22 Flexor Tendon Repair in Zone 2: Managing Complications

Gwendolyn van Strien

Abstract

Therapists, like surgeons, make choices regarding the details of each patient’s rehabilitation program to get the best possible outcome. For a rehabilitation program after flexor tendon repair, the choices made by the therapist are based initially on information from the hand surgeon, including mechanism of injury, zone of repair, type of suture material and suture technique used, and pulley status, and then other issues are factored in, related to the work of flexion (WOF), pain, and patient adherence. The aim of this chapter is to propose that early active motion approaches that are patient-centered or individualized rather than protocolled may lead to better flexor tendon repair outcomes.

Wong et al1 have given us a renewed perspective on healing of a repaired flexor tendon and its surrounding tissue (ST). These researchers observed that collagen production starts in the ST about day 3, with the tendon following about a week later, catching up with the ST around day 21. This early healing of the ST and sheath before the tendon translates to ST adhesions which limits repaired tendon glide within the first 3 weeks of injury. These observations coupled with the use of stronger suture materials and repair techniques (4+ strand repairs) suggest that the tendon needs to start moving actively within the first 3 to 5 days.

22.2 Complications

22.2.1 Adhesions versus Ruptures

Adhesions and ruptures are both failed results since both will need secondary surgery. Tenolysis is a more common complication than rupture after flexor tendon repair, with re-repair having better outcomes than tenolysis.² The rate of tendon rupture is not much different whether early passive motion (4%) or early active motion (EAM) (5%) is used. Yet the difference in tendon glide/excursion achieved with EAM (9%) is significantly greater than that achieved with early passive motion (6%), suggesting when possible, EAM should be the chosen program.³

22.2.2 Bowstringing

Stronger repair techniques are more bulky, consequently pulley venting is being done so not to interfere with proximal and distal tendon glide/excursion. Pulleys were once thought to be a biomechanical necessity, we know now that this is not entirely true as observations with sonography showed only minimal bowstringing 1 year after pulley venting.⁴ Surgeon communication of details including the number of repair strands, pulley(s) status vented or repaired, and how well the repair was actively or passively gliding intraoperatively are essential for the hand therapist to develop an individualized postoperative plan.

22.3 Prevention of Complications

22.3.1 Early Active Motion

Work of Flexion and Tendon Glide

An early active motion (EAM) program initiates active tendon excursion within the first 7 days after repair. The objective of safe EAM is to use the least amount of force to achieve enough tendon glide to minimize adhesions. Under normal conditions as fingers actively flex, resistance or work of flexion (WOF) is encountered.⁵ The WOF is influenced by edema, stiffness, and position of the wrist and fingers, tight pulleys, all important considerations to avoid repair rupture.

Edema and WOF

Edema management is key as EAM starts within the first postoperative week, and edema increases WOF. Wu and Tang⁶ estimated that the tissues on the volar aspect of the finger plus edema contribute 20 to 25% of total WOF.

●Compression wraps are often used to control edema; however, a single study found that the WOF increased with the application of these wraps.⁷ Consider compression wrap removal during exercise to possibly lower the WOF.

Stiff Joints and WOF

After repair, stiff finger joints and friction from tendon swelling and repair bulkiness (internal WOF) account for about 25 to 30% of total WOF.⁶ This resistance is reduced when passive range of motion of the interphalangeal joints is done prior to active motion exercises.⁶

●Passive range of motion always before active motion.

●Active motion beyond what has been achieved passively puts the repair at risk.

Wrist Position and WOF

WOF for an intact tendon increases significantly (flexor digitorum superficialis [FDS] more than flexor digitorum profundus [FDP]) with the wrist positioned in flexion when the fingers are flexed (Kleinert splint position). However, WOF during finger flexion can be lowered for both tendons if the wrist is positioned in neutral or slight extension.8 The Manchester short splint, which allows the wrist to move freely, was used with EAM and four-strand FDP repairs with no increase in tendon ruptures and fewer proximal interphalangeal (PIP) joint contractures.⁹

●To minimize risk of repair rupture in the postoperative cast and the dorsal protective splint, position the wrist in slight extension, never flexion.

