Partial or Unicompartmental (Compartment-Specific) Knee Replacement

Partial Knee Replacement (Unicompartmental)

Partial Knee Replacement (Unicompartmental)

Unlike a total knee replacement, a unicompartmental or partial knee replacement only replaces one of the diseased compartments of the knee and not all 3. This preserves the undamaged parts of your knee. The common partial knee replacements done are the unicompartmental knee replacement for the medial (inside) compartment and the patellofemoral replacement for the patellofemoral (kneecap) compartment.

We do this via a minimally invasive approach through a small incision. Because there are less bone cuts and a smaller incision, patients recover very quickly and can be typically be discharged by the 3rd day after surgery. The other advantage of a partial knee replacement over a total knee replacement is a more “natural feeling” knee because unlike in a total knee replacement, the patient’s ligaments are preserved and not cut. Patients are also expected to regain their walking and knee bending ability much quicker. However, this surgery is only reserved for patients who do not have extensive damage to the knee- these patients would be better treated with a total knee replacement

Partial Knee Replacement
X-ray of a partial knee replacement (left) compared to a total knee replacement (right)


Partial knee replacements are technically more difficult to perform accurately compared to total knee replacements. Two recent innovations in surgical technique aim to improve the accuracy and precision with which we perform these surgeries:

1. Patient Specific Instrumentation (PSI) technology using customised cutting guides for partial knee replacement has been made available. This significantly enhances the surgical accuracy and simplifies the surgical process, cutting down surgical time and incision size.

2. And even more recently, Makoplasty, robotic assisted partial knee replacement has been made available in Singapore. Dr Lee is a Makoplasty-trained surgeon and currently performs his partial knee replacements with Makoplasty.

Pre-operative planning for Dr Lee’s PSI unicompartmental knee replacement patient