slac & snac wrists management & results satyam patel january 19th, 2007
TRANSCRIPT
SLAC & SNAC wristsManagement & Results
Satyam PatelJanuary 19th, 2007
Overview
• Definitions• Natural history • Treatment Options• Results
Definition
• SLAC = Scapho-Lunate Advanced Collapse
• SNAC = Scaphoid Nonunion Advanced Collapse
• PRC = proximal row carpectomy• 4CF = 4 corner (Capito-Hamate-
Lunate-Triquetrum) Fusion
Natural History
• Ligament disruption– Scapholunate– Radioscaphoid
Natural History
• Scaphoid flexes abnormally
Natural History
• Increased contact– Proximal pole + scaphoid fossa– Distal pole + radial styloid
– Arthritic changes
Natural History
• DISI deformity develops– Lunate and triquetrum extend
Natural History
• Capitate migrates into scapholunate interval
• Midcarpal arthritis at capitolunate articulation
Natural History
• SLAC wrist– Scapholunate advanced collapse
– Constellation of findings• DISI• Radioscaphoid arthritis• Midcarpal arthritis• Sparing of radiolunate joint• Carpal collapse
Natural History
• SLAC wrist– Scapholunate advanced
collapse
• I radial styloid + distal pole scaphoid
• II scaphoid fossa + proximal pole
• III capitolunate
Radioscaphoid
Midcarpal
Natural History
• SLAC wrist– Scapholunate advanced collapse
• I radial styloid + distal pole scaphoid• II scaphoid fossa + proximal pole• III capitolunate
Natural History
• SLAC wrist– Scapholunate advanced
collapse
• I radial styloid + distal pole scaphoid
• II scaphoid fossa + proximal pole
• III capitolunate
SNAC - Natural History• Scaphoid nonunion leads to a series of degenerative changes that
are similar to SLAC.• In general
– 1 decade after fracture - scaphoid nonunion cystic changes– 2 decades - radioscaphoid degeneration– 3 decades - pancarpal arthritis
• Stage I - radial styloid - scaphoid joint• Stage II - degeneration of radioscaphoid and scaphocapitate
joints• Stage III - capitolunate degeneration• (proximal radioschaphoid and radiolunate joints are relatively well
preserved)
Treatment Options
• Relevant factors– Patient age– Activity Level– State of Degeneration
Treatment Options
• Conservative– Activity modification– Splinting– Steroid injection– NSAIDs
Treatment Options
• Surgical– PIN neurectomy– Total or partial wrist arthrodesis– Proximal row carpectomy– Distraction arthroplasty– Total wrist arthroplasty
Biomechanical basis for treatment
4-CF (+scaphoid excision)
• Wrist motion occurs through preserved radiolunate and ulnocarpal joints
• Including hamate and triquetrum increases fusion rate without sacrificing further motion
• CI’s = radiolunate degeneration, ulnar carpal translation
PRC
• Capitate articulates with lunate fossa
• Difference in arc of rotation between C & L allows for radial and ulnar deviation
• Preserving radio-scapho-capitate ligament is important for stability (N.B. if doing styloidectomy)
Irreducible Carpus And Arthritis
• RECALL:• SLAC wrist
– Scapholunate advanced collapse• I radial styloid + distal pole scaphoid• II scaphoid fossa + proximal pole• III capitolunate
Irreducible Carpus And Arthritis
• I– Radial styloidectomy +/- scaphoid fixation & bone graft
• II– Proximal row carpectomy– 4 corner fusion +/- radial styloidectomy / scaphoid excision
• III– 4 corner fusion with scaphoid excision or arthrodesis
• Proximal row carpectomy unsuitable due to midcarpal OA
Irreducible Carpus And Arthritis
• I– Radial styloidectomy
• Removes arthritic joint• Does not prevent progression to stage II and III
Irreducible Carpus And Arthritis
• II– Proximal row carpectomy
• Converts wrist into ball and socket joint• Mismatching radiocapitate joint allows translation• Removal of arthritic joints while motion maintained
Irreducible Carpus And Arthritis
• II - SLAC wrist procedure– Four corner fusion (capitate-lunate-hamate-triquetrum)– Scaphoid excision– Removes arthritic joints– Makes use of preserved radiolunate joint– Higher loss of motion, strength maintained
Irreducible Carpus And Arthritis
• III– SLAC wrist procedure
• Proximal row carpectomy not suitable due to midcarpal arthritis
Indications for total wrist arthrodesis
• Diffuse arthritic change (capitate or lunate fossa involved)
• Motion less than 30 / 30
• Contraindication = if wrist dorsiflexion is required for tenodesis (e.g. tetraplegic patients)
PRC - Technique
• Longitudinal incision through EPL sheath
• Capsulotomy• Excise lunate first• Then triquetrum and scaphoid
via sharp dissection to preserve ligaments.
• +/- radial styloidectomy• Dorsal capsular repair• 2-3/52 in cast
PRC - variations
• Pre-op arthroscopy to evaluate condition of cartilage• Temporary internal fixation with K-wires• dorsal capsule interposition• Radial styloidectomy• Proximal capitate excision (?)
