Unicompartmental knee arthroplasty fails to completely restore normal gait patterns during level walking

Purpose: Gait analysis is a valuable instrument for measuring function objectively after unicompartmental knee arthroplasty (UKA). However, most gait analysis studies have reported conflicting results for functional assessment after UKA. This meta-analysis compared the gait patterns of UKA patients and healthy controls during level walking. Methods: Studies were included in the meta-analysis if they recorded vertical ground reaction force (GRF), flexion at initial contact, flexion at loading response, extension at mid-stance, flexion at swing, walking speed, cadence, and stride length in UKA patients or healthy controls. Results: Seven studies met the criteria for inclusion in the meta-analysis. The UKA patients and healthy controls were similar in terms of vertical GRF (95% CI − 0.54 to 0.23; ns), flexion at initial contact (95% CI − 0.47 to 4.96; ns), flexion at loading response (95% CI − 1.29 to 3.69; ns), and flexion at swing (95% CI − 8.85 to 0.40; ns). In contrast, extension at mid-stance (95% CI 0.53 to 4.88; P = 0.01), walking speed (95% CI − 2.13 to − 0.15; P = 0.02), cadence (95% CI − 1.02 to − 0.25; P = 0.001), and stride length (95% CI − 2.02 to − 0.22; P = 0.01) differed significantly between groups. Subgroup analyses revealed that the pooled data were similar between groups: 1st maximum (heel strike), − 0.43 BW (ns); 1st minimum (mid-stance), 0.61 BW (ns); and 2nd maximum (toe off), − 0.46 BW (ns). Conclusions: There were no significant differences in vertical GRF or overall kinematics in the sagittal plane between UKA patients and healthy controls during level walking. However, the UKA group had a significantly slower walking speed and cadence and a shorter stride length than healthy controls. The current findings suggest that, clinically, UKA fails to completely restore normal gait patterns. Level of evidence: Level II, therapeutic study.