Osteochondritis Dissecans
Summary
Osteochondritis dissecans (OCD) is a condition affecting the subchondral bone, leading to separation of an osteochondral fragment from the underlying bone. The knee is most commonly affected (75%), particularly the lateral aspect of the medial femoral condyle. OCD has a juvenile form (open physes, excellent prognosis) and an adult form (closed physes, poorer prognosis). Treatment depends on lesion stability — stable lesions are managed conservatively with activity modification, while unstable lesions with loose bodies require arthroscopic intervention.
Key Facts
- Definition: Localised disorder of subchondral bone causing osteochondral separation
- Prevalence: 15-29 per 100,000 in general population; higher in young athletes
- Location: Knee 75% (medial femoral condyle most common), elbow, ankle
- Classic Site: Lateral aspect of medial femoral condyle (LAME mnemonic — actually posterolateral)
- Key Factor: Skeletal maturity — juvenile OCD (open physes) has excellent prognosis
- Treatment: Conservative if stable; surgical if unstable or loose body
Clinical Pearls
"LAME" but Lateral: Classic teaching is "Lateral Aspect of Medial Epicondyle" but this is inaccurate — the lesion is on the posterolateral aspect of the medial femoral condyle. Use MRI to precisely locate.
Wilson's Test: Pain on internal rotation during knee extension (30→60°), relieved by external rotation. Specific but not sensitive — negative test doesn't exclude OCD.
Physeal Status is Key: Check skeletal maturity with X-ray. Open physes = juvenile OCD with >90% healing potential. Closed physes = adult OCD with higher surgical rates.
Why This Matters Clinically
OCD is an important cause of knee pain in adolescent athletes. Early recognition and appropriate activity modification can allow healing in juvenile OCD. Missed or poorly managed OCD can progress to loose body formation, locking, and early-onset osteoarthritis.
Incidence & Prevalence
- Incidence: 15-29 per 100,000 in general population
- Higher in athletes: Particularly sports involving running, jumping, pivoting
- Age: Juvenile OCD 10-15 years; Adult OCD >20 years
- Trend: Increasing due to year-round sports participation
Demographics
| Factor | Details |
|---|---|
| Age | Juvenile: 10-15 years; Adult: >20 years |
| Sex | Male:Female 2-3:1 |
| Activity | Higher in athletes (soccer, basketball, gymnastics) |
| Location | Knee 75%, Elbow 5%, Ankle 4%, other sites |
Risk Factors
Non-Modifiable:
- Male sex
- Genetic predisposition (bilateral cases suggest genetic component)
- Family history
- Growing skeleton (physes still open)
Modifiable:
| Risk Factor | Notes |
|---|---|
| Repetitive high-impact sports | Soccer, basketball, gymnastics |
| Year-round sports specialisation | Insufficient recovery time |
| Low vitamin D | May impair bone healing |
Mechanism
Step 1: Initiating Factor
- Repetitive microtrauma (most common theory)
- Localised ischaemia
- Possible genetic predisposition
Step 2: Subchondral Bone Weakening
- Stress to subchondral bone exceeds repair capacity
- Focal osteonecrosis develops
- Overlying cartilage initially intact
Step 3: Fragment Formation
- Osteochondral fragment begins to separate
- May remain in situ (stable) or become partially/completely detached
- Cartilage may remain intact (stable) or breach (unstable)
Step 4: Loose Body (If Unstable)
- Complete separation creates loose body
- Mechanical symptoms (locking, catching)
- Exposed subchondral bone leads to OA
Classification (Stability)
MRI Classification (Mesgarzadeh Modified):
| Grade | Description | Stability | Management |
|---|---|---|---|
| I | Subchondral signal change only | Stable | Conservative |
| II | Partially detached, intact cartilage | ? Stable | Conservative ± surgery |
| III | Completely detached, in situ | Unstable | Surgery |
| IV | Loose body | Unstable | Surgery |
Arthroscopic Classification:
| Stage | Finding | Stability |
|---|---|---|
| I | Softening of cartilage | Stable |
| II | Partial detachment | ? Stable |
| III | Complete detachment, in crater | Unstable |
| IV | Loose body, empty crater | Unstable |
Anatomical Considerations
- Medial Femoral Condyle (70%): Lateral aspect — classic site
- Lateral Femoral Condyle (15-20%): Poorer prognosis
- Patella (5-10%): Characteristic location
- Elbow: Capitellum (Little League elbow)
- Ankle: Talar dome
Symptoms
Typical Presentation:
Atypical Presentations:
Signs
Red Flags
[!CAUTION] Red Flags — Suggest unstable lesion requiring intervention:
- True mechanical locking (knee stuck)
- Sudden giving way during activity
- Large recurrent effusions
- Palpable loose body
- Rapid progression of symptoms
Structured Approach
General:
- Observe gait (antalgic pattern)
- Assess quadriceps bulk (compare sides)
