Occurrence of noise in alumina-on-alumina total hip arthroplasty. A survey on 284 consecutive hips.

BACKGROUND: Alumina-on-alumina bearings have been accepted as a valuable alternative for young and active patients. Alumina fractures, and socket loosening were the main complications reported. But, with the increasing number of prostheses implanted, noise occurrence appeared as a new concern. The primary aim of the present study was to quantify the prevalence of noticing noise in a population having received alumina-on-alumina total hip arthroplasty as well as its eventual impact on outcome. PATIENTS AND METHODS: Two hundred and eighty-four ceramic-on-ceramic hips were performed in 238 patients from January 2003 to December 2004. The average age was 52.4 ± 13.4 years (range, 13 to 74 years). All the hips received the same prosthesis (Ceraver-Osteal™) with alumina bearing components (Ceraver-Osteal™): 32 mm liners were used for cups of 50mm or larger and 28 mm liners for cups smaller than 48 mm; the minimal alumina thickness was 6mm. The acetabular component (Cerafit™) was hemispherical, coated with a hydroxyapatite layer and press-fit fixed. The stem (Cerafit™) was a straight tapered cementless stem, fully coated with a hydroxyapatite layer. Clearance between femoral head and liner was between 20 and 50 microns. A retrospective survey was conducted by an independent surgeon who did not participate to surgery in 2007. He conducted phone interviews of patients using a standard questionnaire. No suggestion was offered on how they could describe the noise and they felt free to use the word that they considered to be the most adapted. Satisfaction was evaluated. When the noise was present, X-rays were taken to assess if sign of bearings fracture was present. RESULTS: Four patients (six hips) died of unrelated causes during the follow-up period. Three patients (three hips) live outside France and could not be followed (1.3%). Nine patients (10 hips) could not be traced and were considered lost to follow-up (3.8%). Two hundred and twenty-two patients with 265 hips, therefore, were included (nine using bearing components in 28 mm diameter and 265 in 32 mm). Twenty-eight hips experienced noise generation (10.6%). It was defined as a snap for six patients, as a cracking sound by six, as rustling by six patients, as a squeaking by seven patients (2.6%), a tinkling by two patients, one patient was unable to define the sound she felt. No factor related to the patient influenced the occurrence of noise. Twelve patients were dissatisfied with the result of their hip prosthesis, five of them experienced noise (41.7%); 210 were satisfied or very satisfied, 23 of them experiencing noise (11%); this difference was significant (P=0.002). CONCLUSION: The origins of noise occurrence are unknown. Squeaking may be related to generation of stripe wear and absence of sufficient lubrication. Other types of noise can be due to microseparation, occult dislocation, impingement between the femoral neck and the acetabular rim. LEVEL OF EVIDENCE: Level IV. Retrospective study.

Cost analysis in total hip arthroplasty: experience of a teaching medical center located in Paris.

BACKGROUND: Since the beginning of 2008, the implementation of a 100% activity-based payment system, has made efficiency one of the prime concern for the French health-care providing institutions. We therefore assessed the real cost of a scheduled total hip replacement (THR) ina teaching hospital and compared findings with French national data (and with the Government Healthcare Insurance System allowance). HYPOTHESIS: The study should suggest possible means to optimize organization of management and/or clinicians' practice. MATERIAL AND METHODS: This is a retrospective full-cost economic study. Patients were included only if fulfilling the following criteria: admitted in 2006; classified in Diagnosis-Related Group (DRG) 08C23 V or 08C23W (respectively THR without and with associated comorbidity); treated in a single department; admitted from home; and having undergone a THR (coded as NEKA020 in the french CPT) that same year. Treatment-cost was established on the basis of data collected from two main sources: the Information Systems Medicalization Program (ISMP) data-base, and the finance department data, which were taken into account in line with the French National Costs Study (NCS) structure. RESULTS: The methodology employed here follows the 2006 National Costs Scale structure. Treatment costs (excluding the cost of implantable medical devices or IMDs) were estimated at 8,104.72 EUR for DRG 08C23W and 7,529.19 EUR for DRG 08C23 V. These figures were higher than the rates authorized in 2006 (excluding IMDs), which were 7,677.92 EUR for 08C23W and 6,358.97 EUR for 08C23 V (taking the 7% geographic coefficient into account) and than the 2005 NCS figures (excluding IMDs) of respectively 7,536.13 EUR and 6,083.59 EUR. DISCUSSION: Clinical units and departments need to be able to assess costs for the pathologies they treat, as health-care institutions have to balance their expenditure against their income, which largely comes from their hospital-care activity. The methodology put forward here, of cost comparison according to the NCS structure, enables the total cost to be known. Comparing results (expenditure line by expenditure line) against national data, selectively highlights the areas in which efficiency can be improved. The exactitude of the obtained results remains, however, limited by the rules currently in use at each individual hospital's accounting department. LEVEL OF EVIDENCE: Level IV, retrospective economic and decision analysis study.

