Review Question - QID 219984

The patient presented with valgus extension overload and obvious posteromedial olecranon osteophyte formation (Figure A) for which he underwent an arthroscopic resection with exuberant olecranon resection resulting in secondary ulnar collateral ligament injury as shown in Figures B and C (Answer 3).

Valgus extension overload, or "pitcher's elbow," is a condition characterized by posteromedial elbow pain related to repetitive microtrauma in throwing athletes. The diagnosis is made clinically with posteromedial elbow pain that worsens with elbow extension, particularly during the deceleration and follow-through phases of pitching, and is due to excessive shear forces on the medial aspect of the olecranon tip and olecranon fossa that causes cartilage injury, osteophyte formation, and eventual loose body formation from fragmentation. First-line treatment is non-operative; however, when this fails, arthroscopic osteophyte resection is often indicated. Given that the ulnar collateral ligament (UCL) can become attenuated with the repetitive strain seen in valgus extension overload, care must be taken to only remove osteophyte and not normal olecranon, as this may result in a loss of bony restraint and further increase stress on the ligament. Multiple cadaveric studies have demonstrated that resection greater than or equal to 9 mm results in ulnar collateral ligament rupture with subsequent applied valgus stress.

Kamineni et al. published a kinematic study on partial posteromedial olecranon resection. The authors included 12 cadaveric elbows with three sequential resections performed in 3-mm steps from 0 mm to 9 mm and found that sequential partial resection of the posteromedial aspect of the olecranon resulted in stepwise increases in valgus angulation with valgus torque. They concluded that bone removal from the olecranon, especially in elite throwing athletes, should be limited to osteophytes, without the removal of normal bone, as doing so may increase strain on the medial collateral ligament.

Kamineni et al. also published a biomechanical study of medial collateral ligament strain resulting from partial posteromedial olecranon resection. The authors used an electromagnetic tracking device to investigate the strain in the anterior bundle of the medial collateral ligament as a function of increasing applied torque and posteromedial resections of the olecranon in seven cadaveric elbows. They found that strain in the anterior bundle of the medial collateral ligament increased with increasing flexion angle, valgus torque, and olecranon resection beyond 3 mm. This led them to conclude that resections of the posteromedial aspect of the olecranon of >3 mm may jeopardize the function of the anterior bundle.

Figure A is a sagittal T2-weighted MR image demonstrating loose bodies in the olecranon fossa (arrowheads) and posteromedial olecranon osteophyte formation consistent with valgus extension overload. Figures B and C are sequential T2-weighted coronal MRI cuts showing abnormal increased fluid signal and fiber discontinuity along the course of the ulnar collateral ligament related to UCL tearing, as demonstrated in Illustration A with red arrows.

Incorrect Answers:
Answer 1: Accelerated return-to-throwing after arthroscopic osteophyte resection is unlikely to be the main cause of this patient's new valgus instability and new UCL tear shown on MRI in Figures B and C.
Answer 2: Though there is some fluid signal within the common extensors consistent with lateral epicondylitis, there is nothing in the history to suggest concurrent lateral-sided instability, which would be rare with valgus extension overload in a pitcher.
Answer 4: There was nothing in the presenting history or imaging to suggest an initial UCL tear, the dominant structure of which is the anterior band of the anterior bundle, not the posterior bundle.
Answer 5: There is no evidence of aberrant anatomy or anatomic variant on the patient's included imaging.