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WRIST OSTEOARTHRITIS (SLAC WRIST)

Introduction

Nearly 90% of the degenerative changes observed in patients with osteoarthritis of the wrist follow three predictable patterns, the most common of which is “scapholunate advanced collapse (SLAC)” wrist, coined by Watson and Ballet in 1984.1 Arthritic changes initially involve the radioscaphoid joint, and as cartilage disappears, the radial side of the wrist loses support. The capitate slides away from the radial side of the lunate, which in turn, leads to degeneration of the capitolunate joint and the hamatolunate joint. The radiolunate and lunotriquetral joints are often spared. The trapeziometacarpal joint is usually affected by arthritis that is unrelated to the SLAC wrist process.

Pathophysiology

  • Rotary subluxation of the scaphoid is the prominent etiology, followed by scaphoid nonunion. Other conditions that will produce SLAC wrist include Presier’s disease, midcarpal instability and intra-articular fractures involving the radioscaphoid or capitolunate joints.
  • Watson stages:
    • Stage I: osteoarthritis between scaphoid and radial styloid
    • Stage II: osteoarthritis between scaphoid and entire scaphoid facet of the radius
    • Stage III: osteoarthritis between capitate and lunate

Related Anatomy

  • Scaphoid
  • Radial styloid
  • Capitate
  • Lunate
  • Capitolunate joint
  • Hamatolunate joint

Incidence and Related Conditions

  • SLAC wrist affects people aged 19–82 years and most often manifests in the dominant wrist; it is more common in men than in women and more common in manual laborers.
  • Most SLAC wrist surgeries are performed on people in their 40s.

Differential Diagnosis

  • Scaphoid fracture
  • Scapholunate dissociation
  • Distal radius fracture
  • de Quervain’s disease
  • Kienböck’s disease
Clinical Presentation Photos and Related Diagrams
  • Scapholunate Advanced Collapse (SLAC) with dorsal radial Synovitis (see arrow) (Hover over right edge to see more images)
    Scapholunate Advanced Collapse (SLAC) with dorsal radial Synovitis (see arrow) (Hover over right edge to see more images)
  • SLAC Wrist lateral view with dorsal radial Synovitis (see arrow)
    SLAC Wrist lateral view with dorsal radial Synovitis (see arrow)
Pathoanatomy Photos and Related Diagrams
  • SLAC Wrist with gap between Scaphoid and Lunate secondary to chronic S-L ligament rupture
    SLAC Wrist with gap between Scaphoid and Lunate secondary to chronic S-L ligament rupture
  • Note the damaged cartilage and solar edges
    Note the damaged cartilage and solar edges
Symptoms
• Pain localized to scapholunate interval
• Wrist stiffness with dorsal radial swelling
• Progressive weakness in affected hand
• Difficulty bearing weight across affected wrist
Typical History

Many patients with SLAC wrist will have minimal symptoms and present because of a secondary problem, such as carpal tunnel syndrome. Patients may have variable levels and durations of wrist pain during activity, and they will relate their symptoms to increased activity and overuse. Post-activity pain may be present. Many patients use NSAIDs for pain relief. The patients may or may not have a history of antecedent recent or past trauma to the wrist. The typical patient will frequently be a late middle aged male who does heavy mechanical work. Often the patient will not recall trauma to the wrist.

