Cementless acetabular fixation in patients 50 years and younger at 10 to 18 years of follow-up

The purpose of the study was to evaluate the 10- to 18-year follow-up of cementless acetabular fixation in patients 50 years and younger. We retrospectively reviewed a consecutive group of 118 patients (144 hips) in whom primary total hip arthroplasty had been performed by 2 surgeons using a cementless acetabular component. Two (1.4%) cementless acetabular components were revised because of aseptic loosening. Twenty-four hips (16.7%) were revised for any mechanical failure of the acetabular component mostly related to acetabular liner wear and osteolysis. The average linear wear rate was 0.19 mm per year, which was higher than our previous reports with cemented acetabular fixation. The fiber mesh ingrowth surface of the cementless acetabular component in this study was superior to cemented acetabular components in terms of fixation. However, the high rates of wear and osteolysis have led to poor overall acetabular component construct survivorship.     

Cementless acetabular fixation at fifteen years. A comparison with the same surgeon's results following acetabular fixation with cement

BACKGROUND: Loosening of the acetabular component is the major long-term problem associated with total hip arthroplasty with cement. The purpose of the present study was to evaluate the minimum thirteen-year results associated with cementless acetabular components that had been inserted by a single surgeon and to compare them with the results associated with cemented acetabular components that had been inserted by the same surgeon. METHODS: One hundred and twenty consecutive, nonselected primary total hip replacements were performed in 108 patients with use of a Harris-Galante-I cementless acetabular component and a cemented femoral component with a 28-mm head. The patients were evaluated clinically with use of a standard terminology questionnaire, and they were evaluated radiographically for loosening, component migration, wear, and osteolysis. The rates of revision for aseptic loosening and radiographic evidence of loosening for this cohort were compared with the rates for four previously reviewed consecutive series of hips in which the acetabular component had been inserted with cement. All patients were managed by the same surgeon, were followed for thirteen to fifteen years, and were evaluated with use of the same two criteria (revision and loosening) as the end points for Kaplan-Meier analysis. RESULTS: Sixty-six patients (seventy-two hips) were living and forty-two patients (forty-eight hips) had died after thirteen to fifteen years of follow-up. No acetabular component had been revised because of aseptic loosening, and no acetabular component had migrated. With revision of the acetabular component for any reason as the end point, the survival rate was 81% +/- 8% at fifteen years. With revision of the acetabular component for clinical failure (osteolysis, wear, loosening, or dislocation) as the end point, the survival rate was 94% +/- 8% at fifteen years. Among the seventy hips with at least thirteen years of radiographic follow-up, five had pelvic osteolysis and three had had revision of a well-fixed acetabular component because of pelvic osteolysis secondary to polyethylene wear. The mean linear wear rate was 0.15 mm/yr (0.12 mm/yr when one outlier was excluded). CONCLUSIONS: In terms of fixation, Harris-Galante-I cementless acetabular components performed better than did cemented 22-mm-inner-diameter Charnley acetabular components as well as 28-mm-inner-diameter all-polyethylene and metal-backed acetabular components that had been inserted by the same surgeon. However, the rate of wear was greater in association with the Harris-Galante-I cementless components than it was in association with the Charnley cemented all-polyethylene components.     

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.     

Total hip arthroplasty with a cemented, polished, collared femoral stem and a cementless acetabular component. A follow-up study at a minimum of ten years

