01Approach to the Critical Patient/attcp59

Immediate priorities

›Urgent orthopedic consultation triggers

›Mechanical symptoms at presentation

›Locking or true catching

›Acute loss of range of motion

›Inability to bear weight

›Large tense effusion

›Aspirate if tense and painful

›Bloody fluid suggests unstable fragment or loose body

›Suspected displaced loose body

›Palpable intra-articular fragment

›Acute loss of extension or flexion

›Hemodynamic and systemic stability

›Vital signs baseline

›Heart rate and blood pressure

›Temperature to exclude septic arthritis

›If fever and joint effusion, exclude septic arthritis before OCD management

›Joint aspiration and fluid analysis

›Urgent orthopedic or emergency consultation

Key decision points

›Skeletal maturity determination

›Open physes on radiograph

›Juvenile OCD — greater healing potential

›Higher nonoperative success rate (~50–65%)

›Closed physes on radiograph

›Adult OCD — poorer prognosis

›Greater propensity to instability and need for surgery

›Lesion stability assessment

02History/hx77

Presenting symptoms

›Core symptom complex

›Knee pain

›Typically vague, poorly localized

›Activity-related and insidious in onset

›Worsened with weight-bearing and impact activities

›Mechanical symptoms indicating instability

›Locking or true catching

›Giving way or popping

›These suggest unstable lesion or loose body

›Effusion and stiffness

›Swelling after activity

›Decreased range of motion

›Morning stiffness

Symptom characterization

›Temporal and activity context

›Duration and onset pattern

›Gradual onset vs. acute worsening

›Relationship to specific activities

›Sport and training history

›Type and frequency of sport

›Recent increases in training volume

›Year-round single-sport specialization

›Weight-bearing status

›Pain with walking or stairs

›Ability to run or pivot

Risk factors

›Demographic and activity risk profile

›Age 10–20 years (peak 11–15 years)

›Male sex (2–4x higher incidence)

›Black race associated with higher odds of OCD

›High-impact sports participation

›Basketball most common in males

›Soccer most common in females

›Repetitive microtrauma and mechanical overload

›Anatomic and metabolic factors

›Varus alignment associated with medial femoral condyle OCD

›Obesity increases mechanical overload

›Nutritional deficiencies, especially vitamin D

›Smoking in older adolescents predicts lesion instability

Alarm features

›High-risk historical features requiring urgent evaluation

›Mechanical symptoms

›Locking, catching, or giving way

›Indicate possible loose body or unstable fragment

›Acute loss of range of motion

›Suggests fragment displacement

›Age and maturity risk factors

›Age >=14 years with open physes — higher instability risk

›Closing or closed physes — reduced healing potential

›Rapidly progressive symptoms despite activity modification

Review of systems

›Systemic and multi-joint assessment

›Other joint involvement

›Elbow pain (second most common OCD site)

›Ankle pain (talus OCD)

›Bilateral knee symptoms in up to one-third

›Constitutional symptoms

›Fever, weight loss (to exclude malignancy or infection)

›Fatigue or malaise

›Rheumatologic screen

›Morning stiffness >60 minutes

›Rash, eye symptoms, oral ulcers

›Family history of inflammatory arthritis

›Growth and development history

›Pubertal stage (relevant to physeal status)

›Menstrual history in females (relative energy deficiency in sport)

Past medical and family history

›Relevant prior history

›Previous OCD diagnosis

›Same or contralateral knee

›Other joint involvement

›Prior knee injury or surgery

›Previous trauma

›Ligamentous injury history

›Bone health conditions

›Vitamin D deficiency

›Endocrine disorders

›Skeletal dysplasia or growth disorders

›Family history

›OCD in first-degree relatives (genetic predisposition)

›Early-onset osteoarthritis

›Skeletal dysplasias

03Physical Exam/exam59

Gait and weight-bearing assessment

›Gait analysis

›Antalgic gait pattern

›Shortened stance phase on affected side

›Externally rotated gait (compensatory to avoid tibial eminence impingement)

