Generally, the tibial nerve and its branches ie, the medi-al and latermedi-al plantar nerves inner-vate the intrinsic musculature, al-though the deep peroneal nerve innervates the extens
Trang 1About the Foot and Ankle
David B Thordarson, MD, and Christopher J Shean, MD
Abstract
Nerve and tendon lacerations about
the foot and ankle are relatively
com-mon Delayed repair or lack of repair
of tendons can lead to foot
deformi-ties, which may be especially
prob-lematic for a child.1Most published
reports are small case series of
spe-cific tendon injuries in which treatment
recommendations are derived from the
surgical management of pathologic
conditions of the foot and ankle
Untreated tendon lacerations of the
foot may have fewer sequelae than
un-treated lacerations of the hand; still,
it is inappropriate to equate a
normal-ly functioning, lacerated tendon of a
toe, for example, to a tenotomy done
for a pathologic condition, such as a
flexible clawtoe.2Similarly, an
insen-sate digit resulting from nerve
inju-ries in the fingers can lead to
mark-edly impaired function in fine
manipulation By comparison,
local-ized numbness in the foot caused by
a distal nerve injury may be
relative-ly innocuous, although more
proxi-mal injuries or multiple distal injuries
can lead to a greater area of insensate
skin and to impairment
Nerve Injuries
Nerve injuries of the foot are gener-ally caused by a penetrating wound
The sequelae of such injuries depend
on the nerve injured and the level of the injury In the foot and ankle, the main function of the nerves is to pro-vide sensation Generally, the tibial nerve and its branches (ie, the
medi-al and latermedi-al plantar nerves) inner-vate the intrinsic musculature, al-though the deep peroneal nerve innervates the extensor digitorum brevis and extensor hallucis brevis muscles Denervation of these motor nerves can lead to clawing of the toes because of a resulting imbalance of intrinsic and extrinsic muscles
The long-term morbidity of nerve injuries of the foot is predominantly related to sensory nerve injury, except when a tibial nerve injury causes in-trinsic muscle function loss The two main problems associated with inju-ries to these nerves are the lack of sen-sation in the distal distribution of the nerve (Fig 1) and the formation of a painful neuroma When the nerve
in-jury occurs in a weight-bearing area
of the foot, the presence of a painful neuroma often leads to complex re-gional pain syndrome type I
General Principles of Nerve Surgery
Nerve Repair and Reconstruction
The goal of nerve repair is to in-crease the number and accuracy of ax-ons that regenerate across the injury site A successful repair includes the preparation of the injured nerve stumps and accurate, atraumatic nerve approximation without undue tension The use of loupe magnification or an operating microscope is essential Epineurial repair is recommended for neurorrhaphy about the foot and
Dr Thordarson is Vice Chair, Department of Or-thopaedic Surgery, Keck School of Medicine, Uni-versity of Southern California, Los Angeles, CA.
Dr Shean is Associate Physician, Kaiser Perma-nente, Baldwin Park, CA.
None of the following authors or the departments with which they are affiliated has received anything
of value from or owns stock in a commercial com-pany or institution related directly or indirectly
to the subject of this article: Dr Thordarson and
Dr Shean.
Reprint requests: Dr Thordarson, USC Depart-ment of Orthopaedic Surgery, GNH 3900, 1200 North State Street, Los Angeles, CA 90033 Copyright 2005 by the American Academy of Orthopaedic Surgeons.
Nerve and tendon lacerations of the foot and ankle region are relatively common.
Acute nerve and tendon injuries should be repaired with appropriate techniques at
the time of initial wound exploration Primary nerve repair may help minimize the
risk of painful neuroma formation; primary tendon repair can lead to better
func-tional results than delayed repair Most chronic nerve injuries, except those to the
tibial nerve or its major divisions, are managed by resection of a painful neuroma
and burying the nerve ending in a protected area Delayed reconstruction of tendon
injuries is performed when correction of the functional deficit outweighs the
mor-bidity of surgery.
