Published online before print May 17, 2002, 10.1148/radiol.2241011067
(Radiology 2002;224:112-119.)
© RSNA, 2002
Tennis Leg: Clinical US Study of 141 Patients and Anatomic Investigation of Four Cadavers with MR Imaging and US1
Gonzalo J. Delgado, MD2,
Christine B. Chung, MD,
Nitaya Lektrakul, MD,
Patricio Azocar, MD,
Michael J. Botte, MD,
Daniel Coria, MD,
Enrique Bosch, MD and
Donald Resnick, MD
1 From the Departments of Radiology (G.J.D., C.B.C., N.L., D.R.) and Orthopedic Surgery (M.J.B.), University of California, San Diego, Veterans Affairs Medical Center, 3350 La Jolla Village Dr, San Diego, CA 92161. Received June 18, 2001; revision requested August 10; revision received November 28; accepted December 19. Address correspondence to D.R. (e-mail: dresnick@ucsd.edu).
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ABSTRACT
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PURPOSE: To evaluate the ultrasonographic (US) findings in patients with a referring diagnosis of tennis leg and to explore the relative importance of the plantaris tendon and gastrocnemius muscle in the pathogenesis of this condition.
MATERIALS AND METHODS: A cadaveric study was performed to outline the normal anatomy of the posterosuperficial compartment of the calf. Magnetic resonance (MR) imaging and US were performed, followed by gross anatomic correlation. US findings in 141 patients referred with a clinical diagnosis of tennis leg were retrospectively reviewed by means of consensus of two radiologists. Images were analyzed with respect to the integrity of the lower-leg musculotendinous units, presence of fluid collection, and deep venous thrombosis.
RESULTS: MR imaging and US enabled distinction of the musculotendinous unit of the plantaris from the remaining muscles of the lower extremity in cadaveric specimens. US findings in the 141 patients included rupture of the medial head of the gastrocnemius muscle in 94 patients (66.7%), fluid collection between the aponeuroses of the medial gastrocnemius and soleus muscles without muscle rupture in 30 patients (21.3%), rupture of the plantaris tendon in two patients (1.4%), and partial rupture of the soleus muscle in one patient (0.7%). Deep venous thrombosis was seen in isolation in 14 patients (9.9%).
CONCLUSION: In patients with clinical findings of tennis leg who undergo US, abnormalities of the medial gastrocnemius muscle appear to be more common than those of the plantaris tendon.
© RSNA, 2002
Index terms: Athletic injuries, 45.489, 45.491 • Muscles, gastrocnemius, 45.489, 45.491 • Muscles, injuries, 45.489, 45.491 • Muscles, plantaris, 45.489, 45.491 • Tendons, injuries, 45.489, 45.491 • Tendons, MR, 45.121411
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INTRODUCTION
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Tennis leg is a relatively common clinical condition. The classic clinical manifestation is in a middle-aged person who complains of sport-related acute pain in the middle portion of the calf, associated with a snapping sensation (1,2). The pathogenesis of this condition has been debated since Powell first described it in 1883 (3). For several years, tennis leg was attributed to a rupture of the plantaris tendon. More recently, most investigators have implicated a rupture of the medial head of the gastrocnemius muscle at the musculotendinous junction in the pathogenesis of this entity (2,4,5). Some authors still question the role of the plantaris tendon in tennis leg (2,5); surgically proven cases of ruptures of the plantaris tendon or musculotendinous junction have been reported in conjunction with this clinical diagnosis (6,7). Hence, the controversy remains regarding the pathogenesis of tennis leg. Magnetic resonance (MR) imaging and ultrasonography (US) have been used as the primary imaging techniques for evaluation of patients with this clinical diagnosis. The importance of imaging patients with this condition is to rule out more serious conditions, such as deep venous thrombosis (7–10).
