on both surfaces. Dislocation climb lowers the overall level of the stress inside thin films and reduces the work hardening rate. Climb decreases the density of dislocations in pile-ups and reduces back stresses. These factors result in a smaller Bauschinger effect on unloading compared to simulations without climb. As dislocations continue to climb at the onset of unloading and the dislocation density continues to increase, the initial unloading slope increases with decreasing unloading rate. Because climb disperses dislocations, fewer dislocations are annihilated during unloading, leading to a higher dislocation density at the end of the unloading step.

  14. Influence of dislocation and dislocation loop biases on microstructures simulated by rate equation cluster dynamics

    NASA Astrophysics Data System (ADS)

    Jourdan, T.

    2015-12-01

    Sensitivity of microstructures under irradiation to absorption biases of dislocations and dislocation loops is investigated by rate equation cluster dynamics (RECD). Contrary to standard rate theory which is often used to estimate sensitivity of cavity growth to biases, it is possible with RECD to quantify the effect of biases on nucleation, growth and coarsening of loops and cavities. For this purpose simple and accurate expressions for dislocation and dislocation loop biases are derived, based on finite element calculations. They are used in a RECD code to quantify the effect of biases on microstructures of austenitic steels irradiated with electrons. It is shown that biases have a strong influence not only on the loop and dislocation network evolutions, but also on cavity nucleation. Sensitivity to some other parameters of the model is also discussed.

  15. Large-diameter femoral heads in total hip arthroplasty: an evidence-based review.

    PubMed

    Banerjee, Samik; Pivec, Robert; Issa, Kimona; Kapadia, Bhaveen H; Khanuja, Harpal S; Mont, Michael A

    2014-11-01

    Recent advances in the wear characteristics and material properties of highly cross-linked polyethyl-ene and fourth-generation ceramic bearings have led to increasing use of large-diameter (≥ 36 mm) femoral heads in total hip arthroplasty (THA). In this article, we review the current concepts and principles behind use of large-diameter ceramic or cobalt-chromium femoral heads on polyethylene bearings in THA. We specifically review the biomechanics, some of the early concerns about polyethylene wear and rim fractures, recent improvements in material properties of polyethylene and ceramic bearings, dislocation rates, and clinical and functional outcomes of large-diameter heads in THA. Recent literature suggests that the incidence of dislocation has been substantially reduced because of improvements in jump distance and impingement-free range of motion with use of large-diameter heads. Limited evidence suggests excellent short-term and midterm clinical and functional outcomes with these heads. PMID:25379747

  16. 21 CFR 888.3360 - Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... uncemented prosthesis. 888.3360 Section 888.3360 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis is a device intended to be...

  17. 21 CFR 888.3360 - Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... uncemented prosthesis. 888.3360 Section 888.3360 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis is a device intended to be...

  18. Deciding to have knee or hip replacement

    MedlinePlus

    ... patientinstructions/000368.htm Deciding to have knee or hip replacement To use the sharing features on this page, ... make a decision. Who Benefits From Knee or hip Replacement Surgery? The most common reason to have a ...

  19. Risks of hip and knee replacement

    MedlinePlus

    ... is normal to lose blood during and after hip or knee replacement surgery. Some people need a blood transfusion during ... clot form are higher during and soon after hip or knee replacement surgery. Sitting or lying down for long periods ...

  20. Spontaneous modular femoral head dissociation complicating total hip arthroplasty.

    PubMed

    Talmo, Carl T; Sharp, Kinzie G; Malinowska, Magdalena; Bono, James V; Ward, Daniel M; LaReau, Justin

    2014-06-01

    Modular femoral heads have been used successfully for many years in total hip arthroplasty. Few complications have been reported for the modular Morse taper connection between the femoral head and trunnion of the stem in metal-on-polyethylene bearings. Although there has always been some concern over the potential for fretting, corrosion, and generation of particulate debris at the modular junction, this was not considered a significant clinical problem. More recently, concern has increased because fretting and corrosive debris have resulted in rare cases of pain, adverse local tissue reaction, pseudotumor, and osteolysis. Larger femoral heads, which have gained popularity in total hip arthroplasty, are suspected to increase the potential for local and systemic complications of fretting, corrosion, and generation of metal ions because of greater torque at the modular junction. A less common complication is dissociation of the modular femoral heads. Morse taper dissociation has been reported in the literature, mainly in association with a traumatic event, such as closed reduction of a dislocation or fatigue fracture of the femoral neck of a prosthesis. This report describes 3 cases of spontaneous dissociation of the modular prosthetic femoral head from the trunnion of the same tapered titanium stem because of fretting and wear of the Morse taper in a metal-on-polyethylene bearing. Continued clinical and scientific research on Morse taper junctions is warranted to identify and prioritize implant and surgical factors that lead to this and other types of trunnion failure to minimize complications associated with Morse taper junctions as hip implants and surgical techniques continue to evolve. PMID:24972443

  1. Metal ion levels and functional results after either resurfacing hip arthroplasty or conventional metal-on-metal hip arthroplasty

    PubMed Central

    2011-01-01

    Background Modern metal-on-metal hip resurfacing was introduced as a bone-preserving method of joint reconstruction for young and active patients; however, the large diameter of the bearing surfaces is of concern for potentially increased metal ion release. Patients and methods 71 patients (< 65 years old) were randomly assigned to receive either a resurfacing (R) hip arthroplasty (n = 38) or a conventional metal-on-metal (C) hip arthroplasty (n = 33). Functional outcomes were assessed preoperatively and at 6, 12, and 24 months. Cobalt and chromium blood levels were analyzed preoperatively and at 3, 6, 12, and 24 months. Results All functional outcome scores improved for both groups. At 12 and 24 months, the median UCLA activity score was 8 in the R patients and 7 in the C patients (p < 0.05). At 24 months, OHS was median 16 in C patients and 13 in R patients (p < 0.05). However, in spite of randomization, UCLA scores also appeared to be higher in R patients at baseline. Satisfaction was similar in both groups at 24 months. Cobalt concentrations were statistically significantly higher for R patients only at 3 and 6 months. Chromium levels remained significantly higher for R patients until 24 months. No pseudotumors were encountered in either group. One R patient was revised for early aseptic loosening and in 2 C patients a cup insert was exchanged for recurrent dislocation. Interpretation R patients scored higher on UCLA, OHS, and satisfaction at some time points; however, as for the UCLA, preoperative levels were already in favor of R. The differences, although statistically significant, were of minor clinical importance. Chromium blood levels were statistically significantly higher for R patients at all follow-up measurements, whereas for cobalt this was only observed up to 6 months. The true value of resurfacing hip arthroplasty over conventional metal-on-metal hip arthroplasty will be determined by longer follow-up and a possible shift of balance between their

  2. Cementless Hydroxyapatite Coated Hip Prostheses

    PubMed Central

    Herrera, Antonio; Mateo, Jesús; Gil-Albarova, Jorge; Lobo-Escolar, Antonio; Ibarz, Elena; Gabarre, Sergio; Más, Yolanda

    2015-01-01

    More than twenty years ago, hydroxyapatite (HA), calcium phosphate ceramics, was introduced as a coating for cementless hip prostheses. The choice of this ceramic is due to its composition being similar to organic apatite bone crystals. This ceramic is biocompatible, bioactive, and osteoconductive. These qualities facilitate the primary stability and osseointegration of implants. Our surgical experience includes the implantation of more than 4,000 cementless hydroxyapatite coated hip prostheses since 1990. The models implanted are coated with HA in the acetabulum and in the metaphyseal area of the stem. The results corresponding to survival and stability of implants were very satisfactory in the long-term. From our experience, HA-coated hip implants are a reliable alternative which can achieve long term survival, provided that certain requirements are met: good design selection, sound choice of bearing surfaces based on patient life expectancy, meticulous surgical technique, and indications based on adequate bone quality. PMID:25802848

  3. [An assistant artificial hip joint].

