When his mother began experiencing pain and signs of flatfoot, Bill Meanwell, CPed, learned that she had posterior tibial tendon dysfunction (PTTD), a condition he often sees in patients. As a pedorthic educator at the International School of Pedorthics in Broken Arrow, Okla., he naturally began looking for the best therapy for her condition.
To properly treat the condition, one first must understand the pathology. Meanwell offers an anatomy lesson: The tibialis posterior muscle attaches to the navicular, where it feeds out like fingers and grabs almost the entire midfoot. The posterior tibial tendon supports the foot’s arch and turns the foot medially.
“Once that is gone, it just has a devastating effect on gait, foot position, everything,” he said.
The role of the posterior tibial tendon is as the primary inverter of the foot, which works against the everters of the foot.
“They should work in harmony,” Meanwell said. “In this case, the harmony is gone.”
He explained the foot’s transformation from an inverted position to a pes planus position.
“Once the foot turns its position, instead of walking over the end of your foot, you are walking over the side of your foot and propelling off the medial edge, not through the tip of the hallux,” Meanwell told O&P Business News. “It dramatically changes the way you walk and function.”
Although PTTD develops over time, the actual rupture will show pathological signs, said Paul A. Chromey, DPM, CPed, pedorthic educator, anatomy instructor in pedorthics at Temple University School of Podiatric Medicine in Philadelphia, and owner/operator of Northeast Pedorthic Services. When the tendon ruptures, the talus bone plantarflexes, adducts and moves anteriorly, collapsing the longitudinal arch.
“This places tremendous tension on the spring ligament,” he said.
The tension then causes the joint to abduct and the calcaneus bone to evert, resulting in a flatfoot.
It is rare, however, to have an actual spontaneous rupture on the tibialis posterior muscle, Chromey said. The most common cause of rupture is chronic or acute stress on a tendon that is already degenerated, attenuated or weakened.
Stages of PTTD
At the time of diagnosis, patients will fall into one of four definitive stages of PTTD. Few patients notice symptoms in stage 1, and so few are diagnosed early. Although there may be some swelling along the course of the tendon, radiographs show no signs of dysfunction.
In stage 2, patients with PTTD start to notice some pain and inflammation along the tendon sheath, a sign of tendonitis. Patients also can detect an increased flattening of the medial arch, which causes the forefoot to abduct on the rear of the foot. This symptom often is referred to as having “too many toes” — a view from behind the patient’s foot shows that the ankle curves inward and more of the toes are visible from the outside. Radiographs reveal decreased arch height, as well as subluxed tail and navicular joints.
|In stage 4 of posterior tibial tendon dysfunction (PTTD), there is a complete valgus collapse of the talus bone, possibly resulting in necrotic ulcerations along that mid-arch collapse.|
|All images reprinted with permission of Paul A. Chromey, DPM, CPed.|
By the time patients enter stage three, they already have experienced considerable deformity and weakness in their feet, accompanied by significant pain, explained Erick Janisse, CO, CPed, vice president of National Pedorthic Services Inc. in St. Louis.
According to Chromey, patients in this classification will have a rigid flatfoot on the hindfoot. Radiographs in this stage show arthritic changes in the tarsal joints.
Stage 4 of PTTD — which is now severe flatfoot — signals the dysfunction’s end stage. Radiographs reveal a complete valgus collapse of the talus bone, Chromey said, possibly resulting in necrotic ulcerations along that mid-arch collapse. Patients experience substantial pain caused by the tendon failure and subsequent destructive changes in the joints.
“By the time they get to stage 4 … there is not a whole lot that pedorthists can do for them,” Janisse said.
Another diagnostic symptom of PTTD is that patients are unable to invert the affected heel, and so pedorthists may ask their patients to perform the heel rise test.
Meanwell uses a single-sided heel raise for classification. Patients in stage 2 or stage 3 of PTTD are unable to balance on one foot and raise their bodies on that foot. At this point, he also finds that patients feel tenderness and the beginnings of structural deformity in that area, as well as possible bony prominences on the medial side as the foot starts to lose its normal or proper shape, he said.
Magnetic resonance imaging is another viable option for diagnosis, and will reveal rupture of the tibialis posterior tendon. Radiographs only reveal a unilateral flatfoot.
Associated with adult acquired flatfoot, PTTD occurs in adults, and usually begins in middle- and upper-middle age. Stage 4 deformity is seen most often in the geriatric population.
Several issues may contribute to weakening the posterior tibial tendon: tenosynovitis, or a chronic inflammation of the tendon sheath; collagen disorders like scleroderma or gout; and repeated corticosteroid injections.
According to Meanwell, the causes of PTTD run the gamut from predisposition through excessive pronation. Also, as with his mother, many of the affected patients are women older than 50 years old.