The purpose of this study was twofold: (a) to evaluate in cadavers the anatomy of the muscles and tendons of the posterosuperficial compartment of the leg by using both MR imaging and US, emphasizing the plantaris muscle and its tendon, and (b) to evaluate US findings in 141 patients with a clinical diagnosis of tennis leg to define the relative involvement of the plantaris tendon and gastrocnemius muscle in the pathogenesis of this condition.
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MATERIALS AND METHODS
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Anatomic Considerations
The plantaris muscle is part of the posterosuperficial compartment of the calf. Together with the gastrocnemius and soleus muscles, it forms the triceps surae muscle (Fig 1). The plantaris consists of a small muscle belly with a thin, long tendon (Fig 2). The muscle originates from the lateral supracondylar line just superior and medial to the lateral head of the gastrocnemius muscle. As it courses distally, the plantaris muscle belly lies just deep to the lateral head of the gastrocnemius muscle in the posterior aspect of the proximal leg. The long and slender plantaris tendon continues distally, following an oblique course, to the medial aspect of the lower extremity, where it is located between the medial head of the gastrocnemius muscle and the soleus muscle in the midportion of the calf. Distally, the plantaris tendon is located near the medial border of the Achilles tendon, inserting on the calcaneus anteromedial to the Achilles tendon. In some cases, it fuses with the Achilles tendon. The plantaris muscle, like the gastrocnemius muscle, spans two joints: the knee and the ankle. Cadaveric studies have revealed that the plantaris muscle is absent in 7%–20% of limbs. When absent on one side, it is absent in the contralateral side in 67% of persons (11).
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Figure 1a. (a) Schematic drawing of the posterior aspect of the lower leg shows components of the posterosuperficial compartment of the calf. (b) Photograph of a dissected cadaveric leg shows the level of interest in tennis leg, the musculotendinous junction of the medial head of the gastrocnemius muscle (arrows) with adjacent plantaris tendon (arrowheads).
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Figure 1b. (a) Schematic drawing of the posterior aspect of the lower leg shows components of the posterosuperficial compartment of the calf. (b) Photograph of a dissected cadaveric leg shows the level of interest in tennis leg, the musculotendinous junction of the medial head of the gastrocnemius muscle (arrows) with adjacent plantaris tendon (arrowheads).
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Figure 2. Photograph of a dissected cadaveric leg shows the plantaris muscle and tendon. Muscle belly (arrows) has been detached from its proximal insertion, and the long plantaris tendon (arrowheads) is displayed.
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Anatomic Study
Four human legs were obtained from nonembalmed fresh cadavers (four men; age range at time of death, 78–86 years; mean age, 80.2 years) and were immediately deep-frozen at -40°C (Bio-Freezer; Forma Scientific, Marietta, Ohio). The specimens were allowed to thaw for 36 hours at room temperature prior to imaging.
US was performed with an HDI 5000 unit (Advanced Technology Laboratories, Bothell, Wash) with a 5–12-MHz broadband electronic linear-array transducer by an investigator (G.J.D.) experienced in performing musculoskeletal US. The posterior lower extremity was evaluated in the longitudinal and transverse planes, with particular attention to the plantaris muscle and tendon with regard to cephalocaudal orientation, relationship to surrounding muscles and tendons, and US characteristics, including echotexture, fibrillar pattern in the longitudinal plane, and transverse shape.
Subsequently, T1-weighted spin-echo MR images of the four cadaveric legs were obtained with a 1.5-T superconducting MR imager (Signa; GE Medical Systems, Milwaukee, Wis). The specimens were placed in the supine position with the knee in extension. A receive-only dedicated knee coil was used for image acquisition. Images were obtained in the transverse, sagittal, and coronal planes. The transverse images were obtained from the metadiaphyseal region of the femur to the calcaneus. In each specimen, images were obtained in the sagittal and coronal planes at the level of the knee. The T1-weighted spin-echo sequences were performed with the following parameters: 500/20 (repetition time msec/echo time msec), two signals acquired, 16-cm field of view, 512 x 256 imaging matrix, and 3–4-mm section thickness with a 1-mm intersection gap.
