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.
The gap or problem that this research aims to address is the lack of high-quality
evidence on the effectiveness of prophylactic CTL during RSA for preventing or reducing
anterior shoulder pain at one year after surgery. The investigators hypothesize that
patients who undergo prophylactic CTL during RSA will have less anterior shoulder pain at
one year after surgery than those who do not. The investigators will test this hypothesis
by conducting a randomized controlled trial with two groups: CTL group and control group.
The investigators will compare the pain intensity, range of motion, strength, activity
level, and patient-reported outcomes of the two groups at 6 months and 12 months after
RSA. The investigators will also identify the factors that predict the response to CTL,
such as age, gender, body mass index, comorbidities, duration of pain, and severity of
arthritis. This research will contribute to the knowledge in the field of shoulder
surgery by providing high-quality evidence on the effectiveness of prophylactic CTL
during RSA for anterior shoulder pain. This research will also have practical
implications for the field of shoulder surgery by providing a viable option for patients
who suffer from anterior shoulder pain after RSA, and enhancing their function and
quality of life.