The effect of foot type on the Achilles tendon moment arm and biomechanics.
Achilles tendon moment arm
Normal-arched foot
Pes cavus
Pes planus
Static model
Weight-bearing radiographs
Journal
Foot (Edinburgh, Scotland)
ISSN: 1532-2963
Titre abrégé: Foot (Edinb)
Pays: Scotland
ID NLM: 9109564
Informations de publication
Date de publication:
Mar 2019
Mar 2019
Historique:
received:
04
06
2018
revised:
30
08
2018
accepted:
08
10
2018
pubmed:
9
3
2019
medline:
18
12
2019
entrez:
9
3
2019
Statut:
ppublish
Résumé
The aim was to calculate the Achilles tendon moment arm in different degrees of plantarflexion for pes planus, pes cavus and normal arched feet. 99 patients (99 radiographs; 40 males, 59 females; mean age 49 years, SD 15) with a healthy ankle joint and a preoperative weightbearing lateral radiograph of the foot were included. Three groups (pes planus, pes cavus and normal-arched feet) with equal sample sizes (n=33) were formed. On radiographs, the angle formed between a horizontal line and the line connecting the insertion of the Achilles tendon with the center of rotation of the ankle, was measured. The interrater reliabilities (ICC) of the angle alpha were compared on radiographs and on MRIs. Using the angle alpha, the Achilles tendon moment arm was calculated in different plantarflexion positions. The ICC of alpha was higher on radiographs (0.84, [0.73-0.91]) than on MRIs (0.61, [0.27-0.81]). The average alpha was statistically significantly different (normal arched foot 31 degrees (°), pes planus 24°, pes cavus 36°, p=0.021), resulting in a significant shorter Achilles tendon moment arm for pes cavus than for pes planus (p<0.0001) and normal arched feet (p=0.006) in neutral position. The data suggests that it is feasible to use radiographs to measure the Achilles tendon moment arm. The maximum Achilles tendon moment arm is reached at different angles of ankle flexion for pes cavus, pes planus and normal-arched feet. This has to be taken into consideration when planning surgeries.
Sections du résumé
BACKGROUND
BACKGROUND
The aim was to calculate the Achilles tendon moment arm in different degrees of plantarflexion for pes planus, pes cavus and normal arched feet.
METHODS
METHODS
99 patients (99 radiographs; 40 males, 59 females; mean age 49 years, SD 15) with a healthy ankle joint and a preoperative weightbearing lateral radiograph of the foot were included. Three groups (pes planus, pes cavus and normal-arched feet) with equal sample sizes (n=33) were formed. On radiographs, the angle formed between a horizontal line and the line connecting the insertion of the Achilles tendon with the center of rotation of the ankle, was measured. The interrater reliabilities (ICC) of the angle alpha were compared on radiographs and on MRIs. Using the angle alpha, the Achilles tendon moment arm was calculated in different plantarflexion positions.
RESULTS
RESULTS
The ICC of alpha was higher on radiographs (0.84, [0.73-0.91]) than on MRIs (0.61, [0.27-0.81]). The average alpha was statistically significantly different (normal arched foot 31 degrees (°), pes planus 24°, pes cavus 36°, p=0.021), resulting in a significant shorter Achilles tendon moment arm for pes cavus than for pes planus (p<0.0001) and normal arched feet (p=0.006) in neutral position.
CONCLUSION
CONCLUSIONS
The data suggests that it is feasible to use radiographs to measure the Achilles tendon moment arm. The maximum Achilles tendon moment arm is reached at different angles of ankle flexion for pes cavus, pes planus and normal-arched feet. This has to be taken into consideration when planning surgeries.
Identifiants
pubmed: 30849670
pii: S0958-2592(18)30075-0
doi: 10.1016/j.foot.2018.10.003
pii:
doi:
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
91-94Informations de copyright
Copyright © 2018 Elsevier Ltd. All rights reserved.