Knee arthritis: symptoms, treatment without surgery, and when to consider replacement

Knee osteoarthritis is one of the most common reasons adults over 50 seek orthopaedic care in Adelaide. It is also one of the most misunderstood: many people assume that because nothing can reverse the underlying cartilage loss, nothing can meaningfully be done. That is not the case.

A wide range of treatments can reduce pain, improve function, and restore quality of life. Understanding which treatments work, what the evidence says, and when surgery becomes the right option can make a significant difference to the outcome.

What is knee osteoarthritis?

The knee has three compartments: the inner (medial) side, the outer (lateral) side, and the kneecap groove (patellofemoral joint). Each surface is lined with articular cartilage, a smooth, durable tissue that allows the joint to move efficiently under load.

Osteoarthritis occurs when that cartilage gradually deteriorates. As the surface wears down, the joint loses its smooth gliding motion. Inflammation develops, bone spurs form, the joint space narrows, and eventually bone can contact bone. This process happens slowly over years, and its pace varies between individuals. Osteoarthritis (degenerative joint disease) is the most common form of knee arthritis and is distinct from inflammatory arthritis (such as rheumatoid arthritis), which is managed differently and typically involves a rheumatologist alongside an orthopaedic surgeon.

Knee arthritis symptoms

Knee osteoarthritis has a recognisable pattern. Early symptoms are often intermittent. As the condition progresses, they become more consistent and more limiting.

Pain with activity: typically felt on the inner side of the knee or around the kneecap. It is characteristically worse with loading activities, walking on uneven ground, descending stairs, getting up from a low chair, or kneeling. It eases with rest initially, but as the condition advances, rest pain and night pain become more common.

Morning stiffness: a period of stiffness after rest, particularly on first waking or after sitting for an extended period, is typical of osteoarthritis. This “gelling” usually eases within a few minutes of movement.

Swelling: the knee may swell after activity, caused by the joint producing excess fluid in response to irritation. Persistent swelling that does not settle with rest warrants assessment.

Reduced range of movement: as arthritis progresses, the knee may lose its ability to straighten fully or bend as far as it once could. In some patients, the knee develops a visible bowing (varus deformity) as one side of the joint wears faster than the other.

How it is assessed

At a first consultation, Dr Mooney will examine the knee, review standing X-rays, discuss the findings, and explain what treatment options are reasonable given the degree of arthritis and the patient’s functional goals. For many patients, the outcome of the consultation is a plan to continue or optimise non-surgical management. For those with advanced arthritis and significant functional limitation, a surgical pathway may be appropriate.

Knee arthritis treatment without surgery

Non-surgical management is the appropriate starting point for most people with knee arthritis, and it can provide meaningful benefit for years, particularly in those with mild to moderate disease.

The research is consistent: exercise-based rehabilitation is the single most effective non-surgical treatment for knee osteoarthritis. The challenge is that it requires effort and consistency, but the payoff in pain reduction and function is genuine and can last years.

Exercise and physiotherapy: the most evidence-supported non-surgical treatment for knee osteoarthritis. Strengthening the muscles around the knee, particularly the quadriceps and hip abductors, reduces the load the joint itself must bear. A well-designed physiotherapy programme can significantly reduce pain and improve function. Exercise in water (hydrotherapy) is particularly useful for patients with significant pain on land.

Weight management: the knee joint bears approximately four to six times body weight during normal walking. A reduction in body weight of 10kg reduces the load on each knee by 40–60kg with every step. For overweight patients, weight reduction is one of the most effective interventions available, and it also reduces the risk of surgical complications if knee replacement becomes necessary in the future.

Anti-inflammatory medications: NSAIDs such as ibuprofen and naproxen can reduce pain and swelling. They should be used at the lowest effective dose for the shortest necessary period, as they carry gastrointestinal, renal, and cardiovascular risks with prolonged use, particularly in older patients.

Knee bracing: for patients with predominantly medial compartment arthritis and varus alignment, an unloader brace can shift load away from the affected compartment and provide meaningful pain relief for walking and activity.

Platelet-rich plasma (PRP) and other injections: PRP injections, where a concentrate of growth factors derived from the patient’s own blood is injected into the knee, are increasingly used for knee osteoarthritis. The evidence is mixed but generally positive for mild to moderate disease. PRP is not currently covered by Medicare or private health insurance in Australia and is an out-of-pocket expense. See PRP and stem cell injections for knee arthritis.

When surgery is considered

Non-surgical treatment has real limits. Clear signs that a knee has progressed beyond adequate conservative management include: rest pain and night pain that consistently disrupts sleep; significantly limited walking distance; inability to perform normal daily activities without significant difficulty; dependence on strong pain medication to function; and radiological evidence of severe joint space narrowing or bone-on-bone contact on standing X-rays.

At this stage, continuing to defer surgery often means accepting unnecessary limitation for months or years. Knee replacement outcomes are generally better when the surrounding musculature is still reasonable and the patient is otherwise healthy (see prehabilitation), both factors that can deteriorate with prolonged pain and inactivity.

Surgical options

Total knee replacement replaces all three compartments of the knee with prosthetic components. It is the appropriate surgical option when arthritis is widespread across the joint. It is one of the most studied operations in medicine, with consistently high rates of patient satisfaction and long-term implant survival. Modern implants are designed to last 20–25 years based on Australian registry data.

Partial knee replacement replaces only the affected compartment of the knee, leaving the healthy cartilage and ligaments intact. It is appropriate for a smaller group of patients where arthritis is genuinely confined to one compartment (see partial or total knee replacement). Partial replacement typically results in a more natural-feeling knee than total replacement and allows faster recovery, but patient selection is critical.

Robotic-assisted knee replacement: Dr Mooney performs both total and partial robotic-assisted knee replacement using the MAKO system at Eastwood Private Hospital and Calvary Adelaide Hospital. The MAKO system uses a pre-operative CT scan to build a 3D model of the patient’s individual anatomy, and provides real-time guidance during surgery to ensure implant positioning matches the plan.

Seeing a knee arthritis specialist in Adelaide

Dr Mooney consults at Eastwood, Tea Tree Gully (North East Health Centre), Woodville, Naracoorte and Mount Gambier.

A GP referral to an orthopaedic surgeon is appropriate when knee pain is significantly affecting daily life and is not responding adequately to non-surgical management. The consultation is informational: it provides an accurate assessment of the knee and a clear picture of what the options are, without any obligation to proceed with surgery.

Common questions