›Weight-bearing tolerance

›Full vs. partial vs. non-weight-bearing

›Pain provocation with loading

Knee joint examination

›Effusion assessment

›Ballottement test

›Presence is a risk factor for lesion instability

›Large effusion suggests unstable lesion or loose body

›Sweep test (small effusion detection)

›Medial to lateral sweep elicits fluid wave

›Range of motion

›Active and passive flexion and extension

›Loss of motion is a risk factor for instability

›Terminal extension loss suggests anterior impingement

›Crepitus with range of motion

›Coarse crepitus suggests fragment or loose body

›Palpation

›Medial femoral condyle tenderness

›Best assessed with knee flexed at 90 degrees

›Classic location for OCD lesion

›Joint line palpation

›Medial and lateral joint line for meniscal distinction

04Differential Diagnosis/ddx63

Life-threatening and urgent diagnoses

›Diagnoses not to miss

›Septic arthritis

›ICD-10: M00.06 (knee)

›Fever, effusion, elevated ESR/CRP

›Joint aspiration mandatory if suspected

›Osteomyelitis

›ICD-10: M86.16

›Periosteal reaction and bone destruction on imaging

›Systemic signs of infection

›Bone tumor

›ICD-10: D16.2 (benign), C40.2 (malignant)

›Night pain, rest pain, soft tissue mass

›Aggressive periosteal reaction on radiograph

Traumatic and mechanical diagnoses

›Acute traumatic conditions

›ACL injury

›ICD-10: S83.501

›Acute hemarthrosis following acute traumatic mechanism

›Positive Lachman and anterior drawer

›Meniscal tear

›ICD-10: M23.20

›Joint line tenderness, McMurray positive

›MRI distinguishes from OCD

›Osteochondral fracture

›ICD-10: S83.00

›Acute traumatic mechanism distinguishes from insidious OCD

›Displaced fragment visible on radiograph

05Laboratory Tests/lt42

Infection and inflammation markers

›Laboratory exclusion of infection and inflammation

›Complete blood count

›Leukocytosis suggests infection or inflammatory arthritis

›Thrombocytosis in chronic inflammatory states

›Indication: fever or concern for septic arthritis

›Erythrocyte sedimentation rate

›Elevated in infection, inflammatory arthritis, and malignancy

›Normal in isolated OCD

›C-reactive protein

›More sensitive than ESR for acute infection

›Levels >10 mg/l warrant further evaluation

›Normal in isolated OCD

Synovial fluid analysis

›Joint aspiration fluid analysis

›Indications for aspiration

›Tense painful effusion

›Concern for septic arthritis

›Diagnostic uncertainty

›Fluid interpretation

›WBC >50,000 cells/mm3 suggests septic arthritis

›Bloody fluid suggests unstable OCD fragment or osteochondral fracture

›Gram stain and culture if infection suspected

Metabolic and nutritional labs

›Bone health assessment

›Vitamin D (25-hydroxyvitamin D)

›Consider in patients with risk factors for deficiency

›Deficiency may impair bone healing in OCD

06Diagnostic Tests/dt95

Scoring Systems

›OCD lesion staging and classification systems

›Hefti MRI classification (5 grades)

›Grade I: thickening of articular cartilage, low-signal changes

›Grade II: articular cartilage breached, low-signal rim behind fragment

›Grade III: high-signal changes behind fragment (fluid tracking)

›Grade IV: fluid-filled gap, cysts behind fragment

›Grade V: loose body

›Moderate inter-rater reliability

›Nelson classification (4 groups)

›Group I: normal bone, intact cartilage

›Group II: partial lesion, stable

›Group III: complete lesion but attached

›Group IV: complete, detached (loose body)

›Novel 3-group MRI classification

›Simpler approach with near-perfect intrarater agreement

›Group A: stable; Group B: at risk; Group C: unstable

›De Smet MRI criteria for instability

›High T2 signal rim >5 mm around fragment

›Cystic changes beneath fragment

›Cartilage fracture line at junction

›Fluid-filled defect

MRI

›MRI indications and protocol

›Primary indications

›Radiograph positive or equivocal for OCD

›Clinical suspicion despite normal radiograph

›Lesion characterization for treatment planning

›MRI sequences and findings

›Proton density fat-saturated or T2-weighted sequences

›T1 for bone marrow signal and fragment characteristics

›High T2 signal rim indicates fluid tracking — key instability sign

›Subchondral bone edema pattern

›Stability assessment on MRI

›Pooled sensitivity 92% for instability

›Pooled specificity 85% (lower in juvenile OCD at ~68%)

