Surgical reshaping or recontouring of the humerus — includes procedures such as shortening or lengthening of the humeral shaft, excluding procedures covered by 64876.
Verified May 8, 2026 · 5 sources ↓
- Medicare
- $1,001.69
- Total RVUs
- 29.99
- Global, days
- 90
- Region
- Elbow
Documentation requirements
What must appear in the operative or office note to support the claim.
Source · Editorial brief grounded in 5 cited references ↓
- Specify the clinical indication by name: humeral shortening, lengthening, angular correction, or bony recontouring — vague 'osteoplasty' without indication is an audit flag.
- Describe the surgical approach and level of the humerus addressed (proximal, shaft, distal).
- Document the type and method of stabilization used: plate and screws, intramedullary device, external fixator, or other fixation construct.
- State explicitly that 64876 (shortening of nerve with end-to-end anastomosis) does not apply — the parenthetical exclusion in the code descriptor requires this distinction when neurovascular structures are involved.
- If modifier 22 is appended, include a separate operative complexity statement quantifying additional time, difficulty, or unusual anatomical findings beyond standard osteoplasty.
- Measurements of correction achieved (length gained/lost in cm, degrees of angular change) strengthen medical necessity documentation, particularly for payer pre-auth reviews.
Applicable modifiers
Modifiers commonly billed with this code.
Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual
What this code covers
Source · Editorial summary grounded in 5 cited references ↓
CPT 24420 covers open surgical reshaping of the humerus, most commonly performed to correct humeral length discrepancy (shortening or lengthening), angular deformity, or bony prominence interfering with function or prosthetic fit. The procedure requires exposure of the humeral shaft, osteotomy or bone removal/addition, and stabilization — internal fixation is typically part of the same operative session. This is not a fracture repair code; it describes elective or reconstructive alteration of humeral architecture.
The 90-day global period means all routine post-op care through day 90 is bundled. Separate E/M visits during the global window require modifier 24 (unrelated problem) or, for decision-to-treat visits on the day of or day before surgery, modifier 57. Hardware removal performed during the global period that is directly related to the index procedure is bundled unless you can demonstrate it was unplanned — then modifier 78 applies. If hardware removal is for an unrelated reason, use modifier 79.
Site-of-service matters here: HOPD and ASC payments differ substantially (see the Site of Service comparison table). When performed bilaterally — rare but documented in limb-length correction contexts — append modifier 50 and bill a single line. Modifier 22 is appropriate when operative complexity significantly exceeds the typical osteoplasty, but requires a contemporaneous operative note justifying the increased work.
RVU & reimbursement
Component RVUs and Medicare national rate. Actual payment varies by GPCI locality.
Source · CMS Physician Fee Schedule, RVU26A · January 2026
| Work RVU | 13.39 |
| Practice expense RVU | 13.75 |
| Malpractice RVU | 2.85 |
| Total RVU | 29.99 |
| Medicare national rate | $1,001.69 |
| Global period | 90 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 | $1,001.69 |
HOPD (APC 5114) Hospital outpatient department | $7,413.38 |
ASC (PI G2) Ambulatory surgical center (freestanding) | $3,695.53 |
Common denial reasons
The recurring reasons claims for CPT 24420 get rejected.
Source · Editorial brief grounded in CMS NCCI edits, AAOS coding appeals, and cited references ↓
- Medical necessity not established — operative note lacks a documented functional deficit or clinical indication tied to the humeral deformity.
- Bundling with hardware removal (20680): payers often deny 20680 as inclusive when performed same-session; separation requires modifier 59 or XS with a distinct surgical step documented.
- Global period conflict — post-op E/M visits billed without modifier 24 or 25 during the 90-day window are automatically denied.
- Missing or inadequate preauthorization: high RVU reconstructive procedures on the humerus trigger prior auth requirements at most commercial payers.
- Incorrect site-of-service billing — professional fee billed under facility rates or vice versa when procedure moves from scheduled HOPD to ASC.
Frequently asked questions
Source · Generated from the editorial pipeline, verified against 5 cited references ↓
01Can I bill hardware removal (20680) separately when it's performed at the same session as 24420?
02What modifier applies if I need to return to the OR during the 90-day global for a complication related to the osteoplasty?
03Is 24420 appropriate for correcting a malunion of the humerus?
04Does a bilateral humeral osteoplasty exist clinically, and how do I bill it?
05When is modifier 22 justified for 24420?
06What ICD-10 codes most commonly support medical necessity for 24420?
Sources & references
Editorial content was developed using the following public sources. Last verified May 8, 2026.
Mira AI Scribe
Mira's AI scribe captures the specific indication (shortening, lengthening, angular correction), humeral level addressed, fixation construct used, and explicit confirmation that 64876 does not apply. It flags when the operative note omits measurements of correction or uses generic language like 'standard osteoplasty' — both of which trigger payer medical necessity reviews and audit scrutiny on a 90-day global procedure.
See how Mira captures CPT 24420 documentation