A volar plate is a strong fibrocartilaginous tissue located on the palm side of finger joints, primarily stabilizing the proximal interphalangeal (PIP) joint, which is the middle knuckle of the finger. This plate helps maintain the integrity and proper movement of the finger.
Volar Plate Anatomy and Function
The volar plate is a thick ligament made of fibrocartilage. It is situated on the palmar side of the metacarpophalangeal (MCP) and interphalangeal (IP) joints, reinforcing the joint capsules. Injuries most commonly affect the PIP joint, located between the first and second phalanges of each finger. The plate forms the floor of this joint, separating the joint space from the flexor tendon sheath.
This structure is firmly attached to the bone at the distal end of the joint, at the base of the middle phalanx. Proximally, it has an attachment to the proximal phalanx via two lateral bands known as checkrein ligaments. The central portion of the plate remains unattached proximally, which allows for flexibility. This design enables the plate to glide proximally during finger flexion, preventing restriction of movement and protecting the long flexor tendons from being pinched within the joint.
The primary function of the volar plate is to prevent hyperextension, the backward bending of the finger beyond its normal range. It acts as a “seatbelt” for the joint, tightening when the finger straightens to provide stability. Alongside the collateral ligaments, located on either side of the joint, the volar plate ensures the joint remains stable, preventing displacement and facilitating a stable yet flexible range of motion. This combined stability contributes to the hand’s fine motor skills and gripping capabilities.
Understanding Volar Plate Injuries
A volar plate injury occurs when this structure is overstretched or torn, due to forced hyperextension of a finger joint. These injuries are common in sports, particularly those involving balls, where a direct impact can bend the finger backward excessively. Falls onto an outstretched hand can also cause such injuries, as the fingers absorb the force.
Injuries to the volar plate can range in severity. A mild injury might involve a sprain, an overstretching of the ligament without significant tearing. More severe cases can result in partial tears, where some fibers are ruptured, or complete ruptures, indicating a full tear of the plate. Sometimes, the force of the injury is strong enough to pull a small piece of bone away from its attachment point, known as an avulsion fracture.
Symptoms of a volar plate injury appear immediately after the incident. Individuals often experience pain and swelling around the affected joint, with tenderness on the palm side. Bruising may also become apparent around the joint and can sometimes spread. The injured finger may become stiff, making it difficult to bend or straighten, and in severe cases, the joint might appear unstable or even dislocated.
Diagnosing and Treating Volar Plate Injuries
Diagnosing a volar plate injury begins with a patient history, including a description of how the injury occurred, such as a hyperextension event or direct impact. A medical professional will then perform a physical examination, assessing for swelling, tenderness, and any visible deformity of the affected finger joint. They may also conduct stress tests to evaluate the joint’s stability and the extent of the volar plate’s integrity.
Imaging tests are used to confirm the diagnosis and rule out other issues. X-rays are commonly taken to check for fractures, including avulsion fractures, and to assess for joint dislocations. If soft tissue damage needs further evaluation, an MRI scan may be recommended.
Treatment for volar plate injuries varies based on severity, though most can be managed with conservative methods. This includes rest, applying ice to reduce swelling, compression, and elevation of the hand. Splinting is used to immobilize the finger and prevent further hyperextension for two to four weeks, allowing the ligament to heal. Physical therapy, including exercises to restore strength and range of motion, is an important part of recovery. For more complex cases, such as complete ruptures, significant instability, or large avulsion fractures, surgical intervention may be necessary to repair the ligament or fix bone fragments.