ESPE Abstracts

Objectives: Lower limb deformities are a significant burden for patients with rickets and related disorders. However, there is limited structured data on this important symptom in hypophosphatemic and hypocalcemic conditions. This review aims to present the available data and identify gaps in the literature regarding lower limb deformities in patients with hypophosphatemic rickets (HPR) such as XLH and hypocalcemic types of rickets (HCR).

Methods: A thorough literature search was conducted on PubMed using the terms “rickets” and “deformity” combined with the Boolean operator “AND” up to 08/2023. Studies included had to feature pediatric case series specifying the type of rickets and describing lower limb deformities. Exclusion criteria were review articles, book chapters, redundant patient data, and secondary rickets.

Results: Out of 126 studies, 2924 patients with leg deformities associated with rickets were included. Varus deformities were reported in nearly equal numbers among HPR and HCR patients. However, valgus leg deformity and windswept deformities were more common in HCR patients. Pathologic femoral torsion was documented only in HPR (n = 70), along with 85 cases of procurvatum and 6 cases of recurvatum femoral deformities. Seven studies on sagittal tibial deformities showed a higher prevalence in the HPR cohort. Basic laboratory assessments (ALP and Phosphorus or Calcium) were reported in 54.8% of the studies, while only 17.5% assessed and defined at least one radiographic or functional parameter (e.g., gait laboratory data) to quantify deformities. Merely 5.6% (7/126) of the studies included both minimal radiological and basic laboratory assessments, all of these describing deformities in patients with HPR.

Conclusions: The current data on X-linked hypophosphatemia (XLH) and other forms of rickets are limited, making it difficult to draw precise conclusions about deformity variations. Only 5.6% of studies document lower limb deformities using standardized, basic radiological and lab parameters. The available data is heterogeneous and often lacks the minimal standards necessary for sufficient interpretation. Establishing minimal quality criteria for deformity assessment is crucial to address the needs of this vulnerable patient cohort. Deformities associated with rickets require a multidisciplinary approach, highlighting the need for multidisciplinary research efforts.