A partial knee replacement is an excellent long term and durable reconstruction for treating bone-on-bone arthritis in the knee that is localized to just one area of the joint. There are certainly many potential advantages to a partial knee replacement, for those who are a candidate, and this has been covered in other blog topics that we have discussed. In general, a partial knee replacement should last as long as a full knee replacement would, and a partial replacement is not meant to be done as a “bridge” to a full knee replacement later. Patients can typically expect years or decades of excellent function and pain relief from a partial knee replacement, but eventually additional wear and tear can lead to the need for additional treatment of your knee. The definitive treatment for a failed partial knee replacement, if all conservative treatments have failed, is typically to convert or change the partial knee replacement to a total knee replacement, but there are different indications for doing this.
Let’s talk about some of the ways in which a partial knee replacement may wear out or require revision surgery:
Arthritis Develops or Worsens in Existing Bone
Over time, a knee that has been repaired with a partial knee replacement can wear out. A partial knee replacement often wears out because the remaining natural surfaces in the knee that were not replaced have finally worn away. Over many years or decades, developing progressive arthritis in the remaining natural parts of knee could ultimately be a source of pain that is similar to knee arthritis in general.
Prosthetic Pieces Become Loose from the Bone
Partial knee replacements can loosen over time from the bones they are attached to. In other words, the glue or grout that connects the prosthetic knee parts to your bones can weaken or disconnect.
This often creates the classic “start-up pain,” whereupon rising from a seated position creates moderate to severe pain in the joint. As you walk, gravity and pressure can re-seat them in position and the pain may lessen somewhat.
Ligaments Loosen and Create Instability
The anterior cruciate ligament (ACL) and other ligaments in the knee must be strong and healthy for a partial knee replacement to work properly. If the natural ligaments no longer tightly support and hold the knee in place, you can develop instability in your knee. This can lead to swelling, buckling, and pain.
Infection Loosens Natural Components
An infection can spread to any type of joint replacement and be a cause of pain. It can also cause loosening of a partial knee replacement, because the natural parts are weakened from the infection and no longer fully support the prosthetic parts. The treatment of infection in a joint replacement can be very complicated because the infection needs to be cured prior to any type of revision procedure.
Wear-and-Tear of Prosthetic Materials
The mechanical portions of a partial knee replacement can eventually wear out just as the natural portions of the knee that were replaced did. The gliding surface of the new replacement can wear away in a similar manner as how tire treads wear down over time. The partial knee prosthesis is modular – so if the rest of the partial knee replacement is in good shape, the gliding surface can later be switched out as necessary – just like changing a tire on your car.
Knee Replacement Surgeon in Raleigh-Durham
If you live in the Triangle area – Raleigh, Durham, Chapel Hill – and have chronic pain in one or both of your knees, don’t let it interfere with your active lifestyle. Duke medical school and Duke orthopedic graduate, and Rush fellowship-trained joint replacement surgeon Dr. Brett Gilbert specializes in replacing only the parts of your knee that are worn and require treatment, keeping the healthy parts of your own knee and helping you to recover as quickly as possible.