Serum interleukin 8 levels correlate with synovial fluid levels in patients with aseptic loosening of hip prosthesis

Levels of inflammatory cytokines (tumor necrosis factor alpha, interleukin [IL] 6, and IL-8) in serum from patients with osteolysis on radiographs after hip arthroplasty [osteolysis(+), n = 28], patients without osteolysis after hip arthroplasty [osteolysis(-), n = 24], and nonoperated healthy subjects [controls, n = 20] were determined. In addition, cytokine levels in synovial fluid from patients undergoing revision total hip arthroplasty (n = 14) for loosening were measured and compared with each other and with the area of osteolysis on radiographs. Serum IL-6 and IL-8 levels were significantly higher in the osteolysis(+) group than in the osteolysis(-) or the control groups. Furthermore, a significant correlation was found between the serum and synovial fluid IL-8 levels and between synovial fluid IL-8 levels and the area of osteolysis in patients undergoing revision total hip arthroplasty. Therefore, serum IL-8 levels could be a useful periprosthetic osteolysis marker.     

Collagen crosslinked N-telopeptides as markers for evaluating particulate osteolysis: a preliminary study.

The purpose of this study was to determine whether a marker of bone resorption could be used noninvasively to diagnose and assess treatment of periprosthetic osteolysis. The crosslinked N-telopeptide marker of osteoclast-mediated bone resorption potentially has the sensitivity to detect periprosthetic osteolysis. Second-morning urine specimens were obtained from (a) seven age-matched controls, (b) eight patients who had a hip arthroplasty, hybrid implants at least 1 year after surgery, and no osteolysis, (c) 11 patients who had a hip arthroplasty and osteolysis, and (d) 10 patients who had a hip arthroplasty and with osteolysis before and after 6 weeks of oral Fosamax (alendronate) treatment. The Fosamax treatment consisted of one 10-mg dose per day for 6 weeks. Men and young women (less than 40 years old) were chosen for this study to avoid bone resorption enhanced after menopause as a possible confounder. An enzyme-linked immunosorbent assay technique for quantifying crosslinked N-telopeptides of type-I collagen was performed on all specimens. The patients with osteolysis had significantly elevated levels of N-telopeptide compared with the implant control group. In addition, levels of N-telopeptide were significantly lowered after Fosamax treatment. These findings indicate that a systemic bone-resorption marker (N-telopeptide) can be used to evaluate local particulate-induced osteolysis and its treatment. The study also provides clinical evidence that osteolysis is associated with increased osteoclast-mediated bone resorption and that this locally induced bone resorption can be suppressed by certain bisphosphonates (Fosamax). These insights have potential value in the understanding and clinical management of aseptic loosening.     

Cementless Metasul metal-on-metal total hip arthroplasty in patients less than fifty years old

BACKGROUND: Durable results of total hip arthroplasty have been difficult to achieve in young patients. We reviewed the intermediate-term clinical and radiographic results in a series of active, higher-demand patients who were less than fifty years old when they underwent cementless total hip arthroplasty with the use of the Metasul metal-on-metal articulation. METHODS: Seventy total hip arthroplasties were performed in sixty-two patients who were younger than fifty years of age (average age, thirty-seven years). Two patients (two hips) had had a resection arthroplasty because of deep infection less than five years postoperatively and were excluded. Sixty patients (sixty-eight hips) were available for complete clinical and radiographic analysis after a mean duration of follow-up of seven years. RESULTS: The mean preoperative Harris hip score of 49 points improved to 95 points at the time of final follow-up; fifty-six patients (93%) had an excellent result. No component was seen to be loose radiographically at the time of final follow-up. Only one focal area of pelvic osteolysis in one patient and two small focal areas of femoral osteolysis in another patient were identified. The hip with focal pelvic osteolysis underwent revision surgery with a liner change and bone-grafting of the osteolytic lesion around a stable component. CONCLUSIONS: At a mean of seven years after arthroplasties with a Metasul metal-on-metal articulation, there was a low rate of osteolysis and aseptic loosening in this group of young patients. However, additional follow-up is necessary to determine any possible long-term deleterious effects associated with this metal-on-metal articulation.     

