PMC6360319_01
Exploration showing the extensor tendon defects in zone 6-8. Note that the extensor tendons are preserved in the distal two thirds of Zone 6 and then all tendons fade into a scar in the proximal part of Zone 6 (arrow). Also note the relatively preserved skin at the zone of injury because of the nature of original injury (skin degloving without skin loss).
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In the first stage, exploration confirmed the presence of extensor tendon defects from the proximal one third of zone 6 to zone 8; including the musculotendinous junctions (Fig. 1).
insertion of the four silicone rods. Note that the rods are sutured distally; but are left free (un-sutured) proximally.
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All 4 rods were left free (un-sutured) in the distal forearm (Fig. 2). the patient resumed passive exercises of the metacarpophalangeal joints post-operatively to prevent stiffness.
Diagrammatic demonstration of the second stage. The motor tendon is the transferred flexor carpi ulnaris. The tendon graft is the flexor carpi radialis tendon which is split distally to 4 slips (one slip to each finger). The proximal tendon repair is done first. Adjustment of tension is done during the distal tendon repair between the slips of the tendon graft and the remnants of the extensor tendons.
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The second stage was done five months later (Fig. 3). The proximal tendon repair was done first between the transferred flexor carpi ulnaris tendon and the tendon graft using multiple figure-of-eight 3/0 polypropylene sutures. Each slip was then weaved through the corresponding remnant of the extensor tendon; and suturing was done using 4/0 polypropylene sutures (Fig. 3).
functional outcome at 1 year: Full active wrist extension/ finger flexion was maintained (as pre-operatively). Note the scars in the forearm from the tendon transfer and the harvesting of the tendon graft.
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At final follow up (1 year later), full active wrist extension/ finger flexion was maintained (Fig. 4).
functional outcome at 1 year: Full active finger extension with simultaneous mild wrist flexion.
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Full active extension of the fingers at the metacarpophalangeal joints was demonstrated with slight wrist flexion (Fig. 5).
the only deficit noted at 1 year: Limitation of active wrist flexion attributed to harvesting of both wrist flexors.
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As expected, active wrist flexion was limited to 20  because of the harvesting of the both wrist flexors (Fig. 6).