After imaging, the specimens were frozen again for more than 72 hours. Three of them were sectioned with a band saw in planes corresponding to those of the MR images. One of the specimens was dissected by an orthopedic surgeon (M.J.B.) to portray the gross anatomy of the plantaris muscle and tendon.
The MR images and gross anatomic specimens of each leg were evaluated simultaneously by means of consensus of two radiologists (G.J.D., C.B.C.) to compare and better understand the morphology of the plantaris muscle and tendon, as well as the anatomic relationship with surrounding structures at the upper, middle, and distal thirds of the leg at MR imaging.
Clinical Study
A retrospective review of patient history and demographics was performed for 301 consecutive patients who underwent US examinations of the lower extremity during a 20-month period (November 1, 1998, through June 30, 2000). Of these 301 patients, 141 (109 men, 32 women; age range, 22–82 years; mean age, 45 years) with a clinical diagnosis of tennis leg were referred by a variety of physicians (eg, orthopedic surgeons and emergency medicine physicians). Patients were seen in the hospital an average of 3.6 days (range, 1–35 days) after the onset of clinical symptoms. US images of these 141 patients were reviewed retrospectively by means of consensus of two musculoskeletal radiologists (G.J.D., C.B.C.) who were not blinded with respect to clinical history or purpose of the study. Images were examined with particular attention to the presence of muscle tear, tendon rupture, fluid collection, and deep venous thrombosis in the calf. Our institutional review board does not require its approval or informed patient consent for this type of retrospective study.
All US examinations were performed with either an HDI 5000 or 3000 machine (Advanced Technology Laboratories) with a 4.0–7.5-MHz or 5.0–12.0-MHz broadband linear-array transducer. Examinations had been performed originally by one of three radiologists at a single institution. Patients were placed in the prone position, emphasizing the longitudinal and transverse planes for analysis. In each case, the opposite lower extremity was also examined for comparison only (informational analysis was not performed). At retrospective review, diagnosis of a partial muscular rupture was based on the presence of a localized disruption or discontinuity of the muscular fibers, whereas a complete rupture was defined as a lesion that involved the entire muscle. A complete plantaris tendon rupture was diagnosed when total discontinuity in the tendon was demonstrated, with visualization of the gap or retraction of the proximal myotendinous junction. Fluid collection between the aponeuroses of the medial gastrocnemius and soleus muscles was defined as an accumulation of anechoic or hypoechoic material in this location. The criteria for diagnosis of deep venous thrombosis included no compressibility of the vein (as documented by the generated report and annotated images), echogenic material inside its lumen, and absence of flow signal at Doppler examination (information obtained from the US images).
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RESULTS
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Anatomic Study
MR imaging.—In all four cadaveric specimens, MR imaging demonstrated the intimate relationship of the origins of the muscles of the posterior lower extremity, as well as the complex course of the plantaris tendon. The plantaris muscle took its origin from the lateral supracondylar femoral line just superior to the origin of the lateral head of the gastrocnemius muscle. The origins of these two structures were best demonstrated on transverse and coronal images (Fig 3).
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Figure 3a. (a) Coronal T1-weighted 500/20 MR image obtained at the posterior aspect of a cadaveric knee and (b) coronal anatomic section of the same specimen. The proximal portion of the plantaris muscle near its origin (straight arrows) is located medial to the lateral head of the gastrocnemius muscle and plantaris tendon (arrowheads). An os fabella (curved arrow) is present in the tendon of the last muscle. Fibular head (F) and biceps femoris muscle and tendon (open arrows) are shown.
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Figure 3b. (a) Coronal T1-weighted 500/20 MR image obtained at the posterior aspect of a cadaveric knee and (b) coronal anatomic section of the same specimen. The proximal portion of the plantaris muscle near its origin (straight arrows) is located medial to the lateral head of the gastrocnemius muscle and plantaris tendon (arrowheads). An os fabella (curved arrow) is present in the tendon of the last muscle. Fibular head (F) and biceps femoris muscle and tendon (open arrows) are shown.
