Open Journal of Orthopedics, 2013, 3, 321-324
Published Online December 2013 (http://www.scirp.org/journal/ojo)
http://dx.doi.org/10.4236/ojo.2013.38059
Open Access OJO
321
Is Ultrasound Effective in Diagnosing Internal
Derangements of the Knee?
S. K. Venkatesh Gupta, Sugnanam Sirish Aditya
Department of Orthopaedics, Mamata Medical College/General Hospital, Khammam, India.
Received October 30th, 2013; revised November 29th, 2013; accepted December 15th, 2013
Copyright © 2013 S. K. Venkatesh Gupta, Sugnanam Sirish Aditya. This is an open access article distributed under the Creative
Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original
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ABSTRACT
Internal derangement of knee significan tly affects daily activities of patients and management of su ch cases with accu-
rate diagnosis and early treatment is of utmost importance. This study determines the benefits of arthroscopy directly
and also compares the sensitivity and specificity of ultrasound, MRI and arthroscopic findings in diagnosing internal
derangements of the knee. This is a prospective study of 50 cases that in cludes patients having knee pain and instability
of joint for more th an 6 weeks, symptoms of locking of knee joint or effusion and h aving no bony injury as con firmed
by X ray. Results were analysed and sensitivity and specificity were calculated. The present study supports that the
clinical diagnosis is of primary necessity, while ultrasound and MRI are additional diagnostic tools in diagnosing IDK.
Arthroscopy combines more accurate diagnosing tool and therapeutic modality, which is a more convenient, economical
and convincing technique to both surgeon and patient alike. Although ultrasound is less accurate than MRI, it is cost
effective and available at most of the peripheral centres. So it is better to do ultrasound rather than MRI for diagnosing
IDK in peripheral centres and refer to specialty clinics or tertiary centres for further diagnosis and treatment.
Keywords: Knee; Menisci; MRI; Ultrasound; ACL; PCL; Arthroscopy
1. Introduction
The modern high speed motor vehicular trauma and the
sporting life style have become obsessions in all age
groups, causing damage to bone and soft tissue elements
especially of knee and causing internal derangement in-
juries. They account for a large number of referred cases
to specialty clinics and referral centers not only from the
peripherals and general practitioners but also from other
major centres. As it comes in the way of daily activities
and significantly affects financial earning of the person
and family, it is important to deal such cases with accu-
rate diagnosis and early treatment [1-4].
Combined lesions are more difficult to diagnose. The
clinical examination and special tests to determine insta-
bility and internal derangement still stand as preliminary
and gold standard s, more reliable and cost ef fective ways
of diagnosing such knee problems. Literature reviews
show that clinical examination is not always accurate to
diagnose IDK [5,6]. Ultrasound and MRI are non inva-
sive tools in investigating internal derangements of knee,
but false and misleading results are equally reported in
the literature. The difficulty in diagnosing lesions of the
knee is that different lesions in the knee joint can pro-
duce similar findings. Arthroscopy has been considered
as the gold standard for the diagnosis of IDK, but is in-
vasive, expensive and requires day surgery admission.
Hence, this study is inten ded to determine the benefits of
arthroscopy directly and also to compare the sensitivity
and specificity of ultrasound , MRI and arthroscopic find-
ings in diagnosing internal derangements of the knee.
2. Methodology
This is a prospective study of 50 cases admitted to
Mamata General and Super Speciality Hospital between
May 2011 and Dec 2012 having knee joint problem like
pain and instability of knee joint for more than 6 weeks,
those with recent symptoms of locking of knee joint or
effusion and those with chronic knee pain having no

Is Ultrasound Effect iv e in Diagnosing Internal Derangements of the Knee? 322
bony injury confirmed by x ray were included. All pa-
tients were clinically examined and were evaluated with
x-ray, ultrasound, MRI scan and diagnostic arthroscopy.
Patients treated for tuberculosis of knee and septic arthri-
tis, chronic osteoarthrosis or ankylosis of knee and those
who underwent arthroscopy previously were excluded
from the study. A standard 7.5 MHz ultrasound probe
and 0,3 Tesla MRI scanner was used in this study.
2.1. Positioning during Ultrasound Examination
Ultrasound of the knee was performed with a using a
linear array 7.5 MHz probe. The patient was initially
placed supine with the knee extended. The anterior horns
were examined from the medial and lateral aspects re-
spectively. The knee was then flexed to 90 degrees and
the probe rotated laterally to ex amine the Anterior Cruci-
ate Ligament (ACL). This was a dynamic examination
with the knee being serially extended during the proce-
dure.
The patient was then turned prone and the posterior
horns were examined from the medial and lateral aspects
respectively. The Posterior Cruciate Ligament (PCL) was
then examined with the probe rotated medially.
2.2. Positioning of Patient during Arthroscopy
Arthroscopy of knee is done by hanging limb by side of
table with knee in 90˚ degrees of flexion and for full
range of motion at knee joint during procedure (Figure
1).
2.3. Portal Placement
In our complete study we used anteromedial and antero
lateral portals for diagnostic arthroscopy (Figure 1).
3. Results
The study had 50 patients of which 40 (80%) were males
and 10(20%) wer e f e males.
In our study patients are in between 18 to 50 years of
age.
More no of patients are in between 21 to 30 years of
age (Chart 1).
Mean age of the study group was 28.3 years with age
range between 19 - 43 years.
In our study of 50 patients there are different modes of
injury in which Sports injury (64%) was the most com-
monest cause of modality of injury followed by road
traffic accident (16%) (Chart 2).
All patients were clinically examined and were evalu-
ated with X-ray, ultrasound, MRI scan and diagnostic
arthroscopy.
X rays were done to rule out associated fractures.
