Background:Anterior cruciate ligament (ACL) injury increases the risk of meniscus and articular cartilage damage, but the causes are not well understood. Previous in vitro studies were static, required extensive knee dissection, and likely altered meniscal and cartilage contact due to the insertion of pressure sensing devices.Hypothesis:ACL deficiency will lead to increased translation of the lateral meniscus and increased deformation of the medial meniscus as well as alter cartilage contact location, strain, and area.Study Design:Descriptive laboratory study.Methods:With minimally invasive techniques, six 1.0-mm tantalum beads were implanted into the medial and lateral menisci of 6 fresh-frozen cadaveric knees. Dynamic stereo x-rays (DSXs) were obtained during dynamic knee flexion (from 15° to 60°, simulating a standing squat) with a 46-kg load in intact and ACL-deficient states. Knee kinematics, meniscal movement and deformation, and cartilage contact were compared by novel imaging coregistration.Results:During dynamic knee flexion from 15° to 60°, the tibia translated 2.6 mm (P = .05) more anteriorly, with 2.3° more internal rotation (P = .04) with ACL deficiency. The medial and lateral menisci, respectively, translated posteriorly an additional 0.7 mm (P = .05) and 1.0 mm (P = .03). Medial and lateral compartment cartilage contact location moved posteriorly (2.0 mm [P = .05] and 2.0 mm [P = .04], respectively).Conclusion:The lateral meniscus showed greater translation with ACL deficiency compared with the medial meniscus, which may explain the greater incidences of acute lateral meniscus tears and chronic medial meniscus tears. Furthermore, cartilage contact location moved further posteriorly than that of the meniscus in both compartments, possibly imparting more meniscal stresses that may lead to early degeneration. This new, minimally invasive, dynamic in vitro model allows the study of meniscus function and cartilage contact and can be applied to evaluate different pathologies and surgical techniques.Clinical Relevance:This novel model illustrates that ACL injury may lead to significant meniscus and cartilage abnormalities acutely, and these parameters are dynamically measurable while maintaining native anatomy.
Background
Surgical resection with negative margins is the foundation of extremity sarcoma management. Failure to achieve negative surgical margins can result in local recurrence (LR), a potentially devastating complication. Indocyanine green (ICG) is a US FDA-approved fluorophore previously used to guide carcinoma resections. We investigated the potential of ICG as an intraoperative guide during experimental sarcoma resection.
Methods
Fifty 6-week-old immunocompetent Balb/c female mice received left proximal tibia paraphyseal injections of 5 × 10
5
K7M2 murine osteosarcoma cells. Animals were separated into two groups (
n
= 25 each): (1) ICG-assisted surgical resection; and (2) no ICG-assisted resection. Resections were performed 4 weeks after primary tumor engraftment. All animals received 7.5 ug ICG via retro-orbital injection 12 h prior to surgery. ICG fluorescence measurements and clinical evaluations were performed 4 weeks after resection to detect LR.
Results
Eleven of 25 animals from each group developed gross tumors. Four weeks after resection, group 1 had 0/11 tumor recurrences, while group 2 had recurrences in 9/11 (81.8%) experimental mice (
p
< 0.0002) (Fig.
2
). There was a 100% NPV in group 1, and no tumor recurrence with fluorescence-free margins after the primary surgery. Group 2 had a 100% positive predictive value for the development of an LR if any fluorescent signal was present at the surgical margin after resection.
Conclusion
Intraoperative ICG guidance led to reliably negative surgical margins and a diminished LR rate. Given the benign safety profile of ICG and its prior clinical success, these results could be immediately translatable to the clinical realm.
Tumor-to-tumor metastasis is an unusual phenomenon wherein one distinct malignancy is present within the substance of another independent tumor. This event is rare, difficult to detect with imaging, and, due to conflicting terminology in the literature, can be challenging to classify. This article reports the first documented case of tumor-to-tumor metastasis involving prostatic adenocarcinoma and myxoid liposarcoma, reviews the available literature for carcinoma metastatic to sarcoma, and discusses the current situation within the context of the established criteria for the classification of combination tumors.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.