title: The influence of the Peroneus Longus muscle on the foot under axial loading: A CT evaluated dynamic cadaveric model study.
abstract: Subtle hypermobility of the first tarsometatarsal joint can occur concomitantly with other pathologies and may be difficult to diagnose. Peroneus Longus muscle might influence stability of this joint. Collapse of the medial longitudinal arch is common in flatfoot deformity and the muscle might also play a role in correcting Meary's angle.
  
  
  
  A radiolucent frame was used to simulate weightbearing during CT examination. Eight pairs fresh-frozen lower legs were imaged in neutral position under non-weightbearing (75N), weightbearing (700N) and with 15kg weights hung from Peroneus Longus tendon. Measurements included first metatarsal rotation, intermetatarsal angle, first tarsometatarsal joint subluxation and Meary's angle.
  
  
  
  Weightbearing significantly increased Meary's angle and significantly decreased first tarsometatarsal joint subluxation (both P<0.01). Pulling Peroneus Longus tendon significantly increased first metatarsal rotation (P<0.01), significantly decreased the intermetatarsal angle (P<0.01) and increased non-significantly Meary's angle (P=0.52).
  
  
  
  A considerable effect weightbearing has on the medial longitudinal arch and first tarsometatarsal joint was observed. Pulling Peroneus Longus tendon improved first metatarsal subluxation but increased its rotation. The study calls into question the importance of this tendon in maintaining the medial longitudinal arch and raises concerns about rotational deformity of the first metatarsal following hallux valgus correction without first tarsometatarsal arthrodesis.
  
  
  
  Study outcomes will provide more insight in foot pathology.
  
  
  
  Weightbearing affects anatomy of the foot. No reliable information is available concerning the influence of the Peroneus muscle.
  
  
  
  This study investigates the influence of weightbearing and the impact the Peroneus muscle on the anatomy of the foot.
authors.affiliation: AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos, Switzerland. Electronic address: koendullaert@gmail.com.
authors.forename: K
authors.initials: K
authors.lastname: Dullaert
authors.affiliation: AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos, Switzerland. Electronic address: hagenje@ortho.ufl.edu.
authors.forename: J
authors.initials: J
authors.lastname: Hagen
authors.affiliation: Catholic Clinic Mainz, Department of Foot and Ankle Surgery, KKM Mainz, An der Goldgrube 11, , 55131 Mainz, Germany; Department of Trauma, Hand and Reconstructive Surgery, University Hospital Jena, Bachstraße 18, 07743 Jena, Germany. Electronic address: k-klos@kkmainz.de.
authors.forename: K
authors.initials: K
authors.lastname: Klos
authors.affiliation: AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos, Switzerland. Electronic address: boyko.gueorguiev@aofoundation.org.
authors.forename: B
authors.initials: B
authors.lastname: Gueorguiev
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, University Hospital Jena, Bachstraße 18, 07743 Jena, Germany. Electronic address: mark.lenz@med.uni-jena.de.
authors.forename: M
authors.initials: M
authors.lastname: Lenz
authors.affiliation: AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos, Switzerland. Electronic address: geoff.richards@aofoundation.org.
authors.forename: R G
authors.initials: RG
authors.lastname: Richards
authors.affiliation: Catholic Clinic Mainz, Department of Foot and Ankle Surgery, KKM Mainz, An der Goldgrube 11, , 55131 Mainz, Germany. Electronic address: p-simons@kkmainz.de.
authors.forename: P
authors.initials: P
authors.lastname: Simons
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D005260:Female; D005413:Flatfoot / Q000503:physiopathology; D005528:Foot / Q000000981:diagnostic imaging / Q000502:physiology*; D006801:Humans; D004204:Joint Dislocations / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000502:physiology*; D012399:Rotation; D013640:Tarsal Joints / Q000000981:diagnostic imaging / Q000502:physiology*; D013710:Tendons / Q000000981:diagnostic imaging / Q000502:physiology; D014057:Tomography, X-Ray Computed; D016474:Weight-Bearing
keywords: Biomechanical study; First ray instability; Hallux valgus; Medial longitudinal arch; Peroneus Longus function