Total Knee Replacement
Complete guide to total knee replacement — who is a candidate, implant types, surgical approaches, robotic surgery, cost comparison, and recovery. Plan with Gaf Healthcare.
Estimated cost: $3,500 – $5,500 · Average stay: 5–7 days
Total knee replacement (TKR) — total knee arthroplasty (TKA) — is the most commonly performed major orthopaedic procedure in the world, with over 700,000 procedures annually in the United States and approximately 1.5 million globally each year. It replaces the damaged bone and cartilage surfaces of the knee joint with precision-engineered metal and plastic components, eliminating the bone-on-bone friction that causes the severe, debilitating pain of end-stage knee arthritis.
When non-surgical treatments — physiotherapy, weight management, anti-inflammatory medications, intra-articular injections — no longer provide adequate relief and quality of life is significantly impaired, total knee replacement offers a highly reliable solution. Functional outcomes are excellent: over 90% of patients report significant satisfaction with pain relief and functional improvement, and 95% of knee replacements are still functioning well at 10 years; over 80% at 25 years.
The prosthetic components — available from manufacturers including Zimmer Biomet, Stryker, Johnson & Johnson DePuy Synthes, Smith+Nephew, and others — are precision-engineered devices designed to replicate normal knee kinematics while eliminating pain from bone-on-bone contact. Advanced implant designs now include highly cross-linked polyethylene for superior wear resistance, oxidised zirconium for metal-sensitive patients, and robotic-assisted implant positioning systems that customise component placement with sub-millimetre accuracy.
Gaf Healthcare partners with high-volume orthopaedic surgery programs where knee replacement volumes exceed 500 procedures annually — a level consistently associated with superior outcomes and lower complication rates in international joint registry data.
What Happens in a Knee Replacement? Anatomy and Implant Design
The knee is anatomically divided into three compartments: medial (inner side), lateral (outer side), and patellofemoral (front, between kneecap and femur). Osteoarthritis most commonly begins in the medial compartment; isolated medial compartment disease can be treated by unicompartmental (partial) knee replacement. Tricompartmental arthritis requires total knee replacement.
The TKR implant system consists of: the femoral component (a precision-curved metal shell resurfacing the end of the femur), the tibial tray (a flat metal plate anchored to the top of the tibia), and the tibial insert (a high-density polyethylene spacer that sits between the metal components, providing a smooth articulating surface).
Implant fixation is achieved by cemented or cementless methods. Cemented fixation — using polymethylmethacrylate bone cement — provides immediate strong fixation and is the most reliable method for all age groups. Cementless fixation — using highly porous metal surfaces allowing bone ingrowth — is used in younger patients where long-term biological fixation is critical.
Posterior-stabilised (PS) versus cruciate-retaining (CR) implant design reflects whether the posterior cruciate ligament (PCL) is retained or sacrificed. Most contemporary TKA uses posterior-stabilised designs with the PCL removed.
Who Is a Candidate for Total Knee Replacement?
TKR is indicated for patients with severe knee arthritis causing significant functional impairment and pain not adequately controlled by comprehensive non-surgical management. The decision is guided by symptom severity (not radiological findings alone), functional limitation, and overall health status.
Clinical candidacy criteria: severe knee pain limiting walking distance, significantly disrupting sleep, and impairing daily activities; significant quality-of-life reduction from knee arthritis; failure of at least 3–6 months of conservative management (physiotherapy, weight management, analgesics, injections); and radiological confirmation of severe joint space loss on weight-bearing X-rays.
The optimal surgical candidate has BMI below 40 (higher BMI significantly increases complication risk), no active skin infection over the knee, no severe systemic comorbidities that cannot be optimised, and realistic expectations about recovery timeline (6–12 months for full functional recovery).
Patients NOT appropriate for TKR include: those with mild-to-moderate arthritis still responding to conservative measures; patients with primary anterior knee pain without objective arthritis; BMI above 40–45; active local or systemic infection; and those with severe vascular disease in the operated limb. Age alone is not a criterion — physiological fitness and comorbidity burden matter more than chronological age.
