|Year : 2020 | Volume
| Issue : 2 | Page : 87-92
Is genu varum a risk factor for the prevalence and severity of achilles tendinopathy? A cross-sectional study of Nigerian elite track and field athletes
Ayoola Ibifubara Aiyegbusi, Bosede Abidemi Tella, Ganiyat Adebanke Sanusi
Department of Physiotherapy, College of Medicine, University of Lagos, Lagos, Nigeria
|Date of Submission||15-Nov-2019|
|Date of Decision||28-Nov-2019|
|Date of Acceptance||21-Jan-2020|
|Date of Web Publication||11-Apr-2020|
Dr. Ayoola Ibifubara Aiyegbusi
Department of Physiotherapy, College of Medicine, University of Lagos, Lagos
Source of Support: None, Conflict of Interest: None
Background: Achilles tendinopathy (AT) is one of the most frequently reported ankle and foot overuse injuries. Prior studies have reported altered biomechanical variables of the lower limb as risk factors for the prevalence and severity of AT in athletes, especially in Caucasians, but there are few reports on African elite athletes. Because it is established that anthropometric and biomechanical values vary with racial disposition, this study was designed to investigate the association between selected physical and biomechanical variables of the lower limb and the prevalence and severity of AT in Nigerian elite track and field athletes. Subjects and Methods: Eighty-five elite Nigerian track and field athletes participated in this cross-sectional study. Biomechanical variables of Q-angle, tibial torsion, limb-length discrepancy (LLD) and foot posture index (FPI) were evaluated using standard procedures. The presence of AT was confirmed with ultrasonography and clinical assessments, whereas the severity was evaluated with VISA-A questionnaire. Inferential statistics of Chi-square was used to determine the association between prevalence of AT and the biomechanical variables. Results: The prevalence of AT was 15.3%, made up of participants who tested positive to both clinical test and ultrasound scan. There was no significant association between AT and LLD, tibial torsion and FPI. Most of the participants with AT had genu varum, which was significantly associated with both the prevalence and severity of AT. Conclusion: It was concluded that genu varum had a significant association with both the prevalence and severity of AT in elite Nigerian track and field athletes.
Keywords: Achilles tendinopathy, biomechanical variables, genu varum
|How to cite this article:|
Aiyegbusi AI, Tella BA, Sanusi GA. Is genu varum a risk factor for the prevalence and severity of achilles tendinopathy? A cross-sectional study of Nigerian elite track and field athletes. Niger Postgrad Med J 2020;27:87-92
|How to cite this URL:|
Aiyegbusi AI, Tella BA, Sanusi GA. Is genu varum a risk factor for the prevalence and severity of achilles tendinopathy? A cross-sectional study of Nigerian elite track and field athletes. Niger Postgrad Med J [serial online] 2020 [cited 2020 Jul 4];27:87-92. Available from: http://www.npmj.org/text.asp?2020/27/2/87/282314
| Introduction|| |
Achilles tendinopathy (AT) is one of the most frequently reported ankle and foot overuse injuries constituting about 30%–50% of all activity-related chronic tendon disorders. It is associated with clinical symptoms of pain, swelling, discomfort in the tendon and failure to regain full function.,
Biomechanics of the lower limbs which is the complex interplay of the musculoskeletal and nervous system that allows for postural alignment and functional movement of the lower-limb segments is a factor to consider in AT. Sex-related differences in lower-limb biomechanics among athletes have been reported in some studies although disparities occur in results reported as regards how this translates to a high incidence of injuries among male or female athletes.,,
Studies have shown the effect of altered biomechanics of the lower limb in athletes, and a number of studies have been able to provide information on the association between lower-limb biomechanics and the prevalence of AT among Caucasians, but it is also known that anthropometric and biomechanical values vary with racial disposition., There is a dearth of studies on athletes of African extraction; hence, this study was designed to determine the association between selected physical characteristics and biomechanical variables of the lower limb and the prevalence of AT in elite track and field athletes. This study was undertaken to determine other potential risk factors asides overuse, which may contribute to the prevalence and severity of AT in athletes; therefore, it was designed to investigate the association between selected physical and biomechanical variables of the lower limb and the prevalence of AT in Nigerian elite track and field athletes.
| Subjects and Methods|| |
A total of 85 professional track and field athletes recruited from three different stadia in Lagos, Nigeria, participated in this study. Athletes who were 18 years and above and specialised in one or more of running, long jump and high jump were included in the study. Athletes who had previously been diagnosed of other lower-limb pathology or have undergone any previous surgery to the lower limb were excluded from the study. The sample size calculation returned a minimum sample size of 77 participants, though a total of 85 participants were recruited for the study. Ethical approval was sought and obtained from the institutional health research and ethics committee.
