• General principles: Spiral fractures are a result of torsional forces; axial loading compression cause oblique fractures; tension/three point bending cause transverse fractures

Distal phalanx fractures:

• Open fractures do not require antibiotics 
• Tuft fracture: splint 14 days
• Shaft fracture: splint vs operative fixation (closed or open) depending on stability
• Base: DIP fractures involving the joint surface can cause persistent subluxation if they involve over 50% of the joint surface 
• Treatment: surgical treatment recommended if >1/3 articular surface is involved
• Conservative treatment with DIP in extension 6-8 weeks and PIP free
• Complication: for every 1mm length in extensor tendon –> extensor lag 25 degrees; skin complications if closed
• Fixation is with extension block pinning
• Seymour Fractures: physeal fractures (salter harris/ fracture of growth plate) of distal phalanx with interposition of proximal nail matrix –> requires open reduction –> remove nail –> remove interposed germinal matrix –> splint (or K wires)
• Always an open fracture
• DIPJ
• Mallet finger: sudden forced flexion causes disruption of the terminal extensor tendon distal to the DIPJ – fingertip rests at ~45° of flexion and DIPJ cannot be actively extended. 
• Jersey finger: avulsion of FDP from DP, most commonly of ring finger, type 1 retracts to palm (repair in 2 weeks), II retracts to PIP to A3 pulley (repair in 3 months), type III retracts to A4 pulley can be repaired at any time even after 3 months — ORIF–with screws or wiring

Middle phalanx fractures

• Head: London classification –> for classification of fractures extending into DIP joint

• I: (non-displaced unicondylar) and can be treated by orthosis x 3 weeks –> buddy taping 2-3 weeks
• II: unstable unicondylar, K wire or screw fixation
• III: unstable bicondylar or comminuted – reconstruction difficult.
• Shaft fractures: stable fractures after reduction may be treated closed (3 weeks orthosis and then buddy taping 2-3 weeks)
• Acceptable alignment includes no clinical malrotation and no angulation >10
• Oblique fractures need K wire or screw fixation

• PIPJ
• volar dislocations (distal is volar) are usually irreducible due to partial rupture of the volar plate.  the condyle can become entrapped between the central slip and lateral band fibers (aka buttonhole). central slip injury common –> lack of recognition can lead to boutinniere deformity
• Reduce via gentle traction and MCP/PIP flexion
• repair includes central slip and lateral band repair (divide transverse retinacular ligaments), may need to divide the A3 pulley to move the condyle back beneath flexor tendons
• Buddy taping used for PIP joint collateral ligament injury
• Fracture dislocation – if <25% articular surface, splint; >25% needs op stabilization
• Dorsal Dislocation of PIP: (distal is dorsal) more stable in flexion and unstable in extension. FDP and volar plate can block reduction
• V sign on lateral XR results from dorsal subluxation of the middle phalanx 
• Fracture-dislocation: If it can be reduced in <30 degrees of flexion or if there is <20% articular involvement of middle phalanx base, it is considered stable. >50% articular involvement is unstable.
• Treatment options: 

• Stable –> Extension block splinting/pinning
• Unstable/comminuted –> External fixation and dynamic traction
• Unstable with large pieces –> ORIF need dorsal lip to be intact
• For posttraumatic degeneration of PIPJ in ulnar digits, arthrodesis is the treatment. For destroyed radial digits, arthroplasty is recommended.
• Another option for fractures less than 50-60% of the articular base of the middle phalanx –> Volar Plate Arthroplasty
• Fractures >50% articular surface –> Hemi-hamate arthroplasty
• Most common complication is arthrosis

Proximal Phalanx Fractures

• Anatomy: Angulation from fractures is always volar- proximal fragment is flexed by interosseous attachments while distal fragment is extended by the extensor central slip resulting in PIP extension lag
• nondisplaced closed fractures –> buddy taping and early ROM. need to have at least 50% apposition, no malrotation in full flexion, less than 15 degrees sagittal or frontal plane angulation
• Reduction maneuver- digital traction + flexion of MCP
• Unstable or nonreducible –> operative fixation

 
MCPJ

• Anatomy
• UCL proper originates from dorsal-ulnar aspect of MP head and inserts into volar part of proximal phalanx. Accessory UCL is contiugous but just volar to the proper, and inserts on the volar plate of MCP
• RCL proper originates dorsoradial and attaches on the lateral tubercle of the proximal phalanx
• MCP dorsal dislocation: again, fractures are described based on the distal segment’s position relative to the joint so the finger is dorsal and the MC head is volar. May also have flexion of PIP/DIP. index finger most commonly involved
• Mechanism is usually forced hyperextension
• Attempt closed reduction. if it is nonreducible, it is likely to have injury/displacement of volar plate, FDP, lumbricals
• Flexors generally displace ulnar to metacarpal head except in the small finger where it goes radial (ADM and FDM still go ulnar), and radial digital nerve is superficial (risk with volar open approach)
• Method: closed reduction is attempted with wrist flexion (relax flexors) gentle extension, and push down on dorsal proximal phalanx. avoid longitudinal traction as this can essentially create a noose with the lumbrical (radial) and flexor tendon (ulnar) preventing reduction. 
• Open reduction: division of volar plate is typically needed because it may be stuck in the dislocated joint

• MCP dorsal dislocation of thumb: typically can be closed reduced –> gentle hypertextension of MCP with direct pressure on dorsal base of the proximal phalanx 
• FPL and thenar musculature can also trap the metacarpal head like a noose –> wrist flexion can help alleviate
• MCP volar dislocations: rare and closed reduction is generally successful. 
• Ligamentous injury
• RCL injuries occur with acute adduction
• UCL incjuries occur with acute abduction (“skiiers thumb acute or gamekeepers thumb chronic”)
• Stener lesion (thumb): UCL avulses and retracts proximally, and the adductor aponeurosis interposes and precludes primary healing
• Dx: 10-15 degrees in laxity in excess of contralateral side indicates complete tear, US, MRI is most sensitive/specific
• Tx – strain/laxity can be treated with immobilization, avulsions or tears usually need reconstruction vs repair

