Posteromedial Elbow Impingement: MRI Findings in Overhead Throwing Athletes and Results of Arthroscopic Treatment (SS-26)

Abstract

Posteromedial elbow pain as a result of impingement has a reproducible pattern of pathology on MRI in throwing athletes. Arthroscopic debridement, olecranon spur excision, and loose body excision if present allows return to throwing sports, and excellent subjective and objective results. Posteromedial elbow pain in throwing athletes may be the result of valgus extension overlead and UCL insufficiency or due to posteromedial impingement due synovitis or olecranon spurring. An MRI with or without intra-articular contrast is the gold standard imaging modality. To date, no pattern of MRI findings has been reported in the setting of clinical posteromedial elbow impingement. The purpose of this study was to define the MRI pattern and assess the results of arthroscopic treatment. Over an 8 year period, a total of 10 throwing athletes were identified retrospectively, who were diagnosed with posteromedial elbow impingement who had an MRI, and who failed non-operative treatment and ultimately required arthroscopy. Any patients with UCL insufficiency were excluded from the study. Those with a clinical diagnosis of posteromedial elbow impingement underwent an MRI examination using either a standard noncontrast protocol, or a direct MR arthrographic protocol. All MRIs were acquired at 1.5 tesla using a dedicated extremity receiver coil with the patient's affected arm extended while prone on the scanner in a ‘superman' position. All studies included edema sensitive T2 weighted fast spin echo fat suppressed sequences in 3 planes, while the direct MR arthrographic studies included high resolution T1 weighted spin echo fat suppressed images in at least two planes. MRIs were reviewed by a fellowship trained musculoskeletal radiologist blinded to clinical history other than age and gender. Arthroscopic treatment included debridement of posteromedial synovitis, loose body (if present) excision, and excision of any olecranon spur. All patients underwent a physical examination and completion of the Andrews-Carson scale with a minimum follow-up of 12 months (range: 12 - 73). All patients were male with an average age of 21.2 (range: 15 - 34). The dominant arm (right = 9) was affected in all patients. The average length of symptoms prior to surgery was 9 months (range: 5 - 24). At MRI, a reproducible pattern of pathology was noted. All patients had pathology recorded at the articular surfaces of the posterior trochlea and the anterior, medial olecranon, ranging from abnormal edema like signal in the hyaline cartilage (grade 1 chondrosis) to partial thickness cartilage defects and subjacent, subchondral bone marrow edema (grade 2 or 3 chondrosis). Additional MRI findings included joint effusion, synovitis within the posteromedial recess, marginal osteophytes at the trochlea and olecranon, soft tissue edema about the distal, medial triceps insertion, ulnar collateral ligament hypertrophy, and flexor/pronator tendon origin strain. Findings at surgery included posteromedial synovitis and olecranon spurring in all patients, and loose bodies in 3 patients. Based on the Andrews-Carson scale, the subjective and objective outcome was considered excellent in 8 patients and good in 2. Posteromedial elbow pain as a result of impingement has a reproducible pattern of pathology on MRI in throwing athletes. Arthroscopic debridement, olecranon spur excision, and loose body excision if present allows return to throwing sports, and excellent subjective and objective results.