Summary Phalanx Dislocations are common traumatic injury of the hand involving the proximal interphalangeal joint (PIP) or distal interphalangeal joint (DIP). Diagnosis can be made clinically and are confirmed with orthogonal radiographs. Treatment is closed reduction and splinting unless volar plate entrapment blocks reduction or a concomitant fracture renders the joint unstable. Epidemiology Incidence common injury, especially in athletes Anatomic location PIP joint dislocations login to view 3 more bullets fracture-dislocations DIP joint dislocations fracture-dislocations Etiology Mechanism of injury Generally due to direct blow Fracture dislocations due to avulsion impaction shear Associated conditions swan neck deformity nail bed injuries usually associated with distal phalanx fractures Anatomy Distal Interphalangeal Joint osteology hinge joints stabilized by collateral ligaments login to view 5 more bullets terminal extensor tendon login to view 1 more bullet FDP login to view 1 more bullet volar plate login to view 3 more bullets Proximal Interphalangeal Joint osteology a hinge joint is stabilized by collateral ligaments login to view 5 more bullets central slip login to view 1 more bullet FDS login to view 1 more bullet volar plate login to view 3 more bullets Presentation Physical exam inspection pain and deformity of the affected digit skin puckering may indicate interposition of soft tissues within the joint motion important to assess stability of the joint after reduction passive stability login to view 12 more bullets active stability login to view 2 more bullets neurovascular evaluate sensation in adjacent digits login to view 1 more bullet Imaging Radiographs recommended views AP lateral oblique findings V sign login to view 2 more bullets Diagnosis Clinical and radiographic diagnosis confirmed by history, physical exam, and radiographs PIP Dislocations Introduction dorsal dislocations are more common than volar dislocations dorsal dislocations can lead to a swan neck deformity volar dislocations can lead to a boutonniere deformity Epidemiology incidence most commonly injured joint in the hand Classification dorsal dislocations results from PIPJ hyperextension with longitudinal compression (i.e. ball striking fingertip) leads to tearing of the collateral ligaments and shearing of the volar plate off of the base of middle phalanx commonly seen with small avulsion fracture of the base of the middle phalanx simple login to view 2 more bullets complex login to view 3 more bullets volar dislocations simple login to view 2 more bullets rotatory login to view 3 more bullets lateral dislocations results from rupture of one collateral ligament and at least partial avulsion of volar plate from middle phalanx Treatment nonoperative closed reduction and buddy taping (or splinting) login to view 5 more bullets technique login to view 11 more bullets operative open reduction login to view 10 more bullets Complications PIP flexion contracture (pseudoboutonniere) may develop but usually resolves with therapy more commonly seen in volar dislocations swan neck deformity occurs secondary to a volar plate injury seen in dorsal dislocations extensor lag seen in volar dislocations PIP Fracture-Dislocations Introduction PIPJ fracture-dislocations can be volar or dorsal volar lip fractures are the most common fracture pattern seen with dorsal dislocations highly comminuted fracture may occur, known as "pilon" Pathophysiology mechanism of injury avulsion login to view 2 more bullets impaction shear login to view 1 more bullet Classification Hastings Classification (based on amount of P2 articular surface involvement) Type I < 30% (stable) Type II 30-50% (tenuous) Type III > 50% (unstable) Treatment nonoperative closed reduction and splinting login to view 7 more bullets operative CRPP vs. ORIF login to view 5 more bullets dynamic distraction external fixation login to view 2 more bullets volar plate arthroplasty vs. arthrodesis login to view 2 more bullets hemi-hamate arthroplasty login to view 2 more bullets Technique reduction of the middle phalanx on the condyles of the proximal phalanx is the primary goal adequate volar exposure of the volar plate requires resection of login to view 3 more bullets DIP Dislocations & Fracture-Dislocations Introduction DIPJ dislocations are usually dorsal or lateral volar dislocations are rare often associated with open wounds due to tight soft tissue envelope Classification DIPJ dislocations dorsal volar login to view 1 more bullet lateral DIPJ fracture-dislocations volar login to view 1 more bullet dorsal login to view 1 more bullet Treatment nonoperative closed reduction +/- splinting login to view 9 more bullets operative open reduction +/- FDP repair login to view 8 more bullets volar plate arthroplasty login to view 2 more bullets arthrodesis login to view 2 more bullets amputation login to view 2 more bullets Complications DIPJ stiffness mallet finger deformity seen with volar dislocations