What is Knee Osteoarthritis?

Knee osteoarthritis (OA) is the most common form of arthritis, affecting the smooth cartilage that cushions the bones of the knee joint. Over time, this cartilage thins and breaks down, leading to pain, stiffness, and loss of function. OA is not just 'wear and tear' – it involves joint inflammation, cartilage damage, changes in bone structure, and sometimes swelling due to excess joint fluid.

It is a major health issue in Australia. According to the Australian Institute of Health and Welfare (AIHW), 1 in 5 adults over 45 has OA, with the knee being one of the most commonly affected joints. It is a leading reason for GP visits, physiotherapy referrals, and joint replacement surgery.

What happens in Knee OA?

In a healthy knee, cartilage provides smooth, frictionless movement. In OA:

  • Cartilage wears down, reducing shock absorption.
  • The joint space narrows, and bones begin to rub.
  • Bony spurs (osteophytes) form around the edges of the joint.
  • The lining of the joint (synovium) may become inflamed, producing extra fluid.
  • Muscles around the knee often weaken due to pain and disuse.

This combination results in pain, stiffness, instability, and reduced quality of life.

Common Causes of Knee Osteoarthritis

  • Increasing age (especially over 50)
  • Previous knee injuries such as ACL rupture or meniscus tears
  • Repetitive occupational stress (kneeling, squatting, heavy lifting)
  • High body weight, placing an extra load on the knee
  • Family history of arthritis
  • Weak quadriceps and glutes leading to poor knee alignment

Who is Most Affected?

  • Adults over 50 – prevalence increases with age
  • Women – particularly after menopause, likely due to hormonal and biomechanical factors
  • Athletes – AFL, football, basketball, and netball players often develop OA due to past ligament or cartilage injuries
  • Workers in heavy manual jobs – trades, gardening, mining
  • Australian statistics: Knee OA is a leading cause of joint replacements, with over 50,000 knee replacements performed annually in Australia, most due to OA

Symptoms of Knee Osteoarthritis

  • Ongoing knee pain, often worse with activity and relieved by rest
  • Stiffness, especially in the morning or after sitting
  • Swelling or warmth around the knee
  • Crunching, grinding, or ‘creaking’ sounds (crepitus)
  • Loss of flexibility and reduced ability to squat, kneel, or climb stairs
  • Instability or the knee ‘giving way’ in advanced stages

📞 If knee pain is interfering with your walking, sport, or work, book an assessment at Spinal and Sports Care Bella Vista or Parramatta.

Diagnosis of Knee Osteoarthritis

Clinical Tests

  • Observation of gait and function (walking, sit-to-stand, stairs)
  • Joint line tenderness, stiffness, and swelling
  • Range of motion testing
  • Functional strength assessment

Imaging

  • X-ray: The most common test. Shows joint space narrowing, bone spurs, sclerosis, and deformity.
  • MRI: Used when X-ray and symptoms don’t match, or to check cartilage, meniscus, or bone stress. In Australia, MRI is often bulk-billed for patients under 50 with a GP/specialist referral.
  • Ultrasound: Identifies joint fluid and inflammation, but is not as accurate for cartilage.

📞 Need clarity? Spinal and Sports Care can arrange imaging referrals and provide a complete knee OA assessment.

Treatment Options

Management depends on severity, lifestyle, and goals. Shared decision-making between patient and clinician is vital.

Non-Surgical Management (first-line)

  • Physiotherapy: targeted strengthening of quadriceps, hamstrings, and glutes
  • Exercise programs: GLA:D (Good Life with Arthritis: Denmark) program, proven to reduce pain and improve function – delivered by trained physiotherapists across Australia
  • Weight management: losing 5-10% body weight can significantly reduce pain and disability
    • Cortisone: short-term relief for inflammation
    • PRP (platelet-rich plasma): may help reduce pain in some patients
    • Hyaluronic acid: lubricates the joint; variable evidence, but used in selected patients
    • Stem cell injections: experimental, not routine care

Surgical Management

  • Arthroscopy: limited role in OA, rarely effective for long-term outcomes
  • Partial or total knee replacement: considered for advanced OA when pain and disability remain high despite conservative care.

