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Emerging Issues

Reliability of a New Application for Smartphones(DrGoniometer) for Elbow Angle Measurement

Giorgio Ferriero, MD, Francesco Sartorio, PT, Calogero Foti, MD,Diego Primavera, OT, Elisa Brigatti, MD, Stefano Vercelli, MSc

 Joint goniometry is a common mode of clinical assessment used in many disciplines, in

particular rehabilitation [1-3]. One way to perform joint goniometry is through the use of 

computer-aided joint measurements from digital photographs [4-8]. This method entails a

complex procedure to obtain the range of motion (ROM) value,which consists of thepicture

being manipulated upon by dedicated software once it has been downloaded from the

camera to a computer.

Recently, a new iPhone (Apple Inc, Cupertino, CA)-based application (app) functioning as a

virtual goniometer, DrGoniometer (DrG; C.D.M. srl, Milano, Italy), has been developed to

provide a simpler, faster measurement of limb joint mobility (Figure 1). Measurements with the

DrG app are obtained by positioning a virtual goniometer, visible on the smartphone screen, on

a picture previously taken by the mobile camera. The software creates an easily retrievable

patient database. After selecting the patient, the clinician chooses the desired joint from a list and

the respective motion to measure (eg, flexion, extension), then simply takes a photo of the limb,

saves it, measures the joint angle, and observes the value. For research purposes, it is possible to

blind the rater to the angular value. Notes can be added to each picture. The measurements and

pictures are stored in the smartphone database for further analysis, if required. All data can be

easily downloaded to a computer to obtain direct written reports.

 We assessed the reliability (intra- and interrater correlation and agreements analysis) of 

DrG in comparison with a small plastic universal goniometer (UG) [1] for elbow ROM

measurement [9]. Twenty-eight pictures of elbows of healthy subjects, measured by UG at

different angles, were assessed with DrG by 7 raters, selected as expert clinicians and

working in 2 different facilities. Measurements were repeated after 1 week. Each picture was judged adequate, that is, without evident perspective error. Raters were blinded to all joint

angles values. The 392 measurements were used to assess: the intraclass correlation

coefficient (ICC) for intrarater and interrater reliability [9]; and the agreement between the

DrG and UG, considering 10° as the acceptable interval (width) within which 95% of 

differences between measurements by the DrG and UG are expected to lie (limits of 

agreement, LoAϭ –5°, ϩ5°) [10,11].

The results showed high intra- and interrater correlation (ICC ϭ 0.998, 95%

confidence interval 0.998-0.999, and ICC ϭ 0.998, 95% confidence interval 0.996-

0.999, respectively). The width of 95% LoA between DrG and UG was equal to 10.26°

(LoA ϭ ϩ4.51°, Ϫ5.75°).

In a 1985 report, Fish and Wingate [2] assessed the accuracy of elbow goniometry by

comparing a manual goniometer with (conventional) photographic measurements. Theyfound that the accuracy of elbow angle measurement via photography was greater than via

the standard goniometer. The authors explained the difference by stating that the precision

of the photographic method was dependent on the use of landmarks. However, the use of 

landmarks in everyday practice is uncommon, which is why we preferred not to place any

label on the limb to be measured [12].

More recently, Hoffmann et al [13] compared the UG measurement of an upper limb

with that obtained by dedicated software that analyzed the still pictures of video images of 

the patients. Results showed that the investigators’ remote measurement method also had a

high level of intra- and interrater reliability for elbow goniometry (ICCϾ 0.97) and a width

of 95% LoA within 9.2°. DrG has shown a similar reliability to these photographic-based

G.F. Unit of Occupational Rehabilitation and

Ergonomics, Fondazione Salvatore Maugeri,

IRCCS, Istituto Scientifico di Veruno, Via

Revislate 13, 28010 Veruno (NO), Italy.

 Address correspo ndence to G.F.; e-mail:

giorgio.ferriero@fsm.it 

Disclosure: nothing to disclose

F.S. Unit of Occupational Rehabilitation and

Ergonomics, Fondazione Salvatore Maugeri,

IRCCS, Istituto Scientifico di Veruno, Veruno

(NO), Italy

Disclosure: nothing to disclose

C.F. Department of Physical and Rehabilita-

tion Medicine, University of Rome “Tor Ver-

gata,” Rome, Italy

Disclosure: nothing to disclose

D.P. Department of Physical Medicine and

Rehabilitation, Fondazione Salvatore Maugeri,IRCCS, Turin, Italy

Disclosure: nothing to disclose

E.B. Department of Physical Medicine and

Rehabilitation, University of Pavia, Italy

Disclosure: nothing to disclose

S.V. Unit of Occupational Rehabilitation and

Ergonomics, Fondazione Salvatore Maugeri,

IRCCS, Istituto Scientifico di Veruno, Veruno

(NO), Italy

Disclosure: nothing to disclose

Submitted for publication April 28, 2011;

accepted May 13, 2011.

