Charlotte K Barton BVSc, MS, DACVS-LA, MS, MS, Katie A Seabaugh DVM, MS, DACVS-LA, DACVSMR, Ben Gadomski BS, PhD, Kevin Labus PhD, Ben Holmes BS, MS, PhD, Nathan J Castro BS, MS, PhD, Mike Hawes DVM, DACVP, Brad B Nelson DVM, PhD, DACVS-LA, Laurie R Goodrich DVM, PhD, DACVS.
Purpose: Articular cartilage defects have limited ability to repair, often healing with functionally and structurally inferior fibrocartilage. Currently, there are limited treatment options for cartilage defects that restore a healthy joint surface. ChondrograftTM is a 3D printed porous implant composed of nanomaterials with robust mechanical stiffness that fosters host integration (Nanochon). The aim of this study was to investigate ChondrograftTM in full thickness cartilage repair, assessing its ability to restore volume and integrate into surrounding cartilage and underlying subchondral bone as compared to debridement.
Materials and Methods: Bilateral 15mm diameter cartilage defects were created on the lateral trochlear ridge of the femur in 12 mature horses (IACUC approval 3171). One defect was implanted with ChondrograftTM and the contralateral limb was an untreated (empty/debrided) control defect. Horses were exercised starting day 28 and end points were at 36-weeks (4 horses) and 52-weeks (8 horses). Lameness examinations were performed every 4 weeks and arthroscopic evaluation was performed at 12 weeks. Post-mortem evaluation included macroscopic appearance, MRI, histological assessment and biomechanical testing.
Results: Lameness scores were not statistically different between ChondrograftTM and control limbs at any time points. At 12-week arthroscopy, ChondrograftTM treated defects had significantly improved fill and ICRS grades compared to empty defects (99% vs 45%, P < 0.0001 and 11.25±1.13 vs 4.08±3.09, P<0.0001)(Figure 1). Post-mortem ICRS grading identified significantly improved defect fill, repair tissue firmness and integration with surrounding cartilage (Figure 1). MRI MOCART scores were significantly higher for Nanochon treated defects compared to empty/debrided controls (74.58 vs 47.08, P=0.0008). Biomechanical testing revealed significantly higher repair tissue stiffness in ChondrograftTM treated defects compared to controls (P<0.0001)(Figure 2).
Conclusions: ChondrograftTM implants result in excellent defect filling and good integration to the surrounding cartilage, with similar biomechanical function to normal healthy articular cartilage. ChondrograftTM represents a viable improved treatment for full thickness chondral defects.
Figure 1. Arthroscopic images of the Nanochon 3D printed implant in a 15mm diameter full thickness cartilage defect or 15mm control/empty full thickness cartilage defect. A) Implant placement. B) Recheck arthroscopic evaluation at 12 weeks. C) Endpoint arthroscopic evaluation at 52 weeks. D) Defect creation. E) Recheck arthroscopic evaluation at 12 weeks. F) Endpoint arthroscopic evaluation at 52 weeks.
Figure 2. Bar plot to show the means and standard deviations of the stiffness of Nanochon ChondrograftTM and control repair tissue. There were no significant differences between locations within the Nanochon treated group. Within the control group * indicates a significant difference compared to the Repair Central location, and † indicates a significant difference compared to the Repair Peripheral location.
Presented at 18th ICRS Wold Congress “Joint Revolution”