Clinical and functional outcome of the knee after Unicompartmental Knee Arthroplasty (UKA) and its correlation with lower limb mechanical axis correction.
We have reviewed the outcome of 29 UKA, corresponding to 29 patients, with an average follow-up of 4.5 years (3-6 years). The distribution was, 21 women and 8 men, 11 unicompartmental osteoarthritis, 17 femoral condyle necrosis and 1 tibial plateau necrosis, and 27 medial versus 2 lateral affected compartments. The clinical-functional situation of the knees was assessed through the Knee Society Score (KSS), and the mechanical axis through long standing film. To calculate the statistical non-parametric correlation between the different parameters, Spearman's coefficient was used.
In the last review, the increases in the mean clinical KSS and functional KSS were significantly different, with +31.24 (±15.7) and +43.66 (±18.4) points, respectively. The mean change in the femorotibial angle was 2°±4°. We did not find any correlation with statistical significance between the average increases obtained in KS scores and: the alignment of the knee before and after the surgery; the thickness of the inserted polyethylene; the variation of the posterior tibial inclination; Insall-Salvati's index. There was no statistically significant association between the variation in the total KS score and the type of implant or the surgical technique used.
We did not find any correlation between the clinical results and the radiological measurements in this population.