Table 1 Characteristics of the patients
| Â | Pre-surgery | Six-months follow-up | Two-years follow-up |
|---|---|---|---|
N | 298 | 176 | 111 |
Age*, years | Â | Â | Â |
   Mean (SD) | 66.8(7.6) | 66.9(7.8) | 66.3(7.9) |
Female, n (%) | 226(80.4) | 137(79.7) | 84(77.8) |
Ethnicity, n (%)†|  |  |  |
   Chinese | 257(92.1) | 156(91.2) | 97(89.8) |
   Others | 22(7.9) | 15(8.7) | 11(10.19) |
Right knee, n (%) | 161(54.0) | 99(56.3) | 64(57.7) |
Years with OA, mean(SD) | 7.8(3.8) | 7.7(3.5) | 7.7(3.8) |
BMI (kg/m2), mean(SD) | 27.9(4.3) | 28.1(4.2) | 28.2(4.1) |
   < 25, n (%) | 101(34.5) | 57(32.8) | 33(30.3) |
   25-29.9, n (%) | 116(39.6) | 72(41.4) | 45(41.3) |
   > 30, n (%) | 76(25.9) | 45(25.9) | 31(28.4) |