No clinical relevant differences in early clinical outcomes, patient satisfaction and objective gait and posture analysis between a custom versus off-the-shelf total knee arthroplasty: a prospective controlled study

Osteoarthritis is one of the most frequent joint diseases in the world. Therefore, it is critical to develop sufficient therapy strategies to improve a patient's quality of life. The aim of this study was to evaluate the influence of an individualized (custTKA) vs. a conventional (convTKA) total knee arthroplasty (TKA) in regard to gait, posture and clinical outcome. Seventy-three patients (male: n = 32, female: n = 41; age: 66.5 ± 8.64 years; BMI: 32.2 ± 5.68 kg/m²; axis pre-operative: 174 ± 4.65°) were included in this prospective controlled trial study (examinations 1, 2 and 3: preoperative, 3 and 12 months postoperative). Two experienced senior surgeons performed the surgeries. Clinical results were measured using the Forgotten Knee Joint Score (FKJS) and Knee Society Score (KSS). Additionally, gait was measured with inertial sensor based mobile and treadmill based systems, while posture was measured with a posturographic system in order to assess gait patterns and postural stability, regulation and weight distribution. Radiographic evaluation was measured of the hip knee ankle (HKA)) at 3 and 12 months postoperative. There were no clinically significant interaction effects (time x group) for posture (e.g., stability indicator, postural subsystems) or gait (e.g., stride length, walking speed, double support). However, time effects were observed for the somatosensory system (p = 0.005, η_p² = 0.08), medio-lateral weight distribution (p < 0.001, η_p² = 0.31), stride length (p < 0.001, η_p² = 0.21), walking speed (p < 0.001, η_p² = 0.21), cadence (p < 0.001, η_p² = 0.18), stance phase (p < 0.001, η_p² = 0.20) and maximum toe force (p < 0.001, η_p² = 0.24). No significant differences were found for KSS or FJS 3 and 12 months postoperative (custTKA/convTKA: KSS examination 2 179/189, p = 0.153; KSS examination 3 206/198, p = 0.246; FKJS examination 2 41.4/40.7, p = 0.900; FKJS examination 3 54.9/45.8, p = 0.149). Similarly, no significant differences were noted for flexion at 3 (113/119°, p = 0.062) and 12 months postoperative (121/122°, p = 0.615). Radiographic diagnostic (HKA) also displayed no significant-relevant interaction effects. In this prospective controlled study no clinical significant-relevant interaction effects (group x time) were found between both techniques regarding biomechanical and clinical parameters. Therefore, it can be concluded that custTKA provides no substantial clinical benefits compared to convTKA.