M23.052 Cystic meniscus, posterior horn of lateral meniscus, left knee

Name of the Condition

• Cystic meniscus, posterior horn of lateral meniscus, left knee

Summary

A cystic meniscus, posterior horn of lateral meniscus, left knee, is a condition involving a fluid-filled sac within the posterior horn of the lateral meniscus in the left knee. The meniscus is a C-shaped cartilage structure that cushions and stabilizes the knee joint. This condition may cause pain, swelling, and restricted movement in the affected knee.

Causes

Cystic meniscus often develops due to degenerative changes or tears within the meniscus itself. It may also result from repetitive stress or injury to the knee joint, which can trigger fluid accumulation within the meniscal tissue.

Risk Factors

• Active participation in sports involving repetitive knee motions (e.g., soccer, basketball)
• Aging, which contributes to degenerative changes
• Previous knee injuries
• Genetic predisposition to joint abnormalities

Symptoms

• Pain or tenderness in the left knee
• Swelling or a palpable lump on the outer side of the left knee
• Limited range of motion
• Clicking or locking sensation during knee movement

Diagnosis

Diagnosis typically involves a physical examination and patient history, followed by imaging tests such as MRI or ultrasound to visualize the meniscal cyst. Arthroscopy may be used in some cases to confirm the diagnosis and assess the extent of the condition.

Treatment Options

• Rest and physical therapy to strengthen surrounding muscles and improve flexibility
• Aspiration of the cyst to reduce swelling
• Surgical intervention, such as meniscectomy or cyst decompression, if conservative measures fail

Prognosis and Follow-Up

Prognosis depends on the severity of the cyst and associated meniscal damage. Most patients respond well to conservative treatment, but surgical intervention may be necessary for persistent symptoms. Follow-up care includes monitoring for recurrence and gradual return to activity.

Complications

• Persistent pain or instability
• Recurrence of the cyst
• Meniscal tear or degeneration
• Limited mobility if left untreated

Lifestyle & Prevention

• Avoid repetitive high-impact activities that stress the knee
• Maintain a healthy weight to reduce joint load
• Use proper techniques during sports or exercise
• Strengthen surrounding muscles through targeted exercises

When to Seek Professional Help

Seek medical attention if you experience severe or worsening knee pain, swelling, locking, or inability to bear weight. Early evaluation can prevent complications and guide appropriate treatment.

Tips for Medical Coders

Document the specific location (posterior horn of lateral meniscus) and laterality (left knee) to support accurate coding. Include details of imaging findings, clinical symptoms, and treatment approaches to ensure comprehensive medical record documentation.