Table 2.
Cohort Studies (and 1 Finite-Element Study)a
| Authors, Year | Study Design | Cohort Characteristics | Imaging Modality Used? | Symptoms, Intra-Articular Pathology, OA, THR? | Methodology of Determining Threshold Value | Suggested Threshold Value | Confounders | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| No. of Cases (Hips) | Mean Age (Measure of Variation) | Sex (%, Male/Female) | (A)symptomatic | Type | Plane | ||||||
| Agricola, 20145 | Prospective cohort | 1457 (2879) | CHECK: mean 55.9 (range, 45-65) Chingford: mean 54.2 (range, 44-67) | CHECK: 20/80 Chingford: 0/100 |
Both | Radiograph | AP/coronal | Pathological cam: end-stage OA within 5-19 years (n = 105) versus no end-stage OA (n = 2774) | Cam morphology: based on bimodal alpha angle distribution, pathological cam morphology: ROC | cam: 60° pathological cam: 78° |
Separate male and female, uni/bilateral, no correction for age |
| Bouma, 20149 | Cross-sectional cohort | 83 (155) | N/A | NFS | Asymptomatic | Radiograph | Cross-table lateral | 95% reference interval | 66° (anatomic method) 58° (3-point method) |
No significant difference in alpha angle in male/female | |
| Fischer, 201812 | Cross-sectional cohort | 3226 (NFS) | 53 ± 14 (range, 21-90) | 49/51 | NFS | MRI (whole body) | AP/coronal | 95% reference interval | 71° | Significant association between age, weight, waist, BMI, height, and alpha angle | |
| Fraitzl, 201313 | Retrospective cohort | 339 (339) | Male: 47 ± 17, female: 55 ± 19 | 50/50 | NFS | Radiograph | AP/coronal and FLL | 95% reference interval | Male (AP/FLL): 70°/70° Female (AP/FLL): 61°/66° |
No correlation between age and alpha angle | |
| Golfam, 201714 | Cross-sectional cohort | 197 (394) | 29.4 (range, 21.4-50.6) | 44/56 | Asymptomatic | MRI | Oblique axial, radial, 1:30-o’clock | 95% reference interval | Axial: 63° Radial: 66° |
Insignificant relation between age and alpha angle, significant relation between sex and alpha angle | |
| Gosvig, 200715 | Cross-sectional cohort | 2803 (NFS) | NFS | 38/62 | NFS | Radiograph | AP/coronal | cam morphology: mean ± 1SD Pathological cam morphology: mean ± 2SD |
Male: 69° (borderline), 83° (pathological) Female: 51° (borderline), 57° (pathological) |
Specified for sex | |
| Laborie, 201425 | Cross-sectional cohort | 2005 (FLL: 3996, AP: 4004) | 18.6 (95% CI, 17.2-20.1) | 42/58 | NFS | Radiograph | AP/coronal (weightbearing) and FLL | 97.5% percentile | Male (AP/FLL): 93°/68° Female (AP/FLL): 94°/56° | Specified for sex and side | |
| Lepage-Saucier, 201426 | Cross-sectional cohort | 94 (188) | 49 ± 16.6 | 52/48 | Asymptomatic | CT | Oblique axial (90°) and double oblique (45°) | 95% reference interval | Male (45°/90°): 93°/68° Female (45°/90°): 84°/69° |
Specified for sex and side | |
| Liu, 201728 | Experimental finite-element study | 1 (1) multiple modeled hips | 35 | 0/100 | NFS | CT | AP/coronal | Peak acetabulum pressure: 60° = 6.295, 70° = 7.291, 80° = 10.620, 90° = 11.460 |
Peak pressure forces between various threshold values and motions | 80° | N/A |
| Mascarenhas, 201832 | Cross-sectional cohort | 590 (1111) | 33 ± 8 | 46/54 | Asymptomatic | CT | Pelvis: 9 positions around head-neck | 95% reference interval | 65°-70° for 12.00/3.00-o’clock 60° for 1- to 1.30-o’clock | Age, side, limb dominance, and sex | |
| Pollard, 201040 | Cross-sectional cohort | 83 (166) | 46 (range, 22-69) | 47/53 | Asymptomatic | Radiograph | Cross-table lateral | 95% reference interval | 62° | No significant difference between sex | |
aAP, anteroposterior; BMI, body mass index; CHECK, Cohort Hip & Cohort Knee; CT, computed tomography; FLL, frog-leg lateral; MRI, magnetic resonance imaging; N/A, not available; NFS, not further specified; OA, osteoarthritis; ROC, receiver operating characteristic; THR, total hip replacement.