17. Osteochondritis dissecans of the knee joint

Essay 17- Osteochondritis dissecans of the knee joint

• Definition
• Osteochondritis dissecans of the knee is a relatively rare condition, categorized as a form of osteonecrosis affecting the subchondral bone
• A piece of the subchondral bone and articular cartilage detaches from the underlying bone!
• Most commonly seen in the medial femoral condyle!
• Etiology
• Exact etiology is unknown but there are some theories:
• Repetitive micro-trauma
• Ischemia
• Genetic predisposition
• Patients with extreme obesity and elevated body mass index are at increased risk
• Pathophysiology
• Disruption of the epiphyseal vessels, causes ischemia and necrosis at the trauma site
• Consequently, softening, tearing, fissuring, and erosion of hyaline cartilage occurs
• This advances and leads to detachment of the bone and overlying cartilage
• Clanton and DeLee classification
• Type I- Depressed osteochondral fracture
• Type II- Attached fragment with an osseous bridge
• Type III- Detached fragment but no displacement
• Type IV- Detached and displaced fragment
• Symptoms
• Main symptom is pain in knee joint, aggravated by exertion
• Repetitive hydropsy (excessive serous fluid in tissue space/ body cavity)
• Blockages are seen after removal of necrotic region
• Pain disappears and functionality resumes after joint is unblocked, but previous hydropsies remain
• Limited range of motion
• Depending on the chronicity of the lesion, patients may report quadriceps dysfunction and intermittent knee instability
• Diagnosis
• Arthroscopy- gold standard for assessing lesion stability
• X-rays to assess growth plates and locate lesions
• MRI
• DD
• Chondromalacia
• TB
• Meniscus breakage
• Synovitis
• Treatment
• At beginning, decompression is recommended for a continuous period of time
• Cessation of participation in sports
• Immobilization of the knee
• NSAIDs
• Intra-articular application of mucopolysaccharides and corticosteroids
• Arthroscopic surgery can be performed