Introduction High energy injury with poor functional outcomes Commonly missed (~25%) on initial presentation Categories perilunate dislocation lunate stays in position while carpus dislocates 4 types transcaphoid-perilunate perilunate transradial-styloid transcaphoid-trans-capitate-perilunar lunate dislocation lunate forced volar or dorsal while carpus remains aligned Mechanism traumatic, high energy occurs when wrist extended and ulnarly deviated leads to intercarpal supination Pathoanatomy sequence of events scapholunate ligament disrupted --> disruption of capitolunate articulation --> disruption of lunotriquetral articulation --> failure of dorsal radiocarpal ligament --> lunate rotates and dislocates, usually into carpal tunnel dislocation can course through greater arc ligamentous disruptions with associated fractures of the radius, ulnar, or carpal bones lesser arc purely ligamentous Anatomy Normal wrist anatomy Osseous proximal row scaphoid lunate triquetrum pisiform distal row trapezium trapezoid capitate hamate Ligaments interosseous ligaments run between the carpal bones scapholunate interosseous ligament lunotriquetral interosseous ligament major stabilizers of the proximal carpal row intrinsic ligaments ligaments the both originate and insert among the carpal bones dorsal intrinsic ligaments volar intrinsic ligaments extrinsic ligaments connect the forearm bones to the carpus volar extrinsic carpal ligaments dorsal extrinsic carpal ligaments Classification Mayfield Classification Stage I • scapholunate dissociation Stage II • + lunocapitate disruption Stage III • + lunotriquetral disruption, "perilunate" Stage IV • lunate dislocated from lunate fossa (usually volar) • associated with median nerve compression Presentation Symptoms acute wrist swelling and pain median nerve symptoms may occur in ~25% of patients most common in Mayfield stage IV where the lunate dislocates into the carpal tunnel Imaging Radiographs required views PA/lateral wrist radiographs findings AP break in Gilula's arc lunate and capitate overlap lunate appears triangular "piece-of-pie sign" lateral loss of colinearity of radius, lunate, and capitate SL angle >70 degrees MRI usually not required for diagnosis Treatment Nonoperative closed reduction and casting indications no indications when used as definitive management outcomes universally poor functional outcomes with non-operative management recurrent dislocation is common Operative emergent closed reduction/splinting followed by open reduction, ligament repair, fixation, possible carpal tunnel release indications all acute injuries <8 weeks old outcomes emergent closed reduction leads to decreased risk of median nerve damage decreased risk of cartilage damage return to full function unlikely decreased grip strength and stiffness are common proximal row carpectomy indications chronic injury (defined as >8 weeks after initial injury) not uncommon, as initial diagnosis frequently missed total wrist arthrodesis indications chronic injuries with degenerative changes Techniques Closed Reduction technique finger traps, elbow at 90 degrees of flexion hand 5-10 lbs traction for 15 minutes dorsal dislocations are reduced through wrist extension, traction, and flexion of wrist apply sugar tong splint follow with surgery Open reduction, ligament repair and fixation +/- carpal tunnel release approach (controversial) dorsal approach longitudinal incision centered at Lister's tubercle excellent exposure of proximal carpal row and midcarpal joints does not allow for carpal tunnel release volar approach extended carpal tunnel incision just proximal to volar wrist crease combined dorsal/volar pros added exposure easier reduction access to distal scaphoid fractures ability to repair volar ligaments carpal tunnel decompression cons some believe volar ligament repair not necessary increased swelling potential carpal devascularization difficulty regaining digital flexion and grip technique fix associated fractures repair scapholunate ligament suture anchor fixation protect scapholunate ligament repair controversy of k-wire versus intraosseous cerclage wiring repair of lunotriquetral interosseous ligament decision to repair based on surgeon preference as no studies have shown improved results post-op short arm thumb spica splint converted to short arm cast at first post-op visit duration of casting varies, but at least 6 weeks Proximal row carpectomy technique perform via dorsal and volar incisions if median nerve compression is present volar approach allows median nerve decompression with excision of lunate dorsal approach facilitates excision of the scaphoid and triquetrum
QUESTIONS 1 of 5 1 2 3 4 5 Previous Next Sorry, this question is for Virtual Curriculum Members Only Click here to purchase Sorry, this question is for Virtual Curriculum Members Only Click here to purchase (OBQ09.227) A 35-year-old professional football player complains of severe wrist pain after making a tackle. He reports paresthesias in his thumb and index finger. AP and lateral radiographs of the wrist are shown in figures A and B respectively. What is the most appropriate next step in management? Review Topic QID: 3040 FIGURES: A B 1 short arm thumb spica cast 2% (49/2784) 2 long arm thumb spica cast 1% (14/2784) 3 urgent closed reduction and splinting 95% (2642/2784) 4 MR arthrogram of the wrist to assess ligamentous injuries 2% (65/2784) 5 bone scan to assess vascularity 0% (2/2784) Select Answer to see Preferred Response PREFERRED RESPONSE 3 Sorry, this question is for Virtual Curriculum Members Only Click here to purchase Sorry, this question is for Virtual Curriculum Members Only Click here to purchase
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