Biological and Clinical Sciences Research Journal
ISSN:
2708-2261
www.bcsrj.com
DOI:
https://doi.org/10.47264/bcsrj0101040
Biol. Clin. Sci. Res. J., Volume, 2020: e040
Original Research
DIAGNOSTIC ACCURACY
OF ULTRASOUND IN DETECTING MENISCAL TEARS TAKING MAGNETIC RESONANCE IMAGING AS
GOLD STANDARD
OMER MA1*, MALIK SS2, MALIK AA3, ANJUM MN2, RIAZ AZ4, ALI R5
1Department of Diagnostic Radiology, The
University of Lahore, Lahore, Pakistan
2Radiology Research Section, The
University of Lahore, Lahore, Pakistan
3Consultant Interventional Radiologist, Doctors Hospital and
Medical Center, Lahore, Pakistan
4House Officer Radiology, Services Hospital Lahore, Lahore,
Pakistan
5Consultant Radiologist DHQ Hospital Sheikupura,
Pakistan
Corresponding
& First Author email: dr.arslan14@gmail.com
Abstract
Meniscal tears are mostly seen worldwide. Multiple
imaging modalities are currently used to evaluate pathologic conditions of the
knee. MRI can be referred as the non-invasive gold standard investigation to
help establishing diagnosis of meniscal tears, but it
economically unaffordable to most of patients and needs long examination times.
Ultrasound is a possible alternative to MRI. It is simple, convenient and an
inexpensive and non-invasive method. The use of ultrasound in identifying meniscal tears has been proposed, but its diagnostic
accuracy remains controversial. The objective of the research is to
define the diagnostic accurateness of ultrasound scan in detecting meniscal tears taking magnetic resonance imaging as gold
standard. It was a diagnostic
cross-sectional study in which 78 patients visiting Department of Diagnostic Radiology, Doctors Hospital, Lahore were included. Convenient sampling technique was used. Written informed consent
was taken from all the patients. Patients
were investigated with the help of ultrasound and results were noted on the
designed proforma, subsequently the results were
compared to the MRI scan of the knee joint. Data was entered and
statistically analyzed using SPSS 21.0. Frequency
tables were generated for all variables. For quantitative data like age mean
and standard deviation were calculated and for qualitative data like sex and meniscal tears percentages were calculated. Sensitivity,
Specificity, Positive Predictive Value, Negative Predictive Value was given.
Bar and pie charts were used to present categorical data. Kappa analysis was
utilized. The mean age of the patients was 38.18+12.818
years, 82.1% were males and 47.4% had sports trauma. Out of 48 medial meniscus
tear on USG, 38(48.7%) were true positive and 10(12.8%) were false positive on
MRI. Out of 10 lateral meniscus tear on USG, 9(11.5%) were true positive and
1(1.3%) was false positive on MRI. The sensitivity, specificity, PPV, NPV and
diagnostic accuracy of ultrasound for medial meniscus tears were 95.00%,
73.68%, 79.16%, 93.33% and 84.61% while for lateral meniscus tears were 75.00%,
98.48%, 90.00%, 95.58% and 94.87%, respectively. Study concluded that
ultrasound has good diagnostic accuracy when compared with magnetic resonance
imaging in detecting meniscal
tears.
Keywords:
Ultrasound, meniscal
tears, magnetic resonance imaging, diagnosis, sensitivity
Introduction
The knee joint is one of the most vulnerable
joint of the body (Sharma and Grewal,
2020). The ligaments establish the chief supportive structure
of the knee joint. Owing to the fact that the bony structures of knee joint is
restricted, the other structure including ligaments, tendons, menisci and
cartilages makes the main role to stabilize the knee joint and prevent it from
injuries (Sally and Ali, 2019). Menisci are vital for the functional well-being of the
knee. An intact meniscus is crucial for maintaining normal knee function, such
as shock absorption, joint lubrication and load transmission across the knee
joint. It increases contact area and hence decreases contact stress on the articular cartilage (Stewart, 2010). The most common causes of knee pain and disability
are tears in medial or lateral menisci (Attya, 2015). Meniscal tears are mostly
seen worldwide (Snoeker et al., 2013) and are common in both athletes and non-athletes. They
can cause knee pain and disability as well as the onset and progression of knee
osteoarthritis (Akatsu et al., 2015). The prevalence of asymptomatic tears, which
typically are horizontal tears, increases with age (Nguyen et al., 2014). Meniscal tears are the most
widely recognized pathology of the knee with a mean yearly occurrence of 66 for
every 100000 (Mostafa et al., 2019). Almost two third of patients of older
age (more 65 years) experience progressive meniscal
tears. Situated in between the tibial and
femoral bones, two semilunar segments structure of
knee joint called the menisci (Mahdy et al., 2018). The medial meniscus is C-shaped structure measuring
about 3.5 cm longitudinally beginning anteriorly towards
posteriorly (Acebes et al., 2013). It is unequal with a significantly broader posterior
end than frontal end. The lateral meniscus is almost round shape making a
circle covering most of the area of tibial upper
surface (Najafi et al., 2006; Razek et al.,
2009). The medial meniscus by its center portion establishes
secure links with fibers of the collateral ligaments (through its deep medial
part) (Nogueira-Barbosa et al., 2015).
