Femoral Retroversion: Assessment, Clinical Importance, and Management

How Do You Assess Femoral Retroversion?

Assessing femoral retroversion primarily involves a combination of clinical observation, specific range of motion tests like Craig's Test, and gait analysis to infer the rotational alignment of the femur relative to the hip and knee joints.

Understanding Femoral Retroversion

Femoral retroversion refers to a rotational alignment anomaly of the femur, specifically when the femoral neck is rotated posteriorly relative to the femoral condyles at the knee. In simpler terms, it describes a "backward" twist in the thigh bone. The opposite condition, femoral anteversion, involves an anterior or "forward" twist. Normal femoral torsion (anteversion) typically ranges from 10-20 degrees in adults, allowing for optimal hip mechanics. Deviations from this range, such as excessive retroversion (e.g., less than 0 degrees or even negative values), can significantly impact lower limb biomechanics.

Clinical Importance of Assessing Femoral Retroversion

Accurate assessment of femoral retroversion is crucial for several reasons:

• Identifying Biomechanical Deviations: It helps explain compensatory movements in the hip, knee, and foot.
• Diagnosing Musculoskeletal Pain: Retroversion can contribute to conditions like femoroacetabular impingement (FAI), patellofemoral pain syndrome, IT band syndrome, and low back pain due to altered joint loading.
• Guiding Exercise Prescription: Understanding a client's femoral torsion allows fitness professionals and therapists to tailor exercises, modify movements, and provide appropriate cues to prevent injury and optimize performance.
• Pre-Surgical Planning: For orthopedic surgeons, precise measurement is vital for corrective osteotomies.
• Understanding Gait Abnormalities: It can explain persistent out-toeing gait patterns.

Non-Invasive Clinical Assessment Methods

While imaging provides the definitive measure, several clinical tests can infer femoral retroversion. These tests assess the functional range of motion and compensatory patterns.

Gait Observation

• Observation: Observe the individual walking from anterior, posterior, and lateral views.
• Indicators: Individuals with femoral retroversion often exhibit an "out-toeing" gait, where the feet point outward during walking. This is a compensatory mechanism to align the hip joint into a more functional position, even though the hip internal rotation range of motion might be limited.

Thigh-Foot Angle (TFA) / Fick Angle

• Procedure: With the individual lying prone and knees flexed to 90 degrees, measure the angle between the long axis of the thigh and the long axis of the foot.
• Interpretation: A positive angle indicates external tibial torsion, while a negative angle indicates internal tibial torsion. While primarily assessing tibial torsion, it's often considered in conjunction with hip rotation to understand overall lower limb alignment. An increased external Thigh-Foot Angle might indirectly suggest a compensatory external rotation originating higher up, potentially due to femoral retroversion.

Craig's Test (Ryder Test)

• Procedure:
  1. The individual lies prone on an examination table with the knee flexed to 90 degrees.
  2. The examiner palpates the greater trochanter of the femur laterally.
  3. The examiner passively rotates the hip internally and externally by moving the lower leg (like a pendulum).
  4. The hip is rotated until the greater trochanter is at its most prominent or "bulges" laterally, indicating that the femoral neck is parallel to the examination table.
  5. At this point, the angle of the tibia relative to the vertical (or perpendicular to the table) is measured using a goniometer.
• Interpretation:
  • Normal Anteversion: The tibia will typically be positioned at an angle of 8-15 degrees internal to the vertical. This indicates a normal amount of femoral anteversion, where the hip is internally rotated to bring the femoral neck parallel to the table.
  • Femoral Retroversion: If the tibia is positioned externally to the vertical (e.g., 0 degrees or even an external angle), it suggests femoral retroversion. This means the hip needs to be externally rotated to bring the femoral neck parallel to the table. A greater external angle indicates more retroversion.

