Continuing Education Activity

Achilles tendon rupture is the most common tendon rupture in the lower extremity. The injury most commonly occurs in adults in their third to fifth decade of life. Acute ruptures often present with sudden onset of pain associated with a "snapping" or audible "pop" heard at the site of injury. Patients may describe a sensation similar to being kicked in the lower leg. Achilles tendon rupture causes significant pain and disability. This activity reviews the etiology, presentation, evaluation, and management of Achilles tendon rupture and examines the role of the interprofessional team in managing it.

Objectives:

• Describe risk factors associated with Achilles tendon rupture.
• Explain how the Thompson test is performed and what a positive test suggests.
• Describe the factors to consider when deciding whether to treat an Achilles tendon rupture with operative versus nonoperative management.
• Describe how an optimally functioning interprofessional team would coordinate care to enhance outcomes for patients with Achilles tendon rupture.

Introduction

Achilles tendon rupture is the most common tendon rupture in the lower extremity. The injury most commonly occurs in adults in their third to fifth decade of life.[1]  Acute ruptures often present with sudden onset of pain associated with a "snapping" or audible "pop" heard at the injury site. Patients can describe the sensation of being kicked in the lower leg. The injury causes significant pain and disability.

Achilles tendon injuries typically occur in individuals who are only active intermittently (i.e., the "weekend warrior" athletes). The injury is reportedly misdiagnosed as an ankle sprain in 20% to 25% of patients. Moreover, patients in their third to the fifth decade of life are most commonly affected, as 10% report a history of prodromal symptoms, and known risk factors include prior intratendinous degeneration (ie, tendinosis), fluoroquinolone use, steroid injections, and inflammatory arthritides.[2][3][4][5]

Etiology

Causes of Achilles tendon rupture include sudden forced plantar flexion of the foot, direct trauma, and long-standing tendinopathy or intratendinous degenerative conditions. Sports often associated with Achilles tendon rupture include diving, tennis, basketball, and track. Risk factors for a rupture of the Achilles tendon include poor conditioning before exercise, prolonged use of corticosteroids, overexertion, and the use of quinolone antibiotics. The Achilles tendon rupture usually tends to occur about two to four cm above the calcaneal insertion of the tendon. In right-handed individuals, the left Achilles tendon is most likely to rupture and vice versa.[6][7][8]

The exact cause of Achilles tendon injury appears to be multifactorial. The injury is most common in cyclists, runners, volleyball players, and gymnasts. When the ankle is subject to extreme pronation, it places enormous stress on the tendon, leading to injury. In cyclists, the combination of low saddle height and extreme dorsiflexion during pedaling may also be a factor in an overuse injury.

Systemic Factors

Systemic diseases that may be associated with Achilles tendon injuries include the following:

• Chronic renal failure
• Collagen deficiency
• Diabetes mellitus
• Gout
• Infections
• Lupus
• Parathyroid disorders
• Rheumatoid arthritis
• Thyroid disorders 

Foot problems that increase the risk of Achilles tendon injuries include the following:

• Cavus foot
• Insufficient gastroc-soleus flexibility and strength
• limited ability to perform ankle dorsiflexion
• Tibia vara
• Varus alignment with functional hyperpronation

Achilles tendon rupture is often more common in people with blood group O. Further, anyone with a family history of tendon rupture is also at a high risk of developing Achilles tendon rupture at some point in their life.

Epidemiology

The incidence of Achilles tendon ruptures vary in the literature, with recent studies reporting a rate of 18 patients per 100,000 patient population annually. Regarding athletic individuals, the incidence rate of Achilles tendon injuries ranges from 6% to 18%, and football players are the least likely to develop this problem compared to gymnasts and tennis players. About a million athletes are believed to have Achilles tendon injuries each year.

The true incidence of Achilles tendinosis is unknown, although reported incidence rates are 7% to 18% in runners, 9% in dancers, 5% in gymnasts, 2% in tennis players, and less than 1% in American football players. Achilles disorders affect approximately 1 million athletes per year.[9]

The incidence of Achilles tendon injuries is increasing in the USA because of more participation of people in sporting activities. The exact incidence of Achilles tendon injuries is unknown outside the USA, but studies from Denmark and Scotland reveal 6 to 37 cases per 100,000 persons.

Achilles tendon injuries appear more commonly in males, probably related to greater participation in sports activities. Most injuries are seen between the third and fifth decade of life. Many of these individuals are only active intermittently and rarely warm up.

