ABSTRACT
Background: Clinically, a discrepancy of fibular position in relation to the tibia has been proposed as a factor in the persistence of chronic ankle instability (CAI). Previous studies have produced conflicting findings, perhaps due to varying radiological methods and measurement of participants in non-weight-bearing positions.
Objectives: To compare normalized-fibular position in weight-bearing in individuals with CAI with healthy controls.
Design: A weight-bearing lateral X-ray was taken of the affected ankle of 33 adults with CAI and 33 matched controls. The distance between the anterior edges of the distal fibula and tibia was recorded, and then normalized as a proportion of maximal tibial width. Normalized-fibular position was compared between groups using independent t-tests. Intra-class correlation coefficients (ICC2,1) were calculated to determine reliability of measurements. A receiver-operating characteristic (ROC) curve was used to determine sensitivity, specificity, and a cutoff score to differentiate individuals with CAI from controls using normalized-fibular position.
Results: Normalized fibular position was significantly different (CAI, 29.7 (6.6)%; healthy, 26.7 (4.8)%) between the groups. Measurement of intra-rater (0.99, 95%CI = 0.98 to 1.00) and inter-rater (0.98, 95%CI = 0.96 to 0.99) reliability were both excellent. The threshold normalized-fibular position was 27%, with a score more than 27% indicating a greater chance of being in the CAI group. Sensitivity was 69.7% and specificity was 54.5% for this threshold.
Conclusion: A slightly posteriorly positioned fibula in relation to the tibia was observed in people with CAI. Specificity/sensitivity scores for normalized-fibular position indicate that it has little ability to predict CAI alone.
KEYWORDS: Distal tibio-fibular joint, ankle sprain, stress radiographs, fibular displacement, reliability
Introduction
The ‘positional fault hypothesis’ was proposed in 1993 by Brian Mulligan [1] to explain the benefits of Mobilization With Movement (MWM) in the treatment of joint injuries. According to this hypothesis, joint injuries or sprains might result in a minor bony incongruence. In relation to ankle joint inversion injuries, the distal fibula may become anteriorly positioned in relation to the tibia following injury [2], causing painful restrictions in physiological movement [3]. The presence of such a fibular positional abnormality remains controversial. Whether an abnormally positioned fibula predisposes to injury, or whether inversion injury may result in an anteriorly positioned fibula, is yet to be examined [4].
The presence of an abnormally positioned fibula has been explored in acute to chronic ankle sprains and also in chronic ankle instability (CAI) [4–14], using fibular movement measured by potentiometer, 3D CT-based bone models, and radiological investigations involving MRI, CT, fluoroscopy, and X-rays. These studies utilized different indices to determine fibular position including axial malleolar index (AMI), intra-malleolar index (IMI), and the malleolar talar index (MTI) [9,10,12,14]. Fibular position has also been measured radiographically as the distance between the most anterior margin of the tibia and the most anterior margin of the fibula on a lateral view [2,4]. Because of possible superimposition of anatomy (fibular position by the size of the tibia) on the lateral projection, a normalization technique has been suggested which reports fibular position as a percentage of tibial width [15].
While some studies support the presence of an alteration in fibular position in CAI, others indicate no such findings [13,16]. Where a fibular positional anomaly has been detected, there are mixed findings regarding the direction of the displacement, including anterior [4], posterior [9], lateral [11], and antero-inferior [5]. These inconsistencies may possibly be due to different radiological methods or methods of measurement [2] used across the various studies. It is also possible that alterations in fibular position may be better observed in functional positions such as standing. However, all studies assessing CAI undertaken to date have utilized non-weight-bearing positions. A study assessing fibular movements in healthy ankles reported that there is an outward and backward displacement of the fibula in relation to the tibia while the foot moves from plantarflexion to dorsiflexion while standing on a specially designed platform (n = 10) [17]. This indicates the influence of weight-bearing on the position of the fibula in healthy ankles and so it may be worthwhile to explore this in CAI.
