Evaluation of histological scoring systems for tissue-engineered, repaired and osteoarthritic cartilage

Osteoarthritis and Cartilage Volume 18, Issue 1, January 2010, Pages 12-23 -------------------------------------------------------------------------------- Review Evaluation of histological scoring systems for tissue-engineered, repaired and osteoarthritic cartilage M. Rutgers†, M.J.P. van Pelt†, W.J.A. Dhert†, ‡, L.B. Creemers† and D.B.F. Saris†, , † Department of Orthopaedics, University Medical Center Utrecht, The Netherlands ‡ Faculty of Veterinary Sciences, Utrecht University, The Netherlands Received 18 February 2009; accepted 2 August 2009. Available online 2 September 2009. Summary Objective Regeneration of hyaline cartilage has been the focus of an increasing number of research groups around the world. One of the most important outcome measures in evaluation of its success is the histological quality of cartilaginous tissue. Currently, a variety of histological scoring systems is used to describe the quality of osteoarthritic, in vivo repaired or in vitro engineered tissue. This review aims to provide an overview of past and currently used histological scoring systems, in an effort to aid cartilage researchers in choosing adequate and validated cartilage histological scoring systems. Methods Histological scoring systems for analysis of osteoarthritic, tissue engineered and in vivo repaired cartilage were reviewed. The chronological development as well as the validity and practical applicability of the scoring systems is evaluated. Results The Histological-Histochemical Grading System (HHGS) or a HHGS-related score is most often used for evaluation of osteoarthritic cartilage, however the Osteoarthritis Research Society International (OARSI) Osteoarthritis Cartilage Histopathology Assessment System seems a valid alternative. The O'Driscoll score and the International Cartilage Repair Society (ICRS) II score may be used for in vivo repaired cartilage. The ‘Bern score’ seems most adequate for evaluation ofin vitro engineered cartilage. Conclusion A great variety of histological scoring systems exists for analysis of osteoarthritic or normal, in vivo repaired or tissue-engineered cartilage, but only few have been validated. Use of these validated scores may considerably improve exchange of information necessary for advances in the field of cartilage regeneration.