Bipolar Bone Loss in Male Athletes With Traumatic Anterior Shoulder Instability: An Evaluation Using a New Scoring System

Abstract

Background:The combination of a glenoid defect and a Hill-Sachs lesion in a shoulder with anterior instability has recently been termed “bipolar bone loss,” but the prevalence and influence of this condition on postoperative recurrence after arthroscopic Bankart repair are still unclear.Purpose:To investigate bipolar bone loss in male athletes using a new scoring system and to evaluate its efficacy by comparing it with the glenoid track concept.Study Design:Case-control study; Level of evidence, 3.Methods:The sizes of both lesions were evaluated retrospectively in 80 male athletes (85 shoulders) using computed tomography. The glenoid defects and the length, width, and depth of the Hill-Sachs lesions were classified into 5 size categories and were allocated scores from “0” for no defect to “4” for the largest defect. Patients were then classified into 5 classes according to the total score for both lesions: class 1, 0-1 point; class 2, 2 points; class 3, 3 points; class 4, 4 points; and class 5, ≥5 points. The prevalence of bipolar bone loss and postoperative recurrence rates for patients with at least 2 years of follow-up were compared among the classes. The recurrence rate for each class was also compared between shoulders with an off-track lesion and shoulders with an on-track lesion as well as among 3 sporting categories: rugby, American football, and other sports.Results:Based on the combination of glenoid defect size and Hill-Sachs lesion length, the postoperative recurrence rate was 0% for shoulders in class 1, 12.5% for class 2, 33.3% for class 3, 28.6% for class 4, and 31.3% for class 5, while the recurrence rates were 0%, 16.7%, 28.6%, 27.3%, and 31.6%, respectively, for the combination of glenoid defect size and Hill-Sachs lesion width and 0%, 8.3%, 26.7%, 28.6%, and 35.3%, respectively, for the combination of glenoid defect size and Hill-Sachs lesion depth. Postoperative recurrence was frequently recognized regardless of the presence of off-track Hill-Sachs lesions. No recurrence was recognized in class 1 shoulders among rugby players, in classes 1 and 2 among American football players, and in classes 1 through 3 among other athletes based on the combination of glenoid defect size and Hill-Sachs lesion size.Conclusion:Our scoring system for bipolar bone loss was useful to evaluate the influence on postoperative recurrence in male athletes. The postoperative recurrence rate was influenced by the extent of bipolar bone loss and the sporting category regardless of the presence of off-track lesions.

Changes of Bipolar Bone Defect Size After Arthroscopic Bankart Repair for Traumatic Anterior Shoulder Instability: Evaluation Using a Scoring System and Influence on Postoperative Recurrence

“…A lesion was classified as off-track if the HSI was larger than the GT, while it was on-track if the HSI was smaller than the GT. 7…”

“…After these parameters were obtained, the sizes of the bipolar bone defects were investigated, and each glenoid defect and each Hill-Sachs lesion was classified into 5 categories according to bone defect size with reference to the criteria of Nakagawa et al 7,12 (scores from 0 [no defect] to 4 [very large defect]) (Table 3). To assess the combined size of the glenoid defect and the Hill-Sachs lesion, we summed the scores for both lesions, and the patients were classified into 9 categories based on the total score (0-8) according to our modification of our earlier scoring system.…”

“…Nakagawa et al 12 investigated the relationship between glenoid defects and Hill-Sachs lesions in shoulders with traumatic anterior instability, reporting that coexistence of both lesions was a possible risk factor for recurrent instability after arthroscopic Bankart repair. In addition, Nakagawa et al 7 recently proposed a scoring system for bipolar bone defects. They reported that postoperative recurrence was influenced by the preoperative bipolar bone defect sizes and the sporting category regardless of the presence or absence of an off-track lesion.…”

Avaliação da trilha da glenoide no ombro

“…Inicialmente essas lesões eram avaliadas individualmente mas, durante o século XXI, essa visão mudou e começou-se a entender essas lesões como bipolares e integradas [31][32][33][34][35][36][37][38][39]…”

“…As lesões de Hill-Sachs, que antes estavam dentro da trilha, apresentam-se fora da mesma nos casos em que a trilha da glenoide diminui após o carregamento das forças, o que pode levar a escolhas terapêuticas equivocadas e falhas cirúrgicas. Conclui-se que não se deve tomar decisões com base em avaliações que não contemplaram as forças articulares, principalmente em relação a lesões de Hill-Sachs que estão dentro da trilha, mas próximas ao limite de contato39,67 .A linha de pesquisa sobre a trilha da glenoide vem se desenvolvendo há pouco mais de uma década. Yamamoto et al32 e Omori et al41 realizaram estudos com o objetivo de encontrar uma medida padrão para guiar a conduta terapêutica da instabilidade glenoumeral anterior.…”