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Just distal to the origin of the plantaris muscle and the lateral head of the gastrocnemius muscle, the latter muscle became more elliptical in shape with a convex medial margin, which was located superficial to the plantaris muscle. At the level of the proximal third of the leg, the plantaris muscle demonstrated a triangular shape in the transverse plane and was located between the popliteus muscle anteriorly and the lateral head of the gastrocnemius muscle posteriorly (Fig 4). The musculotendinous junction of the plantaris was located approximately at the junction of the proximal one-third and distal two-thirds of the lower extremity. The plantaris muscle had completed its course to the medial aspect of the lower extremity and its tendon at the level of the middle third of the leg. The tendon was located between the soleus muscle anteriorly and the medial head of the gastrocnemius muscle posteriorly. It was visualized in the transverse plane as a small ovoid structure of low signal intensity in this location (Fig 5). At the level of the distal third of the leg, the tendon continued distally and became difficult to distinguish from the Achilles tendon until its independent calcaneal insertion (Fig 6).
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Figure 4a. (a) Transverse T1-weighted (500/20) MR image obtained at the level of the proximal tibia in a cadaveric leg and (b) transverse anatomic section of the same leg. The plantaris muscle (arrows) lies between the lateral head of the gastrocnemius muscle (G) posteriorly and the popliteus muscle (PO) anteriorly.
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Figure 4b. (a) Transverse T1-weighted (500/20) MR image obtained at the level of the proximal tibia in a cadaveric leg and (b) transverse anatomic section of the same leg. The plantaris muscle (arrows) lies between the lateral head of the gastrocnemius muscle (G) posteriorly and the popliteus muscle (PO) anteriorly.
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Figure 5a. (a) Transverse T1-weighted (500/20) MR image obtained at the level of the middle third of the calf in a cadaveric leg and (b) transverse anatomic section of the same leg. On the MR image, a small plantaris tendon (arrows) is visualized with low signal intensity between the medial heads of the gastrocnemius (G) and soleus (S) muscles.
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Figure 5b. (a) Transverse T1-weighted (500/20) MR image obtained at the level of the middle third of the calf in a cadaveric leg and (b) transverse anatomic section of the same leg. On the MR image, a small plantaris tendon (arrows) is visualized with low signal intensity between the medial heads of the gastrocnemius (G) and soleus (S) muscles.
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Figure 6a. (a) Transverse T1-weighted (500/20) MR image obtained at the level of the ankle in a cadaveric leg and (b) photograph of the same dissected leg. The plantaris tendon is difficult to differentiate from the Achilles tendon (A) on the MR image. The plantaris tendon is probably represented by a small "comet tail" structure (arrow in a) at the medial edge of the Achilles tendon; at dissection, however, the independent relationship between the tendons (probe is placed under the plantaris tendon) is clearly demonstrated.
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Figure 6b. (a) Transverse T1-weighted (500/20) MR image obtained at the level of the ankle in a cadaveric leg and (b) photograph of the same dissected leg. The plantaris tendon is difficult to differentiate from the Achilles tendon (A) on the MR image. The plantaris tendon is probably represented by a small "comet tail" structure (arrow in a) at the medial edge of the Achilles tendon; at dissection, however, the independent relationship between the tendons (probe is placed under the plantaris tendon) is clearly demonstrated.
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US imaging.—The plantaris muscle, myotendinous junction, and proximal tendon demonstrated an oblique cephalocaudal course in the leg laterally to medially. The proximal portion of the plantaris muscle belly, as well as its origin, was difficult to visualize and differentiate from the lateral head of the gastrocnemius muscle with this method in all four specimens, although the musculotendinous junction and tendon were well demonstrated with this method. The longitudinal plane proved to be the best for the evaluation of the plantaris musculotendinous junction and tendon, which were well demonstrated in all four specimens. In the longitudinal plane, at the proximal third of the calf, the musculotendinous junction was fusiform in shape and was situated between the gastrocnemius and soleus muscles (Fig 7), in continuity with the tendon distally. At a lower level, the plantaris tendon was visualized in the longitudinal plane as a thin, echogenic fibrillar structure lying between the medial head of the gastrocnemius and soleus muscles. The plantaris tendon was located adjacent to the medial aspect of the musculotendinous junction of the gastrocnemius muscle. In the tranverse plane, the tendon was visualized as a small ovoid structure (Fig 8). Distally, it lay adjacent to and was difficult to distinguish from the medial side of the Achilles tendon, until its insertion in the calcaneus.
