Emerging Insights On Percutaneous Repair Of The Achilles Tendon Rupture
The Achilles tendon is the largest and strongest tendon in the human body. Increased interest in physical fitness and athletic activity by young, middle-aged, and older patients has led to a higher incidence of rupture.1 Surgical correction is often the treatment of choice because it offers less immobilization time, early weightbearing, better rehab potential, lower risk for re-rupture and faster recovery with return to activity.2 Achilles tendon ruptures can take place at any point during a patient’s lifetime but most commonly happen between the ages of 30 and 50.3 It is five times more likely in men and occurs 75 percent of the time 2 to 6 cm proximal to the insertion into the calcaneus.4 They are usually the result of an indirect injury but clinicians have described other mechanisms. Although rare, direct trauma such as lacerations, crushing injuries or direct blows to the posterior leg can cause disruption of the tendon. Researchers have described intrinsic degeneration from chronic tendonitis or tendinosis in up to 10 percent of cases.5,6 Research has also implicated the use of fluoroquinolone antibiotics and corticosteroids in placing patients at a higher risk for rupture.4 Indirect mechanisms are by far the most common reasons for Achilles tendon ruptures and usually involve a rapid loading moment on an already tensed tendon. A frequent mechanism in the non-athlete is an abrupt and unexpected dorsiflexion force to the ankle combined with a strong contraction of the muscle unit. Examples of this would be stepping off a curb wrong, unexpectedly stepping into a hole or misjudging the dismount off a ladder. A common mechanism in the athlete is pushing off a planted foot while the knee is extended. This often occurs with tennis or racquetball players who lunge for a ball. Another common mechanism is a violent dorsiflexion moment on a plantarflexed ankle. One can see this with jumping from a height or in a gymnast doing a tumbling run.7
Pertinent Anatomical Insights
The Achilles tendon is a conjoined tendon formed from the gastrocnemius and soleus muscles (triceps surae). The tendon rotates 30 to 150 degrees before it inserts onto the posterior aspect of the calcaneus. There is a thin paratenon surrounding the tendon that is susceptible to damage during a rupture.8 The blood is supplied mostly from the posterior tibial artery feeding the gastrocnemius and soleus muscles. The tendon feeds directly from the myotendinous junction, mesosternal vessels, paratenon, and the bone-tendon junction at the insertion into the calcaneus. The “watershed” area is located 2 to 6 cm proximal to the insertion and this is where most ruptures occur. Researchers have shown that the “watershed” area has a diminished blood supply relative to the rest of the tendon that worsens with age.9 The sural nerve courses along the lateral aspect of the Achilles tendon and is anterolateral to the short saphenous vein. It is susceptible to damage during the initial injury and with the surgical repair process. The plantaris arises close to the lateral head of the gastrocnemius muscle. It forms a long, slender tendon that runs along the medial aspect of the Achilles. It is absent 7 percent of the time and is frequently damaged during an Achilles rupture.8 When the plantaris is present, one can use it to help augment the repair.