Conclusions
Our results suggest that altered mechanical loading after rotator cuff tears is the primary factor in cartilage degeneration after rotator cuff tears. Clinically, understanding the process of cartilage degeneration after rotator cuff injury will help guide treatment decisions in the setting of rotator cuff tears. Level of evidence: Basic science study, animal model.
Methods
We used a rat model that accurately reflects rotator cuff muscle degradation after massive rotator cuff tears through either infraspinatus and supraspinatus tenotomy or suprascapular nerve transection. Using a modified Mankin scoring system, we found significant glenohumeral cartilage damage after both rotator cuff tenotomy and suprascapular nerve transection after only 12 weeks.
Results
Cartilage degeneration was similar between groups and was present on both the humeral head and the glenoid. Denervation of the supraspinatus and infraspinatus muscles without opening the joint capsule caused cartilage degeneration similar to that found in the tendon transection group. Conclusions: Our results suggest that altered mechanical loading after rotator cuff tears is the primary factor in cartilage degeneration after rotator cuff tears. Clinically, understanding the process of cartilage degeneration after rotator cuff injury will help guide treatment decisions in the setting of rotator cuff tears. Level of evidence: Basic science study, animal model.