Biceps detachment decreases joint damage in a rotator cuff tear rat model

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Musculoskeletal Research

Background:

• Long head of biceps tendon pathology frequently co-occurs with rotator cuff tears.
• Arthroscopic tenotomy is a common treatment, but its effects on shoulder structures are not fully understood.

Purpose of the Study:

• To investigate the effects of detaching the long head of the biceps tendon on shoulder function and joint integrity in the presence of supraspinatus and infraspinatus tears.
• To hypothesize that biceps detachment would negatively impact shoulder function and joint properties.

Main Methods:

• A rat model was used to induce overuse and then detach the supraspinatus and infraspinatus tendons, with or without the long head of the biceps tendon.
• Animals resumed activity, and biomechanical and histological properties of the subscapularis tendon and glenoid cartilage were assessed at 8 weeks.

Main Results:

• The group with biceps tendon detachment showed improved shoulder function, indicated by decreased braking and vertical force.
• This group also exhibited increased subscapularis tendon modulus but no changes in glenoid cartilage modulus.
• Significantly lower cell density was observed in the subscapularis tendons, while cartilage histology remained unchanged.

Conclusions:

• Detachment of the long head of the biceps tendon, alongside a posterior-superior cuff tear, led to enhanced shoulder function and reduced joint damage in this animal model.
• Findings support tenotomy for managing long head of the biceps pathology in two-tendon cuff tears, warranting further clinical investigation.