A systematic temporal assessment of changes in tendon stiffness following rotator cuff repair

A systematic temporal assessment of changes in tendon stiffness following rotator cuff repair

REVIEWED BY Deborah Carmody, AFASA | ASA SIG: Musculoskeletal

REFERENCE | Authors: Lisa Hackett, Ryan S Ting, Patrick H Lam, George AC Murrell

WHY THE STUDY WAS PERFORMED

Rotator cuff disorders are a common cause of shoulder pain and discomfort, and surgical repair of the rotator cuff is one of the most common upper limb surgeries performed. There is a high incidence of retear after surgical repair of the rotator cuff, prompting the need to understand the healing process and material changes in the tendon.

Shear-wave elastography (SWE) can be used to quantify tissue stiffness. Bone is a stiff structure and has high shear-wave velocity and low shear-wave displacement. Tissues such as muscle bellies or adipose tissues are less stiff and have low shear-wave velocity and high shear-wave displacement. Tendon stiffness is in between bone and adipose tissue. The stiffness of uninjured tendons should be greater than those of tendinopathic tendons.

The paper aimed to evaluate whether there were changes in time (over one year) in supraspinatus tendons post arthroscopic rotator cuff repair in terms of:

• stiffness (using SWE)

• thickness

• the relationship between tendon stiffness and thickness

HOW THE STUDY WAS PERFORMED

The supraspinatus tendon of 50 participants who had surgically repaired rotator cuff tendons (single-row inverted mattress arthroscopic repairs) was sonographically assessed using longaxis B-mode imaging and acoustic radiation force imaging (ARFI) SWE (at three regions: adjacent to, 3 mm medial and 6 mm medial to the tendon footprint, all 2 mm posterior to the long head of biceps brachii tendon). Participants were assessed at six time points by a single sonographer: 1, 6, 12, 24 and 52 weeks, postoperatively.

WHAT THE STUDY FOUND

The study found several significant findings:

• The stiffness of the supraspinatus tendon increased in the lateral tendon 24 weeks following primary arthroscopic rotator cuff repair before stiffness increased at the medial tendon and continued to improve out to 52 weeks post-op.

• The repaired tendon became 11% thinner in the first 6 weeks post-surgery and that tendons that were less stiff 1 week postoperatively were more likely to be thinner 6 weeks postoperatively. This finding that tendon thickness decreased from 1 to 6 weeks postoperatively was consistent with our hypothesis that the repaired supraspinatus tendon takes 6 weeks to heal to the bone, before becoming stiffer over time.

Evidence of rotator cuff tendon healing on postoperative ultrasound is characterised by increased echogenicity with increased fibrillar pattern and echotexture.

RELEVANCE TO CLINICAL PRACTICE

Understanding the changes in tendon stiffness and thickness can aid in patient management and rehabilitation planning. The observation that tendons may stretch and thin out in the initial 6 weeks post-surgery highlights the importance of careful postoperative monitoring and early intervention if necessary.