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Core set of unfavorable events of shoulder
arthroplasty: an international Delphi consensus
process
Laurent Audig
e, PhD
a,b,
*, Hans-Kaspar Schwyzer, MD
b
, Shoulder Arthroplasty Core
Event Set (SA CES) Consensus Panel, Holger Durchholz, MD
b,c
a
Research and Development, Schulthess Clinic, Z€
urich, Switzerland
b
Shoulder and Elbow Surgery, Schulthess Clinic, Z€
urich, Switzerland
c
Klinik Gut, St Moritz, Switzerland
Background: Shoulder arthroplasty (SA) complications require standardization of definitions and are not
limited to events leading to revision operations. We aimed to define an international consensus core set of
clinically relevant unfavorable events of SA to be documented in clinical routine practice and studies.
Methods: A Delphi exercise was implemented with an international panel of experienced shoulder sur-
geons selected by nomination through professional societies. On the basis of a systematic review of
terms and definitions and previous experience in establishing an arthroscopic rotator cuff repair core
set, an organized list of SA events was developed and reviewed by panel members. After each survey,
all comments and suggestions were considered to revise the proposed core set including local event groups,
along with definitions, specifications, and timing of occurrence. Consensus was reached with at least two-
thirds agreement.
Results: Two online surveys were required to reach consensus within a panel involving 96 surgeons. Be-
tween 88% and 100% agreement was achieved separately for local event groups including 3 intraoperative
(device, osteochondral, and soft tissue) and 9 postoperative event groups. Experts agreed on a documen-
tation period that ranged from 3 to 24 months after SA for 4 event groups (peripheral neurologic, vascular,
surgical-site infection, and superficial soft tissue) and that was lifelong until implant revision for other
groups (device, osteochondral, shoulder instability, pain, late hematogenous infection, and deep soft tissue).
Conclusion: A structured core set of local unfavorable events of SA was developed by international
consensus to support the standardization of SA safety reporting. Clinical application and scientific evalu-
ation are needed.
Level of evidence: Level V; Expert Opinion; Consensus Development
Ó2019 Published by Elsevier Inc on behalf of Journal of Shoulder and Elbow Surgery Board of
Trustees. This is an open access article under the CC BY-NC-ND license (http://creativecommons.o
rg/licenses/by-nc-nd/4.0/).
Keywords: Shoulder; arthroplasty; unfavorable events; complications; standardization; Delphi process;
core event set
Institutional review board approval was not required for this consensus
development project.
*Reprint requests: Laurent Audig
e, PhD, Research and
Development–Shoulder and Elbow Surgery, Schulthess Clinic, Lengghalde
2, CH-8008 Z€
urich, Switzerland.
E-mail address: laurent.audige@kws.ch (L. Audig
e).
J Shoulder Elbow Surg (2019) -,1–11
www.elsevier.com/locate/ymse
1058-2746/Ó2019 Published by Elsevier Inc. on behalf of Journal of Shoulder and Elbow Surgery Board of Trustees. This is an open access article under the
CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
https://doi.org/10.1016/j.jse.2019.07.021
The incidence of shoulder arthroplasty (SA) is
increasing.
11,22,24
Although SA is associated with rapid and
persistent recovery of shoulder function and quality of life
for most patients, some experience local complications that
may lead to revision surgery.
10,14,30,31
Among osteoarthritis
patients, 4% require revision after primary total SA at a
mean follow-up time of 3.3 years.
10
Monitoring implant
survival, as well as establishing the reasons for revision,
29
is essential to identify inadequate or suboptimal implants
or procedures.
9
High-quality registries permit the assessment of implant
survival. They also include relevant image-based, clinical,
and patient-reported outcome data with sufficient granu-
larity to allow in-depth and qualitative scientific evaluation
of various procedures for all patients regardless of whether
revision is necessary.
28
A recent international consensus
process led to the development of a so-called core outcome
set
8,15
for shoulder disorders,
25
which considers inner core
domains of pain, physical function and activities, global
perceived effect (personal assessment of recovery or degree
of improvement), and adverse events (AEs).
6
From the
consensus process, it was clear that clinically relevant AEs
may not always lead to SA revision but could potentially
harm affected patients and must be considered.
Valid and consistent reporting of AEs in SA is essential
to foster adequate decision-making processes, but much of
the quantitative information stems from reviews of pub-
lished data
4,5,7,16,23,38
and retrospective series that are
highly inconsistent.
20
Further reports of large administra-
tive databases
13,21,36
only include events that were not
defined by consensus and may not be considered unfavor-
able events relevant to surgeons and their patients.
Mandated registration of device failures with health au-
thorities more likely provides valid safety implant
data
33
yet also excludes further relevant events. There is a
clear need for consensus on which events should be docu-
mented according to outlined quality standards.
A core event set (CES) was recently developed for
arthroscopic rotator cuff repair (ARCR) as a hierarchical
and structured list of unfavorable events along with their
terms and definitions.
1
The aim of this project was to
extend the international consensus CES work for the
common orthopedic procedure of SA. We hypothesized that
by applying a Delphi process including a series of online
surveys, we could achieve consensus within a large panel of
experienced shoulder surgeons on a core set of local un-
favorable events applicable to any type of prosthesis to
support the standardization of SA safety reporting.
