No proven long-term joint-preserving treatment options exist for patients with irreparable meniscal damage. This study aimed to assess gait kinematics and contact pressures of novel fibre-matrix reinforced polyvinyl alcohol-polyethylene glycol (PVA-PEG) hydrogel meniscus implanted ovine stifle joints against intact stifles in a gait simulator. The gait simulator controlled femoral flexion-extension and applied a 980N axial contact force to the distal end of the tibia, whose movement was guided by the joint natural ligaments (Bartolo; ORS 2021;p1657- LB). Five right stifle joints from sheep aged >2 years were implanted with a PVA-PEG total medial meniscus replacement, fixed to the tibia via transosseous tunnels and interference screws. Implanted stifle joint contact pressures and kinematics in the simulator were recorded and compared to the intact group. Contact pressures on the medial and lateral condyles were measured at 55° flexion using Fujifilm Prescale Low Pressure film inserted under the menisci. 3D kinematics were measured across two 30 second captures using the Optotrak Certus motion-tracking system (Northern Digital Inc.). Medial peak pressures were not significantly different between the implanted and intact groups (p>0.4), while lateral peak pressures were significantly higher in the implanted group (p<0.01). Implanted stifle joint kinematics in the simulator did not differ significantly from the intact baseline (p>0.01), except for in distraction-compression (p<0.01). Our findings show that the fibre-matrix reinforced PVA-PEG hydrogel meniscal replacement restored the medial peak contact pressures. Similar to published literature (Fischenich; ABE 2018;46(11):1–12), the lateral peak pressures in the implanted group were higher than the intact. Joint kinematics were similar across groups, with slightly increased internal-external rotation in the implanted group. These findings highlight the effectiveness of the proposed approach and motivate future work on the development of a total meniscal replacement.
Articular cartilage damage is a primary outcome of pre-clinical and clinical studies evaluating meniscal and cartilage repair or replacement techniques. Recent studies have quantitatively characterized India Ink stained cartilage damage through light reflectance and the application of local or global thresholds. We develop a method for the quantitative characterisation of inked cartilage damage with improved generalisation capability, and compare its performance to the threshold-based baseline approach against gold standard labels. The Trainable WEKA Segmentation (TWS) tool (Arganda-Carreras et al., 2017) available in Fiji (Rueden et al., 2017) was used to train two separate Random Forest classifiers to automatically segment cartilage damage on ink stained cadaveric ovine stifle joints. Gold standard labels were manually annotated for the training, validation and test datasets for each of the femoral and tibial classifiers. Each dataset included a sample of medial and lateral femoral condyles and tibial plateaus from various stifle joints, selected to ensure no overlap across datasets according to ovine identifier. Training was performed on the training data with the TWS tool using edge, texture and noise reduction filters selected for their suitability and performance. The two trained classifiers were then applied to the validation data to output damage probability maps, on which a threshold value was calibrated. Model predictions on the unseen test set were evaluated against the gold standard labels using the Dice Similarity Coefficient (DSC) – an overlap-based metric, and compared with results for the baseline global threshold approach applied in Fiji as shown in Figures 1 and 2.Objectives
Methods