J Am Acad Orthop Surg 2005;13:186-196
Trang 2ankle (Fig 2) Epineurial repair is
sim-pler than group fascicular repair, and
it avoids the increased scarring and
damage to intraneural elements
caused by the additional dissection
required by group fascicular repair
Except for the tibial nerve, group
fas-cicular repair is not possible because
the nerves are pure sensory and do
not have multiple fascicles In our
ex-perience, protective sensation has
been achieved with epineurial repair
of acute tibial, medial, and lateral
plantar nerves in the foot
If repair of a transected tibial nerve
cannot be achieved without undue tension, then reconstruction using a simple cable graft with a reversed sural nerve autograft is indicated Be-cause of the morbidity of the sural nerve graft, delayed reconstruction of the other nerves of the foot and an-kle is not justified Favorable out-comes can be achieved with this tech-nique; success appears to be related
to required nerve graft length Hat-trup and Wood3reported that
short-er nshort-erve grafts yielded bettshort-er results than long grafts when done an aver-age of 10 months after injury Five of
seven patients with nerve grafts≤6
cm had a good result, whereas the five grafts >6 cm had no good results
Neuroma Formation and Prevention
The pathogenesis of neuroma for-mation consists of an injury to the en-doneurium permitting regenerating axons to escape into the surrounding tissue in a haphazard manner Nerve repair and interpositional nerve graft-ing are the best ways to minimize neuroma formation, by allowing the regenerating nerve fibers to connect with the distal portion of the nerve Management of an established neu-roma of the foot and ankle begins with nonsurgical treatment Commonly used modalities are mechanical desen-sitization, transcutaneous electrical nerve stimulation, local corticosteroid injection, and medications In our ex-perience, these techniques tend to pro-vide transient, partial relief For sur-gical intervention, diagnostic nerve blocks can be used to confirm the di-agnosis of neuroma and to exclude the involvement of other nerves Although numerous surgical techniques for painful neuromas have been de-scribed, simple excision and implan-tation of the proximal nerve stump
in a nonirritable location remains the treatment of choice
Treatment Recommendations for Nerve Injury
Most nerve injuries to the foot should
be treated with acute epineurial re-pair, followed by primary wound clo-sure If the injury requires surgical débridement, nerve repair usually adds little morbidity to the procedure
In addition to minimizing the risk of subsequent sensory deficit and the development of claw toes, nerve re-pair also may decrease the incidence
of painful neuroma If the distal nerve end cannot be identified or if a gap exists that precludes tension-free
re-Figure 1 Dorsal (A) and plantar (B) aspects of the foot showing cutaneous innervation
Mi-nor variability between the areas supplied by each nerve is frequently present 1 = sural nerve,
2 = superficial peroneal nerve branches, 3 = saphenous nerve, 4 = deep peroneal nerve, 5 =
medial plantar nerve, 6 = lateral plantar nerve, 7 = medial calcaneal nerve (Adapted with
permission from Sarrafian SK: Nerves, in Foot and Ankle: Descriptive, Topographical, and
Func-tional, ed 2 Philadelphia, PA: JB Lippincott, 1993, p 370.)
Trang 3pair, then the proximal nerve stump
is buried in soft tissue, as with a
neu-roma excision Lesions distal to the
arch or in the distal forefoot
gener-ally are not repaired because of the
small size of the nerve and the
min-imal sensory deficit
If the nerve injury is the result of
a puncture wound, and if surgical
treatment of the wound is
unneces-sary, then the morbidity of surgery
must be considered In cases of gross
wound contamination, a delayed
pri-mary nerve repair can be performed
after the wound has been
adequate-ly débrided Postoperativeadequate-ly, the foot
and ankle are immobilized for 3 weeks
to protect the nerve repairs until they
can tolerate mild traction An
associ-ated tendon repair frequently results
in a longer period of protection
Often patients present with a nerve
injury to the plantar aspect of the foot
after the wound was cleansed and
su-tured in an emergency department;
the underlying nerve injury was not
identified or treated In these
situa-tions, treatment decisions are based
on balancing the risks and benefits of
surgery because nerve grafting is
of-ten required to reestablish nerve
con-tinuity
Tibial Nerve and Its Branches
The tibial nerve provides the plan-tar sensation to the entire foot At the proximal aspect of the flexor retinac-ulum of the ankle, the calcaneal branches divide from the tibial nerve and course along the medial aspect
of the heel to provide sensation to the
heel pad (Fig 3) At approximately the level of the medial malleolus, the tibial nerve bifurcates into the
medi-al and latermedi-al plantar nerves The me-dial plantar nerve provides sensation
to the medial portion of the arch and
to the medial three and a half digits The lateral plantar nerve provides sensation to the lateral arch and to one and a half digits Additionally, the medial plantar nerve provides inner-vation to the abductor hallucis,
flex-or hallucis brevis, flexflex-or digitflex-orum brevis, and first lumbrical muscles The lateral plantar nerve innervates the quadratus plantae, interossei, ad-ductor hallucis, abad-ductor digiti min-imi, and second through fourth lum-brical muscles The medial and lateral plantar nerves divide into common digital nerves in the midarch and, at the base of each web space, split into the proper digital nerves supplying sensation to one half of each adjacent toe of a given web space
A tibial nerve injury that leads to denervation of the entire plantar as-pect of the foot or the majority of the plantar aspect of the foot is poorly tol-erated The nerve injury should be
ex-Figure 2 Epineurial repair Note that only epineurial sutures are placed, with no group
fas-cicular repair (deep sutures) performed (Adapted with permission from Wiglis EFS: Nerve
repair and grafting, in Green DP [ed]: Operative Hand Surgery, ed 2 Philadelphia, PA: Churchill
Livingstone, 1988, p 1381.)
