CPT code 01360: Anesthesia for open distal femur procedures

Key takeaways

CPT code 01360 covers anesthesia for all open procedures on the lower one-third of the femur, and it carries 5.0 base units.

It is the open counterpart to 01340, which covers closed procedures on the same segment of femur.

01360 is not a knee-joint code and not a catch-all, so knee surgery belongs under 01380, 01400, or 01402.

Reimbursement is (base units + time units) x conversion factor, and the 2026 national anesthesia conversion factor is $20.4976.

Practice management software like Pabau helps billing teams track anesthesia claims from submission through payment, so denials surface early.

CPT code 01360 covers anesthesia for open procedures on the lower one-third of the femur. In practice that means an open reduction and internal fixation (ORIF) of a distal femur fracture, or an open repair just above the knee.

The code sits inside the CPT manual’s Knee and Popliteal Area range, and that is where the confusion starts. The range name is regional, but the descriptor for 01360 is not. It covers the distal femur only, and it is not a not-otherwise-specified code.

This guide covers the official descriptor, the 5.0 base units, and the surgical procedures that map to it. It also covers modifiers, ICD-10 pairings, the 2026 fee schedule, and the code-selection errors that drive denials.

CPT code 01360: Definition and anatomical scope

CPT code 01360 has the following official American Medical Association (AMA) descriptor: Anesthesia for all open procedures on lower one-third of femur.

Two words in that descriptor do all the work. “Open” means the surgeon made an incision at the fracture or bone segment. “Lower one-third of femur” means the distal thigh bone, just above the knee joint.

That region is the supracondylar, transcondylar, and distal shaft territory. Once the surgery moves into the knee joint itself, or up into the upper two-thirds of the femur, a different anesthesia code applies.

A common misreading turns 01360 into a broad “upper leg and knee” catch-all. It isn’t. The not-otherwise-specified code in this part of the manual is 01400, which covers open or surgical arthroscopic procedures on the knee joint.

01360 vs 01340: Open versus closed on the same bone

01360 and 01340 describe the same anatomy. The only difference is the surgical approach, and it is worth 1.0 base unit.

• 01340 – closed procedures on the lower one-third of the femur, 4.0 base units. Closed reduction, manipulation, or traction, with no incision at the fracture.
• 01360 – open procedures on the lower one-third of the femur, 5.0 base units. The surgeon opens the site to reduce, plate, nail, graft, or realign the bone.

Read the operative report, not the diagnosis, to tell them apart. A distal femur fracture can be treated either way, so the diagnosis code will not decide this for you.

If the report describes an incision, an implant, hardware, or a bone graft, the case is 01360. If the surgeon reduced the fracture through the skin and immobilized it, the case is 01340.

Procedures covered under 01360

The surgeon bills the procedure code and the anesthesia provider bills 01360 on a separate claim. The two lines don’t conflict. The surgical codes below are the ones that most often sit behind an 01360 claim.

• Open treatment of a supracondylar or transcondylar femoral fracture without intercondylar extension – CPT 27511, the most frequent pairing with 01360
• Open treatment of a supracondylar or transcondylar femoral fracture with intercondylar extension – CPT 27513
• Open treatment of a distal femoral fracture of the medial or lateral condyle – CPT 27514
• Open treatment of a distal femoral epiphyseal separation – CPT 27519, typical in pediatric growth-plate injuries
• Repair of a nonunion or malunion of the femur distal to the head and neck – CPT 27470 without a graft, CPT 27472 with an autograft
• Supracondylar femoral osteotomy – CPT 27448 without fixation, CPT 27450 with fixation, when the cut is made in the distal third
• Open removal of deep hardware from the distal femur – CPT 20680, when the implant is in the lower one-third of the bone

Femoral shaft fixation is the case to slow down on. A distal-third shaft fracture repaired open belongs under 01360, while the same repair higher up the bone belongs under 01230.

The femur is split by the anesthesia series into an upper two-thirds and a lower one-third. Retrograde nailing through the knee doesn’t move the case into a knee code, because the treated bone is still the distal femur.

Anesthesia base units for 01360

CPT 01360 carries 5.0 anesthesia base units. The value comes from the American Society of Anesthesiologists (ASA) Relative Value Guide. CMS publishes the same nationwide figure in its anesthesia base unit file.

Base units represent the complexity and risk of the site and its typical procedures. They don’t move with case length or patient acuity. The number is fixed per code, and it’s the starting value in every reimbursement calculation.

The 5.0 units put 01360 above closed distal femur work at 4.0 and below open work on the upper two-thirds of the femur at 6.0. Verify the value annually against the current ASA guide, because base units can change.

How anesthesia reimbursement is calculated

Anesthesia doesn’t use the standard relative value unit system that drives most CPT codes. It uses a unit formula recognized by CMS and most commercial payers.

Reimbursement = (Base Units + Time Units) x Conversion Factor

Some commercial payers add modifying units for physical status or qualifying circumstances. Medicare doesn’t. Both variations are covered further down the page.

