The influence of varus and valgus deviation on the contact area of patellofemoral joint in healthy knees

• Published in: BMC musculoskeletal disorders Vol. 24; no. 1; pp. 1 - 7
• Main Authors: Wang, Xiaomeng, Duan, Lisha, Liu, Huixin, Ge, Hailang, Dong, Zhenyue, Chen, Xiaobo, Xu, Chenyue, Ji, Gang, Kang, Huijun, Wang, Fei
• Format: Journal Article
• Language: English
• Published: London BioMed Central 31.10.2023; BioMed Central Ltd; BMC
• Subjects: Ankle; Arthritis; Body mass index; Cartilage; Cartilage (articular); Cartilage diseases; Contact area; Epidemiology; Evaluation; Femur; Hip; Internal Medicine; Kinematics; Knee; Knee flexion; Knee joint; Magnetic resonance imaging; Medicine; Medicine & Public Health; Methods; Musculoskeletal diseases; Orthopedics; Osteoarthritis; Patellofemoral joint; Patients; Physiological aspects; Rehabilitation; Rheumatology; Risk factors; Sports Medicine; Tibia; Variance analysis; Varus-valgus alignment; China; Patellofemoral joint; Contact area; Varus-valgus alignment; Knee flexion
• ISSN: 1471-2474; 1471-2474
• DOI: 10.1186/s12891-023-06976-9

Object Varus-valgus lower alignment is a risk factor for patellofemoral osteoarthritis, but malalignment alone affect not only the tibiofemoral joint but also the patellofemoral joint. The aim of the present study was to analyse the contact area of patellofemoral joint in varus alignment and valgus alignment of healthy subjects using magnetic resonance imaging. Methods Twenty-six healthy subjects with valgus lower limb alignment (Group I, n = 26) and twenty-six volunteers with varus lower limb alignment (Group II, n = 26) was performed. An MRI scan was used to capture and measure the patellofemoral joint articular cartilage contact area at different degrees of knee flexion (20°, 40°,60°) in passive movement. All subjects were categorized on the basis of the global limb alignment and mechanical alignment of the femur and tibia. Varus alignment is hip–knee–ankle angle ≥ 3°; and valgus alignment is hip–knee–ankle angle ≥ − 3°. To obtain medial facet contact area and lateral facet contact area for each slice, the length of each respective line of contact was multiplied by the 5 mm slice thickness. Results The overall joint contact area increased from 168.0 ± 20.5 mm 2 at 20° knee flexion to 334.4 ± 30.5 mm 2 at 60° knee flexion in group (I) The overall joint contact area increased from 178.0 ± 18.9 mm 2 at 20° knee flexion to 328.9 ± 27.2 mm 2 at 60° knee flexion in group (II) There was a significant difference in lateral facet contact area between group I and group II at 40° of knee flexion. There was significantly different in medial facet contact area between group I and group II at 20° and 40° of knee flexion. Conclusions Throughout the knee movement, the contact area on the lateral facet of the patellofemoral joint was greater in the valgus group. In the early phase of knee flexion, the contact area of the medial patellofemoral joint was larger in the varus group. Lower alignment is an important factor in patellofemoral joint degeneration.