    PubMed

    Shi, Zhen-man; Chen, Jian-chang; Shi, Jiang; Chen, Wenhong; Zhang, Chunhao

    2002-01-01

    The assistant artificial hip joint (AAHJ) is a new impermanent hip support implanted in the body. It is used for treatment of ischemic necrosis of the femoral head at the early stage. It reserves the natural femoral head, increases its containment and decreases its load, thus makes the recovery of the necrosed femoral head. The AAHJ's moving axis center is the same as that of the femoral head. Therefore, the moving range of the hip joint is very close to the normal postoperatively. The patient can walk with loading in 3 weeks after the surgical operation, and can regain his (or her) daily work and life in 2 to 3 months of the operation. The AAHJ's structure is simple and the price is cheap. PMID:16104164

  4. Subspine Hip Impingement: An Unusual Cause of Hip Pain in an Elite Weightlifter.

    PubMed

    Nabhan, Dustin C; Moreau, William J; McNamara, Shannen C; Briggs, Karen K; Philippon, Marc J

    2016-01-01

    Anterior hip pain can be difficult to diagnose due to the many pathologies and overlapping pain patterns that exist in the hip region. Clinical findings of pain at the anterior inferior iliac spine with passive hip flexion, proximal quadriceps pain and weakness, and painful impingement tests of the hip may be indicative of subspine hip impingement. This report describes the diagnosis and treatment of anterior hip pain, including subspine impingement and femoroacetabular impingement in an elite weightlifter. This case also describes how with the correct diagnosis and treatment, the athlete returned to play to her previous level of sport 11 months after a complex hip injury. PMID:27618239

  5. Screw dislocations in GaN

    SciTech Connect

    Liliental-Weber, Zuzanna; Jasinski, Jacek B.; Washburn, Jack; O'Keefe, Michael A.

    2002-02-15

    GaN has received much attention over the past few years because of several new applications, including light emitting diodes, blue laser diodes and high-power microwave transistors. One of the biggest problems is a high density of structural defects, mostly dislocations, due to a lack of a suitable lattice-matched substrate since bulk GaN is difficult to grow in large sizes. Transmission Electron Microscopy (TEM) has been applied to study defects in plan-view and cross-sections on samples prepared by conventional techniques such as mechanical thinning and precision ion milling. The density of dislocations close to the sample surface of a 1 mm-thick HVPE sample was in the range of 3x109 cm-2. All three types of dislocations were present in these samples, and almost 50 percent were screw dislocations. Our studies suggest that the core structure of screw dislocations in the same material might differ when the material is grown by different methods.

  6. Glassy dislocation dynamics in colloidal dimer crystals

    NASA Astrophysics Data System (ADS)

    Gerbode, Sharon

    2012-02-01

    Dislocation mobility is central to both the mechanical response and the relaxation mechanisms of crystalline materials. Recent experiments have explored the role of novel particle anisotropies in affecting the rules of defect motion in crystals. ``Peanut-shaped'' colloidal dimer particles consisting of two connected spherical lobes form densely packed crystals in 2D. In these ``degenerate crystals,'' the particle lobes occupy triangular lattice sites while the particle axes are randomly oriented among the three crystalline directions. One consequence of the random orientations of the dimers is that dislocation glide is severely limited by certain particle arrangements in the degenerate crystals. Using optical tweezers to manipulate single lobe-sized spherical intruder particles, we locally deform the crystal, creating defects. During subsequent relaxation, the dislocations formed during the deformation leave the crystal grain, either via annihilation with other dislocations or by moving to a grain boundary. Interestingly, in large crystalline grains this dislocation relaxation occurs through a two-stage process reminiscent of slow relaxations in glassy systems, suggesting the novel concept that glassy phenomena may be introduced to certain kinds of colloidal crystals via simple anisotropic constituents.

  7. Isolated dorsal dislocation of the tarsal naviculum

    PubMed Central

    Hamdi, Kaziz; Hazem, Ben Ghozlen; Yadh, Zitoun; Faouzi, Abid

    2015-01-01

    Isolated dislocation of the tarsal naviculum is an unusual injury, scarcely reported in the literature. The naviculum is surrounded by the rigid bony and ligamentous support hence fracture dislocation is more common than isolated dislocation. The mechanism and treatment options remain unclear. In this case report, we describe a 31 year old man who sustained an isolated dorsal dislocation of the left tarsal naviculum, without fracture, when he was involved in a motor vehicle collision. The reported mechanism of the dislocation is a hyper plantar flexion force applied to the midfoot, resulting in a transient disruption of the ligamentous support of the naviculum bone, with dorsal displacement of the bone. The patient was treated with open reduction and Krischner-wire fixation of the navicular after the failure of closed reduction. The wires were removed after 6 weeks postoperatively. Physiotherapy for stiffness and midfoot pain was recommended for 2 months. At 6 months postoperatively, limping, midfoot pain and weakness were reported, no X-ray abnormalities were found. The patient returned to his obvious activities with a normal range of motion. PMID:26806978

  8. Dislocation dynamics in an anisotropic stripe pattern.

    PubMed

    Kamaga, Carina; Ibrahim, Fatima; Dennin, Michael

    2004-06-01

    The dynamics of dislocations confined to grain boundaries in a striped system are studied using electroconvection in the nematic liquid crystal N4. In electroconvection, a striped pattern of convection rolls forms for sufficiently high driving voltages. We consider the case of a rapid change in the voltage that takes the system from a uniform state to a state consisting of striped domains with two different wave vectors. The domains are separated by domain walls along one axis and a grain boundary of dislocations in the perpendicular direction. The pattern evolves through dislocation motion parallel to the domain walls. We report on features of the dislocation dynamics. The kinetics of the domain motion is quantified using three measures: dislocation density, average domain wall length, and total domain wall length per area. All three quantities exhibit behavior consistent with power-law evolution in time, with the defect density decaying as t(-1/3), the average domain wall length growing as t(1/3), and the total domain wall length decaying as t(-1/5). The two different exponents are indicative of the anisotropic growth of domains in the system. PMID:15244714

  9. Crack interaction with 3-D dislocation loops

    NASA Astrophysics Data System (ADS)

    Gao, Huajian

    CRACKS in a solid often interact with other crystal defects such as dislocation loops. The interaction effects are of 3-D character yet their analytical treatment has been mostly limited to the 2-D regime due to mathematical complications. This paper shows that distribution of the stress intensity factors along a crack front due to arbitrary dislocation loops may be expressed as simple line integrals along the loop contours. The method of analysis is based on the 3-D Bueckner-Rice weight function theory for elastic crack analysis. Our results have significantly simplified the calculations for 3-D dislocation loops produced in the plastic processes at the crack front due to highly concentrated crack tip stress fields. Examples for crack-tip 3-D loops and 2-D straight dislocations emerging from the crack tip are given to demonstrate applications of the derived formulae. The results are consistent with some previous analytical solutions existing in the literature. As further applications we also analyse straight dislocations that are parallel or perpendicular to the crack plane but are not parallel to the crack front.

