Chondral and Osteochondral Injuries of the Knee 

 - Discussion:
    - articular cartilage injury and potential for repair;
    - rotational forces in direct trauma is the most common cause of injury to
      the articular cartilage;
    - in adults, the tidemark zone is the weak link between the overlying cartilage
      and subchondral
            bone and therefore shearing injuries most often produce a chondral
            injury rather than an osteochondral injury;
    -injury is mostly in wt bearing regions of articular cartilage, and usually in 
     medial compartment (4 times more common that lateral injuries); 
    - classification:
    - pediatric OCD: steochondritis dessicans 
    - natural history:
            - references:
                   - Isolated Full Thickness Chondral Injuries. Prevalance and Outcome of Treatment. A
                     Retrospective Study of 5233 Knee Arthroscopies.
                   - Articular cartilage defects: study of 25,124 knee arthroscopies
                   - Articular cartilage lesions in 993 consecutive knee arthroscopies

 - Exam:
    - symptoms of intermittent locking, recurrent effusions, crepitus, and persistant pain may all be associated
      with chondral injuries;
    - however, similar symptoms are found in extensor mech injuries; and meniscal injuries
    - with knee flexion, the anterior and central face of the medial femoral can be palpated (as opposed to
      the posteromedial joint line which indicates a meniscal tear);
    - w/ a dashboard type injury, consider PCL tear;

 - Radiographs: 
      - The accuracy of magnetic resonance imaging scanning and its influence on management decisions in knee
        surgery.
      - Sensitivity of routine 1.0-Tesla MRI versus arthroscopy as gold standard in fresh traumatic chondral lesions
        of the knee in young adults.
      - Diagnosis of chondral lesions of the knee joint: can MRI replace arthroscopy? A prospective study
      - Evaluation of cartilage defects in the knee: validity of clinical, magnetic-resonance-imaging and radiological
        findings compared with arthroscopy
     

             

- Non Operative Treatment:
    - articular steroid injection
    - anti-inflammatories
    - valgus unloading knee brace;

- Surgical Treatment Options:
    - debridement of chondral defects and microfracture 
    - mosaicplasty and cartilage transplants for chrondral injuries:  
    - enhanced microfracture with autolgous hamstring resurfacing;
    - role of allografts in repairing chondral defects: (see allografts);
    - growth factors: (see BMP)
          - as noted by Sellers et al 1997, treatment with rhBMP-2 significantly accelerated formation of new
            subchondral bone and improve the microscopic appearance of overlying articular cartilage;
                 - technical involved insertion of a BMP laden collagen sponge into a chondral defect;
                 - disadvantages: there may be a lack of integration of the repair tissue with the normal adjacent cartilage;
          - references:
                 - The repair of osteochondral defects using an exogenous fibrin clot. Study in dogs. GA Paletta
                    Am J. Sports Med Vol 20. 1992. p 725-731.
                 - The effect of (rhBMP-2) on the healing of full thickness defects of articualr cartilage.  RS Sellers
                    JBJS Vol 79-A. No 10. Oct 1997. p 1452.
    - arthroscopy of the degenerative knee (see osteoarthritis):