Meniscal tears has 6 subtypes: 1. Longitudinal tears; makes
bucket shape when dislocated, 2. Radial tears, 3. oblique flap (Parrot-beak)
tears, 4. Horizontal tears, 5. Root tears, 6. A
mixture of all the above subtypes called the Complex tears. The classification
of meniscal tears provides a description of pathoanatomy. Warner and Harner
classified meniscal tears on the basis of their
location in three zones of vascularity – red-red
(fully within the vascular area), red-white (at the border of the vascular
area), and white (within the avascular area). They
use this classification to determine the potential for healing after repair.
Tears in red-red and red-white zones have good potential for healing after
repair. Successful repair and healing relieves meniscal
symptoms and allows the patient to return to full function. Multiple imaging
modalities are currently used to evaluate pathologic conditions of the knee (Murmu et al., 2017). Clinical diagnosis of meniscal
tears can be difficult even for the most experienced orthopedic surgeons, which
is most often diagnosed based on history, clinical symptoms, magnetic resonance
imaging (MRI), or arthroscopy. Arthroscopy is main diagnostic standard test,
but its negative aspects include that it is very costly, invasive procedure and
necessitate hospital stay for surgery (Dong et al., 2018).
Magnetic resonance imaging has attained
acceptance as an analytical means for the musculoskeletal system since its
introduction in the 1980s (Wang et al., 2019). Magnetic resonance imaging is not invasive and does not
require exposure to ionizing radiation (Alizadeh et al., 2013). Since then, due to the better signal-to-noise ratio,
higher resolution, reduced number of artifacts, shorter imaging time and better
accuracy, MRI has clearly become the main imaging tool in knee joint pathology
studies (Phelan et al., 2016; Wang et al.,
2019). MRI not only depicts osseous lesions, but provides
information on the cartilages, menisci, ligaments and surrounding soft-tissues.
On MRI meniscal tears are characterized by linear,
complex, or diffuse increased signal intensity within the meniscus which
communicates with an articular surface (Arif et al., 2013). It gives a high sensitivity of 93% for medial meniscus
and 79% for lateral meniscus and also a high specificity of 88% for medial
meniscus and 96% for lateral meniscus for diagnosing the meniscal
tears (Choi et al., 2010). MRI can be taken as the non-invasive “diagnostic gold
standard” for meniscal tears, its high cost and the
long examination times are the negative points (De Smet et al., 2009). Diagnostic ultrasound of the knee can identify
abnormalities in the menisci. It is simple, convenient and an inexpensive and
non-invasive method (Oei et al., 2003). Ultrasound can accurately determine the location and
presence of tear. It also can differentiate complete tears from partial tears,
an important distinction because the former requires surgery. Partial tears are
seen as a cleft or anechoic region with the tendon with interruption of its
normal echogenic fibrillar
pattern. Complete tears are seen as complete disruption of the tendon with
separated ends (Lee and Chow, 2007). The use of ultrasound (US) as a clinical investigative
tool started in 1950’s. US application in imaging remained underutilized until
1980’s. It is a noninvasive, freely available, well-accepted
by patients, affordable and dynamic evaluation in real time. Recent advances in
US system instrumentation and transducer technology allowed better demonstration
of musculoskeletal diseases. The most known clinical application is the ability
to obtain a clear anatomical overview of the superficial structures around the
bones. Soft tissue pathology of the knee represented one of the common uses
since the nineties of the last century (Yousif et al., 2014). Ultrasound is a possible alternative to MRI
and can be performed rapidly, is less costly, and can be used to evaluate
muscles and tendons. Although the depth of penetration of ultrasound is
limited, recent developments in ultrasound have led to greater spatial
resolution as well as finer imaging detail than are possible with standard clinical
musculoskeletal MRI; therefore, its usefulness for diagnosing meniscal disease seems promising. The use of ultrasound for
identifying meniscal tears has been proposed, but its
diagnostic accuracy remains controversial (Dai et al., 2015). Problems with previous studies of ultrasound include a
failure to address the resolution of the machine. Therefore, the current
research aims to evaluate the diagnostic correctness of ultrasound scanning for
detecting meniscal tears taking Magnetic Resonance
Imaging as Gold Standard.
