Knee pain is one of the most common reasons Australians seek help from a knee surgeon in Sydney. While sports injuries and age-related wear are familiar causes, leg alignment is often overlooked. The way your hips, knees, and ankles line up directly affects how weight is distributed across your knees.
When alignment is balanced, the joint absorbs force evenly. But when the line shifts out of place, as in bowlegs, knock knees, or flat feet, uneven pressure builds. This leads to discomfort and potential long-term changes.
This is something Dr Jonathan Negus, a specialist knee surgeon in Sydney, often explains when helping people understand why their knees may hurt.
How Leg Alignment Affects the Knee Joint
Before looking at individual conditions, it helps to understand the principle that ties them all together. The knee works best when body weight passes in a straight line from the hip to the ankle, known as the mechanical axis. In this alignment, both the inner (medial) and outer (lateral) compartments of the knee share the load.
If that axis shifts, one side takes more stress. Over time, cartilage and ligaments on the overloaded side are worn down faster, leading to pain and increasing the risk of knee arthritis. With this foundation in mind, we can explore how specific alignment patterns contribute to knee problems. Recognising the early warning signs of knee arthritis is especially valuable here, as it highlights when common alignment issues may be starting to impact joint health.
Bowlegs (Genu Varum) and Knee Pain
The first alignment issue to consider is bowlegs, where the legs curve outward, leaving space between the knees when the ankles touch. Mild bowing is common in very young children but usually resolves by age two. When it continues beyond childhood or appears in adulthood, it changes how the knee carries weight.
- Role in pain: Bowlegs overload the inner (medial) compartment, causing cartilage and meniscus tissue in that area to wear down more quickly.
- Causes: Genetic factors, growth plate disturbances, metabolic bone diseases, such as rickets, or progression of arthritis later in life.
- Impact on daily life: Inner knee discomfort after long walks, difficulty climbing stairs, or fatigue with prolonged standing. Uneven shoe wear is typical.
- Long-term outcome: Persistent bowlegs increase the risk of medial compartment osteoarthritis, which may eventually lead to surgical interventions to restore alignment or replace the joint.
Having looked at outward angling, it’s useful to contrast this with its opposite pattern: knees that angle inward.
Knock Knees (Genu Valgum) and Knee Pain
Knock knees occur when the knees angle inward and touch, while the ankles remain apart. This alignment peaks naturally in early childhood (ages three to six) but normally corrects by age seven or eight. If knock knees persist or develop later, they place additional pressure on the joint.
- Role in pain: Knock knees concentrate force on the outer (lateral) compartment. This extra load can also disrupt kneecap tracking, often leading to discomfort in the front of the knee.
- Causes: Bone growth variations, obesity, trauma, or arthritis. In adults, arthritis is the most common cause of worsening inward angling.
- Impact on daily life: Instability when running or squatting, difficulty pivoting or changing direction in sports, and pain on the outer side of the knee.
- Long-term outcome: This alignment pattern is linked with arthritis in the lateral compartment and ongoing issues with kneecap stability.
While bowlegs and knock knees focus on the angle of the legs, the feet also play an important role in alignment. That brings us to flat feet.
Flat Feet (Pes Planus) and Knee Pain
Flat feet happen when the natural arch in the foot is lower than usual or has collapsed, which causes the foot to tilt inward with each step. This motion is called overpronation. While some people have flexible flat feet that cause no issues, rigid or collapsing arches can affect the knee’s natural mechanics.
- Role in pain: When the foot rolls inward too much (overpronation), it twists the lower leg inward as well, shifting the knee out of its normal line and placing extra pressure on the inner part of the joint.
- Causes: Present from birth in some people, or acquired later through tendon weakness, obesity, injury, or age-related changes such as posterior tibial tendon dysfunction.
- Impact on daily life: Aching knees after long periods of standing, shin splints, ankle instability, or hip fatigue. The strain is often worse on hard surfaces or in unsupportive shoes.
