It can feel confusing when only one knee becomes painful while the other feels normal. You might notice stiffness getting out of the car, a sharper ache while climbing stairs, or swelling after a longer walk. These changes can develop gradually or after a clear incident, and they often raise concerns about what is happening inside the joint. A knee surgeon can help assess one-sided symptoms, especially if they persist or begin affecting your day-to-day activities.
Understanding why only one knee hurts can give you clarity and help you decide whether further assessment is needed. This guide explains common reasons for one knee pain, what may contribute to symptoms, and when it may be appropriate to seek medical review.
Dr Jonathan Negus, an orthopaedic knee surgeon in Sydney, supports people with a wide range of knee conditions, including ligament injuries, meniscus tears, osteoarthritis, and joint alignment issues. His approach focuses on evidence-based assessment and treatment planning tailored to your individual presentation.
How Everyday Factors Can Cause Pain in One Knee
Daily habits and activity patterns can place uneven stress on each leg, which means one knee may carry more load than the other. These patterns often develop gradually and may not be obvious until discomfort begins.
Overloading One Side During Daily Activities
Small behaviours can influence pressure through the knee joint. You may favour one leg when standing, climb more stairs at work, kneel frequently for home or trade tasks, or shift your weight to one side when walking.
Repeated side-dominant activities, such as carrying heavy items on one shoulder or always leading with the same leg on stairs, may add extra strain. Even subtle compensations, such as limping after a minor ankle sprain, can increase pressure through the opposite knee. Over time, these patterns can irritate one knee more than the other.
Age-Related Changes That Affect Knees Differently
Cartilage naturally becomes thinner as we age. According to Healthdirect and Australian Government health resources, this process does not always occur evenly. One knee may show earlier signs of joint surface wear, which can lead to stiffness or aching on that side.
Earlier wear may also be influenced by previous injuries, old fractures, or years of favouring one side for physical or recreational activity. These differences may become more noticeable with increased walking, prolonged standing, or changes in daily routines.
Natural Limb Alignment Differences
Your leg alignment can influence how the load is distributed. Bow-leg alignment can increase stress on the inner (medial) compartment of the knee, while knock-knee alignment may affect the outer (lateral) side. These variations often develop gradually and can lead to one-sided symptoms.
Even small alignment differences may influence how the kneecap tracks, how pressure is absorbed during walking, or how the foot strikes the ground. Over many years, these patterns may contribute to cartilage wear, soft tissue irritation, or earlier fatigue on one side.
Common Conditions That Can Affect Only One Knee
A range of conditions can affect one knee at a time, depending on your activities, alignment, and medical history. Understanding these possibilities can help guide whether further investigation may be helpful.
Early or Localised Knee Osteoarthritis
Localised knee osteoarthritis can affect a single compartment of the knee, such as the medial, lateral, or patellofemoral area. This means only one knee may be symptomatic even if both have some degree of age-related change. Healthdirect notes that osteoarthritis symptoms can vary widely between individuals and joints.
Localised wear may present as morning stiffness, aching during longer walks, or difficulty with stairs. Swelling or warmth may also occur when the joint becomes irritated. Some people notice symptoms fluctuate, with periods of improvement followed by flare-ups depending on activity.
Meniscus Tears and Joint Surface Injuries
A twisting movement, deep squat, or awkward step can irritate or cause a meniscus tear on one side. Sometimes this occurs without a clear injury, particularly if the meniscus has weakened over time.
Symptoms may include sharp pain with certain movements, difficulty straightening the knee fully, or a feeling of catching. Imaging, such as MRI, may be recommended if your GP or knee specialist needs more clarity. A joint surface injury, such as a small cartilage defect, may cause similar symptoms and can also affect only one knee.
Ligament Injuries Such as ACL or MCL Tears
Ligament injuries often affect only one knee. These may occur during sport, sudden directional changes, slips, or falls. An ACL injury may cause instability or difficulty pivoting, while an MCL tear may cause pain along the inner aspect of the knee.
Dr Jonathan Negus frequently manages ligament conditions, including ACL reconstruction, when this is considered appropriate based on your injury and goals. Some ligament injuries may heal with rehabilitation, while others may contribute to long-term load changes in the affected knee.
Patellofemoral Pain or Tracking Issues
Your kneecap relies on the surrounding muscles and soft tissues to keep it aligned. If the kneecap tracks slightly differently on one side, this can lead to patellofemoral pain during stairs, squatting, or prolonged sitting.
Muscle imbalance, foot posture, hip strength, and limb alignment can all influence kneecap movement. Patellofemoral symptoms often fluctuate, sometimes easing with periods of rest and returning with higher activity loads.
Bursitis or Tendon Irritation
Inflammation around the knee joint, including pes anserinus bursitis or patellar tendinopathy, can occur on one side following increased activity, kneeling, or repetitive load. These conditions may cause localised tenderness, warmth, or swelling.
Activities such as running downhill, climbing stairs, or kneeling on firm surfaces may aggravate symptoms. Tendon irritation may also develop when training routines change suddenly or when muscle strength does not match the demands placed on the knee.
