Plantar Fasciitis is the most common cause of heel pain presenting in the clinic with millions suffering from this condition each year.
studies suggested that 10% of the population will suffer from heel pain at some point and 15% of all athletic and non-athletic adult population will report heel pain.
But does all heel pain caused by plantar fascia?
If the patient's pain is not localized to the attachment of the plantar fascia or if it does not resolve with conservative treatment. this should lead the practitioner to consider other possible causes of the patient's pain.
It is critical for practitioner to consider the wide range of possible differential diagnoses before coming to a conclusion on the aetiology of the pain.
there are around 40 conditions that could cause heel pain, check this list of these alternative aetiologies;
Plantar Heel Pain Differential Diagnosis
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let us take a closer look at these potential aetiologies and review different clinical exam and diagnostic findings that are common with each. there are also certain clues within the patient history that can lead you to an accurate diagnosis.
Tarsal tunnel syndrome
Is a rare entrapment neuropathy that involves compression of the posterior tibial nerve or one of its distal branches as it courses beneath the flexor retinaculum (laciniate ligament) along the medial heel.
Pain, burning, numbness and tingling in the heel that may radiate to the plantar aspect of the foot and into the toes may be present in patients with tarsal tunnel syndrome. However, this condition is often underdiagnosed, especially in patients with diabetes who may already have symptoms of peripheral neuropathy or lumbar radiculopathy.
It is important to consider conditions that may compress or irritate the tibial nerve at the tarsal tunnel.
Potential causes may include previous trauma to the area; pes planus that may stretch the contents of the tarsal tunnel; morbid obesity; space-occupying lesions (ganglion cysts, varicose veins, tumors, etc.); tendonitis in an active person from repetitive stress after running or walking; or increased oedema after excessive standing.
In a patient with chronic tarsal tunnel syndrome, there may be weakness of the intrinsic flexors and toe abductors of the foot.
In the more advanced cases, one may note muscle atrophy.
A comprehensive clinical examination is key to differentiating tarsal tunnel syndrome from other soft tissue causes of heel pain.
Symptoms will generally be unilateral. Besides palpating for a space-occupying lesion and percussing the nerve and its branches around the tarsal tunnel in search of a positive Tinel’s sign, the practitioner should also dorsiflex and evert the foot for five to 10 seconds, hoping to be able to reproduce the paresthesia the patient may be experiencing.
Be sure to have the patient stand and ambulate during the encounter to observe for any excessive pronation, supination or hindfoot malalignment that may give you clues as to the root of the cause.
MRI is an adjunctive imaging modality that can inspect for any soft tissue abnormality in or around the tarsal tunnel. However, to confirm a tibial nerve lesion, make sure to refer the patient to a neurologist for sensitive sensory and motor nerve conduction velocities (NCVs) as well as electromyography if initial conservative treatment fails.
The practitioner would look for increased distal latency in the nerve conduction velocity as well as fibrillation potentials that indicate axonal injury to the muscles innervated by the tibial nerve distal to the tarsal tunnel.
Initial treatment for the patient may involve the use of oral non-steroidal anti-inflammatory drugs (NSAIDS) for initial reduction of inflammation along with several weeks of rest, ice and elevation of the involved foot.
The practitioner could attempt to address the mechanism of injury by utilizing custom orthotics to correct foot posture and provide better support of the foot with ambulation. If the patient wears boots to ambulate or while he or she is at work, padding of the area could prove beneficial to reduce pressure and irritation to the nerve. If the patient does not improve with this measure, the next step would be to immobilize the foot for four to six weeks with the use of a CAM boot or splint along with corticosteroid injections and possible referral to physical therapy.
Depending on the success of the conservative treatment and the severity of the results from the diagnostic studies, the practitioner should consider a local nerve block before considering surgical treatment. If the pain ameliorates or completely subsides with the injection, then one might find success with subsequent decompression of the tibial nerve at the tarsal tunnel and its branches. Finally, if there is a space-occupying lesion present within the tarsal tunnel or adjacent area, it would be prudent to remove the lesion to reduce the pressure around the nerve.
Baxter’s nerve entrapment
Is a condition that typically consider after the patient has not benefitted much from aggressive conservative treatment. It involves compression or entrapment of the first branch of the lateral plantar nerve. This condition tends to be underdiagnosed and is often mistaken for plantar fasciitis due to the patient typically presenting with pain on the plantar medial aspect of the heel. On the contrary, Baxter’s nerve travels between the abductor hallucis muscle and the medial calcaneal tuberosity, running medial to lateral on the heel to finally innervate the abductor digiti minimi muscle. Some predisposing factors include obesity, overpronation, hypertrophy of the abductor hallucis muscle at its origin or increased inflammation secondary to chronic plantar fasciitis.
