Lateral elbow painful snap secondary to a continuous plica synovialis in the radiocapitellar joint: Case report.

Lateral elbow painful snapping is a rare, debilitating condition, often misdiagnosed for lateral epicondylitis due to its unfamiliarity or lack of definitive imaging tool to diagnose it. We report a case of a 25-year-old male with a 4-month history of painful snapping during terminal elbow flexion, triggered by weightlifting and push-ups, without prior trauma. Clinical examination showed bilateral elbow hyperextension of 10°, with visible/palpable snapping and pain at 110°-120° flexion, occurring in both supinated and pronated forearm positions, only when initiated from full extension. MRI revealed a small triangular soft tissue fold with effusion in the radio-capitellar joint. Arthroscopy identified a thick, whitish, continuous band of soft tissue spanning the radio-capitellar joint from anterior to posterior, with a free inner end and lateral capsular attachment. Cartilage erosions were noted on the proximal and outer radial head (contiguous portion). Arthroscopic resection of the interposing tissue resolved symptoms immediately post-operatively. Histopathology confirmed features consistent with a synovial plica. Literature suggests that the dynamic nature of this condition and clinicians' unfamiliarity often lead to missed diagnoses on plain MRI. Unlike the commonly reported posterolateral plica, this case involved a rare continuous band causing snapping in both pronated and supinated positions. This report underscores the importance of recognizing atypical presentations of lateral elbow snapping and highlights the efficacy of early arthroscopic excision for symptom relief and cartilage preservation, offering a valuable diagnostic and therapeutic approach for this rare condition.