Total Knee Replacement: What to Expect During Surgery
Total knee replacement (TKR) is one of the most common and successful orthopedic procedures performed today. Learn what the surgery involves, implant types, anesthesia options, risks, and how to prepare.
What Is Total Knee Replacement?
Total knee arthroplasty (TKA) — commonly called total knee replacement — is a surgical procedure in which the damaged surfaces of the knee joint are replaced with metal and plastic prosthetic components. All three compartments (medial, lateral, and patellofemoral) are resurfaced.
TKA is one of the most commonly performed orthopedic surgeries in the United States, with over 700,000 procedures annually. Patient satisfaction rates are approximately 85–90%, with excellent pain relief in the vast majority.
Implant Components
Femoral component: Metal (cobalt-chromium alloy) cap that replaces the curved distal end of the femur
Tibial component: Metal tray with a plastic (ultra-high molecular weight polyethylene) insert that acts as the new joint surface
Patellar component: Plastic button (sometimes the natural patella surface is retained)
Modern implants last 15–20 years in most patients.
Who Is a Candidate?
TKA is recommended for patients with:
- End-stage knee osteoarthritis (Grade 4, bone-on-bone)
- Rheumatoid or inflammatory arthritis of the knee
- Post-traumatic arthritis
- Severe, disabling knee pain unresponsive to extensive conservative treatment
- Significant functional limitations (difficulty walking short distances, climbing stairs, getting out of chairs)
Pre-Operative Preparation
- Medical clearance (cardiac, pulmonary as needed)
- Labs, EKG, urine analysis
- Prehabilitation exercises (4–6 weeks of quad and hip strengthening before surgery dramatically improves post-op outcomes)
- Dental clearance (treat infections before implanting a prosthesis)
- Home modifications: raised toilet seat, shower chair, grab bars, remove trip hazards
- Arrange 4–6 weeks of home assistance
- Stop smoking — nicotine impairs healing and increases infection risk
Day of Surgery
Anesthesia
Spinal anesthesia (regional block numbing from the waist down) is the preferred anesthetic for TKA — associated with less blood loss, lower complication rates, and less post-operative nausea than general anesthesia. Sedation is given for comfort. Nerve blocks (adductor canal block, periarticular injections) are added for post-operative pain control.
General anesthesia is available for patients with contraindications to spinal.
Surgical Steps (60–90 minutes)
- Positioned supine (on back); tourniquet on thigh (inflated during key portions)
- Midline incision over the kneecap (8–10 inches)
- Medial parapatellar arthrotomy (opening the joint)
- Femoral bone cuts made using alignment guides or computer/robotic assistance
- Tibial bone cut made perpendicular to the mechanical axis
- Patellar surface prepared and resurfaced (or retained)
- Trial implants tested — alignment, stability, range of motion, soft tissue balance
- Final implants cemented into place (most cases; some use press-fit/biological fixation)
- Wound irrigated and closed in layers
- Drain placed (typically removed day after surgery)
- Compressive dressing and knee immobilizer or brace applied
Robotic-Assisted TKA
Computer navigation and robotic-arm systems (Mako Robotic-Arm, NAVIO) are increasingly used to improve precision of bone cuts and implant positioning. Some evidence suggests improved accuracy; long-term outcome differences remain under study.
Hospital Stay
Most TKA patients stay 1–2 nights (some centers do same-day with enhanced recovery protocols). Physical therapy begins on the day of surgery.
Risks and Complications
- Deep vein thrombosis (DVT) / Pulmonary embolism (PE): Most feared complication; anticoagulation is mandatory
- Periprosthetic joint infection (PJI): Rate <1–2%; devastating if it occurs; may require revision
- Implant loosening or wear: Long-term complication; most implants last 15–20 years
- Stiffness (arthrofibrosis): Failure to achieve adequate range of motion; prevented by early aggressive PT
- Persistent pain: 15–20% of TKA patients have some persistent pain — the most common cause of dissatisfaction
- Nerve or vascular injury: Rare
- Patella complications: Maltracking, fracture, component issues
What to Bring
- Button-down or zip-front top; elastic waist pants
- Slip-on shoes — non-slip soles
- All assistive equipment already set up at home
- Comfort items for 1–2 night stay
- Phone, charger, entertainment