Determining the Patient Acceptable Symptom State (PASS) for Shoulder Strength After Subscapularis Arthroscopic Repair and Evaluating the Preoperative Predictors for PASS Achievement.

Background: Restoring shoulder strength after arthroscopic rotator cuff repair (ARCR) is critical, but there is limited understanding as to what patients consider satisfactory postoperative strength.

Purpose: To determine the Patient Acceptable Symptom State (PASS) values for the Constant score strength parameter and internal rotation (IR) strength in patients who underwent ARCR for rotator cuff tears involving the subscapularis (SSC) muscle and evaluate for associations between preoperative and intraoperative patient characteristics with PASS achievement.

Study design: Case-control study; Level of evidence, 3.

Methods: A retrospective analysis was conducted on prospectively collected data for 278 patients with an SSC tear (isolated or combined) who underwent ARCR and had minimum 2-year follow-up data. Functional outcomes (patient-reported outcomes, range of motion, Constant strength, and IR strength) were assessed preoperatively and at the latest follow-up. The overall, male, and female PASS values for postoperative strength measures were evaluated using receiver operating characteristic analysis. Correlation and logistic regression analyses were used to evaluate the relationship between preoperative variables and PASS achievement for Constant and IR strengths.

Results: The mean follow-up time was 72.8 months. The overall, male, and female PASS values were 9.9 lb (4.5 kg), 14.5 lb (6.6 kg), and 8.5 lb (3.9 kg), respectively, for Constant strength and 15.2 lb (6.9 kg), 20.7 lb (9.4 kg), and 12.1 lb (5.5 kg), respectively, for IR strength. Older age, high fatty infiltration of the SSC tendon (Goutallier grades 3 and 4), and failure of SSC healing correlated negatively with PASS attainment for the strength measures. High fatty infiltration of the supraspinatus and infraspinatus muscles correlated negatively with Constant strength. Decreased coracohumeral distance (CHD) and larger SSC tears correlated negatively with achieving PASS for IR strength. Workers' compensation, high supraspinatus and SSC fatty infiltration, and the use of knotted suture anchors were predictors of not achieving the overall Constant strength PASS, while lower SSC fatty infiltration and high CHD were predictors of achieving the overall IR strength PASS.

Conclusion: This study established the PASS values for Constant and IR strengths for patients after ARCR involving the SSC tendon. Workers' compensation, high supraspinatus and SSC fatty infiltration, and the use of knotted suture anchors were predictors of not achieving the overall Constant strength PASS, while lower SSC fatty infiltration and high CHD were predictors of achieving the overall IR strength PASS.