Assessment of Five Interleukins in Human Synovial Fluid as Possible Markers for Aseptic Loosening of Hip Arthroplasty

One of the most important factors that seems to be involved in total hip replacement is periprosthetic osteolysis. As it is well documented that several interleukins (ILs) are triggered in periprosthetic osteolysis, this article investigates the role of five ILs in primary and replacement total hip arthroplasty, understanding if one of them can also predict hip implant loosening, secondary surgery, and prosthesis breakage. The levels of IL-1α, 1β, 6, 8, and 10 in synovial fluid were examined, using a high sensitivity enzyme-linked immunosorbent assay (ELISA) test kit (Pierce Biotechnology, Inc., Rockford, IL, USA) to determine whether these cytokines could be used as markers of enhanced periprosthetic osteolysis, leading to aseptic loosening of total/partial hip arthroplasty or revision surgery. Synovial fluid was harvested from 23 patients undergoing primary total hip arthroplasty and 35 patients undergoing total/partial hip revision due to aseptic loosening. In the revision group, four cases had suffered a prosthesis fracture and five were second revisions. ILs 6 and 8 were significantly higher in the revisions (305 and 817 pg/mL) compared with the primary arthroplasties (151 and 151 pg/mL), including cases with prosthesis fracture and those requiring a second revision. IL-10 levels were lower (not significantly) in second revision samples compared with those of revision samples. IL-1β levels were significantly higher in prosthesis fracture samples compared with those of all the other revision samples. No statistically significant differences in IL levels were found between osteoarthritis samples and those of other diseases. These results are a step forward to elucidating the complex network of events that are involved in loosening of hip implants.     

无菌性松动全髋关节假体周围界膜组织中Caspase-3表达和细胞凋亡的研究

目的观察无菌性松动全髋关节假体周围界膜中凋亡调控蛋白Caspase-3表达和细胞凋亡分布的变化,探讨其与假体周围骨溶解之间的关系。方法2001年4月～2006年8月临床上选取16例高分子聚乙烯-金属配伍全髋关节翻修术的患者,其中男10例,女6例;初装年龄45～67岁,翻修年龄55～78岁,使用时间7～13年。根据术前X线片和术中所见,分为松动/非骨溶解组和松动/骨溶解组,每组各8例,取出假体周围各区的假体-骨间界膜组织。另取6例初装人工全髋关节的骨性关节炎患者作为对照组,其中男2例,女4例;年龄54～68岁,病程9～15年;采用免疫组织化学法检测界膜组织中Caspase-3的表达,末端标记法原位检测细胞凋亡,分析并比较Caspase-3和细胞凋亡的阳性表达和分布,与磨损颗粒的局部聚积和骨溶解程度的关系。结果高分子聚乙烯磨损颗粒局部聚积区的Caspase-3阳性细胞率和细胞凋亡指数明显高于金属磨损颗粒;重度磨损细胞凋亡指数高于轻度磨损,差异有统计学意义(P<0.05);松动/骨溶解组Caspase-3阳性细胞率和细胞凋亡指数明显高于松动/非骨溶解组和对照组,差异有统计学意义(P<0.01)。结论假体周围界膜组织Caspase-3的表达和细胞凋亡具有一定规律性,并与磨损微粒的局部聚积和骨溶解程度密切相关,可能是磨损颗粒造成界面骨重建受阻而溶骨大量发生的关键环节之一;细胞凋亡参与了假体无菌性松动的病理过程,且与Caspase-3信号激活有关。     

Patient sensitivity to polyethylene particles with cemented total hip arthroplasty

To determine whether sensitivity to polyethylene particles varies among patients, we studied 25 patients who had undergone total hip arthroplasty. We used pelvic radiographs to measure annual polyethylene wear and the area of osteolysis. The ratio of the area of osteolysis to the volumetric polyethylene wear was defined as sensitivity index. Adherent cells from peripheral blood were cocultured with polyethylene particles, and the amount of bone-resorptive cytokines was measured. The amount of interleukin-6, but not of interleukin-1beta or tumor necrosis factor-alpha, released from adherent cells in the in vitro experiment correlated with the in vivo sensitivity indices. This technique appears capable of predicting the development of polyethylene-induced osteolysis, allowing surgeons to avoid using polyethylene as the bearing surface in patients at risk for osteolysis.     