“It has to do with menopause and osteoporosis changes that women go through in menopause,” he said.
Although typically developing over many years, trauma may jump-start this condition as well. Some patients report feeling the muscle tear after falling from a distance.
“Quite often we see this occur in an automobile accident,” Meanwell said. “Somebody puts on the brake and locks his leg. There is no shock absorbed in the knee, the foot hyper-dorsiflexes and boom, you have this trauma effect to the muscle.”
An attenuation or rupture of the posterior tibial tendon cannot itself lead to the adult acquired flatfoot deformity that a pedorthist sees in older adults with a progressive flatfoot deformity. As the flatfoot deformity progresses, significant ligamentous rupture has occurred, which includes the spring ligament, superficial deltoid ligament, the plantar fascia and both the long and short plantar ligaments.
Our goal in the cadaver lab is to take both flatfoot and normal arch foot specimens and attempt to release their anatomical structures, so as to objectively reproduce a flatfoot. Only then can we evaluate and recognize those various levels of ligamentous rupture and apply them clinically to those stages of an adult acquired flatfoot (AAF) deformity. The pedorthist will then recognize how to support that level of ligamentous rupture for the AAF.
Knowing what level or clinical category of AAF has developed will enhance the conservative approaches available to treat this entity.
For past 2 years, participating pedorthists and I have had the opportunity to attend an advanced pedorthic course sponsored by the Pedorthic Footwear Association and held at the Cadaver Lab Room at Temple University School of Podiatric Medicine in Philadelphia. There we had had access to more than 40 available cadavers. We carefully selected those cadavers that had a somewhat normal arch appearance and other cadavers that had an obvious flatfoot or low arch. The goal was to release or sever via sharp dissection with a #15 scalpel blade several ligamentous structures in an attempt to recreate and witness the occurrence of a flatfoot. After dissecting 16 obvious flatfoot specimens lead me to the conclusion that the posterior tibial tendon was, in fact, the last anatomical structure to attenuate or weaken its longitudinal fibers.
The structures we discovered that preceded the flatfoot were attenuation of the spring ligament fibers, the superficial deltoid fibers, the plantar fascia along with both the long and short plantar ligaments. After dissecting a total of 22 cadavers normal-appearing arches, I noticed that the severing of a combination of the long and short plantar ligaments, the plantar fascia and the superficial bands of the deltoid (medial) ligament resulted in a sagging, lowering, and collapse of the talonavicular joint, thus exposing the head of the talus and navicular bone base.
We had recreated a flatfoot deformity. Furthermore, it is at this level with real patients we now can understand that pronatory forces and weight along the tendon course and insertion of the posterior tibial tendon will cause a posterior tibial tendon dysfunction (PTTD) or actual attenuation of the posterior tibial tendon.
In addition, what compounds this created problem lies in the fact that, after studying and documenting this entity since 2004, we found that it is aggravated by the existence of the shorter limb, i.e., a limb length discrepancy of ½" or greater on the shorter side.
In the pedorthic management and treatment of an older patient who is overpronating, the foot/ankle complex on the shorter leg will develop stages of problems. From an isolated single flatfoot with posterior tibial tendonitis to extreme ankle torsion or medial ankle valgus with bony prominences along the medial malleolus, talonavicular joint and severe attenuation of the posterior tibial tendon that threatens potential for a rupture to occur.
In conclusion, following a 2-year cadaver lab study involving 40 cadaver foot specimens, we found that over many years, walking and other daily activities apply huge forces to the shorter extremity causing overpronation, joint stretching, and tendon and ligament lengthening. This effect will influence the talonavicular joint to lower and eventually collapse, causing a symptomatic single flatfoot. Both in the cadaver lab and with patients, we observe that the “sling-like” tendon insertion of the posterior tibial tendon will support the flatfoot deformity up to the point of rupture.
It is the role of the pedorthist to know the clinical stages and at what stage the patient presents with, in an effort to control any stage of AFF. The hallmark of middle- to late-stage care still is an ankle-foot orthosis in management of AFF and PTTD.
– Paul A. Chromey, DPM, CPed, pedorthic educator and instructor of cadaver lab at Temple University School of Podiatric Medicine in Philadelphia and owner/operator of Northeast Pedorthic Services in Wilkes-Barre, Pa.
Research over the years
Chromey’s research and literary review have demonstrated that PTTD dates back to discussion in the early 1970s, although the four categories were not determined until 1984 by Mueller. Johnson and Strom linked the tendon pathology to both clinical and radiograph findings 5 years later; and, in 1992, Holmes and Mann realized that more than half of patients with an adult acquired flatfoot had diabetes, hypertension or obesity, or some combination of those.