Figure 3 Medial view of the ankle showing the tibial nerve dividing into the medial and lateral plantar nerves, with the medial calcaneal branches evident (Adapted with
permis-sion from Sarrafian SK: Nerves, in Foot and Ankle: Descriptive, Topographical, and Functional,
ed 2 Philadelphia, PA: JB Lippincott, 1993, p 384.)
Trang 4plored and repaired Nunley and
Ga-bel4reported on five patients treated
with sural nerve grafting of tibial
nerve injuries Results were
evaluat-ed by the return of superficial
sensa-tion, healing of plantar ulcerasensa-tion,
and absence of neurogenic pain The
authors noted that ultimate recovery
might require up to 4 years Dellon
and Mackinnon5reported successful
results in all eight patients with
tib-ial nerve deficits They concluded that
grafting the tibial nerve can restore
at least some sensibility to the
plan-tar foot Hattrup and Wood3used an
interfascicular grafting technique for
delayed neural reconstruction in three
cases of tibial nerve grafts; they
re-ported one good, one fair, and one
poor result
Transection of the calcaneal
branch-es leads to localized numbnbranch-ess of the
heel pad Most patients tolerate this
well if the sensation of the plantar
fore-foot remains intact However,
lacer-ations of the calcaneal branches
fre-quently occur immediately adjacent
to the weight-bearing surface of the
foot; these lacerations may lead to
painful neuromas Kim and Dellon6
reported on a series of 15 patients with
heel pain resulting from calcaneal
neu-romas They recommended using an
extended tarsal tunnel incision to
per-mit identification of all calcaneal
nerves and nerve implantation into
the flexor hallucis longus muscle
af-ter neuroma resection This approach
yielded good or excellent results in
14 of 15 patients Reflex sympathetic
dystrophy can occur after transection
of calcaneal branches along the
me-dial aspect of the heel Because the
sen-sory deficit is well tolerated,
transect-ing the involved branch closer to its
split from the tibial nerve results in
the same sensory deficit but removes
the painful neuroma from the
weight-bearing aspect of the foot
Transection of the medial or
later-al plantar nerve in the proximlater-al
por-tion of the arch leads to a bothersome
area of numbness in the plantar
as-pect of the foot, with the patient
los-ing all protective sensation supplied
by the injured nerve in the distal re-gion of the foot Isolated laceration of the lateral plantar nerve is better tol-erated If sensation is present in half the foot distally, options include sim-ply cutting the neuroma back to a less painful area or performing a nerve re-pair, which usually requires harvest-ing a sural nerve graft In most cases, nerve repair has led to recovery of protective sensation of the isolated portion of the foot
Digital Nerves
Injury to a single common digital nerve in the distal forefoot is gener-ally well tolerated because it is the traumatic equivalent of excising a Morton neuroma In one study of in-juries to the flexor hallucis longus ten-don, four patients underwent associ-ated primary repair of lacerassoci-ated nerves (three proper digital nerves, one medial plantar nerve).7Normal sensation was achieved in only one patient after repair of the proper dig-ital nerve The sensory deficit in the other three patients had little effect on total function, although the nerve in-juries were associated with a hyper-sensitive scar In another study focus-ing on tendon injuries, digital nerves were noted to be lacerated in six pa-tients and were repaired in three.2 Mild, decreased pin-prick sensation was noted in all six, but no patient reported symptomatic numbness
If the transection occurs in a weight-bearing area, typically the only treatment required is transection
of the nerve branch at a more prox-imal level and burying it in the arch musculature Johnson et al8reported
on 33 feet in which a longitudinal plantar incision was used to excise a stump neuroma after excision of a Morton neuroma The proximal end
of the nerve was allowed to retract into the more proximal arch Twenty-two patients (67%) had complete re-lief or marked improvement in their pain; three (9%) had improvement with persistent pain Eight patients
(24%) had no improvement or worse pain at an average of 67 months af-ter surgery Wolfort and Dellon9 per-formed a prospective study of 17 re-current interdigital neuromas resected through a plantar incision with im-plantation of the proximal end of the nerve into an intrinsic muscle in the arch of the foot At a mean follow-up