Primary total hip arthroplasty with use of the modular S-ROM prosthesis. Four to seven-year clinical and radiographic results

BACKGROUND: A multicenter retrospective study was conducted to determine the clinical and radiographic results of primary total hip arthroplasty with insertion of the S-ROM modular femoral stem without cement in a series of patients who had been followed for four to seven years. Four centers participated in the study, with one contributing surgeon at each center. METHODS: Two hundred and eight consecutive patients who had a total hip arthroplasty with implantation of the S-ROM femoral prosthesis at one of the four centers during the study period were identified. Twenty-nine patients were lost to follow-up or had incomplete radiographic data, and twenty patients died from causes unrelated to the index arthroplasty. The remaining 159 patients formed the basis of this study. Sixteen of these patients had a bilateral procedure, resulting in 175 hips with complete clinical and radiographic data. The average age of the patients at the time of the index operation was fifty-nine years (range, twenty-two to ninety-three years). The duration of clinical follow-up averaged 5.3 years (range, four to 7.8 years), and the duration of radiographic follow-up averaged 4.9 years (range, four to 7.3 years). RESULTS: One patient (0.6 percent) had a failed femoral component, which was evidenced by progressive subsidence and lack of bone ingrowth. In addition, two patients (1 percent) had a revision of the acetabular component. The average Harris hip score increased from 35 points (range, 10 to 76 points) preoperatively to 91 points (range, 52 to 100 points) at the most recent follow-up examination. The radiographic evaluation revealed that 172 hips (98 percent) had stable bone ingrowth, two hips (1 percent) had stable fibrous ingrowth, and one hip (0.6 percent) had unstable fibrous ingrowth. Periprosthetic osteolytic lesions were noted in twelve hips (7 percent). The lesions were observed in the femur in eight hips, in the acetabulum in two hips, and in both the femur and the acetabulum in two hips. All femoral osteolytic lesions were localized within the greater trochanter or the proximal-medial portion of the femoral neck. No osteolytic lesions were evident distal to the stem-sleeve junction. CONCLUSIONS: Use of the modular S-ROM femoral prosthesis yielded excellent intermediate-term outcomes with respect to standard radiographic and clinical criteria. The issue regarding the theoretical increase in the rate of osteolysis due to metal debris generated at the modular femoral stem-sleeve junction was specifically addressed. We found that the rate of osteolysis in this series was not notably higher than that in other series reported in the orthopaedic literature. Although many possible factors may influence the rate of osteolysis in total hip arthroplasty, this finding suggests that the potential increase in osteolysis theoretically associated with this modular femoral implant was not observed at intermediate-term follow-up. Although longer follow-up is warranted so that the potential for osteolysis can be evaluated fully, no osteolytic lesions were evident distal to the stem-sleeve interface at the time of intermediate-term follow-up. This finding suggests that there is a circumferential seal at the modular junction of the stem that prevents the distal egress of wear debris.     

Omnifit cementless total hip arthroplasty. A 10-year average followup.

Seventy-six hips in 67 patients were evaluated an average of 119 months (range, 61-150 months) after total hip arthroplasty with porous coated Omnifit femoral and acetabular components. The patients were young (average age, 45 years), and most were male (67%). Two stems and one cup were revised for aseptic loosening, for aseptic revision rates of 2.6% on the femoral side and 1.3% on the acetabular side. Thigh pain was present in three cases, one of which was activity limiting. Twenty-five (35.7%) hips had evidence of osteolysis confined to proximal Gruen Zone 1 or 7 or to the acetabulum (22 proximal femoral, three both). There were no cases of intramedullary osteolysis in surviving stems. Thirteen (17.1%) hips have undergone reoperation for bone grafting of progressive proximal osteolysis without component revision, at an average 93 months after the total hip arthroplasty. At an average 40 months after reoperation, all stems remain well fixed, and there has been no recurrence of osteolysis of grafted femoral lesions. These results suggest that a circumferentially proximally porous coated femoral component in cementless total hip arthroplasty can provide stable fixation for as long as 12 years after implantation and caseal the canal from distal osteolysis. Serious concerns remain about the incidence of proximal femoral osteolysis.     

