The wound is explored and extended with Bruner (zig-zag) incisions to expose the tendon sheath. The cut tendon ends are retrieved and sutured together using a core suture technique (typically four-strand or six-strand) with an epitendinous (running peripheral) suture. Both FDP and FDS tendons are repaired if both are cut. The tendon sheath is repaired when possible. Neurovascular structures are repaired at the same time. The operation takes one to two hours per tendon.
All complete flexor tendon lacerations require surgical repair. Without repair, the ability to bend the finger is permanently lost. Primary repair within days of injury gives the best results. Late presentation (beyond three to four weeks) is much harder to treat.
Not appropriate for complete lacerations. Partial lacerations involving less than 50–60% of the tendon width may be managed with splinting and hand therapy.
Urgent assessment of tendon, nerve, and vascular function. X-ray to exclude fracture or foreign body. Surgery within 24 hours is ideal, though delayed primary repair up to two to three weeks is possible.
Restoration of finger flexion. Results depend on the zone of injury, the number of tendons divided, patient compliance with rehabilitation, and the hand therapy protocol. Zone II (within the flexor sheath) is the most challenging — good to excellent results in approximately 70–80%.
AdhesionsCommon
The most common problem. Scar tissue tethers the tendon, limiting glide. Risk is highest in Zone II.
StiffnessCommon
Loss of full extension (flexion contracture) or full flexion.
RuptureUncommon
The repair may fail, particularly with premature loading. Risk approximately 3–5% with modern techniques.
Tenolysis requirementCommon
Approximately 10–20% of Zone II repairs need a second operation to release adhesions.
BowstringingUncommon
If the pulleys are not reconstructed, the tendon may pull away from the bone during flexion.
TriggeringUncommon
Thickening at the repair site may catch on the pulleys.
InfectionUncommon
Wound or sheath infection.
Joint contractureUncommon
Prolonged immobilisation can cause permanent joint stiffness.
General, regional, or wide-awake local anaesthesia with no tourniquet (WALANT). WALANT allows active testing of the repair during surgery.
A dorsal blocking splint is applied with the wrist and fingers in a protected position. Early active motion protocols (Belfast, Manchester, or equivalent) begin within the first few days under hand therapist supervision — controlled flexion with the splint preventing full extension. Splint for four to six weeks. Progressive active extension from four weeks. Strengthening from eight weeks. Full recovery three to six months.
Hand therapy appointments twice weekly for six weeks, then weekly. Surgeon review at two weeks and six weeks.
Why is Zone II so difficult?
Zone II is within the flexor sheath — a tight fibrous tunnel. Both FDP and FDS tendons must glide freely within this confined space. Scar tissue formation (adhesions) is common and restricts the tendon gliding that is essential for finger movement.
Why is early movement so important?
Early controlled active motion stimulates tendon healing and prevents adhesions. Modern protocols have dramatically improved outcomes compared to older techniques that immobilised the hand for weeks.
What if adhesions limit my movement?
Tenolysis (a second operation to release adhesions) may be needed at three to six months if intensive hand therapy does not restore adequate movement.