title: Long-term biomechanical outcomes after Achilles tendon ruptures.
abstract: OBJECTIVE
  The ideal treatment for Achilles tendon ruptures is still unknown. Biomechanical were correlated to radiological and clinical parameters to study outcomes.
  
  
  METHODS
  In this retrospective, assessor-blinded multi-centre cohort study, 52 patients with unilateral Achilles tendon rupture were assessed, each at least 3 years after injury. Patients underwent open surgery, percutaneous surgery or non-surgical treatment of Achilles tendon rupture. Both legs underwent plantar pressure distribution and isokinetic measures. Demographic parameters, maximum calf circumference (MCC) and clinical scores (American Orthopaedic Foot and Ankle Society, Achilles tendon rupture score, Hannover) were also evaluated. Complications were not assessed.
  
  
  RESULTS
  Peak plantar flexion torque (PPFT) was significantly weaker on the treated side compared to the untreated leg [80.4 ± 29.7 Nm (mean ± SD) vs. 92.1 ± 27.4 Nm, p < 0.0001]. PPFT and push-off force (POFF) were not different between treatment groups nor was there a leg difference in POFF alone. There was only a weak correlation of clinical scores and PPFT or POFF, respectively. MCC correlated significantly with both PPFT (R (2) = 0.21, p = 0.01) and POFF (R (2) = 0.29, p < 0.0001). POFF appeared to be a predictor of PPFT (R (2) = 0.31, p < 0.0001). Open surgery outperformed non-surgical treatment in terms of centre-of-pressure line (p = 0.007), torque per muscle volume (p = 0.04) and relative POFF per body weight (p = 0.02) and relative in side comparison (p = 0.03).
  
  
  CONCLUSIONS
  Clinical scores do not predict biomechanical outcomes. Clinically measured MCC is a good predictor of PPFT and POFF and can easily be used in clinical practice. Relative POFF in side comparison as well as per body weight favours surgical treatment.
authors.affiliation: Orthopaedic Department, University Hospital Basel, University of Basel, Spitalstrasse 21, 4031, Basel, Switzerland, Claudio.Rosso@unibas.ch.
authors.forename: Claudio
authors.initials: C
authors.lastname: Rosso
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Buckland
authors.forename: Caroline
authors.initials: C
authors.lastname: Polzer
authors.forename: Patrick
authors.initials: P
authors.lastname: Sadoghi
authors.forename: Reinhard
authors.initials: R
authors.lastname: Schuh
authors.forename: Lukas
authors.initials: L
authors.lastname: Weisskopf
authors.forename: Patrick
authors.initials: P
authors.lastname: Vavken
authors.forename: Victor
authors.initials: V
authors.lastname: Valderrabano
mesh_terms: D000125:Achilles Tendon / Q000293:injuries / Q000503:physiopathology* / Q000601:surgery; D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012421:Rupture; D013708:Tendon Injuries / Q000503:physiopathology* / Q000601:surgery / Q000628:therapy; D016896:Treatment Outcome; D055815:Young Adult