It may be important to assess the position of the fibula in a weight-bearing position as this is a more functional position and likely more clinically relevant. A detectable difference in fibular position in a weight-bearing position in patients with CAI, as compared to healthy individuals could well be important in their clinical management. Demonstration of the existence of an altered fibular position could provide some support for physical interventions aimed at ‘correcting a fibular positional fault,’ and provide a possible explanation for persistent ankle pain and dysfunction following injury in some cases [2].
To date, researchers have not investigated differences in fibular position between injured and healthy individuals in a weight-bearing position, or adequately demonstrated the diagnostic utility of any imaging method of fibular position. Quantifying values for reliability, specificity and sensitivity measures, and cutoff scores for fibular positional changes that may be clinically relevant, could be of assistance in the therapeutic management of CAI.
The purpose of this study was to identify any differences in normalized fibular position in a weight-bearing position between people with CAI and healthy volunteers. In addition, we aimed to establish diagnostic utility measures including inter-rater and intra-rater reliability, specificity and sensitivity, and cutoff scores for normalized fibular position.
Methods
Participants with CAI and participants with healthy ankles aged 18 years and over were recruited through posted flyers, social media, and using media releases (from October 2017 to April 2018). The volunteers with CAI were considered eligible if they satisfied the inclusion and exclusion criteria as endorsed by the International Ankle Consortium [18], with the exception that the duration for undergoing at least two episodes of giving way of the ankle was changed from six to 12 months considering the seasonal nature of some sports. Individuals with a history of at least one significant ankle sprain and giving way, and/or a recurrent sprain, and/or a feeling of instability, were included in the CAI group. Individuals were excluded from the CAI group if they reported a history of previous surgery or fractures in the lower extremity, current or previous injury to the ankle including isolated distal tibiofibular syndesmotic sprains, neuromuscular disorders causing problems in the lower limb, conditions contraindicating radiological imaging, and an inability to read English. Volunteers with healthy ankles (age and gender matched) were accepted into the study if they had no prior history of ankle problems, lower limb surgery or other ankle treatment, and reported no current pain or problems in or around the ankle while performing daily activities. The same exclusion criteria were applied for volunteers with both CAI and healthy ankles. The University of Newcastle Human Research Ethics Committee granted ethical approval for the study (H-2017-0217). Informed consent was obtained from all participants and the rights of them were protected.
An X-ray (55 k Vp and 2.1 mAs) was taken of the most affected ankle of the people with CAI to measure the fibular position with respect to the tibia in weight-bearing (neutral ankle in standing position). The most affected side was determined using the Cumberland Ankle Instability Tool (CAIT) [19]. CAIT is a self-reported questionnaire used to determine the presence of ankle instability, with a cutoff score ≤24 indicating an unstable ankle [18]. If participants presented with a similar score for both ankles, they were asked to verbally nominate the most problematic ankle. If they were unable to distinguish between ankles, the dominant side was imaged. Volunteers with healthy ankles were age and gender matched to the participants with CAI, with the same ankle (left, right) imaged.
Each participant was instructed to stand on the affected foot with the knee slightly flexed representing mid-stance as at normal gait speed of the gait cycle, with the foot of the other leg hanging relaxed. Full bodyweight was transferred through the tested leg at the time of imaging. The hip of the imaged leg was placed in about 45–50° of flexion and the knee in 15–20° flexion, with the ankle dorsiflexed to approximately 5° [20–22]. The other leg was positioned such that the hip was approximately extended 25–30°, the knee flexed about 40–45° and the ankle was permitted to hang. Both arms were placed across the chest of the participant, and no external support was provided. Approximately 2 cm distance was maintained between the imaged foot and the parallel image receptor. All participants were provided with similar instructions and the position of the leg was monitored throughout the procedure. The X-ray was repeated once if any leg rotation was observed on imaging. The central ray was directed to the base of the metatarsals and perpendicular to the image receptor, thus the inclusion of the entire foot in the image could demonstrate stability and uniformity of position with weight-bearing distributed throughout the foot. The focal-film distance was set to 110 cm. To ensure the lateral X-ray was acceptable, each individual image was viewed immediately after exposure, while the participant maintained the same position of the imaged foot but could take some weight back on the other foot if desired. As the image was visible after approximately 10 seconds, this allowed for adjustments to the position of the participant and a new image to be taken if required. As the radiograph was a lateral view, it was considered acceptable if superimposition of the talar domes was present, thus permitting a clear view of an open tibio-talar joint and allowing planned measurements to be undertaken. The participant was permitted to lightly hold the body of the X-ray machine for balance, if necessary [23].
