Arthroscopic Stabilization in Patients With an Inverted Pear Glenoid

Authors: TS Mologne, MT. Provencher, KA. Menzel, TA. Vachon and CB. Dewing

References: American Journal of Sports Medicine 35:1276-1283 (2007)

Abstract
Background: Recent literature has demonstrated that the success rates of arthroscopic stabilization of glenohumeral instability deteriorate in patients with an anteroinferior glenoid bone deficiency, also known as the "inverted pear" glenoid.

Purpose: This study was conducted to assess the outcomes of arthroscopic stabilization for recurrent anterior shoulder instability in patients with a mean anteroinferior glenoid bone deficiency of 25% (range, 20%–30%).

Study Design: Cohort study; Level of evidence, 3.

Methods: Twenty-one of 23 patients (91% follow-up) undergoing arthroscopic stabilization surgery and noted to have a bony deficiency of the anteroinferior glenoid of 20% to 30% were reviewed at a mean follow-up of 34 months (range, 26–47). The mean age was 25 years (range, 20–34); 2 patients were female and 19 were male. All patients were treated with a primary anterior arthroscopic stabilization using a mean of 3.2 suture anchors (range, 3–4). Eleven patients had a bony Bankart that was incorporated into the repair; 10 had no bone fragment and were considered attritional bone loss. Outcomes were assessed using the Rowe score, the American Shoulder and Elbow Surgeons (ASES) Score, the Single Assessment Numeric Evaluation (SANE), and the Western Ontario Shoulder Instability (WOSI) Index. Findings of recurrent instability and dislocation events were documented.

Results: Two patients (9.5%) experienced symptoms of recurrent subluxation, and 1 (4.8%) sustained a recurrent dislocation that required revision open surgery. The mean postoperative outcomes scores were as follows: SANE = 88.1 (range, 65–100; standard deviation [SD] 9.0); Rowe = 85.2 (range, 55–100; SD 14.1); ASES Score = 93.1 (range, 78–100; SD 5.3); and WOSI Index = 398 (82% of normal; range, 30–1175; SD 264). No patient with a bony fragment experienced a recurrent subluxation or dislocation, and mean outcomes scores for patients with a bony fragment were better than those with no bony fragment (P = .08). No patient required medical discharge from the military for his or her shoulder condition.

Conclusions: Arthroscopic stabilization for recurrent instability, even in the presence of a significant bony defect of the glenoid, can yield a stable shoulder; however, outcomes are not as predictable especially in attritional bone loss cases. Longer-term follow-up is needed to see if these results hold up over time.

Key Words: shoulder instability • shoulder dislocation • shoulder subluxation • glenoid bone loss • inverted pear glenoid • shoulder • arthroscopic shoulder • glenoid fracture • Bankart