Acute Muscle Injuries

“This special edition about muscular injuries provides current knowledge to orthopaedic surgeons. Acute muscular injury is the most frequent trauma encountered by sport physicians and surgeons. These injuries must be well understood: physiology, biomechanics, healing process, but also epidemiology, nutrition, and psychology may explain not only the onset of the injury but also how to manage these lesions. The consequences of these lesions are sometimes dramatic […] After a global and transversal approach, ten chapters cover different localizations of acute muscle injuries. The chapter will address the definition of the injury, clinical aspects, complementary exams, preoperative findings, assessment and therapeutic options. […] injuries are described from trauma mechanism, physical examination findings and diagnostic and treatment algorithms towards rehabilitation programs and full return to sports. The book is structured in a fashion that allows people to use it as a reference manual. Therefore, this book is directed to orthopaedic surgeons, sports medicine physicians, physiotherapists, general practitioners, sports managers, athletes and coaches.”

I found it a bit funny that the book was directed to ‘athletes and coaches.’ The passage below provides part of the reason why:

“The plantaris muscle originates from the supracondylar ridge of the lateral femoral condyle and courses toward the posteromedial side of the lower leg. It inserts just medial of the Achilles tendon on the calcaneus. The plantaris muscle is located between the more superficial gastrocnemius and the deeper soleus muscle. The general function of this muscle group is plantarflexion of the ankle [29]. The soleus muscle originates from the proximal part (±1/2) of the posterior tibia along the soleal line and the proximal part (±1/3) of the posterior fibula. The gastrocnemius muscle spans three joints: the knee, ankle, and subtalar joint. The gastrocnemius is a bipennate muscle; the lateral head originates from the posterior aspect of the lateral femoral condyle, whereas the medial head arises from the medial femoral condyle. […] Repairs of distal ruptures generally focus on restoring the insertion of the distal biceps tendon on the radial tuberosity, although tenodesis to the brachialis tendon has also been reported [11,27]. The tendon and muscle can generally be mobilized to facilitate anatomic repair in acute cases, while augmentation is occasionally required in more chronic situations [45]. Repair was traditionally performed through an extensile Henry approach to the anterior elbow [53]. A high complication rate led Boyd and Anderson to develop the classic two-incision approach to anatomic repair [6].”

If you fail to see where I’m heading, combine the above stuff with this link (Danish link). No statistics seem to exist on this stuff, but the manager of the Danish union of soccer players says in the article that he estimates that only half of the professional soccer players even finish high school. I picked a couple of random pages from chapter 7 and ran them through this neat little tool – it gave a Flesch Reading Ease number of 33.17 (according to the wiki article, this is comparable to an issue of the Harvard Law Review, which “has a general readability score in the low 30s”), and a Gunning Fog index (‘estimates the years of formal education needed to understand the text on a first reading’) of roughly 17 (a score of 12 would be what you’d be aiming for if you wanted a high school grad to easily understand your text – do remember that half of the Danish soccer guys may well be below this level). You can always argue with the algorithms, but I’d remind you that if anything in cases like these they may well tend to underestimate the difficulty involved here – it’s much easier to understand a text with words like ‘strong and specific’ than it is to understand a text with words like ‘the medial pectoral’, yet the two combinations of words score the same in these algorithms (same number of words, same number of letters in each word). And there are a lot of words of the latter kind in this book. I say good luck reading and understanding this book if you’re a Danish high school dropout pro soccer player (I haven’t even talked about the fact that the book is written in a foreign language yet). Note incidentally that roughly one-third (31%, according to the introduction) of all elite soccer injuries are muscle injuries, and that “Hamstring injury is the single most common injury in professional football” (some of the findings of this paper are included in the book) – it’s not like the stuff covered in this book isn’t potentially relevant to these people.

I’ve often seen this sort of stuff before in the introductory chapters of academic publications – academics writing stuff which they delude themselves into thinking that a lot of other people will easily be able to read and understand – and I often have some trouble figuring out how to react to this. I find it sad in a way. I should perhaps point out in connection with this that I at least occasionally think about this type of stuff when blogging; however although I do put in at least some efforts trying to only post stuff ‘other people’ might at least arguably be expected to understand, at least to some extent, and avoid superfluous technicalities, I hardly delude myself into thinking that lots of people will not encounter some problems if they try reading some of the specific posts on this blog. This is not a problem as the blog isn’t really written for the general public; rather it’s mainly written for myself and the few other people out there who find the kind of stuff I write here interesting. I assume that given my limited interaction with ‘normal people’ I occasionally make inferential mistakes regarding comprehensibility qualitatively similar to those of the authors of this book, which is another reason why I have ambiguous feelings about this kind of stuff, but at least I have some awareness of these issues. One might of course argue that the authors assume that only a few players might benefit from the book, but given that some might benefit after all they chose to include that category of potential readers as well – and although I’m far from sure, that may be what’s going on. Maybe the fact that I so often read stuff that’s technically not ‘written for people like me’ makes me more attuned to these kinds of aspects than I perhaps ought to be.

