Risk Factors for Revision of Posterior Shoulder Stabilization in Throwing Athletes

Abstract

Revision posterior shoulder stabilization has been shown to have inferior outcomes when compared to primary surgery. However, risk factors for revision surgery and patient reported outcomes in throwing athletes have not been reported. The purpose of this study was to evaluate the risk factors and patient reported outcomes in throwing athletes undergoing revision posterior stabilization for unidirectional posterior shoulder instability. One hundred throwing athletes (112 shoulders) who underwent arthroscopic posterior labral repair were reviewed at 2-year minimum follow-up. Patients who failed surgical intervention and underwent revision posterior labral surgery were compared to a control group of patients who did not undergo revision. Demographics including age, gender, contact sport participation, level of sport, length of follow-up, and return to sport were compared. American Shoulder and Elbow Surgeons (ASES) and Kerlan Jobe Orthopaedic Clinic (KJOC) Overhead Athlete scores were collected via online surveys and were available for 70 patients. Subjective stability, pain, strength, range of motion (ROM), and perceived effectiveness of surgery were also collected. MRI parameters of glenoid bone version, cartilage version, labrum version, bone width, labrum width, glenoid labrum version and width weight as well as rotator cuff status were also compared. Nine throwers failed primary surgery and required revision posterior stabilization (8.2%) at an average of 2.8 years postoperatively (range 6 – 55 months). Average follow-up was 65 months in the revision group and 38 months in the non-revision group. There was a significantly higher proportion of females in the revision group (44.5% vs 20.8%, p = 0.04). There was no significant difference between the revision and non-revision group in terms of average age (20.1 years vs 19.1 years, p = 0.27), proportion of contact athletes (22.2% vs 43.6%, p = 0.11), or presence of a rotator cuff tear (0% vs 5.9%, p = 0.24). In the revision group, 83% of patients were high school and 17% were college athletes, whereas in the non-revision group, level of participation was 78% high school, 13.5% college, and 2.7% professional, and 5.4% recreational. No statistical difference was seen in MRI measurements of glenoid bone version (9 degrees vs 8.1 degrees, p = 0.31), cartilage version (9.5 degrees vs 8.2 degrees, p = 0.23), labrum version (10.9 degrees vs 10.1 degrees, p = 0.35), labrum version weight (0.26 vs 2.29, p = 0.33), bone width (24.3 mm vs 25.2 mm, p = 0.16), labrum width (29.9 mm vs 28.9 mm, p = 0.27), or labrum width weight (0.19 vs 0.19, p = 0.47). Patients in the revision group had similar preoperative (37.2 vs 47.2, p = 0.15) and postoperative (73.3 vs 81.6, p = 0.45) and difference in (36.3 vs 33.1, p = 0.86) in ASES scores compared to the non-revision group. No significant difference was found in preoperative (32.9 vs 31.9, p = 0.93), postoperative (53.7 vs 50.6, p = 0.87), or change (16.8 vs 20.9, p = 0.74) in KJOC scores between the revision and non-revision groups. There was also no significant difference in subjective postoperative stability (5.2 vs 5, p = 0.92). Pain scores (out of 10) were not significantly different preoperatively (7.7 vs 7.0, p = 0.26), postoperatively (2.6 vs 3.4, p = 0.64), or the change in pain scores (5.2 vs 4.6, p = 0.78). The proportion of patients with perceived full strength (17% vs 46%, p = 0.21), full ROM (17% vs 36%, p = 0.65), and who believed the surgery was worthwhile (85% vs 87.5%, p = 1) were also similar. A smaller percentage of patients in the revision group were able to return to sport compared to the non-revision (33% vs 80.6%, p = 0.03), though the percentage able to return to the same level of participation was not significantly different (17% vs 27.4%, p = 1) (Table 1). Revision rate of arthroscopic posterior shoulder stabilization in throwing athletes was 8.2% at average 2.8 years post-operatively. Females were at a higher risk for revision surgery. Patients in the revision group also had a lower rate of return to sport compared to the control group. Age, rotator cuff injury, glenoid version, nor glenoid width were risk factors for revision. This data is useful to counsel throwers undergoing arthroscopic posterior capsulolabral repair. Throwers may be more likely to require revision surgery than other athletes, and those who undergo revision surgery may have worse outcomes compared to primary surgery.