BACKGROUNDOsteoarthritis often affects the joint bilaterally, and the single-stage (SS) unicompartmental knee arthroplasty (UKA) is advantageous in terms of a single anesthesia administration, a short hospital stay, lower medical costs, and enhanced patient convenience. However, the complication risk of SS UKA continues to be debated. The aim of this article was to evaluate the clinical effectiveness, complications, and functional recovery of SS and two-stage (TS) UKA.

METHODSFrom January 2008 to December 2013, we compared a series of 36 SS UKA with 45 TS UKA for osteoarthritis. The mean age was 65.4 years (range: 55-75 years). The mean body mass index was 25.2 kg/m 2 (range: 22-29 kg/m 2 ). The pre- and post-operative Oxford Knee Scores (OKSs), complications, operative times, tourniquet times, the amount of drainage, and hemoglobin (Hb) were evaluated. The Chi-square test, Fisher's exact test, and paired and grouped t-tests were used in this study.

RESULTSThe mean follow-up was 50 months. No complications of death, fat embolism, deep vein thrombosis, and prosthetic infection were reported. Patients who underwent SS UKA had a shorter cumulative anesthesia time (113.5 vs. 133.0 min, P < 0.01). There were no significant variations between the values of the mean tourniquet time, the amount of drainage, pre- and post-operative Hb in the different groups. No patient required a blood transfusion. No statistical differences were found in the complications between two groups (P > 0.05). At the final follow-up, the mean OKS improved from 39.48 ± 5.69 to 18.83 ± 3.82 (P < 0.01), with no statistical differences between the two groups (P > 0.05). Patients who underwent SS UKA had a faster recovery.

CONCLUSIONSThe single-staged UKA offers the benefits of a single anesthesia administration, reduced total anesthetic time, decreased overall rehabilitation time, and absence of an increase in perioperative mortality or complications compared with the TS bilateral UKA.