BACKGROUND: Recent studies have suggested that cemented femoral components with a polished surface may provide superior long-term fixation when compared with femoral components with a roughened surface. The purpose of this study was to evaluate the results of total hip arthroplasty with a cemented femoral component with a polished surface finish and compare them with the results of total hip arthroplasty performed with a similar design of cemented femoral component with a rougher surface finish. METHODS: We retrospectively reviewed a consecutive group of 132 patients (149 hips) in whom primary total hip arthroplasty had been performed by one surgeon using a cemented collared femoral component with a polished (0.1-microm Ra) surface finish and a cementless acetabular component. Ninety-eight patients (115 hips) were followed for a minimum of ten years. We compared the survivorship of this prosthesis with that of a femoral component of similar design but with rougher surfaces (matte or grit-blasted). RESULTS: No polished stems were revised because of aseptic loosening or demonstrated radiographic evidence of loosening; however, eight hips (5.4%) with a polished stem demonstrated osteolysis distal to the greater or lesser tro-chanter. In contrast, six stems (2.0%) with a matte surface finish of 0.8-microm Ra were revised because of aseptic loosening, and an additional five stems were seen to be loose radiographically. Eleven stems (9.2%) with a grit-blasted surface finish of 2.1-microm Ra were revised because of aseptic loosening, and an additional four stems were seen to be loose radiographically. The difference in the prevalence of revision due to aseptic loosening between the group with the 0.1-microm Ra surface and the group with the 2.1-microm Ra surface was significant (p = 0.001), as was the difference between the prevalence of revision due to aseptic loosening between the group with the 0.8-microm Ra surface and the group with the 2.1-microm Ra surface (p = 0.001). No cups were revised because of aseptic loosening, and one hip had radiographic signs of acetabular loosening. CONCLUSIONS: This study demonstrated excellent durability of a prosthesis consisting of a cemented, collared, polished femoral component and a cementless acetabular component. While no hips were revised because of aseptic loosening, distal femoral osteolysis was observed in eight hips (5.4%), a higher prevalence than has been reported by others after similar durations of follow-up of tapered, collarless, polished femoral components.     

Revision of a cemented acetabular component to a cementless acetabular component. A ten to fourteen-year follow-up study.

BACKGROUND: Although cementless acetabular components are routinely used in revision hip surgery, few investigators have evaluated the retention and efficacy of these components in the long term. In the current study, the clinical and radiographic outcomes of a series of arthroplasties performed by one surgeon with a cementless acetabular component were assessed at a minimum of ten years. METHODS: From 1986 through 1988, sixty-one consecutive revision total hip arthroplasties were performed in fifty-five patients because of aseptic failure of one or both components of a prosthesis in which both components had been cemented. Twenty-eight patients (thirty-two hips) were alive at a mean of 12.9 years (range, 11.5 to 14.3 years) after the operation. In all of the patients, the acetabular component was revised to a porous-coated Harris-Galante component inserted without cement, and the femoral component was revised to an Iowa component affixed with contemporary cementing techniques. The hips were evaluated clinically and radiographically at a minimum of ten years subsequent to the index revision. No hips were lost to follow-up. RESULTS: None of the acetabular components required revision because of aseptic loosening. Two hips (3%) demonstrated radiographic evidence of aseptic loosening of the acetabular component. The polyethylene liner was exchanged during the follow-up period in eight hips. CONCLUSION: After a minimum of ten years of follow-up, cementless acetabular fixation in revision hip arthroplasty had produced durable results that were markedly better than those reported for acetabular fixation with cement.     

Comparison of total hip replacement with and without cement in patients younger than 50 years of age: the results at 18 years

There have been comparatively few studies of the incidence of osteolysis and the survival of hybrid and cementless total hip replacements (THRs) in patients younger than 50 years of age. We prospectively reviewed 78 patients (109 hips) with a hybrid THR having a mean age of 43.4 years (21 to 50) and 79 patients (110 hips) with a cementless THR with a mean age of 46.8 years (21 to 49). The patients were evaluated clinically using the Harris hip score, the Western Ontario and McMaster Universities (WOMAC) osteoarthritis score and the University of California, Los Angeles (UCLA) activity score. Radiographs and CT scans were assessed for loosening and osteolysis. The mean follow-up was for 18.4 years (16 to 19) in both groups. The mean post-operative Harris hip scores (91 points versus 90 points), the mean WOMAC scores (11 points versus 13 points) and UCLA activity scores (6.9 points versus 7.1 points) were similar in both groups. The revision rates of the acetabular component (13% versus 16%) and the femoral component (3% versus 4%), and the survival of the acetabular component (87% versus 84%) and the femoral component (97% versus 96%) were similar in both groups. Although the long-term fixation of the acetabular metallic shell and the cemented and cementless femoral components was outstanding, wear and peri-acetabular osteolysis constitute the major challenges of THR in young patients.     

