gms | German Medical Science

Objectives: This study focused on 10-year follow-up of patients after use of the CoC bearing couple in recording postoperative outcomes and complications using standard scoring systems, radiographic image analysis, and adverse event reporting.

Methods: A multi-centre, prospective, non-controlled and non-randomized, post market surveillance study has been initiated in 2010 and considers 183 hips for the preoperative assessment, 152 hips after 6 months, 163 hips after 1 year, 153 hips after 2 years, 138 after 3 years, 139 hips after 5 years, 127 hips after 7 years and 115 hips after 10 years. The study patients received a total hip arthroplasty with the Allofit IT Cup, a BIOLOX Delta Taper liner and a compatible femoral stem with a BIOLOX delta femoral head. The performance of Ceramic Bearing System was derived from the Harris Hip Score, SF-12, EQ-5D, UCLA analysis and a noise questionnaire. The AL Radiographs of pelvis and Axial Radiographs of the hip joint were evaluated for position of the acetabular cup by inclination and anteversion as well as for position of the stem. Acetabular and femoral side were radiographic alalysed for events (cup migration, radiolucency, osteolysis).

Results and conclusion: The mean Harris Hip Score increased significantly from 49.0 points (Standard Deviation=SD 11.4) pre-operatively to 94 (SD 11.2) points 10 years after surgery (p < 0.0001). The mean UCLA increased from 4.3 points (SD 1.6) pre-operatively to 6.5 (SD 1.7) points 10 years after surgery (p < 0.0001). Also the SF-12 increased significantly; the physical health part from 28.8 (SD 7.1) points pre-operatively to 48 points (SD 9.9) 10 years after surgery (p < 0.0001) and the mental health part from 45.0 (SD 11.9) points pre-operatively to 54.4 points (SD 8.2) 10 years after surgery (p < 0.0001). The mean EQ-5D increased significantly from 0.4 (SD 0.3) preoperatively to 0.8 (SD 0.2) 10 years after surgery (p < 0.0001). Patients who reached the 10-year follow-up (n=115) were either satisfied (n=21) or very satisfied (n=94). 28 of the 115 patients had noise in their hip (24%) with all types of noises. In 6 cases a cup migration of 0.3-0.9mm was reported. Radiolucency was reported a total of 19 times and affected 8 patients. Stem subsidence was reported a total of 11 times and affected 11 patients. Calcar resorption was reported a total of 21 times and affected 9 patients. Heterotopic ossification was reported 176 times and affected 43 patients.

The long-term clinical and radiological data of the 115 patients after 10 years shows good results. The clinical scores increased significantly after surgery – patients are doing well with Ceramic Bearing System. A survival rate of 96.72% for the endpoint revision of any investigational device for any reason after 10 years could be calculated. There were 6 revisions performed. The patients did not have any functional limitations and, with the exception of 1 patient, did not have pain. The noise did not affect the patient’s everyday life, social life or exercise.