Both tarsal tunnel syndrome and Baxter’s neuritis share many symptoms I previously mentioned such as a deep ache and paresthesia, but without the sensory deficits. Accordingly, it is important to rule out plantar fasciitis, tarsal tunnel entrapment and other calcaneal pathology.
One should palpate the proximal and distal plantar fascia, and the origin of the abductor hallucis muscle where the nerve travels beneath it. Palpate and percuss the tibial and medial calcaneal nerves, and perform the side to side heel squeeze test to see if this elicits symptoms. During manual muscle testing, include the abductor digiti minimi in your assessment and look for the patient’s ability to abduct the fifth digit. If you note weakness or inability to perform this movement, then consider referring the patient for medical imaging and further testing.
Radiographs for this condition will not help much in the diagnosis. But MRI is the most accurate confirmatory imaging study. During mild stages of Baxter’s neuritis, look for inflammation around the proximal aspect of the plantar fascia that may be causing pain from compression of the nerve. In advanced cases in which there is moderate to severe motor weakness of the abductor digiti minimi muscle, be on the lookout on MRI for decreased signal intensity on T1-weighted images and increased signal intensity on T2-weighted images with fatty infiltration of the abductor digiti minimi, indicating decreased muscle volume and atrophy.
In most cases, conservative care is the mainstay treatment for Baxter’s neuritis. The approach is similar to what one may attempt for treating plantar fasciitis. The initial goals are to decrease the pain with analgesic medication, reduce the inflammation around the area with oral NSAIDs or a corticosteroid injection, emphasize equinus stretching via bracing and remove any aggravating factor that may be causing nerve irritation with padding or foot orthotics. If conservative treatment fails and one notices atrophy of the abductor digiti minimi muscle, then complete surgical neurolysis of Baxter’s nerve is indicated.
Fat pad atrophy
This type of heel pain is more common in the obese or elderly patients above 60 years of age. These patients will present with deterioration or reduction of the integrity of the adipose tissue, which provides cushioning and shock absorption to the heel. When describing the pain, patients relate a deep ache and tenderness at the centre of the plantar heel that is more often bilateral. The pain tends to be more diffuse along the plantar heel in comparison to plantar fasciitis or nerve entrapments where the location of the pain can be more precise. These patients will complain of worsening symptoms after prolonged periods of standing and walking, and will relate having night pain with rest.
During the comprehensive clinical examination, identify if there is thinning of the fat pad not only of the heel but also at the forefoot underneath the metatarsals, where one can easily palpate bony prominences. Also, work your way around the heel, avoiding the point of maximum tenderness to try and rule out other possible soft tissue causes of heel pain like plantar fasciitis or nerve entrapment. Then try to reproduce the symptoms with direct palpation to the central aspect of the heel.
Fat pad atrophy treatment is straightforward than others. Initially ask the patient about the possibility of modifying daily activity to decrease periods of standing or ambulating. Also emphasize proper shoe gear with the possible use of accommodative orthotics with plenty of shock-absorbing material in order to decrease pressure to the affected area. Another alternative to supportive orthotics is the use of heel cups if there is no other underlying biomechanical factor such as a cavus foot.
Finally
It is important to realize there are several different causes to heel pain, do not jump to the most common diagnosis of Plantar Fasciitis. most importantly, taking a detailed patient medical/ sport history can lead you down the proper route toward an accurate conclusion.
References:
Crawford F, Atkins D, Edwards J. Interventions for treating plantar heel pain. 2003
Rome K. Extrinsic risk factors and aetiological factors in plantar heel pain: A review of the literature. Lower Extremity 1998.
Rome K. Extrinsic risk factors and aetiological factors in plantar heel pain: A review of the literature. Lower Extremity 1998.
Tisdel CL, Donley BG, Sferra JJ. Diagnosing and treating plantar fasciitis: conservative approach to plantar heel pain. Cleveland Clinic Journal of Medicine 1999.
Monenza J. A guide to conservative treatment for heel pain. Podiatry Today 2003.
Relationship between intrinsic foot muscle weakness and pain: a systematic review. Penelope J Latey, Joshua Burns, Claire Hiller, Elizabeth J Nightingale 2014.
Obesity and pronated foot type may increase the risk of chronic plantar heel pain: a matched case-control study. Irving DB, Cook JL, Young MA, Menz HB.2007