393
REVIEW ARTICLE
The importance of magnetic resonance arthrography in the diagnosis of shoulder joint instability
Copyright (c) 2022 Slovenian Medical Journal. This work is licensed under a
Creative Commons Attribution-NonCommercial 4.0 International License.
The importance of magnetic resonance arthrography in 
the diagnosis of shoulder joint instability
Pomen magnetnoresonančne artrografije pri diagnosticiranju nestabilnosti 
ramenskega sklepa
Karmen Žiberna, Vladka Salapura
Abstract
The shoulder joint is the most mobile joint in the human body due to its structure, but for the same reason, it is also the 
most unstable joint. With complete or incomplete shoulder dislocations, the joint stabilizers are damaged. That makes the 
joint even more unstable, which leads to a vicious circle. Shoulder joint instability is often a problem for young people, 
especially athletes, so an accurate diagnosis of the trauma of small intra-articular structures is crucial for treating shoulder 
instability. The most established diagnostic method for shoulder instability is MR arthrography under the supervision of 
fluoroscopy. In recent years, with the rapid development of ultrasound technology, significant progress has been made, 
especially in the quality of high-frequency linear probes, which allows us to display small soft tissue structures accurately. 
The latter enabled the development of minimally invasive procedures, especially in the musculoskeletal organ system, in 
which precision and transparency are indispensable, and which include arthrography.
Izvleček
Ramenski sklep je zaradi svoje zgradbe najbolj gibljivi sklep v človeškem telesu, hkrati pa tudi najbolj nestabilen. Ob po-
polnih ali nepopolnih izpahih rame pride do poškodbe stabilizatorjev sklepa. To pomeni, da je sklep še dodatno nesta-
bilen, kar vodi v začarani krog. Nestabilnost ramenskega sklepa je pogosto tudi problem mladih, predvsem športnikov, 
zato je pred zdravljenjem nestabilnosti rame izjemno pomembno natančno diagnosticirati poškodbe drobnih struktur v 
sklepu. Standardno uveljavljena diagnostična metoda pri nestabilnosti rame je magnetnoresonančna artrografija (MR-
artrografija) pod nadzorom fluoroskopije. V zadnjih letih je ob hitrem razvoju ultrazvočne tehnologije prišlo do velikega 
napredka v kakovosti visokofrekvenčnih linearnih sond, ki nam omogočajo natančen prikaz drobnih mehkotkivnih struk-
tur. Slednje je, zlasti na področju mišično-skeletnega organskega sistema, omogočilo razvoj minimalno invazivnih pose-
gov, pri katerih je natančnost in preglednost še posebno potrebna, mednje pa sodijo tudi artrografije.
Clinical Institute of Radiology, University Medical Centre Ljubljana, Ljubljana, Slovenia
Correspondence / Korespondenca: Karmen Žiberna, e: karmenziberna@gmail.com
Key words: glenohumeral joint; shoulder instability; magnetic resonance arthrography; contrast agent
Ključne besede: glenohumeralni sklep; ramenska nestabilnost; magnetnoresonančna artrografija; kontrastno sredstvo
Received / Prispelo: 21. 2. 2021 | Accepted / Sprejeto: 21. 7. 2021
Cite as / Citirajte kot: Žiberna K, Salapura V. The importance of magnetic resonance arthrography in the diagnosis of shoulder joint 
instability. Zdrav Vestn. 2022;91(9–10):393–7. DOI: https://doi.org/10.6016/ZdravVestn.3233
eng slo element
en article-lang
10.6016/ZdravVestn.3233 doi
21.2.2021 date-received
21.7.2021 date-accepted
Diagnostics Diagnostika discipline
Review article Pregledni znanstveni članek article-type
The importance of magnetic resonance 
arthrography in the diagnosis of shoulder joint 
instability
Pomen magnetnoresonančne artrografije pri diag-
nosticiranju nestabilnosti ramenskega sklepa article-title
The importance of magnetic resonance 
arthrography in the diagnosis of shoulder joint 
instability
Pomen magnetnoresonančne artrografije pri diag-
nosticiranju nestabilnosti ramenskega sklepa alt-title
glenohumeral joint, shoulder instability, mag-
netic resonance arthrography, contrast agent
glenohumeralni sklep, ramenska nestabilnost, 
magnetnoresonančna artrografija, kontrastno 
sredstvo
kwd-group
The authors declare that there are no conflicts 
of interest present.
