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Volar Plate Stability

Exams and Signs

Historical Overview

  • In 1939, Kaplan first discussed the pure extension injury at the proximal interphalangeal (PIP) joint.1 Volar plate instability may stem from an injury at the PIP joint. In some cases, this injury tears the attachment of the volar plate or results in a volar plate avulsion fracture from the base of the middle phalanx.

Description

  • The volar plate is a capsular ligament that is usually injured at the PIP joint. It may also involve the carpometacarpal (CMC), metacarpophalangeal (MP) and distal interphalangeal (DIP) joints.
  • An unstable PIP joint fracture includes >40% of the joint surface.
  • The volar plate becomes the main stabilizer to lateral deviation when the collateral ligaments are torn.2

Pathophysiology

  • Volar plate stability can be affected by PIP joint injuries or dislocations. These injuries, which often occur in athletic activities, usually damage the volar plate at its attachment to the middle phalanx. If PIP joint injuries are insufficiently treated, this may result in joint stiffness, persistent subluxation, and degenerative changes.3
  • Volar plate instability may occur in conjunction with collateral ligament injuries.
    • As in other fractures, children demonstrate more rapid and effective healing than do adults with PIP joint injuries involving the volar plate.4

Instructions

  1. Record the patient’s history, including any sports-related injuries. Ask the patient to rate how much pain s/he usually experiences in the affected finger on a scale from 1 to 10.
  2. Palpate the volar plate area for tenderness and edema.4
  3. Measure the stability of the PIP joint by comparing the injured joint to the uninjured joint in the contralateral hand. For instance, the right, uninjured, ring finger PIP joint may extend 5° when the volar plate is stressed, while the injured, left, ring finger PIP joint may be tender and hyperextend 60°. This hyperextension verifies a left ring finger volar plate injury.2
  4. In cases of PIP dislocation, examine the finger under digital or wrist block anesthesia, to relieve pain.2

Variations

  • If there is a fracture, determine how much of the PIP joint surface is involved to decide whether operative treatment is required. Type III injuries, with disruption of >40% of the joint surface, indicate a need for surgery.

Related Signs and Tests

  • Plain radiographs with a true lateral X-ray

Diagnostic Performance Characteristics

  • If the volar plate injury occurs with a fracture, and the examination shows excessive hyperextension with tenderness, take true lateral radiographs. This will improve the reliability of a diagnosis of volar plate instability.

Additional Information

Definition of Positive Result
  • A positive result occurs when the exam reveals tenderness at the base of the joint in the area of the volar plate. The volar plate usually shows excessive hyperextension and substantial tenderness.
Definition of Negative Result
  • A negative result occurs when there is a PIP joint exam with no tenderness and no hyperextension exceeding the uninjured opposite joint.
Comments and Pearls
  • To achieve articular congruity and stabilization of the PIP joint, open reduction with internal fixation (ORIF) may be useful, if the fracture fragment is large enough and not comminuted. This method should allow early protected ROM.3
  • Other options to stabilize the PIP joint include volar plate arthroplasty and hemi-hamate graft procedure. Volar plate arthroplasty, a technically challenging procedure, can be used if there is extensive comminution of the fracture fragments.5 A hemi-hamate procedure involves replacing the base of the middle phalanx articular surface.6
  • Another alternative for unstable PIP joint fracture-dislocations is extension-block pinning. This is a simple, safe, and reproducible technique.7
Diagnoses Associated with Exams and Signs
References
  1. Bowers WH. The proximal interphalangeal joint volar plate. II: a clinical study of hyperextension injury. J Hand Surg Am 1981;6(1):77-81. PMID: 7204922
  2. Culp R, Jacoby S. Musculoskeletal Examination of the Elbow, Wrist and Hand: Making the Complex Simple. New Jersey: SLACK Incorporated, 2012.
  3. Hamilton SC, Stern PJ, Fassler PR, Kiefhaber TR. Mini-screw fixation for the treatment of proximal interphalangeal joint dorsal fracture-dislocations. J Hand Surg Am 2006;31:1349-54. PMID: 17027798
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