PM&R © 2011 by the American Academy of Physical Medicine and Rehabilitation1934-1482/11/$36.00 Vol. 3, 1153-1154, December 2011

Printed in U.S.A. DOI: 10.1016/j.pmrj.2011.05.0141153

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methods and has the advantage of being based on a handheldsmartphone device, which is instantly available for use.

The results of this study cannot be generalized. Onelimitation is that the subjects whom we investigated werehealthy, and consequently the positioning of the virtual go-niometer on their pictures was not as difficult as it wouldhave been in the case of obese patients or patients withorthosis or limb deformations. Another limitation is that the

raters made their measurements on pictures previously takenby others. Nevertheless, in a previous study, Ferriero et al[14] demonstrated that the picture itself did not significantlyinfluence the interrater reliability if taken correctly.

In conclusion, DrG is reliable for elbow joint goniometry.DrG can be used as an alternative or additional method totake the measurement, is useful for many different clinicalneeds and settings (eg, follow-up after treatment, assessmentof intraoperative joint mobility, medico-legal purposes). Fur-ther studies are needed to assess the validity of this simpleapplication in measuring the ROM of other joints besides theelbow and in other clinical conditions, and for use of thismethod interchangeably with the UG.

REFERENCES

1. RothsteinJM, Miller PJ,Roettger RF.Goniometric reliability in a clinical

setting. Elbow and knee measurements. Phys Ther 1983;63:1611-

1615.

2. Fish DR, Wingate L. Sources of goniometric error at the elbow. Phys

Ther 1985;65:1666-1670.

3. Gajdosik RL, Bohannon RW. Clinical measurement of range of motion.

Review of goniometry emphasizing reliability and validity. Phys Ther

1987;67:1867-1872.4. Georgeu GA, Mayfield S, Logan AM. Lateral digital photography with

computer-aided goniometry versus standard goniometry for recording

finger joint angles. J Hand Surg Br 2002;27:184-186.

5. Dunlevy C, Cooney M, Gormely J. Procedural considerations for pho-

tographic-based joint anglemeasurements. Physiother Res Int 2005;10:

190-200.

6. Cleffken B, van BreukelenG, Brink P, vanMameren H, Olde-Damink S.

Digital goniometric measurement of knee joint motion. Evaluation of 

usefulness for research settings and clinical practice. Knee 2007;14:

385-389.

7. Bennett D, Hanratty B, Thompson N, Beverland D. Measurement of 

knee joint motion using digital imaging. Int Orthop 2009;33:1627-

1631.

8. Smith RP, Dias JJ, Ullah A, Bhowal B. Visual and computer software-

aided estimates of Dupuytren’s contractures: Correlation with clinical

goniometric measurements. Ann R Coll Surg Engl 2009;91:296-300.

9. Portney LG, Watkins MP. Foundations of Clinical Research: Applica-

tions to Practice. Upper Saddle River, NJ: Prentice Hall Health; 2000.

10. Boone DC, Azen SP, Lin CM, Spence C, Baron C, Lee L. Reliability of 

goniometric measurements. Phys Ther 1978;58:1355-1360.

11. Adams LS,Greene LW,TopoozianE. Range of motion. In:Casanova JS,

ed. Clinical Assessment Recommendations. 2nd ed. Chicago, IL: Amer-

ican Society of Hand Therapists; 1992, 55-70.

12. Edgar D, Finlay V, Wu A, Wood F. Goniometry and linear assessments

to monitor movement outcomes: Are they reliable tools in burn survi-

vors? Burns 2009;35:58-62.

13. Hoffmann T, Russell T, Cooke H. Remote measurement viathe Internet

of upper limb range of motion in people who have had a stroke. J

Telemed Telecare 2007;13:401-405.14. Ferriero G, Vercelli S, Sartorio F, Brigatti E, Ruella C, Primavera D. A

new iPhone-based goniometer (DrGoniometer): A validation study.

17th Physical and Rehabilitative Medicine European Congress, May

23-27, 2010, Venice, Italy.

Figure 1. Example of goniometric measurement usingDrGoniometer as it appears on the smartphone screen.

1154 Ferriero et al  DRGONIOMETER FOR ELBOW ANGLE MEASUREMENT