Prophylactic Conjoint Tendon Lengthening During Reverse Shoulder Arthroplasty: is There a Difference in Anterior Shoulder Pain At One Year After Surgery?

Reverse shoulder arthroplasty (RSA) is a surgical procedure that is used to treat severe shoulder arthritis with rotator cuff damage. RSA involves reversing the ball and socket of the shoulder joint, such that the ball is attached to the shoulder blade and the socket is attached to the upper arm bone. This allows the deltoid muscle to take over the function of the rotator cuff and provide more stability and mobility to the shoulder. RSA has been shown to improve pain, function, and quality of life in patients with various shoulder conditions, such as rotator cuff tear arthropathy, glenohumeral osteoarthritis, complex proximal humeral fractures, pseudoparalysis, and revision shoulder arthroplasty.

However, some patients may experience persistent anterior shoulder pain after RSA, which can limit their function and quality of life. The exact cause and prevalence of this complication are not well understood, but several possible mechanisms have been proposed, such as impingement, instability, infection, nerve injury, fracture, scapular notching, and conjoint tendinitis.

Conjoint tendinitis is a condition where the tendon that connects the coracoid process to the upper arm bone, called the conjoint tendon, becomes inflamed and painful. The conjoint tendon is part of the biceps muscle and the coracobrachialis muscle, and it plays a role in shoulder flexion and internal rotation. Conjoint tendinitis may occur after RSA due to the increased tension and compression on the anterior shoulder caused by the shift in the center of rotation of the joint. Conjoint tendinitis may manifest as anterior shoulder pain, tenderness over the coracoid process, and decreased range of motion and strength.

Conjoint tendon lengthening (CTL) is a surgical procedure that involves cutting or lengthening the conjoint tendon, which may relieve the pain by reducing the tension and compression on the anterior shoulder. CTL can be performed as a primary procedure during RSA, or as a secondary procedure after RSA. The rationale for performing CTL as a primary procedure is to prevent the development of conjoint tendinitis and anterior shoulder pain after RSA. The rationale for performing CTL as a secondary procedure is to treat the patients who have failed conservative treatments, such as physical therapy, injections, or medications, and have persistent anterior shoulder pain after RSA.

The literature on CTL for anterior shoulder pain after RSA is scarce and mostly consists of case reports and case series. There is no randomized controlled trial or systematic review on this topic. The existing studies have reported favorable results of CTL, with improvement in pain, function, and patient-reported outcomes. However, the studies have also acknowledged the limitations of their methods, such as small sample size, lack of control group, short follow-up, and potential bias. Therefore, the evidence for the effectiveness of CTL for anterior shoulder pain after RSA is weak and inconclusive.