Proximal Interphalangeal (PIP) Joint Injuries

The proximal interphalangeal joint is the middle joint of your finger. It is an unforgiving joint when injured, and often becomes extremely stiff. What most people don’t realize is that the bones of the fingers heal extremely quickly, and if this joint suffers a severe injury it can become irreparable within only 2-3 weeks. That’s a good reason to see a hand surgeon quickly following a proximal interphalangeal joint injury.

If the proximal interphalangeal joint becomes dislocated, without a fracture, these are almost always stable injuries. Splinting them is often counterproductive, because it leads to stiffness. This stiffness can become severe enough within 3-4 weeks so that nothing short of a surgical release will allow motion to regained. However, if motion is begun early an almost normal joint can be regained, with full function.

An unfortunate, but common enough scenario is that there is a proximal interphalangeal joint fracture-subluxation. That means that a critical part of the joint is broken (fractured), which allows the joint to sublux (partially dislocate). This leads to pain and stiffness. If not treated, arthritis often ensues within 6-12 months, or sooner. Even after optimal treatment, the joint will never be the same. The joint will always be thick, may have tenderness and ache sometimes (like when the weather changes) and will never regain full motion.

Proximal interphalangeal joint fracture-subluxations are difficult injuries to treat early, and late treatment is even more problematic. The priorities for early treatment of proximal interphalangeal joint fracture-subluxation are 1) Reduce the joint subluxation so that the joint is located. Failure to do this essentially guarantees early arthritis, 2) Obtain joint motion. Otherwise, the joint becomes extremely stiff, 3) And this priority is, by far, the least important of these three goals: try to reduce the joint fragments. Please note that this is not always possible, and that many people can do well without the joint fragments reduced, as long as the first two goals are met.

The fracture part of these injuries is often highly comminuted, meaning that it is made up of many very small fragments than cannot be reduced (placed back into good position) by opening the fracture directly. Relying only on open surgery to reduce these fractures often has a high rate of stiffness and suboptimal results.

The best treatment of an acute (<1-2 week old) proximal interphalangeal joint fracture-subluxation to accomplish at least the first two goals is a “dynamic external fixator”. This is a device constructed of wires and rubber bands in the operating room. The one that I prefer was invented by my late friend, Joe Slade, MD. Many comment that it looks somewhat like a radio antennae coming out of the finger. While that is true, it’s the best technique that I have found for treating early proximal interphalangeal joint fracture-subluxations. While no surgery, especially for severe injuries such as these, works 100% of the time, this one consistently reduces the joint and allows for early motion (with the help of post-operative hand therapy, which is extremely important). A small open incision often allows for reduction of the joint fragments.

Slade dynamic external-fixators usually need to be worn for 6 weeks. And they need to be taken care of. It is extremely important that the patient be responsible in looking after these. These require protective splints over them all the time except bathing or performing motion exercises to prevent them from catching on clothes, surrounding people or objects. The wires cannot be allowed to get bent. Extra rubber bands need to always be carried in case one breaks. Follow-up X-rays are taken every week to start, then every two weeks. Therapy sessions must be attended and “homework” performed to regain motion. The fixators are removed in the office, usually after 6 weeks. This does not hurt very much, and is nothing to worry about.

If the proximal interphalangeal joint fracture-subluxation is not seen within 1-2 weeks, the Slade dynamic external fixator can often be used, but now the joint often has to be opened to clean out scar tissue and allow the joint to reduce. This creates more scar and the ultimate result is often not as good. After 4-6 weeks, the proximal interphalangeal joint fracture-subluxation cannot be fixed, and needs to be reconstructed (replaced).

The best reconstruction, in most cases, is a hemi-hamate arthroplasty. This involves removing a portion of the hamate (a wrist bone) with its cartilage and using it to replace the destroyed proximal interphalangeal joint surface through an open incision. While it probably works better than the other options for proximal interphalangeal joint fracture-subluxations presenting late, the joint often becomes stiff, and the results are not nearly as good as for early injuries treated by the Slade dynamic external fixator. Remember that scar has formed before the surgery, and the original joint surfaces are now destroyed. Some amount of arthritis is often present by this time.

Once significant arthritis has occurred, treatment options are limited to joint replacement or fusion. Both of these are salvage options. Newer options for joint replacement work better, but no artificial joint can ever be as good as your natural joint. Therefore, it’s best to get these injuries treated early to have the best chance at a good result.

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