Flexor Tendon Zone II Repair
Authors: Hong Daniel Y. , Strauch Robert J. 
Published: October 2023

Background:
Flexor-tendon injury is a historically challenging problem for orthopaedic surgeons. Much research has been dedicated to finding solutions that offer balance in terms of the strength and ease of the repair versus the rate of complications such as adhesions. The number of core sutures, distance from the tendon edge, and use of an epitendinous stitch have been shown to affect repair strength
1–4
. A number of configurations have been described for the placement of the suture; however, none has been identified as a clear gold standard
5
. This article will highlight the preferred tendon repair technique of the senior author (R.J.S.), the Strickland repair with a simple running epitendinous stitch. Relevant anatomy, indications, operative technique, and postoperative management will be discussed.

Description:
The flexor tendon is typically accessed via extension of the laceration that caused the initial injury. After the neurovascular structures and pulleys are assessed, the tendon is cleaned and prepared for repair. A 3-0 braided nylon suture is utilized for the 4-core strand repair and placed in the Strickland fashion. A 5-0 polypropylene suture is then utilized for the simple running epitendinous stitch.

Alternatives:
Multiple alternative techniques have been described. These vary in the number of core strands, the repair configuration, the suture caliber, and the use of an epitendinous or other suture. Nonoperative treatment is typically reserved for partial flexor-tendon laceration, as complete tendon discontinuity will not heal and requires surgical intervention.

Rationale:
The 4-core strand configuration has been well established to increase the strength of the repair as compared with 2-core strand configurations, while also being easier to accomplish and with less suture burden than other techniques
1
. The presently described technique has excellent repair strength and can allow for early active range of motion, which is critical to reduce the risk of postoperative adhesions and stiffness.

Expected Outcomes:
Excellent outcomes have been demonstrated for primary flexor-tendon repair if performed soon after the injury
1,2,6,7
. Delayed repair may lead to adhesions and poor tendon healing
8
. Early postoperative rehabilitation is vital for success
9
. There are advocates for either active or passive protocols
10–12
. The protocol at our institution is to begin early active place-and-hold therapy at 3 to 5 days postoperatively, which has been shown in the literature to provide improved finger motion as compared with passive-motion therapy
13–16
.

Important Tips:

The proximal end of the tendon may need to be retrieved via a separate incision if it is not accessible through the flexor-tendon sheath.The proximal end of the tendon may be held in place with a 25-gauge needle in order to best place sutures into both ends of the tendon.The epitendinous suture is run around the back wall before the core sutures are tied down, in order to prevent the tendon and repair from bunching up and becoming overly bulky.The entire A4 pulley and the distal A2 pulley can be divided for exposure if necessary.Up to 2 cm of the flexor-tendon sheath can be divided.If there are concomitant digital nerve injuries, repair these after the tendon, in order to avoid damaging the more delicate nerve repair while manipulating the tendon for repair.The most common major complications following tendon repair are formation of adhesions and rerupture.

Acronyms and Abbreviations:

FDS = flexor digitorum superficialisFDP = flexor digitorum profundusMCP = metacarpophalangealPIP = proximal interphalangealDIP = distal interphalangeal