A 57-year-old African-American woman presents to the Physical Medicine and Rehabilitation (PM&R) clinic complaining of right-sided foot and ankle pain with no preceding injury or trauma. The pain has been present for about 9 months and is gradually worsening. She reports that her pain is constant, aggravated by prolonged standing and walking. She takes occasional naproxen which seems to help temporarily. There is mild swelling in the right ankle. She denies any pins/needles sensation or numbness. Her daily activities, including walking and her job duties, are interrupted because of the pain. She denies any focal weakness in the lower extremities. Her review of systems is significant for intermittent low back pain, otherwise negative. She was seen by her primary care doctor and had x-ray imaging of the foot and ankle.
Past medical history: She has a history of hypertension (HTN) for which she is on hydrochlorothiazide, 25 mg O.D. for the past 10 years. She is postmenopausal.
Past surgical history: Lumbar spine surgery (decompression and fusion) 4 years ago.
Social history: She works as a sales manager, lives with her family (husband and one daughter) in an elevator accessible apartment on the fourth floor.
Allergies: No known drug allergy.
Medications: Hydrochlorothiazide, 25 mg O.D., occasional Naproxen.
BP: 130/72 mmHg, RR: 18/min, PR: 72 per min, Temp: 97.4° F, Ht: 5’6”, Wt: 180 lbs, BMI 29 kg/m 2
Physical Examination
General: She is alert and oriented to person, place, and time. A well-developed, obese lady without significant distress.
Extremities: No skin rashes, surgical scars, or open wounds. Bilateral genu valgum. Bilateral pes planus.
Musculoskeletal examination
Range of motion (ROM) of the lumbar spine: Within functional limits, however, mild pain is reported in the midline of the lower lumbar spine with extension.
Motor exam: 5/5 and symmetric in all muscles groups of bilateral upper and lower extremities.
Deep tendon reflexes (DTR) exam: 2+ in both upper and lower extremities.
Sensory exam: Intact to light touch and pinprick in all dermatomes in both lower extremities.
Gait: No gross foot-dragging or slapping.
Straight leg raise test: Negative.
Patrick (flexion, abduction, and external rotation) test: Negative.
Ely test: Tight rectus femoris on the right side.
No tenderness at the greater trochanters bilaterally
ROM of the knee: Within functional limits.
ROM of the ankle with subtalar neutral: Within functional limits except for heel cord tightness on ankle dorsiflexion.
Foot and ankle palpation: tenderness at the medial hindfoot between the medial malleolus and navicular tuberosity
Silfverskiold test: Positive (more than 10-degree change of ankle dorsiflexion on knee flexion from knee extension [with limited ankle dorsiflexion <5 degrees]) on both sides.
Double heel-rise test: Intact.
Single heel-rise test: Impaired hindfoot (heel) inversion on the right side and intact on the left side.
Labs: White blood cell (WBC): 6000 cell/mL; hemoglobin (Hg): 12.6 g/dL
The General Approach to Foot and Ankle Pain
During the approach to a patient with gradual onset of foot and ankle pain, the initial focus should be to differentiate local pathologies from pain referred from proximal pain generators, such as lumbar, hip, or knee pathologies. It is also important to differentiate between musculoskeletal and neuropathic pain generators.
If proximal pain generators, such as the spine, hip, and knee pathologies are ruled out, then local foot and ankle pathologies can be further classified based on the location of maximal pain and tenderness.
Frequently, patients can present with multiple independent pathologies in different parts of the lower extremities that can be caused by similar faulty biomechanics. Taking into consideration the closed kinetic chain during functional activities (such as standing and walking), recognizing faulty biomechanics is important for diagnosis, understanding underlying etiologies, and planning the treatment.
It is also important to recognize if there are any red flags that would prompt urgent imaging and further investigation.
