ICD code M91.0 – Juvenile osteochondrosis of pelvis

Key takeaways

M91.0 is the billable ICD-10-CM code for juvenile osteochondrosis of the pelvis, valid for fiscal year 2026 and complete at four characters.

Its official inclusion terms are juvenile osteochondrosis of the acetabulum, the iliac crest [Buchanan], the ischiopubic synchondrosis [van Neck], and the symphysis pubis [Pierson].

Legg-Calve-Perthes disease is not an M91.0 term. It is the descriptor for M91.1, while coxa plana is M91.2 and pseudocoxalgia is M91.3.

Those three hip-site subcategories each need a fifth character for laterality, so M91.1, M91.2 and M91.3 are not billable on their own. M91.0 needs no such character.

Pabau integrates with Claim.MD to support electronic claim submission and real-time eligibility checks for codes including M91.0, reducing denial risk before claims reach the payer.

ICD-10 Code M91.0: Code details and descriptor

ICD-10 Code M91.0 carries the full descriptor “Juvenile osteochondrosis of pelvis” in the ICD-10-CM tabular list.

That list is maintained by the Centers for Medicare and Medicaid Services (CMS). The code has been valid and billable since ICD-10-CM’s U.S. adoption in 2015, and it remains active for fiscal year 2026. The table below provides the key reference data at a glance.

Clinical description: What juvenile osteochondrosis of the pelvis means

Juvenile osteochondrosis of the pelvis is a growth disturbance at a pelvic ossification center in a skeletally immature patient. Blood supply or mechanical loading at the growth center is disrupted, and the bone passes through fragmentation, sclerosis, and then reossification.

M91.0 gathers four of these presentations under one code, each named for the pelvic structure involved. Because the skeleton is still growing, remodeling can restore near-normal architecture once the process resolves.

Presentation depends on which structure is affected. Osteochondrosis of the ischiopubic synchondrosis, known as van Neck disease, appears most often in children between roughly four and twelve years old. It is frequently bilateral and frequently asymptomatic. On X-ray, its swollen and irregular appearance can be mistaken for osteomyelitis or a bone tumor.

Iliac crest osteochondrosis, or Buchanan disease, tends to appear in active adolescents as pain along the upper rim of the pelvis. Symphysis pubis involvement, Pierson disease, presents with pubic or groin pain. Acetabular osteochondrosis shows as irregular ossification of the hip socket itself rather than the femoral head.

Imaging is what carries the diagnosis. X-ray findings include fragmentation, flattening, or increased density at the affected ossification center. MRI adds bone marrow edema and early avascular change, and it helps rule out the infection or tumor that van Neck disease can imitate. The imaging report is also where the coder finds the named pelvic structure that M91.0 depends on.

Inclusion terms and synonyms for ICD-10 Code M91.0

The ICD-10-CM tabular list names four inclusion terms under M91.0. When the physician’s note uses any of them, M91.0 is the code to assign. The CDC/NCHS ICD-10-CM official tool lists these four terms and no others.

• Osteochondrosis (juvenile) of acetabulum – the socket side of the hip joint, which is pelvic bone rather than femur
• Osteochondrosis (juvenile) of iliac crest [Buchanan] – Buchanan disease, affecting the iliac crest apophysis along the upper rim of the pelvis
• Osteochondrosis (juvenile) of ischiopubic synchondrosis [van Neck] – van Neck disease, affecting the cartilage bridge between the ischium and the pubis
• Osteochondrosis (juvenile) of symphysis pubis [Pierson] – Pierson disease, affecting the midline joint between the two pubic bones

Three terms coders often expect to find here are absent from that list. Legg-Calve-Perthes disease, coxa plana, and pseudocoxalgia are the descriptors for M91.1, M91.2, and M91.3. All three sit at the femoral head, not the pelvis, so none of them is a synonym for M91.0. The acetabulum is the only inclusion term that reaches into the hip joint, and it is pelvic bone, so it stays with M91.0.

Query the physician when a note names a hip condition without saying which bone is involved. The answer decides between M91.0 and the M91.1 through M91.4 range, and it protects the claim from a site-specificity denial. The routing below shows where each documented site sends the claim.

Exclusion notes: What M91.0 does not cover

ICD-10-CM exclusion notes define the boundaries of M91.0 and govern whether conditions may be coded together. Misreading these notes is a common source of coding errors and subsequent claim denials.

Adjacent codes in the M91 block: Avoiding common miscoding

The M91 category – “Juvenile osteochondrosis of hip and pelvis” – holds seven subcategories. M91.0 is the only one without a laterality character. Every other subcategory needs a fifth character of 0, 1, or 2 for unspecified, right, or left.

Those conditions sit in one hip, so the tabular list demands a side. The table below maps the whole category for quick reference during code selection. The same site-first logic runs through the rest of the ICD-10-CM codes index.

Differentiating M91.0 from Legg-Calve-Perthes disease and avascular necrosis

Legg-Calve-Perthes disease is the single most common source of M91.0 miscoding, and it is never M91.0. LCP is avascular necrosis of the femoral head, and ICD-10-CM gives it its own subcategory, M91.1, with a laterality character. According to the WHO ICD-10 browser, the M91 block is organized by anatomical site rather than by eponymous disease name.

Avascular necrosis adds a second layer, because a skeletally mature patient with femoral head necrosis is coded to M87.- instead. The table below consolidates the four scenarios coders confuse most often into a single decision reference.

