Osteochondrosis dissecans (OCD) of the knee

What is osteochondrosis dissecans?

Osteochondrosis dissecans (OCD) describes a localized circulatory and structural disorder of the subchondral bone. The overlying articular cartilage may appear intact for a long time, but loses its stability as it progresses. In late stages, an osteochondral fragment may partially or completely detach; occasionally it becomes a free joint body (“joint mouse”).

Children, teenagers and young adults who are active in sports are often affected. There is a juvenile form (open growth plates) which usually has a better healing tendency and an adult form (closed growth plates) which more often requires surgical therapy. Men are slightly overrepresented, but both genders can be affected.

• Typical location: medial femoral condyle (inside), rarely lateral condyle or trochlea
• Side comparison: often one-sided, in a few cases bilateral
• Synonyms/Related: osteochondral lesion, osteochondral fracture (not identical), free articular bodies in the late stage

Symptoms and warning signs

The symptoms often begin gradually. After exercise or prolonged stress, the knee hurts and swells. The symptoms improve with rest, but return with exertion. Advanced stages may cause pinching sensations or blockages.

• Stress-dependent pain on the inside of the knee
• Swelling/effusion (irritable effusion), feeling of warmth
• Start-up pain, sometimes pain at rest or at night
• Feeling of buckling, entrapment, blockages
• Restriction of movement, v. a. when bending

Warning signs that should be clarified by a doctor: recurring swelling, blockages, persistent pain over several weeks, acute deterioration after twisting trauma.

Causes and risk factors

The cause is multifactorial. Repeated microtraumas and high repetitive stress (e.g. jumps, changes of direction) are considered beneficial. Temporary circulatory impairment of the subchondral bone, individual anatomical factors and increased susceptibility during growth also play a role. Rarely, there are concomitant illnesses or biomechanical peculiarities.

• High sporting load (football, athletics, basketball, etc.)
• Axial deviations (e.g. bowlegs/varus) and instabilities
• Previous trauma or osteochondral contusions
• Rapid growth spurt in youth
• Possible genetic/constitutional factors (rare, not confirmed)

Important: Not every intense sporting activity leads to OCD. Individual resilience, regeneration and biomechanical conditions are crucial. Adjusting your training early can avoid overload peaks.

Diagnostics in orthopedics

Diagnostics combines anamnesis, physical examination and imaging. The aim is to assess the location, size and stability of the lesion as well as possible accompanying factors (axial relationships, ligament stability, meniscus/cartilage status).

• Clinical: tenderness over the affected condyle, pain provocation during flexion/rotation; occasionally positive Wilson sign
• X-ray: AP, lateral and tunnel image (notch/shot image) for detection and follow-up
• MRI: Assessment of signs of stability (edema, cystic changes, fluid margin), cartilage involvement and fragment status
• CT (selective): detailed bony imaging if required for surgical planning
• Gait analysis/axis assessment: Determination of varus/valgus, leg axis, foot position

The stage and stability assessment in MRI has direct consequences for the treatment decision (conservative vs. surgical). If there are blockages or there is evidence of free joint bodies, a prompt clarification is necessary.

Stages and stability

The decisive factor in therapy is the distinction between stable and unstable lesions and between juvenile and adult forms. A simplified diagram helps with classification:

Juvenile stable lesions heal more frequently with relief and activity adjustment. Unstable or adult lesions often require surgical measures to protect cartilage and bone in the long term.

Conservative therapy: first calm the joint

For stable, especially juvenile OCD lesions, non-surgical treatment has priority. It aims to relieve pressure, reduce pain and biologically heal the subchondral bone. Regular progress checks are important in order to make adjustments in a timely manner.

• Activity adjustment and break from sports (usually several months, depending on the stage)
• Partial weight bearing with forearm crutches according to medical instructions
• Physiotherapy: pain-adapted mobilization, strengthening of quadriceps/hamstring muscles, hip and trunk stability, neuromuscular control
• Axle and shoe insole care with biomechanical relevance (e.g. varus relief)
• Short-term anti-inflammatory measures (cooling, medication if necessary), no long-term use without indication
• Gradual increase in stress depending on symptoms and progression in imaging

Additional biological procedures (e.g. shock waves, injections) are discussed in individual cases. The evidence is heterogeneous; An application should be considered individually and explained transparently. The focus remains on rest, relief and targeted development.

