Ambient theatre temperature and cement setting time in total knee arthroplasty

Polymethylmethacrylate cement is used in total knee arthroplasty and plays a significant role in the success of the procedure. Temperature variation is known to influence cement setting time in vitro. Our aim is to evaluate the relationship between ambient theatre temperature and cement setting time in vivo.

Theatre temperature and cement setting time were prospectively recorded during 683 total knee arthroplasties over 8 years using a single cement and vacuum mixing system (Simplex with tobramycin). Setting time was defined as the time until a scalpel blade could not indent the cement surface.

Mean temperature was 18.92°C (SD 1.16) and setting time 13.08 min (SD 1.92). A moderate inverse relationship exists between ambient temperature and setting time (Pearson's R = -0.423); however, potential setting times within a given temperature range varied considerably (<19°C: 8-19.1 min, 19-20°C: 7-18 min and >20°C: 7.5-16 min), suggesting that temperature alone cannot reliably predict setting time.

Our data support the current understanding of bone cement properties in vivo and suggest that surgeons should be mindful in regards to unpredictable cement setting time and optimal theatre environment.