Intramuscular Tendon Injuries…..A cause for concern in Hamstring rehabilitation? Or not?!

After a little break from my blogs I have sat down to reflect upon a recent publication by @AvanderMade and colleagues which has been gaining some attention on social media, due to its conflicting findings with the initial work of @DrNoelPollock . It is also a topic that is fresh in my mind after I was kindly invited to a dissection morning with the students from @ChiSportsTherapy and was able to see just how prominent the tendon is to the Biceps Femoris anatomy.

Starting off with the work of van der Made et al. (2018) who structured their study in a prospective manner around the rehabilitation of two different cohorts based in both Holland and Qatar. Both cohorts completed a criteria-based rehabilitation program with the therapists and participants both blinded to the findings of the MRI scan. Within the retrospective work of Pollock et al. (2016) all athletes and therapists were provided with an MRI diagnosis at the time of rehabilitation, and progressions through rehabilitation were made with no formal return to play criteria set out.

Figure 1 – Taken From van der Made et al (2018)

Looking at the results of van der Made et al. (2018), a total reinjury rate of 19% was reported within the two cohorts at twelve-month follow up (Figure Two). The Dutch cohort had a much more significant rate of reinjury (28%) when compared to the Qatar cohort (12%) which will be discussed later. If we then compare these findings to those of Pollock et al. (2016) who found that there was a significant 60% reinjury rate within intramuscular tendon tears.

Figure 2 – Taken From van der Made et al (2018)

At first glance this study would appear significant and potentially more valid than the work of Pollock et al (2016) due to its large cohort and prospective study design. However the differences between the study design prevent direct comparisons being made in my opinion. Below is a summary of these differences that must be considered if we are going to make comparisons of the findings;

• The first significant difference between the two studies is the difference in cohort make up. The work of Pollock et al (2016) was performed within a track and field athletics setting where it could potentially be argued that integrity of the tendon is tested to a greater extent due to the all out explosive nature of the effort in the sporting demand, compared to the Dutch cohort of van der Made et al. (2018) who were predominantly from a competitive/recreational footballing setting.
• The prospective nature of van der Made’s work is also obviously a key difference from the retrospective study design of Pollock. By blinding the rehabilitation staff to the MRI findings there is a removal of any potential bias to treat based upon a preconceived belief that intratendinous injuries should be progressed at a slower rate. This cannot be proven in the work of Pollock, but could be an argument placed against it.
• Another key difference within the studies is that Pollock recorded exacerbations sustained prior to the athlete returning to full training. These exacerbations were not taken into account by van der Made, which is a significant flaw if looking at reinjury rate.

So what this probably means is that currently there isn’t enough strong evidence out there for us to base our clinical rehabilitation decisions upon. So what do we do if confronted with an intratendinous injury during the course of our daily practice? Well at this point until we have further research to suggest otherwise, we just keep it simple and treat what we see!

It seems that if we do work through a thorough rehabilitation program with clear objectives and multidisciplinary input then we are able to achieve satisfactory outcomes. It seems noteworthy that those participants in the Qatar cohort demonstrated a much lower reinjury rate (12%) than those in the Dutch cohort (28%). Could this be because they were professional athletes and had to commit to a minimum of five rehabilitation sessions a week? If so then maybe those of us working in professional football could look at intratendinous hamstring injuries with less fear than the initial work of Pollock et al. (2016) suggested.

Thanks as always for reading!