›Overlying cartilage alteration has highest discriminative performance (AUC 0.92)

›MRI instability signs

›Loss of articular cartilage cap

›Cystic changes beneath the fragment

›High T2 signal rim deep to OCD lesion

›Subchondral bone disruption

›Osteochondral defect (fragment displaced or absent)

›MRI limitations

›Lower specificity for instability in juvenile OCD (~68%)

›Cannot replace arthroscopy for definitive stability assessment

›Interpretation requires musculoskeletal radiologist expertise

CT

›CT indications and role

›CT is not first-line for OCD diagnosis

›Inferior to MRI for cartilage and soft tissue assessment

›Higher radiation dose than radiograph without added soft tissue benefit

›CT indications in OCD

›Postoperative healing assessment

›Evaluate bone graft incorporation

›Assess fragment fixation hardware

›Complex lesion anatomy planning

›Preoperative 3D assessment of large lesions

›Lesion volume calculation for graft sizing

›CT arthrography

›Alternative when MRI is contraindicated

›Evaluates articular cartilage integrity

›Less available than MRI; requires intra-articular injection

Ultrasound

›Ultrasound role in OCD

›Standard knee OCD assessment

›Not recommended as primary imaging modality for knee OCD

›Inferior to MRI for lesion characterization and stability

›Emerging role for elbow OCD

›Useful for screening in overhead throwing athletes

›Assesses cartilage surface and effusion at capitellum

›Not yet standard of care

›Joint effusion assessment

›Point-of-care ultrasound to detect knee effusion

›Guides aspiration if clinically indicated

›Evaluates for loose bodies in the joint

Plain radiography

›Radiograph protocol and findings

›Required views

›Weight-bearing anteroposterior view

›Tunnel (notch) view — critical for medial femoral condyle lesion

›Lateral view

›Axial patellar view (Merchant/sunrise at 30–45 degrees flexion)

›Radiographic findings

›Focal subchondral lucency at lesion site

›Sclerotic rim around the fragment

›Fragment separation or loose body

›Physeal status assessment

›Bilateral radiographs

›Recommended given ~33% bilateral incidence

›Contralateral asymptomatic lesions identified in significant proportion

Arthroscopy

›Arthroscopy as diagnostic and therapeutic tool

›Role in OCD management

›Gold standard for definitive stability assessment

›Direct visualization of articular cartilage surface

›Probing of lesion margins during procedure

›Indications for diagnostic arthroscopy

›Inconclusive MRI stability assessment

›Concurrent surgical intervention planned

›Loose body retrieval or fragment fixation

07Disposition/dispo36

Discharge criteria

›Safe discharge parameters

›Clinical eligibility for outpatient management

›No mechanical symptoms (locking, catching, giving way)

›Able to bear weight with manageable pain

›No signs of septic arthritis

›No displaced loose body on imaging

›Outpatient follow-up arranged

›Orthopedic sports medicine or pediatric orthopedics referral

›All confirmed OCD cases require orthopedic referral

›Timing: within 2–4 weeks for stable lesions

Urgent orthopedic referral

›Same-day or next-day consultation triggers

›Mechanical symptoms at presentation

›True locking suggesting loose body

›Inability to extend the knee fully

›Large effusion suggesting unstable lesion

›Hemarthrosis on aspiration

›Acute onset in context of known OCD

›Suspected acute fragment displacement

›Loss of motion compared with prior

›Visible loose body on radiograph

Admission criteria

›Indications for hospital admission

›Perioperative setting

›Complex surgical cases requiring observation

›Rarely required for OCD specifically

›Exclusion of septic arthritis

08Treatment/t107

Activity restriction and conservative management

›Conservative management for stable lesions with open physes

›Activity restriction protocol

›Cessation of impact and pivoting sports

›Duration: 3–6 months

›Protected weight-bearing with or without crutches

›Bracing

›Unloader brace may reduce medial compartment stress

›Hinged knee brace for comfort and support

›Not mandatory but adjunctive

›Success rate

›Approximately 50–65% in juvenile OCD

›Lower in adult OCD with closed physes

Physical therapy

›Rehabilitation program

›Goals during activity restriction

›Maintain range of motion

›Prevent quadriceps atrophy

›Avoid aggravating loading activities

›Permitted exercises

›Straight leg raises and isometric quadriceps strengthening

›Non-impact aerobic conditioning (swimming, cycling)

