|Abstract / Summary
This thesis is based on four clinical studies concerning LCPD and the associated radiographic changes in the hip joint from the time of diagnosis to adulthood. The aims of the thesis were: I. To evaluate whether severity of disease, age at onset, gender and presence of HAR signs were risk factors for poor radiological outcome after non-containment treatment of LCPD patients. IIa. To evaluate whether patients with LCPD were more at risk of having radiographic hip OA than control subjects, and whether hips with Stulberg Classes III/IV/V femoral heads had an increased prevalence of OA compared with hips with Stulberg Classes I/II femoral heads. IIb. To determine whether conservatively treated patients with LCPD had an increased prevalence of THA compared with gender- and age-matched control subjects, and if patients with Stulberg Classes III/IV/V femoral heads had an increased risk of THA compared with patients with Stulberg Classes I/II femoral heads. III. To compare radiographic parameters in the affected and non-affected hip in children suffering from LCPD with those of a control group, and to evaluate whether the radiographic changes were present at the time of diagnosis or developed later. IV. To evaluate the prevalence of HD in adult LCPD patients and describe radiographic parameters of the affected and the non-affected hips in adult LCPD patients compared with those of a control group. Patients included in the current study were referred to The Community of Disabled in Kolding, Denmark from 1941 to 1962. All patients were treated by a Thomas splint regardless of gender, age at onset of the disease, unilateral or bilateral disease, and severity of disease. The splint was used from the time of diagnosis until the reconstitution stage of the disease appeared on the radiographs. At the time of diagnosis, the CE angle and the AA were measured on AP pelvis radiographs. At the fragmentation stage of the disease, radiographs were classified according to the modified Herring lateral pillar classification system into Herring group A, B, B/C and C. Presence of the five HAR signs (lateral calcifications, metaphyseal cysts, a horizontal growth plate, lateral subluxation and Gage’s sign) were noted. At skeletal maturity, AP and frog-leg lateral view were classified according to the revised Stulberg classification system into Stulberg Class I, II, III, IV and V. Radiographs of gender- and age-matched control persons were obtained from Kolding Hospital. At follow-up in 2005-2006, all patients, except for patients who had deceased, emigrated or were lost to follow-up owing to lack of a personal identification number in the civil registration system, were invited to a radiographic examination. Weight-bearing standardised AP pelvic radiographs were obtained. In patients without THA, the JSW, CE angle, AA and FHEI were measured. For the estimation of THA in patients who were deceased or who did not want to participate at follow-up, data from the national Danish Hip Arthroplasty Register and the Registries of the National Board of Health were collected. Radiographs of gender- and age-matched control persons were obtained from the CCHS. Our study found that: I. A higher Herring groups as well as age at onset of disease were significant risk factors for a poor Stulberg outcome. No statistically significant correlation between respectively gender and presence of HAR signs and Stulberg Class was shown. IIa. LCPD patients have an increased risk of hip OA compared with a gender- and age- matched control group. Patients in Stulberg Class III/IV/V have an increased risk of OA compared with patients in Stulberg Class I/II. IIb. The prevalence of THA in LCPD patients is increased compared with gender- and age- matched control persons. The risk of having THA is increased in Stulberg Class III/IV/V hips compared with Stulberg Class I/II hips. III. In the affected hip of LCPD patients the femoral head changes at diagnosis occur in an acetabulum similar to a gender- and age-matched control group evaluated by the CE angle and AA, which secondarily becomes deformed. In the non-affected hip, the radiographic measurements are the same as in the gender- and age-matched control group at the time of diagnosis of the disease. However at skeletal maturity the parameters are significantly different in Stulberg Class III/IV/V compared with the control group. IV. Adult LCPD patients have a significantly increased prevalence of HD in the affected hip regardless of Stulberg Class compared with a control group. In contrast, the prevalence of HD in the non-affected hip is similar to the control group. In the affected hip and in the non-affected hip in Stulberg Class III/IV/V the CE angle is decreased and the AA is increased compared with the control group.