The Relationship of the Medial Longitudinal Arch Height With Clinical Features of Knee Osteoarthritis

The ratio of the dorsum height of the foot (measured in the middle of the total foot length) to truncated foot length, while bipedal standing. Normal values have been reported to be approximately 0.338 ± 0.031 to 0.343 ± 0.033 in college-aged women. Higher values represent the increased medial longitudinal arch height of the foot (e.g. pes cavus) while lower values are related to pes planus.

The ratio of the dorsum height of the foot (measured in the middle of the total foot length) to truncated foot length, while sitting with feet calmly on the ground. Normal values have been reported to be approximately 0.355 ± 0.031 to 0.369 ± 0.034 in college-aged women. Higher values represent the increased medial longitudinal arch height of the foot (e.g. pes cavus) while lower values are related to pes planus.

Arch Height Flexibility will be calculated by the [(arch height while sitting - arch height while standing) / 0.4 x body weight] x 100 (m/kN) formula. Higher values represent the more flexible medial longitudinal arch structure.

It is a radiological grading of knee osteoarthritis with a value between 0 to 4. Medial and lateral tibiofemoral compartments are evaluated on weight-bearing anteroposterior knee radiograph in terms of joint space narrowing, subchondral periosteal sclerosis, subchondral cyst and osteophytic formations. Zero means no radiographic evidence of osteoarthritis, while 4 indicates advanced knee osteoarthritis.

It is the angle, measured on a weight-bearing, full-length anteroposterior lower limb radiograph, between the anatomical axes of the femur and tibia. The normal value of the anatomical tibiofemoral angle is between 4 to 6 degrees of valgus. A higher positive value will indicate more valgus posture of the knee, while lower or negative values will be related to varus deformity.

It is the angle, measured on a weight-bearing, full-length anteroposterior lower limb radiograph, between the lines drawn from the femoral head to the femoral intercondylar notch and from the tibial interspinous point to the tibial mid-plafond. The mechanical tibiofemoral angle is approximately 1-1.5 degrees of varus for a knee in normal alignment. In this study, to ensure consistency with the anatomical tibiofemoral angle values, the direction of angulation will be noted as a positive or negative value for the valgus or varus, respectively.

WOMAC is a specific, valid and reliable tool for measuring disability in the knee and hip osteoarthritis. It includes 24 questions under three sub-domains: pain, stiffness, and physical function. Each question is scored on a Likert scale as 0=none, 1=mild, 2=moderate, 3=severe, and 4=extreme. The total score is defined by the [(sum of the scores)/96]x100 formula and ranges from 0 to 100. Higher scores indicate increased disability due to more severe pain, stiffness and impaired physical function.

Participants are asked to mark the severity of their right and left knee pain in the past month on a 100 mm horizontal line; where point zero represents "no pain" and point 100 represents "the most severe pain possible". The result is noted in millimetres by measuring the distance from the "zero" to the marked point. Increasing values represent higher pain intensity.

Flexion and extension range of motions will be measured using a goniometer regarding the neutral zero method for both knees. Decreased values represent a limited range of motion of the knee joint.

The duration of knee pain leading to hospital admission will be noted.