RESUMO
BACKGROUND: Unicompartmental knee arthroplasty (UKA) has been shown to demonstrate some satisfactory short-term outcomes. However, to our knowledge, there have been no reports on midterm or long-term knee extensor strength and leg extensor power post-UKA. AIMS: Therefore, the purposes of this study were: (1) to assess the isokinetic knee extensor strength, leg extensor power and stair performance of elderly participants at 5 years UKA post-operation; (2) to compare the differences in knee extensor strength and leg extensor power between the UKA and contralateral healthy limbs. METHODS: Nineteen elderly participants (75 ± 5 years) who had a medial or a lateral compartment UKA at 5 years post-operation were recruited. The isokinetic knee extensor strength and leg extensor power were measured. The stair performance was tested on a 4-step stair, and ascent and descent velocities were calculated. The pain level was assessed. RESULTS: The UKA limbs' knee extensor strength and leg extensor power were 1.01 ± 0.39 Nm/kg and 0.98 ± 0.27 W/kg, respectively. The stair ascent and descent velocities were 0.37 ± 0.07 and 0.38 ± 0.11 m/s, respectively. In addition, the UKA limbs exhibited comparable knee strength and leg power relative to the contralateral limbs. DISCUSSION: In general, the knee extensor strength and leg extensor power exhibited by the UKA limbs at 5 years post-operation may be typical in comparison with the normative data. CONCLUSIONS: We suggest that UKA is a satisfactory treatment in regard to the recovery of knee strength, leg power and ability to climb up and down stairs.