AUTHOR: Marc Mitnick DPM
REVIEWED BY: Podiatric Medical Review Board
home --> bone spur
osteophyte or exostosis
WHAT IS A BONE SPUR
This condition is an overgrowth of bone. This problem is not unique to the foot but it does occur quite commonly in the foot and ankle. Spurs can and do occur anywhere in the skeletal system. They are also commonly known as osteophytes or exostosis.
An exostosis can be large or small, it may or may not be painful. Over the years when I have ordered x-rays for patients for other problems, and I will point out to them that they have a bone spur of significance and in most cases the patient will relate to me that they have never had an issue in that part of the foot or ankle.
In the foot at least, an exostosis that is large enough, usually on the top or side of the foot, or on the toes, can be felt through the skin as a protrusion or hard lump.
WHAT CAUSES A BONE SPUR
An exostosis is an overgrowth of bone most commonly seen at a joint (the place where two bones come together and allow for movement).
ABNORMAL MOTION AT THE LEVEL OF A JOINT-if the movement of the joint is not optimal, over time, there will be bone erosion and formation of osteophytes.
EXCESSIVE TENSION ON A BONE FROM A TENDON ATTACHMENT-the "pulling" of the tendon on the bone may cause the bone to form excess growth.
TRAUMA-as severe as a fracture or multiple traumas to the same area, may end up causing osteophytes to form.
EVERY DAY "WEAR AND TEAR"-over the course of years, to an area of bone will cause bone to once again, over produce to form a spur.
BONE DISEASES-such as osteomyelitis (bone infection) and Charcot foot may also cause excess bone to form.
NORMAL AGING-will also cause osteophytes to form.
BONE SPUR SYMPTOMS
Most adults have osteophytes somewhere in their body. The good news is just because you have an exostosis does not necessarily mean you will have pain nor does it mean anything need be done about it.
PAIN-pain is usually the result of the exostosis pressing on a nerve, tendon, muscle, or getting in the way of the function of a joint. The pain can range from mild discomfort, to severe pain every time the patient takes a step. The pain can quickly disappear once the patient is at rest, or the pain can persist even beyond activity.
STIFFNESS-if the spur limits the motion of a joint, there will be stiffness as the joint is not able to go through its full range of motion
INFLAMMATION-such as mild swelling and redness over the area.
LOSS OF FUNCTION-if a piece of the spur breaks off and lodges in the joint, the affected joint will "lock" and it will be very painful to try and move the joint.
Look at the x-rays below. These are typical bone over growths seen in the foot.
Spurring in the toes will generally cause corns or even inflame the surrounding tissue causing a bursitis
A corn in between the toes (soft corn) more often than not is the result of an exostosis on one toe pressing into the adjacent toe, especially in closed shoes, thus causing excessive pressure and the formation of a corn. The most common cause is due to overlapping toes.
BONE SPUR ON TOP OF FOOT
A small red swollen area either on the top of one of the toes especially the fifth toe may often be the result of bone overgrowth which is irritated by shoe wear and causes a bursitis
Pain on the top portion of the big toe joint commonly known as hallux rigidus (hallux limitus or 1st metatarsal bone spur) is the result of exostosis formation usually on both the first metatarsal bone and the base of the proximal phalanx (the base of the big toe). Take a look at the full foot x-ray below and note the red arrow. The overgrowth of bone that has occurred above the level of the great toe joint creates pain any time the patient attempts to bend the big toe. Even simple walking will create pain. This pain occurs either in or out of shoes. Surprisingly, the foot will tend to hurt more out of shoes because without a rigid sole of a shoe, the big toe is forced to bend more when walking, thus creating more pain.
In this particular instance the big toe bone spur is so bad that the exostosis has actually fractured. This is evidenced by the green arrow.
Bone spurs on the top of the foot can usually be palpated (felt) due to the fact that the skin is very thin on the top of the foot and there is virtually no muscle there either. Note the yellow arrow. That is a bone spur at the talo-navicular joint on top of the foot. This could create pain just in front of the ankle joint.
The most famous exostosis on the foot is probably the heel spur. Heel bone spurs can occur both on the bottom of the heel and the back of the heel (insertional Achilles tendon bone spur) although the classic heel spur is the one occurring on the bottom of the heel as noted by the blue arrow.
image of bone spurs on top of foot
Lastly, perhaps the most serious side effect from a bone spur on the foot is the formation of an ulcer. Since this condition is an over growth of bone, it can create friction or pressure points against the shoe. In individuals who are either diabetic or have circulation compromised feet, the skin between the spur and the shoe may break down and form an ulcer.
BONE SPUR ON SIDE OF FOOT
In most instances a bone spur on the side of the foot will be aggravated by shoe pressure.
The most common bone spur on the side of the foot is a bunion which is an enlargement of bone just behind the big toe. The actual bone spur is from a combination of pressure against the first metatarsal which causes the bone to enlarge, as well as movement of the first metatarsal away from the second metatarsal, further enlarging the bone spur.
A similar situation is seen on the outside of the foot on the fifth metatarsal head. This is known as a Tailors bunion.
Some bone spurs on the side of the foot are not actual bone spurs but are accessory bones which are small round bones that approximately 20-25 percent of the population exhibit.
A supposed bone spur on the inside of the foot may actually be an accessory navicular which is an accessory bone adjacent to the navicular bone.
Similarly a purported bone spur on the outside of the foot, may be an os peroneum which is an accessory bone that is usually found within the peroneus longus tendon that travels down the outside of the foot near the fifth metatarsal base.
Speaking of the fifth metatarsal base, occasionally people will complain of outside pain in that area. Although not a true bone spur, some individuals exhibit a large "flare" at the base of the fifth metatarsal which will cause pain in a narrow shoe. In many cases, people who wear sandals, where the strap covers the fifth metatarsal base will have pain simply from the strap pressing into the fifth metatarsal base.
TREATMENT OF BONE SPURS
CHANGING TO A CONSERVATIVE SHOE-to a less restrictive (translated: less stylish) which takes pressure off the spur. Generally, a laced oxford which offers a high and wide toe box is the most comfortable shoe.
ORTHOPEDIC PADDING-over the affected area will keep shoe pressure off the area and relieve the pain.
CORTISONE INJECTIONS-into the inflamed area can be very useful in eliminating the pain. Sometimes more than one injection is necessary.
ANTI-INFLAMMATORY MEDICATION-both prescription and over the counter (for short durations) may be helpful.
PHYSICAL THERAPY-by a Physical Therapist may help reduce the symptoms.
HEAT AND ICE THERAPY-done at home may also be useful.
SURGERY-as it relates to the foot, bone spur formation may quite possibly be the number one reason people seek foot surgery. If conservative care does not alleviate the pain, in most cases surgically removing the bone spur will. Bones spurs particularly on the toes may be removed with minimal incision procedures. In these cases the toes are anesthetized with lidocaine (local anesthesia). A very small incision is made above the bone spur and using a high powered drill, the exostosis is removed. The procedure requires one or two sutures and recovery, barring any complications, is usually very quick.
In cases where an ulcer has formed, in many instances, the underlying exostosis will have to be surgically removed in order to get the ulcer to close.
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