Densitometric changes of the patella in patients undergoing unilateral knee arthroplasty.

INTRODUCTION: Although the intervention of knee arthroplasty became routine, there is no standard reference on the densitometric characteristics of the patella before and after surgery. Scope of this work is the evaluation of patellar bone density before and after unilateral knee arthroplasty.

PATIENTS AND METHODS: BMD was assessed by DEXA examination in 146 individuals, who have been divided into three distinct groups. Group I: 68 subjects with a mean age of 70.6 years, with an unilateral femoral-tibial knee prothesis. Group II: healthy subjects of similar age (average: 64) and without implants. Group III: healthy adults with a mean age of 26.6 years. The follow-up was performed at 6 months to a maximum of 2 years post surgery.

RESULTS: The results were obtained from 68 subjects examined with the DEXA software dedicated to the forearm, which turned out to be the most appropriate for our purpose. The follow-up performed every 6 months after surgery showed a reduction of the density values in the operated knee in the 1st control with a return to the pre-surgiucal situation in the control performed after 1 year. In subsequent checks there was a further increase of the patellar density of the operated knee.

CONCLUSION: Patellar DEXA examination is recommended as an addition to the clinical and radiological standard examination.