No difference in gait between posterior cruciate retention and the posterior stabilized design after total knee arthroplasty.

PURPOSE: In the present study, knee joint kinematics (e.g. knee flexion/extension) and kinetics (e.g. knee flexion moments) are assessed after total knee arthroplasty (TKA) between patients implanted with either a unilateral posterior stabilized (PS) and a posterior cruciate-retaining (PCR) design. It was hypothesized that maximum knee flexion during the loading response of the stance phase is greater in patients implanted with a PS design than in patients with a PCR design. Secondarily, it was hypothesized that patients with a PS design show decreased knee flexion moments during loading, compared with patients implanted with a PCR design. METHODS: This study examined two groups of TKA patients: one group (n = 12) with a PS design in which the posterior cruciate ligament (PCL) was sacrificed and the other (n = 9) with a PCR design. Gait analysis was used in level walking before and 6-9 months after surgery, to assess knee joint kinematics and kinetics during the loading response of the stance phase. RESULTS: No significant differences in maximum knee flexion between the two groups were found during the loading response of the stance phase. No significant differences in knee flexion moments were found either. Although in both groups knee flexion moments increased postoperatively, this was not statistically significant. In the contralateral (nonimplanted) knees, all mean knee flexion moments decreased postoperatively for both groups, yet this was not significant. CONCLUSIONS: The present gait analysis study showed no differences in kinematics and kinetics between the PS and the PCR TKP design. This might suggest that surgeons do not necessarily need to substitute the PCL by a PS design during TKA. LEVEL OF EVIDENCE: Prospective comparative study, Level II.