(See: Radiographic Features of DDH)
Discussion
- CE angle provides useful information after the age of 5 years (may be used in adults);
- angle formed by a line drawn from the center of the femoral head to the outer edge of the acetabular roof, and a verticle line drawn through the center of the femoral head;
- angle greater than 25 deg are considered normal;
- less than 20 deg indicates severe dysplasia;
- Wiberg examined 44 patients with CE angles less than 20 deg (unselected group) that had no radiographic evidence of DHD;
- in 17 patients (ages 13 to 60 yrs) DJD had developed over a period of 4-28 yrs;
- DJD in the 4th decade had an average CE of 2 deg;
- DJD in the 5th decade had an average CE of 5 deg;
- DJD in the 6th decade had an average CE of 10 deg;
- DJD in the 7th decade had an average CE of 12 deg;
- key point of his study was that patients with subluxation were not separated from patients who only had dysplasia;
- review of these hips showed that most had subluxation;
Cooperman, et al (1983) »
- followed 20 adult patients (32 hips) for avg 22 years.
- 15 women and 5 men.
- all patients had CE angle of less than 20 deg, all had intact Shenton's line, and none had evidence of DJD;
- average initial age was 43 years (27-57 yrs);
- average follow up age was 65 years;
- measurement variables included:
- CE angle
- acetabular angle of Sharp
- percentage of femoral head coverage
- acetabular depth
- inclination of lateral lip of acetabulum.
- none of these variables was predictive for DJD.
- most patients developed DJD but a linear relationship between DJD and CE (or other variables) could not be developed.
- males tended to remain free of DJD longer than females.
- 9 hips remained free of DJD in the 6th decade.
- 6 of these were male.
- 7 patients developed severe DJD (during 4th, 5th, 6th, 7th and 8th decades).
- 4th and 5th decade: 4 hips w/ av CE of 6 deg;
- 6th decade: 3 hips w/ av CE of 6 deg;
- 7th decade: 7 hips w/ av CE of 9 deg;
- 8th decade: 7 hips w/ av CE of 4 deg
- Acetabular Dyplasia in the Adult.
- Studies on Dysplastic Acetabula and Congenital Subluxation of the Hip Joint. Wiberg G. Acta Chir Scand. 1939;(83) Suppl 58:7.