Clinical Efficiency of Fixed-Bearing Unicompartmental Knee Arthroplasty Versus Total Knee Arthroplasty For Lateral Compartment Knee Osteoarthritis and the Effect on Recovery of Motor Function.

Objective: To evaluate the clinical efficiency of fixed-bearing unicompartmental knee arthroplasty (UKA) versus total knee arthroplasty (TKA) for lateral compartment knee osteoarthritis and the effect on the recovery of motor function. Methods: A total of 54 patients who underwent surgery for lateral compartment knee osteoarthritis and satisfied the inclusion criteria from September 2018 to February 2021 at our hospital were recruited and assigned to receive either UKA (UKA group, n=30) or TKA (TKA group, n=24) via random number table method. Among them, the randomization was carried out using an online web-based randomization tool (freely available at http://www.randomizer.org/). Inclusion criteria: 1) patients with lateral compartment knee osteoarthritis diagnosed by clinically relevant tests; 2) patients with structural and functional integrity of the knee ligaments; 3) all with a single knee lesion. Outcome measures included operative time, the reduction ratio of Hb 1d postoperatively, visual analog scale (VAS) score 7d postoperatively, length of hospital stay, postoperative Keen society score (KSS), Oxford knee score (OKS), range of motion (ROM), forgotten joint score (FJS), motor function recovery, and adverse events. Results: All patients were followed up postoperatively for 12-33 (21.71±7.45) months. Patients in the UKA group showed significantly shorter operative indices, a lower reduction ratio of Hb 1d postoperatively, and VAS scores of 7d postoperatively (P < .05). At 1 month and 6 months postoperatively, UKA resulted in significantly better KSS scores, OKS scores, ROM, and motor function recovery versus TKA (P < .05), while the difference of the above indices did not come up to the statistical standard at 1 year postoperatively (P < .05). At 1 year postoperatively, patients receiving UKA were associated with significantly higher FJS scores versus those given TKA. No documented thrombosis, knee, or prosthesis-related adverse events were observed during hospitalization and follow-up. Conclusion: In comparison to TKA, UKA resulted in smaller surgical incisions, improved postoperative healing, and greater restoration of knee function. Both arthroplasties are successful in alleviating pain and increasing knee function, although they are less effective in recovering patients' motor capabilities.