What is the recommended evaluation and management for a patient with loss of flexion of the ring finger after it was caught in a shirt, suggesting possible flexor tendon injury?

Ring Finger Flexion Loss After Caught in Shirt

Start with a 3-view radiograph of the hand immediately to rule out avulsion fracture, then perform focused physical examination to isolate DIP joint flexion and determine if this is a flexor digitorum profundus (FDP) injury requiring urgent surgical referral within 7 days. 1

Initial Evaluation Algorithm

Immediate Imaging

• Obtain 3-view radiographs of the hand (PA, lateral, and oblique views) as the first step 1
• Look specifically for:
  • Avulsion fracture fragment at the distal phalanx base (indicates FDP avulsion with bone)
  • Any phalangeal fractures
  • Joint malalignment

Critical Physical Examination Findings

After imaging, perform these specific tests:

• Isolate DIP joint flexion: Have patient flex only the DIP joint while you stabilize the PIP joint

  • If unable to flex DIP → complete FDP rupture
  • Check the cascade of fingers at rest (disrupted cascade suggests tendon injury) 2

• Determine injury type (this dictates timing):

  • Type I (no bone fragment on X-ray, tendon retracts to palm): Most urgent - repair within 7 days 3
  • Type II (small bone fragment, tendon at PIP level): Can repair up to a few months later 3
  • Type III (large bone fragment, tendon stays at DIP): Less urgent but still needs fixation if fragment >1/3 articular surface 3

Management Based on Findings

If Radiographs Show Avulsion Fracture

• Refer to hand surgeon within 7 days for primary repair 3, 4
• Large fragments (>1/3 articular surface) require open reduction and internal fixation 1

If Radiographs Negative but Cannot Flex DIP

This is a closed FDP rupture - the ring finger is the most commonly affected digit 5, 3

Critical timing consideration: If the tendon has retracted into the palm (you'll feel an empty sheath and possibly a lump in the palm), blood supply is compromised and repair must occur within 7 days for optimal outcome 3

• Urgent hand surgery referral (within 3-5 days ideally) 4
• Do NOT delay with "wait and see" approach - delayed diagnosis leads to functional impairment 1

Advanced Imaging if Diagnosis Unclear

If physical exam is equivocal or you need to localize the rupture level for surgical planning:

• MRI without contrast or ultrasound are equivalent options 1
• MRI shows:
  • Level of tendon retraction (critical for surgical planning) 1
  • Quality of tendon stump 1
  • Associated pulley injuries 1
  • Sensitivity 92-100% for flexor tendon injuries 1

Key Pitfalls to Avoid

1. Don't miss the 7-day window: Type I injuries (tendon retracted to palm) have compromised blood supply and must be repaired within one week 3

2. Don't rely on 2-view X-rays alone: Standard 3-view examination is essential - 2 views miss fractures 1

3. Don't assume partial function means no surgery needed: Even if patient has some flexion from intact FDS, the FDP may still be ruptured and require repair 2

4. Don't delay imaging for "conservative management": The traditional approach of casting and repeating X-rays in 10-14 days causes functional impairment in tendon injuries 1

Surgical Principles (For Referral Context)

Modern repair requires 4, 6:

• Minimum 4-strand core suture technique
• Early active motion within 3-5 days post-op
• Strong repair to allow early mobilization and prevent adhesions

Bottom line: This mechanism (finger caught in clothing) is classic for FDP avulsion ("jersey finger"). Get X-rays immediately, test isolated DIP flexion, and if positive, refer to hand surgery within 7 days - earlier is better. 3, 4