Cementless Total Hip Arthroplasty Using the COREN Hip System: A Minimum Five-Year Follow-up Study

PURPOSE: This study presents the clinical and radiological outcomes of cementless total hip arthroplasty using the COREN hip system after a minimum duration of follow-up of 5 years. MATERIALS AND METHODS: We evaluated the results of a consecutive series of the first 200 primary total hip arthroplasties that had been performed in our hospital in 169 patients between February 2007 and April 2011. Six patients (6 hips) had died within 5 years, and 12 patients (13 hips) had been lost to follow-up, leaving a total of 151 patients (181 hips) available for the study. All patients were evaluated clinically and radiologically with special attention to thigh pain, implant fixation, radiolucent line and osteolysis around implants. RESULTS: The mean Harris hip score improved from 59.4 preoperatively to 97.2 postoperatively. No patient complained of thigh pain. All implants demonstrated radiographic evidence of stable fixation by bone ingrowth without any change in position. No implant was loose radiographically or was revised. Eleven hips (7.7%) had a radiolucent line around the femoral stem. Focal osteolytic area was detected in 3 cases (2.1%). An osteolytic lesion was stabilized in 1 case and further observation was needed in 2 cases in which the lesions were detected several years after surgery. Stress shielding was observed in 80.3% of cases (first degree, 35.9%; second degree, 44.4%); there were no cases of third or fourth degree stress shielding. One case was complicated by bacterial infection and repeated dislocation. CONCLUSION: Mid-term results of total hip arthroplasty using the COREN hip system are very encouraging clinically and radiologically.