Catterall grouping of Perthes' disease. An assessment of observer error and prognosis using the Catterall classification

Abstract

A study was undertaken to assess the degree of inter-observer error when a panel of observers classified the radiographs of patients with early Perthes' disease, using Catterall grouping and "at risk" signs. The anteroposterior and lateral radiographs, taken within three months of diagnosis of Perthes' disease, were available for 69 hips and were shown in turn to 10 observers. The radiological end-results were assessed at least four years from diagnosis. The results showed a poor ability of the observers to delineate Groups 1, 2 and 3, with a more satisfactory performance in Group 4 and when Groups 2 and 3 were combined. Interpretation of "at risk" signs was unsatisfactory except when there was an increase in medial joint space greater than two millimetres. The end-results correlated well with early Catterall grouping and "at risk" signs when these were correctly interpreted.

Prognosis in Perthes' disease after noncontainment treatment

“…The controversial results with Catterall's groups and head-at-risk signs as indicators of long-term prognosis may partly be due to difficulties in delineating the radiographic hallmarks of these changes (Hardcastle et al 1980). Aged 10, the bicompartmentalization has normalized after treatment.…”

Do Femoral or Salter Innominate Osteotomies Improve Femoral Head Sphericity in Legg-Calvé-Perthes Disease? A Meta-analysis

“…They found that if surgery was performed during or after late fragmentation, the OR of femoral head asphericity was 16.58 (p \ 0.01; 95% CI, 2.6-103.13) as compared with surgery performed during or before early fragmentation. These and multiple other studies [2,6,14,16,20,21,23,26,27,30,31,33,35,47] have found better femoral head sphericity when surgery has been performed at an earlier stage. Despite our findings, we also believe stage at treatment is crucial in terms of altering the natural history of the disease.…”

“…More recently it has been suggested that age along with amount of head collapse as judged by the modified lateral pillar classification are better prognostic indicators of head sphericity at skeletal maturity [18]. In addition, many authors suggest the stage at which surgery is undertaken directly affects femoral head sphericity [2,6,14,16,20,21,23,26,27,31,33,35,37,47]. Although multiple treatment modalities are available, their effects on the natural history of the disease are unclear.…”

Can Residual Leg Shortening Be Predicted in Patients With Legg-Calvé-Perthes’ Disease?

“…Second, the severity of disease was classified using a simplified system. Although the Catterall classification system reportedly has poor interobserver reliability [8,15], the modified two-group Catterall classification, with 50% involvement of the femoral head as the dividing line, may be more reliable [38]. Because lateral pillar classifications of femoral head involvement of B/C border and C have been considered to carry less favorable prognoses, we also used a modified two-group lateral pillar classification [30].…”