title: Interosseous membrane window size for tibialis posterior tendon transfer-Geometrical and MRI analysis.
abstract: BACKGROUND
  Tibialis posterior (TP) tendon transfer through the interosseous membrane is commonly performed in Charcot-Marie-Tooth disease. In order to avoid entrapment of this tendon, no clear recommendation relative to the interosseous membrane (IOM) incision size has been made.
  
  
  OBJECTIVE
  Analyze the TP size at the transfer level and therefore determine the most adequate IOM window size to avoid muscle entrapment.
  
  
  METHODS
  Eleven lower extremity magnetic resonances were analyzed. TP muscle measurements were made in axial views, obtaining the medial-lateral and antero-posterior diameter at various distances from the medial malleolus tip. The distance from the posterior to anterior compartment was also measured. These measurements were applied to a mathematical model to predict the IOM window size necessary to allow an ample TP passage in an oblique direction.
  
  
  RESULTS
  The average tendon diameter (confidence-interval) at 15cm proximal to the medial malleolus tip was 19.47mm (17.47-21.48). The deep posterior compartment to anterior compartment distance was 10.97mm (9.03-12.90). Using a mathematical model, the estimated IOM window size ranges from 4.2 to 4.9cm.
  
  
  CONCLUSIONS
  The IOM window size is of utmost importance in trans-membrane TP transfers, given that if equal or smaller than the transposed tendon oblique diameter, a high entrapment risk exists. A membrane window of 5cm or 2.5 times the size of the tendon diameter should be performed in order to theoretically diminish this complication.
authors: Clínica Alemana-Universidad del Desarrollo, Foot and Ankle Surgeon, Chile. Electronic address: pwagner@alemana.cl.
authors: Pablo
authors: P
authors: Wagner
authors: Clínica Alemana-Universidad del Desarrollo, Foot and Ankle Surgeon, Chile.
authors: Cristian
authors: C
authors: Ortiz
authors: Clínica Alemana-Universidad del Desarrollo, Orthopaedic Surgeon, Chile.
authors: Omar
authors: O
authors: Vela
authors: Second Year Resident, Orthopaedic Surgery, Clínica Alemana-Universidad del Desarrollo, Chile.
authors: Paul
authors: P
authors: Arias
authors: Clínica Alemana-Universidad del Desarrollo, Foot and Ankle Surgeon, Chile.
authors: Diego
authors: D
authors: Zanolli
authors: Clínica Alemana-Universidad del Desarrollo, Foot and Ankle Surgeon, Chile.
authors: Emilio
authors: E
authors: Wagner
mesh_terms: D000293:Adolescent; D000328:Adult; D000843:Ankle Joint / Q000000981:diagnostic imaging* / Q000601:surgery; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D037081:Posterior Tibial Tendon Dysfunction / Q000000981:diagnostic imaging* / Q000601:surgery*; D011183:Postoperative Complications / Q000517:prevention & control; D011379:Prognosis; D018570:Risk Assessment; D012494:Sampling Studies; D013709:Tendon Transfer / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult
keywords: Drop foot; Interosseous membrane; Tendon entrapment; Tendon transfer; Tibialis posterior tendon transfer