Revision of a unicompartmental (partial) knee replacement is an operation to convert a failed partial knee replacement to a total knee replacement. It is one of the advantages of partial replacement — revision to TKR is generally straightforward with good outcomes.
The previous incision is reopened or extended. The unicompartmental components (femoral and tibial) are removed. The remaining joint surfaces are prepared. Standard primary total knee replacement components are typically sufficient — revision-type implants with stems are only needed if there is significant bone loss. Bone defects are filled with cement, graft, or augments. The operation takes one and a half to two hours.
Revision is needed for loosening of the unicompartmental components, polyethylene bearing wear, progression of arthritis in the other compartments, persistent unexplained pain, infection, or fracture around the implant.
For pain without loosening: physiotherapy, injection, investigation for other causes. For confirmed mechanical failure: revision is usually required.
X-rays, CT if bone loss suspected. If infection suspected, aspiration first. Assessment of the cause of failure guides the revision plan.
Good outcomes — revision of UKR to TKR generally produces results comparable to primary TKR. This is one of the key advantages of choosing UKR initially.
Hospital stay one to three days. Full recovery six to twelve months.
Temporary. Physiotherapy essential.
Removing the UKR may reveal bone defects requiring augmentation.
Higher risk than primary TKR, approximately 2–3%.
Ligament balancing may be more challenging.
DVT/PE.
Periprosthetic fracture.
General or spinal anaesthesia.
Same as primary TKR. Hospital one to three days. Physiotherapy from day one. Driving at six weeks. Full recovery six to twelve months.
Same as primary TKR: reviews at two weeks, six weeks, three months, one year.
Yes — evidence shows that revision of UKR to TKR produces results comparable to primary TKR. This is a significant advantage of choosing partial replacement initially.