Cementless total hip arthroplasty with a metal-on-metal bearing in patients younger than 50 years

Total hip arthroplasty (THA) longevity is the primary concern in young patients. Metal-on-metal articulations were reintroduced to reduce polyethylene particle-induced osteolysis and improve survivorship; to date, based on issued reports, this strategy appears to have been successful. In this study, the authors investigated metal-on-metal articulation survivorship and osteolysis incidence in young patients (19-50 years old at index operations) and retrospectively reviewed cementless metal-on-metal THAs in 70 patients (78 hips) with a mean follow-up of 12.4 years. Metasul articulation was used with the Wagner acetabular component in all. Survivorship with revision for any cause was 98.7% (95% confidence interval, 98%-100%), and survivorship due to the development of osteolysis for any lesion was 97.5% (95% confidence interval, 95%-99%). Mean Harris hip score improved from 51 to 95 points at final follow-up. The findings of this study indicate that outcomes of cementless THA with a metal-on-metal bearing in young patients are satisfactory. However, longer-term studies in larger cohorts are required to determine whether metal-on-metal articulations are really a favorable option in young patients.     

Midterm results of Metasul metal-on-metal total hip arthroplasty

We assessed 106 total hip arthroplasties performed with a new metal-on-metal hip system; the patients were monitored for at least 5 years. The average Harris Hip Score of the patients was 39.5 points before surgery and 87.8 points at final follow-up evaluation. Radiographically, the acetabular component was stable in 103 hips and possibly unstable in 3 hips. The femoral component was bone ingrown in 97 hips and stable and fibrous in 9. After surgery, 6 hips dislocated. The polyethylene liner dissociated in one patient. No patient exhibited clear signs of loosening, migration, or osteolysis. Distal femoral cortical hypertrophy was seen in 35.8% of the cases. Survival at the mean follow-up point (6.4 years) was 99.1%. There was no significant difference in serum chromium concentration between metal-on-metal bearings and polyethylene-on-metal bearings (control subjects). This study found that metal-on-metal total hip arthroplasty produces excellent midterm results.     

Fixation and osteolysis with Metasul metal-on-metal articulation

The purpose of this study was to report the prevalence of osteolysis and loss of fixation using Metasul metal-on-metal articulation couples. Ninety-two patients with 96 hips with Metasul articulation couples were followed for 5 to 11 years. By patient self-assessment, 89 (93%) patients scored themselves as good or excellent. The occurrence of osteolysis and the grading of fixation were obtained from plain radiographs. The clinical evaluation for these patients was performed by patient self-assessment. With the use of plain radiographs, there was no osteolysis observed in these 96 hips other than calcar resorption (6 hips [6.3%]). All components were fixed, except for 1 loose cup that was revised, and this level of fixation allowed a fair evaluation for osteolysis around well-functioning implants.     

Metasul非骨水泥金属对金属全髋关节置换随访报告

[目的]探讨Metasul非骨水泥金属对金属全髋关节假体在人工全髋关节置换术中的应用效果.[方法]对本科于2003年8月-2005年12月行Metasul非骨水泥金属对金属人工全髋关节置换术25例(30髋)患者进行了随访.包括临床评估和放射学评估,并检测血铬浓度和肾功能情况.[结果]23例28髋获得随访,平均随访3.6年(2.5～4.8年).患者的平均Harris评分由术前的49.5分提高到末次随访时的93.4分.3髋(11.5%)形成透亮带;1髋股骨形成局灶性骨溶解.1例术中坐骨神经受损,2.5年后除趾背伸肌力较弱外其他均完全恢复.1例糖尿病患者血糖未控制理想,术后4年发生假体周围感染但X线检查未见松动迹象.无一术后发生脱位、股骨骨折等并发症.末次随访时平均血铬浓度为0.82 μg/L(0.020～0.140 μg/L),较正常参考值(0.007、0.109)无明显升高,未发现因血铬浓度升高导致的肾功能损害和癌症、白血病等恶性疾病.[结论]Metasul非骨水泥金属对金属全髋关节假体在人工全髋关节置换术中的效果令人满意,但有必要做进一步随访,以了解与金属对金属关节置换有关的任何不良反应.     