The Knee Replacement Operation: Surgical Technique
Total knee replacement is performed under general or spinal anaesthesia, typically taking 60–90 minutes. A midline incision (10–15 cm for standard; 8–10 cm for minimally invasive) is made over the anterior knee; the joint is exposed by reflecting the patella medially.
The surgeon systematically removes precise amounts of bone from the distal femur, proximal tibia, and posterior femur using cutting jigs aligned to mechanical axis landmarks. The goal is to resurface the joint surfaces in exact thicknesses accommodating the chosen implant components and restoring the native mechanical alignment of the leg.
Trial components are inserted and the knee is assessed through full range of motion: stability, gap balance (equal flexion and extension gaps), patellar tracking, and range of motion are carefully evaluated before final implant cementation.
Robotic-assisted systems (Mako, VELYS, CORI) use pre-operative CT planning and intraoperative haptic feedback to guide bone resection within ±1 mm of the planned cuts — providing unprecedented implant positioning accuracy. After cementation and component assembly, the wound is closed in layers.
Procedure Steps
- Pre-operative optimisation: weight-bearing X-rays (standing AP, lateral, skyline), anaesthesia review, blood saving strategy planning (tranexamic acid protocol).
- Anaesthesia: spinal (preferred for blood loss reduction) or general; tourniquet applied to thigh.
- Surgical exposure: anterior incision; medial parapatellar arthrotomy; patella everted.
- Bone resection using calibrated cutting jigs; alignment verified by mechanical axis checks or robotic navigation.
- Trial components placed; knee balanced through ROM; flexion-extension gaps assessed; component sizes confirmed.
- Definitive implant cementation with antibiotic-impregnated bone cement.
- Closure: capsular and wound closure; dressings applied.
- Immediate rehabilitation: physiotherapy on day 0–1; weight-bearing walking with zimmer frame.
Types of Knee Replacement Surgery
Total Knee Replacement (Conventional)
Replacement of all three knee compartments through a standard anterior incision. Uses established cutting jig systems with or without computer navigation. Reliable, proven outcomes with 20-year implant survivorship above 80%. Suitable for all patients with tricompartmental or bicompartmental knee arthritis.
Cost: $7,000 – $16,000
Robotic-Assisted TKR (Mako / VELYS / CORI)
Pre-operative CT-based planning and intraoperative haptic robotic arm guidance. Enables bone resection within ±1 mm of the surgical plan. Provides more precise implant positioning and balancing than conventional techniques, with reduced outlier rates. Associated with improved early functional outcomes at experienced centres.
Cost: $11,000 – $22,000
Unicompartmental Knee Replacement (Partial Knee)
Replacement of only the medially or laterally diseased compartment in patients with unicompartmental arthritis. Smaller incision, faster recovery, and preserved normal knee kinematics compared to TKA. Requires intact ACL and normal opposite compartment. Oxford, Zimmer Biomet, and Stryker partial knee systems are established platforms.
Cost: $6,000 – $13,000
Bilateral Simultaneous TKR
Both knees replaced in a single anaesthetic session — appropriate for selected patients with bilateral severe tricompartmental arthritis. Reduces total hospitalisation and rehabilitation period. Carries higher early complication risk (blood loss, cardiac demands) and requires careful patient selection — generally limited to patients under 70 with excellent cardiopulmonary reserve.
Cost: $13,000 – $26,000
Cost Comparison Worldwide
Country — Range — Savings
--- — --- — ---
United States — $30,000 – $65,000 — Baseline
United Kingdom — $12,000 – $22,000 — ~65% vs. USA
Germany — $10,000 – $20,000 — ~68% vs. USA
India — $5,000 – $10,000 — Up to 85% vs. USA
UAE — $12,000 – $22,000 — ~65% vs. USA
Knee replacement costs in the US include the implant hardware, operating room facility fee, surgeon fee, anaesthesia, and inpatient hospital stay — totalling $30,000–$65,000. At internationally accredited orthopaedic programs, the same generation of knee implants from the same global manufacturers are used at dramatically lower total cost driven by lower facility and labour overhead. Gaf Healthcare provides transparent itemised estimates specifying implant manufacturer, fixation method, and hospital stay.
