Frühlockerungen eines zementierten Hüftendoprothesenstiels aus Titan

Up to now there are no facts concerning the loosening rate of the cemented titanium stem (Trios). The central guiding canula and the longitudinal drilled stem shall ensure a symmetric cement mantle. In order to estimate the risk of aseptic loosening all Trios prostheses implanted in our clinic (n = 67; operations 1/95-11/96; max. follow-up: 3.1 years) were examined in a retrospective study and compared with a conventional femoral component (n = 141; Müller special; CoCr; operations 1977-1982). We used survivorship analysis to assess the results (Kaplan-Meier method; end point: revision). Compared to the conventional femoral stem the survival rate of the Trios prostheses was significantly worse (p = 0.0001). The probability of no revision after 3 years was 72% (conventional femoral component: 96%). Preoperative x-rays showed radiolucent lines surrounding the cement mantle. These findings as well as the loosening at the cement metal interface were confirmed intraoperatively. The explanted stems showed corresponding signs of abrasion on the surface. Our results prove that the application of cemented titanium stems might be problematic. With regard to the Trios prosthesis we recommend close routine check-ups to keep the chance of an early revision.     

Fifteen-year Results of Precoated Femoral Stem in Primary Hybrid Total Hip Arthroplasty

Background

There has been controversy whether methylmethacrylate precoating of the cemented femoral stem is a solution for aseptic loosening or rather contributes to increased failure rates in cemented total hip arthroplasties.

Methods

On a retrospective basis, we analyzed 76 primary hybrid total hip arthroplasties from 63 patients with precoated, cemented femoral stems between October 1990 and December 1995. The mean age of the patients was 46.8 years (range, 22 to 77 years) with a minimum follow-up of 14 years (mean, 15.5 years; range, 14 to 19.5 years). Third generation cementing techniques were employed in all cases.

Results

Twenty-four out of 76 cases (31.6%) showed aseptic loosening of the femoral stems, of which 23 stems were revised at an average revision time of 8 years (range, 3 to 14.8 years). The main mode of loosening was cement-stem interface failure in 22 hips (91.7%). Twenty-one out of 24 failed hips (87.5%) demonstrated C2 cementing grades (p < 0.001). Kaplan-Meier survivorship analysis using radiographic aseptic loosening of the femoral stem as the endpoint for failure showed survival rates of 76.5% at 10 years (95% confidence interval [CI], 71.4 to 81.6) and 63.2% at 19 years (95% CI, 57.3 to 69.1).

Conclusions

An early failure of the precoated femoral stem in this study was mainly due to an insufficient cementing technique. Achievement of good cement mantle may improve the survival rates.     

Results with the M. E. Müller cemented, straight-stem total hip prosthesis: a 10-year historical cohort study in 180 women

In 1986, 242 M. E. Muller (MEM) cemented, straight-stem total hip arthroplasty prostheses were implanted in 229 patients; 15 hips (13 patients) were lost to follow-up. Of the remaining 227 implants, 180 were placed in women, and 47 were placed in men (each with mean age, 71 +/- 7.7 years). After 10 years, 66 patients had died, and 152 implants were still in situ. As a result of aseptic loosening, 9 hips were revised (5 femoral and 4 acetabular components); two of these patients had a Girdlestone as a result of postoperative infection. Because 50% of the men died during follow-up, further analysis was performed with the 180 implants in women. The incidence of revision for aseptic loosening was 5.9 per 1,000 implants. The cumulative survival rate after 10 years was 94%. Survival was not influenced significantly by age, indication for operation, or having a contralateral hip prosthesis. The 10-year follow-up results for the MEM straight-stem total hip prosthesis in our hospital are satisfactory despite the probability that the cement mantle produced with this stem is not uniform in thickness.     

