Total Knee Replacement

After total knee replacement, nurses fight two battles at once — preventing deadly clots AND winning back flexion before scar tissue locks the joint. ROM recovery is the unique nursing priority that differentiates TKA postop care.

Total knee arthroplasty (TKA) replaces damaged femoral and tibial joint surfaces, most commonly for severe osteoarthritis. Postoperatively, the priority unique to TKA is aggressive early range-of-motion (ROM) recovery. A continuous passive motion (CPM) machine may be used (practice varies by surgeon and facility; NCLEX may still test CPM knowledge), beginning at 0–30 degrees of flexion and advancing as tolerated. The discharge ROM goal is generally 90 degrees of flexion — enough to climb stairs and rise from a chair. Unlike total hip replacement, there are no posterior hip precautions. The operative leg is elevated on pillows with the knee in extension (not a pillow under the knee, which promotes flexion contracture). Patients are typically weight-bearing as tolerated (WBAT) with a walker or crutches; ambulation begins day of surgery or postop day one. Neurovascular checks — circulation, sensation, movement distal to the surgical site — are performed frequently. DVT prophylaxis is critical: sequential compression devices, anticoagulants (commonly enoxaparin for 10–14 days or warfarin), and early ambulation. Ice or cryotherapy is applied to reduce swelling. Assess drain output if present; monitor for signs of infection. Pain management must be adequate to allow participation in physical therapy — uncontrolled pain is the top barrier to ROM goals.

Key Distinctions

TKA vs THR positioning: TKA elevates the leg in extension on pillows; THR uses an abduction pillow and avoids flexion past 90 degrees. A pillow under the knee promotes flexion contracture and is contraindicated — pillow goes under the ankle. CPM is classically tested in the context of TKA, not THR. TKA neurovascular checks vs compartment syndrome: both involve CMS assessment, but compartment syndrome presents with pain out of proportion to injury and demands emergent intervention, whereas routine TKA CMS checks monitor for expected postop changes.

Clinical Pearl

Pillow under the ankle, never under the knee. That one positioning error can cost the patient their ability to fully straighten the leg permanently.