Osteochondral Defects (OCD) of the Knee in Children
An osteochondral defect is damage to the joint cartilage and underlying bone. In children, this usually results from trauma or repeated stress on a specific area of cartilage, particularly around the kneecap.
Common locations
- Distal medial femoral condyle
- Under the patella
Causes
- Traumatic patellar dislocation
- Repetitive stress (often associated with hamstring tightness)
- Patellar maltracking due to rotational alignment issues or flat feet
Symptoms
- Knee pain and swelling after injury
- Catching or locking sensation
- Restricted movement
The condition progresses through stages:
- Inflammation of the underlying bone
- Loosening of the fragment (may heal if stress factors are corrected)
- Fragment detachment causing mechanical locking
Loss of the cartilage fragment may damage the underlying bone and predispose to early arthritis.
Investigations
- Plain X-rays: help locate the lesion but limited in detail
- MRI scan: confirms location, stability, bone inflammation and detects loose fragments or “kissing lesions” in advanced cases
Clinical assessment
- Joint swelling and localised tenderness
- Reduced range of motion
- Assessment of hamstring tightness
- Evaluation for patellar maltracking (hip rotation, flat feet, out-toeing)
Treatment
Management depends on the stability of the lesion and correction of contributing factors.
Address aggravating factors
- Hamstring stretching programme, physiotherapy or serial casting
- Treatment of flat feet with orthotics
- Management of patellar maltracking (physiotherapy ± surgery)
Treatment based on lesion stability
Stable lesion (inflammation only)
- Activity modification and correction of underlying factors
- Monitoring with serial MRI scans
Loosening fragment with intact cartilage
- Retrograde drilling to stimulate healing
- Arthroscopic or mini-open fixation
- Close MRI follow-up to confirm healing
Detached fragment (unstable lesion)
- Arthroscopic/mini-open surgery to retrieve and reattach fragment
- Microfracture of base
- Fixation with absorbable screws or pins
Recovery
- Early range-of-motion exercises encouraged
- Restricted weight-bearing for the first few weeks
- Physiotherapy rehabilitation
- Serial MRI scans to monitor healing
Early recognition and treatment are important to preserve cartilage and prevent future arthritis.
