From the Clinic "Six months of heel pain… but it wasn't plantar fasciitis."

When runners develop heel pain, the diagnosis of plantar fasciitis is often made almost automatically.

In many cases, that's entirely appropriate.

But occasionally a patient arrives whose symptoms don't quite fit the usual pattern. Those are often the cases that remind me why making the correct diagnosis is far more important than rushing into treatment.

This patient was an experienced long-distance runner who had been unable to run for six months because of persistent pain affecting both heels.

Patient presentation

The patient attended my clinic with a six-month history of bilateral heel pain that had developed suddenly.

Prior to the onset of symptoms, they had been running approximately 30 miles each week and regularly completed marathon distances without difficulty. Since the pain began, they had been unable to return to running.

The symptoms were unusual.

Rather than describing the typical first-step pain associated with plantar fasciopathy, they reported sharp, stabbing pains during running together with tingling sensations, warmth within both feet and occasional weakness. Walking upstairs often produced shooting pain along the inside of the foot, while a dull ache remained even at rest.

Previous physiotherapy had focused on plantar fascia rehabilitation, but this had produced no meaningful improvement.

Assessment

Heel pain is one of the most common complaints I assess, but one of the most important lessons I've learnt over the years is that heel pain is not a diagnosis.

Clinical examination demonstrated a relatively high-arched foot posture and, importantly, a positive Tinel's test behind both ankles. Gentle percussion over the tibial nerve reproduced pins and needles radiating into the foot on both sides.

Diagnostic ultrasound was performed during the consultation.

The scan demonstrated only mild swelling of the tibialis posterior tendons bilaterally. Although this represented a minor abnormality, it was insufficient to explain the patient's neurological symptoms or the severity of their functional limitation.

There was no evidence of plantar fasciopathy, no significant tendon injury and no superficial varicosities or other obvious pathology.

At this point, the leading clinical diagnosis became tarsal tunnel syndrome.

However, one important feature continued to concern me.

The symptoms were affecting both feet almost identically.

Whilst bilateral tarsal tunnel syndrome certainly occurs, it is considerably less common than unilateral disease. That raised the possibility that another underlying cause remained undiscovered.

Rather than making assumptions, we agreed that further investigation was appropriate.

The diagnosis explained

Tarsal tunnel syndrome occurs when the tibial nerve becomes compressed as it passes through the narrow tunnel on the inside of the ankle.

Patients often describe burning pain, tingling, numbness or electric shock-like sensations radiating into the foot. Unlike plantar fasciopathy, symptoms frequently have a neurological quality and may not follow the typical pattern of morning pain.

Compression can occur for several reasons, including tendon pathology, inflammation, ganglion cysts, altered foot mechanics or, occasionally, no clearly identifiable cause.

Because the ultrasound had excluded the most common soft tissue causes of heel pain without fully explaining the patient's symptoms, MRI was arranged to investigate the deeper structures around the ankle.

MRI demonstrated small but almost identical ganglion cysts at the back of both ankles. These fluid-filled cysts were positioned in a location where they had the potential to contribute to irritation of the structures passing through the tarsal tunnel.

The findings were certainly interesting, but an important question remained.

Were these cysts actually responsible for the patient's pain, or were they simply incidental findings?

What we did

Rather than assuming the MRI findings explained everything, we decided to test the theory.

An ultrasound-guided injection of local anaesthetic and corticosteroid was performed into the posterior aspect of both ankles.

The purpose of the procedure was twofold.

Firstly, the corticosteroid offered the opportunity to reduce local inflammation and improve symptoms.

Secondly, and perhaps more importantly, the local anaesthetic acted as a diagnostic tool.

If temporarily numbing the tissues around the cysts relieved the patient's pain, it would strongly suggest that we had identified the correct source of the symptoms.

The patient was asked to keep a detailed pain diary over the following weeks so that we could accurately assess both the immediate and longer-term response.

The treatment plan

At review, the pain diary proved extremely valuable.

For the first three weeks following the injections, the patient reported being completely pain free.

The characteristic shooting pains had resolved and only a mild dull ache gradually returned during the fourth week.

Overall, symptoms had improved by approximately 20–30%.

Perhaps the most significant finding was the immediate response following the injections. The patient experienced numbness precisely within the treated area together with a marked reduction in their familiar pain.

This confirmed that the injected region was contributing to the symptoms and provided valuable diagnostic information beyond simply assessing whether the steroid had worked.

Given the positive diagnostic response, we discussed referral to a foot and ankle surgeon to consider further image-guided treatment. We also discussed the potential role of custom foot orthoses to reduce any ongoing mechanical contribution to the posterior ankle structures, together with physiotherapy once symptoms were better controlled.

Had the injections failed to produce any meaningful diagnostic response, further investigation of the lumbar spine and nerve conduction studies would have remained important considerations.

What can we learn from this?

One of the biggest lessons from this case is that not every investigation provides the final answer immediately.

The ultrasound ruled out several common causes of heel pain.

The MRI identified an abnormality that might explain the symptoms.

The diagnostic injection then helped determine whether that MRI finding was actually clinically relevant.

Each consultation answered one question and guided the next stage of investigation.

This structured approach reduces uncertainty and helps ensure that treatment is directed towards the true source of the patient's pain rather than simply the most obvious abnormality.

My specialist thoughts

Patients often think an injection is performed simply to reduce pain.

Sometimes that's true.

However, diagnostic injections can also provide some of the most valuable information in the entire assessment process.

The temporary effect of the local anaesthetic allows us to ask a very important question:

"Have we found the structure that's actually causing the symptoms?"

In this case, the answer appeared to be yes.

For me, that's one of the most rewarding aspects of specialist practice. It's rarely about making a diagnosis based on a single scan or a single test. It's about carefully gathering information, challenging assumptions and allowing each stage of the assessment to guide the next until we can build the clearest possible picture for the patient.

About the author

Mr Liam Stapleton MSc, PGCert, PGDip, FFPM RCPS(Glas), FRCPodM

Mr Liam Stapleton is a Consulting Podiatrist, Independent Prescriber and Specialist in Podiatric Sports Medicine. He has completed postgraduate qualifications in Independent Prescribing, Musculoskeletal Ultrasound, Advanced Clinical Practice, the Theory of Podiatric Surgery, and Podiatric Sports Medicine. His clinical practice focuses on the diagnosis and management of complex foot and ankle conditions, combining detailed clinical assessment with diagnostic ultrasound to provide accurate diagnosis and evidence-based treatment.

If you're struggling with persistent foot or ankle pain and would like a specialist assessment, including diagnostic ultrasound where appropriate, appointments can be booked with Kent Sports Podiatry at clinics across Kent.