Biomechanics and Motion Analysis

Repair and Rehabilitation of Flexor Tendon Injury

Principal Investigator: Peter C. Amadio, M.D.
Project Coordinator: Chunfeng Zhao, M.D. — zhao.chunfeng@mayo.edu
Funding Source: NIH AR44391

The overall goal of this project is to improve the results of tendon repair through the development of therapies that affect the tendon gliding surface.  The underlying hypothesis continues to be that improvements in the results of flexor tendon repair can be obtained by methods that minimize friction on the gliding surfaces of tendon and sheath.

In the previous funding period we explored means to further improve gliding and reduce adhesions by physicochemical and pharmacological means.  These studies have shown that adhesions can be dramatically reduced with an engineered tendon surface coating containing lubricin, a lubricating glycoprotein ubiquitous in articular cartilage, but in some cases the healing process in lubricin treated tendons is delayed.  In this funding period, therefore, we propose to investigate methods to preserve the beneficial effects of our novel tendon surface modification while improving intrinsic tendon healing through a tissue engineering approach.

We have recently developed a novel means of increasing the strength of the tendon repair through the use of an interpositional collagen patch seeded with bone marrow-derived stromal cells (BMSC).  Our central hypothesis is that this tissue engineered patch will improve the speed and strength of tendon healing without adversely affecting the beneficial effects of lubricin-augmented repair on tendon gliding and adhesions.  This potential “two pronged” attack could allow for adhesion free tendon repair, without gapping or rupture.  In addition, such an approach would provide benefits in clinical situations where immediate rehabilitation with early motion is impossible, such as in cases of replantation or other complex trauma, or in small children or other uncooperative patients.  To test this hypothesis, we have developed three specific aims:

• Aim 1:  To investigate the healing of flexor tendons following the incorporation of a BMSC seeded, cytokine augmented collagen patch into the repair site in a canine model in vitro.

  Hypothesis:   That the BMSC seeded, cytokine augmented patch will enhance intrinsic tendon healing in vitro, as demonstrated by higher tensile strength and improved histological appearance.

• Aim 2:  To investigate the effects a BMSC tendon patch combined with surface modification on flexor tendon repair in a canine model in vivo.

  Hypothesis:   That the combination of a tendon patch and topical anti-adhesion surface treatment will result in improved intrinsic tendon healing in vivo without adversely affecting tendon gliding ability.

• Aim 3: To investigate the effect of surface modification and a BMSC patch on animals subjected to a postponed tendon rehabilitation protocol.

  Hypothesis:   That the combination of a tendon patch and topical anti-adhesion treatment will result in improved final strength and gliding in the context of postponed post-operative rehabilitation, compared to the results of postponed rehabilitation without these therapies.