Table 1.
Patients’ background characteristics
| Variable | Frequency |
|---|---|
| Age (y) | 60.4 (8.7) |
| Male/female (patients) | 20/64 |
| Right/left side (knees) | 51/42 |
| Unilateral/bilateral (knees) | 84/9 |
| Body weight (kg) | 65.7 (12.1) |
| BMI (kg/m2) | 26.6 (4.0) |
| Young adult mean (%) of the bone mineral density | 90.8 (15.8) |
| OA gradea (patients) | |
| Grade 0 | 0 knees |
| Grade 1 | 0 knees |
| Grade 2 | 17 knees |
| Grade 3 | 61 knees |
| Grade 4 | 6 knees |
| SONKb (patients) | |
| Stage 1 | 0 knees |
| Stage 2 | 4 knees |
| Stage 3 | 4 knees |
| Stage 4 | 1 knee |
Mean (standard deviation).
OA osteoarthritis, SONK spontaneous osteonecrosis of the knee.
aKellgren-Lawrence grading system
bKoshino’s stage [23]