So anyway, with that major digression out of the way, let’s talk a bit more about what this book is about. Naturally it doesn’t deal with all muscle injuries – there are a lot of muscles in the human body (‘approximately 642‘, though numbers vary – this seems like yet another area of biology where there’s a splitter/lumper dynamic at play) and it’d be a very long book if it dealt with every single one of them in detail. Aside from that a lot of textbooks have also already been written about some specific muscle groups, making coverage of those in a book like this somewhat unnecessary – for example there’s quite a literature on what happens when the heart muscle gets damaged and what you can do about it when that happens, so although acute muscle injuries that affect the myocardium may well be some of the most important ones in terms of human morbidity and mortality, they don’t really talk about that kind of stuff in this book. The main focus is on sports injuries – the first two chapters deal with general principles (‘Terminology and Classification of Athletic Muscle Injuries’, ‘Basic Principles of Muscle Healing’), whereas the rest – aside from the last one dealing with ‘Muscle Research: Future Perspective on Muscle Analysis’ – deal with specific muscles or muscle groups. The topics covered are: Hamstring injuries, Acute Adductor Muscle Injury, Quadriceps Muscles, The Calf Muscle Complex, Pectoralis Major Rupture, Acute Biceps Brachii Injuries, and Rectus Abdominis Injury. So what the book does is to provide you with an overview over some common injuries; how they present, diagnosis – it actually turns out that some muscle injuries are much harder to diagnose than you’d think, or at least they’re harder to diagnose than I thought they were – and treatment, etc. It’s probably close to an ideal book to own if you’re an athlete who’s just had a muscle injury; in all likelihood the book will contain some stuff about what’s going on, how worried you should be, how to optimally deal with the injury, etc. Some might presumably also argue that it’s an ideal book to have read if you’re an athlete at risk of getting an injury, and all athletes are, to some extent. Although the book is technical I’d say that if you’re reading this blog I’m pretty sure you’ll be all right – I don’t think a lot of high-school dropout professional soccer players read this blog, although I may be wrong about that…

Here are a few more wiki links (aside from the ones included in the text above) I looked up while reading the book: Anatomical terms of motion, Fascia, Ecchymosis, Myositis ossificans, Compartment syndrome (you do not want this), Tendinitis, Iontophoresis, Metaplasia, Tenosynovitis, Patella, Antalgic gait, Osteitis pubis. This is the kind of stuff that’s covered in the book. I gave the book three stars on goodreads.

I decided to include a few passages from the book below which I thought were interesting and/or worth knowing, as well as a few comments.

…

“Tears of the quadriceps tendon are a rare occurrence […] Patients who have suffered a complete or partial tear of the quadriceps tendon are typically older (>40 years old) and often have conditions that can lead to degeneration in the tendon […] Other patients who are at risk for quadriceps tendon tears are those that use performance-enhancing substances such as anabolic steroids and creatine. These drugs lead to increased muscle strength, and steroids have been reported to weaken tendons, change collagen fibril structure, and decrease tendon elasticity in animal studies. The combination of amplified muscle strength and a potentially weakened tendon increases the likelihood of suffering a tendon rupture.”

I had no idea this was a potential hazard associated with the usage of anabolic steroids. Although I’ve of course never considered using such drugs it’s probably safe to assume that some of the people who actually do use these drugs are also not aware of this risk. A quadriceps tendon tear is incidentally often quite unpleasant: “Incomplete or partial tears of the quadriceps tendon can often be managed nonoperatively. The patient’s knee should be immobilized in full extension for a period of up to approximately 6 weeks depending on the size of the tear.” 6 weeks immobilized – and these are the tears that are categorized as ‘mild’ (of course I’m not saying that if the people using such drugs knew about this risk they’d change their behaviour – some of the commonly known risks involved are much worse as they can actually kill you).

How to treat muscle injuries? The stuff included below is about how to deal with problems with the quadriceps tendons, but similar principles apply to many other muscle injuries (there may be a better coverage of this aspect elsewhere in the book, but this book was one of those books where I was unable to highlight and I am not going to reread the book just in order to find the absolute best quotes to post here):

“Treatment goals for muscle strains are aimed at minimizing the bleeding and hematoma formation following injury to the muscle. There is a scarcity of literature on the specific treatment of muscle injuries, including strains. Because of this, the treatment protocols have not changed drastically in recent years. Acute treatment for strains complies with the PRICE (Protection, Rest, Ice, Compression, and Elevation) protocol for the first 24–72 h following an injury. Ice and compression should be used for approximately 10–20 min at a time in hour-long intervals [10]. Protection and rest are aimed to prevent further damage to the muscle, while ice decreases blood flow, bleeding, and inflammation at the damaged area. The use of ice following acute muscle injuries has been shown to be effective in decreasing pain caused by the injury, but as of yet there is no definitive proof that it leads to faster healing and a quicker return to sports [10,17,25,37]. Compression and elevation both aid in decreasing blood flow and swelling in the injured area. […] Some centers believe that NSAIDs should be contraindicated due to the increased risk of local bleeding and the potential for slower healing of the injury. Therefore, their use is controversial [35]. […] Practitioners should attempt to avoid prescribing anti-inflammatory medications for patients with quadriceps tendon tears because they have been shown to impair tendon healing.”

