Comparison of three methods of gluteal muscle attachment to an allograft/endoprosthetic composite in a canine model

This study used radiography, gait analysis, gluteal muscle mass, mechanical testing, and qualitative histology to compare three methods of gluteal mus cle attachment to an allograft/endoprosthetic composite of the proximal 25% of the femur in an in vivo canine model. The three methods of gluteal musc le attachment were identical to those used clinically in human patients for hip revision and proximal femoral limb salvage: the host gluteal tendon su tured to the allograft tendon (tendon group), the host greater trochanter w ith intact gluteal tendons secured to the allograft with a cable-grip syste m (grip group), and periosteally vascularized proximal femoral bone onlay w ith intact tendons wrapped around the allograft (wrap group). On the basis of radiographs taken every 2 months, the tendon group had more graft fractu res than did the grip or wrap group. Radiographic union of the graft-host b one junction occurred more rapidly and there was less graft resorption in t he wrap group than in the other two groups. In all dogs, peak vertical grou nd-reaction forces in the treated limb decreased immediately after surgery and then slowly increased over the length of the study. The dogs in the wra p group regained normal weight-bearing on the treated limb more quickly tha n did those in the other groups. The constructs in the tendon group were we aker and less stiff immediately after surgery than were those in the other groups or in intact controls. Histologic analysis confirmed that the wrap t echnique resulted in complete union of the host bone-allograft junction mor e often than did the: other techniques. The wrap method had the best functi onal outcome after 9 months when an allograft/endoprosthetic composite was used during total hip arthroplasty in this canine model.