[Short-term effectiveness of medial unicompartmental knee arthroplasty in patients younger than 60 years of age].

Objective: To compare the short-term effectiveness of medial unicompartmental knee arthroplasty (UKA) between patients younger or older than 60 years of age, and to investigate the impact of age on the effectiveness.

Methods: The clinical data of 182 patients (182 knees) who underwent medial UKA between July 2016 and June 2018 were retrospectively analyzed, of which 72 patients were less than 60 years old (group A) and 110 patients were more than 60 years old (group B). There was a significant difference in age between groups (=-20.198, <0.001). No significant difference was found in gender, body mass index, surgical sides, Kellgren-Lawrence grading, disease duration, and preoperative Western Ontario and McMaster University Osteoarthritis Index (WOMAC) score between groups (>0.05). The postoperative hospital stay and complications were recorded, and the WOMAC score, satisfaction score, and prosthesis revision were compared between groups.

Results: The length of postoperative hospital stay was (4.50±1.09) days in group A, and (4.46±1.29) days in group B, with no significant difference between groups (=0.198, =0.844). All incisions healed by first intention. The incidences of early postoperative complications in groups A and B were 5.6% and 3.6%, respectively, and the difference was not significant (=0.061, =0.804). All patients were followed up. The follow-up time were 28-50 months (mean, 36 months) in group A and 28-50 months (mean, 35 months) in group B. At last follow-up, the WOMAC scores of both groups significantly improved when compared with those before operation (<0.05), and there was no significant difference between groups (>0.05) in the difference before and after operation. The satisfaction scores were 6.6±1.7 in group A and 6.9±1.6 in group B, with no significant difference between groups (=-1.326, =0.186). There was no revision surgery in both groups during follow-up period.

Conclusion: Age has no significant effect on the prognosis of medial UKA, and patients younger than 60 years of age can also obtain good short-term effectiveness.