Material and methods
Study design
Diagnostic cross-sectional
Study setting
Department of Diagnostic Radiology, Doctors
Hospital, Lahore
Study duration
9 months.
Sample size
78 patients according to following formula:
Population size (for finite population correction
factor or fpc)(N): 1000000
Hypothesized % frequency of outcome factor in
population (p): 86.4%+/-5
Confidence limits % of 100 (absolute +/- %)(d): 5%
Design effects (for cluster surveys-DEFF): 1
Equation
Sample Size n= [(DEFF×Np(1-p)]/[(d2/Z21-a/2×
(N-1)+p×(1-p)]
Sampling
technique
Convenient sampling
Sample
selection
Inclusion
Criteria
Patients between the age of
15 to 60 years of both genders with knee pain & positive in at minimum any
of the following bedside examination:
·
Joint Line Tenderness
·
McMurray Test
·
Apley Grind Test
Exclusion
Criteria
·
Unfit for MRI Investigation.
·
History of prior knee surgery.
·
Unwilling to participate.
Instruments/modality
Canon/Toshiba
Aplio 500 Platinum with Wide-ranging Group In lines
transducer with rate of recurrence of 7-18 Mhz.
Ethical considerations
·
Written informed consent was taken from all the patients.
·
All information and collected data was kept confidential by
saving data in my personal laptop and hard copies form data were in locker.
·
Contributors stayed unnamed during the course of the
research.
·
It was brought to the knowledge of the participants; they
will have no difficulties or risk from the procedures of the study.
·
They were similarly acknowledged that they will be free to
remove themselves at any time throughout the course of the study.
·
Printed record was stored in the lockers and soft copy was
password protected in the laptop.
Data collection
procedure
A Performa was planned by researcher and decided
after pre-testing. Those patients who visited Doctors’ Hospital & Medical
Center, Lahore were included and
investigated with the help of ultrasound and results were noted on the designed
Performa, subsequently the results were compared to the MRI scan of the knee
joint.
Technique
and equipment: The ultrasonography examination
was done with help of Canon/Toshiba Aplio 500
Platinum with Wide-ranging Group In lines transducer with rate of recurrence of
7-18 Mhz.
Patients
positioning: each participant was inspected in supine laying position
with knee joint flexed (at 20°-30°) for evaluation of anterior side of the
knee, while the posterior side was inspected in prone situation with the knee
not flexed (i.e. straight) and the cruciate ligament
flexed (at 60°-70°).
Medial
collateral ligament and medial meniscus: The leg was turned externally
with flexion slightly (at 20°-30°) for the inspection of the medial side of the
knee joint. Heavy part (which constitute hyperechoic fibrillar outer layer) and thinner part (which constitute
the deeper layer) are the two components which make the medial collateral
ligament. The hyperechoic wedge structure that lies
between the femur and tibia is refered as the medial
meniscus.
Lateral
collateral ligament and lateral meniscus: the leg was turned internally
with slight knee flexion (at 20°-30°) for the lateral side inspection of the
knee joint. Also the examination of lateral collateral ligament and the
anterior horn of lateral ligament are possible at this position.
Data
analysis
Data was entered & analyzed using SPSS
(Statistical Package for Social Sciences) version 22.0. Frequency tables were
generated for all variables. For quantitative data like age and, mean and
standard deviation were calculated and for qualitative data like sex and meniscal tears percentages were calculated. Sensitivity,
Specificity, Positive Predictive Value, Negative Predictive Value was given.
