Our study focused on addressing the association between elevated (BMI) and (ACL) injury, understanding the association between these variables is highly important specially in our population as the overall prevalence of obesity Saudi Arabia is around 35.6%, and the overweight is 36.9% that makes 72.5% of population are either overweight or obese (10). Surprisingly, our study showed that the injured patients were obese and overweight around (30%) and (40%) respectively, which account for 70% of the total patients.
Thein et al reported that increased BMI in both genders is associated with elevated prevalence of knee injuries but was more significant in female subjects with respect of having more associated meniscal and ligamentous injuries . However, most of the participants in this study were males accounting for 98.3%, while the female accounts for 1.7% of subjects. Furthermore, in our study, there was no significance association between the different BMI groups and gender (P-value: 0.220).
In our study, obese patients were more prone to develop knee injuries compared to normal BMI patients with a p value of (0.004). There was a significant difference in the reinjury rate, which was significantly less in normal BMI group with a P-value of (0.029). The risk of ACL tears and particularly combined ACL tears were significantly higher across obese patients as well as overweight patients with a p value of (0.001). AlJassir et al study showed that elevated BMI is not a risk factor for developing non-contact ACL injury with a p value of (0,697), however, they were not sure whether the BMI was changed time of injury and the time of surgery .
A recent systematic review showed that the non-contact injuries in normal BMI subjects account for 49%; while in elevated BMI subjects, the non- contact injuries reach 40%, which indicates no significance difference between the two groups . However, regarding to the mechanism of injury; Ballal et al reported that there is no significance difference between normal (BMI), overweight and obese. However, this study also showed that there is insignificance difference in the mechanism of injury between the three groups (P- value: 0.59) .
Our research focuses on the important role of elevated BMI and its positive relationship to ACL injury. BMI is one of the modifiable factors, so understanding the relationship between these variables will give us an opportunity to improve the prevention strategies of ACL injuries. According to Bojicic et al, it has been shown that subjects with elevated BMI had higher risk to develop ACL injuries. They looked at BMI as a modifiable risk factor and posterior tibial slope as non-modifiable risk factor and concluded that the BMI contributes in exacerbation of the positive correlation between posterior tibial slope and ACL injury risk. And their suggestions were toward the athletes who are recommended to increase their weight should decrease their weight as an effective way to decrease their risk of developing ACL injury . Derraik et al reported an association between patients with elevated BMI and the progressive decrease in physical functions, therefore such a deficit can include patients who suffer from orthopedic diseases such as ACL injuries .Identifying and understanding the risk factors and the mechanism of ACL injury are of great importance for the patients and clinician as it helps to design neuromuscular training programs for athletes . Our study showed that patients with elevated BMI had higher risk for developing ACL tear. Moreover, BMI has been showed to contribute to exacerbation of the positive correlation between elevated BMI and risk of ACL tears.
The limitation of our study, BMI was only measured at time of admission to the hospital and may not indicate the true BMI measure at time of injury.
Understanding the association between elevated BMI and ACL injury is important in implementation of the appropriate preventive measures. Recent literature suggests having an elevated BMI is a modifiable risk factor for ACL injury. Many questions remain unanswered, including the type of body fat mass versus the lean and how much is the hazardous amount of weight gain, all these questions could be the target of future researches .