Transosseous Multiple Finger Flexor Tendon Pulley Reconstruction
Authors: Simon Michael , Lutter Christoph , Tischer Thomas , Schöffl Volker 
Published: May 2022

Background: Closed finger flexor tendon pulley injuries occur most frequently in rock climbing but also during other heavy finger strength work or exercises. While single pulley injuries receive a conservative therapy, multiple pulley injuries often require a surgical repair, as otherwise they will lead to contracture and loss of range of motion and functionality. While established surgical techniques, which use bone encircling tendon graft techniques, were found to produce osteonecrosis of the phalanx, our new transosseous technique avoids this problem. Indications: All triple pulley injuries (A2,3,4) (grade-4b injuries) and double pulley injuries (A2,3 or A3,4) (grade-4a injuries) are indicated, if the injury is older than 10 days at the point of therapy start or the flexor tendons bowstringing is either not redressable in the ultrasound or extended. Also, grade-4a injuries are indicated, if a secondary contracture starts to build. Technique Description: Standard palmar-sided incision, followed by debridement of the tendon sheath, pulley flap, and, if applicable, scare tissue in between the flexor tendons and the bone is performed. Wire-guided 3.0-mm drill holes at the base phalanx at the level of the former distal portion of the A2 pulley are completed. Passing of the palmaris longus tendon through the drill hole and interlacing it as a “loop and a half” follows. Distal continuation through lacing the transplant through the remaining rims of the former pulleys and the flexor tendon sheath is then performed. Securing the repair after tendon gliding control to itself is completed. Postsurgically, the splint is immobilized for 2 weeks, followed by the use of a thermoplastic pulley support ring for 4 weeks with active mobilization. Results: No complications occurred during or after the surgery. In few cases, a restricted range of motion in the proximal interphalangeal (PIP) joint of the respective finger of up to 3 to 5 grade occurred. One patient, who had a presurgical PIP extension deficit of 30°, which was released during the surgery, developed over time again a 20° extension deficit. The functional outcome score ranged between good and excellent, with one case being only satisfactory. The sport-specific outcome score was either good or excellent for all patients, with one patient with contracture where it was satisfactory. No osteonecrosis of the phalanx was recorded. Discussion: For multiple pulley ruptures, various surgical techniques are described. We favored a modified “loop and a half” technique with a distal continuation to the A3 pulley. This combines the advantages of the “loop and a half” technique, as the strongest, and the Weilby repair, as the most functional repair. We recently noticed some cases with osseous necrosis of the phalanx following this repair, likely due to the high pressure of the circulation of the tendon graft onto the bone and its blood vessels. Therefore, we have modified our procedure into a transosseous repair, which is presented in this article. This approach was first evaluated in a cadaver study to exclude a potential risk of osseous failure (fracture) during stress caused by the drill hole. After ruling out this risk, the transosseous technique became our standard approach, as it combines the advantages of the “loop and a half” technique with those of the Weilby repair and decreases the pressure onto the dorsal cortex of the fingers base phalanx and thus the risk of osteonecrosis.