Bar and pie charts were used to present categorical data. Kappa analysis was
utilized.
Results
Table 1. Frequency distribution of patients according to age and
gender
Age |
Frequency |
Percentage (%) |
Upto 30 years |
26 |
33.3 |
31-40
years |
19 |
24.3 |
41-50
years |
17 |
22.0 |
Above
50 years |
16 |
20.4 |
Total
|
78 |
100.0 |
Mean+SD |
38.18+12.818 |
|
Sex |
Frequency |
Percentage (%) |
Male |
64 |
82.1 |
Female |
14 |
17.9 |
Total
|
78 |
100.0 |
Table
1 describes that among 78 patients, 26 (33.3%) were upto
30 years of age, 19 (24.3%) were 31-40 years of age and 17 (22.0%) were 41-50
years of age while 16 (20.4%) cases were more than 50 years of age. The mean
age of the individuals was 38.18+12.818 years. Table 1 depicts that
among 78 patients, 64 (82.1%) were males and only 14 (17.9%) were females.
Table 2. Occurrence distribution of patients depending on mode of
damages
Mode of
Injury |
Frequency |
Percentage (%) |
Road
Accident |
5 |
6.4 |
Senile
Changes |
2 |
2.6 |
Sports
Trauma |
37 |
47.4 |
Control
as per MRI |
34 |
43.6 |
Total |
78 |
100.0 |
Knee side |
Frequency |
Percentage (%) |
Right
|
58 |
74.4 |
Left
|
16 |
20.5 |
Both |
4 |
5.1 |
Total
|
78 |
100.0 |
Medial
meniscus tears on USG |
Frequency |
Percentage (%) |
Anterior
Zone Tear |
9 |
11.5 |
Middle
Zone Tear |
6 |
7.7 |
Posterior
Zone Tear |
33 |
42.3 |
No
Tear |
30 |
38.5 |
Total
|
78 |
100.0 |
Lateral
meniscus tears on USG |
Frequency |
Percentage (%) |
Anterior
Zone Tear |
0 |
0.0 |
Middle
Zone Tear |
3 |
3.8 |
Posterior
Zone Tear |
7 |
9.0 |
Normal |
68 |
87.2 |
Total |
78 |
100.0 |
Above
table 2 demonstrates the mode of injury among patients and found that 5 (6.4%)
patients had road accident, 2 (2.6%) senile changes and majority 37 (47.4%) had
sports trauma while 34 (43.6%) were control as per MRI. Table 2 shows that out
of 78 patients, right knee of 58 (74.4%) patients was examined and left knee of
16 (20.5%) patients was examined while both knees of 4 (5.1%) patients were
examined. Table 2 exhibits that according to USG findings, 9 (11.5%) patients
had medial meniscus tears in anterior zone, 6 (7.7%) patients in middle zone,
33 (42.3%) in posterior zone and 30 (38.5%) patients had no tear. Table 2 indicates
that according to USG findings, none of the patients had lateral meniscus tears
in anterior zone, 3 (3.8%) patients had in middle zone and 7 (9.0%) in
posterior zone while majority of the patients had no tear 68 (87.2%). Table 3 asserts
that according to MRI findings, 8 (10.3%) patients had medial meniscus tears in
anterior zone, 3 (3.8%) patients in middle zone, 29 (37.2%) in posterior zone
and 38 (48.7%) patients had no tear. Table 3 highlights that according to MRI
findings, none of the patients had lateral meniscus tears in anterior zone, 3
(3.8%) patients had in middle zone and 9 (11.5%) in posterior zone while
majority of the patients had no tear 66 (84.7%).
