BACKGROUND Isolated acetabular revisions using standard cups are at risk of dislocation. The introduction of a nonconstrained dual-mobility cup was designed to improve prosthetic stability without increasing loosening rates, but it is unclear whether the risk of dislocation is reduced. QUESTIONS/PURPOSES We therefore determined:(1) if the rate of dislocation in isolated acetabular revisions is lower with a dual-mobility cup,(2) implant survival,(3) patient function, and (4) radiographic incidence of migration, loosening, and osteolysis. METHODS We prospectively followed 33 selected patients who underwent isolated acetabular revisions with a minimum of 2 years' followup (mean, 3 years; range, 2-5 years). In 24 patients a stainless steel dual-mobility cup was cemented into an antiprotrusio cage, whereas in nine we used a hyaluronan dual-mobility revision cup with a foramen hook and superior and posterior flanges screw fixations. We determined Harris hip (HHS) and WOMAC scores and examined radiographs for migration, loosening, and osteolysis. RESULTS There were no dislocations. Survivorship rates of the femoral and acetabular components were 97% at 5 years; the rerevision rate for any reason was 3%. At last followup, the mean HHS increased from 48 points preoperatively to 86 points. No patients had progressive osteolysis, component migration, or loosening on radiographs. CONCLUSION In this select group of isolated acetabular revisions, our data suggest the use of a dual-mobility cup reduced the risk of dislocation without increasing loosening from 2 to 5 years. LEVEL OF EVIDENCE Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Radiographs of the hand, hip and knee were screened for evidence of osteoarthritis (OA). Specific sites selected for screening on the postero-anterior radiographs of the hand included the base of the thumb with distal and proximal interphalangeal joints; these regions were examined for formation of marginal osteophytes, joint space narrowing and subchondral lucency. Sites selected from antero-posterior radiographs of the hip included the acetabular and femoral portions of the joint; these regions were examined for joint space narrowing, subchondral lucency, marginal osteophytes and subchondral sclerosis. Sites selected from antero-posterior weight-bearing radiographs of the knee included distal femora and proximal tibiae including the medial and lateral compartments; these regions were examined for joint space narrowing, marginal osteophytes and subchondral sclerosis. Sites selected from axial views of the patellofemoral joint examined the medial and lateral portions; these regions were examined for joint space narrowing, osteophytes, subluxations and subchondral sclerosis. A set of photographic prints was made from the collection of radiographs. These specific features of OA were graded on each print and a subset of prints was selected that best demonstrated the spectrum of severity for each feature of OA. This resultant atlas is offered as an updated guide to standardize interpretation of radiographs prior to and during clinical trials.

Of the first 300 consecutive patients who had a Charnley total hip replacement at the Mayo Clinic during the years 1960 to 1970, 207 (231 hips) were re-evaluated ten years postoperative by questionnaire and roentgenograms. Forty-three of these were also evaluated by personal examination. Roentgenographic loosening of the acetabular component was determined using the criterion of a complete radiolucent line more than one millimeter in width at the bone-cement interface or any migration or tilting of the component. For the femoral component, the criterion for loosening was a radiolucent line more than one millimeter wide at either the bone-cement or the cement-prosthesis interface, or any change in the position of the component. As previously reported, the incidence of loose components at five years was 6.5 per cent for the acetabular component and 24 per cent for the femoral component. At ten years the incidence of loosening had increased to 11.3 per cent for the acetabular component and 29.9 per cent for the femoral component. Therefore, between five and ten years postoperatively the rate of femoral loosening decreased, while the rate of acetabular loosening remained about the same. The overall-revision rate for loosening of total hip components increased from 3 per cent at five years to 7.4 per cent at ten years. Acetabular wear was not a significant problem. Resorption of the medial femoral cortex near the calcar was generally non-progressive and was not significantly related to loosening. two modes of loosening are suggested, the more common being cracking of the cement mantle due to circumferential (hoop) stresses within the cement. This series probably represents a so-called worst-case experience, since changes in design and materials as well as the improvements in surgical technique that have evolved over the past decade should provide significantly better long-term fixation.