Surgical options: appropriate to the indication and gentle on the tissue

A surgical procedure is an option for unstable lesions, freely displaced fragments, persistent symptoms despite conservative therapy or for adult OCD with little tendency to heal. The choice of procedure depends on age, fragment size, location, stability and cartilage status.

• Retrograde drilling (drilling): For stable, predominantly juvenile lesions. Aim: Revascularization and biological healing of the subchondral bone while preserving the cartilage surface.
• Refixation of the fragment: Arthroscopic or mini-open with absorbable pins/screws. Often combined with spongiosaplasty to fill the bone.
• Osteochondral cylinder transplantation (OATS/mosaicplasty): For a circumscribed defect that cannot be reconstructed. Removal of cylindrical bone-cartilage transplants from less stressed areas.
• Bone augmentation plus cartilage reconstruction: For larger defects, two-stage procedures may be necessary (e.g. autologous chondrocyte transplantation, matrix-associated), always with attention to subchondral bone healing.
• Removal of free joint bodies and smoothing of defects: relief of symptoms in smaller, non-reconstructable fragments; if necessary, additional biological processes.

The aim of all procedures is the best possible restoration of a stable joint surface and protection against progressive cartilage damage. We decide which option makes sense in each individual case after detailed consultation, imaging and a joint definition of goals.

Follow-up treatment and rehabilitation

Rehabilitation is crucial to success. It is individually adapted to the procedure and stage. Increases in stress are symptom and findings-oriented, usually in close coordination between orthopedics, physiotherapy and the patient.

• Partial loading for 4–6 weeks after drilling/refixation, possibly longer for cartilage reconstruction
• Early, pain-adapted mobilization; If necessary, passive movement splint after surgery
• Progressive training plan: mobility → coordination → strength → sport-specific load
• Return to sport after approx. 4-9 months depending on the procedure and healing process (decided on a case-by-case basis)
• Regular checks with clinical examination and, if necessary, follow-up MRI

Overload peaks in the healing phase should be avoided. Quality and continuity of exercises are more important than speed. Sustainable correction of axial or technical deficits reduces the risk of relapse.

Course, prognosis and prevention

The prognosis is often good in adolescence if diagnosed early. In adults or late stages, healing may be difficult; An untreated unstable lesion can damage the cartilage surface and, in the long term, promote the development of osteoarthritis.

• Early detection improves the chances of recovery
• Complaint-adapted activity control prevents progression
• Consider axis optimization/inserts for varus/valgus deviation
• Technical training and strength/coordination in sports to relieve pressure
• Plan sufficient regeneration times in your training plans

It is important to set realistic goals without pressure. A careful return to sport is possible if the clinic and imaging allow this. Guarantees cannot be given seriously; we provide transparent information about opportunities and risks.

Differential diagnoses: What else is possible

Symptoms are similar to other knee diseases. A precise distinction is a prerequisite for the appropriate therapy.

• Circumscribed cartilage damage without bone involvement
• Meniscus lesions (medial/lateral)
• Plica syndrome or synovitis with irritating effusion
• Patellofemoral complaints/chondropathia patellae
• Osteochondral fracture after acute trauma
• Early osteoarthritis (gonarthrosis) in individual cases

Imaging (especially MRI) helps to differentiate cartilage, bone and soft tissue and enables a targeted approach.

When should I seek medical attention?

Seek orthopedic advice if knee pain persists for a few weeks, pain on exertion increases or recurring swelling occurs. An immediate clarification makes sense if:

• Blockages or feeling of pinching in the joint
• Acute, significant pain with limited mobility
• Repeated effusions after exercise despite rest
• Persistent complaints in young athletes

An early diagnosis can simplify therapy and improve the chances of recovery.

Our approach in Hamburg

In our orthopedic practice at Dorotheenstraße 48, 22301 Hamburg, we value structured, evidence-based treatment. After a detailed anamnesis and examination, we plan the imaging specifically and discuss the findings in an understandable manner.

• Priority for conservative measures in stable lesions
• Regular progress checks with clear milestones
• Surgical options only if there is a clear indication and detailed information
• Individual rehabilitation plans in close coordination with physiotherapy and sports medicine

You will receive an honest assessment without unrealistic promises. The goal is the best possible, sustainable joint function according to your everyday life and sport level.