Table 3. Frequency distribution of patients according to medial meniscus tears on MRI
Medial
Meniscus tears on MRI |
Frequency |
Percentage (%) |
Anterior
Zone Tear |
8 |
10.3 |
Middle
Zone Tear |
3 |
3.8 |
Posterior
Zone Tear |
29 |
37.2 |
Normal |
38 |
48.7 |
Total
|
78 |
100.0 |
Lateral
meniscus tears on MRI |
Frequency |
Percentage (%) |
Anterior
Zone Tear |
0 |
0.0 |
Middle
Zone Tear |
3 |
3.8 |
Posterior
Zone Tear |
9 |
11.5 |
Normal |
66 |
84.7 |
Total
|
78 |
100.0 |
Table 4 reveals that out of 58 meniscus tears on USG, 48 were medial tears and 10 were lateral tears. Out of 48 medial tears, 9 (11.5%) were found in anterior zone, 6 (7.7%) in middle zone and 33 (42.3%) in posterior zone. Likewise out of 10 lateral tears, 3 (3.8%) were found in middle zone and 7 (9.0%) in posterior zone. Table 5 indicates that out of 52 meniscus tears on MRI, 40 were medial tears and 12 were lateral tears. Out of 40 medial tears, 8 (10.3%) were found in anterior zone, 3 (3.8%) in middle zone and 29 (37.2%) in posterior zone. Likewise out of 12 lateral tears, 3 (3.8%) were found in middle zone and 9 (11.5%) in posterior zone. Table 6 depicts that out of 48 medial meniscus tear on USG, 38 (48.7%) were true positive and 10 (12.8%) were false positive on MRI. Out of 30 medial meniscus without tear, 2(2.6%) were false negative and 28 (35.9%) were true negative on MRI. The Kappa value was 0.000. Table 7 demonstrates that out of 10 lateral meniscus tear on USG, 9 (11.5%) were true positive and 1 (1.3%) was false positive on MRI. Out of 68 lateral meniscus without tear, 3 (3.8%) were false negative and 65 (83.4%) were true negative on MRI. The Kappa value was 0.000. Table 8 depicts that sensitivity, specificity, PPV, NPV and diagnostic accuracy of ultrasound for medial meniscus tears were 95.00%, 73.68%, 79.16%, 93.33% and 84.61% while for lateral meniscus tears were 75.00%, 98.48%, 90.00%, 95.58% and 94.87%, respectively.
Table 4. Breakdown of meniscus tears on USG
|
Anterior Zone |
Middle Zone |
Posterior
Zone |
Medial
meniscus |
9 (11.5%) |
6 (7.7%) |
33 (42.3%) |
Lateral
meniscus |
0 (0.0%) |
3 (3.8%) |
7 (9.0%) |
Total
Meniscus Tear: 58, Medial Tear 48, Lateral Tear: 10
Table 5. Breakdown of meniscus tears on MRI
|
Anterior Zone |
Middle Zone |
Posterior
Zone |
Medial
meniscus |
8 (10.3%) |
3 (3.8%) |
29 (37.2%) |
Lateral
meniscus |
0 (0.0%) |
3 (3.8%) |
9 (11.5%) |
Total
Meniscus Tear: 52, Medial Tear 40, Lateral Tear: 12
Table 6. Diagnosis of medial meniscus tears by ultrasound and MRI
Ultrasound
findings |
MRI findings |
Total |
|
Meniscus with
tear |
Meniscus
without tear |
||
Meniscus
with tear |
38 (48.7%) |
10 (12.8%) |
48 (61.5%) |
Meniscus
without tear |
2 (2.6%) |
28 (35.9%) |
30 (38.5%) |
Total
|
40 (51.3%) |
38 (48.7%) |
78 (100.0%) |
Kappa
= 0.000
Table 7. Diagnosis
of lateral meniscus tears by
ultrasound and MRI
Ultrasound
findings |
MRI findings |
Total |
|
Meniscus with
tear |
Meniscus
without tear |
||
Meniscus
with tear |
9 (11.5%) |
1 (1.3%) |
10 (12.8%) |
Meniscus
without tear |
3 (3.8%) |
65 (83.4%) |
68 (87.2%) |
Total
|
12 (15.3%) |
66 (84.7%) |
78 (100.0%) |
Kappa
= 0.000
Table 8. Diagnostic accurateness of ultrasound in detecting meniscus
tears
|
Medial meniscus |
Lateral meniscus |
Sensitivity
|
95.00% |
75.00% |
Specificity
|
73.68% |
98.48% |
Positive
predictive value (PPV) |
79.16% |
90.00% |
Negative
predictive value (NPV) |
93.33% |
95.58% |
Diagnostic
accuracy (DA) |
84.61% |
94.87% |
DISCUSSION
Menisci
are significant for the functional well being of the knee. An undamaged
meniscus is important for maintaining the normal function of knee namely joint
lubrication, shock absorption, and weight transmission across the knee joint.