The physical examination can follow the aforementioned sequences by localizing the pain generators in the foot and ankle region. Tenderness can be a compass to the local pain generator, especially if the examiner has sound knowledge of the foot and ankle surface anatomy ( Table 8.1 ).
| Region | Pathologies and Notes |
|---|---|
| Plantar heel | Plantar fasciitis: pain on the medial calcaneal tuberosity. Most common cause of plantar heel pain Plantar fibromatosis: palpable nodule often with tenderness, distal to the insertion of the plantar fascia |
| Fat pad atrophy: pain after walking, frequently with a history of steroid injection to the plantar fascia | |
| Stress fracture: vague deep pain, associated with risk factors, such as osteoporosis, diabetes mellitus, longstanding steroid use, calcaneovarus, or history of a recent change inactivity Bony tumor (e.g., interosseous lipoma) | |
| Peroneus longus and brevis tendinopathy/tenosynovitis/tear | |
| Posterior heel/ankle | Noninsertional Achilles tendinopathy/tear: Most common cause of posterior heel pain, 2–3 inches proximal to the insertion to posterior calcaneal tuberosity Insertional Achilles tendinopathy: pain at the insertion of the tendon |
| Os trigonum syndrome: deep posterolateral pain ± h/o minor ankle injury | |
| Flexor hallucis longus tendinopathy/tenosynovitis: posterior medial hindfoot/ankle pain ± h/o ankle sprain or overuse | |
| Retrocalcaneal/superficial calcaneal bursitis: worse wearing tight shoes | |
| Dorsal ankle | High ankle sprain (syndesmosis): persistent pain after eversion ankle sprain ± instability |
| Anterolateral impingement syndrome: gradual onset of pain after injury, pain during the terminal stance phase of gait | |
| Osteochondritis dissecans: chronic pain after an ankle sprain. Often poorly localized | |
| Talonavicular and calcaneocuboid joint/ligament sprain or arthritis | |
| Medial ankle/hindfoot | Posterior tibialis tendinopathy, tear, and tenosynovitis: Most common cause of acquired flat foot, pain between the medial malleolus and navicular tuberosity. Less commonly, flexor digitorum longus tendinopathy |
| Deltoid ligament sprain: h/o eversion injury | |
| Arthritis: local pain h/o tarsal coalition or abnormal foot alignment (pes planus, cavus) | |
| Lateral ankle/hindfoot | Lateral ankle ligament sprain: Most common cause of lateral ankle pain, h/o inversion injury |
| Peroneal tendinopathy, tear, tenosynovitis, and subluxation | |
| Sinus tarsi syndrome: persistent local pain (at sinus tarsi) after ankle sprain | |
| Calcaneocuboid joint arthritis | |
| Lateral midfoot | Cuboid-fourth metatarsal arthritis, a subluxation (cuboid subluxation ± minor trauma/sprain), and sprain |
| Painful os peroneal syndrome | |
| Medial midfoot | Kohler disease (navicular osteochondrosis), Mueller Weiss syndrome (navicular osteonecrosis) Painful accessory navicular syndrome Naviculocuneiform arthritis: often associated with hypermobile cuneiform-first metatarsal joint |
| Lisfranc injury | |
| Flexor hallucis longus or flexor digitorum longus tendinopathy or tethering of tendons | |
| Medial forefoot | Gout: MC cause of acute nontraumatic disabling foot pain. First metatarsophalangeal (MTP) joint; MC location Hallux rigidus/limitus: pain on the dorsum of first MTP joint initially Hallux valgus with bursitis: pain on the medial side of first MTP, irritated by tight shoes |
| Sesamoiditis, sesamoid fracture/necrosis: pain on the plantar aspect of the first MTP joint | |
| Subluxation or dislocation of second metatarsophalangeal joint | |
| Stress fracture of second metatarsal bone; often with preceding activity change Freiberg disease (osteonecrosis of second metatarsal head): more common in adolescent female | |
| Lesser toes | Intermetatarsal bursitis ± irritation of an interdigital nerve Taylor’s bunion (Bunoinette deformity) on the lateral side of fifth metatarsal head |
| MTP joint arthritis/synovitis (highly involved in inflammatory arthropathy; underrecognized) Lateral overloading syndrome: often h/o medial arch support use |
Common Differential Diagnoses for Foot and Ankle Pain
- 1.
