Table III.
Definition of CAM impingement and arthritis across continents
| North America | South America | Europe | Asia | Australia | |
|---|---|---|---|---|---|
| Definition of cam impingement | |||||
| Number of studies reporting (subjects) (% of studies reporting a definition) | 14 (949) (18%) | 0 | 7 (337) (9%) | 1 (21) (9%) | 1 (34) (20%) |
| Alpha angle > 45° (oblique) | 1 (36) | 0 | 0 | 0 | |
| Alpha angle > 50° (Dunn 90°) | 3 (67) | 0 | 0 | 0 | |
| Alpha angle > 50° (Cross-table lateral) | 1 (60) | 0 | 0 | 0 | |
| Alpha angle > 50° (Cross-table lateral, frog-leg lateral) | 0 | 0 | 1 (21) | 0 | |
| Alpha angle > 50° (Cross-table lateral, Dunn 45°) | 0 | 1 (110) | 0 | 0 | |
| Alpha angle > 50° (AP, cross-table lateral) | 1 (185) | 0 | 0 | 0 | |
| Alpha angle > 50° (AP, cross-table lateral, Dunn 45°) | 1 (210) | 0 | 0 | 0 | |
| Alpha angle > 55° (MRI, axial oblique) | 0 | 2 (42) | 0 | 0 | |
| Alpha angle > 55° | 1 (9) | 0 | 0 | 0 | |
| Alpha angle > 55° (cross-table lateral) | 2 (126) | 1 (96) | 0 | 0 | |
| Alpha angle > 55° (MRI, axial oblique) | 1 (50) | 0 | 0 | 0 | |
| Alpha angle > 55° (MRI, radial) | 0 | 1 (38) | 0 | 0 | |
| Alpha angle > 55° (Cross-table lateral, or CT scan) | 0 | 0 | 0 | 1 (34) | |
| Alpha angle > 60° (AP, frog-leg lateral, or Dunn 90°) | 1 (58) | 0 | 0 | 0 | |
| Qualitative (Femoral head asphericity) | 2 (148) | 1 (40) | 0 | 0 | |
| Qualitative (Pistol-grip deformity) | 0 | 1 (11) | 0 | 0 | |
| Mean alpha angle (degrees) | 63.8 ± 8.70 | nr | 67.6 ± 9.39 | 65.7 ± 8.5 | nr |
| Number of studies reported (subjects) | 13 (2666) | 5 (256) | 1 (21) | ||
| Proportion of studies reporting (subjects) | 17% (45%) | 14% (7.1%) | 9.1% (11%) | ||
| Definition of arthritis | |||||
| Number of studies defining hip arthritis (number of hips) | 46 (3099) (59%) | 0 | 24 (2203) (65%) | 7 (180) (64%) | 2 (630) (40%) |
| Via Tonnis grade | 16 (1632) | 12 (435) | 4 (66) | 0 | |
| ≥2 | 15 (1526) | 12 (435) | 4 (66) | ||
| ≥1 | 1 (106) | 0 | 0 | 0 | |
| Via joint space narrowing | 5 (345) | 0 | 1 (21) | ||
| <3 mm | 2 (172) | 0 | 0 | ||
| <2 mm | 2 (172) | 0 | 0 | 1 (560) | |
| ‘Joint space narrowing’ | 1 (1) | 0 | 1 (21) | 0 | |
| Via Outerbridge classification | 3 (291) | 1 (94) | 0 | 1 (70) | |
| Via ‘arthritis’ or ‘osteoarthritis’ | 18 (776) | 9 (1513) | 2 (93) | 0 | |
| Via ‘degenerative changes’ | 3 (19) | 0 | 0 | 0 | |
| Via ‘cartilage delamination’ | 1 (36) | 0 | 0 | ||
| Via Kellgren–Lawrence grade | 0 | 1 (11) | 0 | ||
| Number of hips with arthritis (%) | 312 (10.1%) | nr | 387 (17.6%) | 16 (8.9%) | 137 (21.7%) |
CT, computed tomography; nr, not recorded.