Posterior Tibial Tendon Dysfunction and Adult-Acquired Flatfoot

The posterior tibial tendon is one of the major supporting structures of the foot.  It functions to help add stability to the arch, and assists in normal gait fuction.  Posterior tibial tendon dysfunction is a condition caused by changes in the tendon, leading to a loss of this stability and a flattening of the arch of the foot. 

Posterior tibial tendon dysfunction, or PTTD, is often referred to as “adult-acquired flatfoot”.  This is because PTTD is the most common cause of flatfootedness in adults.  The condition can occur in one or both of the feet.  PTTD is usually a progressive condition, meaning that the arch will continue to flatten and the symptoms will worsen over time if not addressed. 

PTTD is most often attributed to overuse of the tendon, although there may be other contributing factors.  Inflammatory arthropathies such as rheumatoid arthritis can contribute to it’s development, as well as injuries to the foot and ankle, or other bony abnormalities of the foot. 

Symptoms of PTTD may include pain, swelling, or redness around the posterior tibial tendon.  This is located on the medial side of the foot and ankle.  As the condition progresses, pain may also develop in the arch of the foot or the ankle.  Arthritis of the joints of the foot and ankle may develop overtime, leading to worsening symptoms. 

The diagnosis of PTTD or adult-acquired flatfoot is largely a clinical diagnosis.  On physical examination, the pain may be localized to one or more of the effected areas.  The arch of the foot will usually appear flattened, and the forefoot may be abducted, or shifted laterally, in relation to the rearfoot.  This is known as the “too many toes” sign, as the examiner will be able to see more of the toes from behind the patient on the affected side than on the non-affected side.  Patients with PTTD may also have a difficult time rising to their toes on the affected side, especially when asked to rise to their toes using only one leg. 

X-rays are typically taken to rule out other potential causes of pain, such as arthritis, fractures, or dislocations.  They also serve as a baseline study to monitor the progression of the foot and ankle, should the symptoms worsen over time.  If a tear of the tendon is suspected, an MRI may be useful in determining the extent of the tendon tear. 

Treatment for PTTD will typically begin with conservative treatment.  This will involve things such as orthotics and other types of braces, anti-inflammatroy medications, and periods of rest and ice.  For patients with a painful flare-up of symptoms, a period of immobilization may be beneficial.  This would involve the use of a cast or immobilizing cast boot to protect the foot and ankle.  If some of the symptoms are related to arthritis of the nearby joints, such as the subtalar joint or ankle, a cortisone injection may be beneficial to relieve some of the pain. 

Surgical intervention may be warranted if conservative treatment fails, or is deemed to not be helping enough in managing pain and function.  Surgical treatment will vary depending on the symptoms, and the extent of foot and ankle deformity.  For patients with symptoms isolated to the tendon and not involving the surrounding joints, the foot and ankle surgeon may recommend “cleaning up the tendon” and restoring as much normal anatomy as possible to the tendon.  This is a procedure that is as minimally invasive as possible for these types of complaints.

For patients with more advanced pathology, a variety of approaches may be used.  Surgical techniques may involve repositioning the calcaneus (heel bone), shifting tendons in the foot, and repositioning the bones and joints of the midfoot to recreate a more functional foot.  Of course, these methods can vary greatly between patients, and depend on a number of factors.  Factors such as the patient’s lower extremity anatomy, age, weight, and overall health status should be considered in the pre-operative work-up. 

Surgical reconstruction of the foot and ankle is not without risk, and a thorough conversation should be had between the patient and doctor before surgery can be considered.  Time off of work, time to heal, and post-operative expectations of all parties should be discussed.  

Central Florida Foot & Ankle Center, LLC 
101 6th Street N.W. 
Winter Haven, FL 33881 
Phone: 863-299-4551 
www.FLFootandAnkle.com

Predislocation Syndrome

Metatarsalgia is a general term that is used to refer to pain in the metatarsal heads of the foot. This is the area of the metatarsal that forms the proximal half of the metatarsal-phalangeal (MTP) joints, which are the joints that connect the toes to the rest of the foot.  Pain underneath the second metatarsal head is a common clinical presentation. 

Pain in the second metatarsal most commonly occurs in the presence of hallux limits.  Hallux limitus is a condition in which the first metatarsophalangeal joint (the joint that connects the big toe to the rest of the foot) does not have the appropriate amount of motion required for normal function.  When there is not enough motion available in the first MTP joint, the ground reactive forces are transferred to the lateral, smaller MTP joints.  Most often, it is the second MTP joint that takes the brunt of this force.

