PROLONGED PROGRESSIVE CALCANEAL BONE LOSS DESPITE EARLY WEIGHTBEARINGREHABILITATION IN PATIENTS SURGICALLY TREATED FOR ACHILLES TENDINOSIS

We prospectively evaluated areal bone mineral density (BMD) of the cal caneus and calf-muscle strength (concentric and eccentric plantar flex ion peak torque in Nm) in 10 recreational athletes (5 males and 5 fema les), mean age 40.9 years (range 26-55), who were selected to undergo surgical treatment for chronic Achilles tendinosis localized at the 2- 6 cm level. Surgery was followed by immobilization in a plaster cast f or 2 weeks, followed by flexibility training and slowly progressing st rength training and weight-bearing activity. One patient was excluded after week 0 because of a new injury. Seven patients were back to thei r preinjury activity at the 26-week control, and eight patients at the 52-week control postoperatively. BMD in the calcaneus and calf-muscle strength on the injured and noninjured side was measured preoperative ly (week 0) and postoperatively (weeks 2, 6, 16, 26, and 52). There we re no significant differences in BMD between the injured and noninjure d side at weeks 0, 2, and 6, but at weeks 16, 26, and 52, BMD was sign ificantly (P < 0.05) lower (11.5%, 18.4%, and 16.4%, respectively) in the calcaneus of the injured side. Concentric and eccentric plantar fl exion strength were significantly lower on the injured side preoperati vely. Eccentric, but not concentric plantar flexion strength had recov ered compared with the noninjured side 1 year postoperatively. Calf-mu scle strength was not related to bone mass in the calcaneus. As a comp arison, we used a group of 11 recreational athletes (10 males and 1 fe male), with a mean age of 46.1 years (range 28.9-58.5) who had been su rgically treated for chronic Achilles tendinosis at the 2-6 cm level 3 9.5 +/- 11.8 months ago. In this group, there was no significant diffe rence in BMD of the calcaneus between the injured and noninjured side. It seems that there was a delayed and prolonged calcaneal bone loss d espite early weightbearing loading in patients surgically treated for chronic Achilles tendinosis at the 2-6 cm level. Around that time, whe n the Achilles tendon had healed (4-6 months) and the athletes returne d to their sports, the calcaneal bone had a relatively low BMD and mig ht possibly be vulnerable to heavy loadings. There were no signs of re covery 1 year postoperatively, but in a comparison,stoup there were no significant side-to-side differences 39.5 months postoperatively.