Serum interleukin-6 as a marker of periprosthetic infection following total hip and knee arthroplasty

BACKGROUND: The erythrocyte sedimentation rate, the C-reactive protein serum level, and the white blood-cell count are routinely used to diagnose periprosthetic infection. In the present study, the diagnostic accuracy of the interleukin-6 serum level was compared with the accuracy of these standard tests for the evaluation of a group of patients who had had a total hip or total knee arthroplasty and were undergoing a reoperation for the treatment of an infection or another implant-related problem. METHODS: A prospective, case-control study of fifty-eight patients who had had a total hip or knee replacement and were undergoing a reoperation because of an infection (seventeen patients) or another implant-related problem (forty-one patients) was conducted. The serum levels of interleukin-6 and C-reactive protein, the erythrocyte sedimentation rate, and the white blood-cell count were measured. The definitive diagnosis of an infection was determined on the basis of positive histopathological evidence of infection and growth of bacteria on culture of intraoperative specimens. Two-sample Wilcoxon rank-sum (Mann-Whitney) tests were used to determine the presence of a significant difference between patients with and without infection with regard to each laboratory value studied. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of each text were also calculated. RESULTS: The serum interleukin-6 level, erythrocyte sedimentation rate, and C-reactive protein level were significantly higher in patients who had an infection than in those who did not, both when all patients were considered together and when the total hip arthroplasty and total knee arthroplasty groups were considered separately. With the numbers available, there was no significant difference with regard to the white blood-cell count between patients with and without infection. With a normal serum interleukin-6 level defined as <10 pg/mL, the serum interleukin-6 test had a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 1.0, 0.95, 0.89, 1.0, and 97%, respectively. CONCLUSIONS: An elevated serum interleukin-6 level correlated positively with the presence of periprosthetic infection in patients undergoing a reoperation at the site of a total hip or knee arthroplasty. The serum interleukin-6 level is valuable for the diagnosis of periprosthetic infection in patients who have had a total hip or total knee arthroplasty.     

Total hip arthroplasty with a cementless acetabular component and a cemented femoral component in the treatment of Chinese patients with femoral head necrosis

The purpose of this study was to evaluate midterm clinical and radiographic outcomes associated with hybrid total hip arthroplasty in a consecutive series of 86 Chinese patients (93 hips) with osteonecrosis of the femoral head, which revealed that the mean Harris hip score increased from 39 +/- 6.0 points before operation to 90.4 +/- 4.6 points at the latest follow-up. There was pelvic osteolysis in one hip (1%), which required revision, and some small focal areas of femoral osteolysis in 12 hips (13%) were observed. The mean linear wear rate was 0.143 +/- 0.05 mm/y (0.02-0.45 mm/y). No loosening of the components was observed radiographically. The survival rate of the acetabular and femoral components for revision was 98% (95% confidence interval, 0.96-1.0) and 100% (95% confidence interval, 0.95-1.0). Hybrid total hip arthroplasty in patients with osteonecrosis of the femoral head had a satisfactory clinical and radiographic outcome at a minimum 5 years of follow-up. Because polyethylene wear and osteolysis cannot be avoided, the long-term effect should be further studied.     

