5.3 Musculoskeletal and Skin

5.3 Musculoskeletal and Skin

Quick Answer: Traumatic fractures that are not present on admission (POA) sit in the CMS hospital-acquired condition (HAC) “falls and trauma” category and generally cannot act as a CC/MCC under the HAC payment provision when POA is N or U. Stage III and IV pressure injuries are a separate HAC category and feed Patient Safety Indicator (PSI) 03. Osteomyelitis needs acuity and site (and organism when known). Cellulitis is not osteomyelitis. Excisional debridement for ICD-10-PCS needs the root operation, body part, depth (skin, subcutaneous tissue, fascia, muscle, bone), and approach.

This Domain II section is still anatomy, pathophysiology, and terminology, but the same diagnoses drive Domain VI HAC/POA logic and Domain VIII PSI reporting. Learn the clinical distinctions here; later chapters return to the payment programs without merging them. This independent OpenExamPrep material does not claim Association of Clinical Documentation Integrity Specialists (ACDIS) approval or partnership.

Hospital-acquired condition payment provision (the 14 CMS HAC-POA categories that can stop a diagnosis from acting as a CC/MCC) is not the HAC Reduction Program (1% cut to hospitals in the worst Total HAC Score quartile, built from PSI-90 plus National Healthcare Safety Network infections). Fractures and pressure injuries appear in both conversations for different reasons. Keep the statutes separate on exam items.

Fractures: traumatic, pathologic, and HAC-relevant when not POA

CDI first classifies the fracture mechanism:

• Traumatic fracture from a fall or other injury (typically injury codes with a 7th character for encounter).
• Pathologic fracture from neoplasm, infection, or other bone disease when that is the documented mechanism.
• Osteoporotic current pathologic fracture when osteoporosis with current fracture is documented.

Do not code a traumatic hip fracture from an osteoporosis problem list if the provider describes a ground-level fall with a traumatic femoral-neck fracture. Do not code a traumatic fracture if the provider documents a pathologic fracture through a metastasis. Site, laterality, open versus closed when required, and encounter character all belong in the record before coding argues about the 7th character.

POA is the HAC hinge. Conditions present at the time of the inpatient order are POA Y, including fractures diagnosed in the emergency department or observation before that order. Fractures that occur after the inpatient order are POA N when documentation is clear. U means insufficient documentation; W means clinically undetermined. For the HAC payment provision, N and U generally prevent the condition from acting as a CC/MCC; W is paid like Y. Confirm the current CMS HAC-POA program instructions rather than treating memory as the rulebook.

CMS’s HAC-POA “falls and trauma” category includes fractures, dislocations, intracranial injury, crushing injury, burns, and other trauma. A hip fracture after an inpatient fall is the textbook example. Query POA when the timing of the injury is unclear. Do not use a yes/no query to introduce a new fracture diagnosis; POA yes/no (with unable to determine) is appropriate when the fracture is already documented.

Specified fractures can be CC- or MCC-level diagnoses on the current IPPS tables in other contexts. Speak in that principle, then apply HAC logic: a not-POA (or U) diagnosis in a HAC category generally will not buy severity under the payment provision even if the same code would have grouped as a CC or MCC had it been POA Y. This section does not reprint CMS code lists.

Scenario: the midnight fall

An 83-year-old is admitted for pneumonia. Night 2: found on the floor; new left hip pain; dawn radiograph: intertrochanteric fracture; hemiarthroplasty. The fracture was not POA. Documentation still must describe the event honestly for quality review and for the procedure. CDI’s concurrent checklist is: confirm the fracture diagnosis, laterality, site, traumatic versus pathologic, POA N, and the principal procedure. Do not write a query that says the fracture is needed for the MS-DRG.

Osteomyelitis: acuity, site, and not cellulitis

Osteomyelitis documentation should include:

• Acuity — acute, subacute, or chronic when known.
• Site and laterality — specific bone, not “bone infection.”
• Cause when documented — hematogenous, contiguous, post-procedural, device-related.
• Organism when identified (additional code).

