What are the treatment options for an osteochondral lesion on the medial femoral condyle?

Treatment of Osteochondral Lesions of the Medial Femoral Condyle

Treatment selection depends primarily on lesion size: microfracture for defects <2 cm², osteochondral allograft transplantation for defects 2-6 cm², and consideration of arthroplasty for defects >6 cm in appropriate candidates. 1

Initial Assessment and Patient Selection

Before proceeding with any surgical intervention, patients must meet specific criteria for joint-preserving surgery 1, 2:

• Age: Skeletal maturity to 50 years 1, 2
• Radiographic findings: Minimal (Tönnis grade ≤1) or no osteoarthritis 1
• Inflammatory status: No inflammatory arthritis 1
• Lesion characteristics: Full-thickness defects, but no bipolar lesions (both femoral and tibial involvement) 1, 2
• Functional capacity: Ability to perform rigorous postoperative physical therapy 1

Critical prerequisite: All patients must complete and document at least 6 weeks of supervised, in-person physical therapy with objective documentation of compliance and failure to achieve adequate symptom relief before surgical intervention 2.

Treatment Algorithm Based on Lesion Size

Small Lesions (<2 cm²)

First-line treatment: Microfracture 1

• Creates small holes in subchondral bone to release marrow cells and growth factors 1
• Results in 93% fill rate with good-quality cartilage macroscopically at second-look arthroscopy 1
• Alternative option: Mosaicplasty (autologous osteochondral cylindrical grafts) for patients <45 years with focal full-thickness lesions <3 cm² 1

Medium Lesions (2-6 cm²)

First-line treatment: Osteochondral allograft transplantation 1, 2, 3

This is the preferred treatment for symptomatic, full-thickness osteochondral defects ≥2 cm² in patients who have failed conservative management 3. The procedure involves replacing damaged cartilage with subchondral bone and cartilage from a deceased donor 3.

Key technical considerations:

• Requires meticulous preoperative planning with radiographs to evaluate alignment, estimate lesion size, and aid in donor femoral condyle matching 3
• Host tissue typically removed to depth of 5-8 mm 3
• Graft survival rates: 94% at 5 years and 84% at 10 years 4
• Return to sport rates as high as 88% with average time of 9.6 months 3

Mandatory prerequisites before osteochondral allograft: 2

• Definitive imaging assessment of tibial plateau to confirm opposing articular surface is free of significant disease
• Meniscal status must be addressed—either document adequate remaining meniscal tissue or plan concurrent meniscal allograft transplantation
• Stable knee with negative Lachman, anterior/posterior drawer, and pivot shift tests

Second-line options: 1

• Microfracture (if lesion not identified preoperatively)
• Osteochondral allograft transplant (single plug)

Large Lesions (6-8 cm²)

First-line treatment: Osteochondral allograft transplantation 1

For these larger defects, osteochondral allograft is preferred over autograft due to donor site limitations with autograft 2.

Very Large Lesions (>8 cm²)

Consider total knee arthroplasty 1

This is particularly appropriate for patients approaching the upper age limit (near 50 years) or those with early osteoarthritic changes 1.

Special Considerations for Osteochondritis Dissecans (OCD)

While the AAOS guidelines acknowledge that appropriate treatment for OCD remains largely unknown with a paucity of high-quality studies 5, the following surgical options are discussed:

For stable lesions predicted to fail nonsurgical treatment: 5

• Anterograde versus retrograde drilling (optimal approach unclear)

For unstable lesions: 5

• Fixation options include minifragment screws, variable pitch screws, or bioabsorbable pins (optimal fixation method unclear)

For non-salvageable OCD lesions: 5

• Fresh osteochondral allograft or autologous chondrocyte implantation

For large, uncontained OCD lesions of the medial femoral condyle, unicompartmental osteochondral allograft augmented with screw fixation can be utilized 6.

Clinical Outcomes and Evidence Quality

Important caveat: The literature on cartilage restoration procedures is limited to small case series and case reports with no long-term studies or control groups 1. Despite this limitation, osteochondral allograft transplantation has shown significantly improved patient-reported outcomes at mean follow-up of 12.3 years 3.

For spontaneous osteonecrosis of the knee (SONK) lesions on the medial femoral condyle, fresh osteochondral allograft has demonstrated excellent efficacy with 0% allograft failure rate at median 7.1-year follow-up in patients with stage 2 and 3 lesions 4.

Postoperative Management

Following osteochondral allograft transplantation 3:

• Immediate passive range of motion
• Heel-touch weight-bearing begins at 6 weeks
• Return to sport-specific activity after 8 months, as tolerated

Common Pitfalls to Avoid

• Do not proceed with osteochondral allograft if bipolar lesions are present (both femoral and tibial involvement), as this is a contraindication 2
• Do not ignore meniscal status—meniscal deficiency must be addressed before or concurrent with osteochondral allograft 2
• Do not consider stem cell therapy—this is not currently recommended due to heterogeneity and lack of standardization 1
• Ensure perpendicular alignment when using cannulated cylinder for both host lesion and graft tissue to ensure symmetric size estimations 3
• Save subchondral bone shavings when preparing the host lesion, as these can fill space if graft depth is insufficient 3