Time units and documentation requirements

Time units come from the documented start and end of anesthesia care. One time unit equals 15 minutes under Medicare rules. Some commercial payers use 10-minute or 12-minute intervals, so confirm the interval before you bill.

• Start time – when the provider begins preparing the patient for anesthesia, including positioning and monitoring setup
• End time – when the patient is handed off to recovery nursing and the provider is no longer in personal attendance
• Partial units – most payers allow rounding to the nearest unit, but the policy varies, so check it
• Source record – the signed anesthesia record, retrievable on audit and consistent with the OR log

Open distal femur cases run long enough that time units usually outweigh the base units. Practice management software like Pabau keeps timestamped events on the client record, which removes the most common audit trigger on these claims.

Worked example: Distal femur ORIF claim

A patient has an open reduction and internal fixation of a supracondylar femur fracture, billed by the surgeon as CPT 27511. The anesthesiologist personally performs the case and documents 120 minutes of anesthesia time.

The figure above is a national estimate before geographic adjustment. Your locality rate will differ, so confirm the current conversion factor for your Medicare Administrative Contractor (MAC) jurisdiction before you rely on it.

Medicare fee schedule and reimbursement rates

Medicare doesn’t publish a flat allowed amount for 01360. It pays the unit formula, and the conversion factor changes by locality and by year. The national anesthesia conversion factor for 2026 is $20.4976.

One change is easy to miss in 2026. CMS now runs two conversion factors, and the anesthesia rate for qualifying participants in an advanced alternative payment model is $20.5998 rather than $20.4976.

That difference is about half a percent per unit. On a 13-unit case it is worth roughly $1.33, which sounds trivial until you multiply it across a year of orthopedic trauma volume.

Fee schedule by payer type

To find your own figure, enter 01360 in the CMS Physician Fee Schedule lookup and select your MAC jurisdiction. The Medicare rate is a useful floor for contract negotiation rather than a prediction of what commercial payers will pay.

Modifiers used with 01360

Every anesthesia claim needs a provider modifier that says who delivered the care and under what supervision arrangement. A missing or mismatched modifier is one of the fastest routes to a denial on an 01360 claim.

Billing AA when the anesthesiologist directed a CRNA rather than performing the case is a compliance problem. CMS treats it as a false claim under the medical direction rules.

Physical status modifiers (P1-P6)

Physical status modifiers describe how sick the patient was at the time of anesthesia. They are appended after the provider modifier. Medicare pays no additional amount for P1 through P6. Some commercial payers do add units.

Open distal femur cases skew toward older trauma patients, so P3 and P4 are common. Append the modifier that matches the anesthesia record, and check the payer contract before you count those units as revenue.

Qualifying circumstances add-on codes (99100-99140)

Qualifying circumstances codes report conditions that made the anesthesia significantly harder. They are add-on codes, billed alongside 01360 and never alone. Medicare doesn’t pay extra for them, while many commercial payers do.

99100 comes up often on this code, because distal femur fractures cluster in older patients. Payers audit these add-ons, so the record has to describe how the condition changed anesthesia management. Noting the patient’s age isn’t enough.

CRNA and medical direction billing

Both anesthesiologists and Certified Registered Nurse Anesthetists (CRNAs) bill 01360. A CRNA working without physician medical direction appends modifier QZ and receives 100% of the Medicare allowable.

Independent CRNA billing depends on state law and on whether the state has opted out of the federal physician supervision requirement. Verify the current position for your state before you assume it applies.

When an anesthesiologist directs a CRNA, both submit their own claim. The physician bills QK for two to four concurrent cases, or QY for a single CRNA, and the CRNA bills QX. Each side receives 50%.

Medical direction also carries seven CMS requirements during the case. These include the pre-anesthesia evaluation, presence at induction and emergence, monitoring at critical moments, and remaining immediately available throughout.

Miss the documentation for any one of them and the claim drops from medical direction to medical supervision under modifier AD, which pays materially less. Long trauma cases with staggered start times are where this usually slips.

ICD-10 diagnosis codes that support the claim

Every 01360 claim needs an ICD-10-CM code that establishes medical necessity. The anesthesia claim should carry the same primary diagnosis the surgeon reported, which for this code usually sits in the S72 femur fracture family.

The ICD-10 seventh character describes the fracture, not the surgery. That is why “closed fracture” and open surgical treatment often sit on the same claim. Later visits in the same episode move on to D, the way S33.4XXD works for a pelvic injury.

Use character A for an initial encounter with an intact skin envelope, and B or C when the fracture itself was open. Choosing B because the surgeon operated is a documentation error waiting to be found on audit.

Knee diagnoses are the other warning sign. A meniscal derangement or knee osteoarthritis code paired with 01360 signals the wrong anesthesia code, because those conditions point to 01380, 01400, or 01402. Laterality also has to match the operative report.

Related CPT codes in the anesthesia series

01360 sits in the Knee and Popliteal Area range, 01320 to 01444. Its neighbors cover very different scopes: knee soft tissue, the knee joint, and the same femur segment treated a different way.