Documentation requirements for accurate M91.0 coding

A physician note that supports M91.0 must do more than mention a diagnosis name. The note has to confirm both the clinical diagnosis and the patient characteristics that make the code appropriate. Missing any of the elements below raises the likelihood of a medical necessity denial or an audit finding.

• Confirmed diagnosis with an approved descriptor or inclusion term. The note must state juvenile osteochondrosis of the pelvis, or name one of the four inclusion terms. A general reference to “hip pain” or “pelvic disorder” is insufficient.
• Skeletally immature status. M91.0 applies only to juvenile patients. The note should document patient age and, where available, confirm open physes on imaging. Without evidence of skeletal immaturity, payers may reject the code as clinically inconsistent.
• Imaging findings. X-ray findings such as epiphyseal flattening, fragmentation, or increased density support the diagnosis, as do MRI findings of bone marrow edema or signal change. The imaging report should sit in the medical record and be available for claim review.
• Anatomical site specificity. The note must name the pelvic structure involved, not the hip joint generally. This is the single most important element, because a note naming the femoral head routes the claim to M91.1 through M91.4 instead.
• Absence of conflicting diagnoses. The note should not simultaneously document SCFE (M93.0-), which has an Excludes1 relationship with M91.0. If both conditions are considered, the treating physician should clarify which is the confirmed diagnosis.

A structured pre-submission checklist for pediatric musculoskeletal codes reduces rework across the whole M91 range. Each of the five elements above converts neatly into a checklist line that a biller confirms before the claim goes out.

Payer requirements and prior authorization for M91.0 claims

M91.0 is primarily a pediatric diagnostic code, which means Medicare is rarely the primary payer. The payers most likely to process M91.0 claims are commercial insurers and Medicaid managed care plans covering children. An electronic eligibility check before the appointment confirms active coverage and any authorization requirement in advance. Payer-specific considerations for M91.0 include the following:

• Commercial insurers – most require a confirmed diagnosis with supporting imaging before authorizing orthopedic management. The diagnosis code M91.0 alone does not trigger authorization. It is the associated procedure codes for evaluation, imaging, and physical therapy that payers gate behind prior authorization.
• Medicaid managed care – authorization thresholds vary by state. Pediatric musculoskeletal evaluations in the initial diagnostic phase are commonly covered without prior authorization. Ongoing physical therapy or surgical consultation usually does require authorization, with M91.0 attached as the supporting diagnosis.
• Medicare – pediatric diagnostic codes are almost never primary payer scenarios under Medicare. An elderly patient assigned M91.0 would be a rare edge case, and the claim would face a medical necessity challenge. The code descriptor is explicitly juvenile, so flag these scenarios before submission.

Practices that manage orthopedic and pediatric patients should build these authorization rules into the pre-visit workflow. Knowing which plans require authorization for which procedure codes alongside M91.0 prevents the most common authorization-related denials.

Common denial reasons for M91.0 claims and how to avoid them

Most M91.0 denials trace back to one of five predictable root causes, and each one is preventable if caught before submission. Applying denial management discipline at the code level lets billing teams repair a thin note before submission rather than during an appeal. A pre-submission review step for pediatric orthopedic claims should check each of the criteria below.

ICD-10 Code M91.0 in context: Related procedure codes

M91.0 rarely appears on a claim in isolation. It is paired with procedure codes that reflect the evaluation, imaging, or treatment of juvenile pelvic osteochondrosis. It also travels onto physical therapy claims as a supporting diagnosis, not only onto orthopedic evaluation claims. The pairings below represent the most commonly billed combinations for this diagnosis.

Pair M91.0 with any of these CPT codes and omit the imaging documentation or the authorization reference number, and the denial is predictable. Attaching both to the record before submission is what keeps these pairings clean.

How Pabau keeps M91 claims accurate before submission

Most practices check M91 coding by hand. The radiology report sits in one system, the code lookup in another, and the claim in a third. The code gets retyped at each step, and every retype is a chance to drop the fifth character or pick the wrong subcategory.

Practice management software like Pabau keeps the diagnosis attached to the patient instead. The code is recorded at the visit and carried straight onto the claim, so nobody rekeys it. Pabau’s claims management software then submits electronically through Claim.MD and tracks the remittance back to the invoice.

For a pediatric orthopedic caseload, that means fewer M91 claims returned for a missing laterality character or an unsupported juvenile diagnosis. The eligibility check runs before the appointment, so an authorization problem surfaces while the visit can still be rescheduled.

Reduce claim denials on pediatric musculoskeletal codes

Pabau integrates with Claim.MD to validate ICD-10-CM codes and run eligibility checks before claims reach the payer. See how the workflow handles codes like M91.0 from documentation through to remittance.

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Conclusion

ICD-10 Code M91.0 is a site-specific code, and the site is the pelvis. It covers osteochondrosis of the acetabulum, the iliac crest, the ischiopubic synchondrosis, and the symphysis pubis.

Three errors cost practices money here. Coders reach for M91.0 on a Legg-Calve-Perthes diagnosis, skip the documentation of juvenile status, or violate an Excludes1 relationship. All three are caught by a structured pre-submission review.

The bone named in the radiology report is the whole decision, and confirming it takes a coder seconds. Build that one check into the review and the M91 denial rate falls without any other change. To see how Pabau handles M91.0 from documentation through to payment, book a demo.

Continue your research

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