The Evaluation of a FDP-to-Volar Plate Zone I Repair Versus Button Repair: An In-Vitro Biomechanics Study
Mohammad Haddara, BEng, MESc, PhD1; Eric C Mitchell, MD2; Joshua A Gillis, MD, FRCSC3; Louis Ferreira, PhD, P Eng1; Nina Suh, MD, FRCSC4
1Western University, London, ON, Canada; 2Western University, Roth | McFarlane Hand and Upper Limb Centre, London, ON, Canada; 3Division of Plastic Surgery, Eastern Health, St John's, NF, Canada; 4Roth McFarlane Hand & Upper Limb Centre, London, ON, Canada
ntroduction: Treatment of zone I flexor digitorum profundus (FDP) lacerations often involve tendon reinsertion into bone via the pullout button technique. Although common, this procedure has led to patient concerns and dissatisfaction; with complications such as contracture and loss of joint range of motion. A study by Al-Qattan et al. in 2010 introduced a technique for treating these injuries through the use of the distal volar plate (VP) as a distally based flap for tendon repair. Biomechanically, the technique was found to not result in joint instability or flexion contracture, though assessment of joint kinematics following the raising of the VP flap are lacking. Therefore, the purpose of this study is to evaluate joint kinematics and tendon work of flexion (WOF) following the proposed flexor digitorum profundus to volar plate (FDP-VP) repair technique relative to a pullout button for zone I flexor tendon injuries.
Materials and Methods: Fourteen digits were tested using an in-vitro active finger motion simulator under three repaired conditions following a simulated zone I avulsion: 1) Button, 2) FDP-VP, and 3) ‘no slack’ FDP-VP (corrected for additional VP length). Outcome metrics included active joint range of motion (ROM), fingertip strength, FDP and flexor digitorum superficialis (FDS) tensile loads, and work of flexion (WOF).
Results: The button and FDP-VP techniques both restored WOF to the intact condition for FDP and FDS. All repairs restored distal interphalangeal joint (DIPJ) ROM and kinematics to the intact condition. Similarly, all repairs restored WOF; however; the ‘no slack’ FDP-VP significantly increased WOF by 10-12% over the simple FDP-VP repair (p<0.05). The button technique had similar fingertip strength to the intact condition, while the FDP-VP repairs significantly reduced peak fingertip strength (p<0.05) from intact, albeit only 1-2N compared to the button repair.
Conclusion: Both the button and FDP-VP techniques restored WOF and ROM to within intact levels with no difference between these repairs in all measured outcome metrics. Thus, based on its initial strength and its equal biomechanical performance compared to the button repair, the FDP-VP technique may be a viable option for treating FDP avulsions.
Back to 2023 Abstracts