  10. Search for dislocation free 4He crystals

    NASA Astrophysics Data System (ADS)

    Souris, Fabien; Fefferman, Andrew; Haziot, Ariel; Beamish, John; Balibar, Sebastien

    2014-03-01

    The elastic anomaly of 4He crystals is known to be a consequence of the motion of their dislocations. We have built an acoustic cell in order to grow and study crystals with the smallest possible density of dislocations. It has a polished inner surface to avoid pinning sites for the liquid-solid interface. Piezoelectric transducers are placed outside the cell volume, in order to drive and detect acoustical resonances through built-in copper membranes. We expect dislocation free crystals to behave rather differently from the usual ones (1,2). For example, they should not show any anomalous softening. Preliminary results show that crystals grown in this particular cell have longer dislocation lengths than in those studied in previous experiments (1,2). Centimeter long dislocations should resonate below 20 kHz. 1- A. Haziot et al., Phys. Rev. Lett. 110, 035301 (2013), Phys. Rev. B 87, 060509(R) (2013), and Phys. Rev. B 88, 014106 (2013). 2- A. D. Fefferman et al., submitted to Phys. Rev. B, Nov. 2013. ERC Grant AdG247258 SUPERSOLID and NSERC Canada.

  11. Preventing mechanical complications of hip spacer implantation: technical tips and pearls.

    PubMed

    Barreira, Pedro; Leite, Pedro; Neves, Pedro; Soares, Daniel; Sousa, Ricardo

    2015-06-01

    Periprosthetic joint infection is a frequent complication after total hip replacement. Two-stage exchange with the use of a temporary cement spacer is commonplace. Several complications are possible with its use. In addition to infection persistence, mechanical complications such as dislocation or fractures are among the most common. Several risk factors can and should be addressed during first stage or spacer implantation surgery in order to minimize complications. Technical aspects as well as practical tips and pearls to overcome common nuisances such as spacer instability or femoral and acetabular bone loss will be discussed. PMID:26280978

  12. High dislocation density of tin induced by electric current

    SciTech Connect

    Liao, Yi-Han; Liang, Chien-Lung; Lin, Kwang-Lung; Wu, Albert T.

    2015-12-15

    A dislocation density of as high as 10{sup 17} /m{sup 2} in a tin strip, as revealed by high resolution transmission electron microscope, was induced by current stressing at 6.5 x 10{sup 3} A/ cm{sup 2}. The dislocations exist in terms of dislocation line, dislocation loop, and dislocation aggregates. Electron Backscattered Diffraction images reflect that the high dislocation density induced the formation of low deflection angle subgrains, high deflection angle Widmanstätten grains, and recrystallization. The recrystallization gave rise to grain refining.

  13. [Hip fracture: call the geriatrician? ].

    PubMed

    Coutaz, M

    2014-11-01

    Hip fracture management by the geriatrician demands a close cooperation with orthopedic surgeons and a interdisciplinary approach with the implementation of protocole-driven care to standardize the care of most patients. From admission to discharge this orthogeriatric management is based on the comprehensive geriatric assessment to reduce the delays in surgery, the occurence of delirium or the most postoperative complications. This collaborative model of care seems to have the potential to improve function, admissions to nursing homes and mortality outcomes compared with usual care of geriatric patient with hip fracture. PMID:25536828

  14. Hip-Hop and the Academic Canon

    ERIC Educational Resources Information Center

    Abe, Daudi

    2009-01-01

    Over the last 30 years, the hip-hop movement has risen from the margins to become the preeminent force in US popular culture. In more recent times academics have begun to harness the power of hip-hop culture and use it as a means of infusing transformative knowledge into the mainstream academic discourse. On many college campuses, hip-hop's…

  15. 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

  16. Navigated Acetabular Cup Fixation for Acetabular Deformity or Revision Total Hip Arthroplasty

    PubMed Central

    Yoon, Jung-Ro; Yu, Jung Jin; Seo, Hyo-Sung

    2014-01-01

    Purpose To evaluate the usefulness of navigated acetabular cup fixation for total hip arthroplasty in patients with acetabular deformity or revision total hip arthroplasty. Materials and Methods This study enrolled 28 patients with at least 12 months' follow-up. The safe zone of the acetabular cup was defined as 40°±10°in inclination and 15°±10°in anteversion. The authors used the navigation and radiographic data to determine whether the acetabular cup was located within the safe zone or not. To evaluate the clinical outcomes, preoperative and last follow-up Harris hip scores were checked, and the occurrence of complications was evaluated. Results According to the navigation data, the mean inclination and anteversion were 38.5°±4.7°(range, 32°-50°) and 16.6°±4.0°(range, 8°-23°), respectively. According to the radiographic data the mean inclination and anteversion were 40.5°±4.6°(range, 32°-50°) and 19.4°±4.2°(range, 8°-25°), respectively. In both cases, all values were within the safe zone. Harris hip score was improved in all patients from preoperative 52.3±14.4 points (range, 29-87 points) to 88.0±9.0 points (range, 65-99 points) at the last follow-up. There was no dislocation or loosening of both cases. Conclusion Navigated acetabular cup fixation is a useful technique for total hip arthroplasty in patients with acetabular deformity or revision total hip arthroplasty because it prevents the malposition and related complications.

  17. A comparison of ketamine versus etomidate for procedural sedation for the reduction of large joint dislocations

    PubMed Central

    Salen, Philip; Grossman, Michelle; Grossman, Michael; Milazzo, Anthony; Stoltzfus, Jill

    2016-01-01

    Study Objectives: Ketamine and etomidate are used for procedural sedation (PS) to facilitate the performance of painful procedures. We hypothesized that ketamine produces adequate and comparable sedation conditions for dislocated large joint reduction when compared to etomidate and results in fewer adverse events. Methods: This Institutional Review Board approved prospective trial compared a convenience sample of subjects, who were randomized to receive either ketamine or etomidate for PS to facilitate reduction of large joint dislocations. Following informed consent, subjects were assigned via a computer-generated algorithm to receive either etomidate (0.1 mg/kg) or ketamine (0.5 mg/kg) intravenously; if PS was not sufficient, subjects received repeat doses of etomidate or ketamine until adequate PS was achieved. The protocol's primary endpoint was a successful reduction of dislocated, large joints. Secondary endpoints included alteration in blood pressure, vomiting, recovery agitation, hypersalivation, laryngospasm, myoclonus, hypoxia, airway assistance with chin lift or jaw thrust, bag-valve-mask ventilation, endotracheal intubation, utilization of additional doses of ketamine or etomidate, and recovery time from sedation. Results: Total enrollment was eighty subjects, 46 in the ketamine cohort and 34 in the etomidate cohort. The two PS groups were comparable in terms of gender, age, and weight. There was no significant difference in the primary endpoint of large joint dislocation reduction between the ketamine and etomidate cohorts (46/46, 100%; 32/34, 94.1%; P – 0.1). Shoulder, hip, and ankle joints account for the majority of joint reductions in this trial. Titration of PS was necessary for almost half of each cohort as evidenced by the utilization of additional dosages of the sedative agents: ketamine (22/46, 47.8%) and etomidate (14/34, 41.2%; P – 0.56). Among secondary outcome variables, significant differences between ketamine and etomidate cohorts

