What is a concise overview of the evaluation and management of scapholunate injuries in a patient presenting with wrist pain after a fall on an outstretched hand?

Scapholunate Ligament Injuries: Clinical Overview

Initial Evaluation and Diagnosis

Begin with conventional radiographs with careful attention to positioning to assess for carpal malalignment, looking specifically for scapholunate diastasis >4 mm and dorsal lunate tilt >10°, which indicates dorsal intercalated segmental instability (DISI). 1, 2

Clinical Presentation

• Typically results from a fall on an outstretched hand (FOOSH) with the wrist extended and supinated 3, 4
• Presents with radial-sided wrist pain, weakness, and clicking 3
• May occur in conjunction with distal radius fractures 5
• Natural history is poorly understood—not all injuries progress to scapholunate advanced collapse (SLAC) wrist arthritis 3

Physical Examination Findings

• Tenderness over the scapholunate interval dorsally 3
• Positive Watson scaphoid shift test 3
• Reduced grip strength compared to contralateral side 4
• Pain with loading maneuvers 4

Imaging Algorithm

First-Line: Conventional Radiographs

• Start with standard PA, lateral, and clenched fist views 1, 2
• In low-grade injuries, radiographs are usually normal 1
• Look for scapholunate gap >4 mm (Terry Thomas sign) and scapholunate angle >60° 1, 2

Advanced Imaging When Radiographs Are Normal or Equivocal

CT arthrography has the highest sensitivity (nearly 100%), specificity, and accuracy for detecting scapholunate ligament tears and should be the preferred advanced imaging modality. 1, 2

• CT arthrography detects partial ligament tears more accurately than MR arthrography with greater interobserver agreement 2
• CT arthrography is more sensitive for tears of the biomechanically important dorsal ligament fibers compared to conventional MRI 1

Alternative Advanced Imaging Options:

• 3T MRI: Sensitivity 65-89% for scapholunate tears, specificity 90-97% 6, 1
• MR arthrography: Superior to non-contrast MRI and identifies which specific ligament segments are torn—critical for surgical planning 6, 1, 2
• High-frequency ultrasound with dynamic "clenched fist" maneuvers: Sensitivity 46-100%, specificity 92-100% for dorsal band tears 6, 1

Important caveat: Both MRI and MR arthrography have poor to moderate sensitivity for partial ligament tears 6

Classification and Treatment Strategy

Acute Complete Tears (Within 3-6 Weeks)

Anatomic repair of the scapholunate ligament usually leads to satisfactory results, and many surgeons augment the repair with capsulodesis techniques. 3

• Direct ligament repair should be performed when tissue quality permits 3
• Augmentation with dorsal capsulodesis improves stability 3
• Early rehabilitation protocols can be initiated with stable fixation 7

Chronic Injuries with Reducible Malalignment (Garcia-Elias Stages 2-4)

All-arthroscopic dorsal capsulo-ligamentous repair provides reliable results with the advantage of early rehabilitation and prevention of postoperative stiffness. 4

• The dorsal scapholunate complex (ligament plus dorsal capsule) is critical for stability, not just the ligament itself 4, 8
• Arthroscopic repair at mean follow-up >2 years shows: 4
  • Mean grip strength 93.4% of unaffected side
  • Flexion reaching 84.3% of unaffected wrist
  • Mean DASH score improvement from 46.04 to 8.3
  • Correction of DISI deformity in all cases
• Motion averages 60-80% of contralateral side with various reconstruction techniques 3

Chronic Injuries with Static Irreducible Malalignment

• Presence of static malalignment usually leads to inferior outcomes 3
• Various reconstruction techniques (tendon grafts, capsulodesis, 360-degree tenodesis with internal bracing) have been developed 3, 7
• Grip strength averages 65-90% with reconstructive procedures 3

Injuries with Cartilage Loss (SLAC Wrist)

Once cartilage loss is present, only salvage procedures are available, tailored to the degree of arthritis. 3

• Options include proximal row carpectomy, four-corner fusion, or total wrist arthrodesis 3
• Choice depends on extent and location of arthritic changes 3

Conservative Management for Partial Tears

Gradual rehabilitation and physical therapy focusing on progressive strengthening is recommended for partial tears. 2, 9

Acute Phase Protocol:

• Apply cryotherapy through wet towel for 10-minute periods for short-term pain relief 9
• Activity modification to reduce provocative movements while maintaining some wrist motion 9
• Avoid complete immobilization beyond 6 weeks to prevent muscular atrophy and joint stiffness 9

Rehabilitation Progression:

• Begin gentle range of motion exercises once acute pain subsides (typically after 3-6 weeks) 9
• Progress to isometric exercises before advancing to eccentric strengthening 9
• Incorporate tensile loading exercises to stimulate collagen production and guide normal collagen fiber alignment 9

When Conservative Management Fails:

Surgical treatment should be considered when conservative management fails after 3-6 months of appropriate treatment. 9

Critical Pitfalls to Avoid

• Never inject corticosteroids directly into the ligament substance—this may inhibit healing, reduce tensile strength, and predispose to spontaneous rupture 9
• Avoid prolonged complete immobilization beyond 6 weeks 9
• Do not rely solely on conventional radiographs in acute injuries—they are often normal in low-grade injuries 1
• Dynamic instability may be missed on MRI unless sequences are performed in pronation and supination 6
• MRI and MR arthrography have limited accuracy for extrinsic ligament assessment 6

Key Anatomical Concept

Recent arthroscopic findings demonstrate that scapholunate stability is maintained by an entire anatomic complex consisting of well-defined capsuloligamentous structures and extrinsic ligaments, not just the scapholunate ligament itself. 8

• The dorsal scapholunate ligament's attachment to the dorsal capsule is critical for stability 4
• This understanding has shifted surgical approaches toward reconstructing the entire dorsal scapholunate complex rather than the ligament alone 8, 5