Materials and methods
General methodology
This study encompasses the development of a classification sys-
tem for clinically relevant unfavorable events of SA. We applied a
well-accepted methodologic process
37
for the development of the
SA CES, which was similar to that for ARCR.
1
A systematic
literature review was implemented comprising 495 original arti-
cles published between 2010 and 2014,
20
which gave rise to a total
of 1399 event terms grouped according to 8 of 9 previously
defined event groups: device, osteochondral, pain, surgical-site
infection, peripheral neurologic, vascular, superficial soft tissue,
and deep soft tissue.
1
Another group of terms related to impaired
function was also established to examine the possibility of using a
similar structured list. The majority of reported event definitions
in 21.4% of the reviewed articles were related to periprosthetic
radiolucency, as well as humeral or glenoid loosening. On the
basis of this review and the previously published ARCR CES, we
drafted an initial CES for SA.
We applied the modified Delphi technique
19
together with an
international panel of experienced shoulder surgeons to review the
proposed CES and reach consensus on appropriate modifications.
In this process, participants were also invited to provide input
regarding the development of a minimum set of parameters for
postoperative monitoring of asymptomatic SA patients.
12
With the
online electronic data capture system REDCap,
17
participants
were asked to complete 3 successive surveys after personal invi-
tation by e-mail, in which the CES was specifically addressed
during the first and last surveys. We sent 2 automatic e-mail re-
minders and made individual personal contact to minimize the
proportion of nonresponders. All participants remained unaware
of the identities of the other panel members. We served as the
adjudication committee and remained blinded to all respondent
identities when reviewing the responses and proposing changes to
the CES.
Nomination and selection of panel members
Our international expert panel included orthopedic surgeons and
shoulder specialists with recognized experience in SA. The 84
shoulder surgeon members of the ARCR CES Consensus Panel
were included and complemented by nominations from the
following societies or professional groups: International Shoulder
Arthroplasty Consortium
26
; International Society of Orthopedic
Centers member clinics; European Society for Surgery of the
Shoulder and the Elbow; Swiss Orthopaedics; German Associa-
tion for Shoulder and Elbow Surgery; British Elbow and Shoulder
Society; American Shoulder and Elbow Surgeons; Dutch Shoulder
and Elbow Society; Italian Society of Shoulder and Elbow Sur-
gery; steering committee of the Danish Shoulder Arthroplasty
Registry; Swedish Orthopaedic Association; and Shoulder and
Elbow Society of Australia. All nominated surgeons were invited
to participate in the first and second Delphi surveys. Only re-
spondents to 1 of these 2 surveys were invited to complete the
third and final survey. Members of the SA Consensus Panel
acknowledged in this work participated in at least 1 of the 2
surveys addressing the CES.
Development of initial core set and first online
survey
The initial CES draft proposal was submitted for review and
commentary by invited surgeons as part as the initial Delphi
survey (Supplementary Appendix S1). Participants were asked
about their level of experience in orthopedics and, more
2 L. Audig
e et al.
specifically, in performing SA, as well as their agreement on the
CES development concept. We asked open questions regarding the
suggestion to develop a set of imaging parameters for monitoring
asymptomatic patients. Participants were asked if they agreed on
the propositions made regarding the distinction between intra-
operative and postoperative events, as well as the appropriate term
definitions, specifications, and period of observation for each
event group. For certain event groups (device, osteochondral, pain,
peripheral neurologic, and deep soft tissue), alternative observa-
tion periods (eg, 12 months, 24 months, 5 years, 10 years, 15
years, and lifelong) were suggested. Open fields allowed partici-
pants to comment on any additions or corrections they believed
were necessary. Consensus definitions of rotator cuff tear and
shoulder stiffness that originated from the ARCR CES Delphi
process
1
dand remained unpublished, particularly for the defini-
tion of shoulder stiffnessdwere proposed.
Second and third online surveys
On the basis of initial responses, a second survey was prepared to
address only a core set of radiologic monitoring parameters, which
was undertaken in parallel with this work on an SA CES. Proposed
changes to the CES were presented for review, commentary, and
agreement within the third and final survey (Supplementary
Appendix S2). Intraoperative event groups were excluded from
this survey because their definitions and specifications were fully
agreed on in the first survey. Postoperative event definitions and
specifications were amended for all initially proposed event
groups; a ‘‘shoulder instability’’ event group was added as sug-
gested by a panel member. In making the amendments, event
specifications were tailored in line with the core set of radiologic
parameters to ensure that these parameters could be defined and
recorded in a similar manner regardless of whether the patient
reported symptoms (ie, included in the CES) or not (ie, an
observation independent of the CES).
Data analysis and final adjudication
Survey data were transferred to Intercooled Stata (version 14;
StataCorp, College Station, TX, USA) for standard descriptive
analyses. Consensus was achieved when agreement of at least two-
thirds of the respondents was reached. The required observation
period for specific event groups was proposed when at least two-
thirds of the panel members suggested the same or a shortened
period. All comments and suggestions made by panel members
were listed and reviewed. Final amendments and adjudication of
the CES were made by us for a few parameters to ensure simple,
uniform, and pragmatic implementation of the core set.