Tendon disorders (tendinopathy, tenosynovitis, tear) —during the initial phase, pain from tendinopathy is usually mild in intensity, localized, intermittent and occurs with activities that require contraction of the tendon/muscle. The pain then gradually becomes constant as the condition progresses. Acute injuries from trauma or chronic overuse injuries with or without faulty biomechanics are common causes of tendon dysfunction. Patients can easily recognize the inciting event in the case of trauma; however, they may have difficulty associating subtle faulty biomechanics or overuse injuries with the underlying etiology of tendon dysfunction. Common tendon disorders in the foot and ankle include Achilles tendon on the posterior heel, posterior tibialis tendon (PTT) on the medial aspect of the hindfoot and ankle, flexor hallucis longus tendon on the posteromedial aspect, and peroneus tendon on the lateral aspect.
- I.
Achilles tendinopathy: The patient typically presents with gradual onset of pain and tenderness 1 to 2 inches proximal to the insertion of the tendon. Symptoms are often aggravated by activities, such as walking and running, which require repetitive soleus muscle contraction. If the pain is located at the insertion site (posterior calcaneal tuberosity), insertional Achilles tendinopathy should be suspected.
- II.
PTT dysfunction: The patient typically presents with pain and swelling on the medial hindfoot (between the medial malleolus and navicular tuberosity). Symptoms get worse with prolonged standing and walking. Insufficient posterior tibialis muscle/tendon is the most common reason for acquired flat foot (pes planus) deformity. PTT is at a mechanical disadvantage in pes planus. With the progression of the PTT dysfunction and pes planovalgus deformity, the patient may then complain of pain in the lateral hind and midfoot
- I.
- 2.
Bursitis —retrocalcaneal bursa, located between the posterior calcaneal tuberosity and Achilles tendon, can cause pain that is similar to insertional Achilles tendinopathy. Bursitis pain is usually constant and worsens with external compression (often caused by tight shoes). With significant effusion, there is a loss of contour of the Achilles tendon. It is often difficult to differentiate precalcaneal bursitis (adventitial bursitis superficial to the Achilles tendon) from retrocalcaneal bursitis. Precalcaneal bursitis can coexist with retrocalcaneal bursitis, and both usually are aggravated by external compression. The patient usually reports relief of pain when walking barefoot or with slippers and shoes without heel countertop.
In the lateral forefoot region, the intermetatarsal bursa can be inflamed, causing metatarsalgia. Wearing tight shoes squeezing the forefoot can aggravate the pain. Similar to the retrocalcaneal and precalcaneal bursitis, patients prefer to walk barefoot or to use slippers. The patient may also complain of sensory symptoms, such as tingling and pins/needle sensation because of the proximity of the bursa to the intermetatarsal nerve.
- 3.
Ligament injury (sprain) —ankle sprain is one of the most common sports injuries and is the most common cause of ligamentous injury. It is particularly common in sports or activities that require cutting, changing direction, jumping, or tackles. The anterior talofibular ligament is the most commonly injured ligament, typically from inversion and the ankle plantarflexion mechanism. A medial ankle sprain is less common and usually requires significant trauma to occur. Occasionally, there could be bony injury involvement of the proximal fibula (Maisonneuve fracture). A high ankle sprain involves ankle syndesmosis injury, affects ankle mortise stability, and can be a source of chronic ankle pain with instability. Other ligament sprain injuries include the bifurcate ligament on the lateral midfoot and Lisfranc ligament on the medial forefoot.
- 4.
Stress fracture —metatarsal bone is the most common site followed by the calcaneus. History of trauma or change of activities may be missing or underrecognized by the patient and clinician. Risk factors include diabetes, longstanding steroid use, osteoporosis, mineral bone disease, and abnormal biomechanics (including calcaneovarus). The patient often complains of deep and vague pain. Pain often worsens with heel walking in cases of calcaneal stress fracture (but is able to stand and bear weight differentiating it from a displaced fracture). The clinician has to be aware of the initial lagging of plain x-rays in revealing pathologic findings.
- 5.
