Total Knee Arthroplasty (TKA)

Total Knee Arthroplasty (TKA)

Prepared by Dr. Kayahan KARAYTUG

Overview

• Total knee arthroplasty (TKA) is a reconstructive procedure that replaces the articular surfaces of the femur, tibia, and (optionally) patella with prosthetic components to relieve pain and restore function.
• Conventional TKA relies on standard mechanical or instrumented alignment guides, surgeon judgment, and intraoperative soft-tissue balancing.

Indications

• End-stage, symptomatic knee osteoarthritis with severe pain and functional limitation despite adequate non-operative treatment.
• Inflammatory arthropathy with joint destruction and disability.
• Post-traumatic arthritis with loss of function and persistent pain.
• Selected deformity/instability cases where reconstruction is feasible.

Contraindications

Absolute

• Active joint or systemic infection.
• Severe medical comorbidity precluding anesthesia or safe surgery.
• Non-reconstructable extensor mechanism failure (relative to indication and reconstruction options).

Relative / require optimization

• Poorly controlled diabetes, severe obesity, malnutrition, active smoking.
• Severe peripheral vascular disease or neuropathic arthropathy.
• Unrealistic expectations or inability to participate in rehabilitation.

Preoperative assessment

• History: pain pattern, instability, prior surgery/injection history, functional goals.
• Exam: alignment, ROM, flexion contracture, ligament stability, gait, neurovascular status.
• Imaging: standing AP/lateral/skyline patella; long-leg alignment views when deformity or planning requires.
• Optimization: infection risk (skin, dental as indicated), glycemic control, anemia, BMI, smoking cessation, VTE risk planning.

Implant concepts and design choices

Bearing and constraint

• Fixed-bearing is most commonly used; mobile-bearing is selective and technique-dependent.
• CR (cruciate-retaining): preserves PCL when functional; aims for more physiologic rollback.
• PS (posterior-stabilized): substitutes PCL with cam-post mechanism; useful when PCL is insufficient.
• Constrained condylar or hinge designs are reserved for severe instability, major bone loss, or revision scenarios.

Fixation

• Cemented fixation remains the standard for most primary TKAs.
• Cementless fixation is used selectively (often younger patients with good bone stock) depending on implant system and surgeon preference.

Key surgical steps (high-level)

• Approach: most commonly medial parapatellar; exposure tailored to anatomy and deformity.
• Bone cuts: distal femur and proximal tibia resection using mechanical/instrument guides; femoral rotation set by anatomic and balancing principles.
• Soft-tissue balancing: achieve rectangular flexion and extension gaps; address varus/valgus contractures.
• Trialing: confirm alignment, stability through ROM, patellar tracking, and component sizing.
• Cementation or press-fit per plan; layered closure; consider topical TXA and multimodal analgesia per ERAS pathway.

Postoperative rehabilitation (typical milestones)

Day 0–1

• Weight bearing as tolerated (unless specific constraints).
• Quadriceps sets, straight-leg raise (as able), ankle pumps; ice/compression.

Week 1–2

• ROM target ~0–90°; walker → cane transition as gait control improves.
• Focus on swelling control and quadriceps activation.

Week 3–6

• ROM target ~110–120°; stair training, balance and closed-chain strengthening.

Week 6–12

• Independence in basic ADLs; structured walking program and progressive strengthening.

After 3 months

• Allowed: walking, swimming, cycling; avoid running/jumping and contact sports (general guidance).

Complications to anticipate

• Infection (superficial/deep), stiffness/arthrofibrosis, VTE, wound issues.
• Instability, aseptic loosening, periprosthetic fracture, patellofemoral complications, neurovascular injury (rare).
• Persistent pain—evaluate for infection, loosening, instability, malalignment, CRPS, or referred pain.

Follow-up and outcome assessment

• Early visits focus on wound healing, ROM progression, pain control, and gait recovery.
• Later follow-up evaluates function, radiographs for fixation/osteolysis, and patient-reported outcome measures.

References

1. American Academy of Orthopaedic Surgeons (AAOS). Surgical Management of Osteoarthritis of the Knee: Evidence-Based Clinical Practice Guideline. Adapted by AAOS Board of Directors; December 2, 2022.
2. Insall & Scott Surgery of the Knee. Total Knee Arthroplasty sections (latest edition).
3. Campbell’s Operative Orthopaedics. Total Knee Arthroplasty chapter (latest edition).
4. Parvizi J, Gehrke T (eds). Proceedings/consensus on periprosthetic joint infection (for infection work-up and management principles).
5. Kurtz SM, Ong KL, Lau E, et al. Projections/epidemiology and outcomes related to total knee arthroplasty (review/registry-based literature).
6. Katz JN, Arant KR, Loeser RF. Diagnosis and treatment of hip and knee osteoarthritis: a review. JAMA. 2021;325(6):568–578.
7. Enhanced Recovery After Surgery (ERAS) Society. Consensus guidelines for perioperative care in total hip/knee arthroplasty (latest update).