Orthopedic Medical Billing: Codes, Rules and Common Denials

Orthopedic billing is harder than most office-based billing because so much of the work is surgical. Most orthopedic procedures carry a Medicare global period, fracture care bundles the cast and routine follow-up into the procedure, arthroscopy has its own bundling rules, and many claims need anatomic modifiers and diagnosis codes with laterality and a 7th character. Getting paid correctly means coding each of those to the documentation, and tracking global periods so that follow-up visits are billed, or not billed, correctly.

The rules below are Medicare's, from CMS's global surgery guidance and the National Correct Coding Initiative (NCCI) policy manual. Many commercial payers follow similar rules, but each sets its own policies, so check the payer's policy for the date of service. Payment amounts vary by payer and locality and aren't covered here.

What does orthopedic billing cover?

The same steps as any practice's billing, with more surgery in the mix:

1. Registration, eligibility and benefits checks, and prior authorization where the plan requires it.
2. Coding: CPT and HCPCS codes for visits, procedures, injections, imaging and supplies; ICD-10-CM codes for the diagnoses.
3. Claim submission, then payment posting.
4. Follow-up on denials and unpaid claims.

For the full process, see what medical billing is.

Which codes do orthopedic practices bill most?

Orthopedic procedure codes sit in the CPT musculoskeletal section (20000 to 29999). Common examples, described in our own words:

In the 2026 Medicare fee schedule, the fracture, joint replacement and arthroscopy codes above all carry a 090 (90-day) global period, and 20610 carries a 000 global period. Check each code's global indicator in the Physician Fee Schedule look-up; don't assume it.

Office visits are billed with E/M codes at the level the documentation supports. The guides to arm fracture treatment codes, surgery CPT codes and injection CPT codes go into more detail.

Which diagnosis coding rules matter most?

Orthopedic diagnosis codes are among the longest in ICD-10-CM, and the official coding guidelines set rules that trip up many claims:

• Laterality. Many codes specify right, left or bilateral. If the record doesn't say which side, the unspecified-side code applies, but the guidelines say unspecified-side codes should rarely be used. Query the provider when the record conflicts.
• The 7th character. Fracture and injury codes need one. For a fracture, "A" applies while the patient is receiving active treatment, even if a new provider is seeing them. "D" applies once active treatment is complete and the patient is receiving routine care during healing. Other characters cover problems such as malunion, nonunion and sequelae.
• Injury or musculoskeletal condition. A current, acute injury is coded from the injury chapter. Chronic or recurrent conditions are generally coded from the musculoskeletal chapter.
• Every character. A code missing a required character is invalid.

For example, S42.301A is an unspecified fracture of the shaft of the right humerus at the initial encounter for a closed fracture, and M17.11 is unilateral primary osteoarthritis of the right knee.

How do global periods affect orthopedic billing?

For Medicare, a procedure with a 090 global period includes preoperative visits after the decision to operate (from the day before surgery), the surgery itself, and routine follow-up care for 90 days afterwards. Complications that don't need a return to the operating room are also included. A 010 procedure includes the procedure day and 10 days after it, and a 000 procedure includes the procedure day only.

Some services fall outside the package and are billed with a modifier, only when the record supports it:

• 57 for the visit at which the surgeon decided to perform a major (090) procedure.
• 25 for a significant, separately identifiable E/M service on the same day as a minor procedure, such as a joint injection. The decision to perform a minor procedure is part of the procedure.
• 24 for an E/M service during the postoperative period that is unrelated to the surgery. CMS says the documentation supporting it must be sent.
• 58 for a staged or related procedure during the postoperative period.
• 78 for an unplanned return to the operating or procedure room for a related procedure.
• 79 for an unrelated procedure during the postoperative period.

Medicare's rule for same-day visits with procedures may change: the CY 2027 Physician Fee Schedule proposed rule (July 2026) proposes reducing payment when an office E/M visit is billed on the same day as a procedure with a global period. Check the final rule before 2027.

What NCCI rules apply to fracture care and arthroscopy?

The NCCI Policy Manual's musculoskeletal chapter sets out several rules orthopedic practices meet every day:

• Casts and splints are included in fracture treatment. Codes for closed, percutaneous or open fracture treatment include applying the cast, splint or strapping, so casting codes aren't reported separately. The same practice doesn't bill for removing a cast it applied.
• Initial casting only. If a physician applies the first cast or splint without any other definitive treatment and expects to provide only that initial care, the casting code and a cast supply code may be reported, plus a visit if it is significant and separately identifiable.
• Closed converted to open. If a closed reduction fails and is converted to an open reduction at the same encounter, only the open procedure is reported.
• Arthroscopic converted to open. If an arthroscopic procedure is converted to an open one, only the open procedure is reported.

Anatomic modifiers (RT and LT, the finger modifiers F1 to F9 and FA, and the toe modifiers T1 to T9 and TA) tell the payer where each procedure was done. They are NCCI PTP-associated modifiers, so they can allow two codes that are normally bundled, but only when the procedures really were at separate sites. The CO-97 guide explains how bundling denials arise and when modifiers 59 and XS apply.

Where do orthopedic claims go wrong?

• Global period tracking. Follow-up visits billed during a global period, or unrelated visits not billed at all because staff assumed they were included.
• Modifier misuse. Modifier 25 or 59 added by default, or RT and LT missing.
• Diagnosis codes. Missing laterality, the wrong 7th character for the stage of care, or an unspecified code when the record is specific.
• Prior authorization. Many plans require authorization for some surgeries, imaging and other procedures, and each plan keeps its own list. In some states, knee arthroscopy for knee osteoarthritis is one of the services reviewed under CMS's WISeR prior authorization model in Original Medicare.
• Bundled supplies and casting. Casting codes billed with fracture treatment, or cast supplies billed when the rules don't allow it.

Each of these is fixed at the step that causes it: authorization checks at scheduling, coding audits against the operative note, and a global-period check in the billing system. The guide to why insurance claims get denied covers denials more broadly.

For billing support, see Highview's physician billing service, and billing by specialty.

Sources

• CMS, Global Surgery booklet, MLN907166 (December 2025): global periods, what the package includes and excludes, modifiers 24, 25, 57, 58, 78 and 79.
• CMS, Medicare NCCI Policy Manual (effective January 1, 2026): Chapter 1 (NCCI PTP-associated modifiers, including anatomic modifiers) and Chapter 4 (musculoskeletal system: arthroscopy, fractures and casting).
• CMS, PFS Relative Value Files, RVU26D: 2026 global periods for the codes listed.
• CMS, Search the Physician Fee Schedule.
• CMS and NCHS, ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027: laterality, 7th characters for fractures, injury versus musculoskeletal codes.
• CDC/NCHS, FY 2027 ICD-10-CM code descriptions: S42.301A and M17.11.
• CMS, CY 2027 Physician Fee Schedule proposed rule fact sheet.
• CMS, WISeR Model.