The Evaluation of Medial Longitudinal Arch Morphology in Children With Spastic Diplegic Cerebral Palsy by Arch Height Index Measurement Method

Foot deformities are one of the most common orthopedic problems in patients with cerebral palsy(CP). Various methods have been proposed to evaluate foot morphology. Arch height index (AHI) measurement is a simple and quantitative method that can be applied in outpatient settings to evaluate the morphology of the medial longitudinal arch(MLA) of the foot. In this study, we aim to investigate the feasibility of AHI measurement in children with CP and, to identify other clinical findings that may be related to foot arch height determined by the AHI method.

Cerebral palsy (CP) is a posture, movement, and motor dysfunction that occurs as a result of non-progressive damage of the developing brain during the intrauterine period or early childhood. Foot deformities, including pes planus and pes cavus, are common in children with CP and deteriorate posture and mobility due to its progressive nature and accompanying pain. Spasticity, muscle imbalances, soft tissue changes, and subsequent skeletal disorders are blamed for foot deformities in patients with CP. Some methods such as foot posture index, navicular drop test, footprint methods, and radiological imaging have been described to identify and evaluate the MLA and foot/ankle posture. Arch height index (AHI) measurement is a novel method that evaluates especially medial longitudinal arch(MLA) morphology, with proven validity and reliability. It is essentially based on the measurement of the dorsum height and the length of the foot by using various caliper systems during varying degrees of load-bearing like sitting or standing. AHI measurement has some advantages over other methods. Measuring AHI during varying degrees of load-bearing such as sitting or standing allows us to quantitatively assess the mobility of the MLA. AHI measurement should be preferred in patients with foot sole skin disorders where footprint measurement methods are inefficient. Its results are not affected by some factors such as x-ray tube angle differences in foot radiography. It does not pose a risk of radiation exposure and is easy to apply. However, there is no data on the effectiveness of the AHI method in determining the MLA morphology in children with CP. The first hypothesis of this study is that AHI measurement results in patients with CP correlate with data obtained from standard foot radiographs. The second aim of the study is to investigate the relationship between MLA morphology and other findings such as joint range of motion and spasticity of lower extremity muscles in patients with CP. Patients with spastic diplegic cerebral palsy who were admitted to the Physical Medicine and Rehabilitation Department of our hospital will be evaluated in terms of eligibility criteria for the study. Eligible patients will be informed about the trial, and informed consent will be obtained from those who agree to participate. It was planned to recruit 24 subjects with a correlation coefficient of 0.8, a power of 0.90, and a margin of error of 0.05 to determine the correlation between AHI and quantitative foot radiography data. Demographic data, body mass indexes, physical examination findings including gait patterns, ankle and foot range of motion and tone of the certain lower extremity muscles of participants will be recorded. MLA morphology will be evaluated by foot radiographs and AHI measurements. The AHI measurement will be made both in the bipedal standing and in the sitting position with both feet calmly on the ground. AHI will be calculated by proportioning the height of the dorsum measured from the middle 1/2 of the total length of the foot to truncated foot length.