Merge PACSTM software (Merge Health Care, 2012) was used to digitally record all radiographic images. The distance between the anterior edges of the distal fibula and the distal tibia was recorded as the fibular position (Figure 1) [4]. Measures of fibular position were normalized to tibial width, and the tibial width defined as the maximum distance between the anterior and posterior tibial processes within the distal epiphysis, in a lateral view X-ray image. Normalization of measurements was undertaken to minimize the potential error that could be introduced due to anatomical variation between individuals. All the X-ray radiographs were performed by a registered diagnostic radiographer (JT) with over 30 years of clinical experience.
Figure 1.
Measurement of normalized fibular position (normalized to tibial width; normalized fibular position, 17.39% = (fibular position (a), 6.8 mm/maximum tibial width (b), 39.1 mm) x 100. (A) = distance between the anterior edge of the distal fibula and the anterior edge of the distal tibia. (B) = maximum distance between the anterior tibial process and the posterior tibial process within the distal epiphysis.
A random selection of 24 ankle X-rays (CAI = 12, healthy = 12) were used to determine the reliability measures. These X-rays were independently evaluated by two assessors (a registered physical therapist [IW], and a registered radiographer [JT]). Both the assessors were experienced in the use of the Merge PACSTM software (Merge Health Care, 2012). Each tester individually completed measurements on one occasion to determine inter-rater reliability measures, and one tester (IW) undertook further blinded measurements on a second occasion (2 weeks later) for intra-rater reliability measures.
Analysis
The primary outcome measure of fibular position [4] was used in sample size calculations. The sample size estimation (mean difference [MD] = 2.5, SD = 3.4) [4] resulted in a minimum sample size of 33 participants per group allowing for a 10% for data loss, alpha of 0.05, and achieving power of 0.80.
Baseline measures were assessed for normality using the Shapiro-Wilk normality test. Descriptive statistics were calculated for all variables. Comparison of means between the normal and CAI groups were analyzed using independent t-tests. The effect size was calculated using Cohen’s d for normalized fibular position.
Relative reliability of the measures was assessed using intra-class correlation coefficients (ICC 2,1) and 95% confidence intervals (CIs). The SEM was calculated to assess measurement precision using the formula, SEM = SD × √ (1 – ICC), with SD representing the standard deviation of the measure [24].
The ability of the measures of normalized fibular position to identify people with CAI was calculated using the area under the receiver operating characteristic (ROC) curves and the 95% CIs of the area under the curve (AUC). A traditional academic point scale was utilized to determine the accuracy of the AUC and the 95% CIs of the AUC for discriminating between healthy participants and those with CAI (0.90–1.00, excellent; 0.80–0.89, good; 0.70–0.79, acceptable; 0.60–0.69, poor; and 0.00–0.59, failure) [16]. In addition, a cutoff score (for discriminating people with CAI from healthy people) with resulting likelihood ratios and 95% CIs were quantified for normalized fibular position. The cutoff score was determined by calculating the Youden index (J) for fibular position along the ROC curve, with the largest J value representing the cutoff score [16,25]. Further, positive (LR+) and negative (LR−) likelihood ratios were produced (LR+ = (sensitivity/(1 – specificity), LR− = (1 – sensitivity)/specificity)) [25,26].
All statistical analyses were performed using IBM SPSS (Version 23.0, Armonk, NY, IBM Corp) and an a priori α level was set at p = 0.05 for all the analysis.
Results
Sixty-six participants were included in the study after assessing eligibility. An outline of the recruitment process is provided in Figure 2. Common reasons for exclusion included previous ankle injury (n = 13 in CAI group) and unable to match with CAI group (n = 6 in healthy group).
Figure 2.
Overview of the recruitment process.
