Implant Associated Meniscus Micro-Tears: Imaging Human Cadaveric Menisci

Abstract

Currently, no available studies evaluate the tissue trauma inflicted on menisci by commonly used meniscus repair devices and implants. The purpose of this study was to investigate the pattern and size of micro-tears imposed on menisci by tear repair implants. The ability to visualize and understand tissue damage may guide future clinical management of patients and surgical device development. The purpose of this study is to evaluate trauma created to meniscal tissue after repair using commonly available repair devices. Thirty three fresh frozen human cadaveric medial and lateral menisci were used in this study. The following all-inside repair devices were evaluated; Ultra Fast-Fix, Fast-Fix 360, Depuy Mitek 0o and 12o TRUESPAN, ConMed Sequent, and Zimmer Biomet MaxFire in addition to inside-out double armed meniscus needles with HiFi and Orthocord suture. All menisci with preexisting tears and fraying were eliminated upon inspection. Right and left menisci were randomly evaluated. Samples were stained using India Ink, fixed in neutral 10% formalin, and stored at 4oC. A QICLICK-F-M-12-CCd camera was used to generate high resolution imaging. Micro-tear patterns were classified as linear, semilunar, or stellate. Tear length was defined using maximum diameter and measured using ImageJ software. Student t-tests and ANOVA were used to determine statistical significance ( = 0.05). Three hundred and eighty six micro-tears were analyzed with an average tear length of 2.04 mm (std dev = 0.83). For all-inside implants, micro-tear patterns (n = 289) were 18.7% linear, 41.9% semilunar, 39.4% stellate, while inside-out needles (n = 97) were 97.9% stellate and 2.1% linear. Among all-inside devices, average micro-tear lengths of semilunar, stellate, and linear were respectively 2.30 mm, 2.45 mm, 2.65 mm (F = 8.66, p < 0.05). All-inside devices averaged 2.42 mm while inside-out needles averaged 0.88 mm (p < 0.05). Of the all-inside devices, Sequent and Biomet averaged larger micro-tears than Ultra Fast-Fix, Fast-Fix 360, and Mitek 0o (F = 23.7, p < 0.05). HiFi averaged a smaller micro-tear size than Orthocord, respectively 0.82 mm and 0.94 mm (p < 0.05). Commonly used meniscus repair device implants produce the following tear patterns: linear, semilunar, and stellate. All devices create surrounding tissue trauma, which was visualized using a novel staining protocol. Of the all-inside devices, Ultra Fast-Fix, Fast-Fix 360, and Mitek 0o out-performed Sequent and Biomet. Inside-out double-armed needles produced a significantly smaller footprint than all-inside devices. The smaller footprint of inside-out needles may suggest a clinical advantage due to the decreased surrounding tissue damage generated in our model, however, more research is needed to properly evaluate.