# Height and weight predict cross‐sectional area of the peroneus brevis and longus tendons: Magnetic resonance imaging‐based analysis of 164 adults

## TL;DR

This study finds that height and weight predict the size of certain ankle tendons, which could help in planning tendon grafts and assessing post-surgery function.

## Contribution

The study identifies height and weight as reliable predictors of peroneal tendon cross-sectional area using MRI data from 164 adults.

## Key findings

- Height and age are significant predictors of peroneus brevis tendon size.
- Weight is a significant predictor of peroneus longus tendon size.
- BMI does not significantly correlate with tendon cross-sectional area.

## Abstract

To determine whether height, weight and body mass index (BMI) are associated with the cross‐sectional area of the peroneus brevis and longus tendons on magnetic resonance imaging (MRI). Understanding these associations may assist in autograft selection and evaluation of residual tendon function after graft harvest.

This retrospective study included 164 adult patients (mean age 41.6 ± 15.7 years; 52% female) who underwent 3T ankle MRI between 2018 and 2024. Patients with peroneal tendon pathology (e.g., split tears, tendinosis), prior surgery or artefacts (e.g., motion or metal‐related signal loss) were excluded. Cross‐sectional areas were measured 1 cm above the lateral malleolus on axial proton density‐weighted images. Height and weight were obtained from pre‐MRI exam documentation. Associations with tendon cross‐sectional area were evaluated using multivariable linear regression models adjusted for age and side.

Mean cross‐sectional areas were 14.0 ± 4.2 mm² for the peroneus brevis and 19.3 ± 4.7 mm² for the peroneus longus. Peroneus brevis area was significantly associated with height (β = 12.9 mm²/m, p < 0.001) and age (β = 0.06 mm²/year, p < 0.001). Peroneus longus area was associated with weight (β = 0.07 mm²/kg, p = 0.01). No significant associations were found with BMI. All findings were robust in sensitivity analyses.

Height and weight are reliable predictors of peroneal tendon size; BMI is not. MRI is a standardised, noninvasive tool for individualised graft planning and assessment of postoperative tendon integrity. These findings may assist in autograft planning and in evaluating residual tendon function after graft harvest.

Level III.

Weight predicts peroneus longus size, height and age predict peroneus brevis size, and body mass index shows no significant association—based on magnetic resonance imaging analysis of 164 healthy adults. Scatterplots showing the relationship between tendon cross‐sectional area and body mass index, weight and height. Left panels: peroneus brevis; right: peroneus longus. Each point represents one individual; dashed lines show linear regression trends.