title: Clinical failure after Dresden repair of mid-substance Achilles tendon rupture: human cadaveric testing.
abstract: OBJECTIVE
  The purpose of this study was to describe the angle of clinical failure during cyclical mobilization exercises in the Achilles tendon of human cadaveric specimens that were repaired using the Dresden technique and FiberWire®No. 2. The secondary aim was to identify the secure limit of mobilization, the type of failure, and the type of apposition.
  
  
  METHODS
  The lower limbs of eight males (mean age: 60.3 ± 6.3 years) were repaired with the Dresden technique following complete, percutaneous mid-substance Achilles tendon rupture. A basal tension of 10 N at 30° of plantarflexion was placed on each specimen. The angle of the ankle during clinical failure (tendon ends separation >5 mm) was then tested via cyclical exercises (i.e. 100 cycles between 30° and 15° of plantarflexion; 100 cycles between 15° of plantarflexion and 0°; 100 cycles between 0° and 15° of dorsiflexion; and 100 cycles between 15° of dorsiflexion and full dorsiflexion). Clinical failure was determined using the Laplacian edge detection filter, and the angle of clinical failure was obtained using a rotatory potentiometer aligned in relation to the intermalleolar axis of each foot specimen. The type of failure (knot, tendon, or suture) and apposition (termino-terminal or non-termino-terminal) were determined. Descriptive statistics were used to obtain the mean; standard deviation; 95 % confidence interval; 1st, 25th, 50th, 75th, and 100th percentiles; and the standard error of the mean for angle data. Proportions were used to describe the type of failure and apposition.
  
  
  RESULTS
  The main results were a mean angle of clinical failure equal to 12.5° of plantarflexion, a limit of mobilization equal to 14.0° of plantarflexion, tendon failure type, and non-termino-terminal apposition in all specimens.
  
  
  CONCLUSIONS
  While the mean angle of clinical failure in human cadaveric models was 12.5° of plantarflexion, after 14.0° of plantarflexion, the percutaneous Dresden technique was found insecure for cyclical mobilization exercises, with a 5 % range of error. These findings are clinically relevant as they provide mechanical limits for diminishing the risk of Achilles lengthening during immediate rehabilitation.
authors.affiliation: Carrera de Kinesiología, UDA Cs. de la Salud, Facultad de Medicina, Pontificia Universidad Católica, 7820436, Santiago, Chile. delafuentte@gmail.com.|Magister en Ciencias de la Ingeniería mención en Ingeniería Biomédica, Facultad de Ingeniería, Universidad de Valparaíso de Chile, 2362905, Valparaíso, Chile. delafuentte@gmail.com.
authors.forename: Carlos
authors.initials: C
authors.lastname: De la Fuente
authors.affiliation: Magister en Ciencias de la Ingeniería mención en Ingeniería Biomédica, Facultad de Ingeniería, Universidad de Valparaíso de Chile, 2362905, Valparaíso, Chile.|Programa de Quiropraxia, Facultad de Ciencias de la Salud, Universidad Central, 8370178, Santiago, Chile.|Facultad de Ciencias de la Salud, Universidad Iberoamericana de Ciencias y Tecnología, 8330440, Santiago, Chile.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Carreño
authors.affiliation: Anatomía, Facultad de Medicina, Universidad de Chile, 8330023, Santiago, Chile.
authors.forename: Miguel
authors.initials: M
authors.lastname: Soto
authors.affiliation: Traumatology Unit, Clínica Santa Maria, 7520378, Santiago, Chile.
authors.forename: Hugo
authors.initials: H
authors.lastname: Marambio
authors.affiliation: Anatomía, Facultad de Medicina, Universidad de Chile, 8330023, Santiago, Chile.|Foot and ankle service, Instituto Traumatológico "Teodoro Gebauer Weisser", 8340220, Santiago, Chile.|Traumatology Unit, Clínica Santa Maria, 7520378, Santiago, Chile.
authors.forename: Hugo
authors.initials: H
authors.lastname: Henríquez
mesh_terms: D000125:Achilles Tendon / Q000293:injuries* / Q000503:physiopathology / Q000601:surgery*; D000842:Ankle / Q000503:physiopathology; D005081:Exercise Therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D012421:Rupture / Q000503:physiopathology / Q000601:surgery; D013536:Suture Techniques; D017211:Treatment Failure
keywords: Achilles tendon; Clinical failure; Dresden repair; Mobilization exercises