Elsevier

Gait & Posture

Volume 36, Issue 3, July 2012, Pages 335-339
Gait & Posture

Comparing the reliability of a trigonometric technique to goniometry and inclinometry in measuring ankle dorsiflexion

https://doi.org/10.1016/j.gaitpost.2012.01.019Get rights and content

Abstract

Objectives

The purpose of this study was to compare the reliability of three previously used techniques for the measurement of ankle dorsiflexion ROM, open-chained goniometry, closed-chained goniometry, and inclinometry, to a novel trigonometric technique.

Methods

Twenty-one physiotherapy students used four techniques (open-chained goniometry, closed-chained goniometry, inclinometry, and trigonometry) to assess dorsiflexion range of motion in 24 healthy volunteers. All student raters underwent training to establish competence in the four techniques. Raters then measured dorsiflexion with a randomly assigned measuring technique four times over two sessions, one week apart. Data were analyzed using a technique by session analysis of variance, technique measurement variability being the primary index of reliability. Comparisons were also made between the measurements derived from the four techniques and those obtained from a computerized video analysis system.

Results

Analysis of the rater measurement variability around the technique means revealed significant differences between techniques with the least variation being found in the trigonometric technique. Significant differences were also found between the technique means but no differences between sessions were evident. The trigonometric technique produced mean ROMs closest in value to those derived from computer analysis.

Conclusions

Application of the trigonometric technique resulted in the least variability in measurement across raters and consequently should be considered for use when changes in dorsiflexion ROM need to be reliably assessed.

Highlights

► Inter-rater reliability is poor when measuring ankle dorsiflexion using goniometry. ► Four techniques for measuring ankle dorsiflexion ROM were assessed. ► Trigonometry was found to be the most reliable technique in measuring dorsiflexion. ► Trigonometry returned ROM values most similar to that found with video analysis.

Introduction

Efficient ambulation through a cluttered environment results from the interaction of numerous musculoskeletal, neurological, cardiovascular and environmental constraints. Range of motion of the lower extremity joints is one such constraint that can influence the mobility of an individual. Adequate ankle ROM is particularly important for mobility because the foot lies at the distal end of a kinetic chain and therefore is the most frequent interface with the environment. Limited ankle dorsiflexion is an impediment to the performance of activities of daily living such as rising from a chair [1] and stair climbing [2]. It is essential therefore, that physiotherapists be able to accurately and reliably assess ankle dorsiflexion ROM so that the effects of injuries, disease processes and therapeutic interventions on functional activities can be evaluated.

The clinical assessment of ankle ROM is typically achieved through goniometric techniques despite the fact that empirical research has suggested that goniometry is frequently an unreliable procedure [3], [4]. Lack of reliability has been attributed to variability in such factors as landmark determination, instrument alignment, positioning, and the force applied by the therapist [5], [6]. With respect to ankle dorsiflexion ROM, both non weightbearing open-chain and weightbearing closed-chain goniometry have been investigated. In open-chain goniometry (OCG), a number of studies [7], [8] have suggested that difficulty in standardizing the procedures decreases the reliability of this technique. Investigations have also compared the reliability of OCG with that of closed-chain goniometry (CCG) [9], [10]. Hagins [10] for example, found little correlation between OCG and CCG in the assessment of ankle dorsiflexion ROM, concluding that the ability to perform functional activities cannot be predicted from non-weightbearing measurements.

Typically when goniometric reliability is assessed both inter- and intra-rater reliability is examined with the usual finding being that intra-rater reliability is greater than inter-rater reliability [11], [12]. For example, Youdas et al. [12] in an examination of goniometry and visual estimation found that intra-rater goniometric measurements were the most reliable but neither technique was found to have high inter-rater reliability.

