An Article By Cecilia Brennan, Podiatrist – New Step Podiatry.
Pain on the Outside of Your Foot? Understanding Lateral Foot Pain
Pain on the outside of the foot can be frustrating, particularly when there hasn’t been an obvious injury.
While heel and arch pain receive plenty of attention, lateral foot pain, meaning pain along the outside of the foot, can come from several different structures. Tendons, joints, bones, bursae and nerves are all found within a relatively small area, which means two people with pain in almost the same location may have very different problems.
Some causes of outside foot pain develop gradually due to repeated loading rather than a single injury. You might first notice discomfort after a long walk, during exercise or after spending more time than usual on your feet. In other cases, the pain may keep returning without an obvious reason.
Below are six possible causes of pain on the outside of the foot that we commonly consider during a podiatry assessment.
1. Peroneal Tendinopathy: Pain Along the Outside of the Foot and Ankle
What is peroneal tendinopathy?
The peroneal tendons run down the outside of the lower leg and behind the outer ankle bone before continuing into the foot.
The peroneus brevis tendon attaches to the base of the 5th metatarsal on the outside of the foot. The peroneus longus tendon continues underneath the foot before attaching around the inside of the midfoot.
Peroneal tendinopathy occurs when one or both tendons become painful and their ability to tolerate load is reduced.
Depending on which part of the tendon is affected, pain may be felt behind the outside ankle, below the ankle or further along the outside of the foot. It may feel like an ache or tenderness and can become more noticeable with walking, running, hills or prolonged activity.
Why does peroneal tendon pain happen?
Peroneal tendinopathy is often associated with repeated loading of the tendons. An increase or change in walking, running, sport or exercise can place more demand on the tendons than they are used to.
Foot posture and biomechanics can also influence how much work the peroneal tendons need to do. People with higher arches may naturally place more load along the outside of the foot. The peroneal tendons may need to work harder to stabilise the foot and resist it rolling outwards, particularly during walking and running.
People with flatter or more pronated feet can also develop peroneal tendon problems. As the foot rolls inwards and changes position during weight-bearing, the peroneal tendons may work differently or be placed under increased demand as they help control and stabilise the foot and ankle.
Previous ankle sprains or chronic ankle instability can further increase the workload on the peroneal tendons, as they play an important role in controlling side-to-side movement and helping protect the ankle from rolling.
Footwear, changes in walking or running surfaces, and a sudden increase in activity can also contribute. Often, there is not one single cause, but a combination of foot structure, movement and increased load.
2. Cuboid and Calcaneocuboid Joint Pain
What is cuboid pain?
The cuboid is a small but important bone on the outside of the midfoot. It sits between the heel bone (calcaneus) and the bases of the 4th and 5th metatarsals. It is sometimes described as a keystone of the lateral longitudinal arch, helping form and support the arch that runs along the outside of the foot.
The peroneus longus tendon also runs underneath the cuboid through a groove in the bone before crossing under the foot. This means the cuboid has an important relationship with both the structure of the lateral foot and the way the foot functions during walking.
Pain involving the cuboid region may be felt along the outside of the midfoot, but it is also commonly felt underneath the outer part of the foot. There may be a fairly localised tender area around the cuboid or calcaneocuboid joint, with pain becoming more noticeable when standing, walking or pushing off through the foot.
One possible cause is cuboid syndrome, a term used to describe pain and altered function around the cuboid and its surrounding joints and soft tissues. However, not all pain around the cuboid is cuboid syndrome.
The calcaneocuboid joint can also develop osteoarthritis, where degenerative changes within the joint can cause pain, stiffness and reduced movement. Osteoarthritis may develop following a previous injury or alongside longer-term changes in foot structure and function.
Why can the cuboid or calcaneocuboid joint become painful?
The cuboid forms an important part of the lateral column of the foot and is exposed to load every time we stand, walk and push off.
Foot posture and biomechanics can influence how much pressure and movement occur through this area. People with higher arches may place greater pressure through the outside of the foot, increasing load through the cuboid and surrounding joints. Other foot postures and movement patterns can also alter the forces passing through the lateral column.
