The articular cartilage plays an exceedingly significant role in various aspects of the elbow joint, including flexion, extension, rotation, load-bearing, and force transmission. Changes in the anatomical parameters of the cartilage not only alter its biomechanical structure, leading to discomfort but also have a profound impact on elbow joint surgeries and articular anatomical reconstructions. Previous research has primarily focused on the two-dimensional "planarization" assessment of cartilage, lacking spatial-specific studies of the articular cartilage. Additionally, there is a lack of research concerning the distribution of articular cartilage in the bilateral elbow joints of young to middle-aged individuals. Consequently, the absence of evidence in selecting appropriate control templates for articular cartilage in patients' elbow joints contributes to uncertainty in current clinical treatments.

To evaluate the three-dimensional distribution of articular surface cartilage of distal humerus, compare the difference of articular cartilage distribution of bilateral elbow, and preliminarily analyze the risk factors affecting individual differences of articular cartilage.

The 3D-MRI scans of bilateral elbow joints from patients who visited our hospital between January 2021 and December 2022 were collected in our study, excluding those with osseous or cartilaginous structural abnormalities. A total of 36 subjects, comprising 17 females and 19 males, with an average age of 34.8 years (ranging from 23 to 45 years), were included, with 26 right-hand dominants. Subjects with no evidence of osteoarthritis were enrolled. Demographic information and imaging data of the enrolled subjects were collected. In DICOM format, the imaging data were transferred to MIMICS 21.0 software to establish a corresponding three-dimensional coordinate system. With the sagittal plane images perpendicular to the subchondral bone, measurements of cartilage thickness were conducted at multiple locations. The study aims to evaluate the distribution of articular cartilage thickness on the normal distal humeral joint surfaces in young to middle-aged individuals, assess the consistency of bilateral articular cartilage thickness, and analyze the factors influencing stress articular cartilage thickness.

On the dominant side, the distal humeral articular cartilage was thickest at the 7 o'clock position of the humeral trochlea, measuring (1.54±0.39) mm, and thinnest at the 2 o'clock position of the lateral aspect of the capitellum, measuring (0.09±0.31) mm. On the non-dominant side, the cartilage was thickest at the 6 o'clock position of the lateral aspect of the capitellum, measuring (1.49±0.29) mm, and thinnest at the 11 o'clock position of the medial aspect of the trochlea, measuring (0.03±0.16) mm. A statistically significant difference existed between the cartilage distribution's thickest and thinnest points (dominant side: P< 0.01, non-dominant side: P< 0.01). The most remarkable difference in thickness between bilateral articular cartilage was (0.17±0.38) mm, showing no clinically significant statistical difference. Wilks' canonical correlation analysis revealed no statistically significant correlation between articular cartilage thickness within the joint surface domain and age, gender, dominant side, or occupational type (P>0.05) .

In the normal young and middle-aged population, there are differences in distal humeral articular cartilage thickness distribution. No significant differences are observed in the thickness distribution of articular cartilage between both sides of the joint. Additionally, articular cartilage thickness does not correlate significantly with age, gender, dominant side, or occupational type.