One hundred consecutive Müller curved-stem total hip replacements were reviewed ten years after operation. Twenty patients with twenty-two arthroplasties had died within the ten-year period without having a revision, and twenty-five arthroplasties had been revised for various reasons. Of the remaining fifty-three arthroplasties, thirty-five were classified as good or excellent, with Harris hip scores of 80 points or higher, and eighteen were classified as poor or fair, with scores lower than 80 points. Follow-up radiographs, made for all but six of the fifty-three hips at ten years, showed a 23 per cent incidence of migration of the acetabular component and a 28 per cent incidence of migration of the femoral component. In addition, there was a 15 per cent incidence of bone resorption in the proximal end of the femur without migration of the femoral component and a 4 per cent incidence of osteolytic defects about the femoral component, also without migration. Combining the radiographically loose replacement (migration) with the clinically loose ones (revised), the over-all incidence of aseptic loosening was 29 per cent for the acetabular component and 40 per cent for the femoral component. There was a positive correlation between the incidence of loosening of the femoral component and younger age, heavier weight, male sex, unilateral hip disease, a wide femoral canal, and varus position of the femoral component, whereas the incidence of loosening of the acetabular component was increased only in association with older age. The rate of loosening of the femoral component appeared to be higher during the early follow-up period and to decrease with time, while the rate of loosening of the acetabular component appeared to be lower during the early follow-up period but to increase with time.

In a series of 200 Charnley low friction arthroplasties revised for various reasons, the preoperative anteroposterior roentgenograms were categorized in terms of demarcation at the bone-cement interface of the socket and compared with the operative findings of movement at the bone-cement junction. All sockets showing no demarcation were found to be fixed soundly. Seven percent of the sockets showing demarcation of the outer one-third only were loose, and when two-thirds of the sockets were demarcated, 71% were loose. Ninety-four percent of the sockets with complete demarcation and all sockets that had migrated were found to be loose at revision. There is a definite correlation between roentgenographic demarcation and socket loosening. The more extensive the demarcation, the more likely it is that the socket is loose. Radiographic demarcation of the cemented socket is a prognostic sign for eventual failure.

To assess the effect of improved methods of femoral cementing on the loosening rates in young patients, we reviewed 50 'second-generation' cemented hip arthroplasties in 44 patients aged 50 years or less. The femoral stems were all collared and rectangular in cross-section with rounded corners. The cement was delivered by a gun into a medullary canal occluded distally with a cement plug. A clinical and radiographic review was undertaken at an average of 12 years (10 to 14.8) and no patient was lost to follow-up. No femoral component was revised for aseptic loosening, and only one stem was definitely loose by radiographic criteria. By contrast, 11 patients had undergone revision for symptomatic aseptic loosening of the acetabular component and 11 more had radiographic signs of acetabular loosening.

Massive localized osteolysis around artificial joints has been seen more frequently in the past few years. It is still not generally accepted that ultra-high molecular weight polyethylene (UHMWPE) wear particles can induce massive bone resorption, even distant from the joint. This article describes a series of eight soft-top prostheses with large UHMWPE ball heads that contributed to the erosion of surrounding bone. Roentgenographically, all of the cases showed a marked loss of proximal cortical bone, more or less combined with osteolysis, which was distal to the femoral shaft and deep into the acetabulum. In two cases, remodeling and resorption transformed the bone into a tumorlike appearance. Tissue samples from areas of osteolysis as well as from the joint capsule were taken at revision surgery, processed for histology, examined microscopically, and evaluated semiquantitatively. The retrieved devices were also carefully inspected. Large amounts of UHMWPE wear debris were found not only in the joint capsule but also in layers of granulomatous tissue from the acetabulum and femur, whereas metal particles and fragmented polymethylmethacrylate were either completely absent or occurred only in very small amounts. The results of this study demonstrate that UHMWPE wear products alone can cause massive osteolysis by triggering foreign-body granuloma formation at the bone-cement interface; the bone cement may remain fixed in areas beyond the osteolytic transformation.