Total hip arthroplasty in adult patients who had childhood infection of the hip

BACKGROUND: Adult patients with a history of infection of the hip in childhood present a challenge as candidates for total hip arthroplasty because of abnormal bone development, soft-tissue contractures, the possibility of reinfection, and their relative youth. The purpose of this study was to analyze the mid-term results of primary total hip arthroplasty in adult patients who had had infection of the hip in childhood. METHODS: We retrospectively analyzed 170 total hip arthroplasties that had been performed between 1983 and 1996 in patients who had had infection of the hip during childhood. Forty-seven hips had cemented or hybrid total hip replacements, and 123 hips had cementless total hip replacements. The age of the patients at the time that the infection was contracted was an average of 7.3 years (range, one to eleven years). The average age of the patients at the time of the index total hip arthroplasty was 41.9 years in the cemented or hybrid group and 42.7 years in the cementless group. The interval between active infection and arthroplasty was 34.9 years in the cemented or hybrid group and 31.9 years in the cementless group. All but two hips (one patient) had a quiescent period of infection of more than ten years. The average duration of follow-up was 9.8 years (range, seven to seventeen years) in the cemented or hybrid group and 10.8 years (range, seven to seventeen years) in the cementless group. RESULTS: All hips with a quiescent period of more than ten years had no recurrence of infection. The remaining two hips in one patient with a quiescent period of seven years had recurrence of the infection. The mean Harris hip scores improved from 50 points preoperatively to 85 points at the latest follow-up examination in the cemented or hybrid group and from 50 points preoperatively to 89 points at the latest follow-up examination in the cementless group. Eight (17%) of forty-seven hips with cemented or hybrid fixation and eighteen (15%) of 123 hips with cementless fixation had revision of both components because of aseptic loosening and/or osteolysis. The mean rate of linear wear of the polyethylene was 0.25 mm per year in the cemented or hybrid group and 0.29 mm per year in the cementless group. The prevalence of osteolysis was 53% (twenty-five of forty-seven hips) in the cemented or hybrid group and 59% (seventy-two of 123 hips) in the cementless group. CONCLUSIONS: There was no recurrence of infection after total hip arthroplasty in the patients with a quiescent period of infection of more than ten years. These young, active patients with technically difficult arthroplasties were at considerable risk for aseptic loosening. The prevalence of polyethylene wear and osteolysis was attributable to the less than optimal prosthetic designs and materials used during the time-period of this study.     

Fixation and osteolysis in plasma-sprayed hemispherical cups with hybrid total hip arthroplasty

The optimal surface finish on cementless total hip arthroplasty is still a matter of debate. 145 hips in 130 patients with hybrid total hip arthroplasty using a hemispherical, titanium plasma-sprayed cup were followed for an average of 8.5 years. The average age was 63 years, and the average weight was 165 lb. Three hips were revised for polyethylene wear and synovitis/osteolysis. In all 3 cases, the acetabular component remained well fixed. Radiographically, 5 hips had femoral osteolysis, and 5 sockets had osteolysis in zone 2, with 4 in zone 1. There were no cases of progressive lucent lines, and no acetabular components were revised. Plasma-sprayed acetabular components remain durable up to 12 years. Moreover, in cases with wear particle overload and osteolysis, fixation was maintained at revision surgery.     

Osteolysis in cemented versus cementless acetabular components

A prospective, randomized, double-blind, clinical trial comparing cemented with cementless total hip arthroplasty was performed to compare the prevalence and pattern of acetabular osteolysis. Both groups were similar before surgery. Acetabular components were metal-backed, titanium implants. Twenty-eight-millimeter modular femoral heads with titanium femoral stems were used. At a minimum 2-year and mean 4-year follow-up period (range, 2–6 years), 224 patients had clinical and radiographic data available. There was no significant difference in the prevalence of acetabular osteolysis between cemented (5%) and cementless (9%) fixation. With or without cement, the use of a titanium femoral head led to osteolysis within a relatively short period after surgery in almost all of the cases, although this was not significant. The pattern of acetabular osteolysis was different. Progressive osteolysis occurred predominantly in acetabular zone 1 in the cemented group and zone 2 in the cementless group. Cementless fixation of acetabular components has been advocated in an attempt to minimize osteolysis that may occur in cemented total hip arthroplasty. This study found no difference in the prevalence of acetabular osteolysis between the two groups.     