Avtorji so izjavili, da ne obstajajo nobeni 
konkurenčni interesi. conflict
year volume first month last month first page last page
2022 91 9 10 393 397
name surname aff email
Karmen Žiberna 1 karmenziberna@gmail.com
name surname aff
Vladka Salapura 1
eng slo aff-id
Clinical Institute of Radiology, 
University Medical Centre 
Ljubljana, Ljubljana, Slovenia
Klinični inštitut za radiologijo, 
Univerzitetni klinični center 
Ljubljana, Ljubljana, Slovenija
1
Slovenian Medical Journallovenian Medical Journal
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DIAGNOSTICS
Zdrav Vestn | September – October 2022 | Volume 91 | https://doi.org/10.6016/ZdravVestn.3233
1 Introduction
The shoulder joint is one of the most functionally 
and structurally complex joints, playing an important 
biomechanical role in multiple daily activities as it con-
nects the upper limb with the torso. Due to the discrep-
ancy in articular surface size and lax articular capsule, 
it is both simultaneously the most mobile and least sta-
ble joint. Shoulder joint instability is a common clinical 
problem, manifesting mostly with pain, reduced range 
of motion and recurrent dislocations of the affected 
joint (1).
Shoulder instability can occur after an injury. Insta-
bility is normally unidirectional, i.e. anterior or pos-
terior. Instability can also be multidirectional, which 
can be a consequence of congenital structural shoulder 
joint abnormalities, repeated microtrauma or connec-
tive tissue disease (constitutional instability), e.g. in 
Ehlers–Danlos syndrome or lax connective tissue. The 
dislocation is in the anterior-inferior direction in 95% 
of cases, and is typical in falls on an outstretched arm or 
as a consequence of a direct blow to the shoulder from 
the posterior side (11). In 3% of cases, the dislocation 
is posterior, most commonly in young athletes, par-
ticularly swimmers, volley ball players, discus or ball 
throwers and martial arts competitors (3,12). Damaged 
stabilizers no longer provide optimal support, so these 
athletes are also more likely to have shoulder joint inju-
ries and sprains later in their careers. Posterior disloca-
tion can also be caused by severe muscle spasms during 
an epileptic seizure or electric shock (1). Otherwise, 
dislocations can also be superior, inferior or multidi-
rectional (12).
The diagnosis of shoulder instability is difficult and 
at the same time extremely important, as it involves 
damage to small intra-articular structures that signifi-
cantly contribute to joint stability. Due to their small 
size and intra-articular location, they are difficult to 
visualize. The main diagnostic method for an unstable 
shoulder joint is magnetic resonance (MR) arthrogra-
phy (13).
2 Magnetic resonance arthrography
MR arthrography is a minimally invasive proce-
dure with high diagnostic reliability, with which we 
can evaluate intra-articular microtrauma that most 
commonly occurs in partial or complete shoulder joint 
dislocations (5). The direct intra-articular injection of a 
contrast agent distends the joint capsule and separates 
intra-articular structures that otherwise lie in close 
contact with each other and are therefore difficult to 
visualize without contrast (2).
There are two types of arthrography: direct and in-
direct. In MR arthrography with intra-articular con-
trast injection the joint capsule is distended, allowing 
visualization of small intra-articular structures. There-
fore, direct arthrography is intended for the evaluation 
of small intra-articular structures. In the Slovenian 
healthcare services code list, MR arthrography is list-
ed as MRI of bone, arthrography, each joint: VZS code: 
1775.
In MRI with contrast, the contrast agent is inject-
ed into a peripheral vein, as the procedure is intend-
ed mainly to evaluate structural changes of bone and 
peri-articular soft tissues. This is needed particularly in 
case of suspected bone and soft tissue tumours or in 
inflammatory processes and their complications (ab-
scesses, bone sequestra, etc.).
Arthrography has been used for many years in di-
agnosing joint pathology. It was introduced in 1933 by 
Oberholzer, who used air as a negative contrast agent 
(4,6). Arthrography has gained great importance in 
the diagnosis of patients with shoulder joint instability 
with the introduction of water-soluble iodine contrast 
agents. In 1975, Schneider and colleagues presented a 
technique with an anterior approach under the control 
of fluoroscopy, which is still used today (4,7). With the 
development of ultrasound technology and the growing 
awareness of the consequences of ionizing radiation, 
ultrasound-guided arthrography has begun to gain 
ground in clinical practice in recent years. The main 
technical and clinical advantages of ultrasound-guided 
MR arthrography are the ability to examine the joint 
and surrounding soft tissues before contrast injection, 
the possibility of following the needle placement in real 
time; furthermore, an iodine contrast agent is not re-
quired and the patient is not exposed to ionizing radia-
tion (18). The main advantage of the posterior over the 
anterior approach is that it avoids anterior joint struc-
tures. These are most commonly damaged in shoulder 
joint instability, as anterior instability accounts for as 
much as 95% of all cases. Another advantage is that 
even when there is extravasation of the contrast it does 
not obscure the anterior joint structures, which pre-
serves the diagnostic image value.