Bone tissue response to titanium implant surfaces modified with carboxylate and sulfonate groups.

The present study assessed in vivo new bone formation around titanium alloy implants chemically grafted with macromolecules bearing ionic sulfonate and/or carboxylate groups. Unmodified and grafted Ti-6Al-4V exhibiting either 100% carboxylate, or 100% sulfonate, or both carboxylate and sulfonate groups in the percent of 50/50 and 80/20 were bilaterally implanted into rabbit femoral condyle. Neither toxicity nor inflammation were observed for all implants tested. After 4 weeks, peri-implant new bone formation varied as a function of the chemical composition of the titanium surfaces. The percent bone-implant contact (BIC) was the lowest (13.4 +/- 6.3%) for the implants modified with grafted carboxylate only. The value of BIC on the implants with 20% sulfonate (24.6 +/- 5.2%) was significantly (P < 0.05) lower than that observed on 100% sulfonate (38.2 +/- 13.2%) surfaces. After both 4 and 12 weeks post-implantation, the BIC value for implants with more than 50% sulfonate was similar to that obtained with the unmodified Ti-6Al-4V. The grafted titanium alloy exhibiting either 100% sulfonate or carboxylate and sulfonate (50% each) groups promoted bone formation. Such materials are of clinical interest because, they do not promote bacteria adhesion but, they support new bone formation, a condition which can lead to osseointegration of bone implants while preventing peri-implant infections.

Alumina-on-alumina hip arthroplasty in patients younger than 30 years old.

UNLABELLED: THA in patients younger than 30 years old presents challenges: the initial technical challenge relates to the initial disease that often causes deformities making reconstruction difficult, while the long-term challenge is wear and subsequent osteolysis and component loosening. Ceramic-on-ceramic prostheses may represent a valuable option to reduce wear. We retrospectively studied 101 patients (132 hips) with ceramic-on-ceramic prostheses implanted from 1977 to 2004. As a result of the long span of time, different implant designs and modes of fixation were used. The average age of the patients was 23.4+/-5 years (range, 13-30 years), and the main indication for THA was femoral head necrosis. The minimum followup was 1 year (mean, 6.9 years; range, 1-26.5 years). We documented 17 revisions (13%) for aseptic loosening. Twelve were for isolated acetabular loosening, two for isolated femoral loosening, and three for loosening of both components. Survivorship was 82.1% at 10 years and 72.4% at 15 years. Inferior survivorship was observed for THA performed after secondary arthritis related to slipped capital epiphysis or trauma. Limited osteolysis was observed in one hip. The main limiting factor in this series was the fixation of the acetabular component. However, improvements in the design and in the mode of fixation of this component should enhance long-term results. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Engineering of implantable cartilaginous structures from bone marrow-derived mesenchymal stem cells.

