|Year : 2015 | Volume
| Issue : 4 | Page : 120-126
Can ultrasonography distinguish between complete and partial rupture of the Achilles tendon? A sonographic operative correlation
Hesham El Sheikh1, Wael Azzam MD 2
1 Department of Diagnostic Radiology, Faculty of Medicine, Benha University, Benha, Egypt
2 Department of Orthopedic Surgery, Faculty of Medicine, Tanta University Hospital, Tanta University, Tanta, Egypt
|Date of Submission||16-Jul-2015|
|Date of Acceptance||18-Aug-2015|
|Date of Web Publication||30-Oct-2015|
Department of Orthopedic Surgery, Faculty of Medicine, Tanta University Hospital, Tanta University, El-Geish Street, 31111 Tanta
The aim of the study was to assess the capability of ultrasonography (US) to differentiate between complete and partial rupture of the Achilles tendon by comparing preoperative US with intraoperative findings.
Patients and methods
We compared US and operative findings in 47 patients with US diagnosis of Achilles tendon rupture. US assessed the continuity and thickness of the tendon and paratendon and the presence of hematoma or bone fragments within the tendon.
Surgery confirmed complete rupture in all 29 tendons thought to be completely ruptured on US (accuracy = 100%) and confirmed partial rupture in 15 of the 18 tendons thought to be partially ruptured on US (accuracy = 83.3%); the remaining three cases showed retracted tendons with accompanying tendon tear consistent with complete rupture. The characteristic findings for complete tendon rupture were break of the tendon and paratendon, nonvisualization of the tendon, and the presence of gap (hematoma) or bone fragments within the tendon. The characteristic findings for partial tendon rupture were break of the tendon with intact paratendon, intact tendon with internal hypoechogenicity (tear), and tendon thickening.
US may help to distinguish partial from complete rupture of the Achilles tendon allowing for more appropriate patient management.
Keywords: Achilles tendon, complete rupture, partial rupture, ultrasound
|How to cite this article:|
Sheikh HE, Azzam W. Can ultrasonography distinguish between complete and partial rupture of the Achilles tendon? A sonographic operative correlation. Tanta Med J 2015;43:120-6
|How to cite this URL:|
Sheikh HE, Azzam W. Can ultrasonography distinguish between complete and partial rupture of the Achilles tendon? A sonographic operative correlation. Tanta Med J [serial online] 2015 [cited 2020 Nov 30];43:120-6. Available from: http://www.tdj.eg.net/text.asp?2015/43/4/120/168727
| Introduction|| |
The Achilles tendon is the largest and strongest tendon in the body  . Gastrocnemius and soleus muscles, the main plantar flexors of the ankle, contribute to the Achilles tendon. The Achilles tendon is inserted into the central part of the posterior surface of the calcaneus, and the narrowest part of the tendon is ~4 cm above the insertion. The tendon has no true synovial sheath but is instead covered by a paratendon, a thin layer of loose areolar tissue that acts to reduce friction and supplies the tendon with blood through its length as it is highly vascularized. There is one superficial and one deep bursa at the distal part of the tendon , .
The rupture is the most common Achilles tendon pathology  . Studies have reported an increasing incidence thought to be related to a greater interest in sports activities; the highest incidence of rupture occurs between the ages of 30 and 49 years, but there is a second peak in elderly nonathletes , . There is a greater risk of sustaining an Achilles tendon rupture in men than in women, with a male/female ratio ranging between 2 : 1 and 18 : 1  . The most common rupture type is the so-called subcutaneous rupture, in the midsubstance of the Achilles tendon - that is, 2-6 cm proximal to the insertion to the calcaneus - and the most common injury mechanism is a sudden, forced ankle dorsiflexion  . The etiology of Achilles tendon ruptures is still not well known and some factors suggested to be linked to Achilles tendon rupture are aging of the tendon, vascular impairments, and lifestyle factors  . At rest, the tendon fibers display a wavy configuration that disappears when the tendon is stretched ~2%. Up to ~4% elongation, the tendon will return to its original state after the tension is released. If the tendon is stressed beyond ~4% of its length, partial rupture will occur and, at ~8% of elongation, a complete rupture will occur  .
