Periprosthetic fractures present a unique challenge in medical coding because they sit at the intersection of trauma, pathology, and surgical complications. In the United States, millions of fractures are recorded annually, with trauma accounting for the vast majority. However, when a fracture occurs around an existing implant, coders must navigate specific ICD-10-CM guidelines to ensure compliance and prevent claim denials.
This comprehensive guide breaks down the exact rules for periprosthetic fracture coding, sequencing steps, category M97 applications, and real-world clinical examples.
What is a Periprosthetic Fracture?
A periprosthetic fracture is a bone fracture that occurs immediately adjacent to or surrounding a prosthetic joint implant.
Etiology: These fractures are typically caused by acute trauma (such as a fall) or underlying pathological conditions (such as severe osteoporosis or stress), rather than being a direct failure or defect of the prosthesis itself.
Classification Distinction: Because they do not involve a mechanical failure of the device, they are not classified as a device malfunction or mechanical complication. Instead, they are assigned dedicated codes within the M97 category of ICD-10-CM.
ICD-10-CM Periprosthetic Fracture Coding Structure
Accurate coding requires selecting the correct category M97 code based on the precise anatomical location and laterality.
1. Primary Diagnosis Location Codes (Category M97)
The entire code is determined by the specific joint location and side of the body:
M97.01- – Periprosthetic fracture around internal prosthetic right hip joint
M97.02- – Periprosthetic fracture around internal prosthetic left hip joint
M97.11- – Periprosthetic fracture around internal prosthetic right knee joint
M97.12- – Periprosthetic fracture around internal prosthetic left knee joint
(Additional codes exist within the M97 series for shoulder, elbow, ankle, and other skeletal joints).
2. Identifying the Encounter Type (7th Character Extension)
ICD-10-CM requires a 7th character to designate the stage of treatment:
A – Initial encounter (active, active treatment phase)
D – Subsequent encounter (routine healing, recovery, or routine care checks)
S – Sequela (complications or conditions resulting directly from a previous fracture, such as malunion or nonunion)
Periprosthetic Fracture Coding and Sequencing Rules
To ensure clean claims and satisfy payer edits, medical coders must follow strict sequencing protocols outlined in official coding guidelines.
Rule 1: The “Code First” Mandate and Etiology Sequencing
Per the official ICD-10-CM “Code first” instructions, reporting a periprosthetic fracture often requires at least two codes:
The Underlying Type & Cause: The specific nature of the fracture (e.g., traumatic fracture or pathological fracture due to osteoporosis) must be coded and sequenced first if known.
The Periprosthetic Code: The M97 category code is assigned as a secondary code to designate that the fracture involves an artificial joint.
(Note: Always check current tabular instructions, as primary clinical focus during the encounter can occasionally dictate principal diagnosis assignment if the injury itself is the sole focus of active surgical intervention).
Rule 2: Avoiding Traumatic Fracture Blocks (S00-T88) for Pure Complications
Periprosthetic fractures are categorized as complications of therapeutic care regarding anatomical proximity, but codes from the general S00–T88 traumatic injury block should be evaluated carefully against specific clinical notes. When coding pathological origins, look to metabolic bone disease codes (such as category M84).
Rule 3: Capturing Mechanical Complications (Secondary Codes)
If the periprosthetic break is explicitly linked to a prosthesis complication such as mechanical loosening, displacement, or structural failure a secondary complication code from the T84.- series (Complications of internal orthopedic prosthetic devices, implants, and grafts) must be appended.
Rule 4: External Cause Codes
If the fracture resulted from an external event (such as a fall from stairs or a slip), assign an external cause code from Chapter 20 (V00–Y99) to capture the full clinical picture and accident circumstances.
Real-World Coding Examples
Example 1: Traumatic Periprosthetic Knee Fracture
Clinical Scenario: A patient stumbles down four steps and sustains a fresh periprosthetic fracture at the lower end of the left femur surrounding a total knee replacement. The joint prosthesis itself is structurally intact and undamaged.
ICD-10-CM Coding Solution:
Principal / First-Listed Diagnosis: S72.402A (Unspecified fracture of lower end of left femur, initial encounter for closed fracture).
Secondary Diagnosis: M97.12XA (Periprosthetic fracture around internal prosthetic left knee joint, initial encounter).
External Cause Code: Assign appropriate V/W codes for the fall if documented.
Example 2: Pathological Periprosthetic Shoulder Fracture
Clinical Scenario: A patient recovering from a prior left shoulder replacement rolls over in bed and hears a snap. Medical examination reveals a periprosthetic fracture of the left humerus caused by underlying, severe osteoporosis. The implant itself is not fractured.
ICD-10-CM Coding Solution:
Principal / First-Listed Diagnosis: M84.422A (Pathological fracture, left humerus, initial encounter).
Secondary Diagnosis: M97.32XA (Periprosthetic fracture surrounding internal prosthetic left shoulder joint, initial encounter).
Additional Code: Report the underlying osteoporosis code (e.g., M81.0).
Summary Checklist for Medical Coders
[ ] Verify joint laterality (Right vs. Left) to avoid common cross-coding errors.
[ ] Identify whether the fracture is traumatic or pathological to determine correct sequencing order.
[ ] Append the correct 7th character extension (A, D, S) based on the phase of care.
[ ] Check for accompanying mechanical implant failures and assign secondary T84 codes when applicable.