Results
Consensus panel
Of 182 nominated surgeons invited to participate in the first
survey, only 1 was excluded because this surgeon did not
perform SAs. A total of 90 participants (50%) responded
partly (n ¼17) or completely (n ¼73). The second survey
sent to the same surgeons was answered by 72 participants
(40%), including 64 who had responded to the first survey.
The third survey was sent to 98 surgeons, to which almost
three-quarters (n ¼73) responded. There were 96 members
who responded to either the first or third survey, with 83
reporting either having more than 5 years’ orthopedic sur-
gical experience and performing at least 20 SAs annually
(Table I). Of these members, 74 (76%) originated from
Europe (Germany, 14; Switzerland, 15; United Kingdom,
14; The Netherlands, 8; others, 23), with 12 from North
America (United States, 11; Canada, 1) and 10 from else-
where (Chile, 2; Brazil, 2; Israel, 1; Australia, 5).
Initial survey
The development framework for the CES was highly sup-
ported with 99% agreement (89 of 90) among the first survey
participants. Of respondents, 89% (72 of 81) supported a
clear distinction between intraoperative and postoperative
events. In addition, consensus was reached with 93%
agreement (71 of 76) to organize intraoperative events into 3
distinct event groups (device, osteochondral, or soft tissue)
with specific consideration for the field of SA (Table II).
Respondents were rather (44%) or definitively (47%) in
agreement to adopt a structure comprising 8 event groups and
definitions gained from the ARCR CES with rotator cuff
events being considered within the deep soft-tissue event
group (implant [device], osteochondral, persisting or wors-
ening pain, peripheral neurologic, vascular, surgical-site
infection, superficial soft tissue, or deep soft tissue). Per-
centages of agreement for each event group definition and
specification ranged from 89% to 99%. Nevertheless,
numerous comments and suggestions were made, including
the option to add a separate shoulder instability event group
(Supplementary Appendix S3); this event group would
comprise those relevant events that do not fit as a new spec-
ification within any of the previously defined event groups.
Final survey
As a result of this last process, the shoulder instability event
group was added. The event group of surgical-site infection
Table I Skill of clinician consensus panel
Average annual SAs*Years of experience, n
y
Total, n
1-5 6-10 11-20 >20
1-20 d45 312
21-50 1 6 14 15 36
51-100 d316 1534
>100 d17 614
Total 1 14 42 39 96
SA, shoulder arthroplasty.
*
Panelists were asked, ‘‘On average, how many SAs do you perform
annually?’’
y
Panelists were asked, ‘‘How many years of surgical experience do
you have in orthopedics?’’
Unfavorable event core set of SA 3
was renamed the infection event group to incorporate late
hematogenous infections in the core set. The adjustments of
postoperative event terms and definitions organized into
9 groups were approved with 88% to 100% agreement
(Table III). The period of documentation ranged from 3 to 24
months after SA for 4 event groups and subgroups (periph eral
neurologic, vascular, surgical-site infection, or superficial
soft tissue) and was lifelong until implant revision for the
following: device, osteochondral, shoulder instability, pain,
late hematogenous infection, and deep soft tissue.
Device events included radiolucency around the implant
and implant loosening, as well as implant migration,
breakage, disassembly, and malpositioning (Table III).
Specific osteochondral events were listed as bone formation
or resorption, fracture around the implant, and the presence
of loose bodies. Several definitions were formulated and
agreed on in the context of radiologic SA monitoring,
particularly regarding subluxation and dislocation in the
shoulder instability event group; dynamic instability was
also considered in the CES. Persisting or worsening pain
events were similar to those outlined by the ARCR CES
and defined as occurring at night or during the day while at
rest or during everyday activities. Peripheral neurologic
events were reorganized by distinguishing sensory and/or
motor disturbance from autonomic disturbance (complex
regional pain syndrome). Vascular events included hema-
toma requiring evacuation, as well as thrombosis and
ischemia of the involved extremity. Periprosthetic late he-
matogenous infections considered for lifelong observation
in SA until implant revision were added to the CES, along
with the surgical-site infections, in a global infection event
group. Superficial soft-tissue events included early events
over a period of 30 days and late hypertrophic scar and
keloid events over a period of 6 months. Finally, the deep
soft-tissue event group was extended to include metallosis
and rotator cuff events; 94% of respondents (67 of 71)
approved the proposed consensus definition of rotator cuff
tear as a loss of tendon integrity with Sugaya classifica-
tion
34
type IV or V diagnosed by appropriate diagnostic
imaging including arthrographic computed tomography and
ultrasound examination (Table IV). The consensus defini-
tion of shoulder stiffness was also approved with the
following consideration: Motion restriction in passive
external rotation in 0of abduction was defined for
anatomic SA only as glenohumeral motion no more than
50% of the contralateral-side value. In addition, the
observation time frame for stiffness following SA was
extended to 12 months.
