ICD-10-CM · Knee

M22.92

M22.92 identifies an unspecified disorder of the patella (kneecap) localized to the left knee, used when a specific patellar condition cannot be further classified.

Verified May 8, 2026 · 5 sources ↓

Status: Billable
Chapter: 13
Related CPT: 10
Region: Knee

Drawn from CDCICDAAPCOutsourceStrategies PatellofemoralVirginia Medicaid

Documentation tips

What should appear in the chart to support M22.92.

Source · Editorial brief grounded in 5 cited references ↓

Explicitly state 'left knee' or 'left patella' in the assessment — laterality must appear in the provider's note, not only in the coder's interpretation.
Document why a more specific M22 subcategory (chondromalacia, dislocation, patellofemoral syndrome) does not apply, or note that the diagnosis is pending further workup.
Record any imaging findings — sunrise/tangential patellar X-ray, MRI, or arthroscopic findings — that support a patellar disorder even if the exact diagnosis is still unspecified.
If conservative treatment has been trialed (physical therapy, bracing, NSAIDs), note duration and response to support medical necessity for advanced imaging or procedural intervention.
For bilateral presentations, document each knee separately so distinct laterality codes (M22.91 and M22.92) can be assigned rather than defaulting to M22.90.

Related CPT procedures

Procedure codes commonly billed with M22.92. Linking the right diagnosis to the right procedure is what establishes medical necessity.

Source · CMS LCDs · AAOS specialty guidance · claims-pattern analysis

27438 $781.92

Patellar arthroplasty with insertion of a prosthetic implant to resurface the kneecap.

27446 $1,047.45

Arthroplasty of the knee involving resurfacing of the condyle and tibial plateau in a single tibiofemoral compartment — medial OR lateral, not both.

27447 $1,159.35

Knee replacement surgery addressing both the medial and lateral tibiofemoral compartments, with or without resurfacing of the patella.

27486 $1,274.91

Revision of a total knee arthroplasty involving a single component, performed with or without the use of donor bone graft material.

27487 $1,574.52

Revision total knee arthroplasty with replacement of both the femoral and tibial components, with or without the use of allograft tissue.

27488 $1,099.89

Removal of a knee prosthesis — including total knee components and methylmethacrylate cement — with or without insertion of a spacer at the same operative session.

29877 $586.85

Knee arthroscopy with surgical debridement or shaving of articular cartilage (chondroplasty) — does not include meniscal work.

29874 $506.02

Arthroscopic knee surgery performed specifically to locate and remove loose or foreign bodies from within the joint space.

73564 $49.43

Radiologic examination of the knee consisting of four or more views, including oblique and tunnel projections, for a complete diagnostic workup.

73560 $34.40

Radiologic examination of the knee joint, one or two views, unilateral.

Common coding pitfalls

The recurring mistakes coders make with M22.92 and adjacent codes.

Source · Editorial brief grounded in CDC ICD-10-CM tabular guidance, AAOS coding references, and cited references ↓

Using M22.90 (unspecified knee) when the provider clearly documents the left side — always use M22.92 when laterality is established.
Defaulting to M22.92 when a more specific M22 code is supported by documentation; chondromalacia patellae (M22.42), patellofemoral disorder (M22.2X2), or recurrent dislocation (M22.02) should be coded instead.
Assigning M22.92 for acute patellar fractures or traumatic dislocations — those are injury (S-code) events, not chronic musculoskeletal disorders under M22.
Failing to update M22.92 to a specific code after arthroscopy or advanced imaging confirms a definitive patellar diagnosis; leaving the unspecified code on subsequent encounters invites audit scrutiny.
Applying a 7th-character extension to M22.92 — M-codes in this category do not use A/D/S encounter extensions.

Clinical context

Source · Editorial summary grounded in 5 cited references ↓

M22.92 is the left-knee-specific code under the M22.9 unspecified patellar disorder subcategory. Use it when the clinical documentation confirms a left-sided patellar problem but does not support a more specific M22 code — such as recurrent dislocation (M22.02), recurrent subluxation (M22.12), patellofemoral disorder (M22.2X2), chondromalacia patellae (M22.42), or other derangement (M22.3X2). It is an appropriate placeholder during the diagnostic workup phase, but should be replaced with a specific code once imaging, arthroscopy, or clinical examination yields a definitive diagnosis.

