Bipolar versus total hip endoprosthesis: functional results.

Some functional parameters of the hip-joint 3.3 years on average (range 2-8.6 years) after hip arthroplasty are compared with regard to two types of hip endoprostheses: the total (TEP) and the bipolar (BPEP). Flexion, extension, abduction, adduction, and internal and external rotation were measured for 75 patients with BPEP type Self-Locking, for 11 patients with BPEP type Vario-Cup, and for 43 with TEP type Lubinus. One-way analysis of variance with respect to co-variances was used for statistical testing of the measured data. It was found that flexion, abduction and adduction were significantly higher in the BPEP endoprosthesis (P < 0.05). The results obtained are favourable for the bipolar hip endoprosthesis, and they can be related to the biomechanical differences between both types of hip endoprosthesis.