Diagnosing calcaneal bone marrow oedema requires more than simply identifying pain beneath the heel. Because its symptoms overlap considerably with plantar fasciosis, Baxter's nerve entrapment and stress fractures, the diagnosis depends on combining a detailed clinical assessment with appropriate imaging. The goal is not only to identify bone marrow oedema but also to determine whether it is the primary cause of the patient's symptoms or one component of a more complex presentation.
The assessment begins with a thorough history. Understanding when the pain developed, how it behaves throughout the day, what activities aggravate it and which treatments have already been attempted provides valuable information. Patients often describe heel pain that has gradually worsened with activity and failed to improve despite appropriate treatment for plantar fasciosis. A recent increase in walking, running or sporting activity may suggest a bone stress reaction rather than isolated plantar fascia degeneration.
Clinical examination then helps narrow the diagnosis. The location of tenderness, the response to loading, gait assessment and examination of foot biomechanics all contribute to understanding the likely source of pain. Patients with calcaneal bone marrow oedema often demonstrate tenderness over a broader area of the heel than those with isolated plantar fasciosis. Compression of the calcaneus from the sides or direct pressure into the heel may reproduce symptoms, although these findings are not specific and should always be interpreted in the context of the overall examination.
Diagnostic ultrasound is usually my first imaging investigation for chronic heel pain because it provides excellent assessment of the plantar fascia, tendons, bursae and surrounding soft tissues. Ultrasound can identify plantar fascia thickening, degeneration, partial tears and associated pathology while also assessing for Baxter's nerve irritation or heel fat-pad abnormalities. However, ultrasound cannot visualise changes occurring within the bone marrow itself. A normal ultrasound therefore does not exclude calcaneal bone marrow oedema.
When clinical suspicion remains high, MRI is the investigation of choice. MRI is considered the gold standard because it can detect increased fluid within the cancellous bone long before changes become visible on plain X-rays or CT scans. On MRI, bone marrow oedema typically appears as an area of increased signal intensity on fluid-sensitive sequences such as T2-weighted or STIR images and reduced signal intensity on T1-weighted images. These findings indicate a bone stress reaction rather than simply degenerative soft tissue disease.
MRI also provides an important advantage by identifying other conditions that commonly coexist with or mimic bone marrow oedema. It can demonstrate plantar fasciosis, partial plantar fascia tears, stress fractures, inflammatory arthropathies, heel fat-pad pathology, tendon disorders and, in rare cases, infection or bone tumours. This comprehensive assessment helps ensure that treatment is directed towards the true source of the patient's symptoms rather than relying on assumptions.
One important point is that MRI findings must always be interpreted alongside the clinical presentation. Bone marrow oedema can occasionally be identified in patients with relatively minor symptoms, particularly athletes following periods of intense training. Conversely, patients with significant heel pain may demonstrate only modest imaging changes. Imaging should therefore support the diagnosis rather than replace careful clinical reasoning.
The diagnosis becomes particularly important because treatment differs significantly from that of plantar fasciosis. If bone marrow oedema is mistaken for plantar fascia degeneration, patients may continue receiving treatments directed at the fascia while the underlying bone stress injury persists. Recognising the condition early allows the clinician to reduce mechanical loading through the calcaneus and prevent progression to a more significant stress injury.
Ultimately, diagnosing calcaneal bone marrow oedema requires looking beyond the most common diagnosis. Combining a detailed history, careful examination, diagnostic ultrasound and MRI where indicated provides the most reliable pathway towards identifying this frequently overlooked cause of chronic heel pain.