Foot and Ankle cases 1

A 40-year-old male, recreational basketball player presents 1 week after feeling like he was kicked in the back of the leg while coming down from a rebound. He was initially seen at an outside facility where he was diagnosed with an ankle sprain. One week prior to the injury he reports that he was given antibiotics for a sore throat.

Which of the following antibiotics would increase the chance of an Achilles tendon rupture?

1. Keflex

2. Clindamycin

3. Ciprofloxacin

4. Azithromycin

 

Discussion

The correct answer is (C). Fluoroquinolones have been implicated in tendon rupture secondary to two theories. One theory is a decrease in blood flow, which causes an increase rate of rupture. The second theory is that there is a decrease in transcription of decorin, which modifies the biomechanics of the tendon itself, resulting in increased fragility. The mechanism of action of fluoroquinolones is inhibition of DNA topoisomerase II, which results in an inability for the cell to replicate. Keflex, clindamycin, and azithromycin have not been implicated in tendon pathology. The mechanism of action of keflex is disruption of cell wall synthesis. The mechanism of action of clindamycin is inhibition of protein synthesis through binding to the 50S ribosome. The mechanism of action of azithromycin is binding to the 50S ribosome and inhibiting protein synthesis. Other risk factors for Achilles rupture

include steroid use, steroid injections into the tendon, inflammatory arthropathy, and prodromal Achilles tendinosis.

Fortunately you learn that the patient had been started on azithromycin. On examination it is noted that he has no plantar flexion with calf squeeze, a palpable gap, and tenderness around his Achilles.

Based upon ischemic regions of the tendon, what is the most likely location of rupture?

1. Musculotendinous junction

2. 12 cm proximal to the insertion

3. 5 cm proximal to the insertion

4. Avulsion off the calcaneus

 

Discussion

The correct answer is (C). The blood supply for the Achilles tendon is predominantly from the muscular region and from the bony insertion, resulting in a relative watershed area located at the midportion of the tendon approximately 2 to 6 cm proximal to the insertion of the tendon. The average location of rupture is 4.7 cm proximal to the insertion site.

The diagnosis of Achilles tendon rupture is made with clinical examination including a palpable gap, lack of dorsiflexion with calf squeeze, and increased passive dorsiflexion of the ankle. Additional tests include placement of a needle percutaneously into the proximal Achilles and dorsiflexing the ankle looking for movement of the needle. Another test involves placing a sphygmomanometer around the calf with the cuff inflated to 100 mm Hg while the foot is plantar flexed. Dorsiflexion of the foot should result in an increase in pressure to 140 mm Hg.

Radiographic findings of an Achilles rupture may include disruption of Kager’s triangle on the lateral x-ray. This is the fat-filled region located superior to the calcaneus, anterior to the Achilles, and posterior to the flexor hallucis longus (Fig. 5–1). Ultrasound and MRI will demonstrate a gap in the Achilles at the location of rupture.

 

 

Figure 5–1 The normal outline of Kager’s triangle on the lateral x-ray is the radiolucent region bordered by the Achilles posteriorly, flexor hallucis longus muscle belly anteriorly, and superior border of the calcaneus inferiorly.

 

The patient is interested in treatment options for his rupture. Based upon the latest data available, which of the following is unable to be recommended as a treatment option?

1. Cast in plantar flexion for 10 weeks followed by mobilization in a cam boot

2. Splint placement followed by early rehabilitation with physical therapy

3. Acute repair through a percutaneous approach

4. Acute repair through an open approach followed by weight bearing in a boot at 4 weeks

Discussion

The correct answer is (A). The AAOS clinical practice guidelines give a moderate recommendation to employ a protective device that allows mobilization by 2 to 4 weeks postoperatively. Classically there has been reported an increased re-rupture rate with nonoperative management of acute Achilles tendon ruptures when compared to surgical treatment. Re-rupture rates after nonoperative treatment of the Achilles have been quoted at 12% or higher, with re-rupture rates of surgical treatment quoted at 4%. The higher rates of re-rupture have occurred in groups with

prolonged immobilization of their nonoperatively treated rupture.

Recently there has been a push for earlier motion following either operative or nonoperative treatment. Level 1 evidence from Willits et al. (J Bone Joint Surgery Am, 2010) demonstrated similar outcomes of surgical and nonsurgical treatment utilizing an early motion protocol. There was a statistically significant difference in strength favoring operative treatment, however there were more soft tissue complications in the surgical treatment group. Percutaneous repair of Achilles tendon rupture is an option and has been demonstrated to yield similar benefits as standard open repair based on level 2 evidence with potentially fewer soft tissue complications.

The patient elects for surgical treatment. He undergoes repair via a standard open repair. What is the most common complication associated with this surgery?

1. Superficial wound complications

2. Saphenous nerve injury

3. Sural nerve transection

4. Deep wound infection

 

Discussion

The correct answer is (A). This has been reported as high as 17% (Bhattacharyya, 2009) with open operative treatment, although the true incidence is likely significantly lower. The sural nerve lies superficial to the tendinous portion of the Achilles at approximately 10 cm proximal to the insertion of the Achilles tendon and may be encountered during the approach, especially with more proximal ruptures. The saphenous, deep peroneal, and superficial peroneal nerves should not be at risk during an Achilles repair. Although deep wound infection is a major complication associated with Achilles tendon repair, it is most commonly reported at approximately 1%.

 

Objectives: Did you learn...?

 

Identify association between fluoroquinolone antibiotics and Achilles tendon rupture?

 

 

Pinpoint watershed region of the Achilles tendon? Treat for acute Achilles tendon ruptures?