Posterior Tibial Tendonitis

Introduction

Posterior tibial tendonitis (PTT), also known as posterior tibial tendon dysfunction (PTTD) is the most widespread cause of acquired flatfoot disease in adults. The disease causes degeneration of the tendon, associated with significant foot pain and weakness. Without timely diagnosis and treatment, the condition can progress to more advanced stages, sometimes resulting in foot deformity and the onset of degenerative changes in nearby joints. The disease can be detected using clinical imaging tools, such as X-ray scans, ultrasound and magnetic resonance imaging. Identification of PTT at its early phases means it can be treated in a timely manner to prevent disease progression.^1,2 

What is Posterior tibial tendonitis? 

Posterior tibial tendonitis (PTT) is a condition that affects the foot and the ankle and is among the most common and well-recognised bone abnormalities. Elderly people and those assigned to female-at-birth (AFAB) are particularly at risk of developing the condition.³   

PTT typically begins with the onset of several indicative signs in the early stages. The tibialis posterior tendon is located on the deep level around the back and inside of the lower leg, foot, and ankle, thus it is among the most stabilizing structures of the foot. When the tendon is affected (for instance due to a strain or physical trauma), it becomes inflamed. When inflammation persists over a long time it causes the arch along the inside of the foot to flatten.⁴  

This foot-flattening is known as Posterior Tibial Tendon Dysfunction (PTTD). Currently, a high proportion of patients come to specialists at advanced stages of PTTD, when the severity of the symptoms is significant. Diagnosis of this condition is fairly straightforward and can be achieved without any special investigations, for example, from a physical examination. Additionally, symptoms of the disease can be relieved and progression halted in many patients from relatively simple treatment.^1,2 

Anatomy of the ankle

Tibialis posterior muscle (TPM), is one of the deepest muscles that is located at the back of the lower leg. The tibialis posterior tendon is bound to the tissues of the sole of the foot via many attachment points.⁵

The tibialis posterior (TP) is a secondary flexor of the foot connected to the calf muscles and the Achilles tendon. TP supports the arch of the foot and inverts the midfoot (which is what gives the foot its typical arched shape). In a healthy person, the medial arch (the inside arch) of the foot is higher than the lateral arch (the outside arch) and is maintained by several bones.¹

Stages of posterior tibial tendonitis 

There are four stages of PTT:

• Stage I -  the tendon is inflamed but intact and without clinical deformity¹
• Stage II - the tendon is  ruptured and otherwise dysfunctional, which causes planovalgus deformity (bowing of the ankle bones into a slant)⁴ 
• Stage III - indicated by advanced foot deformity which cannot be simply corrected and osteoarthritis  seen in the hindfoot joints⁴
• Stage IV -  characterised by degeneration and arthritis of the ankle joint (typically at this advanced phase, one or more joints become affected)

Causes/risk factors

While the cause of this condition remains uncertain, there are numerous factors that have been found to initiate posterior tendon tendonitis or speed up its progression. 

According to NHS statistics, mechanical trauma has been identified as the root cause in approximately 50% of diagnosed cases of PTT. Patients report pain and swollen feet and ankles, which are worsened by physical activity. The tendon can also be affected by repeated microtrauma (small, sustained injuries to the foot) or restricted blood supply to the posterior tendon. Those with mild flatfootedness in early life may also develop the disease at an older age due to the additional mechanical demand on flat feet put on posterior tendons throughout life. 

Anyone can become affected by this condition but it is more common in: 

• Middle-aged and elderly people assigned-female-at-birth (AFAB)
• Those who have had repeated episodes of mechanical trauma 
• People with a history of ankle injuries, spares or tears of the tendon 
• Those with mild flatfootedness 
• People who excessively use the tendon, for example, by standing for long hours or using altered foot mechanics
• Obesity 
• Ageing 
• Chronic conditions that can affect and weaken tendons
• People who wear inappropriate footwear (i.e, shoes that don't support the ankle or sole of your foot)⁵

Symptoms

Symptoms of PTT include:^2,5

• Stiffness, weakness lack of flexibility of the ankle
• Pain and swelling (ranging from mild to severe)
• Symptoms that worsen at the end of the day, particularly after walking long distances
• Inability to raise up onto your tiptoes
• Ankles that fall inward and feet that become flatter and abnormally positioned
• The ability to walk and stand balanced worsens gradually

Diagnosis

Medical history

The healthcare provider will ask for your medical history including the symptoms you are experiencing, history of ankle injuries, spares or tears of the tendon, mechanical trauma etc, to determine the potential cause of PTT.