Could Past Injuries or Surgery Cause One-Sided Knee Pain
Previous injuries or surgery can influence how one knee functions over time. These changes may affect how you walk, how your muscles activate, or how load is distributed across the joint.
Previous Trauma or Strains
Old sprains, impacts, or untreated injuries may alter joint mechanics. These changes can contribute to ongoing discomfort, stiffness, or swelling on one side.
Even injuries from years earlier may influence how the knee behaves, particularly if the joint surface was affected or if movement patterns changed during recovery. Minor injuries that did not require treatment at the time may still contribute to uneven loading later in life.
Post-operative Changes
After procedures such as knee arthroscopy or ligament reconstruction, one knee may move differently for a period of time. This does not mean symptoms will necessarily persist, but it may create temporary loading differences between sides.
Scar tissue, changes in muscle strength, or protective movement habits can influence how pressure is absorbed. Rehabilitation can help restore balance, but some people continue to favour the stronger knee during daily activities or sports.
When One Knee Hurts More Due to Whole-Body Factors
The knee forms part of a larger movement chain, so issues elsewhere in the body can contribute to one-sided symptoms. These factors may develop slowly and may not be obvious without assessment.
Hip, Foot, or Lower Back Issues Affecting One Knee
Changes in hip strength, flat feet, or lower back conditions can influence how forces travel through the leg. These factors may increase the load on one knee, especially during walking or exercise.
For example, reduced hip stability can cause the knee to roll inward, while changes in foot posture may alter shock absorption. Lower back stiffness can also affect stride length and how weight is transferred from step to step.
Subtle Strength or Mobility Differences Between Legs
If one leg is weaker or less flexible, the opposite knee may compensate. Weak quadriceps, tight calf muscles, or reduced balance control can all place additional stress on a single knee.
These differences may become more noticeable with increased activity or new exercise programs. Even small variations in mobility can lead to gradual overload, especially during repetitive tasks.
How a Knee Specialist Assesses One-Sided Knee Pain
A clear diagnosis of knee pain helps guide appropriate treatment. During a consultation, Dr Jonathan Negus will focus on understanding your symptoms, activity levels, and goals. This allows your management plan to be tailored to your condition and daily needs.
Clinical Examination
Assessment usually includes checking alignment, observing your walking pattern, and examining for swelling, tenderness, or restricted movement. The examination may also include testing ligament stability, assessing meniscus-related signs, and evaluating muscle balance around the hip and knee. Understanding which movements reproduce your symptoms can help clarify the likely cause.
Imaging When Appropriate
X-rays may be arranged to assess joint space, alignment, and bony changes. MRI can be considered when a meniscus tear, ligament injury, or cartilage lesion is suspected. Ultrasound may be used for tendon or soft tissue assessment.
If non-surgical measures are not providing relief and knee replacement becomes a consideration, robotic knee replacement surgery may be discussed. Systems such as Mako Total Knee SmartRobotics, which uses CT-based imaging, or the VELYS Robotic-Assisted Solution, which creates an intra-operative model without CT, may support planning and implant positioning.
Discussing Treatment Options
Depending on your condition, treatment may include physiotherapy, activity modification, medications as advised by your GP, or weight management. These measures can help improve joint support and reduce irritation.
If symptoms remain significant, procedures such as knee arthroscopy, ACL reconstruction, partial knee replacement, or total knee replacement may be considered. The decision is based on symptom severity, imaging findings, your goals, and your overall health.
Home Measures That May Relieve Mild One-Sided Knee Pain
Some people find relief with simple steps that reduce strain or support joint movement. These measures may help symptoms settle, particularly when the cause is related to load or mild irritation.
Activity Adjustment
Temporarily reducing movements that provoke symptoms can help calm irritation, especially after increased training or workload. Gradually reintroducing activities, adjusting pace, or alternating high-impact with low-impact exercise may help manage symptoms without stopping movement entirely.
Strengthening and Stretching with GP or Physio Guidance
A structured program designed by a physiotherapist or GP can help build joint support and improve mobility. Programs should be tailored to your condition and ability. Strengthening the quadriceps, gluteal muscles, and calf muscles may improve stability, while gentle stretching can reduce tightness contributing to overload.
Supportive Footwear and Load Management
Stable footwear and thoughtful planning of daily activities may reduce loading through one knee. Using cushioned shoes, orthotics if recommended, or varying your walking surfaces can help distribute forces more evenly. Breaking tasks into shorter periods may also reduce strain.
When to Avoid Self-Managing and Seek Review
If pain persists, interferes with walking, or is associated with swelling, locking, or knee instability, it is advisable to seek medical assessment rather than continuing to self-manage. Symptoms that limit your ability to straighten or bend the knee fully should also be reviewed.
When to See Your GP or a Knee Surgeon in Sydney
It can be helpful to seek professional advice when symptoms do not settle or begin affecting your usual activities. Early guidance supports informed decision-making and helps identify the most suitable treatment path.
