|Considerations||Index Finger (Second) Metacarpal||Middle Finger (Third) Metacarpal|
|Approach||Consider soft-tissue injury||2 incisions||3 incisions, transposition of EPL|
|Reduction||Ligamentotaxis indirect reduction possible for some but not all fractures13||Indirect vs. open reduction||Indirect vs. open reduction. Additional standard incision over 4th extensor compartment may facilitate reduction of lunate facet or volar lip9,18|
|Biomechanics||Biomechanical stability must support loading during fracture-healing||Superior biomechanical stability to extension and flexion forces compared with external fixation16||No studies specifically addressing biomechanics of plating to the 3rd metacarpal|
|Tendon||Wrist joint immobilization limits motion of wrist extensor tendons but not digital extensor excursion||No tendinous entrapment in cadaveric studies33. Average length of ECRB tendon contact to plate, 6 cm34. Average ECRL tendon contact to plate, 6.5 cm34. Average index EDC and EIP contact, 0.8 cm. No middle EDC contact||EPL and either APL or APB consistently entrapped in cadaveric model33†. No ECRL or ECRB contact34. Average length of index finger EDC and EIP contact to plate, 5.1 cm34. Average middle finger EDC contact, 10.4 cm34. EIP and EPL tendon entrapment possible with 2-incision technique34|
|Nerve||Iatrogenic nerve injury can result in poor outcomes||Branches of the RSN at risk34||No branches of RSN observed crossing over the middle finger metacarpal in cadaveric studies33,34. PIN lies below footprint of plate34|
|Retinaculum||Extensor retinaculum irritation and rupture is of concern||No entrapment or injury noted in cadaveric models33,34||Risk of splitting or entrapping extensor retinaculum33†|
↵* EPL = extensor pollicis longus, ECRB = extensor carpi radialis brevis, ECRL = extensor carpi radialis longus, EDC = extensor digitorum communis, EIP = extensor indicis proprius, APL = abductor pollicis longus, APB = abductor pollicis brevis, RSN = radial sensory nerve, PIN = posterior interosseous nerve.
↵† Cadaveric model did not incorporate 3-incision technique as is used clinically.