Anatomical reconstruction of high riding hips by total hip arthroplasty (THA) and subtrochanteric shortening osteotomy aims to normalise gait pattern and improve functional hip scores. We present the medium-term clinical results of a group of patients with high riding dislocated hips in whom a cementless THA and subtrochanteric shortening osteotomy had been performed. We compared them with their preoperative status, with patients who had undergone a cementless THA for primary osteoarthritis, and also with a group of healthy gender and age-matched controls. Prospective computerized, three-dimensional gait analyses were performed in 8 female patients with uni-/ or bilateral severe developmental dysplasia of the hip (Group I). Gait analysis was performed preoperatively and at a mean of 12.5 months postoperatively. A group of 8 individuals who received cementless hip replacement for primary osteoarthritis (Group II), and a control group of 8 able-bodied individuals (Group III) were recruited for comparison. Patients in Group I improved and approached the values of Group II. However both were behind Group III. Limb length discrepancy was reduced from a mean of 4.3 cm (range, 1 - 8 cm) to a mean of 0.8 cm (range, 0 - 2 cm) at the latest follow-up. Pain was reliably relieved and activities of daily living were improved in patients with high riding developmental dysplasia of the hip, but they were still behind the normal population average. Nevertheless, the results can be as satisfactory as those in patients who undergo a THA for primary osteoarthritis.

In orthopaedic applications, allografts are used for restoration of bone defects. In order to combine the effects of bone repair and to prevent the infection, antibiotic-impregnated bone grafts are under current investigation with promising early results. In this study, to preserve the stability of antibiotics and to provide appropriate release profiles for 4-6 weeks, antibiotic-loaded microspheres were administered in combination with allografts and vancomycin was the antibiotic loaded to microspheres. Particle size, surface characteristics, loading capacity and in vitro release characteristics of the microspheres with and without allografts were determined. In vivo studies were performed on rabbits and antibiotic amount was determined by a fluorescence polarization immunoassay (FPIA) method from synovial fluid sample aspirated. According to the results, although the in vitro study demonstrated effective antibiotic release of vancomycin from antibiotic-impregnated allografts for 5 weeks, in vivo conditions led to an early instability of the antibiotic (in powder form) and contrary to the high initial loading dose an effective release could not be obtained from the allografts after the first week. Following these studies, it was determined that antibiotic release over a minimum inhibitory concentration (MIC) for 6 weeks was realized from vancomycin-loaded microspheres which were implanted in a blend with allografts in bone defects. In conclusion, preservation of the antibiotic in microspheres maintained the bioactivity and provided the controlled antibiotic release, thus implantation of microspheres in a blend with allografts seemed to be a promising carrier system for the orthopaedic applications.

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