Ten-year follow-up of primary straight-stem prosthesis (MEM) made of titanium or cobalt chromium alloy

Introduction An increased revision rate of cemented titanium stems compared with cobalt chromium stems has been described after a short follow-up. In this paper, the minimum 10-year outcome after the implantation of titanium (Ti) and cobalt chromium ME (CoCr) Mueller straight-stem prostheses is analyzed in order to estimate the prognosis of the patients who were not revised.Materials and methods A total of 272 (Ti) straight stems were implanted between 1987 and 1990, and 161 (CoCr) straight stems were implanted from 1984 to 1987. Clinical and radiological checks were carried out prospectively after 1, 2, 5, and 10 years.Results The survival rate concerning aseptic loosening of the stem after 5 years was 92.8% (Ti)/100% (CoCr) and after 10 years 80.9%/98.2%. Thirty-six (Ti)/2 (CoCr) patients required revision of the stem due to aseptic loosening. The revision rate per year of the Ti stems increased until 7 years postoperatively and decreased thereafter. At the 10-year follow-up, 107 Ti and 84 CoCr implants were checked, and the subjective and clinical parameters did not differ between the two groups.Conclusion Except for an increased subsidence rate of the stems in the Ti (31%) versus the CoCr group (16%), there was no statistically significant difference in the clinical and radiological outcomes.     

Staged bilateral total hip arthroplasty using rough and smooth surface femoral stems with similar design: 10-year survivorship of 48 cases

BACKGROUND: Various studies have reported good long-term results using femoral stems with either smooth or rough surfaces. In this retrospective cross-sectional survivorship study, we reviewed the 10-year results of 51 bilateral staged cemented total hip arthroplasties using the Harvard or the Charnley femoral stems-which have almost similar geometry but a different surface finish. METHODS: 51 patients were reviewed at median interval of 10 (Harvard group) and 11 years (Charnley group) after the primary operation. We evaluated cement mantle thickness, alignment of the components, presence of radiolucent lines, and aseptic loosening. Kaplan-Meier analysis was performed to calculate the survival rate using various endpoints. RESULTS: 8 hips in the Harvard group were revised for aseptic loosening of the femoral component at a median interval of 6.3 years after the primary procedure. 3 hips in the Charnley group were revised for aseptic loosening of the femoral and acetabular components between 10 and 11 years after the primary procedure. The 10-year survival rate for the femoral component using revision surgery for aseptic loosening as an endpoint was 80% (95% CI: 31-42) and 95% (95% CI: 44-47) in the Harvard and the Charnley group, respectively. Cox regression analysis did not reveal any statistically significant effect of various radiographical parameters on the survival rate (p < 0.05). INTERPRETATION: Our results demonstrate that in the group of patients studied, the femoral stem component with the matt surface finish had less satisfactory 10-year survival than the femoral stem of similar design which had a smooth surface finish.     

Clinical outcome in total hip arthroplasty using a cemented titanium femoral prosthesis

Between 1988 and 1993, 118 total hip arthroplasties were carried out using cemented titanium alloy stems with modular cobalt-chrome heads. At a mean follow-up of 66.2 months, the overall clinical failure rate as a result of aseptic loosening of the femoral stem was 11.5%. Most failures occurred with smaller stems, especially in heavier patients. Clinical and radiographic data suggest that failure of femoral component fixation was due to high stresses in the cement mantle associated with the increased flexibility of the smaller stems. Radiographs of successful arthroplasties in patients with larger stems showed proximal stress shielding in most. The findings in this study do not support the contention that titanium alloys provide an advantage over more rigid materials in the manufacture of cemented femoral components for total hip arthroplasty.     

Staged bilateral total hip arthroplasty using rough and smooth surface femoral stems with similar design: 10-year survivorship of 48 cases

Background?Various studies have reported good long-term results using femoral stems with either smooth or rough surfaces. In this retrospective cross-sectional survivorship study, we reviewed the 10-year results of 51 bilateral staged cemented total hip arthroplasties using the Harvard or the Charnley femoral stems—which have almost similar geometry but a different surface finish.

Methods?51 patients were reviewed at median interval of 10 (Harvard group) and 11 years (Charnley group) after the primary operation. We evaluated cement mantle thickness, alignment of the components, presence of radiolucent lines, and aseptic loosening. Kaplan-Meier analysis was performed to calculate the survival rate using various endpoints.

Results?8 hips in the Harvard group were revised for aseptic loosening of thefemoral component at a median interval of 6.3 years after the primary procedure. 3 hips in the Charnley group were revised for aseptic loosening of the femoral and acetabular components between 10 and 11 years after the primary procedure. The 10-year survival rate for the femoral component using revision surgery for aseptic loosening as an endpoint was 80% (95% CI: 31–42) and 95% (95% CI: 44–47) in the Harvard and the Charnley group, respectively. Cox regression analysis did not reveal any statistically significant effect of various radiographical parameters on the survival rate (p < 0.05).

