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The Design of the Ankle

The overall ankle joint behaves like a mortise joint or sophisticated hinged joint. It has up to 15 degrees of upward motion (dorsiflexion), and up to 30 degrees of downward motion or plantar flexion. This is possible because the ankle joint is a complicated mechanism, composed of three joints working together:

  • the tibiotalar joint (or main ankle joint, made up of three bones: the tibia, the smaller fibula, and the curved talus)
  • the tibiofibular joint
  • the talofibular joint.

There are also three lateral ankle ligaments - the anterior talofibular ligament, the calcaneofibular ligament, and the posterior talofibular ligament. On the medial side (great toe side) the deltoid ligament is composed of the superficial and deep component, and connects the tibia and talus.

About Acute Ankle Sprains & Injuries

Acute ankle sprains are one of the most common orthopaedic injuries, with an estimated 27,000 occurring in the United States each day. Ankle sprains, however, are much like Rodney Dangerfield because they “get no respect". Most ankle sprains are treated conservatively, with limited or no treatment. Fortunately, most do well with this benign neglect. However, studies and my personal experience note that up to 15% of patients require in-depth care for serious continuing symptoms or complications after an ankle sprain. 

I, Dr. Bowman, once conducted a multi-Center ankle sprain study for the American Orthopedic Foot & Ankle Society to study ankle sprains and conservative treatment. Our findings showed that with appropriate early treatment of ankle sprains, we were able to reduce the incidence of severe complications to 4%.

The most common type of ankle sprain is a lateral ankle sprain, involving injury to the lateral ankle ligaments. 

  • 75% involved the ATF ligament, with 40% involving the CF ligament and 9% involving the ATF. 
  • The usual mechanism for producing a lateral ankle sprain is an entry to the foot down in plantar flexion and twisting in (inversion).
  • The patient may notice a “ pop" and experience immediate discomfort. 
  • There is usually swelling around the fibula on the lateral side of the ankle as well as bruising or ecchymosis. 
  • In some cases the lateral ankle ligaments may detach with a small piece of bone, producing an avulsion fracture of the fibula.

A medial ankle sprain, involving the deltoid ligament, occurs in approximately 4 to 7% of ankle sprains. A common cause of this injury is turning the ankle out with the foot dorsiflexed (upwards). The patient will usually notice swelling medially with bruising. 

Occasionally a lateral ankle injury will result in tearing of the inner osseous ligament between the tibia and fibula, causing a so-called “high sprain". This is a more severe version of the common lateral ankle sprain, resulting in a higher incidence of instability and chronic problems. It must be treated more aggressively and can take between 6 to 12 weeks to heal.

Diagnosis & Treatment (Rehabilitation) of Acute Sprains

Initial evaluation of ankle sprains involves obtaining the history surrounding the injury and then carrying out a careful physical examination. We examine and evaluate a patient’s range of motion, tenderness over the bones or ligaments, and signs of instability.

Examples of testing include the following:

  • The anterior drawer test involves pulling the talus forward in the ankle joint and checking the stability of the ATF ligament. 
  • The talar tilt test involves pulling the talus into varus toward the big toe, and checks the CF ligament. 
  • The eversion test checks for the stability of the interosseous ligament, and involves twisting the talus laterally towards the fibula and spreading the tibia and fibula. 
  • X-rays are also usually taken to rule out any fractures.

Initial treatment of acute ankle sprains involves protection with a protective boot or Aircast stirrup to avoid future injury. Weight-bearing may be allowed as tolerated by the patient, although every case is different and may have various limitations as a result.

Therapy, if needed, will be started immediately to avoid swelling and to regain range of motion. Once the swelling is diminished and the range of motion is regained, strengthening exercises are initiated to enhance the muscles around the ankle joint, which act as stabilizers and provide joint support. 

Balance and proprioception exercises may also be prescribed. Once the swelling is diminished, range of motion is good, and stability is regained, continued strengthening in sport-specific exercises can be initiated.