| Methods|| |
Ethical approval was sought and obtained from the Health Research and Ethics Committee of the College of Medicine, University of Lagos, with registration number: CMUL/HREC/09/18/418 (25th October 2018). This was a cross-sectional study and participants were recruited using a convenience sampling technique. They were assessed for the presence of AT using ultrasound imaging with a portable ultrasound machine with a transducer probe of frequency 10–15 MHz (Siemens Acuson; Siemens Medical Solutions, Inc., Malvern, Pennsylvania). The ultrasound scan was also used to rule out other pathology of the ankle and ascertain the presence of inflammation or degeneration of the Achilles tendon. Both the procedure and interpretation of the scan were done by a musculoskeletal sonographer. Athletes who had no ultrasonographic indication of AT were separated from those whose ultrasound scan showed signs of AT. Those who tested positive to the ultrasound scan were assessed for their physical characteristics and biomechanical variables in addition to assessment with the Royal London Hospital test to distinguish between participants with symptomatic and asymptomatic AT. Those who had clinical symptoms were further assessed with VISA-A questionnaire to determine the severity.
Athletes who met the inclusion criteria were approached with details of the procedure and purpose of the research. Informed consent was then sought and obtained from the participants. Demographic information such as sex, age, sport specialisation and length of participation in sorting activities was documented with measurements of physical and biomechanical variables. The participants' weight and height were duly evaluated, and the body mass index (BMI) was calculated.
Participants were positioned on a plinth in prone lying position with the foot and ankle adequately exposed. The foot was positioned such that it was in slight dorsiflexion dangling at the edge of the plinth. The ultrasound scan was carried out by a musculoskeletal sonographer. The tendon was assessed for focal thickening and hypoechoic portion of the Achilles tendon.
Royal London Hospital test
The athletes were in prone lying position with the foot and ankle adequately exposed. The Achilles tendon was palpated for pain and tenderness and the region of pain along the tendon was marked. The athlete was then asked to fully dorsiflex the foot, and the point of pain previously reported was palpated again. A significant reduction of pain in the same region on dorsiflexion confirmed the presence of AT.
This was used to determine the severity of AT in symptomatic participants. The athletes were asked to respond to all the eight questions on the questionnaire which was read and explained to them. The questions inquired about pain, stiffness and function. Points were allocated to each question appropriately. All points were added and scored out of 100, where lower scores indicate greater severity than higher scores. The VISA-A questionnaire had good test–retest (r = 0.93), intra-rater (three tests, r = 0.90) and inter-rater (r = 0.90) reliability as well as good stability when compared 1 week apart (r = 0.81) (Robinson et al., 2001). In this study, the participants were grouped into moderate and severe groups of >70 and <70, respectively.
Foot posture assessment with foot posture index-6
The participants were asked to stand relaxed, looking straight ahead and bearing weight on both the legs. The feet were then examined, and the scores were allocated. The normal value of a foot in neutral position is an aggregate score of between 0 and +5. A score between +6 and +9 indicated a pronated foot, whereas a score between −1 and −4 was attributed to supination of the foot. Foot posture index (FPI) score between −5 and −12 indicated a highly supinated foot and scores above +10 indicated a highly pronated foot. The intra-rater reliability was excellent for left (0.956) and right feet (0.959).
This was measured with participants in prone lying using a goniometer. Tibial torsion of the participants was measured using the thigh–foot angle which measures the angle between the longitudinal axis of the thigh and the longitudinal axis of the foot. The stationary arm of the goniometer was placed along the longitudinal axis of the foot, whereas the moveable arm was rotated to the longitudinal axis of the thigh. A value higher than the normal range of 12°–18° was regarded as external tibial torsion and a lower value as internal tibial torsion.,
The quadriceps angle
This is the angle between the quadriceps tendon and the patellar tendon; it is an index of the vector for the combined pull of the extensor mechanisms and the patellar tendon. This was measured with the participant in standing position by marking the anterior superior iliac spine and the tip of the patella and drawing a line to connect both landmarks along the long axis of the femur. Another longitudinal line was drawn from the mid-patella point to the tip of the patella intersecting with the first line. The angle formed by this intersection was measured with a goniometer. The normal values for Q-angle in standing position among the Nigerian population are 8.9°–14.5° for men and about 18.1°–27.3° for women.
Limb-length discrepancy (LLD) was measured using the direct method with a tape measure. The measurement was taken with the participant in standing position. The real LLD was then measured from the ASIS to the medial malleoli of both lower limbs and the difference, if any, was noted. Values of discrepancy of more than 2.5 cm were noted as significant.
