The Effect of Lower Extremity Rotational Profile on Postural Control, Muscle Strength, Functional Capacity and Lower Extremity Function in Children With Generalized Joint Hypermobility

Hip internal and external rotation angles measurement, hip range of motion evaluations will be performed. Measurements will be performed using a universal goniometer. The children will be positioned in the prone position with their knees flexed 90° and placed on the edge of the bed. The tuberositas tibia will be chosen as the pivot point of the goniometer, and the movable arm will be aligned with the tibial crista. The fixed arm will be placed perpendicular to the floor and the movable arm will be guided by the tibial crista. During hip rotation, it will be ensured that the hip remains stable and the movement occurs only in the hip joint.

The Craig's (Ryder) test, also known as the 'Trochanteric Prominence Angle Test', will be performed on the children included in the study according to the following protocol. The children will be placed in a prone position. The physiotherapist stood on the opposite side of the hip to be tested. The hips of the children will be placed in the extension position and the knee on the side to be tested will be held in the 90° flexion position. The physiotherapist palpated the trochanter major with the left hand and internal rotated the hip with the right hand. At the point where the trochanteric process will be most prominent, the angle between the tibia and the vertical plane will be measured using a goniometer and the femoral anteversion angle will be recorded.

Foot/thigh angle assessment will be performed by measuring the angle between the long axis of the femur bone and the foot with a goniometer in the prone position. One arm of the goniometer will be placed parallel to the long axis of the femur, while the other arm will be placed so that it passes through the 2nd and 3rd metatarsals. Normally, the thigh-foot angle should be in external rotation between 10-15°. In young children, this angle can be considered normal up to 30°. A decrease in the thigh-foot angle will indicate internal tibial torsion (expressed as a negative value), which is the internal rotation of the tibia. In this case, there is an abnormal internal rotation of the tibia. If the measured foot-thigh angle exceeds 30°, it is considered to be external tibial torsion (external rotation of the tibia).

The heel bisector line test is an evaluation method that helps diagnose metatarsus adductus. During the test, the child will be placed in the prone position with the heel between the physiotherapist's fingers. Then, the midpoint of the lines drawn from the malleoli will be determined. From this point, a perpendicular line will be drawn from the heel to the toes along the foot axis with the help of a goniometer. Normally, this line should end between the 1st and 2nd toes. If the line ends at the 3rd, 4th or 5th toes, this may indicate the presence of metatarsus adductus.

The Q-angle is defined as the angle formed between an imaginary line connecting the anterior superior iliac spine of the pelvis to the midpoint of the patella and the proximal projection of the line from the tibial tubercle to the center of the patella. The child will first be placed in a supine position with legs extended and muscles relaxed, and the midpoint of the patella will be marked with a colored pencil. Then, the goniometer will be placed at the midpoint of the patella and care will be taken to fix the movable arm so that it points to the anterior superior iliac spine and the fixed arm so that it follows the tibia and the angle between the two will be recorded. The measurement will be recorded in two different positions, lying and standing. Q angle between 10-15° in boys and 15-20° in girls will be considered normal.

The navicular drop test is commonly used in clinics to assess pes planus. It will begin with the child sitting, feet flat on the floor, and no weight bearing. The navicular tubercle will be palpated and marked first, then the distance from the tubercle to the floor will be measured. The child will then stand with equal weight on both feet and the distance will be measured again. Measurements will be taken bilaterally and recorded in millimeters. The difference between the weighted and unweighted measurements will indicate foot posture: 5-9 millimeters is normal (neutral), 10 millimeters or more will indicate pronation (inward rotation), and 4 millimeters or less will indicate supination (outward rotation). This test is important for assessing the degree of pes planus.

The foot progression angle will be used as an important parameter in determining potential disorders and alignment errors in the child's walking pattern by reflecting the rotational relationships between the femur, tibia and foot. For this measurement, two chairs will first be placed opposite each other with a distance of 2 m between them. Then, the child will be asked to sit on the chair. In the sitting position, the middle of the heel and the second toe will be marked with colored paint. After the marking, the child will be asked to walk naturally on a flat surface to the chair opposite. The child will stand up from the sitting position and walk approximately 5-6 steps on a flat surface to the chair opposite. Then, the child will be asked to sit on the chair opposite and clean the paint off his foot. This colored marking will be made in a way that will create the child's walking traces. When the child finishes walking, these traces will be measured in degrees using a goniometer.

