Sonographic and Elastographic Findings after Arthroscopic Rotator Cuff Repair: a Comparison with Clinical Results.

Objective: We assessed the relationship between early postoperative clinical outcomes of arthroscopic rotator cuff repair (ARCR) and observations obtained by post-surgical ultrasound (US) and strain elastography (SE) of repaired supraspinatus tendons (SSTs).Methods: This retrospective study included 42 cases in which the patient underwent ARCR followed by postop-erative US and SE. The Korean Shoulder Scoring (KSS) system was used to assess preoperative and postoper-ative conditions. The thickness of the repaired SST and subdeltoid fluid was measured by US. SE scores were classified into four grades (1 to 4) according to elasticity of repaired SST. In addition, SE scores were divided into two groups: soft (SE scores of 1 and 2) and hard (SE scores of 3 and 4). The relationship between clinical outcomes and US parameters and SE scores was deter-mined by KSS.Results: Postoperative SE scores observed by two readers correlated significantly with function (p = 0.021 and p = 0.021, respectively) and muscle strength (p = 0.008 and p = 0.015, respectively). SE scores were significantly correlated with a difference value of muscle strength of KSS scores (p = 0.002 and p = 0.014). In a comparison of hard and soft groups of repaired SSTs, function (p = 0.008 and p = 0.010, respectively) and muscle strength (p = 0.002 and p = 0.014, respectively) in postoperative KSS scores were statistically higher in the hard SE scores than the soft SE scores. The differ-ence value of function (p = 0.021 and p = 0.021,) and muscle strength (p = 0.008 and p = 0.015) of KSS scores was significantly higher in the hard SE scores.Conclusions: Postoperative SE scores of repaired tendons correlated significantly with muscle strength and function after ARCR. Postoperative US images including thickness of repaired tendon and subdeltoid fluid did not correlate with clinical outcome.Advances in knowledge: SE evaluations of repaired SST may provide important information about postoperative muscle strength and function.