- Long-term outcome: Flat feet can intensify other alignment problems and contribute to chronic medial knee pain. Over time, they may also affect posture and cause secondary strain in the hips or back.
With each condition understood, it’s worth considering how they interact with one another.
How These Conditions Interact
Although each alignment issue has its own distinct pattern, they often overlap in practice. Flat feet may make knock knees more pronounced by causing the ankle to roll inward, while bowlegs can affect how the hip and spine absorb force. This interconnectedness is known as the kinetic chain principle: a misalignment at the foot, knee, or hip can trigger problems elsewhere in the leg.
When Alignment Is the Cause of Knee Pain
So how do you know if alignment is contributing to your symptoms rather than injury or overuse? Some useful signs include:
- Clear outward or inward leg shape.
- Pain consistently on either the inner or outer side of the knee.
- Uneven shoe wear.
- Pain that worsens with prolonged standing, running or walking.
If you recognise these patterns, it may be time to seek assessment from your GP or a knee specialist in Sydney.
Addressing Alignment-Related Knee Pain
Management depends on the severity and how much the misalignment affects daily function. Options include:
- Physiotherapy to strengthen the surrounding knee muscles and improve stability.
- Orthotics and footwear to support flat feet and reduce strain.
- Bracing or taping to shift pressure more evenly across the joint.
- Surgery is required in more advanced cases, such as guided growth in children or osteotomy to realign bones in adults.
For people already experiencing advanced arthritis or significant structural damage, procedures such as knee arthroscopy, ligament reconstruction, partial replacement, or total replacement may be required.
At this stage, restoring alignment is crucial. Dr Jonathan Negus provides both traditional and advanced surgical solutions, including robotic-assisted techniques like Mako SmartRobotics™ (CT-based planning) and the VELYS™ Robotic-Assisted Solution (imageless, intra-operative modelling). These systems enhance precision in correcting alignment. Importantly, there is no additional cost for robotic surgery in Dr Negus’s practice or the hospitals where he operates.
Alignment as a Root Cause
Flat feet, bowlegs, and knock knees are more than variations in appearance. They directly influence how your knees manage pressure. Over time, these patterns can lead to predictable areas of pain and increase the risk of arthritis.
Recognising alignment issues early provides an opportunity to reduce strain, protect joint health, and maintain mobility. If knee pain is persistent, consulting with a GP or an orthopaedic knee surgeon in Sydney may help determine whether alignment is part of the problem and what treatment options may be appropriate.
Frequently Asked Questions (FAQs)
1. Can poor leg alignment cause problems in other joints besides the knee?
Yes. Misalignment can affect the hips, ankles, or even the lower back by changing the way forces travel through the body. This is known as the kinetic chain effect, where one issue in the legs can influence neighbouring joints.
2. Do bowlegs, knock knees, or flat feet always need treatment?
Not always. In many children, alignment changes correct naturally as they grow. In adults, mild cases may not cause symptoms. Treatment is usually recommended when pain, instability, or functional problems develop.
3. How is leg alignment assessed in a clinic?
Assessment often includes a physical examination, observation of walking patterns, and in some cases, imaging such as X-rays to measure the degree of angling. This helps guide whether conservative care or surgical intervention might be suitable.
4. Is robotic-assisted surgery useful for alignment-related knee problems?
Yes. When surgery is required, such as in knee replacement, robotic systems like Mako SmartRobotics™ or the VELYS™ Robotic-Assisted Solution can help improve precision in correcting alignment. Dr Negus uses these systems in his practice without additional cost to patients.
5. Who should I see if I’m worried about alignment-related knee pain?
Start with your GP, who can arrange initial tests or refer you to a specialist if needed. For ongoing or complex knee concerns, consulting an orthopaedic knee surgeon in Sydney, such as Dr Negus can provide a clear diagnosis and tailored treatment options.
