Introduction

Do you experience stiffness and locking in your knees and/or elbow joints? It is possible you may be suffering from Osteochondritis Dissecans (OCD). OCD is a poorly understood condition in which a piece of bone and cartilage separates from the rest of the bone and becomes loose in the joint. It most commonly affects children and adolescents, but adults may also suffer from this condition. Most of the time, it responds well to rest and activity modification. Surgery is also an option when this fails. 

What is OCD?

Osteochondritis Dissecans (OCD) is a condition where a lack of blood flow to the bone underneath cartilage in a joint causes the bone to die. A section of bone and cartilage can then separate and break loose into the joint. This can cause pain, stiffness and locking within the joint. OCD primarily occurs in children and adolescents (ages 10-20), but it may also affect adults. OCD can be found in the knee, elbow and ankle joints. 

What causes OCD?

The exact cause of OCD is currently unknown. It has been suggested that repeated trauma to the joint, such as by playing sports, can lead to the condition. Another potential cause may be genetic, with evidence indicating that a fault in a cartilage-building gene may increase the likelihood of developing OCD.¹

What are the symptoms of OCD?

The symptoms of OCD are often vague and vary depending on how far the piece of bone has separated from the joint surface. Symptoms can include:

• Pain and swelling in the joint
• Locking and catching in the joint
• Decreased range of motion, especially difficulty fully straightening the joint
• Stiffness 
• Clicking

How is OCD diagnosed?

Clinical testing 

Diagnosing OCD from patient history and examination alone can be challenging. Certain diagnostic tests can be used to assess the condition. For the knee, the Wilson test can be used; the test produces pain when the tibia is internally rotated while straightening the knee between 90° to 30° and is relieved with tibial external rotation.² For the elbow, the radiocapitellar compression test causes pain with active pronation-supination when the elbow is fully extended.³ However, these tests are generally considered to be unreliable.¹

Imaging

Diagnosis of OCD is primarily made through imaging. 

• X-rays: These can be used to show the size and location of the lesion. However, early changes can be difficult to detect on an X-ray, so other imaging modalities are recommended
• MRI: This is the recommended imaging technique for OCD.⁴ This is because an MRI clearly shows the state of the affected cartilage and makes it easy to tell whether or not the detached bone is within the joint. As MRI scans do not involve any radiation, they are also very useful for imaging children
• CT scan: CT scans can also be used to visualize OCD and are more commonly used for the elbow and ankle.⁴ While they show more detail than X-rays, a normal CT scan does not show the cartilage. Contrast material may be injected as part of the CT scan in order to ensure a view of the cartilage. Since CT scans involve the use of radiation, they are less beneficial for imaging younger patients. CT scans can be useful in assessing how well an OCD fragment has integrated after surgery

Classification

Different grading systems are used when analysing OCD on imaging. 

For X-rays, the following grading system is used:⁴

• Stage 1: There is a small subchondral compression
• Stage 2: There is partial detachment of an osteochondral fragment
• Stage 3: The HTe fragment is completely detached but not displaced
• Stage 4: Loose body visualized.

For MRI, the following grading system is used:⁴

• Stage 1: There is the thickening of the cartilage and low signal changes but no obvious margins of the fragment
• Stage 2: Osteochondral fragment seen with clear margins but no fluid between the fragment and the underlying bone
• Stage 3: There is fluid visible in places between the fragment and the bone
• Stage 4: Fluid is completely surrounding the fragment but the fragment is not displaced
• Stage 5: Loose body is seen

What is the treatment for OCD?

Activity modification and rest

In children and adolescents, most cases of OCD will improve on their own with rest and time off high-impact activities. In knee OCD, a brace may be used for 6-12 weeks in conjunction with physiotherapy. A gradual return to physical activity can then take place. 

Surgical treatment

Surgery may be considered for OCD if conservative treatment has failed, if the detached piece of bone is moving around in the joint or if the detached bone is particularly large.⁵ There are different surgical techniques available to treat OCD and the technique used depends on each individual case.⁶ These include:

• Drilling into the subchondral bone, aims to stimulate new blood vessels and encourage healing of the surrounding bone
• Using pins and screws to hold the lesion in place
• Using a bone and cartilage graft to replace the damaged area and regenerate healthy bone and cartilage

Recovery from surgery involves using crutches for approximately 6 weeks, followed by rehabilitation for 2-4 months to regain strength and movement in the joint. Return to sports should be possible after 4-5 months.⁶

How successful is surgery for OCD?

Overall, when surgery is conducted for OCD, it normally has fairly positive outcomes. Using drilling techniques, 80% of adolescent patients recover well, with 70% or more being able to return to sports⁷. Positive outcomes have also been reported when using pins and screws, with studies showing 93% of people healing to normal according to X-ray.⁸

FAQs?

What are the symptoms of Osteochondritis Dissecans?

The symptoms of OCD are often vague and vary depending on how far the piece of bone has separated from the joint surface. Symptoms can include:

• Pain and swelling in the joint
• Locking and catching in the joint
• Decreased range of motion, especially difficulty fully straightening the joint
• Stiffness 
• Clicking

Can Osteochondritis Dissecans heal on its own?

Yes, in children and adolescents, most cases of OCD will improve on their own with rest and time off high-impact activities. In knee OCD, a brace may be used for 6-12 weeks in conjunction with physiotherapy. A gradual return to physical activity can then take place. In some cases, surgery may be required and this also has positive outcomes. 

Summary

OCD is a poorly understood condition in which a bone and cartilage lesion becomes separated and can dislodge into the joint. It produces symptoms of pain, swelling, and locking and occurs mostly in children and adolescents. Rest and modification of activities are often sufficient to resolve the condition; however, in certain cases, surgery may be required. If you are concerned you or your child may be suffering from this condition, it is important to have it assessed as soon as possible to ensure a good recovery.