Long-Term Survival of the Cemented Exeter Universal Stem in Patients 50 Years and Younger: An Update on 130 Hips

BackgroundThere is variable evidence regarding survivorship beyond 20 years of total hip arthroplasties in young patients. We report the long-term results of the Exeter cemented hip system in patients ≤50 years at minimum of 20 years.MethodsClinical and radiological outcomes of 130 consecutive total hip arthroplasties in 107 patients aged 50 years or younger at primary operation were reviewed; 77% had a diagnosis other than osteoarthritis. All patients were followed at 5-year intervals, no patients were lost to follow-up, and the status of every implant is known.ResultsMean age at surgery was 41.8 (17-50) years. Mean follow-up was 22.0 (20.0-26.1) years. There were 79 hips surviving, 14 hips (11 patients) deceased, and 37 hips revised. Reasons for revision: 29 hips for aseptic cup loosening (26 stems revised using cement-in-cement, three left in-situ); three stems for femoral osteolysis, two related to acetabular polyethylene wear (14.1 and 17.0 years), one with Gaucher’s disease (21.1 years); one broken stem (12.9 years); one cup for instability (4.3 years–stem revised using cement-in-cement); and two hips with infection (8.5 and 23.8 years). There were no cases of aseptic loosening of the Exeter stem. There were no radiologically loose stems although eight patients had radiological evidence of loosening of the cemented cup. Survivorship at 22 years was 74.9% for revision for all causes and 96.3% for revision of the stem for aseptic loosening or lysis.ConclusionThe Exeter cemented stem has excellent survivorship at minimum 20 years in young patients. Acetabular component survivorship was less favorable, but the advent of highly cross-linked polyethylene may improve this in the long term.     

Primary total hip arthroplasty with the Karl Zweymüller first-generation cementless prosthesis: A 5- to 9-year retrospective study

A consecutive series of 72 primary total hip arthroplasties were performed in 70 patients using the first-generation Zweymüller cementless titanium press-fit femoral and threaded acetabular components (AlloPro, Baar, Switzerland). Twelve hips were excluded from the study because of insufficient follow-up evaluation, including one patient who underwent a socket revision within the first 2 weeks. Sixty total hip arthroplasties with an average follow-up period of 80 months (range, 60–108 months) were retrospectively reviewed. Clinical results were graded excellent or good in 54 cases (90%), fair in 3 (5%), and poor in 3 (5%) with 2 early implant failures (1 acetabular cup and 1 femoral stem in 2 hips). Cumulative survival rates at the 6- to 7-year interval, with failure defined as revision and/or loosening are 98.47% (SD, 2.0%) for the femoral component (1 single septic and loose stem, revised at 5 years), 97.08% (SD, 2.72%) for the screw ring (2 unstable but only 1 revised), and 95.56% (SD, 3.36%) for both components. This encouraging experience with the first-generation prosthesis supports the rationale for continued use of the new Zweymüller Alloclassic stem and open-back screw ring available since 1988.     

Results of the uncemented total hip arthroplasty in avascular necrosis of the femoral head]

AIM OF THE STUDY: The results from 56 patients with osteonecrosis of the femoral head who underwent 66 uncemented total hip replacements were analyzed and compared with current reports in the literature on cemented endoprosthesis. METHODS: In the retrospective study in 30 of those cases the Zweymüller and in 25 cases the HA-coated ABG prosthesis were used. In addition the results of 11 patients with a polyethylene Endler cup in combination with a Zweymüller stem are presented. The mean age at surgery was 48 years, the mean follow-up was 5.9 years. Clinical examination, registration of the Merle d'Aubigné score and a radiological examination were performed. RESULTS: The clinical results did not show any differences between the used prostheses. A more favourable outcome with regard to the Merle d'Aubigné score was demonstrated for the Zweymüller and ABG prostheses. No loosening of the stem was found. Revision as a consequence of aseptic loosening of the acetabular component was done in 7,5 % (27,3 % of the Endler cups and 8 % of the ABG cups). 20 % of the patients with an ABG prosthesis showed acetabular osteolysis of various degrees. This seems to be correlated with an increased polyethylene wear. CONCLUSION: Recent reports in the literature about a favourable outcome in uncemented total hip arthroplasty in osteonecrosis of the femoral head can be confirmed. The unsatisfactory results of the Endler cup indicate that established types of endoprostheses should be preferred.     

