Introduction

Injuries to the finger joints are common and most heal without significant problems. Some injuries are more serious and may develop problems if not treated carefully. One such injury is a sprain of the proximal interphalangeal joint (PIP) of the fingers. The PIP joint is one of the most unforgiving joints in the body when it comes to injury. What at first appears to be a simple sprain of this joint may result in a painful and stiff finger, making it difficult to use the hand for gripping activities. 

 Anatomy

The finger is made up of three joints the metacarpophalangeal joint (knuckle joint), the proximal interphalangeal joint (PIP), and the distal interphalangeal (DIP).

Ligaments also hold the joints together. In the PIP joint, the strongest ligament is the volar plate. This ligament connects the proximal phalanx to the middle phalanx on the palm side of the joint. The ligament tightens as the joint is straightened and keeps the joint from bending too far (hyperextending).

 
There is also a collateral ligament on each side of the PIP joint. The collateral ligaments tighten when the joint is bent sideways and keep the joint stable from side to side.

Causes

A "sprain" is a general term that means a ligament is injured. Doctors usually use this term to mean that the ligament has been stretched and partially torn. If the ligament is stretched too far, it ruptures or tears completely.
 
Injury to the volar plate can occur when the joint is hyperextended. If a complete tear occurs, the ligament usually ruptures or tears from its attachment on the middle phalanx. There may be a small piece of bone broken from the middle phalanx when this occurs. If small, it is usually of no consequence, but if it is large and involves a significant amount of the joint surface, it may require surgery to fix the fragment and restore the joint surface.

Injury to the collateral ligaments can occur when the joint is forced to bend too far sideways until one of the collateral ligaments ruptures.

These ligaments can also be injured if the PIP joint is actually dislocated, moved out of normal position.

Symptoms

Initially, the finger is painful and swollen around the PIP joint. If the joint has completely dislocated, it will appear deformed.
 
Diagnosis

Usually the diagnosis is evident just from the physical examination. X-rays are required to see if there is a fracture since this may change the recommended treatment. X-rays are also useful to see if the joint is aligned properly after an injury.

Treatment

Conservative Treatment

When the ligaments have been sprained or partially torn, treatment may simply consist of a short period of splinting and early exercise. The PIP joint is sensitive  becoming stiff when immobilized for even short periods of time. The earlier the joint begins to move the less likely there will be a problem with stiffness later on. Many sprains can be treated with "buddy taping" to the adjacent finger. This allows the good finger to brace the injured finger while allowing the good finger to bend the injured finger as the hand is used.

When the volar plate has been completely ruptured or when the joint has been dislocated, nonsurgical treatment is still usually suggested. The goal is to keep the joint in a stable position while beginning motion as soon as possible. Since the injury results from hyperextension, a brace to prevent the joint from straightening completely while still allowing the joint to bend accomplishes both of these goals. The brace is usually worn for three to four weeks until the ligament heals enough to stabilize the joint.

Surgery

In severe cases, surgery may be necessary to repair extensive damage to the collateral ligaments or volar plate. Surgery may be necessary to remove the volar plate if it becomes trapped in the joint and prevents the surgeon from placing the joint in correct alignment.

Rehabilitation

If conservative treatment is successful, improvement will probably occur in three to six weeks. By wearing a dorsal blocking splint, the joint continues to bend freely but is kept from straightening completely.

After three to four weeks, the joint should heal enough to remove the splint and begin strengthening exercises. These exercises may be directed by a physical or occupational therapist.

Injuries to the PIP joint remain swollen for long periods of time. Commonly, the joint will be permanently enlarged due to scarring. This may cause problems with getting rings on and off. It is a good idea to wait for about one year before resizing rings since scarring will continue to remodel and reduce the size of the joint. 

If you?ve had surgery, you'll wear a splint or brace for three weeks to give the repair time to heal. Patients may be seen for physical or occupational therapy afterward. You will likely need to attend therapy sessions for two to three months. Full recovery usually takes up to four months.

The first few therapy treatments will focus on controlling the pain and swelling from surgery followed by gentle range-of-motion exercise. Strengthening exercises are used to give added stability around the finger joint. You'll learn ways to grip and support items in order to do tasks safely with the least amount of stress on the finger joint. As with any surgery, avoid doing too much, too quickly. Eventually, you'll begin doing exercises designed to get your hand and fingers working in ways that are similar to your work tasks and daily activities.

The therapist's goal is to help patients improve strength, increase range of motion, and regain fine motor abilities with the hand and finger. When regular therapy is no longer required, the therapist can continue to be a resource. However, patients will be responsible for their ongoing home exercise program.