OCD Fixation — Osteochondritis Dissecans of the Knee

Why this approach — at MOS

OCD is a diagnosis that benefits from early identification and staged decision-making. The key question — is this lesion going to heal on its own or does it need surgery? — is answered by the combination of skeletal maturity (open versus closed growth plates), lesion stability on MRI, and the patient's response to a structured conservative trial.

We use MRI with specific OCD sequences (including fluid signal beneath the fragment and interface mapping) to assess stability more reliably than plain radiographs alone. Lesions with fluid signal completely surrounding the fragment, indicating full detachment, are treated surgically without waiting for a failed conservative trial.

For fixation, we prefer headless compression screws for their rigid fixation properties and compressed fragment-to-bone interface. Fragment preparation — adequate debridement and bone grafting of the interface — is as important as the fixation hardware. A well-prepared interface with good bone-to-bone contact and stable fixation predictably heals; a poorly prepared one fails regardless of implant choice. We follow the International Cartilage Repair Society (ICRS) OCD Study Group recommendations for both conservative management protocols and fixation technique. Patients from across Montgomery County, both adolescent and adult, who present with OCD receive a structured treatment pathway tailored to their lesion characteristics and stage.

Who is a candidate?

Indications

• Unstable OCD lesion (partially or completely detached fragment) with viable cartilage and bone suitable for fixation
• Stable OCD lesion that has failed 3–6 months of non-weight-bearing conservative management
• Large OCD lesion in a skeletally mature patient where early fixation is preferred over waiting for spontaneous healing
• OCD lesion with associated loose bodies in the joint

Contraindications

• Non-viable, fragmented, or severely degenerated fragment — fixation will not succeed; cartilage restoration is needed
• Completely detached loose body that has degenerated — remove and treat defect with appropriate cartilage procedure
• Advanced surrounding arthritis making cartilage preservation futile
• Very small stable lesion in a young patient with open growth plates responding to non-weight-bearing

Conservative Treatment First

Stable OCD lesions in skeletally immature patients (open growth plates) have a meaningful capacity to heal with conservative management. Treatment includes restricted weight-bearing or non-weight-bearing on the affected limb (sometimes with crutches or a brace) for 3–6 months, combined with activity restriction — specifically avoiding high-impact sports. Serial MRI is used to monitor healing. Spontaneous healing rates of up to 50–60% have been reported for stable lesions in adolescents managed conservatively. Surgery is indicated when conservative management fails or when the lesion is unstable at presentation. In skeletally mature patients, conservative healing is less reliable and the threshold for surgical intervention is lower.

The procedure

What Is OCD Fixation — Osteochondritis Dissecans of the Knee?

OCD fixation is an arthroscopic procedure that stabilizes a loose or partially detached osteochondritis dissecans (OCD) lesion — a segment of cartilage and bone that has partially separated from the femoral condyle — by drilling the lesion to stimulate healing, removing any loose debris, and securing the fragment back in place with absorbable or metal screws. Preserving the native cartilage is always the goal when the fragment is viable.

Osteochondritis dissecans is a condition in which a portion of bone beneath the cartilage loses its blood supply, becomes necrotic, and gradually separates from the surrounding bone. The exact cause is not fully understood, but repetitive microtrauma and vascular disruption are thought to play roles. It occurs most commonly in adolescents and young adults, typically on the classic location of the lateral aspect of the medial femoral condyle, though any articular surface can be affected.

OCD lesions are classified by stability. Stable lesions — where the overlying cartilage is intact and the lesion has not detached — are often managed conservatively. Unstable lesions — partially or completely detached — require surgical intervention. When the fragment is still viable (containing living bone and cartilage), fixation to restore it to its bed is always preferred over removal, because it preserves the native hyaline cartilage surface. If the fragment is non-viable, fragmented, or completely detached and deteriorated, cartilage restoration with microfracture, OATS, or allograft becomes necessary.

OCD fixation is particularly important in adolescent patients, whose open growth plates and remaining skeletal growth often provide an excellent healing environment when the lesion is stabilized early.

What Happens During OCD Fixation?

OCD fixation is performed arthroscopically at the ambulatory surgery center under general or regional anesthesia. The joint is fully inspected. The OCD lesion is identified and probed to assess stability, fragment quality, and the condition of the interface between the fragment and parent bone.

If the fragment is suitable for fixation, the interface is debrided — fibrous tissue and necrotic bone are removed from the undersurface of the fragment and the bed — to expose viable, bleeding cancellous bone on both sides. Bone graft (autologous bone from the tibial metaphysis or graft substitute) may be placed in the bed to support healing. The fragment is then anatomically reduced and held in place while fixation is applied.

Fixation options include headless compression screws (Herbert-type screws), absorbable pins or screws, or a combination. Headless screws provide rigid compression that promotes bone healing; absorbable implants eliminate the need for a second surgery to remove hardware but provide less rigid fixation. In adolescent patients with soft bone, implant selection is tailored to bone quality.

After fixation is confirmed, the knee is taken through range of motion to confirm the fragment is secure and the joint surfaces are congruent. Portals are closed and a brace or splint is applied.

Recovery timeline

Frequently Asked Questions