Hip and Knee Osteoarthritis, Part 1: Risk Factors, Symptoms, and Diagnosis
Updated: 5 days ago
Hip and knee osteoarthritis can affect almost every part of daily life. Walking, climbing stairs, getting out of a chair, exercising, and even sleeping may become more difficult. Osteoarthritis affected an estimated 595 million people worldwide in 2020, with the knee being the most commonly affected joint.
I understand these challenges from both sides of the clinical relationship. After living with osteoarthritis in both hips, I eventually underwent a right hip replacement and, years later, a left hip replacement. Those experiences gave me a personal appreciation of the pain, uncertainty, rehabilitation, and important decisions that can accompany OA.
They also reinforced something I have observed throughout more than 30 years of clinical practice: an imaging report does not tell the whole story. Some people remain remarkably active despite substantial joint changes, while others experience significant pain and limitations with less advanced findings.
The Good News
Osteoarthritis is not simply a story of joints wearing out or an inevitable path toward disability. Although lost cartilage cannot currently be restored through exercise or manual therapy, symptoms and function can often improve substantially.
Management may include:
Education about OA and what imaging findings mean
Individualized exercise and progressive strengthening
Maintaining or gradually rebuilding physical activity
Weight management when relevant
Medication or injections when appropriate
Manual therapy to support movement and symptom relief
Joint-replacement surgery when pain and functional limitations remain unacceptable
Manual therapy and exercise should not be described as reversing OA or reliably slowing its structural progression. Their practical value lies in helping people reduce symptoms, improve physical capacity, remain active, and continue participating in the activities that give life meaning.
In Part 1, we will examine what osteoarthritis is, the factors that influence its development, common misconceptions, characteristic symptoms, and how hip and knee OA are diagnosed. Part 2 will focus on conservative treatment, exercise, and strategies for maintaining long-term function.
Article Index
Risk Factors for Hip and Knee Osteoarthritis
Note: Part 2 of this series covers manual therapy and exercise.
What is Osteoarthritis
Osteoarthritis is a condition that affects the entire joint, not simply the cartilage covering the ends of the bones. In the hip and knee, changes may occur in:
Articular cartilage
Subchondral bone beneath the cartilage
Synovium and joint capsule
Ligaments and menisci
Muscles surrounding the joint
Sensory nerves involved in pain
Healthy cartilage contains water, collagen, proteoglycans, and specialized cells called chondrocytes. Together, these components create a smooth, resilient surface that distributes load and allows the joint to move with very little friction.
With OA, the balance between tissue maintenance, breakdown, and repair becomes disrupted. Cartilage may become thinner and less organized, while the underlying bone remodels and may develop areas of increased density, cysts, or osteophytes. The synovium can also become irritated, and the surrounding muscles may lose strength or function as activity decreases.
These changes develop through a combination of mechanical and biological influences. Ageing, previous joint injury, genetics, body weight, muscle capacity, joint shape, metabolic health, and repeated exposure to demanding loads can all contribute. OA is therefore more complex than simple “wear and tear.”
Articular cartilage itself has no direct nerve supply, so cartilage loss does not fully explain osteoarthritis pain. Symptoms may arise from the subchondral bone, synovium, joint capsule, surrounding tissues, and changes in how the nervous system processes signals from the joint. This helps explain why imaging findings and pain severity do not always correspond.
OA can change over time, but progression is not identical or inevitable for everyone. Understanding it as a whole-joint condition creates more opportunities for management, including strengthening, physical activity, education, weight management when relevant, medication, manual therapy, and surgery when appropriate.
Risk Factors for Hip and Knee Osteoarthritis
Osteoarthritis usually develops through an interaction of biological, mechanical, genetic, and lifestyle factors. A risk factor increases the likelihood of OA, but it does not mean that the condition is inevitable or that one factor caused it.
Factors That Cannot Be Changed
Age: OA becomes more common with age as the joint’s tissues become less resilient and their capacity for maintenance and repair changes. However, OA is not simply an unavoidable consequence of getting older.