In 2004, Chromey and pedorthic alumni at Temple University School of Podiatric Medicine Cadaver Lab linked PTTD incidence to patients who developed at least a one-half inch shorter leg over the course of their lifetimes. In these cases, the tendons attenuated because of the patients’ overpronation, which resulted in the unilateral flatfoot in the shorter extremity in more than 80% of the patients studied. See “Lower Extremity Cadaver Lab: Let’s Reproduce a Flat Foot” on page 28 fpr more information.
Practitioners also should identify other contributing factors, such as obesity and diabetes, as well as any history of knee replacements or hip fractures that could cause shortening of the leg.
In addition to the symptoms of PTTD, this dysfunction also causes pain in other areas of the body, including the back, hips and knees. Once pedorthic intervention is able to realign the patient, many of the secondary joint issues are improved as well.
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|Once the foot becomes rigid, it is necessary to fit patients with ankle-foot orthoses and custom shoes.|
Practitioners may vary in their treatment methods for tendon dysfunctions. Chromey follows the school of thought that as long as the foot remains flexible, the patient should be treated with a functional orthotic. In the first two stages of PTTD, the traditional orthosis controls the foot in stance phase, which indirectly stabilizes the ankle on the tibia.
Once the foot becomes rigid, however, Chromey believes it is necessary to graduate to an ankle-foot orthosis (AFO). He employs various AFOs to directly control the ankle and the tibia, assisting the foot from stance phase through swing phase.
Meanwell finds that an accommodative orthosis is necessary once a patient reaches the second stage of tendon breakdown. This intervention offers additional support for any bony prominences that have developed on the medial side.
In stage 3, Meanwell recommends that pedorthists fit their patients with a subtalar-control foot orthosis (SCFO), which holds the foot in position and prevents further deformity.
Once patients reach stage 4 rigidity, the only pedorthic option is to fit with custom shoes. At that point, the orthopedic surgeon also can decide to surgically repair the tendon.
Surgery never is the ideal scenario, however.
“To fix the underlying deformity is a big surgery,” Janisse said. “We like to help people avoid surgery whenever we can.
“I think the more aggressive you are, the better your chances of avoiding surgery.”
Chromey impresses on his patients that wearing an AFO may not be a lifetime commitment. With aggressive initial treatment and the proper footwear, he said, pedorthists can decrease pain, improve mobility and even prevent future rupture.
Whether an orthotic or orthosis is prescribed, the treatment is only as good as the footwear that they wear, Chromey insists.
“We emphasize the proper extra-wide, extra-depth orthopedic footwear with a rocker sole,” he said. “It is an essential component of the three-point force system. The shoe provides that final component.”
Pedorthists then can modify the footwear as necessary with heel lifts or lateral wedging.
Working with patients
Janisse compares PTTD to a rope fraying, with no real way to mend it.
“It stretches and elongates and just sort of gets weak,” he said. “There is no orthotic device that can make the tendon whole or strong again. At that stage the orthotic is basically compensating for the loss of strength in the tendon.”
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|Chromey and his team linked PTTD incidence to patients who developed at least a ½" shorter leg during the course of their lifetimes.|
Patients who exhibit flatfoot or hyperpronation — symptoms of the first stages of PTTD — may not be treated for this dysfunction, as these conditions may stand alone. Instead, practitioners may fit with an orthotic.
“Once you get into tendonitis, the abnormalities and bony structures, then it becomes much easier [to diagnose] because it is so blatantly obvious that there is a unilateral issue,” Meanwell said.
He advises practitioners to be prepared for fights with patients — females especially.
“I hate to blame it on one gender, but it does tend to go that way,” Meanwell said. “‘What do you mean I can’t wear high heels?’ That becomes a bit of an argument.”
Meanwell cites Janisse’s father, Dennis Janisse, CPed, and his 2-hour shoe compromise: If his patients wear their orthotics, AFOs and custom shoes on a consistent basis, he permits them to wear a dress shoe for a couple hours during social activities.
To counteract these disagreements, Meanwell stresses the importance of listening to patients.
“Understand their feelings … and work with them as an ally and not as an enemy,” he said.
He instituted this strategy when fitting his mother for custom shoes. He went to Karen Lanier at Branier Orthopedics with photos of his mother’s condition and asked Lanier to help him design shoes — ones that looked as much like his mother’s favorite Keds sneakers as possible.
Practitioners should remember that treating PTTD is as easy as looking for the patients’ symptoms, Chromey said.
“We need to listen to our patients, look at the abnormal [wear patterns] on the soles of their shoes, and we need to start measuring legs to see just how much shorter they are,” he said. “There are tremendous benefits to balancing everybody.”
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Stephanie Z. Pavlou is a staff writer for O&P Business News.