Frog leg lateral view is a reliable predictor of the prognosis in osteonecrosis of the femoral head.

The location and size of necrotic lesions are primary factors that predict the prognosis in osteonecrosis of the femoral head (ONFH). The Japanese Investigation Committee (JIC) classification system, based on the location of the necrotic lesion, has been widely accepted and applied around the world. However, there is no report about whether the location of the necrotic area in lateral view may affect the prognosis predicted initially by the JIC classification. The purpose of this study was to investigate whether the location of the necrotic area in the frog leg lateral (FL) view would affect the prediction of prognosis for patients with ONFH. We retrospectively studied 90 hips in 76 patients with ONFH (Ficat stage I to II) after a mean follow-up of 35.3 months. All patients received standard radiographs including an anteroposterior (AP) and a FL view of the affected hip. The percentage of the necrotic area (necrotic area/whole femoral head area) was measured and compared between AP and FL view. Hips with ONFH were categorized using the JIC classification and the FL view type system, and inter- and intraobserver reliability was compared between them. All patients underwent personalized hip physiotherapy, and the cumulative survival rate with subsequent collapse and/or requirement for further hip surgery as the endpoints was evaluated for the two classification systems. The percentage of the necrotic area was found to be significantly greater in the FL views (47.0 ± 1.5%) than that in the AP views (37.7 ± 1.7%, P < .01). Intraobserver reliability in the JIC classification (mean: 0.91, range: 0.85-0.98) was higher than that in the FL view type (mean: 0.77, range: 0.63-0.89; P < .01), as well as the interobserver reliability in the JIC classification (mean: 0.74, range: 0.38-0.87) was higher than that in the FL view type (mean: 0.58, range: 0.31-0.76; P < .01). Comparisons of survival curves showed that type III in FL view type had the worst prognosis than other two divisions, following the type II. The type I was likely to gain optimal outcomes. These findings provide evidence that the location to which necrosis extended in the FL view is a reliable indicator in predicting the prognosis of ONFH.

Clinical efficiency of bone marrow mesenchymal stem cell implantation for osteonecrosis of the femoral head: a matched pair control study with simple core decompression.

BACKGROUND: To date, several trials have reported the use of mesenchymal stem cell (MSC) implantation for osteonecrosis of the femoral head (ONFH). However, the clinical outcomes have not been conclusive. This study compared the clinical and radiological results of bone marrow mesenchymal stem cell (BMMSC) implantation with traditional simple core decompression (CD) using a matched pair case-control design. METHODS: We retrospectively reviewed 100 patients with ONFH (106 hips) who had been treated by CD alone (50 patients, 53 hips) and CD + BMMSC implantation (50 patients, 53 hips) between February 2004 and October 2014. We assessed the total hip replacement arthroplasty (THA) conversion rate and ARCO (Association Research Circulation Osseous) stage progression. Survivor rate analysis was performed using the Kaplan-Meier method, and an additional THA was defined as the primary endpoints. RESULTS: The mean follow-up period was 4.28 years. There was a difference in the THA conversion rate between the CD (49%) and CD + BMMSC groups (28.3%) (p = 0.028). ARCO stage progression was noted in 20 of 53 hips (37.7%) in the CD group and 19 of 53 hips (35.8%) in the CD + BMMSC group. Among collapsed cases (ARCO stages III and IV), there was no difference in clinical failure rate between the two groups. Conversely, in the pre-collapse cases (ARCO stages I and II), only 6 of 30 hips (20%) progressed to clinical failure in the CD + BMMSC group, whereas 15 of 30 hips (50%) progressed to clinical failure in the CD group (p = 0.014). Kaplan-Meier survival analysis showed a significant difference in the time to failure between the two groups up to 10-year follow-up (log-rank test p = 0.031). There was no significant difference in terms of age (p = 0.87) and gender (p = 0.51) when comparing THA conversion rates between groups. No complication was noted. CONCLUSIONS: These results suggest that implantation of MSCs into the femoral head at an early stage of ONFH lowers the THA conversion rate. However, ARCO stage progression is not affected by this treatment. TRIAL REGISTRATION: Retrospectively registered.