  18. Feasibility of Arthroscopic Placement of Autologous Matrix-Induced Chondrogenesis Grafts in the Cadaver Hip Joint

    PubMed Central

    Thorey, Fritz; Budde, Stefan; Ezechieli, Marco; Albrecht, Urs Vito; Ettinger, Max

    2013-01-01

    An assortment of clinical trials have been done presenting the effectiveness of autologous matrix-induced chondrogenesis (AMIC) for the regeneration of chondral leasions. The purpose of the study was to underline the accessability of the acetabulum and the femoral head through the known portals and prove i) the feasibility of placing the AMIC in the different zones of the hip joint and ii) check for dislocation after joint movement. Six human cadavers underwent hip arthroscopy on both hips. Two chondral lesions were set on each femoral head and two in the acetabulum to evaluate a total of 48 defects. After microfracturing an autologous matrix-induced chondrogenesis graft was placed on these lesions arthroscopically. After repeated joint movement the dislocation of the graft was checked. It was possible to place the AMIC graft in all 48 chondral lesions. The time needed for placing the graft was 8±2.9 minutes. A trend of time reduction could be detected throughout this study as the surgeon gained more experience. For the femoral head, after twenty cycles of joint movement 18/24 spots showed no displacement, 4/24 showed minor displacement (<3 mm) and 2/24 showed major displacement (>3 mm). None showed total displacement. For the acetabulum 22/24 spots showed no displacement and 2/24 showed minor displacement. A combined microfracturing and placing of an AMIC graft of focal chondral lesions of the hip joint can be done arthroscopically. Prospective randomized in vivo studies should compare the results of arthroscopilally placed AMIC grafts with microfracturing and microfracturing alone. PMID:24191186

  19. Hip Joint Replacement Using Monofilament Polypropylene Surgical Mesh: An Animal Model

    PubMed Central

    Białecki, Jacek; Klimowicz-Bodys, Małgorzata Dorota; Wierzchoś, Edward; Kołomecki, Krzysztof

    2014-01-01

    Hip joint dysplasia is a deformation of the articular elements (pelvic acetabulum, head of the femur, and/or ligament of the head of the femur) leading to laxity of the hip components and dislocation of the femoral head from the pelvic acetabulum. Diagnosis is based on symptoms observed during clinical and radiological examinations. There are two treatment options: conservative and surgical. The classic surgical procedures are juvenile pubic symphysiodesis (JPS), triple pelvic osteotomy (TPO), total hip replacement (THR), and femoral head and neck resection (FHNE). The aim of this experiment was to present an original technique of filling the acetabulum with a polypropylene implant, resting the femoral neck directly on the mesh. The experiment was performed on eight sheep. The clinical value of the new surgical technique was evaluated using clinical, radiological, and histological methods. This technique helps decrease the loss of limb length by supporting the femoral neck on the mesh equivalent to the femoral head. It also reduces joint pain and leads to the formation of stable and mobile pseudarthrosis. The mesh manifested osteoprotective properties and enabled the formation of a stiff-elastic connection within the hip joint. The method is very cost-effective and the technique itself is simple to perform. PMID:24987672

  20. Hip joint replacement using monofilament polypropylene surgical mesh: an animal model.

    PubMed

    Białecki, Jacek; Majchrzycki, Marian; Szymczak, Antoni; Klimowicz-Bodys, Małgorzata Dorota; Wierzchoś, Edward; Kołomecki, Krzysztof

    2014-01-01

    Hip joint dysplasia is a deformation of the articular elements (pelvic acetabulum, head of the femur, and/or ligament of the head of the femur) leading to laxity of the hip components and dislocation of the femoral head from the pelvic acetabulum. Diagnosis is based on symptoms observed during clinical and radiological examinations. There are two treatment options: conservative and surgical. The classic surgical procedures are juvenile pubic symphysiodesis (JPS), triple pelvic osteotomy (TPO), total hip replacement (THR), and femoral head and neck resection (FHNE). The aim of this experiment was to present an original technique of filling the acetabulum with a polypropylene implant, resting the femoral neck directly on the mesh. The experiment was performed on eight sheep. The clinical value of the new surgical technique was evaluated using clinical, radiological, and histological methods. This technique helps decrease the loss of limb length by supporting the femoral neck on the mesh equivalent to the femoral head. It also reduces joint pain and leads to the formation of stable and mobile pseudarthrosis. The mesh manifested osteoprotective properties and enabled the formation of a stiff-elastic connection within the hip joint. The method is very cost-effective and the technique itself is simple to perform. PMID:24987672

  1. Growth characteristics of the fetal ligament of the head of femur: significance in congenital hip disease.

    PubMed Central

    Walker, J. M.

    1980-01-01

    Measurement of the length and width of the ligament of the head of femur (ligamentum teres) in 140 normal human fetuses between 12 weeks and term provides limits for growth changes in this structure. These observations provide no morphological evidence of a significant difference between males and females, or between the right and left sides, to explain the female and left hip preponderance reported in congenital hip disease. The ligament is shown to be variable in length, width, and shape, and it is not a distinctly linear structure through linearity may increase with age. Tests of femoral head mobility support the opinion that this ligament must play a role in fetal and neonatal hip joint stability. Weak correlation only was demonstrated between the ligament variables and acetabular depth, which suggests that ligament shape and socket shape are not closely related. Comparison of measurements from normal and 12 dysplastic or subluxated joints provides no evidence to support previous observations that this structure is unusually long in abnormal hip joints which are not frankly dislocated. Images FIG. 1 PMID:7445537

  2. Electron paramagnetic resonance at dislocations in germanium

    SciTech Connect

    Pakulis, E.J.

    1982-06-01

    The first observation of the paramagnetic resonance of electrons at dislocations in germanium single crystals is reported. Under subband gap optical excitation, two sets of lines are detected: four lines about the <111> axes with g/sub perpendicular to/ = 0.34 and g/sub parallel/ = 1.94, and 24 lines with g/sub perpendicular to/ = 0.73 and g/sub parallel/ = 1.89 about <111> axes with the six-fold 1.2/sup 0/ distortion. This represents the first measurement of the disortion angle of a dislocation dangling bond. The possibility that the distortion results from a Peierls transition along the dislocation line is discussed.

  3. Crack Tip Dislocation Nucleation in FCC Solids

    NASA Astrophysics Data System (ADS)

    Knap, J.; Sieradzki, K.

    1999-02-01

    We present results of molecular dynamic simulations aimed at examining crack tip dislocation emission in fcc solids. The results are analyzed in terms of recent continuum formulations of this problem. In mode II, Au, Pd, and Pt displayed a new unanticipated mechanism of crack tip dislocation emission involving the creation of a pair of Shockley partials on a slip plane one plane below the crack plane. In mode I, for all the materials examined, Rice's continuum formulation [J. Mech. Phys. Solids 40, 239 (1992)] underestimated the stress intensity for dislocation emission by almost a factor of 2. Surface stress corrections to the emission criterion brought the agreement between continuum predictions and simulations to within 20%.

