As a general medical officer (GMO), you will frequently be called upon to evaluate orthopedic problems. The active duty population regularly generates a large number of sports related injuries, to include foot and ankle injuries. Ankle pain can be difficult to resolve especially recurrent pain that seems to be more extensive than a simple "ankle sprain." It is important to remember that the "ankle sprain" may have aggravated a previously latent condition. Also keep in mind that gait disturbance can be caused by any painful problem or deformity in the extremity, back, hip, or knee. These sites can refer pain to the foot.

The following algorithms will help you evaluate and diagnose the painful foot and ankle by region:

• Anterior ankle

• Antero-medial / medial ankle

• Postero-medial ankle

• Postero-lateral ankle

• Lateral ankle and sinus tarsi region

• Antero-lateral ankle

• Lateral and mid foot

1. The patient is able to direct you to the painful area.

2. Most of the soft tissue inflammation has resolved / healed, (i.e. evaluation of the foot and ankle is 2-3 weeks after the initial trauma.)

3. Non-displaced avulsion fractures have healed.

Pertinent points of the evaluation

History

• Mechanism of injury

• What causes or alleviates the pain?

• Where exactly does it hurt the most?

• What activities can the patient no longer perform due to the injury?

• Was the patient able to walk or bear weight on the ankle immediately after the trauma?

Physical examination:

• Have the patient put one finger on the point of maximum tenderness.

• Evaluate the foot with the following points in mind; amount of swelling, presence of ecchymosis, note whether the foot is a planovalgus or canovalgus foot type, and note any laxity of the ankle in the A/P direction (ankle anterior drawer sign) as compared with the opposite ankle.
  

Anterior Talo-Fibular Ligament Insufficiency

• Cause: Inversion injury which has stretched the ligament followed by inadequate immobilization in the convalescent stage. This will lead to a lax, painful ligament

• History: Sprained ankle in the past. Now patient "loses balance easily" on uneven pavement.

• Findings: Laxity on anterior drawer test of ankle (compared to other ankle). Tenderness to palpation of ligament. Patient feels "unsteady" when standing on injured leg even for a short period of time.

• Tests: Stress x-ray views of anterior ankle resulting in increased joint space.

• Treatment: Rest and ankle brace for six weeks. NSAIDs for discomfort, and peroneal muscle strengthening exercises.
  

Anterior Tibial Spur

• Cause: Osteophyte growing inferiorly off anterior tibial lip. Often develops with repetitive high impact dorsiflexion motion.

• History: Patient reports pain with dorsiflexion when "pushing off'. No pain with weight bearing alone.

• Findings: Squatting, wall leans, or pushing off while walking reproduces the patient's symptoms of pain. No laxity of ankle joint. No pain with weight bearing.

• Test: Lateral X-ray view of ankle will reveal the anterior tibial osteophyte.

• Treatment: Limit activities that will exacerbate symptoms until surgical excision can be arranged
  .

• Cause: Loss of articular cartilage due to excessive wear and tear, an intra-articular fracture or malalignment of the ankle joint.

• History: Pain with weight bearing, barometric pain (weather)

• Findings: joint line swelling and tenderness, decreased range of motion. Three views (AP, lateral and mortise) of the ankle joint show joint narrowing, subchondral sclerosis and osteophytes.

• Treatment: Shock absorbing footwear, occasional use of casting and fracture boot for acute pain control. The patient should be referred to an orthopedist.

• Cause: Disregulation of the sympathetic sensory and motor enervation of a region of the body often due to trauma which may be trivial.

• History: Patient complains of diffuse, poorly localized pain, often out of proportion to the physical findings.

• Findings: Variable pattern of pain with weight bearing. Pallor, rubor, sweating, decreased skin temperature, edema, and atrophy with tight shiny skin.

• Tests: Diffuse uptake of the involved area on a bone scan. Temporary relief of pain and skin changes after a lumbar sympathetic block of the region. Many atypical variants are possible.

• Treatment: Intensive physical therapy, weight bearing, and pain abatement measures.

• Cause: Stretching of the superficial peroneal nerve when the foot is violently plantar flexed and inverted. Seen after ankle sprains.

• History: Paresthesia caused by the shoe rubbing on the superficial peroneal nerve.

• Findings: Tapping over the area of the superficial peroneal nerve will produce paresthesias over the dorsum of the foot (positive Tinel’s test).

• Tests: Blocking the nerve proximal to the stretched segment will temporarily eliminate the symptoms.

• Treatment: Insure footwear does not press on the nerve. Usually resolves over 3-6 months.

