2015 ISAKOS Biennial Congress ePoster #424

The Use of Scaffold Thimble Using 3D Bio-Printing Technique with Mesenchymal Stem Cells in Anterior Cruciate Ligament Reconstruction of a Rabbit Model: New Strategy to Enhance Tendon Graft Healing

Sin Hyung Park, MD, Seoul KOREA, REPUBLIC OF
Sang Won Moon, MD, Busan KOREA, REPUBLIC OF
Joon-Ho Wang, MD, PhD, Seoul KOREA, REPUBLIC OF
Dong-Woo Cho, PhD, Pohang KOREA, REPUBLIC OF
Yeongjin Choi, PhD, Pohang KOREA, REPUBLIC OF
Jin-Hwan Ahn, MD, Seoul KOREA, REPUBLIC OF
Byung-Hoon Lee, MD, PhD, Gwangju KOREA, REPUBLIC OF

Samsung Medical center, Seoul, KOREA

FDA Status Cleared

Summary: The use of Scaffold thimble that was made by 3D bio-printing technique and that was seeded MSC in ACL reconstruction of rabbit model showed no immune rejection and the good result in enhancement of osteointegration between tendon and tunnel bone.

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Abstract:

Purpose

Mesenchymal stem cells (MSCs) enhance osteointegration of the inserted tendon graft following anterior cruciate ligament (ACL) reconstruction. As carrier of MSC, liquid scaffold like fibrin glue is usually used. But liquid scaffold can be loss when the graft pass the tunnel for ACL reconstruction. If solid scaffold that seeded consistent amount of MSCs is used, the graft can pass tunnel without loss of MSC, and the consistent amount of MSC can be inserted to enhance osteointegration. The purpose of this study was to investigate the efficacy of insertion of scaffold thimble that was made by 3D bio-printing technique with MSCs in ACL reconstruction in a rabbit model.

Methods

ACL reconstructions using hamstring tendons were performed on both legs of 15 adult rabbits. Scaffold thimble was made by 3D bio-printing technique. Before ACL reconstruction, scaffold thimble was seeded with MSCs. Seeding MSC on scaffold thimble was confirmed by Live/Dead cell stain before ACL reconstruction. The 30 bone tunnels were treated by scaffold thimble with or without MSCs before passing the graft. The specimens were harvested at 4, 8, and 12 weeks. A gross finding of the knee joint, a histological assessment using hematoxylin and eosin staining, immunohistochemical (IHC) staining for collagen type II, and an tunnel cross sectional area using micro-computed tomography (CT) were evaluated.

Results

In gross finding, No evidence of infection or immune rejection was detected. ACL tear, degenerative changes of articular cartilage, meniscal injuries were not visible in any knees. Graft laxity was checked grossly by the anterior drawer test in all specimens, and a firm end-point was felt in all specimens in both groups. In histological assessment, a smooth transition from bone to tendon through broad fibrocartilage formation was identified in the treatment group, and the interface zone showed abundant collagen type II production on IHC staining. Histological scores for the bone-tendon healing were higher in the treatment group than those in the control group at all time points. But there was not different significantly (P = 0.314). Micro-CT at 12 weeks showed smaller tibial(control, 6.6 ± 2.3 mm2; treatment, 5.8 ± 3.3 mm2, P = 0.657) and femoral (control, 9.6 ± 2.9 mm2 ; treatment, 6.0 ± 2.6 mm2, P = 0.074) bone tunnel enlargement in the treated group than that in the control group. In part of both groups, scaffold thimble was remained, not dissolved until 12 weeks.

Conclusion

The use of Scaffold thimble that was made by 3D bio-printing technique and that was seeded MSC in ACL reconstruction of rabbit model showed no immune rejection and the good result in enhancement of osteointegration between tendon and tunnel bone.