Because the peroneus longus tendon passes directly underneath the cuboid, increased demand on this tendon may also contribute to symptoms around the plantar and lateral cuboid region.
Previous foot or ankle injuries, repetitive loading, changes in activity and osteoarthritis of the calcaneocuboid joint can all contribute to pain in this area. Sometimes more than one structure is involved, which is why accurately identifying the source of lateral midfoot pain is important.
3. 5th Metatarsal Stress Injuries
What is a 5th metatarsal stress injury?
The 5th metatarsal is the long bone that runs along the outside of the foot towards the little toe.
Although 5th metatarsal fractures can occur suddenly following an injury, problems with this bone can also develop gradually.
A bone stress reaction occurs when repeated loading begins to exceed the bone’s ability to recover and adapt. If the loading continues, a stress reaction can potentially progress to a stress fracture.
Pain is often quite localised along the 5th metatarsal. Initially, you may only notice pain during or after activity. If the problem progresses, it may become painful during normal walking and, in more significant cases, at rest.
Why do 5th metatarsal stress injuries happen?
Bone stress injuries occur when the amount of repetitive load being placed on a bone exceeds its current ability to recover and adapt.
A sudden increase in walking, running or other weight-bearing exercise can contribute. Foot structure, biomechanics, footwear, training surfaces and the way pressure is distributed through the foot may also affect the load placed on the 5th metatarsal.
Bone health is also important. Depending on the individual, factors such as nutrition, energy availability, vitamin D, hormonal changes and bone density may need to be considered.
Persistent, highly localised pain over the 5th metatarsal should be assessed, particularly if it is becoming more painful with normal walking.
4. 4th and 5th MTPJ Pain: Pain Near the Outside of the Ball of the Foot
What is MTPJ pain?
The metatarsophalangeal joints (MTPJs) are the joints where the long metatarsal bones meet the toes.
Pain around the ball of the foot is often associated with the central metatarsals or big toe, but the 4th and 5th MTPJs on the outside of the forefoot can also become painful.
The pain may feel aching, tender or bruised and can be particularly noticeable when pushing off during walking or after spending longer periods on your feet.
Pain can come from inflammation of the joint lining (synovitis) or irritation of the joint capsule, the sleeve of tissue surrounding the joint. Repeated loading can also affect the supporting tissues underneath the joint, including the plantar plate, which helps keep the toe stable. These problems can cause pain around or beneath the joint without necessarily meaning that you have arthritis.
Arthritis is another possible cause. It can affect several parts of the joint, including the cartilage, underlying bone and joint lining.
Why do the 4th and 5th MTPJs become painful?
Every time you take a step, load is transferred through the metatarsal heads and MTPJs.
Pain can develop when one or more of these joints are repeatedly exposed to more pressure than they are comfortably tolerating.
Foot shape, toe position, the relative position of the metatarsals and the way you walk can all influence how pressure is distributed across the forefoot.
Footwear may also contribute, particularly when shoes are narrow, poorly cushioned or place additional pressure around the outside of the forefoot.
5. Pain Between the Metatarsals: Bursae, Ligaments and Nerves
What causes pain between the metatarsals?
There are several small structures between the metatarsal bones that can contribute to pain in the forefoot.
The intermetatarsal bursae are small fluid-filled sacs that help reduce friction between nearby structures. When a bursa becomes irritated and inflamed, this is known as intermetatarsal bursitis.
The metatarsal heads are also connected by the deep transverse metatarsal ligament, a strong ligament that helps stabilise the forefoot and maintain the relationship between the metatarsal heads. The interdigital nerves pass beneath this ligament on their way towards the toes.
Pain from this region is usually felt between or around the metatarsal heads and may spread towards the nearby toes. When the structures between the 4th and 5th metatarsals are involved, symptoms may be felt towards the outside of the forefoot.
Symptoms can include aching, burning, tenderness or a feeling of pressure underneath the foot. Some people describe feeling as though there is a pebble, lump or something underneath the ball of their foot. Tight shoes or squeezing the forefoot may make symptoms more noticeable.
Why can pain develop between the metatarsals?
Repeated pressure and compression through the forefoot can irritate the structures between the metatarsals.
