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SCAPHOLUNATE LIGAMENT INJURY, WRIST

Introduction

The scapholunate interosseous ligament (SLIL) is the most commonly injured intercarpal ligament, which results in the most frequent pattern of carpal instability. Injuries to the scapholunate interosseous ligament typically occur after a fall on an outstretched hand (FOOSH) and affect a wide range of patients. These injuries are often not diagnosed or treated during the acute phase when direct repair of the ligament is possible. Undiagnosed scapholunate interosseous ligament injury or delayed scapholunate interosseous ligament injury treatment can result in a predictable pattern of radiocarpal arthritis. Managing scapholunate interosseous ligament injuries is also a significant clinical challenge for hand surgeons, as there is no gold standard for optimal treatment. Surgical intervention—including ligament reconstruction and repair—is usually necessary, and surgeons must determine which technique is most appropriate based on the stage and severity of the injury.1,2

Pathophysiology

  • The theorized mechanism of injury is high-energy trauma, usually from a FOOSH with extension, intercarpal supination and ulnar deviation, causing failure of the scapholunate interosseous ligament and scapholunate dissociation.1 Often this manifests as impact to the hypothenar eminence. Scapholunate interosseous ligament injuries are often associated with simulataneous radioscapholunate and radioscaphocapitate ligament injuries.
  • If scapholunate interosseous ligament instability develops, the wrist exhibits abnormal kinematics and is symptomatic during weight-bearing activities and normal arc of motion.
  • A scapholunate tear is the first stage of Mayfield’s four stage perilunate classification.  Mayfield’s four stages are: Stage I - tear of the scapholunate ligament; Stage II – disruption of the lunocapitate joint through the Space of Poirier; Stage III - lunotriquetral joint dissociation; and  Stage IV - lunate dislocation.12
  • Four types of instability have been defined: pre-dynamic instability, dynamic instability, reducible static instability and non-reducible static instability.4
  • Left untreated, this instability will lead to a predictable pattern of radiocarpal arthritis, referred to as scapholunate ligament advanced collapse (SLAC) arthritis of the wrist.1
  • The least severe presentation of instability is called “occult instability,” in which there is either a tear or attenuation of the scapholunate interosseous ligament but generally no radiographic findings; the only hint is pain with mechanical loading or painful clunks.1
  • In cases of severe hyperextension, the injury continues causing successive tears of the radioscapholunate, radioscaphocapitate, radiotriquetral and dorsal radiocarpal ligaments.1 This can lead to different types of carpal dislocations and subsequent carpal instability.
  • Degenerative ligament tears also occur in the elderly population, often with no history of wrist injury.1

Related Anatomy

  • The scapholunate interosseous ligament is a C-shaped structure. The scapholunate interosseous ligament is a true intra-articular ligament that is important for maintaining normal carpal alignment and kinematics.1 This ligament is bathed in synovial fluid, which contributes to its poor healing potential.5
  • The scapholunate interosseous ligament is divided anatomically and histologically into three parts: dorsal, intermediate, and volar
    • The intermediate is the weakest segment.
    • The dorsal is the most robust and strongest portion, as it is comprised mainly of collagen; it controls flexion and extension and is the primary restraint to distraction, torsion, and translationof the scaphoid.1,5
  • The volar contributes to rotational stability.
  • The SL ligament is an intrinsic ligament.
  • Extrinsic ligaments also confer stability to the SL articulation.  These include the dorsal intercarpal ligaments, the dorsal radiotriquetral, the radioscapholunate ligament and the radioscaphocapitate ligament.