Genetics and family history: Inherited traits can influence cartilage biology, joint shape, bone structure, and susceptibility to OA. A family history may increase risk, but it does not determine an individual’s outcome.
Sex: Knee OA is more common in women, particularly after midlife. Hormonal, anatomical, metabolic, and biomechanical factors may all contribute.
Joint anatomy: Variations in joint structure can affect how forces are distributed. Hip dysplasia and certain femoroacetabular shapes may increase the risk of hip OA, while knee alignment can influence loading within different compartments of the knee.
Factors That May Be Modified or Managed
Previous joint injury: Significant injuries involving the cartilage, meniscus, ligaments, or bone are among the strongest risk factors for later OA. Anterior cruciate ligament and meniscal injuries are particularly relevant to the knee. Appropriate rehabilitation may improve function and reduce further injury, although it cannot guarantee that post-traumatic OA will be prevented.
Higher body weight: Additional body weight can increase mechanical demand on the hips and knees. Adipose tissue may also influence OA through metabolic and inflammatory pathways. This association is especially strong for knee OA. When appropriate, gradual and sustainable weight reduction can improve pain and function.
Muscle weakness and reduced physical capacity: Weakness may alter joint control and make daily activities more demanding. It can be both a contributing factor and a consequence of pain and inactivity. Progressive strengthening can improve joint support, function, and confidence, even when structural OA is already present.
High cumulative occupational loading: Years of frequent heavy lifting, kneeling, deep squatting, climbing, or other demanding work may increase OA risk, particularly at the knee. This is different from ordinary movement or appropriately progressed recreational exercise, which is generally beneficial for health.
Metabolic health: Diabetes and other metabolic conditions are associated with OA in observational research. Metabolic and inflammatory pathways may contribute, but the relationship is complex and is partly influenced by factors such as age and body weight. Diabetes should therefore be considered an associated health factor rather than a proven direct cause of OA.
Previous joint disease: Inflammatory arthritis is distinct from osteoarthritis. However, previous inflammation or damage within a joint can contribute to secondary OA later in life.
Previous surgery: Surgery itself is not a universal OA risk factor. The underlying injury and procedures that remove or alter important joint structures, such as partial or total meniscectomy, may increase the likelihood of later OA. In other situations, surgery may improve joint stability or function.
Risk Is Not Destiny
Some risk factors can be changed, while others cannot. Even when several are present, they do not reliably predict how much pain someone will experience, whether OA will progress, or how active that person can remain.
Risk factors are most useful when they guide practical decisions. Maintaining strength and regular activity, rehabilitating injuries, managing metabolic health and body weight when relevant, and modifying excessive occupational loads may support long-term joint health without creating fear of normal movement.
Common Myths About Osteoarthritis
Osteoarthritis is common, but many outdated beliefs about the condition can create unnecessary fear, discourage movement, and make people feel that decline is inevitable. The evidence presents a more hopeful and nuanced picture.
Myth 1: Osteoarthritis Inevitably Gets Worse
Reality: OA does not follow the same course in everyone. Structural changes may progress slowly, remain relatively stable, or change without a corresponding increase in symptoms. Some people with substantial changes on imaging remain active, while others experience significant pain with comparatively modest findings.
No treatment can guarantee that OA progression will stop. However, maintaining strength, physical capacity, a healthy body weight when relevant, and good metabolic health may improve function and help manage factors associated with progression.
Myth 2: There Is Nothing I Can Do About OA
Reality: Although no current treatment can reliably restore lost cartilage or cure OA, much can be done to manage its effects.
Education, individualized exercise, physical activity, weight management when appropriate, medication, injections, and other interventions may reduce pain and improve function. Manual therapy may help some people with pain, stiffness, and movement, particularly when used to support an active rehabilitation program. It should not be presented as reversing OA or preventing structural progression.
Myth 3: Rest Is the Best Treatment
Reality: Short periods of relative rest may be appropriate during a painful flare, but prolonged inactivity can reduce strength, endurance, joint tolerance, and confidence with movement.
