Single-Row vs Double-Row Repair Re-Tears
Strong evidence supports lower re-tear rates after double row repair compared to single row vertical mattress repair when evaluating for both partial and full thickness retears after primary repair; however, when evaluating the data for only full thickness retears, limited evidence does not support lower re-tear rates after double row primary repair.

Rationale
Eight high quality randomized controlled trials (RCTs) utilized magnetic resonance imaging (MRI) reported the re-tear rates after single row versus double row repair in patients with full thickness rotator cuff tears. (Barber 2016, Burks 2009, Franceschi 2016, Franceschi 2007, Koh 2011, Lapner 2012, Ma 2012, Carbonel 2012). 

When the re-tear rates include both partial and full thickness tears, a meta-analysis of the pooled data from these eight RCTs identified the relative risk (RR = 0.58 (0.43-0.78)) of re-tear is significantly lower after double row repair compared to single row repair for full thickness rotator cuff tears.  Thus, there is strong evidence that supports lower re-tear rates (partial and full thickness) after double row repair compared to single row vertical mattress repair for full thickness rotator cuff tears.

However, when re-tears are defined as full thickness only, the relative risk (RR = 0.71 (0.45-1.11)) is 0.71 with a wider confidence interval (0.45 – 1.11) which indicates limited evidence to support lower risk of re-tear (Full thickness) after double row compared to single row repairs.

Risks and Harms of Implementing this Recommendation
There is no harm to patients by implementing this recommendation.  However, partial and full thickness re-tear rates may be higher after single vertical mattress repair compared to double row in patients with full thickness rotator cuff tears.  The clinical significance is unknown.

Future Research
Future research should be performed to evaluate for failure rates on imaging and reoperation rates between single row compared to double row repair for full thickness rotator cuff tears.  Research also needs to be done to better identify the clinical significance of a partial thickness re-tear after arthroscopic rotator cuff repair.