Medial Pivot knee implants reduce noise and improve satisfaction

Knee implants that generate less noise are linked to higher patient satisfaction, especially with Medial Pivot designs.

Following a total knee arthroplasty (TKA), some patients report unexpected noises (clicking, popping, or squeaking) coming from their new joint. These sounds, while generally not dangerous, can impact patient satisfaction and confidence in the surgical outcome.

A recent study titled "Medial Pivot prostheses generate less noise than mobile bearing and cruciate retaining total knee arthroplasties" explored this phenomenon by comparing how often different prosthetic designs produce noise.

Comparing the three prosthesis types: MP, MB and CR

This retrospective comparative study assessed 200 patients who underwent TKA between 2020 and 2022, all with a minimum follow-up of two years. Researchers analysed three different implant designs:

• Medial Pivot (MP) – Microport®
• Mobile Bearing (MB) – Amplitude®
• Cruciate Retaining (CR) – Stryker®

Patients completed several validated scoring tools to evaluate satisfaction and knee function: the IKS (International Knee Society) scores, SKV scores (a patient-reported outcome scale), a satisfaction questionnaire and the Kuriyama noise-specific questionnaire.

What the data shows

Results revealed a notable difference in the frequency of perceived noise among the three implant types:

• In the Medial Pivot group, 74.5% of patients reported no noise.
• In contrast, 61.4% in the Mobile Bearing group and 62.1% in the Cruciate Retaining group reported silent knees.

Overall, 32% of the patients in the full cohort experienced some form of noise. While not clinically harmful, these sounds were associated with lower satisfaction scores.

Noise and satisfaction: why silence matters

Although the differences in functional scores (such as the IKS function score) were not statistically significant, patient satisfaction did show a correlation with the presence or absence of noise.

• Patients with silent knees were more often classified as very satisfied or satisfied (93%).
• Those with noisy knees showed a lower satisfaction rate (84%).
• This difference was statistically significant (p = 0.02).

The average SKV score was also slightly higher in the silent group (81.8) compared to the noise group (75), although this difference was not statistically significant.

Why is this important for patients?

A prosthesis that feels (and sounds) more natural may boost the overall confidence of the patient, helping them better trust the operated knee during daily activities or rehabilitation. Even in the absence of pain or mechanical failure, subtle cues like joint sounds can influence how patients perceive their recovery

Results from the study

At two years post-operation, Medial Pivot implants appear to be less likely to generate noise than Mobile Bearing or Cruciate Retaining designs, with a measurable impact on patient satisfaction. While more research is needed to explore the underlying causes of these acoustic differences, this study suggests that prosthetic design plays a non-negligible role in the perceived outcome of TKA.

For expert care in knee replacement and orthopaedic procedures, put your trust in Professor Étienne Cavaignac. His experience and patient-centred approach ensure that every surgical decision is based on both outcomes and comfort.

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