Adult Acquired Flatfoot Deformity
A Patient's Guide to Adult-Acquired Flatfoot Deformity
IntroductionAdult acquired flatfoot deformity (AAFD) is a painful condition resulting from the collapse of the longitudinal(lengthwise) arch of the foot. As the name suggests, this condition is not present at birth or during childhood. It occurs after the skeleton is fully matured.
This guide will help you understand
AnatomyWhat parts of the foot are involved?
The skeleton of the foot begins with the talus, or ankle bone, that forms part of the ankle joint. The two bones of the lower leg, the large
Just down the foot from the ankle is a set of five bones called tarsal bones that work together as a group. These bones are unique in the way they fit together. There are multiple joints between the tarsal bones. When the foot is twisted in one direction by the muscles of the foot and leg, these bones lock together and form a very rigid structure. When they are twisted in the opposite direction, they become unlocked and allow the foot to conform to whatever surface the foot is contacting.
The tarsal bones are connected to the five long bones of the foot called the metatarsals. The two groups of bones are fairly rigidly connected, without much movement at the joints.
The large Achilles' tendon is the most important tendon for walking, running, and jumping. It attaches the calf muscles to the heel bone to allow us to rise up on our toes. The posterior tibial tendon attaches one of the smaller muscles of the calf to the underside of the foot. This tendon helps support the arch and allows us to turn the foot inward. Failure of the posterior tibial tendon is a major problem in many cases of adult-acquired flatfoot deformity (AAFD).
The toes have tendons attached that bend the toes down (on the bottom of the toes) and straighten the toes (on the top of the toes). The anterior tibial tendon (tibialis anterior) allows us to raise the foot. Two tendons run behind the outer bump of the ankle (called the lateral malleolus) and help turn the foot outward.
Many small ligaments hold the bones of the foot together. Most of these ligaments form part of the joint
CausesWhat causes adult-acquired flatfoot deformity?
There are multiple factors contributing to the development of this problem. Damage to the nerves, ligaments, and/or tendons of the foot can cause subluxation (partial dislocation) of the subtalar or
Dysfunction of the posterior tibial tendon has always been linked with adult-acquired flatfoot deformity (AAFD). The loss of active and passive pull of the tendon alters the normal biomechanics of the foot and ankle. The reasons for this can be many and varied as well. Diabetes, high blood pressure, and prolonged use of steroids are some of the more common causes of adult-acquired flatfoot deformity (AAFD) brought on by impairment of the posterior tibialis tendon. Overstretching or rupture of the tendon results in tendon and muscle imbalance in the foot leading to adult-acquired flatfoot deformity (AAFD).
Rheumatoid arthritis is one of the more common causes. About half of all adults with this type of arthritis will develop adult flatfoot deformity over time. In such cases, the condition is gradual and progressive.
Obesity has been linked with this condition. Loss of blood supply for any reason in the area of the posterior tibialis tendon is another factor. Other possible causes include bone fracture or dislocation, a torn or stretched tendon, or a neurologic condition causing weakness.
SymptomsWhat does the condition feel like?
At first you may notice pain and swelling along the medial (big toe) side of the foot. This is where the posterior tibialis tendon travels from the back of the leg under the medial ankle bone to the foot. As the condition gets worse, tendon failure occurs and the pain gets worse. Some patients experience pain along the lateral (outside) edge of the foot, too.
DiagnosisHow do doctors diagnose the problem?
The history and physical examination are probably the most important tools the physician uses to diagnose this problem. The wear pattern on your shoes can offer some helpful clues. Muscle testing helps identify any areas of weakness or muscle impairment. This should be done in both the weight bearing and
A very effective test is the single heel raise. You will be asked to stand on one foot and rise up on your toes. You should be able to lift your heel off the ground easily while keeping the calcaneus (heel bone) in the middle with slight inversion (turned inward).
X-rays are often used to study the position, shape, and alignment of the bones in the feet and ankles. Magnetic resonance (MR) imaging is the imaging modality of choice for evaluating the posterior tibial tendon and spring ligament complex.
