M67.50 identifies plica syndrome affecting the knee when the operative or clinical record does not specify right or left laterality.
Verified May 8, 2026 · 4 sources ↓
- Status
- Billable
- Chapter
- 13
- Related CPT
- 7
- Region
- Knee
Documentation tips
What should appear in the chart to support M67.50.
Source · Editorial brief grounded in 4 cited references ↓
- Record the affected side (right or left) by name in every note — a single laterality reference in the HPI or assessment unlocks M67.51 or M67.52 and avoids M67.50.
- Document the specific plica involved when known (medial, lateral, suprapatellar, infrapatellar) to support clinical specificity, even though ICD-10-CM does not further subdivide by plica type.
- Include MRI findings or arthroscopic confirmation — synovial thickening, plica fibrosis, or chondral changes — to support medical necessity for arthroscopic excision.
- Note the duration and nature of conservative care (physical therapy, NSAIDs, corticosteroid injection) before surgical intervention to satisfy payer step-therapy requirements.
- If plica syndrome is an incidental finding at arthroscopy for another primary diagnosis, sequence the primary condition first and add M67.50/51/52 as a secondary code.
Related CPT procedures
Procedure codes commonly billed with M67.50. Linking the right diagnosis to the right procedure is what establishes medical necessity.
Source · CMS LCDs · AAOS specialty guidance · claims-pattern analysis
Common coding pitfalls
The recurring mistakes coders make with M67.50 and adjacent codes.
Source · Editorial brief grounded in CDC ICD-10-CM tabular guidance, AAOS coding references, and cited references ↓
- Defaulting to M67.50 when the operative report, MRI order, or clinic note clearly names a single knee — use M67.51 (right) or M67.52 (left) instead; payers can deny unspecified codes when laterality is inferable from associated procedure codes.
- Confusing plica syndrome with meniscal pathology or patellofemoral pain and selecting the wrong parent category — plica syndrome is a synovial disorder under M67.5, not a meniscal or cartilage code.
- Billing M67.50 as a standalone diagnosis for arthroscopic plica excision without supporting documentation of failed conservative care, which is a common medical-necessity audit trigger.
- Omitting M67.5x entirely when plica is identified incidentally at arthroscopy performed for a separate primary indication — the secondary diagnosis still belongs on the claim if it was evaluated and treated.
Clinical context
Source · Editorial summary grounded in 4 cited references ↓
Plica syndrome results from irritation or thickening of a synovial plica — a fold of synovial membrane within the knee joint — producing anteromedial knee pain, clicking, and occasional pseudo-locking. M67.50 is the unspecified-laterality code under parent M67.5 (Plica syndrome). Use it only when the treating provider's documentation genuinely omits which knee is affected; if laterality is documented, M67.51 (right) or M67.52 (left) is required.
This code lives in Chapter 13 (Diseases of the musculoskeletal system and connective tissue, M00–M99) under the Other disorders of synovium and tendon category (M67). It groups to MS-DRG 557/558 (Tendonitis, myositis and bursitis, with/without MCC) for inpatient encounters. The parent category M67 carries Excludes1 notes for palmar fascial fibromatosis (M72.0), tendinitis NOS (M77.9-), and xanthomatosis localized to tendons (E78.2) — none of which overlap with plica syndrome, but confirm this code belongs to synovial pathology, not pure tendon pathology.
In orthopedic practice, plica syndrome is typically diagnosed after clinical exam (palpable medial plica, positive plica test) supported by MRI or arthroscopic findings. The unspecified code M67.50 is appropriate on a first-encounter claim only when the chart lacks explicit laterality — for example, a referral note that names the condition but omits the side. Avoid defaulting to M67.50 out of convenience; payer edits increasingly flag unspecified codes when the encounter type (unilateral surgery, unilateral MRI) makes laterality determinable.
Sibling codes
Other billable codes under M67.5 (laterality / anatomic variants).
Frequently asked questions
Source · Generated from the editorial pipeline, verified against 4 cited references ↓
01When is M67.50 appropriate versus M67.51 or M67.52?
02Does M67.50 require a 7th character?
03What CPT codes pair with M67.50 for arthroscopic plica excision?
04Which MS-DRG does M67.50 group to for inpatient encounters?
05Can M67.50 be used as a secondary diagnosis when plica is found incidentally at arthroscopy?
06Is plica syndrome covered under the M67 Excludes1 restrictions?
07What imaging supports the M67.50 diagnosis for payer review?
Sources & references
Editorial content was developed using the following public sources. Last verified May 8, 2026.
- 01CDC ICD-10-CM Tabular List 2026 (effective Oct 1, 2025)
- 02icd10data.comhttps://www.icd10data.com/ICD10CM/Codes/M00-M99/M65-M67/M67-/M67.50
- 03aapc.comhttps://www.aapc.com/codes/icd-10-codes/M67.50
- 04cms.govhttps://www.cms.gov/medicare/coding-billing/icd-10-codes
Mira AI Scribe
Mira's AI scribe captures the affected knee side, the clinical plica test result, MRI or arthroscopic findings (synovial thickening, plica band, associated chondral changes), and the conservative care history from the encounter note. That laterality capture upgrades M67.50 to M67.51 or M67.52 automatically, preventing an unspecified-code audit flag and protecting reimbursement for associated arthroscopic procedures.
See how Mira captures M67.50 documentation