Disappointing short-term results with the DePuy ASR XL metal-on-metal total hip arthroplasty

Outcomes of ultralarge-diameter femoral heads used in metal-on-metal (MOM) total hip arthroplasty (THA) are relatively unknown. This study reports on early failures of the ASR XL (Depuy, Warsaw, Ind) and assesses whether a correlation with cup positioning exists. A retrospective review of 70 consecutive MOM THAs with ultralarge-diameter femoral head and monoblock acetabular component was conducted. Minimum follow-up was 24 months. Of 70 THAs, 12 (17.1%) required revision within 3 years for pain (7), loosening (3), and squeaking (2). Three additional THAs noted squeaking, 2 noted grinding, and 3 additional hips had persistent pain. In total, 20 (28.6%) of 70 demonstrated implant dysfunction. Acetabular components for all symptomatic hips were in acceptable range of cup abduction and anteversion. The failures noted with this design do not correlate to cup placement. The high rate of implant dysfunction at early follow-up suggests serious concerns with the concept of MOM THA with an ultralarge-diameter femoral head paired with a monoblock acetabular cup.     

Serum chromium levels before and after revision surgery for loosened metal-on-metal total hip arthroplasty

We investigated the changes of serum chromium levels before and after revision surgery in 10 patients (1 male and 9 females) who underwent exchange of a metal-on-metal articulation for a metal-on-polyethylene component because of aseptic loosening of a metal-on-metal total hip prosthesis. Of the 10 patients, 2 had bilateral metal-on-metal total hip arthroplasty. In the 8 patients who had no residual metal articulation, the mean serum chromium levels before and after revision surgery were 2.53 microg/L and 0.46 microg/L, respectively. In the 2 patients who still had a metal articulation on the contralateral side, the mean serum chromium levels before and after revision surgery were 2.85 microg/L and 1.90 microg/L, respectively. Moderate serum chromium levels in patients with metal-on-metal total hip arthroplasty show a decrease after removal of the metal-on-metal articulation.     

Cystic lesion of the groin due to metallosis: a rare long-term complication of metal-on-metal total hip arthroplasty

We present 2 patients with swelling of the groin after metal-on-metal total hip arthroplasty without radiological signs of component loosening. Magnetic resonance imaging in both patients showed a round intrapelvic lesion ventral to the femoral head. During surgery, we found cystic structures filled with fluid and necrotic masses. After resection of the cyst, the metal head and insert were replaced by a new ceramic head and a polyethylene liner. Although 2 different kinds of alloy were used (Sikomet, low carbon content; Metasul, high carbon content), histopathological analysis in both cases showed typical morphological signs of a hypersensitively determined inflammation. Despite the distinct soft tissue reaction, bony component integration was unaffected. In our opinion, open resection of the cystic lesion and changing of the metal-on-metal articulation is the treatment of choice.     

Failure of larger-diameter metal-on-metal total hip arthroplasty resulting from anterior iliopsoas impingement

Anterior iliopsoas impingement is a recognized cause of persistent groin pain after total hip arthroplasty. We report 3 patients with failed total hip arthroplasties resulting from anterior iliopsoas and capsular impingement secondary to a metal femoral ball with a diameter larger than the native femoral head. All patients had the same implant design. Resolution of symptoms occurred in all patients after revision surgery. To our knowledge, this is the first report of this potential failure mechanism with these large-diameter implant designs and should be considered in the appropriate clinical scenario.     

Minimum 5-year results of modular metal-on-metal total hip arthroplasty

This study reports minimum 5-year results of 95 hips implanted with a Pinnacle (DePuy, Warsaw, Ind) modular metal-on-metal acetabular prosthesis. Clinical scores such as the Harris Hip and Western Ontario and McMaster Universities Arthritis Index revealed excellent clinical outcomes at mean 6-year follow-up. With the use of large-diameter femoral heads, dislocation was rare, occurring in only 1 hip. Moreover, no acetabular and only 3 femoral osteolytic lesions were detected. Kaplan-Meier survivorship at 7 years after arthroplasty was 97.8% for the total hip arthroplasty construct and 100% for the acetabular shell. No unexplained pain or other complication attributable to wear debris or the metal-on-metal articulation was observed. These findings indicate that total hip arthroplasty with this specific modular metal-on-metal bearing performed well in a high-demand population at midterm follow-up.     

