Creator: Dr. Mohammed hutaif
Published: 2026-04-12T14:33:58.144020+00:00

INTRODUCTION TO FLEXOR TENOLYSIS

Flexor tenolysis is one of the most demanding and unpredictable procedures in hand surgery. Following primary flexor tendon repair or free tendon grafting, the biological process of tendon healing inevitably involves both intrinsic and extrinsic pathways. When the extrinsic healing response predominates, dense peritendinous adhesions form between the tendon, the fibroosseous sheath, and the surrounding periosteum. These adhesions restrict tendon excursion, leading to a profound discrepancy between passive and active range of motion (ROM).

The primary objective of flexor tenolysis is to meticulously liberate the adherent tendon from surrounding scar tissue, restoring its gliding mechanism without compromising its vascularity or structural integrity. This procedure is strictly indicated as a salvage operation when a patient has reached a definitive plateau in postoperative rehabilitation—typically no earlier than 3 to 6 months following the index surgery.

Clinical Pearl: Tenolysis should never be performed prophylactically or prematurely. The soft tissue envelope must be supple, the scars mature, and the joints mobilized to their maximum passive capacity before surgical intervention is considered. If passive motion is poor, tenolysis will fail; joint contractures must be addressed either prior to or concurrently with the tenolysis.

PREOPERATIVE EVALUATION AND BIOMECHANICS

Assessing Tendon Adherence

A thorough clinical examination is paramount to localize the exact site of adherence. The biomechanical presentation of tendon adhesions is highly predictable based on the anatomical zone of injury:
* Sublimis (Flexor Digitorum Superficialis - FDS) Adherence: The FDS tendon most commonly adheres to the proximal phalanx. This tethers the tendon and creates a persistent flexion contracture of the proximal interphalangeal (PIP) joint.
* Profundus (Flexor Digitorum Profundus - FDP) Adherence: The FDP tendon typically adheres to the middle phalanx, resulting in a flexion contracture of the distal interphalangeal (DIP) joint.
* Extensor Tendon Adherence: While primarily a flexor issue, concurrent extensor adhesions to the metacarpal shaft or proximal phalanx can exacerbate stiffness and must be evaluated.

Adherence to Fracture Sites

Tendon adherence is exponentially more severe when associated with phalangeal fractures. The adherence of a tendon to a fracture site is usually associated with one of four primary factors:
1. Volar Angulation: Poor reduction of a phalangeal fracture with volar apex angulation directly impinges on the flexor apparatus.
2. External Pressure: Improper splinting or external pressure forcing the tendon against the fracture callus during the healing phase.
3. Crush Injuries: Severe soft tissue trauma that obliterates the gliding planes and induces massive fibroblastic proliferation.
4. Laceration of the Tendon Sheath: Disruption of the synovial barrier allows osteoblasts and fibroblasts from the fracture site to directly invade the tendon.

ANESTHESIA AND POSITIONING

The advent of Wide-Awake Local Anesthesia No Tourniquet (WALANT) has revolutionized flexor tenolysis. Utilizing a mixture of lidocaine and epinephrine allows for profound local anesthesia and hemostasis without the need for a pneumatic tourniquet or general anesthesia.

Surgical Warning: If a regional or local block anesthetic is used for the tenolysis, the patient can voluntarily show the amount of motion in the finger intraoperatively. This active participation is invaluable; it provides immediate visual confirmation that the adhesions have been completely released and that the tendon is structurally intact enough to withstand active contraction.

If general anesthesia is utilized, the surgeon must rely on the traction effect by making a separate incision in the distal forearm to pull the proximal tendon, confirming that the finger can be moved through a nearly normal full range of motion.

SURGICAL TECHNIQUE: STEP-BY-STEP

1. Incision and Exposure

Make the incision through the existing skin scar to avoid creating new ischemic skin bridges. Bruner zigzag incisions or mid-lateral approaches are standard.
* When elevating the skin flaps, exercise extreme caution to avoid injury to the neurovascular bundles, which are often displaced or encased in scar tissue from the previous trauma.
* Preserve the annular portions of the fibroosseous sheath (specifically the A2 and A4 pulleys) at all costs.

2. Dissection and Tendon Release

Using great care, dissect the scar tissue from the tendon. In severe cases, the tendon and the fibroosseous sheath are visually indistinguishable.
* Begin the dissection in areas of normal anatomy, typically proximal and distal to the zone of maximal injury, and work toward the epicenter of the scar.
* Use sharp dissection (e.g., a #15 blade) and fine periosteal elevators to free the flexor tendon from the adherent periosteum and fibroosseous sheath.
* Similarly, the tendon sometimes adheres densely to the phalanx, particularly in areas of healed fracture callus. Elevate the tendon off the bone meticulously to avoid fraying the tendon fibers.

3. Management of Irregular Bony Surfaces

Sometimes, especially with comminuted fractures in which irregular bony surfaces are exposed after elevating the tendon, the risk of immediate readherence is exceptionally high. In these specific salvage scenarios, silicone sheeting has been interposed between the tendon and the bone to act as a physical barrier.

Adhesions Silastic sheet

This silicone sheeting prevents the raw tendon surface from adhering to the osteogenic fracture callus. It is left in place during the early rehabilitation phase and removed later after satisfactory active motion has been established.

Adhesions Silastic sheet

4. Intraoperative Assessment of Motion

Once the tendon appears visually free, its functional excursion must be tested.
* Under WALANT: Ask the patient to actively flex and extend the digit. Observe the tendon gliding beneath the preserved pulleys.
* Under General Anesthesia: After determining that the tendon has been completely released in the digit, make an incision in the distal forearm, identify the appropriate flexor tendon, and show with traction on the proximal tendon that the finger can be moved through a nearly normal full range of motion.

