Elbow Medial Ulnar Collateral Ligament (UCL) Injury (Tommy John)

The medial elbow is stabilised by the ulnar collateral ligament complex, of which the anterior bundle - running from the medial epicondyle of the humerus to the sublime tubercle of the ulna - is the primary restraint to valgus and the structure injured in throwers. The injury results from repetitive valgus overload in the late-cocking and early-acceleration phases of throwing. On examination I would localise medial elbow tenderness over the UCL, perform the valgus stress test at about 30 degrees of flexion looking for laxity and pain, and - the most useful test - the moving valgus stress test, applying a valgus force while moving the elbow through its arc, which reproduces the patient's pain typically between about 70 and 120 degrees; the milking manoeuvre is a further valgus-stress test. I would always assess the ulnar nerve, since ulnar neuritis frequently coexists, and check the flexor-pronator origin. To confirm, MRI - often MR arthrography - is the imaging standard; a partial undersurface tear classically shows the T sign, with contrast tracking around the sublime tubercle, and dynamic ultrasound can demonstrate valgus laxity. Plain films may show traction spurs or loose bodies.

Management is graded by the tear and the athlete's demands. For a partial or low-grade tear, especially in-season, I would trial non-operative treatment: rest from throwing, then a structured rehabilitation program targeting the whole upper-extremity kinetic chain - scapular and core stability and flexor-pronator strengthening - a graded return-to-throwing progression, attention to mechanics, and possibly an orthobiologic such as PRP; many partial tears return to throwing this way. For a complete tear, or a partial tear that fails non-operative care, in a competitive overhead athlete who wants to keep throwing, the operative mainstay is UCL reconstruction, the Tommy John procedure, using a tendon graft - commonly palmaris longus or gracilis - through humeral and ulnar tunnels to recreate the anterior bundle, with docking or figure-of-eight techniques and protection or transposition of the ulnar nerve; rehabilitation and return to throwing take around nine to twelve months or longer. UCL repair, often augmented with an internal brace, is an option for a selected acute proximal or distal avulsion with good tissue, typically in a younger athlete, and allows a faster return. On outcomes, return to play after reconstruction is roughly 80 to 90 percent - a systematic review of adolescents found about 84 percent returned to the same level or higher with low complication and reoperation rates. Given the rising incidence, I would emphasise prevention: pitch-count limits, adequate rest, avoiding year-round single-sport throwing, and optimising mechanics.