title: Do changes in dynamic plantar pressure distribution, strength capacity and postural control after intra-articular calcaneal fracture correlate with clinical and radiological outcome?
abstract: Fractures of the calcaneus are often associated with serious permanent disability, a considerable reduction in quality of life, and high socio-economic cost. Although some studies have already reported changes in plantar pressure distribution after calcaneal fracture, no investigation has yet focused on the patient's strength and postural control.
  
  
  METHODS
  60 patients with unilateral, operatively treated, intra-articular calcaneal fractures were clinically and biomechanically evaluated >1 year postoperatively (physical examination, SF-36, AOFAS score, lower leg isokinetic strength, postural control and gait analysis including plantar pressure distribution). Results were correlated to clinical outcome and preoperative radiological findings (Böhler angle, Zwipp and Sanders Score).
  
  
  RESULTS
  Clinical examination revealed a statistically significant reduction in range of motion at the tibiotalar and the subtalar joint on the affected side. Additionally, there was a statistically significant reduction of plantar flexor peak torque of the injured compared to the uninjured limb (p<0.001) as well as a reduction in postural control that was also more pronounced on the initially injured side (standing duration 4.2±2.9s vs. 7.6±2.1s, p<0.05). Plantar pressure measurements revealed a statistically significant pressure reduction at the hindfoot (p=0.0007) and a pressure increase at the midfoot (p=0.0001) and beneath the lateral forefoot (p=0.037) of the injured foot. There was only a weak correlation between radiological classifications and clinical outcome but a moderate correlation between strength differences and the clinical questionnaires (CC 0.27-0.4) as well as between standing duration and the clinical questionnaires. Although thigh circumference was also reduced on the injured side, there was no important relationship between changes in lower leg circumference and strength suggesting that measurement of leg circumference may not be a valid assessment of maximum strength deficits. Self-selected walking speed was the parameter that showed the best correlation with clinical outcome (AOFAS score).
  
  
  CONCLUSIONS
  Calcaneal fractures are associated with a significant reduction in ankle joint ROM, plantar flexion strength and postural control. These impairments seem to be highly relevant to the patients. Restoration of muscular strength and proprioception should therefore be aggressively addressed in the rehabilitation process after these fractures.
authors.affiliation: Albert-Ludwigs University Freiburg, Department Orthopaedics and Traumatology, Freiburg, Germany. anja.hirschmueller@uniklinik-freiburg.de
authors.forename: Anja
authors.initials: A
authors.lastname: Hirschmüller
authors.forename: Lukas
authors.initials: L
authors.lastname: Konstantinidis
authors.forename: Heiner
authors.initials: H
authors.lastname: Baur
authors.forename: Steffen
authors.initials: S
authors.lastname: Müller
authors.forename: Alexander
authors.initials: A
authors.lastname: Mehlhorn
authors.forename: Julia
authors.initials: J
authors.lastname: Kontermann
authors.forename: Ulrich
authors.initials: U
authors.lastname: Grosse
authors.forename: N P
authors.initials: NP
authors.lastname: Südkamp
authors.forename: Peter
authors.initials: P
authors.lastname: Helwig
mesh_terms: D000328:Adult; D000843:Ankle Joint / Q000503:physiopathology; D001696:Biomechanical Phenomena; D002111:Calcaneus / Q000000981:diagnostic imaging / Q000293:injuries* / Q000601:surgery; D005163:Factor Analysis, Statistical; D005260:Female; D005500:Follow-Up Studies; D005593:Fracture Fixation, Internal / Q000379:methods; D005684:Gait / Q000502:physiology; D006801:Humans; D015601:Injury Severity Score; D057072:Intra-Articular Fractures / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology; D011187:Posture / Q000502:physiology; D011312:Pressure; D011434:Proprioception; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology*; D020127:Recovery of Function; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires; D013640:Tarsal Joints / Q000503:physiopathology; D019415:Torque; D016896:Treatment Outcome; D016138:Walking / Q000502:physiology