Tibial rotation kinematics subsequent to knee arthroplasty.

BACKGROUND: The use of computer assisted joint replacement has facilitated precise intraoperative measurement of knee kinematics. The changes in "screw home mechanism" (SHM) resulting from Total Knee Arthroplasty (TKA) with different prostheses and constraints has not yet been accurately described. METHODS: A pilot study was first completed. Intraoperative kinematic data was collected two groups of 15 patients receiving different prostheses. RESULTS: On average, patients lost 5.3° of ER (SD = 6.1°). There was no significant difference between the prostheses or different prosthetic constraints. CONCLUSIONS: There significant loss of SHM after TKA. Further research is required to understand its impact on patient function.