›Proprioception and balance training as tolerated

›Progression criteria

›Symptom-free with activity restriction

›Radiographic evidence of healing before impact reintroduction

Pharmacologic management

›Analgesia and anti-inflammatory therapy

›NSAIDs — first-line for pain and inflammation

›Ibuprofen 400–600 mg orally every 6–8 hours with food

›Maximum 2400 mg/day

›Duration limited to symptomatic phase

›Naproxen 250–500 mg orally every 12 hours

›Maximum 1000 mg/day

›Renal monitoring with prolonged use

›Acetaminophen — alternative analgesic

›500–1000 mg orally every 6–8 hours

›Maximum 4000 mg/day (2000 mg/day in hepatic impairment)

›Safe concurrent use with NSAIDs if both needed

›Corticosteroid injections — avoid

›May impair cartilage and subchondral bone healing

›Contraindicated in OCD management

›Nutritional supplementation

›Vitamin D if deficient — target 25-hydroxyvitamin D >50 nmol/l

›Calcium 1000–1300 mg/day in adolescents with inadequate intake

›Weight management counseling for obese patients

Surgical management — indications

›Indications for surgical intervention

›Failed conservative treatment

›Persistent symptoms after 3–6 months of conservative management

›Class I evidence for surgical intervention in this setting

›Unstable lesion at presentation

›MRI or arthroscopic instability confirmed

›Articular surface breach on imaging

›Closing physes with persistent symptoms

›Reduced healing potential of conservative management

›Large lesion or atypical location

›Weight-bearing zone lesion

›Lesion diameter >1.5 cm

›Mechanical symptoms at presentation

›Locking, catching, or true giving way

Surgical procedures — stable failed conservative

›Drilling procedures for stable lesions

›Retroarticular drilling

›Avoids articular cartilage violation

›Creates vascular channels to enhance healing

›Fluoroscopic or arthroscopic guidance required

›Transarticular drilling

›Through articular cartilage surface to subchondral bone

›Stimulates healing response in subchondral bone

›Preferred when cartilage surface integrity is maintained

›Post-procedure protocol

›Protected weight-bearing 4–6 weeks

›Return to sport 4–6 months postoperatively

Surgical procedures — unstable repairable lesions

›Fragment fixation for unstable but repairable lesions

›Drilling combined with fixation

›Bioabsorbable screws — avoid hardware removal

›Metal compression screws — stronger fixation for larger fragments

›Bone grafting for large defects under fragment

›Success rates for fixation

›67–100% success in appropriate candidates

›Higher success in juvenile OCD with open physes

›Post-fixation protocol

›Non-weight-bearing 6–8 weeks

›Return to sport 6–12 months postoperatively

›Hardware removal if symptomatic (metal screws)

Surgical procedures — non-repairable lesions

›Cartilage restoration procedures

›Autologous chondrocyte implantation (ACI)

›Two-stage procedure: harvest then implantation

›Best for larger defects >2 cm2

›Staged with 6–8 weeks between procedures

›Osteochondral autograft transfer (OATS/mosaicplasty)

›Harvest from non-weight-bearing zone

›Best for smaller defects <2–3 cm2

›Single-stage procedure

›Osteochondral allograft transplantation

›Fresh allograft preferred for cell viability

›Large defects >3 cm2 or failed prior procedures

›Availability dependent on tissue bank

›Marrow stimulation (microfracture)

