Total Knee Arthroplasty (TKA)

• Document implant manufacturer, model, and sizes (femoral size, tibial tray size, poly insert thickness, patellar component size if resurfaced) in the operative note. FDA UDI documentation is mandatory — record UDI for each component. A note that states 'TKA performed' without implant specifications is inadequate for registry, FDA adverse event reporting, and future revision planning.
• Document tourniquet time and pressure. Use limb occlusion pressure-based inflation (SBP + 100–150 mmHg, typically 200–250 mmHg) rather than a fixed high pressure (275 mmHg) — high fixed pressures are associated with quadriceps injury and wound complications per current evidence. Document total tourniquet time; times exceeding 90 minutes are associated with increased wound complications. Document tourniquet deflation and hemostasis confirmation before closure.
• Document posterior tibial slope. Tibial slope (typically 3–7°, design-specific) affects flexion kinematics and PCL tension. Failure to set appropriate slope is a source of stiffness or instability. Document: 'proximal tibial resection performed with [X]° posterior tibial slope.'
• Document intraoperative gap balance and soft tissue releases on trial components. Record flexion gap, extension gap, varus/valgus stability at 0° and 90°, and any releases performed (medial soft tissue release, lateral release, PCL release). This is the surgeon's intraoperative quality check and justifies final implant selection. It also provides documentation if stiffness or instability develops postoperatively.
• Document failed conservative treatment for medical necessity. Payer audits for TKA commonly focus on: duration of conservative treatment (minimum 3 months typically required), specific interventions (physical therapy, NSAIDs, corticosteroid injections, viscosupplementation), radiographic evidence of joint space loss (Kellgren-Lawrence grade 3 or 4), and functional limitations. 'Failed conservative management' without specific detail is insufficient for many payer LCD requirements.

• 27447 (arthroplasty, knee, condyle and plateau; medial AND lateral compartments with or without patella resurfacing — total knee arthroplasty; 19.11 wRVU, 90-day global) covers all primary TKA designs — cruciate-retaining (CR), posterior-stabilized (PS), and constrained condylar (CCK). Implant design does not change the code. Document the specific design rationale (PCL retained vs. sacrificed, degree of constraint) and implant specifications.
• Revision TKA uses 27486 or 27487 — these are standalone primary codes billed INSTEAD of 27447, not in addition to it. Never bill 27447 and a revision code together. 27486 (revision of total knee arthroplasty, with or without allograft; 1 component; 20.59 wRVU, 90-day global) for single-component revision. 27487 (femoral and entire tibial component; 26.43 wRVU, 90-day global) for both femoral and tibial revision. 27488 (removal of prosthesis including total knee prosthesis, methylmethacrylate, with or without insertion of spacer; 17.16 wRVU, 90-day global) for first-stage explant in two-stage revision for periprosthetic joint infection.
• Unicompartmental knee arthroplasty uses 27446 (arthroplasty, knee, condyle and plateau; medial OR lateral compartment; 16.70 wRVU, 90-day global), not 27447. Both medial and lateral UKA are 27446 — the medial/lateral distinction does not change the code. Document unicompartmental vs. total to ensure correct code selection.
• Bilateral TKA at the same session: 27447 carries bilateral procedure indicator 1 under CMS. Medicare pays 27447-50 (bilateral modifier) at 150% of the single-procedure fee. Some MACs prefer 27447-RT and 27447-LT on two separate claim lines (first at 100%, second at 50%). Verify payer-specific bilateral modifier conventions. Staged bilateral within 90 days of the first TKA global period: bill the second knee with modifier -79 (unrelated procedure during global period) if the second TKA is truly independent, or -58 (staged) if planned as staged at time of first surgery.
• NCCI bundling: arthroscopy of the same knee on the same day (29870-29881), synovectomy (27334-27335), debridement, and lavage are bundled into 27447 and cannot be unbundled with modifier -59. Manipulation under anesthesia for postoperative stiffness (27570, 1.75 wRVU, 10-day global) within the 90-day global requires modifier -78. Modifier -78 does not reset the global period — the remaining global days of the primary TKA continue.
• Implant documentation: FDA UDI tracking is mandatory for knee prostheses (Class III devices). Record manufacturer, model, lot number, component sizes, and UDI for femoral component, tibial baseplate, polyethylene insert, and patellar component. AJRR reporting is voluntary, not a state mandate. Document implant details in the operative note — 'TKA performed' without specifications is inadequate for registry, FDA adverse event reporting, and future revision planning.

General coding reference. Verify with your institution’s billing department before submitting claims.

ⓘ General Billing Tips →