Regenerative therapies increase survivorship of avascular necrosis of the femoral head: a systematic review and meta-analysis.

PURPOSE: The aim of this study was to document the available evidence on the use of regenerative techniques for the treatment of femoral head osteonecrosis (or avascular necrosis of femoral head, AVN) and to understand their benefit compared to core decompression (CD) alone in avoiding failure and the need for total hip replacement (THR). METHODS: The search was conducted on three medical electronic databases according to PRISMA guidelines. The studies reporting number and timing of failures were included in a meta-analysis calculating cumulative survivorship with a Kaplan-Mayer curve. Moreover, the results on failures in treatment groups reported in RCT were compared with those documented in control groups, in order to understand the benefit of biological therapies compared to CD for the treatment of AVN. RESULTS: Forty-eight studies were included in this systematic review, reporting results of different types of regenerative techniques: mesenchymal stem cell implantation in the osteonecrotic area, intra-arterial infiltration with mesenchymal stem cells, implantation of bioactive molecules, or platelet-rich plasma. Overall, reported results were good, with a cumulative survivorship of 80% after ten year follow-up, and better results when regenerative treatments were combined to CD compared to CD alone (89.9% vs 70.6%, p < 0.0001). CONCLUSION: Regenerative therapies offer good clinical results for the treatment of AVN. The combination of CD with regenerative techniques provides a significant improvement in terms of survivorship over time compared with CD alone. Further studies are needed to identify the best procedure and the most suitable patients to benefit from regenerative treatments for AVN.

Effects of electrical stimulation in the treatment of osteonecrosis of the femoral head.

INTRODUCTION: The aim of this study was to examine whether the use of an internal electrostimulator could improve the results obtained with core decompression alone in the treatment of osteonecrosis of the femoral head. METHODS: We performed a retrospective study of 41 patients (55 hips) treated for osteonecrosis of the femoral head between 2005 and 2014. Mean follow-up time was 56 (12-108) months. We recorded 3 parameters: time to recurrence of pain, time to conversion to arthroplasty and time to radiographic failure. Survival was estimated using the Kaplan-Meier method. The equality of the survival distributions was determined by the Log rank test. RESULTS: Implanted electrostimulator was a factor that increased the survival of hips in a pre-op Steinberg stage of II or below, while it remained unchanged if the stage was III or higher. CONCLUSIONS: The addition of an internal electrostimulator provides increased survival compared to core decompression alone at stages below III.

Comparison of Surgical Parameters and Results between Curved Varus Osteotomy and Rotational Osteotomy for Osteonecrosis of the Femoral Head.

BACKGROUND: Various osteotomies have been introduced to treat osteonecrosis of the femoral head. The purpose of this study was to compare surgical parameters, postoperative limb length discrepancy, and minimum 5-year clinical and radiological results between transtrochanteric curved varus osteotomy (TCVO) and transtrochanteric rotational osteotomy (TRO) for osteonecrosis of the femoral head. METHODS: From 2004 to 2009, 103 consecutive TROs (97 patients) followed by 72 consecutive TCVOs (64 patients) were performed for the treatment of osteonecrosis of the femoral head. Of these, 85 patients (91 hips) in the TRO group and 58 patients (65 hips) in the TCVO group completed minimum 5-year clinical and radiological follow-up. The Kaplan-Meier product-limit method was used to estimate survival. RESULTS: The TCVO group had shorter operation time (p < 0.05) and less estimated blood loss (p = 0.026). Postoperative collapse developed in 26 hips (28.6%) in the TRO group and 7 hips (10.8%) in the TCVO group (p = 0.007). Osteophyte formation was observed in 34 hips (37.4%) in the TRO group and 13 hips (20%) in the TCVO group (p = 0.020). Fifteen hips (16.5%) in the TRO group and 7 hips (10.8%) in the TCVO group underwent conversion total hip arthroplasty (THA). The survival rate at 9 years with radiographic collapse as the endpoint was 68.7% (95% confidence interval [CI], 58.1% to 79.3%) in the TRO group, and 84.7% (95% CI, 71.5% to 97.9%) in the TCVO group. With conversion to THA as the endpoint, the survival rate was 82.2% (95% CI, 73.1% to 91.3%) in the TRO group and 89.2% (95% CI, 81.7% to 96.7%) in the TCVO group. CONCLUSIONS: The comparison indicates that TCVO was better than TRO in terms of surgical parameters including operation time and estimated blood loss while the 9-year survival rates were similar.