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Figure 7a. (a) Longitudinal US image obtained at the proximal calf in a cadaveric leg and (b) photograph of the same dissected specimen. The musculotendinous junction has a fusiform shape at US and gross photography. The plantaris muscle belly (arrows) and proximal plantaris tendon (arrowheads) are shown.
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Figure 7b. (a) Longitudinal US image obtained at the proximal calf in a cadaveric leg and (b) photograph of the same dissected specimen. The musculotendinous junction has a fusiform shape at US and gross photography. The plantaris muscle belly (arrows) and proximal plantaris tendon (arrowheads) are shown.
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Figure 8a. (a) Longitudinal and (b) transverse US images obtained at the level of the middle calf in the same cadaveric leg shown in Figure 7. The plantaris tendon (arrows) is identified as a long, fibrillar, echogenic, and small ovoid structure in the (a) longitudinal and (b) transverse planes. It is located between the medial heads of the gastrocnemius (G) and soleus (S) muscles.
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Figure 8b. (a) Longitudinal and (b) transverse US images obtained at the level of the middle calf in the same cadaveric leg shown in Figure 7. The plantaris tendon (arrows) is identified as a long, fibrillar, echogenic, and small ovoid structure in the (a) longitudinal and (b) transverse planes. It is located between the medial heads of the gastrocnemius (G) and soleus (S) muscles.
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Cadaveric dissection.—The cadaveric study confirmed the presence of the plantaris muscle and tendon in all four cadaveric legs. The leg that was dissected demonstrated the close spatial relationship between the plantaris tendon and the internal aspect of the myotendinous junction of the medial head of the gastrocnemius muscle at the middle third of the calf (Fig 2). The plantaris muscle had a triangular shape, with its base oriented to medial, and measured 9.5 cm in the longitudinal axis and 3.4 cm in the widest transverse axis. The slender plantaris tendon was 20 cm long, and it attached in the calcaneus independently from the Achilles tendon. The plantaris was also present in all three sectioned cadaveric specimens.
Clinical Study
With regard to US findings in the 141 patients referred with clinical findings of tennis leg, partial rupture of the medial head of the gastrocnemius muscle at or no more than 2 cm from the myotendinous junction, without rupture of the plantaris tendon, was identified in 94 patients (66.7%) (Fig 9). Of these 94 patients, 59 (62.8%) had associated fluid collection between the medial head of the gastrocnemius muscle and the soleus muscle. Fluid collection between the aponeuroses of the gastrocnemius and soleus muscles, without US evidence of rupture of the triceps surae musculotendinous unit, was evident with US in 30 patients (21.3%) (Fig 10). Rupture of the plantaris tendon was seen in two patients (1.4%) at the middle third of the leg (Fig 11), and a partial rupture of the soleus muscle was seen in one patient (0.7%). Deep venous thrombosis was seen in isolation in 14 patients (9.9%) and in association with another finding in seven patients (5.0%) (Fig 12); in six of these seven patients, fluid collection between the aponeuroses was evident without evidence of rupture of the triceps surae, and in one patient, a rupture of the medial head of the gastrocnemius muscle was observed. These results are summarized in the Table.
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Figure 9. Longitudinal US image shows a partial tear of the medial head of the gastrocnemius muscle at the musculotendinous junction in a 32-year-old man with a history of tennis leg. Image shows the medial head of the gastrocnemius muscle (G) with partial discontinuity of muscle fibers at the myotendinous junction (straight arrows). Small hypoechoic collection (curved arrows) is noted, which extends distally, superficial to the soleus muscle (S).
