2015 ISAKOS Biennial Congress ePoster #1219

Increased Risk of Revision After Anterior Cruciate Ligament Reconstruction With Soft Tissue Allograft Compared to Hamstring Autograft

Gregory B. Maletis, MD, Baldwin Park, CA UNITED STATES
Jason Chen, MA, San Diego, CA UNITED STATES
Maria CS. Inacio, PhD, San Diego, CA UNITED STATES
Tad T Funahashi, MD, Newport Beach, CA UNITED STATES
Kaiser Permanente Surgical Outcomes and Analysis, San Diego, California, USA

FDA Status Not Applicable

Summary: Tissue processing of soft tissue allografts has a significant effect on the risk of revision surgery and that effect is most profound in patients <22 years of age and increases with time.

Abstract:

Introduction

The use of allograft tissue for anterior cruciate ligament reconstruction (ACLR) remains controversial. Numerous meta-analysis and systematic reviews of small clinical studies have not found differences between autograft and allograft outcomes but large registry studies have shown an increased risk of revision with allografts. The purpose of this study was to compare the risk of aseptic revision between hamstring tendon autografts and soft tissue allografts.

Methods

A retrospective cohort study of prospectively collected data was conducted using an US ACLR Registry. A cohort of primary unilateral ACLR cases reconstructed with hamstring autografts and soft tissue allografts (from any site) was identified. Aseptic revision was the end point of the study. Type of graft and allograft processing methods (non-processed, <1.8Mrads, >1.8 MRads irradiation, and BioCleanse processing) were the exposures of interest evaluated. Age (<22 and >22 years-old) was evaluated as an effect modifier. All analyses were adjusted for age, gender, and race. Kaplan-Meier curves and Cox proportional hazard models were employed. Hazard ratios (HR), 95% confidence intervals (CI) are provided.

Results

The soft tissue cohort had 9458 cases, 5774 (61.0%) were male, 4571 (48.3%) were White, 3751 (39.7%) cases used soft tissue allograft and 5707 (60.3%) cases used hamstring autograft. The median age was 34.6 years-old (IQR 24.1-43.2) for allograft cases and 24.3 years-old (IQR 17.7-33.8) for autograft cases. The adjusted overall risk of revision in allograft compared to autografts within 2 years of the surgery was 1.20 (95%CI 0.86-1.69, p=0.688) and after two years was 3.24 (95%CI 1.91-5.48, p<0.001). The adjusted risk of revision in allografts processed with BioCleanse (HR: 2.98, 95%CI 1.38-6.41, p=0.005) was associated with a higher risk of revision. Patients <22 years-old with BioCleanse processed grafts had the greatest risk (HR: 4.56, 95%CI 2.00-10.40), while those 22 years and older did not have a significantly different risk of revision (HR: 1.03, 95%CI 0.14-7.65) than hamstring autografts. For those with allografts treated with <1.8Mrad irradiation, the risk of revision was higher than with hamstring autografts after 2 years (HR: 2.50, 95%CI 1.40-4.46, p=0.002), and for those with >1.8Mrad irradiation it was higher after 1 year (HR: 2.84, 95%CI 1.77-4.56, p<0.001). Non-treated soft tissue allografts did not have a higher risk of revision when compared to autograft (p=0.680).

Conclusions

When soft tissue allografts are used for ACLR, both processing, time from surgery, and patient’s age affect the risk of revision when compared to hamstring autografts. Tissue processing has a significant effect on the risk of revision surgery and that effect is most profound in patients <22 years of age and increases with time. Surgeons and patients need to be aware of the increased risks of revision when soft tissue allograft is used for ACLR especially in patients <22 years-old.