Regular movement and appropriately progressed exercise are central components of OA management. Some temporary discomfort may occur when beginning or advancing an exercise program. This does not necessarily indicate additional joint damage. The program may need to be adjusted if pain becomes severe, swelling increases substantially, function deteriorates, or symptoms do not settle as expected.
Myth 4: Sports and Exercise Cause Osteoarthritis
Reality: Normal physical activity and recreational exercise do not automatically cause OA. Regular activity supports muscle strength, cardiovascular health, balance, and the ability to perform everyday tasks.
Joint injury, very high cumulative loading, and certain occupational or elite sporting exposures may increase risk. The injury history and total pattern of loading are often more important than participation in sport itself. Running and other recreational activities may remain appropriate for many people with OA when training load, recovery, symptoms, and physical capacity are considered.
Myth 5: Severe Changes on an X-ray Mean Severe Disability
Reality: Imaging findings and symptoms do not always correspond closely. An X-ray may show considerable joint-space narrowing or osteophytes in someone who remains active, while another person may experience substantial pain with less pronounced structural change.
Treatment decisions should therefore be based on the whole person, including symptoms, examination findings, strength, mobility, activity limitations, health status, and personal goals. The image describes the joint, but it does not determine the person’s future.
Common Signs and Symptoms of Hip and Knee Osteoarthritis
Hip and knee osteoarthritis can present differently from one person to another. Symptoms may fluctuate, and their intensity does not always correspond with the amount of structural change seen on imaging.
Common features include:
Pain related to walking, stairs, prolonged standing, or other joint-loading activities
Stiffness after waking or remaining in one position
Reduced joint movement
Difficulty with everyday activities
Intermittent swelling or a sense of fullness around the joint
Crepitus, which may feel or sound like grinding, clicking, or crackling
Reduced strength, balance, or confidence in the affected leg
Crepitus is common and does not necessarily indicate that the joint is being damaged during movement. Similarly, restricted motion, tenderness, or bony enlargement may support a diagnosis of OA, but no single finding confirms it.
Common Features of Knee Osteoarthritis
Knee OA may produce:
Pain during walking, squatting, kneeling, climbing stairs, or rising from a chair
Brief morning stiffness, commonly lasting less than 30 minutes
Stiffness after sitting or inactivity
Tenderness along the joint line or surrounding structures
Crepitus during knee movement
Intermittent swelling
Reduced flexion or extension
Bony enlargement in more established OA
A sensation of weakness, instability, or the knee “giving way”
Pain may be felt in one region of the knee or across several areas. Symptoms can also arise from the patellofemoral joint, tibiofemoral joint, menisci, tendons, bursae, or referred sources, making clinical assessment important.
Common Features of Hip Osteoarthritis
Hip OA may produce:
Pain in the groin, front or side of the thigh, buttock, or occasionally the knee
Difficulty walking, climbing stairs, entering a vehicle, or rising from a low chair
Difficulty putting on shoes and socks
Stiffness after rest or upon waking
Reduced hip movement, particularly internal rotation and flexion
Pain near the end of the available range of motion
A shorter stride, limp, or other change in walking pattern
Reduced strength around the hip and pelvis
Loss of internal rotation is a common clinical finding, but fixed measurements such as internal rotation below 15 degrees or hip flexion below 115 degrees come from specific classification systems. They should not be treated as universal diagnostic thresholds.
Symptoms and Examination Findings Must Be Considered Together
In adults aged 45 and older, activity-related joint pain combined with no morning stiffness, or stiffness lasting no longer than approximately 30 minutes, may support a clinical diagnosis of OA. Imaging is not always required when the presentation is typical.
Long-lasting morning stiffness, marked warmth or redness, rapid swelling, fever, unexplained weight loss, significant trauma, or rapidly worsening symptoms may suggest another condition and warrant further assessment.
The diagnosis should reflect the complete clinical picture, including symptom behaviour, physical examination, functional limitations, health history, and imaging when it is likely to influence management.
Examination and Diagnosis
Hip and knee osteoarthritis can often be diagnosed clinically from a person’s history, symptom pattern, and physical examination. Imaging may provide useful structural information, but it is not routinely required when the presentation is typical.
