Scintigraphic control and x-ray findings following the cement-free implantation of the PM shaft in connection with hip joint allo-arthroplasty

147 bone scans with 99mTc-MDP following 60 cementless hip arthroplasties were analysed at 3 to 160 weeks after operation. Results are compared to clinical evaluation according to Merle d'Aubigné. X-ray changes in a number of patients are included. In uncomplicated cases, bone scan activity decreased quickly within 26 weeks postoperatively. Decrease of scintigraphic activity was markedly delayed in patients with low Merle d'Aubigné values or persisting pain. In 4 cases, bone scan activity increased again. In these cases, reoperation revealed rotational instability of the shaft endoprostheses. Unusual x-ray phenomena such as development of a bony cup at the tip of the prosthesis or seams were found mainly in patients with less satisfying results. We consider nuclear imaging an important additional examination to evaluate bony integration of PM shaft endoprostheses after hip replacement, especially as interpretation of x-ray features alone is still doubtful.