PREDICTORS OF BONE DEFICIT IN SHOULDER INSTABILITY: THE LUXE COHORT STUDY, A LARGE INCLUSIVE PROSPECTIVE STUDY

Recurrent anterior traumatic shoulder instability is related to progressive bone loss on both the humeral and glenoid side. Recurrence of anterior shoulder instability after stabilization surgery is estimated to be around 35%. The severity of bone loss is known to be one of the principal prognostic factors for treatment success. Identification of risk factors of larger bone deficit may help to identify patients at risk. The purpose of this study is to identify modifiable risk factors that will help us counsel patients on habit modification and thus possibly help decrease recurrence of shoulder instability after stabilization surgery. Since 2010, all patients undergoing surgical treatment for recurrent shoulder instability are included in a vast inclusive prospective study cohort : the LUXE study. Patients were all recruited from Montreal's Sacred-Heart Hospital. All patients with complete demographic data and good quality computed tomography (CT) scans were included. Bone loss was measured using the validated Glenoid Track method, shoulder lesions being identified as “on-track” or “off-track” prior to arthroscopic surgery. Analysis of variance (ANOVA) and Pearson correlation statistical tests were used to correlate the Glenoid Track bone loss measurement method with multiple variables such as patient age, gender, BMI, the mean number of shoulder dislocations reported prior to surgery, alcohol and tobacco consumption, epilepsy, the Beighton score and the shoulder Instability Severity Index Score (ISIS). A total of 204 patients met inclusion criteria (161 male, 43 female) with a mean age of 29 years (range 16–52 years). The mean number of dislocations prior to surgery was 14 (range 2–150). Patient BMI was of 25 on average (range 16–41). A quarter (25%) of patients were smokers and a total of 47% reported alcohol consumption over the recommendations issued by Health Canada. Epilepsy was the cause of instability in 6% of patients. Off-track shoulder lesions were identified in 43% of shoulders and significant glenoid bone deficit, meaning 25% or more of the glenoid diameter, was seen in 19% of cases. Male gender, smoking, drinking alcohol, epilepsy, the number of dislocations and older age were all risk factors for greater bone loss at presentation. This study has shown us mutilple modifiable risk factors of increased bone loss in recurrent shoulder instability patients. Canadian shoulder surgeons should work closely with primary care physicians who are seeing patients with traumatic shoulder dislocations. Furthermore, patients should be educated on how smoking and drinking are related to worse outcomes to their shoulder anatomy. They should also be oriented younger and earlier than a mean of 14 shoulder dislocations for surgical stabilization to prevent progression of damage to their shoulder. Future studies with the LUXE cohort will possibly identify more patient risk factors and different measurement methods of glenoid and humeral bone loss that will help us better predict failure of surgical stabilization.