Wrist Fractures:

• Scaphoid fractures = 60% of carpal bone fractures  second most commonly fractured bone in the upper extremity (after the distal radius)
• 10-20% occur at proximal pole: highest incidence of avascular necrosis  distal pole has best blood supply due to retrograde flow
• Surgical intervention for humpback deformity if intrascaphoid angle > 45 degrees (normal = 30-40 degrees)
• Peak incidence in men ages 20-24

• Anatomy:
• 80% of scaphoid is articular cartilage
• Dorsal scaphoid branch of radial artery  supplies 70-80% of the scaphoid
• Volar scaphoid branch of the radial artery (comes from radial artery or superficial palmar branch)  enters at distal tubercle and supplies distal 20-30% of scaphoid
• Scaphoid links proximal and distal carpal rows
• Long axis of bone is tilted volar and radial relative to long axis of the limb
• Palmar approach: for distal pole and waist fractures
• Dorsal approach: proximal pole fractures
• Management:
• Thumb spica x8-12 weeks for acute, non-displaced, stable scaphoid fractures 
• Even if not seen on xray if high suspicion
• Some studies say 6 weeks of above elbow immobilization first to eliminate rotational forces on the scaphoid
• MRI: imaging modality of choice to characterize scaphoid fractures  better than CT
• Operative Management:
• Displacement of >1mm in any view
• Xrays:
• Scaphoid view: ulnar deviation and wrist extension
• Scaphoid non-union:
• Incidence is between 4-50% 
• Failure of the fracture to heal within 6 months
• Decreased wrist extension, pain at snuffbox and scaphoid tubercle
• Russe procedure: iliac cancellous bone grafts
• Vascularized bone graft: 1,2 intercompartmental supraretinacular artery
• Located between first and second dorsal compartments, superficial to the extensor retinaculum
• Medial femoral condyle: descending genicular artery (br. of SFA) located posterior to the vastus medialis and anterior to the adductor tendon
• Salvage procedures:
• Limited intercarpal fusion
• PRC
• Scaphoid excision + 4 corner fusion
• Total wrist fusion
• Triquetral fracture:
• Most are dorsal ridge avulsion fractures  cast immobilization x4 weeks (seen on lateral view)
• Second most commonly fractured carpal bone
• Hamate: usually golfers/tennis/baseball from repeated stress
• Fracture of hook of hamate -> hypothenar tenderness
• Seen on carpal tunnel xray view

• Scapholunate Ligament: C shaped and contains dorsal, volar, and membranous portions.
• Dorsal is the thickest, strongest (true ligament) with transversely oriented fibers
• Important secondary stabilizers include RSC (radioscaphocapitate), LRL (long radiolunate), SRL (short radiolunate) and STT (scaphotrapeziotrapezoid) as well as dorsal structures DRC (dorsal radiocarpal) and DIC (dorsal intercarpal) ligaments 
• Scapholunate Dissociation (SLD):  most common form of carpal instability
• Mechanism: axial loading a wrist that is 1) extended 2) ulnarly deviated 3) and in intracarpal supination
• Presenting Symptoms: pain over SL (1cm distal to listers); can have positive Watsons (or scaphoid shift test), painful clunking or clicking

i. Scaphoid (Watson) shift maneuver (for scapholunate ligament tear):  Place examiner’s thumb on the palmar surface of the patient’s distal pole of the scaphoid–>Place the examiner’s index finger over the dorsal surface of the scapholunate joint–> Passively move the patient’s wrist from ulnar deviation to radial deviation while applying a dorsally directed force on the distal pole of the scaphoid–> A positive response is dorsal pain with detection of dorsal subluxation of the proximal pole of the scaphoid, out of the scaphoid fossa of the radius (the clunk) 
 