Treatment Classification13

  • Stage 1: Partial scapholunate ligament injury
    • Partial tears typically only involve the volar and interosseous components.  The dorsal ligament is typically intact and therefore, a Watson shift test would be negative
  • Stage 2: Complete tear with a repairable ligament
    • Osseous avulsions have a better healing potential than intrasubstance tears
  • Stage 3: Complete tear with an irrepairable ligament and normal alignment
    • In this variant, the secondary stabilizers of the scaphoid are intact, resisting rotatory subluxation of the scaphoid
  • Stage 4: Complete tear with an irrepairable ligament and reducible rotatory subluxation of the scaphoid\
    • The scaphoid is reducible with manipulation, indicating that a soft tissue procedure may suffice, as opposed to arthrodesis
  • Stage 5: Complete tear with irreducible malalignment but no signs of significant arthritis
  • Stage 6: Chronic SL tear with arthritic change (SLAC wrist)

Incidence and Related Conditions

  • The prevalence of scapholunate interosseous ligament injuries, as well as the rate of symptomatic instability and/or arthritis after injury, has not been clearly elucidated and likely underestimated because it is often missed on initial presentation.1,5
  • The natural history of these injuries is also essentially unknown.5
  • Frequently scapholunate interosseous ligament injuries are associated with distal radius fractures – 10-30% of intra-articular distal radius fractures have some injury to the SL ligament
  • High energy injuries can lead to sequential tearing of other intercarpal ligaments including the capitolunate, lunotriquetral, and dorsal radiocarpal ligaments.  This can lead to lunate dislocations, perilunate dislocations and various forms of carpal instability.  Therefore, these injuries should be thought of as a continuum
  • Dorsal intercalated segment instability (DISI) deformity – instability of the proximal carpal row, also knowns as the “intercalated segment” because no tendons insert upon them.  In DISI, the scaphoid flexes, while the lunotriquetral complex extends.  This is in contrast to VISI, seen with LT tears, where the scapholunate complex flexes and the triquetrum extends.
  • SLAC wrist – progressive arthritic degeneration of the wrist secondary to altered biomechanics seen in DISI due to an untreated SL tear

Differential Diagnosis

  • Sprained wrist
  • Scaphoid impaction syndrome (SIS)
  • Occult ganglion cyst
  • Posterior interosseous nerve neuroma
  • Ulnar translocation
  • Lunotriquetral coalition
  • Perilunate dislocation
  • Dorsal Wrist Capsular Impingement9

Special Work up

  • Radiographs
    • Clenched fist view – accentuates SL gapping
      • Gap > 3 mm – positive Terry Thomas sign indicating an SL ligament injury10
    • SL angle > 70 degrees on a lateral radiograph indicates DISI
    • Flouroscopy and mini-flouroscopy can be very herlpful when attempting to diagnose scapholunate interosseous ligament tears10
  • Arthroscopy
    • Gold standard for diagnosis
    • Drive through sign – Ability to enter the midcarpus from the radiocarpal joint through the torn scapholunate interosseous ligament.
 
ICD-10 Codes

  • SCAPHOLUNATE LIGAMENT INJURY, WRIST

    Diagnostic Guide Name

    SCAPHOLUNATE LIGAMENT INJURY, WRIST

    ICD 10 Diagnosis, Single Code, Left Code, Right Code and Bilateral Code

    DIAGNOSISSINGLE CODE ONLYLEFTRIGHTBILATERAL (If Available)
    SCAPHOLUNATE LIGAMENT INJURY, WRIST S63.512_S63.511_ 

    ICD-10 Reference

    Reproduced from the International statistical classification of diseases and related health problems, 10th revision, Fifth edition, 2016. Geneva, World Health Organization, 2016 https://apps.who.int/iris/handle/10665/246208

Symptoms
History of recent or remote wrist injury
Pain and clicking or catching in the wrist
Wrist stiffness and weak grip
Swelling and tenderness over the dorsal radial wrist joint
Pain with axial loading to the wrist
Typical History

The typical patient is a 36-year-old, right-handed male who fell and landed directly on his outstretched right hand after being tripped during a soccer game. After the injury, he experienced pain, stiffness, swelling and tenderness in the injured wrist and had difficulty gripping objects tightly. He assumed he had sprained his wrist from the incident.  A few weeks after his wrist injury the patient started experiencing painful clicking in his wrist while doing forceful repetitive wrist activities.  This prompted the patient to visit his primary care physician for an evaluation. Routine X-rays were negative but a wrist MRI suggested a partial scapholunate interosseous ligament tear. The patient was referred to a hand surgeon for further treatment.