of 34 months, 10 of 13 patients had excellent relief and had returned to their regular jobs Twenty percent had good relief of symptoms but had gone
to work at different jobs than previ-ously held and had had to change their shoe wear
Superficial Peroneal Nerve
The superficial peroneal nerve ex-its the deep fascia in the distal lateral aspect of the leg and forms two branches that supply sensation to most of the dorsal aspect of the foot (Figs 1 and 4) The lateral of these two branches becomes the dorsal interme-diate cutaneous nerve; it supplies sen-sation to most of the dorsal and mid-portion of the foot as well as to the third and sometimes fourth web space The medial branch becomes the dorsal medial cutaneous branch;
it supplies sensation to the medial dorsal aspect of the foot as well as to the medial aspect of the great toe and the second web, although there is some variability between the exact ar-eas of innervation Acute manage-ment of a laceration of the superficial peroneal nerve branch should include nerve exploration and epineurial re-pair if the two ends can be identified The management of a subacute in-jury to the superficial peroneal nerve depends on the level of pain and on the degree of sensory deficit Numb-ness on the dorsal aspect of the foot usually is well tolerated; in most
cas-es, delayed repair is not warranted However, nerve injuries at the ankle level frequently lead to a neuroma that is irritated by shoe wear or an-kle movement Transecting the nerve above the ankle and burying it in the anterior compartment musculature
Trang 5provides adequate symptomatic
re-lief from irritation from shoe wear or
motion of the ankle
Deep Peroneal Nerve
The deep peroneal nerve supplies
sensation to the first dorsal web
space (Figs 1 and 4) and innervation
to the extensor digitorum brevis and
extensor hallucis brevis muscles
Denervation of the extensor hallucis
brevis and extensor digitorum
brevis muscles can weaken toe
ex-tension but generally is well toler-ated The most frequent complaint after deep peroneal nerve laceration
is a painful neuroma on the dorsal aspect of the foot
In the presence of acute lacera-tions, epineurial repair minimizes the risk of a painful neuroma In a sub-acute setting or in the presence of a nerve injury with segmental loss or inability to identify the two ends, transecting the nerve proximal to the ankle and burying it in the anterior
compartment of the leg has led to good symptomatic relief
In a series of 19 dorsal foot neu-romas resulting from superficial or deep peroneal nerve injuries in 11 pa-tients,10treatment included resection
of the neuroma with implantation of the nerves into the anterolateral com-partment Excellent results were re-ported for 9 of 11 patients after an av-erage of 29 months The authors recommended anterolateral compart-ment fasciotomy to avoid potential problems since the anterolateral com-partment muscles, shrunken by dis-use, regain normal size as pain re-solves
Saphenous Nerve
The saphenous nerve is a small cu-taneous nerve branch that follows the saphenous vein along the anterome-dial aspect of the ankle Generally, an injury results in a small area of de-creased sensation over the medial border of the hindfoot, and occasion-ally into the medial midfoot, which
is well tolerated Acute epineurial repair is difficult because the nerve
is small A painful neuroma should
be treated with nerve transection proximal to the ankle joint and bur-ied in an adjacent muscle, such as the soleus
Sural Nerve
The sural nerve is a wholly
senso-ry nerve providing sensation to the lateral border of the foot Numbness
in its area of distribution generally is well tolerated; thus, the nerve fre-quently is harvested for nerve graft-ing elsewhere in the body If a sural nerve injury is identified in an acute traumatic wound, epineurial repair may decrease the incidence of a pain-ful neuroma Alternatively, an acute injury may be treated with the same methods as those for delayed treat-ment: transection of the nerve 5 to 7
cm proximal to the ankle to minimize pressure over the neuroma from shoe wear or irritation from motion of the ankle
Figure 4 The dorsal cutaneous nerves of the foot The branches of these nerves correspond
to the areas of innervation (Fig 1), but some minor variability in their distribution frequently
is present (Adapted with permission from Sarrafian SK: Cross-sectional and topographic
anat-omy, in Foot and Ankle: Descriptive, Topographical, and Functional, ed 2 Philadelphia, PA: JB
Lippincott, 1993, p 419.)
