Predictors of Outcomes after Arthroscopic Double-row Rotator Cuff Repair in 155 Cases: A Propensity Score Weighted Analysis of Knotted versus Knotless Self-reinforcing Repair Techniques at a Minimum of 2 Years

OBJECTIVES: The purpose of this study was to analyze predictors of clinical outcomes of knotted versus knotless double-row self-reinforcing rotator cuff repairs of full-thickness rotator cuff tears with propensity score matching. METHODS: Patients with arthroscopic repair of full-thickness rotator cuff tears involving the supraspinatus tendon using either a knotted or knotless linked, self-reinforcing double-row technique were included in the study. Preoperative subjective evaluation was performed using the ASES and SF-12 PCS scores. After a minimum two-year follow-up period, ASES and SF-12 PCS scores were collected again along with the SANE score, the QuickDASH score, and patient satisfaction. All data were collected prospectively and retrospectively reviewed. Postoperative ASES and SF-12 PCS scores were then modeled using inverse propensity score weighting in a multiple linear regression model (MLR) with multiple imputations. Age, sex, baseline ASES score, length of follow-up, number of anchors, worker’s compensation, previous cuff repair, and double-row repair technique (knotted or knotless) were the covariates used in this model. RESULTS: 155 shoulders in 151 patients (109 men, 42 women; mean age at time of surgery 59±10 years) were eligible for inclusion. Outcomes data were available for 130 of 148 shoulders (87.8%) after exclusion of seven shoulders (4.5%) that underwent revision rotator cuff repair before final follow up (n=33/39 in the knotted group [84.6%]; n=97/109 [88.9%] in the knotless group).The mean follow-up was 2.9 years (range, 2.0-5.4 years). Overall, postoperative outcomes scores were significantly improved when compared to preoperative baselines (p<0.05), with a median postoperative ASES score of 97 for the entire cohort. Our model showed that previous rotator cuff repair had a significant negative effect on postoperative ASES (β = -12.7, p<0.001) and SF-12 PCS scores (β = -5.0, p = 0.036). A workers’ compensation claim (β = -10.6, p = 0.007) also had a significant negative effect on postoperative ASES scores. Higher baseline ASES score (β = +0.14, p = 0.025) positively influenced ASES outcomes. Use of a knotless technique also had a positive effect on postoperative scores (β = +2.5, p = 0.235). Age, gender, the length of follow-up and the numbers of anchors did not influence the outcomes (Table 1). CONCLUSION: Excellent clinical outcomes can be achieved a minimum of two years following arthroscopic repair of full-thickness rotator cuff tears using either the knotted or knotless linked double-row technique. Negative predictors of outcome include low preoperative ASES score, previous rotator cuff repair, and a workers’ compensation claim. Knotless double-row rotator cuff repair had a non-significantly positive effect on the postoperative ASES score compared to the knotted double-row suture bridge technique.