Fabrication of implantable cartilaginous structures that could be secured in the joint defect could provide an alternative therapeutic approach to prosthetic joint replacement. Herein we explored the possibility of using biodegradable hydrogels in combination with a polyglycolic acid (PGA) scaffold to provide an environment propitious to mesenchymal stem cells (MSCs) chondrogenic differentiation. We examined the influence of type I collagen gel and alginate combined with PGA meshes on the extracellular matrix composition of tissue-engineered transplants. MSCs were isolated from young rabbits, expanded in monolayers, suspended in each hydrogel, and loaded on PGA scaffolds. All constructs (n=48) were cultured in serum-free medium containing transforming growth factor beta-1, under dynamic conditions in specially designed bioreactors for 3-6 weeks. All cell-polymer constructs had a white, shiny aspect, and retained their initial size and shape over the culture period. Their thickness increased substantially over time, and no shrinkage was observed. All specimens developed a hyalin-like extracellular matrix containing glycosaminoglycans (GAGs) and type II collagen, but significant differences were observed among the three different groups. In PGA/MSCs and collagen-PGA/MSCs constructs, the cell growth phase and the chondrogenic differentiation phase of MSCs occurred during the first 3 weeks. In alginate-PGA/MSCs constructs, cells remained round in the hydrogel and cartilage extracellular matrix deposition was delayed. However, at 6 weeks, alginate-PGA/MSCs constructs exhibited higher contents of GAGs and lower contents of type I collagen. These results suggest that the implied time for the transplantation of in vitro engineered constructs depends, among other factors, on the nature of the scaffold envisioned. In this study, we demonstrated that the use of a composite hydrogel-PGA scaffold supported the in vitro growth of implantable cartilaginous structures cultured in a bioreactor system.

Engineering aspect of alumina on alumina hip prosthesis.

Alumina on the alumina sliding system in a total hip replacement is recognized as a breakthrough in orthopaedic surgery. Advantages and problems with this material are explained and discussed in the light of 36 years of clinical application. Laboratory data as well as clinical ones are summarized.

Embedding of bone samples in methylmethacrylate: a suitable method for tracking LacZ mesenchymal stem cells in skeletal tissues.

Considerable research has been focused on the use of bone marrow-derived mesenchymal stem cells (MSCs) for the repair of non-unions and bone defects. To date, the question of whether transplanted MSCs survive and engraft within newly formed tissue remains unresolved. The development of an easy and reliable method that would allow cell fate monitoring in transplant recipients is a pressing concern for the field of tissue engineering. To demonstrate the presence of transplanted cells in newly formed bone, we established a xenograft nude rat model allowing the detection of murine LacZ MSCs in vivo. MSCs were isolated from transgenic lacZ mice, seeded onto bioabsorbable collagen sponges, and transplanted to repair a calvarial defect in nude rats. As a preliminary step, the histological procedure was adapted to optimize the detection of LacZ cells in bone tissue embedded in methylmethacrylate (MMA). Four fixatives and four fixation times were evaluated. Among all the fixatives tested, 2% formaldehyde/0.2% glutaraldehyde at 4C for 4 days gave the best results for X-gal staining at pH 7.4 on both cell cultures and bone explants. All fixatives were effective for immunodetection of beta-gal. In the chimeric LacZ/nude rat animal model, MSCs were detected in vivo for up to 4 weeks after implantation and contributed to the repair and the neovascularization of the bone defect. LacZ is a suitable phenotypic marker to track MSCs in skeletal tissues embedded in MMA.

[Femoral reconstruction with impacted macroporous calcium phosphate ceramic in revision hip arthroplasty]. / Reconstruction fémorale par céramique de phosphate de calcium macroporeuse impactée au cours des reprises d'arthroplastie de hanche.

