Prof. Kerkhoffs specializes in development and evaluation of diagnostic and surgical methods to treat disorders of the lower extremity with special emphasis on the cartilage lesions of the ankle joint and muscle injuries. In addition; he and his team have been recognized for providing excellent care to elite athletes by the National Olympic Committee (honorary Team NL Preferred Physician) and the International Olympic Committee (Official Research Center. Ankle cartilage injuries; muscle injuries and stress fractures are typical problems that occur in elite athletes. Prof. Kerkhoffs helps to enable these athletes to return to sport safely and quickly by fundamental research on tissue healing properties; optimization of minimally invasion access to the pathology - recently with needle arthroscopy -; excellent preoperative examination by developing state-of-the-art imaging techniques in collaboration of the dept. of Radiology; and excellent follow up with tailored rehab programs and individual monitoring. Examples of new techniques that have been introduced by him are the LDFF technique and various cartilage repair techniques including the TOPIC graft.