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Metal release in the knee: A greater burden than suspected?

An interdisciplinary US team – including Clemson University’s Jeremy Gilbert, PhD, Drexel University’s Steve Kurtz, PhD, and the University of Tennessee’s William Mihalko, MD, respectively in Clemson, Philadelphia, and Memphis – have studied the mechanisms that cause the deterioration of cobalt-chrome-molybdenum (CoCrMo) and titanium components in total knee arthroplasty (TKA) and releasing metal ions in vivo. They conclude that ALTRs, electrocautery damages, and other damages may interfere as dangerously in primary TKA implants as in hip implants.

🔎 The analysis included 50 retrieved CoCrMo femoral knee implants from different manufacturers, all revised at Cleveland Clinic. The object was to determine how – and how often – CoCr ions were released in the knee.

 

The team assessed bearing wear via a specialized semi-quantitative scoring system and classified types of damage via digital optical microscopy (DOM), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS).

 

💡 Three main damage modes were identified: wear, electrocautery damage, and material transfer. All three presented strongly:



➡️ wear on the bearings of all 50 implants,

➡️ electrocautery damage in 98% of implants, and

➡️ Ti-6Al-4V material transfer to the posterior condyles on 23 of the 39 implants with titanium-alloy baseplates

 

Despite the low number of retrievals, the authors suggest that these damage modes and mechanisms are more common than previously thought and may facilitate the release of metal ions in vivo, prematurely shorteningthe lifespan of the implant and increasing the risk of revision surgery. 

 

These findings – in combination with a recent study by Rajamäki et al. which reported ALVAL in 30% of revision knee patients – provide a possible explanation for the continuing dissatisfaction of primary TKA recipients despite reported clinical success.

 

 

Disclaimer: Research funded by CeramTec

Pictures: Permission Steven Kurtz PhD

References:

Kurtza,b, Peter W., Michael A. Kurtza,b, Shabnam Aslanic, Lilliana M. Taylora,b, Charley M. Goodwina,b, Daniel W. MacDonaldc, Nicolas S. Piuzzid,e, William M. Mihalkof, Steven M. Kurtzc, Jeremy L. Gilbert.a,b “Wear, Material Transfer, and Electrocautery Damage are Ubiquitous on CoCrMo Femoral Knee Retrievals.”

Rajamäki, A., Lehtovirta, L., Niemeläinen, M., Reito, A., Parkkinen, J., Peräniemi, S., ... & Eskelinen, A. (2024). Mild aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL)-type reactions also present in patients with failed knee prostheses. Bone & Joint Research, 13(4), 149.

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