Porous Tantalum Implant in Treating Osteonecrosis of the Femoral Head: Still a Viable Option?

The purpose of this study is to evaluate the survivorship and risk factors for radiographic progression and conversion to total hip arthroplasty (THA) after porous tantalum implant surgery in the treatment of osteonecrosis of the femoral head (ONFH). The study comprised 90 ONFH patients (104 consecutive hips) who were treated with a porous tantalum implant combined with bone grafting between June 2008 and December 2013. The patients were 19-61 years of age (mean age, 38 years). The mean follow-up was 42 months. The outcome measures included Harris hip score (HHS), radiographic outcome measures, and survivorship analysis with conversion to THA as the endpoint. The mean postoperative HHS was significantly lower than the mean preoperative HHS (P < 0.001). The Cox proportional hazards model showed that age and Association Research Circulation Osseous (ARCO) stage were independent risk factors for conversion to THA, while age, China-Japan Friendship Hospital (CJFH) type, and ARCO stage were independent risk factors for radiological progression. Ultimately, only 52.9% hips survived. Porous tantalum implant surgery combined with bone grafting is not a viable option for treating ONFH, especially in patients >35 years of age with preoperative ARCO stage III and CJFH type L3.

Tantalum rod implantation for femoral head osteonecrosis: survivorship analysis and determination of prognostic factors for total hip arthroplasty.

PURPOSE: The purpose of this study was to evaluate the moderate survival data of porous tantalum rod implants for the treatment of osteonecrosis of the femoral head (ONFH). Additionally, some independent prognostic factors for conversion to total hip arthroplasty (THA) were identified. METHODS: The porous tantalum rod population was obtained from a prospective, consecutive group of patients treated for Steinberg stage I and II osteonecrosis from April 2009 through July 2011. The historical core decompression and impaction of bone filling particle subjects underwent surgery from April 2007 through March 2009. Surgical data including time of surgery, blood loss, and cell transfusions were recorded. Post-operative values were measured for hospitalization length as well as days requiring a patient-controlled analgesia (PCA) pump. Primary outcomes were Harris hip score and survivorship analysis. Demographics and baseline characteristics included age, sex, etiology, bilateral disease, associated chronic systemic disease, Steinberg stage, Harris hip score, accompanied with bone marrow edema of femoral head, and osteonecrotic lesion size. RESULTS: Demographic/baseline characteristics were similar between two groups. At the post-operative follow-up of 62 months, Harris hip scores were significantly increased (P < 0.0001) when compared to that before surgery in both groups. The magnitude of increase in the tantalum rod implant group was significantly greater than that in the control group (P = 0.0426). With an average follow-up of 48 months (range, 38-62 months), the tantalum rod group had an 84.6 % survival rate. With an average follow-up of 72 months (range, 67-85 months), the control group had a 63.3 % survival rate. A comparison of Kaplan-Meier curves showed significantly higher cumulative survival rates (P = 0.048) for hips with implantation of the porous tantalum rod (74.1 % at 62 months) than for those with impaction composite bone material (49.9 % at 62 months). The Cox proportional-hazard model revealed that implantation of tantalum rod (P = 0.012), bone marrow edema (P = 0.003), corticosteroids intake (P = 0.007), and age less than 50 years (P = 0.014) were the independent prognostic factors related to conversion into THA. CONCLUSIONS: Compared with the traditional impaction composite bone material technique, implantation of tantalum rod in the treatment of Steinberg stages I and II ONFH can obtain better clinical results and higher cumulative survival rates. For patients without the use of corticosteroids, and especially for hips without bone marrow oedema, the clinical results from our study show highly encouraging survival rates and a delay in or prevention of conversion into THA.