Symptoms That May Need Assessment
Signs that may require review include persistent swelling, pain lasting more than a few weeks, difficulty with weight-bearing, or a sensation of the knee giving way or locking. Night pain, sudden instability, or reduced ability to perform daily tasks may also indicate the need for assessment.
Why Timely Assessment Helps Guide Individualised Care
Early assessment supports accurate diagnosis and can help you understand which treatment options may suit your circumstances. This is not about urgency but about clarity and informed decision-making. It can also help prevent ongoing compensatory patterns that place unnecessary strain on the opposite leg or lower back.
Treatment Pathways Depending on the Cause
Your treatment plan depends on the underlying condition and your goals. Management may change over time as symptoms improve or your activity levels shift.
Non-Surgical Options
Non-surgical care may include physiotherapy program, strengthening programs, bracing when recommended, medications prescribed by your GP, and lifestyle adjustments that protect joint load. Weight optimisation, pacing strategies, and modifying certain high-impact activities may also help reduce symptoms.
Surgical Options for Specific Conditions
If structural damage or advanced wear is present, procedures such as meniscus repair, ligament reconstruction, realignment surgery, partial knee replacement, or total knee replacement may be discussed.
When knee replacement surgery is considered, robotic assistance through Mako or the VELYS may support planning accuracy. In Dr Negus’s practice, the use of robotic assistance is provided at participating hospitals with no additional surgical fee specifically for the robotic component.
Estimated surgical fees (Surgeon’s Fee Only) for privately insured patients may typically range from $3,000 to $8,000, depending on your insurer, your specific level of cover, and the hospital you choose. It is crucial to note that this estimate is for the surgeon’s fee only and does not include separate fees charged by the hospital, anaesthetist, or surgical assistant. Costs of robotic knee surgery vary significantly, so it is important to confirm all fee details and potential out-of-pocket expenses directly with your insurer, the hospital, and Dr Negus’s practice.
How Dr Jonathan Negus Supports People With One-Sided Knee Pain
Dr Jonathan Negus is an orthopaedic knee surgeon in Sydney with a subspecialty focus on knee conditions, including sports injuries, degenerative changes, and joint reconstruction. His practice emphasises thoughtful assessment, shared decision-making, and treatment tailored to each person’s circumstances.
This includes both non-surgical and surgical pathways when appropriate. His approach prioritises understanding how your knee symptoms affect daily life so that treatment aligns with your needs, goals, and overall health.
Making Sense of Your One-Sided Knee Symptoms
One-sided knee pain can arise from everyday factors, alignment differences, localised joint changes, or previous injuries. Understanding these possibilities can help you recognise when symptoms might settle on their own and when review may be helpful.
If your knee pain is persistent, worsening, or interfering with your daily activities, speaking with your GP or an orthopaedic knee specialist can provide clarity and support.
Disclaimer: The information on this page is for general education only and is not a substitute for medical advice. Outcomes and recovery can vary between individuals. Always seek personalised assessment and guidance from your GP or a qualified knee specialist before deciding on any investigation, surgery, or treatment.
FAQs About One-Sided Knee Pain
1. Can one-sided knee pain come from nerve irritation?
Yes. Irritation of nerves in the lower back, hip region, or around the knee can sometimes cause discomfort that feels localised to one side. This may present as sharp pain, tingling, or sensitivity. A GP or physiotherapist can help assess whether nerve involvement may be contributing to your symptoms.
2. Could weight differences between my legs cause one knee to hurt more?
Some people naturally load one leg more when standing, walking, or exercising. Over time, this can increase pressure on one knee and lead to discomfort. Improving balance, strength, and walking patterns may help reduce uneven loading.
3. Is it normal for one knee to hurt after increasing my exercise routine?
It can happen when one leg works harder, especially during running, hiking, or strength training. A sudden change in training volume or technique may overstress one knee. Reducing load and gradually progressing your activity can help symptoms settle.
4. Can flat feet or high arches contribute to pain in only one knee?
Foot posture can influence alignment through the leg, which might increase load on one side. This can be more noticeable during long walks or higher-impact activities. A podiatrist or physiotherapist can assess whether foot mechanics are contributing to your symptoms.
5. How long should I wait before seeking help for one-sided knee pain?
If symptoms improve with rest, gentle movement, and simple measures, you can monitor them for one to two weeks. If the pain persists, limits your movement, or is associated with swelling or instability, it is reasonable to seek review from your GP or a knee specialist.
6. Could leg-length differences cause only one knee to hurt?
Yes. Even small differences in leg length may alter how force is distributed across each knee. This can lead to gradual irritation on the longer or more heavily loaded side. A clinician can assess this during a routine examination.
7. When is imaging needed for one-sided knee pain?
Imaging is typically recommended when symptoms persist, when there is suspected structural injury, or when initial assessment suggests that more information is needed. X-rays or an MRI can help clarify the cause. If surgery is being considered, imaging also assists with planning and discussing appropriate options with your surgeon.
