Retrocalcaneal bursitis

Retrocalcaneal bursitis is a painful inflammation of the bursa located between the anterior surface of the Achilles tendon and the posterosuperior part of the calcaneus. The normal role of this small bursa is to help the Achilles tendon glide over the bone during ankle movements. In runners, it can become painful when it is subjected to repeated compression, shear and mechanical overload.

The term simply describes its location: retro (behind) + calcaneal (at the calcaneus) + bursitis (inflammation of a bursa). It lies deep to the Achilles tendon, which distinguishes it from superficial retro-Achilles bursitis, located between the tendon and the skin and much more directly influenced by friction or pressure from the shoe.

Retrocalcaneal bursitis is frequently associated with insertional Achilles tendinopathy, a posterosuperior prominence of the calcaneus (Haglund’s deformity), calcifications at the Achilles insertion, a sudden increase in running volume or intensity, or shoes that put significant pressure on the rearfoot. It is therefore important not to regard all pain at the Achilles tendon insertion as simple “tendinopathy”: the condition may mainly involve the bursa, the tendon, the bone, or several of these structures at the same time.

The back of the heel contains several closely interlinked structures: the Achilles tendon, the calcaneus, the retrocalcaneal bursa, the subcutaneous retro-Achilles bursa, the soleus muscle, the gastrocnemius, Kager’s fat pad, as well as the subtalar joint and surrounding structures.

The retrocalcaneal bursa lies between the anterior part of the Achilles tendon in front and the posterosuperior part of the calcaneus behind: it forms a true gliding interface between the tendon and the bone.

🔍 Click on the image to enlarge it

Role of the bursa and the vicious circle

The bursa normally allows the Achilles tendon to move over the calcaneus with minimal friction. When the ankle goes into dorsiflexion, particularly when the knee moves forward over the foot, the anterior part of the Achilles tendon and its bursa can be compressed more against the calcaneus. In an athlete with irritation in this area, this compression can become painful and sustain a vicious circle: compression → irritation → swelling of the bursa → less available space → further compression.

Biomechanics in runners

Running places considerable stress on the ankle-foot complex. With each stride, the foot makes contact with the ground, the ankle absorbs part of the load, the triceps surae gradually comes under tension, the Achilles tendon stores energy, and this energy is then released during propulsion. The tendon can withstand high loads; the problem arises when the tissues’ capacity to adapt is exceeded. Bursitis, however, is particularly influenced by local compression, and not only by the amount of force generated by the tendon.

Role of dorsiflexion

Dorsiflexion brings the Achilles tendon closer to the posterosuperior part of the calcaneus: marked dorsiflexion can therefore increase compression of the insertional region. This explains why some patients are particularly sore when going down stairs or a slope, during deep squats, or when stretching the calf and Achilles tendon. In bursitis or insertional tendinopathy, “stretching more” is therefore not necessarily the right strategy.

Achilles pain is common in runners, but isolated retrocalcaneal bursitis is less common than Achilles tendinopathy: it most often occurs in the context of an associated insertional condition. It can be seen in distance runners, athletes in jumping sports, those who increase their load suddenly, or people returning to running after a break.

Some studies have found associations between calcaneal morphology, Achilles tendon thickness and the onset of bursitis in runners, but these anatomical factors should not be interpreted as sufficient causes on their own.

Retrocalcaneal bursitis most often results from a combination of several factors related to training, biomechanics, footwear and the morphology of the rearfoot.

Training factors

Sudden increase in mileage or intensity, returning too quickly after a break, a large increase in hill work, more frequent interval or sprint sessions, more plyometric work, a sudden change of surface.

Biomechanical factors

Limited ankle mobility, increased dorsiflexion under load, a recent change in running technique, triceps surae weakness, a reduced capacity of the tendon to tolerate load.

Footwear-related factors

A shoe that is stiff or very high at the back can press directly on the Achilles region (external compression). Heel height and sole stiffness also change the stresses on the tendon: a slight heel raise can temporarily reduce dorsiflexion and therefore reduce insertional compression. A sudden change of shoes, an aggressive heel counter or minimalist shoes in a runner who is not prepared for them are additional risk factors.