Revision Total Hip Arthroplasty Using an Alumina-On-Alumina Bearing Surface in Patients With Osteolysis

We evaluated the outcomes of 64 consecutive revision total hip arthroplasties with an alumina-on-alumina bearing surface in 61 patients with osteolysis. No implants had been rerevised nor was osteolysis detected at a mean of 9.8 years (range, 7.0-13.1 years) postoperatively. There was 1 case of stem loosening but no cup loosening or alumina bearing fractures. Two surgical procedures were performed for an infection in 1 patient. Three dislocations occurred in 3 hips; all were treated with closed reduction and abduction bracing for 3 months. No further dislocations occurred. With any reoperation or radiographic evidence of osteolysis or loosening as the end point, the 7-year survival rate was 96.9% (95% confidence interval, 90.8%-100%). The alumina-on-alumina bearing surfaces used for revision total hip arthroplasty in patients with osteolysis were found to produce encouraging clinical results and implant survival rates at a minimum of 7 years postoperatively.     

Polyethylene wear and calcar osteolysis

We have examined retrospectively the correlation between linear wear of the polyethylene socket and calcar height loss (osteolysis) in 266 patients with 410 total hip arthroplasties who were followed up for a minimum of 10 years. A positive correlation existed between wear and osteolysis. The correlation was stronger in patients with osteoarthrosis. Simultaneous bilateral hip arthroplasty showed no difference in the relationship between polyethylene wear and calcar height loss when comparing the right and left hip. There was poor correlation between calcar height loss and wear in patients with rheumatoid arthritis. Our findings support the theory that femoral osteolysis in the total hip arthroplasty is related to the amount of liberated particles generated by the wear of components. The poor correlation found in cases with rheumatoid arthritis could be related to suppression of the immune response in these patients.     

Pregnancy after total hip arthroplasty.

BACKGROUND: Younger patients are having total hip arthroplasty now, and a woman who has had such a procedure may want to become pregnant. The purposes of this study were to report on a series of women who had completed a pregnancy after a total hip arthroplasty and to determine if pregnancy affects the function and longevity of the prosthesis. METHODS: Five women, with a total of seven uncemented total hip replacements, had six successful pregnancies. The mean age at the arthroplasty was twenty-nine years (range, twenty-two to thirty-eight years), and the mean time from the hip arthroplasty to the pregnancy was 2.5 years (range, one to seven years). These patients (Group A) were compared with a matched group of five women with a total of eight uncemented total hip prostheses (Group B) who had not completed a pregnancy. The mean follow-up time was eight years (range, two to thirteen years) for Group A and seven years (range, two to twelve years) for Group B. Patients were clinically evaluated with the Harris hip score. Radiographs were evaluated for component fixation and osteolysis. RESULTS: The five women completed a total of six successful pregnancies. One patient, with a bilateral total hip arthroplasty, had two successful pregnancies, 2.5 years apart. Three children were delivered vaginally (with the mother in the lithotomy position) and three, by cesarean section. There were no complications related to the total hip arthroplasty after delivery. The mean weight gain during the pregnancy was 13 kg (range, 8 to 14.2 kg). In Group A, the mean Harris hip score was 94 points prior to the pregnancy and 97 points at the time of the most recent follow-up. In group B, the mean Harris hip score was 91 points at one to two years after the arthroplasty and it was unchanged at the time of the most recent follow-up. There were six excellent results and one good result of the hip arthroplasty in Group A and five excellent and three good results in Group B. The mean total arc of hip motion was 217 degrees in Group A before the pregnancy and 241 degrees at the time of the most recent follow-up. The mean total arc of hip motion was 193 degrees in Group B at one to two years postoperatively and 190 degrees at the time of the most recent follow-up. The difference in the total arc of hip motion between the two groups at the latest follow-up evaluation was significant (p = 0.025). There were no reoperations in either group. Radiographs showed osteolysis of the femur in three hips in Group A and three hips in Group B. CONCLUSIONS: It appears that successful pregnancy and normal vaginal delivery can occur safely after total hip arthroplasty. The overall result, function, and radiographic appearance after the total hip arthroplasty was not adversely affected by pregnancy in this small group of patients.     

