Overview

Osteochondritis Dissecans (OCD) is a condition that causes the elbow joint to become locally inflamed, causing pain, and changes to the bone and cartilage of the joint. Diagnosis can be made by physical observation, though x-rays and MRIs may be useful to classify the type of OCD and prescribe the correct form of treatment. In the following article we will focus on shedding more light on this issue. 

Who is commonly affected?

This condition normally affects children assigned male at birth more than those assigned female at birth, normally those aged 10+, with paediatric diagnosis offering better outcomes than in those more senior in age. Repetitive use of the joint, for example during sports, gymnastics or painting, can often cause this condition to develop, which is why it is also referred to as “Little League’s Elbow”.^1,2 Notably, retrospective studies have found that patients with OCD have quite low vitamin D levels too, so it is possible that this also contributes to the formation of OCD. The exact cause however is unknown, though many factors are thought to contribute to its formation.³ 

Pathophysiology

Repetitive actions can cause inflammation of the elbow joint, most commonly affecting the immature capitellum (part of the humerus bone), although parts of the radius and ulna  have also been implicated on occasion.² As a result, death of part of the bone may occur, especially due to high-stress compression forces repeatedly causing many microtears.¹ Part of the bone may crack off, or fragmentation may also begin, commonly on the edge of the capitellum.⁴ 

The compression forces may also cause damage to the two arteries which supply this part of the joint, namely the radial recurrent and interosseous recurrent arteries, thus causing death to part of the bone as oxygen and other vital nutrients won’t reach the affected area.¹ 

Interruption of the cartilage in the joint may also occur from the inflammation, which over time can flake off and become ossified as a result of synovial fluid immersion.² These ossifications are loose bodies within the elbow joint which can cause grinding sounds upon bending or extending the elbow and can limit motion further. 

Over time, untreated OCD can develop into degenerative arthritis (aka osteoarthritis), so recognising and treating the issue is of paramount importance.⁴

There is an indication that sometimes genetic makeup of an individual may cause OCD, called familial OCD instead of sporadic. This is due to a mutation in the aggrecan (ACAN) gene, which can affect articular cartilage production and cushioning of the joint.⁶ Some ACAN mutations have also been linked to skeletal deformities like achondroplasia (a form of dwarfism), although autosomal dominant mutations which lead to the replacement of a single amino acid have been linked to OCD.⁵ As previously mentioned, low vitamin D levels are also thought to contribute to OCD.³ Although the exact mechanism is unknown, low levels of bone mineralisation can weaken bones, and low vitamin D levels have also been linked with higher levels of inflammatory markers in many individuals.^8,3 

Symptoms

OCD ordinarily presents as elbow pain in the dominant arm, often after regular physical activity such as overhead lifting or sports. Pain will begin in a subtle manner and spread across the elbow, with limitations in elbow extension experienced. If the OCD is more advanced, then the elbow may lock or produce grinding sounds too.¹ 

Diagnosis

A physical exam may produce tenderness on the outside edge of the elbow, with some limitations in stretching out the arm (elbow extension). The outside edge of the elbow may also be slightly swollen, red, stiff or produce grinding sounds when the joint is used. 

X-rays in the lateral view and anterior-posterior views can aid diagnosis, along with anterior-posterior films with the elbow bent at 45⁰ angle. An MRI can help assess the extent of the oedema, the size of the defect and how much of the cartilage has separated or become ossified in the form of loose bodies in the joint. MRIs can also help detect bony subchondral lesions when they are smaller, undetectable on x-rays, which can lead to an earlier diagnosis of OCD. As the subchondral lesion of OCD normally occurs on  the outer edge, towards the front of the capitellum, MRIs can also help distinguish between OCD and harmless normal variations in bone such as capitellar pseudodefects which appear towards the back of  edge of the capitellum, thus preventing false diagnosis.⁵ OCD presents similarly to Panner’s disease, so differentiating can aid correct diagnosis.¹

Once diagnosed, the OCD can be classified as one of three types:¹

• Type I: When the cartilage is intact, thickened and the subchondral bone lesion is relatively stable
• Type II: When the cartilage is split with some level of joint displacement 
• Type III: When loose bodies are present in the joint

There are other classification systems that physicians may use to organise treatment. Though different classification systems were compared, even the most reliable system only offered a fairly reasonable level of agreement between different physicians, though even this was dependent upon MRI films.⁴ Consequently, too heavy an emphasis should not be laid upon the specific type of classification, but on the specificities observed by the physician and subsequently how they opt to treat the ailment accordingly.

Treatment

Non-operative

Stable lesions without interruption of the cartilage can simply be rested for 3-6 weeks whilst the repetitive activity that caused the lesion is terminated. Non-steroidal anti-inflammatory drugs (NSAIDS) and other forms of analgesia may be used during this time for pain relief. The elbow joint may also be immobilised in a locked or a hinged range-of-motion brace. This is then followed by 3-4 months physiotherapy and slow easing back into regular activities, which altogether offer rehabilitative success in more than 90% of cases. This can however take 6-18 months.¹

However, regular assessment of the lesion is necessary, and any lesions which do not fit the requirements of this a stable type 1 lesion without cartilage interruption will require surgical correction.

Operative

Most commonly, a type of arthroscopy will be carried out. This is a minimally invasive keyhole surgery of the joint. Depending on the type of damage, such as the presence of loose bodies, the stability of the lesion and the level of articular damage, the right techniques can be carried out to correct the issue. The capitellum may be drilled into in this way and the lesion microfractured, or if the lesion is larger or unstable the arthroscopy may be carried out to reduce and fix the lesion. The capitellum drilling or microfracturing offer better outcomes as compared to arthroscopic reduction and fixation, but both are treated the same post-operatively with physiotherapy for 4-6 months, with weight-bearing exercises begun after 2 months.¹

Loose bodies present in the joint are again treated arthroscopically, with the loose bodies removed surgically before displacement and lesions are fixed. This is followed by early range-of-motion exercises, perhaps with a brace, and no weight-bearing exercises for at least 3 months. Strengthening exercises do not begin until range-of-motion exercises can be performed painlessly.¹

Large, uncontained lesions, which may also involve loose bodies in the joint, and involve the radial head, can be treated with a transplant of bone and cartilage, either from a donor or from another part of the patient’s own body. This is then followed by range-of-motion training soon after surgery, with strength and resistance training from 3 months onwards. From the 5th to the 7th month following the operation, throwing is practised in order to ensure that all normal activities can be resumed.¹

Complications

Long-term complications can result from improper healing of the OCD. These include pain, elbow stiffness and a limited range of motion, all of which can prevent the patient from returning to sports at the same level, or sometimes from ever returning.¹ Arthritis may also occur in the joint with inadequate healing/ cessation of inflammation.^1,6

Summary

Osteochondritis Dessicans of the elbow is an inflammatory damage caused to the elbow joint, often after an accumulation of repetitive compression injuries. The exact cause of OCD is unknown, though it is possible many different environmental and hereditary aspects can increase its likelihood. If discovered early then bracing the arm and rest can heal the disorder, though more advanced cases will require surgery. Elbow stiffness, arthritis and limited range of motion can result from untreated or poorly healed OCD so it is important to see your physician as soon as possible, and to follow post-operative advice accurately.