Hip Range of Motion Assessment

• Procedure: Assess passive hip internal and external rotation in both prone and supine positions with the hip and knee flexed to 90 degrees.
• Indicators: Individuals with femoral retroversion typically present with:
  • Reduced Hip Internal Rotation: Often less than 20-25 degrees.
  • Increased Hip External Rotation: Often greater than 45-50 degrees.
• Consideration: Compare the total arc of rotation (internal + external) between both hips and to normative values. A reduced internal rotation coupled with increased external rotation is a strong clinical indicator of femoral retroversion.

Interpreting Assessment Findings

It's crucial to interpret these findings in context:

• Craig's Test Values:
  • Normal: 8-15 degrees of internal rotation (tibia positioned internally).
  • Excessive Anteversion: Greater than 15-20 degrees of internal rotation.
  • Retroversion: Less than 8 degrees of internal rotation, 0 degrees, or even external rotation (tibia positioned externally).
• Symmetry: Compare findings between both legs. Asymmetry can be significant.
• Compensatory Mechanisms: Understand that the body will compensate for rotational deformities. For example, an individual with femoral retroversion might compensate by externally rotating their tibia or foot during gait to make their feet point straight ahead, masking the underlying retroversion.
• Clinical Picture: Integrate assessment findings with the client's symptoms, pain patterns, activity levels, and other orthopedic findings.

Limitations of Clinical Assessment

While valuable, clinical assessments for femoral retroversion have limitations:

• Subjectivity: They rely on examiner skill, goniometer placement, and patient relaxation.
• Soft Tissue Influence: Muscle bulk, capsular tightness, or ligamentous laxity can influence perceived range of motion.
• Accuracy: They provide an estimation of femoral torsion, not a precise anatomical measurement. They infer the bony alignment based on end-range joint motion.
• Inter-Rater Variability: Different examiners may yield slightly different results.

When to Refer for Imaging (Gold Standard)

For a definitive and precise measurement of femoral torsion, imaging studies are the gold standard:

• Computed Tomography (CT) Scan: Considered the most accurate method for measuring femoral anteversion/retroversion. It provides a direct measurement of the angle between the femoral neck axis and the transcondylar axis of the knee.
• Magnetic Resonance Imaging (MRI): Can also be used, though often slightly less precise than CT for this specific measurement.
• When to Refer: Imaging is typically recommended when:
  • Clinical findings are inconclusive or inconsistent with symptoms.
  • Surgical intervention (e.g., derotational osteotomy) is being considered.
  • There is a need to rule out other structural abnormalities.
  • Persistent, unexplained pain or functional limitations despite conservative management.

Implications for Exercise and Rehabilitation

Understanding femoral retroversion significantly impacts exercise prescription:

• Hip Rotation Bias: Individuals will naturally favor exercises that utilize their increased external rotation range.
• Avoid Forced Internal Rotation: Exercises that demand extreme hip internal rotation (e.g., deep squats with knees tracking inward, specific yoga poses) may be contraindicated or require significant modification to prevent impingement or undue stress on the hip joint.
• Form Cues: Emphasize external rotation or "knees out" cues during squats and lunges to align the femur more optimally within the acetabulum.
• Strengthening: Focus on strengthening hip external rotators and abductors, as well as core stability, to support optimal hip mechanics.
• Mobility: While some internal rotation work might be beneficial if limited by soft tissue, avoid aggressive stretching into bony impingement. Focus on maintaining a functional range of motion.
• Activity Modification: Advise on modifications for sports or activities that involve high-impact or repetitive hip rotation.

Conclusion

Assessing femoral retroversion is a critical component of a comprehensive lower extremity biomechanical evaluation. While clinical tests like Craig's Test and range of motion assessments provide valuable insights into functional alignment and compensatory patterns, they serve as clinical indicators rather than precise anatomical measurements. For definitive diagnosis or surgical planning, advanced imaging is necessary. For fitness professionals and kinesiologists, recognizing the signs of femoral retroversion allows for tailored exercise programming that respects individual anatomy, optimizes movement patterns, and mitigates injury risk, ultimately enhancing client outcomes.