Physical examination

During the physical examination, your healthcare provider with check for certain signs that help identify PTT and its stage. In stage I/II, the signs of inflammation such as pain, swelling and tenderness along the course of the tendon and inversion of the foot will be evident. You may also experience difficulty rising on your toes, or weakness after several heel rises.

In the later stages, there are fewer inflammatory markers but pronounced flatfoot deformity, with some asymmetry seen on the back of the feet. This leads to the “too many toes sign”, where more toes than normally can appear on the lateral border of the foot.  Another sign includes a positive functional test for the inability to perform a single heel rise (healthy individuals can perform a single heel rise up to 10 times).⁴

Imaging 

Doctors can use radiography imaging on the foot and ankle to rule out other conditions that cause flatfoot deformity, make a certain diagnosis and assess the stage of the disease. However, there is often no need for magnetic resonance imaging (MRI) or ultrasonography (ultrasounds), as the diagnosis can be made through identifying clinical features from physical and visual assessment of the foot.

Treatments

Non surgical treatments

Conservative non-invasive treatment includes non-steroidal anti-inflammatory drugs (NSAIDs), decreased physical activity and immobilization of the tendon to suppress the onset of acute inflammation. The use of orthoses (bone support devices) can also help to control persistent symptoms.² 

• Stages I and II: the flexible foot

Conservative measures such as immobilization of the ankle with a plaster cast for a short period (4-8 weeks) can help to resolve inflammation. Wearing specific footwear such as ankle boots is highly advised as it will allow you to hold the heel in a neutral position.

• Stage III and IV: the rigid flatfoot

At these later stages, there is less inflammation of the tendon but patients will have a rigid acquired flatfoot. Treatment options include accommodating the foot deformity with custom-made rigid orthoses/appropriate footwear.

Surgical treatments

• Stage I — if non-invasive treatment fails to resolve symptoms of posterior tendon tendinitis, patients are advised to undertake surgery to modify the underlying foot deformity, called a corrective osteotomy. This usually helps to halt disease progression and restore/maintain adequate foot function. This can be also useful together with tendon debridement or tendon transfer⁵
• Stage II — surgical options are a combination of tendon transfer and osteotomy. This will essentially allow to bring necessary corrections into the bone structure of the affected foot and optimize the mechanical output of the posterior tendon⁵ 
• Stage III — at this stage, you should take care of the foot deformity and immobilise the involved joints (called arthrodesis), which will subside the pain and allow bones to come together and grow appropriately⁵
• Stage IV — at this stage degeneration of the tendon and body joints is observed, which can be treated by arthrodesis on several of the foot and ankle joints⁵

FAQ

How long does it take for posterior tibial tendonitis to heal?

Healing PTT takes approximately 6-12 weeks on average, if it is detected in the early stages and handled appropriately by conservative treatment along with non-impact exercises, and supportive footwear. In chronic cases, appropriate physiotherapy might be required to achieve the best results, and strengthen the tendon and might require up to three months from the beginning of the treatment.

Can I still walk with posterior tibial tendonitis?

As simple as walking can be, it is important that the inflamed tendon is completely immobilised at the early stages of the disease. Physical activity can have a negative impact on the healing process. After surpassing the stage of acute inflammation, short, frequent walks are encouraged. A walk lasting 15-30 minutes a couple of times a day is better for the recovery process as compared to a single longer walk. The time or amount of exercise should be modified in association with your overall well-being and symptoms. Consistent exercise during the healing process can help to avoid irritation of the tendon and painful sensations.

When should I contact my doctor?

Upon detection of common signs and symptoms of Posterior Tibial Tendonitis, it is highly advised to see a physiotherapist and perform a simple examination for a clinical diagnosis. 

Summary

Dysfunction of the tibialis posterior is a common condition and the most widespread cause of acquired flatfoot deformity. The elderly are highly prone to developing this condition, with those assigned-female-at-birth (AFAB) and older than 40 most at risk. The disease can be classified into 4 stages and often presents at its later stage, while early-stage PTT is associated with pain and swelling of the medial hindfoot. Patients may also notice progressive flattening of the foot and experience partial or substantial loss of tendon flexibility. Treatment options are versatile and wide-ranging, varying from non-invasive treatment (including non-steroidal anti-inflammatory drugs and tendon immobilization) or more serious surgical interventions.