Primary Hip Arthroplasty With 28-mm Metasul Articulation

This follow-up study reports on 69 patients at mean 13 years with total hip arthroplasty using 28-mm Metasul (Zimmer, Winterthur, Switzerland) metal-on-metal articulation. These results are not transferable to large-diameter head metal-on-metal articulations. Four new revisions, 3 for disassociation of the liner and 1 for mechanical loosening of the acetabulum, occurred since the previous report of mean 7.3 years. The prevalent cause of late revision is disassociation, which suggests a high frictional torque or impingement in these articulation surfaces. No revision was done for osteolysis. Overall, of the original 127 hips, 116 (91%) were known to have maintained their original components.     

Serum metal ion concentrations after unilateral vs bilateral large-head metal-on-metal primary total hip arthroplasty

It is unknown if the presence of bilateral well-functioning large-head metal-on-metal (MOM) total hip arthroplasties (THAs) leads to higher serum metal ion concentrations than unilateral MOM THA. Elevated levels (chromium, 17 μg/L; cobalt, 19 μg/L) have been associated with poorly functioning MOM THA with metallosis. Fourteen patients having undergone bilateral and 25 patients having undergone unilateral large-head primary MOM THA were compared. Harris Hip Scores, University of California Los Angeles activity scores, radiographs, serum creatinine, and serum cobalt and chromium levels were obtained. Only cobalt ion levels were significantly higher in the bilateral group than in the unilateral group (1.8 μg/L vs 1.0 μg/L, P = .029). Comparatively, this magnitude is clinically rather low because ion levels did not approach those associated with metallosis in either group. We conclude that although patients with well-functioning bilateral MOM THA may have slightly higher cobalt levels, neither cobalt nor chromium levels approach those seen in poorly functioning MOM THA with metallosis.     

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.     

Results of total hip and total knee arthroplasties in patients with synovial chondromatosis

This retrospective analysis examines the outcome of total joint arthroplasty for severe arthritis in patients with synovial chondromatosis. All 11 patients treated with total hip arthroplasty (n = 7) or total knee arthroplasty (n = 4) returned for follow-up at a mean of 10.8 years after surgery. Pain and functional scores improved significantly in all patients. Knee range of motion improved in all patients. Synovial chondromatosis recurred in 1 knee (25%) and 1 hip (14%). Total joint arthroplasty is a valuable treatment option for these patients with predictable improvement in pain and function. Knee range of motion is likely to improve but may be less than expected for primary total knee arthroplasty. Patients remain at risk for recurrence.     

Cementless Acetabular Socket Revisions Using Metasul Metal-on-Metal Bearings

Thirty-four hips were treated with cementless acetabular socket revisions using a metal-on-metal bearing. The causes of revision were aseptic loosening in 33 hips and septic loosening in 1 hip. Revisions were performed for acetabular sockets in 28 hips and for acetabular sockets and femoral stems in 6 hips. Mean follow-up duration was 6.2 years (range, 4.0-9.1 years), and mean Harris Hip Scores improved from 56 to 92 points. No hip required further revision for aseptic loosening. Focal femoral osteolysis newly developed in zone I in 1 hip, which was treated by curettage and bone grafting. The authors suggest that second-generation metal-on-metal bearings in cementless acetabular socket revisions can achieve good medium-term clinical and radiographic results.     

Femoral revision in hip resurfacing compared with large-bearing metal-on-metal hip arthroplasty

It has been suggested that revision of the femoral component of hip resurfacing after femoral failure would be straightforward and have an outcome comparable to primary total hip arthroplasty (THA). We have compared the outcome of femoral side-only revision resurfacings to the results of primary modular large-bearing metal-on-metal THA. Fourteen consecutive patients underwent revision surgery of the failed femoral component, to a cemented tapered stem (CPT, Zimmer, Warsaw, Indiana) with a large modular metal head (Smith and Nephew Orthopaedics Ltd, Memphis, Tennessee, or Adept, Finsbury Orthopaedics, Surrey, England). The acetabular component was found to be well fixed, well orientated, and was left in situ. The 14 matched patients in the primary THA group received the same components. At a mean follow-up of 49 months (range, 30-60 months), clinical outcome measured using the Oxford and Harris Hip Scores showed no significant difference (P = .11, P = .45, respectively). Operative time and blood loss were comparable for both groups. We conclude that revision of the failed femoral resurfacing component gives excellent results.     

