Just back from a great day doing the Run For the Kids with the family and this one caught my eye:
Peroneal tendinosis as a predisposing factor for the acute lateral ankle sprain in runners
Pejman Zia, Emir Benca, Florian Wenzel, Reinhard Schuh, Christoph Krall, Alexander Auffahrt, Martin Hofstetter, Reinhard Windhager, Tomas Buchhorn
Knee Surgery, Sports Traumatology, Arthroscopy; 19 Mar 2015
A painful episode in the region of the peroneal tendons, within the retromalleolar groove, is a common precipitating event of an acute lateral ankle sprain. A forefoot striking pattern is suspected to cause peroneal tendinosis. The aim of this study is to analyse the role of peroneal tendinosis as a predisposing factor for ankle sprain trauma in runners.
Fifty-eight runners who had experienced acute ankle sprain trauma, with pre-existing pain episodes for up to 4 weeks in the region of the peroneal tendons, were assessed clinically. Fractures were excluded by conventional radiography. An magnetic resonance imaging (MRI) scan had been performed within 14 days after the traumatic event and was subsequently evaluated by two experienced radiologists.
MRI revealed peroneal tendinosis in 55 patients (95 % of the total study population). Peroneus brevis (PB) tendinosis was found in 48 patients (87 % of all patients with peroneal tendinosis), and peroneus longus (PL) tendinosis was observed in 42 cases (76 %). Thirty-five patients (64 %) had combined PB and PL tendinosis. A lesion of the anterior talofibular ligament was found to be the most common ligament injury associated with peroneal tendinosis (29 cases; 53 %), followed by a lesion of the calcaneofibular ligament (16 cases; 29 %) and a lesion of the posterior tibiofibular ligament (13 cases; 24 %).
The results of this study reflect the correlation between peroneal tendinosis and ankle sprain trauma. Injuries of one or more ligaments are associated with further complications. A period of rest or forbearance of sports as well as adequate treatment of the peroneal tendinosis is essential to prevent subsequent ankle injuries, especially in runners. Modification of the running technique would also be beneficial.
The above clearly describes what they did and what they found and nothing in the methods jumps out at me as being a problem. There were a few statements in the paper that needed to be better sourced. For example, the statement in the abstract: “A forefoot striking pattern is suspected to cause peroneal tendinosis“. There is no evidence or data to support that, though my own clinical experience would support it (but that is just a collection of anecdotes) and in midfoot/forefoot striking you do use the peroneal muscles more, so it does make sense that midfoot/forefoot does increase the risk for it (but that is just biological plausibility); so it probbaly is the case that it is correct, but you need to careful in qualifying such statements as such and not state them as fact.
I was fascinated at the correlation between symptoms of peroneal tendinosis (which I wrote about here) and an acute ankle sprain. Acute ankle sprains in runners are not very common and without looking up any epidemiological studies, I am guessing that they make up less than 1-2% of injures in runners, so for the above study to recruit 58 is pretty impressive! Of those 58, 55 of them had shown signs of peroneal tendinosis on MRI and 48 of them had related a history of peroneal tendinosis prior to the ankle sprain. Peroneal tendon problems are also not that common in runners, so given that most of those with the ankle sprain had it is pretty impressive finding. Now, that is why this study caught my eye!
The important thing here is that this is a correlation. Correlation is not causation. Peroneal tendinosis could cause an ankle sprain, but you can not conclude that from the methods used in this correlation study.
What was lacking in the write up of this study was a deeper discussion of the potential mechanisms. It could well be that there is some sort of neuromusculer or proprioceptive problem as a result of the tissue damage in the peroneal tendinosis that predisposes to the ankle sprains. It could also be that both the peroneal tendinosis and the acute ankle sprain share similar risk factors. A possible candidate here (as mentioned above) is forefoot/midfoot striking. I was disappointed that the authors did not consider what I would like to suggest is a common risk factor: lower supination resistance. I already talked about our correlation study that linked a lower supination resistance to peroneal tendonitis and also linking it to recurrent ankle sprains here. Again, these were correlational studies, but it does make intuitive sense that if the force to supinate or invert the foot is low, then of course, the peroneal muscles are going to be working a lot harder (ie potential risk for peroneal tendinosis) and its also going to be a lot easier to go over and sprain the ankle.
Unfortunately, even the title of the paper implies that the peroneal tendinosis predisposes to the ankle sprain (and it might) and does not consider that it might not, but they both share a common risk factor (ie that is why they correlate).
What ever the mechanism is this does show that we really need to treat peroneal tendinosis, especially if it is at a pre- or sub-clinical level and either manege it or deal with the risk factors to prevent it going on to an acute ankle sprain.
As always, I go where the evidence takes me until convinced otherwise… and this is a really neat piece of correlational evidence. Don’t you love it when a plan comes together?