Metacarpophalangeal Joint Dislocation
Other Names
- MCP Joint Dislocation
- MCP Dislocation
- Dorsal MCP dislocation
- Volar MCP dislocation
- Kaplan's lesion
Background
- This page describes dislocations to the Metacarpophalangeal Joint
History
- Kaplan was the first to describe the complex dislocation in which the volar plate is interposed[1]
Epidemiology
- Needs to be updated
Introduction
General
- Typically a fall on outstretched hand with hyperextension mechanism
- Dorsal dislocation more common than volar dislocation
Dorsal Dislocation
- Typically fall on outstretched hand, subsequent hyperextension of the joint
- Dorsal dislocation more common than volar dislocation
- Index finger most commonly affected, followed by the thumb[4]
- Acute hyperextension
- Volar plate is avulsed from its attachment to the metacarpal neck
- Simple Dislocation
- Volar plate is not interposed within the joint
- Base of proximal phalanx remains intact with metacarpal head
- Collateral ligaments may/ may not be torn
- Complex Dislocation
- Volar plate becomes interposed dorsally in the joint
- This means you can not reduce the dislocation closed
- This can be termed Kaplan's lesion[1]
- Index finger: displacement of lumbrical radially, flexor tendons ulnarly
- Pinky finger: ulnar displacement of abductor digiti minimi, radial displacement of flexor tendons
- Metacarpal head entraped by natatory ligament, superficial transverse metacarpal ligament
- These structures form a tight noose around the metacarpal neck
Volar Dislocation
- Far less common than dorsal dislocation
- Can occur from hyperflexion or hyperextension
- Cadaver study: mechanism is hypeflexion with proximal translation force applied to proximal phalanx[5]
- Complex Dislocation
- Can not be reduced with closed reduction maneuvers
- Implicated interposed structures: dorsal capsule, volar plate or collateral ligament[6]
Anatomy of the Metacarpophalangeal Joint
- Articulation is proximal phalanx and head of the metacarpals
- Joint capsule is stabilize by ligamentous complex
- Dorsal capsule most vulnerable to dislocation
- Thumb MCPJ structure similar to other MCP joints, however more hinge-like
Associated Conditions
- Metacarpal Fractures
- Phalanx Fractures (Hand)
- Either fracture is seen in about 50% of MCP joint dislocation[7]
Risk Factors
- Unknown
Differential Diagnosis
Differential Diagnosis Finger And Hand Pain
- Fractures
- Dislocations
- Tendinopathies
- Extensor Tendon Injuries of the Hand
- Central Slip Extensor Tendon Injury
- Flexor Tendon Injuries of the Hand
- Boutonniere Deformity
- Swan Neck Deformity
- Jersey Finger
- Mallet Finger
- Trigger Finger
- De Quervains Tenosynovitis
- Volar Plate Avulsion Injury
- Sagittal Band Injury
- Mannerfelt Lesion (FPL Rupture)
- Ligament Injuries
- Neuropathies
- Arthropathies
- Nail Bed Injuries
- Pediatric Considerations
- Other
Clinical Features
History
- Patients can describe some type of trauma, typically fall on outstretched hand
- Volar dislocations are more likely hyperflexion mechanism
Physical Exam: Physical Examination Hand
- Inspection: Deformity generally obvious
- Dorsal: hyperextended proximal phalanx with flexion at PIPJ
- Reducible: proximal phalanx perched in hyperextension on the metacarpal head, PIPJ in flexion
- Irreducible: proximal phalanx lies dorsal to the metacarpal shaft in a bayonet position
- Neither active nor passive range of motion is possible
- Volar: loss of extension, dorsal skin depression
- Flexion may be intact with extensor lag present
- Dorsally a depression can be palpated at the base of the proximal phalanx
- Kaplan's sign: dimpling of the skin in the palmar crease suggest dorsal dislocation of MCPJ
- Suggests increased likelihood of an irreducible dislocation
Evaluation
- Standard Radiographs Hand
- Sufficient to make the diagnosis
- Typical findings
- Findings seen in complex cases
- Widened joint space indicating interposed volar plate
- In thumb, sesamoid can be entrapped in the joint
Classification
Anatomic
- Volar
- Dorsal (more common)
Complexity