Positive Tests, Exams or Signs
Work-up Options
Images (X-Ray, MRI, etc.)
Scapholunate Tear Imaging
  • Large S-L gap (arrow) on ulnar deviated AP X-ray 4 weeks after a right wrist injury.
    Large S-L gap (arrow) on ulnar deviated AP X-ray 4 weeks after a right wrist injury.
  • S-L gap (arrow) on neutral AP X-ray after a right wrist injury. Note vertical position of the scaphoid , "signet ring sign" ( dashed oval).
    S-L gap (arrow) on neutral AP X-ray after a right wrist injury. Note vertical position of the scaphoid , "signet ring sign" ( dashed oval).
  • Minimal scaphoid (S)-lunate(L) gap on neutral AP X-ray, no gap on radial(R) deviated(D) view and larger gap on ulnar (U) deviated(D) view.
    Minimal scaphoid (S)-lunate(L) gap on neutral AP X-ray, no gap on radial(R) deviated(D) view and larger gap on ulnar (U) deviated(D) view.
  • MRI T1 showing an intact SL ligament (arrow).
    MRI T1 showing an intact SL ligament (arrow).
  • MRI T2 showing an intact SL ligament (arrow).
    MRI T2 showing an intact SL ligament (arrow).
Treatment Options
Treatment Goals
  • Accurately diagnose scapholunate interosseous ligament injury
  • Successfully treat scapholunate interosseous ligament injury
  • Prevent the development of SLAC wrist arthritis
Conservative
  • Immobilization with splint or cast
    • Indicated for acute, undisplaced SLIL injuries
    • Should be followed up with repeat imaging
    • Cast treatment is often insufficient for most patients. 
    • Surgical intervention is frequently necessary unless the ligament is partially torn.7 Unfortunately, anatomic repair that consistently prevents S-L gapping is difficult to achieve.
Operative
  • There are several unresolved issues regarding whether reconstruction or repair should be performed, which is in part related to difficulty in defining what represents acute, subacute and chronic scapholunate interosseous ligament tear pathology.2

 Stage 1: Incomplete tears

  • Non-operative management as described above
  • Athroscopic debridement has shown mixed results

 Stage 2: Complete, repairable tears

  • Ligament is typically avulsed from the scaphoid side, often with a small bone fragment
  • Repair is performed using a small anchor onto the scaphoid
  • Acute repairs can be augmented with capsulodesis or tenodesis with temporary K-wire internal fixation.

Stage 3: Irrepairable tears with normal scaphoid alignment

  • SL reconstruction
  • Stage 3 injuries could theoretically be treated with Bone-Ligament-Bone grafting alone because the secondary scaphoid stabilizers are intact, however many surgeons opt for Stage 4 reconstruction techniques due to more reliable results

Stage 4: Irrepairable tears with a reducible scaphoid malalignment

  • SL reconstruction
  • A variety of techniques have been described, the specifics of which are beyond the scope of this page, but include Brunelli FCR tendon transfer, ECRB tenodesis, Bone-Ligament-Bone grafting, Blatt capsulodesis, Mayo capsulodesis, RASL procedure
  • The scapholunate ligament internal brace 360-degree tenodesis (SLITT) procedure has shown promising results but long term studies have not been established.11

Stage 5: Irreducible scaphoid malalignment without arthritic change

  • Uncommon to catch a patient at this stage prior to arthritic change
  • Theoretically could release adhesions to allow scaphoid to become reducible and then opt for Stage 4 treatment options, but this is technically challenging and has a high rate of failure
  • As such most surgeons typically opt for Stage 6 options

