Background: Lateral growth disturbance of
the capital femoral epiphysis is the most common type of physeal
arrest complicating the treatment of developmental hip dysplasia.
Although this type of physeal damage has been assumed to result
in poor acetabular development, the natural history of dysplastic
hips affected by this pattern of growth disturbance is still unclear.
To investigate this issue, we evaluated acetabular development in
a retrospective study of fifty-eight hips in forty-eight patients
who had lateral physeal arrest after management of developmental
Methods: Of the fifty-eight hips, thirty-six
were reduced closed and twenty-two were reduced open. The average
age of the patients was twenty-two months (range, three to ninety-seven
months) at the time of the reduction and twenty-one years (range,
ten to fifty-five years) at the time of the latest follow-up evaluation.
Hips rated as Severin class I (an excellent result) or II (a good
result) were defined as having a satisfactory result, and those
rated as Severin class III (a fair result) or IV (a poor result) were
considered to have an unsatisfactory result. Specific femoral head
changes were sought in the complete radiographic files on all hips.
Various radiographic parameters of hip integrity, including the
degree of lateral tilt of the capital femoral epiphysis, were measured
over time, and comparisons were made between hips classified as
satisfactory and those classified as unsatisfactory at four time-points:
before the reduction, at two years after the reduction, at six to
eight years of age, and at the time of the final follow-up.
Results: Lateral growth disturbance of the capital
femoral epiphysis was first evident by an average of ten years of
age (range, four to fourteen years of age). There was no consistent
early pattern of changes in the epiphysis, physis, or metaphysis
related to later development of valgus tilt of the epiphysis. Thirty-four
hips (59 percent) were rated as satisfactory and twenty-four were
rated as unsatisfactory at the latest follow-up evaluation. Hips
classified as unsatisfactory exhibited poor acetabular development
by an average age of seven years. The inclination of the epiphyseal
plate became progressively more horizontal or even reversed over time;
however, serial measurements of inclination were not significant
predictors of Severin classification.
Conclusions: Lateral growth disturbance of the
capital femoral epiphysis is not necessarily associated with poor acetabular
development, as when dysplasia does occur it is generally evident
prior to the identification of the physeal arrest. It is important
to monitor acetabular development after reduction rather than search
for radiographic changes of physeal arrest, which are difficult
to detect in young children.