Posterior Tibial Tendon Dysfunction: An Overview
Posterior Tibial Tendon Dysfunction (PTTD) is the most common cause of adult-acquired flatfoot. This condition occurs when the posterior tibial tendon becomes damaged or weakened, which plays a crucial role in stabilizing the foot’s arch and maintaining foot alignment. If untreated, PTTD can progress to deformity, causing significant functional impairment. As a medical professional, recognizing the early signs and staging of this condition is essential in preventing further complications and managing the disease effectively.
Anatomy of the Posterior Tibial Tendon
The posterior tibial tendon originates from the posterior aspect of the tibia, fibula, and the interosseous membrane. It travels along the deep posterior compartment of the leg and passes behind the medial malleolus, where its blood supply is the most limited. This area is particularly prone to tendon rupture due to its poor vascularization. As the tendon nears its insertion on the foot, it splits into several components: the main part inserts on the navicular tuberosity, the plantar portion attaches to the metatarsals and cuneiforms, and the recurrent component connects to the calcaneus. This complex structure is responsible for supporting the medial longitudinal arch and plays a critical role in foot inversion and overall stability during movement.
Pathophysiology of Posterior Tibial Tendon Dysfunction
PTTD primarily develops through tendinosis, a degenerative process caused by repeated microtrauma over time. The posterior tibial tendon, subjected to constant strain, begins to lose its elasticity and strength, eventually being replaced by ineffective fibrotic tissue. In its early stages, patients may not exhibit overt deformity; however, as the condition progresses, the medial longitudinal arch collapses, leading to the characteristic flatfoot appearance. Other deformities such as heel valgus, internal rotation of the tibia, and subtalar joint eversion are common as the tendon continues to weaken.
This condition can be aggravated by risk factors such as obesity, diabetes, hypertension, and prior trauma to the foot or ankle. The aging process also plays a role, with middle-aged women, particularly those over 40 years old, being most susceptible. Certain medications, such as steroids, and underlying conditions like seronegative spondylarthropathies, also contribute to the development of PTTD.
Clinical Presentation and Diagnosis
The progression of PTTD is often slow and insidious, with patients initially reporting medial foot pain, swelling, and weakness. They may describe difficulty standing on their toes or walking on uneven surfaces. As the disease progresses, the foot deformity becomes more apparent, with patients displaying the “too many toes” sign, a hallmark of PTTD where more than two toes are visible when viewed from behind. This sign is indicative of the foot’s inability to return to its normal position due to tendon dysfunction.
Examination typically reveals swelling and tenderness along the posterior tibial tendon, particularly around the medial malleolus. As the disease advances, patients may struggle with a single-leg heel raise, an essential test for diagnosing PTTD. Early stages may allow patients to complete this test, but as the disease progresses, they may be unable to perform the heel raise at all.
X-rays, ultrasound, and MRI are vital tools in diagnosing and staging PTTD. While X-rays may not show early changes, they become useful in advanced stages when deformity and joint degeneration are evident. MRI is particularly beneficial in detecting tendon degeneration and joint involvement, allowing for accurate staging and treatment planning.
Staging and Management of Posterior Tibial Tendon Dysfunction
The treatment of PTTD is highly dependent on the stage of the disease. Johnson and Strom’s classification system provides a framework for understanding the disease’s progression, from Stage I (tendinopathy without deformity) to Stage IV (advanced arthritis involving the ankle joint).
Stage I: Tendinopathy
At this early stage, the tendon remains intact but is inflamed. Conservative treatment is the mainstay of management, involving rest, anti-inflammatory medications, and the use of orthotics or ankle-foot orthoses (AFOs) to support the arch. Physiotherapy aimed at strengthening the posterior tibial tendon and stretching the Achilles tendon is also beneficial. If symptoms persist, a tendon synovectomy may be performed to remove damaged tissue.
Stage II: Ruptured Tendon
At this stage, the tendon has either ruptured or becomes nonfunctional, leading to a fixed flatfoot deformity. Nonoperative treatments may still be tried, but surgical intervention is often required. Surgical procedures typically involve tendon transfers and osteotomies to correct the deformity and restore function. Common procedures include flexor digitorum longus transfer and calcaneal osteotomy.
Stage III: Joint Degeneration
In Stage III, joint degeneration, particularly in the subtalar joint, is present, and the deformity becomes rigid. Surgical options at this stage usually involve arthrodesis (joint fusion) of the subtalar, calcaneocuboid, and talonavicular joints to correct the deformity and alleviate pain.
