[Management of zone 1 flexor digitorum profundus tendon injuries]

The Transosseous Internal Four Strand Technique: A New All-Inside Technique for Zone 1 Flexor Tendon Repairs

BACKGROUND

Multiple techniques for the repair of flexor tendon injuries in zone 1 have been proposed over time. While pull-out suture techniques and bone anchor seem to be stronger than internal suture techniques, they are associated with a higher complication rate. We therefore developed an alternative internal suture repair with similar biomechanical stability to those of pull-out sutures and bone anchors.

METHODS

Twenty porcine distal phalanges and deep flexor tendons were randomized to 2 groups of 10 each. The tendons were transsected at the level of the distal interphalangeal joint. In group 1, repairs were performed with a well-established intraosseous suture repair and in group 2 with our new multistrand technique. The repairs were biomechanically tested with linear distraction until failure.

RESULTS

We recorded a significantly higher 2-mm gap force (2GF)-and thus higher stability-of the repairs in group 1 in comparison to group 2. With a 2GF of more than 50 N, our suture technique allows for a modern early active motion rehabilitation protocol. Breakage of the suture construct occurred at random places in the repair in both groups. No pull-outs were noted.

CONCLUSIONS

This study presents a strong transosseous multistrand repair technique for flexor tendon repair in zone 1 that is simple and fast to perform and should have enough strength to withstand early active motion rehabilitation.

Mini All-Suture Anchors for Repairing the Central Slip of the Extensor Tendon at the Proximal Interphalangeal Joint: A Biomechanical Investigation

PURPOSE

This study evaluated 1.0-mm mini suture anchors for repairing the central slip of the extensor mechanism at the proximal interphalangeal joint. Studies have reported a requirement for central slip fixation to withstand 15 N during postoperative rehabilitation exercises and 59 N during forceful contraction.

METHODS

Index and middle fingers from 10 matched pairs of cadaveric hands were prepared with 1.0-mm mini suture anchors with 2-0 sutures or threaded with 2-0 sutures through a bone tunnel (BTP). In total, 10 index fingers from unmatched hands were prepared with suture anchors and fixed to the extensor tendons to evaluate the tendon/suture interface response. Each distal phalanx was secured to a servohydraulic testing machine, and ramped tensile loads were applied to suture or tendon until failure.

RESULTS

All anchors for the all-suture bone tests failed because of pullout from the bone (Mean failure force = 52.5+/-17.3 N). Three anchors from the tendon-suture pull out test failed by pullout from the bone and seven failed at the tendon/suture interface (Mean failure force = 49.0+/-10.1 N).

CONCLUSIONS

The 1.0-mm mini suture anchor provides enough strength for early short-arc motion, but it may not be adequate for forceful contraction in the early postoperative rehabilitation stage.

CLINICAL RELEVANCE

The site of fixation, the type of anchor, and the type of suture used are key factors to consider for early range of motion, after surgery.

Case 247: Jersey Finger of the Fifth Finger

History A 34-year-old man without underlying medical conditions came to the emergency department for evaluation of persistent pain over the volar portion of his right fifth finger after a fall during a football match 3 days before. At physical examination, the injured finger was swollen and purple. Passive and active flexion of the proximal and distal interphalangeal joints were compromised, without interphalangeal instability. Radiography was performed in the emergency department, and the patient was released with a diagnosis of a fifth digit sprain. After the senior radiologist (V.M.C.) reviewed the radiographs, the patient was called back for assessment with ultrasonography (US) on the same day. US was performed with an Aplio 500 unit (Toshiba Medical Systems, Tokyo, Japan) using a multifrequency linear array 7.2-18.0-MHz PLT-1204BX transducer focused at the level of the flexor tendon. The patient was sitting in front of the examiner, with the hand lying palm up on the examination bed. No abnormality was observed during color Doppler US.