TOTAL HIP-REPLACEMENT WITH SOLID AUTOLOGOUS FEMORAL-HEAD GRAFT FOR HIP-DYSPLASIA

Acetabuloplasty with solid autologous femoral head graft for the treat ment of hip dysplasia is an established method which creates the conta ined cavity needed to accommodate the artificial cup. In order to eval uate the medium- and long-term results of this method using a cementle ss hemispheric cup, 34 patients (39 hips) operated on between 1979 and 1986 were clinically and radiologically reviewed. The minimal follow- up was 5 years (average 7.6 years). The Harris hip score increased fro m 36 points preoperatively to 89 points 1 year postoperatively and to 85.1 at the last follow-up. On roentgenographic evaluation, all grafts had been incorporated and appeared to have tolerated the mechanical l oading well. Partial resorption of the graft occurred in 22 of the 39 hips, mainly in the lateral non-loaded zone. Twenty-nine of the 39 ace tabular components showed migration, on average 4.2 mm cranially and 1 .8 mm medially; 92% occurred during the first 2 years, and thereafter it was not progressive. Smaller cups migrated consistently more than l arger cups. A significant correlation was found between cup migration and the degree of bone coverage of the cup, and extensive migration oc curred in most cases with cup coverage by the host bone of less than 4 0%-50% of the weight-bearing surface of the cup. Only one acetabular c omponent was altered significantly, and another appears to have become loose. The use of normal-sized cups and cementless fixation medially in the primary acetabulum are thought to have contributed to our favor able mid- to long-term results. The substantial migration rate during the first 2 years was not related to loosening, and it did not continu e to progress. Apparently, some migration must be accepted, and this d oes not necessarily correspond to cup loosening.