The influence of technique on fixation of primary total hip arthroplasty in patients with rheumatoid arthritis

This is a prospective, consecutive study of 98 total hip arthroplasties implanted by 1 surgeon in 66 patients with rheumatoid arthritis. The mean follow-up time was 7.4 years (range, 2-13 years). All 98 acetabular components were uncemented titanium fiber metal-coated components fixed with multiple screws. Sixty-five hips had bulk or cancellous allograft for protrusio acetabuli. Following a prospective protocol based on patient age, 51 hips had an uncemented femoral component, and 47 hips had a cemented femoral component. Using the Harris Hip Score, 30 hips were rated as excellent; 44, good; 15, fair; and 9, poor. There were no early deep infections. One hybrid hip was removed for late metastatic infection at 7 years. Radiographic evaluation of 98 acetabular components showed 1 case of septic loosening, 2 cases of aseptic loosening (1 patient asymptomatic), and 1 case with severe wear and ischial osteolysis. None of the 47 cemented femoral components subsided, and osteolysis was seen in only 3 femora (7%). Of the 51 uncemented femoral components, subsidence occurred in 7 hips (14%), and osteolysis occurred in 15 hips (30%). Uncemented acetabular components have a high rate of success in patients with rheumatoid arthritis who have a total hip arthroplasty. There is a high rate of subsidence and osteolysis, however, with first-generation cementless femoral components.     

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

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A cementless elastic monoblock socket in young patients: a ten to 18-year clinical and radiological follow-up

The survival of acetabular components depends on several factors: wear, osteolysis and septic or aseptic loosening. Osteolysis seems to be the main cause for concern in cementless arthroplasties. Acetabular osteolysis results from particle debris and segmental unloading of acetabular bone by rigid sockets. We investigated a cementless elastic monoblock socket with regard to acetabular osteolysis and aseptic loosening in a cohort of young patients. We evaluated 158 hip arthroplasties with a minimum follow-up of ten years (ten to 18) and a mean age of 42 years (18–50). The overall revision rate at 14 years was 80% with a 98% survival rate for aseptic loosening. The mean polyethylene wear rate was 0.11 mm/year. Progressive acetabular osteolysis was seen in 3% of patients evaluated. In conclusion, we found low pelvic osteolysis rates, acceptable overall wear rates, satisfactory overall survival and excellent survival rates for aseptic loosening of a cementless elastic monoblock socket in patients younger than 50 years. Ongoing tribology developments and knowledge about acetabular bone adaptations behind acetabular implants will further lower wear and osteolysis rates and optimise survival rates of cementless sockets.     

Total hip arthroplasty with the use of nonmodular cementless acetabular component

Sixty-seven hips in 63 patients who underwent total hip arthroplasties with the use of the nonmodular cementless acetabular component and alumina-on-polyethylene bearing surface were available for complete clinical and radiographic review at a mean follow-up period of 7 (range 5-9) years. The mean age was 59 years (range 34-75) years. The mean preoperative Harris hip score of 50 points improved to 93 points at final follow-up. One (1.5%) hip required revision for a recurrent dislocation. No component was loose radiographically at final follow-up. The mean linear wear rate was 0.07 (range 0.01-0.23) mm/y. At a mean follow-up of 7 years, there was no aseptic loosening. Further follow-up, however, is necessary to determine the potential advantage of nonmodular acetabular component for the development of pelvic osteolysis.     

Intermediate-term results after hybrid total hip arthroplasty for the treatment of dysplastic hips

BACKGROUND: In recent studies, good intermediate-term results have been reported after primary hybrid total hip arthroplasty (a cementless acetabular component with a cemented femoral stem) for the treatment of primary osteoarthritis. However, few studies have described the results of this technique in patients with developmental dysplasia of the hip. METHODS: One hundred primary hybrid total hip replacements were performed in ninety patients to treat degenerative arthritis of the hip secondary to developmental dysplasia. Seventy-one patients (eighty-one hips) were available for clinical and radiographic evaluation. The average duration of follow-up was 10.6 years. There were ten men and sixty-one women. Seventy hips were classified as type 1 (dysplasia); seven, as type 2 (low dislocation); and four, as type 3 (high dislocation), according to the classification system of Hartofilakidis et al. RESULTS: At the time of the final follow-up, the average Harris hip score was 86 points. Structural autograft was used in fifteen hips to supplement acetabular coverage. Within five years postoperatively, the acetabular component in six of the fifteen hips had an average of 4.5 mm of vertical migration and an average increase in vertical rotation of 3 degrees, but the position appeared to stabilize thereafter. Revisions were performed in two hips because of recurrent dislocation. No acetabular or femoral component was revised because of aseptic loosening. Osteolysis was identified around two acetabular components and two femoral components. The average rate of polyethylene wear was 0.09 mm per year. CONCLUSIONS: Hybrid total hip arthroplasty for the treatment of symptomatic degenerative arthritis secondary to developmental dysplasia provides favorable results at intermediate-term follow-up. With lower grades of dysplasia, the majority of patients can be treated effectively without a structural bone graft by placement of the cementless acetabular component at a medial or high position.     