- Simple: no interposition of Volar Plate, sesamoids
- Complex: interposition of volar plate and/or sesamoids
- Metacarpal head becomes entrapped by displaced ligaments
- Kaplan's lesion: rare, metacarpal head buttonholes volarly into palm
- Most common in index finger
Management
Acute Management
- Consider Digital Block and ensure adequate analgesia
- Reduction: May reduce with just traction
- Simple Dorsal dislocation:
- Relax flexor tendons by flexing wrist, proximal interphalangeal joint
- Apply dorsal-to-volar pressure to the base of the proximal phalanx
- Then hyperextend the joint and apply dorsal pressure over the proximal phalanx in distal and volar direction
- More likely to be successful in the thumb than other digits[10]
- Simple Volar dislocation:
- Less common, harder to reduce with closed reduction
- Hyperflex the joint and then apply traction and extend finger
- Apply gentle pressure to the volar surface of the proximal phalanx
- Guide proximal phalanx into place
- Splint with MCP joint in flexion
- Dorsal blocking splint
- 1st: thumb spica splint
- 2nd/3rd: radial gutter splint
- 4th/5th: ulnar gutter splint
Nonoperative
- Closed reduction for simple dislocations
- Physical Therapy
- Early range of motion is encouraged
- Dorsal blocking splint to prevent extension beyond neutral
Operative
- Indications
- Complex or irreducible dislocations
- Technique
- Open reduction for complex dislocations
Rehab and Return to Play
Rehabilitation
- Needs to be updated
Return to Play/Work
- Needs to be updated
Prognosis and Complications
Prognosis
- Delay in treatment is associated with worse outcomes[11]
Complications
- Mostly related to inadequate diagnosis and treatment
- Finger osteoarthritis
- Can occur as a result multiple attempts at closed reduction, traumatic open or prolonged dislocation
- Avascular necrosis of metacarpal head
- Joint stiffness
- Most common complication related to this injury
- Thought to occur from soft tissue trauma and/or prolonged immobilization
- Surgical complications
- Damage to the neurovascular bundle
See Also
Internal
External
- Sports Med Review Hand Pain: https://www.sportsmedreview.com/by-joint/hand/
References
- ↑ 1.0 1.1 Kaplan EB: Dorsal dislocation of the metacarpophalangeal joint of the index finger. J Bone Joint Surg Am 1957;39: 1081-1086.
- ↑ Image courtesy of teachmenanatomy.info, "metacarpophalangeal"
- ↑ 3.0 3.1 Dinh, Paul, et al. "Metacarpophalangeal joint dislocation." JAAOS-Journal of the American Academy of Orthopaedic Surgeons 17.5 (2009): 318-324.
- ↑ MALERICH, MATTHEW M., RICHARD G. EATON, and JOSEPH UPTON. "Complete dislocation of a little finger metacarpal phalangeal joint treated by closed technique." Journal of Trauma and Acute Care Surgery 20.5 (1980): 424-425.
- ↑ MB, WOOD. "Chronic complex volar dislocation of the metacarpophalanreal joint." J Hand Surg 6 (1981): 73-76.
- ↑ Lam, W. L., A. M. Fitzgerald, and G. Hooper. "Volar metacarpophalangeal joint dislocation." Emergency Medicine Journal 17.3 (2000): 226-228.
- ↑ 7.0 7.1 Kiefhaber TR: Intra-articular fractures in joint injuries, in Hand Surgery Update. Rosemont, IL: American Society for Surgery of the Hand, 1994, pp 17-27.
- ↑ Elghoul, Naoufal, et al. "Complex metacarpophalangeal joint dislocation of the litter finger: A sesamoid bone seen within joint. What does it mean?." Trauma Case Reports 23 (2019): 100225.
- ↑ Tavin, Ellis, and R. Christie Wray Jr. "Complex dislocation of the index metacarpophalangeal joint with entrapment of a sesamoid." Annals of plastic surgery 40.1 (1998): 59-61.
- ↑ Takami, H., S. Takahashi, and M. Ando. "Complete dorsal dislocation of the metacarpophalangeal joint of the thumb." Archives of orthopaedic and trauma surgery 118 (1998): 21-24.
- ↑ Murphy, Allen F., and Herbert H. Stark. "Closed dislocation of the metacarpophalangeal joint of the index finger." JBJS 49.8 (1967): 1579-1586.
Created by:
John Kiel on 18 June 2019 23:09:24
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Last edited:
25 June 2024 16:08:12
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