A Suture Method for Collateral Ligaments of the Finger Proximal Interphalangeal Joint: A Cadaver Study.

Purpose: In a cadaveric model, a comparison was made of the strength of a suture method for collateral ligaments (the N method) with that of simple sutures using suture anchors for the repair of collateral ligaments in the proximal interphalangeal joint.

Methods: We obtained 72 fingers from 18 upper limbs of fresh-frozen cadavers and compared the left and right sides of the same specimens. In experiment 1, we examined the rupture strength and rupture sites of intact collateral ligaments in 24 fingers. In experiment 2, we compared the rupture strength and failure modes of the N method (three locking sutures) with those of simple sutures (S group) on 32 fingers. In experiment 3, we examined the rupture strength and failure modes between the N method with three locking sutures (N3 group) and the N method with two locking sutures (N2 group) on 16 fingers. All the experiments involved mechanical testing by applying lateral stress to the collateral ligaments at a rate of 1 mm/s using testing equipment.

Results: In Experiment 1, the mean rupture strength of intact collateral ligaments was 80.6 ± 27.5 N. Proximal tears were the most common rupture sites. In Experiment 2, the mean rupture strength was significantly higher in the N group (46.3 ± 19.2 N) than in the S group (24.1 ± 12.7 N). In the N group, suture breakage occurred more frequently than in the S group, whereas in the S group, there was a higher incidence of suture cut out. In Experiment 3, the N3 and N2 groups exhibited nearly identical rupture strength values.

Conclusions: This study showed that the N method had better rupture strength than the simple suture method following finger collateral ligament repair.

Clinical relevance: The outcome provides useful information for informing the choice of suture method in clinical practice.