Tendon Injuries in the lower limb Diagnosis and Classification

Fig. 39.1

Hamstring injury

39.2.1.2 Tendon Injuries Around the Knee

The main patellar pathology is proximal patellar tendinopathy, also known as jumper’s knee. The patellar tendon is more vulnerable to overuse injuries than quadriceps tendon, particularly in adolescents and young adults [19, 20]. Patellar tendinopathy is a common cause of anterior knee pain, is involved with the overuse injury in sports, and is common among athletes in sports with prolonged repetitive stress of the knee extensor apparatus such as jumping (volleyball, basketball), kicking (football, american football), quick stops and starts (tennis, squash), and running [3]. Clinical symptoms may include pain, perceived swelling or fullness, and a sensation of “weakness” or “giving way” [21].

Hägglund et al. [22] published that patellar tendinopathy is a fairly common condition in elite football, and the recurrence rate is high (12–27%). High total amount of exposure was identified as a risk factor for patellar tendinopathy.

The extensor mechanism ruptures are rare injuries, which often occur through a degenerative tendon and produce painful and swollen knee. The patient has difficulty walking and cannot straighten their leg against gravity or resistance due the loss of extensor function. There may be a palpable defect in the suprapatellar or infrapatellar regions and an abnormal position of the patella. Hemarthrosis may or may not be present [23].

These injuries are produced by an eccentric contraction of the quadriceps muscle applied to the flexed knee. In young athletes, the typical mechanism is abrupt deceleration while running. In the elderly population, the most frequent mechanism is a sudden loss of balance that results in a fall on the fixed and flexed knee [20, 23].

Patellar tendon rupture can be the end stage of “Jumper’s knee” due to the cumulative effect of repetitive trauma and microtearing of the tendinous fibers [21].

Quadriceps tendon tears are most common than patellar tendon ruptures and occur most often at the tendo-osseous junction. Usually the patient is around 40–60-year-old man, while the majority of patellar tears are seen at ages between 30 and 50 years. When a sudden flexion occurs in a normal bone, the tendons are susceptible to rupture, but if it is a osteoporotic bone, a patellar fracture might occur. Therefore, patellar and quadriceps tears are rare in woman, but patellar fractures are seen more commonly in them by which hormonal matters have more incidence of osteoporosis [9, 12, 24].

39.2.1.3 Tendon Injuries Around the Ankle

Achilles tendinopathy occurs both in sportspeople and sedentary people. Top level runners have an incidence of 7–9%, and sedentary lifestyle people have 30%. Pain, diffuse or localized swelling, and impaired performance of the Achilles tendon is seen in this clinical condition. Tendinopathy of the midportion of the tendon accounts for 55–65% of all injuries. In the beginning, pain occurs a short while after the end of the exercise. As the pathologic process progresses, pain may occur during the exercise and interferes with activities of daily living. Maffulli et al. [14] name that clinical examination is the best diagnostic tool. Location of pain from 2 to 6 cm above the insertion into the calcaneum and pain on palpation are reliable and accurate tests for diagnosis.

In an acute rupture of the Achilles tendon, the patients report that they thought that they had been struck by an object or kicked in the tendon area. An audible snap usually is reported too. These injuries are common in sports practice, and the patients may present pain, palpable gap, and Thompson signal besides being unable to bear weight and notice weakness.

Although they are common injuries and usually easy to diagnose, there are reports that 20% of cases are not diagnosed by the first examining physician. This indicates that a high index of suspicion is necessary because a neglected rupture will result in greater difficulty in treatment and rehabilitation [1, 14].

Ress et al. [13] cite that gender is a key genetic expression, and women develop less tendinopathy than men, but after the onset of menopause, they are also prone to Achilles tendon ruptures. Estrogen may protect tendons.

The tibialis posterior is the most powerful inverter of the foot and an important dynamic stabilizer of the foot arch. Traumatic injuries, such as lacerations or dislocation, are associated with ankle or calcaneal fracture. Tendinopathy of the tibialis posterior occurs frequently in runners and is associated with valgus flatfoot-pronation deformities [3].

