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

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