Participant characteristics
Data from 33 people with chronic unstable ankles (11 males; mean (SD) age 30.24 (8.70) years; mean (SD) body mass index (BMI) 25.30 (4.46 kgm−2)) and 33 age and gender matched healthy controls (11 males; mean (SD) age 30.45 (8.71) years; mean (SD) BMI 23.47 (3.51 kgm−2)) were included in the study. Participant characteristics are presented in Table 1.
Table 1.
Characteristics of the participants.
| Baseline data | HEALTHY (n = 33) Mean (SD) |
95% CI |
CAI (n = 33) Mean (SD) |
95% CI |
p Value |
|---|---|---|---|---|---|
| Age | 30.5 (8.7) |
27.4 to 33.5 | 30.2 (8.7) |
27.2 to 33.3 | 0.92 |
| Height | 169.5 (9.2) |
166.3 to 172.8 | 170.6 (7.6) |
167.9 to 173.3 | 0.61 |
| Weight | 67.8 (13.6) |
63.0 to 72.6 | 73.7 (14.3) |
68.7 to 78.8 | 0.09 |
| BMI | 23.5 (3.5) |
22.2 to 24.7 | 25.3 (4.5) |
23.7 to 26.9 | 0.07 |
| CAIT score affected/matched side | 29.0 (1.5) |
28.5 to 29.6 | 13.8 (4.3) |
12.3 to 15.3 | <0.01 |
| CAIT score other side | 29.0 (1.5) |
28.5 to 29.5 | 21.1 (6.7) |
19.7 to 23.4 | <0.01 |
| FAAM ADL score | 99.9 (0.4) |
99.8 to 100.0 | 89.1 (8.5) |
86.1 to 92.1 | <0.01 |
| FAAM Sports score | 99.4 (2.2) |
98.6 to 100.1 | 70.1 (2.3) |
65.7 to 74.4 | <0.01 |
ADL, activities of daily living; BMI, body mass index; CAI, chronic ankle instability; CAIT, Cumberland Ankle Instability Tool; FAAM, Foot and Ankle Ability Measure; SD, standard deviation
The height, weight, and BMI measures were statistically similar in both groups. The CAI group was functionally impaired with a significantly different mean FAAM score (Table 1). Further, the dominant leg was unstable in 20 participants in the CAI group. Twenty-six participants of the CAI group had sprained their other ankle; however, it was not reported as unstable.
Comparison of fibular position
No significant difference between the two groups was noted for non-normalized fibular position (MD = −1.24 mm [95%CI = −2.85 to 0.37], p = 0.13). However, there was a significant difference in normalized fibular position (MD = −3.01% [95%CI = −5.83 to −0.19], p = 0.04) (Table 2). The effect size was d = 0.53 for normalized fibular position.
Table 2.
Comparison of fibular position between individuals with unstable ankles and healthy ankles.
| Fibular position | HEALTHY (n = 33) Mean (SD) |
CAI (n = 33) Mean (SD) |
p Value (MD, 95% CI) |
|---|---|---|---|
| Non-normalized fibular position (mm) | 11.54 (2.89) | 12.78 (3.63) | 0.13 (1.24, -0.37 to 2.85) |
| Normalized fibular position (%) | 26.69 (4.78) | 29.7 (6.55) | 0.04 (3.01, 0.19 to 5.8) |
CAI, chronic ankle instability; MD, mean difference; SD, standard deviation
ROC analysis
The AUC for the ROC curve (Supplementary material 1) was not significant indicating that the fibular position values cannot independently predict having CAI. The largest Youden index value indicated that a normalized fibular position value of greater than 27% was the cutoff score to distinguish the CAI group (Supplementary material 2). In the other words, the anterior portion of the fibula was 27% of the tibia’s width away from the anterior border of the tibia in CAI. Moderate sensitivity (70%) and fair specificity (55%) were calculated at this cutoff for normalized fibular position. Resulting positive and negative likelihood ratios were 1.53 and 0.56, respectively.
Reliability of the weight-bearing X-ray measures of fibular position
Inter-rater reliability and intra-rater reliability were excellent for all the fibular position measures with high ICC (2,1) values, and low SEM values (Table 3).
Table 3.