Antero-Medial/Medial Ankle Pain

• Cause: Loss of articular cartilage due to excessive wear, intra-articular fracture with joint incongruity, or malalignment of the ankle joint.

• History: Pain with weight bearing, barometric changes inducing pain (weather).

• Findings: Joint line swelling and tenderness. Decreased range of motion. Three views (AP, lateral, and mortise) will show joint narrowing, subchondral sclerosis, and osteophytes.

• Treatment: Shock-absorbing shoes, occasional use of fracture boot or cast for pain control. Persistent pain cases should be referred to orthopedics.

• Cause: May be due to direct trauma or a subtle stress fracture.

• History: Stress fractures begin as vague medial arch or dorsum of the foot pain that is aggravated by weight bearing.

• Findings: Painful to palpation over the navicular and with weight bearing. Occasional swelling and ecchymosis.

• Tests: AP Lateral and oblique of the foot. A CT is often needed to make the diagnosis.

• Treatment: For a complete fracture or non-union the patient will need an open reduction internal fixation (ORIF). An incomplete fracture should be treated in a non-weight bearing cast until healed. Patients can expect to return to full activity in 5-12 months.

• Cause: Fracture or fragmentation of a part of the talar dome associated with degeneration and detachment of the overlying cartilage-secondary to shear stress from the talus forcibly rotated within the mortise (severe ankle sprain). Also due to repetitive loading over time which is atraumatic but sufficient to cause the above described lesion. The exact mechanism is not understood.

• History: Vague ankle pain made worse by activity. Usually localized to the affected side. If the overlying cartilage is loose, a locking sensation may result.

• Findings: Point tenderness to pressure on the lesion, especially if the OCD is in the anterior talar dome where it can be palpated with the foot plantar flexed.

• Tests: Usually seen best on a mortise view of the ankle joint. A MRI will give the best assessment of cartilage involvement and extent of the lesion.

• Treatment: NSAIDs, activity modification to avoid high impact loading and a fracture boot. An orthopedist should be consulted, as the lesion may need to be debrided and drilled to avoid a protracted course.

Postero-Medial Ankle Pain

Posterior Tibial Tendon Insufficiency Syndrome

• Cause: Inflammation and degeneration of the tendon below the medial malleolus secondary to repeated stress from obesity, poor shoe support, tight heel cord, and a planovalgus foot type.

• History: Medial ankle pain of insidious onset aggravated by standing for long periods of time.

• Findings: Swelling and increased warmth along the course of the posterior tibial tendon. Point tenderness to palpation and contraction against resistance. The hindfoot does not invert on the single stance heel rise. The medial arch of the involved foot usually sags and is associated with forefoot abduction-all different than the contralateral side.

• Tests: Standing x-rays reveal a sag in the medial arch at the talonavicular or naviculocuneiform joints and forefoot abduction. A MRI will reveal intratendonous degeneration, but is often unnecessary as the diagnosis can be made clinically.

• Treatment: For severe pain and inability to walk a cast is the best initial treatment. Once the inflammation has subsided the patient can be managed with custom molded arch supports. An orthopedist should be consulted as the condition is usually progressive and may require early surgery to arrest the progression of the disease.

• Cause: Pressure or constriction of the posterior tibial nerve by ganglion cysts, venous varicosities, and the fascia of the abductor hallucis brevis produce a variety of sensory nerve symptoms. The symptoms may be aggravated by a pronated foot posture and activities, which violently pronate the foot.

• History: Patients present with complaints of paresthesias along the bottom of their foot.

• Findings: Positive Tinel’s test - tapping over the posterior tibial nerve behind the medial malleolus causes paresthesias along the plantar surface of the foot.

• Tests: Electromyelogram (EMG) and Nerve Conduction Velocity (NCV) studies show denervation and increased latencies across the tarsal tunnel.

• Treatment: Positive history, Tinel’s test, and EMG/NCV studies confirm the diagnosis in most cases. Footwear modifications that decrease pronation may help. Surgical release may be indicated so patients should be referred to an orthopedic surgeon.

• Cause: Fracture of the os trigonum or disruption of the synchondrosis between the talus and the os trigonum. The injury is caused by forcible plantar flexion of the foot while weight bearing. Symptoms occur when the foot is plantar flexed and the injured os trigonum is pushed upwards against the tibia.

• History: Vague posterior ankle pain usually on the medial side, aggravated by any plantar flexion maneuver.

• Findings: Positive posterior impingement test. The pain is reproduced when the foot is forcibly plantar flexed while the heel is pushed upwards.

