One of the most commonly performed orthopedic surgeries is a total knee arthroplasty (knee replacement). Currently, there approximately 700,000 knee replacement procedures done every year in the US. By some estimates, this is projected to increased to almost 3.5 million procedures by the year 2030. Knee replacement surgery consistently ranks near the top of the list of most commonly performed surgical procedures each year in the United States.

Persistent pain after a total knee arthroplasty represents a growing problem. Approximately 40% of patients who undergo knee replacement surgery report at least some type of chronic discomfort. A full 15% of these patients will rate their pain as “severe to extreme.” Using current numbers, this means that just over 100,000 people a year are left with “severe to extreme” pain in the knee that has just undergone total joint replacement.

While the majority of chronic joint pain is usually due to some type of underlying orthopedic problem such as advanced arthritis, this is not always the case. There is often a complex series of nerves associated with the major joints in the body. Some of these nerves may be large nerves transiting through the area on their way to another part of the body. Some nerves may be sensory to the joint structures, and still other nerves may be sensory to the skin and deeper soft tissue surrounding the joint itself. These nerves are all susceptible to damage or compression from a variety of different injury mechanisms.

Surgery on the knee joint, whether it is an arthroscopic meniscus repair or a total knee arthroplasty carries with it a small but significant risk of damage to one or more of these nerves. The trauma to the soft tissue envelope surrounding the knee joint causes swelling, inflammation and scarring that can entrap nerves causing severe pain with motion of the joint. In addition, the smaller sensory nerves in the area of the knee joint are often inadvertently cut or crushed during the process of replacing the knee joint or inserting the trocar into the joint space in the case of an arthroscopic procedure. This can lead to the formation of a neuroma (a painful ball of sensitive nerve ends mixed with scar tissue) that will then simply serve to send constant pain signals to the person’s brain.

Many patients who end up in this situation undergo multiple additional orthopedic knee surgeries including revision after revision before finally being consigned to the pain management realm. Once the pain generator is a damaged sensory nerve, it doesn’t matter how many additional orthopedic surgeries the patient has, the pain will not get better and frequently can be made worse.

A detailed understanding of the nerve anatomy around joints provides the option of a “joint denervation procedure,” where the damaged nerves can be located and disconnected upstream from the area of injury. These nerves can then be handled in specific ways to prevent additional inappropriate stimulation and the formation of painful neuromas. This serves to shut off the pain signal to the patient’s brain and eliminate the sensation of pain in the knee area. This simple approach can be applied to many other situations involving chronic joint pain including shoulders, elbows, wrists, and ankles.