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

UNLABELLED: 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.
METHODS: 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.
RESULTS: 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.
CONCLUSION: 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.