Magnetic resonance imaging, labeled white-cell scan, probe-to-bone, exposed bone, and surgical pathology are indicators. They do not let coding assign osteomyelitis from radiology alone. Long-course intravenous vancomycin or piperacillin-tazobactam is a pharmacologic indicator of a serious infection pathway, not a bone diagnosis.

Cellulitis is a skin and subcutaneous infection. It can overlie osteomyelitis; it is not osteomyelitis. A diabetic foot with erythema, a probe-to-bone test, and marrow edema on MRI is a classic query: cellulitis only, osteomyelitis, both, another diagnosis, or other. Duration of antibiotics, orthopedic or podiatry operative plans, and histopathology support clinical validation if osteomyelitis is later challenged.

Unspecified osteomyelitis of an unspecified site is a weaker clinical and grouping story than specified acute osteomyelitis of a named bone. Specified osteomyelitis often changes severity capture compared with isolated cellulitis of a local skin site—verify the current CMS tables rather than memorizing an unofficial list. If chronic osteomyelitis is an old radiographic finding not treated this stay, it may fail UHDDS secondary criteria even if the word appears on a problem list.

Pressure injuries: stage III/IV HAC and PSI 03

Pressure injuries (still called pressure ulcers in some CMS HAC language) are staged with National Pressure Injury Advisory Panel constructs: stages 1–4, unstageable, and deep-tissue pressure injury. Stage III and stage IV pressure ulcers/injuries are a named CMS HAC-POA category. PSI 03 is the pressure-ulcer/injury rate inside the CMS PSI-90 composite used in the HAC Reduction Program. HAC payment provision and PSI 03 overlap clinically but are not the same rule set. A stage 2 injury is not in the HAC Stage III/IV category. Unstageable injuries should be queried for a stage when clinically possible; they still matter for quality surveillance depending on current measure specifications.

POA is decisive. A stage IV sacral injury documented on the admission skin exam is POA Y and is not a hospital-acquired Stage III/IV event for the payment provision. A stage 2 on admission that progresses to stage 4 is a documentation and quality event—query the stage at admission and the later stage, with dates, rather than collapsing the story into one unspecified ulcer.

Wound-care nurse and dietitian notes are rich indicators (measurements, undermining, nutrition). Under the 2026 ACDIS/AHIMA query guidelines, do not use yes/no solely from registered-dietitian or wound-nurse diagnoses to create a new provider diagnosis—use multiple-choice. The provider must own the stage and the diagnosis. “Decubitus,” “bedsore,” and “skin breakdown” without stage fail both HAC logic and PSI abstraction.

Scenario: unstageable on arrival

Emergency-department nurse: “black eschar, sacrum, unstageable.” Hospitalist: “decubitus.” Query for pressure injury/ulcer of the sacrum, stage (including unstageable or deep-tissue if that is the clinical truth), and POA. Do not mention PSI 03 or HAC penalties in the query text.

Cellulitis versus osteomyelitis, and debridement for PCS

When both soft-tissue infection and osteomyelitis are possible, sequence using UHDDS after study. If the admission is for intravenous antibiotics for cellulitis and osteomyelitis is an incidental chronic radiographic finding not treated this stay, do not promote untreated chronic osteomyelitis to PD. If the reason for admission is operative debridement of infected bone, osteomyelitis may be PD.

ICD-10-PCS debridement is not a Current Procedural Terminology mindset. The usual CDI questions:

• Root operation: Excision (cutting out a portion) for true excisional debridement versus Extraction (pulling or stripping) for many nonexcisional methods, or another root operation the procedure actually was (for example irrigation).
• Body part and laterality.
• Approach.
• Depth / tissue type: skin, subcutaneous tissue, fascia, muscle, bone—the deepest tissue the provider documents as excised or extracted.
• Device or qualifier as the tables require.

“Debrided the wound” is not PCS-ready. Operative notes should state instrument (scalpel, scissors, hydrosurgery, pulse lavage), tissue types removed, and whether bone was rongeured. Query the surgeon for depth and excisional versus nonexcisional when the note is silent. Do not infer bone debridement from an x-ray. Bedside enzymatic or autolytic “debridement” documented only by nursing is not automatically an operating-room excision.