PURPOSE OF THE STUDY: Management of bone stock loss remains one of the most challenging problems for revision hip surgery. The aim of this retrospective study was to report the preliminary results of peri-prosthetic femoral defect reconstruction with impacted granules of calcium phosphate ceramic. MATERIAL AND METHODS: Fourteen hips in 13 patients (3 men and 10 women) were evaluated. Age at surgery ranged from 30 to 79 years (mean 66.1 years). All revised devices had been cemented. Femoral revision was indicated for loosening in eleven hips (including six septic cases), femoral osteolysis (one hip), persistent pain (one hip), and recurrent dislocation (one hip). On the preoperative radiological evaluation, bone defects were assessed as SOFCOT grade II in seven case, and grade III in fourteen. None was rated grade IV. Once the loose prosthesis had been removed, bone graft or ceramic granules (14 cases) were firmly impacted in the femoral canal. The stem was standard and always cemented using modern cementing technique. RESULTS: At a mean follow-up of 34 +/- 15 months (range 14-76 months), eleven of fourteen hips were rated good or very good according to the Postel-Merle-d'Aubigné score. One diaphyseal femoral fracture occurred and later united. Two hips required re-revision (one aseptic femoral loosening, one septic recurrence). Direct bonding between synthetic graft and bone was observed on standard radiographs in eleven cases. Stem subsidence occurred in two cases and was limited (mean 4.5 mm). DISCUSSION: Femoral bone reconstruction using impacted calcium phosphate ceramic in revision hip arthroplasty provided encouraging results in the short to mid term. Femoral stock restoration was achieved in the great majority. No adverse effect related to the use of a synthetic graft was noted. Further long-term evaluation is required before wider application.

[Idiopathic tumoral calcinosis: two cases and review of the literature]. / Calcinose tumorale idiopathique: A propos de deux cas et revue de la litterature.

Two black patients from Africa presented idiopathic tumoral calcinosis. This rare disease, defined by the presence of calcified deposits in peri-articular tissues remains poorly elucidated. Pathogenesis is still hypothetical. The diagnosis can be established with careful physical examination and appropriate complementary exams, allowing early complete surgical resection without biopsy. Pathology examination is required for formal differential diagnosis. The present tumors were particularly large, but did not produce signs of compression. In the first patient, the tumor developed after pregnancy in the zone of antibiotic injections. The second patient presented multiple bilateral symmetrical localizations with bone invasion. Histology confirmed the nature of the lesions and revealed bony metaplasie in the first patient, an element rarely described. Prognosis is excellent with early treatment. Recurrence is the rule in the event of incomplete resection. We discuss the appropriate diagnostic and therapeutic management.

Bone substitution in revision hip replacement.

The aim of this retrospective study was to report the preliminary results of femoral peri-prosthetic bone defect reconstruction with a synthetic bone substitute. Twenty-one revisions of the femoral component in 20 patients were evaluated. The mean age at operation was 65.7 years (range, 30 to 79 years). Preoperative femoral deficiencies were rated grade II in 7 cases and grade III in 14 cases according to the SOFCOT classification. None was rated grade IV. Femoral revision was indicated for loosening in 18 hips (including 8 septic cases), femoral osteolysis (1 hip), persistent pain (1 hip) and recurrent dislocation (1 hip). Once the loose prosthesis had been removed, calcium phosphate ceramic (CPC) granules (14 cases) or ceramic granules + cancellous allograft (5 cases) or autograft (2) were firmly impacted in the femoral canal. The stem was standard and always cemented using modern cementing technique. At a mean follow-up of 36 months (range, 14 to 76 months), 90% of the hips were rated good or very good according to the Merle d'Aubigné score. Two diaphyseal femoral fractures occurred and later united. Two hips required re-revision (aseptic loosening; septic recurrence). The absence of radiological osteolysis in 17 cases suggested direct bonding between ceramic granules and bone. Stem subsidence occurred in two cases and was limited (5 and 8 mm). Femoral bone reconstruction using impacted CPC or CPC in conjunction with bone graft in revision hip replacement commonly provided restoration of the bone stock in the short to mid-term. Further long-term studies will be necessary to support this conclusion.

