The Mechanical Properties of Finger Flexor Tendons and Development of Stronger Tendon Suturing Techniques

  • Andrew A. Amis
Part of the NATO ASI Series book series (NSSA, volume 256)


As the finger flexor tendons pass distally from the flexor muscles of the forearm through the wrist and fingers to their insertions in the phalanges they are progressively constricted into tighter surrounding tissues. This passage through the carpal tunnel and into the fibro-osseous canals of the fingers is accompanied by progressively increasing difficulty in repairing the tendons and obtaining good functional results afterwards, so much so that the area between the distal crease of the palm of the hand and the distal interphalangeal joint was known as “no man’s land” by surgeons for many years.50,51 The paucity of tendon vascularity in much of this zone23 causes a tendency for the surrounding tissues to become linked to the repair site by scar tissue adhesions, which can bring nutrition by vascular perfusion but prevent the tendons from moving adequately.37 Anything less than perfection in surgical technique encourages this tendency, and factors such as rough handling of the surface of the tendon and the presence of suture material on the surface of the tendon have been implicated in causing poor results.33 A further factor is that the tightness of the pulleys, which hold the tendons close to the bones when the finger is flexed,14 means that the surgeon must not make a bulky repair. Knots in the suture material or protruding edges of the cut tendon ends will catch on the edges of the pulleys, preventing finger flexion.3 The requirements for lack of repair bulk and little handling of the tendon mean that surgeons cannot use many strands of thick sutures to try to make their repairs strong, and this leads to repairs failing after the operation.