Metacarpals:

• joint type: hinge joint for thumb, condyloid for index/small fingers

• Cam effect: construct that translates rotary motion into linear motion (flexion of MP puts stretch on collateral ligaments)
• Dorsal wounds over metacarpal fractures almost always open to the fracture; volar wounds may not communicate
• Imaging: 
• Standard PA, lateral, oblique
• Brewerton for metacarpal head
• 30-45 oblique for cmc
• Roberts view for thumb CMC

Metacarpal Head Fractures:

• No degree of articular displacement is acceptable
• ORIF via dorsal incision with central split of extensor hood or release and repair of sagittal band
• If severely comminuted consider ex-fix or MCP joint replacement (arthrodesis or arthroplasty last options)

Metacarpal Neck Fractures

• Metacarpal neck fractures: occurs when axial load applied to clenched fist, apex dorsal angulation because intrinsic muscles lie volar
• Acceptable angulation 
• Index: 10°-15°
• Middle: 10°-15°
• Ring: 20°-40°
• Small: 20°-60°
• Deformity from fracture: loss of appearance of the knuckle, bump in the palm (pseudoclawing; MCP hyperextension and PIP flexion)
• Reduction: Jahss maneuver: 90 MCP flexion –> dorsal pressure through proximal phalanx while stabilizing metacarpal shaft
• Treatment: 
• Cast immobilization- MCP 70-90 to stretch the collaterals (PIP free); should cast for 3-4 weeks
• Operative Treatment: (any malrotation, unacceptable angulation)
• CRPP with MCP flexed to prevent collateral contractures; leave PIP free to encourage PIP motion

Metacarpal Shaft Fractures: 

• Acceptable Angulation: Index <10, middle <10, ring 20, small 30. No malrotation acceptable
• Treatment (same as neck treatments) casting or ORIF. Can include plate or IMN. Non-compressing for oblique, compression for transverse
• Reduce (apex dorsal so volarly directed pressure with prox phalanx flexed, traction, monitor your angulation)
• Interossei originate on the metacarpal shaft so will be attached to the fracture fragment

Metacarpal Base Fractures:

• Extra-articular fractures – treat similar to metacarpal fractures
• Intra-articular fractures need anatomic reduction –> consider CT scans –> likely ORIF
• Additional X ray views include AP view with forearm pronated 30 degrees (can show 5th CMC), lateral with 30 degrees (again for 5th CMC)
• First metacarpal
• Extra-Articular Metacarpal Base Fracture 
• Presents in apex dorsal angulation with adduction, flexion, and supination of distal fragment
• Acceptable angulation 20-30 (angulation causes decreased thumb web space and MCP hyperextension

• Reduction: TAPE longitudinal traction/abduction/pronation/extension
• Treatment: closed reduction with K wires through CMC

• Intraarticular Fracture Dislocation (Bennett Fracture)–> an intraarticular base fracture of the first metacarpal with 2 components. volar fragment is small and attached via AOL and trapezium and dorsal fragment is attached to metacarpal shaft –> the dorsal fragment tends to migrate proximally, dorsally, and radially (via the forces of APL AdP, EPL EPB) (creates apex dorsal angulation)
• Rolando fractures: comminuted intraarticular base fracture of first metacarpal. Can appear as a T or Y type (named for appearance on XR)
• Fifth metacarpal
• Reverse Bennett: fifth metacarpal base fracture with dorsal subluxation, deforming forces include FCU/ECU, ADM. reduce by traction, pronation, and dorsal/radial pressure at base
• Treatment: CRPP or ORIF

CMC Joints

• Thumb CMC is a saddle joint; 16 ligaments supporting the joint (anterior oblique and dorsal radial most important); dorsal capsule contiguous with extensor/abductor mechanism
• Volar ligaments – AOL is the primary stabilizer
• Dorsal ligament (posterior oblique, dorsoradial, and dorsal central) are the strongest ligaments in the joint and crucial for dorsal stability
• Eval: XR with dynamic stress view (accentuates radioulnar laxity), opposing thumbnails (accentuates dorsovolar laxity), roberts view (official view of the CMC). US can be used to view ligaments

Miscellaneous: 

• Salter Harris is the classification of growth plate fractures. (seymour is the DIP version of this)
• Type 1 – straight across the growth center
• Type 2- oblique fracture above the growth center
• Type 3 – fracture of the bone. Below the growht center
• Type 4 – through – fracture through the bones above and below the growht centers
• Type 5 – crush, erases the growth center

• Wrist fractures:
• Supracondylar fracture: occurs most commonly in patients 5-7 years of age, fall on outstretched hand –> risk of ischemia 

• Immediate closed reductoin needed (gentle traction and elbow flexion) –> followed by operative closed reduction if unsuccessful or ischemia persists
• Most common wrist fractures: distal radius, scaphoid, triquetrum, lunate
• Types of bone grafting: 
• Osteoconduction: refers to replacement of graft material through process of creep substitution (cortical grafts, calcium hydroxyapetite)
• Osteoinduction: stimulation of bone forming cells from surrounding host tissues (cancellous grafts, demineralized bone matrix, and cortical bone)
• Osteogenesis: autografts like cancellous, vascularized bone
• Noncritical bone defects <6cm can undergo autologous bone grafting (corticocancellous from iliac crest)
• Distraction osteogenesis may work if the bone has adequate stock on either side of fracture