• Specific x-ray findings:
• Perfect scapholunate view is 10 degree hyperpronation
• Best test for dynamic SL injury is clenched fist view
• Remember that the scapholunate interval may appear normal on X-raysà however, this will eventually progress to static changes
• Scaphoid will flex as injury progresses leading to an increased SL and radioscaphoid angle (cortical ring sign), collapsed carpal height due to capitate subsidence, and extended lunate.
• Criteria for radiographic diagnosis of SL injury include: Increased scapholunate angle >60 SL gap >3mm 

• Ancillary imaging: includes MRI and MRI arthrogram
• Arthroscopy is gold standard for diagnosis (anatomic and functional evaluation) and includes a grading system based on the appearance of the SL ligament and the ability to pass an arthroscope through the scapholunate interval. (Geissler Grade)

• The progression of scapholunate instability can occur over time or acutely with trauma. Progression typically as follows: occult injuriesdynamic injuriesscapholunate dissociation (static deformity)DISI deformity (in which the lunate is extended and the scaphoid is flexed) and finally the development of SLAC wrist or scapholunate advanced collapse

• The stages of SLAC wrist are:

a. Stage 1: arthritis at the radial styloid
b. Stage 2: arthritis of the entire scaphoid fossa of the distal radius
c. Stage 3: arthritis of the capitolunate articulation.

• Treatment of these injuries is very complex and depends on the stage of scapholunate injury as well as surgeon preference (dynamic or static injury vs SLAC)
• In general: 
• Acute: Dorsal ligament repair through bone tunnels or suture anchors with supplemental K wire fixation of SL and SC joints. Protective motion 2-3 months
• Partial tears: debridement (arthroscopic) pinning and immobilization 
• Chronic injuries (those that are still reducible) : salvage procedures- dorsal capsulodesis (dynamic instability), tendoesis (Brunelli recosntruction with FCR), bone ligament bone reconstruction, or arthrodesis (scaphotrapezial/scaphocapitiate) 
• Arthritis: radial styloidectomy (Stage 1 SLAC), proximal row carpectomy, scaphoid excision and 4 corner fusion, complete arthrodesis or arthroplasty for later stages
• Rehab after SL repair- dart-thrower’s motion (radial deviation in extension to ulnar deviation in flexion) minimizes the motion between the scaphoid and lunate bones

• Lunate dislocation, or type IV perilunate dislocation, represents complete disruption of the ligamentous stabilizers of the lunate except the short radiolunate ligament
• Spilled teacup sign on lateral x-ray
• If failed closed reduction and persistent median nerve symptoms, will need urgent carpal tunnel release

Degenerative Arthritis:

• Osteoarthritis of CMCJ presents with pain with gripping and pinching
• Anatomy
• 5 major stabilizing ligaments of the CMCJ:
• Anterior (volar) oblique
• Ulnar collateral
• Intermetacarpal
• Dorsoradial resists dorsal dislocations
• Posterior (dorsal) oblique  resists dorsal dislocations
• CMCJ is a BICONCAVE SADDLE joint
• XR: Eaton stress view used to visualize thumb basal joint subluxation
• Stage 1: joint synovitis and preservation of articular surface
• Ligament recon: volar beak reconstruction with FCR  volar beak laxity is the first pathologic process of arthritis of the basal thumb joint
• Metacarpal osteotomy: to adjust adduction contracture
• Arthroscopic debridement and thermal capsulorraphy; no long term data
• Stages 2-4:
• Ablation of involved articular surface
• Arthrodesis- option for a laborer:
• Incision between APL and EPB to approach capsule
• Total trapeziectomy +- LRTI
• Implant arthroplasty
• Partial trapeziectomy with interposition arthroplasty
• Tightrope procedure
• Wrist arthritis
• STT arthritis presents with pain over radial aspect of wrist but negative grind test- treat with STT joint fusion
• 4 corner fusion (capitate+luntate+hamate+triquetrum) if lunoradial joint preserved
• Proximal row carpectomy- need intact capitolunate articulation
• Capitate falls into lunate fossa of radius  recovery of 80% of grip strength and 50-60 degrees ROM
• Total wrist arthroplasty
• Wrist arthrodesis salvage procedure