Conquering Achilles Tendonitis In Athletes
In a survey of professional athletic trainers and team physicians, Achilles tendonitis ranked third behind ankle sprains and plantar fasciitis as the primary presenting complaint within the athletic population.1 Additionally, it accounts for up to 18 percent of all running injuries.2 The condition is highly prevalent among runners, but it is also common in any athlete who endures repetitive high impact microtrauma.3 Regardless of the afflicted population, Achilles tendonitis can severely hamper an athlete’s training and has been the impetus for many athletes to end their careers. Several factors can precipitate the development of Achilles tendonitis, which is known by numerous other terms including tendinosis, peritendinitis, tenosynovitis, peritendinopathy and Achilles tendinopathy. Overuse can be a cause, especially among the “weekend warrior” athletes. When it comes to elite athletes, however, biomechanical abnormalities that cause abnormal or prolonged pronation or excessive supination can be an etiological factor. Rheumatic disorders, although they are much less common, can be an underlying etiology. Sudden increases in training, training intensity, changes in training surfaces, changes in shoegear and muscular imbalance can all play a role.3 Ensure A Thorough Anatomical Understanding In order to provide optimal care, it’s essential to have a thorough knowledge of the associated anatomy of the superficial posterior leg and hindfoot. The gastrocnemius originates as medial and lateral muscle bellies from their respective femoral condyles and courses down the upper half of the leg, transitioning to a wide aponeurosis and ultimately uniting with the soleus to form the tendo Achilles. The soleus takes its origins from the posterior tibia, fibula and interosseous membrane, courses down the leg and ultimately shares its final attachment with the gastrocnemius through the tendo Achilles. The tendo Achilles has a broad insertion on the middle one-third of the posterior calcaneus and sends fibers around the undersurface of the calcaneus to unite with the plantar fascia. The tendo Achilles inserts medially to the subtalar joint axis. Between the superior surface of the calcaneus and the Achilles is the retrocalcaneal bursa, which provides protection and cushioning of the tendon from the adjacent bony surface. Unlike the invariably present retrocalcaneal bursa, the pre-Achilles bursa, which lies between the tendon and the skin, has a less frequent presence. The tendo Achilles is not surrounded by a synovial sheath to constantly bathe the tendon in nourishing synovial fluid, but rather a paratenon. This affects the healing process of the tendon. The paratenon consists of the intimately associated epitenon and the overlying peritenon. The gastroc/soleal complex receives its proximal blood supply from muscular arterial branches. Distally, the common tendon receives its vascularity from the vessels in the peri- and endotenon, musculotendinous junction, osseous insertion and the mesotenon. Lagergran and Lindholm have shown that the tendo Achilles, 2 cm to 6 cm proximal to its calcaneal insertion, is relatively avascular. They have called this the “watershed area.”4 Just prior to the insertion of the tendon onto the Achilles, the fibers undergo a 90-degree turn in which the lateral fibers become posteriorly oriented.5 This provides significant torsional stress on the tendon/bone interface and often is the site of pathology. Unfortunately, as mentioned earlier, potential healing in this area is altered by the relative avascularity and a lack of a synovial sheath. Understanding the mechanics of the gastroc/soleal complex is equally important. The gastrocnemius spans three joints: the knee, ankle and subtalar joint. The soleus crosses the ankle and subtalar joints. Collectively, they function as ankle joint plantarflexors and supinators of the subtalar joint, while the gastroc also flexes the thigh relative to the leg. The gastroc/soleal complex is active from the contact phase of gait to early propulsion. The soleus is active before the gastrocnemius and stabilizes the lateral foot onto the ground during stance and helps to decelerate the STJ during pronation. The soleus also decelerates the forward momentum of the tibia at midstance and propulsion. The gastroc simultaneously plantarflexes the ankle, flexes the knee and supinates the STJ at propulsion.