Discussion
This project focused on the development of a consensus
core set of unfavorable local events for SA. We used a
modified Delphi process and reached widespread consensus
after only 2 online surveys with between 88% and 100%
agreement for specific event groups within an international
panel of 96 experienced shoulder surgeons. The period of
Table II Definitions and specifications of intraoperative event groups*in core set
Event group Definition and specification
Device events Events affecting any component of the implanted device or material or the instrumentation
used for their implantation
Instrument problem (breakage, failure)
Implant (breakage, malpositioning, separation)
Cementation problems
Osteochondral events Events affecting the osteochondral tissue of the proximal humerus, clavicle, and/or scapula
Articular cartilage damage
Fracture
y
Humeral metaphyseal (above the surgical neck)
Humeral diaphyseal
Scapula
Soft-tissue events Events involving only the soft tissue in the treated shoulder
Skin, muscle, tendon, joint capsule, ligament, labrum
Blood vessels (bleeding): bleeding at the surgical site that requires additional intervention
or leads to a stop of the operation
Nerves: recognized damage of a neurologic structure that needs additional surgical
intervention
z
*
Intraoperative events were organized into 3 distinct event groups as previously presented
1
and adapted to focus on the field of shoulder arthroplasty.
Adaptations are italicized. Consensus was already reached for these definitions and specifications with 93% agreement (71 of 76 participants) achieved
during the first Delphi survey.
y
Fracture includes hairline fracture.
z
A standard list of potentially affected nerves is only presented for postoperative neurologic events.
4 L. Audig
e et al.
Table III Definitions and specifications of postoperative event groups*in core set
Event group Definitions and specifications Period Agreement, % (n)
Implant
(device)
Events affecting the implanted device(s) (prosthesis) that is (are)
shown on adequate postoperative imaging (eg, radiographs,
ultrasound, CT) and associated with clinical symptoms
Migration (subsidence, tilt, shift): noticeable change in the
position of an implant component relative to the bone to which it
is supposedly fixed
Radiolucency around the implant or implant loosening
Wear of the implant articular surfaces: damage, erosion or loss of
the articular surface material over time, which is identified by
reduction of joint space observed on serial plain radiographs
Breakage
Disassembly: noticeable change in the relative position of the
various parts of an implant humeral or glenoid component
Malpositioning
y
: implant not in its expected position
Lifelong until
implant revision
100 (64 of 64)
Osteochondral Events affecting the osteochondral tissue of the proximal humerus,
clavicle, and/or scapula
Bone formation or resorption (including scapular notching in
reverse shoulder arthroplasty, osteochondral erosion in
hemiarthroplasty, and bone cyst)
Fracture around the implant
Loose body
Lifelong until
implant revision
92 (59 of 64)
Persisting or
worsening pain
Shoulder pain reported by the patient that is not associated with
another identified local event (idiopathic) and is either
persisting (compared with preoperative status) beyond 6
mo postoperatively or worsening any time postoperatively
Night pain: shoulder pain that awakens the patient at night or
interferes with sleep
Daily pain while at rest
Daily pain during everyday activities (household, work, sport,
leisure, and so on)
Lifelong until
implant revision
95 (62 of 65)
Shoulder
instability
Symptomatic shoulder associated with loss of alignment of the
articulating surface of the humeral component with the
articulating surface of its joint partner
Subluxation: non–arm position–dependent eccentric misalignment
with residual contact
Dislocation: non–arm position–dependent complete loss of contact
of the articulating surfaces
Dynamic instability: arm position–dependent loss of contact of the
articulating surfaces apparent on physical examination and/or
visible on functional radiographs (horizontal flexion/extension
view in 90of abduction and true AP view in 60of abduction)
The direction of instability is noted from clinical examination as well
as the AP view (superior/inferior) and from the axillary view or Y-
view (anterior/posterior)
Lifelong until
implant revision
91 (59 of 65)
Peripheral
neurologic
Events resulting from peripheral neurologic injury at the surgical site,
which was not present prior to surgery (including worsening of
preoperatively known neurologic lesion) and which is associated
with sensory and/or motor and/or autonomic disturbance
Sensory and/or motor disturbance: affected nerve(s)
Cervical or brachial plexus
Branch neuropathy (suprascapular, musculocutaneous, median,
ulnar, radial, axillary, dorsal scapular, long thoracic, spinal
accessory, thoracodorsal, cutaneous nerves of arm and
forearm)
Autonomic disturbance: CRPS
Neurologic injury may be classified by a neurologist according to
3 mo 91 (58 of 64)
(continued on next page)
Unfavorable event core set of SA 5
documentation after SA was limited to between 3 and 24
months for only 4 event groups and should otherwise
remain a lifelong process. There is a lack of general
agreement in the literature about how ‘‘consensus’’ should
be defined, although reaching a threshold percentage for
certain responses is most often applied.
19
Our decision to
consider a threshold of two-thirds agreement was deter-
mined a priori to include relevant items that should not be
excluded from further evaluation in field testing; the
reporting of actual percentages of agreement well above
80% shows the robustness of our achievement.
