If you have rheumatoid arthritis, chances are you have read a thing or two about the replacement of the hip and knee joints, right? Elbow replacement is less common, but patients with really bad rheumatoid elbow involvement are good candidates for this procedure. Previously, we reviewed the spectrum of treatment options for elbow rheumatoid arthritis. Today, we will discuss elbow replacement in more detail.
How is the elbow joint replaced?
Three bones form the elbow joint: the humerus in the upper arm, and the radius and the ulna in the forearm. Total elbow replacements provide new articulating surfaces for the humerus and ulna; some replacements also provide a new articulating surface for the radius. The artificial parts used for replacement, known as implants or prostheses, are typically fixed with a small layer of grouting called “bone cement” or “polymethylmetacrylate”. These implants are made of a metal alloy. The articulation itself incorporates a bearing surface fabricated with a special kind of plastic called “polyethylene”. The implants used to replace the humerus and ulna can be linked with a coupling mechanism. Alternatively, they can be implanted in an unlinked fashion, provided the ligaments and bone structure necessary for joint stability are not compromised by the rheumatoid inflammatory process.
At the time of replacement, the elbow joint is typically accessed from the back. The bones are separated and prepared to receive the implants. The humeral implant includes a flange that provides additional fixation. A small piece of bone from the elbow is sandwiched between the flange and the front of the humerus bone.
The importance of the triceps
For surgeons, accessing the elbow joint from the back presents a little problem: the triceps muscle and its tendon attachment to the ulna are in the way! There are two basic ways to get access to the joint from the back: detaching the triceps or working around it. When surgeons detach the triceps to perform the replacement, the term “triceps off approach” is used; “triceps on approach” means that the replacement was performed working around the triceps.
The main issue with “triceps-off” exposures is that in some individuals the triceps tendon will not heal; if that is the case, patients will experience weakness when trying to straighten their arm. Obviously, “triceps-on” exposures prevent weakness, but the operation is more difficult to perform and requires more extensive dissection, which could lead to problems with healing of the skin incision or cut.
Why am I being told I may have numbness in my hand after the procedure?
There are several nerves that travel close to the elbow joint as they descend through the arm. One of them in particular, called the ulnar nerve, pretty much sits behind the elbow and runs through the elbow joint. This is the nerve that tingles when a you accidentally hit your elbow (also known as the “funny bone”). The ulnar nerve must be moved out of the way to some extent in order to perform an elbow replacement safely. Nerves are so sensitive that in some patients, the nerve will not function normally after the nerve is transposed. That is why some patients feel numbness and tingling in the ring and pinky finger after surgery. Most of the time, normal feeling returns within weeks or months but occasionally, the abnormal feeling is permanent. Ulnar nerve damage can lead to hand weakness or clumsiness after surgery, but this is very rare.
What is the recovery like?
After replacement, our preference is to immobilize the arm in a fully extended position with a splint placed in the front. The elbow should be kept elevated. Sometimes, the nerves that supply feeling to the elbow are temporarily blocked right after surgery by injecting a local anesthetic; little or no pain is felt while the block lasts, typically several hours to one day. Motion exercises start 2-5 days after surgery. If the operation was performed with a “triceps-off” approach, patients are advised to avoid pushing with their arm fully extended for six weeks after surgery. Most patients feel completely recovered three months after surgery. After elbow replacement, getting the elbow fully straight is very difficult to achieve, but most patients experience complete pain relief, good motion and stability.
How much can I use it? Is it gonna last?
Since the elbow joint is relatively small compared to larger joints like the hip or the knee, the implants used for elbow replacement are smaller and to some extent more delicate. Excessive use of the elbow after replacement can lead to wear of the plastic bearing or loosening of the components off the bone. Obviously, when that happens the elbow joint hurts again and further surgery may be required to exchange the worn or loose implants. The good news is that our experience indicates relatively low failure rates for several years after surgery in patients with rheumatoid arthritis [Primary TEA in RA].
In general, it is recommended to avoid heavy lifting after replacement. Carrying objects with the elbow straight is safer, but lifting while bending, or pushing and pulling strongly is not advised.
A word about infection
One of the most devastating complications of elbow replacement is infection. Unfortunately, patients with rheumatoid arthritis are at an increased risk, partly due to the immune nature of their condition, and partly due to some of the medications used to treat rheumatoid arthritis. If you need your elbow replaced, please share with your doctor all the medications you take. Some medications will need to be discontinued for some time around the time of surgery. Your rheumatoid arthritis may flare up while these medications have been discontinued, but believe me, you do not want your elbow to get infected. That is why the #1 priority after surgery is for your skin incision to heal. If deep infection does happen, one or more surgeries are almost always needed, and the outcome is never the same.
If you want to learn more… Rheumatoid elbow surgical treatment options