Weightbearing CT in normal hindfoot alignment - Presence of a constitutional valgus?

A Burssens; E Van Herzele; T Leenders; S Clockaerts; K Buedts; G Vandeputte; J Victor

doi:10.1016/j.fas.2017.02.006

Weightbearing CT in normal hindfoot alignment - Presence of a constitutional valgus?

Foot Ankle Surg. 2018 Jun;24(3):213-218. doi: 10.1016/j.fas.2017.02.006. Epub 2017 Feb 16.

Authors

A Burssens¹, E Van Herzele², T Leenders³, S Clockaerts⁴, K Buedts⁵, G Vandeputte⁶, J Victor²

Affiliations

¹ Department of Orthopaedic Surgery, Ghent University Hospital, De Pintelaan 185, 9000 Gent, Belgium. Electronic address: arne.burssens@ugent.be.
² Department of Orthopaedic Surgery, Ghent University Hospital, De Pintelaan 185, 9000 Gent, Belgium.
³ AZ Monica, Florent Pauwelslei 21, 2100 Deurne, Belgium.
⁴ AZ Groeninge, Burgemeester Vercruysselaan 5, 8500 Kortrijk, Belgium.
⁵ ZNA Middelheim, Lindendreef 1, 2020 Antwerpen, Belgium.
⁶ Department of Orthopaedic Surgery, H.-Hartziekenhuis, Mechelstraat 24, 2500 Lier, Belgium.

PMID: 29409213
DOI: 10.1016/j.fas.2017.02.006

Abstract

Background: The normal hindfoot angle is estimated between 2° and 6° of valgus in the general population. These results are solely based on clinical findings and plain radiographs. The purpose of this study is to assess the hindfoot alignment using weightbear CT.

Methods: Forty-eight patients, mean age of 39.6±13.2 years, with clinical and radiological absence of hindfoot pathology were included. A weightbear CT was obtained and allowed to measure the anatomical tibia axis (TAx) and the hindfoot alignment (HA). The HA was firstly determined using the inferior point of the calcaneus (HA_IC). A density measurement of this area was subsequently performed to analyze if this point concurred with an increased ossification, indicating a higher load exposure. Secondly the HA was determined by dividing the calcaneus in the long axial view (HALA) and compared to the (HA_IC) to point out any possible differences attributed to the measurement method. Reliability was assessed using an intra class correlation coefficient (ICC).

Results: The mean HA_IC equaled 0.79° of valgus±3.2 (ICC_{HA IC}=0.73) with a mean TAx of 2.7° varus±2.1 (ICCTA=0.76). The HALA equaled 9.1° of valgus±4.8 (ICCHA LA=0.71) and differed significantly by a P<0.001 from the HA_IC, which showed a more neutral alignment. Correlation between both was shown to be good by a Spearman's correlation coefficient of 0.74. The mean density of the inferior calcaneal area equaled 271.3±84.1 and was significantly higher than the regional calcaneal area (P<0.001).

Conclusions: These results show a more neutral alignment of the hindfoot in this group of non-symptomatic feet as opposed to the generally accepted constitutional valgus. This could have repercussion on hindfoot position during fusion or in quantifying the correction of a malalignment. The inferior calcaneus point in this can be used during pre-operative planning of a hindfoot correction as an anatomical landmark due to its shown influence on load transfer.

Keywords: Hindfoot alignment; Hindfoot correction; Normal alignment; Weightbear CT.

MeSH terms

Adult
Aged
Female
Foot Deformities, Acquired / diagnosis*
Foot Deformities, Acquired / physiopathology
Foot Deformities, Acquired / surgery
Humans
Male
Reproducibility of Results
Tomography, X-Ray Computed / methods*
Weight-Bearing / physiology*