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SLAC & SNAC wrists Management & Results. Satyam Patel January 19th, 2007. Overview. Definitions Natural history Treatment Options Results. SLAC = Scapho-Lunate Advanced Collapse SNAC = Scaphoid Nonunion Advanced Collapse PRC = proximal row carpectomy
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SLAC & SNAC wristsManagement & Results Satyam Patel January 19th, 2007
Overview • Definitions • Natural history • Treatment Options • Results
SLAC = Scapho-Lunate Advanced Collapse SNAC = Scaphoid Nonunion Advanced Collapse PRC = proximal row carpectomy 4CF = 4 corner (Capito-Hamate-Lunate-Triquetrum) Fusion Definition
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
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) Biomechanical basis for treatment
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
Technique 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
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, ROM 4CF 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 & 200211% 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
Technique 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
Results Krakauer et al, 1994 Wyrick et al, 1995 Tomaino et al, 1994