What is the treatment for a scapholunate (wrist ligament) membranous portion partial tear?

Treatment for Scapholunate Membranous Portion Partial Tear

Conservative treatment is the first-line approach for partial scapholunate ligament tears, especially when secondary stabilizers are intact, as it can achieve significant pain reduction and functional recovery. 1

Diagnosis and Characterization

Scapholunate ligament tears occur most commonly from a fall on an outstretched hand and can range from partial to complete tears. The scapholunate interosseous ligament (SLIOL) has three portions:

• Dorsal portion (strongest and most critical for stability)
• Volar portion
• Membranous (proximal) portion

When evaluating these injuries, it's important to understand:

• Partial tears of the membranous portion are less likely to cause instability compared to complete tears or tears involving the dorsal portion
• Radiographs may appear normal in partial tears, as scapholunate dissociation (gap ≥4 mm) typically only occurs with more severe injuries 2, 3
• Advanced imaging is needed for accurate diagnosis

Imaging Recommendations

1. Initial radiographs: Look for widened scapholunate gap (≥4 mm) and abnormal scapholunate angle (>70°) 3

2. Advanced imaging options (in order of diagnostic accuracy for partial tears):

   • CT arthrography: Highest sensitivity (nearly 100%), specificity, and accuracy for detecting scapholunate ligament tears 2
   • MR arthrography: Good accuracy but less sensitive than CT arthrography for partial tears 2
   • 3T MRI: Better than 1.5T MRI, with sensitivities of 65-89% for scapholunate tears 2
   • Ultrasound: Variable sensitivity (46-100%) for dorsal band tears, can be enhanced with dynamic "clenched fist" maneuvers 2

Treatment Algorithm

1. Conservative Management (First-Line for Partial Tears)

For partial tears without instability or when secondary stabilizers are intact:

• Immobilization with wrist splint or cast for 4-6 weeks
• Followed by progressive rehabilitation
• Anti-inflammatory medications for pain control

Conservative treatment is particularly effective for:

• Acute injuries
• Partial tears without extrinsic ligament involvement
• Cases without static instability 1

2. Arthroscopic Intervention (For Persistent Symptoms)

If conservative treatment fails after 3-6 months:

• Arthroscopic debridement and thermal shrinkage:

  • Effective for pain relief in partial tears (Geissler grades I and II)
  • Studies show 14/16 patients experienced substantial pain relief
  • Maintains stability with no progression to static instability 4

• Arthroscopic dorsal capsulo-ligamentous repair:

  • For reducible scapholunate instability (Garcia-Elias stages 2-4)
  • Provides reliable results with early rehabilitation
  • Prevents post-operative stiffness 5

3. Open Surgical Procedures (For Progressive Instability)

For cases with developing instability despite conservative or arthroscopic treatment:

• Direct repair with capsulodesis: For acute injuries with repairable tissue
• Ligament reconstruction: For chronic injuries with irreparable tissue

Monitoring and Outcomes

• Regular follow-up to assess:

  • Pain reduction (using VAS score)
  • Functional recovery (using DASH and PRWE scores)
  • Grip strength
  • Range of motion
  • Radiographic stability

• Watch for signs of progression to scapholunate advanced collapse (SLAC) wrist, which may eventually require salvage procedures 6

Important Considerations

• The natural history of untreated partial scapholunate tears is not well understood - not all progress to instability or arthritis 6
• Partial tears of the membranous portion alone are less likely to cause instability than those involving the dorsal portion, which is critical for stability 5
• Early diagnosis and appropriate treatment are essential to prevent progressive carpal malalignment and eventual arthritis 3
• The presence of intact secondary stabilizers (extrinsic ligaments) is associated with better outcomes with conservative treatment 1

Conservative management should be tried first for partial scapholunate ligament tears, with surgical intervention reserved for cases that fail to respond to non-operative measures or show signs of progressive instability.