Wrist Ligament Instability

Non-operative management is appropriate only when the wrist is stable or when the patient's symptoms, demand, comorbidity or preference do not justify surgery.

Do not call non-operative care complete unless follow-up is planned. Dynamic instability can declare itself later.

Indications

• Acute complete scapholunate injury.
• Reducible SL interval.
• Repairable dorsal SL ligament or avulsion.
• No established arthritis.
• Patient has functional demand that justifies operative stabilisation.

Technique principles

1. Supine position, hand table, tourniquet and image intensifier.
2. Confirm stress instability and reducibility under fluoroscopy.
3. Use a dorsal longitudinal or transverse wrist approach centred over the third/fourth compartments.
4. Protect superficial radial sensory branches and dorsal veins.
5. Open the extensor retinaculum as needed and protect extensor tendons.
6. Perform dorsal capsulotomy, often ligament-sparing or Berger-type according to surgeon preference.
7. Inspect the SL interval, cartilage and reducibility.
8. Reduce scaphoid extension/flexion malalignment and lunate extension with joysticks or pointed reduction clamps.
9. Temporarily fix with K-wires across scapholunate and often scaphocapitate intervals.
10. Repair dorsal SL ligament using transosseous sutures or suture anchors when tissue allows.
11. Add dorsal capsulodesis if needed to reinforce scaphoid control.
12. Confirm SL gap, SL angle and carpal alignment on PA and lateral fluoroscopy.
13. Immobilise in a cast or splint; remove K-wires commonly around 8 to 12 weeks according to construct and local protocol.
14. Start supervised hand therapy after stability and healing permit.

Pitfalls

• Repairing an unreduced carpus.
• Missing cartilage damage.
• Ignoring associated distal radius, scaphoid, LT or TFCC injury.
• Removing wires too early or failing to protect the repair.

Chronic reducible scapholunate instability is not a simple repair problem. The ligament is attenuated and the secondary stabilisers may have stretched. The aim is a stable, useful wrist with pain reduction and delayed collapse, not restoration of perfectly normal carpal kinematics.

Reconstruction checklist

1. Confirm no radioscaphoid or capitolunate arthritis.
2. Confirm the carpus is reducible under fluoroscopy.
3. Correct scaphoid flexion and lunate extension before fixation.
4. Use K-wire protection or internal fixation according to technique.
5. Counsel that recurrence of radiographic gap does not always equal clinical failure, but pain and collapse progression matter.

Acute or dynamic LT injury

1. Confirm ulnar-sided symptoms, compare to the other wrist and exclude TFCC, ECU and ulnar impaction.
2. Use radiographs, MRI/MRA and arthroscopy when symptoms persist.
3. Partial stable tears may be treated with immobilisation or arthroscopic debridement.
4. Complete unstable tears can be repaired and pinned if acute and reducible.
5. Temporary LT or triquetrohamate pinning may protect the repair.

Chronic LT instability

Chronic LT instability is difficult. Options include reconstruction, capsulodesis, LT arthrodesis or other salvage, but the decision must be cautious because stiffness, nonunion and persistent pain can occur.

Key decision points

• Is the VISI reducible?
• Is there midcarpal instability?
• Is TFCC pathology the main pain generator?
• Is there ulnar-positive variance or ulnocarpal impaction?
• Is there degenerative change?

Salvage is appropriate when deformity is fixed, reconstruction is unlikely to hold, or cartilage is already damaged.

Purpose: confirm ligament grade, dynamic instability, cartilage condition and associated TFCC or chondral injury.

Steps

1. Supine position, arm table, traction tower or wrist traction setup.
2. Mark Lister's tubercle, EPL, 3-4 portal, 4-5 portal, 6R/6U portals and midcarpal portals.
3. Establish 3-4 portal for radiocarpal viewing.
4. Inspect radius, scaphoid fossa, lunate fossa, proximal scaphoid, lunate, TFCC and SL interval.
5. Probe SL and LT ligaments; assess step-off and whether a probe or scope passes through the interval.
6. Use midcarpal portals to assess SL/LT interval from the opposite side, capitolunate joint and cartilage.
7. Treat according to grade: debridement for stable partial tears, pinning/repair for unstable acute tears, reconstruction or salvage if chronic.

Hazards: superficial radial nerve, dorsal sensory branches, ECU subsheath, extensor tendons and iatrogenic chondral injury.

Indication: acute complete SL injury, reducible interval, repairable dorsal ligament tissue and no arthritis.

Postoperative care: immobilise and protect the pin construct. K-wires are commonly removed after a protected healing period, often around 8 to 12 weeks depending construct and local protocol. Rehabilitation starts with protected motion, then grip strengthening and load progression only after stability and healing are satisfactory.

Indication: chronic reducible scapholunate instability with preserved cartilage and high functional demand.

Concept: reconstruct secondary restraints that resist scaphoid flexion and SL diastasis.

Contraindications: fixed irreducible DISI, radioscaphoid or midcarpal arthritis, poor patient tolerance for stiffness, severe low-demand arthritic pain pattern, infection or inability to comply with prolonged protection.

Technique principles

1. Confirm reducibility and no arthritis before committing.
2. Harvest a strip of flexor carpi radialis while maintaining distal attachment in many techniques.
3. Pass the graft through a scaphoid tunnel or around the scaphoid according to technique.
4. Reduce the scaphoid and lunate anatomically.
5. Secure graft dorsally to lunate/triquetrum or dorsal radiocarpal/dorsal intercarpal structures depending method.
6. Protect the reconstruction with K-wires or internal fixation.
7. Confirm SL gap, SL angle and capitolunate alignment.

Trade-offs: stiffness, loss of flexion, recurrent widening, hardware irritation and incomplete restoration of normal mechanics.

Indication: painful SLAC/SNAC-type collapse with preserved radiolunate cartilage where motion preservation is desired.

Technique principles

1. Dorsal approach to the wrist.
2. Confirm cartilage pattern; radiolunate cartilage must be preserved.
3. Excise scaphoid.
4. Prepare lunate, triquetrum, capitate and hamate fusion surfaces.
5. Correct DISI and align the lunate.
6. Add cancellous bone graft.
7. Fix with headless screws, staples, plate or other construct according to surgeon preference.
8. Immobilise until union; monitor nonunion and hardware irritation.

Failure modes: nonunion, dorsal impingement, hardware irritation, persistent pain, loss of motion and progression of arthritis.

Indication: painful collapse wrist with preserved capitate head and lunate fossa cartilage.

Technique principles

1. Dorsal wrist approach.
2. Inspect capitate head and lunate fossa cartilage before committing.
3. Excise scaphoid, lunate and triquetrum.
4. Preserve volar radiocarpal ligaments.
5. Ensure capitate sits concentrically in the lunate fossa.
6. Close capsule and begin protected rehabilitation according to stability and pain.

Avoid PRC when: capitate head cartilage is severely damaged, lunate fossa cartilage is poor, or demand makes loss of strength unacceptable.