Interpretation?Our results demonstrate that in the group of patients studied, the femoral stem component with the matt surface finish had less satisfactory 10-year survival than the femoral stem of similar design which had a smooth surface finish.

?     

Gute langfristige Nachuntersuchungsergebnisse einer zementierten Titan-Geradschaftprothese

A higher-than-average rate of aseptic loosening has been postulated to be associated with the combination of a titanium stem and bone cement. In this prospective follow-up study we therefore investigated our first consecutive series of 250 implantations of a cemented femoral shaft prosthesis made of titanium alloy (BiCONTACT((R)), Aesculap, Tuttlingen, Germany).Average time of follow-up evaluation was 9.7 years (range 8.7-10.3 years). At follow-up, mean patient age was 81 years; 89 patients with 93 hips have deceased and two could not be located. Follow-up rate was 98.7% for the patients still alive at time of follow-up evaluation. Five patients have been revised, two for infection and one for aseptic loosening of a varus-malaligned stem; two radiologically well-fixed stems had been revised during acetabular revision. Survival estimate showed a calculated cumulative survival rate of 97.5% after 11 years [confidence limits: 99.0% (upper) and 94.1% (lower)]. The average Harris hip score at time of follow-up was 82.25 points.Radiologically, signs of loosening could be detected in 3 stems: in one case varus malalignement deteriorated with time and in 2 cases osteolyses developed together with significant polyethylene wear. All 3 patients experienced only mild pain and revision had not been indicated so far. In conclusion, the long-term follow-up results with this cemented titanium femoral component are encouraging and are comparable to other successful cemented femoral components in primary total hip arthroplasty. No increased risk for aseptical loosening was associated to the combination of titanium and cement in this specific stem. Design parameters seem to play an important role in the development of aseptic loosening in cemented titanium stems.     

Revision total hip replacement using cemented collarless double-taper femoral components

We investigated 219 revisions of total hip replacement (THR) in 211 patients using a collarless double-taper cemented femoral component. The mean age of the patients was 72 years (30 to 90). The 137 long and 82 standard length stems were analysed separately. The mean follow-up was six years (2 to 18), and no patient was lost to follow-up. Survival of the long stems to re-revision for aseptic loosening at nine years was 98% (95% confidence interval (CI) 94 to 100), and for the standard stems was 93% (95% CI 85 to 100). At five years, one long stem was definitely loose radiologically and one standard stem was probably loose. Pre-operative femoral bone deficiency did not influence the results for the long stems, and corrective femoral osteotomy was avoided, as were significant subsidence, major stress shielding and persistent thigh pain. Because of these reliable results, cemented long collarless double-taper femoral components are recommended for routine revision THR in older patients.     

Long-term outcome of cemented total hip arthroplasty with the Charnley-type femoral stem made of titanium alloy

BackgroundTotal hip arthroplasty is a successful treatment for hip diseases including osteoarthritis, osteonecrosis of the femoral head, and rheumatoid arthritis. Various designs of cemented femoral stems made of stainless steel and titanium alloy have been used. Among them, Charnley-type femoral stems made of stainless steel have often been reported to have good long-term outcome. However, the long-term outcome of the Charnley-type femoral stem made of Ti alloy is yet to be reported. We conducted a retrospective study to assess the long-term outcome of cemented primary total hip arthroplasty with the Charnley-type femoral stem made of Ti alloy.MethodsBetween October 1988 and February 1997, 341 cemented primary total hip arthroplasties with the Charnley-type femoral stem made of Ti alloy were consecutively performed in our hospital. Among these, 164 patients (211 hips) who underwent this procedure were followed up for more than 12 years, and the surgical hips were analysed clinically and radiologically. The mean follow-up period was 20.6 years. Kaplan–Meier survival analyses were performed to assess femoral component survival. Factors affecting stem revision for aseptic loosening were also investigated using log-rank tests.ResultsIn the functional assessment, the preoperative Japanese Orthopaedic Association score significantly improved from 47.2 points preoperatively to 79.0 points at the final follow-up. Eventually, 33 femoral stems were revised, of which 12 were revised for aseptic loosening. In the Kaplan–Meier survival analysis, the 20-year survival rates with stem revision for aseptic loosening and radiological stem loosening at the end points were 95.9% and 97.1%, respectively. Original diagnosis (non-osteoarthritis) was the only significant factor for aseptic loosening of the femoral stem.ConclusionsCemented primary total hip arthroplasty with the Charnley-type femoral stem made of Ti alloy showed excellent outcomes for more than 20 years.     

