Knee Arthritis (Osteoarthritis; OA): Causes, Symptoms, Diagnosis and Treatment in Bath & Bristol

Knee osteoarthritis (OA) is a very common condition where the smooth joint surfaces gradually wear, leading to pain, swelling, stiffness and reduced function. The knee is one of the most commonly affected weight-bearing joints. Osteoarthritis can range from mild, intermittent symptoms to more advanced disease that significantly affects walking, work, sport and sleep.

Mr Simon Abram, Consultant Specialist Knee Surgeon, provides specialist assessment and treatment for knee osteoarthritis in Bath and Bristol. Treatment is tailored to your symptoms, your arthritis pattern, and your goals - from physiotherapy, braces, and injections through to knee-preservation surgery (such as osteotomy) and joint replacement (partial or total, including robotic options in selected cases).

What is knee osteoarthritis?

The knee joint surfaces are lined with smooth cartilage that helps the joint glide and spreads load. With osteoarthritis, the cartilage becomes thinner and rougher over time. The underlying bone may become irritated and develop small spurs. The joint can also become inflamed, which contributes to swelling and pain.

Osteoarthritis is not simply “wear and tear.” It is a whole-joint condition involving cartilage, bone, synovium (joint lining), lubricating joint fluid, and is often associated with damage to the meniscus and ligaments.

What causes knee osteoarthritis?

Knee osteoarthritis usually develops due to a combination of factors. Common contributors include:

Age: OA becomes more common as we get older, particularly over 40
Body weight: higher body weight increases load through the knee and can worsen symptoms
Previous injury: meniscus tears, ligament injuries (such as ACL), fractures, or cartilage injuries can increase risk
Genetics: OA often runs in families
Sex: OA is more common in women than men
Alignment: bow-leg (varus) or knock-knee (valgus) can overload one compartment and drive progression
Meniscus deficiency: loss of meniscus tissue increases cartilage load and can accelerate wear
Occupational and sporting loads: repetitive heavy loading can contribute in some individuals

In some people, there is no clear trigger - osteoarthritis develops gradually over time.

Symptoms of knee osteoarthritis

Symptoms can vary between people and do not always match x-ray severity. Common symptoms include:

Pain (often worse with activity and later in the day)
Stiffness after rest that improves after a few minutes of moving
Swelling or puffiness, especially after activity
Reduced walking distance or difficulty on stairs/hills
Grinding or creaking sensations
Loss of confidence in the knee or a feeling it is unreliable
Sleep disturbance if pain becomes persistent

When to seek urgent assessment

Seek urgent advice if you have sudden severe pain, a hot/red knee with fever, inability to weight-bear, a locked knee, or a major new swelling after injury.

Assessment and diagnosis (Bath & Bristol)

Accurate diagnosis is essential because treatment depends on the arthritis pattern, severity, and your goals. Mr Simon Abram offers specialist knee osteoarthritis assessment in Bristol and Bath.

Assessment usually includes:

History: where the pain is, what triggers it, swelling pattern, activity limits, impact on sleep/work/sport
Examination: range of motion, tenderness, swelling, stability, alignment, and walking pattern
X-rays: usually weight-bearing views to assess joint space and arthritis distribution
Long-leg alignment X-rays (selected cases): to assess load through the leg when osteotomy is being considered
MRI scan (selected cases): to assess cartilage, meniscus, bone changes, and other structures when it changes management

There is no routine blood test to diagnose osteoarthritis. Blood tests may be used only if another diagnosis is suspected.

Understanding arthritis patterns (why the pattern matters)

Knee osteoarthritis often affects one part of the knee more than others:

Medial compartment OA (inner side): common with bow-leg alignment
Lateral compartment OA (outer side): sometimes linked with knock-knee alignment
Patellofemoral OA (kneecap joint): pain around/behind the kneecap, often worse on stairs/hills
Multi-compartment OA: arthritis across more than one compartment

This pattern strongly influences whether knee-preservation surgery is possible and whether partial or total knee replacement is most appropriate.

Treatment options for knee osteoarthritis

Treatment is usually stepwise, starting with non-surgical care and progressing to surgical options when symptoms remain limiting.