Intra-class correlation coefficient (ICC2,1) and standard error of measurement (SEM) with 95% confidence intervals (CI) for inter-rater and intra-rater reliability of measurements of fibular position.
| Measurement | Intra-rater reliability | Inter-rater reliability |
|---|---|---|
| Non-normalized fibular position ICC (95% CI) SEM 95% CI (1.96 × SEM) |
1.00 (0.99–1.00) 0.56 1.10 |
0.98(0.96–0.99) 0.97 1.91 |
| Tibial width ICC (95% CI) SEM 95% CI (1.96 × SEM) |
1.00 (1.00) 0.57 1.12 |
0.98(0.96–0.99) 1.12 2.19 |
| Normalized fibular position ICC (95% CI) SEM 95% CI (1.96 × SEM) |
0.99(0.98–1.00) 1.33 2.60 |
0.98(0.96–0.99) 1.75 3.43 |
Discussion
The present study of fibular position in people with CAI is the first to be conducted with participants weight-bearing in standing. A significant difference in fibular position in people with CAI was found compared to people with healthy ankles when normalized for tibial width, which may suggest CAI is associated with a slight posteriorly position of the fibula in a weight-bearing position. Although the magnitude of detected difference in the current study was small, the effect size was moderate (d = 0.53). This indicates that people with CAI have a more posteriorly displaced fibula (0.53 standard deviations higher) than people with healthy ankles [27]. Clinically, this may be a factor contributing to the persistence of pain, range of motion restriction and other symptoms and signs in some cases of CAI. The finding of an posteriorly positioned fibula in the present study lends contradiction to Mulligan’s hypothesis of a fibular ‘positional fault’ in chronic cases of injury or sprain of the ankle [2]. It also contradicts the biological rationale for MWM which attempts to correct the ‘positional fault’ through the pain-free application of a manual glide (usually a posteriorly directed mobilization) of the fibula while the patient performs the impaired active or functional movements. While the mechanism leading to the observed posterior fibular positional change in CAI is unclear, it may be associated with mechanical instability in some cases. The incidence of isolated distal tibiofibular syndesmotic sprains is reported as being between 1% and 11% in the general population [28]. Any change in fibular position could potentially be due to an undiagnosed syndesmotic sprain or instability of the anterior syndesmosis of the ankle in certain individuals.
In our study, the distance between the anterior margin of the tibia and the anterior margin of the fibula was measured to determine the fibular position, using lateral X-rays taken in a weight-bearing position. To allow for individual morphological differences, this measurement was also normalized by calculating it as a percentage of the tibial width. No previous studies have investigated fibular position in a weight-bearing position to facilitate comparison of our findings. However, there are a few studies investigating fibular positional changes conducted in non-weight-bearing positions using radiological methods, such as fluoroscopy [4], X-ray generators [15], MRI [5,9,14], and CT [9–12], and non-radiological methods, such as a potentiometer [6]. In these studies, participants were positioned in either side-lying or supine lying. In addition, the ankle was held in a variety of positions, including maximal dorsiflexion in one study [4], neutral in the majority of studies [5,6,11,12,14], and was not mentioned in one study [15].
Previous research on the existence of an altered fibular position in CAI is somewhat conflicting. Two studies found no fibular positional differences between healthy and CAI participants [6,15]; however, the others all support the existence of a fibular positional change. However, the direction of this change varies between these studies, with most finding either an anteriorly positioned [4,6,14] (contradictory with the present study) or a posteriorly positioned fibula [9,10,12]. Further, an antero-inferior displacement [5] and a laterally positioned fibula have also been observed [11]. Some of the differences in findings across studies may be due to the use of different measures. The AMI [9,10,12] is most commonly utilized in MRI studies where it shows the position of the fibula in relation to the tibia at the ankle mortise [9]. In radiographic studies, the ‘distance between anterior margin of the tibia and anterior margin of the fibula’ is commonly used [4,14,15]. The studies of Kobayashi et al. [11] and Kavanagh et al. [6] used other customized measures. Moreover, normalization of fibular position was used in only one previous study because of possible superimposition of fibular position by the size of the tibia on the lateral projection, [15] making this just the second study to do so.
