Elsevier

The Journal of Hand Surgery

Volume 33, Issue 6, July–August 2008, Pages 998-1013
The Journal of Hand Surgery

Current concept
Scapholunate Instability: Current Concepts in Diagnosis and Management

https://doi.org/10.1016/j.jhsa.2008.04.027Get rights and content

Injuries to the scapholunate joint are the most frequent cause of carpal instability and account for a considerable degree of wrist dysfunction, lost time from work, and interference with activities. The complex arrangement and kinematics of the 2 rows of carpal bones allows for an enormous degree of physiologic motion, and a hierarchy of primary and secondary ligaments serves to balance an inherently unstable structure. Although insufficient to cause abnormal carpal posture or collapse on static radiographs, an isolated injury to the scapholunate interosseous ligament may be the harbinger of a relentless progression to abnormal joint mechanics, cartilage wear, and degenerative change. Intervention for scapholunate instability is aimed at arresting the degenerative process by restoring ligament continuity and normalizing carpal kinematics. In this review, we discuss the anatomy, kinematics, and biomechanical properties of the scapholunate articulation and provide a foundation for understanding the spectrum of scapholunate ligament instability. We propose an algorithm for treatment based on the stage of injury, degree of secondary ligamentous damage, and arthritic change.

Section snippets

Anatomy

The clustering of the 8 small carpal bones into proximal and distal carpal rows has been widely accepted, based on their kinematic behavior during global wrist motion. The 4 bones of the distal carpal row (trapezium, trapezoid, capitate, and hamate) are tightly bound to one another via stout intercarpal ligaments, and motion between them can be considered negligible. Similarly, the nearly rigid ligamentous connection of the trapezium and capitate to the index and middle metacarpals and lack of

Wrist Mechanics

As the anterior cruciate ligament is considered the primary stabilizer of the knee, so too can the SLIL be considered the primary stabilizer of the scapholunate joint, if not the entire carpus. It is surrounded in turn by several secondary stabilizers, each insufficient to cause instability after isolated disruption, but each important in the maintenance of normal scapholunate kinematics, and vulnerable to attritional wear after complete disruption of the SLIL. On the volar-radial side are the

Definition

Classically, the diagnosis of scapholunate instability was predicated on abnormal scaphoid or lunate alignment as seen on static radiographs (Fig. 5).23 This definition, however, was not inclusive enough to explain the often disabling symptoms of pain with mechanical loading or sudden shifts or “clunks” that were noted among some injured patients with normal radiographs. The concept of dynamic scapholunate instability was proposed to describe abnormal carpal positioning that required special

Classification (Table 1)51

The mildest form of scapholunate instability, or occult instability, is usually initiated by a fall on the outstretched hand that may only cause a tear or attenuation of a portion of the scapholunate interosseous ligament, with or without a disruption of the ligament of Testut.27 Patients with this injury may not seek treatment initially, have no abnormalities of scaphoid or lunate posture on static or stress radiographs, and have wrist pain or dysfunction with mechanical loading. Fluoroscopic

Dorsal Intercalated Segment Instability

Massive ligament disruption at the time of injury, as may occur in perilunate or lunate dislocations, or gradual attrition of the secondary extrinsic stabilizers leads to abnormal extension of the lunate and carpal collapse after scapholunate dissociation. The combined effects of an extension moment transmitted through the intact triquetrolunate ligament and coupled dorsal translation of the capitate force the lunate into extension and exacerbate the abnormal posture of the scapholunate joint.

Scapholunate Advanced Collapse Wrist

In the earliest stage of the SLAC wrist deformity, degenerative changes are limited to an area of abnormal contact between the abnormally rotated scaphoid and the radial styloid. Radial styloidectomy will not alter the progression of the degenerative process at this stage, and any degree of pain relief is generally regarded as temporary. The scaphoid remains rotated into palmar flexion and its contact area with the radius remains reduced and shifted dorsally. Persistent abnormal load transfer

References (96)

  • J. Ishikawa et al.

    The effects of wrist distraction on carpal kinematics

    J Hand Surg

    (1999)
  • H. Moritomo et al.

    2007 IFSSH committee report of wrist biomechanics committee: biomechanics of the so-called dart-throwing motion of the wrist

    J Hand Surg

    (2007)
  • F.W. Werner et al.

    Scaphoid and lunate motion during a wrist dart throw motion

    J Hand Surg

    (2004)
  • S.W. Wolfe et al.

    The dart-throwing motion of the wrist: is it unique to humans?

    J Hand Surg

    (2006)
  • A.K. Palmer et al.

    Functional wrist motion: a biomechanical study

    J Hand Surg

    (1985)
  • A.D. Blevens et al.