- Check ROM of both knees
Specific Examination:
- Palpate for effusion (sweep test, patella tap)
- Localise tenderness (medial vs lateral condyle)
- Check ROM (block suggests loose body)
- Special tests for OCD
Special Tests
| Test | Technique | Positive Finding | Significance |
|---|---|---|---|
| Wilson's Test | Knee in extension from 90°, internally rotate tibia; extend to 30° | Pain at 30° extension, relieved by external rotation | Suggests medial condyle OCD (specific, not sensitive) |
| Sweep Test | Milk fluid from lateral to medial | Fluid bulge on medial side | Small effusion |
| Patella Tap | Push patella onto condyles | Ballottement | Moderate effusion |
| McMurray's | Rotation + valgus/varus during flexion | Click, pain | May have meniscal injury too |
First-Line (Bedside)
- Clinical examination
- Compare to contralateral knee
Laboratory Tests
| Test | Expected Finding | Purpose |
|---|---|---|
| Usually not required | — | Diagnosis is clinical and radiological |
| Vitamin D | Consider checking if deficient | May aid healing |
Imaging
| Modality | Findings | Indication |
|---|---|---|
| X-ray | AP, Lateral, Tunnel (notch) view | First-line; shows lesion location and size |
| Tunnel View | Best visualises posterior condyle lesion | Essential for OCD diagnosis |
| MRI | Lesion stability, cartilage status, oedema | Staging and treatment planning |
| MRI Assessment | High T2 signal behind fragment = unstable | Key stability indicator |
Diagnostic Criteria
Diagnosis confirmed by:
- Clinical suspicion (activity-related knee pain in adolescent/young adult)
- X-ray showing radiolucent lesion with sclerotic margin
- MRI for staging and stability assessment
Management Algorithm
OCD MANAGEMENT
↓
┌─────────────────────────────────────────────────────┐
│ JUVENILE OCD (Physes Open) │
│ │
│ STABLE LESION: │
│ • Strict activity modification (no sport) │
│ • Protected weight-bearing (crutches if needed) │
│ • Duration: 3-6 months │
│ • Repeat MRI at 3-6 months │
│ • Healing rate: >90% │
│ │
│ UNSTABLE LESION: │
│ • Arthroscopic drilling (retrograde or antegrade) │
│ • Fragment fixation if large │
└─────────────────────────────────────────────────────┘
↓
┌─────────────────────────────────────────────────────┐
│ ADULT OCD (Physes Closed) │
│ │
│ STABLE LESION: │
│ • Trial of conservative (3-6 months) │
│ • Lower healing rate than juvenile │
│ • Consider early surgery if athlete │
│ │
│ UNSTABLE LESION / LOOSE BODY: │
│ • Arthroscopic intervention │
│ │
│ Surgical Options (Size-Dependent): │
│ • Small (<1cm²): Debridement + Microfracture │
│ • Medium (1-4cm²): OATS │
│ • Large (>4cm²): ACI or MACI │
│ • Fragment viable: Internal fixation │
└─────────────────────────────────────────────────────┘
Conservative Management (Juvenile Stable)
- Activity restriction: No running, jumping, pivoting sports
- Weight-bearing: Protected with crutches if symptomatic
- Duration: 3-6 months minimum
- Monitoring: Clinical review every 6-8 weeks; repeat MRI at 3-6 months
- Expected outcome: >90% healing in juvenile stable lesions
Surgical Management
Indications:
- Unstable lesion (all ages)
- Loose body
- Failed conservative management
- Symptomatic adult OCD
Procedures:
| Procedure | Description | Indication |
|---|---|---|
| Drilling | Subchondral drilling to promote healing | Stable lesion not responding |
| Internal Fixation | Bioabsorbable screws/darts | Unstable but viable fragment |
| Debridement + Microfracture | Remove loose fragment, stimulate fibrocartilage | Small defects (<1cm²) |
| OATS | Osteochondral autograft transfer | Medium defects (1-4cm²) |
| ACI/MACI | Autologous chondrocyte implantation | Large defects (>4cm²) |
Disposition
- Outpatient: All stable lesions
- Specialist referral: All confirmed OCD for ongoing management
- Follow-up: Regular clinical and radiological monitoring
Immediate (Surgical)
| Complication | Incidence | Presentation | Management |
|---|---|---|---|
| Haemarthrosis | Uncommon | Swelling, stiffness | Ice, elevation, aspiration if large |
| Infection | Rare | Pain, erythema, fever | Antibiotics, washout |
Early (Weeks-Months)
- Graft failure: OATS/ACI — may need revision
- Stiffness: Arthrofibrosis — physio, possible MUA
- Non-healing: Persistent lesion despite treatment
Late (Years)
- Osteoarthritis: Major long-term concern — earlier onset
- Recurrence: Especially if returned to sport too early
- Chronic pain: May persist despite treatment
- Contralateral OCD: 20-30% bilateral — monitor
Natural History
The prognosis depends heavily on skeletal maturity and lesion stability. Juvenile OCD with stable lesions has excellent prognosis with conservative management (>90% healing). Adult OCD has poorer outcomes, with higher rates of surgery and earlier osteoarthritis.