Consistent with previous research using fluoroscopic non-weight-bearing images [4], weight-bearing lateral X-ray measures in the current study demonstrated excellent reliability (intra-rater and inter-rater) for both normalized and non-normalized fibular position. A weight-bearing lateral X-ray is arguably more functional and more clinically relevant than other available methods for measuring fibular position. Further, the low SEM values (Table 3) indicate good precision for estimation of both normalized and non-normalized fibular position. On the other hand, only moderate sensitivity (70%) and fair specificity (55%) were observed at the cutoff value for identifying the people with CAI using normalized fibular position (≥27%) in the current findings. These sensitivity and specificity values demonstrate a moderate ability of the normalized fibular position to predict the presence of CAI when the test is positive (≥27%), and a minimal ability to exclude the presence of CAI when the test is negative [29].
Given that the mechanism of CAI may sometimes be multifactorial (mechanical and/or functional), it is perhaps not surprising that the normalized fibular position measure discriminated between the two groups (CAI and healthy) with a point estimate accuracy of 0.63 for the AUC (95%CI 0.50 to 0.77, p = 0.07) (Supplementary material 2). Thus, only 63% of participants were correctly classified according to CAI status using ‘normalized fibular position’ as the predictor alone. Moreover, the lack of statistical significance of the AUC could indicate that this finding is simply due to chance. The positive and negative likelihood ratios of 1.53 and 0.56 (respectively) do not provide a strong indication for ruling CAI in or out in these individuals, further suggesting that normalized fibular position alone is not an appropriate sole predictor of CAI [30,31]. Therefore, utilization of normalized fibular position measures combined with other clinical findings, might be helpful in identifying people with CAI.
Future research should investigate whether lateral X-ray findings of fibular position may effectively be used in determining the appropriate application of MWM techniques in rehabilitating CAI. Potentially the practitioner could choose whether or not to apply MWM as a treatment for the client based on the amount of displacement. Further, they could also potentially choose the direction of the MWM glide so as to reverse the evident direction of positional displacement. Whether MWM treatment actually reverses fibular displacement on imaging may also merit investigation using the method employed in this study. However, the clinical utility of this method should consider the ease of obtaining an accurate X-ray image and the time spent on taking the fibular position measures. It might also be interesting to investigate whether there is a difference in this measure when normalization is performed using bodyweight given the potential for bodyweight to influence relative bone position [32]. Additionally, the inclusion of a non-weight-bearing group would help determine whether fibular displacement was similarly evident in a non-weight-bearing position. Further, the influence of various ankle positions could be worthy of future investigation. Finally, it would be interesting to measure fibular displacement of the other ankle of people with CAI to explore whether the fibular position was present before the injury or if it resulted from the injury.
Limitations
First, although every effort was made to minimize axial rotation of the lower limb during radiographs, possible rotation of the tibia and fibula may have introduced minor variability in the fibular positional measurements. Second, a priori sample size estimation was not conducted for the ROC analysis because it was a planned but secondary objective. Third, the study was not powered to explore weight-bearing fibular position in subgroups (mechanical and functional instability) of CAI, and thus the potential for heterogeneity of the study sample may have influenced the results. Fourth, in approximate positioning of the knee of the non-imaged limb (slightly flexed, representing mid-stance of the gait cycle) some variability may have been introduced, and in future researchers should consider standardizing this. Fifth, blinding of the radiographer to participant group allocation may have strengthened the internal validity of the study. Finally, the cross-sectional design of the study precludes any cause and effect relationship being ascribed to the fibular positional difference.
Conclusion
As a conclusion, an posteriorly positioned distal fibula in relation to the tibia was observed in people with CAI compared with healthy controls. This fibular positional difference may contribute to the persistence and recurrence of pain and dysfunction in some cases of CAI. Weight-bearing lateral radiographic measurements of fibular position can be performed reliably and reproducibly. However, the low specificity and sensitivity utility scores for normalized fibular position indicate that it has very little ability to predict CAI alone.