Positive Tests, Exams or Signs
Dorsal Tenosynovitis
Hyperligamentous Laxity
Range of Motion: Active
Range of Motion: Passive
Scaphoid Tenderness
Scapholunate (S-L) Tenderness
Watson Scaphoid Shift Test
Extensor Tendon Exam
Grip Strength
Work-up Options
Radiology studies - arthrogram
Radiology studies - stress X-rays
Radiology studies - X-ray
Radiology studies - fluoroscopy
Magnetic resonance imaging - MRI without contrast
Images (X-Ray, MRI, etc.)
  • MiniFlouroscopy is an excellent device for identifying scapholunate gaps secondary to S-L ligament tears.
    MiniFlouroscopy is an excellent device for identifying scapholunate gaps secondary to S-L ligament tears. (Hover over right edge to see more images)
  • Large static scapholunate gap (Red Circle)
    Large static scapholunate gap (Red Circle)
  • Scaphoid nonunion with early arthritis at radioscaphoid joint (non-stress view).
    Scaphoid nonunion with early arthritis at radioscaphoid joint (non-stress view).
  • Scaphoid nonunion with early arthritis at radioscaphoid joint and S-L tear (stress view).
    Scaphoid nonunion with early arthritis at radioscaphoid joint and S-L tear (stress view).
  • SLAC Wrist with S-L gap(1), OA radioscaphoid joint(2),&OA Lunocapitate joint(3)
    SLAC Wrist with S-L gap(1), OA radioscaphoid joint(2),&OA Lunocapitate joint(3)
Treatment Options
Conservative: 
  • Early-stage/mild diseasewith mild symptoms: NSAIDs, wrist splinting, possible corticosteroid injections
Operative: 
  • Stage I
    • Radial styloidectomy and scaphoid stabilization (open or arthroscopic)
    • Posterior interosseous nerve (PIN) and anterior interosseous nerve (AIN) denervation
  • Stage II
    • Proximal row carpectomy
    • Scaphoid excision and four corner fusion
  • Stage III
    • Scaphoid excision and four corner fusion
    • Wrist fusion
Treatment Photos and Diagrams
  • SLAC Wrist with radioscaphoid joint narrowing and osteophyte at 1 with normal cartilage at 2 and 3
    SLAC Wrist with radioscaphoid joint narrowing and osteophyte at 1 with normal cartilage at 2 and 3
  • Incision plan for proximal row carpectomy in patient with SLAC wrist
    Incision plan for proximal row carpectomy in patient with SLAC wrist
  • Screw in scaphoid used to manipulate bone while ligaments cut.
    Screw in scaphoid used to manipulate bone while ligaments cut.
  • Lunate (arrow) at capitate-lunate joint.
    Lunate (arrow) at capitate-lunate joint.
  • Lunate removed during primal row carpectomy
    Lunate removed during primal row carpectomy
  • Proximal row excised completely. Traction views (A&B) and capitate in lunate fossa (C).
    Proximal row excised completely. Traction views (A&B) and capitate in lunate fossa (C).
  • Patient with bilateral SLAC wrists with degenerative changes in radioscaphoid and capitate-lunate joints.
    Patient with bilateral SLAC wrists with degenerative changes in radioscaphoid and capitate-lunate joints.
  • Surgical plan for scaphoid excision and 4 corner fusion
    Surgical plan for scaphoid excision and 4 corner fusion
  • Do not remove the polar 10-15% of the cartilage.
    Do not remove the polar 10-15% of the cartilage.
  • Scaphoid excised, bone graft in place and fusion secured with four "65" K-wires which will be removed at 6-8 weeks.
    Scaphoid excised, bone graft in place and fusion secured with four "65" K-wires which will be removed at 6-8 weeks.
  • Solid 4 Corner Fusion at four months with cartilage between radius and lunate
    Solid 4 Corner Fusion at four months with cartilage between radius and lunate
  • Four corner fusion done with screws
    Four corner fusion done with screws
  • Four corner fusion done with broken (arrow) screw
    Four corner fusion done with broken (arrow) screw
Complications
  • Nonunion, de Quervain’s disease, dystrophy, predystrophy
Outcomes
  • AIN/PIN: 59–70% of patients report improvements; minimal effects on ROM.2
  • Proximal row carpectomy: wrist ROM was 63% and grip strength was 83–91% of the contralateral side; objective findings did not correlate with patient satisfaction or wrist pain. Overall, long-term results can be poor, and alternatives should be considered for younger patients and manual laborers.2
  • Four-corner arthrodesis: postoperative ROM was 56% and grip strength was 76–80% of contralateral side; 92–95% had bony fusion and 12% required total arthrodesis.2
Video
Stress Testing Scapholunate ligament under MiniFlouroscopy. Note widening S-L joint (Red Circle)
Key Educational Points
  • SLAC is a pattern of carpal degenerative changes that spare the radiolunate facet.
  • The styloscaphoid, radioscaphoid and capitolunate joints are affected by SLAC wrist arthritic changes.
  • The radiolunate joint is spared arthritic changes.
Practice and CME
References

Cited

  1. Watson HK, Ballet FL. The SLAC wrist: scapholunate advanced collapse pattern of degenerative arthritis. J Hand Surg Am 1984;9(3):358-65. PMID: 6725894
  2. Shah CM, Stern PJ. Scapholunate advanced collage (SLAC) and scaphoid nonunion advanced collapse (SNAC) wrist arthritis. Curr Rev Musculoskelet Med 2013;6:9-17. PMID: 23325545

New Articles

  1. Cobb TK, Walden AL, Wilt JM. Arthroscopic Resection Arthroplasty of the Radial Column for SLAC Wrist. J Wrist Surg 2014;3(2):114-22. PMID: 25032077
  2. Chang IY, et al. Kienbock's disease and scapholunate advanced collapse. Orthopedics 2014;37(9):578, 637-9. PMID: 25198349

Reviews

  1. Crema MD, et al. Scapholunate advanced collapse and scaphoid nonunion advanced collapse: MDCT arthrography features. Am J Roentgenol 2012;199(2):W202-7. PMID: 22826422
  2. Strauch RJ. Scapholunate advanced collapse and scaphoid nonunion advanced collapse arthritis--update on evaluation and treatment. J Hand Surg Am 2011;36(4):729-35. PMID: 21463735

Classics

  1. Fassler PR, Stern PJ, Kiefhaber TR. Asymptomatic SLAC wrist: does it exist? J Hand Surg Am 1993;18(4):682-6. PMID: 8349981
  2. Watson HK, Ballet FL. The SLAC wrist: scapholunate advanced collapse pattern of degenerative arthritis. J Hand Surg Am 1984;9(3):358-65. PMID: 6725894