Base units for these codes come from the ASA Relative Value Guide and the CMS nationwide base unit file. Check the current descriptors with AAPC’s CPT code lookup before you submit.

Total knee arthroplasty is the clearest example of what 01360 is not. That case is 01402 at 7.0 base units, so billing 01360 instead undercodes the claim by two units and misstates the anatomy.

Documentation and medical necessity requirements

The anesthesia record has to support both the code choice and the units billed. On 01360 that means the record proves an open approach in the lower one-third of the femur, and proves the time.

• Anesthesia start and stop times – exact clock times rather than an estimated total, consistent with the OR log
• Surgical procedure and site – the surgeon’s CPT code and the femur segment treated, so the anesthesia code can be defended
• Approach – open or closed, stated plainly, because this is the line between 01360 and 01340
• Provider role – MD/DO, CRNA, or anesthesiologist assistant, plus the supervision arrangement billed
• Pre-anesthesia evaluation – history, physical, ASA physical status, and the anesthesia plan
• Intraoperative record – vital signs, airway management, and drugs administered
• Medical direction checklist – all seven CMS criteria, each time-stamped, whenever QK or QY is billed

Digital intake and pre-anesthesia forms help here, because a template captures the same fields every case. That consistency is what makes a record easy to defend two years later.

Rounding time to a habitual block, such as always billing 120 minutes for a distal femur fixation, is a recoupment risk. Anesthesia time is documented continuously, from preparation for induction until the provider is no longer in attendance.

Common billing errors and denial reasons

Denials on this code cluster around a short list, and most of them are preventable with a pre-submission check.

• Confusing 01360 with 01340 – the two codes share an anatomy and differ only on approach. Bill 01360 for open treatment and 01340 for closed treatment of the same segment.
• Reaching for 01360 on knee joint surgery – arthroscopy, ligament reconstruction, and knee replacement are not distal femur procedures. Those belong under 01380, 01400, or 01402.
• Treating 01360 as a catch-all – it has no not-otherwise-specified language. Nothing lands here by default just because the case involved the leg.
• Crossing the femur boundary – open fixation above the distal third is 01230, not 01360. Check where the fracture sits before choosing.
• Missing start or end time – the record needs exact clock times. An elapsed total with no anchor is the single most common denial trigger.
• Wrong provider modifier – billing AA for a directed case, or QK and QX without the seven documented criteria, which downcodes the claim to AD.
• ICD-10 laterality mismatch – a right femur procedure with a left femur diagnosis. It is a data entry slip that still costs 30 to 60 days.
• Expecting Medicare to pay add-ons – physical status and qualifying circumstances units are commercial-payer territory, not Medicare revenue.

Review denial patterns on this code quarterly. Code-selection errors repeat across a whole team, while arithmetic slips tend to be isolated, and the fix for each is different. Coding resources are available on the CMS ICD-10 codes page.

How Pabau supports anesthesia claim accuracy

Most 01360 denials start in the record long before anyone picks a code. Start and end times get handed over verbally. The approach is buried three paragraphs into the operative note. The modifier decision happens in the OR and never reaches the claim.

Pabau closes that distance. Claims management keeps the documentation and the claim in one system. The times, the approach, and the modifier travel together instead of being reassembled at billing.

Automated workflows flag a required field before the claim leaves the practice, and every claim stays visible from submission through payment. Your team chases fewer denials, and the ones that do arrive are easier to answer.

Those record habits pay off outside the operating room too. The same one-system setup supports osteopathy practices and the regenerative medicine teams that see these patients after a slow-healing fracture.

Keep anesthesia claims clean from OR to payment

Pabau gives anesthesia and surgical teams one place to capture times, approach, and modifiers, then track every claim through to payment. Fewer denials to chase, and faster answers when one lands.

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Conclusion

01360 is a narrow code wearing a broad label. It lives in the Knee and Popliteal Area range, but it pays for open surgery on the lower one-third of the femur and nothing else.

What decides the claim is the operative report. Read it for two facts, the approach and the femur segment, before anything reaches the claim form. Get those two right and 5.0 base units plus accurate time follow easily.

The trade-off worth remembering is a small one. Skipping that check saves a minute now and costs far more in rework later. Book a demo to see how Pabau keeps anesthesia documentation and claims in one place for orthopedic and surgical practices.

Continue your research

Is the fracture higher up the femur? CPT code 01230 covers open procedures on the upper two-thirds of the femur at 6.0 base units.

Coding the surgery side of a growth-plate case? CPT code 20150 covers excision of an epiphyseal bar and the documentation payers expect.

Billing anesthesia for another open orthopedic case? CPT code 20251 covers open vertebral body biopsy and how to document it.

Coding a nerve injury from the same trauma? ICD-10 code S34.5XXA covers injury of the lumbar, sacral, and pelvic sympathetic nerves.

Following the patient once the femur heals? Star excursion balance test sets out a scored protocol for lower-limb function.

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