SL Ligament (DISI) β SLAC + SNACβ£What constitutes the Scapholunate Ligament?U shape ligament with 3 "sides"3 components - Dorsal (strongest), proximal and palmar componentsβ£What kind of instability does SL injury produce?Due to injury of SL ligament, Lunate extends with Triquetrum resulting in a DISI (Dorsal intercalated segment instability) i.e. Lunate goes dorsallyβ£Special tests for SL injuryScaphoid Shift Test aka Kirk Watson's Test for SL ligamentGrab wrist, thumb on scaphoid tubercleMove patient hand from ulnar to radial deviation whilst maintaining pressure on scaphoid tubercleWith radial deviation, scaphoid usually flexes but this is prevented by the thumb β so the scaphoid subluxes dorsally off the radiusPositive - pain / clickβ£What is the classification for SL injury?Classifx by Stages is clinically useful (Marc Garcia 2006) = 5 questions, 6 stages with (1 pre-dynamic stage)1. partial rupture? = Stage 22. Complete rupture? = stage 33. Is it reduced?4. If dislocated, is it reducible? = Stage 4/55. is there OA? = Stage 6β£Management of SL injury?Dependant on "chronicity and congruity" (very similar to other joint ligament conditions)If < 6 week β K-wire, allow healing of ligamentIf > 6 week, reducible β reconstruct with FCR tendon (brunnelli technique)If > 6 week, irreducible β STT fusionSCENARIO: SLAC WRIST β£What is SLAC Wrist?Progression from SL injury resulting in Lunate extending with Triquetrium to progressive OAβ£How do you classify SLAC [ScaphoLunate Advanced Collapse] wrist?Watson's Classification1 = Radial styloid Scaphoid arthritis2 = + Radio-scaphoid arthritis (due to loss of SL ligament, Scaphoid keeps extending with the LT))3 = + Capitolunate arthritis4 = Pan carpal OAWatsons.pdf296.5KBβ£How to treat SNAC and SLAC wrist (same algorithm)?Dependant on the stage (non op always an option)1 = Radial styloidectomy2 = 4CF or PRC3 = 4CF since CL joint is affected [if PRC then the arthritis capitate joint will articulate with the radius]4 = Wrist Arthrodesisβ£What surgical options before PRC or 4CF?Wrist denervation can be doneOriginal techniques uses 8 approaches to resect all 10 articular nerve branches, Now, it is done via 2 or 3 incisionsSome of the nerves including the terminal branch of PIN between 3 and 4th EC, terminal branches of AIN, terminal branches of SRN. β£Between 4CF and PRC what are the expected ROM and grip strength?PRC - expect poorer weak strength due to shortening of tendons (theoretical)But overall minimal difference - expect ROM 60%, grip strength 80%β£What other fusions you aware of?Limited intercarpal fusionse.g. Lunate capitate fusion - after excision of scaphoid and KIV triquetrium.β£What is 4 corner fusion?Fusion of Capitate, Hamate, Triquetrium and Lunate [HTCL]. usually w scaphoid excisionβ£What is Proximal Row Carpectomy?Capitate will articulate with the radius; so not reccomended if capitolunate joint is already arthriticβ£Any concerns for PRC in young patient? Why?Eventual OA changes Incongruity of the radial lunate fossa with the capitateβ£βΌοΈ 4CF vs PRC for SLAC and SNAC?Mulford JHS 2009 systematic review β no difference in grip strength, function and pain reliefTheoretically, PRC does produce an incongruent joint as capitate head has smaller curvature than lunate (try to avoid in younger)Also, PRC should only be done if no Lunocapitate arthritis β if not the new radiocapitate joint will be arthritic and painful as well.mulford2009.pdf425.1KB