Why is the underside (Plantar Fascia) of my foot painful?

The area is irritated and as a result the plantar fascia has become painful.  Previously Plantar Heel Pain (PHP) was considered an inflammatory condition however it is now accepted it is a degenerative condition. 

PHP is considered an overuse injury.  Overuse injuries occur because there is an imbalance between the load and capacity of the tissues. This may occur because of an increase in load or a reduction in the tissue capacity.

An increase in load such as starting a new job with increased time standing is often easier to identify than a reduction in capacity. Some people may report their load has not changed which may suggest there has been a reduction in tissue capacity. Tissue capacity can be influenced by psychological factors such as stress, increasing age, or changes in hormone levels.

Differential diagnosis (what else could it be?).

Differential diagnosis of pain in this region includes fat pad atrophy, neural entrapment or Calcaneal stress fracture.

People with Plantar Heel Pain (PHP) will report pain on the first steps in the morning or after prolonged periods of non-weight bearing. Pain will improve as they continue to walk, and they will often walk off the pain.

Patients with fat pad atrophy will report worsening pain as they continue to walk.  If you are an older person and female you are at increased risk of fat pad atrophy. A fat pad contusion may also be considered in younger people who report sudden onset heel pain after stepping down heavily. Fat pad involvement can be assessed through palpation (feeling the area by a trained Physiotherapist) and ultrasound to measure fat pad thickness.

Neuropathic (nerve) heel pain is uncommon. Neural entrapment should be suspected if you experience pain at rest or night pain, tingling or numbness in the foot.  You may also report more diffuse pain that travels proximally up the ankle. 

Consider a Calcaneal (Heel bone) stress fracture if you are a runner or are very active and you who present with heel pain.  Patients with a stress fracture will report rest pain, there may be swelling in the area and they will report pain on palpation of the calcaneus.

On examination.

Limited ankle range of movement has been reported as a risk factor in patients with PHP so if present it needs to be addressed as part of the treatment programme.  You are also likely to be very tender when the Plantar Fascia is palpated (felt) and if there is no pain throughout the Plantar Fascia then an alternative diagnosis should be considered.

Prognosis

The prognosis of PHP can vary significantly from weeks to months. There is a lack of good quality data on the timescale for improvement in PHP as studies usually only include patients who have had symptoms for more than 3 months.  PF is usually a self-limiting condition, with more than 90% of patients achieving symptomatic relief with 3-6 months of conservative treatment. You should be very aware that your symptoms will not resolve overnight.

Treatment

The management of PHP will depend on the presentation of the patient.  The management of a runner will be different from a person with a sedentary job who is overweight. Tailoring the treatment programme to you specifically is really important, as there are lots of different treatments, which have been found to be equally effective as each other.

Active person.

For people who are active load management is key. This might include having discussions with your work to facilitate a reduction in time spent standing or reducing your current exercise levels. With regards to load management your Physio will give you clear guidance for how to progress.  A runner should keep running as long as it does not aggravate your pain more than 2/10 and your pain returns to your normal level by the next day.  If you are unable to tolerate running, start with walking and progress to jogging.  You could try to run on a flat soft surface such as sand or woodland.

Sedentary person.

Try to use active approaches to increase your capacity and load management.  If you are struggling to exercise/are not interested in the loading programme, then the stretching programme is an alternative. The type of exercise prescribed will depend on the person and the guidance and knowledge of the clinician.  If you are overweight, your Physio should work with you to address this. Weight loss is difficult as it does not happen quickly, but it can help reduce the load placed on the plantar fascia.

Plantar Fascia Stretching

To perform plantar fascia stretching, place the foot on the opposite knee and extend the toes and ankle joint as much as possible. This should be maintained for 10 reps of 10 seconds and repeated 3 times per day (DiGiovanni et al., 2006). Plantar fascia stretching combined with calf stretching has been shown to be superior to isolated plantar fascia stretching.

Strengthening

Heavy slow resistance training can be performed by placing a rolled-up towel under the toes to maximally extend them and increase the tensile load across the plantar fascia. Your Physiotherapist will prescribe calf/ankle strength training in this position for you, ensuring you are comfortable with no flare up of pain.

Orthotics

Orthotics are commonly used for the management of PHP. The type of orthotics used should depend on the patient.  Some people prefer a soft silicone insole whilst others prefer firmer supportive insoles. It is not important to be prescribed customised insoles over off the shelf orthotics.  Both have been shown to be better than placebo. In patellofemoral pain syndrome the best indicator that an orthotic will work is if you felt it was comfortable when it was put it into your shoe.  There is no evidence to suggest a specific type of insole is better in PHP so use what feels most comfortable.

Corticosteroid Injection

There is debate around the role of corticosteroid injections in the management of PHP. Clinicians are often worried about the risk of plantar fascia rupture. A Cochrane review published in 2017 looked at the effect of steroid injections PHP. The review concluded that there is low quality evidence that local steroid injections compared with placebo or no treatment may slightly reduce heel pain up to 1 month. They also reported that although rare, serious adverse events were under-reported, and a higher risk cannot be ruled out.  Corticosteroid provides a short-term pain reduction of 4-8 weeks. This may provide a window of opportunity following an injection to perform heavy slow resistance training to prolong the effect. However, given that PHP is not strongly linked to inflammation, the usefulness of steroid injection, which is a strong anti-inflammatory, does not necessarily seem helpful.

Conclusion

Speak to your Physiotherapist to get a diagnosis and treatment plan under way. You don’t need to suffer with PHP but understand that it can be a stubborn issue!

Thanks for reading!