Inter-condylar distance is a simple standing measurement used to record the distance between the knees when the ankles are together. It is most commonly used as a practical measure of knee separation in people who appear to have a bow-legged lower-limb alignment, also known as genu varum.
This measurement can be useful in health, fitness, sport, workplace, rehabilitation and performance settings when lower-limb alignment needs to be documented objectively. It may also provide useful context when reviewed alongside gait, balance, squat mechanics, running, jumping, knee range of motion, hip range of motion, ankle range of motion and lower-limb strength results.
Inter-condylar distance should not be used on its own to diagnose a condition or decide whether a person is ready for sport, work or activity. It is a simple alignment-distance measure. If a major, painful, progressive, one-sided or concerning alignment finding is present, the result should be interpreted within the appropriate professional scope and broader assessment context.
For Measurz, the main value is repeatability. Measure the same way each time, record the position and compare the result with the person’s own baseline or relevant clinical context.
Inter-condylar distance is the distance between the medial femoral condyles, or inner knees, when the person stands with the ankles together.
In practical terms, it measures the gap between the knees when the inner ankles are touching.
The result is usually recorded in centimetres.
Inter-condylar distance is typically used when the knees do not touch while the ankles are together. This may describe a bow-legged alignment pattern. If the knees touch and the ankles are separated, inter-malleoli distance is usually the more relevant measurement.
Inter-condylar distance may be used to:
Record lower-limb alignment
Measure the gap between the knees in standing
Track change over time
Add context to gait assessment
Add context to running, jumping or landing assessment
Add context to squat or lower-limb movement assessment
Support paediatric growth and alignment monitoring where appropriate
Compare findings across repeated Measurz assessments
Provide a simple objective value for progress reports
Support communication with clients using clear measurable data
It is most useful when measured consistently over time or when used alongside other lower-limb assessment results.
Inter-condylar distance measures the gap between the knees when the ankles are together.
It may provide useful information about:
Knee separation in standing
Bow-legged alignment profile
Lower-limb alignment context
Change from baseline
Relationship to gait or movement findings
Side-to-side visual asymmetry when combined with observation
Growth or development context in children where appropriate
It does not directly measure:
Bone structure with precision
Tibiofemoral angle
Hip strength
Knee strength
Ankle mobility
Pain source
Injury diagnosis
Cartilage, ligament or meniscus status
Readiness for sport or work
Functional performance
Inter-condylar distance is a simple clinical distance measure, not a complete lower-limb alignment analysis.
To measure inter-condylar distance in Measurz, you will need:
Flexible non-elastic measuring tape, ruler or calliper
Measurz app
Flat standing surface
Clear view of the knees and ankles
Optional skin-safe marker
Notes field for position, footwear and testing conditions
A rigid ruler or calliper may be easier than a flexible tape if the gap is small. A tape measure can still be used if applied carefully without bending or angling.
Explain the purpose of the measurement clearly.
A useful explanation is:
“We are going to measure the distance between your knees while your ankles are together. This helps us record your lower-limb alignment and compare it over time.”
Ask the client to remove shoes where practical so foot and ankle position can be seen clearly. If shoes must remain on, record this in Measurz.
Before testing, record:
Footwear condition
Standing position
Any pain or discomfort
Whether the person can stand comfortably
Any major asymmetry
Any reason the result may not compare directly with previous sessions
Ask the client to stand upright on a flat surface.
The client should:
Stand tall and relaxed
Keep weight evenly distributed
Bring the medial malleoli, or inner ankle bones, together
Keep the knees comfortably extended
Keep feet pointing forward as much as practical
Avoid forcing the knees inward or outward
Avoid twisting the legs to change the result
The position should be natural and repeatable.
Check that the inner ankles are touching or as close together as comfortably possible.
Do not force the ankles together if this causes pain or discomfort. If the ankles cannot touch, record this clearly.
Identify the closest points between the inner knees.
These are usually around the medial femoral condyles.
The measurement should capture the shortest gap between the knees, not a diagonal or slanted distance.
Measure the shortest distance between the medial femoral condyles.
A practical method is:
Keep the person standing with ankles together.
Place the ruler, calliper or tape between the knees.
Measure the shortest distance between the inner knees.
Record the result in centimetres.
Avoid pressing into the skin or changing the person’s knee position while measuring.
For improved confidence, repeat the measurement.
If values differ, check:
Ankle position
Knee extension
Foot direction
Weight distribution
Whether the person moved or rotated
Record the average of two close measurements or the most consistent value based on your protocol.
Enter the result into Measurz with clear notes.
Useful notes include:
Inter-condylar distance value
Measurement unit
Standing position
Ankles together
Shoes on or off
Feet pointing forward or natural stance
Symptoms if relevant
Any positioning limitation
Any reason the result may not compare directly with previous sessions
The main score is inter-condylar distance, usually recorded in centimetres.
A larger value means there is a larger gap between the knees when the ankles are together. A smaller value means the knees are closer together.
Interpretation should consider:
Age
Growth stage
Symptoms
Whether the finding is one-sided or symmetrical
Whether the distance is changing over time
Gait pattern
Foot position
Hip range of motion
Knee range of motion
Ankle range of motion
Lower-limb strength
Balance and functional testing
Sport or work demands
Whether the person can stand comfortably
In children, lower-limb alignment changes naturally with growth. Bow-legged alignment is common in early childhood and often changes over time. In adults, inter-condylar distance may reflect body structure, previous injury, joint shape, long-term alignment or other factors.
