Cementless TKA vs Cemented in Morbidly Obese Patients…New Data

A new study from the University of Louisville Adult Reconstruction Program has collected survivorship data for both cementless total knee arthroplasty (TKA) and cemented TKA in morbidly obese patients. The data is in a new study which appears in the February 2019 edition of the Journal of Arthroplasty.

The retrospective study, “Increased Survivorship of Cementless versus Cemented TKA in the Morbidly Obese. A Minimum 5-Year Follow-Up,” was co-authored by Arthur Malkani, M.D. of the University of Louisville Adult Reconstruction Program.

Dr. Malkani explained the issue that he and his colleagues were expecting to address in the study. “We were seeing higher failure rates following primary cemented TKA in our morbidly obese patients and young active males due to aseptic loosening despite well aligned knees.”

The authors compared five-year survivorship data for 108 morbidly obese patients (BMI ≥ 45.6) who’d received a cemented primary TKA with 85 morbidly obese patients (BMI = 45) who’d received a cementless TKA.

They found: “There were 5 failures requiring revision in the cementless group, including 1 for aseptic tibial loosening. In the cemented group, there were 22 failures requiring revision, including 16 implants for aseptic loosening. Survivorship with aseptic loosening as the endpoint was 99.1% in the cementless group vs 88.2% in the cemented cohort at 8 years.”

Dr. Malkani summarized the data from this study to OTW, “Our results demonstrated that survivorship with aseptic loosening as the end point was 99% using a modern design cementless total knee arthroplasty compared to 88% in the cemented cohort at eight years.”

“Morbidly obese patients have a higher failure incidence due to aseptic loosening with cemented TKA with decreasing survivorship over time. The use of cementless TKA using a modern design implant in the morbidly obese with the potential of durable long-term biologic fixation and increased survivorship is an excellent alternative to the use of mechanical cement fixation.”

“Current design cementless TKA are not the same as past generation cementless implants which had poor tibial baseplate-polyethylene locking mechanisms and utilized polyethylene with poor wear characteristics. Similar to the success of cementless THA [total hip arthroplasty], modern design cementless TKA demonstrate excellent clinical results with durable biologic fixation and increased survivorship compared to cemented TKA in the morbidly obese.”