Function of the rabbit supraspinatus muscle after detachment of its tendon from the greater tubercle. Observations up to 6 months.

The supraspinatus tendon was detached from the greater tubercle in 30 rabbits. After 6 weeks (group A), 3 months (group B) and 6 months (group C) in vivo evaluation of the twitch-tension and fatigue index were done. Next the scapulas with muscles were examined by CT. During the first 6 weeks a marked reduction in power and fatigue index by about 20% and 10-15%, respectively, in comparison with the control side was noted. These findings remained unchanged at 3 and 6 months. The CT examination showed fatty muscle degeneration, mainly in the 1/3 distal part of supraspinatus, but not in the infraspinatus muscle.