Flexor Tendon Injuries – Treatment & Rehabilitation

Overview

• Flexor tendon injuries require:
  • Early diagnosis
  • Timely repair
  • Structured rehabilitation

Goals of treatment:

• Restore tendon gliding
• Preserve finger motion
• Recover hand function

Successful outcomes depend on:

• Strong repair technique
• Protection of repair
• Supervised hand therapy

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Timing of Repair

• Repair should be performed as early as possible
• Ideally within 2 weeks of injury

Delayed repair increases risk of:

• Adhesions
• Tendon retraction
• Poor tendon gliding

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Zone 2 Flexor Tendon Injuries

Importance

• Zone 2 is the “no man’s land” of flexor tendon surgery
• Tendon gliding is easily compromised

Important principle:

• Repairing only one slip of FDS may improve tendon gliding in selected cases

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Partial Tendon Lacerations

>60% Tendon Width

• Usually requires repair

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<60% Tendon Width

• Often managed conservatively

If triggering occurs:

• Trim frayed tendon edges

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Wide-Awake Tendon Repair

Advantages

Performed under local anesthesia.

Benefits:

• Allows active finger movement during surgery
• Assesses:
  • Tendon gliding
  • Repair tension
  • Gapping

Increasingly popular technique.

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Principles of Flexor Tendon Repair

1. Strong Repair

Repair must allow:

• Early controlled motion

Most important factor:

• Number of core suture strands crossing repair

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2. Epitendinous Suture

Benefits:

• Adds repair strength
• Improves tendon handling
• Enhances gliding

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3. Avoid Gap Formation

Important point:

• Gap >3 mm increases risk of repair failure

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4. Preserve Pulleys

Important pulleys:

• A2 pulley
• A4 pulley

In thumb:

• Preserve pulley system whenever possible

Loss of pulleys causes bowstringing and poor flexion mechanics.

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Postoperative Rehabilitation

Importance of Early Therapy

Early controlled motion:

• Reduces adhesions
• Improves tendon excursion
• Improves function

Requires strong repair.

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Splint Protection

Dorsal Blocking Splint

Commonly used after repair.

Position:

• Wrist flexion
• MCP flexion

Purpose:

• Reduce tension on repair
• Permit safe controlled motion

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Rehabilitation Progression

Early Phase

• Protected passive flexion

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Intermediate Phase

• Active ROM gradually introduced

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Late Phase

• Resistance exercises after adequate healing

Progression depends on:

• Repair strength
• Rehabilitation protocol

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Flexor Tendon Repair in Children

• Young children often treated with cast immobilization for ~4 weeks
• Compliance with therapy may be difficult

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Reconstruction of Flexor Tendon Injuries

Indications

• Failed primary repair
• Chronic loss of active flexion
• Preserved passive motion

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Single-Stage Reconstruction

Indications:

• Intact tendon sheath
• Good gliding environment

Technique:

• Tendon grafting performed in one stage

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Two-Stage Reconstruction

Indications:

• Collapsed tendon sheath
• Poor tendon bed

Procedure:

Stage 1

• Silicone rod placement

Stage 2

• Tendon grafting after pseudosheath formation

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Thumb Flexor Tendon Injuries

Flexor Pollicis Longus (FPL) Rupture

May occur after:

• Volar plating of distal radius fracture

Cause:

• Prominent volar plate irritating tendon

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Chronic Thumb Flexor Loss

If passive motion preserved:

• Tendon transfer may restore function

Common transfer:

• Flexor digitorum superficialis (FDS) transfer

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Important Complications

1. Adhesions

Most common complication.

Especially common in:

• Zone 2 injuries

Features:

• Poor active motion
• Passive motion preserved

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2. Tendon Rupture

Highest risk:

• Early postoperative period

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3. Quadriga

Occurs after excessive advancement of FDP tendon.

Leads to:

• Flexion imbalance
• Reduced flexion in adjacent fingers

Important in:

• Jersey finger repair

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Tenolysis

Indications

• Passive motion preserved
• Active flexion limited due to adhesions

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Initial Management

• Aggressive hand therapy first

Usually wait:

• At least 3 months before considering tenolysis

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High-Yield Exam Pearls

• Zone 2 injuries have highest adhesion risk

• 60% partial laceration usually repaired

• Strong repair allows early mobilization
• Gap >3 mm increases rupture risk
• Preserve A2 and A4 pulleys
• Dorsal blocking splint protects repair
• FPL rupture may occur after volar distal radius plating
• Passive ROM preserved + poor active motion = adhesions
• Tenolysis indicated after failed therapy with preserved passive motion