ultrasound findings of the knee joint at khartoum teaching hospital ...

Ozean Journal of Applied Sciences 5(4), 2012
Ozean Journal of Applied Sciences 5(4), 2012
ISSN 1943-2429
© 2012 Ozean Publication
ULTRASOUND FINDINGS OF THE KNEE JOINT AT KHARTOUM
TEACHING HOSPITAL, SUDAN
MUSTAFA Z. MAHMOUD 1, 2 *, ELBAGIR H. MANSSOR 1 , ALSAFI ABDULLA 3 ,
MAGDOLEEN I. SID-AHMED 4 , ABDELMONEIM SULIEMAN 1
1 Salman bin Abdulaziz University, College of Applied Medical Science, Radiology and Medical Imaging
Department, Al-Kharj- Saudi Arabia.
2 Sudan University of Science and Technology, College of Medical Radiological Science, Basic Sciences
Department, Khartoum- Sudan.
3 Sudan University of Science and Technology, College of Medical Radiological Science, Radiotherapy
Department, Khartoum- Sudan.
4 National Social Insurance Fund, Health Center, Ultrasound Department, Khartoum- Sudan.
*E-mail address for correspondence: zuhairmustafa4@hotmail.com
____________________________________________________________________________________
Abstract: Sonography has been advocated for the evaluation of superficial supporting structures about
the knee because it's a simple, rapid, inexpensive and accurate method. This study was aimed to
determine the common knee pathologies in Khartoum Teaching Hospital in patients with knee joint
symptoms.A cross sectional descriptive study was performed fromMay 2011 to May 2012. A total of 100
consecutive patients referred to the Radiology department with knee joint pathology were studied. The
patients’ socio-demographic data, clinical history and physical examination were recorded. Sonography
of the knees was done using ultrasound (U/S) machine fitted withhigh frequency linear transducers (7-10
MHz).Out of 100 patients hadknee joints evaluated sonographically. The mean age was 39±4.3 years.
Baker’s cysts were demonstrated in (82; 64.6%) of knees, joint effusion detected in (11; 8.7%), Synovitis
seen in (9; 7.0%), and bone erosion with osteophyte likely to affect (5; 3.9%) of the scanned knees.
Conditions such as bursitis and meniscal degeneration had equally incidence (3; 2.4%) in knees, while
tendon tear is the least pathology detected (1; 0.8%).High resolution MUS appears to be a reliable,
accurate, available and cost effective method for the evaluation of knee joint menisci, ligaments, tendons
and muscles in low resourced country like Sudan where magnetic resonance imaging (MRI) is expensive
and accessible only to a few.
Keywords: Baker’s cyst; Bursitis; Joint effusion; Musculoskeletal ultrasound;Osteophyte;Synovitis.
___________________________________________________________________________________
INTRODUCTION
Sonography has been employed for over six decades with few documented cases of adverse
effects(Bamett et al., 1994). It has demonstrated a long-standing record of safety and efficacy in
numerous clinical applications(Dalecki, 2004). Reports’ describing the physical, chemical and biologic
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Ozean Journal of Applied Sciences 5(4), 2012
effects of U/S date as far back as the early 1920’s and, since then, extensive research describing its
mechanisms and bioeffects has been published.Using U/Sas a clinical investigative tool started in 1950’s.
However, its application in imaging of MUS remained underutilized till 1980’s(Mamix et al., 1995).
Soft tissue pathology of the knee represents one of the more common, yet perplexing, musculoskeletal
disorders presenting at Khartoum Teaching Hospital. Knee pain and related symptoms may come as a
result of damage to one or more of the soft tissue structures that stabilize and cushion the knee joint,
including the ligaments, muscles, tendons, and menisci. Khartoum Teaching Hospital records of
2011/2012 show that averages of 500 patients with knee joint disorders were seen in orthopaedic and
rheumatology outpatient clinics out of a total of 6000 patients annually.
In a country with a population of 40 million people, it contributes significantly to the burden of disease.
The only mode of examination for these patients has been X-rays of the knee and this meant that little
information was got about the soft tissue component of the knee. U/S of the knee joint has the advantage
over Magnetic resonance imaging (MRI) in that it is cheaper, convenient and easier to use, is dynamic
and has no contra-indications to its use(Iagnocco, 2010).
U/S involves no radiation and can obtain views in multiple planes. It can also visualize soft tissue
structures like the menisci and cartilage and can yield a lot more information on the bursae, tendons,
muscles, ligaments menisci and joint space pathologies(Grassi, Lamanna, & Cervini, 1999).
METHODOLOGY
Selection and description of participants
Thiscross sectional descriptive study was performed in the period of May 2011 to May 2012. A total of
100consecutive patientsreferred to the Radiology department with knee joint symptoms were recruited.
After the nature of the exam was fully explained, informed consent was obtained from both the
consecutively enrolled outpatient and the U/S department. Also prior to samples scanning, a formal
approval was obtained from Ethics and Scientific Committee of Khartoum Teaching Hospital, Khartoum-
Sudan.
