This study evaluates the effect of synergistic wrist motion vs. passive digital motion alone on adhesion formation after repair of 80 percent partial flexor digitorum profundus tendon lacerations in a canine model. Sixty-six dogs were randomized to two post-repair rehabilitation programs. Two ipsilateral FDP tendons were lacerated followed by a repair using a modified Kessler suture with 5-0 Ticron and a 6-0 nylon epitenon running suture. An equal number of dogs were sacrificed at one, three, and six weeks post repair. Adhesion formation was graded grossly, and adhesion breaking strength was mechanically tested. Tendon repair strength was then assessed to failure. The investigators found that the synergestic group overall had a lower adhesion grade and a lower adhesion breaking strength at three and six weeks, but an overall increased incidence of gap formation. The adhesion breaking strength was no different between the groups at one-week post tendon repair. Ultimately, there were an equal number of tendon ruptures and equal ultimate tendon breaking strength despite an increased incidence of gap formation in the synergistic motion group.
Considering this study is specifically aimed at partial tendon repairs in the canine model, it may not be applicable to human tendon surgery, especially with complete lacerations. However, this study suggests that synergistic wrist motion may diminish tendon adhesions possibly via increased tendon excursion. Increased gap formation in the synergistic motion group does suggest increased tension at the wrist repair site. This was tolerated in this partial tendon laceration study since the intact portion of the tendon prevented complete dissociation. Gap formation has previously been shown to increase adhesions and tendon ruptures, and this may not be tolerated in a complete lacerations. The increased gap formation in the synergistic motion group did not ultimately lead to increased rupture rate or difference in ultimate breaking strength.
Journal of Bone and Joint Surgery