1Department of Bioengineering, Hospital for Joint Diseases Orthopaedic Institute, New York, New York, U.S.A.
2Department of Sports Medicine, Hospital for Joint Diseases Orthopaedic Institute, New York, New York, U.S.A.
3Department of Orthopaedic Surgery, Eastern Hospital, Goteburg, Sweden
4Department of Orthopaedic Surgery, Hospital for Joint Diseases Orthopaedic Institute, New York, New York, U.S.A.
5Department of Pathology, Hospital for Joint Diseases Orthopaedic Institute, New York, New York, U.S.A.