The purpose of the assessment is broader than confirming OA. It should determine how the condition affects movement and daily life, identify contributing factors, and consider whether another disorder could be causing or adding to the symptoms.
Clinical History
A detailed history may explore:
Where the pain is felt and whether it travels elsewhere
Which movements, positions, or activities provoke symptoms
The duration of morning stiffness
Swelling, locking, catching, or giving way
Changes in walking, balance, sleep, work, or daily activities
Previous injuries, surgeries, inflammatory conditions, and other health concerns
The person’s activity goals and response to previous treatment
Symptoms such as prolonged morning stiffness, a hot or markedly swollen joint, fever, recent significant trauma, rapid deterioration, or unexplained systemic symptoms may suggest an alternative diagnosis and require further investigation.
Physical Examination
The examination should assess the person rather than simply the painful joint.
Depending on the presentation, it may include:
Standing posture and walking pattern
Active and passive range of motion
Strength and muscular capacity
Joint tenderness, swelling, warmth, and crepitus
Balance and functional movements
Tasks such as squatting, using stairs, or rising from a chair
Examination of the lumbar spine, pelvis, or surrounding joints when referred pain is possible
Selected orthopedic tests to investigate other potential sources of symptoms
No single orthopedic test confirms hip or knee OA. Findings become meaningful when they are interpreted alongside the history, symptom behaviour, and functional limitations.
Orthopedic & Neurological Assessment
Hip Examination - Orthopaedic Testing
This video demonstrates a structured hip examination that includes observation, palpation, active and passive range of motion, and selected orthopedic tests. Particular attention may be given to internal rotation, flexion, gait, strength, and whether testing reproduces the person’s familiar symptoms.
Knee Examination - Effective Orthopaedic Testing
This video demonstrates common components of a knee examination, including observation, palpation, range of motion, ligament and meniscal assessment, and functional testing. These findings help distinguish OA-related symptoms from other possible sources of knee pain.
When Neurological or Vascular Testing Is Needed
A complete neurological or vascular examination is not required to diagnose uncomplicated OA. These assessments become important when symptoms suggest nerve involvement, referred pain, impaired circulation, or another condition.
Lower Limb Neuro Examination
A neurological examination may assess sensation, muscle strength, reflexes, and nerve tension when a person reports numbness, tingling, radiating pain, unexplained weakness, or symptoms that may originate from the lumbar spine or peripheral nerves.
Peripheral Vascular Examination - Key Points
A vascular examination may be appropriate when leg pain is associated with walking tolerance, skin or temperature changes, delayed healing, reduced pulses, or other signs of impaired circulation. This helps distinguish musculoskeletal symptoms from peripheral arterial disease and other vascular conditions.
When Imaging Is Helpful
Imaging may be appropriate when:
The presentation is atypical
Symptoms follow significant trauma
Symptoms or deformity worsen rapidly
Another condition is suspected
Surgery or another procedure is being considered
The result is likely to change management
Conventional Radiography
X-rays are generally the first imaging study when imaging is indicated. They can demonstrate joint-space narrowing, osteophytes, subchondral sclerosis, cysts, and changes in bone shape.
Weight-bearing views are particularly useful for assessing the knee because they show the joint under load. Hip assessment commonly includes an anteroposterior view of the pelvis with additional views selected according to the clinical question.
Magnetic Resonance Imaging
MRI provides detailed images of cartilage, bone marrow, menisci, labrum, ligaments, tendons, and other soft tissues. It is not routinely required for straightforward OA but may be useful when symptoms are unexplained, another disorder is suspected, or more detailed information would influence treatment or surgical planning.
MRI frequently reveals structural abnormalities in people without corresponding symptoms. Findings must therefore be interpreted within the clinical context.
Ultrasound
Ultrasound is not usually the primary imaging method for diagnosing hip or knee OA. It may help assess joint effusion, synovial changes, bursae, tendons, and other accessible soft tissues. It can also be used to guide certain injections.
The Scan Is One Part of the Assessment
The severity of changes seen on imaging does not always correspond with pain or disability. Routine repeat imaging is generally unnecessary when symptoms are stable and the result would not change treatment.
