Mechanical loading assists tendon regeneration following Autologous Tenocyte Implantation (ATI)

Most conservative treatments for chronic tendinopathies only provide temporary relief from pain and inflammation, but do not improve tendon structure and biomechanics. ATI injections help to re-form the collagen matrix and this process is enhanced with optimal mechanical loading. The challenge is to replicate this load stimulus in human patients via appropriate rehabilitation exercises. With the safety and efficacy of this novel cell therapy now established for patients, what is the role of exercise loading in promoting optimal patient outcomes following cell injection?

Clinical practitioners often emphasise the importance of an active rehabilitation program, either in isolation or in combination with an injection. This is because the healing process following tendon injury is complex, whereby mechanical and chemical factors work together. A direct link between tenocytes and the extra-cellular matrix allows the cells to sense and respond to mechanical stimuli to promote tissue repair and remodelling via a process termed ‘mechanotransduction’.

Patients who have been diagnosed with chronic, end-stage lateral epicondyle tendinopathy (LET), with pain and disability having persisted for at least 6 months, will undergo an initial biopsy of healthy tenocytes that are developed and re-implanted into the degenerated tendon. Patients will rest the affected limb for 1 week and will then be assigned to one of two mechanical loading groups. Group A will wear a wrist immobilisation splint for 6 weeks and be restricted to light stretching and gripping activity, and will refrain from vigorous activity. Group B will attend physical therapy sessions twice per week for 6 weeks to undertake progressive exercise (mechanical) loading and will perform prescribed home exercises daily.

All participants will attend follow-up clinical assessments at 6 weeks, as well as at 3, 6 and 12 months post-injection. These assessments will include the Patient-Reported Tennis Elbow Evaluation (PRTEE), the Visual Analogue Scale for pain (VAS), and the 36-item Short Form Health Survey (SF-36). Clinical global improvement (CGI) will also be determined and recorded on a 7-point Likert scale. Two functional assessments will be administered at the same time points, including pain-free grip strength using a hand held dynamometer, and maximal isometric wrist extension strength using a dynamometer.

Professor Ackland and his colleagues anticipates this research will provide a rationale for how therapeutic forearm exercises can be employed for LET as well as allowing the development of  best-practice rehabilitation guidelines for ATI.

Collaborator/s

  • Winthrop Professor MH Zheng, Clinical Professor AW Wang, Assoc Professor J R Ebert at The University of Western Australia