Towards A Splint-free Repair
Adjunct Associate Professor Beng-Hai Lim
Centre for Hand and Reconstructive Microsurgery (CHARMS), Paragon Medical Suites and Department of Orthopaedic Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
Post-operative care following a successful flexor tendon repair is dependant on the quality of repair. A strong repair allows for a more aggressive post-operative rehabilitation.
The advantages of an immediate unprotected active mobilization of the hand include improve range of active motion; minimize risk of tendon adhesion, contractures and loss of grip strength. The risk however is tendon rupture.
Biomechanical studies have shown that an unrestricted mobilization of the tendon puts the strain on the site as high as 50N to 120N with flexion against resistance of 500g and 3.5kgf . There is also associate weakening of the tendon at 1 week and this can decrease the strength of the repair to as high as 50%.
The need for a strong repair of at least 200N will probably minimize the risk of rupture if an immediate unprotected mobilization of the hand is encouraged.
This requires a shift in paradigm in our repair techniques. Three specific anchoring points have been identified viz zone 1, 3 and 5. These sites are chosen because it allows for a slightly bulkier anchoring of tendons. The use of a double needle, 2 ‘o’ fibrewire with a single button anchoring at points more than 3 cm away from the lacerated tendon site will allow us to achieve such tendon strength.
A proposed employment of mesenchymal stem cell at the site of repair may be another modality to minimize the weakening of the lacerated tendon ends and maintain the strength of the repair.
A major shift in our repair techniques may pave way for a more robust and sustainable repair. This will allow for a non-patient dependant and a splint free repair. This will further improve the results of tendon repair and allow an earlier functional use of the hand following a flexor tendon injury.