Surgical · Knee

Add-on code for internal fixation applied during excision or curettage of a bone cyst or benign tumor of the femur, used when hardware such as screws or plates is placed to stabilize the defect site.

Verified May 8, 2026 · 5 sources ↓

Medicare: $236.48
Work RVU: 4.61
Global, days
Region: Knee

Drawn from AAPCAbosCgsmedicareCMS

Documentation requirements

What must appear in the operative or office note to support the claim.

Source · Editorial brief grounded in 5 cited references ↓

Identify the primary excision procedure (27355, 27356, or 27357) billed alongside 27358
Describe the hardware type placed (screws, plates, etc.) and anatomic location within the femur
Document the rationale for fixation tied to post-excision structural instability or defect size
Note whether cement augmentation was also used, separately from hardware, to avoid conflation of techniques
Record imaging (e.g., fluoroscopy) used intraoperatively to confirm fixation placement if applicable

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

22 Increased complexity LT Left side RT Right side 62 Co-surgeons 80 Assistant surgeon AS PA/NP/CNS assistant

What this code covers

Source · Editorial summary grounded in 5 cited references ↓

27358 is a add-on code reported alongside 27355, 27356, or 27357 — never standalone. It captures the additional work of placing internal fixation devices (screws, plates, or similar hardware) to stabilize the femur after curettage or excision of a bone cyst or benign tumor. When the defect left by lesion removal compromises structural integrity, fixation prevents pathologic fracture.

The global period is ZZZ, meaning it inherits the global period of the primary procedure it accompanies. Because 27358 is an add-on, modifier 51 is not appended. Bill it in addition to whichever primary excision code applies: 27355 (excision/curettage alone), 27356 (with allograft), or 27357 (with autograft). Attempting to bill 27358 with 27495 (prophylactic treatment) hits an NCCI edit — 27358 is the correct vehicle when fixation follows lesion excision.

Documentation must distinguish this from prophylactic fixation of an intact bone. The operative note should specify the hardware type and placement rationale tied directly to the post-excision defect. Cement augmentation (e.g., methylmethacrylate) used for defect filling does not automatically substitute for coded internal fixation — confirm hardware placement is documented independently.

RVU & reimbursement

Component RVUs and Medicare national rate. Actual payment varies by GPCI locality.

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU vs. total RVU

The work RVU (4.61) is the surgeon's own effort — the figure physician pay and productivity targets are built on. The total RVU (7.08) adds practice overhead and malpractice, and is what drives the Medicare payment below.

Work RVU	4.61
Practice expense RVU	1.47
Malpractice RVU	1
Total RVU	7.08
Medicare national rate	$236.48
Global period	days

Payment by site of service

Medicare pays different rates by setting. HOPD typically pays substantially more than ASC for the same procedure.

Source · CMS OPPS Addendum B·ASC HCPCS payment rates·2026

Setting	Medicare rate (national)
Office (PFS non-facility) Procedure performed in physician's office	$236.48

Common denial reasons

The recurring reasons claims for CPT 27358 get rejected.

Source · Editorial brief grounded in CMS NCCI edits, AAOS coding appeals, and cited references ↓

Billed as a standalone code — 27358 is an add-on and requires a primary excision code (27355, 27356, or 27357) on the same claim
Incorrect pairing with 27495 — NCCI edit bundles these; 27358 is the correct code when fixation follows lesion excision
Operative note documents only cement packing without confirmed hardware placement, failing to support the fixation claim
Modifier 51 incorrectly appended — add-on codes are exempt from multiple procedure reduction and should not carry modifier 51

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 5 cited references ↓

01Can 27358 be billed without a primary excision code?

No. 27358 is an add-on code and must be reported with 27355, 27356, or 27357. Submitting it alone will result in a denial.

02Should modifier 51 be added to 27358?

No. Add-on codes are exempt from modifier 51. Appending it is incorrect and may trigger a payment reduction or edit.

03What is the difference between 27358 and 27495?

27495 covers prophylactic fixation of an intact, at-risk bone. 27358 applies when fixation is placed specifically because of a defect created by lesion excision. An NCCI edit exists between the two — use 27358 when excision and fixation occur together.

04Does methylmethacrylate cement packing support billing 27358?

Not on its own. 27358 requires placement of internal fixation hardware (screws, plates). Cement alone does not satisfy the code definition. Document hardware placement explicitly.

05What is the global period for 27358?

ZZZ. The code inherits the global period of the primary procedure it accompanies (27355, 27356, or 27357), which typically carries a 90-day global.

06Can 27358 be reported when a patient has a prior TKR and a distal femoral lesion is excised?

Yes, if hardware is placed to stabilize the post-excision defect. The prior TKR does not change the coding; the operative note must still document the fixation hardware and its structural rationale.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

Mira AI Scribe

Mira's AI scribe captures hardware type, anatomic placement site, and the surgeon's stated rationale linking fixation to the post-excision femoral defect. It also flags which primary excision code (27355, 27356, or 27357) was performed, ensuring 27358 is never dropped onto the claim without its required companion code. This prevents the most common denial: submitting 27358 as a standalone procedure.

See how Mira captures CPT 27358 documentation