title: Functional weight-bearing mobilization after Achilles tendon rupture enhances early healing response: a single-blinded randomized controlled trial.
abstract: OBJECTIVE
  Functional weight-bearing mobilization may improve repair of Achilles tendon rupture (ATR), but the underlying mechanisms and outcome were unknown. We hypothesized that functional weight-bearing mobilization by means of increased metabolism could improve both early and long-term healing.
  
  
  METHODS
  In this prospective randomized controlled trial, patients with acute ATR were randomized to either direct post-operative functional weight-bearing mobilization (n = 27) in an orthosis or to non-weight-bearing (n = 29) plaster cast immobilization. During the first two post-operative weeks, 15°-30° of plantar flexion was allowed and encouraged in the functional weight-bearing mobilization group. At 2 weeks, patients in the non-weight-bearing cast immobilization group received a stiff orthosis, while the functional weight-bearing mobilization group continued with increased range of motion. At 6 weeks, all patients discontinued immobilization. At 2 weeks, healing metabolites and markers of procollagen type I (PINP) and III (PIIINP) were examined using microdialysis. At 6 and 12 months, functional outcome using heel-rise test was assessed.
  
  
  RESULTS
  Healing tendons of both groups exhibited increased levels of metabolites glutamate, lactate, pyruvate, and of PIIINP (all p < 0.05). Patients in functional weight-bearing mobilization group demonstrated significantly higher concentrations of glutamate compared to the non-weight-bearing cast immobilization group (p = 0.045).The upregulated glutamate levels were significantly correlated with the concentrations of PINP (r = 0.5, p = 0.002) as well as with improved functional outcome at 6 months (r = 0.4; p = 0.014). Heel-rise tests at 6 and 12 months did not display any differences between the two groups.
  
  
  CONCLUSIONS
  Functional weight-bearing mobilization enhanced the early healing response of ATR. In addition, early ankle range of motion was improved without the risk of Achilles tendon elongation and without altering long-term functional outcome. The relationship between functional weight-bearing mobilization-induced upregulation of glutamate and enhanced healing suggests novel opportunities to optimize post-operative rehabilitation.
authors.affiliation: Orthopaedics Department, Orthopedium, Delft, The Netherlands.
authors.forename: Kars P
authors.initials: KP
authors.lastname: Valkering
authors.affiliation: Physiotherapy Department, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Susanna
authors.initials: S
authors.lastname: Aufwerber
authors.affiliation: Orthopaedics Department, School of Medicine, Magna Graecia University, Catanzaro, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Ranuccio
authors.affiliation: Orthopaedics Department, Azienda University Hospital Parma, Parma, Italy.
authors.forename: Enricomaria
authors.initials: E
authors.lastname: Lunini
authors.affiliation: Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Edman
authors.affiliation: Integrative Orthopedic Laboratory, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden. paul.ackermann@karolinska.se.|Orthopedic Department, Karolinska University Hospital, 171 76, Stockholm, Sweden. paul.ackermann@karolinska.se.
authors.forename: Paul W
authors.initials: PW
authors.lastname: Ackermann
mesh_terms: D000125:Achilles Tendon / Q000293:injuries* / Q000378:metabolism / Q000502:physiology / Q000601:surgery*; D000328:Adult; D000842:Ankle / Q000502:physiology / Q000601:surgery; D002370:Casts, Surgical; D005260:Female; D006801:Humans; D007103:Immobilization; D019344:Lactic Acid / Q000378:metabolism; D008297:Male; D017551:Microdialysis; D011446:Prospective Studies; D016059:Range of Motion, Articular; D012421:Rupture / Q000601:surgery; D016037:Single-Blind Method; D016896:Treatment Outcome; D016474:Weight-Bearing / Q000502:physiology*; D014945:Wound Healing / Q000502:physiology*
chemical_list: D019344:Lactic Acid
keywords: Achilles tendon; Collagen; Metabolism; Metabolite; Microdialysis; Revalidation; Rupture