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2.1 Magnetic resonance arthrography 
approaches
In the standard anteroinferior approach (Schneider 
technique) we enter the joint at the border between the 
lower and middle third of the glenohumeral joint. The 
patient is in the supine position with his shoulder in a 
neutral position or in external rotation. In the latter, the 
long head of biceps tendon is displaced laterally in order 
to gain more space for needle insertion. Under fluoros-
copy guidance, the needle position is confirmed with an 
injection of 1–2 mL of iodine contrast. With the needle 
in a correct position, 10–12 mL of paramagnetic contrast 
is injected (13). The standard anteroinferior approach is 
the most established arthrography technique, but there is 
a high probability of damage to the anteroinferior struc-
tures or stabilizers, such as m. subscapularis, labrum and 
the inferior glenohumeral ligament (IGHL), which are 
most commonly damaged in shoulder instability. There-
fore, the risk of misinterpretation is much greater (10).
Contrast can also be injected into the joint with an 
adapted form of the standard anterior technique by tar-
geting the upper half of the joint at the rotator cuff inter-
val (7). This is a triangular space at the superior medial 
part of the head of the humerus, bounded by the ten-
dons of m. supraspinatus and m. subscapularis, in which 
the coracohumeral bond and superior glenohumeral 
ligament (SGHL) are contained, along with the tendon 
of the long head of biceps muscle (8). The rotator cuff 
interval is closer to the surface, so the needle’s path is 
shorter. At the same time, external rotation of the shoul-
der displaces the biceps tendon, which prevents injuries.
Furthermore, physician can also use the posterior 
approach, in which the patient lies on their unaffected 
side. Abduction and internal rotation of the affected arm 
by 90° relaxes the shoulder girdle muscles. The needle 
is inserted vertically in the inferior-medial quadrant of 
the upper arm until it hits the cartilage of the proximal 
humerus (14). The posterior approach is also used in an-
terior shoulder instability, as it avoids labrum and IG-
HL injuries; there is also less contrast extravasation. The 
procedure is also less stressful for patients as they do not 
see the needle (9).
Ultrasound-guided arthrography, which has become 
established in recent years, has many advantages. Even 
before the arthrography, we can examine the joint for 
effusion. During the procedure itself, we can follow the 
needle placement in real time. Therefore, needle inser-
tion is easier and safer compared to the fluoroscopy 
guided approach. An additional advantage is the absence 
of the radioactive iodine contrast agent (10).
The success rate of contrast administration is almost 
100% in all imaging-controlled approaches (fluorosco-
py-guided with anterior and posterior approach and ul-
trasound-guided with anterior and posterior approach). 
Therefore, the chosen technique should be based pri-
marily on the expected pathology and patient cooper-
ation (10).
Several authors compared fluoroscopy-guided and 
ultrasound-guided arthrography. A study by Rutten et 
al evaluated the variability of intra-articular contrast 
injection success rate, number of contrast injection at-
tempts, extravasation volume and its impact on image 
interpretation, procedure duration and pain. The study 
included 100 patients with shoulder joint instability. The 
first attempt with ultrasound guidance was successful 
in 94% of subjects, while the first attempt under fluo-
roscopy guidance was successful in only 72%. They also 
compared the success of intra-articular contrast injec-
tion from the anterior and posterior sides. In the first 
attempt, 76% of anterior and 68% of posterior arthrog-
raphies were successful under fluoroscopy guidance. 
Under ultrasound guidance, the first attempt was more 
successful: 96% with the anterior approach and 92% 
with the posterior approach. They concluded that the 
first attempt at contrast injection was more successful 
under ultrasound than under fluoroscopy guidance; ul-
trasound-guided arthrography is also faster, less painful 
and does not expose patients to ionizing radiation (15).
In his study, Ji compared the effectiveness of ultra-
sound-guided anterior and posterior arthrography ap-
proaches. The study included 28 patients, which were 
randomized into anterior (13) and posterior (13) ap-
proach groups, while two patients also had, due to severe 
extravasation during the anterior approach, an arthrog-
raphy with the posterior approach. In both groups, the 
success rate was 100%. In the anterior approach group, 
two patients (15%) had mild and two had severe extrav-
asation, while there were no extravasation events in the 
posterior approach group; in total, 14% of patients had 
contrast extravasation. The study results confirmed the 
safety, effectiveness and relative painlessness of the ul-
trasound-guided MR arthrography using a posterior ap-
proach (17).
