Quantitative analysis of technetium-99m-methylene diphosphonate uptake in unilateral hydroxyapatite-coated total hip prostheses: first year of follow-up.

Abstract

A prospective study was performed on 80 patients who had undergone a unilateral hydroxyapatite (HA)-coated total hip arthroplasty to establish the normal periprosthetic uptake of methylenediphosphonate (MDP) as a function of implant age. Patients were imaged periodically while they were asymptomatic at 1, 3, 6 and 12 mo postoperatively. Quantitative measurements were performed with a region of interest (ROI) technique. The HA-coated and uncoated areas were marked in comparison with the normal contralateral femur. The uptake ratios of the MDP were determined postoperatively in the following 12 mo. It was found that a decrease of the uptake ratios occurred in all ROIs. However, for the HA-coated areas, the uptake ratios still remained raised as a result of bony ingrowth. The results of the first year of follow-up were considered to be a normal database that will be used as a reference when the same group of patients are followed up to 5 yr postoperatively to detect any potential modes of failure of the implant.