Stage 6: SLAC wrist

  • Salvage options
  • Neurectomies
  • PRC, 4 corner fusions, scaphoidectomy
  • See SLAC wrist page for more details
 
Treatment Photos and Diagrams
Operative Treatment of S-L Tears
  • Scapholunate tear after open reduction and pinning. Scaphoid(S); Lunate(L); Bennett's fracture post ORIF with pins (B).
    Scapholunate tear after open reduction and pinning. Scaphoid(S); Lunate(L); Bennett's fracture post ORIF with pins (B).
  • Open scapholunate acute laceration with transected the extensor tendons. Scaphoid(S); Lunate(L); Cut S-L ligament (arrow).
    Open scapholunate acute laceration with transected the extensor tendons. Scaphoid(S); Lunate(L); Cut S-L ligament (arrow).
  • Open scapholunate acute laceration and cut extensor tendons after surgical repair.
    Open scapholunate acute laceration and cut extensor tendons after surgical repair.
CPT Codes for Treatment Options

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Common Procedure Name
Blatt capsulodesis and/or scapholunate ligament repair
CPT Description
Capsulorrhaphy or reconstruction, wrist, open (e.g. capsulodesis, ligament repair, tendon transfer or graft) (includes synovectomy, capsulotomy and open reduction) for carpal instability
CPT Code Number
25320
CPT Code References

The American Medical Association (AMA) and Hand Surgery Resource, LLC have entered into a royalty free agreement which allows Hand Surgery Resource to provide our users with 75 commonly used hand surgery related CPT Codes for educational promises. For procedures associated with this Diagnostic Guide the CPT Codes are provided above. Reference materials for these codes is provided below. If the CPT Codes for the for the procedures associated with this Diagnostic Guide are not listed, then Hand Surgery Resource recommends using the references below to identify the proper CPT Codes.

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Complications
  • Loss of wrist motion
  • Infection
  • SLAC arthritis
  • Reduced grip strength
Outcomes
  • Acute surgical intervention prior to injury progression is believed to result in improved outcomes, but many patients present in the chronic period, when surgical outcomes may be suboptimal.8  Many acute treatment options leave patients with an early recurrence of their S-L gap.  These gaps may be asymptomatic initially but probably leave the patient at risk for late SLAC wrist arthritis.
  • Reconstructive techniques performed in the chronic setting lead to variable results, and no technique has consistently demonstrated superior outcomes.8
  • Most current treatments fail to reliably maintain reduction of the SL interval and angle at long-term follow-up and have resulted in decreased wrist range of motion and possibly pain.1
  • Patients with risk factors for failure (eg, smoking status, workers’ compensation claim and presenting later than six weeks after injury) should consider reconstructive. intervention with caution because they may have poorer outcomes and require salvage procedures if reconstructive surgery fails.8
Key Educational Points
  • Scapholunate interosseous ligament injuries are frequently missed or dismissed as sprains, which can lead to the development of chronic pain and further degenerative changes.3
  • Increased failure rates have been seen in both complete and partial tears, which suggests that surgical timing maybe important as well as the extent of the tear for predicting success.8
  • Overall, the level of evidence for scapholunaste interosseous ligament injuries injuries is low, and further research is needed to determine the optimal treatment protocol.1,5
  • Many scapholunate interosseous ligament repairs require temporary internal fixation of carpal bone alignment with K-wires.  Some surgeons leave these pins out of the skin to make pin removal easy. Other surgeons leave K-wires temporarily under the skin to decrease the risk of a pin track infection.  Pin tract infections in the wrist can cause a pyrarthrosis of the wrist.
  • The optimal view when evaluating a gap between the scaphoid and lunate after a scapholunate ligament tear is the clenched pencil grip view.14
  • The radioscapholunate ligament (ligament of Testut) originates from the palmar aspect of the distal radius.  This ligament, which is considered a vascular structure more than a stabilizing structure,  inserts onto the palmar aspect of the scapholunate interosseous ligament.
References