Stage IV: Advanced Degeneration
Stage IV represents the most advanced stage of PTTD, with involvement of the ankle joint. Surgical intervention is typically extensive, requiring joint fusion and possibly deltoid ligament reconstruction to restore stability and function. In severe cases, pan-talar fusion may be necessary, although outcomes in this stage are often less favorable.
Conclusion
Posterior Tibial Tendon Dysfunction is a progressive condition that can severely affect foot function and quality of life if not diagnosed and treated early. Recognizing the signs and symptoms in the initial stages and initiating appropriate treatment can prevent the need for more invasive surgeries later on. Early referral to an orthopedic surgeon is crucial for optimal management. With advancements in imaging techniques and surgical options, outcomes for patients with PTTD have greatly improved, and early intervention remains key to preserving foot function.
Do you have more questions?
Q. What is the role of the posterior tibial tendon in foot function?
A. The posterior tibial tendon supports the medial longitudinal arch, assists in foot inversion, and contributes to overall foot stability during movement.
Q. How does the posterior tibial tendon become damaged in PTTD?
A. Repeated microtrauma over time leads to tendinosis, causing the tendon to lose elasticity and strength, eventually resulting in fibrotic tissue replacement.
Q. What is the “too many toes” sign in PTTD?
A. The “too many toes” sign refers to the visibility of more than two toes when viewed from behind, indicating foot deformity due to tendon dysfunction.
Q. Which imaging methods are used to diagnose PTTD?
A. Diagnosis involves imaging techniques such as X-rays, MRIs, CT scans, and ultrasounds to assess tendon integrity and foot alignment.
Q. What are common risk factors for developing PTTD?
A. Risk factors include obesity, diabetes, hypertension, previous foot or ankle trauma, aging (especially in women over 40), steroid use, and certain inflammatory conditions.
Q. What are the common symptoms of posterior tibial tendon dysfunction (PTTD)?
A. Symptoms include pain along the inside of the ankle, swelling, a flatfoot appearance, difficulty standing on tiptoe, and an altered gait due to the inability to support the arch properly.
Q. How is posterior tibial tendon dysfunction diagnosed?
A. PTTD is diagnosed through a physical examination, patient history, imaging tests such as X-rays or MRIs, and sometimes an ultrasound to evaluate the tendon’s condition and the foot’s structural alignment.
Q. Can PTTD affect both feet?
A. Yes, although PTTD typically affects one foot, it can sometimes develop in both feet, especially in individuals with underlying risk factors such as obesity or diabetes.
Q. What are the stages of posterior tibial tendon dysfunction?
A. PTTD is classified into four stages: Stage 1 involves tendon inflammation, Stage 2 includes tendon degeneration, Stage 3 features flatfoot deformity with misalignment, and Stage 4 occurs when arthritis develops in the ankle joint due to prolonged dysfunction.
Q. Is surgery always required for posterior tibial tendon dysfunction?
A. No, surgery is not always necessary. Nonoperative treatments like rest, orthotics, physical therapy, and anti-inflammatory medications are effective in the early stages, while surgery may be considered in advanced stages if conservative measures fail.
Q. How do custom orthotics help manage PTTD?
A. Custom orthotics help by providing support to the arch, redistributing weight away from the weakened tendon, and preventing further foot deformity, ultimately improving foot function and alleviating pain.
Q. Can physical therapy help with posterior tibial tendon dysfunction?
A. Yes, physical therapy can help strengthen the posterior tibial tendon and surrounding muscles, improve foot mechanics, and reduce pain through targeted exercises and stretches.
Q. What is the role of corticosteroid injections in treating PTTD?
A. Corticosteroid injections may be used to reduce inflammation and pain in the tendon, providing temporary relief, although they are not a long-term solution and should be used cautiously.
Q. How long does it take to recover from posterior tibial tendon dysfunction?
A. Recovery time varies depending on the stage of PTTD and the treatment method. Nonoperative management may take several months, while surgical recovery can last from 6 months to a year or longer.
Q. Can posterior tibial tendon dysfunction lead to permanent foot deformity?
A. If left untreated, PTTD can lead to permanent foot deformities, including flatfoot, misalignment of the ankle and toes, and progressive arthritis in the ankle joint, which can limit mobility.
Dr. Mo Athar