The Result of Revision Total Hip Arthroplasty in Patients with Metallosis Following a Catastrophic Failure of a Polyethylene Liner

BackgroundWear cannot be completely prevented after total hip arthroplasty. If severe polyethylene (PE) liner wear develops, the so-called catastrophic failure occurs and metallosis develops. We postulated that longevity of the new implant may be affected after revision surgery for metallosis following a catastrophic failure of a PE liner due to the substantial amount of PE wear particles and infiltration of the metal particles in this catastrophic condition.MethodsTwenty-three hips of 23 patients were identified because they showed metallosis during revision total hip arthroplasties performed in Seoul National University Hospital between January 1996 and August 2004. They were followed for at least 6.5 years after the index revision total hip arthroplasty. The clinical and radiological results of revision total hip arthroplasties in these patients were evaluated.ResultsThe median Harris hip score increased from 60 points before revision total hip arthroplasties to 90 points at the final follow-up. Osteolysis was detected at an average of 9.3 years after revision total hip arthroplasties in 13 hips and acetabular cup loosening at average 9.8 years after revision total hip arthroplasties in 9 hips. With radiographic evidence of osteolysis and loosening as the end points, the 15-year survival rates were 28.2% and 56.0%, respectively.ConclusionsThe survival rate of revision total hip arthroplasty in patients with metallosis following a catastrophic failure of a PE liner was low.     

High wear rates and extensive osteolysis in 3 types of uncemented total hip arthroplasty: A review of the PCA,the Harris Galante and the Profile/Tri-Lock Plus arthroplasties with a minimum of 12 years median follow-up in 96 hips

Background?High wear rates and femoral and acetabular osteolysis have been—and still are—the main problems in uncemented total hip replacement. We reviewed 96 consecutive cementless total hip replacements of 4 different designs.

Patients and methods?21 PCA, 25 Harris Galante Porous/Harris Galante I (stem/cup), 25 Profile pressfit/ Tri-Lock Plus (stem/cup) and 25 Profile HA-coated/Tri-Lock Plus (stem/cup) prostheses were included. The operations were performed in the period 1984–1991. Median follow-up ranged from 12–16 years. Wear and osteolysis were measured.

Results?Mean linear wear rates ranged from 0.17 to 0.21 mm/year in the 4 groups, and there were no statistically significant differences between the groups (p = 0.9, ANOVA). Moderate or extensive osteolysis was found in 46 of the 96 hips included. The association between high and low wear rates (more or less than 0.20 mm/ year) and extent of osteolysis was statistically significant (p < 0.001, t-test). We found poor 12-year survival of the primary prostheses in all 4 groups (50–70%), mainly due to revisions because of wear of the polyethylene liner and/or osteolysis. The infrequently documented Profile/Tri-Lock Plus systems did not perform differently from the PCA and the HG.

Interpretation?The poor long-term results with these uncemented total hip arthroplasties illustrate the necessity of regular radiographic evaluation in order to detect osteolysis and liner failure, which are both generally asymptomatic until catastrophic failure appears.     

Cementless total hip arthroplasty with the rectangular titanium Zweymuller stem. A concise follow-up, at a minimum of fifteen years, of a previous report

Between October 1986 and November 1987, 208 total hip arthroplasties were performed with use of the cementless Zweymüller stem and a threaded cup in 200 consecutive patients. Of 102 patients (108 hips) who were available for follow-up at a minimum of 180 months postoperatively, eighty-three (eighty-nine hips) had the primary joint replacement still intact. No stem had been revised because of aseptic loosening, but we found various degrees of osteolysis around sixteen (18%) of the implants. The probability of survival of the stem at fifteen years was 0.98 (95% confidence interval, 0.96 to 1.00). The probability of survival of the cup was 0.85 (95% confidence interval, 0.79 to 0.91).     

Ten to twelve-year results with the Zweymüller cementless total hip prosthesis

Between January 1987 and December 1990, 221 Zweymüller cementless total hip arthroplasties were performed in 211 patients with idiopathic osteoarthritis. A total of 136 patients (142 prostheses) were evaluated at a mean follow-up of 134 months (SD 9.5). The study group consisted of 78 Hochgezogen and 64 Stepless stem prostheses, all with a threaded titanium cup and ceramic head. No clinical and radiological differences were found between the 2 stem prostheses. Seven cups had been revised because of aseptic loosening; 17 cups showed radiolucent lines, osteolysis, or migration. Mean linear polyethylene wear of 105 (74%) cups was 0.46 mm (SD 0.27), with an annual wear of 0.04 mm (SD 0.02). Wear did not correlate with pain, cup migration, radiolucent lines, or osteolysis. Cumulative survival was 96%. Zweymüller cementless total hip arthroplasty showed good midterm results.     