Effect of microstructure on the mechanical properties of Haversian cortical bone.

The mechanical properties of cortical bone have been extensively studied at the macrostructural scale. However, knowledge of the macroscopic mechanical properties is not sufficient to predict local phenomena, such as damage or bone remodeling, both of which are dependent on local mechanical behavior. The objective of this study is to quantify the mechanical properties of cortical bone at several length scales, with emphasis on the microstructure of Haversian systems. Samples of mature bovine cortical bone, with a Haversian microstructure, were obtained from the posterior area of the mid-femoral diaphysis. A nanoindentation technique was used to measure the local Young's modulus. The distribution of the bone mineral content was obtained by backscattered electron imaging using a scanning electron microscope. A novel compression device employing microextensometry techniques was developed to quantify local strains. Digital image correlation was performed on the microstructure imaged by optical microscopy during compression tests. This study demonstrated that the local Young's modulus and strain were heterogeneous at the scale of an osteon. For both properties, the ratio between the maximum and minimum values was approximately two. The local Young's modulus and bone-mineral content were reasonably correlated (r2 = 0.75; P < 0.0001), but this was not the case for the distribution of local strains versus bone mineral content (r2 = 0.395; P < 0.0001). Hence, local strains cannot be described simply in terms of the bone mineral content, as the Haversian canal and osteonal microstructure have a major influence on these properties. In conclusion, the microstructure must be considered in evaluating the local strain and stress fields of cortical bone.

Surgical management of trapezius palsy.

BACKGROUND: Injury to the spinal accessory nerve in the posterior cervical triangle leads to paralysis of the trapezius muscle. The aim of this study was to determine the indications for nerve repair or reconstructive surgery according to the etiology, the duration of the preoperative delay, and specific patient characteristics. METHODS: Of twenty-seven patients with a trapezius palsy, twenty were treated with neurolysis or surgical repair (direct or with a graft) of the spinal accessory nerve and seven were treated with the Eden-Lange muscle transfer procedure. Lymph node biopsy was the main cause of the nerve injury. The nerve repairs were performed at an average of seven months after the injury, and the reconstructive procedures were done at an average of twenty-eight months. Nerve repair was performed for iatrogenic injuries of the spinal accessory nerve, within twenty months after the onset of symptoms, and in one patient with spontaneous palsy. Reconstructive surgery was performed for cases of trapezius palsy secondary to radical neck dissection, for spontaneous palsies, and after failure of nerve repair or neurolysis. The mean follow-up period was thirty-five months. The functional outcome was assessed clinically on the basis of active shoulder abduction, pain, strength of the trapezius on manual muscle-testing, and level of subjective patient satisfaction. RESULTS: The results were good or excellent in sixteen of the twenty patients treated with nerve repair and in four of the seven patients treated with the Eden-Lange procedure. Poor results were seen in older patients and in patients with a previous radical neck dissection. CONCLUSIONS: Good results can be expected from a repair of the spinal accessory nerve if it is performed within twenty months after the injury, as the nerve is basically a purely motor nerve and the distance from the injury to the motor end plates is short. Muscle transfer should be performed in patients with spontaneous trapezius palsy, when previous nerve surgery has failed, or when the time from the injury to treatment is over twenty months. Treatment is less likely to succeed when the patient is older than fifty years of age or the palsy was due to a radical neck dissection, penetrating injury, or spontaneous palsy.

De novo reconstruction of functional bone by tissue engineering in the metatarsal sheep model.

