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At the Orthopaedic Clinic of the Institute for Postgraduate Medical Training in the course of 10 years (1979-1989) 2340 primary implantations of total endoprostheses of the hip joint were performed. During the same period 168 total endoprostheses of the hip joint and 20 cervico-occipital prostheses were reoperated. The most frequent reason for reoperation was aseptic loosening of the acetabular component. The mean period between operation and reoperation in these patients was 98 months. In the group with loosening of the socket associated with mechanical destruction of the component the mean period which had elapsed since the primary operation was 43 months. In 87% small size sockets were involved. The most serious problem of reoperation of total endoprostheses of the hip joint is replacement of bone defects. During reoperation of acetabular components an isolated defect on the floor of the acetabulum was found in 26%, a defect of the margins in 38% and a combined defect of the margins in 26% of the patients. For treatment of the defects the authors used bone grafts in the majority allogenic grafts were involved which were used to reconstruct the margins and floor of the acetabulum. Metal implants should hold the bone grafts in the desired position and should not serve as a skeleton. Reoperation of the acetabular part of total endoprostheses of the hip joint is easier from the technical aspect; in defects of the upper portion of the femur it is essential to use a very careful procedure and to preserve the skeleton to a maximal extent.(ABSTRACT TRUNCATED AT 250 WORDS)

The authors have made electromyographic examination of m. tensor fasciae latae and m. glutaeus medius and sometimes also minimus in patients after the implantation of total endoprosthesis of the hip joint by anterolateral Watson - Jones approach and transgluteal Bauer approach with the aim to find out if there occurs the anticipated transection of n. glutaeus usp. and dennervation of m. tensor fasciae latae and compare from this viewpoint both approaches. The examination was performed in 18 patients after the implantation of 20 total endoprostheses of the hip joint (out of which 10 hip joints were operated on by Watson - Jones approach and 10 by Bauer approach) in the period of 6-20 weeks after operation. In the examination concentric needle electrodes and NEUROMATIC 2000 C device (produced by DANTEC Co.) were applied. It was found out that the transection of n. glutaeus sup. is inevitable in neither approach. In patients operated on by Watson-Jones approach there occurred only twice complete transection of the nerve with the dennervation of m. tensor fasciae latae, six time incomplete interruption of the nerve and twice the finding in m. tensor fasciae latae was normal. In patients operated on by Bauer approach complete transection of n. glutaeus sup. was found out six times and incomplete interruption of this nerve four times. Thus from this viewpoint Watson-Jones approach is more considerate. Moreover, in Bauer approach eight times there occurred partial interruption of the innervation of the ventral portion of m. glutaeus medius. Consequently, the study has not proved the assumption that both approaches must necessarily result in complete transection of n. glutaeus sup.(ABSTRACT TRUNCATED AT 250 WORDS)