OBJECTIVETo compare the early clinical outcomes of primary total knee arthroplasty in the valgus knee between mobile-bearing prosthesis and fixed-bearing prosthesis.

METHODSFrom January 2011 to December 2013, 17 patients (23 knees) treated by the same surgeon were selected for a retrospective study in the First Hospital of Jilin University, including 2 males and 15 females with a mean age of 61.5 years old (48 to 75 years). The pre-operative diagnosis included osteoarthritis (14 patients, 19 knees) and rheumatoid arthritis (3 patients, 4 knees). The patients with valgus deformity were divided into group A and group B. The patients in group A were treated with the fixed-bearing prosthesis (9 patients, 12 knees), and the patients in group B were treated with the mobile-bearing prosthesis (8 patients, 11 knees). The Knee Society Score (KSS), Hosptial for Special Surgery (HSS), Western Ontario MacMaster (WOMAC), the range of motion (ROM) and femorotibial angle were collected at pre-operation and post-operation follow-up for statistical analysis.

RESULTSAll the patients were followed up, and the duration ranged from 6 to 36 months (mean 25 months). The valgus deformity was corrected in all patients, and there were significant differences for all patients between pre-operation and post-operation at the latest follow-up with regard to the KSS knee score, function score, HSS score, WOMAC score, ROM and femorotibial angle (P<0.01). There were no significant differences in KSS knee score, function score, HSS score, WOMAC score, improvement in ROM and femorotibial angle between two groups at the latest follow-up. However there were significant differences in ROM (P<0.05) between fixed-bearing group (101.8±8.8)° and mobile-bearing group (108.4±7.2)° at the latest follow-up. No case with spin-out of mobile bearing was observed. There were no complications in any patient, such as infection, common peroneal nerve injury, dislocation and instability. The X-ary imaging showed no osteolysis or implant loosening.

CONCLUSIONThe early clinical outcomes of primary total knee arthroplasty by using mobile-bearing prosthesis and fixed-bearing prosthesis are satisfactory for the treatment of the valgus knee, and the short term clinical outcomes of mobile-bearing TKA and fixed-bearing TKA are similar.