The study by Ng et al, which included 40 patients and 
compared fluoroscopy-guided and ultrasound-guided 
MR arthrography using the anterior approach, reached 
similar conclusions. There were 20 patients in each 
group. The results showed that ultrasound-guided MR 
arthrography was comparable to fluoroscopy-guided MR 
arthrography, but with the advantage that the patient and 
radiologist are not exposed to ionizing radiation (19).
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Legend: UMC LJ – University Medical Centre Ljubljana; USp – ultrasound-guided MR-arthrography using the posterior approach; 
USa – ultrasound-guided MR-arthrography using the anterior approach; FLa – fluoroscopy-guided MR-arthrography using the 
anterior approach.
USp UMC LJ USp (15) USa (15) FLa (15)
Procedure success rate 100% 100% 100% 100%
Average volume of standard contrast mixture injected 9.8 mL 18.6 mL 14.6 mL 14.5 mL
Extravasation 43.3% 52% 36% 68%
Procedure duration 8.8 min 9.3 min 9.9 min 17 min
Average pain score 3.6 2.7 1.6 3.9
Complications 7.5% (mild) 8% 0% 8%
Table 1: Parameters assessed and comparison with the study by Rutten et al. The first column contains the values from the 
study at the University Medical Centre Ljubljana, while the 2nd, 3rd and 4th columns contain the values from the study by 
Rutten et al (15,16).
Figure 1: Extravasation was assessed on a four-point scale: 0 – no extravasation (A), mild – along the needle tract (B), 
moderate – infiltration of the adjacent muscle fascia and muscles (C) and severe – reduced diagnostic value of the test (D). 
Adapted from Salapura V, et al, 2017 (16).
2.2 Experience at the Institute of Radiology, 
University Medical Centre Ljubljana
With the introduction of the new method at the Uni-
versity Medical Centre Ljubljana (UMC Ljubljana), the 
success of ultrasound-guided arthrography was evalu-
ated at the Institute of Radiology. Between April 2015 
and April 2016, 67 patients with shoulder joint instabil-
ity or rotator cuff injury were included in the study of 
ultrasound-guided MR arthrography using the posteri-
or approach. The purpose of the study was to evaluate 
the effectiveness and duration of intra-articular contrast 
agent injection, contrast extravasation volume and rota-
tor diagnosis accuracy after contrast extravasation. We 
recorded the number of attempts required for success-
ful contrast injection, which we defined as the need for 
needle repositioning after unsuccessful intra-articular 
insertion. We measured the injection duration and total 
procedure duration until the needle was properly posi-
tioned. In each patient, the volume of injected contrast 
was measured, procedural complications were noted 
and pain assessment was performed (16).
In our study, the first attempt at intra-articular con-
trast injection was successful in 86.6% of patients; in 
11.9%, we needed two attempts, three attempts were 
needed in only 1.5% of patients. A successful procedure 
was one where the contrast agent was injected into the 
joint, which means that in all 67 patients, we were suc-
cessful on the whole, including in our first attempt. The 
average duration of contrast injection was 8.8 minutes 
with an average pain score of 3.6. In 43.3% of patients, 
contrast extravasation occurred, of which 32.5% were 
mild, 8.9% moderate and 7.5% severe (Figure 1). Al-
though the proportion appears to be large, most were 
functionally completely insignificant extravasations that 
did not interfere with diagnostic procedures. Compared 
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to the anterior approach, the proportion of extravasa-
tions is slightly higher, but the posterior approach does 
not obscure the most frequently injured anterior shoul-
der joint structures, while the amount of contrast inject-
ed into the joint is still suitable for accurate diagnostic 
assessment (Table 1).
In 7.5% of patients, a mild vasovagal reaction oc-
curred, which all subsided after the patients layed down. 
No other complications were noted (16).
The study results have confirmed that ultrasound-guid-
ed MR arthrography using the posterior approach is a 
good alternative to fluoroscopy-guided arthrography, but 
with important advantages for patients (16).
3 Conclusion
MR arthrography is the method of choice for evalu-
ation of small intra-articular shoulder joint structures, 
which are most commonly injured in shoulder instability. 
In addition to the standard minimally invasive ar-
thrography technique, the ultrasound-guided shoulder 
joint contrast injection technique is now established, as 
the development of ultrasound technology has made sig-
nificant progress in the quality of high-frequency linear 
probes, which allow accurate display of small soft tissue 
structures. The main advantage of ultrasound-guided 
posterior approach arthrography is that it avoids the 
anterior structures that are most commonly injured in 
shoulder joint instability. At the same time, the method 
is safe and effective, as it allows examination of the joint 
before the introduction of contrast and tracking needle 
placement in real time; additionally, as iodine contrast is 
not required, the patient is not exposed to radiation.
Conflict of interest
None declared.