There are four stages of adult-acquired flatfoot deformity (AAFD). The severity of the deformity determines your stage. For example:
TreatmentWhat treatment options are available?
Nonsurgical TreatmentConservative (nonoperative) care is advised at first. A simple modification to your shoe may be all thatâ??s needed. Sometimes purchasing shoes with a good arch support is sufficient. For other patients, an off-the-shelf (prefabricated) shoe insert works well.
The orthotic is designed specifically to position your foot in good alignment. Like the shoe insert, the orthotic fits inside the shoe. These work well for mild deformity or symptoms.
Over-the-counter pain relievers or antiinflammatory drugs such as ibuprofen may be helpful. If symptoms are very severe, a removable boot or cast may be used to rest, support, and stabilize the foot and ankle while still allowing function. Patients with longer duration of symptoms or greater deformity may need a customized brace. The brace provides support and limits ankle motion. After several months, the brace is replaced with a foot orthotic.
A physical therapy program of exercise to stretch and strengthen the foot and leg muscles is important. The therapist will also show you how to improve motor control and proprioception (joint sense of position). These added features help prevent and reduce injuries.
SurgeryWhen conservative care fails to control symptoms and/or deformity, then surgery may be needed. The goal of surgical treatment is to obtain good alignment while keeping the foot and ankle as flexible as possible.
The most common procedures used with this condition include arthrodesis (fusion), osteotomy (cutting out a wedge-shaped piece of bone), and lateral column lengthening. Lateral column lengthening involves the use of a bone graft at the calcaneocuboid joint. This procedure helps restore the medial longitudinal arch (arch along the inside of the foot).
It's not clear yet from research evidence which surgical procedure works best for this condition. A combination of surgical treatments may be needed. It may depend on your age, type and severity of deformity and symptoms, and your desired level of daily activity.
RehabilitationWhat should I expect as I recover?
Nonsurgical RehabilitationPain relief and improved function are the two main changes patients report with effective treatment. It's not clear yet if these measures prevent or stop the foot deformity from occurring or getting worse. Some short-term studies (one year) show good results with mild to moderate adult-acquired flatfoot deformity (stages I and II deformity) using orthotic support, foot orthotics, and physical therapy.
Any sign of increasing deformity may be an indication that surgery is needed. Careful monitoring over time is needed to assure the best timing for surgery. Waiting too long can mean a less successful surgical result.
After SurgeryPostoperative care may depend on the type of surgery you have. After a tendon transfer and/or osteotomy, you will be in a cast or removable brace for six weeks. In most cases, you won't be allowed to put weight on the foot during this time. This is especially true if you've had a tendon transfer or bone fusion.
A physical therapist will help you progress from nonweight-bearing to full weight-bearing status. You will probably be wearing a removable boot and starting range of motion exercises. Strengthening exercises can begin when the tendon transfer has healed. At this point you may still have some painful symptoms.
Significant improvement occurs gradually over a four-to-six month period of time. During that time, you will progress in your exercise program. The removable boot will be replaced with a foot orthosis and lace-up shoes. For those patients who have a fusion, you can expect some stiffness and loss of motion in the foot and/or ankle. The amount and location of the stiffness depends on which bones were fused together.
Studies show that long-term results of just reconstructing the posterior tibial tendon have been disappointing. As much as a 50 per cent failure rate has been reported. This is probably because of the complexity of soft tissue interactions needed to maintain structural integrity of the foot. Reconstructing the spring ligament complex or using an osteotomy to lengthen the lateral side of the foot along with a tendon transplant is more likely to restore more normal foot and ankle movement with better results.
Prolonged swelling and discomfort are not uncommon even six to 10 months after the surgery. Standing on your feet for a long time or walking long distances can also cause foot pain or discomfort.
*Disclaimer:*The information contained herein is compiled from a variety of sources. It may not be complete or timely. It does not cover all diseases, physical conditions, ailments or treatments. The information should NOT be used in place of visit with your healthcare provider, nor should you disregard the advice of your health care provider because of any information you read in this topic.
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