title: Intermittent KoldBlue cryotherapy of 3x10 min changes mid-portion Achilles tendon microcirculation.
abstract: BACKGROUND
  Neovascularisation and microcirculatory changes have been reported in Achilles tendinopathy. Cryotherapy and compression, as part of a rest, ice, compression and elevation regimen, are shown to decrease pain and improve function. However, the microcirculatory changes following a given dosage of cryotherapy on mid-portion Achilles tendon remain unclear.
  
  
  METHODS
  Prospective clinical cohort study, level of evidence 2.
  
  
  METHODS
  30 people (12 males, 33 (SD 12) years, body mass index 25.6 (5.3) kg/m2) were included in the cohort. 3x10 min KoldBlue ankle-cooling bandages were applied and microcirculation of Achilles tendon mid-portion was real-time and continuously assessed using a laser-Doppler-spectrophotometry system (O2C, Germany).
  
  
  RESULTS
  Superficial capillary blood flow was reduced from 42 to 6, 5 and 3 relative units (rU) in the first, second and third cryotherapy periods, respectively (-65%, p = 0.001), with no significant capillary hyperaemia. Deep capillary tendon blood flow was reduced from 180 to 82, 53 and 52 rU (-71%, p = 0.001) within 6-9 min of application without hyperaemia. Superficial tendon oxygen saturation dropped significantly from 43% to 26%, 18% and 11% (p = 0.001) after repetitive cryotherapy, with persisting increase of tendon oxygenation during rewarming (51%, 49% and 54%, p = 0.077) up to 27% of the baseline level. At 8 mm tendon depth, cryotherapy preserved local oxygenation. Relative postcapillary venous tendon filling pressures were favourably reduced from 41 (11) to 31, 28 and 26 rU (-36%, p = 0.001) superficially and from 56 (11) to 45, 46 and 48 rU (-18%, p = 0.001) in deep capillary blood flow during cryotherapy, facilitating capillary venous clearance.
  
  
  CONCLUSIONS
  Intermittent cryotherapy of 3x10 min significantly decreases local Achilles tendon mid-portion capillary blood flow by 71%. Within 2 min of rewarming, tendon oxygen saturation is re-established following cryotherapy. Postcapillary venous filling pressures are reduced during cryotherapy, favouring capillary venous outflow of the healthy Achilles tendon.
authors.affiliation: Sports Traumatology of the Hand and Wrist, Plastic, Hand and Reconstructive Surgery, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany. kknobi@yahoo.com
authors.forename: Karsten
authors.initials: K
authors.lastname: Knobloch
authors.forename: Ruth
authors.initials: R
authors.lastname: Grasemann
authors.forename: Marcus
authors.initials: M
authors.lastname: Spies
authors.forename: Peter M
authors.initials: PM
authors.lastname: Vogt
mesh_terms: D000125:Achilles Tendon / Q000098:blood supply* / Q000503:physiopathology; D000328:Adult; D001458:Bandages; D015331:Cohort Studies; D003080:Cold Temperature; D017679:Cryotherapy / Q000295:instrumentation* / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D010101:Oxygen Consumption; D010465:Perception; D011446:Prospective Studies; D052256:Tendinopathy / Q000503:physiopathology / Q000628:therapy*; D013997:Time Factors; D016896:Treatment Outcome; D014690:Venous Pressure