We evaluated the results of 330 total hip arthroplasties that were performed with use of the Charnley prosthesis and cement in 262 patients by the senior one of us between July 1970 and April 1972. All hips had been thoroughly assessed preoperatively to document the patient's functional level. All patients had been disabled because of pain in the hip or a fracture of the hip, and 212 patients (81 per cent) had used walking aids. At a minimum of twenty years after the index operation, eighty-three patients (ninety-eight hips) were still living, 174 patients (224 hips) had died, and five patients (eight hips) had been lost to follow-up. The outcome of the arthroplasty was determined for all except the five latter patients. Thus, the outcome of 322 (98 per cent) of the 330 arthroplasties was known at the latest follow-up evaluation. Radiographs were available for sixty-three of the eighty-three patients (seventy-six [78 per cent] of the ninety-eight hips) who were alive for the entire follow-up period. Of the ninety-eight hips in the living patients, eighty-three (85 per cent) caused no pain, fourteen (14 per cent) caused mild pain, and one (1 per cent) caused moderate pain. Fifty-two hips (53 per cent) were in patients who did not use walking aids, and only seven (7 per cent) were in patients who used support for walking because of the hip. At the minimum twenty-year follow-up, thirty-two (10 per cent) of the 322 hips that had been followed had been revised: eight (2 per cent), because of loosening with infection; twenty-one (7 per cent), because of aseptic loosening; and three (1 per cent), because of dislocation. Of the ninety-eight hips of the patients who were still alive, fifteen (15 per cent) had been revised: three (3 per cent), because of loosening with infection; eleven (11 per cent), because of aseptic loosening; and one (1 per cent), because of dislocation. The rate of revision due to aseptic loosening of the acetabular component in all 322 hips was 6 per cent (eighteen hips), while in the ninety-eight hips of the patients who were alive at least twenty years after the arthroplasty, it was 10 per cent (ten hips). The rate of revision because of aseptic loosening of the femoral component in all 322 hips was 2 per cent (eight hips), while in the ninety-eight hips of the living patients, it was 3 per cent (three hips).(ABSTRACT TRUNCATED AT 400 WORDS)

Improved cementing techniques have been shown to decrease the rate of aseptic loosening of femoral components of cemented total hip replacements at five to seven years. We now report our results in 105 hips in 93 patients at 10 to 12.7 years (mean 11.2). The improved techniques included use of a medullary plug, a cement gun, a doughy mix of Simplex P and a collared stem of chrome cobalt. Only three femoral components had definitely loosened, none were probably loose and 24 were graded as possibly loose. In contrast, the incidence of radiographic loosening on the acetabular side was 42%. Improved cementing techniques have produced a marked reduction in the rate of aseptic loosening of the femoral component, but the incidence of acetabular loosening is unchanged.

Fifty uncemented porous-coated total hip prostheses were implanted in forty-seven patients whose mean age was fifty-eight years. Clinical hip-rating scores, as described by Harris, were determined and anteroposterior and frog-leg lateral radiographs were made preoperatively, shortly postoperatively, and at three months, six months, one year, and two years postoperatively. The mean hip-rating score was 92 points (range,(range, 74 to 100 points) at one year and 92 points (range, 69 to 100 points) at two years. The thigh was slightly painful in nine patients (18 per cent) at one year and in eight (16 per cent) at two years. Fourteen hips (28 per cent)(in thirteen patients) caused a moderate or severe limp two years postoperatively; however, this complication appears to have been related more to the direct lateral approach that was used than to the prosthesis. Six (13 per cent) of the patients walked with a cane at one year and five (11 per cent) still required a cane at two years. Serial radiographic evaluations revealed that, between the first and second postoperative years, a progressive radiodense femoral line developed in twenty hips (41 per cent); a progressive acetabular line, in four hips (8 per cent); and progressive femoral sclerosis, in twelve hips (24 per cent). There was progressive loosening of beads from twelve (24 per cent) of the femoral components and from nine (18 per cent) of the acetabular components. The position of one acetabular and one femoral component changed. Two femoral shafts fractured, one intraoperatively and one fourteen months postoperatively. We concluded that the clinical results were encouraging in these patients at the end of two years. We are concerned, however, about the progressive radiodense lines, sclerosis, and loosening of beads as well as the slight, but persistent, pain in the thigh in eight patients.