Figure 1

Figure 2

Figure 3

Correlation between the HEAD-US and IPSG MRI scores
| Elbows | Knees | Ankles | All joints | |
|---|---|---|---|---|
| Overall score (r) | 0.949 | 0.941 | 0.838 | 0.921 |
| Detailed scores: | ||||
| Synovial hypertrophy (r) | 0.840 | 0.710 | 0.561 | |
| Cartilage degradation (r) | 0.734 | 0.812 | 0.537 | |
| Bone changes (r) | 0.883 | 0.741 | 0.725 |
Baseline characteristics of the study population
| Age: median; range (years) | 33; 16–49 | |||||
| Age of start of prophylaxis: mean (years) | 17.4 | |||||
| age group: 0–9 (patient count) | 7 | |||||
| age group: 10–19 (patient count) | 14 | |||||
| age group: 20+ (patient count) | 9 | |||||
| Duration of prophylaxis: mean (years) | 15.4 | |||||
| Ankles | Knees | Elbows | ||||
| Right | Left | Right | Left | Right | Left | |
| No. of joints | 30 | 29 | 25 | 28 | 28 | 28 |
| No. of lifetime joint bleeds: | 5 | 5 | 12 | 15 | 14 | 13 |
| 0–5 (joint count) | 12 | 11 | 7 | 10 | 4 | 2 |
| 6–20 (joint count) | ||||||
| > 20 (joint count) | 13 | 12 | 5 | 3 | 9 | 12 |
| Unknown (joint count) | 0 | 1 | 1 | 0 | 1 | 1 |
| HJHS 2.1 score: mean; max* | 3.3; 12 | 2.6; 11 | 1.4; 7 | 1.2; 8 | 1.9; 9 | 1.9; 8 |