Chiari pelvic osteotomy in the management of developmental hip dysplasia: a long term follow-up.
OBJECTIVE
Developmental hip dysplasia in adults causes several anatomical changes which can lead to premature and progressive secondary osteoarthritis. The principle of Chiari osteotomy is the medialisation of the subluxated femoral head. This improves the biomechanics of the hip. The goal of the study was to assess the long term results of Chiari innominate osteotomy.


METHODS
The authors evaluated 130 hips after Chiari ostetomy from 230 patients operated on in the sears 1969-1985 at the Ist Orthopaedic Department of St. Anna University Hospital in Brno, Czech Republic. The mean follow-up was 22.3 years (15-30) and there were 125 women and 5 men. The average age at the time of the procedure was 29 years (15-52).


METHODS
We assessed the Harris hip score, daily activities, the length of the improvement after the procedure and asked the patients if they would undergo again the same procedure. We also assessed the CE angle, the Sharp angle, AHI index, the CCD angle, the Shenton's line, Crowe type of dysplasia, the shape of the femoral head and Kellgren-Lawrence grades of the osteoarthritis. There were 5 types of hip dysplasia in the study: coxa valga subluxans, coxa valga luxans, coxa plana brevis, coxa magna and severe deformity of the femoral head. There were 26 cases of hip dysplasia alone, 87 cases of hip dysplasia with a subluxation of the femoral head and 13 cases of dysplasia with a false acetabulum. We searched for the factors influencing the end results. We measured the medial shift of the distal pelvic fragment and the level of the osteotomy.


RESULTS
The mean nmedial shift of the distal fragment was 22 mm e.g. 48.6%. There was a correct level of the osteotomy in 113 patients. Radiological features improved: the CE angle (-12 degrees to +37.2 degrees), the Sharp angle (48 degrees to 41 degrees), AHI index (51 to 96.3%). The Harris hip score improved from 42 points to 67.5 points an average. 65 patients have been satisfied with the procedure, 49 were partialy satisfied and 16 were not satisfied. There were 80 patients without any other procedure (the first group) and there were 50 patients with the conversion to total hip replacement at the time of the latest follow-up (the second group). The mean age at the time of the operation was 24.2 years in the first group and 33.7 years in the second group. 62 patients in the first group had no osteoarthritis or grade 1 osteoarthritis at the time of the operation. 43 patients in the second group had grade 2 or 3 osteoarthritis at the time of the operation. The favourable results of the operation lasted 17.6 years in the first group and 11.1 years in the second group. The time between Chiari osteotomy and the conversion to total hip replacement was 12.2 years in the second group.


CONCLUSIONS
The favourable factors are the age up to 30 years, no osteoarthritis or the grade 1 of osteoarthritis, coxa valga subluxans of Crowe type I and type II of hip dysplasia with a normal Shenton line, the spherical and ovoid shape of the femoral head, the correct level of the osteotomy and full coverage of the femoral head (medial shift 40%). The unfavourable factors for long term results were older age (over 35 years) of the patient at the time of the operation, grade 2 and 3 of osteoarthritis, severe deformity of the femoral head, Crowe type III of hip dysplasia with broken Shenton's line more than 20 mm, an angular shape of the femoral head, a CE angle bellow -15 degrees, a high CCD angle (near to 180 degrees) and incorrect procedure technique.


CONCLUSIONS
The study approved a favourable effect of Chiari pelvic osteotomy in patients with residual developmental hip dysplasia. The authors evaluated 130 patients operated on in the years 1969-1985 with a mean follow-up 22.3 years. In the first group (80 patients) a favourable result lasted an average of 17.6 years (3-30). 37 patients are still painfree, 35 patients have conservative treatment for osteoarthritis, 8 patients are planning a conversion to total hip replacement. Radiological signs have improved substantialy. Harris hip score has improved from 42 points to 67.5 points on average. In the second group (50 patients) a favourable result lasted for average 11.1 years (0-29). All of them had a conversion to total hip replacement at the average of 12.2 years. Chiari osteotomy gives the patients with residual developmental hip dysplasia and a correct indication favourable long-term results. It diminishes pain, prevents further subluxation and reduces the development of secondary osteoarthritis of the hip joint. (Tab. 6, Ref. 23.).
Rozkydal
Z
Z
Ist Orthopaedic Department, St. Anna University Hospital, Brno, Czech Republic. zrozkydal@med.muni.cz
Kovanda
M
M
D000293:Adolescent; D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D006618:Hip Dislocation, Congenital / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010027:Osteotomy; D010384:Pelvic Bones / Q000601:surgery*