The diagnosis of acute Achilles tendon rupture is based on a standardized clinical examination  . Patients complain of calf pain and have a characteristic limp, because of the inability to do plantar flexion. Acute rupture of the tendon is characterized by a palpable tendon gap and a positive Thompson's calf squeeze test (squeezing the calf results in a failure to achieve plantar flexion) and a palpable retromalleolar hematoma occurs in most cases  .
Ultrasonography (US) of the Achilles tendon with linear probes produces a dynamic and panoramic image of the tendon  . The tendon is composed of longitudinally arranged collagen bundles and a normal Achilles tendon appears as a hypoechogenic, ribbon-like image that is contained within two hyperechogenic bands (paratendon). Tendon fascicles appear as alternate hypoechogenic and hyperechogenic bands that are separated when the tendon is relaxed and are more compact when the tendon is strained , . Rupture of the Achilles tendon is seen on US as an interruption of the tendon continuity by one or more hypoechoic or echo-free clefts or gaps within a tendon, indicating the formation of hematoma at the site of the rupture ,,,,, .
Controversy still remains about whether surgical or nonsurgical treatment is the best option to treat patients with Achilles tendon rupture  . Surgical treatment could reduce the risk of rerupture but might also lead to a high rate of postoperative complications such as infections, adhesions, and other wound-related problems , . In contrast, conservative treatment is thought to be advantageous in that there is a lower rate of complications but its disadvantage is a higher incidence of rerupture , . With regard to the time to return to work, surgical treatment results in an early return to work , . The best treatment for each individual patient is a weighing of the risk for a rerupture against the risk of complications and time to return to work , . However, the ability to determine the type of rupture of the Achilles tendon preoperatively is one of the parameters that could be of importance for the planning of the treatment regimen, as partial rupture can be treated conservatively , . As a result, there is a need to develop methods that have the ability to confirm the diagnosis of acute Achilles tendon rupture and to define the type of tendon rupture. For this reason, we decided to assess the capability of US to differentiate partial from complete rupture of the Achilles tendon to define whether the treatment should be surgical or conservative by comparing preoperative US with direct intraoperative findings. This topic is not addressed separately in previous studies.
| Patients and methods|| |
Fifty-one patients with a clinically suspicious Achilles tendon rupture were examined by US during the period between July 2011 and August 2014. US suggested Achilles tendon rupture in 49 patients of whom 47 patients underwent surgical tendon exploration and two patients refused surgery and all four patients were excluded from the study (two patients with negative US diagnosis of rupture and two patients who refused surgery). As a result, this study included 47 patients, 41 were male and six were female, and their ages ranged from 17 to 55 years, with a mean age of 33 years.
Patients were referred for US evaluation after careful clinical examination by the orthopedic surgeon. The clinical diagnosis was established on the basis of medical history and clinical examination (tendon palpation and Thompson's test). All patients complained of calf pain, and clinical examination showed positive Thompson's test in all patients (squeezing the calf results in weakness in, or failure to achieve, plantar flexion) and a retromalleolar hematoma in 22 patients.
The sonographic studies were performed prospectively by an experienced radiologist using a scanner (Mindray DC-7; Mindray, Shenzhen, China) with a 5-12-MHz linear-array transducer. Patients were examined in the prone position, with the ankle in the neutral position. The Achilles tendon was scanned in longitudinal and transverse projections in a static view, as well as in a dynamic view, during flexion and extension of the ankle to evaluate the tear of the ruptured tendon. The longitudinal view was obtained first to provide a survey of overall tendon architecture and the whole length of the tendon and its attachment to the calcaneus. The transducer was placed perpendicular to the tendon throughout its course to avoid refractive artifacts. The transverse scan provided a cross-sectional view of the tendon and muscles, as well as their relations and thickness. Focused attention was always directed at the site of maximum patient complaint. US assessed the continuity of the tendon and paratendon, the thickness of the tendon, and the presence of gap (hematoma) or bone fragments within the tendon at the site of rupture (the bone fragment appears as an echogenic structure that may cast posterior shadowing).