Total hip replacement in younger patientsSurvival rate after avascular necrosis of the femoral head

Background?A high risk of loosening has been reported in replacements performed because of avascular necrosis.Patients and methods?To study cementless total hip replacement (THR) in younger patients with avascular necrosis (AVN), we analyzed retrospectively the outcome in 129 cases: 46 Mittelmeier monobloc ceramic hips (22 cases with AVN), and 83 Zweymüller total hip systems (35 cases with AVN) clinically and radiographically.Results?At follow-up, 17 Mittelmeier prostheses (10 AVN) and 4 Zweymüller prostheses (none with AVN) had been revised. The diagnosis did not affect the implant survival, but the Zweymüller THR fared better than the Mittelmeier system. The main reason for revision of Mittelmeier implants was aseptic loosening, 3 of 4 Zweymüller revisions were necessary due to polyethylene wear. This difference was confirmed by the radiographic evaluation of the still intact implants: Zweymüller THR showed better values for signs of osseointegration, radiolucent lines around the implants and migration, but more acetabular wear. None of these differences was affected by the AVN diagnosis.Interpretation?We could not confirm that AVN is a risk factor in total hip replacement.     

Total hip replacement in younger patients: survival rate after avascular necrosis of the femoral head

BACKGROUND: A high risk of loosening has been reported in replacements performed because of avascular necrosis. PATIENTS AND METHODS: To study cementless total hip replacement (THR) in younger patients with avascular necrosis (AVN), we analyzed retrospectively the outcome in 129 cases: 46 Mittelmeier monobloc ceramic hips (22 cases with AVN), and 83 Zweymüller total hip systems (35 cases with AVN) clinically and radiographically. RESULTS: At follow-up, 17 Mittelmeier prostheses (10 AVN) and 4 Zweymüller prostheses (none with AVN) had been revised. The diagnosis did not affect the implant survival, but the Zweymüller THR fared better than the Mittelmeier system. The main reason for revision of Mittelmeier implants was aseptic loosening, 3 of 4 Zweymüller revisions were necessary due to polyethylene wear. This difference was confirmed by the radiographic evaluation of the still intact implants: Zweymüller THR showed better values for signs of osseointegration, radiolucent lines around the implants and migration, but more acetabular wear. None of these differences was affected by the AVN diagnosis. INTERPRETATION: We could not confirm that AVN is a risk factor in total hip replacement.     

Cementless total hip arthroplasty in patients with severely dysplastic hips and a previous Schanz osteotomy of the femur

Background and purpose Historically, a Schanz osteotomy of the femur has been used to reduce limp in patients with severely dysplastic hips. In such hips, total hip arthroplasty is a technically demanding operation. We report the long-term results of cementless total hip arthroplasty in a group of patients who had all undergone a Schanz osteotomy earlier.

Patients and methods From 1988 through 1995, 68 total hip replacements were performed in 59 consecutive patients previously treated with a Schanz osteotomy. With the cup placed at the level of the true acetabulum, a shortening osteotomy of the proximal part of the femur and distal advancement of the greater trochanter were performed in 56 hips. At a mean of 13 (9–18) years postoperatively, we evaluated these patients clinically and radiographically.

Results The mean Harris hip score had increased from 51 points preoperatively to 93 points. Trendelenburg sign was negative and there was good or slightly reduced abduction strength in 23 of 25 hips that had not been revised. There were 12 perioperative complications. Only 1 cementless press-fit porous-coated cup was revised for aseptic loosening. However, the 12-year survival rate of these cups was only 64%, as 18 cups underwent revision for excessive wear of the polyethylene liner and/or osteolysis. 6 CDH femoral components had to be revised due to technical errors.

Interpretation Our results suggest that cementless total hip arthroplasty combined with a shortening osteotomy of the femur and distal advancement of the greater trochanter can be recommended for most patients with a previous Schanz osteotomy of the femur. Because of the high incidence of liner wear and osteolysÍs of modular cementless cups in this series, nowadays we use hard-on-hard articulations in these patients.     