For knee pain and disability, the most frequent reasons are tears in lateral or
medial menisci. The meniscal tears can lead to knee
pain, disability and onset & knee osteoarthritis progression. Several
imaging modalities are presently utilized to assess pathologic conditions of
knee. Clinical diagnosis of meniscal tears can be
difficult even for the most experienced orthopedic surgeons, which is most
often diagnosed based on history, clinical symptoms, magnetic resonance imaging
or arthroscopy. MRI not only depicts osseous lesions, but provides information
on the cartilages, menisci, ligaments and surrounding soft-tissues. MRI can be
considered as the non-invasive “gold standard” for the diagnosis of meniscal tears, but it is expensive and needs long
examination times. Diagnostic ultrasound of the knee can identify abnormalities
in the menisci. Ultrasound can accurately determine the location and presence
of tear. It is simple, noninvasive, freely available, well-accepted by
patients, inexpensive and dynamic evaluation in real time. Therefore, current
study is carried out to assess the diagnostic accuracy of ultrasound scanning
in detecting meniscal tears taking magnetic resonance
imaging as gold standard. To acquire adequate outcomes, a group of 78 patients
was included in the study and found that only 33.3% patients were up to 30
years old and majority (66.7%) was more than 50 years old while the mean age of
the patients was 38.18+12.818 years. But a study carried out by Shetty (2013) reported that majority of the patients
(58.4%) were upto 30 years old and 41.6% were more
than 30 years old while the mean age of the patients was 30.66+10.58
years. The findings of our study are comparable with a recent study undertaken
by Mostafa and his coworkers (2019) who asserted that
mean age of the patients was 37.65 ± 10.24. Another study performed by Razek and his associates indicated that mean age of the
patients was 41.2 ± 11.5 years (Razek et al.,
2009). It has been
confirmed that mean age of the patients was 30.42±5.91 (Shetty, 2013). As far as gender of the
patients is concerned, study revealed that disease was more prevalent among
male than female patients. It was found that significant majority (82.1%) of
the patients were male and only 17.9% were female patients. Several studies
carried out in different parts of the worlds also showed similar situation. In
a study Yousif et
al., (2014) reported that most of the patients (83.0%) were male and only
17.0% were female patients. Similarly, Sharma and Grewal
(2020) highlighted in their study that 65.0% patients were male and 35.0% were
female. Another study conducted by Mostafa et al., (2019) elucidated that 62.0%
were male and 38.0% were female patients. When the mode of injury
was assessed among patients, study disclosed that most of the patients (47.4%)
had sports trauma, followed by road accident (6.4%) and senile changes (2.6%)
while 43.6% were control as per MRI. The results of a similar study undertaken
by Murmu and his fellows reported that majority of
the patients (70.59%) had sports trauma, followed by domestic falls (11.76%)
and road accident (5.89%) while 11.76% cases had miscellaneous causes (Murmu et al.,
2017).
Study
revealed that among 74.4% patients, right knee was affected and in 20.5%
patients, left knee was affected while in 5.1% patients both knees were
affected. While a study done by Razek and his
associates indicated that among 67.0% patients; left knee was affected while
among 33% patients, right knee was affected (Razek et al.,
2009). Likewise, a
study carried out by Arif and his comrades (2013)
also confirmed that among majority (72.0%) of patients; left knee was affected
while among 28.0% patients, right knee was affected. But a study done by Murmu and his fellows showed almost comparable results that
among 62.75% patients, right knee was affected and in 37.25% patients, left
knee was affected (Murmu et al.,
2017). It was found during study that according to
USG findings, medial meniscus tears (anterior, middle and posterior zone tears)
were detected in 61.5% patients and 38.5% patients had no tear. But lateral
meniscus tears (anterior, middle and posterior zone tears) were detected in
only 12.8% patients and majority (87.2%) of the patients had no tear. In
another similar study Yaseen and Gorial
asserted that as per ultrasound results, meniscal
tear were detected among 70% patients while 30.0% patients had no tear (Yaseen and Gorial, 2019). Study further disclosed as per
MRI findings, medial meniscus tears (anterior, middle and posterior zone tears)
were detected among 51.3% patients while 48.7% patients had no tear. But
lateral meniscus tears (middle and posterior zone tears) were detected in only
15.3% patients and major proportion (84.7%) of the patients had no tear. While
study carried out by Yaseen and Gorial
(2019) reported that according to MRI findings, medial meniscal
tears were identified among 88% patients while 12% patients had no tear (Yaseen and Gorial, 2019). The outcomes of study
indicated that according to USG, 48 were medial meniscus tears and 10 were
lateral meniscus tears. Out of 48 medial meniscus tears, 9 were found in
anterior zone, 6 in middle zone and 33 in posterior zone. Likewise out of 10
lateral tears, 3 were found in middle zone and 7 in posterior zone. But
according to MRI findings, 40 were medial meniscus tears and 12 were lateral
meniscus tears. Out of 40 medial meniscus tears, 8 were found in anterior zone,
3 in middle zone and 29 in posterior zone. Similarly out of 12 lateral tears, 3
were found in middle zone and 9 in posterior zone. A study carried out by Gadgil and his partners (2018) indicated that most of the
patients had medial meniscal tear (123), followed by
lateral meniscal tear (25) and both medial &
lateral meniscu tear (12) (Gadgil et al.,
2018).