The development framework for this project was highly
supported among participants of the first survey. The fact
that the CES achieved large consensus after only 2 survey
rounds shows that our concept appeals to the vast majority
of clinicians. Adaptation of the previous ARCR CES was
Table III Definitions and specifications of postoperative event groups*in core set (continued)
Event group Definitions and specifications Period Agreement, % (n)
Seddon
32
(ie, neurapraxia, axonotmesis, or neurotmesis) and/or
Birch
3
(degenerative, short conduction block, prolonged condition
block)
Vascular Events involving laceration, avulsion, contusion, puncture, or crush
injury to an artery, vein, or microvascularity at the surgical site
Hematoma that requires evacuation by needle puncture or surgery
Superficial and deep thrombosis at the involved extremity
Ischemia of the involved extremity that requires additional
intervention
30 d 91 (59 of 65)
Infections SSI: definition and specifications adapted from the 2008 Centers for
Disease Control and Prevention definition
18
Superficial incisional SSIs: infections involving only the skin and
subcutaneous tissue of the incision: early (<3 mo)
Deep SSIs (incisional and organ or space): infections involving any
part of the anatomy (eg, fascia, muscle, organs, and spaces)
other than the skin and subcutaneous tissue of the incision: early
(<3 mo) and low grade (3-24 mo)
35
3-24 mo 88 (57 of 65)
Late hematogenous infections: periprosthetic infections defined
according to international consensus
27
>24 mo until
implant revision
Superficial
soft tissue
Events affecting the superficial soft tissues (ie, skin and
subcutaneous tissue) at and around the surgical site and/or
wound that do not affect deep soft tissues (ie, fascia, muscle, or
articular capsule) and that require additional treatment
Early events within 30 d: edema, emphysema, burn, delayed wound
healing, hypersensitivity reaction, skin necrosis, and skin bulla
Late events within the first 6 mo: hypertrophic scar and keloid
(except if known history of development)
30 d to 6 mo 97 (62 of 64)
Deep soft
tissue
Events affecting the deep soft tissues (ie, fascia, muscle, or articular
capsule), except infections
Affecting the subacromial/subcoracoid space (impingement,
adhesion, and so on)
Affecting the biceps
Affecting the capsule (shoulder stiffness,
z
metallosis)
Affecting the rotator cuff
z
Affecting the deltoid
Lifelong until
implant revision
94 (59 of 63)
CT, computed tomography; AP, anteroposterior; CRPS, complex regional pain syndrome; SSI, surgical-site infection.
*
Postoperative events were organized into distinct event groups as previously presented
1
and adapted for the field of shoulder arthroplasty. The rotator
cuff event group was moved into the deep soft-tissue event group. A new event group related to shoulder instability was included. The infection event
group includes late hematogenous infections. Most specifications within the implant, osteochondral, and peripheral neurologic event groups were
adapted.
y
A malpositioned implant may result from intraoperative malpositioning and/or postoperative implant displacement. The time of occurrence may be
determined by immediate postoperative assessment of the implant position.
z
Consensus definitions of shoulder stiffness and rotator cuff tear were also agreed on, together with the deep soft-tissue event group, as presented in
Table IV.
6 L. Audig
e et al.
fairly straightforward and required minimal changes, which
further demonstrates the relevance of the current proposal
for SA, as well as any future CES development for other
indications or treatments in orthopedics.
Previous reports on complications after SA were largely
based on retrospective case series, and about one-fifth of
examined articles in our previous literature review
20
were
narrative reviews. Without international consensus, the au-
thors of these reports were left to judge which events were
most relevant to them or their patients. Other reports using
large administrative databases
13,21,33,36
targeted specific
events that were not primarily documented for assessing
comprehensively unfavorable events and patient safety in
SA. Therefore, our CES provides a more specific and
comprehensive system for events localized to the affected
shoulder; this system can then be complemented by a more
generic system for events affecting other body
structures.
2
The CES should be considered the minimum
documentation requirement for assessing AEs in the context
of clinical studies.
6
We believe the CES will also allow for a
more in-depth and transparent assessment of patient out-
comes in clinical registries. The use of a standardized
structure to record these events should facilitate the ability
to combine data from multiple assessment sites as well as
compare outcomes between implants, clinical settings, and
surgeons. Consistent with the need to document long-term
implant survival in SA registries, all events that may lead
to the deterioration of shoulder function and implant revi-
sion should be documented over the patient’s lifetime.
Our proposed hierarchical system organized into event
groups offers flexibility in its application and development so
that detailed specifications can be added to the CES at any
time point. Although definitions of rotator cuff tear and
shoulder stiffness were approved in the context of SA, we
foresee that further development and adjustment will be
required after a period of application and evaluation in real-
life settings. It should be noted that the CES from this project
focuses on symptomatic events that may trigger additional
examinations or treatments for affected patients; the events
may be captured passively when patients consult the surgeon
of their own accord, as well as actively by asking patients
about the occurrence of unfavorable events at regular post-
operative intervals. We recommend the documentation of
symptomatic events in parallel with a proposed systematic
SA monitoring schedule in all patients.
The strengths and limitations of this consensus project are
similar to those previously outlined.
