In my practice, I see many patients come to the office asking if they can have a partial knee replacement due to wanting a smaller operation and quicker recovery. Here I will run through the pros and cons of a Total vs Partial knee replacement.

The knee can be considered to have 3 compartments that may require replacement (medial, lateral and patella) and a partial knee replacement only replaces the diseased compartment, which is most commonly on the medial side of the knee. A total knee replacement replaces all 3 compartments. The Australian Joint Registry shows that partial knees accounted for 15.4% of all knee replacement surgery in 2003, dropping to a low of 4.4% in 2015. The reason for the decreased use of partial knee replacement was the rate of conversion to a total knee replacement was 2 to 3 times higher than the revision rate of a total knee replacement. However it is well shown that a patient with a painful partial knee (without obvious cause for failure) are more likely to be offered conversion surgery than patients with a painful total knee replacement, accounting for a significant percentage of this increased rate.

However the conversion rate is gross data that only tells part of the story. Extensive research from Oxford has shown many benefits that are unique to partial knee replacement. We are moving into an era where patient satisfaction is the number one goal and dissatisfaction rates with partial knee replacement are half of total knee patients. Clinical scores and function are higher in partial knee replacement due to more natural kinematics (movement) of the knee. Major complications such as infection, heart attack, stroke and death are approximately 50% lower in partial knee replacement. Anecdotally patients much prefer partial knee replacement. For these reasons partial knee replacement increased in usage by 16% in previous 12 months.

In summary partial knee replacement has a slightly higher rate of conversion than a total knee replacement, with less surgical risk and superior clinical function. To be a candidate for partial knee replacement you require isolated arthritis (can you localise your knee pain with 1 finger?), a functional ACL ligament and less than 10 degrees of deformity. If you meet this criteria, the majority of patients will experience 20 years or more of excellent function from a partial knee replacement.