Anatomical factors: Haglund’s deformity

Haglund’s deformity is a bony prominence of the posterosuperior part of the calcaneus. It can promote compression of the bursa, insertional tendinopathy and footwear-related pain. However, a bony prominence on imaging does not mean disease: some people have a Haglund morphology without any pain. Imaging must therefore always be correlated with the clinical findings — as with insertional calcifications or thickening of the Achilles tendon, which are also among the anatomical factors.

The main symptom is pain at the back of the heel, often deep, located just above the calcaneus, slightly lateral or medial to the tendon, and sometimes diffuse around the Achilles insertion. Patients typically say: “It hurts deep behind my heel” or “It hurts when I go downhill or when my ankle goes forward”.

Start-up pain may be present after a night’s sleep, a period of sitting, a car journey or a period of inactivity, and ease after a few minutes of walking. Unlike some tendinopathies, however, bursitis pain can remain very sensitive to mechanical compression.

When running, the pain may build gradually, appearing after several kilometres or from the very first minutes, and increase with intensity; accelerations and hills are often particularly provocative. Uphills place heavy demands on the triceps surae and can aggravate the pain; downhills require considerable eccentric control and greater ankle mobility, with dorsiflexion that increases retrocalcaneal compression. The classic calf stretch can also be particularly painful: in a symptomatic patient, aggressive stretching is therefore often best avoided at first.

Clinical examination

The examination looks for the exact location of the pain, tenderness on palpation, swelling, limited mobility, pain on dorsiflexion or on contraction of the triceps surae, involvement of the Achilles tendon, a calcaneal abnormality and footwear-related pain. Palpation must be precise: pain directly on the tendon at its insertion points more towards insertional tendinopathy, whereas deeper pain on either side of the tendon, particularly on compression of the retrocalcaneal region, points more towards bursal involvement — although the distinction is not always possible clinically.

The dorsiflexion test looks for reproduction of the pain by placing the ankle in dorsiflexion (knee straight, knee bent, weight-bearing or open chain), which is particularly suggestive in insertional conditions. The heel raise test (single-leg heel raise) assesses pain, strength, the ability to repeat the movement, asymmetry and movement quality; significant pain may indicate associated involvement of the Achilles tendon.

Surgery is exceptional for isolated bursitis. It may be discussed when symptoms are chronic, functional impairment remains significant, several months of well-conducted conservative treatment have failed, a significant bone abnormality is sustaining the compression, or severe insertional tendinopathy is also present.

Procedures may include bursectomy, resection of the calcaneal prominence, treatment of Haglund’s deformity, tendon debridement, treatment of calcifications, or tendon repair/reattachment depending on the extent of the damage. An endoscopic approach may sometimes be considered for isolated bursitis, with potentially lower morbidity than open surgery. Surgery is not trivial, however (wound-healing problems, infection, persistent pain, nerve injury, adhesions, recurrence, tendon weakness or rupture) and should be reserved for properly selected patients — a Haglund abnormality on imaging is never, on its own, an indication for surgery.

Recent bursitis can resolve favourably within a few weeks thanks to reduced load, footwear adjustments, compression control and progressive rehabilitation. Chronic forms, particularly when associated with insertional tendinopathy or a bone abnormality, may require several months. The disappearance of pain and full recovery of sporting capacity do not always happen at the same time: the region must gradually regain its capacity to withstand compression, traction, high loads and energy storage/release, which takes time even after symptoms have disappeared.

Prevention rests mainly on gradual training progression (avoiding sudden increases in mileage, elevation gain, speed or session frequency) and on regular strengthening of the gastrocnemius, soleus, foot muscles and posterior chain. When managing hills, it is important not to increase volume, speed and elevation gain at the same time, to avoid sudden changes of shoes, and to respect recovery periods between demanding sessions.

With age, the tendon’s capacity to adapt may decrease: for runners over 40, it becomes particularly worthwhile to keep 1 to 2 strengthening sessions a week, including heavy work, single-leg work and appropriate plyometric work. The best way to prepare a tendon to withstand the stresses of running is generally to expose it regularly and gradually to those stresses.