Computed tomography analysis of osteophyte distribution in the throwing elbows of professional baseball players

Posteromedial olecranon impingement is a common elbow disorder in professional baseball players that results from repetitive valgus extension overload during throwing. Osteophyte formation is a hallmark of this condition. However, its anatomical distribution and progression remain unclear. This study aimed to characterize the distribution of osteophytes in the elbows of professional baseball players using computed tomography (CT) and to evaluate the relationship between osteophyte location and player age.

We retrospectively reviewed the CT images of 38 consecutive symptomatic professional baseball players, including 26 pitchers, one catcher, and 11 fielders. All players presented with throwing-related elbow symptoms between 2012 and 2024 and underwent CT scanning of the throwing elbow. Osteophytes were assessed at 14 anatomical sites spanning the ulnohumeral and radiocapitellar joints. Bone projections ≥2 mm from the bone surface were classified as osteophytes. Player age and playing position were compared between elbows with and without osteophytes at each site.

The medial border of the trochlea and the medial aspect of the olecranon were the most frequently involved sites (both 97.4%), followed by the olecranon tip and the coronoid process (both 84.2%). Bidirectional correspondence was observed between the medial border of the trochlea and the medial aspect of the olecranon; osteophytes at one site were always accompanied by the other. In contrast, a unidirectional relationship was noted between the humeral fossae (olecranon and coronoid) and the opposing ulnar processes (olecranon and coronoid); osteophytes on the humeral side always coexisted with those on the ulnar side, but not vice versa. Significantly higher age was observed in players with osteophytes at the lateral olecranon fossa (P = .0215) and the coronoid fossa (P = .0366), whereas no age-related differences were found on the ulnar side. Playing position (pitcher vs. nonpitcher) showed no significant association with osteophyte prevalence at these sites.

This study provides CT-based data on osteophyte distribution in the throwing elbows of professional baseball players. Osteophytes were frequently observed on the ulnar side and were associated with humeral-sided osteophytes in selected regions. Higher age was associated with osteophytes at the lateral olecranon fossa and coronoid fossa, whereas no age-related differences were observed on the ulnar side. These findings may improve understanding of CT-based osteophyte morphology in throwing elbows and may assist diagnostic assessment and surgical planning in professional baseball players.