About Sprains Involving Fractures: 

Ankle sprains involving small avulsion fractures that are nondisplaced may be treated with a protective boot; patients will be told to not bear their weight for 2 to 3 weeks, followed by the above treatment plan. 

For ankle sprains involving significant fractures, the fracture may need to be repaired with internal fixation. This surgery is performed on an outpatient basis with general or spinal anesthesia. A small incision is made over the fracture, and the fracture and ligaments are repaired directly. A protective boot is prescribed, and patients will be told to not bear their weight for 4 to 6 weeks, followed by the above ankle rehabilitation program.

One frequently missed type of injury is a small avulsion fracture from the front or anterior lateral part of the calcaneus. Left untreated, the fracture will frequently not heal, resulting in a painful nonunion. Treatment consists of removing the small fracture fragment. This procedure is performed on an outpatient basis with general or spinal anesthesia. There is limited weight-bearing allowed for two to 4 weeks after surgery, followed by therapy. Surgical risks include anesthesia-related risks, wound healing problems, or infection.

About & Addressing Chronic Sprains

A chronic ankle sprain is an ankle sprain that has continuing symptoms such as persistent instability with giving way episodes, chronic swelling, or pain or stiffness. The most common complications after an ankle sprain are stiffness, scarring, and poor healing of the injured ankle ligaments. (Scarring is problematic because scar tissue is not as elastic as normal ligamentous tissue. )

Treatment for chronic ankle issues consists of therapy to regain motion, followed by strengthening exercises. In severe cases, arthroscopy and debridement or trimming of the scar tissue in the ankle capsule may be required. This is an outpatient procedure with general or spinal anesthesia. There will be a protective boot and patients will be told to not bear their weight for a period of time dependent on their health needs afterward. Therapy will also begin immediately to begin restoring any lost range of motion. 

About & Addressing Undiagnosed Ankle Injuries

In some cases, an “ankle sprain that does not get better" may actually be caused by an undiagnosed injury. An example of this type of health problem includes an osteochondral lesion of the talus (OLT), which is a small fracture of the cartilage and bone of the talus produced when it twists inside the ankle during the sprain injury. This issue is frequently not diagnosed until months after the initial injury, and any initial x-rays taken may not show a conclusive result. As a result, an MRI may be required to detect this health issue. Treatment involves arthroscopy and debridement or removal of the small fragment. This is also an outpatient procedure with general or spinal anesthesia. A protective boot is prescribed and patients are ordered to obey non-weight bearing guidelines for 6 weeks after their surgery. Risks with surgery and treatment include anesthesia-related risks, wound healing problems, infection, or ankle arthritis.

About Mild Instability of the Ankle

Patients with mild instability of the ankle after an ankle sprain may notice chronic swelling and discomfort in the anterior (front) and lateral portion of the ankle, secondary to irritation from the talus sliding slightly out of place with activities.

Symptoms of severe ankle instability will include the ankle repeatedly giving out, as well as swelling and discomfort. 

Initial treatment includes appropriate ankle rehabilitation and strengthening as described above. Orthotics with a lateral heel wedge may also be used. If conservative treatment does not work, arthroscopy and lateral ligament stabilization may be required. 

About Arthroscopy and Lateral Ligament Stabilization Treatment

We pioneered this innovative, minimally invasive technique approximately 10 years ago. This procedure is performed on an outpatient basis, under general or spinal anesthesia. 

Two small incisions, or portals, are made in the front of the ankle. An arthroscope is inserted to visualize the joint. A small shaver is used to debride or clean up the joint. And a thermal probe is then inserted to heat and shrink collateral ligaments. 

After surgery a protective boot and dressing are applied. There is no weight-bearing allowed for 6 weeks while the ligament is healing, similar to the older open techniques. At 6 weeks, patients will begin an appropriate ankle rehabilitation program and progressive weight-bearing restoration.

Risks with this procedure are related to the use of anesthesia, as well as the potential for wound healing problems and/or infection.