Evaluation of two surgical techniques for acetabular reconstruction in total hip replacement for congenital hip disease: results after a minimum ten-year follow-up

We have evaluated the results of total hip replacement in patients with congenital hip disease using 46 cemented all-polyethylene Charnley acetabular components implanted with the cotyloplasty technique in 34 patients (group A), and compared them with 47 metal-backed cementless acetabular components implanted without bone grafting in 33 patients (group B). Patients in group A were treated between 1988 and 1993 and those in group B between 1990 and 1995. The mean follow-up for group A was 16.6 years (12 to 18) and the mean follow-up for group B was 13.4 years (10 to 16). Revision for aseptic loosening was undertaken in 15 hips (32.6%) in group A and in four hips (8.5%) in group B. When liner exchange was included, a total of 13 hips were revised in group B (27.7%). The mean polyethylene wear was 0.11 mm/yr (0.002 to 0.43) and 0.107 mm/yr (0 to 0.62) for groups A and B, respectively. Polyethylene wear in group A was associated with linear osteolysis, and in group B with expansile osteolysis. In patients with congenital hip disease, when 80% cover of the implant can be obtained, a cementless acetabular component appears to be acceptable and provides durable fixation. However, because of the type of osteolysis arising with these devices, early exchange of a worn liner is recommended before extensive bone loss makes revision surgery more complicated.     

Long-term survivorship of the Charnley Elite Plus femoral component in young patients

We studied prospectively the long-term results of the Charnley Elite-Plus femoral stem in 184 consecutive young patients (194 hips). There were 130 men and 54 women with a mean age of 49.1 years (21 to 60). The predominant diagnosis was osteonecrosis of the femoral head (63.6%, 117 patients). Clinical and radiological evaluation was undertaken at each follow-up. The mean follow-up was 11.2 years (10 to 12). The mean pre-operative Harris hip score was 43.4 (12 to 49) which improved to 91 (59 to 100) at the final follow-up. The survival of the femoral stem at 12 years was 99% with revision as the end-point. The mean annual linear wear of the polyethylene liner was 0.17 mm (0.13 to 0.22). The prevalence of acetabular osteolysis was 10.8% (21 hips) and osteolysis of the calcar femorale 12.9% (25 hips). A third-generation cementing technique, accurate alignment of the stem and the use of a 22 mm zirconia head were important factors in the prevention of aseptic loosening of the Elite Plus femoral stem in these high-risk young patients.     

Modular cementless total hip arthroplasty for multiple epiphyseal dysplasia

We analyzed a consecutive series of 23 total hip arthroplasties that had been performed using modular cementless prostheses in 13 patients with a confirmed diagnosis of multiple epiphyseal dysplasia and end-stage osteoarthritis of the hip. The average Harris hip score improved from 40.6 to 93.8 points. Postoperatively, all hips demonstrated favorable alterations in the biomechanical parameters including hip center of rotation, femoral offset, femoral neck length, and limb length. At a mean follow-up of 4.8 years, no hip required revision because of aseptic loosening of the acetabular or femoral component. One patient (1 hip, 4.3%) underwent reoperation for polyethylene wear and osteolysis 8 years after index arthroplasty. This study shows encouraging clinical and radiographic outcomes of modular cementless total hip arthroplasties for this technically difficult condition.     

Uncemented metal-on-metal acetabular component: follow-up of 112 hips for a minimum of 5 years

Background Aseptic loosening is the major cause of implant failure. In cemented hip arthroplasty, failure of the acetabular side is mainly due to lysis caused by wear particles. By using an implant with low wear characteristics and by enhancing acetabular fixation using an uncemented implant, we aimed to reduce acetabular lysis and thereby loosening.

