Overview

Osteochondritis dissecans is a disorder affecting joints where the bone beneath the cartilage dies from a lack of blood supply.^1,2 This condition can result in pain and restricted joint movement, caused by the detachment or loosening of bones and cartilage within the joint. These loose fragments may interfere with normal joint function, leading to discomfort and decreased mobility.

Children and teenagers are most commonly affected by osteochondritis dissecans. They can develop symptoms either after a joint is injured or after several months of activity that stresses the joint, particularly high-impact exercises like running and jumping. Though it can also affect other joints like the elbows or ankles, the ailment most frequently affects the knee.

For children with open physis (growth plates), nonoperative treatment options, including limited weight bearing, may be helpful. Patients who have failed conservative measures, have unstable lesions or are older (closed physis) may benefit from surgery.

Anatomy of ankle

The geometrically complex shape of the talus (small bone at the top of the ankle) resembles a frustum, with the anterior (front) portion being broader than the posterior (back) without any muscular attachments. Seventy per cent of the talus is covered in cartilage, which is among the thickest in the body; this has ramifications for osteochondral autografting (a treatment for osteochondritis dissecans). In general, the ankle keeps its tensile strength (ability to stretch and withstand pressure) with time, surpassing the femoral head as we age. Its blood flow is dependent on extraosseous (outside of the bone) blood flow. The talar body and its dome are supplied by several arteries including the peroneal, anterior tibial, and posterior tibial. The ankle talus articulates with the medial malleolus medially, the tibial plafond superiorly, the posterior malleolus posteriorly, and the fibula laterally. The ankle is a highly congruent mortise joint.

Epidemiology

The most common reasons that osteochondritis dissecans in the ankle may occur include:¹

• Ankle fractures (69% of cases)
• Ten per cent of bilateral medial talar dome lesions 
• 70% of ankle sprains

Anatomical position

Medial talar dome

• Usually, there is no prior trauma history
• Posterior lesions are deeper and larger than lateral lesions

Talar dome on the lateral aspect

• Frequently have a traumatic past
• The healing tendency is less
• Mostly displaced and symptomatic
• It can be more central or in anterior areas

Pathophysiology of OCD

Mechanism of injury

Shearing of the lateral talar dome and lateral OLT(osteochondral lesions of the talus) , is caused by ankle inversion (foot turning inwards instead of landing flat on the surface) and dorsiflexion (pulling the toes towards the knee) during axial stress. Shearing of the medial talar dome and medial OLT is caused by ankle inversion, external rotation, and plantar flexion (pointing toes away from the knee) during axial load. Potential repetitive microtrauma produces an ischemic environment (reduced blood flow), and subchondral (below the cartilage) bone loss causes the surrounding cartilage to soften and become disrupted.

Clinical presentation

Past inversion sprain of the ankle

Joint effusion (fluid) palpation during a physical examination seldom causes pain and cavus hindfoot alignment mobility is frequently restricted as a result of tests that cause discomfort or effusion.

Insufficiency or laxity of the ligaments

Failure rates during osteochondral defect treatment are higher when lateral ligamentous insufficiency remains untreated.

Symptoms

• Joint pain, weakness, and/or edema, frequently following physical or sports exercise
• Reduced range of motion (normal distance joint moves), which includes the inability to fully extend the arm or leg. If the separated bone and cartilage move into the joint space this is more likely to occur
• Joint stiffness following a period of relaxation
• A joint that is locked or stuck in one place
• A clicking sound when the joint is moved

Diagnosis

The doctor will evaluate the stability of the joint and conduct a physical examination in order to identify osteochondritis dissecans. Tests such as x-ray or MRI may be prescribed by the physician.

Views recommended for radiographs

The following results may indicate an osteochondral lesion in the talus bone.

• Typical results for the weight-bearing ankle series
• Frequently typical faint lucency or fractured bone

Bone scan recommendations

• Concern for OLT when radiographs are unclear
• Both specific and sensitive
• OLT bone scan results are 94% sensitive and 96% specific, which is useful for assessing subchondral bone and cysts
• Less dependable when it comes to only cartilaginous lesions of nondisplaced OLTs, but it still offers precise lesion information for preoperative planning

MRI recommendations

• Observations such as chronic pain after an injury and ankle sprains that do not get better with time
• Erratic lesions exhibit fluid deep to the subchondral bone, perhaps overestimating the extent of damage
• Lesion stability shows 92% sensitivity and specificity