Pathophysiology

Achilles tendonitis is often not associated with primary prostaglandin-mediated inflammation. It appears there is a neurogenic inflammation with the presence of calcitonin gene-related peptide and substance P present. Histopathological studies reveal thickening and fibrin adhesions of the tendon with the occasional disarray of the fibers.

Neurovascularization is frequently seen in the degenerating tendon, which is also associated with pain. Tendon rupture is usually the terminal event during the degeneration process. After rupture, type 111 collagen appears to be the major collagen manufactured, suggesting an incomplete repair process. Animal studies show that tendon rupture is most likely if there is more than 8% stretching of their original length.

The proximal segment of the tendon receives its blood from the muscle bellies connected to the tendon. Blood supply to the distal segment of the tendon is via the tendon-bone interface.

History and Physical

Patients often present with acute, sharp pain in the Achilles tendon region. On physical exam, patients with Achilles tendon rupture cannot stand on their toes or have very weak plantar flexion of the ankle. Palpation may reveal a tendon discontinuity or signs of bruising around the posterior ankle.

The examiner performs the Thompson test to assess for Achilles tendon continuity in the setting of suspected rupture. The examiner places the patient in the prone position with the ipsilateral knee flexed to about 90 degrees. The foot/ankle is in the resting position. Upon squeezing the calf, the examiner notes the presence and degree of plantarflexion at the foot/ankle. This should be compared to the contralateral side. A positive (abnormal) test is strongly associated with Achilles rupture.

Evaluation

In the setting of trauma to the lower leg, radiographs are obtained to rule out the presence of a fracture. The diagnosis can be confirmed with ultrasound imaging or MRI based on clinical suspicion following the physical examination. [10]

Treatment / Management

Operative Versus Nonoperative Management

The initial management of Achilles tendon rupture is rest, elevation, pain control, and functional bracing. There is still debate surrounding the potential benefits versus risks of surgical intervention. Studies have demonstrated good functional results and patient satisfaction with both operative and nonoperative modalities. 

Healing rates with serial casting/functional bracing are no different compared to the surgical anastomosis of the tendon, but return to work may be slightly prolonged in patients treated medically. All patients require physical and orthotic therapy to help strengthen the muscles and improve the range of motion of the ankle.[11][4][12]

Rehabilitation is critical to regaining maximal ankle function. While the debate remains regarding the optimal treatment modality, the consensus includes the following:

• Patients with significant medical comorbidities or relatively sedentary lifestyles are often recommended for nonoperative management.
  • Chronicity of the injury and soft tissue/skin integrity is also considered.
• The patient/surgeon discussion should include a detailed discussion concerning the current literature reporting satisfactory outcomes with both treatment plans and the following topics:
  • Possibility of quicker return to work with operative intervention
  • Equivalent plantar flexion strength at long-term followup
  • Possibility of an increased risk of re-rupture and re-injury with nonoperative management (compared to operative management)
  • Lower complication rates for nonoperative treatment compared to operative management

Several techniques for Achilles tendon repair exist, but all involve the reapproximation of torn ends. Sometimes the repair is reinforced by the plantaris tendon or the gastroc-soleus aponeurosis.

Overall, the healing rates between casting and surgical repair are similar. The debate about an early return to activity after surgery is now being questioned. If a cast is used, it should remain for at least 6 to 12 weeks. Benefits of a nonsurgical approach include no hospital admission costs, no wound complications, and no risk of anesthesia. The most significant disadvantage is the risk of re-rupture, which is as high as 40%.

Differential Diagnosis

• Achilles bursitis 
• Ankle fracture
• Ankle impingement syndrome
• Ankle osteoarthritis
• Ankle sprain
• Calf injuries
• Calcaneofibular ligament injury
• Calcaneus fractures
• Deep venous thrombosis (DVT)
• Exertional compartment syndrome
• Fascial tears
• Gastrocnemius or soleus muscle strain or rupture
• Haglund deformity
• Plantaris tendon tear
• Psoriatic arthritis
• Reiter syndrome
• Retrocalcaneal bursitis
• Ruptured Baker cyst
• Syndesmosis
• Talofibular ligament injury

Prognosis

For most patients with Achilles tendon rupture, the prognosis is excellent. But in some non-athletes, there may be some residual deficits like a reduced range of motion. Most athletes can resume their previous sporting activity without any limitations. However, non-surgical treatment has a re-rupture rate of nearly 40% compared to only 0.5% for those treated surgically.