The Thomas test will be performed to evaluate shortness/tightness in the hip flexor muscle group, especially in the iliopsoas muscle. The child will be placed in the supine position, the lumbar spine will be fixed and the assessment will begin. During the test, while the assessed hip is in knee extension, the opposite hip and knee will be passively flexed by the physiotherapist, and the hip movement of the assessed side will be observed during this time. The Thomas test will be recorded as negative if no flexion movement is observed in the assessed hip. In the presence of shortness/tightness, the assessed hip is seen to be flexed, and in this case, the Thomas test will be recorded as positive.

The popliteal angle test will be used to evaluate shortness or tightness of the hamstring muscles. The hip and knee will be placed in a 90° flexion position while the child is in the supine position. While the physiotherapist passively moves the knee joint towards extension, the popliteal angle will be measured using a goniometer. While one arm of the goniometer is placed parallel to the lateral surface of the femur, the other arm is held parallel to the fibula head and the angle will be measured. The knee joint will be extended until it encounters resistance and the angle between the tibia and the vertical plane will be recorded as the popliteal angle.

Gastrocnemius assessment will be evaluated with the Silfverskiold test for all children participating in the study. The assessment will be performed bilaterally in supine positions where the child does not bear weight on their feet. The knee joint will be in full extension and 90° flexion, the subtalar joint will be in a neutral position, and the ankle dorsiflexion will be measured with the fixed arm of the universal goniometer on the fibula shaft and the mobile arm following the fifth metatarsal shaft. The measured angles will be recorded in degrees (°). Passive ankle dorsiflexion of ≤ 10° with the knee extended and a minimum of 10° increase in dorsiflexion with the knee flexed will be considered as isolated gastrocnemius muscle shortness.

The Ober test will be performed to measure the length of the iliotibial band. Both the Ober test and the modified Ober test are widely used and accepted tests to assess iliotibial band length. During the test, the child will be placed in a supine position with the lower leg slightly bent at the hip and knee. The upper leg will be in 90° flexion of the knee. Once positioning is complete, the physiotherapist will hold the ankle of the upper leg with one hand and stabilize the hip with the other hand. The leg will then be abducted and the knee extended and the leg moved until the femur is in line with the body. Finally, the thigh will be allowed to fall towards the surface in this plane and the result of the test will be judged by the amount of adduction of the hip. If the knee hangs in the air, the test is positive. If the knee falls, the test is negative

The Duncan-Ely test will be used to evaluate the shortness and tightness of the rectus femoris muscle. While the child is lying in the prone position, the hip will be fixed with one hand by the physiotherapist and the hip and knee will be kept in extension. In this position, the knee joint will be passively flexed in order to stretch the rectus femoris muscle on the tested side. If no shortness or tightness is observed in the rectus femoris muscle on the same side during the test and hip extension is maintained, the Duncan-Ely test will be recorded as negative. However, when the knee is flexed and a flexion movement is observed in the hip, the test will be recorded as positive.

The Sit-Reach test will be used to evaluate the flexibility of the hamstring and lower back muscle groups. The S\&R Sit and Reach® table will be used for this test. The child will sit in front of the table with dimensions of 55 centimeters long, 35 centimeters wide, and 30 centimeters high, and his/her feet will be positioned on the foot surface of the table. The child will be asked to place his/her hands on top of each other and stretch forward in a slow and controlled manner, bringing the ruler on the table forward. He/she will be asked to wait 1-2 seconds at the farthest point without stretching forward or backward. Scoring will be done according to the ruler on the table. (On this table, the child's ability to bring the ruler to the tips of his/her toes corresponds to 23 centimeters). The test will be repeated three times for each child to ensure reliability, and the highest value will be recorded in centimeters.