Treatment

Non-operative

Depending on how serious the injury is, we might start treating OCD with conservative therapy. This is especially useful if the lesion appears stable and is an open wound (children). In adulthood, 50–75% of asymptomatic lesions will heal without fragmentation. The most common non-operative treatments include:

• Modification of activities including resting with a cast
• Anti-inflammatory drugs
• Infusion of corticosteroids
• Physical intervention
• Restricted weight bearing and bracing^1,2

Operative

Reasons for surgical arthroscopy include debridement, marrow stimulation, and removal of the loose fragment. Chronic lesions, less than 1 centimetre (cm) with misplaced fragments on the osteochondral fragments with little bone (low healing potential) can indicate that retrograde drilling and/or bone grafting may be useful. Lesions with a size greater than 1 cm with the cartilage cap intact also require surgical intervention.¹

Osteochondral grafting

Indications for grafting include a lesion size greater than 1 centimetre and misplaced lesions, shoulder lesions salvaged after unsuccessful marrow stimulation or drilling, and autologous chondrocyte (cartilage cell) implantation.

Contraindications

There are a few contraindications for not doing a surgical repair. These include:

• Severe talar osteonecrosis (dead bone)
• Bipolar kissing lesions
• Widespread ankle arthritis

Osteochondral autograft transfer(OAT)

OAT is the term for the movement of cartilage from one area of the joint to another. We remove the healthy cartilage from a non-weight-bearing portion of the bone. After that, we fit the graft's surface area to the defects, leaving the joint surface smooth.³

Osteochondral allograft transplantation surgery

Tissue grafts from cadavers are known as allografts. It is a block of bone and cartilage that can be precisely sculpted to match the shape of the defect before being pushed into position.

Recovery from osteochondritis dissecans surgery

The length and stage of the injury will determine how well an OCD patient recovers from surgery. You should discuss your potential course of recovery with your physician.

The healing process for soft tissues and bones might take up to eight weeks on average. It is required that you wear a cast throughout this period. Physical therapy may eventually be necessary to restore strength and aid in the healing of bones, muscles, ligaments, and tendons.

To guarantee the greatest outcome and shortest recovery, your doctor will design a personalized rehabilitation plan for you.

Prognosis

The likelihood of a full recovery and a return to pre-injury activities increases with a younger patient age. But sports involving repetitive motions, like pitching, may require the patient to give them up.

Osteochondritis dissecans in adults is more likely to require surgery and has a lower chance of recovery. In addition, adults are more likely to develop osteoarthritis in the injured joint.

After a patient heals, osteochondritis dissecans typically do not recur. But occasionally, the illness just appears to get better when the symptoms momentarily disappear. In some situations, symptoms may eventually reappear.

Risk factors

Children and teenagers who play sports vigorously and are between the ages of 10 and 20 are most likely to develop osteochondritis dissecans.

Complications

A complication of all grafting operations is graft failure in which the graft does not live after the transplant. A tiny proportion of people with persistent pain do not get better with treatment. Finally, osteoarthritis in that joint may be more likely if you have osteochondritis dissecans.

Prevention

Osteochondritis dissecans have unknown causes, making prevention challenging. Young athletes can take precautions to safeguard their joints by donning protective gear and pads, for example. They should also stretch and warm up before engaging in strenuous physical activity, as well as stretch and cool down afterwards. They should also practice the correct physical methods for their sport.

Conclusion

Osteochondritis dissecans (OCD) in the ankle is a condition where a fragment of bone and cartilage becomes detached from the joint surface due to inadequate blood supply, leading to pain, swelling, and limited mobility. Diagnosis typically involves imaging studies like X-rays, MRI, or CT scans to assess the extent of the lesion and its impact on joint health.

Treatment options vary depending on the severity of the condition. Conservative approaches such as rest, immobilization, physical therapy, and anti-inflammatory medications may be sufficient for mild cases. However, more severe cases may require surgical intervention, including arthroscopic debridement, drilling, or fixation to remove loose fragments and promote healing. Long-term outcomes are generally favourable with appropriate treatment, although some patients may experience residual symptoms or joint dysfunction. Rehabilitation plays a crucial role in restoring strength, flexibility, and function to the affected ankle. In conclusion, while osteochondritis dissecans in the ankle can be a challenging condition to manage, prompt diagnosis and appropriate treatment can lead to favourable outcomes, enabling patients to return to their normal activities with minimal limitations. Regular follow-up with healthcare providers is essential to monitor progress and address any ongoing concerns.