The size of a Hill-Sachs lesion in anterior shoulder instability doesn’t appear to affect functional outcomes, according to a new study.
The authors of “Association Between Excessive Joint Laxity and a Wider Hill-Sachs Lesion in Anterior Shoulder Instability,” wrote, “Excessive general joint laxity, a negative prognostic factor in joint instability, has not been studied to determine its relationship with bipolar bone loss in anterior shoulder instability.”
In their study published on October 25, 2021, in The American Journal of Sports Medicine, they investigated the characteristics of bipolar bone defects in the presence of excessive joint laxity and examined how that may or may not affect clinical outcomes based on the on-track/off-track theory.
They hypothesized that patients with excessive joint laxity might have less bipolar bone defects than those without excessive joint laxity. But there would be no difference in clinical outcomes.
The Korean based research team enrolled 81 patients who had been treated with an arthroscopic Bankart repair. Thirty-three of the patients had excessive joint laxity and 48 didn’t. Excess joint laxity was defined as a score of 4 or greater.
The study authors collected data regarding bone lesions using preoperative 3D computed tomography. They performed an arthroscopic procedure that insets the posterior shoulder capsule and infraspinatus tendon into the Hill-Sachs defect, converting the intra-articular location of the defect to an extra-articular one—otherwise known as a remplissage procedure—for patients with off-track or positive engagement test in borderline on-track lesions.
The researchers measured patient recurrence rates, Subjective Shoulder Value, Rower score, University of California Los Angeles shoulder score, active range of motion, and the sports/recreation activity level.
Overall, there was no significant difference found in the glenoid bone defect between the two groups (14.1%, excessive laxity group; 14.4% no excessive laxity group). Additionally, 39.4% of the excessive laxity group had off-track lesions compared to 14.6% in the no excessive laxity group (p = .011).
The mean Hill-Sachs interval to glenoid track ratio was 83.1% in the excessive laxity group and 75.2% in the no excessive laxity group (p = .021).
Additional remplissage procedures were needed more in the excessive laxity group (48.5% vs. 16.7%; p = .002). Despite this, there were no significant difference in the shoulder functional scores and recurrence rates between the two groups.
“Patients with anterior shoulder instability and excessive joint laxity had significantly wider Hill-Sachs lesions and more off-track lesions than did those with normal joint laxity despite the lack of a significant difference in the glenoid bone defect. However, these differences in the Hill-Sachs lesion were not related to differences in the functional outcomes between the groups,” the authors wrote.
The authors involved in the study included Joon-Ryul Lim, M.D., Ph.D., Hyung-Min Lee, M.D. and Yong-Min Chuch, M.D., all of Arthroscopy and Joint Research Institute, Yonsei University College of Medicine, Severance Hospital, Seoul, Republic of Korea. Hwan-Mo Lee, M.D., Ph.D., of Yonsei University College of Medicine, Severance Hospital, Seoul, Republic of Korea, also contributed to the study.
