The midfoot is the middle of the foot. It refers to the bones and joints that make up the arch and connect the forefoot (front of the foot including the bones of the toes) to the hindfoot (back of the foot including the ankle bone and the heel bone).
In a midfoot fusion, your foot and ankle orthopaedic surgeon fuses together the different bones that make up the arch of the foot. Fusion eliminates the normal motion that occurs between two bones. Since there is very little movement in the small joints of the midfoot, the function of the foot can be preserved.
Midfoot fusion can involve all of the midfoot joints, but in most cases just one or a few of the joints are fused. The joints of the midfoot do not bend and move like your knee or elbow. They are designed to be relatively stiff to give your foot strength and support your body. Midfoot fusion generally does not produce much noticeable loss of motion because there is fairly little motion to begin with.
The primary goals of midfoot fusion are to decrease pain and improve function. This is achieved by eliminating the painful motion between arthritic joint surfaces and restoring the bones to their normal positions. Other goals include the correction of deformity, returned stability to the arch of the foot, and restored normal walking ability.
The most common reason for midfoot fusion is painful arthritis in the midfoot joints that has not improved with non-surgical treatment. Other common reasons to do a midfoot fusion include too much motion of one or more of the midfoot joints or deformity of the midfoot. Examples of conditions that may result in midfoot deformity include severe bunions, flatfoot deformity, and arthritis. Midfoot fusion also is indicated for certain acute fractures and joint displacement involving the midfoot.
Midfoot fusion should not be performed if there is active infection or if the patient's health is poor enough that the risk of surgery is too high. Conditions such as uncontrolled diabetes and blood circulation problems may make a patient a poor candidate for surgery. Other reasons to not perform midfoot fusion include osteoporosis and poor skin quality. Smoking significantly increases the risk that bones will not fuse.
Successful midfoot fusion depends on complete removal of all joint surfaces (cartilage) and stable fixation of the joints being fused. Residual cartilage can prevent the bones from fusing together. Failure to achieve adequate stability may allow too much motion for fusion to occur.
Typically, your foot and ankle orthopaedic surgeon will make one or two incisions on the top of the foot. The number and length of the incisions is determined by the number of joints to be fused. Your surgeon will pay careful attention to protecting tendons and nerves.
Stability is achieved during midfoot fusion using metal implants such as screws and plates. These are designed to immobilize the joints and allow for the formation of bone across the joint space. Your surgeon may add bone graft material to fill any gaps that might exist between the bones after the cartilage has been removed. This bone graft material may be taken from another location in the patient's body (autograft). It may also come from donated bone (allograft) or from a synthetic material. A combination of these materials may be used.
This surgery may be done as an outpatient (you leave the hospital the same day), but some patients may spend 1-2 nights in the hospital depending on other medical conditions.
After surgery, the midfoot is protected and immobilized to ensure a successful fusion. You will not be able to put weight on the affected foot for 6-12 weeks after surgery. Stitches are typically removed about 2-3 weeks after surgery, and you may be transitioned to a short leg cast at that point. Your surgeon may request X-rays every four weeks to assess progress of the fusion.
Gradually increased weightbearing is allowed as healing progresses. You may initially start weightbearing in a supportive boot or shoe and gradually transition to regular shoes. Physical therapy may be prescribed on a case-by-case basis to help strengthen your limb and help with walking and balance.
All surgeries come with possible complications, including the risks associated with anesthesia, infection, damage to nerves and blood vessels, and bleeding or blood clots.
A major potential complication after midfoot fusion is failure of the bones to fuse (nonunion). Other complications can include over-correction or under-correction of deformity (malunion). There can be problems with wound healing. Prominent plates and screws can be painful and may require removal of the hardware. Injury to nerves on the top of the foot can occur.
Smoking is one of the leading risks for nonunion. Premature weightbearing can also result in failure of the bones to fuse.
The primary goals of fusion for midfoot arthritis are to decrease pain and to improve function. Eliminating the painful motion between the arthritic joint surfaces achieves this, and can improve walking ability.
The midfoot joints on the inside of the foot typically are very stiff and have very little motion. Since there is little motion to begin with, the loss of motion after midfoot fusion surgery is not noticeable and tends to be well-tolerated by patients.
The more mobile joints of the ankle, hindfoot (back of the foot), and forefoot (front of the foot) are not affected by midfoot fusion and will continue to provide motion to the foot.
Time out of work depends on your particular job and how much standing is involved. For more sedentary positions, you may be able to return to work when you are off pain medications, able to safely comply with non-weightbearing restrictions, and able to travel to work while maintaining these same restrictions. For more labor-intensive jobs, it may be at least several months before you can return to work. Your foot and ankle orthopaedic surgeon will talk to you before your surgery and formulate a timeline for returning to work.
A combination of devices can be used, including crutches, walkers, knee-rollers, scooters, and wheelchairs. Physical therapy is used to help assess patient needs and improve mobility and safety. Certain patients may benefit from the assistance provided by a skilled nursing facility or post-operative rehabilitation unit.
It is uncommon for the metal implants to be detectable by airport screening methods. The strength of the metal detector and the amount of metal implants used determine whether hardware from a midfoot fusion will be detected.
Metal implants used for midfoot fusion are not routinely removed. Hardware may need to be removed if there is a failure of the fusion or if infection develops. Painful hardware can be removed once the fusion is healed.
Original article by Mark Berkowitz, MD
Contributors/Reviewers: Wen Chao, MD; Andrew Pao, MD; Erik Freeland, DO
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