●To lessen repair risk, fabricate the Manchester short splint to restrict wrist extension at 45 degrees and advise patients not to simultaneously flex wrist and fingers.⁹

Finger Position and WOF

During active finger flexion, the passive tension imposed by the dorsal extrinsic extensor tendons accounts for about 15% of total WOF.⁶ As discussed, positioning the wrist in extension affects passive tension from the long extensors. Equally as important is that WOF by FDP and FDS can lower further, depending on the position of the metacarpophalangeal (MCP) joints. Flexor tendon WOF was lowest at 15-degree MCP joint position; however, when MCP joint angles were greater than 45 degrees, WOF substantially increased in both tendons.⁸

●Since this chapter advocates individualized treatment, the author recommends that one can choose the 15-degree position when the surgeon is confident about the repair and the therapist is experienced in using an EAM approach. A position between 30 and 45 degrees is best practice for less experienced therapists or when the surgeon feels the repair needs a more protected approach.

●Some patients can benefit from more MCP joint flexion (30–45 degrees) to make PIP and distal interphalangeal (DIP) extension easier and prevent flexion contractures. Keep in mind that full extension is rarely achieved in the first 7 to 10 days postoperatively but, when safe, strive for full IP extension as early as possible.

●Later during the initial 4 postoperative weeks, the angle of MCP joint flexion can always be adjusted to further reduce WOF and achieve optimal tendon glide.

Pulleys and WOF

After tendon repair, pulleys contribute about 30% of total WOF with active finger flexion.⁶ WOF can be reduced by venting of the pulleys and/or resecting one slip of the FDS tendon.

Another important consideration is that by allowing too much active composite finger flexion early on, the rate of tendon ruptures has been shown to increase.⁶ There were less tendon ruptures when active composite finger flexion was limited to one-third compared to two-thirds, and full flexion. In the same study, after pulley resection, the increased rate of rupture seen with two-thirds to full active composite finger flexion was reduced.

●To avoid potentially harmful WOF, the surgeon is advised to communicate key details of the surgery to the hand therapist, such as repair bulk, pulley status, vented or not, quality of intraoperative tendon glide through the pulleys.

●Do not encourage active full finger flexion until 3 to 4 weeks after repair. A one-third to a one-half fist active composite finger flexion requires less WOF and permits enough tendon glide to discourage adhesions.

22.4 Effective Exercising—Tips and Tricks to Improve Outcomes

22.4.1 Move from the DIP and Not from the PIP

Strickland¹⁰ reported that after repair, FDP excursion was decreased by 65%, while FDS excursion was decreased by only 10%. Clinically, this loss of FDP glide results in less DIP joint flexion as tendon excursion is redistributed to hyperflex the MCP joint, especially in the ulnar digits. To identify how well a zone 1 or 2 FDP repair is gliding, it is important to calculate total active motion by excluding the MCP joint measurement altogether, using only measurements of PIP and DIP joint motion (Fig. 22‑1). The cause of limited FDP glide can be attributed to tightness of the A5 pulley usually due to repair bulk, or the repair getting caught as the two FDS slips at the decussation narrow during PIP flexion.¹¹

●Best practice is for the surgeon to communicate when the location of the FDP repair is near the FDS decussation (when slip of FDS is not resected) so that the therapist knows to avoid FDP trapping exercises, such as a straight fist/PIP joint flexion, and will instead advise “DIP flexion first” exercises.

●Surgeon communication regarding intraoperative observation of FDP glide at the A5 pulley is helpful so that the therapist can prescribe the exercise that is most effective for FDP tendon glide.

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Complications: What They Do to the Patient Debunking Complex Regional Pain Syndrome/Sudeck/Reflex Sympathetic Dystrophy Management of Complications in the Treatment of Fingertip Injuries Management of Complications Following Open Reduction and Plate Fixation of Distal Radius Fractures Treatment of Complications after Scapholunate Ligament Repair Management of Complications of Extensor Tendon Surgery

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