Supplementary Material
Biographies
Dr Weerasekara is an early career researcher with a background of a physiotherapist at The University of Newcastle and also affiliated with the University of Peradeniya, Sri Lanka as a lecturer.She is a recipient of highly competitive two scholarships; International Postgraduate Research Scholarships (IPRS) and Australian Postgraduate Awards (APA) of The University of Newcastle. Dr Weerasekara supervises honours and PhD candidates at the Physiotherapy discipline of The University of Newcastle. She has strong collaborations nationally and internationally including the Cochrane network. Her main area of research focus to date has been ankle and chronic diseases, chronic pain, systematic reviews, and scoping reviews.
Dr Peter Osmotherly is an academic physiotherapist and epidemiologist employed as a Senior Lecturer in the School of Health Sciences at The University of Newcastle, Australia. With 30 years of post-professional experience in physiotherapy, Peter Osmotherly has researched and published widely in this field with a focus on spinal disorders. Combining clinical perspectives in the assessment of dysfunction with epidemiological and statistical methods, his published work has encompassed areas from clinical testing to occupational musculoskeletal health disorders. To date, he has produced 6 textbook chapters, 92 peer reviewed publications in academic journals and over 100 conference publications.
Suzanne Snodgrass is Associate Professor in Physiotherapy at The University of Newcastle, Australia. She entered academia after 10 years of clinical practice in musculoskeletal physiotherapy, initially in USA where she completed her entry-level physiotherapy degree at the University of North Carolina-Chapel Hill. Her research investigates the mechanisms that contribute to musculoskeletal pain, with a focus on idiopathic and work-related neck pain, alongside treatments to improve pain and movement dysfunction. She has been recognised with several research and teaching awards, and takes an active role in the profession of physiotherapy, having served on four national or international scientific conference committees since 2007. Associate Professor Snodgrass currently works in a traditional academic role balancing research, teaching and service.
John Tessier is a lecturer in Diagnostic Radiography and has been a radiographer for over 30 years, having completed his Diploma Diagnostic Medical Radiography in 1987. He holds a Graduate Certificate in Tertiary Teaching (University of Newcastle), a Diploma of Business (Frontline Management) and a Master of Philosophy (Medical Radiation Science). John has worked in senior management positions in the private radiology sector and has been involved in the training of staff, in particular with regards to computed tomography (CT).John has been the recipient of teaching awards including the Australian Learning and Teaching Council (ALTC) Citation for Outstanding Contributions to Student Learning (2011). With in a keen interest in the professional placement component of undergraduate education John has twice been awarded the University of Newcastle, Faculty of Health and Medicine, Work Integrated Learning (WIL) Staff Member of the Year (2011 & 2016). John has been awarded the University of Newcastle, Faculty of Health and Medicine International Collaborations Staff Excellence Award in 2012 for his work with students from Singapore upgrading their qualifications from diploma to degree. John maintains a strong interest in collaborations internationally and is currently working with the Shanghai University of Medicine and Health Sciences, China.
Professor Rivett is a former Head of School of Health Sciences and Foundation Professor of Physiotherapy at The University of Newcastle, Australia. He is Vice-President of the Australian Physiotherapy Association and immediate-past President of the Physiotherapy Council of New South Wales, and former National Chairman of Musculoskeletal Physiotherapy Australia. He has been awarded Honoured Membership of Musculoskeletal Physiotherapy Australia, and also Honorary Membership of the Mulligan Concept Teachers Association for his contributions to research.Professor Rivett is co-author of the best-selling text ‘Clinical Reasoning in Musculoskeletal Practice (2nd edn.)’, and also co-author of the texts ‘Mobilisation with Movement: The Art and the Science’ and ‘The Mulligan Concept of Manual Therapy: Textbook of Techniques’. His research interests include the benefits and risks of manual therapy in the cervical spine and clinical reasoning in musculoskeletal practice. He has published 150 peer-reviewed scientific papers and many invited book chapters in prestigious texts, as well as supervised 30 PhD and other higher degree research candidates. Professor Rivett has delivered numerous keynote presentations at conferences nationally and internationally, including the prestigious Geoffrey Maitland Oration.
Disclosure statement
Darren A. Rivett is an honorary member of the Mulligan Concept Teachers Association. The other authors declare that they have no competing interests.
Supplementary material
Supplemental data for this article can be accessed here.
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