Mac Lauglhin defects of the right humeral head developed in a 44-year-old woman with drug-resistant epileptic seizures, subsequent to recurrent posterior dislocations. The preoperative work-up demonstrated a large anterior defect corresponding to more than 50% loss of the osterochondral tissue. The humeral head lodged on the posterior rim of the scapular glenoid, like an inveterate posterior dislocation, causing major pain and joint dysfunction. After adjustment of the antiepilepsy treatment, the patient underwent joint reconstruction with a chondrocostal autograft harvested from the ninth homolateral rib combined with transfer of the lesser tubercle. At three years follow-up, the patient has a stable pain-free shoulder with a satisfactory range of motion. The graft was integrated.