Occurring when the arch that runs along the sole of the foot fails to develop, flat foot (pes planus) is a common condition in children, especially those under the age of five. If the arch doesn’t develop later or the problem continues or develops for other reasons during adulthood, surgery may be necessary to provide the necessary support during daily movements. The Maxwell-Brancheau arthroereisis (MBA) implant is one the FDA-approved corrective devices that may restore the natural arch of the affected foot.
What is the MBA Implant?
The Maxwell-Brancheau arthroereisis implant is an artificial implant made of durable materials that include titanium, plastic, and stainless steel. It’s an arthroereisis implant, meaning that the device is meant to be inserted within a small, bony canal that goes into the ankle just under the talus ankle bone, an area referred to as the sinus tarsi. The implant is available in five different sizes (6, 8, 9, 10, and 12 millimeter diameters).
How is MBA Implant Surgery Performed?
The size of the implant used will depend on how much correction is necessary and factors such as the patient’s height and weight. During surgery, usually performed under general anesthesia, the MBA implant will be placed within the sinus tarsi to restore the foot’s natural arch or create an arch if one didn’t exist at all previously.
Essentially an “internal orthotic,” the implant itself has a smooth surface at the point where it rests against the bones in the foot to prevent irritation and inflammation of nearby tissues with normal foot movements. An X-ray may be taken after the insertion of the implant to confirm that it has been properly placed.
What Happens After Implant Surgery?
There will be an initial healing period following the surgery, as is the case with any procedure to correct flat foot. Most patients are able to walk again without too much pain within a day or two after the procedure. A walking boot or other assistance device may be used to provide support. Medications may be prescribed to minimize any temporary discomfort.
During initial recovery, the foot should be elevated. The surgical site may remain numbed for 6-8 hours to further minimize discomfort. Patients may place ice on the surgical site to reduce inflammation from the procedure. The use of ice applications should be restricted to 15-20 minute periods.
Some post-op physical therapy may be recommended to allow the patient to become fully comfortable with their newly restored arch. It’s still important to wear comfortable, supportive shoes and be mindful of activities that may place excessive strain on the heel. Full recovery from implant surgery typically takes 4-6 weeks.
How Effective Are MBA Implants?
According to a study referenced in the Journal of Foot Ankle Surgery involving cadaver limbs, better results are typically seen when larger implants are used. There are no standard guidelines for selecting the appropriately sized implant to use during the procedure. The size recommended will depend on how much of the heel motion will need to be controlled or restored. Researchers note that choosing the correct implant size may increase the odds of success with the procedure.
When is the MBA Implant Considered?
An MBA implant is considered when other remedies aren’t effective or if the deformity is severe and debilitating. In some cases, an implant is recommended when flat foot is contributing to shin, knee, hip, and even lower back pain. This usually occurs because of issues with alignment that affect other muscles and tendons.
The MBA implant is generally used to correct what’s termed “flexible flat foot” where the foot is flat when standing and the arch returns when not the patient isn’t standing. However, it may be recommended for other types of flat foot depending on the circumstances involved.
Surgery involving the use of the MBA implant may also be considered if symptoms of flat foot become progressively worse to the point where gait is affected or if it becomes difficult for a patient to maintain balance, stand, walk, or run. Such symptoms may include:
- Pain that’s aggravated with activity
- Swelling around the heel or arch that makes wearing corrective shoes painful
- Rolling in the foot or ankle when walking
Flat foot may be genetic or develop later in life as a complication of conditions such as arthritis, diabetes, or stroke. Surgery is rarely the first attempt at correcting the deformity. If conservative treatments involving medications, calf stretching and other exercises, and the use shoe inserts and other orthotics aren’t effective, the Maxwell-Brancheau arthroereisis implant may be recommended as an alternative to surgical lengthening or realignment of the heel bone (calcaneal osteotomy), another surgical procedure for flat foot.