Complications

Re-rupture

• While newer level 1 evidence has reported no difference in re-rupture rates, prior studies have suggested a 10% to 40% re-rupture rate with nonoperative management (compared to a 1% to 2% rate of re-rupture after surgery)
  • Lantto et al recently demonstrated the following in a randomized controlled trial of 60 patients from 2009 to 2013 at 18-month follow-up:
    • Similar Achilles tendon performance scores
    • Slightly increased calf muscle strength differences favoring the operative cohort (10% to 18% strength difference) at 18-month follow-up
    • Slightly better health-related quality of life scores in the domains of physical functioning and bodily pain favored the operative cohort[13]

Wound Healing Complications

• Overall, a 5-10% risk following surgery
• Risk factors for postoperative wound complications include the following:
  • Smoking (most common and most significant risk factor)
  • Female sex
  • Steroid use
  • Open technique (vs percutaneous procedures)

Sural Nerve Injury

• Increased rate of injury associated with the percutaneous procedure (compared to open technique)

Postoperative and Rehabilitation Care

No matter which method is used to treat the tendon rupture, participating in an exercise program is vital. One may swim, cycle, jog, or walk to increase muscle strength and range of motion.

Rehabilitation 

Rehabilitation will vary based on surgical versus non-surgical approach and referring physician’s protocol, highlighting the importance of the therapist working closely with referring physician to optimize care. This is particularly important for brace use and weight-bearing status as these areas are those in which therapy management tends to vary the most with this condition. Depending on operative vs. non-operative, immobilization may range from approximately 3 to 4 weeks in operative and 3 to 9 weeks conservative with orthotic use following both approaches depending on referring orthopedic protocol. Varying degrees of plantarflexion to neutral positioning are utilized during this time, with specifics on the optimal positioning still widely debated.[14][15][16] Emphasizing the need to avoid hyper dorsiflexion during this time has been noted as an important component in avoiding elongation of the Achilles tendon and long-term functional deficits.[14]

If conservative methods are used, therapy begins during the immobilization phase of cast wear for weight-bearing mobilization training and exercise to promote the maintenance of strength in the remainder of the affected limb. More recent studies have shown the benefits of initiating functional casts coupled with early weight bearing in conservative treatment, including a faster return to activity and improved ankle dorsiflexion (traditionally operative treatment corresponded with earlier weight-bearing and exercise initiation), but this continues to vary and will be determined by the referring physician.[14][15][16] 

For surgical patients, rehabilitation exercises typically begin 2 to 4 weeks postop.[17] Post-immobilization therapy consists of exercise progression, including ankle range of motion exercises, resistive and progressive strengthening exercises, isometric exercises, cardiovascular exercises, and balance exercises as appropriate.[18] 

Exercise focus is typically low impact for the first six months, with high-impact exercises incorporated after six months, emphasizing a return to sport as appropriate. Data has shown a need for a heavy focus on calf strengthening within the first year of injury as a reduction in strength gain potential has been demonstrated beyond the one-year post-injury date.[14]

Deterrence and Patient Education

While active patients and recreational athletes often return to baseline activity levels and work following both nonoperative and operative management of these injuries. High-level professional athletes most often report inferior results and return to play regardless of the chosen management plan.

A 2017 study from the American Journal of Sports Medicine reported professional athletes' follow-up performance (NBA, NFL, MLB, and NHL) at 1- and 2-year follow-ups after surgery performed between 1989 and 2013: 

• >30% failure to return to play
• Athletes returning noted (at 1-year follow-up) the following:
  • Fewer games played, overall
  • Less playing time, overall
  • Suboptimal performance level, overall
• Athletes able to return to play by 2-year follow-up show no statistically significant difference in performance level[19]

Thus, athletes demonstrating the ability to return to play by 1-year should expect to achieve continuous improvement to baseline performance by the ensuing season.

Pearls and Other Issues

To prevent Achilles tendon rupture, adequate warming and stretching before physical activity is recommended.

Enhancing Healthcare Team Outcomes

Even though there are several treatments for Achilles tendon rupture, there is no consensus on which to undertake. There is a wide variation in the management of Achilles tendon injury between orthopedic surgeons and sports physicians. Further, there is no uniformity in postoperative rehabilitation. Experts recommend that an interprofessional approach may help achieve better outcomes.[10][20] [Level 5]

The team should include a trauma surgeon, an orthopedic surgeon, a rehabilitation specialist, and a sports physician. The pharmacist must ensure the patient is not on any medications that can affect healing. The nurse should educate the patient on the importance of stretching before any exercise and participating in a regular exercise program after repair.

Outcomes

Conservative treatment is usually preferred for non-athletes, but the risk of re-rupture is high. While surgery offers a lower risk of re-rupture, it is also associated with post-surgical complications that may delay recovery. Overall, the outcomes for Achilles tendon rupture are good to excellent after treatment.[21][22][23] [Level 5]