Recombinant human bone morphogenetic protein-2 in debridement and impacted bone graft for the treatment of femoral head osteonecrosis.

The purpose of this study was to compare the clinical outcomes of impacted bone graft with or without recombinant human bone morphogenetic protein-2 (rhBMP-2) for osteonecrosis of the femoral head (ONFH). We examined the effect of bone-grafting through a window at the femoral head-neck junction, known as the "light bulb" approach, for the treatment of ONFH with a combination of artificial bone (Novobone) mixed with or without rhBMP-2. A total of 42 patients (72 hips) were followed-up from 5 to 7.67 years (average of 6.1 years). The patients with and without BMP were the first group (IBG+rhBMP-2) and the second group (IBG), respectively. The clinical effectiveness was evaluated by Harris hip score (HHS). The radiographic follow-up was evaluated by pre-and postoperative X-ray and CT scan. Excellent, good, and fair functions were obtained in 36, 12, and 7 hips, respectively. The survival rate was 81.8% and 71.8% in the first and second group, respectively. However, the survival rate was 90.3% in ARCO stage IIb, c, and only 34.6% in ARCO stage IIIa (P<0.05). It was concluded that good and excellent mid-term follow-up could be achieved in selected patients with ONFH treated with impacted bone graft operation. The rhBMP-2 might improve the clinical efficacy and quality of bone repair.

[Short-term curative effects of Tantalum rod treatment in early avascular necrosis].

OBJECTIVE: To explore the recent clinical curative effect of Tantalum rod in treating the early avascular necrosis. METHODS: From January 2008 to November 2008, the 25 patients (39 hips) with early avascular necrosis accepted tantalum rod placement and included 9 males (11 hips) and 16 females (28 hips) with an average age of 37 years old ranging from 18 to 74 years old. Four patients (6 hips) caused by Alcoholic, 6 patients (8 hips) by hormone, 2 cases (2 hips) by traumatic, 13 cases (23 hips) by idiopathic. Steinberg preoperative stage involved 7 hips in period I, 24 hips in period II, 8 hips in period III. Curative effect analysis included preoperative and postoperative Harris score, radiographic changes and hip replacement for follow-up to accept the end of the femoral head survival rate. RESULTS: All patients were followed up for 6 to 47 months (averaged 37.4 months). All 12 hips imaging appeard progress,including tantalum rod exit in 1 hip, hip hemiarthroplasty collapse in 3 hips, the area increased to avascular necrosis in 8 hips. Six hips accepted total hip replacement, including imaging progress in 5 hips (41.7%, 5/12), no imaging progress in 1 hip (3.7%,1/27). All hips' Kaplan-Meier survival curves showed 6-month survival rate was (97.4 +/- 2.5)% after tantalum stick insertion, 1-year survival rate was (94.7 +/- 3.6), and 2-year survival rate was (88.6 +/- 5.4)%, 3-year survival rate was (72.5 +/- 11.2). CONCLUSION: It is effective for treatment of avascular necrosis of femoral head in Steinberg I and II by Tantalum rod, and it can effectively relieve femoral head replacement time.

Combined tantalum implant with bone grafting for the treatment of osteonecrosis of the femoral head.

BACKGROUND: The purpose of this study was to evaluate the short-term clinical outcome of using a tantalum implant in combination with bone grafting for the treatment of osteonecrosis of the femoral head. METHODS: Sixty-nine patients with 94 osteonecrotic hips were treated with this method from March 2006 to March 2011. All the patients were treated with tantalum rod implantation in combination with bone grafting, and were followed for an average 35.4 months. Harris hip score and the survival rate were analyzed according to stage, etiology, and osteonecrosis part. RESULTS: Patients with stage I and stage II diseases had significant greater Harris hip score improvement than patients having stage III disease (p < .05). The survival rate was also significantly higher in patients with stage I and stage II diseases than in patients having stage III disease (p < .05). Patients with type A and type B necrotic lesions had better recovery than patients with type C1 and type C2 having lateral column lesions (p < .05). No significant differences were detected in the clinical outcome among patients with different etiologies. CONCLUSION: Combined tantalum implant with bone grafting provided good short-term clinical outcomes for early stage I and stage II patients with type A and type B necrotic lesions. However, this treatment modality was not so effective for patients with stage III or type C1 and type C2 necrotic lesions.

