RHEUMATOLOGY
Rheumatology 2012;51:vii22–vii25
doi:10.1093/rheumatology/kes330
Soft tissue pathology: regional pain syndromes,
nerves and ligaments
George A. W. Bruyn1, Ingrid Moller2, Andrea Klauser3 and Carlo Martinoli4
Abstract
Musculoskeletal ultrasonography (MSUS) is a useful imaging technique in the diagnosis of various soft
tissue pathologies. High-frequency linear array transducers provide excellent resolution of soft tissue
pathology. Pathological changes in subcutaneous tissue, including soft tissue tumours, abscesses, tenosynovitis, ligamentous and tendinous abnormalities, and peripheral nerve lesions, including carpal tunnel
syndrome, can be identified. This review addresses the role of US in diagnosing regional pain syndrome,
ligament lesions and nerve lesions.
Key words: ultrasonography, soft tissue lesions, rheumatological disorders, nerve lesion, ligament, regional
pain syndrome, peripheral neuropathy, Stener lesion, rotator cuff disease, trigger finger.
Introduction
This review covers a range of soft tissue disorders where
high-resolution ultrasonography (US) can be helpful for the
differential diagnosis, i.e. regional pain syndromes, ligament disorders and nerve lesions. The occurrence of
soft tissue pathology is not infrequent: in the Mexican
adult population, the overall prevalence of regional rheumatic pain syndrome has been reported as 5% [1]. The
most frequently observed disorder was rotator cuff disease (2.4%), followed by plantar fasciitis (0.6%), lateral
epicondylalgia (0.6%), medial epicondylalgia (0.5%), trigger finger (0.4%), carpal tunnel syndrome (0.4%), anserine
bursitis (0.3%), de Quervain’s syndrome (0.3%), shoulder
bicipital tendinopathy (0.3%), trochanteric syndrome
(0.1%) and Achilles tendinopathy (0.1%). In persons with
inflammatory rheumatic diseases, common soft tissue
disorders are plantar fasciitis, de Quervain’s syndrome
and trigger finger [2].
Soft tissue pathology usually presents with symptoms of pain and swelling; its origin may be highly
variable, ranging from inherited disorders, infection and
inflammation to trauma and sports-related disorders.
1
Department of Rheumatology, MC Groep Hospitals, Lelystad, The
Netherlands, 2Department of Rheumatology, Instituto Poal de
Reumatologia, Barcelona, Spain, 3Department of Radiology, Medical
University of Innsbruck, Austria and 4Department of Radiology,
University of Genoa, Genoa, Italy.
Submitted 28 January 2012; revised version accepted
12 October 2012.
Correspondence to: George A. W. Bruyn, Department of
Rheumatology, MC Groep Hospitals, 8233 AA Lelystad, The
Netherlands. E-mail: [email protected]
Practical considerations are the use of a standard US
protocol [3], bilateral study of the extremities in order to
compare the affected side with the normal side and dynamic studies, e.g. in examining tendons or muscles.
Musculoskeletal US (MSUS) can also be of value in the
treatment of various soft tissue lesions. Examples that are
often treated using US-guided injection are subacromialsubdeltoid bursitis (Fig. 1), greater trochanteric bursitis,
various forms of tenosynovitis, soft tissue calcifications,
plantar fasciitis and carpal tunnel syndrome. The echogenicity of the soft tissue lesion is often hypoechoic,
which acoustically contrasts with the isoechogenicity
of the surrounding tissue and the bright, hyperechoic
needle.
Regional pain syndromes
Regional pain syndrome (RPS) comprises a wide spectrum of pathologies located in different anatomical regions
such as the shoulder, knee, elbow, heel or greater trochanter. They represent one of the most common forms
of musculoskeletal complaints encountered by the
rheumatologist [4, 5]. RPS nomenclature is confusing
and there is no uniform agreement as to the characteristics of each syndrome; furthermore, the causes of many of
them have not been clearly elucidated. The diagnosis
of RPS is dependent on the clinical findings, but unfortunately clinical examination is not highly specific. Therefore
both MRI and US are excellent methods to explore the
morphological alterations of the soft tissue in patients
with RPS to correlate the patient’s symptoms with the
alterations noted in the images.
! The Author 2012. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: [email protected]
Soft tissue pathology
FIG. 1 Bicipital tendinopathy.
