Neuralgic and Nociceptive Pain in the Knee as a Cause of the Treatment Failure after Cartilage Repair Surgery: Two Case Reports

Objective: Cartilage injuries are one of the most frequent causes of knee pain. Other causes such as meniscus tears, synovial plica, synovitis, partial and total ligament ruptures are rather easy to identify by standard diagnostic methods and diagnostic arthroscopy. In this study we are describing two other clinical states, which could be the cause of the knee pain and should be addressed before a decision for operative treatment of cartilage injury has been made by a surgeon. Materials and Methods: Two patients with isolated focal defects due to previous trauma to the knee were diagnosed both using magnetic resonance imaging preoperatively and intraoperatively during arthroscopy. These were operated arthroscopically with standard procedure for microfracture. Both patients had treatment failure without a sign of significant improvement after six and twelve months. Results: Second look arthroscopy was performed in both cases due to the treatment failure and close to normal cartilage was found in the patella in first case and both in trochlea and medial femoral condyle in other case. No other cause of pain could be identified both with second look arthroscopy and magnetic resonance imaging done 6-12 months postoperatively. The patients were diagnosed with neuralgic pain in one case, and nociceptive pain in other case. Conclusion: These states are rare, but have to be addressed by the surgeon before making the decision about the operative treatment. By doing so, one could avoid eventual treatment failure and exposition of the patient to an unnecessary risk of complications during the surgery.