Trang 6Tendon Lacerations
Acute tendon lacerations about the
foot and ankle most commonly are
caused by penetration of the plantar
aspect of the foot by a sharp object
or by a sharp object dropped onto the
dorsum Most of these wounds are
clean, with limited contamination
Treatment of the tendon injury
de-pends on whether it is identified
acutely or after a delay In the acute
setting, standard wound
manage-ment should be used, including
ap-propriate tetanus prophylaxis and
débridement of any devitalized tis-sue Motor strength of underlying tendinous structures should be as-sessed to define whether a tendon in-jury has occurred (Figs 5 and 6)
Achilles Tendon
The gastrocnemius and soleus muscles function, through the Achil-les tendon, as the major ankle pltar flexors and stabilizers of the an-kle joint The maximum excursion of the Achilles tendon is approximately
4 cm; thus, lacerations of this tendon tend to retract 4 cm or more.11
An acute laceration of the Achil-les tendon should be relatively eas-ily identifiable following penetra-tion of the posterior aspect of the ankle region (Fig 5, A) Despite con-troversy regarding surgical versus nonsurgical treatment of an acute Achilles tendon rupture, an acute tendon laceration should be re-paired surgically since the patient requires a surgical procedure to re-pair the skin laceration Many su-ture techniques have been de-scribed; one preference for an acute repair is to use a Krackow suture12
Figure 5 A,The lateral aspect of the ankle showing the posterior position of the Achilles tendon and location of peroneal tendons as they
course along the posterior and inferior aspects of the fibula to their respective insertions B, The dorsal aspect of the foot and ankle showing the course of the extensor tendons and the tibialis anterior tendon C, The medial aspect of the ankle showing the relationship of the tibialis
posterior, flexor digitorum longus, and flexor hallucis longus tendons (Panel A adapted with permission from Netter FH: Muscles of leg:
Lateral view, in Colacino S [ed]: Atlas of the Human Body Summit, NJ: CIBA-GEIGY, 1989 Panel B adapted with permission from Sarrafian SK: Cross-sectional and topographic anatomy, in Foot and Ankle: Descriptive, Topographical, and Functional, ed 2 Philadelphia, PA: JB Lip-pincott, 1993, p 423 Panel C adapted with permission from Netter FH: Tendon sheaths of ankle, in Colacino S [ed]: Atlas of the Human Body.
Summit, NJ: CIBA-GEIGY, 1989.)
Trang 7with a no 2 nonabsorbable braided
suture (Fig 7) If the laceration is
di-rectly off bone, additional
supple-mentation with suture anchors to
the posterior calcaneus may be
ad-vantageous Wickes et al1noted that,
in a series of 21 Achilles tendon
lac-erations in children, results were
generally good with earlier repair
Delayed treatment of the Achilles
laceration may require an Achilles
tendon reconstruction procedure
be-cause the proximal muscle-tendon
unit will retract, leading to a large gap
of scar tissue If more than 6 weeks have passed since the injury, Achil-les reconstruction with either turn-down flaps or V-Y advancement of gastrocnemius fascia, or a flexor hal-lucis longus muscle augmentation, frequently is necessary.13
Tibialis Anterior Tendon
The tibialis anterior tendon (Fig 5, C) functions eccentrically after heel strike to control acceleration of the
foot and concentrically, contracting after toe-off, to assist in foot clearance during the swing phase of gait It pro-vides approximately 80% of the dor-siflexion power of the ankle.14Loss
of function can result in a slapping gait upon heel strike and a tendency toward tripping during the swing phase of gait, or in a steppage gait in which the hip is flexed more than nor-mal during the swing phase to pre-vent catching the toes of a nondorsi-flexed foot A tender, bulbous mass proximal to the laceration is
frequent-ly palpable at the level of tendon re-traction Patients have weak dorsi-flexion and no palpable tension of the tibialis anterior tendon along the an-terior aspect of the ankle with dorsi-flexion of the ankle
Treatment of acute laceration should include end-to-end repair.2,12,15-17 Pri-mary repair is possible a minimum
of 6 weeks after injury and should
be attempted for up to 3 months af-ter injury The distal end of the lac-eration is usually found in the
re-Figure 6 Plantar aspect of the foot showing the course of the flexor digitorum longus and
flexor hallucis longus tendons (Adapted with permission from Netter FH: Muscles of the
sole of the foot: Second layer, in Colacino S [ed]: Atlas of the Human Body Summit, NJ:
CIBA-GEIGY, 1989.)