• Tests: A lateral x-ray of the foot reveals the presence of an os trigonum. A transverse MRI through the talus at the level of the posterior talar process will show the size and medial-lateral orientation of the structure. One can inject lidocaine under floro through the back of the ankle to see if the pain is eliminated. However, the test may be positive for other conditions such as DJD, OCD. The diagnosis is a clinical one.

• Treatment: The os trigonum once injured rarely heals on it’s own due to the presence of synovial fluid. Excision of the os is usually necessary if it is still symptomatic after a 6-week trial of immobilization.

• Cause: Inversion injury leads to nonunion of avulsed fragment of bone from the distal fibula. Painful to pressure and any movements leading to traction on the fragment.

• History: Point specific pain at the tip of the fibula.

• Findings: Point tenderness to pressure at the distal tip of the fibula corresponding to the location of the avulsion fracture.

• Tests: Routine x-rays of the ankle reveal an ossicle at the tip of the fibula.

• Treatment: Once established the pain becomes consistent and predictable. Excision is the best treatment for eliminating the pain so the patient should be referred to an orthopedist.

• Cause: Degenerative tears due to excessive stress such as in the varus thrusting hindfoot. During an inversion injury, the peroneus longus pushes the peroneus brevis against the sharp lateral edge of the fibula and causes a traumatic longitudinal tear.

• History: multiple ankle sprains.

• Findings: Point tenderness associated with the tear is usually located between the lateral malleolus and the base of the fifth metatarsal. Eversion against resistance aggravates the pain.

• Tests: A MRI may show the tear but it is not 100 percent reliable. The diagnosis can usually be made clinically.

• Treatment: Symptomatic relief can be obtained by immobilization in a fracture boot. Persistent pain will require surgical debridement by an orthopedic surgeon.

• Cause: Failure of segmentation of the bones in the hind and mid tarsal joints. The result is a fibrous or osseous bridge across one or more of the tarsal joints that interfere with the normal motion of the joints. The most common coalition is the calcaneal navicular and followed by the talocalcaneal. The condition may be bilateral in up to 50 percent of patients.

• History: Sinus tarsi pain persisting after an ankle sprain or repetitive high impact loading from a demanding activity. The pain is persistent despite casting and other forms of immobilization and rest. The pain may be just in the sinus tarsi or in the inframalleolar region.

• Findings: Decreased subtalar motion is usually felt as a rubbery resistance when the subtalar joint is ranged.

• Tests: The oblique x-ray of the foot shows the calcaneal navicular coalition best. A lateral x-ray of the foot shows partial obliteration of the subtalar joint when a talocalcaneal coalition is present. The MRI coronal sections through the posterior talocalcaneal facet and sustentaculum tali will show the extent of the osseous bridge. An inflamed fibrous coalition may only show up on a bone scan.

• Treatment: Acute care involves the use of a cast or fracture boot to allow the inflammation at the coalition to subside. Once a coalition becomes symptomatic in military patients, it tends to persist. An orthopedic surgeon should be consulted early to avoid excessive delay in treatment decisions.

• Cause: Impingement of the os calcis against the fibula with excessive eversion caused by hyperpronation. The most common cause is the adult flatfoot secondary to posterior tibial tendon insufficiency.

• History: Pain in the sinus tarsi region.

• Findings: Increased hind foot valgus on the symptomatic side.

• Tests: X-rays show typical findings for flatfoot.

• Treatment: Please refer to the section on posterior tibial tendon insufficiency.

• Cause: Increased talar excursion in the mortise on uneven surfaces causes chronic irritation of the ankle joint

• History: Chronic pain in the sinus tarsi region with increased activity especially on sloping or uneven surfaces.

• Findings: Laxity to stress testing of the ankle in the AP and inversion directions reproduce the pain.

• Tests: Diagnosis is a clinical one.

• Treatment: An ankle corset will provide temporary relief but ligament reconstruction is the definitive solution.

Anterolateral Ankle Pain

• Cause: Failure of ankle ligaments to heal with normal tension after a sprain.

• History: trauma, or repeated sprains resulting in unsteadiness when standing on one foot or with excessive weight. "Roll out", or the ankle giving out when walking on uneven surfaces.

• Findings: Swelling, laxity with stress testing compared to other ankle joint (anterior drawer and inversion stress).

• Tests: AP lateral and mortise view x-rays of the ankle to rule out avulsion fracture of lateral malleolus.