Achilles tendon rupture was easily seen in the longitudinal scan as an interruption of the tendon continuity by one or more hypoechoic or echo-free clefts or gaps within a tendon, indicating the formation of hematoma, which may or may not extend to the tendon's peripheral surface at the site of the rupture ,,,,, . The sonographic criteria compatible with a complete tendon rupture include nonvisualization of the tendon in the absence of surgery or break in the continuity of the tendon and paratendon ,,,,, . The sonographic criteria compatible with a partial tendon rupture include break of the tendon fibers but without a visible break in the continuity of the paratendon or local tendon thickening with intrasubstance focal or linear hypoechogenicity ,,,,, .
The contralateral asymptomatic tendon also was evaluated in all cases to provide a comparison of normal. These tendons were not explored at surgery and therefore were not included in the data.
US was performed no earlier than 12 h before the operation and the patient was hospitalized immediately; thus, there was no possibility of rerupture between the US examination and surgery. The operative decision was based on clinical parameters.
Surgery was performed with the patient in the prone position under spinal (n = 37) or general anesthesia (n = 10). A tourniquet was used for homeostasis in all cases. After a longitudinal 5-8 cm skin and paratendon incision, direct repair with Ethibond Excel (Ethicon, Norderstedt, Germany) suture was performed in 38 cases [Figure 1] and [Figure 2]. In nine (19.15%) cases where direct repair was not possible due to a large tendon defect after debridement, V-Y myotendinous advancement to close the tendon gap was performed in two cases and flexor hallucis longus tendon transfer for tendon reconstruction in seven cases  .
|Figure 1: (a-c) Acute complete rupture of the distal-third of the Achilles tendon with an avulsed bone fragment. Longitudinal ultrasonography image (a) shows break of continuity of the tendon and paratendon just above the insertion of the tendon on the posterior surface of the calcaneus (calc.) with hypoechoic 'mass-like' structure within the substance of the tendon suggested to be hematoma (short arrows). Note the presence of bone fragment avulsed from the calcaneus at the site of tendon rupture seen as an echogenic structure casting posterior shadowing (long arrow). Transverse image (b) confirms the abnormality seen on longitudinal scanning. Plain radiograph for the ankle in lateral view (c) shows the bone fragments at the site of the distal part of the Achilles tendon (arrow). (d-f) Acute complete rupture of the distal-third of the Achilles tendon. Intraoperative photographs taken before surgical repair (d, e) show complete rupture of the tendon, and the proximal end of the tendon held by Ethibond sutures (e) (arrow). Intraoperative photograph taken after surgical repair of the tendon with end-to-end suture (f).|
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|Figure 2: Acute complete rupture of the Achilles tendon. Longitudinal ultrasonography image (a) shows break of the tendon and paratendon (long arrows) with hypoechoic 'mass-like' structure within the substance of the tendon suggested to be hematoma (short arrows). Intraoperative photograph taken at the time of surgical repair (b) shows complete rupture of the tendon and the cut ends of the tendon held by forceps (arrows). Intraoperative photograph taken after surgical repair with end-to-end suture of the tendon (c).|
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The sonographic and operative findings were correlated in all cases to assess the capability of US to differentiate partial from complete rupture of the Achilles tendon.
This study was conducted in accordance with the Declaration of Helsinki. This study was conducted with approval from the Institutional Ethics Committee. Written informed consent was obtained from all participants.
| Results|| |
The right tendon was injured in 70.2% (33/47) and the left tendon in 29.8% (14/47) of cases. The middle-third of the tendon (tendon substance) was the site of rupture in 66% (31/47) [Figure 3] and the distal-third (insertional) in 34% (16/47) [Figure 1] and [Figure 4]. No tendon ruptures were found at the musculotendinous junction.
