Posterior Tibial Tendon Dysfunction (PTTD)
Posterior Tibial Tendon Dysfunction (PTTD)
The tibialis posterior muscle (TPM) is the deepest muscle of the deep posterior area of the lower limb. Long muscles arise from the posterior interosseous membrane, the superior two-thirds of the fibula's posterior and medial surface, and the proximal tibia's superior aspect (Nicholas M. Corcoran; Matthew Varacall,2023). Located deep on the lower leg, between the flexor digitorum longus and flexor hallucis longus, this muscle provides stability for the medial arch of the foot. This arch is important for walking and running because it helps improve foot flexibility, shock absorption and propulsion. The springy ligament connects the calcaneus to the navicular which is a very important ligament for supporting the arch of the foot (Carson James Smith, MD, Taylor Beahrs, MD, Brian M. Weatherford, MD, 2023). The muscle plantar flexes and inverts the foot providing significant medial arch stability, the fibularis longus tendon, along with the tibialis posterior tendon maintains the curvature of the arch under the base. Furthermore, the fibularis longus tendon and transverse head of the adductor longus aid in stabilising this arch (Sam Little, 2022). As a result of their shape, they support the weight of the body while also absorbing the shock produced during movement. The flexibility conferred on the foot by arches facilitates functions in walking and running. A normal medial arch allows the foot to be flexible and adapt to different terrain conditions when the foot is flat on the floor and then stretches and becomes rigid at the toe-off when the foot pushes forward during walking or running. It changes continuously during the gait cycle to keep the foot moving forward as efficiently as possible. The special function of the posterior tibialis tendon is to raise the arch right where the toe comes off, which then locks the foot into a rigid bar ready to push forward. (this is very limited and unconvincing account of the foot)
Posterior tibial tendon dysfunction (PTTD) is the most common cause of flatfoot deformities in adults, most commonly in women over 40 and older, because the tendon often degenerates or breaks with age. But it can also affect obese people by adding weight to the feet and putting extra stress on the tendon, systemic diseases such as high blood pressure, diabetes and rheumatoid arthritis that weaken the tendons, previous foot or ankle tissue damage, joint diseases, previous surgery, steroid use, repeated high impact on the feet, footwear such as sandals or heels cause more stress on the tendons (NHS, 2023). (very limited coverage and understanding) In PTTD the tibialis posterior becomes weak and painful. Tendon dysfunction affects the neighbouring ligamentous structures which eventually leads to bony involvement and deformity. The posterior tibial tendon is commonly involved in an overused injury caused by excessed pronation, injury from exercise, or overwork on the foot which can cause the tendon to become strained, inflamed, overstretched or torn resulting in pain and leading to flatfoot (Ross MH, Smith MD, Mellor R, Vicenzino B., 2018). The failure of the tendon will affect adjacent ligaments and ultimately result in bony involvement and deformity, structural changes affecting the midtarsal, subtalar and finally the ankle joint. During the loss of function of the tendon, the medial longitudinal arch collapses, causing the tibia and talus to rotate relative internally, the subtalar joint to evert, pushing the heel into valgus alignment, and the talonavicular seal to abduct (Myerson M, Solomon G, Shereff M., 1989). With the heel aligned, the Achilles tendon moves laterally, which leads to a contracture of the tendon, which eventually leads to lateral hindfoot pain as the deformity worsens (Deland JT., 2008). Initially, the symptoms are pain and swelling on the inside of the ankle, and the pain is made worse by walking or running. In the later stages, the tendon can weaken and degenerate to the point where it can no longer lift the arch properly during the gait cycle. Later, this causes the medial arch to collapse, which can be seen as flatfoot. Symptoms patients complain of include (NHS, 2023): discomfort and swelling on the outside of the ankle as well as on the inside of the ankle ranging from mild to severe, pain and swelling may increase with lengthened walking and activity, weakness in the legs and ankles, as if the strength would disappear when you lift your heels off the ground while walking, inability to rise on toes, you may notice that your ankles roll inward and your feet become flatter, pain on the outside of the ankle as the foot flattens and changes position as a result of tendinitis, and you may experience tingling, shooting, burning, or stinging. The symptoms of posterior tibial tendon dysfunction gradually worsen and as such are characterised by four stages of progression (Matt Raden, 2022): (overall this is very superficial, showing lack of foot pathomechanics)
1st stage: is often missed because there are few or no symptoms, medical imaging shows nothing abnormal. However, you may have mild inflammation of the tissue surrounding the tendon and mild pain, which may be your first symptom. You can still pass one heel test without any discomfort.
2nd stage: a tear in the tendon affects its regular function, and your foot may become noticeably flat. Radiological examination shows the beginning of arch collapse deformation, during your physical exam you can no longer do the single-leg heel test.
3rd stage: it is characterised by significant degeneration and deformity of the ankle joint, which is rigid, meaning it cannot be corrected manually. Physical examination at this point shows severe sinus pain, while radiological examination shows subtalar arthritis and arch collapse deformity. You must complete more than one heel test.
4th stage: the deltoid ligament is damaged and there are degenerative changes in the ankle joint. The deformity of flatfoot is worse and stiffness throughout the entire area of the foot. Physical examination shows ankle pain and severe sinus pain. As for the x-ray, it shows arch collapse deformity, subtalar arthritis and talar tilt. (where is the information being cited from)
Podiatrists carry out tests to check the position of the foot and the strength of the tendon in the foot, e.g. (Modarresi S, Motamedi D, Jude CM., 2021): (lay terminology)
Swelling and pain: swelling and pain are usually found just behind and below the inside ankle along the posterior tibial tendon, the arch itself may also be painful.