Recovery & Follow-up
TKR recovery follows an intensive trajectory: walking with a zimmer frame on day one, physiotherapy twice daily in hospital (typically 3–5 days), and progressive rehabilitation over 6–12 weeks after discharge. The rehabilitation milestones are: walking with a zimmer frame by day 1; walking with crutches by week 2; discontinuing walking aids by week 4–6; driving at 6 weeks; returning to desk work at 4–6 weeks; full functional return at 6–12 months. Range of motion — bending the knee beyond 90 degrees — requires consistent daily exercise.
Recovery Tips
- Walk and do physiotherapy exercises every day — passive recovery leads to poor range of motion.
- Elevate the operated leg above heart level when resting for the first 2–3 weeks.
- Ice the knee for 20 minutes after each exercise session.
- Practice active flexion exercises: target 90° by 2 weeks, 120° by 6 weeks.
- Take anticoagulants (rivaroxaban or LMWH) for the full prescribed duration.
- Report increasing redness, warmth, swelling, or wound discharge immediately.
- Continue compression stockings until fully mobile.
- Plan your home: raised toilet seat, bath board, removing trip hazards.
Risks & Complications
TKR is a major joint replacement surgery with defined complication rates. Deep vein thrombosis is the most common complication (dramatically reduced with thromboprophylaxis). Periprosthetic joint infection (PJI) — the most catastrophic complication — occurs in approximately 1–2% of primary TKRs and often requires staged revision. Aseptic loosening is the most common cause of revision at 15–20 years. Persistent pain and stiffness affect approximately 10–15% of patients. Operative mortality at high-volume centres is below 0.3%.
Why GAF Healthcare
TKR outcomes are strongly correlated with surgical volume — hospitals performing 500+ knee replacements annually have lower infection rates, shorter stays, and better functional outcomes. Gaf Healthcare partners exclusively with high-volume knee arthroplasty programs, verifies annual case volumes, and arranges comprehensive post-operative rehabilitation coordination with your home physiotherapy team.
Frequently Asked Questions
How long does a knee replacement last?
National joint registries from Australia, the UK, and Sweden show 95% of knee replacements functioning at 10 years and over 80% at 25 years. Modern highly cross-linked polyethylene inserts have dramatically reduced wear rates. Younger, more active patients have higher revision rates due to greater implant demand.
Is robotic knee replacement better than conventional surgery?
Robotic-assisted TKR provides superior implant positioning precision and more consistent gap balancing than conventional techniques. Multiple studies show lower rates of implant malalignment outliers with robotic assistance. Whether this translates into meaningfully better long-term survivorship compared to conventional surgery by experienced high-volume surgeons is being established by long-term follow-up data.
What activities can I do after knee replacement?
Walking, swimming, cycling, golf, light hiking, doubles tennis, and yoga are all well supported. High-impact activities — running, contact sports — are advised against because they increase implant wear. Most patients experience dramatic improvement in functional capacity, walking distances and climbing stairs that arthritis previously prevented.
How long before I can fly home?
We recommend 7–10 days near the surgical centre. This allows wound inspection, suture/staple removal at day 7–10, and confirmation of adequate range of motion progress. Long-haul air travel before 10–14 days post-TKR carries increased DVT risk; we recommend prophylactic anticoagulation before long flights and compression stockings throughout.
Is partial knee replacement a good option?
For patients with arthritis strictly confined to one compartment with an intact ACL, unicompartmental knee replacement offers smaller incision, faster recovery, preserved natural kinematics, and lower peri-operative risk. If disease later progresses, conversion to TKA is straightforward. At centres with high partial knee volume and careful selection, outcomes are excellent with faster functional recovery.