What is the recommended management for an acute rupture of the little finger tendon (flexor digitorum profundus or extensor digitorum minimi) in an otherwise healthy adult?

Management of Pinky Finger Tendon Rupture

Acute ruptures of the little finger flexor or extensor tendons require immediate primary surgical repair followed by early protected mobilization, as primary repair consistently produces superior functional outcomes compared to delayed reconstruction or conservative management.

Initial Assessment and Diagnosis

Clinical Examination Findings

• Flexor digitorum profundus (FDP) rupture: Loss of isolated distal interphalangeal (DIP) joint flexion when the proximal interphalangeal (PIP) joint is held in extension 1
• Extensor digiti minimi rupture: Loss of metacarpophalangeal (MCP) joint extension, though intrinsic muscles may partially compensate for proximal interphalangeal extension 2
• Palpable gap in the tendon substance or at the insertion site 1
• Imaging is not routinely necessary when clinical diagnosis is clear 3

Surgical Management Algorithm

Timing of Intervention

Immediate primary repair is strongly preferred as it produces 70-90% successful outcomes compared to significantly worse results with secondary reconstruction or tendon grafting 1. Delay beyond 2-3 weeks makes primary repair technically difficult and compromises outcomes 1.

Surgical Technique Selection

For Flexor Tendon Injuries (FDP)

• Primary repair using strong core sutures (minimum 4-strand technique) with epitendinous sutures to create smooth tendon junction 1
• Repair must achieve minimal gapping at the repair site while preserving tendon vascularity 1
• Secure suture knots with sufficient strength to withstand early mobilization forces 1
• Zone-specific considerations: Little finger FDP injuries in zone II (between A1 pulley and superficialis insertion) are most challenging due to confined space within the flexor sheath 1

For Extensor Tendon Injuries

• Zone-specific repair approach is critical 4:
  • Zone I (mallet finger): Conservative splinting in extension for 6 weeks unless there is displaced avulsion fracture requiring surgical fixation 4
  • Zone II-III: Primary repair with figure-of-eight sutures followed by extension splinting 4
  • Zone IV-VII: Primary repair with strong core sutures and 6 weeks extension splinting 4

Intraoperative Priorities

• Preserve as many pulley sections as possible, particularly A2 and A4 pulleys for flexor tendons 5
• Achieve smooth tendon junction to minimize adhesion formation 1
• Ensure adequate soft tissue coverage 5

Postoperative Rehabilitation Protocol

Early Protected Mobilization (Critical for Success)

Begin early active flexion with controlled passive extension within 2-4 weeks using a protective orthosis that limits terminal extension to prevent repair compromise 3, 6. This approach produces faster functional recovery without increasing rupture risk compared to immobilization 3, 6.

Specific Mobilization Guidelines

• Weeks 0-2: Protective orthosis limiting dorsiflexion/extension, early protected weight bearing of the hand 3, 6
• Weeks 2-4: Begin controlled active mobilization within protective device with free flexion but limited extension 3, 6
• Weeks 4-6: Progressive active range of motion exercises 7
• Weeks 6-12: Gradual strengthening and functional activities 7
• 3-6 months: Return to unrestricted activities and sports 3

Critical Rehabilitation Principles

• Patient compliance is absolutely essential to prevent complications 8, 6
• Non-compliance with protective devices significantly increases rerupture risk 8
• Hand therapy for minimum 3-6 months is mandatory to maintain gains 5

Complications and Management

Primary Complications to Monitor

• Tendon rupture: Occurs in 0-8% of cases, requires immediate surgical revision 5
• Adhesion formation: Most common complication limiting gliding function 1, 5
• Joint stiffness: Prevented by early mobilization protocols 7
• Deep vein thrombosis: Requires monitoring regardless of treatment approach 8, 6

Salvage Procedures for Failed Primary Repair

If primary repair fails or severe adhesions develop despite appropriate therapy, consider the reconstructive ladder 5:

1. Tenolysis at 3-6 months if passive range exceeds active range and soft tissues are mature 5
2. Staged flexor tendon reconstruction with tendon grafting for irreparable tendons 5
3. Arthrodesis, amputation, or ray resection for salvage in severe cases 5

Key Clinical Pitfalls to Avoid

• Delaying surgical repair beyond 2-3 weeks significantly compromises outcomes and may necessitate tendon grafting rather than primary repair 1
• Immobilization beyond 2-4 weeks increases adhesion formation and joint stiffness without reducing rupture risk 3, 7
• Inadequate patient education about compliance leads to preventable ruptures 8, 6
• Premature return to unrestricted activities before 3 months increases rupture risk 3
• Failure to preserve critical pulleys during repair compromises long-term function 5