This study is the first to investigate the relationship between the radiological characteristics and clinical evaluation of FCD/NOF and the physical activity level in children. In our study, we observed that FCD/NOF lesions occurred incidentally in 21.4% of patients. Despite the assertion in the existing literature that lesions are predominantly identified on radiographs obtained for reasons unrelated to the detection of such lesions, our study revealed that the most frequently reported symptom was pain, accounting for 49.9% of cases. Similarly, in a prevalence study, half of the patients with FCD had spontaneous pain complaints [7][5].
When complaints were compared between boys and girls, no significant difference was found between them, but pain at rest was seen to be more common in boys. The physical activity levels of children and adolescents were classified as either very inactive or moderately active, a finding that was consistent with that of previous published literature.[22] Paralel findings were found in a large-scale study conducted by Guthold, R et al., covering 1.6 million childern and young adolescents, stating that 81% of the students aged between 11–18 years (Boys: 77.6% / Girls: 84.7%) were not physically active [22, 23][20, 21]. A further noteworthy finding of the study was that, while the physical activity levels of boys and girls with FCD/NOF were similar, there was a decline in physical activity as Ritschl Stage increased. Moreover, physical activity was associated negatively to pain scores. Thus, pain is considered as a condition that limits physical activity. Similar to our findings, a study evaluating pain and physical activity bidirectionally in adolescents found that the experience of pain limits physical activity on a daily basis. In a study comparing adolescents with chronic pain and their healthy peers, physical activity was measured objectively via actigraphy, and it was found that those with pain had lower levels of physical activity as well as decreased physical functionality [24]. However, in adolescents with chronic pain, the pain intensity was lower at the end of the day in those with higher levels of physical activity [25]. Findings of our study showed that there is no relationship between the Ritschl stage and the pain scores, In our study, lesion size increased with increasing Ritsch stage. Based on this information, it can be considered that increasing lesion size is not associated with pain, as Emori et al. reported that lesion size is not associated with spontaneous pain.[7].
On the other hand, the use of technology may cause a decrease in physical activity because it hinders children's daily activities. In previous studies, physical activity was found to be low in children who spent long time on using technology [26, 27]. In our study, the majority of children with FCD/NOF had more than 2 hours of on screen time in both genders, but on screen time was not assocciated to physical activity level. Paralel results were obtained in the study conducted by Karaca et al., which showed that on screen time was not correlated with physical activity in children without any disease[28], and Nilsson et al. reported that increasing exercise time was not correlated to shortening TV watching[29]. An international study conducted by Melkevich et al., showed that on screen time is negatively correlated to physical activity in countries where the average physical activity level is high. However, across geographic regions and genders with generally lower levels of physical activity, it has been shown that there is no consistent association with levels of screen-based sedentary behavior spent more than 2 hours per day [30].
According to our radiological findings, Stage A lesion was the most detected lesion classified according to Ritschl's classification, which was consistent with the findings of the study conducted by Emori et al.[7]. Additionally, our study showed that size of FCD or NOF increases with the increasing stage according to Ritschl's classification, while Herget et al. Also reported that the size of the lesions increased with the increase in the stage of the lesions [6]. In contrast to the study of Herget et al. who reported an increase in age with increasing Ritschl stage, we did not find any significant difference between Ritschl stages according to age. Blaz et al. also agreed that the average age of patients increased with increasing Ritschl stage [4, 6], both studies include adult in addition to children in their study sample. Thus different results in our study might be due to the younger age group of patients and also using different imaging methods for evaluation.
In our study, 9 patients were in Stage B, while one of them had a pathological fracture, which is consistent with the literature stating that patients with Stage B lesions have an increased risk of suffering a pathological fracture. Similarly, Herget et al. reported pathological fractures in 6 out of 87 patients[12], while Emori et al., reported that fractures were detected in 2.1% of patients with Ritschl classification Stage B [5]. Moreover, 3 children had more than one lesion in our study which is also consistent with literature stating that 5–8% of patients have multiple lesions [6, 7, 31].
This study has several limitations that has to be stated; Firstly, the patients' exercise barriers, which might affect the phycial activity level, have not been questioned in detail. Moreover, some physical activity parameters such as intensities, type of exercise (i.e. aerobic and muscle and bone strengthening activities) has not been identified. Secondly; Children were also not evaluated regarding sleep duration and psychological impact. Finally;
Although we classified lesions according to Ritschl's classification, a longitudinal study that follows patients over the long term could show the progression of X-ray and MRI findings over time. The Ritschl staging system is based on the clinical course of the healing process, as the stage increases, the lesion is expected to mature and then heal. The progression of the Ritschl stage with increasing child age has been documented [6]. The absence of Ritschl stage D in our sample (because stage D cases over 18 years of age were not included in the study) and the small sample size can be considered as other limitations.
The first outcome of the research; The study revealed physical activity, radiological imaging and clinical status in children diagnosed with FCD/NOF. The clinical background of this pathology, known as "touch-free lesion" in the literature, was evaluated.
Secondly; The relationship between pain and other symptoms and physical activity was examined, and attention was drawn to physical activity affecting the growth and development of children.
It was determined that pain was the main complaint in half of the patients and was responsible for restricting the mobility, and thereby decreased physical activity in patients. In addition, as the Ritschl stage increased, physical activity decreased. Therefore, it is recommended to inform the child and the family about the decrease of physical activity and to provide support from experts when necessary.