5. Addressing Joint Contractures

If flexion contractures are present at the proximal and distal interphalangeal joints that do not resolve with tenolysis alone, release these by capsulotomy. This is usually achieved by the release of the proximal extensions (checkrein ligaments) of the palmar plate.

6. Contingency Planning: Unsalvageable Tendons

During tenolysis, the surgeon may discover that the tendon is severely attenuated, partially ruptured, or structurally insufficient to withstand active motion.
* If the flexor tendon cannot be salvaged because of extensive injury, or if the flexor tendon graft has ruptured, the tenolysis must be converted to the first stage of a two-stage flexor tendon graft reconstruction.
* Insert a silicone rod (Hunter rod) beneath any remaining or reconstructed pulleys.
* If it can be shown that the annular pulleys are not present, or if the remaining pulleys are insufficient for proper finger function, perform pulley reconstruction over the silicone rod at the time of the index procedure.

7. Contingency Planning: Irreparable Profundus Damage

In cases where the FDS is intact and functioning well, but the FDP is irreparably damaged or ruptured in Zone I/II, restoring DIP joint stability becomes the priority. A tenodesis or arthrodesis of the DIP joint is indicated.

FLEXOR TENOLYSIS AFTER REPAIR AND GRAFTING Surgical Diagram

Before tenodesis, the distal interphalangeal joint is unstable and hyperextends during pinch, severely compromising grip strength and fine motor function.

FLEXOR TENOLYSIS AFTER REPAIR AND GRAFTING Surgical Diagram

After tenodesis, the joint is stable and remains partially flexed (typically positioned at 10 to 15 degrees of flexion) during pinch, providing a rigid post against which the thumb can oppose.

CONCURRENT EXTENSOR TENDON ADHESIONS

While addressing the flexor surface, the surgeon must remain cognizant of the extensor mechanism. An extensor tendon usually adheres to the metacarpal shaft or proximal phalanx following crush injuries or fractures. Surgery may be indicated when the tendon fails to loosen by active exercise, as determined by measurements of motion of adjacent joints. Techniques such as the Howard technique are employed to free the adherent extensor tendon, ensuring that reciprocal active extension is not blocking the newly restored flexor excursion.

PHARMACOLOGIC ADJUNCTS

The use of pharmacologic agents to prevent adhesion reformation remains controversial.
* Corticosteroids: Usually, corticosteroids are not instilled into the wound bed. While they decrease fibroblastic proliferation, they also severely inhibit intrinsic tendon healing and increase the risk of spontaneous postoperative tendon rupture.
* Pain Control: Indwelling catheters for pain control with local anesthetics rarely are used, although they can be highly helpful in controlling immediate postoperative pain, thereby facilitating early active motion.

POSTOPERATIVE CARE AND REHABILITATION

The success of a flexor tenolysis is entirely dependent on the postoperative rehabilitation protocol. The biological race between restoring tendon glide and the reformation of scar tissue begins immediately in the recovery room.

Immediate Postoperative Phase (Days 1-3)

A compression dressing is applied in the operating room, usually with the fingers in mild flexion, allowing the thumb metacarpophalangeal and interphalangeal joints to be in extension or only slight flexion.
Drains usually are unnecessary. Any drains that are placed are removed at approximately 24 hours or when drainage has ceased.
Postoperative rehabilitation is begun with active motion on the first day after surgery. The patient must be psychologically prepared to push through mild to moderate discomfort to maintain the glide achieved intraoperatively.

Early Mobilization Phase (Weeks 1-3)

Although an early postoperative mobilization program can be undertaken, it requires strict compliance.
The tenodesis effect is utilized heavily in therapy: active extension of the wrist can initiate passive flexion of the metacarpophalangeal joint through the adherent tendon. Similarly, active flexion of the DIP joint can be increased by passive flexion of the PIP joint.
The sutures are removed at 10 to 14 days.
The initial splint is left in place for approximately 3 weeks, and then gentle active motion is progressed.

Intermediate to Late Phase (Weeks 4-12)

The thumb (if involved) is protected with an additional removable dorsal splint for another 3 to 4 weeks, and motion exercises are increased.
Because the tendon has been surgically stripped of its vascular adhesions, it undergoes a period of transient avascularity and structural weakness. Therefore, forceful resistance activities are strictly prohibited and are not undertaken for 10 to 12 weeks postoperatively to prevent catastrophic rupture.

Clinical Pearl: The patient must understand that tenolysis is not a "quick fix." It is a reset of the rehabilitation clock. Failure to adhere to the strict active motion protocols, or conversely, applying excessive resistive force too early, will result in either recurrent stiffness or tendon rupture, both of which represent devastating complications.

Authoritative Medical Review

This academic synthesis is based on established protocols from Hutaifortho's Operative Orthopaedics and has been medically reviewed by Prof. Dr. Mohammed Hutaif, Consultant Orthopedic & Spine Surgeon. It is designed to assist orthopedic residents, fellows, and practicing surgeons in surgical preparation and board reviews (AAOS, FRCS, Arab Board).

Clinical Disclaimer: The surgical techniques, indications, and medical guidance detailed herein are for advanced educational purposes only. They do not supersede institutional guidelines or independent surgical judgment.

Flexor Tendon Repair: A Comprehensive Orthopedic Guide

Flexor Tenolysis After Repair and Grafting: Master Surgical Guide

Key Takeaway