Distraction arthroplasty? Not a term you may have heard before. Not one that I was familiar with either, and I think this is probably true for most other orthopaedic surgeons as well. During my residency I only heard it discussed once in passing, and if not for my interest in joint preservation and reconstruction, I don't think I would have heard about it again.
In general terms, distraction arthroplasty or simply "joint distraction" is a surgical procedure that uses an external fixator (frame) to "pull apart" a joint. This technique is used to help repair damage in a joint affected by arthritis, especially in young people for whom joint replacement or fusion are not good options. A common scenario that I have seen is a 30-something year old patient with debilitating ankle arthritis because of a prior ankle fracture. They have generally seen multiple specialists, and have been told that bracing and occasional steroid injections or ankle fusion are the only options. (Replacement is not recommended in young patients because of high failure rates.)
However, ankle distraction is a good option for this type of patient. It preserves motion (unlike a fusion) and preserves the native cartilage (unlike a replacement). We can go into more specifics about this procedure in a future posting, but basically an external fixator is surgically placed after the joint is "cleaned up" (bone spurs removed and bare areas of bone are addressed, and then stem cells from the patient's bone marrow are added), and worn by the patient for 3 months. After three months the frame is removed and physical therapy is started. Most patients see an improvement by 3-6 months, but improvement continues out to 2+ years. This is important to keep in mind, because this procedure is not a quick fix, but rather an investment in preventing or delaying the need for future surgeries.
Joint distraction is still a relatively new procedure, so the exact mechanisms of how it works are not completely understood, however research has demonstrated that there is definitely regeneration of cartilage - something that was previously thought to not be possible. It is thought that by unloading the joint with distraction, the body's natural ability to heal cartilage is enhanced. Think of it this way - a road that is full of pot holes, but always clogged with heavy traffic is very difficult to repair. Patches can be done, but never hold up - those pot holes always come back, and the road slowly decays. Now imagine what happens when that road is closed for repairs. Proper patching and repaving can be done without being disrupted. Now the road can reopen and stand up to heavy traffic again without falling apart. This is essentially what happens in the joint (in this case we were talking about the ankle, but exciting new research regarding using this procedure for knee arthritis is coming out now too!).
I will explain more about the procedure in future posts, and can including some research and followup data regarding how patients do long term. But for now, I will leave you with the before and two year post procedure x-rays of a young man who suffered an ankle (talus) fracture, which lead to debilitating arthritis. I just saw him a few weeks ago with one of my fellowship mentors, and he said that this procedure "changed his life". As you can see in the picture below, the bone spurs that were removed have not returned, and he has maintained an larger joint space (i.e. more cartilage cushion) over those two years since his frame was removed.
Case courtesy of S Robert Rozbruch, MD