  4. Brachial Artery Injury Accompanying Closed Elbow Dislocations

    PubMed Central

    Harnarayan, Patrick; Cawich, Shamir O.; Harnanan, Dave; Budhooram, Steve

    2014-01-01

    Introduction Brachial artery injuries from elbow dislocations are uncommon, but they may lead to disastrous consequences if the diagnosis is delayed. Presentation of case We report a case of a patient who sustained a fall onto the elbow, with dislocation and brachial artery injury, despite an ipsilateral radial pulse being palpable. Discussion Clinicians should maintain a high index of suspicion for brachial injury when patients present with a fall onto the elbow coupled with signs suggestive of fracture-dislocation, nerve injury and/or signs of limb ischemia. Frank ischamia, however, is uncommon as there is a rich collateral anastomosis in the upper limb. Conclusion A high index of suspicion should be maintained in order to make the diagnosis early. Exploration with excision of the injured segment and reverse vein interposition grafting is the treatment of choice in these cases. PMID:25644552

  5. Molecular Mechanisms of HipA Mediated Multidrug Tolerance and its Neutralization by HipB

    PubMed Central

    Schumacher, Maria A.; Piro, Kevin M.; Xu, Weijun; Hansen, Sonja; Lewis, Kim; Brennan, Richard G.

    2009-01-01

    Summary Bacterial multidrug tolerance is largely responsible for the inability of antibiotics to eradicate infections and is caused by a small population of dormant bacteria called persisters. HipA is a critical Escherichia coli persistence factor that is normally neutralized by HipB, a transcription repressor, which also regulates hipBA expression. Here we report multiple structures of HipA and a HipA-HipB-DNA complex. HipA has a eukaryotic Ser/Thr kinase-like fold and can phosphorylate the translation factor, EF-Tu, suggesting a persistence mechanism via cell stasis. The HipA-HipB-DNA structure reveals the HipB-operator binding mechanism, ~70° DNA bending and unexpected HipA-DNA contacts. Dimeric HipB interacts with two HipA molecules to inhibit its kinase activity through sequestration and conformational inactivation. Combined, these studies suggest mechanisms for HipA-mediated persistence and its neutralization by HipB. PMID:19150849

  6. A preliminary investigation of dislocation cell structure formation in metals using continuum dislocation dynamics

    NASA Astrophysics Data System (ADS)

    Xia, S. X.; El-Azab, A.

    2015-08-01

    A continuum dislocation dynamics model capable of capturing the cellular arrangements of dislocations in deformed crystals is presented. A small strain formulation of the model is given, followed by sample results of stress-strain behaviour, dislocation density evolution, dislocation cell pattern, lattice rotation, and geometrically necessary dislocation density and strain energy density distributions. An important finding of the current work is that dislocations form patterns under all circumstances due to their long range interactions. It is found, however, that the famous cell structure pattern forms when cross slip is activated. It is also found that cells are 3D sub-regions surrounded by dislocations walls in all directions, and they form, disappear, and reappear as a result of the motion of cell walls and formation of new walls by cross slip. It is further found that the average cell size is connected with the applied resolved shear stress according to the similitude principle observed in related experiments. The importance of these results is briefly discussed in the context of recrystallization.

  7. Dislocation dynamics in SiGe alloys

    NASA Astrophysics Data System (ADS)

    Yonenaga, I.

    2013-11-01

    The dislocation velocities and mechanical strength of bulk crystals of SixGe1-x alloys grown by the Czochralski method have been investigated by the etch pit technique and compressive deformation tests, respectively. Velocity of dislocations in the SiGe alloys of the composition range 0.004 < x < 0.08 decreases monotonically with an increase in Si content at temperature 450-700°C and under stress 3-24MPa. In contrast, velocity of dislocations in the composition range 0.92 < x < 1 first increases, then decreases and again increases with a decrease in Si content at temperature 750-850°C and under stress 3-30MPa. The velocity of dislocations was quantitatively evaluated as functions of stress and temperature. Stress-strain behaviour in the yield region of the SiGe alloys of composition 0 < x < 0.4 is similar to that of Ge at temperatures lower than about 600°C. However, the yield stress becomes temperature-insensitive at high temperatures and increases with increasing Si content. The stress-strain curves of the SiGe alloys of composition 0.95 < x < 1 are similar to those of pure Si at temperatures 800-1000°C and the yield stress increases with decreasing Si content down to x = 0.95. The yield stress of the SiGe alloys is dependent on the composition, being proportional to x(1-x), showing a maximum around x ≈ 0.5. Built-in stress fields related to local fluctuation of the alloy composition and the dynamic development of a solute atmosphere around the dislocations, may suppress the activities of dislocations and lead to the hardening of SiGe alloys.

  8. High-temperature discrete dislocation plasticity

    NASA Astrophysics Data System (ADS)

    Keralavarma, S. M.; Benzerga, A. A.

    2015-09-01

    A framework for solving problems of dislocation-mediated plasticity coupled with point-defect diffusion is presented. The dislocations are modeled as line singularities embedded in a linear elastic medium while the point defects are represented by a concentration field as in continuum diffusion theory. Plastic flow arises due to the collective motion of a large number of dislocations. Both conservative (glide) and nonconservative (diffusion-mediated climb) motions are accounted for. Time scale separation is contingent upon the existence of quasi-equilibrium dislocation configurations. A variational principle is used to derive the coupled governing equations for point-defect diffusion and dislocation climb. Superposition is used to obtain the mechanical fields in terms of the infinite-medium discrete dislocation fields and an image field that enforces the boundary conditions while the point-defect concentration is obtained by solving the stress-dependent diffusion equations on the same finite-element grid. Core-level boundary conditions for the concentration field are avoided by invoking an approximate, yet robust kinetic law. Aspects of the formulation are general but its implementation in a simple plane strain model enables the modeling of high-temperature phenomena such as creep, recovery and relaxation in crystalline materials. With emphasis laid on lattice vacancies, the creep response of planar single crystals in simple tension emerges as a natural outcome in the simulations. A large number of boundary-value problem solutions are obtained which depict transitions from diffusional to power-law creep, in keeping with long-standing phenomenological theories of creep. In addition, some unique experimental aspects of creep in small scale specimens are also reproduced in the simulations.

  9. Geometry of dislocated de Broglie waves

    SciTech Connect

    Holland, P.R.

    1987-04-01

    The geometrical structures implicit in the de Broglie waves associated with a relativistic charged scalar quantum mechanical particle in an external field are analyzed by employing the ray concept of the causal interpretation. It is shown how an osculating Finslerian metric tensor, a torsion tensor, and a tetrad field define respectively the strain, the dislocation density, and the Burgers vector in the natural state of the wave, which is a non-Riemannian space of distant parallelism. A quantum torque determined by the quantum potential is introduced and the example of a screw dislocated wave is discussed.

  10. Suppressing dislocations in normalized hypercubic smearing

    NASA Astrophysics Data System (ADS)

    DeGrand, Thomas; Shamir, Yigal; Svetitsky, Benjamin

    2014-09-01

    Normalized hypercubic smearing improves the behavior of dynamical Wilson-clover fermions, but has the unwanted side effect that it can occasionally produce spikes in the fermion force. These spikes originate in the chain rule connecting the derivative with respect to the smeared links to the derivative with respect to the dynamical links, and are associated with the presence of dislocations in the dynamical gauge field. We propose and study an action designed to suppress these dislocations. We present evidence for improved performance of the hybrid Monte Carlo algorithm. A side benefit is improvement in the properties of valence chiral fermions.

