Anthropometry of the medial femoral condyle in the Chinese population: the morphometric analysis to design unicomparmental knee component

Abstract

Background This study aimed to assess the radii of the distal and posterior articular surfaces of the medial femoral condyle in a Chinese population and provide detailed parameters of the knee joint for the future design of UKA components. Methods This study included 500 consecutive Chinese patients who underwent knee MRI from Jan 2019 to Jan 2020. The two most appropriate circles were used to reveal the distal and posterior joint surfaces in the sagittal plane of the MRI images. The radius of the circle representing the distal articular surface in the sagittal plane was measured as R1, and the radius of the posterior articular surface was measured as R2. The distance between the centers of the two rotation circles was recorded as d. An independent t test was used to compare the differences between men and women. The Pearson correlation coefficient was calculated to analyze the correlation between R1 and R2. SPSS v19.0 software was used for statistical analysis. Results The average values of R1, R2, R1/R2 and d were calculated. Scatter plots were constructed to show the trend of changes in the radius of the distal and posterior articular surfaces of the femoral condyle. R1, R2 and d differed significantly between men and women (p < 0.05). Correlation analysis showed that R1 was positively correlated with R2 (r = 0.61, p < 0.05). Conclusions The data of the radii of the distal and posterior articular surfaces of the medial femoral condyle were provided. In the UKA design, the relationships between the radii of the distal and posterior articular surfaces should be taken into account.

Intraoperative sensor technology quantifies inter-prosthesis pressure for predicting lower limb alignment after Oxford unicompartmental knee arthroplasty

“…The inter-prosthesis pressure is minimal at deep flexion of the knee joint, increases gradually as the joint is extended, reaches a peak at 20 °-45 °, and further decreases at full extension. This may be due to the single-radius design of the Oxford UKA prosthesis, while the radius and center of the human femoral condyle flexion-extension articular surface are not the same (Lu et al, 2021). After installation of the prosthesis, the spherical surface of the single-radius femoral prosthesis will partially exceed the original articular surface when the knee is flexed to a certain degree (probably 20 °-45 °), so there may induce an increase in the inter-prosthesis pressure in the middle of flexion.…”

Three-dimensional morphometric differences of resected distal femurs and proximal tibias in osteoarthritic and normal knees

“…An appropriate prosthesis size that matches the resected bony surfaces is considered a crucial factor for success in total knee arthroplasty (TKA) [ 1 , 2 ]. If the prosthesis underhangs the resected surface of the bone, it may cause early subsidence and loosening of the prosthesis, whereas an overhang may cause residual pain, poor knee flexion, and decreased functional results [ 3 , 4 ].…”

Balancing in Unicompartmental Knee Arthroplasty: Balancing in Flexion or in Extension?

“…Since the percentage of non-worn distal femurs in advanced knee OA is <5%, it assumes the risk of overindication. In the rare cases where it is, the wear is not volumetrically significant and therefore does not functionally matter with respect to the surgical technique in question [10][11][12].…”