Total Knee Replacement: What to Expect Before, During and After Surgery

In the majority of patients with end-stage knee arthritis who have exhausted non- surgical management, knee replacement can help to reduce pain, improve function and allow a return to daily activities. At least 85% of patients self-report good-to-excellent outcomes following knee replacement surgery. Understanding what the procedure involves, why it is recommended, and what recovery requires helps patients approach surgery with realistic expectations and a clear plan.

Key Takeaway

Total knee replacement does not remove the knee joint. It resurfaces the worn ends of the bones with precision-engineered components, restoring the smooth articulating surface that arthritis has destroyed. The surrounding ligaments, tendons, and muscles remain intact.

Who Needs a Total Knee Replacement?

Total knee replacement is indicated when knee arthritis has progressed to the point where pain and functional limitation are no longer adequately managed by conservative measures. The decision is not based on age or imaging findings alone. It is based on the relationship between structural damage, symptom severity, and the impact on quality of life.

The conditions that most commonly lead to total knee replacement are:

• Osteoarthritis: The most common cause, characterised by progressive loss of articular cartilage in one or more knee compartments. Early and moderate osteoarthritis is typically managed with activity modification, physiotherapy, weight management, and anti-inflammatory strategies. When these measures no longer provide adequate relief and when imaging confirms significant joint space loss, replacement becomes the appropriate next step.
• Rheumatoid arthritis: Inflammatory joint disease that can destroy the cartilage and bone of the knee more rapidly than osteoarthritis. Surgical planning for patients with rheumatoid arthritis involves additional considerations regarding medication management and bone quality.
• Post-traumatic arthritis: Arthritis developing after a significant knee injury, including fractures involving the joint surface, severe ligament disruptions, or meniscal injuries that alter joint mechanics over time.

The presence of degenerative changes on X-ray does not, by itself, indicate that replacement is needed. Many people have early signs of wear and tear on imaging without symptoms that warrant surgical intervention. The clinical decision weighs imaging findings alongside the pattern and severity of symptoms, functional limitation, and the patient’s response to prior treatment.

What Does Total Knee Replacement Involve?

The procedure resurfaces the damaged ends of the three bones that form the knee joint: the femur (thigh bone), tibia (shin bone), and patella (kneecap). Worn cartilage and a thin layer of underlying bone are removed with precision instruments, and shaped metal and plastic components are fixed in their place. The result is a smooth, pain-free articulating surface that replicates the function of the original joint.

The Components

A total knee replacement consists of three main components. The femoral component is a curved metal piece that caps the end of the thigh bone. The tibial component is a flat metal platform fixed to the top of the shin bone, with a plastic insert (polyethylene) that provides the smooth articulating surface. The patellar component resurfaces the underside of the kneecap if required.

Components are manufactured to precise tolerances and available in multiple sizes to match individual anatomy. Most are fixed with bone cement, though cementless fixation techniques are used in selected cases.

Anaesthesia and Duration

Total knee replacement is performed under spinal or general anaesthesia, with the choice determined by the patient’s health, preferences, and anaesthetic assessment. The surgical procedure itself typically takes 60 to 90 minutes. Most patients are admitted on the day of surgery and remain in the hospital for two to three days, though this varies depending on individual recovery trajectories. 

Clinical Note: Partial vs Total Replacement

Not all patients with knee arthritis require total knee replacement. When arthritis is confined to a single compartment of the knee, unicompartmental (partial) knee replacement may be appropriate. 

This preserves more of the natural joint and typically allows faster recovery, but is only suitable where the other compartments and ligaments are intact. Assessment will determine which procedure is most appropriate for each patient’s anatomy and disease pattern.

Preparing for Surgery

Preparation for total knee replacement begins well before the admission date. A structured pre-operative programme addresses the physical, logistical, and psychological aspects of preparation and has a measurable impact on recovery outcomes.

Key elements of pre-operative preparation include:

Prehabilitation: Strengthening the muscles around the knee, particularly the quadriceps, before surgery. Patients who enter surgery with better muscle function recover more quickly and achieve better functional outcomes. Even a modest improvement in strength in the weeks before the procedure makes a meaningful difference.

Weight management: Excess body weight increases both surgical risk and the load placed on the replacement components during recovery. Where weight reduction is achievable before surgery, it improves outcomes.

Medical optimisation: Managing blood pressure, blood sugar, and other medical conditions to reduce anaesthetic and surgical risk. This is coordinated with the patient’s GP and relevant specialists.

Home preparation: Arranging appropriate support at home, removing trip hazards, and ensuring bathroom and sleeping arrangements are safe for the immediate post-operative period.

Recovery: What to Expect at Each Stage

Recovery from total knee replacement follows a predictable sequence, though the pace varies between patients. The goals at each stage are consistent: manage pain appropriately, restore movement progressively, and rebuild the muscle strength on which long-term function depends.