  11. Formation and structure of misfit dislocations

    NASA Astrophysics Data System (ADS)

    Nandedkar, A. S.; Srinivasan, G. R.; Murthy, C. S.

    1991-03-01

    We report here theoretical observations of the evolution of core structure of well-defined misfit dislocations arising from the spontaneous decomposition of highly strained coherent interfaces in a fcc bicrystal. We use a finely stepped energy-minimization technique and Lennard-Jones pair potential, which allowed Burgers-circuit construction and core-structure analysis. Simulations were made for (111) and (001) interfaces, which produced 60° and edge dislocations, respectively. The atomic configurations produced were consistent with those expected from the elasticity theory.

  12. Rotator Cuff Tear Consequent to Glenohumeral Dislocation.

    PubMed

    Gilotra, Mohit N; Christian, Matthew W; Lovering, Richard M

    2016-08-01

    The patient was a 21-year-old collegiate running back who was tackled during a football game and sustained a posterior glenohumeral dislocation. He was referred to an orthopaedist and presented 3 weeks after the injury, and, following examination, further imaging was ordered by the orthopaedist due to rotator cuff weakness. Magnetic resonance imaging showed a complete tear of the supraspinatus and infraspinatus, as well as a posterior Bankart lesion, a subscapularis tear, and a dislocation of the biceps long head tendon into the reverse Hill-Sachs lesion. J Orthop Sports Phys Ther 2016;46(8):708. doi:10.2519/jospt.2016.0413. PMID:27477475

  13. Hip pain and childhood malignancy.

    PubMed

    Wong, M; Chung, C H; Ngai, W K

    2002-12-01

    In children, neuroblastoma can mimic various orthopaedic pathologies and this may create difficulties for doctors in reaching the correct diagnosis. Stage IV neuroblastoma was initially diagnosed as transient synovitis in this case report of a 7-year-old girl presenting with hip and low back pain. PMID:12459605

  14. Hip-Hop Pop Art

    ERIC Educational Resources Information Center

    Talley, Clarence, Sr.

    2011-01-01

    Art has a way of helping students better understand and appreciate the world around them, particularly the things that are most important to them. Hip hop is one of those generational genres that capture the attention of young students like few other things do. Drawing on this genre to get students to create art is an excellent way to demonstrate…

  15. Neurovascular Injury in Hip Arthroplasty

    PubMed Central

    2014-01-01

    Neurological and vascular complications following hip arthroplasty are uncommon, and their impact ranges from transient and trivial to permanent and devastating. The proximity of neural and vascular structures makes any operation on the hip potentially hazardous. Direct or indirect injuries of these structures may occur during operative exposure and subsequent procedures. Thus, complete awareness of the anatomy of the pelvis and proximal femur is required. Peripheral nerve injuries can involve either distant sites or nerves in the immediate vicinity of the hip joint. Sciatic nerve injury is the most common nerve injury following total hip arthroplasty. Femoral nerve injury is much less common and is associated with an anterior approach. Its diagnosis is often delayed, but the prognosis is generally better than with sciatic nerve injury. The superior gluteal nerve is at risk during the direct lateral approach. Obturator nerve injury is the least common type of injury and has the least functional consequences. Vascular injuries are less common but more immediately life threatening. The mechanisms of vascular injury include occlusion associated with preexisting peripheral vascular disease and vascular injury during removal of cement during screw fixation of acetabular components, cages, or structural grafts. It is critical to avoid the anterior quadrants for acetabular screw fixation. All acetabular and femoral defects should be bone-grafted to avoid inadvertent cement migration. Following these guidelines, surgeons should be able to offer the most appropriate treatment and counseling to the patients.

  16. Changes in the Burgers Vector of Perfect Dislocation Loops without Contact with the External Dislocations

    SciTech Connect

    Arakawa, K.; Hatanaka, M.; Mori, H.; Kuramoto, E.; Ono, K.

    2006-03-31

    We report the observations of a new type of changing process in the Burgers vector of dislocations by in situ transmission electron microscopy. Small interstitial-type perfect dislocation loops in bcc iron with diameters less than approximately 50 nm are transformed from a 1/2<111> loop to another 1/2<111> one or an energetically unfavorable <100> one; furthermore, a <100> loop is transformed to a 1/2<111> one. These transformations occurred on high-energy electron irradiation or simple heating without contact with external dislocations. The origin of these phenomena is discussed.

  17. A model for nucleation of tin whisker through dislocation behavior

    NASA Astrophysics Data System (ADS)

    Nakai, K.; Sakamoto, T.; Kobayashi, S.; Takamizawa, M.; Murakami, K.; Hino, M.

    2009-05-01

    A model for the nucleation and growth processes of Sn whisker is offered. High density of localized screw dislocations by deformation form the dense spiral steps of atomic scale on Sn surface. The spiral steps would induce the nucleation of Sn whisker. Edge dislocations localized at the same region where dense screw dislocations exist supply Sn atoms to the Sn whisker through pipe diffusion. Both screw and edge dislocations would bend along almost one direction, namely, to relax the external shear stress. The image force also helps to bend the dislocations perpendicular to the whisker side-surface. The bending of dislocations at root of whisker leads the bend of whisker. The pipe diffusion of Sn atoms through edge dislocations from bulk Sn toward whisker is suppressed at the bent part of edge dislocation, resulting in release of Sn atoms inside whisker and leading to the growth of whisker near its root.

  18. Continuum dislocation dynamics: Towards a physical theory of crystal plasticity

    NASA Astrophysics Data System (ADS)

    Hochrainer, Thomas; Sandfeld, Stefan; Zaiser, Michael; Gumbsch, Peter

    2014-02-01

    The plastic deformation of metals is the result of the motion and interaction of dislocations, line defects of the crystalline structure. Continuum models of plasticity, however, remain largely phenomenological to date, usually do not consider dislocation motion, and fail when materials behavior becomes size dependent. In this work we present a novel plasticity theory based on systematic physical averages of the kinematics and dynamics of dislocation systems. We demonstrate that this theory can predict microstructure evolution and size effects in accordance with experiments and discrete dislocation simulations. The theory is based on only four internal variables per slip system and features physical boundary conditions, dislocation pile ups, dislocation curvature, dislocation multiplication and dislocation loss. The presented theory therefore marks a major step towards a physically based theory of crystal plasticity.