Cited

  1. Ward PJ, Fowler JR. Scapholunate Ligament Tears: Acute Reconstructive Options. Orthop Clin North Am 2015;46(4):551-9. PMID: 26410643
  2. Ross M, Loveridge J, Cutbush K, Couzens G. Scapholunate ligament reconstruction. J Wrist Surg 2013;2(2):110-5. PMID: 24436802
  3. Clark DL, von Schroeder HP. Scapholunate ligament injury: the natural history. Can J Surg 2004;47(4):298-9. PMID: 15362336
  4. Luchetti R, Atzei A, Cozzolino R, Fairplay T. Current role of open reconstruction of the scapholunate ligament. J Wrist Surg 2013;2(2):116-25. PMID: 24436803
  5. Pappou IP, Basel J, Deal DN. Scapholunate ligament injuries: a review of current concepts. Hand (NY) 2013;8(2):146-56. PMID: 24426911
  6. Geissler WB, Freeland AE, Savoie FH, et al. Intracarpal soft-tissue lesions associated with an intra-articular fracture of the distal end of the radius. J Bone Joint Surg Am 1996;78(3):357-65. PMID: 8613442
  7. Walsh JJ, Berger RA, Cooney WP. Current status of scapholunate interosseous ligament injuries. J Am Acad Orthop Surg 2002;10(1):32-42. PMID: 11809049
  8. Rohman EM, Agel J, Putnam MD, Adams JE. Scapholunate interosseous ligament injuries: a retrospective review of treatment and outcomes in 82 wrists. J Hand Surg Am 2014;39(10):2020-6. PMID: 25156088
  9. Matson AP, Dekkert TJ, Lampley AJ, Richard MJ, Leversedge FJ, Ruch DS. Diagnosis and arthroscopic management of dorsal wrist capsular impingement. J hand Surg Am. 2017; 42(3): e167-e174.
  10.  Said, J, Baker, K, Fernandez, L, Komatsu, DE, Gould, E, Hurst, LC,: The Optimal Location to Measure Scapholunate Diastasis on Screening Radiographs.  HAND September 2017.  PMID: 28877592
  11. Kakar S, Greene RM. Scapholunate ligament internal brace 360-degree tenodesis (STITT) procedure.  J Wrist Surg 2018; 7(4): 336-340.
  12.  Mayfield JK, Johnson RP, Kilcoyne RK. Carpal dislocations: pathomechanics and progressive perilunar instability. J Hand Surg Am. 1980;5(3):226-241. 
  13.  Garcia-Elas M, Lluch AL, Stanley JK. Three-ligament tenodesis for the treatment of scapholunate dissociation: indications and surgical technique. J Hand Surg Am. 2006;31(1):125-134. 
  14. Lawand A, Foulkes GD. The "clenched pencil" view: a modified clenched fist scapholunate stress view. J Hand Surg Am. 2003;28(3):414-418. 

New Articles

  1. Ward PJ, Fowler JR. Scapholunate Ligament Tears: Acute Reconstructive Options. Orthop Clin North Am 2015;46(4):551-9. PMID: 26410643
  2. Rohman EM, Agel J, Putnam MD, Adams JE. Scapholunate interosseous ligament injuries: a retrospective review of treatment and outcomes in 82 wrists. J Hand Surg Am 2014;39(10):2020-6. PMID: 25156088

Reviews

  1. Pappou IP, Basel J, Deal DN. Scapholunate ligament injuries: a review of current concepts. Hand (NY) 2013;8(2):146-56. PMID: 24426911
  2. Luchetti R, Atzei A, Cozzolino R, Fairplay T. Current role of open reconstruction of the scapholunate ligament. J Wrist Surg. 2013;2(2):116-25. PMID: 24436803

Classics

  1. Berger RA, Blair WF, Crowninshield RD, Flatt AE. The scapholunate ligament. J Hand Surg Am 1982;7(1):87-91. PMID: 7061814
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