Do Hyperlaxity, Sex, and Number of Dislocations Have an Impact on the Characteristics of Patients With Chronic Anterior Shoulder Instability?

Background: Chronic anterior shoulder instability affects young, athletic patients linked to activities involving external rotation (ER) and abduction. Some intrinsic patient characteristics may influence clinical presentation and bony lesions. Purpose: To analyze the association between sex, hyperlaxity, and number of dislocations in a cohort of patients with chronic anterior instability. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Between January 2022 and January 2025, patients >15 years of age with chronic anterior shoulder instability who had not been operated on were included in a cohort. Clinical data evaluated included age, sex, hyperlaxity (combined ER and internal rotation [IR] hyperlaxity), and subjective assessment of the shoulder. Regarding the number of dislocations, 4 groups were formed in this cohort: subluxation (ie, partial loss of contact between the humeral head and the glenoid, n = 10), 1 dislocation (ie, complete loss of contact between the humeral head and the glenoid, n = 20), 2 to 3 dislocations (n = 36), and >3 dislocations (n = 34). Bony lesions were assessed by radiographs and computed tomography scan using a semiautomatic method for humeral bone loss (HBL; size, volume, and location) and glenoid bone loss (GBL; percentage of bone loss). Results: In this cohort of 100 patients, 86% of patients had GBL and 83% had HBL. Although there were fewer women (n = 25) in the cohort than men (n = 75) ( P = .01), women more frequently exhibited multidirectional (ER + IR) hyperlaxity (56% for women vs 36% for men; P = .04), narrower glenoid cavities (23.5 vs 26 mm; P < .001) and less GBL (10% for women vs 13% for men; P = .04). Hyperlax patients (n = 41) had smaller bipolar bone lesions than nonhyperlax patients (n = 59): GBL (8% vs 12%; P = .02), Hill-Sachs lesion length (26.7 ± 6.6 mm vs 30.4 ± 9.4 mm; P = .03), Hill-Sachs width (13.0 ± 4.2 mm vs 16.5 ± 5.5 mm; P = .045), and Hill-Sachs volume (2924 ± 2177 vs 5023 ± 4396 mm 3 ; P = .04). In the >3 dislocations group, HBL was larger (length: 32 mm, P = .045; width: 17 mm, P < .001), with a greater volume (5409 mm 3 ; P = .008), deeper (2.4 mm; P = .01), and with a specific location close to 12 o'clock in 3-dimensional analysis. Conclusion: This predominantly male cohort with chronic anterior instability demonstrated that women had narrower glenoid cavities and smaller glenoid bony lesions than men and were more often hyperlax than men. Hyperlax patients, regardless of sex, had smaller bipolar bony lesions, while the number of dislocations increased the size and severity of the HBL. Studies with larger patient samples are needed to confirm these results.