An Evaluation of the Clinical and Anatomic Predictors of Outcomes at a Minimum of 2 yrs Following the Latarjet Procedure for Recurrent Anterior Shoulder Instability with Glenoid Bone Loss

OBJECTIVES: Although the Latarjet procedure for the treatment of recurrent shoulder instability is highly successful, reasons for failure are often unclear. The purpose of our study was to evaluate clinical and anatomic characteristics that were predictive of continued instability or poor outcomes following the Latarjet procedure. METHODS: In this IRB approved study, patients who underwent open coracoid Latarjet procedures for anteroinferior instability with glenoid bone loss (>20%) prior to October of 2012 were included. Anatomic measurements of coracoid size (anteroposterior surface area, maximal coracoid width), conjoint and subscapularis tendon widths, estimated glenoid defect surface area, Hill-Sach's Interval, and projected postoperative glenoid track engagement were obtained from preoperative cross-sectional imaging. When the projected glenoid track was smaller than the Hill-Sach's interval, the lesion was determined to be outside-&-engaged compared to inside-&-non-engaged. Patient reported subjective data that was prospectively collected and retrospectively reviewed included patient satisfaction, instability events, SANE score, ASES score, DASH score, and SF-12 PCS. Patients that progressed to another shoulder surgery not related to instability were considered complications and patients that continued to experience dislocations or who underwent revision instability surgeries were considered failures. RESULTS: Thirty-nine shoulders in 39 patients (34 men, 5 women) with a mean age of 26 (range 16-43) were included at a mean follow-up was 3.3 years (2- 7.9 years). There were 25 out of 39 that had prior stabilization surgery and 6 workman's compensation claims. One patient was revised due to broken hardware at 2 months and one because of coracoid nonunion at 18 months. One patient experienced postsurgical adhesive capsulitis treated surgically at a year. All subjective outcome scores significantly improved (p<.05) and a 9 out of 10 median satisfaction score was achieved at final follow-up. Patients with moderate pre-operative pain (VAS ≥3) negatively correlated with post-operative SF-12 physical component scores (rho=0.445, p=0.043). Five patients reported recurrent self-reducible dislocations, while 1 other reported subjective subluxation events. Four of the six workman's compensation claims failed due to continued instability. Although statistical significance was not achieved, patients requiring revision surgery for coracoid nonunion and those with continued instability were more likely to demonstrate outside-&-engaged glenoid tracks (p=0.06). CONCLUSION: The Latarjet procedure for recurrent shoulder instability due to glenoid bone loss reliably improves patient reported functional outcomes and leads to high levels of patient satisfaction. Workman's compensation claims were highly associated with continued instability and patients with higher preoperative pain levels were associated with inferior functional outcomes. Although anatomic variations in coracoid size relative to the amount of glenoid bone loss or projected postoperative glenoid track engagement were not found to correlate with patient reported outcomes or risk of recurrent instability, a novel quantitative approach for assessing bipolar bone loss is described that may be prove useful in the future study of the Latarjet and similar glenoid augmentation procedures.