If the second toe has a hammer digit deformity, in which the joints of the small toe remain contracted, it can exacerbate the problem.  When a hammer toe is present, the metatarsal head is pointed down towards the ground, or plantarflexed.  This plantarflexed position of the metatarsal adds to the amount of force.  Equinus deformities, in which the ankle joint is tight, can also contribute to the problem by placing additional pressure on the forefoot.  The pain will be especially great when the patient walks down stairs, as they lead with their toes. 

When this second metatarsalgia is present for a long period of time, a condition known as predislocation syndrome may occur.  This is most commonly described in the second toe, though it may be seen in any of the lesser digits.  Predislocation syndrome occurs when the plantar plate, which is a portion of the joint capsule, becomes damaged.  This damage can attenuate, or thin out, the structure.  This attenutation can lead to joint instability, and can cause the second toe to end up pointing upwards and medially or laterally.  Thus, the condition is also sometimes referred to as a crossover toe deformity, as the second toe may overalp the first or third toes. 

The diagnosis of predislocation syndrome is largely made using clinical judgement, though x-rays are necessary to rule out any underlying pathology, such as fractures or complete dislocations.  An MRI may also be ordered, though it is not always necessary.  The MRI will show the ordering physician whether the plantar plate is torn, attenuated, or if there is any other potential pathology causing the deformity. 

Initial treatment typically involves icing the affected area, rest, and the use of non-steroidal anti-inflammatory medications.  Orthotics may be used to manipulate the position of the foot while walking or running, and various strapping and padding methods may alleviate some of the pain. 

Surgery becomes warranted if there is a failure of conservative therapy.  Typically surgery will address any bony deformities of the foot first, such as hammer digits, metatarsals that are functionally too long, or other problems.  In the case of concomitant hallux limitus, procedures of the first MTP joint may be required to restore normal function to that joint and to take pressure off of the second MTP joint. 

When the plantar plate is ruptured or damaged, that too can be repaired with a direct approach.  This has traditionally been done through an approach through the bottom of the foot, though it has recently been described as being repaired through the top of the foot.  

 Central Florida Foot & Ankle Center, LLC 

101 6th Street N.W. 

Winter Haven, FL 33881 

Phone: 863-299-4551 

www.FLFootandAnkle.com

New Implant Technology Under Investigation

Researchers at the University of Alabama at Birmingham have published an early study on the use of nanodiamonds in joint implants.  The investigators seek to find if the nanodiamonds can improve the metallic interface of the joints, which can often shed debris and cause problems within the body. 

            When metallic debris is created within a joint that has had an implant placed in it, it triggers the body’s immune system.  This can cause a cascade of events, which includes increasing the activity of bone-eating cells near the implant.  When these cells have increased activity, it can cause the implant to loosed, which is a major cause of implant failure. 

            Using a nanodiamond coating, the reaserchers have found, causes less debris to form, which in theory could improve implant success rates.  This is important, because the amount of implants used in America alone is tremendous.  Over 400,000 knee implants and over 325,000 hip implants are placed in Americans every year, not to mention the number of implants used in other parts of the body. 

            Joint implants of the foot and ankle are often used in the first metatarsophalangeal joint, lesser metatarsophalangeal joints, and in the ankle.  Should the nanodiamond technology catch on in the hip and knee implants, it will almost certainly be applied to foot and ankle implants. 

            Much more knowledge of the effect of nanodiamond particles on the body is needed before this technology can be used in humans. While the nanodiamond coating may eliminate the metallic debris that is formed, the constant pressure and grinding forces placed through joint implants can still cause a small amount of the diamond nanoparticle coating to become loose.  The effect of this debris in the body must be known before it can be applied.  Currently, animal models are being used to investigate this. 

            Of course, what is not discussed alongside the research is the cost of such technology.  The cost of using a diamond nanoparticle will almost certainly increase the cost of the implant.  This should be balanced with the increase in success rates seen.  There would need to be a significant increase in implant success rates to begin implementing this technology.  But even if the cost of the implant is increased, if the success rates are in fact much higher, it will most likely decrease the cost of care, lessening the need for secondary and revisionary surgery, and increase the patient satisfaction following surgery.

Central Florida Foot & Ankle Center, LLC 
101 6th Street N.W. 
Winter Haven, FL 33881 
Phone: 863-299-4551 
www.FLFootandAnkle.com