Stress-Distribution Pattern Across the Glenohumeral Joint in Collegiate and Professional Baseball Players: A Computed Tomography Osteoabsorptiometry Study

Abstract

Background: The influence of long-term loading conditions on the articular surfaces of the glenohumeral joint can be determined by measuring stress-distribution patterns. Long-term pitching activity changes the stress distribution across the glenohumeral joint surface; however, the influence of competitive level on stress-distribution patterns remains unclear. Purpose: To use computed tomography (CT) osteoabsorptiometry (CTOAM) to evaluate the distribution of subchondral bone density across the glenohumeral joint in collegiate and professional baseball players as well as to determine the effects of pitching activity on the articular surfaces. Study Design: Descriptive laboratory study. Methods: We evaluated 73 shoulders in 50 baseball players. CT imaging data were obtained from the dominant-side shoulder of 12 professional pitchers (PP group) and 15 professional fielders (PF group). CT imaging data were also obtained from both shoulders of 12 asymptomatic collegiate pitchers (CP group) and 11 collegiate fielders (CF group). The pattern of distribution of subchondral bone density across the articular surfaces of each glenohumeral joint was assessed by CTOAM. As a measure of bone density, the mean Hounsfield units (HU) were obtained for each joint surface, and the absolute values of the dominant shoulder were compared for each group. Results: Stress-distribution patterns over the articular surfaces differed between the dominant and nondominant sides in the CP group as well as between both collegiate groups versus the PP group. In the CP group, the mean HU of the humeral head surface were greater on the nondominant versus dominant side ( P = .035). On the dominant side, the mean HU of the humeral head surface and glenoid were greater in the CP versus the PP group ( P = .001 and .027, respectively). Conclusion: Stress distribution on the articular surface of the glenohumeral joint was affected by pitching ability and competitive level. Our analysis indicates that the traction force on the glenohumeral joint surface might be greater than compression force during pitching. Clinical Relevance: The present findings suggest that pitching activity results in low stress to the articular surfaces of the glenohumeral joint. This supports the notion that mechanical conditions play a crucial role in the etiology of disorders specific to pitching activity.

Computed tomography Osteoabsorptiometry: Review of bone density, mechanical strength of material and clinical application

“…In the CP Group, the average HU of the humeral head surface on the non-dominant side and the dominant side was greater ( p = 0.035). On the dominant side, the average HU of humeral head surface and shoulder glenoid in the CP Group was larger than that in the PP group ( Numaguchi et al, 2021 ).…”

Influence of differences in bone morphology on the distribution patterns of subchondral bone density across the trapeziometacarpal joint

“…Fifth, there is no consensus about the definition of the high-density area. There are various definitions of this area in previous reports 13 – 19 . We selected the upper one-third of HU values as the high-density area according to previous reports 15 , 16 .…”

“…A few studies have shown that stress distributions under physiological loading conditions through a joint are indirectly assessed with the distributions of subchondral bone density that can be measured using CT-OAM 11 , 12 . Previous studies have demonstrated that CT-OAM can potentially be used to evaluate cumulative stress distribution patterns, measuring the distribution patterns of subchondral bone density, indirectly in various joints 13 – 19 . We believe that the analysis of subchondral bone density has the potential to be a useful tool to study alterations in stress distribution through the TMC joint under load.…”

Influence of differences in bone morphology on stress distribution patterns across the trapeziometacarpal joint

“…Previous studies have demonstrated that CT-OAM can potentially be used to evaluate long-term stress distribution patterns in various joints [13][14][15][16][17][18][19] . We believe that the analysis of subchondral bone density offers a useful tool to study alterations in stress distribution through the TMC joint under load.…”