Summary

This is the first Level 1 prospective randomised controlled trial demonstrating that Autologous Tenocyte Injection resulted in a significantly better and sustained reduction in pain and improvement in shoulder function, compared with corticosteroid injection, as treatment for tendinopathy and interstitial tears of the rotator cuff.

Abstract

Introduction

Interstitial supraspinatus tears can cause persistent subacromial impingement symptoms despite non operative treatment. Preclinical and clinical studies of Autologous Tenocyte Injection (ATI) have shown that cultured tenocytes can synthesise extracellular matrix and facilitate healing of damaged tendon tissue. Therefore, ATI may be an effective treatment for interstitial cuff tears. This study presents the results from the first randomised controlled study to investigate the safety and efficacy of ATI compared to corticosteroid injection (CS) as treatment for tendinopathy and interstitial tears of the rotator cuff.

Methods

Eligible participants were randomised to receive ATI to the interstitial tear or CS to the subacromial bursa in a 2:1 ratio, under ultrasound guidance. 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. Assessments were undertaken pre-treatment and at 1, 3, 6 and 12 months post-treatment, including the Constant Score, Visual Analogue Pain Scale (VAS) and American Shoulder and Elbow Surgeons Assessment (ASES). 3 T MRI was performed at baseline, 6 and 12 months post treatment.

Results

Thirty participants were enrolled (19 randomised to ATI and 11 to CS). The mean age of enrolled participants was 50.5 years (SD 8.5, range 30.2-63.3) and there were 10 female and 20 male participants. Mean duration of shoulder symptoms was 21.8 months (SD 12.1, range 7-48). 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, reported better (p<0.05) VAS scores at all post-treatment timepoints and reported better ASES scores at all 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) and were greater than the MCID (12.0 points). At 12 months post treatment, 95% of ATI participants reported a PASS (patient acceptable symptom state) in their ASES score. Overall, 7 of 11 participants in the CS group withdrew from the trial between 6 and 12 months due to worsening shoulder pain and function.

Conclusions

This study demonstrated that ATI resulted in a significantly better and sustained reduction in pain, and improvement in shoulder function, compared with CS. ATI is an emerging non-surgical treatment to promote tendon healing and repair. This is the first Level 1 study using ATI to treat interstitial supraspinatus tears with chronic impingement syndrome.