Regulation of VEGF expression by HIF-1α in the femoral head cartilage following ischemia osteonecrosis.

Juvenile femoral head osteonecrosis is due to disruption of blood supply which results in ischemic injury. Angiogenesis is an essential component for the healing of damaged head. Hypoxia-inducible factor-1α (HIF-1α) is a master regulator of cellular response to hypoxia. Our histological studies showed increased vessel formation in cartilage in the ischemic group compared to the control group in a pig model of femoral head osteonecrosis. Microarray and RT-PCR indicated that VEGF expression was upregulated along with HIF-1α in the ischemic side. Immunohistochemistry assay demonstrated that HIF-1α and VEGF were upregulated in chondrocytes in ischemic femoral heads. Both HIF-1α and VEGF expression increased in primary chondrocytes under hypoxia station. Interestingly, an HIF-1α activator DFO further enhanced VEGF expression. Moreover, transfection of siRNA directed against HIF-1α led to inhibition of VEGF expression. Taken together, our data indicated that upregulation of VEGF during hypoxia in chondrocyte is mediated partially through HIF-1α.

Clinical and morphological investigations on the prevalence of lameness associated with femoral head necrosis in broilers.

1. The aim was to determine the prevalence of femoral head necrosis (FHN) as a cause of lameness in broilers, and to increase knowledge of its morphological features and aetiology. The studies were carried out in two farms (A and B) in Bulgaria, on 650,000 chickens from 38 flocks. 2. Lameness in broilers varied from 3-4% up to 15% for both farms. In affected flocks, mortality due to lameness ranged between 5-6% and 10%. 3. We documented lesions in 520 broilers with signs of lameness. Samples for histopathological examination were obtained from the femur--135 from farm A and 120 from farm B. The samples originated from different batches of broilers, during different seasons of the year, and from chickens originating from parent flocks of different ages. 4. E. coli was isolated in more than 90% of the bacteriologically tested samples with FHN associated with osteomyelitis. Our large-scale field tests showed that FHN was the commonest cause of lameness in broilers.

THA using an anatomic stem in patients with femoral head osteonecrosis.

Treating young patients with femoral head osteonecrosis (ON) remains challenging. Anatomic stems were introduced in the 1980s and 1990s to improve the proximal canal fit in an attempt to enhance long-term implant survival, an important aspect of treating young patients. We began using one design in 1993 and asked three questions to confirm whether the design criteria improved outcomes in patients with ON: (1) What is the long term survivorship of these implants?; (2) What is the amount and rate of wear?; and (3) What is the incidence of osteolysis? We retrospectively reviewed 56 patients (69 hips) who underwent THA for femoral head ON with a cementless anatomic stem proximally coated with hydroxyapatite. Four patients (four hips) were lost to followup and 16 patients (19 hips) died. In the remaining 36 patients (46 hips) the minimum followup was 10 years (mean, 11.2 years; range, 10-13 years). The mean age at operation was 48.6 years. The average Harris hip score at last followup was 87 points. Worst-case survivorship was 58.1% at 13 years and best-case was 93.3%. The average linear wear of the polyethylene liner was 2.02 mm and the average annual wear was 0.18 mm per year. Thirty-seven hips (80%) had femoral osteolysis and 14 (30%) had acetabular osteolysis. One patient who had extensive femoral osteolysis and stem loosening was revised at 11.2 years postoperatively. The high rates of polyethylene wear and osteolysis are of concern.

