Is the “Too Long Anterior Process” of the Calcaneus Really Too long?
A Retrospective Study Defining the Normal Distance Between the Anterior Process of the Calcaneus and the Navicular Bone in Asymptomatic Feet
2Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
3Occupational Medicine Department, Maccabi Healthcare Services, Rishon Letzion, Israel
Objective:
The purpose of this study is to define the normal anatomy and distance between the anterior calcaneal process and the navicular bone.
Methods:
A retrospective population-based study was performed on contralateral uninjured feet CT studies of patients 9-18 years of age examined at the Shamir medical center (SMC) due to foot and ankle trauma between 2012 - 2020. The antereo calcaneal navicular distance (ACND) between the anterior process of the calcaneus and the navicular bone was measured on both axial and sagittal CT images by 2 orthopaedic surgeons in randomized order. Intra and inter observer reliability was calculated.
Results:
The study included 104 patients, 62 males and 39 females. Median age was 13.5 years. The ACND on axial view was 3.5 ± 2.6 mm (mean ± SD) and on sagittal view 3.5 ± 2.5mm. Intra-reader reliability ICC’s were 0.98-0.99 and 0.79-0.89 for readers 1 and 2. Inter-reader reliability ICC’s were 0.93-0.82 (axial view) and 0.97-0.87 (sagittal view). Young age and female gender were significantly associated with decreased ACND.
Conclusion:
The ACND on both axial and sagittal views in asymptomatic pediatric feet is considerably less than distance of 5-10mm cited in the literature (p<0.001).