Giovanni Di Giacomo1, Petar Golijanin2, George Sanchez3, Matthew T Provencher4. 1. Department of Orthopaedic Surgery, Concordia Hospital for Special Surgery, Rome, Italy. 2. Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, U.S.A. 3. Sports Medicine Service, Massachusetts General Hospital, Boston, Massachusetts, U.S.A. 4. Sports Medicine Service, Massachusetts General Hospital, Boston, Massachusetts, U.S.A.. Electronic address: MattProvencher@gmail.com.
Abstract
PURPOSE: To identify the relation between the Hill-Sachs (H-S) angle and arm position at the time of the initial dislocation, and to see if this correlates with the glenoid track. METHODS: A total of 102 patients (89 male patients, 87.2%), with a mean age of 32 years (range, 17 to 38 years), were divided into 2 groups, abduction (ABD) and adduction (ADD), dependent on the position of the arm at the time of the instability event. All patients were evaluated with bilateral computed tomography scans (3-dimensional) to define the H-S position on the glenoid track and to measure the H-S angle. One-way analysis of variance was used to compare the H-S angle between the 2 groups. RESULTS: Dislocation occurred in ABD in 45 patients (44.1%) and in ADD in 57 (55.9%). The H-S angle was 32.4° ± 4.7° in the ABD group versus 16.1° ± 2.9° in the ADD group. All patients' injuries were "on-track" glenoid injuries in both groups. CONCLUSIONS: This study identified a difference in the H-S angle relative to arm position at the time of initial dislocation. Patients whose injury occurred in the ABD position showed a higher H-S angle, leading to an increased risk of engagement, because the long axis of the H-S lesion is parallel to the glenoid in a position of function. Thus arm position at the time of the initial instability event may be a risk factor for engagement and higher risk of recurrence. LEVEL OF EVIDENCE: Level IV, prognostic case series.
PURPOSE: To identify the relation between the Hill-Sachs (H-S) angle and arm position at the time of the initial dislocation, and to see if this correlates with the glenoid track. METHODS: A total of 102 patients (89 male patients, 87.2%), with a mean age of 32 years (range, 17 to 38 years), were divided into 2 groups, abduction (ABD) and adduction (ADD), dependent on the position of the arm at the time of the instability event. All patients were evaluated with bilateral computed tomography scans (3-dimensional) to define the H-S position on the glenoid track and to measure the H-S angle. One-way analysis of variance was used to compare the H-S angle between the 2 groups. RESULTS: Dislocation occurred in ABD in 45 patients (44.1%) and in ADD in 57 (55.9%). The H-S angle was 32.4° ± 4.7° in the ABD group versus 16.1° ± 2.9° in the ADD group. All patients' injuries were "on-track" glenoid injuries in both groups. CONCLUSIONS: This study identified a difference in the H-S angle relative to arm position at the time of initial dislocation. Patients whose injury occurred in the ABD position showed a higher H-S angle, leading to an increased risk of engagement, because the long axis of the H-S lesion is parallel to the glenoid in a position of function. Thus arm position at the time of the initial instability event may be a risk factor for engagement and higher risk of recurrence. LEVEL OF EVIDENCE: Level IV, prognostic case series.
Authors: Yara Younan; Philip K Wong; Spero Karas; Monica Umpierrez; Felix Gonzalez; Jean Jose; Adam Daniel Singer Journal: Skeletal Radiol Date: 2017-06-08 Impact factor: 2.199
Authors: Matthew L Vopat; Christina A Hermanns; Kaare S Midtgaard; Jordan Baker; Reed G Coda; Sana G Cheema; Armin Tarakemeh; Liam Peebles; Bryan G Vopat; Matthew T Provencher Journal: Orthop J Sports Med Date: 2021-06-03