In our study we screened four structures like lateral
Figure 1. Patient positioning and portal placement in ar-
throscopy.
25
20
10
0
15
556
NOOFCASES
22
17
18‐20 21‐30 31‐4041‐50
AgedistributionofStudyPopulation
Chart 1. Age distribution of study population.
0
20
40
60
80
sp orts
injury
RTAdomesticothers
0
20
40
60
80
Sports
injur y
RTAonthersdomestic
Chart 2. Graph deipicting mode of injury in patients with
Internal derangement of knee in our study.
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Is Ultrasound Effect iv e in Diagnosing Internal Derangements of the Knee?
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323
meniscus, medial meniscus, anterior cruciate ligament
and posterior cruciate ligament.
We compared results of ultrasound and MRI with di-
agnostic arthroscopy.
The results of 50 cases evaluated for internal de-
rangement of knee with MRI, Ultrasound and arthro-
scopy are tabulated in Table 1.
MRI had 74.1% sensitivity and 100% specificity in
diagnosing ACL injuries while ultrasound scan had
74.2% sensitivity and 100% specificity in our study
group. MRI had 96.1% sensitivity and 95.8% specificity
in diagnosing Medial mensical injuries while ultrasound
scan had 85.2% sensitivity and 86.1% specificity. MRI
had 85.7% sensitivity an d 100% sp ecificity in diagno sing
lateral meniscal injuries while ultrasound scan had 71 .4 %
sensitivity and 100% specificity. Our results show that
ultrasound scan is equally good in picking up internal
derangement of knee as compared to MRI scan (Table
2).
4. Discussion
Ultrasound diagnosis of orthopedic conditions has gath-
ered pace in recent years. It has become popular because
it is safe, quick, inexpensive and fairly reliable [7,8].
Ultrasound diagnosis of Internal derangement of knee
has been tried in various studies with variable results.
Most of these studies compare ultrasound with arthro-
scopy or arthrography [9-12]. Some of the cadaver and
clinical studies on the d iagnostic efficiency of ultrasound
in Internal derangement of knee report high yield rates
with sensitivity for menisci ranging from 76% to 100%
and specificity from 50% to 97% [8,9,12]. In other stud-
ies the sensitivity for menisci was as low as 30% to 40%
[8,11]. The use of 7.5 MHz probe for the visualization of
the menisci is well established and our experience was
the same (2). In our study the sensitivity and specificity
for the lateral meniscus was 71.4% and 100% respec-
tively. The sensitivity and specificity for the medial me-
niscus was 85.2% and 86.1% respectively. The number
of lateral menisci was very low and therefore the results
should be interpreted with caution. However, the nu mber
of medial menisci was significant so both MRI and ul-
trasound showed a high sensitivity and specificity. We
also had good sensitivity and sp ecificity for the ACL but
did not have any PCL injuries in th e series. All structures,
i.e. medial meniscus, lateral meniscus, ACL and PCL
were visualized clearly in all knees. Although there were
no PCL injuries, the PCL was clearly visualized with
ultrasound, whereas its visualization can be a problem on
MRI. As it is shown from our results, the ultrasound
findings in IDK compare well with both arthroscop y and
MRI. In some cases, as for example the PCL, we think it
was even more helpful than MRI. Ultrasound is not
widely used as a diagnostic test for knee injuries, and
there has to be a learning curve for its routine use [11,13].
Competent and experienced radiologist can diagnose
IDK with help of ultrasound rather than expensive MRI.
Ultrasound is available in all peripheral centres, where as
MRI is only available in tertiary centres. So it is better to
Table 1. Summary of results.
Lesion Arthroscopy MRI ultrasound
Torn Normal Abnormal Torn Normal Abnormal Torn Normal
LM 7 43 6 0 44 0 5 45
MM 27 23 20 5 25 7 23 20
Complete Partial Normal
ACL 20 7 23 13 7 30 3 17 30
PCL 0 0 50 0 0 50 0 0 50
LM - Lateral meni s cus; MM - Medial meniscus; ACL- Anterior cruciate ligament PCL - Posterior cruciate ligament.
Table 2. Sensitivity & specificity of MRI and ultrasound.
LESION MRI ULTRASOUND
SENSITIVITY SPECIFICITY SENSITIVITY SPECIFICITY
Lateral meniscus 85.7% 100 71.4% 100%
Medial meniscus 96.1% 95.8% 85.2% 86.1%
Anterior cruciate l ig a ment 74.1% 100 74.2% 100%
Posterior cruciate ligament N/A N/A N/A N/A

Is Ultrasound Effect iv e in Diagnosing Internal Derangements of the Knee? 324
do ultrasound rather than MRI for diagnosing IDK in
peripheral centres and refer to specialty clinics or tertiary
centres for further diagnosis and treatment [10-12].
5. Conclusion
The present study supports that the clinical diagnosis is
of primary necessity. Ultrasound and MRI are additional
diagnostic tools for diagnosing internal derangement of
knee. Arthroscopy combines more accurate diagnosing
tool and therapeutic modality, which is a more conven-
ient, economical and convinci ng t echnique to both surgeon
and patient alike. However, high expectations from pa-
tients knowing the diagnosis befor e undergoing interven-
tional procedures like arthroscopy make ultrasound and
MRI the highly demanding and needed technique in di-
agnosing IDK. MRI is considered as a more sensitive te-
chnique compared to ultrasound. However, MRI has false
and misleading results as high as 20% - 30% in knee pa-
thologies as being reported in standard literature which is
also confirmed in our study. Although ultrasound is less
accurate than MRI, it is cost effective and available at
most of the peripheral centres. We recommend that ul-
trasound be used at present as a screening test before a
MRI is performed or where clinical examination is diffi-
cult or unclear.
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