Posterior Ossification of the Shoulder: The Bennett Lesion

Abstract

We report a series of ossific lesions of the posterior inferior glenoid in a group of elite baseball players. We hope to clarify the etiology, diagnosis, and treatment of the Bennett lesion. From August 1985 to August 1991, we identified six professional baseball pitchers and one college pitcher with evidence of ossification of the shoulder on plain radiographs, computed tomography, or magnetic resonance imaging. Arthroscopic examination was performed in all cases. All seven players had identifiable posterior labral injury on arthroscopic examination; six of these seven also had varying degrees of undersurface posterior rotator cuff damage. No anterior tissue damage, anterior instability, or subacromial impingement was noted. No ossification was identified arthroscopically. Intraarticular labral and rotator cuff tears were debrided arthroscopically and patients underwent rehabilitation for 4 to 6 months after surgery. Six of the seven athletes returned to preinjury performance levels; however, one pitcher is no longer playing competitive baseball. The Bennett lesion is an extraarticular posterior ossification associated with posterior labral injury and posterior undersurface rotator cuff damage. It is not, however, a result of traction stresses in the region of the triceps insertion. Recognition is important for identification and treatment of the lesion and associated pathologic damage.

Internal Impingement of the Shoulder

“…Thus, while Bennett proposed that overgrowth of the posteroinferior glenoid represented an osteophytic extension of the glenoid rim itself, Ferrari et al suggested that the calcific changes in the region may instead be due to repetitive traction of the posterior capsule and PIGHL during the extremes of the throwing motion. 27 Other studies have supported these findings as well. 48,60 Greater tuberosity changes are also commonly found on the radiographs of internal impingement patients.…”

“…6 Most subsequent reports have refuted the association between the triceps and the bony exostosis lesion or Bennett lesion, as it is most commonly called. 27, 54 Bennett also described articular-sided fraying of a superficially intact supraspinatus tendon as a typical finding, but he thought that it was related to anterior shoulder pain and not glenoid impingement. 6 In 1992, Walch et al 80 published a landmark article in which 30 athletes were assessed for shoulder pain.…”

Posterior shoulder pain in throwing athletes with a Bennett lesion: Factors that influence throwing pain

“…Several hypotheses have been proposed regarding the mechanisms of this lesion, such as traction on the posterior joint capsule or triceps tendon during the follow-through phase of throwing, posterior impingement of the humeral head on the glenoid in the late-cocking phase, or a wringing action during the acceleration phase. [1][2][3]6,7 In addition, local irritation of the joint capsule and axillary nerve by the bony spur and internal impingement have been suggested as possible causes for how the bony spur induces posterior shoulder pain in throwing. [6][7][8] The pathologic significance of the Bennett lesion is still controversial, and which type of Bennett lesion induces throwing pain is not clear.…”

Estudo do desequilíbrio da força máxima entre os grupos musculares rotadores mediais e rotadores laterais da articulação do ombro, em jogadores da categoria juvenil de beisebol

“…Vários desses autores atribuem ao desequilíbrio de forças entre os grupos musculares, que controlam os movimentos do ombro. Dentre as diferentes fases de movimentos executados acima da cabeça no arremesso, existem duas que são críticas para o aumento da dor no ombro: a fase de preparação para o arremesso ("cocking") e a fase final de desaceleração ("follow-through"), que são descritas por FERRARRI (1994) 10 . A associação de movimentos repetitivos acima da cabeça e erros de treinamento referentes ao gesto esportivo do lançamento, provocam o aparecimento de sintomas e, supostamente, provocam também as acomodações tissulares adaptativas que acarretam a instabilidade glenoumeral.…”