Return to sport testing at 6 months after arthroscopic shoulder stabilization reveals residual strength and functional deficits

Abstract

A good outcome after arthroscopic stabilization for recurrent shoulder instability is often characterized by a successful return to sport while minimizing complications. There is currently no consensus regarding timing or objective criteria for return to sport. The objective of this study is to evaluate the ability of postoperative patients to meet expected goals by using standardized objective evaluations of strength and physical function. Forty-three (10 females, 76.7% male) subjects (mean age, 18.1 ± 3.7 years) who underwent arthroscopic shoulder stabilization surgery (anterior or posterior) from 2016 until 2018 were referred during their postoperative rehabilitation for functional testing at 6 months postoperatively to evaluate their readiness for return to sport. The Closed Kinetic Chain Upper Extremity Stability testand Unilateral Seated Shot Put test were used to assess shoulder function. Posterior rotator cuff activation was evaluated using a repetition to failure technique with 5% body weight at 0° and 90° of abduction with the goal of 90% of nonoperative extremity. Isokinetic strength testing of external rotation (ER) and internal rotation (IR)was evaluated using a Biodex isokinetic dynamometer at angular velocities of 60° and 180° per second, and a passing score was considered achieving 90% of nonoperative shoulder strength at both 60° and 180° per second. All subjects were competitive athletes (20 collegiate, 23 high school). The dominant extremity was the surgical extremity in 22 subjects. Only 5 subjects were able to successfully pass the battery of tests for strength and function. Strength testing revealed that 7 patients achieved 90% of the strength of the nonoperative extremity in both repetitions to failure (23 of 43) and comparative isokinetic testing (7 of 43). More subjects were able to meet IR strength (20 of 43) than ER strength (12 of 43) goals. Functional test goals were more frequently achieved, with 26 of 43 subjects meeting both functional test goals (33 Closed Kinetic Chain Upper Extremity Stability, 34 Unilateral Seated Shot Put). Only 2 subjects were able to achieve strength goals but did not pass functional tests, whereas 21 subjects passed functional tests without meeting strength goals. A substantial number of athletes in our cohort do not meet the expected goals for their operative shoulder in achieving appropriate function and strength, compared with the contralateral shoulder. Functional goals were more often met than strength. IR strength goals were more frequently achieved than ER strength. Strength and functional testing could provide more reliable criteria than arbitrary passage of time for return to play after shoulder stabilization surgery.