Inter-condylar distance should not be used as a stand-alone diagnostic measure.
There are no simple universal norms for inter-condylar distance that apply to everyone.
In children, some clinical references use less than 6 cm as a broad guide for inter-condylar distance, but this depends on age and development. It should not be treated as a universal adult standard.
For most Measurz users, the most useful comparisons are:
The client’s own baseline
Change over time
Whether the finding is symmetrical or one-sided
How the result relates to gait, squat, balance, hop, strength and range of motion findings
If the distance is large, painful, worsening, one-sided or associated with functional concerns, it should be interpreted within the appropriate professional scope and broader assessment context.
Inter-condylar distance can be reliable when measured consistently.
Reliability improves when:
The same standing position is used
The ankles are placed together the same way
Foot position is consistent
The knees are comfortably extended
The same measuring tool is used
The same landmark is used
The same professional performs the measurement
The same unit is recorded
Notes are entered clearly in Measurz
Inter-condylar distance is valid as a simple measure of the knee gap in standing. It does not replace more detailed lower-limb alignment assessment, tibiofemoral angle measurement or imaging when those are required.
Common errors include:
Not keeping the ankles together
Measuring while the feet are turned out differently
Letting the person shift weight to one side
Measuring a diagonal rather than the shortest distance
Forcing the knees or ankles into position
Not recording footwear
Not recording symptoms
Comparing different standing positions
Treating the result as a diagnosis
Limitations include:
It does not measure bone angles directly
It does not explain the cause of alignment
It can be affected by foot position
It can be affected by hip rotation
It can be affected by knee flexion
It does not measure strength or function
It may need broader assessment if findings are concerning
It should not be used alone for sport, work or treatment decisions
Inter-condylar distance may be useful for:
Lower-limb alignment profiling
Tracking knee gap over time
Paediatric lower-limb observation where appropriate
Gait assessment context
Squat and movement assessment context
Running or landing assessment context
Supporting lower-limb Measurz reports
Client education using objective measurements
For example, if inter-condylar distance changes over time and gait, squat or balance results also change, the combined data may provide more useful context than the distance measurement alone.
When recording inter-condylar distance in Measurz, include:
Client name
Test date
Inter-condylar distance value
Measurement unit
Standing position
Ankles together
Shoes on or off
Foot direction
Symptoms if relevant
Whether the finding is symmetrical or one-sided
Any reason the result may not compare directly with previous sessions
For best results, use the same standing setup every time.
Measurz can help organise inter-condylar distance alongside inter-malleoli distance, leg length, knee girth, hip range of motion, knee range of motion, ankle range of motion, strength, balance, hop testing and gait observations.
Inter-condylar distance is the distance between the inner knees when the ankles are together.
It helps describe a bow-legged alignment pattern, also known as genu varum.
The person should stand upright with the inner ankles together, knees comfortably extended and feet pointing forward as much as practical.
Centimetres are usually most practical for Measurz recording.
No. There are broad paediatric reference guides, but there are no simple universal norms for everyone.
No. It is a measurement, not a diagnosis.
Shoes off is usually preferred, but the most important point is to record footwear conditions and repeat them consistently.
No. It should be interpreted alongside other Measurz assessment findings.
Inter-condylar distance measures the gap between the knees when the ankles are together.
It is commonly used to describe bow-legged lower-limb alignment.
There are no simple universal norms that apply to everyone.
In children, broad age-related reference guides exist, but they should be used carefully.
The result is most useful when compared with the client’s own baseline and broader assessment findings.
Inter-condylar distance should not be used as a stand-alone diagnosis or readiness measure.
Alrayes, M. M., Alruwaili, F. N., Alotaibi, A. M., & Alghamdi, A. A. (2023). Towards a better understanding of knee angular deformities: Clinical assessment and radiographic considerations. Archives of Orthopaedic and Trauma Surgery. https://doi.org/10.1007/s00402-023-05153-w
Arazi, M., Öğün, T. C., Memik, R., & Kutlu, A. (2001). Normal development of the tibiofemoral angle in children: A clinical study of 590 normal subjects from 3 to 17 years of age. Journal of Pediatric Orthopaedics, 21(2), 264–267.
Espandar, R., Mortazavi, S. M. J., & Baghdadi, T. (2010). Angular deformities of the lower limb in children. Asian Journal of Sports Medicine, 1(1), 46–53.
Lohman, T. G., Roche, A. F., & Martorell, R. (Eds.). (1988). Anthropometric standardization reference manual. Human Kinetics.
Marfell-Jones, M., Stewart, A., & de Ridder, H. (2012). International standards for anthropometric assessment. International Society for the Advancement of Kinanthropometry.
Saini, U. C., Bali, K., Sheth, B., Gahlot, N., & Gahlot, A. (2010). Normal development of the knee angle in healthy Indian children: A clinical study of 215 children. Journal of Children’s Orthopaedics, 4(6), 579–586. https://doi.org/10.1007/s11832-010-0297-z
