A 19-year-old minor league pitcher has noticed a drop in his pitching velocity over the past 3 months. Over just the past 4 weeks, he has noticed mild discomfort at his dominant right medial elbow at the late cocking phase of his throwing but not during follow-through. He denies any history of trauma and mechanical symptoms and has no symptoms unless he is throwing. He has no evidence of neurologic symp- toms. His physical examination demonstrates painless elbow ROM from 0 to 145 degrees on the left and 10 to 145 degrees on the right, with no pain at terminal extension. He is tender over the medial epicondyle and the path of the MCL. Resisted active wrist flexion causes no symptoms, but he has asymmetric laxity on stress testing of the MCL with a positive moving valgus stress test. Neurologic examination demonstrates no focal deficits or abnormalities. Plain x-rays show a well-reduced ulnohumeral articulation without degenerative changes or loose bodies. An axial x-ray shows no posterior ulnohumeral abnormalities.
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What is the most likely diagnosis? What is on the differential diagnosis?▶
What advanced imaging may be helpful?▶
Describe the soft tissue anatomy that creates stability against valgus stress.▶
What are the principal surgical treatment options?Vignette 40: Answer
This patient presents with insufficiency of the MCL of the elbow. This is likely in the form of attritional insufficiency secondary to overuse as a high-level throwing athlete given the lack of trauma. His history and occupation make this diagnosis likely, as does his physical exam pattern of laxity. The moving valgus stress test is believed to be the most sensitive and specific exam for this diagnosis, and it is performed with the patient upright and the shoulder abducted 90 degrees. The elbow is quickly extended from 120 to 30 degrees of flexion while applying a valgus load, which should cause medial elbow pain.140 The differential diagnosis
in such a case must also include medial epicondylitis, which would also present with tenderness at the medial epicondyle but should have pain with resisted wrist flexion but no signs of laxity. Ulnar neuropathy or a sub- luxating ulnar nerve must also be evaluated for. Neuropathy will usually present with complaints of numb- ness and tingling and cold intolerance with hand weakness, and a subluxating nerve will typically rest in the ulnar groove in extension but subluxate anterior to the epicondyle in flexion. Advanced imaging is typically indicated because the diagnosis is sometimes unclear. MRA is now preferred, with the greatest sensitivity and specificity for diagnosing complete and partial tears, and can also help assess for other pathology. (This vignette is primarily for the MCL, but one cannot talk about MCL injuries without evaluating the ipsilateral shoulder, especially assessing for a glenohumeral internal rotation deficit [GIRD]. This discussion should be done to include in the initial physical exam. If GIRD is not corrected, MCL reconstruction will likely fail.)
The medial elbow has dynamic and static soft tissue restraints. The primary dynamic restraint is the flexor pronator mass, especially the flexor carpi ulnaris and FDS. The primary static soft tissue restraint is the MCL, which serves overall as the primary restraint to valgus load, even more so in flexion than exten- sion. Although the MCL is composed of 3 bands (anterior, posterior, and transverse), the anterior is the pri- mary restraint and is reconstructed surgically.140 The anterior band originates on the anteroinferior medial
epicondyle, inserts on the medial ulna at the sublime tubercle, and is most taut in mid-range flexion (30 to 90 degrees).140,141
A complete symptomatic tear in a high-level thrower who is eager to return to sport is typically treated with reconstruction using palmaris longus autograft or hamstring allograft or autograft through bone tun- nels in the medial epicondyle and medial ulna. Every effort is made to create anatomic restoration of the anterior bundle of the MCL. Ulnar nerve decompression is required to access the insertion site, and formal transposition is recommended. There are several acceptable fixation options, but a detailed description of the surgical technique and fixation options is out of the scope of this vignette.
The original Jobe technique for reconstruction required complete release of the flexor pronator mass and ulnar nerve submuscular transposition, which resulted in ulnar nerve complication rates between 20% and 30%. This technique typically had return to sport rates of 60% to 70%. The docking technique described by Altchek142 has become the preferred technique for many surgeons, allowing less invasive single-tunnel place-
ment in the humerus and fine tensioning of the graft. Series using this technique report greater than 90% return to sport and decreased ulnar nerve complications.141
Why Might This Be Tested? The anatomic support of the medial elbow is well known, and insufficiency
of the MCL presents classically in throwing athletes. MCL insufficiency is likely to be encountered by many general, sports medicine, and upper extremity surgeons, and the operative indications, surgical principles, and expected outcomes should be known.
Unlike LCL insufficiency, MCL insufficiency typically presents with a stable elbow that is largely asymptomatic at rest but demonstrates medial elbow pain and decreased throw- ing velocity in throwing athletes. Be aware of the classic physical exam maneuvers for MCL insufficiency. MCL reconstruction with tendon allograft is the preferred technique for athletes who plan to resume throwing, with return-to-sport rates of approximately 90% in most series.