In this study 9 patients were examined. All patients in the study group had undergone bi or tricompartimental knee arthroplasties. Criteria for inclusion in the study were the absence of arthritic changes in the external femoro-tibial compartment on the preoperative radiological examination (Kellgren-Lawrence stage 0 and 1). The mean age of patients was 56.1 years (range between 52 and 61 years), the ratio female: male was 6:3.
All patients selected in the study group performed a MRI investigation, for maximum 21 days preoperatively. The MRI studies were performed with a clinical 1.5T MRI system with Tim technology (Magnetom Avanto, Siemens, Germany) using a standard extremity coil and eight-channel knee coil year. In the T2 relaxation times our Examinations were obtained from T2-maps reconstructed using a multi-echo spin echo (SE) measurement with a repetition time (TR) of 4130 ms and echo times (TE) between 10ms (minimum) and 87 ms (maximal value). Field of View (FoV) WAS 200x200mm, 320x320 pixel matrix and voxel size 0.6x0.6x3.0mm. All of the images Were Prepared Within the syngoMapIt using Inline Technology. These post-processed using maps Were syngoFusion to overlay maps with Their Corresponding These anatomical images and to conduct manual cartilage segmentation (Figure 1A, B).
The interpretation of the acquired MRI data was performed by two independent observers after a prior randomization of the patients. The study area included an area of 4mm diameter from the center of the lateral tibial plateau. Measurements were recorded differently depending on the depth of the examined cartilage. The thickness of the tibial plateau cartilage was divided into two halves: deep and superficial, the average values for the two areas were recorded. For the comparative analysis OCT versus MRI T2mapping technique were used only the values (in msec), obtained in the superficial half of the cartilage layer.
The surgical procedure was performed for all patients in the 2nd Department of Orthopedics and Traumatology of the Emergency County Hospital Timisoara. In all cases we used ACGII system (Biomet, Warsaw, Indiana). Seven of the patients received a tricompartmental knee endoprostheses the other two underwent a bicompartmental knee arthroplasty (arthroplasty of the medial and lateral tibio-femoral compartments). During tibial plateau osteotomy, attention was paid in order to extract enblock the whole tibial articular surface, avoiding damage of the articular cartilage especially in the lateral tibio-femoral compartment (Figure 2).
The tibial articular fragment containing the lateral and medial tibial plateaus was examined with the OCT technique. This examination was performed only for the lateral tibial plateau within 3 hours postoperatively after a standardized protocol.
A Time Domain (TD) Optical Coherence Tomography (OCT) system working at 1300 nm was used in this study (Figure 3).
The system is based on an interferometer equipped with a scanning system in three dimensions. Using these scanners, different contours, surfaces or volumes of chondral articular surfaces can be obtained, used for quality and durability. The system provides the following modes of scanning:
Dimensional outline-in depth (A-scan), which provides a variation of chondral material reflectivity in depth;
Horizontally oriented surface (C-scan), at a certain depth that can be selected using a scanning device in subsurface; it provides a two-dimensional (2-D) distribution of chondral tissue;
Vertically oriented surface (B-scan), which provides a 2-D distribution of chondral material in a section in depth, which can be repeated at different orientations in the horizontal plane using two dual axis 2-D galvoscanners.
The size of the lateral aspect of the image, C-scan and B-scan can be adjusted continuously up to 10 mm;
Data analysis after OCT examination was performed by two independent examiners after a prior randomization of the patients. Degenerative changes of the cartilage structure were staged using the following classification: cartilage with normal laminar structure of the collagen fibers (grade 0), loss of the laminar appearance of cartilage (grade 1), and cartilage with surface irregularities (grade 2) (Figure 4).
All patients agreed to participate in this study. The Emergency Hospital Timisoara leadership agreed to conduct this study.