Osteochondrosis is a group of related disorders of bone and cartilage development in which the ossification center of an epiphysis, apophysis, or subchondral bone undergoes aseptic (non-infectious) ischemic necrosis, followed by a variable degree of revascularization, fragmentation, reossification, and remodeling — by definition requiring that the affected epiphysis was histologically normal prior to the ischemic event, which distinguishes osteochondrosis from congenital, infectious, or inflammatory epiphyseal disease. The pathophysiological sequence — ischemia → necrosis → fragmentation → revascularization → reossification → remodeling — is the unifying mechanism across all named forms, though the specific trigger (repetitive microtrauma, vascular compression, genetic predisposition, endocrine factors) varies by site and remains incompletely understood. Osteochondrosis is distinct from osteochondritis dissecans (OCD, M93.2x), which specifically refers to focal separation of articular cartilage and underlying subchondral bone forming a “loose body” or unstable fragment at a joint surface — OCD is considered by many authorities to be a form of osteochondrosis affecting articular surfaces, though ICD-10-CM classifies it separately under M93.2. The disease family is also distinguished from osteoarthritis (M15.x-M19.x), which is a degenerative cartilage condition of adults, and from osteomyelitis (M86.x), which is infectious bone necrosis. In ICD-10-CM, osteochondroses are coded under M91 (juvenile — hip and pelvis), M92 (juvenile — other sites), and M93 (other osteochondropathies including OCD and adult forms), all requiring site-specificity and laterality at the highest level of granularity available.
“bone” — the Greek combining form for bone; parallel to Latin os/ossis; appears in virtually all medical terms related to bone structure, disease, and metabolism (cf. osteoporosis, osteomyelitis, osteoblast)
chondro-
Greek χόνδρος (chóndros)
“cartilage,” “grain,” “granule” — combining form denoting cartilage or cartilaginous structure; the juxtaposition of osteo- + chondro- reflects the composite bone-cartilage pathology of this disease group, in which both tissues are affected
Noun-forming suffix — “condition of,” “process of,” “abnormal increase or state” — a highly productive disease-naming suffix in medicine denoting a pathological state or process (cf. necrosis, fibrosis, thrombosis)
The word entered English in the late 19th - early 20th century as osteochondrosis (noun), constructed directly from Greek ὀστέον (ostéon, “bone”) + χόνδρος (chóndros, “cartilage”) + -ōsis (“condition of”) — literally meaning “a condition of bone and cartilage [disease].” The suffix -osis (as opposed to -itis, which denotes inflammation) was deliberately chosen because osteochondrosis is fundamentally a degenerative/ischemic condition, not an inflammatory one — though early researchers used the term “osteochondritis” interchangeably, which survives today in the retained clinical term osteochondritis dissecans. The combining form osteo- is one of the most productive Greek roots in medicine, appearing in osteoporosis, osteomyelitis, osteosarcoma, osteoblast, and osteoclast. The combining form chondro- connects osteochondrosis to chondromalacia, chondroplasty, chondrosarcoma, and chondrocyte. The suffix -osis is ubiquitous in pathological nomenclature: necrosis, fibrosis, thrombosis, scoliosis, and stenosis.