Comparison between straight- and curved-stem Müller femoral prostheses. 5- to 10-year results of 545 total hip replacements

Between 1977 and 1982, 545 cemented femoral prostheses were implanted, in combination with a noncoated cementless polyethylene acetabular component (RM cup). Three hundred and eighty-one straight-stem and 76 curved-stem Müller femoral components were implanted, as well as 88 collared components with a 130-mm stem and a 130 degrees neck-shaft angle, derived from a long-stem steel prosthesis. Survivorship analysis of revisions for aseptic loosening at 10 years revealed 97% straight-stem survival, 91.6% curved-stem survival, and 88.3% 130 degrees stem survival. "Survival" curves were also constructed for radiological loosening, and the survival rates (patients without radiological evidence of loosening) were 69.8%, 78.8%, and 63.1% respectively at 10 years. The 130 degrees collared stem was associated with significantly less acetabular loosening than the other prostheses. This resulted in less calcar resorption, but there was a higher rate of stem loosening. Acetabular loosening and associated wear products appear to be responsible for calcar resorption, and stress shielding of the calcar appears to be of minor importance in the pathogenesis of aseptic stem loosening. Better cementing techniques have improved survivorship of the curved-stem prosthesis, and early fears of high rates of radiological loosening with the straight stem have not been substantiated.     

Excellent Long-Term Survival Rate of Polished,Tapered, Cemented Stems in Patients Aged 35 Years or Younger With Avascular Necrosis or Inflammatory Arthritis of the Hip

BackgroundTotal hip arthroplasty (THA) for avascular necrosis (AVN) or inflammatory arthritis (IA) comes with a relatively high risk of aseptic stem loosening, especially in young patients. There are limited long-term data on the survivorship of polished, tapered, cemented stems in this population. We therefore performed a single-center retrospective study investigating the survival of this particular stem type in young patients with AVN or IA.MethodsAll patients aged ≤35 years who had received a THA for AVN or IA operated on by the senior author between 1990 and 2010 at the University Hospitals Leuven were identified. In total, 85 THAs in 62 patients were included. Primary endpoint was revision of the femoral component for aseptic loosening. Secondary endpoints were revision of the acetabular component for aseptic loosening, revision for other reasons, and the presence of radiolucencies around the components.ResultsThe mean follow-up for the entire cohort was 18.0 ± 5.3 years (range 8.0-28.9). Taking revision for aseptic loosening as endpoint, the survival of cemented stems was 100% after 15 years and 95.1% after 20 years. Survival of uncemented cups (91.3%) was significantly better than survival of cemented cups (50.3%) after 20 years of follow-up for aseptic loosening. Taking revision for any reason as endpoint, the survival of THAs with uncemented and cemented cups was 90% and 43.1% at 20 years respectively. Radiolucencies developed in the cement mantles around 11 of the 81 nonrevised stems, mainly in zones 1 and 7.ConclusionIn this cohort of young patients with high-risk profiles for aseptic stem loosening, polished, tapered, cemented stems showed excellent long-term survival rates and they therefore remain a viable alternative to uncemented stem designs.     

Less wear with aluminium-oxide heads than cobalt-chrome heads with ultra high molecular weight cemented polyethylene cups: A ten-year follow-up with radiostereometry

Purpose  

Wear is a major contributor to osteolysis and aseptic loosening of total hip replacements (THR). Both alumina (Al₂O₃) and cobalt-chrome (CoCr) femoral heads are commonly used. We investigated wear comparing alumina heads to cobalt-chrome heads against conventional cemented polyethylene (PE) cups for up to ten years.     

Aseptic loosening of straight-and curved-stem Müller femoral prostheses

Summary Out of 1099 Müller total hip prostheses with straight and curved stems consecutively implanted between 1980 and 1984, those performed in as homogeneous a group as possible of patients under the age of 70 years were selected for the present retrospective study. There were 158 straight femoral stems with cementless RM acetabular cups, 105 straight stems with cemented Müller acetabular cups, and 158 curved stems with cemented Müller acetabular cups, and their results over a mean follow-up period of 5.8 ± 1.24 years were compared. Six (3.7%) curved and 5 (1.9%) straight-stem prostheses were exchanged due to aseptic loosening; 26 (16.3%) curved and 54 (20.1%) straight-stem prostheses were at risk or loose at the time of follow-up. Survival curves show a worse result for straight stems after 6 years; within a follow-up period of 6–8 years there was significantly more radiological loosening in straight stems than in curved. Loosening in straight stems is assumed to develop mainly as a physiological reaction to the presence of bone cement particles.     