Results of 3,668 primary total hip replacements for primary osteoarthritis in patients under the age of 55 years

Background and purpose In a previous study based on the Finnish Arthroplasty Register, the survival of cementless stems was better than that of cemented stems in younger patients. However, the survival of cementless cups was poor due to osteolysis. In the present study, we analyzed population-based survival rates of the cemented and cementless total hip replacements in patients under the age of 55 years with primary osteoarthritis in Finland.

Patients and methods 3,668 implants fulfilled our inclusion criteria. The previous data included years 1980–2001, whereas the current study includes years 1987–2006. The implants were classified in 3 groups: (1) implants with a cementless, straight, proximally circumferentially porous-coated stem and a porous-coated press-fit cup (cementless group 1); (2) implants with a cementless, anatomic, proximally circumferentially porous-coated stem, with or without hydroxyapatite, and a porous-coated press-fit cup with or without hydroxyapatite (cementless group 2); and (3) a cemented stem combined with a cemented all-polyethylene cup (the cemented group). Analyses were performed separately for 2 time periods: those operated 1987–1996 and those operated 1997–2006.

Results The 15-year survival for any reason of cementless total hip replacement (THR) group 1 operated on 1987–1996 (62%; 95% CI: 57–67) and cementless group 2 (58%; CI: 52–66) operated on during the same time period was worse than that of cemented THRs (71%; CI: 62–80), although the difference was not statistically significant. The revision risk for aseptic loosening of cementless stem group 1 operated on 1987–1996 (0.49; CI: 0.32–0.74) was lower than that for aseptic loosening of cemented stems (p = 0.001).

Interpretation Excessive wear of the polyethylene liner resulted in numerous revisions of modular cementless cups. The outcomes of total hip arthroplasty appear to have been relatively unsatisfactory for younger patients in Finland.     

Total hip arthroplasty with use of the cementless Zweymüller Alloclassic system. A ten to thirteen-year follow-up study

BACKGROUND: The Zweymüller Alloclassic total hip arthroplasty system is widely used, although few intermediate-term studies have been published. The purpose of the present study was to evaluate the clinical and radiographic results of this system after ten years. METHODS: One hundred and twenty-four consecutive primary total hip arthroplasties were performed with the Zweymüller Alloclassic cementless system at our institution between February 1988 and March 1991, and 104 hips (ninety-four patients) were retrospectively reviewed after a minimum duration of follow-up of ten years. The mean age of the patients at the time of the arthroplasty was 62.3 years (range, twenty-five to seventy-seven years). The mean duration of follow-up was 11.3 years. Standard radiographs were made for all patients immediately after the operation, at six and twelve months, and annually thereafter for at least ten years. Cox multivariate regression analysis was performed to assess the influence of various factors on survival of the implant. RESULTS: The cumulative probability of not having a revision of any prosthetic component for any reason was 94.1% (95% confidence interval, 91.9% to 96.3%) at twelve years in the best-case scenario and 85.3% (95% confidence interval, 82.1% to 88.5%) at twelve years in the worst-case scenario for the entire series of 124 hips. Among the 104 hips in the follow-up study, three acetabular components and no stems were revised. Two hips had level-4 pain according to the system of Merle D'Aubigné and Postel. Seven acetabular components (7%) were loose at twelve years, and all stems had radiographic evidence of stable fixation. Acetabular cup loosening was related to a vertical cup angle (p = 0.0008, Student t test), acetabular wear of > or =1 mm (p = 0.001, Fisher exact test), and a 32-mm femoral head (p = 0.001, Fisher exact test). Although femoral osteolysis was seen in eighteen hips (17%) at twelve years, all osteolytic cavities were proximal and focal. CONCLUSIONS: The Zweymüller Alloclassic prosthesis, particularly its femoral stem, demonstrated good results and durable fixation at a minimum of ten years of follow-up.     

