title: Microcirculation in healing and healthy Achilles tendon assessed with invasive laser doppler flowmetry.
abstract: BACKGROUND
  Achilles tendon (AT) rupture exhibits a prolonged healing process with varying clinical outcome. Reduced blood flow to the AT has been considered an underlying factor to AT rupture (ATR) and impaired healing. In vivo measurements using laser Doppler flowmetry (LDF) may be a viable method to assess blood flow in healthy and healing AT.
  
  
  METHODS
  29 persons were included in the study; 9 being ATR patients and 20 healthy subjects without any prior symptoms from the AT. Invasive LDF was used to determine the post-occlusive reactive hyperemia (PORH) in the paratenon after 15 minutes of occlusion of the lower extremities. ATR patients were examined two weeks post-operatively.
  
  
  RESULTS
  LDF-assessments demonstrated a significantly different (p < 0.001) PORH response in the healing- versus intact- and control AT. In the healing AT, a slow, flattened PORH was observed compared to a fast, high peak PORH in intact, healthy AT.
  
  
  CONCLUSIONS
  in vivo LDF appears to be a feasible method to assess alterations in blood flow in healing and intact AT. The healing ATs capability to react to an ischemic period is clearly impaired, which may be due to the trauma at injury and/or surgery or degenerative changes in the tendon.
authors.affiliation: Department of Orthopedic Surgery, Danderyd Hospital, Stockholm, Sweden.
authors.forename: Erica Domeij
authors.initials: ED
authors.lastname: Arverud
authors.affiliation: Department of Orthopedic Surgery, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Olof
authors.initials: O
authors.lastname: Persson-Lindell
authors.affiliation: Department of Orthopedic Surgery, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Fredrik
authors.initials: F
authors.lastname: Sundquist
authors.affiliation: Section of Diagnostic Imaging, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Fausto
authors.initials: F
authors.lastname: Labruto
authors.affiliation: Department of Neurobiology, Care Sciences, and Society, Centre of Family Medicine (CeFAM), Karolinska Institutet, Stockholm, Sweden.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Edman
authors.affiliation: Department of Orthopedic Surgery, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Paul W
authors.initials: PW
authors.lastname: Ackermann
keywords: blood flow; circulation; hyperemia; regeneration; rupture; tendon