International orthopaedics
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Whilst advances in cementing technique have led to improvement in the survival of cemented femoral stems in total hip arthroplasty (THA), cup failure due to aseptic loosening remains a major clinical problem. These observations have led to a move away from cemented cup designs, particularly in young patients, towards uncemented implants. The Plasmacup is a hemispherical, press-fit, cementless, titanium-shelled, acetabular component with a polyethylene liner. ⋯ Four cups had small radiographic areas of focal osteolysis and three had been revised (two for recurrent dislocation and one for deep sepsis; none were revised for aseptic loosening). The mean linear wear rate in this series was 0.14 mm/year. In conclusion, the Plasmacup shows satisfactory early stability, a wear rate similar to other uncemented cups, and favourable mid-term clinical function and survival rates.
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Between 1974 and 1999, we treated operatively 28 patients with a symptomatic mid-shaft clavicular non-union using AO osteosynthesis, including bone grafting. Nine patients had a wave-plate osteosynthesis and 19 a standard AO/ASIF osteosynthesis. The mean follow-up was 10 (2-25) years. ⋯ Pre-operatively, brachialgia was present in 12 patients. Of these patients, six were treated using standard osteosynthesis technique and six by wave-plate osteosynthesis. Post-operatively, patients treated by wave-plate osteosynthesis had no brachialgia and also had a higher Constant score than those patients treated using standard AO/ASIF techniques.
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The BiCONTACT femoral stem for cementless fixation is being used without any technical modification after 15 years. The long-term results should be evaluated in this study. A consecutive series was continuously monitored in a prospective follow-up study. ⋯ Clinical results were somewhat compromised by a higher-than-average rate of cup loosening (uncoated threaded cup). The average Harris hip score at follow-up was 84.3 points. Interestingly, no femoral osteolysis could be detected, even in cases with severe acetabular osteolyses, indicating sealing of the stem interface by tight osseointegration of the proximally-coated stem.
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Comparative Study
Distraction osteogenesis by Ilizarov and unilateral external fixators in a canine model.
We studied distraction osteogenesis in canine experimental model using two types of external fixators, Ilizarov (n=6) or AO unilateral (n=9) external fixator. Distraction started 1 week after surgery (2 x 0.5 mm/day) and lasted for 3 weeks. Specimens were harvested from weeks 7 through 12. ⋯ No differences in histomorphometric parameters existed between the groups. In the study period, the bone formation was enhanced and prevailed in the distraction area. This study demonstrated the utility of the canine experimental model for the study of distraction osteogenesis.