High wear rates and extensive osteolysis in 3 types of uncemented total hip arthroplasty: a review of the PCA, the Harris Galante and the Profile/Tri-Lock Plus arthroplasties with a minimum of 12 years median follow-up in 96 hips

BACKGROUND: High wear rates and femoral and acetabular osteolysis have been-and still are-the main problems in uncemented total hip replacement. We reviewed 96 consecutive cementless total hip replacements of 4 different designs. PATIENTS AND METHODS: 21 PCA, 25 Harris Galante Porous/Harris Galante I (stem/cup), 25 Profile pressfit/ Tri-Lock Plus (stem/cup) and 25 Profile HA-coated/Tri-Lock Plus (stem/cup) prostheses were included. The operations were performed in the period 1984-1991. Median follow-up ranged from 12-16 years. Wear and osteolysis were measured. RESULTS: Mean linear wear rates ranged from 0.17 to 0.21 mm/year in the 4 groups, and there were no statistically significant differences between the groups (p = 0.9, ANOVA). Moderate or extensive osteolysis was found in 46 of the 96 hips included. The association between high and low wear rates (more or less than 0.20 mm/ year) and extent of osteolysis was statistically significant (p < 0.001, t-test). We found poor 12-year survival of the primary prostheses in all 4 groups (50-70%), mainly due to revisions because of wear of the polyethylene liner and/or osteolysis. The infrequently documented Profile/Tri-Lock Plus systems did not perform differently from the PCA and the HG. INTERPRETATION: The poor long-term results with these uncemented total hip arthroplasties illustrate the necessity of regular radiographic evaluation in order to detect osteolysis and liner failure, which are both generally asymptomatic until catastrophic failure appears.     

双锥面螺旋臼固定治疗髋关节中心性脱位的中长期临床效果分析

目的 探讨使用双锥面螺旋臼假体固定髋关节中心性脱位病例的长期临床效果.方法 1998年5月至2006年9月北京大学人民医院关节病诊疗研究中心对31例髋关节中心性脱位患者的39侧髋关节行人工全髋关节置换术或翻修术,其中男性12例,女性19例.手术时平均年龄为57.6岁(30～82岁).引起髋关节中心性脱位的病因包括:类风湿关节炎3例6髋;股骨头坏死继发髋关节炎7例12髋,人工股骨头置换术后髋臼磨损11例11髋、髋臼假体松动10例10髋.术中髋臼部分均使用双锥面螺旋臼进行生物学固定.术前Harris评分平均为31.0分(14～61分).结果 所有病例均在术后6个月、1年时随访,2例3髋患者分别因肺癌、急性心肌梗死死亡.24例31髋获得随访,平均随访时间7.4年(5.0～11.5年).末次随访时Harris评分平均为84.7分(70～95分).1例股骨头坏死行双髋同时置换患者术后右髋出现感染,行关节取出骨水泥旷置术,但因内科疾病不稳定未再行翻修术.1例类风湿关节炎患者双髋关节分期手术,术后7年随访时左侧髋臼假体有内侧轻度移位,边缘有透亮线,但患者日常功能好,无疼痛.其余所有病例双锥面螺旋臼假体全部存留,患者日常生活功能良好,对手术效果满意.结论 髋关节中心性脱位使用双锥面螺旋臼的固定效果确切,平均超过7.4年的中长期随访结果显示效果良好.

Abstract：

Objective To discuss long-term clinical results of using Zweymüller cup to treat protrusio acetabuli. Methods From May 1998 to September 2006, 31 patients with 39 hips diagnosed protrusio acetabuli were treated with Zweymtüller cup in total hip arthroplasties or revisions. There were 12 men and 19 women with average age of 57.6 years (from 30 to 82 years). The reasons causing protrusio acetabuli were as followed: rheumatoid arthritis 3 cases 6 hips, osteoarthritis followed femoral head necrosis 7 cases 12 hips, acetabular wear after hemi-arthroplasty 11 cases 11 hips and acetabular component Results All cases were followed up 6 months and one year after operations. Two patients with 3 hips were died for lung cancer and acute myocardial infarction respectively. Twenty-four cases with 31 hips got recent follow-up with average 7. 4 years (from 5.0 to 11.5 years). The average Harris score improved from 31.0 (from 14 to 61) preoperatively to 84. 7(from 70 to 95) postoperatively. There was one infection in right hip after bilateral hip arthroplasty treating by removel prosthesis and cement spacer insert. But until now this patient still did not get revision for her internal medicine. One rheumatoid arthritis patient with two-stage bilateral hip arthroplasty was found slight internal migration and loosening line of left acetabular component,but the patient had no pain with good hip function. All other cases had good hip functions and were very fixations and perfect medium and long-term clinical results for over 7.4 years.     