🔀 ALIASES / ALTERNATE TERMS
Osteochondropathy(broader clinical synonym encompassing osteochondrosis and related bone-cartilage disorders; used in ICD-10-CM category title M93 — “Other Osteochondropathies”)
Juvenile osteochondrosis(the dominant form — occurs exclusively in skeletally immature patients during active growth; by definition self-limiting once the physis fuses; coded under M91-M92 by site and laterality)
Legg-Calvé-Perthes disease(osteochondrosis of the femoral head — the most clinically significant juvenile form; ischemic necrosis of the capital femoral epiphysis; M91.11 right, M91.12 left, M91.10 unspecified)
Osgood-Schlatter disease(osteochondrosis/apophysitis of the tibial tubercle — traction-type; see also apophysitis note; M92.541 right, M92.542 left, M92.549 unspecified)
Scheuermann disease(osteochondrosis of the vertebral body ring apophyses — produces the classic rigid thoracic kyphosis “Scheuermann kyphosis”; coded under M42.00-M42.09 per spinal region)
Kienböck disease(osteochondrosis of the lunate — ischemic necrosis of the carpal lunate in adults; coded under M93.11 right, M93.12 left, M93.10 unspecified)
Freiberg disease(osteochondrosis of the metatarsal head — most commonly second metatarsal; coded under M92.771 right foot, M92.772 left foot, M92.779 unspecified)
Köhler disease(osteochondrosis of the tarsal navicular in children; coded under M92.6x — Juvenile osteochondrosis of tarsus; M92.61 right, M92.62 left)
Panner disease(osteochondrosis of the capitellum of the humerus in young throwers — distinct from OCD of the capitellum by patient age and intact articular cartilage; M92.01 right, M92.02 left)
Osteochondritis dissecans (OCD)(subchondral osteochondrosis with articular cartilage involvement producing a potentially loose osteochondral fragment; the most surgically relevant form; coded under M93.2x with site and laterality — knee M93.261/M93.262, ankle M93.271/M93.272, elbow M93.221/M93.222)
🔗 RELATED TERMS
Avascular necrosis (AVN) — synonymous with osteonecrosis; the underlying pathophysiological mechanism of osteochondrosis; occurs when blood supply to the ossification center is interrupted; in adults, AVN of the femoral head is coded under M87.x (not M91.x); the juvenile form of femoral head AVN is Legg-Calvé-Perthes, M91.1x
Osteonecrosis — the broader ICD-10-CM category (M87.x) for avascular necrosis in adults; does not overlap with M91-M93, which are exclusively pediatric or specific named osteochondropathies; distinguish carefully when the patient is skeletally mature
Ossification center — the primary anatomic target of osteochondrosis; a secondary ossification center (epiphysis or apophysis) supplied by a vulnerable end-arterial blood supply that makes it susceptible to ischemia during periods of rapid growth
Epiphysis — the articular end of the long bone containing the ossification center; the site of osteochondrosis in Legg-Calvé-Perthes, Panner disease, Kienböck disease, and Freiberg disease
Apophysis — the non-articular secondary ossification center at a tendon/ligament insertion; the site of traction-type osteochondrosis (Osgood-Schlatter, Sinding-Larsen-Johansson, Sever’s disease) — see apophysitis note
Osteochondritis dissecans — the articular subtype of osteochondrosis characterized by focal separation of subchondral bone and overlying cartilage; classified under M93.2x in ICD-10-CM; distinguished from classic osteochondrosis by the presence of articular cartilage involvement and the risk of intra-articular loose body formation
Loose body — a free-floating osteochondral fragment within a joint, classically resulting from OCD; its presence alters CPT selection (arthroscopic removal = 29874 for knee) and ICD-10 documentation must specify the joint
Subchondral bone — the layer of bone immediately beneath articular cartilage; the zone of ischemic necrosis in OCD; its integrity determines lesion stability (stable = intact cartilage and bone bridge; unstable = detached fragment)
Chondromalacia — softening and fibrillation of articular cartilage, often a secondary finding associated with osteochondrosis affecting articular surfaces; coded under M94.2x; distinct from osteochondrosis in that the primary pathology is cartilage degeneration rather than ossification center necrosis
Legg-Calvé-Perthes disease — the most clinically significant named osteochondrosis; involves the capital femoral epiphysis in children aged 4-10; classified by Herring lateral pillar classification (A/B/C) which guides surgical decision-making but does not affect ICD-10 code selection
Scheuermann kyphosis — osteochondrosis of vertebral ring apophyses producing rigid thoracic hyperkyphosis (>45°) with characteristic Schmorl’s nodes and anterior vertebral wedging; coded under M42.0x (juvenile) per spinal region — a commonly missed code when coders see “kyphosis” and default to M40.x
Salter-Harris fracture — traumatic physeal injury that can simulate or complicate osteochondrosis; important differential in the young patient presenting with joint pain and limping; coded under S-series fracture codes, not M91-M93
