Eur J Orthop Surg Traumatol (2018) 28:415–421
ORIGINAL ARTICLE • ELBOW - IMAGING
The smartphone inclinometer: A new tool to determine elbow
range of motion?
· Abdulaziz Aljurayyan
· Fahad H. Abduljabbar
· Patrick Goetti
· Fiona Houghton
· Edward J. Harvey
Dominique M. Rouleau
Received: 23 May 2017 / Accepted: 8 October 2017 / Published online: 19 October 2017
© Springer-Verlag France SAS 2017
(mean of 6.4° ± 1.0°), and EST underestimated it (mean
of − 7.9° ± 1.1°). For extension, the mean diﬀerence was
2.8° ± 0.7° for EST and − 26.8° ± 3.1° for XR. The APP
method did not signiﬁcantly diﬀer from GON. Supination
accuracy was greater with EST (2.7° ± 1.7°) than with APP
(5.9° ± 1.9°). There was no diﬀerence for pronation meas-
urement with both EST and APP.
Conclusions This study is the ﬁrst comparing four meas-
urement techniques of elbow ROM. Our results showed that
EST was only accurate for forearm rotation. The XR scored
the best for ﬂexion but is less reliable for extension. Sur-
prisingly, compared to GON, APP did not correlate as we
expected for ﬂexion and supination, but the other methods
were also inaccurate. We found APP to be very useful to
measure complete arc of motion (diﬀerence between maxi-
mal ﬂexion and maximal extension).
Level of Evidence III, Retrospective review of a prospec-
tive cohort of elbow fracture patients: Diagnostic Study.
Keywords Elbow range of motion · Smartphone
application · Inclinometer · Goniometer · Accuracy · X-ray
Measuring joint range of motion (ROM)  is an essential
component of evaluating orthopedic patients. The ROM
measurement is used on a daily basis in diﬀerent settings
including the outpatient clinic and the operating room. Accu-
rate measurements are needed not only for diagnostic pur-
poses and patient follow-up, but also to validate outcomes
for clinical research. Many surgeons use this measurement
as a colloquial replacement for patient-reported outcomes
that are more diﬃcult to gather in most clinical situations.
Background There are easily accessible tools on smart-
phones (APP) for measuring elbow range of motion (ROM).
The purpose of this study is to evaluate the validity of a par-
ticular APP in determining elbow ROM in comparison with
the commonly used goniometer (GON), surgeon estimation
of range (EST) and measurement on X-ray (XR).
Methods The study included 20 patients (40 elbows).
Flexion, extension, pronation and supination were meas-
ured using three diﬀerent methods: EST, GON and APP.
Radiographic measurements were taken using the average
humeral diaphysis axis and dorsal midthird of ulna in ﬂexion
Results The accuracy of the three different methods
has been compared to GON using statistical analysis
(ANOVA and paired samples test). There was no statisti-
cally signiﬁcant diﬀerence for XR ﬂexion measurement
(mean of 2.8° ± 1.5°). The APP overestimated flexion
* Dominique M. Rouleau
Department of Orthopedic and Trauma Surgery, Lausanne
University Hospital, Lausanne, Switzerland
Department of Orthopedic Surgery, King Saud University,
Riyadh, Saudi Arabia
Department of Orthopedic Surgery, King Abdulaziz
University, Jeddah, Saudi Arabia
Department of Orthopedic Surgery, McGill University Health
Centre, Montreal, Canada
Faculty of Medicine, Imperial College London,
London SW7 2AZ, UK
Department of Orthopedic Surgery, Hôpital du Sacré-Cœur
de Montréal, C2095-5400 Boul. Gouin Ouest, Montreal,
QC H4J 1C5, Canada