Posterior tibialis tendon deficiency is a presentation of this tendinopathy. The incidence is higher in middle-aged women who have coexisting obesity. Pain around the posteromedial aspect of the ankle, fatigue or weakness of the foot and ankle, and difficulty in walking are seen, and it can lead to flatfoot deformity [25].

Tibialis anterior tendon rupture is an uncommon disorder. The main clinical presentation is an atraumatic rupture in a man over the age of 45 years due to an eccentric loading of a degenerated tibialis anterior tendon against a plantar flexed ankle. Traumatic injuries occur in a laceration or blunt trauma. Pseudotumor at the anteromedial aspect of the ankle, loss of the contour of the tibialis anterior tendon, and the use of the extensor halluces longus and extensor digitorum communis to dorsiflex the ankle are the physical findings [26].

Peroneal tendon injuries are a common cause of pain in the lateral aspect of the ankle. These injuries also vary from traumatic situation, like after ankle sprain, or degenerative chronic disorders, often in patients with predisposing structural components such as hindfoot varus, lateral ligamentous instability, an enlarged peroneal tubercle, and a symptomatic os peroneum. The clinical presentation is a patient with pain, weakness with hindfoot eversion, and unstable gait [27, 28] (Fig. 39.2).

Fig. 39.2

Peroneal tenosynovitis

39.2.2 Imaging

The diagnosis of these lesions should always be based on the patient clinical condition. Imaging tests are used to confirm and describe these lesions, assisting in the therapeutic decision. Each exam has its indication and limitation, and in clinical practice they are completed. The radiographs are indicated in traumatic injuries to search for fractures that may be associated. In chronic cases, they can show tendinopathy alterations as osteophytosis. The MRI is useful for bone and soft tissue disorders. Ultrasonography (US) also can describe bone and soft tissue injuries in addition to revealing neovascularization in the pathologic tendon [20, 21, 29].

39.2.2.1 Radiography

Plain radiography is a fast and cost-effective way to identify a wide range of joint disorders. It is used to diagnose associated or incidental bony alteration [14, 20].

In the evaluation of extensor mechanism ruptures, the tendon may appear widened and indistinct, and a patellar displacement and avulsion fractures can be seen. So in a quadriceps tendon tear, the avulsion fragment originates from the patellar superior pole, and in a complete tear, the patella baja is seen. The opposite happens in the patellar tears. The patellar detachment is proximal and the avulsion fractures, which often are present, occur in the patellar lower pole [21, 30] (Fig. 39.3).

Fig. 39.3

Proximal patellar detachment in patellar tendon injury

Pires Albuquerque et al. [9] described the radiographic analysis of tendon tears in the knee extensor mechanism. The most prevalent abnormality was suprapatellar osteophytes alone, followed by alterations of infrapatellar calcification, suprapatellar calcification, and supra- and infrapatellar osteophytes. The most rare abnormality seen was the infrapatellar osteophytes alone. This alteration can be identified before the tears and indicate a prevention measures (Fig. 39.4).

Fig. 39.4

Osteophyte suprapatelar in the quadriceps tendinopathy

Radiographic of an Achilles tendon tear may show Kager’s triangle loss of its regular configuration. When it occurs, calcaneal tuberosity avulsion fractures are possible evidence [1].

Osteophytosis is a process of calcification and osseous metaplasia that occurs in chronic tendinosis. They also can be seen in plain radiography of the hip, knee, or foot and ankle with tendinopathy.

39.2.2.2 Ultrasonography

US is an important imaging method. It has a good cost-effectiveness, does not present a contraindication of radiation, and can be done in dynamic mode. However, the examination is operator dependent [14, 24].

Grayscale US is a conventional imaging technique that can show tendinopathy thickening and alterations in the tendon structure. In the tendon insertion on the bone, mucoide degeneration may be seen. Doppler sonography is another technique which is able to indicate the presence of neovessels in a degenerative tendon area. This neovascularization is frequent in patients symptomatic for pain [3].

