Mateusz Gładysz FESSH prep

FESSH prep Tendon injuries Core suture strands and locking, gap formation, pulley venting, complications after repair, wide awake repair with intraoperative active movement

Zone II flexor tendon repair: biomechanics and early active motion

Last reviewed v1.0

FESSH-040Tendon injuries●●● advanced

Regarding primary flexor tendon repair in zone II:

  1. 1.Increasing the number of core suture strands proportionally increases both the fatigue strength of the repair and its resistance to gap formation under cyclic loading.

  2. 2.In Gelberman's canine model, a repair-site gap greater than 3 mm increased adhesion formation and reduced digital range of motion.

  3. 3.Complete venting of the A4 pulley, and partial venting of the A2 pulley over no more than about 1.5–2 cm, has not been associated with clinically significant bowstringing provided the remaining pulleys are intact.

  4. 4.In Dy's meta-analysis of complications after flexor tendon repair, pooled rates were about 4 per cent for rupture, 4 per cent for adhesions and 6 per cent for reoperation, and an epitendinous suture reduced reoperation but did not influence rupture.

  5. 5.Wide-awake repair under local anaesthetic with adrenaline and no tourniquet allows an intraoperative total active movement examination that can reveal gapping caused by a loosely tied core suture, and in Higgins and Lalonde's series the tendon rupture rate was about 3 per cent.

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Question ID
FESSH-040
First published
Last reviewed
Version
v1.0
Answer key and explanations — open after answering

  1. 1. Increasing the number of core suture strands proportionally increases both the fatigue strength of the repair and its resistance to gap formation under cyclic loading.

    False

    Barrie's cadaveric cyclic-loading study found that an increase in the number of strands significantly increases the fatigue strength of a repair but does not alter its resistance to gapping, and that there was no association between gap resistance and fatigue strength; locking of the repair is what adds gap resistance at the low cyclic loads of an early active motion protocol. In the in-situ comparison, six-strand repairs were stronger than four-strand and four-strand stronger than two-strand, and adding a second Kessler loop increased strength without improving gap resistance. Strand number and locking configuration therefore address different properties.

    • Barrie KA, Tomak SL, Cholewicki J, Wolfe SW. The role of multiple strands and locking sutures on gap formation of flexor tendon repairs during cyclical loading. J Hand Surg Am. 2000;25(4):714-20. PMID 10913213
    • Barrie KA, Wolfe SW, Shean C, Shenbagamurthi D, Slade JF, Panjabi MM. A biomechanical comparison of multistrand flexor tendon repairs using an in situ testing model. J Hand Surg Am. 2000;25(3):499-506. PMID 10811755

  2. 2. In Gelberman's canine model, a repair-site gap greater than 3 mm increased adhesion formation and reduced digital range of motion.

    False

    In the in-vivo canine study a gap of more than three millimetres at the repair site did not increase the prevalence of adhesions or impair the range of motion, but it did prevent the accrual of strength and stiffness that normally occurs with time: tendons with gaps of 3 mm or less failed at a 90% higher force and were 320% more rigid at 42 days than at 10 days. The clinical importance of the 3 mm threshold is therefore that a gapped repair fails to gain strength during rehabilitation and remains vulnerable to rupture, not that it causes adhesions.

    • Gelberman RH, Boyer MI, Brodt MD, Winters SC, Silva MJ. The effect of gap formation at the repair site on the strength and excursion of intrasynovial flexor tendons. An experimental study on the early stages of tendon-healing in dogs. J Bone Joint Surg Am. 1999;81(7):975-82. PMID 10428129

  3. 3. Complete venting of the A4 pulley, and partial venting of the A2 pulley over no more than about 1.5–2 cm, has not been associated with clinically significant bowstringing provided the remaining pulleys are intact.

    True

    Tang's 2018 review states that the A2 pulley can be vented partially with an incision over its distal or proximal sheath no longer than 1.5 to 2 cm and that the A4 pulley can be vented entirely, without observed adverse effects on hand function after judicious venting; his 2014 report conditions complete A4 release on an intact A3 pulley and venting confined to the middle half of the middle phalanx. Kwai Ben and Elliot needed to vent one pulley in 64% of 126 distal zone 2 repairs, and Moriya released the entire A2 (with C1 in two fingers) in seven fingers without clinical bowstringing. Venting allows the repair to glide freely and is preferable to a tight repair that catches on the pulley edge.

    • Tang JB. New Developments Are Improving Flexor Tendon Repair. Plast Reconstr Surg. 2018;141(6):1427-1437. PMID 29579022
    • Tang JB. Release of the A4 pulley to facilitate zone II flexor tendon repair. J Hand Surg Am. 2014;39(11):2300-7. PMID 25282719
    • Moriya K, Yoshizu T, Tsubokawa N, Narisawa H, Hara K, Maki Y. Clinical results of releasing the entire A2 pulley after flexor tendon repair in zone 2C. J Hand Surg Eur Vol. 2016;41(8):822-8. PMID 27178574
    • Kwai Ben I, Elliot D. "Venting" or partial lateral release of the A2 and A4 pulleys after repair of zone 2 flexor tendon injuries. J Hand Surg Br. 1998;23(5):649-54. PMID 9821612

  4. 4. In Dy's meta-analysis of complications after flexor tendon repair, pooled rates were about 4 per cent for rupture, 4 per cent for adhesions and 6 per cent for reoperation, and an epitendinous suture reduced reoperation but did not influence rupture.

    True

    Dy's systematic review and meta-analysis reported unadjusted pooled rates of re-operation of 6%, rupture of 4% and adhesions of 4%. Meta-regression found that neither the core suture technique nor the use of an epitendinous suture influenced rupture, but the presence of an epitendinous suture decreased re-operation by 84% and adhesion development was 57% lower with the modified Kessler technique; the authors found no definitive improvement in reported complications before and after 2000. Tang's 2018 review reports minimal or no rupture during early active motion after six-strand repair with judicious venting.

    • Dy CJ, Hernandez-Soria A, Ma Y, Roberts TR, Daluiski A. Complications after flexor tendon repair: a systematic review and meta-analysis. J Hand Surg Am. 2012;37(3):543-551.e1. PMID 22317947
    • Tang JB. New Developments Are Improving Flexor Tendon Repair. Plast Reconstr Surg. 2018;141(6):1427-1437. PMID 29579022

  5. 5. Wide-awake repair under local anaesthetic with adrenaline and no tourniquet allows an intraoperative total active movement examination that can reveal gapping caused by a loosely tied core suture, and in Higgins and Lalonde's series the tendon rupture rate was about 3 per cent.

    True

    Higgins and Lalonde reported that wide-awake repair in tourniquet-free, unsedated patients permits an intraoperative total active movement examination (iTAMe) of the fresh repair, which revealed bunching and gap formation with active movement in seven of 102 patients when the core suture had been tied too loosely; all seven repairs were redone and none ruptured. Of 122 tendons in 68 patients with known outcomes, four tendons ruptured (3.3%) in three patients, all after reported accidental forced loading. This observation does not establish an exclusive cause of rupture. Tang's 2018 review describes the digital extension–flexion test as increasingly routine and notes that a wide-awake setting allows the patient to move the digits actively during surgery.

    • Higgins A, Lalonde DH, Bell M, McKee D, Lalonde JF. Avoiding flexor tendon repair rupture with intraoperative total active movement examination. Plast Reconstr Surg. 2010;126(3):941-945. PMID 20463621
    • Tang JB. New Developments Are Improving Flexor Tendon Repair. Plast Reconstr Surg. 2018;141(6):1427-1437. PMID 29579022