Transtrochanteric posterior rotational osteotomy for osteonecrosis.

When osteonecrosis is located in the mid- to posterior region, we generally perform a transtrochanteric posterior rotational osteotomy. We retrospectively reviewed the clinical and radiographic results in 47 consecutive patients (51 hips) in whom we performed posterior rotational osteotomies. The average age was 37 years at the time of surgery. There were 30 male and 17 female patients. Thirty-six hips were ARCO Stage III, and 15 were Stage IV. Conversion to THA was defined as the failure end point. Three patients died and one was lost to followup. We were therefore able to follow 43 patients (46 of the 51 hips, or 90%) a minimum of 1.2 years (average, 12 years; range, 1.2-21 years). We used the Harris hip score for preoperative and most recent followup. The average preoperative Harris hip score of 52 points improved to an average of 84 at the latest followup. Radiographically, the osteonecrosis in 30 hips (65%) had no progressive collapse, and 13 (28%) showed osteoarthritic changes, but no patients underwent THA. A posterior rotational osteotomy appears useful for patients with extensive necrosis and advanced collapse.

Long-term survivorship analysis of cemented total hip replacement (THR) after avascular necrosis of the femoral head in renal transplant recipients.

BACKGROUND: We studied the long-term survival and the rate of revision of 93 consecutive total hip replacements (THRs) performed for avascular necrosis of the femoral head after renal transplantation from 1971 to 1988. Seventy-four were primary procedures while 19 hips had undergone previous surgery procedures on the same hip in the form of other conservative options. METHODS: The patients of mean age of 38 years were analysed by the Kaplan-Meier method with revision for any reason as the end-point. The follow-up period averaged 216 months (range 1-332). RESULTS: Thirteen hips were revised while 26 patients (36 hips) died during the follow-up period. The cumulative survival of the implant was 98.8% at 10 years and 63.8% at 20 years. CONCLUSIONS: Cemented THR performed after renal transplantation is satisfactory and, at least for the first 10 post-operative years, the results are equivalent to those obtained in the general population with primary osteoarthritis.

Primary exeter total hip arthroplasty in patients with small femurs: a minimal of 10 years follow-up.

One hundred and twelve hips in 101 Chinese patients received primary cemented Exeter total hip arthroplasty (Howmedica, Hong Kong). The implant had a collarless, double-tapered and polished stem. Seventy-five hips in 67 patients were available for assessment. The average age at operation was 63.7 years. The commonest diagnosis was avascular necrosis. The average follow-up was 12.8 years (range, 10 to 16.5 years). The Harris score improved from a preoperative average of 39.8 to 82.3 at the last follow-up. Stem subsidence within the cement mantle occurred in 9.3% of the cases and none of these stems had other evidence of loosening. Eight hips (six stems and two cups) in seven patients were revised because of loosening at five to 14 years postoperatively. The survival rate was 93.3% and 86% at 10 and 15 years respectively. Oversized stems and incomplete cement mantle might account for the loosening. Stems of a smaller size have been made available to this population and hopefully this will improve the results further.

Long-term results of alumina-on-alumina hip arthroplasty for osteonecrosis.

Alumina-on-alumina bearings in THR may, in theory, provide an effective answer to osteolysis in young patients with ON of the femoral head. The purpose of this retrospective study was to report the long-term results of a series of 52 consecutive alumina THAs (41 patients) done for ON. The mean age of the patients at surgery was 41 years (range, 22-79 years). Cemented femoral stems with a 32-mm alumina head were used. Plain alumina cups were used and were either cemented (39 hips) or press-fit (13 hips). No patients were lost to followup. Sixteen hips have been revised. Aseptic loosening of the socket was the main cause of failure. At an average 16-year followup (range, 11-23.65 years), 26 hips were rated excellent and one hip was rated good. No osteolysis was observed and wear was undetectable. If revision for aseptic loosening was the end point, the rate of survival was 88.5% at 10 years for the socket and 100% at 10 years for the stem. With the alumina-on-alumina hip replacement done for ON, absence of osteolysis can be expected for as many as 24 years after the operation. New methods of socket fixation now are being explored.

