Second Rib Stress Fracture After First Rib Resection in a Collegiate Baseball Catcher

BACKGROUND: Thoracic outlet syndrome (TOS) affects overhead athletes and may require surgical decompression. Altered shoulder girdle biomechanics following surgery may increase stress on adjacent ribs, making postoperative posterior shoulder pain a diagnostic challenge that should consider the development of a rib stress injury. CASE PRESENTATION: This case report describes a 21-year-old Division I collegiate baseball catcher who underwent first rib resection, scalenectomy, and thrombectomy for TOS and subsequently developed a second rib stress fracture with bony nonunion. The injury presented as posterior shoulder pain, delaying diagnosis and return to play. OUTCOME AND FOLLOW-UP: The athlete completed 26 physical therapy sessions over 15 weeks, demonstrating improvements in KJOC 12 (44.3% to 96.3%; Minimal Detectable Change=11.5% 17 ) and OSPRO-YF (2YF to 0YF), with isokinetic strength exceeding limb symmetry benchmarks. He resumed throwing at 5 months and returned to competitive catching at 8 months following initial injury. DISCUSSION: Second rib stress fracture should be considered in overhead athletes with prior TOS surgery who develop posterior shoulder pain during return to sport.