Although rare, herniation that the tibialis anterior muscle may be an ext common than formerly thought. Andrew Hamilton explores the causes, diagnosis, and treatment choices for this injury.
You are watching: Hernia of a muscle through the fascia surrounding it
Norwegian skier Petter Northug 2018. NTB Scanpix/Geir Olsen/
Muscle herniation, also known together a myofascial defect, is the protrusion the a muscle v the bordering fascia. The most typical location that muscle herniation is in the leg. Because this injury is tricky to diagnose and rarely reported, over there is little data in the literature upon which to draw(1-3). A rise of reports the lower-extremity muscle hernias in physically energetic military recruits showed up in military medical journals during the 1940s(4-7). Therefore, the majority of at an early stage research on foot hernias (and much of our present knowledge) stems native the efforts of armed forces surgeons.
Tibialis anterior hernia incidence
The true incidence of foot hernias is no known. Numerous are asymptomatic and, thus, remain undiagnosed(8). The most commonly diagnosed muscle herniation is of the tibialis anterior (TA)(9-12). Herniation at this location is likely because the fascia of the tibialis anterior is weak and vulnerable come trauma(13). Though much less common, other lower-limb muscles have the right to herniate, including the peroneus brevis(14), extensor digitorum longus(15), gastrocnemius,(16) and flexor digitorum longus (see figure 1)(6).
Figure 1: Cross-section of lower limb showing fascial compartments
TA = tibialis anterior; TP = tibialis posterior; EHL = extensor hallucis longus; EDL = extensor digitorum longus; FDL = flexor digitorum longus; FHL = flexus hallucis longus; PB = peroneus brevis; PL = peroneus longus
Etiology that tibialis anterior hernia
Tibialis anterior hernias are typically associated with trauma, direct or indirect, and also congenital weaknesses of the fascial tissue neighboring the TA (see number 2). Traumatic instances include(17):Penetrating traumaClosed fracture that reasons a fascial tear (direct trauma)Force applied to the contract muscle leading to acute fascial rupture (indirect trauma)
Congenital weakness might involve the fascial tissue as a totality or just a localized website where blood vessels and also nerves pass with the fascia(18).
Athletes who endure a TA hernia without a history of trauma are likely to have some level of congenital weak in the TA fascial tissue. Studies imply that fascial defects are an ext common than appreciated. For example, one study discovered that fascial defects were present in 15% to 50% of patient undergoing surgery for chronic exertional compartment syndrome (CECS) – even though pre-operation examinations to be normal(19). Due to the fact that increased intracompartmental press potentiates herniation, soldiers, athletes, mountain climbers, skiers, etc, space at much greater risk of emerging a TA hernia than the population at large(20,21).
Figure 2: rundown of TA hernia etiology
Signs and symptoms
A patient v a TA hernia generally presents through a range of symptoms, including:A localized ede or nodule(s) over a part of the anterior shin, i m sorry is soft and may it is in mildly tender.A dull pain localized come the site of the ede that increases upon weight-bearing and also activity.Cramping, discomfort, weakness, or neuropathy.Possible numbness in the lateral section of the lower leg and also foot the the influenced side.A to decrease in swelling once in the supine position. This reduction may likewise occur with muscle inactivation.An increase in localized pain and swelling size when the lower leg is placed in the ‘fencer’s lunge’ position (see number 3).
The differential diagnoses of this symptoms should encompass the adhering to which present similarly(18):LipomaHematomaFibromaEpidermoid cystTumorAngiomaArteriovenous aneurysmRuptured muscleCentral neuropathy
A exactly diagnosis that TA herniation permits the athlete to begin rehab immediately, and also prevents unnecessary diagnostic procedures and also associated psychological stress.
Although the data is limited, it is typical for patients to screen normal strength and patellar/Achilles reflexes. In TA situations of traumatic origin, patients might report having actually experienced particularly intense ache at the moment of injury, and there may be a authorize of the original trauma. In congenital cases, no indicators of trauma will certainly be evident. If the observed swelling/nodule is palpable and also reducible v muscle inactivation or the adoption of a supine position, clinicians can feel relatively confident the a hernia is present. Therefore, without clinical and orthopedic red flags, there’s frequently no require for more diagnostic procedures, particularly following trauma(22). Magnetic resonance imaging (MRI) and also ultrasound imaging can help confirm the diagnosis.
Figure 3: Fencer’s lunge position
Although MRI allows far better visualization that the muscle-fascia demarcation, and also determination the herniated muscle volume, the gold standard for imaging, is ultrasonography because of its relative ease and also low cost(23). If available, 3-dimensional dynamic ultrasound scanning with surface rendering is superior to timeless two-dimensional scans because it provides much better visualization of the fascial planes and muscular protrusion(24). However, magnetic resonance imaging comes into its own have to conservative therapies for a TA hernia fail and also surgery is needed, or when ultrasound imaging is inconclusive. In particular, that assists in surgical planning by assessing surrounding neuro and musculoskeletal tissues, quantifying fascial splitting, and determining the level of muscle herniation.
There’s no clear agreement on conservative therapy protocols because that TA herniation. In the situation of one asymptomatic TA hernia (which the clinician is less likely to encounter), patience reassurance and education room all the is required(25). However, once painful symptoms space present, control conservatively through rest, load modification, and compression stockings(26).
Some research suggests that a more proactive approach, combine isometric, eccentric, and plyometric exercises, yields valuable results(27). In this instance study, the patient – a 28-year-old male soccer player presenting with a trauma-induced TA herniation injury come his appropriate anterior shin embarked on the complying with protocol:Stage 1 (approx. Two weeks) – rest (i.e., non-weight bearing), the use of compression stockings, and isometric convulsion exercises for the tibialis anterior muscle (in the supine place to minimize any potential intracompartmental push from weight-bearing). The usage of isometric contraction help activate high-threshold motor units associated in exercise-induced analgesia(28).Stage 2 (approx. Two weeks) – exercise loading evolved to concentric contraction of TA muscle in supine and also in weight-bearing positions.Stage 3 – Eccentric exercises to be employed because that the TA muscle come generate force over a greater muscle length and stimulate maximal organization adaptation to elastic force. This setting of exercise appears effective because the elastic energy stored throughout the lengthening phase of the eccentric contraction can be used throughout the shortening phase of muscular convulsion to amplify force and also power production throughout exercise(29).Stage 4 – In the last phase of rehab, sports-specific plyometrics practice were presented to create sports-specific multidirectional force and also stability with neural adaptation.
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When TA herniation occurs together a result of trauma, a graded, stepwise, conservative treatment strategy may produce good results within eight weeks. However, wherein the reason is congenital, or over there is a history of chronic TA herniation, operation repair may be needed. Traditionally, the most typically used surgical an approach is the direct closure of the fascia defect through tightening the area. However, a retrospective analysis of this procedure concluded that this frequently results in a high re-herniation rate and also increases intracompartmental pressure, which predisposes the patient to compartment syndrome later(30). A more successful and also current surgical method is a longitudinal decompressive fasciotomy, which outcomes in less intracompartmental pressure and lower price of re-herniation. An alternate surgical alternative is to repair the fascia using fabricated patches.