A novel large animal model of posttraumatic osteoarthritis induced by inflammation with mechanical stability.

OBJECTIVES: Animal models are needed to reliably separate the effects of mechanical joint instability and inflammation on posttraumatic osteoarthritis (PTOA) pathogenesis. We hypothesized that our modified intra-articular drilling (mIAD) procedure induces cartilage damage and synovial changes through increased inflammation without causing changes in gait. METHODS: Twenty-four Yucatan minipigs were randomized into the mIAD (n=12) or sham control group (n=12). mIAD animals had two osseous tunnels drilled into each of the tibia and femur adjacent to the anterior cruciate ligament (ACL) attachment sites on the left hind knee. Surgical and contralateral limbs were harvested 15 weeks post-surgery. Cartilage degeneration was evaluated macroscopically and histologically. Synovial changes were evaluated histologically. Interleukin-1 beta (IL-1ß), nuclear factor kappa B (NF-κB), and tumor necrosis factor alpha (TNF-α) mRNA expression levels in the synovial membrane were measured using quantitative real-time polymerase chain reaction. IL-1ß and NF-κB levels in chondrocytes were assessed using immunohistochemistry. Load asymmetry during gait was recorded by a pressure-sensing walkway system before and after surgery. RESULTS: The mIAD surgical knees demonstrated greater gross and histological cartilage damage than contralateral (P<.01) and sham knees (P<.05). Synovitis was present only in the mIAD surgical knee. Synovial inflammatory marker (IL-1ß, NF-κB, and TNF-α) expression was three times higher in the mIAD surgical knee than the contralateral (P<.05). Chondrocyte IL-1ß and NF-κB levels were highest in the mIAD surgical knee. In general, there were no significant changes in gait. CONCLUSIONS: The mIAD model induced PTOA through inflammation without affecting gait mechanics. This large animal model has significant applications for evaluating the role of inflammation in PTOA and for developing therapies aimed at reducing inflammation following joint injury.

Localized Pigmented Villonodular Synovitis Originating from the Lateral Meniscus in a 17-year-old: Case Report and Literature Review of Meniscal-Associated Localized PVNS.

Tenosynovial giant cell tumors (TSGCT) are benign tumors originating from the synovial joint, bursa, or tendon sheath. Localized pigmented villonodular synovitis (PVNS), a subtype of TSGCT, commonly affects the hands and feet and has also been reported in the literature in the knee joint. There is sparse literature on localized PVNS arising specifically from meniscal tissue. We present a case report of a 17-year- old male with symptoms and MRI findings consistent with a lateral meniscus tear. Intraoperatively, the patient was found to have a mass originating from the torn meniscal tissue, which was confirmed by pathology to be a TSGCT. We performed a literature review of intra-articular localized PVNS within the knee presenting as a meniscal tear.

The Physiological Effects, Including Risks and Potential Benefits, of Cannabis for Patients Undergoing Elective Orthopedic Procedures.

Given the evolving regulations regarding and availability of cannabis in the United States, physicians should understand the risks and benefits associated with its use. Patients are interested in learning about the use of cannabis for the management of orthopedic pain and any potential risks associated with it when undergoing elective surgery. Edible and topical cannabis products appear to have fewer side effects than inhaled cannabis products. A review of the literature was performed regarding different modes of administration and their related risks and potential benefits specifically regarding perioperative concerns for elective orthopedic procedures. Larger studies are necessary to further determine the efficacy, safety, and side effect profile of cannabis. [Orthopedics. 2021;44(3):e314-e319.].