Plantar fasciitis— heel pain from plantar fasciitis is the most common cause of foot pain. Typically located on the plantar aspect of the heel, worse with the first few steps in the morning then gradually improves. Also it may get worse with prolonged standing and walking, especially with low heeled shoes. Tenderness is usually located at the medial tuberosity of the calcaneus or along the proximal plantar fascia.
- 6.
Osteoarthritis (OA)— primary OA is relatively rare in the ankle (tibiotalar) joint. Arthropathy of the ankle joint usually involves a prior history of trauma. The most common joint involved in primary OA in the foot and ankle region is the first metatarsophalangeal joint in the forefoot accompanied by pain with standing and walking (late stance phase initially) and stiffness. It is not uncommon in the talonavicular joint at the medial hindfoot, which usually manifests as pain that is worse in the initial loading phase of stance. The pain is usually insidious in onset. Identification of different phases of gait can be useful to further localize the pathology.
- 7.
Fat pad atrophy— pain and discomfort from fat pad atrophy is an underrecognized entity that mimics pain from plantar fasciitis. It can be insidious and typically occurs after repeated steroid injections (or penetrating trauma to fat pad). The patient presents with difficulty walking with the hard-soled shoes or barefoot.
- 8.
Rheumatoid arthritis (RA) —frequently involves the metatarsophalangeal joint presenting initially with metatarsalgia. Later in the course, RA involves joints and tenosynovium in the hindfoot and midfoot with subsequent pain and swelling in these locations. With advanced RA disease, joint destruction and tendon rupture can occur causing foot and ankle deformity and diffuse pain. RA can be accompanied by morning stiffness with frequent involvement of other joints and systemic manifestations.
- 9.
Malignancy —foot and ankle is not a common site for bony tumor or metastasis, and most tumors are usually asymptomatic or have a nonspecific presentation. Most palpable masses in the foot and ankle are not cancerous. Therefore diagnosing tumors in the foot and ankle region may be challenging. Symptomatic patients may present with pain which can be worse during rest (supine position or at night), and systemic manifestations, such as weight loss.
- 10.
Osteomyelitis —if a patient with underlying risk factors, such as diabetes mellitus, vascular disease, immunocompromise, presents with a chronic nonhealing ulcer, then the suspicion for osteomyelitis should be high. It usually presents with constant pain, often no fever. WBC count is often normal but C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) are frequently elevated.
- 11.
Lumbosacral radiculopathy— most commonly occurs at the L5 followed by the S1 level. It presents with low back or buttock pain radiating down to the foot (medial and dorsal in L5 and lateral aspect in S1 radiculopathy). Motor and/or sensory deficits in the distribution of the involved root can be a significant finding that supports the diagnosis. Diagnosis can be challenging in patients who only present with pain because there are a few musculoskeletal mimickers for radiculopathy. Coexisting low back pain and foot pain can be misinterpreted as lumbosacral radiculopathy because of the fact that low back pain is very common in the general population.
- 12.
Peripheral polyneuropathy —sensory symptoms (pain, numbness, tingling, or pins/needles sensation) can be present along with the distribution of peripheral nerves (often distal and symmetric in peripheral polyneuropathy). Peripheral neuropathy related to diabetes can present with symptoms that start distally from the toes and gradually move proximally known as “dying-back phenomenon.”
- 13.
Local entrapment neuropathy —should be differentiated from lumbosacral radiculopathy and peripheral polyneuropathy. It is typically limited to the distribution of a single peripheral nerve, usually from stretching or compression of the nerve. Common entrapment neuropathies in the foot and ankle include tarsal tunnel syndrome, distal tarsal tunnel syndrome involving inferior calcaneal nerve (Baxter nerve), medial plantar neuropathy (jogger’s foot), and anterior tarsal tunnel syndrome ( Fig. 8.1 ). Baxter nerve entrapment syndrome requires particular attention because it does not have cutaneous sensory innervation; thus there are typically no cutaneous sensory symptoms such as numbness, tingling, or pins/needle sensation. It manifests with deep aching pain in the plantar aspect of the heel similar to plantar fasciitis. In recalcitrant heel pain, Baxter entrapment neuropathy should be included in the differential diagnosis ( Table 8.2 ).