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Figure 10. Longitudinal US image obtained at the medial aspect of the calf in a 34-year-old man with a clinical history of tennis leg. Image shows hypoechoic fluid collection (C) between the medial heads of the gastrocnemius (G) and soleus (S) muscles. No US evidence of disruption of the medial head of the gastrocnemius muscle or plantaris tendon (arrows) was found.
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Figure 11. Longitudinal US image obtained at the medial aspect of the calf shows complete rupture of the plantaris tendon in a 37-year-old man. Image shows total discontinuity of the plantaris tendon (straight arrows), which is retracted proximally. Laminar fluid (curved arrows) is visualized between the medial heads of the gastrocnemius (G) and soleus (S) muscles.
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Figure 12a. US images obtained in a 41-year-old woman show deep venous thrombosis as a complication of tennis leg. (a) Longitudinal US image shows a small partial rupture at the musculotendinous junction of the medial head of the gastrocnemius muscle (G) (arrows). Soleus (S) is noted for orientation. (b) Transverse color Doppler image (black and white version shown) of the calf of the same patient as in a shows a dilated vein (straight arrows) that was not compressible and had echogenic material in its lumen and absent flow signal at color Doppler examination. Flow signal is present in an adjacent small vein (curved arrow).
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Figure 12b. US images obtained in a 41-year-old woman show deep venous thrombosis as a complication of tennis leg. (a) Longitudinal US image shows a small partial rupture at the musculotendinous junction of the medial head of the gastrocnemius muscle (G) (arrows). Soleus (S) is noted for orientation. (b) Transverse color Doppler image (black and white version shown) of the calf of the same patient as in a shows a dilated vein (straight arrows) that was not compressible and had echogenic material in its lumen and absent flow signal at color Doppler examination. Flow signal is present in an adjacent small vein (curved arrow).
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DISCUSSION
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Tennis leg is a clinical condition first described by Powell in 1883 (3). It is an entity that typically occurs in middle-aged persons, often related to an injury incurred with extension of the knee and forced dorsiflexion of the ankle (1,2). Although it has been described as a result of mainly sports-related activities, in our experience tennis leg also commonly results from daily activities, such as running to catch a bus or climbing stairs. Sudden pain is felt in the calf, and patients often report a "pop" in the calf or a feeling as though someone has kicked the back of their leg. Substantial pain and swelling usually develop during the following 24 hours. The treatment of this condition is usually conservative, with elevation of the lower extremity, application of ice, and use of supportive elastic dressings. Surgical treatment (fasciotomy) is indicated only when an associated compartmental syndrome has complicated the evolution of the symptoms and signs (2,12).
The pathogenesis of tennis leg has been debated since Powell’s report (3). Initially, this condition was believed to arise from a rupture of the plantaris tendon in the medial aspect of the calf. In 1958, Arner and Lindholm (12) refuted this hypothesis after surgical exploration in five of 20 patients with a diagnosis of tennis leg. In each of these patients, a rupture of the medial head of the gastrocnemius muscle at the musculotendinous junction, without injury to the plantaris muscle or tendon, was discovered. Descriptions of tennis leg have implicated a tear of the medial head of the gastrocnemius muscle, especially at the musculotendinous junction, as the usual pathogenesis of tennis leg (2,5,10,14). Biomechanical investigations of the gastrocnemius muscle have shown it to be particularly vulnerable to injury; this muscle is histologically a "fast-action" muscle with type IIb muscle fibers, and it spans two joints—the knee and the ankle (12).