Gait analysis of patients with resurfacing hip arthroplasty compared with hip osteoarthritis and standard total hip arthroplasty

Patients with standard total hip arthroplasties may have reduced hip abduction and extension moments when compared with normal nonosteoarthritic hips. In comparison, patients after resurfacing total hip arthroplasty appear to have a near-normal gait. The authors evaluated temporal-spatial parameters, hip kinematics, and kinetics in hip resurfacing patients compared with patients with unilateral osteoarthritic hips and unilateral standard total hip arthroplasties. Patients with resurfacing walked faster (average 1.26 m/s) and were comparable with normals. There were no significant differences in hip abductor and extensor moments of patients with resurfacing compared with patients in the standard hip arthroplasty group. This study showed more normal hip kinematics and functionality in resurfacing hip arthroplasty, which may be due to the large femoral head.     

Cementless alumina-on-alumina total hip arthroplasty in patients younger than 50 years: a 5-year minimum follow-up study

Sixty-seven patients (78 hips) who were younger than 50 years underwent cementless total hip arthroplasty using a porous-coated acetabular cup, an alumina liner, a 28-mm alumina head, and a proximally porous-coated femoral stem. One patient (1 hip) died and 2 patients (3 hips) were lost to follow-up. The remaining 64 patients (74 hips) were followed for 5 to 6 years. Their mean age at the index operation was 37 years. The mean Harris hip score was 94 points at the time of final follow-up. Four patients (4 hips) had mild thigh pain. All acetabular and femoral components were bone-ingrown, and neither pelvic nor femoral osteolysis was identified. No fracture of the ceramic liner or head was identified. Wear of the ceramic components was undetectable in 27 hips in which measurement was possible.     

Cementless two-stage exchange arthroplasty for infection after total hip arthroplasty

We retrospectively reviewed all patients at one center with an infected total hip arthroplasty treated with 2-stage revision using cementless components for the second stage and the PROSTALAC articulated spacer at the first stage. Twenty-nine patients were reviewed and followed for at least 2 years postoperatively. An isolated Staphylococcus species was cultured in 76% (22/29) of patients. Three (10.3%) of 29 patients had recurrent infection at the site of the prosthesis. One of the 3 patients ultimately underwent a Girdlestone arthroplasty. Another patient was managed with irrigation and debridement, whereas the final patient was treated with intravenous antibiotics alone. Treatment of infection at the site of a hip arthroplasty with 2-stage revision using cementless components and an articulated spacer yields recurrence rates similar to revisions where at least one of the components at the second stage is fixed with antibiotic-loaded cement.     

Gait symmetry: a comparison of hip resurfacing and jumbo head total hip arthroplasty patients

Proponents of large femoral head total hip arthroplasty (THA) and hip resurfacing arthroplasty (HRA) have touted the potential for restoration of more normal hip kinematics. This study examined 20 patients (10 THA and 10 HRA patients) approximately 18 months after surgery. Subjects were evaluated at a self-selected pace, while bilateral spatial-temporal gait variables, hip flexion/extension kinematics, and ground reaction forces were collected. For both groups, swing time was increased on the surgical side, whereas peak hip flexion, peak extension, and flexion at heel strike were decreased. Peak hip extension and peak vertical ground reaction forces were decreased in THA subjects compared with HRA subjects. After a large-diameter THA or HRA, subjects do not display symmetric gait approximately 18 months postoperatively. Total hip arthroplasty subjects demonstrated restricted hip extension and reduced limb loading when compared with HRA subjects.     

The agreement and repeatability of computer-based wear measurement of total hip arthroplasties

We assessed the agreement and repeatability of a software package for wear measurement in 19 total hip arthroplasties followed up for 4 to 8 years. Three observers with different levels of expertise (a hip surgeon [O1], a fellow [O2], and a medical student who is a research assistant of the laboratory in which the software was developed [O3]) determined the 2-dimensional wear and wear direction with the Hip Suite software (University of Chicago, Chicago, Ill). For intraobserver and interobserver comparisons, we used intraclass correlation coefficient (ICC) and repeatability. The intraobserver ICC for wear and wear direction was 0.83 and 0.78 for O1, 0.54 and 0.48 for O2, and 0.81 and 0.89 for 03. The interobserver ICCs were 0.43 (range, 0.07-0.87) for wear and 0.8 (range, 0.71-0.86) for wear direction. Computerized wear measurements have substantial intraobserver and interobserver variability, especially when performed by surgeons without extensive experience in the use of the software, a finding which questions its precision and validity.