We discuss the article: "Prosthetic Arthroplasty Versus Arthrodesis for Osteoarthritis and Posttraumatic Arthritis of the Index Finger Proximal Interphalangeal Joint" recently published in Journal of Hand Surgery (See full article)
Arthritis is the breakdown of cartilage within our joints. Every healthy joint has cartilage because it acts as both shock absorber and lubrication to allow smooth gliding motion. Over time our cartilage can wear out and it doesnt grow back. This occurs in every joint in your body, but at different rates. Most of the joints' cartilage out-lives us, but if we lived to 200 years old, we would probably be stuck in bed due to terrible arthritis in all of our joints. In reality, our hips and knees most commonly develop arthritis in our lifetime and require thus knee or hip replacements. But certain factors like traumatic injury to a joint (like one of your knuckles) can accelerate the rate of cartilage wear, causing it to become prematurely arthritic.
Arthritis causes pain because of increased friction caused by bones grinding on each other during joint movement. The solution for arthritis is to replace the joint's cartilage with metal or plastic...this prevents the bones from grinding on each other, and this is called a joint replacement. The other solution is to fuse the joint to remove all motion...this prevents bones from grinding (the cant move) and thus they arent painful.
In the hip or knee, the fusion option creates major problems with daily function (you essentially give someone a "peg leg") and therefore almost all patients do better with a replacement.
However, the hand has so many small joints, that fusing a single painful joint doesnt cause the same dramatic functional problems... your other fingers can compensate. Additionally, there has been less research and development into the tiny joint replacements for the fingers and therefore one could argue that the technology is not as good as a hip or knee replacement. So both options are available to patients without a clear picture of which one is better. This article attempted to answer that question by comparing the results of these options.
65 patients received a joint replacement ("arthroplasty") while 18 patients received a fusion ("arthrodesis"). Even though patients with a fusion lost all motion at that joint in their finger, they reported equal satisfaction, equal improvement in pain, and overall equal function compared to the joint replacement group. Even though both surgeries produced equal levels of function, the joint replacement group had a much higher complication rate (4 times higher), with higher rates of repeat surgery.
One possible reason for the better results for the fusion group in this study was that it examined arthritis in the index finger alone. The index finger is highly involved in "pinch" movements of the hand, and fusion may provide a more stable base for this important action. Just because fusion appears better in this study, does not mean its better for all of the fingers.
References
Sweets TM, Stern PJ. Pyrolytic carbon resurfacing arthroplasty for osteoarthritis of the proximal interphalangeal joint of the finger. JBJS 2011; 93: 1417-1425. see article.
Adams J et al. Proximal interphalangeal joint replacement in patients with arthritis of the hand: a meta-analysis. JBJS Br 2012; 94: 1305-1312. see article.