A heel spur is defined as a bony outgrowth on the heel bone (calcaneus). The calcaneus is the largest bone in the foot and is located below the anklebone (talus). It plays an important role in weight bearing and movement. Moreover, it serves as an attachment point for two very important anatomical structures, namely:
- The plantar fascia: a thick fibrous sheet attached at the anterior aspect of the calcaneus, spreading from heel to toes
- The Achilles tendon: the strongest tendon in the body that joins the calf muscles to the back of the heel bone.
It is at or near the point of insertion of these two structures that heel spurs usually form.
The heel spur related to the insertion of the plantar fascia, is called the inferior heel spur or sub-calcaneal spur due to its location. If pressed in the weight-bearing position it irritates the surrounding soft tissues, leading to pain. However, it may be painless, either because its direction of growth is such that it does not become a weight-bearing point or due to cessation or absence of inflammation.
On the other hand, the spur forming at the posterior aspect of the calcaneus at the point of insertion of the Achilles tendon is called the posterior heel spur. It is usually seen in Achilles tendonitis (inflammation of the Achilles tendon). The posterior heel spur is often large and can be felt through the skin at the back of the heel.
Location of the heel bone (calcaneum) Posterior heel spur
Why do Heel spurs form?
Heel spurs are thought to result from excessive traction at the point of insertion of the ligaments or tendons in the bone. Inordinate stretching of these structures leads to detachment of the periosteum (the outer covering of the bone). The bone heals itself by forming more bone, leading to spur formation.
Heel spurs are commonly seen in people over 40 years of age. The deterioration that occurs with aging is thought to contribute to spur formation. A research study concluded that subcalcaneal heel spurs are not traction spurs, but are actually formed as a result of degenerative changes in the plantar fascia insertion.
Subcalcaneal heel spurs are found in about 70% of people suffering from plantar fasciitis, especially those who have a long history of the problem. This led to the misconception about these spurs being the cause of plantar fasciitis. However, it is now known that these spurs actually form as a result of plantar fasciitis. This statement is substantiated by X-ray findings which reveal that in about 50% of individuals with heel spurs there is no heel pain or plantar fasciitis symptoms.
Causes and risk factors:
Any factor that leads to excessive pulling of the Achilles tendon or plantar fascia insertions in the heel bone would lead to spur formation, including:
- Tight / stiff plantar fascia (inferior or plantar heel spur)
- Tight Achilles tendon (posterior heel spur)
- Stiff calf muscles
- Excessive physical exertion such as by runners, dancers and military personnel
- Flat or high arch
- Over pronation
- Ill-fitting shoes: Worn out shoes or those providing inadequate support to the heel or foot arch
- Tight shoes pressing at the back of the heel (pump bump) may lead to posterior spur formation
- Acute injury leading to plantar fascia detachment
Sub-calcaneal or inferior heel spur:
Symptoms usually result from the spur impinging on the neighboring soft tissues, leading to injury and inflammation. The bottom of the heel is painful and tender. Pain may develop gradually and may become quite disabling if not attended to properly. It is particularly worse on taking the first steps in the morning or on standing up after a period of rest. It diminishes with activity as the tightened ligament warms up. Walking on hard surfaces or lifting heavy loads exacerbates the symptoms.
Posterior Heel spurs:
There is pain at the back of the heel, made worse when the foot is pushed off the floor during walking. Wearing shoes becomes difficult as there is a prominent bump at the back of the heel.
The overlying skin area is tender on palpation, there may also be callus or corn formation.
The treatment basically consists of providing relief to the inflamed or damaged tissues, alleviating pain and preventing further trauma.
- Rest is mandatory. Do not overexert, limit your activities to the minimum.
- Place ice packs on the area to prevent swelling (in the first couple of days)
- Use anti-inflammatory painkillers.
- Wear supportive and well-fitting shoes with adequate cushioning
- Lose weight if that is a causative factor.
Orthotic insoles act twofold:
Supportive effect: They relieve the pressure and provide cushioning to the tender spot. Arch supports prevent excessive stretching of the plantar fascia when the heel lifts, preventing over stretching of the Achilles tendon.
Therapeutic effect: Orthotic insoles also help to correct any biomechanical, postural faults that may play a role in spur formation.
Stretching exercises to reduce stiffness in the calf muscles and plantar fascia help relieve the pain. Furthermore, exercises to strengthen the leg muscles and ligaments reduce the strain on their bony insertions.
A conservative approach usually works quite well in the management of heel spurs. In non-responding cases, steroid injections or even surgery may be required.
Steroid injections help alleviate local inflammation and its associated symptoms.However, repeated steroid injections weaken the ligaments and are implicated in plantar fat pad atrophy (the fatty tissue that cushions the heel).
Surgery is only rarely required. The surgical approach involves:
- Releasing a part or all of the plantar fascia attachment to the calcaneus; this relieves the tension in the fascia and eliminates the traction force on the heel bone.
- The spur itself may be removed as well.
Surgical treatment is usually very successful. However, if the causative factor is not removed, a heel spur may recur, even after surgical removal.