Patient characteristics; including socio-demographic data, clinical history and physical examination
findings were recorded. Patients who had no clinical evidence of knee joint pain, knee joint involvement
and other forms of inflammatory diseases were not included in this study.
Technical information identify
Sonography of the knee joints was done using General Electric (GE) medical system, logic5 expert U/S
machine (Sony Corporation, Japan). The applied U/S transducer was a linear probe of a frequency 7.5-10
MHz, made by the Yokogawa medical system, Ltd. 7-127 Asahigaoka 4-chome Hino-shi Tokyo, Japan.
Model 2302650 with serial number of 1028924YM7 and manufactured date of April 2005. Printing
facility issued through U/S digital graphic printer, 100 V; 1.5 A; and 50/60 Hz. Made by Sony
Corporation- Japan, with serial number of 3-619-GBI-01.
U/S images were recorded on a hard copy and the films were independently reviewed by two radiologist
and results combined therefore. However, there was no statistically significant interobserver variation.
The knee joint was examined by the Technical Guidelinesofthe European Society of Musculoskeletal
Radiology (ESSR)(Ian et al., 2012),comprehensively in different scanning approaches: 1. Anterior knee
approach to assess the quadriceps tendon, supra-patellar and para-patellar recesses, femoral trochlea,
patellar retinacula and patellar medial articular facet, patellar tendon. 2. Medial knee approach used to
study medial collateral ligament and pes anserinus tendons.3. Lateral knee approach used to evaluate the
iliotibial band and lateral collateral ligament. 4. Posterior knee approach used to check the medial
tendons, semimembranosus- gastrocnemius bursa, popliteal neurovascular bundle and intercondylar fossa,
posterolateral corner and biceps femoris and peroneal nerve.
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Ozean Journal of Applied Sciences 5(4), 2012
The sonographic appearance of joint fluid, synovitis, loose bodies, bursae and cysts, tendon, mensci and
ligament pathology was recorded. For each position, transverse and longitudinal views were done.
Doppler was used to distinguish viability of the tumour by demonstrating flow from the haematomas.
Statistical analysis
All statistical analysis was performed using Microsoft Excel Software and the standard Statistical
Package for the Social Sciences (SPSS Inc., Chicago, IL, USA) version 15 for windows. Results were
described as means, standard deviations (SD); mean±SD and percentages in a form of comparison tables
and graphs.
RESULTS
A total of 100 patients with knee complications were recruited in the study. Females were 75 (75%) were
while 25 (25%) were males. The males: female ratio was 3:1. Their ages ranged from 20 to 83 years; the
mean age was 39±4.3 years. The peak age was in 36-50 years age group which accounted for 43 (43%)
cases. (Table 1, Table 2 and Figure 1).
Table 1: Frequency and percentage of genders
Gender Percentage (%)
Female 75.0
Male 25.0
Total 100.0
Table2: Distribution of patients’ age
Age ranges (Years) Percentage (%)
20 – 35 13.0
36 – 51 43.0
52 – 67 40.0
68 – 83 4.0
Total 100.0
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Percentage
Ozean Journal of Applied Sciences 5(4), 2012
50%
40%
43; 43%
40; 40%
30%
20%
13; 13%
Frequency; Percentage (%)
10%
0%
4; 4%
20 - 35 36 - 51 52 - 67 68 - 83
Age ranges (year)
Figure 1: Distribution of patients’ age
A painful swollen knee was the commonest presenting clinical complaint by (65.4%). While pain alone
was the second commonest symptom (34.6%)(Table 3). Complication of knee joint pathology was
bilateral in 27 patients while 73 patients had pathology unilaterally in one knee; a total of 127 knees were
scanned. Out of 100 patients 87 (87.0%) scanned had pathology in the knee joints while 13 (13.0%) had
normal knee joints. Abnormal knee joints seen in those above 38 years while those below this group all
the knee joints had no pathology.
MUS findings in 100 patients are presented in (Table 3 and Figure 2). From the 127 scanned knees,
Baker’s cystswere demonstrated by MUS in (82; 64.6%) of knees. Joint effusion detected in (11; 8.7%),
Synovitis seen in (9; 7.0%), bone erosion and osteophyte likely to affect (5; 3.9%) of the scanned knees.
Conditions such as Bursitis and meniscal degeneration had equally incidence (3; 2.4%) in knees. Tendon
tear is the least pathology detected in (1; 0.8%). A total of 87 cases were diagnosed with U/S as abnormal,
29 of which had normal X-ray findings.