Transverse 12.5- MHz image of the biceps tendon (BT)
with loss of the characteristic pattern short axis of uniform
fine stippling compatible with tendinopathy. The fluid-filled
bicipital tendon sheath (BTS) surrounds the BT. Both of
these findings may represent indirect evidence of rupture
of the rotator cuff. A small amount of fluid is also noted in
the adjacent and partially overlying the subacromial–
subdeltoid bursa (SDB). The deltoid muscle (DM) overlies
these structures.
There are some general principles that can be applied
when RPS is evaluated by US:
. A knowledge of anatomy is essential to identify the
pathological changes of RPS.
. Sonopalpation, the application of pressure with the
probe over specific visualized anatomical structures
within the region to accurately localize the painful
and/or tender structure, may provide further insight
as to the source of the pain. Comparison with the
uninvolved side may be helpful.
. Tendinopathy or enthesopathy with or without bursitis
is a common finding in US examination of RPS and
range from alteration in the fibrillar tendon pattern to
partial and full-thickness tears of the tendon.
. Various structural characteristics of individual tendons
may be of significance, both clinically and ultrasonographically, in RPS, including the presence of a synovial sheath or paratenon (e.g. flexor digitorum
tendons of the MCP joint level vs the Achilles
tendon), the presence of a bursa at the tendinous insertion (e.g. the distal bicipital tendon), intra- or
extra-tendinous fibrocartilage (e.g. within the tibialis
posterior tendon as it wraps around the medial malleollus) or the presence of a retinaculum restraining a
group of tendons (e.g. the flexor or extensor retinacula
in the wrist or ankle).
. In regions of multitendon attachment, whether related
to different tendons (e.g. at the lateral epicondyle or
overlapping insertion of the gluteus medius–gluteus
minimus at the junction of the anterior and lateral
facet of the greater trochanter) or multiple fascicle tendons (e.g. subscapularis), the sonologist needs to alter
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probe orientation to follow the individual tendon element to avoid anisotropy.
. A myotendonous junction may be quite variable and
distal, with the presence of muscle fibres and multiple
tendon bands at the tendon attachment generating a
heteroechoic appearance (e.g. the subscapularis).
. A bony landmark such as the triangular shape formed
by the junction of the anterior and lateral facets of the
greater trochanter in the transverse plane or the bicipital groove at the shoulder is a helpful starting point
to perform a US systematic evaluation in RPS.
. Finally, dynamic evaluation is essential in all RPS to
optimize tendon and ligamentous visualization and elucidate even small abnormalities (e.g. abduction
against resistance of the gluteus medius enhances
US visualization of the central gluteus medius tendon
insertion at the superior posterior facet of the greater
trochanter).
Ligament lesions
The primary function of ligaments is to connect bone to
bone. If a ligament is stretched, or torn, then too much
movement between bones may occur. This extra movement is perceived as a popping, clicking, catching or feeling of weakness. The most common traumatic ligament
affection are lateral and medial ankle ligaments in acute
and chronic ankle sprains, injuries to the distal tibiofibular
syndesmosis, collateral finger ligaments (skier’s thumb,
collateral ligaments in the thumb), the medial collateral
ligament of the knee and the ulnar collateral ligament of
the elbow (pitcher’s elbow).
US is able to delineate ligaments by their homogeneous
and regular echoic striated appearance, very similar to the
behaviour of tendons, by showing anisotropy, especially
at their bony insertion points.
Stretched ligaments show hypoechoic irregular thickening, can present with or without hyperaemia;
periligamentous fluid may be present, as well as partial
bony avulsions or bony irregularities.
In acutely torn ligaments, often bony avulsions on one
side of the ligament insertion can be seen, with hypoechoic thickening of the torn end and consecutive thinning.
The gap of the rupture can be seen as well, and may be
located at the bony insertion or in the mid-portion of the
ligament. Dynamic US with active stretching of the ligament might be very helpful to establish the diagnosis of a
full-thickness ligament tear or even to show a displaced
ligament. Differentiation of a displaced ligament is important and affects therapeutic management in conditions like
the Stener lesion of the thumb, where surgery should be
performed on displaced ligaments [6]. In ulnar collateral
ligament injuries of the elbow, valgus stress might increase diagnostic confidence to ensure humeroulnar
joint gapping in injured elbow ulnar collateral ligaments [7].