›Indicated for small defects <2 cm2

›Poor results for large weight-bearing lesions

›Inferior fibrocartilage fill compared with other techniques

Return to sport

›Return-to-sport criteria and timeline

›Conservative management

›Symptom-free with full range of motion

›Radiographic healing confirmed at 3–6 months

›Graduated return to activity supervised by physiotherapy

›Post-surgical return

›Drilling procedures: 4–6 months

›Fixation and grafting: 6–12+ months

›Overall return-to-sport rates >85% in skeletally immature patients

09Special Populations/sp59

Pregnancy

›OCD in pregnancy

›Clinical considerations

›OCD predominantly affects adolescents; pregnancy coincidence uncommon

›MRI preferred over radiograph for lesion characterization in pregnancy

›MRI without gadolinium in first trimester preferred

›Pharmacologic considerations in pregnancy

›NSAIDs contraindicated after 20 weeks gestation

›Risk of premature ductus arteriosus closure

›Risk of oligohydramnios

›Acetaminophen preferred analgesic in pregnancy

›Standard dosing 500–1000 mg every 6–8 hours

›Corticosteroid injections — avoid given OCD-specific contraindication

›Surgical timing in pregnancy

›Elective orthopedic surgery deferred to postpartum when possible

›If surgical intervention required, second trimester preferred

›Regional anesthesia preferred over general anesthesia

Geriatric

›OCD in older adults

›Clinical presentation differences

›Adult OCD presents with closed physes — poorer prognosis

›Greater propensity to instability and premature osteoarthritis

›Overlap with AVN and degenerative joint disease

›Pharmacologic considerations

›NSAIDs with increased caution in older adults

›Renal function impairment risk

›Cardiovascular risk with prolonged use

›Gastroprotection with proton pump inhibitor if NSAIDs used

10Background/b71

Epidemiology

›Incidence and prevalence data

›Overall annual incidence

›6–29 per 100,000 population

›Incidence appears to be increasing

›Likely related to earlier and more competitive sports participation

›Age and sex distribution

›Most commonly affects preadolescent and adolescent athletes aged 10–20 years

›Peak incidence: males 11–15 years

›Male-to-female incidence ratio 2–4:1

›Black race associated with higher odds of OCD

›Most commonly affected joints

›Knee: most common site (~75% of all OCD)

›Elbow (capitellum): second most common

›Ankle (talus): third most common

›Bilateral knee involvement in approximately one-third of cases

›Sports association

›Basketball most common sport in males

›Soccer most common sport in females

›Overhead throwing sports for elbow OCD

›Natural history

›May lead to premature osteoarthritis if untreated

›Complications include chronic pain and functional disability

›Return-to-sport >85% in skeletally immature patients with appropriate management

Pathophysiology

›Etiology and pathologic mechanisms

›Multifactorial etiology

›No single definitive cause identified

›Repetitive microtrauma and mechanical overload primary hypothesis

›Ischemic injury to subchondral bone secondary to repetitive stress

›Vascular hypothesis

›Disruption of end-arterial blood supply to subchondral bone

›Results in focal avascular necrosis of subchondral bone

›Overlying articular cartilage receives nutrition via synovial fluid

›Mechanical overload hypothesis

›Repetitive compressive and shear forces exceed bone remodeling capacity

›Subchondral bone fatigue failure

›Associated with limb malalignment and obesity

›Genetic predisposition

›Familial clustering observed

›Genetic factors theorized but not fully characterized

›Association with skeletal dysplasias in some cases

›Lesion progression stages

›Early: subchondral bone edema and stress reaction

›Intermediate: focal subchondral bone necrosis with intact cartilage

›Advanced: articular cartilage disruption and fragment instability

›Late: fragment displacement and loose body formation

›Site-specific anatomy

›Lateral aspect of medial femoral condyle: classic and most common knee location

›Lateral femoral condyle: less common

›Capitellum: vascular anatomy predisposes to OCD in throwers

Therapeutic Considerations

›Evidence base for treatment decisions

›Conservative management evidence

›AAOS 2023 guideline: activity restriction recommended for stable juvenile OCD

›50–65% healing rate with conservative management in juvenile OCD

›Open physes most important predictor of conservative success

›Surgical management evidence

›Drilling: effective for stable lesions failing conservative management

›Fragment fixation: 67–100% success for unstable repairable lesions

›Cartilage restoration: osteochondral procedures for non-repairable defects

›Prognostic factors for healing

›Favorable: age <12 years, open physes, small lesion, non-weight-bearing location

