Scoliosis Cobb Angle Calculator

Interpret scoliosis Cobb angle measurements, estimate progression risk, and determine treatment recommendations.

Current Cobb angle (°)

Prior Cobb angle (°)

Months between measurements

Patient age (years)

Risser sign (0-5)

Curve location (0-2)

Sex (0=Male, 1=Female)

Tab to move between fields

Severity (0-4)

Progression risk (%)

Progression rate (deg/year)10

Treatment recommendation (0-3)1

Bracing window open? (0/1)1

Follow-up interval (months)4

Projected angle in 1 year (deg)35

SeverityModerate scoliosis — bracing indicated if growing

Is Progressing1

Lonstein22

How to Use This Calculator

Enter the Current Cobb angle in degrees as measured on the most recent standing AP spine X-ray.
Enter the Prior Cobb angle and Months between measurements to calculate the progression rate.
Enter the patient's Age in years and Risser sign (0 = skeletally immature to 5 = mature) — lower Risser means higher risk of progression.
Select Curve location (0 = thoracic, 1 = thoracolumbar, 2 = lumbar) and patient Sex (0 = male, 1 = female).
Review Severity classification, Progression risk (%), Treatment recommendation (observe/brace/surgery), and projected angle in 1 year if progression continues.

How the result changes with Current Cobb angle (°)

Current Cobb angle (°): Current measured Cobb angle in degrees.
Prior Cobb angle (°): Previous Cobb angle measurement for progression tracking.
Months between measurements: Time between the two angle measurements.
Patient age (years): Patient age in years.
Risser sign (0-5): Risser sign for skeletal maturity (0=immature, 5=mature).
Curve location (0-2): 0=Thoracic, 1=Thoracolumbar, 2=Lumbar.
Sex (0=Male, 1=Female): Patient sex (females have higher progression risk).

Severity (0-4): 0=Normal, 1=Mild (<25), 2=Moderate (25-39), 3=Moderate-severe (40-49), 4=Severe (>=50)
Progression risk (%): Estimated probability of curve progression based on Lonstein-Carlson method.
Progression rate (deg/year): Rate of curve change based on serial measurements.
Treatment recommendation (0-3): 0=Observe, 1=Brace, 2=Surgical consultation, 3=Surgery likely
Bracing window open? (0/1): 1 if patient is in the effective bracing window (Risser <=2, angle 20-45).
Follow-up interval (months): Recommended interval between imaging follow-ups.
Projected angle in 1 year (deg): Estimated Cobb angle in 1 year if current progression rate continues.

Identify Input Parameters
4 parameters
Current Cobb angle (°) = 25, Prior Cobb angle (°) = 20, Months between measurements = 6, Patient age (years) = 13 = 7 input(s) provided
Calculate Severity
2 = 2
Calculate Progression risk
94 = 94
Calculate Progression rate
Progression rate
10 = 10
Calculate Treatment recommendation
1 = 1