Bone scan — nuclear medicine scintigraphy used to evaluate vascularity and disease activity in osteochondrosis; three-phase bone scan (78315) shows decreased uptake (cold defect) in acute ischemia and increased uptake during revascularization phase; used for both diagnosis and surgical timing
MRI without contrast — the gold standard imaging modality for osteochondrosis and OCD; delineates cartilage integrity, subchondral edema, and lesion stability; CPT 73221 (upper extremity joint), 73721 (lower extremity joint), 72141 (spine)
CODING CORNER
🏥 ICD-10-CM CODES
Juvenile Osteochondrosis — Hip & Pelvis (M91.x — Laterality Required)
Code
Description
M91.10
Juvenile osteochondrosis of head of femur [Legg-Calvé-Perthes], unspecified leg
M91.11
Juvenile osteochondrosis of head of femur [Legg-Calvé-Perthes], right leg
M91.12
Juvenile osteochondrosis of head of femur [Legg-Calvé-Perthes], left leg
M91.20
Coxa plana, unspecified hip (residual deformity after Perthes — head flattening)
M91.21
Coxa plana, right hip
M91.22
Coxa plana, left hip
M91.80
Other juvenile osteochondrosis of hip and pelvis, unspecified leg
M91.81
Other juvenile osteochondrosis of hip and pelvis, right leg
M91.82
Other juvenile osteochondrosis of hip and pelvis, left leg
M91.90
Juvenile osteochondrosis of hip and pelvis, unspecified, unspecified leg
M91.91
Juvenile osteochondrosis of hip and pelvis, unspecified, right leg
M91.92
Juvenile osteochondrosis of hip and pelvis, unspecified, left leg
🔧 COMMON CPT CODES (Osteochondrosis-Related Diagnosis & Treatment)
CPT Code
Description
29885
Arthroscopy, knee, surgical; drilling for osteochondritis dissecans with bone grafting, with or without internal fixation (including debridement of base of lesion) — unstable OCD with bone graft
29886
Arthroscopy, knee, surgical; drilling for intact osteochondritis dissecans lesion — stable OCD, no bone graft, no internal fixation
29887
Arthroscopy, knee, surgical; drilling for intact osteochondritis dissecans lesion with internal fixation — stable OCD with fixation added
29874
Arthroscopy, knee, surgical; for removal of loose body or foreign body (e.g., osteochondritis dissecans fragmentation, chondral fragmentation) — OCD with free loose body
29877
Arthroscopy, knee, surgical; debridement/shaving of articular cartilage (chondroplasty) — chondral surface treatment in OCD
29879
Arthroscopy, knee, surgical; abrasion arthroplasty (includes chondroplasty where necessary) or multiple drilling or microfracture — subchondral stimulation for cartilage defect
27415
Osteochondral allograft, knee — open osteochondral allograft transplantation for large OCD defects or Kienböck-type lesions in the knee
27416
Osteochondral autograft(s), knee (e.g., mosaicplasty) — 1 or more plugs; open procedure for OCD cartilage restoration
29867
Arthroscopy, knee, surgical; osteochondral allograft (e.g., mosaicplasty) — arthroscopic version of allograft implantation
Level IV surgical pathology, gross and microscopic examination (osteochondral biopsy or excised OCD fragment specimen — always billed with surgical CPT)
⚠️ Coding Note: The most critical ICD-10-CM distinction in this code family is M91-M92 (juvenile osteochondrosis — non-articular forms) vs. M93.2x (osteochondritis dissecans — articular form with potential loose body); these are NOT interchangeable, and payer systems including Medicare Advantage plans and BCBS commercial will match the diagnosis code to the surgical CPT for medical necessity — billing 29885 or 29886 against M91.11 (Legg-Calvé-Perthes) is a mismatch that will trigger a medical necessity edit or denial because those arthroscopic OCD codes are designed for articular lesions, not avascular necrosis of the femoral head. For Scheuermann disease (M42.04), a common undercoding pattern in inpatient profee claims is assignment of generic kyphosis codes (M40.204-M40.209) when the documentation clearly states “Scheuermann kyphosis,” “Scheuermann disease,” or “vertebral osteochondrosis” — M42.04 is the medically correct and more specific code and should always be used when the eponym or osteochondrosis etiology is documented. For OCD surgical coding, the three knee arthroscopy codes are frequently confused: 29886 = stable OCD, drilling only, no graft, no fixation; 29887 = stable OCD, drilling + internal fixation; 29885 = OCD with bone grafting (with or without fixation) — the op report must explicitly document whether bone graft was used and whether the lesion was intact before the correct code can be assigned. Panner disease (M92.01/M92.02) in a child under 12 and OCD of the capitellum (M93.221/M93.222) in an adolescent over 12 are clinically and radiographically distinct — Panner is a self-limiting osteochondrosis with an intact articular surface and does NOT require surgical intervention or arthroscopy; OCD of the capitellum may require surgical fixation or removal — do not conflate these when a young throwing athlete presents with lateral elbow pain. Modifier -59 applies when 29874 (loose body removal) and 29885 or 29886 (drilling) are performed at the same arthroscopic session on the same knee — confirm payer-specific NCCI bundling rules, as some payers bundle these without modifier exception.
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