Although the role of the plantaris muscle and tendon in cases of tennis leg has been questioned, and, indeed, some authors have considered rupture of the plantaris tendon to be a myth without scientific support (2,4,5), there are at least two reported cases of surgically confirmed ruptures of the plantaris tendon in patients with tennis leg (6,7). MR imaging has been used to depict lesions of the plantaris muscle and musculotendinous junction (7,8,15). In one study (9), plantaris tendon ruptures were evaluated with US, and tendon tears were more commonly found distal to the musculotendinous junction. It is believed that the precise location of the lesion along the plantaris muscle may reflect a specific mechanism of injury; plantaris muscle belly rupture or strain has been noted in association with traumatic lesions of the knee, such as anterior cruciate ligament ruptures and lesions in the posterolateral corner (8,16), whereas ruptures at the level of the plantaris tendon or musculotendinous junction have been found to occur in isolation (7,8) and to be related to tennis leg.
Despite the controversy with regard to the pathogenesis of tennis leg, to our knowledge there are no previous articles concerning the relative importance of lesions of the plantaris tendon and medial head of the gastrocnemius muscle in patients with this condition. Results of our study have demonstrated that rupture of the medial head of the gastrocnemius muscle appears to be more common than that of the plantaris tendon and soleus muscle. Our results also demonstrated that rupture of other components of the posterosuperficial compartment of the leg can lead to clinical findings that simulate those associated with disruption of the medial head of the gastrocnemius muscle.
Fluid collection between the aponeuroses of the medial heads of the gastrocnemius and soleus muscles has been noted in cases of disruption of the medial head of the gastrocnemius muscle (10,16,17), as well as in cases of plantaris rupture, especially at the level of the muscle belly or musculotendinous junction (8,9,16). This fluid collection has been considered to most likely represent a secondary hematoma (10); however, investigators in one report note that fluid collection in this location in patients with tennis leg is not hemorrhagic in origin but is more likely pseudocystic (17). In our study, the presence of fluid collection in this location was a common finding in patients with rupture of the medial head of the gastrocnemius muscle, occurring in more than 50% of these patients. The presence of fluid collection, without US evidence of rupture of the other component of the triceps surae, was not an uncommon finding. Although none of the fluid collections were evacuated in our patients, we believe that a hematoma would be unlikely with disruption of the plantaris tendon, because, like all tendons, it is an avascular structure. It seems more probable that a hematoma would develop with a rupture of the more vascular medial head of the gastrocnemius muscle. In this regard, Bianchi et al (10) reported difficulty in depicting small ruptures in the anteromedial portion of the medial head of the gastrocnemius muscle with US. We cannot exclude that some of these fluid collections could represent a ruptured Baker cyst.
Findings related to deep venous thrombosis in the calf can be mistaken for those of tennis leg (9,10). In our series, deep venous thrombosis was seen in isolation in 14 patients and in association with other findings in seven patients. Therefore, deep venous thrombosis must be kept in mind in the differential diagnosis of clinical findings suggestive of tennis leg, and venous structures of the calf should be examined routinely to rule out thrombosis as a complication in patients with tennis leg.
Our study has several limitations, including the retrospective evaluation of US images. None of our patients underwent surgery to confirm the diagnosis, and no other imaging examinations were performed to confirm the US findings. In this regard, no patients underwent MR imaging because of the high cost and low availability at our institution. We did not have access to follow-up clinical information on our patients because most of them received additional consultations at other institutions. The group of referring clinicians was heterogeneous and included orthopedic surgeons, orthopedic surgery residents, and emergency medicine physicians.
In conclusion, in patients with clinical findings of tennis leg who undergo US, abnormalities of the medial head of the gastrocnemius muscle appear to be more common than those of the plantaris tendon. Deep venous thrombosis can mimic or complicate tennis leg. US is an effective imaging method for the evaluation of patients with clinical findings suggestive of tennis leg.
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ACKNOWLEDGMENTS
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The authors thank Julio Rosales, MD, for help in the data acquisition for the clinical study, and Debra Trudell, RA, for technical assistance in preparing the cadaveric specimens and acquiring the MR images.
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FOOTNOTES
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2 Current address: Radiology Service, Hospital del Trabajador, Santiago, Chile. 
