Latissimus Dorsi (and Teres Major) Rupture

A sudden posterior-axillary pain and bruising with weakness in a thrower, and an MRI showing a latissimus dorsi tendon avulsion, is a posterior-axillary-fold injury - rupture of the latissimus dorsi, with or without the teres major, the muscles that extend, adduct and internally rotate the arm and form the posterior axillary fold. These are uncommon injuries seen in throwing and overhead athletes and classically in water-skiers, through a sudden eccentric load. The diagnosis is clinical - the posterior-axillary defect, bruise and weakness, with loss of throwing power - confirmed by MRI, which I would use not only to confirm the tear but to determine which of the two tendons is involved and the degree of retraction, both of which inform treatment. The management decision is individualised and hinges on the patient's functional demand and the tear pattern. Many of these injuries, particularly partial tears and tears in recreational athletes, do well with non-operative treatment - rest, structured rehabilitation and a graded return - with good functional recovery. But this patient is a high-demand professional thrower with a complete avulsion, who needs full extension, adduction and internal-rotation power for performance, and that is exactly the situation in which surgical repair is considered: re-attachment of the avulsed tendon, for example through a single-incision axillary approach with suture anchors, which has reported good return to sport, though it requires technical expertise because of the neurovascular structures. So I would discuss the options with the athlete and, given the complete avulsion and his high demand, lean towards surgical repair as part of shared decision-making.