AC joint reconstruction

Overview

Shoulder joint anatomy showing the humeral head, glenoid socket, and rotator cuff muscles (supraspinatus and infraspinatus). — **Shoulder anatomy.** The shoulder is a shallow ball-and-socket joint. The top of the upper-arm bone (humerus) sits against a small dish on the shoulder blade (glenoid), and four rotator-cuff tendons wrap around the ball to hold it centered during every arm motion.

An AC joint separation tears the ligaments that hold the clavicle in its anatomic position over the acromion. Mild separations recover with rehab, but high-grade injuries — in which the clavicle rides far above the acromion and the deltopectoral fascia is disrupted — produce persistent deformity, weakness, and pain. Reconstructing the torn ligaments restores the clavicle to its anatomic position.

How the Procedure Works

We reduce the clavicle back to its anatomic position first — confirming the reduction fluoroscopically — then hold it there while we reconstruct the coracoclavicular ligaments. A tendon graft is looped around the coracoid base and passed through two drill holes in the clavicle that correspond to the conoid and trapezoid ligament footprints; reconstructing both limbs of the coracoclavicular complex is more stable than a single-tunnel technique. Suspensory fixation (a cortical button or similar device) holds the reduction while the graft incorporates over three to four months. The AC joint capsule is repaired over the top. Over-reduction — pulling the clavicle below its anatomic level — is a recognized complication that affects shoulder mechanics, so we verify position carefully before final fixation.

When to Consider AC Joint Reconstruction

AC joint reconstruction is generally offered when symptoms, imaging, and a trial of non-operative care together point to surgery as the next step. The typical picture includes:

High-grade AC separation
Rockwood type IV, V, or VI injuries where the clavicle is grossly displaced.
Persistent pain after rehab
A high-grade separation with ongoing symptoms or functional deficit despite a course of conservative care.