Lumps on the outside of the foot are typically a result of hammertoes, Tailor’s bunion, tendinitis, trauma, and tumors. These four problems can be treated both conservatively and surgically if needed. This of course depends on the severity of the disease and also the cause of the problem.
Hammertoes or contracted digits is caused by poor posture of the foot. When the foot becomes strained by a flat foot deformity the digits will contract hard against the ground in order to stabilize the foot. This stabilization is the body’s way of maintaining balance and function of the foot. The chronic flexor stabilization that is being used to compensate for the flat feet will then lead to a contracture of the 5th toe. Patient’s will see a hard callus form on the top and outside of the 5th digit where it rubs against the inside of the shoe. The digit may also rotate due to the compensatory stabilization. This is called an adductovarus of the 5th toe which basically means the toe is turned on its side. This can exaggerate the bump on the toe and cause more pain. Conservative measures to treat this problem are orthotics, strapping, padding, and shaving of the callus. Orthotics help to maintain proper foot posture therefore reducing the need for flexor-stabilization. Strapping and padding can help to reduce pressure and friction to the toe thereby reducing the chance for developing a painful callus. Shaving of the callus performed by a podiatrist is commonly utilized since the toe will immediately feel better with a reduction in the hard painful skin. Surgery is considered when all conservative measures fail and pain persists. The procedure is quite simple where removal of a small portion of bone will decrease the deformity and straighten out the toe. The skin can also be stitched in such a way that will result in a de-rotation of the digit, resulting in a straight toe.
A Tailor’s bunion is a result of the 5th metatarsal, which is the bone behind the 5th toe, to move outward secondary to abnormal motion of the foot. Flat feet seems to be the common etiology of all problems of the foot and a Tailor’s bunion is no different. When abnormal foot posture occurs it places strain on the entire foot including the 5th metatarsal. When this strain occurs it causes the 5th metatarsal to deviate towards the outside of the foot causing a large bump just behind the 5th toe. Orthotics, padding, injections can all be utilized to help decrease symptoms. Using wider shoes may also help to alleviate pressure to the bump. Surgery consists of cutting the area of bone just behind the bump and moving the bone over so that the bump is reduced. Shaving of the bump can also be done but its results are less reliable. Placing the 5th metatarsal back into its proper position is the definitive treatment but will only be considered after exhausting conservative therapies.
Tendinitis can occur with the intrinsic muscles of the foot secondary to injury or overuse. A specific muscle which is called the extensor digitorum brevis is positioned in the middle of the foot and a little to the side. When this muscle becomes irritated or injured it can swell and cause a lump on the outside of the foot. This muscle, although small, can cause a lot of symptoms. Pain and swelling are the two main symptoms but nerve pain may also occur. Nerve pain is commonly characterized as burning, tingling, numbing, and shooting in nature. The doctor will determine the severity of the tendinitis and will most commonly immobilize the foot and ankle with a walking boot. After several weeks of walking with the boot the muscle and tendon can heal and physical therapy may be ordered to rehabilitate the foot and ankle. Injections into the muscle may also be considered to help reduce the pain and swelling. Surgery is rarely needed to remedy this problem but an MRI may be ordered in order to check for any major physical damage to the muscle and tendon. Rest, ice, compression, and elevation in combination with the walking boot is the standard treatment used by most doctors.
Trauma such as an ankle sprain can cause damage to all parts of the foot. On the outside of the foot there is a bone called the 5th metatarsal which at its base has a prominence call the styloid process. This area of bone is commonly injured as a result of rolling an ankle. The force that is generated when spraining an ankle can cause strain on the ligaments and tendons that attach to the styloid process of the 5th metatarsal. This force can cause inflammation in the area and possibly a fracture. When this injury occurs pain and swelling can occur to the outside of the foot exaggerating the boney prominence of the styloid process. The doctor will examine both the patient and the appropriate imaging studies in order to determine the problem. Tendinitis will typically be treated conservatively with a walking boot and anti-inflammatories. Fractures, if severe enough, will result in surgery to place the bone back into place to allow for proper function of the foot. If strain or sprain of the foot is the problem then conservative measures will typically fix it.
Benign foot tumors can pop up all over the foot but the most common ones on the side of the foot are ganglion cysts, lipomas, and piezogenic papules. Ganglion cysts are a gelatinous filled cyst that is typically orientated over a joint space. These cysts can be painful but most are not. The cyst can range in size and may remain in the foot for a long time without any symptoms. The doctor will typically try to drain the cyst using a fine needle but surgical excision may be necessary depending on the severity of the problem. Lipomas are also a common benign cyst that is a result of an abnormal collection of fatty tissue. This collection can be very large but surprisingly not painful. Severity of the problem will steer the course of treatment with surgery being a last resort option. Piezogenic papules are small little bumps that appear on the side of the heel that are typically not painful. These lesions are benign and develop because of a defect in the fascia around the heel. Fatty tissue will penetrate through defects in the fascia and will result in a tiny bump on the outside of the heel. The bumps will be accentuated when weight bearing since the fatty infiltrates are pushed out even more.