  19. Scale-free phase field theory of dislocations.

    PubMed

    Groma, István; Vandrus, Zoltán; Ispánovity, Péter Dusán

    2015-01-01

    According to recent experimental and numerical investigations, if a characteristic length (such as grain size) of a specimen is in the submicron size regime, several new interesting phenomena emerge during the deformation. Since in such systems boundaries play a crucial role, to model the plastic response it is crucial to determine the dislocation distribution near the boundaries. In this Letter, a phase-field-type continuum theory of the time evolution of an ensemble of parallel edge dislocations with identical Burgers vectors, corresponding to the dislocation geometry near internal boundaries, is presented. Since the dislocation-dislocation interaction is scale free (1/r), apart from the average dislocation spacing the theory cannot contain any length scale parameter. As shown, the continuum theory suggested is able to recover the dislocation distribution near boundaries obtained by discrete dislocation dynamics simulations. PMID:25615479

  20. Scale-Free Phase Field Theory of Dislocations

    NASA Astrophysics Data System (ADS)

    Groma, István; Vandrus, Zoltán; Ispánovity, Péter Dusán

    2015-01-01

    According to recent experimental and numerical investigations, if a characteristic length (such as grain size) of a specimen is in the submicron size regime, several new interesting phenomena emerge during the deformation. Since in such systems boundaries play a crucial role, to model the plastic response it is crucial to determine the dislocation distribution near the boundaries. In this Letter, a phase-field-type continuum theory of the time evolution of an ensemble of parallel edge dislocations with identical Burgers vectors, corresponding to the dislocation geometry near internal boundaries, is presented. Since the dislocation-dislocation interaction is scale free (1 /r ), apart from the average dislocation spacing the theory cannot contain any length scale parameter. As shown, the continuum theory suggested is able to recover the dislocation distribution near boundaries obtained by discrete dislocation dynamics simulations.

  1. Molecular dynamics simulations of dislocation instability in a stress gradient

    NASA Astrophysics Data System (ADS)

    Li, Ming; Selinger, Robin L.

    2003-04-01

    We present simulation studies of a morphological instability arising in dislocation dynamics. When an initially straight dislocation line is driven by a stress whose magnitude grows along the direction of dislocation motion, vibrational modes of the dislocation line with wavelength above a threshold value become linearly unstable. Molecular dynamics simulation studies of screw dislocations in Al demonstrate the onset of the instability during dislocation pair annihilation and annihilation at a crack tip. The wavelength of the unstable vibrational mode observed in each case agrees with the predictions of theoretical analysis. We discuss the role of temperature in nucleating the instability and speculate about how instabilities in dislocation motion could affect the density of threading dislocations during growth of heteroepitaxial thin films.

  2. Determination of the inhomogeneous dislocation density in a crystallographic texture

    SciTech Connect

    Satdarova, F. F.; Kozlov, D. A.

    2007-03-15

    Diffraction analysis of the mixed dislocation structure of a polycrystal with an orthorhombic texture is reported. A significant difference in the dislocation densities in the texture components of cold-deformed low-carbon steel has been revealed.

  3. Sports hip injuries: assessment and management.

    PubMed

    Kelly, Bryan T; Maak, Travis G; Larson, Christopher M; Bedi, Asheesh; Zaltz, Ira

    2013-01-01

    Over the past 10 years, the understanding, assessment, and management of hip pain and injuries in the athlete have improved. Traditionally, the evaluation of hip pain and injuries was limited to obvious disorders, such as hip arthritis and fractures, or disorders that were previously considered to be simply soft-tissue strains and contusions, such as groin pulls, hip pointers, and bursitis. Two parallel tracks of progress have improved understanding of the complexities of hip joint athletic injuries and the biomechanical basis of early hip disease. In the field of sports medicine, improved diagnostic skills now allow better interpretation of debilitating intra-articular hip disorders and their effects on core performance. In the field of hip preservation, there has been an evolution in understanding the effects of biomechanical mismatches between the femoral head and the acetabulum on the development of early hip damage, injury, and arthritis. The integration of these two parallel fields has accelerated the understanding of the importance of hip biomechanics and early hip injury in human performance and function. PMID:23395055

  4. Hip Imaging in Athletes: Sports Imaging Series.

    PubMed

    Agten, Christoph A; Sutter, Reto; Buck, Florian M; Pfirrmann, Christian W A

    2016-08-01

    Hip or groin pain in athletes is common and clinical presentation is often nonspecific. Imaging is a very important diagnostic step in the work-up of athletes with hip pain. This review article provides an overview on hip biomechanics and discusses strategies for hip imaging modalities such as radiography, ultrasonography, computed tomography, and magnetic resonance (MR) imaging (MR arthrography and traction MR arthrography). The authors explain current concepts of femoroacetabular impingement and the problem of high prevalence of cam- and pincer-type morphology in asymptomatic persons. With the main focus on MR imaging, the authors present abnormalities of the hip joint and the surrounding soft tissues that can occur in athletes: intraarticular and extraarticular hip impingement syndromes, labral and cartilage disease, microinstability of the hip, myotendinous injuries, and athletic pubalgia. (©) RSNA, 2016. PMID:27429142

  5. Biotribology of artificial hip joints

    PubMed Central

    Di Puccio, Francesca; Mattei, Lorenza

    2015-01-01

    Hip arthroplasty can be considered one of the major successes of orthopedic surgery, with more than 350000 replacements performed every year in the United States with a constantly increasing rate. The main limitations to the lifespan of these devices are due to tribological aspects, in particular the wear of mating surfaces, which implies a loss of matter and modification of surface geometry. However, wear is a complex phenomenon, also involving lubrication and friction. The present paper deals with the tribological performance of hip implants and is organized in to three main sections. Firstly, the basic elements of tribology are presented, from contact mechanics of ball-in-socket joints to ultra high molecular weight polyethylene wear laws. Some fundamental equations are also reported, with the aim of providing the reader with some simple tools for tribological investigations. In the second section, the focus moves to artificial hip joints, defining materials and geometrical properties and discussing their friction, lubrication and wear characteristics. In particular, the features of different couplings, from metal-on-plastic to metal-on-metal and ceramic-on-ceramic, are discussed as well as the role of the head radius and clearance. How friction, lubrication and wear are interconnected and most of all how they are specific for each loading and kinematic condition is highlighted. Thus, the significant differences in patients and their lifestyles account for the high dispersion of clinical data. Furthermore, such consideration has raised a new discussion on the most suitable in vitro tests for hip implants as simplified gait cycles can be too far from effective implant working conditions. In the third section, the trends of hip implants in the years from 2003 to 2012 provided by the National Joint Registry of England, Wales and Northern Ireland are summarized and commented on in a discussion. PMID:25621213

  6. Dislocation dynamics in Rayleigh-Bénard convection.

    PubMed

    Walter, Th; Pesch, W; Bodenschatz, E

    2004-09-01

    Theoretical results on the dynamics of dislocations in Rayleigh-Bénard convection are reported both for a Swift-Hohenberg model and the Oberbeck-Boussinesq equations. For intermediate Prandtl numbers the motion of dislocations is found to be driven by the superposition of two independent contributions: (i) the Peach-Koehler force and (ii) an advection force on the dislocation core by its self-generated mean flow. Their competition allows to explain the experimentally observed bound dislocation pairs. PMID:15447003

  7. Frontal plane kinematics of the hip during running: Are they related to hip anatomy and strength?

    PubMed

    Baggaley, Michael; Noehren, Brian; Clasey, Jody L; Shapiro, Robert; Pohl, Michael B

    2015-10-01

    Excessive hip adduction has been associated with a number of lower extremity overuse running injuries. The excessive motion has been suggested to be the result of reduced strength of the hip abductor musculature. Hip anatomical alignment has been postulated to influence hip abduction (HABD) strength and thus may impact hip adduction during running. The purpose of this study was to investigate the relationship between hip anatomy, HABD strength, and frontal plane kinematics during running. Peak isometric HABD strength, 3D lower extremity kinematics during running, femoral neck-shaft angle (NSA), and pelvis width-femur length (PW-FL) ratio were recorded for 25 female subjects. Pearson correlations (p<0.05) were performed between variables. A fair relationship was observed between femoral NSA and HABD strength (r=-0.47, p=0.02) where an increased NSA was associated with reduced HABD strength. No relationship was observed between HABD strength and hip adduction during running. None of the anatomical measurements, NSA or PW-FL, were associated with hip adduction during running. Deviations in the femoral NSA have a limited ability to influence peak isometric hip abduction strength or frontal plane hip kinematics during running. Hip abduction strength does also not appear to be linked with changes in hip kinematics. These findings in healthy individuals question whether excessive hip adduction typically seen in female runners with overuse injuries is caused by deviations in hip abduction strength or anatomical structure. PMID:26364243

  8. An Acoustic Profile of Right-Dislocations in French.

    ERIC Educational Resources Information Center

    Ashby, William J.

