PMC6457017_01
Preoperative macroscopic findings: (a) Injury scar immediately proximal to
the metatarsophalangeal joint (arrow), (b) distal and proximal extensor
hallucis longus stumps (arrow heads) and (c) insufficient extension of
metatarsophalangeal and interphalangeal joints of the hallux.
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An EHL tendon rupture was suspected (Figure 1).
Preoperative magnetic resonance imaging (MRI) findings. Sagittal T2-weighted
MRI revealed the loosening of the extensor hallucis longus tendon (arrow).
Extensor hallucis capsularis was not evaluated in the forefoot and midfoot
areas because of inappropriate MRI scan area.
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Magnetic resonance imaging (MRI) revealed the loosening of the EHL tendon (Figure 2).
Preoperative computed tomography (CT) image findings. Coronal CT images
revealed the extensor hallucis capsularis (EHC) (arrow heads) medial to the
proximal stump of the extensor hallucis longus (EHL) tendon (arrow). The
width and thickness of EHC were approximately 3 and 2 mm, respectively. The
EHC tendon separated from the EHL tendon distal to the tarsometatarsal joint
and travelled alongside. Preoperatively, this was considered the point of
divergence of the EHC and EHL, but it was the adhesion intraoperatively.
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Computed tomography (CT) images revealed the presence of an EHC tendon medial to the proximal stump of the EHL tendon (Figure 3).
Intraoperative findings: (a) The proximal and distal extensor hallucis longus
(EHL) stumps (asterisks) following the incision of the tendon sheath and the
distal part of the inferior extensor retinaculum (solid lines). The gap
between stumps was 5 cm. Thick extensor hallucis capsularis (EHC) (dotted
line) was found medial to the EHL. The extensor hallucis brevis was intact
(X). (b) Retrieved EHL (dotted line) and EHC (solid line) at the proximal
wound. EHC arising from the distal end of the EHL muscle adhered to the EHL
tendon (asterisk). (c) EHC (solid line) was resected from its origin and
turned down at the point of adhesion to EHL (dotted line). (d) A
double-bundle EHC autograft was sutured to the distal EHL stump in an
interlacing manner. The double-bundle graft of EHC was slightly thinner than
that of EHL; however, if we used a turn-down reconstruction of EHL, it must
have been thinner than the double-bundle graft. Schematic diagram shows the
design of the double-bundle EHC autograft for EHL reconstruction. (e) The
first metatarsophalangeal and interphalangeal joints were slightly flexed at
ankle dorsiflexion and slightly extended at ankle plantarflexion following
suturing.
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The gap between the stumps was 5 cm at that time (Figure 4(a)). The EHL tendon was pulled distally in the proximal wound, which revealed that the EHC arose from the distal end of the EHL muscle and adhered to the EHL tendon under the portion of the inferior retinaculum (Figure 4(b)). Therefore, it was resected from its origin and turned down at the point of adhesion to the EHL (Figure 4(c)). Thereafter, the EHC was sutured alongside as a double-bundle autograft (Figure 4(d)). The sutures were carefully placed in a manner that the first MTP and interphalangeal (IP) joints were slightly flexed at ankle dorsiflexion and slightly extended at ankle plantarflexion (Figure 4(e)).
Postoperative macroscopic findings. The active range of dorsiflexion of the
hallux 1 year after surgery.
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ROM was slightly decreased (Figure 5).