Hip Morphology in Early-stage LCPD: Is There an Argument for Anatomic-specific Containment?

Abstract

Background: Early containment surgery has become increasingly popular in Legg-Calvé-Perthes Disease (LCPD), especially for older children. These procedures treat the proximal femur, the acetabulum, or both, and most surgeons endorse the same surgical option regardless of an individual patient's anatomy. This "one-surgery-fits-all" approach fails to consider potential variations in baseline anatomy that may make one option more sensible than another. We sought to describe hip morphology in a large series of children with newly diagnosed LCPD, hypothesizing that variation in anatomy may support the concept of anatomic-specific containment. Methods: A retrospective review of a prospectively collected multicenter database was conducted for patients aged 6 to 11 at diagnosis. To assess anatomy before significant morphologic changes secondary to the disease itself, only patients in Wal-denström stages IA/IB were included. Standard hip radiographic measurements including acetabular index, lateral center-edge angle, proximal femoral neck-shaft angle (NSA), articulotrochanteric quartiles, and extrusion index (EI) were made on printed anteroposterior pelvis radiographs. Age-specific percentiles were calculated for these measures using published norms. Significant outliers ( ≤ 10th/ ≥ 90th percentile) were reported where applicable. Results: A total of 168 patients with mean age at diagnosis of 8.0 ± 1.3 years met inclusion criteria (81.5% male). Mean acetabular index for the entire cohort was 16.8 ± 4.1 degrees; 58 hips (34.5%) were significantly dysplastic compared with normative data. Mean lateral center-edge angle was 15.9 ± 5.2 degrees at diagnosis; 110 (65.5%) were ≤ 10th percentile indicating dysplasia (by this metric). Mean NSA overall was 136.5 ± 7.0 degrees. Fifty-one (30.4%) and 20 (11.9%) hips were significantly varus ( ≤ 10th percentile) or valgus ( ≥ 90th percentile), respectively. Thirty-five hips (20.8%) were the third articulotrochanteric quartiles or higher suggesting a higher-riding trochanter at baseline. Mean EI was 15.5% ± 9.0%, while 63 patients (37.5%) had an EI ≥ 20%. Conclusions: The present study finds significant variation in baseline anatomy in children with early-stage LCPD, including a high prevalence of coexisting acetabular dysplasia as well as high/low NSAs. These variations suggest that the "one-surgeryfits-all" approach may lack specificity for a particular patient; a potentially wiser option may be an anatomic-specific containment operation (eg, acetabular-sided osteotomy for coexisting dysplasia, varus femoral osteotomy for valgus NSA). Level of Evidence: Level IV.

Predictors of Persistent Limp Following Proximal Femoral Varus Osteotomy for Perthes Disease

“…All radiographic measurements obtained at the initial presentation, 3-month, and 2-year postop visits were performed by 1 of 2 authors, experienced in making these measurements in clinical practice as well as in previous published literature. 11 Previous studies have demonstrated excellent inter-rater reliability for all included radiographic metrics: Waldenström classification (κ: 0.76 to 0.82), NSA (ICC: 0.58 to 0.89), AI (ICC: 0.42 to 0.95), and LCEA (ICC: 0.64 to 0.97). [12][13][14] As such, reliability was not assessed in this study.…”

“…AI was measured as the angle between the line drawn through the superior aspect of the triradiate cartilage bilaterally and a line drawn superolateral triradiate cartilage to the lateral sourcil (weight-bearing aspect of the acetabulum), while LCEA was measured as the angle between the line perpendicular to the line connecting the center of both femoral heads and the line drawn from the center of the femoral head to the lateral most portion of the lateral sourcil. All radiographic measurements obtained at the initial presentation, 3-month, and 2-year postop visits were performed by 1 of 2 authors, experienced in making these measurements in clinical practice as well as in previous published literature 11 . Previous studies have demonstrated excellent inter-rater reliability for all included radiographic metrics: Waldenström classification (κ: 0.76 to 0.82), NSA (ICC: 0.58 to 0.89), AI (ICC: 0.42 to 0.95), and LCEA (ICC: 0.64 to 0.97) 12–14 .…”

What’s New in Pediatric Orthopaedics

“…Legg-Calvé-Perthes Disease Selberg et al hypothesized that variable anatomy supports the concept of anatomically specific containment in Legg-Calvé-Perthes disease. Of 168 patients, 35% were substantially dysplastic, 30% were in varus, and 12% were in valgus, suggesting that the one-surgery-fits-all approach may lack specificity for an individual patient 69 .…”

Anatomic Specific Containment in LCPD

“…We recently read the article by the International Perthes Study Group1 with great enthusiasm as they are attempting to find answers a complex problem. We have a few suggestions for consideration that we believe are relevant to the study.…”