Suture Material Flexor Tendon Flexor Digitorum Superficialis Rupture Force Flexor Digitorum Profundus 
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  1. 1.
    M. Abrahams, Mechanical behaviour of tendon in vitro, a preliminary report, Med. Biol. Eng. 5:433 (1967).PubMedCrossRefGoogle Scholar
  2. 2.
    A.A. Amis, Variation of finger forces in maximal isometric grasp tests on a range of cylinder diameters, J. Biomed. Eng. 9:313 (1987).PubMedCrossRefGoogle Scholar
  3. 3.
    A.A. Amis, and M.M. Jones, The interior of the finger flexor tendon sheath and the functional significance of its structure, J. Bone Joint Surg. 70B:583 (1988).Google Scholar
  4. 4.
    K.N. An, E.Y. Chao, W.P. Cooney, and R.L. Linscheid, Normative model of human hand for biomechanical analysis, J. Biomech. 12:775 (1979).PubMedCrossRefGoogle Scholar
  5. 5.
    J.V. Benedict, L.B. Walker, and E.H. Harris, Stress-strain characteristics and tensile strength of unembalmed human tendon, J. Biomech. 1:53 (1968).PubMedCrossRefGoogle Scholar
  6. 6.
    N. Berme, J.P. Paul, and W.K. Purves, A biomechanical analysis of the metacarpophalangeal joint, J. Biomech. 10:409 (1977).PubMedCrossRefGoogle Scholar
  7. 7.
    R.B. Bourne, H. Bitar, P.R. Andreae, L.M. Martin, J.B. Finlay, and F. Marquis, In-vivo comparison of four absorbable sutures: Vicryl, Dexon plus, Maxon and PDS, Can. J. Surg. 31:43 (1988).PubMedGoogle Scholar
  8. 8.
    J.H. Boy es, J.N. Wilson, and J.W. Smith, Flexor tendon ruptures in the forearm and hand, J. Bone Joint Surg. 42A:637 (1960).PubMedGoogle Scholar
  9. 9.
    S. Bunnel, “Surgery of the Hand,” Fifth edition, Lippincott, Philadelphia, (1956).Google Scholar
  10. 10.
    R.E. Caroll, and R.M. Match, Common errors in the management of wrist laceration, J. Trauma 14:553 (1974).CrossRefGoogle Scholar
  11. 11.
    E.Y. Chao, and K.N. An, Determination of internal forces in human hand, J. Eng. Mech., Divn. ASCE 104:255 (1978).Google Scholar
  12. 12.
    E.Y. Chao, J.D. Opgrande, and F.E. Axmear, Three-dimensional force analysis of finger joints in selected isometric hand functions, J. Biomech. 9:387 (1976).PubMedCrossRefGoogle Scholar
  13. 13.
    A.E. Cronkite, The tensile strength of human tendons, Anat. Rec. 64:173 (1936).CrossRefGoogle Scholar
  14. 14.
    J.R. Doyle, and W. Blythe, The finger flexor sheath and pulleys: anatomy and function, in: “Symposium on Tendon Surgery in the Hand”, American Academy of Orthopaedic Surgeons, C.V. Mosby, St. Louis, (1975).Google Scholar
  15. 15.
    A. Ejeskar, Flexor tendon repair in no-man’s land: results of primary repair with controlled mobilisation, J. Hand Surg. 9A:171 (1984).Google Scholar
  16. 16.
    J.H. Evans, and J.C. Barbenel, Structural and mechanical properties of tendon related to function, Equine Vet. J. 7:1 (1975).PubMedCrossRefGoogle Scholar
  17. 17.
    R.C. Folmar, C.L. Nelson, and G.S. Phalen, Ruptures of the flexor tendons in hands of non-rheumatoid patients, J. Bone Joint Surg. 54A:579 (1972).PubMedGoogle Scholar
  18. 18.
    R.H. Gelberman, J.S. Van de Berg, G.N. Lundborg, and W.H. Akeson, Flexor tendon healing and restoration of the gliding surface; an ultrastructural study in dogs, J. Bone Joint Surg. 65A:70 (1983).PubMedGoogle Scholar
  19. 19.
    J.P. Hallett, and G.R. Motta, Tendon ruptures in the hand with particular reference to attrition ruptures in the carpal tunnel, The Hand 14:283 (1982).PubMedCrossRefGoogle Scholar
  20. 20.
    E.H. Harris, L.B. Walker, and R.B. Bennett, Stress-strain studies in cadaveric human tendon and an anomaly in the Young’s modulus thereof, Med. Biol. Eng. 4:253 (1966).PubMedCrossRefGoogle Scholar
  21. 21.
    W.C. Herrick, H.B. Kingsbury, and D.Y.S. Lou, A study of the normal range of strain, strain rate and stiffness of tendon, J. Biomed. Mater. Res. 12:877 (1978).PubMedCrossRefGoogle Scholar
  22. 22.
    C.E.A. Holden, and M.D. Northmore-Ball, The strength of the profundus tendon insertion, The Hand 7:238 (1975).PubMedCrossRefGoogle Scholar
  23. 23.
    J.M. Hunter, Anatomy of flexor tendons, pulleys, vincula, synovia, and vascular structures, in: “Kaplan’s Functional and Surgical Anatomy of the Hand, 3rd edition”, M. Spinner, ed., Lippincott, Philadelphia (1984).Google Scholar
  24. 24.
    I. Kessler, and F. Nissim, Primary repair without immobilisation of flexor tendon division within the digital sheath: an experimental and clinical study, Acta Orthop. Scand. 40:587 (1969).PubMedCrossRefGoogle Scholar
  25. 25.
    L.D. Ketchum, N.L. Martin, and D.A. Kappel, Experimental evaluation of factors affecting the strength of tendon repairs, Plast. Reconst. Surg. 59:708 (1977).PubMedCrossRefGoogle Scholar
  26. 26.
    H.E. Kleinert, S. Schepel, and T. Gill, Flexor tendon injuries, Surg. Clin. N. Am. 61:267 (1981).PubMedGoogle Scholar
  27. 27.
    G.D. Lister, Incision and closure of the flexor sheath during primary tendon repair, The Hand 15:123 (1983).PubMedCrossRefGoogle Scholar
  28. 28.
    P.G. Lunn, and D.W. Lamb, “Rugby finger” — avulsion of profundus of ring finger, J. Hand Surg. 9B:69 (1984).Google Scholar