• Treatment: Rest, ice, ankle corset for support, and crutches. After 2-3 weeks begin peroneal strengthening and balance board. The patient may need orthotic inserts, or lateral heel flare on the sole to resist foot inversion. If symptoms become chronic, refer for possible reconstruction of lateral ligaments.

Functional Instability

• Cause: Trauma, usually an inversion of the ankle with altered stretch receptors of ankle ligaments which cause a "late" response to ankle inversion.

• Findings: No laxity on stress testing of ligaments compared with other foot. When standing on one foot, the patient is unsteady compared to the other side. Obtain x-rays to rule out fractures of lateral malleolus and anterior process of calcaneous.

• Treatment: Rest, ice, ankle corset for support, and crutches. After 2-3 weeks, begin physical therapy including peroneal strengthening and balance board. May need orthotic-lateral heel flare for better stability. If symptoms become chronic, refer for possible reconstruction of lateral ligaments.

Lateral Foot and Midfoot Pain

Painful Os Peroneum Syndrome

• Cause: The os peroneum is an accessory or sesamoid bone with rounded borders encased within the tendon of the peroneus longus. Changes in the normal mechanics of foot, to include trauma, can cause pain in the region of the bone.

• Findings: Tenderness to palpation in the region of the lateral aspect of foot behind the fifth metatarsal. The bony mass is sometimes palpable.

• Tests: AP, lateral, and oblique x-rays of the foot which should show an accessory bone with rounded borders corresponding to the region of patients complaint (inferior / lateral to the cuboid bone).

• Treatment: Rest, ice, compression with an ace bandage, and elevation as possible for one month. If it continues to present a problem the patient should be referred to orthopedics for possible excision.

Jones's Fracture

• Cause: Basilar fifth metatarsal fracture at the junction of metaphysis and diaphysis. This region of bone has a poor blood supply, and has the potential for non-union. This injury often takes 2 -3 months to heal.

• Findings: Tenderness to palpation over the proximal fifth metatarsal.

• Tests: AP/ lateral and oblique x-rays of foot.

• Treatment: Non weight bearing cast for first 3 weeks then limited activity / fracture boot for 6 weeks.

Metaphyseal Fracture of 5th Metatarsal

• Cause: Inversion injury.

• Findings: Tenderness to palpation over 5th metatarsal, ecchymosis and edema.

• Tests: AP/ lateral / oblique x-rays of the foot.

• Treatment: Hard soled shoe and crutches for 4 weeks until patient can bear full weight.

• Cause: Inversion injury.

• Findings: Tenderness to palpation over the 5th metatarsal / cuboid joint, swelling, without gross deformity, and negative abduction stress test.

• Tests: AP lateral oblique x-rays of foot.

• Treatment: Weight bearing cast until asymptomatic (3 ~ weeks).

LisFranc (MUST Rule Out)

• Cause: Tarso-metatarsal joint fracture or dislocation seen with MVAs, falls, or from longitudinal force on a plantar flexed, inverted foot.

• Findings: Gross swelling on the dorsal surface of midfoot, and a positive abduction stress test resulting in an increase in joint space.

• Tests: AP, lateral and oblique x-rays are frequently normal due to the transitory dislocation, however a laterally dislocated second metatarsal is the most common finding. A fleck of bone can be seen between tarsal bones and widening of the 1^st and 2^nd metatarsal interspace.

• Treatment: Surgery as soon as possible. Must also be sure patient does not have a compartment syndrome of the foot.

Calcaneal-Cuboid Joint DJD

• Cause: Loss of articular cartilage due to wear and tear, or secondary to trauma.

• History: Pain over calcaneal cuboid surface with weight bearing, barometric pain.

• Findings: Calcaneal cuboid pain with forced inversion of foot.

• Tests: AP lateral and oblique x-ray of foot looking for joint narrowing and or subchondral sclerosis and cysts.

• Treatment: Medial arch inserts and footwear that cushions the heel. Occasionally casting or fracture boot for pain control. Refer persistent cases to orthopedics.

Stretched skin over fracture and dislocation deformities along with an increase in compartment pressures can lead to a tampanade of blood flow allowing for subsequent skin necrosis and sloughing. (i.e. subtalar dislocation)

The following list provides some examples of orthopedic emergencies:

• Impending penetration of bone spike through skin

• Vascular compromise

• Compartment syndrome

• Open fractures

• Open contaminated fractures

• Constrictive dressings and casts

Original submission by Ensign J. Groh MSIV and CAPT Frederick G. Lippert. Revised by CAPT Frederick G. Lippert, MC, USNR, Orthopedic Department, National Naval Medical Center, Bethesda, MD. (1999).