Footwear that is tight or narrow through the forefoot may increase compression, while prolonged walking, running or other repetitive weight-bearing activities can increase load through the area.
Foot structure and biomechanics can also influence how pressure is distributed across the metatarsal heads. Changes in the position or movement of the metatarsals can increase stress on the bursae, ligaments and surrounding soft tissues.
Because the bursa, deep transverse metatarsal ligament and interdigital nerve are located very close together, symptoms can overlap. Intermetatarsal bursitis can also occur alongside irritation or thickening of an interdigital nerve, commonly referred to as a Morton’s neuroma.
6. Sural Nerve Irritation: Burning, Tingling or Sensitivity Along the Outside of the Foot
What is sural nerve irritation?
The sural nerve is a sensory nerve that travels down the back and outside of the lower leg, passes behind the outer ankle bone (lateral malleolus) and continues along the outside of the foot. It provides sensation to the outer ankle and part of the lateral foot, extending towards the 5th toe.
Because it is a sensory nerve, irritation of the sural nerve tends to feel different from typical muscle, tendon or joint pain. Symptoms may include burning, tingling, pins and needles, shooting pain, numbness or increased sensitivity along the outside of the ankle or foot. Even light touch or pressure from footwear may sometimes feel uncomfortable.
Why can sural nerve pain happen?
The sural nerve can become compressed, irritated or entrapped at different points along its course. Importantly, the site where the nerve is being irritated does not have to be the same place where the symptoms are felt. Entrapment further up the nerve, such as around the calf or behind the outside of the ankle, can produce pain or altered sensation further along the nerve’s pathway and into the outside of the foot.
Previous ankle sprains or other injuries may contribute through traction, swelling, scar tissue or changes in the tissues surrounding the nerve. The nerve can also be affected by local compression, tight footwear or braces, repetitive activity, or other structures placing pressure on the nerve.
Because pain along the outside of the foot can also come from the peroneal tendons, 5th metatarsal and other nearby structures, recognising symptoms that have a burning, tingling, shooting or sensitive quality can be an important clue that a nerve may be involved.
Why Does the Outside of My Foot Hurt When I Walk?
There isn’t one single cause of pain on the outside of the foot.
Two people can point to almost exactly the same location but have pain arising from completely different structures. One person’s pain may be coming from a tendon, while another person’s symptoms may involve a joint, bone, bursa or nerve.
This is why the exact location of your pain, how it started, what the pain feels like and what makes it better or worse are important.
Your foot structure and the way you move can also influence where pressure is distributed when you walk. If one area of the foot is repeatedly taking more load than it can tolerate, this may contribute to ongoing or recurrent symptoms.
When Should I See a Podiatrist for Pain on the Outside of My Foot?
If pain on the outside of your foot is persistent, worsening, keeps returning or is starting to limit how far you can comfortably walk or exercise, it is worth having it assessed.
It is particularly important to seek assessment if there is significant swelling, very localised bone pain, pain at rest or difficulty comfortably bearing weight, as further investigation may be required.
How Can a Podiatrist Help With Lateral Foot Pain?
At New Step Podiatry in Canberra, we assess lateral foot pain to determine which structure is causing your symptoms and why that area may be under increased stress.
A podiatry assessment may include examining the location of your pain, assessing your foot and ankle movement, muscle strength and function, reviewing your footwear and looking at the way you stand and walk. Where appropriate, gait and plantar pressure analysis can provide additional information about how pressure is being distributed through your feet.
Treatment for pain on the outside of the foot will depend on the structure involved and the factors contributing to it. This may include temporarily modifying aggravating activities, footwear changes, padding or offloading, taping or bracing, strengthening and rehabilitation exercises, orthotics or other strategies to alter load through the painful area.
If we suspect a 5th metatarsal stress injury or another condition requiring further investigation, imaging may be recommended.
The important part is identifying what is actually causing your lateral foot pain rather than treating all pain on the outside of the foot in the same way.
If you’ve been experiencing persistent pain along the outside of your foot, a podiatry assessment can help identify the likely cause and develop a treatment plan to help you return to comfortable walking and activity.
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