Large bone defects are still a challenge to orthopedic surgeons. In this study, a massive bone defect with a clinically relevant volume was efficiently reconstructed by transplanting an engineered bone in which mesenchymal stem cells (MSCs) expanded in autologous serum (AS) were combined with a porous scaffold. In the first step, we established that the way in which the MSCs are distributed over the scaffold affects the ultimate bone-forming ability of the transplant: constructs consisting of a natural coral scaffold and a pseudo-periosteal layer of MSCs surrounding the implant (coral-MSC3D) formed significantly more bone than constructs in which the MSCs were distributed throughout the implant (p = 0.01). However, bone healing occurred in only one sheep, owing to the high resorption rate of natural coral scaffold. To overcome this problem, constructs in which MSCs were combined with a porous coralline-based hydroxyapatite (CHA) scaffold having the same architecture as natural coral but a lower resorption rate were prepared. After their implantation, these constructs were found to have the same osteogenic potential as autologous bone grafts in terms of the amount of newly formed bone present at 4 months (p = 0.89) and to have been completely replaced by newly formed, structurally competent bone within 14 months. Nevertheless, although the rate of bone healing was strikingly improved when CHA-MSC3D constructs were used (five of seven animals healed) as compared with the coral-MSC3D construct (one of seven healed), it was still less satisfactory than that obtained with autografts (five of five healed).

[An uncommon form of delayed radio-induced brachial plexopathy]. / Une forme inhabituelle de plexopathie brachiale radio-induite tardive.

Radiation therapy of the neck or axillary areas for cancer may result in delayed brachial plexus palsy. Differential diagnosis between radiation and tumor brachial plexopathy is difficult. We report the case of a 38-year-old woman, treated by radiation therapy for osteosarcoma of the humeral head 22 years before, who exhibited a rapidly progressive incomplete hand palsy. EMG study revealed a conduction block at the level of the lateral cord. In this case, MRI could not distinguish between a delayed radiation injury and tumor infiltration. The diagnosis was clarified with an ultrasonographic examination. Neurolysis and epineurotomy of the median trunk in the brachial and axillary areas were performed. Histological examination confirmed radiation-induced nerve injury. The characteristics of this uncommon form are reviewed with regard to the previously reported descriptions.

A meta-analysis of patellar replacement in total knee arthroplasty.

From individual randomized studies it is unclear whether the patella should be replaced during total knee replacement. We did a meta-analysis to provide quantitative data to compare patellar resurfacing with nonresurfacing during total knee arthroplasty. Only randomized, controlled trials reported between January 1966 and August 2003 comparing patellar replacement with patella retention were included for a total of 12 studies. Two reviewers assessed trial quality and extracted data from papers. The outcomes identified were reoperations for patellar problems, anterior knee pain, knee scores, stair climbing, and patient satisfaction. The resurfaced patella performed better, and we found an increased relative risk (defined by the ratio of the risk of the event in the resurfaced group on the risk of the event in the nonresurfaced group) for reoperation, for significant anterior knee pain, and for significant pain during stair climbing when the patella was left unresurfaced. No differences were observed between the two groups for International Knee Society function score, Hospital for Special Surgery score, and for patient satisfaction. Despite these general findings, forming a definitive conclusion is difficult because many confounding factors, such as component design, surgeon experience, and technical aspects of the surgery, might influence the result in a patient.

[Distal femoral varus osteotomy for symptomatic genu valgum: long-term results and review of the literature]. / Ostéotomie fémorale distale de varisation pour genu valgum invalidant: résultats à long terme et revue de la littérature.

PURPOSE OF THE STUDY: We report our experience with eleven patients treated for disabling genu valgum from 1979 to 1994. MATERIAL AND METHODS: Genu valgum resulted from femoral deformation in all patients. Ten had a congenital condition and one a post-traumatic knee. IKS scores were used for the clinical evaluation. The lateral femorotibial joint space and the lateral femoral angle (LFA) were measured on plain films. Goniometry was used to measure the axis of the loaded lower limb. All patients underwent osteotomy of the distal femur for varisation and plate fixation. One patient required revision for a unicompartment lateral prosthesis subsequent to fracture of the homolateral lateral tibial plateau. Mean follow-up was 10.5 years (3.5-21.5). RESULTS: There were no cases of nonunion. Four patients had a good or excellent knee score. Eight patients had a good or excellent function score. Osteoarthritis worsened in two patients. The mean LFA increased from 72.5 degrees preoperatively to 83.5 degrees postoperatively and a last follow-up. Mean genu valgum was 13 degrees preoperatively and 2 degrees at last follow-up. All patients except one were satisfied or very satisfied. Insufficient correction appeared to be the main complaint. DISCUSSION: These results and results reported in the literature demonstrate that distal femoral osteotomy for disabling genu valgum is an effective treatment if the correction is complete and osteosynthesis effective, providing long lasting results when femoral deformation is involved and osteoarthritis limited.

