Histopathological Scores for Tissue-Engineered, Repaired and Degenerated Tendon: A Systematic Review of the Literature

Purpose: This systematic review analyzes histological scoring systems for degenerative tendon-enthesis changes, ex vivo tendon-enthesis repair and tissue-engineered tendon-enthesis repair. A secondary aim is to establish the validity and applicability of these scores to find a comprehensive and validated histological scoring system for the evaluation of tendon-enthesis tissue. Methods: We performed a systematic review of the literature by analyzing the following databases: PubMed, Embase, Medline, CINAHL, and Cochrane. The methodology of the study was developed according to the PRISMA guidelines. Results: Twenty-seven articles, describing a total of 9 scores for tendinopathy, 6 scores for tendon ruptures, and 12 scores for tendon regeneration were included. For enthesis changes, 4 studies describe a total of 3 scores for enthesopathy and 1 scores for enthesis regeneration. The Movin score and its modifications seem be the more comprehensive to assess the degenerative changes; the Soslowsky score, the Watkins score, the Novel scoring system and the Burssens score seem be the more comprehensive to assess tendon repair process. Only the Matthys score assesses the histological changes in enthesopathies, and the modified Watkins score has been well applied to assess enthesis repair. Conclusion: The assessment of tendon-enthesis structure can be performed with several histological scoring systems previously published in literature. However, no studies have been performed to validate these score in research settings. Further experimental and clinical studies should be developed to provide a comprehensive and validated scoring system for the histological assessment of tendon-enthesis repair.