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Percentage (%)
Ozean Journal of Applied Sciences 5(4), 2012
Table 3: Clinical and musculoskeletal ultrasound findings
Clinical findings
Percentage (%)
Painful swollen knee
(65.4)
Painful swollen knee
(34.6)
Total
(100.0)
MUS findings in 127 knees
No abnormality detected (NAD)
Baker’s cysts
Effusion
Synovitis
Bone erosion and osteophyte
Bursitis
Meniscal degeneration and tear
Tendon tear
Total
Percentage (%)
(10.2)
(64.6)
(8.7)
(7.0)
(3.9)
(2.4)
(2.4)
(0.8)
(100.0)
75,00%
64,60%
60,00%
45,00%
30,00%
Musculoskeletal ultrasound
Findings in 127 knees
15,00%
10,20% 8,70% 7,00% 3,90% 2,40% 2,40% 0,80%
0,00%
Figure 2: Musculoskeletal ultrasound findings
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Ozean Journal of Applied Sciences 5(4), 2012
DISCUSSION
In this study, the commonest clinical complains were found to be knee joint pain and swelling. This was
similar towhat was observed by (Verena & Sarah, 2001).In our series of 100 patients whoundergone U/S
of their knees, more females presented for U/S of the knee than males. In the light of the fact that obesity
is one of the main indications of knee joint pain, the vast majority of the patients are females. At the same
time, it is known that a number of women present with arthropathies followingpregnancy, obesity and
post-menopausal osteoporosis (Hannan et al., 2000).
Spectrums of MUS knee findings were demonstrated. Although the authors found degenerative bone
erosion and osteophyte occurred in patients of 40 years and above.These findingswere differed from
(Harry & Joseph, 1999) study that reported itis usually uncommon in the age group 41-50. U/S was able
todetect early degenerative processes where plain radiographs were reportedly normal.
The incidence of Baker's cysts in our study group was (64.6%) of knees. This finding was higher than the
findings reported by (Naredo et al., 2005) in a population based study where Baker’s cysts were detected
in (22%) of knees in Spanish patients, andalsowas higher than prevalence reportedby(Fam, Wilson, &
Holmberg, 1982), where they noted a (42%) rate in German population. The authors believe that the high
prevalence rate ofBaker's cysts were due to the reasons that the number of women represented 57% of the
sample with an average age above forty, these reasons are compatible with different severities of knee
osteoarthritis (OA) lead to the develop of suchcysts.
Study done by (Eric, Jacobson, David, Curtis, & Mamix, 2001) had shown that identification of fluid
between the semimembranosus andmedial gastrocnemius tendons in communication with posterior knee
cysts indicates Baker's cysts with100% accuracy. In this study, these features were demonstrated in all
cases where the Baker’s cysts werefound.
Effusions were seen in (8.7%) of scanned knees. U/S has a high accuracy foridentification and
characterization of joint effusions (Chhem & Beauregard, 1995). Bursitis was reported in (2.4%) cases.
Bursitis has been reported to be due to kneeling in the upright posture. It was characteristically noted that
more females got the bursitis compared to males. Presence of increased flow on color or power Doppler
imaging or tenderness during transducer palpation noted by (Ptasznik, 1999) which was an indicative of
an inflammatory state consistent with true bursitis.
Ultrasonographic detection of synovitis in the knee has already been reported (Karim et al., 2004). Our
findings reported (7.0%) cases of synovitis, further suggest that measurement of synovial thickness is an
adequate method of quantifying synovitis.MRI is now considered to be the most valuable methodfor
monitoring synovitis (Peterfy, 2003). Ultrasonography allows less comprehensiveanatomical coverage
within individual joints, buthas the advantages of higher resolution of soft tissuearchitecture. It is also
readily available, costs less, and maybe undertaken by rheumatologists.
Although the relation between synovitis and joint damageremains controversial (Ostergaard et al., 1999),
recent MRI studies have shown thateffective suppression of synovitis can reverse structuraldamage and
that there is a threshold level of synovitis forthe progression of bony damage (Conaghan et al., 2003). It
could be confirmed that using standardised anatomical guidelines, thecombined grey scale and power
Doppler ultrasonographicmethod has indeed shown itself to be sensitive in detectingtime dependent
rheumatoid and synovialchanges (synovitis) in individual joints in response to therapy, parallelingchanges
in disease activity.
A percentage of (2.4%) of meniscal degeneration and tear was detected in patients. Reports reveal that
majority of cases developed knee joint meniscal tears because the meniscus has such important functions
in load bearing and stability of the knee, loss of this structure in the young is associated with significant
degenerative changes which may be depicted on U/S in addition to meniscal pathology (Maffuli,
Petricciuolo & Pintore, 1991).Such justification exactly matches our findings in this study.Observations at
U/S and patient clinical history about tendon tear (0.8%) were similar to results obtained by (Rasmussen,
1999). Wherethe major causative factors of such condition was due to traumatic origin resulting in
avulsion of fragments of cartilage and bone from the tibial tuberosity.
Limitation of this study was the inherentoperator dependence in the acquisition of the sonographic data
and images. In addition,MRI imaging was not used as the gold standard in our study.
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Ozean Journal of Applied Sciences 5(4), 2012
In conclusion high resolution MUS appears to be a reliable, accurate, available and cost effective method
for the evaluation of knee joint menisci, ligaments, tendons and muscles in low resourced country like
Sudan where MRI is expensive and accessible only to a few patients.Although Baker's cysts are common
finding in knee joint, but they may not be found on physical examination. Thus MUS should be more
widely employed by clinicians in the diagnosis of Baker's cysts.
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