Archive for September, 2010

Treatment of Sinus Tarsi Syndrome

September 18, 2010

Where and what is the sinus tarsi:

The word “sinus” refers to a cavity, most often in bone. The cavity known as the sinus tarsi is located on the outside of the foot in front of and below the outside anklebone. The cavity is formed at the junction between the heel bone and the bone that sits over the heel bone called the Talus.  The heel bone forms the floor of the cavity and the talus creates the roof.

Within the cavity there are blood vessels, nerves and ligaments.  The ligaments function to hold the two bones together.

Symptoms:

“Sinus Tarsi Syndrome” refers to a painful condition located in this cavity in the rear portion of the foot. The pain is made worse with weight bearing. The pain can become much more intense when walking, running or hiking on uneven surfaces.

Causes of Sinus Tarsi Syndrome:

The most common cause of sinus tarsi syndrome is an inversion injury to the foot. This occurs when the foot rolls inward and stretches the soft tissue in the cavity.  When the foot is stressed by this inward motion a tear or strain occurs to the ligaments. The injury to these ligaments results in inflammation, swelling and thickening.

The other causes of this condition are structural as apposed to the injury noted above. One of these structural abnormalities that can occur is growths or masses of soft tissue.  Over growth of nerve or fat tissues in the cavity can cause increased pressure and result in pain. The pain in this area can also be caused by deviations in the bone structure. For example, bone spurs; arthritis and bone bridges can be responsible for the development of sinus tarsi syndrome.

Another helpful procedure to determine the exact location of the pain is to inject the sinus tarsi with a small amount of local anesthesia. If upon examination after the injection the pain is gone the diagnosis is confirmed. If however, the pain is still present following the injection the injury may be in another location in the foot.

Non-Surgical Treatment:

Research has shown that a majority of the people with sinus tarsi syndrome will respond favorably to conservative management. Rest, ice and compression are suggested to reduce the inflammation. Oral anti-inflammatory medications can be prescribed to further decrease the pain and swelling.

Another treatment option is to tape the foot to attempt to limit the motion at the subtalar joint. If the taping successfully reduces the pain long term treatment with a custom orthotic can be used to control the motion of the rear foot. In most cases foot orthotics are sufficient to treat this condition, however in some cases an ankle foot orthotic may be necessary to fully control the motion.

Finally, a steroid injection into the sinus tarsi may be effective at relieving the pain.

Surgery:

In conservative measures have not helped to relieve the pain surgery may be needed.  A common surgical procedure to threat this condition is decompression or removing the abnormal tissues from the cavity. If the MRI scans shows a soft tissue mass present in the sinus tarsi surgical removal of the mass will be needed.

After the surgery, protected weight bearing in a post-operative shoe or walking boot will be required for a period of approximately 2-4 weeks.

If this surgery fails or the patient has severe arthritis the bone in the rear foot may need to be fused.

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Tailor’s Bunionette and its Treatment

September 5, 2010

Most people know that a classic “bunion” appears as a bump on the side of big toe joint. A Bunionette or tailor’s bunion is like the big toe bunion, but in this case there is a bony prominence on the outside of the foot at the base of the small toe. The term ‘tailor’s bunionette originated from tailors in Asia who sat on the ground with their legs crossed resulting in increased pressure on the outside of their feet. This increased pressure caused thick skin formation on the outer aspect of the foot.

Anatomy of a Tailor’s Bunionette:

The fifth or little toe sits at the end of a long bone called the fifth metatarsal.  At the junction of these bones is the joint where the bunionette forms.

Causes of Tailor’s Bunionette:

There are many factors that cause a tailor’s bunion. Structural causes of tailor’s bunion can be an enlarged fifth metatarsal head. Increased angles between the fourth and fifth metatarsals can also cause this deformity. Finally, bowing of the fifth metatarsal may also lead to a Tailor’s bunion.  Or some combination of the above may contribute to the cause.

Symptoms:

Tailor’s bunions may or may be painful deformities. If pain is present, it usually occurs with shoes. The area becomes painful when the bony prominence of fifth metatarsal head rubs against the shoe, resulting in pain and inflammation. Continued shoe friction against the tailor’s bunion can cause swelling, redness and callus formation. On examination, there is pain when pressure is applied to the outside or bottom of the fifth metatarsal head. A fluid-filled pouch, called a bursa, may be found between the bone bump and the skin. This forms as a process of the body’s protective mechanism to protect the bone against the friction from the shoe.

Diagnosing:

The diagnosis of a tailor’s bunion is based on physical exam and imaging. X-ray imaging is performed to evaluate the increase angle between the fourth and fifth metatarsals. This diagnostic tool is also used to determine how much of the bump is composed of bone and how much is do to the swelling from the above mentioned bursa sac.

Conservative Treatment:

Non-surgical treatment is used to decrease the pain and inflammation from a tailor’s bunion. This includes anti-inflammatory medicines, steroid injections. Pads and shoe modification such as a wider toe box or softer materials are used to decrease pressure on the area.

Surgical Treatment:

Surgery is indicated when conservative treatment fails to eliminate the pain. There are several surgical techniques used for the treatment of this deformity. The type of surgery performed will depend on a patient’s medical condition, findings on physical exam and the structure of the fifth metatarsal as determined by X-ray imaging. Surgery for a tailor’s bunion can be performed on the metatarsal head (the end toward the toe), shaft (the middle of the bone), or metatarsal base.

If the problem is found to be an enlarged metatarsal head then this area can simply be shaved down. If there is an increased angle between the fourth and fifth metatarsal bones this angular relationship may need to be changed. Therefore, this condition may need further modification by making a cut across the metatarsal and shifting the end of the bone. After shifting the cut section of the metatarsal, a screw may be used to maintain the position. If there are significant angular abnormalities between the fourth and the fifth metatarsals, then a surgical procedure at the base of the bone with screw fixation may be required.

Expectations After Surgery:

When the procedure is performed on the metatarsal head or shaft, immediate weight bearing in a post-op shoe is allowed. However, procedures performed on the metatarsal base are more disabling and need to be non-weight bearing with crutches. After surgery when returning to the doctors office for post operative care, follow-up X-rays to evaluate bone healing will determine when walking may begin. Additionally, as with all surgeries there will be swelling, pain and tenderness after the procedure. Medicines to control the post-operative pain and swelling will be available to the patient. Some of the inherent risk associated with this surgery are that the deformity may return or that there may be an under correction of the deformity.