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Diagnosis & Treatment of Ankle Disorders
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Diagnosis & Treatment of Ankle Disorders

The ankle is a complex joint consisting of the tibia, talus, and fibula bones. The most common bone in the ankle to have cartilage injury is the talus. The cartilage of the talus is like any other articular cartilage and is arranged similarly to that in other weight-bearing joints. It is thought that the ankle joint is less likely to develop degenerative osteoarthritis than the hip due to its ability to resist tension (tensile forces) over time.

Injury to the ankle and stretching (instability) of the ligaments can lead to cartilage injury to the ankle joint.

Intended audience

This article is intended for anyone suffering from damage to their articular cartilage and their families who would like to find out about cartilage disorders of the knee, as well as anyone interested in cartilage problems.

What are cartilage disorders of the ankle?

The most common ankle injuries are sprains, with a daily occurrence (incidence) of one in every 10,000 people. In the U.S., for example, there are 23,000 ankle injuries every day, with the highest injury rate for every hour of play in basketball, soccer, and volleyball. The articular cartilage is damaged by direct impact on the bone due to ankle sprains.

Fractures are becoming recognised as a major cause of cartilage damage and, in this context, are called bone and cartilage (‘osteochondral’) defects (lesions) of the talus. Both acute (new) injuries and chronic (long-term) insufficient ligament stability can lead to osteochondral lesions of the talus [Figure].

Cartilage injury becomes more likely as the energy and severity of an ankle injury increases.

Patients usually have persistent pain after an ankle sprain or injury. Pain is typically deep inside the ankle joint and may be accompanied by occasional swelling, stiffness and weakness. Mechanical symptoms such as locking and catching may also be present.

It may be a long while after the injury before they present to a doctor, with patients taking up to three years, in some cases. High-level athletes often tolerate the pain and may present after numerous injuries.

How are cartilage disorders of the ankle diagnosed?

Some surgeons find that injection of a local anaesthetic into the ankle joint can help determine if the pain is being caused by a cartilage defect (lesion) or other factors. Other causes of pain that should be considered include:

  • Mechanical ligament instability;
  • Deep bone bruises;
  • Loose cartilage bodies (floating bone chips);
  • Other ankle bone fractures;
  • Tendon injury;
  • Nerve pain from a stretch injury; and
  • Impingement of the ankle from chronic scar tissue inside the ankle.

X-rays of the ankle are appropriate in the initial assessment of a patient with persistent pain after an ankle sprain. However, as routine X-rays can fail to identify up to half of cartilage defects identified by other means, patients with severe pain lasting 8–12 weeks or longer should have magnetic resonance imaging (MRI). This has an increased sensitivity for diagnosis and for characterising defects in preparation for possible surgery.

The stability and location of the defect, and the presence of bone bruising all help with preoperative planning.

What are the treatment options?

Managing bone and cartilage (osteochondral) defects of the talus bone (see above) continues to be a challenge. There is an association between ankle instability and injury for both new and old talus injuries. Early attempts at stimulating healing, whether by curettage and/or drilling and microfracture achieve similar results.

Patients in whom first-choice treatments have failed are candidates for cartilage replacement surgeries such asosteochondral autograft transfer (OATS), autologous chondrocyte implantation (ACI) and matrix-based chondrocyte implantation (MACI). Larger, non-healing lesions are potential candidates for bulk osteochondral allografts.

Researchers are currently investigating more precise patient selection, optimal rehabilitation, techniques performed entirely via arthroscopy, and advanced biomaterials to accelerate healing.

Conservative treatment

Conservative or non-surgical treatment is guided by the potential for a defect (lesion) to heal, and by patient preferences.

Minor, stable injuries can be treated non-operatively by being immobilised and protected from weight bearing for six weeks.

This is followed by a rehabilitation programme involving gradual weight bearing for another six weeks, with a focus on range of motion and ankle strengthening exercises.

Range of motion exercises are important for cartilage healing, as they support the diffusion of nutrients through the fluid in the ankle joint, although they should only performed once the initial injury has stabilised.

Around half of all cartilage injuries will improve or stay the same after 1 year.

Surgical treatment

When different surgical approaches have similar outcomes, the decision over treatment choice is based on individual surgeon preferences, experience, and lesion location and amount of cartilage damage. The initial surgical treatment for most defects involves arthroscopy with debridement (removal of damaged tissue), andmicrofracture.

Regardless of the specific technique, improvement in pain is seen in 85% of people. If the initial microfracture or drilling procedure is not successful, repeat microfracture for continued pain can be effective.

Revision microfracture is used in patients with persistent pain who have imaging results that suggest healing was incomplete but who cannot have more invasive surgical procedures. Repeat microfracture or drilling is a reasonable, low complication procedure for such patients.

Although the goal of drilling and microfracture is to stimulate healing and restoration of hyaline cartilage, defects usually heal with fibrocartilage, which is less organised ‘scar’ cartilage. Patients who have continued pain and swelling after six months of healing and physical therapy should be assessed for other procedures.

Osteochondral autografts

Osteochondral autografts are recommended for patients with talus defects less than 1.5 cm² who are aged less than 50 years, and in whom either non-operative treatment or initial cartilage surgery has failed. Patients with defects in both the tibia and talus or those who have severe deformity cannot have osteochondral autografts.

Autologous chondrocyte implantation

Autologous chondrocyte implantation (ACI) may be used in patients with cartilage defects of the talus, which can be effective after failed previous arthroscopy. Disadvantages include the cost and the need for the ankle bone to be cut (osteotomy) to gain access to the ankle joint.

Matrix-based chondrocyte implantation

Matrix-based chondrocyte implantation (MACI) is similar to ACI. The advantages of MACI include that it is technically easier than ACI and no osteotomy is needed, and it has shown good outcomes in patients with ankle cartilage injuries.

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