📞 Considering surgery? Book a consultation at Spinal and Sports Care to explore your options and prepare with prehabilitation.

Role of Physiotherapy

  • Strengthen key muscles to support the joint and reduce pain
  • Improve flexibility and walking mechanics
  • Provide pacing strategies for flare-ups
  • Deliver the GLA:D program and sport-specific modifications
  • Pre-surgery: build strength to improve recovery
  • Post-surgery: guide structured rehabilitation back to daily life and activity

Recovery Timeline

  • Conservative care: many patients improve in 6-12 weeks with physiotherapy
  • Joint replacement: recovery typically takes 3-6 months, with structured rehabilitation

Injury Grading (OA Stages)

  • Early OA: occasional stiffness and pain, minimal X-ray changes
  • Moderate OA: frequent pain, swelling, reduced mobility, clear imaging changes
  • Advanced OA: severe pain, deformity, constant symptoms, major X-ray findings, often requiring surgery

Prevention of Knee Osteoarthritis

  • Maintain a healthy weight
  • Stay active with low-impact sports (cycling, swimming, walking)
  • Strengthen lower limb muscles through regular exercise
  • Manage injuries early to avoid long-term damage
  • Participate in structured prevention programs such as GLA:D or sport-specific injury prevention

📞 Our physiotherapists at Spinal and Sports Care are trained in prevention and rehabilitation programs tailored for athletes and older adults.

Taping and Bracing

  • Patella taping: can reduce pain and improve knee function
  • Elastic knee sleeves: provide comfort and warmth
  • Unloader braces: reduce pressure in one compartment of the knee in selected patients

📞 Ask our team at Spinal and Sports Care about the best taping or bracing options for your knee OA.

When to See a Physiotherapist or Chiropractor

  • Knee stiffness or pain lasting longer than 6 weeks
  • Pain interfering with work, sport, or daily life
  • Recurrent swelling
  • Planning return to activity after injury
  • Preparing for or recovering from knee replacement surgery

📞 Early assessment at Spinal and Sports Care Bella Vista or Parramatta can help reduce pain and prevent long-term disability.

Frequently Asked Questions

A degenerative joint condition where cartilage thins, bones rub together, and pain, stiffness, and swelling develop.

Very common – about 1 in 5 adults over 45 have OA. Over 50,000 knee replacements are performed annually in Australia, most due to OA.

Netball, basketball, Ongoing knee pain, stiffness, swelling, grinding noises, and reduced mobility., and rugby.

Yes. Exercise is one of the most effective treatments. Swimming, cycling, and walking are excellent options.

An evidence-based exercise and education program delivered by physiotherapists in Australia has been proven to reduce pain and improve quality of life in OA.

Yes, Not always. Many patients manage well with physiotherapy, lifestyle changes, and medications. Surgery is for advanced cases.neuromuscular retraining and physiotherapy.

Cortisone helps in the short term. PRP and hyaluronic acid may help selected patients. Stem cell injections remain experimental.

With physiotherapy, many improve within 6-12 weeks. After knee replacement, recovery is usually 3-6 months.

Symptoms usually worsen, mobility decreases, and the risk of falls and disability increases.

Women are more commonly affected after age 55, but men with heavy labour or sports history are also at risk.

Yes. Research consistently shows exercise therapy is one of the most effective ways to manage knee OA.

Glucosamine and chondroitin are sometimes used, but evidence is mixed. Physiotherapy and exercise remain the gold standard.

Low-impact activities such as cycling, swimming, and walking are best. Football and basketball may aggravate symptoms in later stages.

OA tends to progress over time, but strengthening and prevention programs slow its course.

As soon as stiffness or pain is persistent, early management prevents worsening.