Days 1 to 3: Hospital

Most patients begin standing and taking their first steps with physiotherapy support on the day of surgery or the day after. Early mobilisation is deliberate and evidence-based: movement reduces the risk of blood clots, limits stiffness, and begins restoring function. Pain is managed with a multimodal approach combining regional anaesthesia, anti-inflammatory medications, and, where necessary, short-term opioid analgesics.

The goal of pain management is to achieve sufficient comfort to participate in rehabilitation, not a complete absence of pain. Understanding the role of different analgesic strategies in the days following joint replacement helps patients engage more effectively in the recovery process.

Patients often feel well on the day of surgery, but as swelling in the replaced joint increases, reduced range of motion and pain become common.  This is fairly predictable. This period involves finding the right balance for rest and physiotherapy.  Dr Cohen recommends aiming for 750-1000 steps per day in week 1 and increasing by 500 steps each week. Too much exercise will increase pain and prolong swelling.  Dr Cohen also emphasises the rule of 20 every 2 hours: 20 minutes of ice, 20 minutes of elevation, and 20 minutes of exercise, even if it’s just gentle ankle pumps or knee range-of-motion exercises. Pain is at its peak between days 2 and 14, but rest assured, it settles with time. 

Weeks 1 to 6: Early Recovery at Home

The first six weeks focus on restoring the basic range of motion, managing swelling, and beginning muscle reactivation. Physiotherapy is central to this phase, with exercises targeting knee flexion and extension, quadriceps activation, and progressive weight-bearing. Swelling is normal and may persist for several weeks; it is managed with elevation, ice, and compression.

Most patients are walking independently with a frame or crutches within days of discharge, transitioning to a walking stick and then to unassisted walking as strength and confidence improve. Driving is typically possible from six weeks, subject to surgical and anaesthetic clearance.

Weeks 6 to 12: Building Strength

This phase marks the transition from basic mobility recovery to active rehabilitation. The pain-weakness cycle that develops in arthritic joints, where pain reduces activity, activity reduction weakens muscles, and weakened muscles worsen joint loading, does not resolve automatically after surgery. Progressive strengthening of the quadriceps, hip abductors, and calf muscles is essential to achieving good long-term outcomes and reducing the risk of complications.

By 12 weeks, most patients have achieved functional independence for daily activities including walking, stairs, and light domestic tasks. A return to low-impact recreational activities such as swimming and cycling is typically possible during this period.

Three to Twelve Months: Full Recovery

Full recovery from a total knee replacement takes 6 to 12 months, and up to 2 years in some patients. The replacement joint continues to settle and soften during this period, and patients often notice ongoing gradual improvements in comfort and range of motion well beyond the three-month mark. Stiffness that persists beyond six months should be discussed with the surgical team.

Activities compatible with total knee replacement include walking, swimming, cycling, golf, and low-impact recreational sports. High-impact activities, including running and contact sports, are generally discouraged as they accelerate wear of the replacement components.

Recovery Framework

Recovery from total knee replacement follows the same principle as conservative joint management: 

(1) Manage pain to allow participation in rehabilitation. 

(2) Control swelling and restore range of motion. 

(3) Build progressive strength to restore function and protect the replacement. 

Each phase builds on the last. Skipping or rushing the strengthening phase is the most common reason for suboptimal long-term outcomes.

How Long Does a Total Knee Replacement Last?

Contemporary knee replacement components have excellent longevity. Published registry data consistently show 15-year survivorship rates of 90 to 95%, indicating that the vast majority of patients do not require revision surgery during that period. Factors that influence longevity include patient activity level, body weight, and the quality of the surrounding musculature.

Younger and more active patients may eventually require revision surgery as the replacement wears over decades of use. Advances in bearing surface technology and surgical technique continue to improve long-term outcomes.

When to Seek Assessment

Total knee replacement is not a decision that needs to be made urgently. For most patients, there is time to appropriately trial conservative management, to fully understand the procedure, and to prepare well. The right time to seek assessment is when knee pain consistently limits daily activities, when conservative management provides inadequate relief, or when a GP or physiotherapist has recommended a specialist review.

Early specialist assessment does not commit a patient to surgery. It establishes a clear diagnosis, clarifies the stage of disease, and opens a conversation about all management options, conservative and surgical, and the appropriate timing of each.

Dr Dan Cohen provides orthopaedic assessment and total knee replacement surgery for patients across Sydney, consulting at Bondi Junction and Kogarah. Assessment establishes a clear diagnosis, interprets imaging in the context of the full clinical picture, and develops a management plan appropriate to the stage and severity of each patient’s condition. Get in touch to make a booking.