Physiotherapy clearly requires a measurement technique that will be reliable when used on different days and by different clinicians. A number of researchers have also suggested that dorsiflexion ROM should be measured under weightbearing conditions as this better simulates how the ankle behaves in most functional activities of which gait is perhaps the most important. For this reason Bennell et al. [13] and Munteanu et al. [14] assessed the reliability of ankle dorsiflexion measurement using a lunge position. Bennell et al. [12] had healthy individuals adopt a lunge position, flexing the knee hit until it hit a wall. The distance from the distal end of the great toe to the wall was then measured as an index of ankle dorsiflexion ROM, larger distances being associated with greater ROM. However, the researchers did not take into account the effect that foot length would play in determining the distances measured. Furthermore, such a technique is not able to assess dorsiflexion ROM with the knee straight and thus is not capable of examining the influence of the gastrocnemius in constraining ankle ROM. Munteanu et al., [14] also examined dorsiflexion ROM in a lunge position but this time with the knee straight. The researchers used an inclinometer placed along the anterior tibial border and a custom made clear acrylic plate to record peak angle.

The current work also assesses dorsiflexion ROM in a lunge position with the knee extended but uses simple trigonometry rather than a custom made plate to determine the angle. The reliability of this novel technique is compared to that derived from inclinometry over the achilles tendon and traditional OCG and CCG assessment.

In the assessment of goniometric reliability, most studies have used a test–retest paradigm with the calculation of intraclass correlation coefficients being the typical tool for statistical analysis. Such test–retest experimental designs can be unintentionally influenced by rater expectations. The ROM a rater records on one day for a given participant might influence the ROM the rater records for the same participant on subsequent occasions. In an attempt to prevent such biases from influencing the results, experimenters frequently blind the rater to the recording instrument's scale, requiring that the experimenter read the instrument. Such a procedure, of course, detracts from the ecological validity of the study and undoubtedly influences the reliability reported for the techniques being analyzed.

The current research avoids such problems by not having raters measure ROM on any participant more than once. Rather than using intraclass correlations we analyze the mean and the individual raters measurement deviation about the mean for each technique across days. Theoretically, with a given sample of ankles, the mean ROM and the variability around that mean across days should be the same regardless of the technique used or rater responsible for applying the technique. The mean of the differences between the raters’ readings and the grand mean provides a further, more fine-grained estimate of the reliability of a given technique. Techniques that are more reliable should exhibit lower rater variability, as raters tend to report similar ROM with that technique. The use of measurement variability as an index of reliability is used here in the same way that the standard error of measurement (SEM) has been previously used to assess one aspect of reliability [15].

Section snippets

Methods

Twenty-four (N = 24, 17 females, 7 males, mean age = 24.3 yrs) students volunteered to serve as participants. Twenty-one senior physiotherapy students (13 females, 8 males, M = 24.3 yrs) were recruited as raters. All raters had completed at least one clinical affiliation and had passed lab courses in musculoskeletal assessment and therapeutic skills. Participants were required to have no history of ankle injury. All participants and raters signed informed consent forms prior to the start of the

Results

The technique by session ANOVA performed on the mean ROM data revealed a main effect of technique F (3,80) = 56.5, p < 0.0001 but no effect of session F < 1 (see Table 1). Post hoc analysis indicated that the ROM mean derived through trigonometry (M = 33.1°, SD = 3.5) was significantly greater than all other technique means. Furthermore, the mean from inclinometry (M = 29.4°, SD = 9.9) was significantly greater than that from OCG (M = 11.3°, SD = 6.3) but not CCG (M = 26.1°, SD = 6.9). Finally, the mean derived

Discussion

Gait is fundamental to many activities of daily living and as such, the assessment of factors that might contribute to gait dysfunction is a basic skill requirement for many physiotherapists. Clearly then, a valid and reliable technique for measuring ROM at the ankle is essential for clinical practice. A technique that measures ROM in a functional weightbearing position is usually preferable to one in which the clinician attempts to determine the joint end range in an open chain position. In a

Conclusion

The present study examined the reliability of four techniques for measuring ankle dorsiflexion. The trigonometric technique proved to be the most reliable procedure and recorded a mean ROM closest to the angle determined by computerized video analysis. If one wishes to reliably and validly assess weightbearing dorsiflexion ROM in the clinic, the simple and easy to use trigonometric technique should be seriously considered.

Conflict of interest statement

No conflicts of interest arose in conducting this work for any of the authors.

Acknowledgement

No financial assistance was used in conducting this work.

References (16)

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This study was approved by the Husson University's Institutional Review Board.

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