Description
Objectives: Patients who undergo total knee arthroplasty (TKA) with inverse kinematic alignment (iKA) tend to report higher satisfaction levels compared to those with adjusted mechanical alignment (aMA). However, these observations require validation through biomechanical studies that examine gait and everyday functional movements. This study aimed to compare the performance of forward lunge between a group of patients who received iKA and a group who received aMA.
Methods: The investigation involved a cohort of 15 patients with aMA and 15 patients with iKA, both evaluated two years after their surgeries. All patients underwent robotically assisted procedures following an identical perioperative protocol. A control group consisting of 15 healthy individuals, matched for
age and sex, was also included for comparison. The forward lunge motion was analyzed using a 3D Vicon motion analysis system, focusing on spatiotemporal and kinematic parameters. Data collection was performed by an investigator who was blinded to the group assignments.
Results: The duration of the loading phase of the forward lunge with iKA (39,6%) was close to the healthy controls (43,2%). With aMA, the loading phase was shorter (34,2%). The duration of the push back was longest with aMA (43,0%), when compared to iKA (39,1%) and the healthy controls (33,0%). (Table
1) The range of motion of the knee flexion during forward lunge was 49,8° with iKA, 38,8° with aMA and 68,3° with the healthy controls. Maximal hip flexion angle was 73,6° with iKA, 63,1° with aMA and 76,9° with the healthy controls. (Table 2 and Figure 1&2)
Conclusions: At two years postoperative, performance of the forward lunge with iKA is better compared to aMA. Better preservation of the native anatomy and native joint line obliquity might result in higher performance of loaded activities with demanding motor control such as the forward lunge.