High osteolysis and revision rate with the hydroxyapatite-coated ABG hip prostheses65 hips in 56 young patients followed for 5–9 years

Background?There are few reports on the outcome of uncemented HA-coated cups in young patients.Patients?I evaluated the 7-year (5–9) results of HA-coated hip prosthesis (ABG, Stryker) in a consecutive series of 65 primary arthroplasties on 56 patients (mean age 44 years). 2 patients were lost to follow-up and 3 died.Results?The cumulative survival rate with revision for any reason as endpoint at 9 years was 98% (95% CI, 96–100) for the stem, 69% (61–77) for the acetabular metal backing, and 59% (50–67) for the polyethylene liner. 15 of 65 cups were revised on average 6 years after the primary operation and 3 more are planned. Revisions were done in 3 hips because of loosening and migration of the cup, and in 12 hips because of wear and progressive osteolysis around stable components. Only hips with migration had clinical symptoms. Visual inspection of polyethylene liners revealed wear of the articulation in all cases, loosening of the locking mechanism in 10 cases and nonarticular surface deformity in 7 hips. All original stems are in situ although femoral osteolysis was seen in 12 cases and 1 hip was reoperated because of periprosthetic traumatic fracture. Despite the high revision rate, the clinical improvement was good: the average pre- and postoperative Harris Hip Scores at the most recent follow-up were 41 and 90, respectively.Interpretation?While the results on the femoral side were good, the survival rates of the acetabular cups were poor and we stopped using ABG I hip prostheses.     

非骨水泥型髋假体进行髋关节翻修的四年随访研究

目的　评价非骨水泥型髋关节系统治疗人工全髋关节翻修术的术后中期临床随访效果。方法　自1996年11月至2001年1月,对55例56髋关节行翻修术,采用了Zweymüller非骨水泥人工髋关节系统,年龄30~80岁,平均59岁。均有至少两年以上的临床和放射学追踪资料,平均随访时间4年。结果　32例32髋得到随访, 23例24髋失访。有3例出现围手术期并发症: 1例为假体取出时大转子骨折, 1例为术后2d脱位并成功闭合复位, 1例为伤口深部感染需要再次清创。无髋臼及股骨柄假体需要再度翻修。Harris评分由术前平均40 6分提高到最末次随访平均80 4分。X线片示髋臼和股骨柄假体位置满意,无松动和感染征象,周围骨质内向长入。结论　中期临床结果显示,初次用骨水泥和非骨水泥固定人工髋关节置换失败的病例,若髋臼环完整,使用非骨水泥型髋关节假体可以获得良好的临床效果。     

Porous-coated cups fixed with screws: a 12-year clinical and radiostereometric follow-up study of 50 hips

Background Excellent mid-term results have stimulated the use of hemispherical porous-coated cups in hip replacement. With longer follow-up, there have been problems related to polyethylene wear and liner fixation, and osteolysis has been documented in reports of selected cases. We evaluated the clinical and radiographic results of 50 patients followed for 12 years.

Patients and methods 58 consecutive patients (58 hips), mean age 55 years, were operated with Harris-Galante (HG) I or II cups using line-to-line fit and additional screw fixation. Polyethylene linersγ-sterilized in air and 32-mm ceramic heads were used. 8 patients died within 12 years, leaving 50 patients with a complete 12year follow-up. 23 of the cups were also evaluated with radiostereometry (RSA) for migration, liner stability, and wear.

Results All metal shells were still in situ after 12 years. 4 hips had been revised due to femoral loosening. In these revisions, the liner had been exchanged due to wear and/or instability, resulting in a cup survival rate of 89%. 28 cups displayed osteolytic lesions, mainly in relation to screws. RSA revealed minimum translations, but in many cases there were pronounced liner rotations suggesting unstable liners within the metal shell. The annual proximal wear was 0.09 mm and the three-dimensional wear was 0.16 mm.

Interpretation RSA can predict the long-term performance of cup fixation. Low migration during the initial years after implantation indicates excellent long-term results regarding fixation of the metal shell. The main problem with this design appears to be liner instability and osteolysis, factors that are probably interrelated. Because these phenomena are clinically silent, we recommend regular follow-up of patients with HG cups to avoid sudden loosening and complicated revisions.     