Mid-term prognosis of non-traumatic osteonecrosis of the femoral head.

We followed, prospectively, 77 patients (90 hips) with early-stage, non-traumatic osteonecrosis of the femoral head for a mean period of nine years. At the time of final review, 56 (62%) were symptomatic. Using the Cox model, the initial radiological stage, the progression of staging, the reduction in size of the lesions and the percentage of necrotic volume on MRI were identified as risk factors. Using the Harris score of < 70 or surgery as the endpoint, the cumulative rates of survival were 60.0% at one year, 43.3% at two years, 38.9% at five years and 37.2% at ten years. Survival curves demonstrated that clinical deterioration could occur 90 months after the initial diagnosis, suggesting that asymptomatic patients should be followed carefully for several years. Radiological time-dependent reduction in size without progressive collapse may represent repair even when the collapse is minimal.

[Total hip arthroplasty and femoral head osteonecrosis in renal transplant recipients]. / Prothèse totale de hanche pour ostéonécrose de la tête fémorale chez le transplanté rénal.

PURPOSE OF THE STUDY: Osteonecrosis of the femoral head is reported in a very variable proportion of renal transplant recipients. When these patients require total hip arthroplasty (THA), immunosuppression and poor bone quality increase the risk of aseptic loosening and infection. In the literature, functional outcome has been satisfactory although rates of early and late complications have varied greatly. The purpose of our work was to determine the long-term outcome in a series of renal graft recipients who underwent THA for osteonecrosis of the femoral head. MATERIAL AND METHODS: Forty-eight THA were implanted for aseptic osteonecrosis of the femoral head (Ficat grade III and IV) in 32 renal transplant recipients between 1974 and 1995 (21 men and 11 women). Mean age was 30 years at transplantation and 39 years at THA surgery. Thirty patients had been on hemodialysis for a mean 1 year prior to transplantation. Joint disease concerned 2 or more joints in 23 of the 32 patients. Fifteen hips had a surgical history: 8 drillings and 3 head arthroplasties. The THA was implanted under general anesthesia via the posterolateral approach. All implants were fixed with a gentamycin cement. A cephalosporin was used for the antibiotic prophylaxis in 20 cases and a cephalosporin/vancomycin combination in 24. Functional outcome was assessed with the Postel-Merle-d'Aubigné (PMA) score. Functional gain was [(PMAreview-PMApreop)/PMApreop]. General or local complications were recorded at last follow-up. The complete or incomplete nature of lucent lines seen on the last follow-up x-rays and their evolution were also recorded. Reasons for second procedures were noted. RESULTS: Early complications were: phlebitis (n=1), hematoma (n=7), dislocation (n=1), deep infection (n=2). At last follow-up (mean=5 years 7 months), four patients (6 THA) had died and six (7 THA) were lost to follow-up. Preoperatively, function was scored fair or poor in 91% of the patients. At last follow-up function was scored good, very good, or excellent in 75%. Mean functional gain was 38%. A second operation was necessary for seven THA due to aseptic loosening (mean delay 9 years 10 months), for five others for septic loosening (mean delay 6 years 8 months), and finally for two for instability (one early and the other after more than 2 years). In all, 29% of the THA were reoperated. Two deaths were related to late THA infection. Active lucent lines were observed in 11% of the THA (excepting patients reperated for loosening). DISCUSSION: The functional gain provided by THA in renal transplant recipients with aseptic osteonecrosis of the femoral head is clearly established. Implant survival remains a problem. The rate of early local complications was high in our series, mainly related to hematoma formation and infection. The infections observed were particularly severe requiring early comprehensive management at onset of clinical signs. For patients with suspected deep infection, we propose an aspiration biopsy of the joint to obtain a bacteriological sample. CONCLUSION: THA enables good functional outcome for renal transplant recipients suffering from osteonecrosis of the femoral head, but at the cost of a high risk of early and long-term complications not always reported in the literature.