The medial collateral ligament of the knee is well suited
for US assessment because of its superficial location. It
can be severely injured in sports when an excessive force
is applied on a flexed valgus and extrarotated knee.
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George A. W. Bruyn et al.
Usually the proximal superficial part is affected as well as
the deep meniscofemoral ligament. A three-grade scale
has been proposed: grade 1, ligament stretching without
laxity; grade 2, partial discontinuity and moderate instability; and grade 3, complete discontinuity and marked
instability.
In chronic torn ligaments, echogenicity can vary from
hypo- to iso- and hyperechoic, mainly representing scar
tissue, with small calcifications or avulsed bony flakes. In
non-healing lateral ankle sprains, US can detect signs of
anterolateral impingement with synovitis and fluid in the
anterolateral recess caused by insufficient anterior talofibular ligament healing [8].
Healing of the femoral insertion of the superficial medial
collateral knee ligament can result in the formation of a
calcification (Pellegrini–Stieda lesion) that can be demonstrated well using US [9].
Ligaments can be also painful when affected by enthesopathy in terms of SpA. In these conditions, small cortical irregularities due to osteoproliferative and erosive
processes might be seen, with slight hyperaemia and
hypoechoic thickening of the ligament itself [10].
In summary, US is able to depict superficially located
ligaments of peripheral joints. US can be used to grade
and describe several conditions of injured ligaments with
direct therapeutic impact in the acute and chronic
setting [11].
Nerve lesions
In the past few years the diagnostic potential of US for the
evaluation of peripheral neuropathies has expanded significantly. An increasing number of articles dealing with
the assessment of subtle pathological abnormalities (e.g.
disimmune neuropathies, inherited disorders, unusual entrapment syndromes) and the evaluation of minor nerves
(e.g. musculocutaneous, palmar cutaneous branch of the
median, anterior and posterior interosseous, lateral femoral cutaneous and so forth) are rapidly accumulating in
the literature (Fig. 2). At the same time, the quantification
provided by the calculation of nerve diameter and
cross-sectional area has extended far beyond the evaluation of the carpal and cubital tunnels with the aims of
(i) determining normal size ranges for the main nerve
trunks of the upper and lower extremities; (ii) establishing
threshold values in a variety of neuropathies and
(iii) matching morphological data with conduction velocities and clinical findings.
Although little comparison still exists with MRI in this
field, US has definite intrinsic advantages over MRI,
such as a higher spatial resolution—a factor leading to a
more confident depiction of abnormalities affecting small
sensory nerves—the ability to explore long nerve segments in a single study and the ability to examine tissues
dynamically during joint and muscle activity. With regard
to electrophysiology, which represents the clinical gold
standard for nerve assessment, there is increasing insight
that the use of electromyography and US is strongly converging regardless of the patient’s disorder and that combining these techniques will redefine the way nerve
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FIG. 2 Nerve compression.
Long-axis 17.5- MHz US image of the elbow demonstrates focal compression (arrow) of the posterior interosseous nerve (arrowheads) proximal to the supinator
tunnel by a fibrous band. Note the excellent resolution of
the US image by comparing the abnormality with the scale
bar on the bottom right side of the image.
diseases are conceptualized and managed. Considering
the current literature, if we refer to the efficacy of nerve US
as assessed using the Thornbury’s six-tiered hierarchical
model of efficacy [12], most nerve disorders have now
passed level I (technical efficacy) and level II (diagnostic
accuracy efficacy). An increasing number of articles dealing with a variety of clinical settings are now addressing
level III (diagnostic thinking efficacy), in which one establishes whether the imaging modality helps to strengthen or
change the clinician’s differential diagnosis, and level IV
(therapeutic efficacy), in which the actual impact of US on
patient management is determined.
As a measure of the clinical impact of this modality, a
recent prospective study on 130 patients with peripheral
neuropathies revealed that US modified the diagnostic
and therapeutic paths in approximately two-fifths of
cases [13]. In another series of 77 patients with mononeuropathy, US helped to confirm or extend diagnostic
findings in about half of the cases by providing otherwise
undetectable anatomical information and contributed to
redirect diagnosis and therapy in 25% of cases by showing where and how to operate [14]. These results indicate
that US is actually becoming an essential part of the diagnostic workup of peripheral neuropathies. Dedicated systems and new prototypes designed to combine US
imaging and neurophysiological assessment in one machine are in development. It is expected that the integration of parameters derived from the sum of the two
modalities will open unexpected perspectives, allowing
improved understanding of the pathophysiology of nerve
disorders and serving as a more objective outcome
measure.
