A novel bioabsorbable conduit augments healing of avascular meniscal tears in a dog model

Background: Avascular meniscal tears are a common and costly problem for which current treatment options are limited. Hypothesis: A bioabsorbable conduit will allow for vascular tissue ingrowth that is associated with histologic and biomechanical evidence for avascular meniscal tear healing superior to that associated with meniscal trephining in dogs. Study Design: Controlled laboratory study. Methods: Twenty-five dogs underwent medial arthrotomy with creation of anterior and posterior tears in the medial menisci (N = 50 tears). The dogs were assigned treatments for their menisci: conduit (n = 29 tears) or trephine (n = 21 tears). Dogs were assessed for lameness by subjective scoring after surgery and sacrificed at 6, 12, or 24 weeks and assessed for articular cartilage damage, gross and histologic appearance of the operated menisci, and maximal load-to-failure values using tensile testing of meniscal tears. Tears were considered to demonstrate biomechanical integrity when histologic partial to complete healing was noted in conjunction with a measured load to failure that was significantly greater than controls. Results: Based on histologic assessment, the conduit was associated with complete (n = 4) or partial (n = 5) healing in all avascular defects at 12 and 24 weeks after surgery in this study. No healing was seen in defects treated by trephination and repair. No lameness associated with surgery or meniscal treatment was noted after 4 weeks. No articular cartilage damage was noted in any joint. At both 12 and 24 weeks, mean load to failure for normal menisci (43.2 N and 28.6 N, respectively) was significantly (P <.017) higher than conduit-treated (22.3 N and 16.0 N, respectively) and trephine-treated (0.6 N and 2.1 N, respectively) menisci, and load to failure for conduit-treated menisci was significantly (P <=.05) higher than trephine-treated menisci. Biomechanical integrity was noted in 10 of 14 conduit-treated menisci. Conclusion: Conduit treatment resulted in functional healing with bridging tissue and biomechanical integrity in 71 % of avascular meniscal defects for up to 6 months after surgery. No functional healing was noted in avascular meniscal tears treated by trephination and suture repair. Clinical Relevance: Clinical studies using the conduit in humans may be appropriate to determine the safety and efficacy of the device for cases of avascular and poorly vascularized meniscal tears, where the device can be successfully implanted from tear to meniscal rim, the tears can be surgically repaired, and patient compliance can be ensured.