Introduction: Interstitial supraspinatus tears can cause persistent subacromial impingement symptoms. This is the first comparative study to investigate safety and efficacy of Autologous Tenocyte Injection (ATI) compared to corticosteroid injection (CS) for interstitial rotator cuff tears.
Methods: Thirty participants were randomised to receive ATI (n=19) to the interstitial tear or CS (n=11) to the subacromial bursa under ultrasound guidance, in a 2:1 randomisation ratio. Inclusion criteria were duration of symptoms >6 months, magnetic resonance imaging (MRI) confirmed intrasubstance supraspinatus tear, and had previously undergone physiotherapy and at least one CS injection. Of the enrolled cohort, 20 (67%) were male, the mean age was 50.5 years (SD 8.5, range 30-63) and the mean DOS was 21.8 months (SD 12.1, range 7-48). Assessments were undertaken pre-treatment and at 1, 3, 6 and 12 months post-treatment, including the Constant Score, Visual Analogue Pain Scale (VAS), American Shoulder and Elbow Surgeons Shoulder Assessment (ASES) and the Simple Shoulder Test (SST).
Results: No pre-treatment group differences (p>0.05) existed. The ATI group performed significantly better in the Constant Score at 1 (p=0.020, ATI = 81.8, CS = 67.6), 6 (p=0.026, ATI = 84.9, CS = 71.1) and 12 (p=0.024, ATI = 86.5, CS = 65.4) months, and reported better ASES scores at all post-treatment timepoints including 6 (p=0.012, ATI = 88.6, CS = 74.0) and 12 (p<0.01, ATI = 93.3, CS = 62.9) months. The mean ASES scores in the ATI group improved from baseline to 6 and 12 months (14.4 and 19.1 points, respectively), with improvements greater than the MCID (12.0 points). At 12 months, 95% of the ATI cohort reported a PASS (patient acceptable symptom state) in their ASES score. The ATI group reported significant better VAS scores at all post-treatment timepoints, including 6 (p=0.010, ATI = 2.3, CS = 4.2) and 12 (p<0.01, ATI = 1.6, CS = 4.3) months, and reported significantly better SST scores at 3 (p=0.041, ATI = 84.3, CS = 69.7) and 12 (p=0.046, ATI = 90.8, CS = 77.1) months. No injection side effects were observed, though 7 of 11 CS participants withdrew from the trial between 6 and 12 months due to worsening pain and function.
Discussion: This is the first Level 1 study using ATI to treat interstitial supraspinatus tear with chronic impingement syndrome. The preliminary data demonstrate that ATI results in a significant and sustained reduction in pain, and improvement in shoulder function.
Impact and Application to the Field: Non-surgical treatments for interstitial supraspinatus tears can result in persistent and/or recurrent symptoms. This is the first comparative study to demonstrate safety efficacy of ATI compared to CS, as a treatment for these symptomatic interstitial rotator cuff tears.
Conflict of Interest Statement: a funding grant was provided by Orthocell to assist this research.