Achilles Tendon Rupture

Background
Complete ruptures tend to occur in middle-aged patients and those without preexisting complaints. Partial ruptures occur in well-trained athletes and involve the lateral aspect of the tendon. Acute ruptures commonly result from acute eccentric overload on a dorsiflexed ankle that has chronic tendinosis. Patients should be questioned about previous steroid injection and fluoroquinolones (possible association with tendon weakening and rupture).

Clinical Signs and Symptoms
Sharp pain and a pop heard at the time of complete rupture are commonly reported. Patients often describe a sensation of being kicked in the Achilles tendon. Most have an immediate inability to bear weight or return to activity. A palpable defect may be present in the tendon initially.

Partial rupture is associated with an acutely tender, localized swelling that occasionally involves an area of nodularity.
The Thompson test (see Fig. 5–39) is positive with complete Achilles tendon rupture. A positive test occurs when squeezing the calf fails to plantar flex the foot because of a lack of continuity of the tendon (rupture).

Thompson Test
The patient is placed prone, with both feet extended off the end of the table. Both calf muscles are squeezed by the examiner. If the tendon is intact, the foot will plantar flex when the calf is squeezed. If the tendon is ruptured, normal plantar flexion will not occur (a positive Thompson test).

In some patients, an accurate diagnosis of a complete rupture is difficult through physical examination alone. The tendon defect can be disguised by a large hematoma. A false-negative Thompson test can occur because of plantar flexion of the ankle caused by extrinsic foot flexors when the accessory ankle flexors are squeezed together with the contents at the superficial posterior leg compartment. It is important to critically compare the test with results in the normal side.

Partial ruptures are also difficult to accurately diagnose, and MRI should be used to confirm the diagnosis.

Treatment of Acute Rupture of the Achilles Tendon
Both conservative and operative treatments are commonly used to restore length and tension to the tendon to optimize strength and function. Both methods are reasonable, and treatment should be individualized based on operative candidacy. High-level and competitive athletes usually undergo primary repair. Operative repair is associated with lower re-rupture rates, quicker return to full activity, and a theoretically higher level of function. However, the difference in outcomes between conservative and operative treatment is variable. The main surgical risk is wound breakdown. Generally, surgery should be avoided in patients with poor wound healing potential (diabetics); smoking is a relative contraindication.

Regardless of definitive treatment, initial treatment is a short-leg splint in a comfortable position of plantar flexion, ice, elevation, and crutch ambulation.

Nonoperative treatment of complete Achilles tendon ruptures in a 20-degree plantar flexed cast is usually reserved for chronically ill patients, poor operative candidates, elderly patients, and low-demand patients. The re-rupture rate is much higher in patients treated nonoperatively (with a plantar flexed cast for 8 weeks of non-weight-bearing) than in those treated operatively. A review of multiple studies found an average re-rupture rate of 17.5% in nonoperative patients compared with 1.2% in operatively treated patients. However, major and minor complications were more frequent with operative treatment.

Nonoperative Treatment of Acute Achilles
Tendon Rupture
Nonoperative treatment for poor operative candidates requires immobilization to allow hematoma consolidation. Ultrasound is used to confirm that tendon end apposition occurs with 20 degrees or less of plantar flexion. Conservative treatment is best for small partial ruptures. Surgical repair is indicated if a diastasis or gap remains with the leg placed in 20 degrees of plantar flexion.

A 20-degree non–weight-bearing plantar flexed short-leg cast (preference) or a removable boot (not to be removed by the patient) with an elevated heel is used for 8 weeks. The patient remains non–weight-bearing in the cast for 8 weeks.

At 6 to 8 weeks, plantar flexion of the cast is slowly decreased (most easily done in a commercial cam boot with adjustable ankle angle setting). An initial heel lift of 2 to 2.5 cm should be worn for 1 month when progressive weight-bearing is begun. Gentle non–weight-bearing active ROM exercises and gentle passive stretching with rubber tubing are begun. At 10 to 12 weeks, the heel lift is decreased to 1 cm and, over the next month, is progressively decreased so that the patient is walking without a heel lift by 3 months.

Progressive resistance exercises for the calf muscles should be started between 8 and 10 weeks. Running may be resumed after 4 to 6 months if strength is 70% of the uninvolved leg. Maximal plantar flexion power may not return for 12 months or more.

Operative Treatment for Complete Achilles
Tendon Rupture
Operative treatment is generally preferred for young, athletic, and active patients. The incision and approach are the same as for paratenonitis and tendi-nosis. A medial approach is used to expose the tendon ends, and a modified Bunnell technique is used to repair the rupture.