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Figure 8 – The Achilles tendon ruptures about 21⁄2 to 3 inches above its insertion into the calcaneus (marked). This is referred to as the “watershed area.” This area of the tendon has a tenuous blood supply, which makes it susceptible to rupture. |
Examination findings. Achilles tendon ruptures occur 21⁄2 to 3 inches above the tendon’s insertion into the calcaneus (Figure 8). If there is no soft tissue swelling, a defect in the tendon may be visible and/or palpable in this area. This defect is associated with discrete tenderness. Although the presence of soft tissue swelling may obscure this defect, discrete tenderness will still be noted in this area of the Achilles tendon—21⁄2 to 3 inches above the tendon’s insertion into the calcaneus.
The Thompson test can be used to evaluate the integrity of the Achilles tendon. With the patient lying prone with knees extended and feet hanging over the end of the examination table, the examiner squeezes the gastrocnemius muscles. The normal response is a slight plantar flexion of both ankles. The test is considered positive for an Achilles tendon rupture when the amount of plantar flexion of the affected foot is diminished or absent compared with the normal foot (Figure 9).
Radiographic findings. No radiographic findings are associated with this injury.
Management. Immobilization and an orthopedic referral are warranted when the diagnosis is either strongly suspected or confirmed by the history and examination. For a successful outcome, definitive treatment, typically surgical repair, should be done within 5 to 10 days of the injury.
3 – Tibialis Posterior Tendon Rupture
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Figure 9 – The Thompson test, used to determine the integrity of the Achilles tendon, is performed with the patient lying prone with his or her knees extended and feet off the table. If the Achilles tendon is intact, the amount of plantar flexion of both feet will be equal when the gastrocnemius muscles are simultaneously squeezed. The test is considered positive when the amount of plantar flexion on the involved side is diminished or absent. |
Mechanism of injury. A rupture of the tibialis posterior tendon is the end result of attritional changes from chronic tendon inflammation. The rupture most commonly occurs with a seemingly benign activity. For unknown reasons, this injury occurs primarily in women 45 years and older.
Symptoms typically experienced. The discomfort the patient feels at the time of the rupture is minimal. In some cases, this discomfort is so minimal that loss of arch support is the patient’s chief complaint.
Extent of disability. The extent of disability is significant. Patients are able to walk or limp on the injured ankle; however, they have an altered gait as a result of the functional loss of the contributions of the tibialis posterior muscle to the sophisticated motions of the ankle with ambulation.
Examination findings. Patients may have discrete tenderness with or without swelling over the area posterior and inferior to the medial malleolus (Figure 10). The tibialis posterior muscle, which is primarily responsible for inversion of the foot, is also an accessory plantar flexor of the foot and is one of the key structures that help maintain the foot arch. When the tibialis posterior tendon ruptures, the patient’s ability to actively invert the plantar flexed foot and hold the foot in inversion against manual resistance is greatly diminished on the affected side. With the patient standing, loss of the longitudinal arch of the involved foot compared with the noninvolved foot is commonly detected.
Radiographic findings. No radiographic findings are associated with this injury.
Management. Immobilization and orthopedic referral are warranted when the diagnosis is either strongly suspected or confirmed by the history and examination. Because of tendon attrition and chronic inflammation, surgical repair of tibialis posterior tendon rupture is usually difficult, and the results of both nonsurgical treatment and surgery are either very poor or poor in most cases. Thus, the ideal management is prevention of recurrence.
Preventive treatment includes rest, anti-inflammatory medication, calf stretching exercises,4 and sometimes immobilization—if all other conservative measures fail to resolve tendon tenderness. If the patient has pes planus, the use of an over-the-counter semi-rigid arch support (orthotic) may be beneficial. Advise patients to refrain from all activities until they have no swelling or discomfort in the area and have achieved adequate flexibility of the calf muscles. Patients should be educated about the attritional changes that occur when the inflammation is not appropriately treated before their return to activities and how these changes compromise the effectiveness of treatment.
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Figure 10 – Patients who have chronic inflammation of the tibialis posterior tendon present with discomfort with or without swelling posterior to the medial malleolus. Management is directed at prevention of rupture of the inflamed tendon. |
Other tibialis posterior tendon injuries. Avulsion fractures of the tendon’s insertion site onto the navicular bone and ruptures of the extreme distal portion of the tendon have both been reported in younger athletes with a previously healthy ankle. Both of these injuries are described as infrequent; however, health care providers should be aware of them.
The mechanism of injury is resisted inversion or forced eversion of the ankle. Patients feel a sharp pain and/or pop in the area of the navicular on the superior midportion of the arch at the time of the injury. The extent of the disability is significant. Patients are forced to hobble or limp dramatically because of the pain.
The examination reveals discrete pain over the area of the navicular and decreased ability to invert the plantar flexed foot and to resist manual eversion of the plantar flexed foot.
Treatment is immobilization and early orthopedic referral for surgical intervention. The surgical outcome is excellent if these injuries are recognized early.
