A number of studies have looked at risk factors for medial tibial stress syndrome. I have blogged about a couple of recent ones here and here. When there are enough prospective studies on a topic, there is time for a meta-analysis and systematic review to pool all that data. Here is a new one on medial tibial stress syndrome:
Risk factors for medial tibial stress syndrome in physically active individuals such as runners and military personnel: a systematic review and meta-analysis
Karrie L Hamstra-Wright, Kellie C Huxel Bliven, Curt Bay
Br J Sports Med; Online First
Medial tibial stress syndrome (MTSS) is a common injury in runners and military personnel. There is a lack of agreement on the aetiological factors contributing to MTSS, making treatment challenging and highlighting the importance of preventive efforts. Understanding the risk factors for MTSS is critical for developing preventive measures. The purpose of this systematic review and meta-analysis was to assess what factors put physically active individuals at risk to develop MTSS. Selected electronic databases were searched. Studies were included if they contained original research that investigated risk factors associated with MTSS, compared physically active individuals with MTSS and physically active individuals without MTSS, were in the English language and were full papers in peer-reviewed journals. Data on research design, study duration, participant selection, population, groups, MTSS diagnosis, investigated risk factors and risk factor definitions were extracted. The methodological quality of the studies was assessed. When the means and SDs of a particular risk factor were reported three or more times, that risk factor was included in the meta-analysis. There were 21 studies included in the systematic review and nine risk factors qualified for inclusion in the meta-analysis. Increased BMI (weighted mean difference (MD)=0.79, 95% CI 0.38 to 1.20, p<0.001), navicular drop (MD=1.19 mm, 95% CI 0.54 to 1.84, p<0.001), ankle plantarflexion range of motion (ROM; MD=5.94°, 95% CI 3.65 to 8.24, p<0.001) and hip external rotation ROM (MD=3.95°, 95% CI 1.78 to 6.13, p<0.001) were risk factors for MTSS. Dorsiflexion and quadriceps-angle were clearly not risk factors for MTSS. There is a need for high-quality, prospective studies using consistent methodology evaluating MTSS risk factors. Our findings suggest that interventions focused on addressing increased BMI, navicular drop, ankle plantarflexion ROM and hip external rotation ROM may be a good starting point for preventing and treating MTSS in physically active individuals such as runners and military personnel
This was a formal systematic review that pooled data from a number of studies and concluded that the main risk factors for MTSS were:
- higher BMI
- more navicular drop
- more ankle plantarflexion
- greater hip external rotation
It is good to see systematic reviews and meta-analyses focusing on one specific pathology and not just ‘injuries’ in general. What is a risk factor for one injury may not be a risk factor for another injury. For example the most recent meta-analysis and systematic review of risk of injury from “overpronation” concluded that it was only a small, but still a statistically significant risk factor. The above study found it was a risk factor for MTSS (ie navicular drop). One possible reason that “overpronation” was only a small risk factor for injuries in general is that it is probably not a risk factor for some injuries and is probably a risk factor for other injuries, but when you pool the data, its either not a risk factor or, in the case of the most recent analysis, a small risk factor.
While everything I can see that was done in conducting this meta-analysis and systematic review are correct and technically there is nothing I should have an issue with on that basis, there are some issues I do have, but are more due to the nature of these studies in general and not specifically the one above:
The biggest problem with these prospective risk factor studies, as important as they are, is that they only look at the risk associated with the factors that they are investigating. No study can investigate them all, and even if they tried, the more potential risk factors that are incorporated into the study the more likely an association will show up by chance. Additionally, there are also many “pet” risk factors that clinicians (or cults) have that may or may not be real risk factors which do not get included in many, if any, of the studies. For example, in the context of the above study on medial tibial stress syndrome is the role of bending moments of the tibia as a risk factor. It is a current ‘hot’ hypothesis that the management of appears to be getting good clinical results (I wrote about it here and here). I am the first to admit that there is no prospective risk factor study on the bending moments nor is there any clinical trial of the two different interventions that can be used to manage it compared to placebo or the natural history, but it does have some sound theory and is biologically plausible and it is consistent with what evidence there is. A lot of clinicians are applying this concept and they are all claiming that it works well. My point in mentioning this is to point out the limited clinical application that studies like the above actually have when there are alleged risk factors that clinicians are addressing, but they are not included in the epidemiological risk factor studies. This limits the clinical usefulness and applicability of these types of studies until what clinicians think are important get included.
As an aside, even if a prospective study did show that the bending moments was a risk factor for MTSS, it would have been excluded from the above meta-analysis and systematic review as they only included risk factors that were mentioned in three or more studies. This further limits the clinical applicability of the review.
As always: I go where the evidence takes me until convinced otherwise … and as good as this analysis was, its not going to change the clinical practice of addressing the factors that have not been included in the prospective studies…….. Houston, we have a problem.
Hamstra-Wright, K., Huxel Bliven, K., & Bay, C. (2014). Risk factors for medial tibial stress syndrome in physically active individuals such as runners and military personnel: a systematic review and meta-analysis British Journal of Sports Medicine DOI: 10.1136/bjsports-2014-093462