I included the last part of that quote in order to illustrate that there’s actually quite a lot of stuff most people probably don’t know about these kinds of things, and that this lack of knowledge may easily lead to behavioural strategies post-injury which may adversely affect outcomes. Behavioural strategies which adversely affect injury outcomes may well from an opportunity cost perspective include the failure to adopt injury-minimizing behavioural protocols, and it’s certain there are some of these in the book which most people do not know anything about. In the specific case here it may be an idea to have in mind that it might well be better to use acetaminophen/paracetamol rather than, say, aspirin in an acute muscle injury context. I could easily include other examples as well from the book of ‘things athletes would benefit from knowing but mostly don’t’, here’s another one:

“If possible, a patient who has suffered a quadriceps contusion should immediately have the knee put in 120° of flexion for approximately 10 min. This has been reported to compress the injury to limit hemorrhage and muscle spasm. Research has shown that patients who are put in 120° of flexion immediately following a quadriceps contusion return to normal range of motion more quickly than those who do not and have a lower chance of developing myositis ossificans [2–4,27].”

A few more observations from the book, first a little bit of stuff about what the future may hold:

“The use of treatment modalities based on biologicals is a popular topic for musculoskeletal disorders. Many studies have evaluated platelet- and growth factor-enriched plasma for tendon pathology; results however vary substantially between studies and affected pathology [2,8,28]. […] A number of growth factors released by platelets, such as PDGF, VEGF, IGF-1, TGF beta, and FGF, promote repair in various soft tissue models. With the results of enriched plasma for other musculoskeletal pathologies in mind, it is a promising future treatment option. As with enriched plasma modalities, other upcoming treatment options also lack any evidence for the here-described pathology. One of them is mesenchymal stem cell (MSC) therapy: regeneration of healthy muscle tissue involves infiltration of tissue- and vascular-derived cells into the wound area, releasing a cascade of mediators (GFs, BMPs, cytokines, and neuropeptides). The hypothetical benefit of MSC therapy lies in the molecular approaches by which MSC, along with genetically modified cells and gene therapy, can synthesize and deliver the desired growth factor in a temporarily and spatially orchestrated manner to the site of injury [1,9].
The current lack of knowledge can be regarded as a contraindication because it is unsure whether the used modalities will enhance regeneration of functional musculous tissue or the formation of scar tissue. This is a serious concern and should be studied meticulously before it is ready to be used in daily clinical practice.”

And lastly a few words on how little we actually know at this point (having including the stuff above I felt that I had to include the stuff below as well):

“We are still faced with a dearth of scientific knowledge on muscle injuries. Despite the growing number of publications over the last three decades, our current knowledge on etiology, prognosis, and therapy is based on only 2,000 published injuries, of which the majority is acute hamstring injuries. If we restrict ourselves to level 1 trials, then there are less than 300 injuries examined. The progress our research has led to for the individual athlete is limited: compared to three decades ago the injury and re-injury rate have not been changed. […]

The device “prevention is better than cure” certainly holds for muscle injuries […] Nonetheless, to date the evidence for preventative measures is limited to only one high-level study, in which the Nordic hamstring exercise was shown to be effective in the prevention of hamstring injury in football [17].
To be able to direct preventative measures to those players at risk for a specific muscle injury, risk factors associated with the injuries need to be identified. Unfortunately, studies published to date on risk factors for muscle injuries have methodological limitations, as they use univariate approaches and have too small sample sizes to detect small to moderate associations. Muscle injuries in sports occur from a complex interaction of multiple risk factors. This multifactorial nature should be taken into account when studying risk factors for muscle injuries by using appropriate multivariate statistical approaches [3,13]. In addition, sample sizes should be sufficient to study associations of risk factors with injury risk. As clearly depicted by Bahr and Holme [3], to detect moderate associations up to 200 injured subjects are needed. Taking hamstring injuries in football as an example, with a seasonal injury prevalence of 17 %, a sample size of over 1,000 players is needed to study the risk factors with moderate associations. Risk factor studies in the other less prevalent muscle injuries will of course need even larger numbers of athletes. […] Our main limitation is that as an individual sports physician, we deal with a too limited number of muscle injuries to justify an experience-based approach. For example, in professional football, with 15 muscle injuries per team per season [7], our most experienced sports physicians will have had managed just 450 muscle injuries in his/her 30 years’ career. As a consequence, to gain expertise and to answer the most important and simple questions, we need to collaborate. Faced with our short research history, a worldwide muscle injury registration system should start today rather than tomorrow.”

From a brief google it incidentally seems as if that last part is a topic which has received some attention lately – see e.g. this and this.