M22.92 falls within Chapter 13 (Diseases of the Musculoskeletal System and Connective Tissue, M00–M99) and is billable as a standalone code effective FY2026 (October 1, 2025). It groups into MS-DRG v43.0 DRGs 562 and 563 (Fracture, sprain, strain and dislocation except femur, hip, pelvis and thigh, with and without MCC). M-codes in this category do not require a 7th-character extension.

If the patient presents with bilateral patellar disorders, assign M22.91 (right) and M22.92 (left) separately — there is no bilateral code in the M22.9 subcategory. If only the left knee is affected and laterality is unambiguously documented as left, do not use M22.90 (unspecified knee).

Sibling codes

Other billable codes under M22.9 (laterality / anatomic variants).

M22.91

Unspecified disorder of patella, right knee

M22.90

Unspecified disorder of patella, unspecified knee

Frequently asked questions

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

01When should I use M22.92 instead of a more specific M22 code?

Use M22.92 only when the provider's documentation does not support a specific patellar diagnosis. If imaging or examination confirms chondromalacia, patellofemoral syndrome, recurrent dislocation, or another defined condition, code that specific subcategory instead.

02Can M22.92 be used for both the initial visit and follow-up encounters?

Yes, but reassess at each encounter. If subsequent imaging or arthroscopy yields a definitive diagnosis, update the code to the appropriate specific M22 subcategory. Leaving an unspecified code across multiple encounters without explanation can trigger medical necessity reviews.

03Is there a bilateral code for unspecified patellar disorder?

No. The M22.9 subcategory does not include a bilateral code. For bilateral unspecified patellar disorders, assign M22.91 (right) and M22.92 (left) as separate codes on the same claim.

04Does M22.92 require a 7th-character extension?

No. M-codes in Chapter 13 do not use 7th-character extensions (A/D/S). Those extensions apply to injury codes in the S-code range.

05Can M22.92 be used for a traumatic patellar injury sustained during a fall or collision?

No. Acute traumatic patellar injuries — fractures, acute dislocations — are coded with S-codes from Chapter 19. M22.92 is reserved for non-traumatic, disease-state patellar disorders in Chapter 13.

06What MS-DRGs does M22.92 map to?

Under MS-DRG v43.0, M22.92 groups to DRG 562 (Fracture, sprain, strain and dislocation except femur, hip, pelvis and thigh with MCC) and DRG 563 (same category without MCC), per icd10data.com.

07What is the parent code for M22.92, and when would I use it instead?

The parent code is M22.9 (Unspecified disorder of patella). M22.90 (unspecified knee) should only be used when the provider's documentation genuinely does not identify which knee is affected. If the left knee is documented, M22.92 is required over M22.90.

Sources & references

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

01CDC ICD-10-CM Tabular List 2026 — https://www.icd10data.com/ICD10CM/Codes/M00-M99/M20-M25/M22-/M22.92
02ICD-10-CM Official Guidelines for Coding and Reporting FY 2026 — http://stacks.cdc.gov/view/cdc/250974
03AAPC Codify M22.92 — https://www.aapc.com/codes/icd-10-codes/M22.92
04OutsourceStrategies Patellofemoral Syndrome Coding Guide — https://www.outsourcestrategies.com/blog/patellofemoral-syndrome-coding-and-billing-guidelines/
05Virginia Medicaid Hospital Manual Billing Instructions — https://vamedicaid.dmas.virginia.gov/sites/default/files/2022-10/Chapter-5%20Billing%20Instructions%20%28Hospital%29.pdf

Mira AI Scribe

Mira AI Scribe captures the documented laterality (left knee), the provider's statement that the patellar condition is not yet further specified, any imaging or arthroscopic findings referencing the left patella, and prior conservative care attempted. This prevents defaulting to the unspecified-knee code M22.90, avoids upcoding to a more specific M22 subcategory without supporting documentation, and reduces the risk of payer audits flagging a chronic unspecified code on repeat encounters.

See how Mira captures M22.92 documentation