    1994-01-01

    Provides an acoustic profile of the prosody of right-dislocations in French, using the CECIL computer hardware and software package to analyze 28 right-dislocations occurring in a corpus of natural French discourse. It was found that, although right-dislocations appear to fulfill various functional roles in discourse, no correlation appears…

  9. On onsagers principle, dislocation motion and hydrogen embrittlement

    NASA Technical Reports Server (NTRS)

    Louthan, M. R., Jr.; Mcnitt, R. P.

    1976-01-01

    Onsager's reciprocal relationships from the linear theory of irreversible thermodynamics are applied to hydrogen - dislocation interactions. Existing experimental evidence shows that dislocation motion causes localized hydrogen accumulation; thus, from the Onsager principle, localized hydrogen accumulations will affect dislocation motion and therefore the properties of metals and alloys exposed to hydrogen environments.

  10. The Perceptions of Dislocated Workers under the Workforce Investment Act

    ERIC Educational Resources Information Center

    Wilson, Michael S.; Brown, James M.

    2012-01-01

    This descriptive qualitative case study investigated the perceptions of dislocated workers offered program services through the Workforce Investment Act's (WIA) Dislocated Worker program in Minnesota. This research focused on recently dislocated workers who lost their jobs through no fault of their own and hence were eligible for unemployment…

  11. Metatarsal Shaft Fracture with Associated Metatarsophalangeal Joint Dislocation.

    PubMed

    Tung, Taranjit Singh

    2016-01-01

    Metatarsophalangeal joint dislocations of lesser toes are often seen in the setting of severe claw toes. Traumatic irreducible dislocations have been reported in rare cases following both low-energy and high-energy injuries to the forefoot. In this case report, I present a previously unreported association of a metatarsal shaft fracture with metatarsophalangeal joint dislocation of a lesser toe. PMID:27597914

  12. Metatarsal Shaft Fracture with Associated Metatarsophalangeal Joint Dislocation

    PubMed Central

    2016-01-01

    Metatarsophalangeal joint dislocations of lesser toes are often seen in the setting of severe claw toes. Traumatic irreducible dislocations have been reported in rare cases following both low-energy and high-energy injuries to the forefoot. In this case report, I present a previously unreported association of a metatarsal shaft fracture with metatarsophalangeal joint dislocation of a lesser toe. PMID:27597914

  13. Dislocation core fields and forces in FCC metals

    SciTech Connect

    Henager, Charles H.; Hoagland, Richard G.

    2004-04-01

    Atomistic models were used to obtain dislocation core fields for edge, screw, and mixed dislocations in Al and Cu using EAM. Core fields are analyzed using a line force dipole representation, with dilatant and dipole terms. The core field contribution to the force between dislocations is shown to be significant for interactions within 50b.

  14. Assessment of hardening due to dislocation loops in bcc iron: Overview and analysis of atomistic simulations for edge dislocations

    NASA Astrophysics Data System (ADS)

    Bonny, G.; Terentyev, D.; Elena, J.; Zinovev, A.; Minov, B.; Zhurkin, E. E.

    2016-05-01

    Upon irradiation, iron based steels used for nuclear applications contain dislocation loops of both < 100 > and ½ < 111 > type. Both types of loops are known to contribute to the radiation hardening and embrittlement of steels. In the literature many molecular dynamics works studying the interaction of dislocations with dislocation loops are available. Recently, based on such studies, a thermo-mechanical model to threat the dislocation - dislocation loop (DL) interaction within a discrete dislocation dynamics framework was developed for ½ < 111 > loops. In this work, we make a literature review of the dislocation - DL interaction in bcc iron. We also perform molecular dynamics simulations to derive the stress-energy function for < 100 > loops. As a result we deliver the function of the activation energy versus activation stress for < 100 > loops that can be applied in a discrete dislocation dynamics framework.

  15. Left Dislocation in Near-Native French

    ERIC Educational Resources Information Center

    Donaldson, Bryan

    2011-01-01

    The present study is concerned with the upper limits of SLA--specifically, mastery of the syntax-discourse interface in successful endstate learners of second-language (L2) French (near-native speakers). Left dislocation (LD) is a syntactic means of structuring spoken French discourse by marking topic. Its use requires speakers to coordinate…

  16. Computer simulation of screw dislocation in aluminum

    NASA Technical Reports Server (NTRS)

    Esterling, D. M.

    1976-01-01

    The atomic structure in a 110 screw dislocation core for aluminum is obtained by computer simulation. The lattice statics technique is employed since it entails no artificially imposed elastic boundary around the defect. The interatomic potential has no adjustable parameters and was derived from pseudopotential theory. The resulting atomic displacements were allowed to relax in all three dimensions.

  17. Dislocations - Multiple Languages: MedlinePlus

    MedlinePlus

    ... XYZ List of All Topics All Dislocations - Multiple Languages To use the sharing features on this page, please enable JavaScript. Arabic (العربية) French (français) Russian (Русский) Somali (af Soomaali) ...

  18. Traumatic proximal tibiofibular dislocation with neurovascular injury

    PubMed Central

    Veerappa, Lokesh A; Gopalakrishna, Chetan

    2012-01-01

    23 years old male presented with inferolateral dislocation of proximal tibiofibular joint associated with popliteal artery and common peroneal nerve injury. The extension of the injury to involve the interosseus membrane up to the distal tibiofibular joint. The association of popliteal artery injury is not reported before to the best of our knowledge. PMID:23162155

  19. [Open total dislocation of the talus].

    PubMed

    Grabski, R S; Sosiński, R

    1992-01-01

    A case of 35 years old patient with open, total, fixed dislocation of the talus reduced with heel traction is presented. The Sudeck syndrome subsided after one year. Weight bearing was not allowed for 7 months. An examination after 2.5 years revealed minor osteoarthritis, full range of movement in the foot but limited walking capability. PMID:7555299

  20. An unusual variant of perilunate fracture dislocations

    PubMed Central

    Morin, Matthew L.; Becker, Giles W.

    2016-01-01

    Abstract Trans-scaphoid, trans-radial styloid, trans-triquetral perilunate fracture dislocations are rare. We describe a 19-year-old male who suffered this injury after crashing his bicycle. He underwent open reduction internal fixation and percutaneous pinning. Scaphoid union was achieved at 8 weeks. Near complete range of painless motion was achieved by 4 months.