    Radiocarpal articular contact characteristics with scaphoid instability

    J Hand Surg

    (1989)
  • T.D. Meade et al.

    Radiographic analysis of selective ligament sectioning at the carpal scaphoid: a cadaver study

    J Hand Surg

    (1990)
  • R.L. Linscheid et al.

    Treatment of scapholunate dissociationRotatory subluxation of the scaphoid

    Hand Clin

    (1992)
  • F.W. Werner et al.

    Severity of scapholunate instability is related to joint anatomy and congruency

    J Hand Surg

    (2007)
  • H. Watson et al.

    Rotary subluxation of the scaphoid: a spectrum of instability

    J Hand Surg

    (1993)
  • R. Nathan et al.

    Rotatory subluxation of the scaphoid revisited

    Hand Clin

    (2000)
  • M. Garcia-Elias et al.

    Definition of carpal instability

    J Hand Surg

    (1999)
  • S.W. Wolfe et al.

    Kinematics of the scaphoid shift test

    J Hand Surg

    (1997)
  • S.M. Schimmerl-Metz et al.

    Radiologic measurement of the scapholunate joint: implications of biologic variation in scapholunate joint morphology

    J Hand Surg

    (1999)
  • G.P. Cautilli et al.

    Scapho-lunate distance and cortical ring sign

    J Hand Surg

    (1991)
  • S. Yamaguchi et al.

    The carpal stretch test at the scapholunate joint

    J Hand Surg

    (1998)
  • K.C. Chung et al.

    Wrist arthrography versus arthroscopy: a comparative study of 150 cases

    J Hand Surg

    (1996)
  • R.M. Cantor et al.

    The relevance of ligament tears or perforations in the diagnosis of wrist pain: an arthrographic study

    J Hand Surg

    (1994)
  • T.J. Herbert et al.

    Bilateral arthrography of the wrist

    J Hand Surg

    (1990)
  • B. Bille et al.

    A comparison of CT arthrography of the wrist to findings during wrist arthroscopy

    J Hand Surg

    (2007)
  • R.A. Berger et al.

    Magnetic resonance imaging of the anterior radiocarpal ligaments

    J Hand Surg

    (1994)
  • M. Schädel-Höpfner et al.

    MRI versus arthroscopy in the diagnosis of scapholunate ligament injury

    J Hand Surg

    (2001)
  • M.B. Rotman et al.

    Scaphocapitolunate arthrodesis

    J Hand Surg

    (1993)
  • D.S. Ruch et al.

    Arthroscopic assessment of carpal instability

    Arthroscopy

    (1998)
  • S.W. Wolfe

    Scapholunate instability

    J Am Soc Surg Hand

    (2001)
  • J.K. Mayfield et al.

    Carpal dislocations: pathomechanics and progressive perilunar instability

    J Hand Surg

    (1980)
  • H. Watson et al.

    The SLAC wrist: scapholunate advanced collapse pattern of degenerative arthritis

    J Hand Surg

    (1984)
  • S.L. Moran et al.

    Capsulodesis for the treatment of chronic scapholunate instability

    J Hand Surg

    (2005)
  • A.P.C. Weiss et al.

    Arthroscopic debridement alone for intercarpal ligament tears

    J Hand Surg

    (1997)
  • D.S. Ruch et al.

    Arthroscopic management of partial scapholunate and lunotriquetral injuries of the wrist

    J Hand Surg

    (1996)
  • G. Blatt

    Capsulodesis in reconstructive hand surgeryDorsal capsulodesis for the unstable scaphoid and volar capsulodesis following excision of the distal ulna

    Hand Clin

    (1987)
  • R.R. Slater et al.

    Dorsal intercarpal ligament capsulodesis for scapholunate dissociation: biomechanical analysis in a cadaver model

    J Hand Surg

    (1999)
  • C.J. Lavernia et al.

    Treatment of scapholunate dissociation by ligamentous repair and capsulodesis

    J Hand Surg

    (1992)
  • V.K. Gajendran et al.

    Long-term outcomes of dorsal intercarpal ligament capsulodesis for chronic scapholunate dissociation

    J Hand Surg

    (2007)
  • B.I. Wintman et al.

    Dynamic scapholunate instability: results of operative treatment with dorsal capsulodesis

    J Hand Surg

    (1995)
  • J. Pomerance

    Outcome after repair of the scapholunate interosseous ligament and dorsal capsulodesis for dynamic scapholunate instability due to trauma

    J Hand Surg

    (2006)
  • A.P.C. Weiss

    Scapholunate ligament reconstruction using a bone-retinaculum-bone autograft

    J Hand Surg

    (1998)
  • S.J. Svoboda et al.

    Autografts from the foot for reconstruction of the scapholunate interosseous ligament

    J Hand Surg

    (1995)
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