Knock Knees In Singapore

If you or your child has knees that touch or “knock” together whilst the ankles remain apart when standing, you may be dealing with a condition called knock knees. This common knee alignment issue, medically known as genu valgum, can affect people of all ages and may cause discomfort or mobility concerns if left unaddressed.

Dr Zackary Chua

Senior Consultant Orthopaedic Surgeon (Adult & Paeds)

MBBS (Aus)MMed (SG)MRCS (Glasgow)FRCSEd (Orth)

Types Causes & Risks Symptoms When to see a Doctor Diagnosis Treatment Complications Prevention FAQ Conclusion

What is Knock Knees?

Knock knees (genu valgum) is a condition where the knees angle inward and touch each other when standing with feet together, whilst the ankles remain separated. This creates a characteristic “X” shape of the legs when viewed from the front. The condition occurs when the angle between the thighbone (femur) and shinbone (tibia) is greater than normal, causing the knees to bend inward. Whilst mild knock knees are common in young children as part of normal development, persistent or severe cases in older children and adults may require medical evaluation.

Types of Knock Knees

Physiological Knock Knees

This is the most common type, occurring as part of normal childhood development. Children typically develop mild knock knees between ages 3-5, which usually corrects naturally by age 7-8. The knees gradually straighten as the child grows and their walking pattern matures.

Pathological Knock Knees

This type results from underlying medical conditions or bone abnormalities. Unlike physiological knock knees, pathological cases don’t improve with age and may progressively worsen. This type can develop at any age and often affects only one leg or presents asymmetrically.

Post-Traumatic Knock Knees

Develops following injuries to the knee, growth plate, or surrounding bones. Fractures that heal improperly or damage to the growth plates during childhood can lead to angular deformities. This type may appear months or years after the initial injury.

Causes

Genetic factors: Family history of knee alignment issues
Metabolic bone diseases: Rickets or other conditions affecting bone development
Infections: Bone or joint infections during growth periods
Injuries: Growth plate fractures or ligament damage
Bone disorders: Conditions like osteogenesis imperfecta or skeletal dysplasia
Benign tumours: Growth disturbances from bone lesions

Risk Factors

Obesity: Excess weight places additional stress on developing bones
Vitamin D deficiency: Inadequate vitamin D affects bone strength and formation
Premature birth: Early birth may impact normal bone development
Certain medications: Long-term steroid use during growth years
Endocrine disorders: Hormonal imbalances affecting bone metabolism
Nutritional deficiencies: Poor calcium intake or absorption

Signs & Symptoms

Mild Symptoms

Knees touching when standing with feet together
Slight inward angling of the knees
Minor gait changes during walking
Occasional knee discomfort after activity
Shoes wearing unevenly on the inner edges

Moderate Symptoms

Difficulty bringing ankles together when knees touch
Noticeable limp or altered walking pattern
Knee pain during or after physical activities
Increased fatigue when walking longer distances
Difficulty participating in sports or running

Severe Symptoms

Significant gap between ankles (more than 10cm) when knees touch
Persistent knee, hip, or ankle pain
Frequent tripping or falling
Inability to walk without assistance
Progressive worsening of the deformity
Development of arthritis symptoms

Symptoms of knock knees typically become more noticeable as children grow, especially between ages 3-5. In adults, symptoms may gradually worsen over time if the underlying cause isn’t addressed.

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When to See a Doctor

Knock knees that persist beyond age 7–8 in children, or cases where the condition appears more pronounced, can be assessed by a healthcare professional. Significant asymmetry between legs, pain affecting daily activities, or walking difficulties may indicate the need for further assessment. Adults with new or progressive symptoms can also have their knee alignment evaluated.

During the consultation, our orthopaedic surgeon may perform a physical examination, assess walking patterns, and measure knee angulation. X-rays or other imaging may be used to evaluate bone structure and identify any underlying conditions. Appointments typically last 30–45 minutes, allowing time for comprehensive assessment and discussion of findings.

Diagnosis & Testing Methods

Diagnosis typically begins with a detailed medical history and physical examination. The orthopaedic surgeon may observe standing posture, walking pattern, and measure the distance between the ankles when the knees are touching. The intercondylar distance (gap between ankles) helps indicate the degree of knee alignment.

Standing X-rays of both legs are commonly used to measure the angle between the femur and tibia. Normal knee alignment shows a slight valgus angle of 5–7 degrees, while larger angles indicate more pronounced knock knees. Additional tests can include blood work to assess metabolic conditions, vitamin D levels, or inflammatory markers. In complex cases, MRI scans may be used to evaluate soft tissue structures, growth plates, or detect underlying bone variations. CT scans may also be considered for surgical planning in severe cases.

Treatment Options Overview

Conservative Management

Physical therapy is commonly used for non-surgical management of knock knees. Physiotherapists may design exercise programmes focusing on strengthening the muscles around the knees and hips, improving balance, and addressing gait patterns. Specific exercises often target the quadriceps, hamstrings, and hip abductors to support alignment. Sessions are typically attended twice weekly for 6–12 weeks, with home exercises prescribed for daily practice.

Orthotic Devices

Custom shoe inserts or orthotic devices can help redistribute weight and influence lower limb alignment. These devices are often used for mild to moderate cases and growing children. Orthopaedic surgeons may work with certified orthotists to create devices that fit comfortably in regular shoes while supporting alignment.

Bracing

For moderate cases in growing children, specialised knee braces may guide bone growth and alignment. These devices are generally worn during specific hours and adjusted as the child grows. Modern braces are lightweight and designed for comfort during daily activities.