Patients and methods This was a retrospective cohort study of 119 hips (101 patients) that had the Uncemented Fitmore cup (Sulzer Orthopedics). In 66 patients, the femoral component was CF-30 (Sulzer) used with cement. In the remaining 35 patients, thrust plate prosthesis (TPP) (Sulzer) was used. Of the 101 patients, 94 (112 hips) were available for study. Mean follow-up of the 94 patients was 7 (5-13) years.

Results The mean preoperative Harris hip score was 38 and the mean postoperative Harris hip score was 89 at the last follow-up. Taking aseptic loosening as the endpoint, the survival rate of the Fitmore cup was 100% at 11 years.

Interpretation The uncemented Fitmore acetabular cup with second generation metal-on-metal articulation showed good results with regard to aseptic loosening in the medium term.     

A constrained liner cemented into a secure cementless acetabular shell

BACKGROUND: Constrained acetabular components have been used to treat hips with recurrent instability following total hip arthroplasty and hips that demonstrate instability during revision surgery. In such hips, when a secure cementless acetabular shell is present, the surgeon can cement a constrained liner into the existing shell. The purpose of this study was to evaluate the clinical and radiographic outcome of this technique with use of a tripolar constrained liner that was cemented into a well-fixed cementless acetabular shell. METHODS: Between 1988 and 2000, constrained liners were cemented into thirty-one well-fixed cementless acetabular shells at three centers. The average age of the patients at the time of the index surgery was 72.1 years, and the indications for the procedure were recurrent hip instability in sixteen hips and intraoperative instability in fifteen hips. The patients were evaluated with respect to the clinical outcome and radiographic evidence of shell loosening and osteolysis. RESULTS: At an average duration of follow-up of 3.9 years, twenty-nine liners (94%) were securely fixed in the cementless shells and two constrained liners had failed. One liner failed because it separated from the cement, and one failed because of fracture of the capturing mechanism. Both hips were successfully revised with another cemented tripolar constrained liner. No acetabular component demonstrated radiographic evidence of progressive loosening or osteolysis. CONCLUSIONS: A constrained tripolar liner cemented into a secure, well-positioned cementless acetabular shell provides stability and durability at short-term follow-up. Careful attention to the preparation of the liner, the sizing of the component, and the cementing technique are likely to reduce the failure of this construct, which can be used for difficult cases of total hip instability.     

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

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

Primary Total Hip Arthroplasty With Duraloc Cup in Patients Younger Than 50 Years : A 5- to 7-Year Follow-Up Study

We evaluated the clinical and radiographic results of 67 (64 patients) cementless Duraloc-300 cups for young active patients after a mean follow-up period of 6.2 years. The preoperative mean Harris hip score improved from 46.24 to 96.5 points at 5 years. The survivorship of the cup, using radiographically confirmed aseptic loosening as the end point, was 100% at 5 years. The mean rate of liner wear was 0.125 mm/y (00-0.39 mm/y). Acetabular osteolysis was found in 14% (9 hips) of the 67 hips, and the osteolysis is related to polyethylene wear (P = .0024) and sex (P = .001). Although there was no aseptic loosening of the components, there was a high rate of liner wear of the polyethylene liner and acetabular osteolysis.     

Use of a constrained tripolar acetabular liner to treat intraoperative instability and postoperative dislocation after total hip arthroplasty: a review of our experience

Constrained acetabular components have been used to treat certain cases of intraoperative instability and postoperative dislocation after total hip arthroplasty. We report our experience with a tripolar constrained component used in these situations since 1988. The outcomes of the cases where this component was used were analyzed for component failure, component loosening, and osteolysis. At average 10-year followup, for cases treated for intraoperative instability (2 cases) or postoperative dislocation (4 cases), the component failure rate was 6% (6 of 101 hips in 5 patients). For cases where the constrained liner was cemented into a fixed cementless acetabular shell, the failure rate was 7% (2 of 31 hips in 2 patients) at 3.9-year average followup. Use of a constrained liner was not associated with an increased osteolysis or aseptic loosening rate. This tripolar constrained acetabular liner provided total hip arthroplasty construct stability in most cases in which it was used for intraoperative instability or postoperative dislocation.