Results of a cemented straight titanium alloy femoral stem after mean follow-up of 13 years

The first consecutive series of 250 implantations of a cemented femoral shaft prosthesis made of titanium alloy (Bicontact®, Aesculap, Tuttlingen, Germany) in 239 patients are included in this prospective follow-up study. Average time of follow-up evaluation was 12.6 years (range 11.8–13.8 years). At follow-up, 116 patients with 112 hips have died and only two could not be located. Follow-up rate was 99.2% for the patients still alive at time of follow-up evaluation. Eight patients have been revised, two for infection, one for aseptic loosening of a varus-malaligned stem and two for aseptic loosening in cases with osteolysis; two radiologically well-fixed stems had been revised during acetabular revision. Two additional stems were regarded loose according to radiologic criteria. Survival estimate (with revision as an endpoint) showed a calculated cumulative survival rate of 95.8% after 14 years [confidence limits: 98.0% (upper) and 91.4% (lower)]. The average HARRIS hip score at time of follow-up was 77.3 points. Radiologically, signs of loosening could be detected in two stems: in both cases osteolyses developed together with significant polyethylene wear. One of these patients experienced severe pain, so an indication for revision is given, the other has only mild pain and revision had not been indicated so far. In conclusion, the long-term follow-up results with this cemented titanium femoral component are encouraging and are comparable to other successful cemented femoral components in primary total hip arthroplasty. No increased risk for aseptical loosening was associated with the combination of titanium and cement in this specific stem.     

Revision total hip arthroplasty with cemented femoral component

We reviewed retrospectively the results of 28 hips (25 patients) after revision of the femoral component with use of a cemented stem, because of aseptic loosening. The mean duration of follow-up was 4.43 years (range 2–12 years). Over the course of the study period, repeat revision was done in 4 hips after an average of 4.45 years. Three hips had a repeat revision of the femoral component because of aseptic loosening and one for a deep infection. The rate of loosening of the femoral component was 32.4% (9 hips) at an average of 5.22 years. The 5-year survival rate was 76.9% with mechanical failure as end point; and 90% with re-revision of femoral component because of aseptic loosening as end point. The cement mantle was the principal factor, which was significantly associated with a better survival rate of femur fixation (P < 0.05). No correlation was noted between quality of bone loss at the time of revision, bone graft or the use of long stems, and the survival rate of femoral component. By improving the cementing technique and in selected patients, the use of cemented femoral stem could be a good alternative for aseptic loosening THA.     

High revision rate after treatment of femoral neck fractures with an optionally (un)cemented stem

Background  The advantages of uncemented and cemented components in hip arthroplasty have been subject of debate. We have studied on a hemiprosthesis, which can be optionally implanted with or without cement. Since the stem geometry and surface in cemented arthroplasty differs from the uncemented one and cannot be fused into one general design, we hypothesised that this hemiprosthesis used without cement has a considerable high revision rate, based on aseptic loosening. Methods  A hemiprosthesis, which is designed for both cemented and uncemented fixation, was used (Conquest, Smith&Nephew). Preoperatively, the choice of whether to use cement or not was based on the shape and bone quality of the femoral canal. Revision rate and indication, mortality, perioperative complications and radiographic features of 151 consecutive hips in 146 patients were evaluated. Results  Twenty-three stems (15%) were implanted with cement and 128 (85%) without. After a mean follow-up of 2 years, a revision rate of 8.6% and a survival percentage of 90% (CI 85–95) were observed. Twelve uncemented stems warranted revision, compared with one cemented stem. Revision because of aseptic loosening was necessary in 7 (6%) stems, all uncemented. No differences in operation-related mortality and morbidity were observed. Conclusion  Because of the rather high revision rate, the authors advice not to use this hemiprosthesis without cement.     