Figure 7 The Krackow stitch (Adapted with permission from Armagan O, Shereff MJ: Ten-don and injury repair, in Myerson M [ed]:
Foot and Ankle Disorders Philadelphia, PA: WB
Saunders, 2000, p 945.)
Trang 8gion of the skin laceration The
proximal end can retract 3 cm or
more It should be possible to place
a hemostat beneath the extensor
ret-inaculum to pull the lacerated
ten-don into the wound Nonabsorbable
sutures then can be woven through
the tendon using a Kessler, Bunnell,
or Krackow suture technique If the
tendon is frayed, an additional
small-er monofilament suture can be used
to oversew the tendon ends, creating
a smoother surface and increasing the
strength of the repair.18
In cases of delayed identification,
especially more than 3 months after
injury, it is often impossible to
pri-marily repair the two ends of the
tib-ialis anterior tendon A
dorsiflexion-assist ankle-foot orthosis is acceptable
nonsurgical treatment in elderly
pa-tients or those with low functional
de-mand Surgical treatment consists of
either a sliding tendon graft or an
ad-jacent tendon transfer (eg, extensor
hallucis longus) to span the gap12(Fig
8) A sliding tendon graft involves
harvesting half the width of the
ten-don proximally and turning this
down to span any remaining gap in
the tibialis anterior tendon The repair
can be augmented by anchoring the
tibialis anterior tendon to the medial
aspect of the foot into the medial
cu-neiform or dorsal navicular distal to
the extensor retinaculum No marked
weakness has been noted with this
method The new insertion is distal
to the extensor retinaculum, which
acts as a pulley for the tibialis
an-terior tendon Postoperatively,
pa-tients should be kept in a short leg,
nonwalking cast for 4 weeks,
fol-lowed by 2 to 4 weeks in a walking
cast or boot
Floyd et al2reported on three
chil-dren who underwent repair of a
tib-ialis anterior tendon; all regained
good function Simonet and Sim16
noted excellent results in four of five
tibialis anterior tendon laceration
re-pairs In an earlier publication, good
results were reported with open
re-pair of the tibialis anterior tendon
acutely following laceration.15Five of eight patients had a good outcome;
two had a poor outcome and one, a fair outcome, but these three patients had multiple tendon lacerations Grif-fiths17noted unsatisfactory results in untreated laceration of the peroneal, tibialis posterior, and tibialis
anteri-or tendons
Peroneal Tendons
The peroneus brevis tendon is the major everter of the foot; the peroneus longus serves as an accessory everter and also as a plantar flexor of the first metatarsal (Fig 5, A) Acute lacera-tion of the peroneal tendons should
be repaired as part of the repair of the
skin laceration Weakness of either or both of these tendons can lead to an inversion deformity of the foot.1,17It may be difficult to differentiate be-tween the tendons if both are lacer-ated at the level of the lateral malle-olus The peroneus brevis muscle has
a lower lying muscle belly and is an-terior to the peroneus longus at the level of the lateral malleolus
Distal-ly, the peroneus longus tendon can be identified by placing gentle traction
on the tendon and palpating plantar flexion of the first metatarsal Repair
of these tendons is similar to that of the tibialis anterior tendon Lacera-tions of the superior peroneal retinac-ulum also should be repaired at the
Figure 8 Extensor hallucis longus transfer for chronic, irreparable tibialis anterior tendon laceration Note that the distal extensor hallucis longus stump is tenodesed to the extensor hallucis brevis, while proximally the extensor hallucis longus is used as tendon graft ma-terial to repair the distal stump of the tibialis anterior tendon The proximal tibialis anterior tendon is placed under tension at time of repair (Adapted with permission from Armagan
O, Shereff MJ: Tendon and injury repair, in Myerson M [ed]: Foot and Ankle Disorders
Phil-adelphia, PA: WB Saunders, 2000, p 950.)
