Osteochondral Lesions of the Talus

A Patient's Guide

Talar dome osteochondral lesions (OCLs) are injuries affecting the cartilage and underlying bone of the talus, a critical bone in the ankle joint. The talus plays a key role in transmitting forces between the foot and the leg. Osteochondral lesions can be caused by acute trauma, repetitive microtrauma, or microvascular changes and can lead to significant pain and dysfunction. Understanding the nature, diagnosis, and treatment of talar dome OCLs is essential for optimal patient outcomes.

Symptoms and Signs

The symptoms of ankle arthritis can vary in severity and may develop gradually or suddenly. They include:

Pain: Patients often report deep, achy pain in the ankle that worsens with weight-bearing activities, such as walking, running, or standing for prolonged periods. The pain may be persistent or intermittent.
Swelling: Swelling around the ankle joint is a frequent symptom, which can occur due to inflammation or fluid accumulation within the joint.
Stiffness: Limited range of motion in the ankle joint may be experienced, particularly after periods of inactivity or in the morning.
Locking or Catching Sensation: Some patients describe a sensation of the ankle joint locking or catching during movement. This can be due to loose fragments of cartilage or bone within the joint.
Instability: A feeling of the ankle giving way or being unstable may occur, especially if the lesion is associated with ligamentous injury or significant cartilage damage.
Tenderness: Palpation of the ankle joint might reveal tenderness over the affected area of the talus, particularly along the medial or lateral aspects.

Investigations

Accurate diagnosis of arthritis involves a combination of history, physical examination and imaging studies. This is critical for effective treatment planning. Investigations may include:

X-rays: Plain radiographs (X-rays) of the ankle may be used in acute injuries to rule out broken bones. They can help identify cysts, or sclerosis although early or small lesions may not be visible on X-rays.
Magnetic Resonance Imaging (MRI): MRI is the most widely used investigation to diagnose talar dome OCLs. It provides detailed images of both the bone and soft tissues, allowing for assessment of the cartilage, subchondral bone, and surrounding structures. MRI can also identify bone edema, cysts, and loose bodies within the joint.
Computed Tomography (CT) Scan: CT scans can be useful in evaluating the extent of bony involvement and the precise location of the lesion. They provide high-resolution images of the bone but are less effective than MRI in assessing cartilage damage. A CT arthrogram is a special type of CT scan, where contrast fluid is injected in to the joint to establish whether a flap of cartilage is displaced.
Bone Scintigraphy: Occasionally, a bone scan may be used to identify areas of increased metabolic activity within the bone, indicating the presence of a lesion. This is less commonly used compared to MRI and CT. A special type of bone scan is known as a SPECT-CT, which combines bone scintigraphy with a CT scan to identify if an OCL is a likely pain generator.

Non-surgical Treatment

Treatment of talar dome osteochondral lesions can be broadly categorized into non-surgical and surgical approaches, depending on the lesion's size, location, and the patient's symptoms and functional demands. This typically involves:

Rest and Activity Modification: Reducing or modifying activities that exacerbate symptoms is crucial. This may involve avoiding high-impact activities and weight-bearing on the affected ankle.
Physiotherapy: A structured physical therapy program focusing on strengthening the surrounding muscles, improving range of motion, and enhancing proprioception can be beneficial.
Medications: Nonsteroidal anti-inflammatory drugs (NSAIDs) may be prescribed to alleviate pain and reduce inflammation.
Injections: Corticosteroid injections into the ankle joint can provide pain relief and reduce inflammation. There is debatable evidence on other injectable agents such as platelet-rich plasma (PRP) or hyaluronic acid injections, so these are less frequently offered.

Surgical Treatment

When conservative measures fail, or the lesion is severe, surgical intervention may be necessary. Surgical options include but are not limited to:

Arthroscopic Debridement and Microfracture: This minimally invasive procedure involves removing loose fragments and creating small fractures in the underlying bone to stimulate the formation of new cartilage. This technique is suitable for small lesions.
Osteochondral Autograft Transplantation Surgery (OATS): In this procedure, a healthy cartilage and bone plug is taken from a non-weight-bearing area of the patient's knee and transplanted into the lesion site. This is typically used for larger defects.
Fixation of Osteochondral Fractures: In children who sustain an OCL with an acutely, displaced fragment, surgical fixation using screws or pins may be indicated to stabilise the fragment and allow it to heal properly.
Chondrogenic Scaffold Surgery: Larger lesions are less effectively treated with microfracture so, the use of scaffolds impregnated with stem cells or PRP may be glued to replace the defective area created by the OCL.
Partial Joint Resurfacing: Older patients with larger lesions are less likely to have success from bone marrow stimulation and regenerative techniques. In such cases, partial joint resurfacing using the EpiSurf or similar implant may be used to re-establish a congruent joint surface.
Joint fusion or replacement: In suitable patients in whom other treatments have failed, either replacing or fusing the joint may be an appropriate option.

Summary

Talar dome osteochondral lesions are a significant source of ankle pain and dysfunction. Accurate diagnosis and appropriate treatment, whether non-surgical or surgical, are crucial for effective management and to prevent long-term complications. Early recognition and intervention can improve outcomes and enhance the quality of life for individuals affected by this condition.