An effective diagnosis brings together the history, examination findings, functional limitations, relevant investigations, general health, and personal goals. Treatment should be directed toward the person’s clinical needs, not solely toward the appearance of the joint on a scan.
Differential Diagnosis: When It May Not Be OA
A diagnosis of osteoarthritis should be treated as a working clinical hypothesis. This does not mean the diagnosis is unreliable. It means that healthcare providers continue to assess whether the person’s history, examination findings, response to treatment, and any investigations remain consistent with OA.
Osteoarthritis may also coexist with another condition. Finding OA on an X-ray does not prove that every symptom originates from the joint.
Conditions That Can Resemble Hip OA
Lumbar radiculopathy or referred spinal pain: Irritation of a lumbar nerve root or another spinal structure can produce pain in the buttock, groin, thigh, or leg. Numbness, tingling, weakness, reflex changes, or pain extending below the knee may suggest neurological involvement.
Greater trochanteric pain syndrome: Pain is usually felt over the outside of the hip and may be aggravated by lying on that side, walking, climbing stairs, or prolonged standing.
Femoroacetabular impingement or labral pathology: These conditions may produce groin pain, clicking, catching, or discomfort during hip flexion and rotation.
Osteonecrosis: Also called avascular necrosis, this condition occurs when part of the femoral head loses its blood supply. Risk factors include corticosteroid exposure, substantial alcohol use, previous trauma, and certain medical conditions. Early radiographs may appear normal, making MRI the preferred investigation when suspicion remains.
Fracture or stress fracture: Hip or groin pain following trauma requires appropriate assessment. Insufficiency fractures may occur with minimal trauma, particularly when bone density is reduced.
Conditions That Can Resemble Knee OA
Referred pain from the hip or lumbar spine: Hip disorders can sometimes present primarily as knee pain. Examining the hip and spine may therefore be necessary when the knee findings do not fully explain the symptoms.
Meniscal pathology: A meniscal injury or degenerative tear may produce joint-line pain, swelling, catching, or restricted movement. Meniscal changes are also common on imaging in people without symptoms and may coexist with OA.
Patellofemoral pain: Pain around or behind the kneecap may be aggravated by stairs, squatting, running, or prolonged sitting.
Ligament injury or instability: A history of trauma, recurrent giving way, or clear instability during examination may indicate ligament involvement.
Tendon or bursal disorders: Gluteal, quadriceps, patellar, hamstring, or iliotibial-band-related conditions can produce pain around the hip or knee without the joint itself being the primary source.
Osteochondral disorders: Conditions affecting cartilage and the underlying bone should be considered, particularly in younger people or following injury.
Inflammatory, Crystal, and Infectious Conditions
Gout or calcium pyrophosphate deposition disease: Crystal arthritis can cause sudden episodes of severe pain, warmth, swelling, and restricted movement. Joint-fluid analysis may be needed to identify crystals and exclude infection.
Rheumatoid arthritis and other inflammatory arthritides: Prolonged morning stiffness, multiple swollen joints, systemic symptoms, or persistent warmth may suggest inflammatory arthritis. Rheumatoid factor and anti-CCP antibodies may support the diagnosis, but neither result should be interpreted in isolation. A negative rheumatoid factor does not exclude rheumatoid arthritis.
Septic arthritis: A rapidly developing hot, swollen, and intensely painful joint, particularly with fever or systemic illness, requires urgent medical assessment. Joint aspiration is often required because blood tests and imaging alone cannot reliably exclude infection.
Other Important Considerations
Vascular disease, deep-vein thrombosis, bone tumours, infection, and pain referred from pelvic or abdominal structures are less common but clinically important possibilities. Sudden inability to bear weight, marked swelling or redness, fever, recent significant trauma, rapidly worsening pain, or unexplained systemic symptoms warrant prompt investigation.
Diagnosis Is a Process
Differential diagnosis is not about ordering every available test. It is about identifying which explanation best fits the complete presentation and recognizing when additional investigation is justified.