Trang 9same time to prevent peroneal tendon
subluxation
Delayed identification of
lacerat-ed peroneal tendons still warrants
surgical intervention when pain or
functional limitation, such as an
in-version deformity, exists In chronic
cases, especially more than 3 months
after injury, a primary repair may be
difficult A side-by-side tenodesis or
sliding graft to the adjacent peroneal
tendon may be performed to repair
any gap in the tendons Flexor
hal-lucis longus repair also has been
de-scribed.19
Tibialis Posterior Tendon
The primary function of the
tibi-alis posterior tendon (Fig 5, C) is
pow-erful inversion of the heel It is most
active during the heel rise portion of
gait, when it locks the hindfoot in
varus to stabilize the foot for the
toe-off portion of the gait cycle An acute
laceration of this tendon should be
re-paired.20A flatfoot deformity has been
noted in patients with untreated acute
lacerations of the tibialis posterior
ten-don, resulting from loss of hindfoot
inversion and the unopposed pull of
the peroneus brevis tendon.21
Identification of a tibialis
posteri-or tendon laceration may not occur
for months after injury Primary
re-pair is impossible, and a secondary
flexible flatfoot deformity may have
developed In such cases, a flexor
dig-itorum longus tendon may be used
for reconstruction, similar to using a
tibialis posterior tendon
advance-ment for repair of an attritional
rup-ture A calcaneal osteotomy may be
considered if a secondary flexible
flat-foot deformity has developed If there
is a fixed flatfoot deformity,
appropri-ate nonsurgical treatment (eg, an
ac-commodative orthotic) is indicated
Acute repair of a tibialis posterior
tendon laceration can lead to a good
result, as demonstrated by Floyd et
al.2One patient had a good result
af-ter repair, whereas the second patient
had a planovalgus foot deformity that
developed in the 5 years following an
untreated laceration Goldner et al21 reported on three patients with un-treated acute lacerations; all
report-ed weakness of the foot and subse-quent loss of the arch with increased physical activity
Flexor Hallucis Longus Tendon
The function of the flexor hallucis longus tendon (Figs 5, C and 6) is plantar flexion of the great toe inter-phalangeal joint; it also serves as a dy-namic stabilizer of the metatarsopha-langeal joint Lacerations therefore lead
to decreased great toe flexion strength
This may be less pronounced if the laceration is proximal to the knot of Henry because significant interconnec-tions between the flexor hallucis lon-gus and flexor digitorum lonlon-gus ten-dons are usually present
When possible, primary surgical re-pair of a lacerated flexor hallucis lon-gus tendon should be attempted acutely Great care should be taken not
to overtighten the flexor hallucis lon-gus; doing so can result in a claw toe deformity from excessive tension In cases of delayed identification with weakness of great toe flexion, marked retraction of the flexor hallucis lon-gus may be present; thus, a primary repair is not possible Tenodesis of the flexor hallucis longus to the flexor hal-lucis brevis near the metatarsopha-langeal joint may be used.7However, little morbidity has been reported with flexor hallucis longus transfer for re-pair of chronic ruptures of the Achil-les tendon In this case, the flexor hal-lucis longus is transected above the point where decussations of flexor hal-lucis longus to flexor digitorum lon-gus fiber are usually present, at the knot of Henry.12
An untreated laceration of the
flex-or hallucis longus does not always lead to impaired function Frenette and Jackson7reported on 10 patients identified as athletic The laceration was not repaired in four patients, and none had subsequent disability How-ever, laceration of both the flexor hal-lucis longus and flexor halhal-lucis brevis
tendons was thought to impair func-tion, and repair was advocated in these cases Repair was easier when lacerations were distal to the insertion
of the flexor hallucis brevis tendon Floyd et al2reported that 10 of 13 pa-tients with lacerations of the flexor hallucis longus underwent primary repair; two others had secondary re-pair Nine of the 12 patients treated with repair had active metatarsopha-langeal joint flexion; 3 had none
Flexor Digitorum Longus Tendon
The primary function of the
flex-or digitflex-orum longus tendon (Fig 6)
is flexion of the lesser toes Laceration
of this tendon is well tolerated because
