M11.06 Hydroxyapatite deposition disease, knee

Name of the Condition

• Hydroxyapatite deposition disease, knee

Summary

Hydroxyapatite deposition disease (HADD) of the knee is a condition characterized by the deposition of calcium phosphate crystals (hydroxyapatite) in soft tissues around the knee, leading to inflammation and pain. It typically affects periarticular structures such as tendons, ligaments, or bursae and may cause acute symptoms. Diagnosis relies on clinical evaluation, imaging, and exclusion of other conditions.

Causes

HADD is caused by the deposition of hydroxyapatite crystals in soft tissues around the knee. The exact trigger for crystal formation is not fully understood, but it may occur spontaneously or in association with trauma, overuse, or metabolic conditions. The crystals can provoke an inflammatory response, contributing to symptoms.

Risk Factors

• Repetitive knee motion or overuse.
• Trauma to the knee.
• Metabolic disorders (e.g., diabetes, hyperparathyroidism).
• Advanced age.
• Chronic kidney disease.

Symptoms

• Sudden, severe pain in the knee.
• Swelling and tenderness.
• Limited range of motion.
• Warmth or redness over the knee.
• Pain that worsens with movement.

Diagnosis

Diagnosis is based on clinical presentation, including sudden onset of pain and tenderness in the knee. Imaging (e.g., X-rays, ultrasound) may show calcific deposits. Joint aspiration is rarely performed but can confirm crystal presence if needed.

Treatment Options

• Rest and activity modification to reduce joint stress.
• Nonsteroidal anti-inflammatory drugs (NSAIDs) for pain and inflammation.
• Physical therapy to improve range of motion and strength.
• Corticosteroid injections for severe inflammation.
• Surgical intervention in rare cases with persistent symptoms.

Prognosis and Follow-Up

Most cases of HADD resolve spontaneously within weeks to months. Follow-up may involve monitoring symptoms and functional improvement. Recurrence is possible, especially with repeated trauma or underlying metabolic conditions.

Complications

• Chronic pain or stiffness if inflammation persists.
• Reduced mobility due to joint involvement.
• Rarely, calcific deposits may cause mechanical symptoms or require intervention.

Lifestyle & Prevention

• Avoid repetitive high-impact activities that stress the knee.
• Maintain a healthy weight to reduce joint load.
• Use proper form during exercise or sports.
• Address underlying metabolic conditions to minimize risk.

When to Seek Professional Help

Seek medical attention if knee pain is severe, sudden, or accompanied by swelling, redness, or inability to bear weight. Prompt evaluation is important to rule out other conditions and initiate appropriate management.

Tips for Medical Coders

Document the specific joint involvement (knee) and any associated symptoms or findings. Ensure clinical documentation supports the diagnosis and excludes other conditions with similar presentations. Code M11.06 is specific to the knee and should be used when the condition is localized to this site.