Surgical management of trapezius palsy.

BACKGROUND: Injury to the spinal accessory nerve in the posterior cervical triangle leads to paralysis of the trapezius muscle. The aim of this study was to determine the indications for nerve repair or reconstructive surgery according to the etiology, the duration of the preoperative delay, and specific patient characteristics. METHODS: Of twenty-seven patients with a trapezius palsy, twenty were treated with neurolysis or surgical repair (direct or with a graft) of the spinal accessory nerve and seven were treated with the Eden-Lange muscle transfer procedure. Lymph node biopsy was the main cause of the nerve injury. The nerve repairs were performed at an average of seven months after the injury, and the reconstructive procedures were done at an average of twenty-eight months. Nerve repair was performed for iatrogenic injuries of the spinal accessory nerve, within twenty months after the onset of symptoms, and in one patient with spontaneous palsy. Reconstructive surgery was performed for cases of trapezius palsy secondary to radical neck dissection, for spontaneous palsies, and after failure of nerve repair or neurolysis. The mean follow-up period was thirty-five months. The functional outcome was assessed clinically on the basis of active shoulder abduction, pain, strength of the trapezius on manual muscle-testing, and level of subjective patient satisfaction. RESULTS: The results were good or excellent in sixteen of the twenty patients treated with nerve repair and in four of the seven patients treated with the Eden-Lange procedure. Poor results were seen in older patients and in patients with a previous radical neck dissection. CONCLUSIONS: Good results can be expected from a repair of the spinal accessory nerve if it is performed within twenty months after the injury, as the nerve is basically a purely motor nerve and the distance from the injury to the motor end plates is short. Muscle transfer should be performed in patients with spontaneous trapezius palsy, when previous nerve surgery has failed, or when the time from the injury to treatment is over twenty months. Treatment is less likely to succeed when the patient is older than fifty years of age or the palsy was due to a radical neck dissection, penetrating injury, or spontaneous palsy.

Hybrid alumina total hip arthroplasty using a press-fit metal-backed socket in patients younger than 55 years. A six- to 11-year evaluation.

Between 1990 and 1992, we implanted 71 hybrid alumina-on-alumina hip arthroplasties in 62 consecutive patients under the age of 55 years, with a mean age of 46 years at surgery. There were 56 primary and 15 secondary procedures. The prostheses involved a cemented titanium alloy stem, a 32 mm alumina head, and a press-fit metal-backed socket with an alumina insert. Three patients (four hips) died from unrelated causes. Four hips had revision surgery for either deep infection, unexplained persistent pain, fracture of the alumina head, or aseptic loosening of the socket. The nine-year survival rate was 93.7% with revision for any cause as the end-point and 98.4% with revision for aseptic loosening as the end-point. The outcome in the surviving patients (50 patients, 57 hips) with a minimum five-year follow-up (mean eight years) was excellent in 47 hips (82.5%), very good in eight (14%), good in one and fair in one. A thin, partial, lucent line, mainly in zone III was present in 38% of the sockets and one socket had a complete lucency less than 1 mm thick. One stem had isolated femoral osteolysis. There was no detectable component migration nor acetabular osteolysis. This hybrid arthroplasty gave satisfactory medium-term results in active patients. The press-fit metal-backed socket appeared to have reliable fixation in alumina-on-alumina hip arthroplasty. The excellent results using cemented fixation of the stem may be related to the low production of wear debris.