Midterm Clinical and Radiographic Outcomes of a Contemporary Monoblock Dual-Mobility Cup in Uncemented Total Hip Arthroplasty

BackgroundThe efficacy of contemporary monoblock dual-mobility (DM) cups to prevent dislocations in total hip arthroplasty (THA) is well reported, but there is little published data on their mid- to long-term outcomes. The authors aimed at reporting the 10-year survival of a contemporary DM cup as well as its clinical and radiographic outcomes.MethodsFrom a retrospective consecutive multicentric series of 516 patients (541 hips) that received uncemented THA between June 2007 and June 2010, 6 patients (6 hips) had cup and stem revisions, 5 patients (5 hips) had isolated stem revision, and 2 patients (2 hips) had isolated insert revision. A total of 103 patients (111 hips) died with their original implants, and 41 patients (42 hips) were lost to follow-up. This left 358 patients (375 hips) for clinical assessment at a median follow-up of 8.7 years (range, 6.8-10.5 years), including 279 patients (290 hips) with postoperative radiographs. Implant survival was calculated using the Kaplan-Meier method, and multivariable analyses were performed to determine whether clinical outcomes are associated with patient or surgical factors.ResultsThe 10-year survival considering revision for aseptic loosening as end point was 100% for the cup and 99.2% for the stem. No dislocations were observed, and radiographic assessment revealed 1 acetabular granuloma (0.3%), but no radiolucencies nor fractures. The Harris hip score improved from 49.6 ± 15.5 to 85.2 ± 14.5, and the postoperative Oxford hip score was 19.2 ± 7.6. Multivariable analyses revealed that improvement in Harris hip score increased with cup diameter (beta, 1.28; P = .039).ConclusionOur data confirmed satisfactory midterm outcomes of uncemented THA using a contemporary DM cup, with no dislocations nor cup revisions due to aseptic loosening.Level of EvidenceLevel IV, retrospective cohort study.     

Midterm results of primary total hip arthroplasty using highly cross-linked polyethylene: minimum 7-year follow-up study

The purpose of this study was to investigate the results of 113 total hip arthroplasties in 109 patients using highly cross-linked polyethylene (HXLPE) after midterm (minimum 7 years) follow-up retrospectively. The mean age at the time of operation was 57 years. Preoperative diagnosis was osteonecrosis in 81 hips and other diagnosis in 32 hips. There was no component loosening. Acetabular osteolysis was found in 12 hips (10.6 %). Mean linear HXLPE wear rate was 0.031 ± 0.012 mm/y. We analyzed the relationship between HXLPE wear rate and several variables influencing HXLPE wear. Only the cup position was related with wear rate of HXLPE significantly (P < .05). The results of total hip arthroplasties using HXLPE showed excellent results with decreased wear rate and low incidence of osteolysis after midterm follow-up.     

H/G非骨水泥人工全髋关节置换术后聚乙烯内杯磨损临床研究

目的 对H/G非骨水泥人工全髋关节置换术后聚乙烯内杯的磨损及髋臼周围骨溶解的情况进行总结.方法 我院1991至1995年共进行58例(65髋)H/G非骨水泥人工全髋关节置换,其中35例(40髋)获得10年以上随访.对这35例(40髋)患者获得随访的病例,采用计算机数字化方法测量髋臼聚乙烯内杯的二维线性磨损.结果 35例40髋均有不同程度的磨损,磨损范围2～8 mm,平均磨损为(0.32±0.31)mm/年.10髋聚乙烯磨损超过6 mm,髋臼假体周围的骨溶解严重,并伴有金属假体的移位,其中5髋聚乙烯内杯完伞磨透,金属股骨头与金属髋臼相接触;5髋聚乙烯内杯磨损严重伴明显骨溶解,内杯松动.2髋聚乙烯内杯脱位.共实施翻修手术12例,包括更换聚乙烯内杯和金属股骨头2例、金属闩杯翻修2例、全髋翻修8例.28髋在髋臼侧发现骨溶解,其中14髋股骨侧亦有骨溶解发生.结论 本组病例所观测到的H/G髋臼聚乙烯内杯的磨损程度超过文献所报道,而且由于磨损产生的大量磨屑,导致假体周围出现明显骨溶解,直接影响到假体的稳定.关节置换术后应定期随访,避免出现严重骨溶解后增加翻修手术的困难.