At the same time, many specialists are now increasingly
involved in the practice of nerve US, including anaesthesiologists, musculoskeletal radiologists, neurologists, neuroradiologists, neurosurgeons, physical medicine and
rehabilitation specialists and possibly rheumatologists. In
the near future this will bring many relevant educational
implications, particularly with regard to training and
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Soft tissue pathology
competency assessment. The current state is a challenge
that needs to be addressed by the different disciplines
with shared educational and training programmes to
obtain consensus agreement among expert practitioners
and recommendations for best practice [15].
In conclusion, US has an ideal focus for the diagnosis of
soft tissue pathology. The two distinct features that make
the difference are its real-time dynamic capability and the
high resolution.
Rheumatology key messages
MSUS is capable of diagnosing most soft tissue
pathology.
. MSUS influences clinical decision-making in peripheral neuropathy.
. MSUS is useful in detecting trigger finger, de
Quervain’s disease and plantar fasciitis.
.
Supplement: This paper forms part of the supplement
‘Ultrasound in rheumatology: the future is now’. This supplement was supported by an unrestricted educational
grant by the Fundación Española de Reumatologı́a.
Disclosure statement: The authors have declared no
conflicts of interests.
References
1 Alvarez-Nemegyel J, Pelaez-Ballestas I, RodriguezAmado J et al. Prevalence of rheumatic regional pain
syndromes in adults from Mexico: a community survey
using COPCORD for screening and syndrome-specific
diagnostics criteria. J Rheumatol 2011;86:15–20.
2 Siddiq AB, Hasan SA, Das G, Khan AU. Interventional pain
management in rheumatological disease—a three years
physiatric experience in a tertiary medical college hospital
in Bangladesh. Korean J Pain 2011;24:205–15.
3 Bruyn GAW, Schmidt WA. Introductory guide to musculoskeletal ultrasound for the rheumatologist. Houten: Bohn
Stafleu Van Loghum, 2012.
www.rheumatology.oxfordjournals.org
4 Hazleman BL, Riley J, Speed CA, eds. Soft tissue rheumatology. Oxford: Oxford Universty Press,
2004.
5 Bianchi S, Martinoli C, Abdelwahab IF. Ultrasound of
tendon tears. Part 1: general considerations and upper
extremity. Skeletal Radiol 2005;34:500–12.
6 Ebrahim FS, De Maeseneer M, Jager T et al. US diagnosis
of UCL tears of the thumb and Stener lesions: technique,
pattern-based approach, and differential diagnosis.
Radiographics 2006;26:1007–20.
7 Nazarian LN, McShane JM, Ciccotti MG et al. Dynamic US
of the anterior band of the ulnar collateral ligament of the
elbow in asymptomatic major league baseball pitchers.
Radiology 2003;227:149–54.
8 Allison SJ, Nazarian LN. Musculoskeletal ultrasound:
evaluation of ankle tendons and ligaments. Am J
Roentgenol 2010;194:W514.
9 Lee JI, Song IS, Jung YB et al. Medial collateral ligament injuries of the knee: ultrasonographic findings.
J Ultrasound Med 1996;15:621–5.
10 Wakefield RJ, Balint PV, Szkudlarek M et al.
Musculoskeletal ultrasound including definitions for
ultrasonographic pathology. J Rheumatol 2005;32:
2485–7.
11 Nazarian LN. The top 10 reasons musculoskeletal
sonography is an important complementary or
alternative technique to MRI. Am J Roentgenol 2008;190:
1621–6.
12 Thornbury JR. Clinical efficacy of diagnostic
imaging: love it or leave it. Am J Roentgenol 1994;
162:1–8.
13 Padua L, Liotta G, Di Pasquale A et al. Contribution of
ultrasound in the assessment of nerve diseases. Eur J
Neurol 2012;19:47–54.
14 Padua L, Aprile I, Pazzaglia C et al. Contribution of ultrasound in a neurophysiological lab in diagnosing nerve
impairment: a one-year systematic assessment. Clin
Neurophysiol 2007;118:1410–6.
15 Padua L, Martinoli C. From square to cube. Clin
Neurophysiol 2008;119:1217–8.
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