• N.B. caution in pts < 35 y.o., rheumatoid patients
SLAC Wrist ProcedureFour-Corner-Fusion With Scaphoid Excision
• Exposure as in PRC• Scaphoid excision• Radioscaphocapitate ligament preserved• Joints decorticated• ICBG or distal radius bone graft• Lunate reduced to capitate (slight flexion)• K-wires, staples, screws, “spider” plate• Avoid silastic scaphoid (synovitis)• 6/52 – 8/52 cast
Technique
Variations of 4 -corner fusion
• Use of k-wires vs. use of spider plate– Trade-off between increased fusion rate and incidence of
dorsal impingement– P. Stern
• Excision of triquetrum (3 corner fusion / Capito-lunate fusion)– Better dorsiflexion in cadaveric study, no significant increase
in ROM clinically thus far.– G. Bain, J. Calandruccio, R. Gelberman
Salvage
• Total wrist fusion– All arthritic joints fused– (radius - 3rd MC axis
mandatory, others optional)– No motion / good strength
Results
• Limited fusions– STT
• 14% nonunion (385 cases from multiple series)• Pain relief unpredictable• Add styloidectomy if impingement present
– SL• 50% nonunion
– SLC• 50% decrease in wrist motion• 4/11 required total wrist fusion
Results
Degenerative Arthritis of the Wrist : Proximal Row Carpectomy versus Scaphoid excision and four-corner arthrodesis.M. Cohen S. Kozin J. Hand Surg. 2001 26A:94-104
2 cohorts of 19 patients each largely stage 2 arthritis, most SLAC, 3 SNAC in one arm 6 in the other.
- Early follow-up results (DASH, SF-36)No significant differences in pain, grip strength, ROM4CF group scored higher on mental-health component of SF-36 and
retained a slightly greater radial-ulnar deviation arc.
Results
• Acta Orthop Belg 2006– Salvage procedures for degenerative osteoarthritis of
the wrist due to advanced carpal collapse– 63 patients - 19 fused, PRC 26, scaphoidectomy
+4CF 18– PRC significantly better (DASH =16)– No significant differences between 4CF and
arthrodesis (DASH = 39, 45)
PRC - results
• Jorgenson 22 PRC cases over 20 years• Increased ROM, subjective feeling of weakness
• Scand J Plast Reconstr Surg & Hand Surg 2006• 51 patients PRC between 1992 & 2002
11% required arthrodesis (9 patients)• 34 returned to work (avg. 6/12)• F 66% E 73% RD 74% UD 76%• Grip 70%
Results of 4CF & scaphoidectomy
• Ashmead et. al • 44/12 100 patients• E 32deg F 42deg (53%)• Grip strength 80%• 78/85 satisfied (would undergo operation again)• 3% nonunion rate• Dorsal impingement 13%
Results
• Wrist fusion– 85% total pain relief– 65% return to former occupation
Hastings and Silver
Summary: No Arthritis
• Reducible + adequate ligament– Reduction, repair, pinning
• Reducible + inadequate ligament– Soft tissue vs. bony procedure
• Irreducible– Treat as SLAC wrist vs. Limited fusion (STT)
Next page
Summary: Arthritic Wrist
• Stage I– Radial styloidectomy
• Stage II– Proximal row carpectomy: maintain motion, fast recovery– Four corner fusion + scaphoidectomy : strength ?
• SLAC III– Four corner fusion + scaphoidectomy
• Salvage– Wrist fusion
Irreducible Carpus Without Arthritis
• Why is it not reducible?– Fibrous tissue in joints– Deformed articular surfaces– Ligament shortening and laxity
• Solution– Remove fibrous tissue from joints– Remove deformed articular surfaces– Remove lax / stiff ligaments
• Limited carpal fusion•Removes intraarticular block to reduction•Fixes reduced scaphoid position to carpus•Prevents further carpal collapse•Spares uninvolved joints
Irreducible Carpus Without Arthritis
• STT fusion + dorsolateral styloidectomy• SL / SC / SLC fusion
• Without reduction of deformity, progression to SLAC wrist• Results of limited wrist carpal fusions may not be good enough or
predictable enough to justify using them -- safer option is to treat as SLAC wrist
STT Fusion• Transverse dorsal incision• Retract superficial radial n. and v.• Open retinaculum along EPL• B/w ECRL and ECRB• Open STT• Open radioscaphoid joint
– If arthritic go to SLAC wrist reconstruction• Reduce scaphoid and fix to carpus• Remove STT joint preserving height• Distal radius graft• 3 x 0.045 K-wires across STT
Technique
ResultsPRC SLAC
procedureROM maintained
64% 45%
Grip strength 75% 75%
Pain relief “good” “good”
Satisfaction “good” “good”
Failure rate 20%, 0 0-7%, 30% Krakauer et al, 1994Wyrick et al, 1995Tomaino et al, 1994