Background:The potential advantages of patient-specific (PS) compared with off-the-shelf (OTS) unicompartmental knee arthroplasty (UKA) in terms of knee function remain unclear.Therefore, the aim of this study was to determine whether PS-UKA implant leads to superior improvement in terms of knee joint function compared with an OTS-UKA while performing a deep squat.Methods: Twenty-two patients and 22 healthy individuals, matched for age and height, were recruited.Eight patients were operated with PS-UKA, and 14 patients with OTS-UKA.All patients were evaluated at a minimum follow up of 3 years post-surgery.Participants were instructed to squat as deeply as possible.Sagittal, frontal and transverse kinematics and kinetics were calculated for hip, knee and ankle joints.Co-contraction index was calculated for knee flexor and extensor muscles.Statistical Parametric Mapping was used to compare dependant variables.Results: PS-UKA and OTS-UKA showed no significant differences in spatiotemporal, kinematic, or kinetic outcomes.Compared with controls, OTS-UKA displayed reduced knee flexion, lower hip and knee sagittal range of motion, decreased hip contribution, and increased ankle contribution to total support moment. Conclusion:The personalization of the implant did not demonstrate superior knee function compared with off-the-shelf UKA during squatting.The decrease in maximum knee flexion compared with the control group may be associated with fear of movement for both designs.In addition, PS-U KA and OTS-UKA patients adopted an ankle dominant strategy during squatting compared with the control group.Further analyses are required to validate these findings in other, more challenging functional tasks such as sit-to-stand and stairs negotiation.
M’barki et al. (Sat,) studied this question.