Knee Joint Preservation Techniques

MACI (Matrix-induced Autologous Chondrocyte Implantation)

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• Two-part procedure commonly used to treat cartilage defects/lesions of the knee or kneecap
• Patient’s own cells are harvested, grown, and reimplanted
• 1^st Arthroscopic Procedure – Cartilage biopsy/harvest
  • Evaluation of the condition of the cartilage, remove damaged tissue from the knee (if necessary), and harvest a bit of cartilage from non-weightbearing regions of the knee
  • Procedure takes ~30 minutes and involves 2 small incisions
  • Following the first procedure, the patient can immediately bear weight and return to activity as tolerated. Most can return to work within a day or two. 
• Cartilage Preparation
  • Harvested cartilage is sent to a laboratory to grow on a collagen membrane/matrix for approximately one month
    • New cartilage cells are stored and usable for up to 5-years.  
• 2^nd Open Procedure – Cartilage Implantation
  • Newly grown cartilage is cut to precisely fit the patient’s defect and glued into place
  • Procedure takes ~1 hour and involves an open approach with a larger incision
  • Following the second procedure, patients will be expected to wear a brace for 6 weeks and use a continuous passive motion machine (CPM). Patients will start physical therapy 4-6 weeks after surgery. However, recovery timelines may differ if additional procedures are needed.  
• Your specific recovery timeline will be clearly outlined by Dr. Martin at the time of the procedure.  

Osteochondral Grafting

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• Commonly used to treat lesions/defects in the knee that involve both cartilage and underlying bone
  • Replaces lesion with healthy tissue (the graft)
• Depending on the size of the lesions, the graft my come from
  • Patient’s own body (osteochondral autograft)
    • If lesion is small (< 2cm), the graft can come from peripheral non-weight bearing areas of the patients knee
  •  Tissue donor (osteochondral allograft)
    • If the lesion is medium or large (> 2cm), the graft will come from a tissue donor
• Joint malalignment, ligamentous instability, and meniscal deficiency may be addressed at the time of surgery (if indicated)
  • Maximizes longevity of the graft and prevents additional damage or injury
• Following surgery, patients will be expected to wear a brace, refrain from weight bearing, and use a continuous passive motion machine (CPM) for 6 weeks. After 6 weeks, patients can gradually increase weight bearing and forgo the use of a brace. Return to sport typically occurs after 6-9 months. 
• Your specific recovery timeline will be clearly outlined by Dr. Martin at the time of the procedure.  

Microfracture

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• Commonly used to treat cartilage lesions/defects that expose the underlying bone in the knee by using the body’s own healing abilities 
• Performed arthroscopically through three small incisions
  • First, the surgeon evaluates the lesion and removes any loose or unstable cartilage, ensuring a smooth and stable cartilage surface surrounds the lesion. 
  • Multiple holes, or ‘microfractures’, are then created in the bone underneath the lesion. 
  • Blood and bone marrow cells travel through the holes and combine on the surface of the lesion, forming a “marrow-rich clot” that serves as the basis for new tissue formation. 
• New tissue formation is a gradual process
  • It may take 2-6 months after surgery for patients to experience significant improvement in pain and function
• Following surgery, patients will be expected to wear a brace, refrain from weight bearing, and use a continuous passive motion machine (CPM) for 6 weeks. After 6 weeks, patients can gradually increase weight bearing and forgo the use of a brace. Return to sport typically occurs after 6-9 months.  
• Your specific recovery timeline will be clearly outlined by Dr. Martin at the time of the procedure.