Author contributions: Guarantors of integrity of entire study, G.J.D., C.B.C., D.R.; study concepts, D.R.; study design, M.J.B., G.J.D., C.B.C., P.A.; literature research, N.L., G.J.D.; clinical studies, G.J.D., P.A., D.C., E.B.; experimental studies, G.J.D., C.B.C., M.J.B.; data acquisition, G.J.D., P.A., D.C., C.B.C.; data analysis/interpretation, G.J.D., C.B.C., D.R.; statistical analysis, G.J.D., P.A.; manuscript preparation, G.J.D., C.B.C., N.L.; manuscript definition of intellectual content, D.R., C.B.C., G.J.D.; manuscript editing, G.J.D., C.B.C., D.R.; manuscript revision/review, G.J.D., E.B., C.B.C., D.R.; final version approval, E.B., G.J.D., C.B.C., D.R.
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REFERENCES
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- Froimson AE. Tennis leg. JAMA 1969; 209:415-416.[CrossRef][Medline]
- Gilbert TJ, Bullis BR, Griffiths HJ. Tennis calf or tennis leg. Orthopedics 1996; 19:179-184.[Medline]
- Powell RW. Lawn tennis leg. Lancet 1883; 2:44.[CrossRef]
- Miller WA. Rupture of the musculotendinous juncture of the medial head of the gastrocnemius muscle. Am J Sports Med 1977; 5:191-193.[Free Full Text]
- Severance HJ, Bassett FH, III. Rupture of the plantaris: does it exist? J Bone Joint Surg Am 1982; 64:1387-1388.[Free Full Text]
- Mennen U. Rupture of the plantaris: does it exist? (letter). J Bone Joint Surg Am 1983; 65:1030.[Free Full Text]
- Hamilton W, Klostermeier T, Lim E, Moulton JS. Surgically documented rupture of the plantaris muscle: a case report and literature review. Foot Ankle Int 1977; 18:522-523.
- Helms CA, Fritz RC, Garvin GJ. Plantaris muscle injury: evaluation with MR imaging. Radiology 1995; 195:201-203.[Abstract/Free Full Text]
- Leekam RN, Agur AM, McKee NH. Using sonography to diagnose injury of plantaris muscle and tendons. AJR Am J Roentgenol 1999; 172:185-189.[Free Full Text]
- Bianchi S, Martinoli C, Abdelwahab IF, Derchi LE, Damiani S. Sonographic evaluation of tears of the gastrocnemius medial head ("tennis leg"). J Ultrasound Med 1998; 17:157-162.[Abstract]
- Simpson SL, Hertzog MS, Barja RH. The plantaris tendon graft: an ultrasound study. J Hand Surg [Am] 1991; 16:708-711.[Medline]
- Arner O, Lindholm A. What is tennis leg? Acta Chir Scand 1958; 116:73-75.[Medline]
- Menz M, Lucas G. MRI of a rupture of the medial head of the gastrocnemius muscle: a case report. J Bone Joint Surg Am 1991; 73:1260-1262.[Free Full Text]
- DeLee JC, Drez D, Jr, eds. Orthopaedic sports medicine Philadelphia, Pa: Saunders, 1994; 1621.
- Allard JC, Bancroft J, Porter G. Imaging of plantaris muscle rupture. Clin Imaging 1992; 16:55-58.[CrossRef][Medline]
- Bencardino JT, Rosenberg ZS, Brown RR, Hassankhani A, Lustrin ES, Beltran J. Traumatic musculotendinous injuries of the knee: diagnosis with MR imaging. RadioGraphics 2000; 20:103-120.
- Guillodo Y, Botton E, Saraux A, Le Goff P. Effusion between the aponeuroses (letter). J Ultrasound Med 1999; 18:860-861.[Medline]
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H. Song, K. Nakazato, and H. Nakajima
Effect of Increased Excursion of the Ankle on the Severity of Acute Eccentric Contraction-Induced Strain Injury in the Gastrocnemius: An In Vivo Rat Study
Am. J. Sports Med.,
July 1, 2004;
32(5):
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[Abstract]
[Full Text]
[PDF]
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ABSTRACT
INTRODUCTION