1
We applied the term
‘‘unfavorable event’’ because the term ‘‘surgical complica-
tion’’remained undefined. Comprehensive documentation in
clinical registries and studies should outline how recorded
events relate to SA, harm patients, or influence outcomes. We
used cost-effective methodologic standards for consensus
development using a modified Delphi exercise. Participation
was very high within the large international panel of expe-
rienced shoulder surgeons, with a 74% response rate for the
final survey; although the consensus reflects their opinions
well, the perspective of SA patients remains to be captured
during the evaluation phase of the current proposal. Only 2
surveys were required to complete the CES, partly because
our initial proposal was based on adapting the existing CES in
ARCR. We believe that there was no justification to start the
development process without consideration of the previous
consensus and that there is value in harmonizing the
Table IV Consensus definitions of rotator cuff tear and
shoulder stiffness in shoulder arthroplasty
Event Definition*
Rotator cuff tear
y
A rotator cuff event affects the
anatomic and functional integrity of
the rotator cuff including one of the
following muscles and tendons:
subscapularis, supraspinatus,
infraspinatus, or teres minor
A rotator cuff tear (imaging definition)
is a loss of rotator cuff tendon
integrity (full-thickness tear defined
as either type IV or V based on the
Sugaya classification
34
and
diagnosed on appropriate imaging
(arthro-CT, ultrasound)
Shoulder stiffness
z
Postoperative restriction in passive
shoulder motion diagnosed in 2
of the motion planes of flexion,
abduction, and external fixation
in 0of abduction
Motion restriction is assessed
separately for each plane according
to the following criteria:
Flexion: total motion 90or
glenohumeral motion (fixed scapula)
80
Abduction: total motion 80or
glenohumeral motion (fixed scapula)
60
External rotation in 0of abduction:
glenohumeral (fixed scapula) motion
20(or, for anatomic shoulder
arthroplasty only, no more than 50%
of the contralateral-side value)
For the core set, only shoulder stiffness
occurring within 12 mo after shoulder
arthroplasty is considered
arthro-CT, arthrographic computed tomography.
*
These definitions were agreed on by the consensus panel together
with the deep soft-tissue event group, as described in Table III.
y
This definition was adapted from a previous proposal
1
with 1
change highlighted in italics.
z
This definition was previously developed by members of the
Arthroscopic Rotator Cuff Repair Core Event Set Consensus Group
1
and
adapted for the context of shoulder arthroplasty.
12
Modifications are
shown in italics. The observation time frame of 6 months following
arthroscopic rotator cuff repair was extended to 12 months for
shoulder arthroplasty.
Unfavorable event core set of SA 7
framework and structure of the approved systems for doc-
umenting unfavorable events across various indications or
treatments in shoulder surgery. Finally, our own judgment
was applied to assess individual opinions and ensure appli-
cability of the final CES in practice.
The present core set has been included in a standard
electronic complication form for systematic documentation
as part of our local SA registry using a REDCap
database.
17
The use of branching logic facilitates the
documentation and evaluation of any unfavorable events in
the defined structure. To foster availability and wide uni-
form field application, we created an electronic and paper
form for our ‘‘SA core event set 1.0’’ to be used in any
documentation system, as well as clinical studies
(Supplementary Appendix S4). Some unfavorable events
may occur simultaneously in any patient, which can result
in an overall assessment and management process. We
suggest that only the leading event should be recorded,
although contrary to Somerson et al,
33
we did not predefine
a hierarchy of events for anatomic and reverse SA. Treating
surgeons should rely on their own professional judgment.
Finally, our paper form remains limited with respect to the
space offered to adequately document the events. Our
electronic form, on the other hand, offers more detailed
options for recording, for example, grading of radiolucency,
scapular notching, and fracture classification, which are
addressed in the context of a parallel project on radiologic
monitoring.
12
This information can be captured in the
descriptive field of the paper form if not recorded
electronically.
Conclusion
This international Delphi consensus process contributes
to the standardization of reporting unfavorable events of
SA for safety evaluation. The proposed SA CES in its
first version should be applied in practice and assessed
regarding its comprehensiveness and relevance for
patients.
Acknowledgments
The authors greatly thank the participants of the Delphi
consensus process recognized in the SA CES Consensus
Panel author list. The authors would also like to
acknowledge the support of Dr. Melissa Wilhelmi,
medical writer at the Schulthess Clinic, Z€
urich,
Switzerland, for manuscript proofreading and assisting
with the submission process.
