Incidence and risk factors for medial tibial stress syndrome and tibial stress fracture in high school runners.
Yagi S, Muneta T, Sekiya I. Knee Surg Sports Traumatol Arthrosc. 2012 Aug 9. [Epub ahead of print]
Medial Tibial Stress Syndrome (MTSS), also known as ‘shin splints,’ is commonly seen in runners and can be a very frustrating and nagging injury. Tibial stress fractures (SF) are another significant injury that can potentially force athletes to take long periods of rest. Despite the high frequency of MTSS and the implications of SF, it is unclear what risk factors may be related to these conditions. Therefore, the authors of this study wanted to identify the incidence and also establish risk factors for these injuries. To do so, they performed a prospective study examining 230 high school runners in Japan for three years. The authors tallied the number of MTSS and tibial SF and examined the following risk factors: height, weight, body mass index (BMI), hip and ankle motion, straight leg raise, intercondylar and intermalleolar interval, Q-angle, navicular drop test and hip abductor strength. These measurements were done at baseline within four weeks of the student athlete entering school. All injury reporting was the responsibility of the school coach. The researchers were notified when an athlete could not train for seven days secondary to shin pain, and then the athletes were evaluated by the orthopedic clinic. The authors found a total of 102 athletes with MTSS (58 male, 44 female) and 21 athletes with SF (7 male, 14 female) over the three years of the study. BMI and internal hip rotation angle were significant risk factors for MTSS in females, while limited straight leg raise was a significant risk factor for SF in males. It is important to note that among females the BMI values were on the lower range of normal for those with and without MTSS (MTSS group ~19.3 kg/m2, uninjured group ~ 18.4 kg/m2). Second, female athletes with MTSS had an average hip internal rotation of 31.1 degrees compared with an average hip internal rotation of 25.5 degrees among uninjured female athletes. Finally, males with SF had an average straight leg raise of 60.0 degrees while uninjured males had a higher straight leg raise of 74.3 degrees. The authors did not discuss in detail the amount of training performed by each runner, simply stating that training frequency was not an external risk factor for MTSS or SF.
A lack of flexibility, joint range of motion, or muscle tightness may be important risk factors for sports injuries in general and this paper suggests that they may be risk factors for SF among males (i.e., limited straight leg raise) and MTSS among females (increased hip internal rotation). In addition to flexibility and range of motion concerns, a higher BMI was also a risk factor for MTSS among females and may correlate with a lack of conditioning, and therefore may place an athlete at greater risk for injury. However, 19.3 kg/m2 is not a high BMI which raises the question of whether there were other factors leading to more MTSS? For example, an interesting addition to this study would have been to screen for dietary calcium and vitamin D intake, and check to see if any of the runners were vitamin D deficient. There were a few advantages of this study. First, the authors used a large sample size with a good time interval. Also, they used running athletes as opposed to other studies which evaluated MTSS and SF among military personnel. However, it is unclear if we can use the results of this research study and apply it to our running programs based on possible differences in age, ethnicity and training styles? Lastly, can the results be used for other athletes besides runners? Do your sports medicine departments have a flexibility program and do you screen for flexibility problems as part of your pre-participation physical?
Written by: Jill R. Crosson DO, MBA
Reviewed by: Jeffrey Driban
Related Posts:Yagi S, Muneta T, & Sekiya I (2012). Incidence and risk factors for medial tibial stress syndrome and tibial stress fracture in high school runners. Knee Surgery, Sports Traumatology, Arthroscopy PMID: 22875369