A Comparison of the Periprosthetic Fracture Rate of Cemented and Cementless Total Knee Arthroplasties: An Analysis of Data From the National Joint Registry.

BACKGROUND: Periprosthetic fractures are serious complications of knee arthroplasty often requiring complex surgery. There is concern of increased periprosthetic fracture risk with cementless components given the reliance on interference fit for primary stability. It is unknown how the periprosthetic fracture risk compares between cemented and cementless total knee arthroplasties (TKAs). METHODS: A total of 22,477 cemented and 22,477 cementless TKAs from the National Joint Registry and Hospital Episodes Statistics database were propensity score matched on patient and surgical factors. Cumulative periprosthetic fracture rates were calculated using Kaplan Meier analyses and compared with Cox regressions. Subgroup analyses were performed in different age, body mass index (BMI), and sex groups. RESULTS: The three-month fracture rate in the cemented and cementless TKA groups were 0.02 and 0.04%, respectively. At 10 years, the cumulative fracture rate after cemented TKA was 1.2%, and after cementless was 1.4%. During the study period there were no significant differences in fracture rates between cemented and cementless TKAs with a HR 1.14 (Confidence Interval 0.94 to 1.37, P=0.20) at 10-years postoperatively. There were no significant differences in fracture rates between fixation types on subgroup analyses of sex, BMI and age groups. Women were at risk factor for fracture in both cemented (Odds Ratio (OR) 2.35, P<0.001) and cementless TKAs (OR 2.97, P<0.001). CONCLUSIONS: The periprosthetic fracture rates following cemented and cementless TKA surgery are low being approximately 1.2 and 1.4% respectively at 10-years. There were no significant differences in periprosthetic fracture rates requiring readmission between cemented and cementless TKAs. LEVEL OF EVIDENCE: III.