The SA CES Consensus Panel members are as fol-
lows: Ville
€
A€
arimaa, MD, Turku University Hospital,
Turku, Finland; Tjarco D. Alta, MD, PhD, Spaarne
Gasthuis, Haarlem/Hoofddorp, The Netherlands; Marcus
Vinicius Amaral, MD, MSc, Instituto Nacional de
Traumatologia e Ortopedia, Rio de Janeiro, Brazil;
Alison Armstrong, MD, University Hospitals of
Leicester NHS Trust, Leicester, United Kingdom; Steve
Bale, MD, Wrightington Hospital, Wrightington, United
Kingdom; Shaul Beyth, MD, PhD, Hadassah Medical
Center, Jerusalem, Israel; Andreas Bischof, MD, Berit
Klinik, Speicher, Switzerland; Desmond J. Bokor, MD,
Faculty of Medicine & Health Sciences, Macquarie
University, Sydney, NSW, Australia; Mario Borroni,
MD, Humanitas Clinical and Research Center IRCCS,
Milan, Italy; Stig Brorson, MD, PhD, DMSc, Zealand
University Hospital, University of Copenhagen, Copen-
hagen, Denmark; Peter Brownson, DM, FRCS(Ed),
FRCS(Tr&Orth), Royal Liverpool Hospital, Liverpool,
United Kingdom; Stefan Buchmann, MD,
Orthop€
adisches Fachzentrum Weilheim, Weilheim,
Germany; Eduard Buess, MD, Shouldercare Clinic,
Berne, Switzerland; Benjamin Cass, MD, Royal North
Shore Hospital, Sydney, NSW, Australia; Cormac Kelly,
MD, Robert Jones and Agnes Hunt Orthopaedic Hos-
pital, Oswestry, United Kingdom; Vincenzo De Cupis,
MD, ICOT, Latina, Italy; Philippe Debeer, MD, PhD,
University Hospitals Leuven, Leuven, Belgium; Mark T.
Dillon, MD, The Permanente Medical Group, Kaiser
Permanente, Sacramento, CA, USA; Holger Durchholz,
MD, Klinik Gut, St Moritz, Switzerland; Anders Eke-
lund, MD, PhD, Department of Orthopaedics, Capio St
G€
orans Hospital, Stockholm, Sweden; Mikael Etzner,
MD, Department of Orthopaedics Sjukhuset i Varberg,
Varberg, Sweden; Matthias Flury, MD, Zentrum f€
ur
Orthop€
adie & Neurochirurgie In-Motion, Wallisellen,
Switzerland; Mark Frankle, MD, Florida Orthopaedic
Institute, Temple Terrace, FL, USA; John Geoghegan,
MD, Nottingham University Hospitals, Nottingham,
United Kingdom; Harry Georgousis, MD, PhD, St Jo-
seph Hospital, KKRH–Contillia Group, Essen, Ger-
many; Ariane Gerber-Popp, MD, Kantonsspital
Baselland, Basel, Switzerland; K
aroly Guly
as, MD,
P
eterfy S
andor Hospital and Trauma Center, Budapest,
Hungary; Patrick Henry, MD, University of Toronto,
Toronto, ON, Canada; Ralph Hertel, MD, Lindenhof-
spital, Berne, Switzerland; Philipp Heuberer, MD,
Krankenhaus der Barmherzigen Schwestern Wien,
Vienna, Austria; Philip Holland, MD, The James Cook
University Hospital, Middlesbrough, United Kingdom;
Nicolas Holzer, MD, H^
opitaux Universitaires de Gen-
eve, Geneva, Switzerland; Greg Hoy, MD, Melbourne
Orthopaedic Group, Monash University, Melbourne,
VIC, Australia; Andreas B. Imhoff, MD, Hospital
Rechts der Isar University of Munich, Munich, Ger-
many; Hans Viggo Johannsen, MD, Aarhus University,
Aarhus, Denmark; Matthew Kent, MD, Royal Liverpool
Hospital, Liverpool, United Kingdom; Georges Kohut,
MD, Clinique G
en
erale Ste-Anne, Fribourg,
8 L. Audig
e et al.
Switzerland; Alexandre L€
adermann, MD, University of
Geneva, Geneva, Switzerland; Simon Lambert, MD,
University College London Hospital, London, United
Kingdom; Ulrich Lanz, MD, Sportorthop€
adie Zentrum,
Vienna, Austria; Evan Lederman, MD, The Orthopedic
Clinic Association (TOCA), Phoenix, AZ, USA; Lars
Lehmann, MD, St Vincentius-Kliniken, Karlsruhe,
Germany; Jan Leuzinger, MD, Etzelclinic, Pf€
affikon,
Switzerland; Sven Lichtenberg, MD, ATOS Klinik
Heidelberg, Heidelberg, Germany; Jonathan Livesey,
MD, Scarborough Hospital, Scarborough, United
Kingdom; Markus Loew, MD, PhD, ATOS–Clinic Hei-
delberg, Heidelberg, Germany; Olaf Lorbach, MD, PhD,
Saarland University, Homburg, Germany; Kirsten
Lundgreen, MD, PhD, Lovisenberg Diaconal Hospital,
Oslo, Norway; Dirk Maier, MD, Medical
Center–University of Freiburg, Freiburg, Germany;
Frank Martetschl€
ager, MD, ATOS Clinic Munich,
Munich, Germany; Nicholas Matis, MD, Paracelsus
Medical University Salzburg, Salzburg, Austria; Saurabh
Sagar Mehta, FRCS(Tr&Orth), University Hospitals of
North Midlands, Stoke on Trent, United Kingdom;
Dominik Meyer, MD, Balgrist University Hospital,
Z€
urich, Switzerland; Peter J. Millett, MD, Steadman
Clinic, Vail, CO, USA; Philipp Moroder, MD, Center for
Musculoskeletal Surgery, Charit
e Universit€
atsmedizin,
Berlin, Germany; Geraldo Motta, MD, MSc, Instituto
Nacional de Traumatologia e Ortopedia, Rio de Janeiro,
Brazil; Andreas Mueller, MD, University Hospital of
Basel, Basel, Switzerland; Ronald A. Navarro, MD,
Southern California Permanente Medical Group, Kaiser
Permanente, Rolling Hills, CA, USA; Wolfgang Nebe-
lung, MD, Marienkrankenhaus D€
usseldorf-Kai-
serswerth, D€
usseldorf, Germany; J€
org Neumann, MD,
HELIOS ENDO-Klinik, Hamburg, Germany; Richard
Page, MD, School of Medicine Deakin University,
Geelong, VIC, Australia; Paolo Paladini, MD, U. O.
