A cadaver study of the FHL and FDL tendons crossing A contribution to neglected Achilles tendon rupt

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A cadaver study of the FHL and FDL tendons
crossingA contribution to neglected Achilles
tendon rupture surgeries

• Hart R, Filan P
• Dept. of Orthopaedics and Traumatology
• General Hospital
• Znojmo
• Czech Republic

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Introduction

• A. K. Henry described the region of the cross
  connection between FHL tendon and FDL tendon in
  the mid foot
• the crossing has been called the master knot
• Henry A.K. Extensile
  exposure.
• 3rd Ed. Edinbugh
  Churchill Livingstone. 1995, p 300-308.

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Introduction
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Aim

• to describe the exact structure of the FHL and
  FDL tendons connection and to investigate the
  possibilities of a tendon transfer
• especially concentrating on the repair of the
  neglected Achilles tendon ruptures by Wapners
  two - incision technique (1993) of the FHL
  transfer first described by Hansen (1991)

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Introduction
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Introduction

• FHL - is a strong
  flexor - has a tendon long enough to bridge
  the Achilles tendon defect - proceeds the
  same direction as triceps surae muscle -
  has a more distal belly ? enhances
  vascularity and healing - is in phase
  with the triceps surae during the gait cycle

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Introduction
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Introduction

• Grays Anatomy

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Introduction

• Netter Frank

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Methods

• both feet in 30 cadavers (17 men, 13 women)
• measurements on FHL
• the distance from the FHL muscle-tendon junction
  to the appearance of the connection with FDL
• the distance from the appearance of the
  connection with FDL to the FHL insertion to the
  distal phalanx

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Methods

• comparison of these distances to the foot length

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Results

• no connection between FHL and FDL tendons
  proximally to the branching of FDL for fingers

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Results

• tendon connection of the FHL to the FDL went to
  -
  only the 2nd ray FDL tendon 62 (37 feet)
  
  - both, the 2nd and 3rd ray
  tendons 38 (23 feet)

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Results

• difference between both feet -
  4 cadavers (13 )

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Results

• A - the distance on FHL from the appearance of
  the connection with FDL to the FHL insertion to
  the distal phalanx
• 13,8cm (range, 9,8 - 19,4)
• this distance is not appropriate for planning of
  the surgical approach to the FHL and FDL crossing
  because of wide range of values

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Results

• the distance from the FHL muscle-tendon junction
  to the appearance of the connection with FDL
  17,9cm (range, 15,7 19,6)
• the proximal part of FHL tendon is long enough
  for reconstruction of the Achilles tendon defect

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Results

• B (tendons connection calcaneal tuberosity)
  9,2cm (range, 7,1 12,2)
• C (FHL insertion - calcaneal tuberosity)
  16,5cm (range, 13,4 18,6)

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Results

• B/C ratio - mean, SD 0,56 0,067 -
  median (medium value) 0,54 - modus (most
  frequent value) 0,52

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Discussion

• we did not find any connection described in
  anatomical study by E. OSullivan (U.K.)
  proximally to the FDL branching for fingers

E. O'Sullivan, R. Carare-Nnadi, J. Greenslade, G.
Bowyer Clinical significance of variations in
the interconnections between flexor digitorum
longus and flexor hallucis longus in the
region of the knot of Henry. Clinical Anatomy 18
121 125, 2005
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Discussion

• we did not observe any connection type and even
  the absence of any connection between FHL and FDL
  described by B.G. LaRue (Canada)

LaRue B.G., Anctil E.P. Distal anatomical
relationship of the flexor hallucis longus and
flexor digitorum longus tendons. Foot Ankle Int.
27(7) 528 - 32. Jul 2006
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Conclusions

• suture of both tendons distally to the cut of
  transferred tendon is mandatory to keep the
  correct function of all toes
• FHB and FDB muscles might be lacking to
  compensate the flexion strength of involved toes

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Conclusions

• leaving the connection without any suture in case
  of FHL transfer (same if the FHL cut is
  proximally or distally to the connection) causes
  the loss of distal phalanx flexion of the big toe
  and reduces the strength of its flexion

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Conclusions

• leaving the connection without any suture in case
  of FDL transfer causes the loss of distal phalanx
  flexion of the two or three lateral toes,
  respectively

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Conclusions

• less invasive surgery - most frequent
  location of the connection appearance on FHL is
  to be found at a rough estimate of the
  middistance between calcaneal tuberosity and
  the FHL insertion to the distal phalanx

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Thank you