Cadaveric Comparison of Work of Flexion Following Flexor Tendon Repair: Knotted Versus Knotless Techniques

Few prior studies have compared work of flexion of digital flexor tendons repaired with barbed suture to those performed with conventional knotted techniques. The available evidence is mixed, with one study indicating no difference between the techniques and another showing increased work of flexion with knotless techniques. This study aimed to bolster the current body of literature by comparing work of flexion and strength of digital flexor tendon repairs using knotted and knotless techniques.

Two knotted and 2 knotless techniques for flexor tendon repair were assessed. Each repair was tested in 12 cadaveric flexor digitorum profundus (FDP) tendons. Work of flexion prior to repair was determined. FDP tendons were lacerated and repaired using 3-0 braided/monofilament or 2-0 barbed suture. Work of flexion measurements was repeated. FDP tendons were removed from the hand, and load to 2-mm gap and failure were recorded. One-way analysis of variance and t tests were used for statistical analysis.

Overall, knotless repairs demonstrated greater increases in work of flexion than knotted repairs. There were significant differences in work of flexion by individual technique, with one knotless technique performing similarly to the knotted techniques, while the other performed more poorly. There was no difference in load to 2-mm gap between knotted and knotless techniques, but knotless techniques had lower load to failure.

Some knotless techniques for digital flexor tendon repair may perform similarly to knotted techniques in the immediate postoperative period. Further research is required to determine the effects of knotless techniques on tendon healing and rehabilitation.