Chirurgia della Spalla, Ospedale Cervesi, AUSL
Romagna, Cattolica, Italy; Vipul Patel, FRCS(Orth),
South West London Elective Orthopaedic Centre,
Epsom, United Kingdom; Ludo Penning, MD, PhD,
MSc, Sint Maartenskliniek, Nijmegen, The Netherlands;
Dirk Petr
e, MD, Sint-Jozefskliniek, Izegem, Belgium;
Dario Petriccioli, MD, Istituto Clinico Sant’ Anna,
Brescia, Italy; Pol Huijsmans, MD, Bergman Clinics,
Rijswijk, The Netherlands; Amar Rangan, MD, The
James Cook University Hospital, Middlesbrough, United
Kingdom; Jonny Rees, MD, University of Oxford, Ox-
ford, United Kingdom; Felipe Reinares, MD, Clinica
Alemana, Santiago, Chile; Herbert Resch, MD, Para-
celsus Medical University Salzburg, Salzburg, Austria;
Anthony A. Romeo, MD, Rothman Orthopaedic Insti-
tute, New York, NY, USA; Claudio Rosso, MD, MSc,
ARTHRO Medics Corp and University of Basel, Basel,
Switzerland; Roberto Rotini, MD, Istituto Ortopedico
Rizzoli, Bologna, Italy; Miguel A. Ruiz-Iban, MD, PhD,
Hospital Universitario Ram
on y Cajal, Madrid, Spain;
Bj€
orn Salomonsson, MD, PhD, Karolinska Institutet
Danderyds Sjukhus AB, Stockholm, Sweden; Michael
Sandow, FRACS, Wakefield Orthopaedic Clinic, Ade-
laide, SA, Australia; Felix H. Savoie, MD, Department
of Orthopaedic Surgery, Tulane University, New
Orleans, LA, USA; Johan Scheer, MD, Link€
oping Uni-
versity, Link€
oping, Sweden; Markus Scheibel, MD,
Schulthess Klinik, Z€
urich, Switzerland; Hans-Kaspar
Schwyzer, MD, Schulthess Klinik, Z€
urich,
Switzerland; Jose Francisco Soza Rex, MD, Pontificia
Universidad Cat
olica de Chile, Santiago, Chile; John
Sperling, MD, MBA, Mayo Clinic, Rochester, MN,
USA; Christoph Spormann, MD, Endoclinic Z€
urich,
Z€
urich, Switzerland; Mark Tauber, MD, ATOS Clinic
Munich, Munich, Germany; Theis Thillemann, MD,
PhD, Aarhus University Hospital, Aarhus, Denmark;
Thomas (Quin) Throckmorton, MD, University of
Tennessee-Campbell Clinic, Memphis, TN, USA; Tim
Peckham, MD, Basildon University Hospital, Basildon,
United Kingdom; Felipe Toro, MD, Cl
ınica Alemana,
Santiago, Chile; Marco van der Pluijm, MD, Sint
Maartenskliniek, Nijmegen, Gelderland, The
Netherlands; Peer van der Zwaal, MD, PhD, Haaglanden
Medical Center, The Hague, The Netherlands; Derek
F.P. van Deurzen, MD, Onze Lieve Vrouwe Gasthuis,
Amsterdam, The Netherlands; Arthur van Noort, MD,
PhD, Spaarne Hospital, Hoofddorp, The Netherlands;
Cornelis Visser, MD, PhD, Alrijne Hospital, Leiden, The
Netherlands; Markus Wambacher, MD, Medical Uni-
versity Innsbruck, Innsbruck, Austria; Stephen C.
Weber, MD, Johns Hopkins School of Medicine, Silver
Spring, MD, USA; and Gerald Williams, MD, Rothman
Orthopaedics, Bryn Mawr, PA, USA.
Disclaimer
Support for this research was provided by the Schulthess
Clinic.
The authors, their immediate families, and any
research foundations with which they are affiliated have
not received any financial payments or other benefits from
any commercial entity related to the subject of this article.
Supplementary data
Supplementary data to this article can be found online at
https://doi.org/10.1016/j.jse.2019.07.021.
Unfavorable event core set of SA 9
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Unfavorable event core set of SA 11
