The aim of our study is to assess the outcomes using the uncemented CLS expansion shell in revision hip surgery for aseptic loosening of the acetabular component. Between 1991 and 2000 we used the CLS expansion shell in revision hip surgery in 215 patients (230 hips). We were able to evaluate 196 patients (211 hips) with failed acetabular components. The male/female ratio was 82/114 and the mean age of the patients was 63 years (range 38-71). The main reason for revision was aseptic loosening of the PE cup (184 patients). There were 79 hips with Paprosky defect of the acetabulum type I, 62 hips with type 2A, 57 hips with type 2B and 13 hips with type 2C in the study. The mean follow-up was 8.5 years (range 5-14). Plain radiographs using an AP view of the pelvis and AP and lateral views of the affected hip were taken immediately after surgery and at the latest follow-up. Clinical outcomes were determined using the Merle dAubigne' and Postel score and the Harris Hip score. The mean preoperative Merle dAubigne' score was 7.8 points (range 6.9 to 9.9); at the latest follow-up it was 14.9 points (range: 12.5 to 15.9). The mean preoperative Harris Hip score was 38.6 points (range: 32 to 59); at the latest follow-up it was 82.5 points (range: 38 to 95). Osteointegration of the CLS expansion shell was present in 149 hips (70.6%) at the latest follow-up. There were 31 complications (15%) requiring a second revision. Clinical survivorship of the CLS expansion shell was 90% at five years and 84% at 8.5 years after revision surgery. Radiological survivorship was 78% at five years and 70% at 8.5 years after revision surgery. The CLS expansion shell offers a viable alternative for revision hip surgery with lower bone quality, insufficient bone at the bottom and cavitary defects of the acetabulum.;

PURPOSE OF THE STUDYThe aim of the study was to evaluate the results of primary total hip arthroplasty with the use of the CLS stem at 11 to 17 years after implantation. MATERIAL AND METHODSA total of 108 patients (122 hips) in whom a CLS stem was used in the 1991-1996 period were evaluated. The group included 34 men and 74 women, with an average age of 48 years (range, 28-63). The CLS stem with a neck-shaft angle of 145° and the CLS expansion cup were used in all patients. Clinical outcomes were evaluated by Merle d'Aubigné-Postel score and Harris hip score, radiological examination was completed on AP and lateral views of the pelvis and the operated hip. RESULTSThe average follow-up was 16.4 years (range, 11-17). The average Merle d'Aubigné-Postel score was 14.5 (range, 13.9-17.0) points and the average Harris hip score was 84.8 (range, 70-99) points. Very good or good outcomes were found in 81% of the patients. Three patients underwent revision surgery, in one for septic loosening, in one for aseptic loosening and in one for varus stem position leading to instability. The radiographs evaluated as described by Engh showed 116 stable stems, three fibrous stable and three unstable stems. Subsidence of more than 3 mm, without any further deterioration, was found in five hips at 12 months post-operatively. Seven hips showed one radiolucent line, four showed two radiolucent lines and three hips showed three radiolucent lines, all of them being less than 2 mm wide. DISCUSSIONRadiographic evidence of a stable stem in 116 hips (116/122) suggests a high reliability of the implant. Assessment of radiolucent lines showed 108 hips without radiographic demarcation and 11 hips with slight demarcation. The signs of stress-shielding grade 1 were found in 28 hips. Good results of arthroplasty with the CLS stem can be attributed to its threedimensional wedge-shaped design that allows for an optimal press-fit in the metaphyseal region. The porous surface provides reliable osteointegration. Stress-shielding is prevented by optimal stress distribution in the metaphyseal region and by a modulus of elasticity of titanium alloy which closely approximates the modulus of elasticity of bone. CONCLUSIONSAt 15 years post-operatively, the cumulative probability of clinical survivorship of the CLS stem was 98.3 %, and cumulative probability of radiographic survivorship was 87.7 %. The advantages of this stem include a technically simple implantation, reliable osteointegration and long-term stability even in high demanding patients.

The aim of our study is to assess the outcomes using the uncemented CLS expansion shell in revision hip surgery for aseptic loosening of the acetabular component. Between 1991 and 2000 we used the CLS expansion shell in revision hip surgery in 215 patients (230 hips). We were able to evaluate 196 patients (211 hips) with failed acetabular components. The male/female ratio was 82/114 and the mean age of the patients was 63 years (range 38-71). The main reason for revision was aseptic loosening of the PE cup (184 patients). There were 79 hips with Paprosky defect of the acetabulum type I, 62 hips with type 2A, 57 hips with type 2B and 13 hips with type 2C in the study. The mean follow-up was 8.5 years (range 5-14). Plain radiographs using an AP view of the pelvis and AP and lateral views of the affected hip were taken immediately after surgery and at the latest follow-up. Clinical outcomes were determined using the Merle dAubigne' and Postel score and the Harris Hip score. The mean preoperative Merle dAubigne' score was 7.8 points (range 6.9 to 9.9); at the latest follow-up it was 14.9 points (range: 12.5 to 15.9). The mean preoperative Harris Hip score was 38.6 points (range: 32 to 59); at the latest follow-up it was 82.5 points (range: 38 to 95). Osteointegration of the CLS expansion shell was present in 149 hips (70.6%) at the latest follow-up. There were 31 complications (15%) requiring a second revision. Clinical survivorship of the CLS expansion shell was 90% at five years and 84% at 8.5 years after revision surgery. Radiological survivorship was 78% at five years and 70% at 8.5 years after revision surgery. The CLS expansion shell offers a viable alternative for revision hip surgery with lower bone quality, insufficient bone at the bottom and cavitary defects of the acetabulum.;