Review Article: Genu Valgum in the Developing Child: Etiology, Evaluation, and Evidence-Based Management

Abstract

Genu valgum is a condition where an individual\'s knees bend inward, touching each other and creating a \"knock-kneed\" look, which may lead to discomfort and difficulties with walking. Commonly known as knock knees, genu valgum is a coronal plane deformity of the lower limb that is often seen in pediatric orthopedic settings. This review focuses on distinguishing between physiological and pathological genu valgum, highlighting the significance of a thorough clinical history, physical examination, and radiographic assessment for accurate diagnosis. Although it is usually a normal variation of growth that appears between ages 2 and 5 and typically resolves on its own by age 7, it is essential to differentiate between physiological and pathological genu valgum to ensure proper treatment. Physiological genu valgum is usually symmetrical, associated with typical height, and seldom leads to functional issues. Conversely, pathological genu valgum can arise from injuries, metabolic conditions (like rickets), skeletal abnormalities, tumors, or systemic illnesses, and is marked by asymmetry, progress that exceeds the anticipated age for correction, or notable functional limitations. The evaluation starts with a thorough clinical history that emphasizes growth, development, family patterns, and dietary habits. A comprehensive physical assessment involves measuring the tibiofemoral angle or the intermalleolar distance, analyzing limb alignment and gait, and checking for rotational deformities or ligament laxity. Imaging is generally utilized only for cases with unusual characteristics, such as asymmetry, abnormal height, or suspected underlying conditions. X-rays, especially long-leg standing images, are useful for determining mechanical axis deviations and assist in planning for surgery. Management typically follows a conservative approach in physiological cases, where observation is the key strategy. Bracing and orthotic devices are generally discouraged due to their limited effectiveness and low adherence rates. For growing children, guided growth techniques like hemi-epiphysiodesis using staples, plates, or screws are preferred, while osteotomy is typically reserved for patients with fully developed skeletons or when rapid correction is essential. In certain cases that necessitate concurrent limb lengthening, external fixators may be used. This review emphasizes the clinical presentation, evaluation, and treatment alternatives for genu valgum in children, with the goal of assisting clinicians in distinguishing benign growth variations from significant underlying problemsand guiding appropriate care to prevent long-term consequences.

Introduction

???? Overview

Genu valgum, or knock knees, is a common lower limb condition in children, typically part of normal development but occasionally indicative of underlying pathology. Most cases are physiologic and self-correct with age, but pathologic forms may cause discomfort, gait issues, and require intervention.

???? Normal vs. Abnormal Development

• Physiologic Genu Valgum:

  • A normal growth phase starting at age 2 and peaking between 3–4 years.

  • Usually resolves by age 7–8 without treatment.

  • No pain, asymmetry, or functional limitations.

  • Obesity may delay resolution due to added joint stress.

• Pathologic Genu Valgum:

  • Persists or worsens beyond expected age.

  • Linked to metabolic disorders (e.g., rickets), genetic conditions, trauma, infection, or obesity.

  • Symptoms include pain, postural instability, altered gait, and joint stress.

  • May lead to long-term complications if untreated.

???? Etiology (Causes)

• Unilateral Genu Valgum: Often pathological; caused by localized trauma, infection, or tumor.

• Bilateral Genu Valgum: Typically physiological but may indicate skeletal or metabolic disorders if persistent.

• Obesity: Adds biomechanical stress, increasing the risk of angular deformities.

• Vitamin D Deficiency (Rickets): Weakens bones, a common historical and present-day cause.

• Rotational Deformities:

  • Intoeing: Common, usually resolves naturally.

  • Tibial Torsion: Developmental; deviations may affect gait and alignment.

• Angular Variations: Influenced by genetics, joint structure (e.g., Q-angle), and biomechanical stress.

???? Assessment & Evaluation

• History and physical examination are primary tools.

• Key assessments:

  • Tibiofemoral angle

  • Intermalleolar distance

  • Rotational profile

  • Gait analysis

• Radiographs:

  • Only in cases of asymmetry, persistent deformity, or suspicion of pathology.

  • Used to evaluate mechanical axis and joint angles.

???? Treatment Protocol

• Observation:

  • For physiologic cases in children <6 years with mild deformities.

• Conservative Management:

  • Weight control, physical therapy, orthotics for mild symptomatic cases.

• Surgical Intervention:

  • Hemiepiphysiodesis (growth modulation): Best for growing children with progressive deformity.

  • Osteotomy: For older children or severe cases; may involve external fixation for gradual correction.

• Post-treatment:

  • Monitoring and rehabilitation are essential to ensure proper limb alignment and prevent recurrence.

???? Key Takeaways

• Genu valgum is common and often harmless in young children but warrants further evaluation if asymmetrical, persistent, or associated with pain or dysfunction.

• Obesity and vitamin D deficiency are modifiable risk factors.

• Early detection and appropriate treatment are crucial for preventing long-term complications like joint degeneration and mobility limitations.

Conclusion

Genu valgum, commonly known as knock knees, is a frequent pediatric issue that often raises concerns among parents, mainly due to its visible deformity in early childhood. However, in many instances, genu valgum is merely a benign, physiological variant of growth and development that usually resolves on its own without any intervention. It tends to be most prominent between the ages of 3 and 5, and typically diminishes as the child matures, particularly by around 7 years old. It is crucial for healthcare providers to reassure parents about this normal developmental trend while also being alert to unusual presentations. Lower limb deformities in children, including genu valgum, can be classified into physiological and pathological types. Physiological genu valgum is symmetrical and non-progressive, generally not affecting functionality. It often appears alongside other normal variations such as flatfoot and ligament laxity. On the other hand, pathological genu valgum is marked by asymmetry, a progressive nature, short stature, or additional systemic symptoms. The causes of these pathological cases can include metabolic bone disorders like rickets, trauma, infections, genetic syndromes, and skeletal dysplasias. These situations often necessitate an in-depth evaluation, which may involve radiographic imaging and, at times, laboratory tests to ascertain the root cause. Assessing genu valgum involves a thorough clinical evaluation that includes developmental history, family medical history, nutritional status, and analysis of the child\'s gait. Measuring the tibiofemoral angle and intermalleolar distance assists in quantifying the deformity, while evaluations of rotational profile and ligamentous laxity help distinguish between true valgus deformities and those caused by rotational issues. Radiologic imaging is typically reserved for children exhibiting warning signs such as asymmetry, significant deformity, or lack of improvement as they age. Management approaches greatly depend on the severity and the underlying cause. Physiological genu valgum usually requires just observation and reassurance. The use of braces or orthotic devices has not consistently proven beneficial and is generally not advised. Conversely, pathological or persistent genu valgum, especially when linked to considerable functional impairments, aesthetic issues, or abnormal mechanical alignment, may call for surgical intervention. Growth modulation methods like guided growth through hemi-epiphysiodesis are preferred for skeletally immature children, whereas osteotomy is an option for older children or those with severe or rigid deformities. Care following surgery, which includes physiotherapy and monitoring for complications like overcorrection or recurrence, is vital for ensuring positive outcomes.

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Copyright

Copyright © 2025 Sakshi Veer, Nilesh Zanzane, Dr. Nitin Gawai, Smita Khedkar , Karan Durge. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.