Outcomes with Treatment
| Variable | Outcome |
|---|---|
| Juvenile stable (conservative) | >90% healing |
| Adult stable (conservative) | 50-60% healing |
| Microfracture | Good short-term; may deteriorate long-term |
| OATS | 80-90% good outcome (medium defects) |
| ACI/MACI | 75-85% good outcome (large defects) |
Prognostic Factors
Good Prognosis:
- Juvenile OCD (open physes)
- Stable lesion
- Medial condyle location
- Small lesion size (<2cm²)
- Compliance with activity restriction
Poor Prognosis:
- Adult OCD (closed physes)
- Unstable/loose body
- Lateral condyle location
- Large lesion
- Return to sport before healing confirmed
Key Guidelines
-
AAOS Appropriate Use Criteria (2017) — Provides guidance on when surgery vs. conservative management is appropriate based on lesion characteristics and skeletal maturity.
-
ICRS Guidelines — International Cartilage Regeneration & Joint Preservation Society guidance on cartilage repair techniques.
Landmark Studies
Kocher et al. (2001) — Natural history study
- Long-term follow-up of juvenile OCD
- Key finding: Majority heal with activity modification if stable
- Clinical Impact: Supports conservative first approach in juveniles
Carey et al. (2006) — Predictors of healing
- Identified factors predicting lesion healing
- Key finding: Open physes strongest predictor of healing
- Clinical Impact: Emphasises importance of skeletal maturity assessment
Gudas et al. (2005) — OATS vs microfracture
- Randomised controlled trial
- Key finding: Superior outcomes with OATS at 3 years
- Clinical Impact: OATS preferred for medium-sized lesions
Evidence Strength
| Intervention | Level | Key Evidence |
|---|---|---|
| Conservative (juvenile stable) | 2a | Systematic reviews, cohorts |
| Drilling | 2b | Case series |
| OATS | 1b | RCTs |
| Microfracture | 2a | Systematic reviews |
| ACI/MACI | 1b | RCTs for large defects |
What is Osteochondritis Dissecans?
Osteochondritis dissecans (OCD) is a condition where a piece of bone and the cartilage covering it in a joint start to separate from the rest of the bone. It most commonly affects the knee, usually in teenagers and young adults who are active in sports. The area of bone doesn't get enough blood supply and starts to weaken.
Why does it matter?
If not treated properly, the piece of bone and cartilage can break off completely and become a "loose body" floating in the joint. This causes the knee to lock suddenly or give way. Even more importantly, losing this cartilage puts you at higher risk of developing arthritis in that knee later in life.
How is it treated?
-
If you're still growing (open growth plates): Most cases heal on their own if you stop the activities that stress the knee. This means stopping sports for 3-6 months. It's hard, but it works more than 90% of the time.
-
If you're fully grown: Healing without surgery is less likely. Your doctor may recommend surgery to fix or replace the damaged area.
-
If there's a loose piece: Surgery is needed to either fix the piece back in place or remove it and repair the area it came from.
What to expect
- Treatment takes 3-6 months minimum
- You'll need to stop sports activities during this time
- Regular follow-up X-rays or MRI scans to monitor healing
- Full recovery: 6-12 months
- You can usually return to sports once healed
When to seek help
See your doctor if:
- Your knee suddenly locks and won't move
- The knee gives way unexpectedly
- Pain is getting worse despite rest
- You notice a lot of swelling after activity
Primary Guidelines
- American Academy of Orthopaedic Surgeons. Appropriate Use Criteria for the Treatment of Osteochondritis Dissecans. 2017.
Key Trials
-
Kocher MS, Micheli LJ, Yaniv M, et al. Functional and radiographic outcome of juvenile osteochondritis dissecans of the knee treated with transarticular arthroscopic drilling. Am J Sports Med. 2001;29(5):562-566. PMID: 11573912
-
Carey JL, Wall EJ, Grimm NL, et al. Novel arthroscopic classification of osteochondritis dissecans of the knee: a multicenter reliability study. Am J Sports Med. 2016;44(7):1694-1698. PMID: 27166288
-
Gudas R, Kalesinskas RJ, Kimtys V, et al. A prospective randomized clinical study of mosaic osteochondral autologous transplantation versus microfracture for the treatment of osteochondral defects in the knee joint in young athletes. Arthroscopy. 2005;21(9):1066-1075. PMID: 16171631
Further Resources
- International Cartilage Regeneration & Joint Preservation Society (ICRS)
- Radiopaedia: OCD imaging examples
Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate guidelines and specialists for patient care.