Background: Total Knee Arthroplasty (TKA) is becoming more common in morbidly obese patients (BMI greater than 40) and extremely obese patients (BMI >45). Novel cementless TKR design has shown favourable results over cemented TKA for morbidly obese patients but its performance in extremely obese patients is unknown.
Methods: A retrospective analysis of a national joint registry (New Zealand Joint Registry) was carried out. Stryker Triathlon Tritanium cementless TKA all cause revision rates were compared with Stryker Triathlon cementless TKA and non-Stryker cementless TKA for morbidly obese patients and extremely obese patients. Log-rank test was used for P-values.
Results: 4672 TKAs were recorded in the registry for morbidly obese patients and 1319 TKAs were recorded for extremely obese patients. 414 Stryker cementless TKAs for morbidly obese patients had a revision rate of 0.79 per 100 implant years with no statistically significant difference compared to the other two groups in morbidly obese patients, with a mean follow up of 2.34 years. 130 Stryker cementless TKAs had a revision rate of 1.91 in extremely obese patients, with no statistically significant difference compared to the other two groups. There were no revisions performed in Stryker cementless group for aseptic loosening or fracture.
Conclusion: Novel cementless TKA has comparable results to cemented TKA in extremely obese patients with no early aseptic loosening or fracture.
