Metacarpophalangeal Joint Dislocation Workup
- Author: Matthew Gammons, MD; Chief Editor: Craig C Young, MD more...
Laboratory Studies
Laboratory studies generally are not indicated in the diagnosis of metacarpophalangeal (MCP) joint injuries.
Imaging Studies
Static x-ray films (see the images below)
Metacarpophalangeal joint dislocation of the small finger. Posteroanterior radiograph demonstrates loss of joint space.
Metacarpophalangeal joint dislocation of the small finger. Oblique radiograph best demonstrates dorsal dislocation of proximal phalanx.
Metacarpophalangeal joint dislocation of the small finger. Dorsally dislocated proximal phalanx is obscured by other digits. Note that the small finger metacarpal sits palmar to the other metacarpals. Obtain anteroposterior, lateral, and oblique radiographic views. Brewerton views (MCP joint flexed 65°, with the dorsum of the proximal phalanx flat against the radiograph cassette and the beam angled 15° ulnar to radial) profile the collateral recesses and are helpful for collateral ligament avulsion fractures.
Obtain a lateral view of the injured digit, not a lateral view of the hand.
Prereduction and postreduction x-ray films are necessary to demonstrate associated fractures and joint congruency.
An incongruent joint can be caused by interposed soft-tissue or gross instability.
Joint subluxation after reduction is associated with interposed soft-tissue or severe capsular injury.
Procedures
Closed reduction of hyperextension – Simple dorsal dislocation
Use local anesthetic or intravenous sedation.
Apply pressure over the dorsal proximal phalanx, gently pushing in a palmar and distal direction, while simultaneously placing the metacarpophalangeal joint dislocation (MCP) joint into flexion.
empty para to satisfy content modelFlexing the wrist initially may aid reduction by relaxing the flexor tendons.
Never use longitudinal traction because this may entrap the metacarpal head in already tightened soft tissues or pull the volar plate into the joint, converting a simple dislocation into a complex dislocation.
Postreduction x-ray films confirm satisfactory reduction.
Maintain reduction in dorsal splint with the MCP joint flexed 30º.
Closed reduction of the thumb MCP joint – Dorsal dislocation
Closed reduction may be performed with local anesthesia, intravenous sedation, or regional block.
Apply a distal and volarly directed force to the dorsal base of the proximal phalanx, followed by placement of the MCP joint in mid flexion.
Postreduction x-ray films confirm satisfactory reduction.
Closed reduction of the thumb MCP joint – Volar dislocation
Most dorsal dislocations require open reduction owing to the presence of interposed structures: dorsal capsule, volar plate, extensor pollicis longus (EPL), extensor pollicis brevis (EPB).
Consider attempts at closed reduction if sesamoids are not interposed on radiographs or any of the following physical examination findings are present[10] :
- No palpable EPL on initial examination
- Radial or ulnar displacement of the EPL or EPB
- Paradoxical MCP joint flexion and interphalangeal joint extension with attempted MCP extension
Use local anesthesia, intravenous sedation, or regional block.
Apply a dorsally directed force to the volar base of the proximal phalanx with hyperflexion at the MCP joint, followed by placement of the MCP joint in extension.
Postreduction x-ray films confirm satisfactory reduction.
Closed reduction of the locked thumb MCP joint
Occasionally, instillation of local anesthetic directly into the joint distends the capsule enough to allow gentle correction of the hyperextension deformity.
This should then be immobilized in approximately 20° of MCP joint flexion.
Glickel SZ, Barron OA, Eaton RG. Dislocations and ligament injuries in the digits. In: Green DP, Hotchkiss RN, Pederson WC, eds. Green's Operative Hand Surgery. 4th ed. New York, NY: Churchill Livingstone; 1999:772-807.
Neviaser RJ. Dislocations and ligamentous injuries of the digits. In: Chapman MW, ed. Operative Orthopaedics. 2nd ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 1993:1237-50.
Lourie GM, Gaston RG, Freeland AE. Collateral ligament injuries of the metacarpophalangeal joints of the fingers. Hand Clin. Aug 2006;22(3):357-64, viii. [Medline].
Zemel NP. Metacarpophalangeal joint injuries in fingers. Hand Clin. Nov 1992;8(4):745-54. [Medline].
Melone CP Jr, Beldner S, Basuk RS. Thumb collateral ligament injuries. An anatomic basis for treatment. Hand Clin. Aug 2000;16(3):345-57. [Medline].
Posner MA, Retaillaud JL. Metacarpophalangeal joint injuries of the thumb. Hand Clin. Nov 1992;8(4):713-32. [Medline].
Kaplan EB. Dorsal dislocation of the metacarpophalangeal joint of the index finger. J Bone Joint Surg Am. Oct 1957;39-A(5):1081-6. [Medline]. [Full Text].
Tabib W, Sayegh S. Simultaneous dislocation of the metacarpophalangeal and interphalangeal joints of the thumb. Scand J Plast Reconstr Surg Hand Surg. 2002;36(6):376-8. [Medline].
Inoue G, Miura T. Locked metacarpo-phalangeal joint of the thumb. J Hand Surg [Br]. Nov 1988;13(4):469-73. [Medline].
Beck JD, Klena JC. Closed reduction and treatment of 2 volar thumb metacarpophalangeal dislocations: report of 2 cases. J Hand Surg Am. Apr 2011;36(4):665-9. [Medline].
Ip KC, Wong LY, Yu SJ. Dorsal dislocation of the metacarpophalangeal joint of the thumb: a case report. J Orthop Surg (Hong Kong). Apr 2008;16(1):124-6. [Medline]. [Full Text].
Dinh P, Franklin A, Hutchinson B, Schnall SB, Fassola I. Metacarpophalangeal joint dislocation. J Am Acad Orthop Surg. May 2009;17(5):318-24. [Medline].
Maheshwari R, Sharma H, Duncan RD. Metacarpophalangeal joint dislocation of the thumb in children. J Bone Joint Surg Br. Feb 2007;89(2):227-9. [Medline].
Marcotte AL, Trzeciak MA. Nonoperative treatment for a double dislocation of the thumb metacarpal: a case report. Arch Orthop Trauma Surg. Mar 2008;128(3):281-4. [Medline].
Orozco JR, Rayan GM. Complex dorsal metacarpophalangeal joint dislocation caused by interosseous tendon entrapment: case report. J Hand Surg [Am]. Apr 2008;33(4):555-7. [Medline].
Peterson JJ, Bancroft LW. Injuries of the fingers and thumb in the athlete. Clin Sports Med. Jul 2006;25(3):527-42, vii-viii. [Medline].