|Figure 3: Example of a false-positive case. Acute complete rupture of the middle-third of the Achilles tendon thought to be partial rupture on ultrasonography (US). Longitudinal US image (a) shows partial break of an enlarged tendon (long arrow), but the paratendon was intact and a linear hypoechoic area is seen coursing through the tendon in a longitudinal manner suggestive of an intrasubstance tear, which in turn suggests partial rupture of the tendon (short arrows). On intraoperative photograph (b), this area was found to represent torn and retracted tendon fibers (short arrows) and the tendon was completely ruptured. The proximal end of the torn tendon is held by forceps (long arrow).|
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|Figure 4: Acute complete rupture of the Achilles tendon just above its insertion. Longitudinal ultrasonography image (a) shows nonvisualization of the tendon with a vague hypoechoic 'mass-like' structure replacing the distal part of the tendon suggested to be hematoma (arrows). Intraoperative photograph (b) shows complete rupture of the tendon just above its insertion (short arrows) and the proximal torn tendon held by the surgeon's hands (long arrows)|
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Surgery confirmed clinical and US diagnosis of Achilles tendon rupture in all 47 operatively treated tendons (accuracy = 100%). Surgery confirmed complete rupture in all 29 tendons thought to be completely ruptured on US (accuracy = 100%) [Figure 1] [Figure 2] and [Figure 4]) and confirmed partial rupture in 15 of the 18 tendons thought to be partially ruptured on US (accuracy = 83.3%) [Figure 5] and [Figure 6]. The remaining three lesions were found to be complete [Figure 3] and [Table 1].
|Figure 5: Acute partial tear of the Achilles tendon just above the insertion of the tendon on the calcaneus (calc.). Longitudinal ultrasonography (US) image (a) shows a thin linear hypoechoic area within the central substance of the tendon suggestive of a partial tear (short arrows). The tendon and paratendon were intact (long arrow). Longitudinal US image in the contralateral asymptomatic tendon in the same patient for comparison (b) shows uniformity of the echogenic tendon fibril architecture. Intraoperative photograph (c) shows the partial longitudinal tear within the tendon (small arrows)|
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|Figure 6: Acute partial rupture of the Achilles tendon. Longitudinal ultrasonography image (a) shows an enlarged tendon with a central focal area of hypoechogenicity within the substance of the tendon suggestive of a hematoma (small arrows). The posterior tendon fibers and paratendon were intact (long arrows), suggesting partial rupture. Intraoperative photograph (b) shows edema and thickening of the tendon possibly due to intrasubstance hematoma at the site of rupture (arrows) with most tendon fibers intact consistent with partial tendon rupture|
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Regarding US findings of complete or partial rupture of the Achilles tendon, break of the tendon and paratendon, nonvisualization of the tendon, and the presence of gap (hematoma) or bone fragments within the tendon were found to be characteristic findings for complete tendon rupture. All 26 cases with break of the tendon and paratendon [Figure 1] and [Figure 2], all three cases with a nonvisualized tendon [Figure 4], and all seven cases with bone fragments within the tendon [Figure 1] on US were found to have complete ruptures at surgery. Tendon gap (hematoma) was seen in 81.2% (26/32) of cases with complete rupture [Figure 1] [Figure 2], and [Figure 4] versus 26.6% (4/15) of cases with partial rupture [Figure 6] (P = 0.06).
By contrast, break of the tendon with an intact paratendon, intact tendon with internal hypoechogenicity (tear), and tendon thickening were found to be characteristic findings for partial tendon rupture. All seven cases with linear hypoechogenicity (tear) within the substance of an intact tendon on US were found to have partial rupture at surgery [Figure 5]. Break of the tendon with an intact paratendon was seen on US in 11 cases. All were thought to have partial rupture but operative findings correlated with US diagnosis in eight cases and other three cases showed retracted tendons with accompanying tendon tear consistent with complete rupture [Figure 3]. As a result, break of the tendon with intact paratendon was seen in 53.4% (8/15) of cases with partial rupture versus 9.3% (3/32) of cases with complete rupture (P<0.05). Tendon thickening was seen in 73.3% (11/15) of cases with partial rupture [Figure 6] versus 25% (8/32) of cases with complete rupture (P = 0.05). Comparison of US findings of complete and partial rupture of Achilles tendon is illustrated in [Table 2].
