Will Osteoarthritis Behind The Kneecap Affect Your Partial Knee Replacement?

Nick London discusses his latest research and what it means for patients who need a partial knee replacement, but also have kneecap arthritis.

We often see patients who are candidates for a partial knee replacement who, in addition to wear (osteoarthritis?) elsewhere in the knee joint, also have quite substantial wear under the kneecap. This wear sits between the kneecap and the front of the knee, an area called the patello-femoral joint. Osteoarthritis here rarely causes significant symptoms but some surgeons, when they come across such patients, will cautiously exclude them from a partial knee replacement, opting for a total knee replacement instead.

Partial knee replacement the preferred option

For the past 20 years, I and others have been building a body of data to demonstrate the advantages of partial knee replacements (PKR) over total. We now know a PKR presents roughly a third of the operative risk of infections and blood clots compared with total replacements. On average, PKRs also deliver far better functional outcomes and patient satisfaction.

It would, therefore, be unfortunate if a patient who was otherwise an ideal candidate for a PKR was excluded from having it because they happened to have wear behind the kneecap.

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Does arthritis behind the kneecap affect the outcome of a partial knee replacement?

There is some evidence from surgeons using mobile bearing implants that shows patients with wear behind the kneecap, particularly on the inner half or central portion of the kneecap, rarely have problems when they have a partial knee replacement.

This has also been my experience, and recent research by myself, my YKC colleague Dave Duffy and others set out to confirm this, and to examine the effect with a fixed bearing implant. Our study looked at patient satisfaction scores and functional outcomes (that is, how well the knee performed) in 229 consecutive patients who each received the Persona Partial Knee implant, the best performing knee implant (partial or total) according to the National Joint Registry.

The study separated the patients with severe wear behind the kneecap from those who had a normal patello-femoral joint. We found no difference between the two groups, supporting the position that an isolated partial knee replacement is appropriate for the majority of patients with kneecap arthritis.

Long term study

These results are based on data from one and two years after operation. We’ll shortly begin collecting data as patients reach the fifth anniversary of their knee replacements, and will report on this in 2024.

Read the abstract here: https://www.isakos.com/GlobalLink/Abstract/4442

If you’re exploring your knee replacement options, contact us or phone us on 03453 052 579.

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