1) Education, activity and load management

Understanding triggers and pacing activity
Low-impact fitness (walking plans, cycling - especially on a 'static' exercise bike or turbo trainer, swimming)
Reducing high-impact overload during flare-ups

2) Physiotherapy and strength training

Strengthening is one of the most effective treatments for knee OA. Physiotherapy typically focuses on:

Quadriceps and hip strength
Balance and movement control
Improving walking and stair mechanics
Progressive return to enjoyable activities
Bracing - for example, braces designed to offload the part of the knee with arthritis
Insoles - can work in a similar way to braces

3) Weight management

If you are overweight, even modest weight loss can reduce load through the knee and improve pain and function.

4) Pain relief and anti-inflammatory medication

Medication can help symptoms and support participation in rehabilitation. Options may include simple pain relief and anti-inflammatory medication, depending on your health and suitability.

5) Injections (selected cases)

Injections may provide temporary symptom relief for some patients. The role of injections is individualised and depends on your arthritis pattern, severity and goals.

When surgery is considered

Surgery is considered when symptoms persist despite appropriate non-surgical care and are significantly affecting quality of life. The surgical options depend on the arthritis pattern and the condition of the whole knee.

Knee-preservation surgery (for selected patterns)

Knee osteotomy

Knee osteotomy is used when alignment is overloading one compartment. By correcting alignment, osteotomy can reduce pain and, in many cases, delay the need for joint replacement.

High Tibial Osteotomy (HTO): commonly for medial compartment overload with bow-leg alignment
Distal Femoral Osteotomy (DFO): commonly for lateral compartment overload with knock-knee alignment

Meniscus surgery and meniscus preservation

Meniscus problems can worsen OA symptoms and joint mechanics. Options may include meniscal repair, root repair, partial meniscectomy (trimming), or, in selected cases, meniscal transplant as part of a knee-preservation strategy.

Cartilage treatment

In some knees, focal cartilage defects contribute to pain and function limits. Cartilage procedures (such as chondroplasty, OATS, ACI, and osteochondral allograft in selected cases) may be considered when symptoms are driven by a focal defect rather than widespread arthritis.

Joint replacement options for knee osteoarthritis

When arthritis is advanced or affects multiple compartments, joint replacement may provide the most reliable improvement.

Partial knee replacement

Partial knee replacement may be considered when arthritis is mainly confined to one compartment and the rest of the knee is in good condition. Options include:

Medial partial knee replacement
Lateral partial knee replacement
Patellofemoral joint replacement

Total knee replacement

Total knee replacement is usually considered when arthritis affects multiple compartments or when a partial replacement would not be reliable.

Robotic-assisted knee replacement (selected cases)

In selected patients, robotic assistance can support precision planning and implant placement for partial or total knee replacement. Systems used include Mako and CORI, depending on procedure type, anatomy and availability.

Choosing the right option: what matters most

The best treatment depends on:

Which compartment(s) are affected
Your alignment and knee stability
Meniscus and cartilage status
Your activity goals and expectations
Your general health and ability to commit to rehabilitation

In clinic, you should expect a clear discussion of benefits, limitations, likely recovery, and the alternatives so you can make a confident, informed decision.

Frequently asked questions

Do x-rays always match symptoms?

No. Some people have significant pain with mild x-ray change, and others have more advanced x-ray findings with fewer symptoms. Treatment decisions are based on the whole picture: symptoms, function, examination and imaging.

Can I still exercise with knee osteoarthritis?

Yes. Exercise is one of the most effective treatments. The goal is low-impact, progressive activity that builds strength and improves tolerance, guided by pain response and swelling.

When should I consider a knee replacement?

Knee replacement is typically considered when pain and function are significantly affected despite good non-surgical treatment, and when arthritis severity and pattern suggest a replacement will be the most reliable option.

Is partial knee replacement better than total knee replacement?

Partial replacement can be excellent when arthritis is confined to one compartment. Total replacement is more appropriate when arthritis is widespread. The best option is the one that fits your arthritis pattern and goals.

Can I be assessed for knee osteoarthritis in Bath or Bristol?

Yes. Mr Simon Abram offers specialist assessment and treatment planning for knee osteoarthritis in Bath and Bristol, including non-surgical care, knee-preservation options such as osteotomy, and joint replacement where appropriate.