Postural stability, limits of stability, and sensory integration of balance will be assessed using the Biodex Balance System®. Biodex Balance System is a validated and reliable device used to evaluate postural stability, limits of stability, and fall risk. It consists of a balance platform, arm supports, a screen, and a printer. The platform can be set to static or dynamic mode (12 levels; level 12 = most stable, level 1 = least stable with up to 20° movement in all directions). Prior to testing, children will be informed about the procedures. The heel and toe positions will be recorded based on medial-lateral (B-J), anterior, and posterior (1-21) axes. Arm support and screen height will be individually adjusted. Child-specific posture and identification data will be entered into the system. Three tests will be performed: postural stability, limits of stability, and sensory integration of balance.

Muscle tests will be performed using the MicroFET 2 digital hand dynamometer according to the device manual. The measurement will be performed in supine, prone, side-lying and sitting positions by preventing compensatory movements. During the test, the arms will be positioned so that they will not receive power from anywhere on/to the side of the body. Measurements will be performed bilaterally. While the child to whom the test is applied is expected to perform the requested movement with all his/her strength, the evaluating physiotherapist will apply resistance in the opposite direction in proportion to the strength. During the evaluation of the same muscle, a 30-second break will be given between repetitions, and a five-minute rest will be given before moving on to the test for a different muscle. Isometric muscle strength of the Iliopsoas, Gluteus Maximus, Gluteus Medius, Quadriceps, Hamstring, Tibialis Anterior, and Gastrosoleus muscles will be evaluated.

"The 6MWT will be done on a flat 30-meter track marked every 3 meters, with clear start and finish lines. Before the test, the child rests 15 minutes while contraindications will be checked. If none, blood pressure, oxygen saturation, pulse, and Borg scale scores for dyspnea and fatigue will be recorded. Medications taken will be noted. The child will be instructed to walk at their own pace for 6 minutes, allowed to stop or rest, and continue until test is over is announced. The test will start with test is started and end with test is over. The timer will run continuously even if paused. The test ends if chest pain, severe breathlessness, cramps, unsteadiness, sweating, pallor, or oxygen saturation \<85% occurs. Afterward, the child will be sits and post-test vitals and Borg scores will be recorded. Distance walked and any complaints during the test will be noted."

The Lower Extremity Functional Scale will be used to evaluate the functional ability of the entire lower extremity in individuals with musculoskeletal disorders. This scale will question the difficulty experienced in various daily activities due to the problem in the lower extremity with 20 items. Each item will be scored between 0-4 on a Likert scale (0=extremely difficult/too difficult to do the activity; 4=not difficult at all). The total score varies between 0-80 and the higher the score, the higher the functional level. A validity and reliability study has been conducted for the Turkish version of the scale to be used in evaluating lower extremity functions.

"The Visual Analog Scale is a simple and reliable tool that is widely used to assess subjective experiences such as pain. It consists of a 10 cm horizontal line with one end indicating no pain and the other end indicating worst pain imaginable. Individuals will mark the point that reflects their perception of intensity, which will then be measured in millimeters or centimeters to obtain a numerical score. Higher values will indicate greater severity. The Visual Analog scale is valid and reliable in a variety of populations and conditions, including musculoskeletal pain."

All children's gender, age, body weight, height and dominant side information will be recorded before clinical evaluations. The body mass index (kilogram/meter2) of the child will be calculated and recorded with the recorded body weight (kilogram) and height (meter) values.

Dorsiflexion range of motion with the knee joint in full extension and 90° flexion, the subtalar joint in a neutral position, the ankle dorsiflexion will be measured with the fixed arm of the universal goniometer on the fibula shaft and the mobile arm following the fifth metatarsal shaft. The measured angles were recorded in degrees (°). Measurements will be made bilaterally.

Leg Length Measurement, the child will be placed in a supine position. The legs will be positioned in extension and the muscles will be relaxed. The physiotherapist will measure and record the child's right leg length from the SIAS bone to the medial malleola with a flexible metal tape measure. Measurements will be made bilaterally.