OrthRaMS Seminar Series – Nic Fiorentino, PhD

Title: “Short-Term Longitudinal Changes in Joint Arthrokinematics and Microstructure in the Knees of Patients Following ACL Reconstruction with Meniscal Surgery”

Presenter: Nic Fiorentino, PhD (University of Vermont)

Post-traumatic osteoarthritis (PTOA) is an exceedingly common outcome following
anterior cruciate ligament reconstruction with meniscal surgery (ACLR+M), affecting
50-80% of patients 10-20 years after surgery. Despite the strong epidemiological data
the mechanisms underlying development of PTOA remain poorly understood. A
long-standing hypothesis suggests abnormal knee joint mechanics after surgery induce
deleterious compositional changes in cartilage, but this framework has limited in vivo
evidence, especially in the ACLR+M population. This seminar reports results from a
series of studies exploring early side-to-side differences in joint arthrokinematics and
cartilage composition in patients in the short-term after ACLR+M. Twelve participants
who underwent ACLR+M were assessed 1-2 years post-surgery and again one year later
at 2-3 years post-surgery. We measured joint arthrokinematics using a high-speed dual
fluoroscopy imaging system with model-based tracking that boasts a bias and precision
less than 1 mm and 1°, generating arthrokinematic measurements for tibiofemoral
translation, rotation, and cartilage-cartilage overlap during dynamics activities of
walking, jogging, lunging, rotating, and landing. Cartilage composition was evaluated
with quantitative magnetic resonance imaging (qMRI) relaxation times and included the
response to load applied with an MR-compatible loading device. We found significant
differences between surgical and contralateral knees in arthrokinematics during al
dynamic activities, as well as significant differences in composition for articular cartilage
and the meniscus. Longitudinal results demonstrated a trend toward a positive correla-
tion linking anteroposterior contact location differences during walking at 1-2 years
with longitudinal T1 rho changes in the lateral tibial compartment and a negative correla-
tion with the lateral femoral compartment. Overall, these studies highlight the impor-
tance of early mechanical and biological changes in this patient population that’s at a
highly elevated risk for PTOA. By combining longitudinal tracking with cross-sectional
assessments of mechanical and biological changes, this research provides valuable
insights into the early stages of PTOA, offering potential targets for clinical inter

• Fiorentino_OrthoRaMS_flyer.pdf