  29. 29.
    Z.B. Mashadi, and A.A. Amis, The effect of locking loops on the strength of tendon repair, J. Hand Surg. 16B:35 (1991).Google Scholar
  30. 30.
    Z.B. Mashadi, and A.A. Amis, Strength of the suture in the epitenon and within the tendon fibres: development of stronger peripheral suture technique, J. Hand Surg. 17B: 171 (1992).Google Scholar
  31. 31.
    Z.B. Mashadi, and A.A. Amis, Variation of holding strength of synthetic absorbable flexor tendon sutures with time, J. Hand Surg. 17B, 278 (1992).Google Scholar
  32. 32.
    M.L. Mason, and H.S. Allen, The rate of healing of tendons, Ann. Surg. 113:424 (1941).PubMedCrossRefGoogle Scholar
  33. 33.
    H.P. Matthews, H.J. Richards, Factors in adherance of flexor tendons after repair, J. Bone Joint Surg. 58B:230 (1976).Google Scholar
  34. 34.
    P.E. McMaster, Tendon and muscle ruptures — clinical and experimental studies of the causes and location of subcutaneous ruptures, J. Bone Joint Surg. 15:705 (1933).Google Scholar
  35. 35.
    G.A.W. Murray, and J.C. Semple, A review of work on artificial tendons, J. Biomed. Eng. 1:177 (1979).PubMedCrossRefGoogle Scholar
  36. 36.
    T.F. Nealon, Fundamental Skills in Surgery, 3rd edition, W.B. Saunders, Philadelphia (1979).Google Scholar
  37. 37.
    E.E. Peacock, Fundamental aspects of wound healing relating to the restoration of gliding function after tendon repair, Surg. Gynaec. Obstet. 119:241 (1964).Google Scholar
  38. 38.
    D.G. Pennington, The locking loop tendon suture, Plast. Reconstr. Surg. 63:648 (1979).PubMedCrossRefGoogle Scholar
  39. 39.
    A.D. Potenza, Critical evaluation of flexor tendon healing and adhesion formation within artificial digital sheaths; an experimental study, J. Bone Joint Surg. 45A:1217 (1963).PubMedGoogle Scholar
  40. 40.
    D.J. Pring, A.A. Amis, and R.R.H. Coombes, The mechanical properties of human flexor tendons in relation to artificial tendons, J. Hand Surg. 10B:331 (1985).Google Scholar
  41. 41.
    D.J. Riemersma, and H.C. Schamhardt, The cryojaw, a clamp designed for in vitro rheology studies of horse digital flexor tendon, J. Biomech. 15:619 (1982).CrossRefGoogle Scholar
  42. 42.
    N.B. Rogers, A review of the use of prosthetic materials in tendon surgery, District Columbia, Med. Ann., 39:411 (1970).Google Scholar
  43. 43.
    R. Savage, In vitro studies of a new method of flexor tendon repair, J. Hand Surg. 10B:135 (1985).Google Scholar
  44. 44.
    H. Seradge, Elongation of the repair configuration following flexor tendon repair, J. Hand Surg. 8A:182 (1983).Google Scholar
  45. 45.
    E.M. Smith, R.C. Juvinall, L.F. Bender, and J.R. Pearson, Role of the finger flexors in rheumatoid deformities of the metacarpophalangeal joints, Anhritis Rheum. 7:467 (1964).CrossRefGoogle Scholar
  46. 46.
    I. Spar, Flexor tendon ruptures in the rheumatoid hand: bilateral flexor pollicis longus rupture, Clin. Orthop. 127:186 (1977).PubMedGoogle Scholar
  47. 47.
    P.J. Stern, Multiple flexor tendon ruptures following an old anterior dislocation of the lunate; a case report, J. Bone Joint Surg. 63A:489 (1981).PubMedGoogle Scholar
  48. 48.
    H. Tkaczuk, Tensile properties of human lumbar longitudinal ligaments, Acta Orthop. Scand., Suppl. 115:5 (1968).Google Scholar
  49. 49.
    J.R. Urbaniak, J.D. Cahill, and R.A. Mortensen, An analysis of tensile strength of tendon anastomoses, J. Bone Joint Surg. 55A:884 (1973).Google Scholar
  50. 50.
    C.E. Verdan, Half century of flexor tendon surgery: current status and changing philosophies, J. Bone Joint Surg. 54A:472 (1972).PubMedGoogle Scholar
  51. 51.
    C.E. Verdan, Reparative surgery of flexor tendon in the digit, in:”Tendon Surgery in the Hand”, C.E. Verdan, ed., Churchill Livingstone, New York (1979).Google Scholar
  52. 52.
    A. Viidik, L. Sandqvist, and M. Magi, Influence of post-mortal storage on tensile strength characteristics and histology of ligaments, Acta Orthop. Scand., Suppl. 79:1 (1965).Google Scholar
  53. 53.
    P.J.F. Wade, I.F.K. Muir, and L.L. Hutcheon, Primary flexor tendon repair: the mechanical limitations of the modified Kessler technique, J. Hand Surg. 11B:71 (1986).Google Scholar
  54. 54.
    P.J.F. Wade, R.G. Wetherell, and A.A. Amis, Flexor tendon repair: significant gain in strength from the Halsted peripheral suture technique, J. Hand Surg. 14B:232 (1989).Google Scholar
  55. 55.
    P.S. Walker, and M.J. Erkman, Clinical evaluation of finger joints, in: “Human Joints and their Artificial Replacements,” P.S. Walker, Thomas, Spingfield (1977).Google Scholar
  56. 56.
    B.O. Weightman, and A.A. Amis, Finger joint force predictions related to design of joint replacements, J. Biomed. Eng. 4:197 (1982).PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1994

Authors and Affiliations

  • Andrew A. Amis
    • 1
  1. 1.Biomechanics Section, Mechanical Engineering DepartmentImperial CollegeLondonEngland

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