لخّصلي

The measurement of joint range of motion (ROM) in static and dynamic, passive and active, human movements is an essential skill in the musculoskeletal assessments commonly performed by physiotherapists, as well as some strength and conditioning coaches, to examine joint function, detect joint asymmetry and evaluate treatment efficacy as an objective outcome measure [1].This state-of-the-art review will assist clinical practitioners in deciding the appropriateness and choice of smartphone apps for clinical ROM assessment.These potential issues highlighted for the use of the universal goniometer in assessing static joint ROM may be further exacerbated in inexperienced clinicians who have a relative inability to correctly locate anatomical landmarks; as well as the assessment of dynamic rather than static ROM [10, 11].In psychometric terminology, reliability deals with the consistency in angle and displacement measures produced by smartphone apps, when used by multiple assessors (inter-rater), and when the same assessor performs multiple measurements (intra-rater) [13].The purpose of this systematic review was to address some of the limitations of the previous review in this area so as to better assist the clinician identify which smartphone apps may show adequate inter-rater and intra-rater reliability as well as validity for the measurement of ROM at particular joints and actions in clinical practice.On the topic of synthesizing the psychometric properties of smartphone apps, a number of systematic reviews have been conducted [14, 15].

The measurement of joint range of motion (ROM) in static and dynamic, passive and active, human movements is an essential skill in the musculoskeletal assessments commonly performed by physiotherapists, as well as some strength and conditioning coaches, to examine joint function, detect joint asymmetry and evaluate treatment efficacy as an objective outcome measure [1]. In the present study, static ROM is defined as the range of a joint held motionless at either of its limit of movement. Dynamic ROM is the range a joint moved to and from the limits of movement. When a joint is moved passively by an assessor or external device, passive ROM is assessed. When a joint moves as a result of muscular contraction, active ROM is assessed. The universal goniometer has long been the preferred method of clinical ROM measurement (especially static ROM) due to its ease of use, low cost, and demonstrated reasonable levels of reliability and validity in numerous studies [2–4].

However, the universal goniometer is not without its drawbacks, even when assessing static joint ROM. When assessing static ROM such as the angle of hinge joints like the knee and elbow in adults, there may always be some degree of error due to the universal goniometer not typically being long enough to be aligned directly with the appropriate landmarks on both proximal and distal adjacent joints. Spinal rotation may also be difficult to measure with a universal goniometer due to the difficulty in palpating anatomical landmarks to use as a reference point [5–7]. It is perhaps no surprise then that reliability is reduced when measuring the spinal compared to upper and lower limb motion with a universal [6–9]. These potential issues highlighted for the use of the universal goniometer in assessing static joint ROM may be further exacerbated in inexperienced clinicians who have a relative inability to correctly locate anatomical landmarks; as well as the assessment of dynamic rather than static ROM [10, 11].

The development of smartphone technology and software applications (apps), coupled with the ubiquity of smartphone ownership, now allows smartphones to measure joint ROM. Like the universal goniometer, smartphones are similarly easy to use, relatively inexpensive, and highly accessible [12]. Their inbuilt sensors such as an accelerometer, gyroscope, and magnetometer provide the necessary equipment to allow the smartphone to measure angles and displacements [12]. With the use of apps that can be downloaded onto the smartphone, these measurements can be transformed into meaningful assessment data such as joint ROM. One possible advantage of smartphone apps is that their use may circumvent some of the difficulties of using the universal goniometer regarding landmark identification and alignment. Where smartphone apps can altogether overcome the aforementioned drawbacks of the universal goniometer may depend upon the technology used and the experience of the clinician with this alternative approach. The emergence of smartphone apps therefore presents the clinical practitioners with a new set of tools to incorporate into clinical practice, especially for some of the more difficult joint ROMs to quantify.

In order for clinicians to be willing to replace the universal goniometer (at least in some contexts) with smartphone apps as a tool to clinically assess ROM, the validity and reliability of smartphone apps must be comparable or better than the universal goniometer. In psychometric terminology, reliability deals with the consistency in angle and displacement measures produced by smartphone apps, when used by multiple assessors (inter-rater), and when the same assessor performs multiple measurements (intra-rater) [13]. Validity deals with the extent that the measurement obtained from one device, such as smartphone apps, correlates or matches the criterion laboratory devices such as 3-D motion capture or criterion clinical tools such as the universal goniometer [13].

On the topic of synthesizing the psychometric properties of smartphone apps, a number of systematic reviews have been conducted [14, 15]. However, the review of Milani et al. [14] is considered to be outdated due to the relative explosion of research into human movement analysis apps and as such, only included 12 studies assessing joint angle measurements. Further, while the review of Rehan Youssef and Gumaa [15] was more recent and well conducted in most aspects, there were several methodological limitations. First, their literature search was completed in August 2016 (including 15 studies and one case study assessing joint ROM) [15]. Second, they utilised a non-validated risk of bias assessment tool that they personally developed [15]. Third, there was a relative lack of reporting of specific reliability and validity data for each of the multiple actions that can occur at some joints such as the spine (trunk) and shoulder joints [15]. The relative lack of reporting specific data for each joint action is a major issue for clinicians, as it is quite possible that a particular smartphone and app may have sufficient reliability and/or validity or measuring some actions at a particular joint in certain planes of motion (e.g. flexion and extension in the sagittal plane) but that more complicated actions such as rotation in the transverse plane may be less reliable and/or valid.

The purpose of this systematic review was to address some of the limitations of the previous review in this area so as to better assist the clinician identify which smartphone apps may show adequate inter-rater and intra-rater reliability as well as validity for the measurement of ROM at particular joints and actions in clinical practice. This state-of-the-art review will assist clinical practitioners in deciding the appropriateness and choice of smartphone apps for clinical ROM assessment.