There are indications of US such as in traumatic or non-traumatic and acute or chronic tendon injuries. The normal tendons appear hyperechoic (bright) on ultrasound although tendinopathy is a hypoechoic area. Rupture can be seen as an acoustic vacuum with thick and irregular edges [1, 24] (Fig. 39.5).

Fig. 39.5

Achilles tendon partial rupture

39.2.2.3 Magnetic Resonance Imaging

MRI is an excellent diagnostic tool to evaluate sports-related injuries involving the ligaments, tendons, menisci, osseous structures, and articular surfaces.

Knee disorders are the most frequent indications for MRI in the lower extremities. Routine protocols are sufficient for most pathologies of the extensor mechanism. Its integrity is best evaluated on T2-weighted sagittal MRI [20, 30, 31].

The quadriceps tendon is a multilaminar structure. Zeiss et al. [32] described the tendon as conjoined structure serving all the muscle groups combined; the most superficial layer arises from the rectus femoris muscle and the deepest layer from the vastus intermedius muscle. In this study, most tendons were composed by three layers, so that the intermediate layer is formed by the vastus lateralis and vastus medialis. Rarely cases where the tendon was seen as four thin layers or a convergence of all the layers like a single tendon band were found.

This laminated configuration is significant in the discrimination between partial and full tears. Discontinuity of any of these layers is consistent with a partial tear, and the insert of the rectus femoris tendon on the patellar superior pole is the most common site of disruption. A complete tendon rupture is seen when all layers tear and is associated with edematous tissue, hemorrhage, and retraction of the proximal fibers. The insertion of the quadriceps tendon at the patella upper pole is the typical area of rupture. In chronic overuse injury or tendinopathy of the quadriceps tendon, thickening and increased T2 signal are found in the MRI [20, 23, 31, 32] (Fig. 39.6).

Fig. 39.6

Quadriceps tendon partial rupture

Unlike the quadriceps tendon, the patellar tendon is a solid tendon, and the MRI demonstrates homogenous low signal intensity, may have a convex anterior border, and should always have a well-defined posterior border [31]. Yun et al. [19] published that the increased signal of the proximal patellar tendon on T1-weighted image and fluid-sensitive MRI results from invaginating fat, vessels, and perivascular connective tissue. It is not pathological but a normal and common finding. Jumper’s knee alterations in magnetic resonance imaging include a focal thickening of the proximal one-third of the tendon, an anterior-posterior diameter greater than 7 mm, and focal T2 hyperintensity located within the medial aspect of the tendon, near its patellar attachment. Others found indistinct posterior tendon border, edema in the adjacent Hoffa’s fat pad, and bone marrow edema within the adjacent inferior pole of the patella [20, 21, 23, 30, 31] (Fig. 39.7).

Fig. 39.7

Jumper’s knee with partial patellar tendon rupture

In chronic or neglected cases, the entire length of the patellar tendon may be involved, and the MRI shows a fusiform thickening of the tendon with altered signal intensity [20].

An acute patellar tear may be partial or full thickness. Fluid signal within the expected location is an indication of partial patellar tendon rupture. In complete disruption, imaging shows discontinuity of the patellar tendon, retraction of its fibers, hemorrhage that can extend to the Hoffa’s fat pad, and edema that can result in blurring of the posterior margin of the tendon [21, 31].

MRI of the Achilles tendon is useful to evaluate the various stages of chronic degeneration and in differentiating between peritendinitis and tendinopathy because it provides information on the internal morphology of the tendon and the surrounding structures. In Achilles tendon tears, the indications of this study are for preoperative planning in ambiguous presentations and subacute or chronic injuries [14]. Garras et al. [33] show that in acute Achilles tendon ruptures, the physical examination findings were more sensitive than MRI, which is time-consuming and expensive and can lead to treatment delays.

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