Table 3.
Factors associated with progression of ultrasound findings between repeat imaging
| Factor | Hips with progression (n=26) | Hips without progression (n=22) | P |
|---|---|---|---|
| Sex | 13 (50%) Female 13 (50%) Male |
13 (59%) Female 9 (41%) Male |
0.735 |
| Age at first scan | Mean, 63.0 years (range, 39.0–82.2 years) |
Mean, 60.5 years (range, 39.0–78.8 years) |
0.433 |
| Primary hip type | 16 (62%) THA 10 (38%) HR |
11 (50%) THA 11 (50%) HR |
0.609 |
| Other hip replacements | 13 (50%) Bilateral 13 (50%) Unilateral |
13 (59%) Bilateral 9 (41%) Unilateral |
0.735 |
| Inclination of acetabular component | Mean, 44.2° (range, 25.3°–61.4°) |
Mean, 45.6 ° (range, 31.5°–66.5°) |
0.585 |
| Time to first scan | Mean, 4.6 years (range, 0.7–11.7 years) |
Mean, 5.5 years (range, 0.5–11.1 years) |
0.252 |
| Time between scans | Mean, 1.2 years (range, 0.2–3.3 years) |
Mean, 0.89 years (range, 0.2–1.7 years) |
0.101 |
| Oxford Hip Score | Median, 43.8% (IQR 26.0–60.4%) OR Median, 27.0/48 (IQR, 19.0/48–35.5/48) |
Median, 43.8% (IQR 17.7–65.6%) OR Median, 27.0/48 (IQR, 16.5/48–39.5/48) |
0.909 |
| Blood cobalt concentration | Median, 7.5µg/l (IQR, 3.0–10.6µg/l) |
Median, 7.6µg/l (IQR, 2.7–11.2 µg/l) |
0.764 |
| Blood chromium concentration | Median, 4.5µg/l (IQR, 2.0–6.3µg/l) |
Median, 4.9µg/l (IQR, 3.1–6.7µg/l) |
0.413 |
| Initial scan volume | Mean, 43.3cm3 (0–316.0cm3) |
Mean, 52.9cm3 (0–588.0cm3) |
0.772 |
| Grade of initial scan | 8 (31%) Grade 1 5 (19%) Grade 2 2 (8%) Grade 3 11 (42%) Grade 4 |
10 (45%) Grade 1 3 (14%) Grade 2 1 (5%) Grade 3 8 (36%) Grade 4 |
0.752 |
THA = total hip arthroplasty; HR = hip resurfacing; IQR = interquartile range