TREATMENT
- Neuromodulatory medications and transcutaneous
electrical nerve stimulation(TENS), biomechanical
interventions to reduce neural tension, dorsiflexion
support, and change in running style to avoid exces-
sive varus/recurvatum knee moments. If recovery is
prolonged, MRI evaluation may be indicated (Leach,
Purnell, and Saito, 1987).
SUPERFICIAL PERONEAL NERVE
DEFINITION
- SPN entrapment typically occurs as the nerve pene-
trates the crural fascia above the ankle.
ANATOMY, PATHOPHYSIOLOGY, ANDRISKFACTORS
- SPN injury at the site of emergence from the lateral
compartment may result from sharp fascial edges,
chronic ankle sprains (25% of athletes have a history of
trauma), muscular herniation, direct contusive trauma,
fibular fracture, edema, varicose veins, wearing tight
ski boots or roller blades, biomechanical factors
(see CPN entrapment, above), and space-occupying
lesions such as nerve sheath tumors, lipomas, and
ganglia. - Up to 10% of affected individuals may have chronic
lateral compartment syndrome.
•Tight footwear may externally compress the SPN or
either of its two terminal branches.
SYMPTOMS ANDSIGNS
- Diffuse ache over the dorsolateral foot and less com-
monly numbness or tingling over the same areas
(Schon and Baxter, 1990). - Examination may reveal percussion tenderness, a fas-
cial defect (60% of patients), or muscular herniation
at the exit site approximately 10–13 cm above the
ankle. Provocative testing before and after exercise is
the most useful clinical indicator of SPN entrapment
and includes ( 1 ) pressure over the exit site during
resisted ankle dorsiflexion-eversion, ( 2 ) pressure over
the same area during passive plantarflexion combined
with inversion, and ( 3 ) percussion over the SPN
course while passive plantarflexion and inversion are
maintained. - Sensation and EDB bulk may be diminished but are
not common findings (Schon and Baxter, 1990).
DIFFERENTIALDIAGNOSIS ANDEVALUATION
- Differential diagnosis resembles that for CPN entrap-
ment. MRI can detect most mass lesions.
TREATMENT- Treatment parallels that for CPN entrapment, but may
also include corticosteroid injection at the site of
emergence from the lateral compartment, ankle insta-
bility rehabilitation, myofascial release, and use of lat-
eral wedges to decrease nerve stretch.
DEEP PERONEAL NERVE: ANTERIOR TARSAL
TUNNEL SYNDROMEDEFINITION- DPN entrapment is also called anterior tarsal tunnel
syndrome(ATTS). - DPN compression occurs in the vicinity of the exten-
sor retinaculum.
ANATOMY, PATHOPHYSIOLOGY, ANDRISKFACTORS- In the anterior leg compartment, the extensor hallucis
longus(EHL) muscle courses in a medial, oblique
direction. The DPN traverses deep to the EHL to
course between the EHL and extensor digitorum
longus(EDL) at the level of the inferior aspect of the
superior extensor retinaculum, approximately 3 to 5
cm above the ankle joint. At the level of the oblique
superior band of the inferior extensor retinaculum,
about 1 cm above the ankle joint, the DPN forms its
terminal lateral and medial branches. The lateral
branch innervates the EDB muscle. The medial
branch courses distally with the dorsalis pedis artery,
passing deep to the oblique inferior medial band of the
inferior extensor retinaculum, where it may be
entrapped by processes affecting the talonavicular
joint (Schon and Baxter, 1990). - Risk factors include trauma, shoe contact pressure
(boot top neuropathy, wearing a key under the tongue
of the shoe), osteophytic compression, edema, and
synovitis or ganglia (Smith and Dahm, 2001).
SYMPTOMS ANDSIGNS- Deep, aching, dorsal midfoot pain and neuropathic
symptoms extending into the first web space. - Percussion along the course of the DPN starting at the
fibular head may localize the entrapment. - Symptom provocation may occur with either plan-
tarflexion or dorsiflexion.
DIFFERENTIALDIAGNOSIS ANDEVALUATION- Differential diagnosis parallels that for CPN and SPN
entrapments, but also includes anterior compartment
syndrome. - EDX can assist in differential diagnosis and localiza-
tion (e.g., involvement of the EDB or CPN).
Compartment pressures and MRI may be useful.
400 SECTION 4 • MUSCULOSKELETAL PROBLEMS IN THE ATHLETE