Patellar Resurfacing — To Do or Not to Do?

Part of The Joint Replacement Guide — Phase 4: The Operation · Article 25 of 42 · Knee

Key Points

• During knee replacement, the surgeon can choose to resurface (replace) the back of the kneecap with a plastic component, or leave the kneecap’s own bone surface as it is.
• This is one of the most genuinely debated decisions in knee surgery, without a single clear-cut answer for every patient.
• Large trials have found broadly similar overall outcomes between the two approaches, though each carries slightly different specific risks.
• Practice varies between surgeons and countries, reflecting genuine ongoing uncertainty rather than one approach being clearly wrong.

What Patellar Resurfacing Involves

The kneecap (patella) has its own cartilage-covered surface that glides over the front of the thigh bone as you bend and straighten your knee. During a total knee replacement, a surgeon can choose to remove this surface and replace it with a plastic (polyethylene) button, cemented in place — this is patellar resurfacing — or leave the kneecap’s natural bone surface untouched, relying on it to glide against the new metal implant on the thigh bone.

The Case for Resurfacing

Proponents argue resurfacing reduces the chance of ongoing anterior (front of knee) pain arising specifically from the kneecap after surgery, since any remaining arthritis on the unresurfaced natural patella could theoretically continue to cause symptoms even after the rest of the knee has been replaced.

The Case Against Resurfacing

Those who favour leaving the patella unresurfaced point out that it avoids specific risks unique to the resurfaced component itself — including patellar fracture (mentioned in the earlier article on TKR-specific risks) and, rarely, the plastic button wearing loose or loosening from the bone — and that large trials have generally failed to show a clear, consistent difference in overall pain or satisfaction between the two approaches at a population level.

What This Means in Practice

Practice varies considerably between individual surgeons, hospitals, and even countries — some surgeons resurface routinely, others rarely, and many decide on a case-by-case basis depending on the appearance and condition of the patella they find during surgery. This variation genuinely reflects ongoing scientific uncertainty rather than any approach being clearly incorrect, and it’s entirely reasonable to ask your surgeon what their usual practice is and why.

In More Depth

Several large randomised controlled trials, including large UK-based studies, have specifically compared resurfacing against non-resurfacing and generally found no statistically significant difference in patient-reported outcomes at follow-up, though a minority of patients in the non-resurfaced groups in some trials have gone on to need a second, later operation to resurface the patella because of ongoing symptoms. This is one of the relatively rare areas of knee replacement where the highest-quality trial evidence available still doesn’t point clearly in one direction, which is itself a useful, honest thing for patients to understand — not every surgical decision has a single scientifically “correct” answer, and reasonable, well-informed surgeons can and do differ.

This article is general information and does not replace individual clinical advice.

Sources

• Cochrane Database of Systematic Reviews — patellar resurfacing in total knee replacement
• National Joint Registry — Annual Report, patellar resurfacing rates and outcomes
• British Association for Surgery of the Knee (BASK) — patellar resurfacing guidance

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