Third-generation ceramic-on-ceramic total hip arthroplasty in patients younger than 30 years with osteonecrosis of femoral head

The purpose of this study was to evaluate the functional and radiographic results of patients younger than 30 years who underwent cementless third-generation ceramic-on-ceramic total hip arthroplasty for osteonecrosis of the femoral head. Forty-one patients (56 hips) with a minimum follow-up of 6 years were included. In all cases, third-generation ceramic-on-ceramic articulation was used. Average Harris Hip Scores improved from 52.9 preoperatively to 98.2, and Western Ontario and McMaster Universities Osteoarthritis Index score, from 95.2 to 25.2. Thirty-nine patients returned to their normal occupations. No aseptic loosening or osteolysis was observed. Total hip arthroplasty performed using third-generation ceramic-on-ceramic bearings for osteonecrosis of femoral head was found to provide satisfactory clinical and radiologic results, especially in active, young patients.     

Radiographic and clinical analysis of cementless acetabular fixation in total hip arthroplasty

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Early osteolysis following second-generation metal-on-metal hip replacement

BACKGROUND: Total hip arthroplasty with use of metal-on-metal bearings has been reintroduced as an alternative to the use of metal-on-polyethylene bearings because of theoretical advantages such as reduced wear and a lower prevalence of osteolysis. However, we observed early osteolysis in a cohort of patients who had been managed with second-generation metal-on-metal hip replacements and investigated the possible etiologic role of metal hypersensitivity. METHODS: We retrospectively analyzed 165 patients (169 hips) who had undergone primary cementless total hip replacement with a contemporary metal-on-metal total hip design between 2000 and 2002. After a minimum duration of follow-up of twenty-four months, nine patients (ten hips) had an osteolytic lesion localized to the greater trochanter. Skin-patch tests for hypersensitivity to metals were performed on the nine patients and on nine randomly selected patients with total hip replacements who did not have osteolytic changes and who were matched to the study cohort for age and gender. Microbiological cultures, histopathologic examinations, and immunohistochemical analysis were performed on samples of periprosthetic tissue that were collected during revision arthroplasty on two hips with early osteolysis. RESULTS: The patients with early osteolysis had a significantly higher rate of hypersensitivity reaction to cobalt compared with controls (p = 0.031). The retrieved periprosthetic tissues showed no evidence of metallic staining, but histologic analysis revealed a perivascular accumulation of CD3-positive T-cells and CD68-positive macrophages and an absence of both particle-laden macrophages and polymorphonuclear cells. Immunohistochemical analysis demonstrated that bone-resorbing cytokines such as IL-1beta and TNF-alpha were produced mainly by infiltrating lymphocytes and activated macrophages. CONCLUSIONS: These findings raise the possibility that early osteolysis in patients with this second-generation metal-on-metal hip replacement is associated with abnormalities consistent with delayed-type hypersensitivity to metal. A prospective study in which a large group of patients is evaluated with multiple diagnostic methods is needed in order to establish whether there is a causal relationship between metal hypersensitivity and osteolysis.     

Bipolar versus total hip arthroplasty for hip osteonecrosis in the same patient

The authors studied 28 patients with bilateral avascular necrosis of the femoral head who were treated with a cementless bipolar endoprosthesis in one hip and cementless total hip arthroplasty in the other. All the hips selected for bipolar endoprostheses were classified as having avascular necrosis of the femoral head Ficat Stage III, and all the hips selected for total hip arthroplasty were classified as having Ficat Stage IV avascular necrosis. After a midterm followup of an average of 6.4 years (range, 4-12 years), 24 of 28 hips that received bipolar endoprostheses were considered satisfactory, whereas 23 of 28 hips in which an arthroplasty was done were considered satisfactory. After a followup of more than 6 years, the cartilaginous space of the acetabulum could be preserved in 25 hips (89.3%) that received a bipolar endoprosthesis. There were no statistical differences in both groups in terms of clinical result, thigh pain, groin pain, osteolysis, dislocation, and revision rate. Total hip arthroplasty is not the preferred treatment for all patients with hip osteonecrosis. In young patients with Ficat Stage III osteonecrosis with Grade 0 or Grade I cartilage, the use of a cementless bipolar endoprosthesis with a bone ingrowth stem may be considered as an alternative to total hip arthroplasty.