Table 1.
Imaging parameters for MRI sequences.
Fig 1.
Reconstructed 3D MRI for knee cartilage and ROIs for quantification of cartilage thickness.
Knee 07 is a representative case in which the cartilage thickness increased in the PMF and MT regions. Knee 08 is a representative case in which the cartilage thickness decreased in the PMF and MT regions. P, patellar; AMF, anterior medial femoral; ALF, anterior lateral femoral; PMF, posterior medial femoral; PLF, posterior lateral femoral; MT, medial tibial; LT, lateral tibial. Note: The P, MT, and LT regions are divided into 9 sections for reference. The patella is inverted mediolaterally to show its relationship with the femur.
Table 2.
Patient population.
Fig 2.
The study included 21 knees that had no history of knee surgery and were receiving PRP injection for the first time.
Fig 3.
Reconstructed 3D MRI for knee cartilage and ROIs in Knee 01-10, representing the first half of the complete series.
The 21 knees are arranged in descending order of cartilage thickness in the PMF region. The red frame indicates cases in which the automatic ROI setting was inappropriate, so another ROI was copied. The blue frame indicates cases in which the automatic ROI settings for two areas were inappropriate, so one was set manually and the other was copied from it.
Fig 4.
Reconstructed 3D MRI for knee cartilage and ROIs in Knee 11-21, representing the second half of the complete series.
All 21 knees (across Fig 3 and Fig 4) are arranged in descending order of PMF cartilage thickness. Red frames indicate inappropriate automatic ROI settings requiring copying, while blue frames show cases where ROI settings for two areas were inappropriate, requiring manual setting of one area and copying to the other.
Fig 5.
Changes in cartilage thickness 6 months after PRP injection in the tibiofemoral joint.
For each region, the changes are shown in decreasing order, beginning with the greatest change. Positive values indicate thickening, while negative values indicate thinning. Green bars represent KL 0 and 1, while gray bars represent KL 3 and 4. The orange background indicates the range in which the absolute value of change is within 0.1 mm.
Fig 6.
Changes in cartilage thickness 6 months after PRP injection in the patellofemoral joint.
For each region, the changes are shown in decreasing order, beginning with the greatest change. Positive values indicate thickening, while negative values indicate thinning. Green bars represent KL 0 and 1, while gray bars represent KL 3 and 4. The orange background indicates the range in which the absolute value of change is within 0.1 mm.
Fig 7.
Proportions of cartilage thickness changes by threshold.
Changes in cartilage thickness 6 months after PRP injections were categorized using three thresholds. The change in cartilage thickness over 6 months is denoted as ΔThickness. Considering the variations with an absolute magnitude greater than 0.1 mm as changes exceeding the margin of error, ΔThickness > 0.1 mm is considered to indicate an increase beyond the detection threshold, -0.1 mm ≤ ΔThickness ≤ 0.1 mm is considered to be within the margin of error, and ΔThickness <-0.1 mm is considered to indicate a decrease beyond the detection threshold.
Fig 8.
Changes in KOOS 6 months after PRP injection.
For each subscale, the changes are shown in order, beginning with the greatest change. Positive values indicate improvement, while negative values indicate deterioration. Green bars represent KL 0 and 1, while gray bars represent KL 3 and 4. The yellow background indicates the range in which the value of change is below 10.
Fig 9.
Scatter plots showing the relationship between the change in cartilage thickness and changes in KOOS pain scores over 6 months.
Representative plots for the PMF and MT regions are shown. No correlation was found between the change in cartilage thickness and the change in KOOS pain score in either the PMF or MT regions.