Qualitative and Quantitative Evaluation of Loose Bodies as a Novel Cell Source for Autologous Chondrocyte Implantation.

Background: Autologous chondrocyte implantation (ACI) has recently produced successful outcomes, but donor site morbidity remains an urgent issue to be resolved. Thus, alternative cell sources are highly desirable to minimize donor site morbidity. Purpose: To qualitatively and quantitatively evaluate the potential of loose bodies as a novel cell source for ACI. Study Design: Controlled laboratory study. Methods: Loose bodies were obtained from 10 patients during arthroscopic surgery. They were evaluated by gross appearance and histology and classified into normal, abnormal, and no-cartilage groups. Then, 3-dimensional (3D)-cultured cartilage was prepared using chondrocytes from the loose bodies, and cell proliferation and glycosaminoglycan production in the 3D-cultured cartilage were compared with those from native cartilage obtained from patients who underwent total knee arthroplasty. Finally, expression of 42 genes by primary chondrocytes from the loose bodies was analyzed by chondrocyte gene spatial mapping analysis (CGSMA) and compared with that of reference chondrocytes to visualize their global properties, including ossification and denaturation. Results: Of 10 loose bodies, 4 were histologically classified into the normal cartilage group, 4 into the abnormal cartilage group, and 2 into the no-cartilage group. The mean cell proliferation rate of 3D-cultured cartilage from the loose bodies in the normal and abnormal cartilage groups was significantly higher than that of the native cartilage ( Conclusion: A subset of loose bodies demonstrated matrix-producing capacity without ossification or denaturation, supporting their potential as a cell source for ACI. Clinical Relevance: Appropriately selected loose bodies are a potential cell source for ACI while minimizing donor site morbidity.