Five-year results of two cemented hip stem models each made of two different alloys

Introduction The aim of this study was to compare the influence of two different cemented hip stems each made of two different alloys concerning survival and outcome.Materials and methods The 5-year results with 161 Mueller straight stems made of cobalt chromium (SS CoCr), 272 Mueller straight stems made of titanium (SS Ti), 233 Mueller SL stems made of titanium (SL Ti) and 255 SL stems made of cobalt chromium (SL CoCr) implanted consecutively in this order were compared. All patients were followed up prospectively during the first 5 years after implantation. The evaluation of the results was retrospective.Results The survival rates for aseptic loosening were 100% (SS CoCr), 92.8% (SS Ti), 81.6% (SL Ti) and 97.8% (SL CoCr). Clinical and radiological outcomes like pain occurrence, use of pain medication, ability to climb stairs, amount of stem subsidence and osteolysis correlated statistically significantly with the results of the survival rates. Concerning the two alloys, chromium cobalt showed better results, and concerning the two designs, the straight stem had a better outcome. For the four prostheses being compared, the results were influenced more by the alloy than by the design, and the small-sized titanium stems were more susceptible to undergoing revision than the large-sized prostheses.Conclusion Stem design and even more alloy may influence the survival rate and clinical outcome. Evaluating the results, we recommend the use of the classic straight stem prosthesis made of cobalt chromium.     

Cemented versus uncemented hip replacement--rational decision making using the BiCONTACT total hip system

The BiCONTACT femoral stem has been developed as a modular system which is suitable for both cemented and uncemented implantation. A highly standardized procedure using an identical set of instruments for both modes of fixation ensures bone preservation. Primary stability is achieved by special design parameters. The cementless implants are coated proximally, thus facilitating osteointegration and proximal load transfer. Cemented stems provide an identical design but a smooth surface and are anchored by a homogenous cement mantle. The BiCONTACT stem is in use in the BG Trauma Center Tuebingen since 14 years and a consecutive series of 250 cases (series A) with uncemented implantation and of 250 cases (series B) with cemented implantation has been analyzed in two different prospective follow-up studies. Long-term survival after 11 years was 97.1 % (95 % confidence limits: 93.8 %-98.7 %) for series A, the follow-up rate was 99.2 %. For series B, the follow up-rate was also 99.2 %, survival estimate after 11 years was 97.5 % (95 % CI: 94.2 %-99.0 %).     

Contemporary total hip arthroplasty with and without cement in patients with osteonecrosis of the femoral head

BACKGROUND: The rate of failure of primary total hip arthroplasty in patients with osteonecrosis of the femoral head is higher than that in patients with osteoarthritis. The purpose of this prospective study was to document the clinical and radiographic results of arthroplasty with so-called third-generation cementing and the results of second-generation cementless total hip arthroplasty in ninety-eight consecutive patients with osteonecrosis of the femoral head. METHODS: Fifty patients who had had simultaneous bilateral total hip arthroplasty with a cemented stem in one hip and a cementless stem in the other and forty-eight patients who had had a unilateral total hip arthroplasty with a cementless stem were included in the study. A cementless acetabular component was used in all hips. The presumed cause of the osteonecrosis was ethanol abuse in fifty-seven patients, unknown in twenty-seven, fracture of the femoral neck in nine, and steroid use in five. There were eighty men and eighteen women. The mean age at the time of the arthroplasty was 47.3 years (range, twenty-six to fifty-eight years). Clinical and radiographic evaluations were performed preoperatively; at six weeks; at three, six, and twelve months; and yearly thereafter. The average duration of follow-up was 9.3 years. RESULTS: The average Harris hip scores in the group treated with unilateral arthroplasty (97 points) and the group treated with bilateral arthroplasty (94 points) were similar at the time of final follow-up. They were also similar between the group treated with cement (mean, 96 points) and that treated without cement (95 points). No component had aseptic loosening in either group. In one hip, a cemented femoral stem (2%) and a cementless cup were revised because of infection. Two cementless stems (2%) were revised because of fracture of the proximal part of the femur with loosening of the stem. Annual wear of the polyethylene liner averaged 0.22 mm in the group treated with cement (a zirconia head) and 0.14 mm in the group treated without cement (a cobalt-chromium head). The prevalence of osteolysis in zones 1 and 7 of the femur was 16% in the group treated with cement and 24% in the group treated without cement. CONCLUSIONS: Advancements in surgical technique and better designs have greatly improved the long-term survival of cemented and cementless implants in young patients with osteonecrosis of the femoral head. Although there was no aseptic loosening of the components, a high rate of linear wear of the polyethylene liner and a high rate of osteolysis in these high-risk young patients remain challenging problems.