›Unfavorable: closed physes, large lesion, weight-bearing zone, mechanical symptoms

›Smoking predicts instability in older adolescents

›ICD-10 coding

›M93.20 — osteochondritis dissecans, unspecified site

›M93.21 — osteochondritis dissecans, shoulder region

›M93.26 — osteochondritis dissecans, knee

›M93.27 — osteochondritis dissecans, ankle and joints of foot

›Guideline recommendations

›AAOS Evidence-Based Clinical Practice Guideline 2023 (rapid update)

›American Medical Society for Sports Medicine position statement on overuse injuries

›Research in Osteochondritis Dissecans of the Knee (ROCK) consortium data

11Patient Discharge Instructions/pdi34

copy discharge instructions

›Osteochondritis Dissecans — Discharge Instructions

›What is osteochondritis dissecans

›A condition where a piece of bone and cartilage inside the knee joint loses its blood supply

›Can become loose and cause pain, locking, or instability of the knee

›Most common in young athletes aged 10–20 years

›Usually heals with activity rest and time if caught early

›Activity restrictions

›Stop all impact and pivoting sports immediately

›No running, jumping, basketball, soccer, or similar activities

›Walking for daily activities is usually permitted

›Follow your orthopedic surgeon's specific instructions

›Pain management at home

›Ibuprofen or naproxen as directed for pain and swelling

›Take with food to protect the stomach

›Acetaminophen is a safe alternative if ibuprofen causes stomach upset

›Ice the knee for 15–20 minutes several times per day for swelling

›Medications prescribed

›Take all medications as prescribed

›Do not use cortisone or steroid injections in the knee without discussing with your orthopedic surgeon

›Follow-up appointments

›Orthopedic sports medicine or pediatric orthopedics within 2–4 weeks

›Repeat X-ray or MRI at 3–6 months to check healing

›Do not return to sport until your doctor confirms healing on imaging

›Return to the emergency department immediately for

›Knee that locks up and cannot be straightened

›Sudden severe increase in pain or swelling

›Inability to bear any weight on the leg

12References/r42

Guidelines and key sources

›Primary clinical practice guidelines

›American Academy of Orthopaedic Surgeons (AAOS) 2023

›Diagnosis and Treatment of Osteochondritis Dissecans: Evidence-Based Clinical Practice Guideline (Rapid Update)

›https://www.aaos.org/globalassets/quality-and-practice-resources/osteochondritis-dissecans/osteochondritis-dissecans-rapid-update-2023.pdf

›American Medical Society for Sports Medicine (AMSSM)

›Position statement on overuse injuries and burnout in youth sports

›DiFiori JP et al. Clinical Journal of Sport Medicine 2014

›Research in Osteochondritis Dissecans of the Knee (ROCK) Consortium

›Nissen CW et al. American Journal of Sports Medicine 2022

›Prospective cohort descriptive epidemiology

Systematic reviews and key studies

›Landmark studies and systematic reviews

›Mitchell BC, Shea KG, Ganley TJ et al.

›Juvenile Knee Osteochondritis Dissecans. Arthroscopy 2025

›PMID: 41136105

›Chau MM, Klimstra MA, Wise KL et al.

›OCD: Current Understanding of Epidemiology, Etiology, Management, and Outcomes

›Journal of Bone and Joint Surgery 2021. PMID: 34109940

›Nammour MA, Mauro CS, Bradley JP, Arner JW

›OCD Lesions of the Knee: Evidence-Based Treatment

›JAAOS 2024. PMID: 38295387

›Hu H, Zhang C, Chen J et al.

›Clinical Value of MRI in Assessing Stability of OCD Lesions: Systematic Review and Meta-Analysis

›AJR 2019. PMID: 30995094

›Pooled sensitivity 92%, specificity 85%

›Waters T, Gowd AK, Waterman BR

›Management of Symptomatic OCD of the Knee. Arthroscopy 2020

Evidence & Review