A well-supported diagnosis integrates:
Medical history and symptom behaviour
Physical and functional examination
Neurological or vascular findings when relevant
Imaging or laboratory testing when indicated
Progress over time and response to treatment
The diagnosis should be reconsidered when symptoms change unexpectedly, fail to follow the anticipated course, or do not respond as expected.
Conclusion: Understanding Hip and Knee OA
Osteoarthritis can affect comfort, mobility, and quality of life, but a diagnosis does not define a person’s future. Symptoms and structural changes vary considerably, and even substantial findings on imaging do not automatically mean severe pain, disability, or an inevitable need for surgery.
An effective assessment considers more than the appearance of the joint. It brings together the person’s history, symptom behaviour, physical examination, functional limitations, general health, and goals. It also considers whether another condition may be causing or contributing to the symptoms.
Although current treatments cannot reverse established osteoarthritis, many people can improve pain, strength, mobility, confidence, and participation in daily life. Surgery can be highly beneficial when symptoms and functional limitations remain unacceptable despite appropriate nonsurgical care, but it is not the only path forward.
In Part 2, we will examine how education, progressive exercise, activity modification, weight management when relevant, manual therapy, and other treatment options can be combined within an individualized management plan. We will also explore the evolving role of Motion Specific Release as an approach designed to support movement, symptom management, and active rehabilitation.
Note: References for this two-part series appear at the end of Part 2.
Disclaimer:
The articles and embedded videos on the MSR website are provided for educational and informational purposes only. They are not a substitute for individualized assessment, diagnosis, or treatment by an appropriately qualified healthcare professional.
Some videos demonstrate clinical examination and manual therapy procedures intended for licensed or regulated healthcare professionals with appropriate training. These procedures should be performed only within the practitioner’s legal scope of practice and should not be attempted as self-treatment.
Viewing or using this content does not establish a practitioner-patient relationship. If you have questions about a medical condition or symptoms that are new, severe, or worsening, consult an appropriately qualified healthcare provider.
MSR is not responsible for decisions made or actions taken solely on the basis of this educational content. For complete information about website use, third-party links, privacy, and legal terms, please review the MSR Terms of Use, Privacy Policy, and full website disclaimer.
DR. BRIAN ABELSON, DC. - The Author
Dr. Brian Abelson is a chiropractor, author, and educator with more than 30 years of clinical experience in musculoskeletal care, rehabilitation, and sports performance. His educational work focuses on musculoskeletal conditions, human movement, sports biomechanics, and evidence-informed approaches to treatment and rehabilitation.
He is the developer of Motion Specific Release (MSR) and Clinical Director of Kinetic Health in Calgary, Alberta, Canada.
Continue Learning with MSR Courses and MSR Pro
For Healthcare Practitioners
Motion Specific Release integrates assessment, clinical reasoning, manual therapy, exercise, and patient education within one adaptable approach to musculoskeletal care.
MSR Pro and MSR courses support different parts of that learning process:
Structured Clinical Education: MSR courses connect applied anatomy and biomechanics with orthopedic and neurological assessment, myofascial procedures, fascial expansions, joint mobilization, manipulation, and rehabilitation.
Hands-On Skill Development: Live training provides opportunities to refine palpation, patient positioning, force application, and clinical decision-making through practice and direct feedback.
MSR Pro Clinical Library: Members receive access to more than 200 MSR procedures, downloadable and fillable clinical forms, examination resources, rehabilitation progressions, and exercise-prescription materials.
Extensive Video Resources: More than 800 videos support examination, treatment procedures, exercise rehabilitation, and clinical application.
Patient Education: A library of 50 condition articles helps practitioners explain common musculoskeletal problems and provide patients with practical information.
Continued Development: Resources are updated as MSR courses and clinical education continue to evolve.
Videos and articles can introduce concepts, but hands-on proficiency develops through deliberate practice, feedback, and experience. MSR is designed to help practitioners connect technique with clinical reasoning and adapt care to the individual rather than apply the same protocol to everyone.
Explore MSR Pro | View Online and Live Courses
Comments