DHS SCREW PLATES FOR TROCHANTERIC FRACTURES - IMPACTION ANALYSIS ACCORDING TO FRACTURE TYPE

Introduction The sliding plate has appeared to be a reliable answer fo r trochanteric fractures. However, impaction allowed by the material m ay, have an adverse effect (medialisation, shortening, jutting out of the lag screw). The aim of our study was to measure the sliding of the screw in order to assess the impaction in various types of fracture, according to the Ender classification. Material and methods Hundred tr ochanteric fractures have been treated between 1991 and 1993. Eighty t our have been analyzed with a follow-up of three months after surgery. The average age was 80,1 years with a 4,2 sex ratio (16 males). One h undred and thirty five degrees free sliding plates were employed for f racture fixation. Full weight bearing was allowed in 78,6 per cent of patients. According to Ender classification, 35 per cent of fractures were type 1,4 or 5. This was the first group. The second group consist ed of types 2 and 3 and the third group of types 6, 7 and 8. The resul ts were assessed on AP and lateral X-rays. The ratio between screw thr ead length (constant) and screw outside the barrel length, was used to measure impaction on AP view. Osteoporosis was evaluated according to Singh. Results Despite two screw protrusions out of the femoral head and two failures of the plate, we have observed a healing rate of 100 per cent after three months. Sliding averaged 6,2 mm in group 1, 10,5 mm in group 2 and 16,4 mm in groupe 3. Weight bearing had a low influe nce on the amount of sliding. Discussion Group 1 consists of fractures (types 1, 4 and 5) which are two parts fractures considered as stable . Group 2 corresponds to types 2 and 3 considered as intermediate frac tures with relative stability. In group 3 (types 6, 7 and 8) we have o bserved major fracture instability. Osteoporosis does not seem to be t he major factor regarding screw sliding. Conclusion The sliding plate is reliable. However, complex fractures healed in a wrong position whi ch is definitely not acceptable, especially for young patients. Theref ore, we advise to avoid the use of sliding plate in case of Ender type 6, 7 and 8.