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Page 10 of 25 Bertolini et al. Plast Aesthet Res 2023;10:34 https://dx.doi.org/10.20517/2347-9264.2022.121

The single-stage reconstruction is the result of all the attempts made to reduce the number of surgical
[81]
procedures and the time of recovery . Furthermore, some authors stated that the use of vascularized
tendon grafts leads to faster recovery and reduces adhesion formation, because the tendons are transferred
with their vascularity and their surrounding tissue containing the tendon sheath [66,81] .

However, due to the considerable donor site morbidity and the debatable actual advantages of a
vascularized tendon graft, less-invasive techniques are recommended. Therefore, it is preferable to opt for a
thin free flap allowing for sufficient gliding in combination with an avascularized tendon graft .
[59]

Another reconstructive option to overcome extensor tendon defects is tendon allograft. Some authors found
that allograft is a safe procedure and its outcomes are very similar to those related to tendon autograft [59,83] .

Tendon transfer is an option to substitute the function of injured tendon when reconstruction is not
possible (e.g., large extensor gaps, such as those resulting from severe forearm trauma, or extensor muscle
paralysis from a radial nerve injury) [79,84-86] . This technique plays a key role even in the reconstruction of
extensor pollicis longus (EPL) tendon, both after subcutaneous injuries and large loss of tendon
substance . In order to achieve satisfactory outcomes, a tendon transfer must respect several principles:
[72]

● the donor muscle must be able to sufficiently move the recipient tendon;

● the recipient and donor muscles’ tendon degree of excursions must be comparable;

[72]
● the donor muscles must work in phase with the recipient one .

Any of these various surgical techniques could be employed in restoring the extensor tendon system, with
different indications according to Verdan’s zone of injury [59,72,87] .

Zone 1
An extensor tendon gap in zone 1 can develop both after a traumatic injury and after a chronic mallet finger
repair with the removal of scar tissue [59,86] . Based on the size of the tendon defect, different reconstruction
techniques might be chosen [59,88] .

Regarding local tendon flaps, the terminal tendon hemilateral band technique might be useful to address
tendon gaps of about 1 centimeter. This procedure uses the lateral bands of the injured finger to bridge the
extensor tendon gap and reconstruct a new terminal slip. Particularly, after wound exploration and tendon
gap measurement, L-shaped cuts are performed in the lateral bands in accordance with the size of the
defect. The cut bands are then flipped over to the distal portion of the gap and both the distal and proximal
[89]
portions of the bands are sutured . This procedure may require temporary arthrodesis of distal
interphalangeal (DIP) joints for 4-6 weeks [59,89] . Attention must be paid to leaving an adequate amount of
[89]
lateral band to prevent loss of intrinsic activity .

Interposition tendon grafting necessitates tendon harvesting to reconstruct the extensor defect and provides
the repair of tendon gaps over 1 centimeter. Palmaris longus (PL) tendon is the most commonly employed
in zone 1 reconstruction [59,63] . Various techniques have been described to provide the attachment of the
harvested tendon to the distal phalanx, including the possibility of creating a drill hole in the distal phalanx,
[90]
in which the surgeon can insert the PL tendon and secure it with a knot . The interposition of a tendon
graft requires postoperatively immobilization (usually 4 weeks) .
[91]