of the presence of the flexor digitorum brevis muscles; they generally prevent significant toe deformity from occur-ring after isolated laceration of the
flex-or digitflex-orum longus With a lacera-tion proximal to the quadratus plantae, some residual strength of the flexor digitorum longus may persist via this muscle The flexor digitorum longus
is commonly used as a tendon trans-fer for chronic ruptured tibialis pos-terior tendons, with minimal long-term morbidity
If, during wound exploration fol-lowing acute laceration of the foot, the flexor digitorum longus is found to
be lacerated, and if repair can be eas-ily performed, repair should be done Floyd et al2reported on five patients who underwent primary repair of the flexor digitorum longus tendon and one who had secondary repair All had good active motion of the in-volved toes without deformity De-layed repair would rarely be
indicat-ed because laceration of the tendon proximal or distal to the knot of
Hen-ry is generally well tolerated
Extensor Hallucis Longus Tendon
The main function of the extensor hallucis longus tendon (Fig 5, B) is
to extend the great toe, especially the interphalangeal joint Laceration of
Trang 10this tendon typically results in a
flexed position of the great toe, which
is generally well tolerated during
shoe wear; however, it can lead to
tripping because of weak
dorsiflex-ion in the swing phase of gait as the
toe sits in a plantarflexed position
Acute identification of a laceration
of the extensor hallucis longus tendon
requires treatment with appropriate
tendon repair techniques to prevent
deformity.2,7,18 Although the
maxi-mum excursion has been reported as
2 to 4 cm, the tendon in fact may
re-tract 5 cm or more, perhaps because
of repetitive motion of the ankle
De-layed identification, especially of
more than 3 months, usually
pre-cludes an end-to-end repair A
side-to-side tenodesis with the distal end
of the extensor hallucis longus to the
extensor hallucis brevis tendon, or to
an adjacent extensor digitorum
lon-gus tendon, may be required
A few authors have noted good
outcomes with repair of the extensor
hallucis longus tendon Floyd et al2
noted that 11 of 13 patients who
un-derwent repair of the lacerated
exten-sor hallucis longus had active
inter-phalangeal joint extension Holmes22
also noted functional impairment
with laceration of the extensor
hallu-cis longus and recommended both primary and delayed repair
Howev-er, some authors think that an unre-paired laceration of the extensor hallucis longus tendon is well toler-ated.17
Extensor Digitorum Longus
An isolated laceration of the sec-ond through fourth extensor digi-torum longus tendons (Fig 5, B) usu-ally does not cause major problems
if the extensor digitorum brevis re-mains intact An isolated laceration
of the extensor digitorum longus to the fifth toe typically results in a flexed toe deformity because of the absence of the extensor digitorum brevis tendon Acute repair of these subcutaneous tendons is easily achieved at the time of repair of a dor-sal foot laceration Delayed recogni-tion of these injuries does not require repair provided the extensor digi-torum brevis muscle is intact Other-wise, a claw toe deformity, resulting from unopposed pull of the flexor tendons, can develop, with flexion of the metatarsophalangeal, proximal interphalangeal, and distal interpha-langeal joints However, patients with significant claw toe deformity after unidentified extensor digitorum
lon-gus laceration may require a delayed repair or reconstruction with tenod-esis to the adjacent intact extensor tendon In one study, seven of eight patients noted to have extensor dig-itorum longus lacerations underwent primary repair, with minimal sub-jective complaints at follow-up.2 Wickes et al1reported that extensor digitorum longus lacerations are well tolerated because the adjacent ten-dons serve as an internal splint
Summary
Acute lacerations in the foot and an-kle region require careful physical ex-amination to identify underlying nerve and tendon injuries Acute nerve and tendon injuries identified
at the time of wound exploration should be repaired without undue tension with appropriate nerve and tendon repair techniques Early ten-don repair generally provides good results Delayed tendon repair requir-ing tendon reconstruction, tendon transfers, or osteotomies to restore normal foot function is more chal-lenging Delayed repair may be avoided with appropriate acute rec-ognition of the damaged structures
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