Guided Growth Surgery

This minimally invasive procedure can be considered for children with moderate to severe knock knees who have remaining growth potential. Small plates or screws are placed on one side of the growth plate to slow growth there while allowing the other side to continue, gradually affecting alignment. The procedure typically takes 30–45 minutes per leg and requires only small incisions.

Osteotomy Surgery

For adolescents or adults who have completed growth, corrective osteotomy may be an option. The procedure involves cutting the bone and realigning it to a more neutral angle, then securing it with plates and screws during healing. Modern techniques aim for precise correction with smaller incisions and shorter recovery periods.

Total Knee Replacement

In cases where knock knees are associated with arthritis, total knee replacement may be considered. The procedure addresses joint degeneration and can correct alignment deformities. Orthopaedic surgeons may use specialised techniques and implants designed for complex deformity correction.

Every patient’s condition is unique.

Our Senior Consultant Orthopaedic Surgeon will assess your situation and recommend the most suitable treatment approach for you.

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Complications if Left Untreated

Untreated knock knees can be associated with progressive joint stress and functional limitations. The abnormal alignment may contribute to uneven load distribution on the knee joint, which can accelerate cartilage wear and increase the risk of early-onset arthritis. Some individuals may experience chronic discomfort in the knees, hips, or lower back due to altered biomechanics.

Over time, mobility and participation in certain activities—such as running, jumping, or prolonged standing—may be affected. The altered gait pattern can contribute to muscle imbalances and fatigue. In severe cases, untreated knock knees may result in joint changes that could require surgical intervention. Children with untreated pathological knock knees may experience progressive deformity that becomes more challenging to address as skeletal maturity is reached.

Prevention

While physiological knock knees in children are part of normal development and cannot be prevented, some measures may help reduce the risk of pathological cases or progression. Maintaining a healthy weight can reduce stress on developing bones and joints. Adequate vitamin D and calcium intake through diet or supplements supports bone development.

Regular physical activity contributes to muscle strength supporting knee alignment. Low-impact activities such as swimming or cycling may build strength without excessive joint stress. For children, varied play positions rather than prolonged W-sitting may support healthy hip and knee development. Management of bone infections or injuries can reduce the risk of complications leading to angular deformities. Routine paediatric assessments can help detect potential issues early.

Knock Knees

Frequently Asked Questions

At what age should I be concerned about my child’s knock knees?

Mild knock knees are common in children aged 3-5 years and typically resolve by age 7-8. Persistent knock knees beyond age 8, asymmetrical presentation, or associated pain or difficulty walking may warrant professional assessment. Evaluation can help determine whether intervention is required and provides reassurance for parents.

Can knock knees be corrected without surgery in adults?

Conservative approaches such as physical therapy, weight management, and orthotic devices may help manage symptoms and support knee alignment in mild cases. Surgical correction is generally considered for moderate to severe knock knees. A qualified orthopaedic surgeon can assess the condition and advise on suitable management options.

How long is the recovery after knock knees surgery?

Recovery time depends on the procedure type. Guided growth procedures in children typically allow resumption of normal activities within 2–4 weeks, though devices may remain in place for 12–18 months. Osteotomy surgery usually requires 3–4 months for bone healing, with gradual activity resumption. Total knee replacement often involves 3–6 months of rehabilitation. The surgeon provides a personalised timeline based on individual circumstances.

Will knock knees affect my child’s sports participation?

Children with mild knock knees often participate in sports without issues. Moderate to severe alignment may influence running efficiency and injury risk. Assessment by an orthopaedic specialist can provide guidance on activity considerations during treatment.

Is knock knees hereditary?

Knock knees can have a genetic component, but a family history does not guarantee development. Environmental factors, nutrition, and overall health also contribute. Monitoring helps identify cases that fall outside normal physiological ranges.

What happens during a knock knees consultation?

The consultation typically involves discussion of symptoms and medical history, physical assessment including posture and gait evaluation, and measurement of knee angles. Imaging, such as X-rays, may be used to evaluate bone alignment. The clinician then provides a diagnosis and discusses appropriate management options.

Conclusion

Knock knees, while common in young children, may require professional assessment if persistent or severe. Understanding the condition, its potential causes, and available management options helps families and individuals make informed decisions. Both developmental and adult-onset knock knees have a range of treatment approaches that aim to support alignment, function, and comfort. Timely assessment and appropriate management can help reduce long-term joint stress and improve quality of life.

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Living with knock knees can be challenging, Our Senior Consultant Orthopaedic Surgeon has experience diagnosing and treating knock knees using current evidence-based approaches.

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Dr Zackary Chua (蔡克祥医生)

Senior Consultant Orthopaedic Surgeon (Adult & Paeds)

MBBS (AUS)|MMed (Singapore)|MRCS (Glasgow)|FRCSEd (Orth)

A senior consultant orthopaedic surgeon with dual specialisations in Foot & Ankle Surgery and Paediatric Orthopaedics. Backed by his extensive years of training and experience, Dr Chua brings the necessary knowledge and skills to ensure a smooth recovery journey.

Rooted firmly by two fundamental philosophies: “When one’s feet hurt, one hurts all over” and “Children are not little adults”, Dr Chua’s approach to patient care reflects his compassionate care for adults and children.

Singhealth Quality Excellence Award – Silver (2011)
Service From the Heart Award (2021)
Singapore Health Quality Service Award – Gold (2023)
NUS Medicine Dean’s Award for Teaching Excellence (2023)

His active participation in the medical community extends to mentoring, research supervision, and contributions to key professional forums and symposiums, both locally and internationally.