CPT code 27599: Unlisted procedure, femur or knee2026 Medicare rate & RVUs in California

CMS doesn’t publish an office rate for 27599 in California.

Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.

What 27599 covers

CPT 27599 is for an operation involving the femur or knee when no listed CPT code describes the procedure performed. An orthopedic surgeon or other physician reports it when the available codes do not describe the operation’s method and extent. The operative report should identify the anatomic site, technique, and extent and explain why a listed code does not fit. A comparable listed procedure can help the Medicare contractor evaluate the claim.

Medicare assigns status C: CMS publishes no national payment, and the Medicare Administrative Contractor sets payment for each claim. The contractor also sets the global period. For procedures performed in the same session, the highest-valued procedure is paid in full and the other procedures are paid at 50%. For a bilateral procedure reported with modifier 50, Medicare pays 150%.

This summary was written with AI assistance from CMS physician fee schedule data and checked against the CMS billing rules shown here. Rates on this page come directly from CMS files.

Where 27599 pays more and less in California

The same RVUs, adjusted for each area’s costs. Open a locality for its calculation, history and nearby areas.

29 of 29 payment localities

How the 27599 rate is calculated

Each of 27599’s three RVUs is multiplied by a geographic index (GPCI) for the payment locality, added up, and multiplied by the conversion factor. Drag the indexes or enter a ZIP to see what moves the rate.

Payment rules and modifiers for 27599

The CMS indicators that decide how 27599 is paid alongside other services.

What modifiers do to the payment

When to use modifier 50

27599 compared with similar codes

How to choose

27570Knee manipulationUnder anesthesia

This code describes manipulation of the knee under anesthesia. Use 27599 only when the operation performed is not represented by a listed procedure code.

27580Knee fusionArthrodesis, any technique

This code describes fusion of the knee. Report it when knee fusion is the procedure performed rather than using 27599.

27590Thigh amputationThrough femur, any level

This code describes thigh-level amputation. Report it for that defined operation rather than using 27599.

Where these rates come from

FeeBase calculates base physician payments from CMS work, practice-expense and malpractice RVUs, adjusted by each locality’s geographic indexes and the conversion factor. Services without a published rate are labeled, never given a made-up amount. Amounts are Medicare allowed amounts before claim adjustments: not a patient’s bill or a commercial rate.

CMS RVU26D · effective Oct 1, 2026 through the day before Jan 1, 2027

Open CMS sourceHow we calculate rates