The
results of our study further indicated that out of 48 medial meniscus tear on
USG, 38 were true positive and 10 were false positive on MRI. Out of 30 medial meniscus without tear on USG, 2 were false negative and 28
were true negative on MRI. Similarly out
of 10 lateral meniscus tear on USG, 9 were true positive and 1 was false
positive on MRI. Out of 68 lateral meniscus without
tear on USG, 3 were false negative and 65 were true negative on MRI. A study indicated
that out of 42 meniscus tear on USG, 41 were true positive and 1 was false
positive on MRI. Out of 17 meniscus without tear on USG, 7 were false negative
and 10 were true negative on MRI (Crawford et al.,
2007). The findings
of another study undertaken by Mostafa and his
coworkers reported that out of 26 meniscus tear on USG, 16 were true positive
and 10 were false positive on MRI. Out of 36 meniscus without tear on USG, 2
were false negative and 32 were true negative on MRI (Mostafa et al.,
2019).
It
was very encouraging that sensitivity, specificity, PPV, NPV and diagnostic
accuracy of ultrasound for medial meniscus tears were 95.00%, 73.68%, 79.16%,
93.33% and 84.61% while for lateral meniscus tears were 75.00%, 98.48%, 90.00%,
95.58% and 94.87%, correspondingly. The findings of our research demonstrated
more useful results than the finding of previous researchers where the
specificity, sensitivity, PPV, NPV and diagnostic accuracy of ultrasound for
medial meniscus tears were 80.7%, 62.5%,
75.0%, 70.0% and 72.0% while for lateral meniscus tears were 23.0%,
89.1%, 42.8%, 76.7% and 72.0%, respectively (Bien
et al., 2018; Cimino et al., 2010; Micheo et al., 2010). It has been reported
that assuming the magnetic resonance imaging as gold standard, the sensitivity,
specificity, PPV, NPV and diagnostic accuracy of ultrasound were 85.4%, 90.9%,
97.6%, 58.8% and 86.4%, respectively (Crawford et al.,
2007). Another study performed by Alizadeh et al.,
(2013) highlighted that sensitivity, specificity, PPV, NPV and DA of ultrasound
in detecting meniscal tears were 100.0%, 88.9.0%,
96.5%, 100.0% and 97.3%, respectively.
Conclusion
Meniscal tears are most common public health problems worldwide
and can lead to knee pain, disability and knee osteoarthritis. Present study
assessed the diagnostic accuracy of ultrasound scanning in detecting meniscal tears taking magnetic resonance imaging as gold
standard. Study concluded that ultrasound has good diagnostic accuracy when
compared with magnetic resonance imaging in
detecting meniscal tears. It is comparatively simple
and inexpensive investigation and could be utilized in the clinical practice.
Further studies are need on large scale to assess the diagnostic accuracy of ultrasound scanning in detecting meniscal tears.
Conflict of interest
The
authors declared absence of any conflict of interest for manuscript
publication.
References
Stewart, T. (2010). Tribology of artificial joints. Orthopaedics and Trauma 24, 435-440.