|Table 2 Comparison of ultrasonography findings of complete and partial rupture of Achilles tendons |
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| Discussion|| |
The choice of treatment regimen of an acute Achilles tendon rupture is still based on the preference of the surgeon and the patient as there is no agreed-upon protocol  . Operative treatment has been the method of choice in the last two decades for athletes and young people and for patients who have a rupture for which treatment has been delayed  . Acute ruptures in nonathletes and in patients with partial ruptures may be treated nonoperatively , . Therefore, it is important to define the type of rupture preoperatively. Although US has been used to examine the status of the ruptured Achilles tendon ,,, , there is limited information available about the capability of US to verify the type of rupture. This topic has not been addressed separately in previous studies.
Margeti et al.  have assessed the value of US in the diagnosis of Achilles tendon rupture by comparing preoperative US findings and operative findings in 88 patients, and the type of rupture was included as one of these findings and not assessed as the original aim of this study. The authors found that US was a reliable method for identification of complete rupture but it was less reliable in the case of a partial rupture as surgery confirmed complete ruptures in all 78 tendons thought to be completely ruptured on US and confirmed partial ruptures in two of the 10 tendons thought to be partially ruptured on US. The remaining eight lesions were found to be complete.
Paavola et al.  have found that US was highly reliable for verifying a complete Achilles tendon rupture; only one false-negative US examination was found in the 26 surgically verified cases. However, US seemed to be inadequate for differentiating partial tendon rupture from a focal tendon degeneration not from complete rupture.
Results of our study agreed with those of Margeti et al.  regarding complete rupture of the Achilles tendon as surgery confirmed complete rupture in all 29 tendons that were thought to be completely ruptured on US. However, contrary to the results of Margeti et al.  , surgery confirmed partial rupture in 15 of the 18 US examined partial lesions and only three lesions were complete. Therefore, US was capable of identifying both complete and partial rupture of the Achilles tendon.
We suggested partial rupture on US in all three patients with a false-positive diagnosis of partial rupture because the paratendon was intact despite break of the tendon, but surgery showed that the tendons were retracted with accompanying tendon tear consistent with complete rupture. By contrast, in the eight patients with a false-positive diagnosis of partial rupture in the study by Margeti et al.  , all tendon fibers were ruptured but some of them had impacted, which gave them an intact appearance on US examination.
The sonographic changes in the Achilles tendon rupture and the characteristic US findings of complete and partial ruptures in our study were similar to those changes that have been mentioned in the literature ,,,, . The break of the tendon and paratendon or nonvisualized tendon associated with the presence of hematoma or bone fragments within the tendon on US were characteristic findings for complete rupture, whereas the presence of linear hypoechogenicity (tear) within the substance of an intact tendon or break of the tendon with an intact paratendon and associated tendon thickening were characteristic findings for partial rupture. However, the presence of bone fragments within the substance of the tendon at the site of rupture was an additional finding for complete rupture. Bone fragments avulsed from the posterior aspect of the calcaneus were detected in seven cases. All had rupture at the distal-third of the tendon just above its insertion site.
Previous researchers have found that dynamic ultrasound can assess the effect of knee and ankle position on the Achilles tendon apposition following acute rupture. Maximum ankle equinus alone significantly reduces the gap distance after acute Achilles tendon rupture. Increasing knee flexion further reduces the gap distance by small increments. These findings are clinically relevant as they may play an important role in the closed treatment of acute rupture of the Achilles tendon and in deciding the line of treatment, whether conservative or surgical  .
We tried to overcome some limitations that have been mentioned in previous studies. First, the final diagnosis was based only on surgical findings as the gold standard to obtain more reliable results. Second, surgery was performed no later than 12 h after US examination to obviate the possibility of rerupture between US examination and surgery. Finally, we evaluated the contralateral asymptomatic tendon by US in all cases to provide a comparison of normal.
The limitations of our study were the small number of cases and that US, as an imaging modality, is limited in that it is operator dependent.
We conclude that US may be considered a reliable imaging modality in detecting Achilles tendon ruptures and it may help to distinguish partial from complete ruptures, allowing for more appropriate patient management.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
[Table 1], [Table 2]