Checking foot posture: fallen arch, STJ axis is more medially translated and internally rotated.
Too many toes in sight: you should only be able to see the 5th toe and maybe the 4th from directly behind the foot position when standing, if you can see more than 2 toes in a patient then this indicates a flattened foot.
Analysing gait: you may notice increased forefoot dorsiflexion and abduction and increased plantar flexion and hindfoot inversion in patients with PTTD in a walking position.
Single leg heel raise test: if a patient can raise the heel of good without struggling but struggles with the affected foot due to pain or weakness then this might indicate a weakness of the tendon.
Range of motion: a foot where there is no motion or motion is limited.
Ultrasound: it can be used to analyse the size of your tendon, detect degeneration of the tendon, or detect fluid in the tissue surrounding the tendon, which can occur in the early stages of PTTD.
X-ray: the front, back, and sides of both legs have detailed depictions of the bones. It can help detect arthritis or a fallen arch. They also help detect joint degeneration in the later stages of PTTD.
MRI: can determine the health of your tendons and surrounding muscles. MRI can be used to arrange non-surgical treatment early on, and in later stages, MRI can be used to arrange surgical treatment.
CT scan: creates a 3D image of soft tissues and bones, it can provide more detailed images than X-rays. A CT scan can help identify arthritis or confirm PTTD.
(the structure of this assignment has now turned into a note form, this work does not reflect the amount of time given for its completion)
Treating the condition as soon as possible is important as it is a chronic progressive disease, hence it is easier to treat it early to avoid the need for surgery. Treatments available include (NHS, 2023): (limited effort in terms of literature review and referencing)
Symptoms improve in most patients with appropriate nonsurgical treatment, e.g.:
The first step is to reduce or even stop activities that make the pain worse,
switching to low-impact exercise is beneficial. Cycling, elliptical machines or swimming do not affect the leg much, and most patients can perform these activities without problems. Apply an ice pack for 10 minutes, 4 times a day can reduce pain and inflammation. Losing weight is also a very effective way to relieve stress on the arch and its supporting structures. Taking nonsteroidal anti-inflammatory drugs such as ibuprofen or naproxen, reduces pain and inflammation.
To keep pressure away from the injured joint, wear comfortable shoes, sneakers, or hiking boots with a high, firm heel that offers the most support. Avoid sandals or backless shoes because they tend to have a soft, low heel that increases stress on the ankle and tendons. A specially made orthosis is a shoe insert designed to support the foot and position it for more comfortable walking, it is a common non-surgical treatment for flatfoot. (this has not been written to either level 4 or 5 standard)
Tendon-strengthening physical therapy can help patients with mild posterior tibial tendinitis. The calf and Achilles tendon stretching to improve ankle stiffness is also an important part of any flat feet treatment program, long seating with armrests and the legs resting against the wall. Press your toes into the wall as if you were trying to push the wall away, and feel your calf muscles tighten. Repeat 15 times and do 3 repetitions with 2 minutes of rest after each set, once a day for 12 weeks or until instructed to stop. Patients can also try double-heel raise exercises, for example: standing against a wall or support surface, such as the back of a chair. Make sure your feet are hip-width apart and your toes are forward, press your feet onto the balls, lifting your heels off the ground for 3 seconds. Lower yourself slowly to the ground for 3 seconds. Repeat 40 times and do repetition twice with a 2-minute rest after each set. Do morning and afternoon for 12 weeks or until advised to stop. The clinician may ask you to do this exercise on only one leg at a time after your appointment.
A simple over-the-counter ankle brace can help with mild to moderate flatfoot. The brace supports the joints of the ankle and the back of the foot and thus takes the stress off the tendon. Heavy, stiff or arthritic flat feet may require heavier braces (Arizona Brace, Richie Brace). These braces can be customised and sometimes help patients with advanced deformities avoid surgery.
Surgical options may be offered if the nonsurgical methods fail to treat PTTD, the type of surgery depends on how acute the condition is, e.g.:
Tendon transfers can be done in a flexible flat foot to restore function to the injured posterior tibial tendon. The most commonly used tendon for this transfer procedure is the flexor digitorum longus (FDL). In this procedure: The diseased tendon is removed and replaced by a tendon from the other leg or if the disease in the posterior tibial tendon is not too significant, the transplanted tendon is attached to the preserved and not removed PTT.
With an osteotomy, a flexible flatfoot can be reshaped to create a more normal arch shape, correcting the shape of the foot is important to relieve stress on the PTT. A very common flat foot osteotomy involves cutting the heel bone (calcaneum) and moving it outward back under the middle of the ankle. Another type of calcaneus osteotomy involves lengthening the outside of the heel to push the toes back into the middle which corrects the too many toe deformities. Other foot or toe osteotomies may also be necessary to restore the shape of the arch itself.
Depending on the patient, recovery is prolonged and requires a break of at least 3 months. The more serious the problem, the longer it takes to recover.
Even though PTTD is the most commonly acquired flatfoot deformity many diagnoses can have similar symptoms to PTTD, such as (Pomeroy GC, Pike RH, Beals TC, Manoli A., 1999):
Charcot arthropathy, the tarsal coalition, neuromuscular disease, traumatic disruption of midfoot ligaments, and inflammatory arthritis.
