Long-lasting over-elevated stress on the hip joint articular surface can damage the articular cartilage and is connected with arthrosis development. Periacetabular pelvic osteotomy is performed in order to prevent arthrosis development in different cases of residual hip dysplasia where the stress on the hip joint articular surface is increased because of inadequate femoral head coverage, i.e., too small hip joint weight bearing area. The aim of this work is to estimate a decrease of the stress on the hip joint articular surface after the periacetabular osteotomy. For this purpose, a three-dimensional mathematical model is constructed taking into account the spherical shape of the femoral head and of the acetabulum inner surface before and after the operation. On the basis of the presented results it is concluded that while performing the periactabular osteotomy the proximal part of the acetabulum should be rotated over the femoral head in lateral direction with the simultaneous medial displacement of the whole joint. In this way postoperative stress on the hip joint articular surface is reduced to the greatest extent.

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Nine neurologically intact subjects were studied to demonstrate the feasibility of stimulating the muscles of expiration during, and in synchrony with, naturally occurring breathing. A breath-by-breath analysis showed that both tidal volume and the frequency of respiration could be increased during periods of electrical stimulation. A single subject with complete spinal cord injury was studied to eliminate the possibility that the results from the normal subjects could be attributed entirely to either subconscious or conscious volitional response to the stimulation. The results provide a basis for future studies with patients in borderline ventilatory failure.

This presentation will review briefly the current practice and state of the art in functional electrical stimulation (FES) as applied to stroke, head injured or brain tumour operated patients. A similar application is used in paretic patients following trauma or other aetiology. Over 20 years experience in the application of FES, as practised in Ljubljana, will be highlighted and the devices currently in use will be described. The statistics show the results obtained on 2,500 hemiplegic patients examined for FES application during the last 10 years. The statistics and results of the Slovenian population indicate 0.15–0.20% new cases annually or 1,500 new cases per million inhabitants. Up to 63% of annual cases are candidates for an FES based therapeutic locomotion rehabilitation programme. Experience indicates that 60% of hemiplegic patients received single-channel stimulation to correct equinovarus or foot drop, 30% obtained dual or even three channel stimulation treatment and only 10% of patients were involved in multichannel FES of four to six or even eight channels of stimulation. The benefits and outcome of rehabilitation will be presented and discussed in regard to current trends in the field of FES for hemiplegic and paretic patients. The partly inactive but very important field of FES application to the upper extremity in hemiplegic and paretic patients will be discussed and the relatively modest achievements presented. Future developments will be presented together with advances foreseen by steadily improving technology.