Data were analysed using Statistical Package for the Social Sciences version 20 and summarised using descriptive statistics of mean and standard deviation. Percentages and frequency distribution were represented using tables and charts. Inferential statistics of Chi-square was used to determine the association between prevalence of AT and the selected physical characteristics (age, sex and BMI) and biomechanical variables among track and field athletes.
| Results|| |
A total of 85 track and field athletes participated in this study, of them 56 (65.9%) were male and 29 (34.1%) were female. It was discovered that most of the athletes participated in more than one sport. The highest number of respondents was runners, with 74 (87.1%) athletes participating in sprints and 5 (5.9%) of the runners participating in middle- and long-distance running. Only 1 (1.2%) of the respondents partook in pole-vault, whereas athletes participating in long jump and high jump were 19 (22.4%) and 5 (5.9%), respectively. The prevalence of AT among the athletes was 13 (15.3%), which consisted of participants who tested positive to both clinical test and ultrasound scan. Only 1 (1.2%) participant tested positive to clinical tests but negative to ultrasound scan, whereas all the others 71 (83.5%) were negative for both clinical tests and ultrasound scans. The severity of the condition in the athletes who had clinical symptoms was rated on the VISA-A questionnaire as either moderate (above 70) or severe (below 70) among the thirteen athletes who were positive. Eight (61.5%) of the symptomatic athletes scored below 70 on the scale, whereas 5 (38.5%) athletes scored above 70. There was no significant association between the physical characteristics and prevalence of AT as seen in [Table 1]. [Table 2] and [Table 3] show the association between the selected biomechanical variables and the prevalence of AT, whereas [Table 4] and [Table 5] show the association between these selected variables and the severity of the condition.
|Table 1: Association between physical characteristics and prevalence of Achilles tendinopathy|
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|Table 2: Association between Q-angle, tibial torsion and prevalence of Achilles tendinopathy|
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|Table 3: Association between foot posture, limb-length discrepancy and prevalence of Achilles tendinopathy|
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|Table 4: Association between biomechanical variables and severity of Achilles tendinopathy|
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|Table 5: Association between foot posture, limb-length discrepancy and severity of Achilles tendinopathy|
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| Discussion|| |
The purpose of this study was to determine the prevalence and severity of AT among professional track and field athletes and their association with selected physical characteristics and biomechanical variables of the lower limbs.
The prevalence of AT was found to be 15.3% among elite track and field athletes. This was much lower than the prevalence of 21% reported by Aiyegbusi et al., probably because the study population then was recreational athletes, especially the category of “weekend warriors” who occasionally engage in sports activity. In this group of athletes, deconditioning may occur with infrequent use and sudden return to vigorous sporting activity may predispose the individuals to Achilles tendon injury., In addition, increase in awareness about the importance of preventive measures, use of appropriate footwear and protective gears as well as proper sporting techniques on the part of the professional athletes may also be responsible for the lower prevalence.
This study found no significant association between the selected physical characteristics of the athletes and the prevalence of AT. Our results show that physical characteristics had no significant impact on the prevalence of AT, though Franceschi et al. had concluded that BMI and tissue adiposity have a consistent effect on AT. An earlier cross-sectional survey conducted in Poland, however, reported that age and sex had no influence on the profile of AT among professional track and field athletes.
The results of this study demonstrated no significant association between age and prevalence of AT. This agrees with an older study by Maffulli et al., where their findings suggested no association between age and AT. However, contrary to the findings of this study, a study carried out on recreational athletes in this same geographical region reported that age had a significant impact on the prevalence of AT. Although it is expected that age would be an important influence on the physiological degenerative changes, this finding may be due to the fact that professional athletes are more exposed to health-care facilities and preventive programs when compared to recreational athletes who are more likely to suffer from repetitive stress syndrome where injuries are either self-managed or not managed at all. Second, professional athletes are less likely to suffer deconditioning of the tendon unlike recreational athletes as earlier discussed.
None of the biomechanical variables of the lower limb except Q-angle was found to be significantly associated with the prevalence of AT, which underscores the importance of knee joint alignment in the development of AT in this population of sportspersons. This is in line with the findings of Esmaeili et al., that a significant association exists between Achilles tendon pathology and Q-angle among professional sprinters, even as Ilahi and Kohl identified Q-angle and LLD as main factors related to overuse injuries. Interestingly, it is seen from our results that majority of the athletes with tendinopathy had lower than normal Q-angles. A previous study had reported that the normal values for Q-angle in standing position among the Nigerian population are 8.9°–14.5° for men and 18.1°–27.3° for women. Tajdini Kakavandi et al. had concluded in their study that participants with genu varum had increased activity in the gluteus medius muscle. The importance of hip biomechanics in the development of AT in male runners has been reported in a recent study. Franettovich Smith et al. had earlier provided preliminary evidence of altered neuromotor control of the gluteus medius and gluteus maximus muscles in male runners with AT. This is important because poorer gluteal activation has been found to increase hip internal rotation and adduction resulting in pronation which predisposes the runner to developing AT. Our results also show that low Q-angle in the dominant limb was significantly related to the severity of AT and this has been attributed to late and short-term firing of the gluteus medius muscle as reported in an earlier study.
For other biomechanical variables such as LLD, tibial torsion and FPI, most of the athletes presented with normal values, so there was no significant association with both the prevalence and severity of AT. Although it is expected that alignment of the foot and its medial arch height will have a direct impact on the development of AT, it does not appear to be so from the findings of this study. This could be due to proper foot support from appropriate footwear during running and other sporting activities among these elite sportsmen. More importantly, the values used to determine these biomechanical variables are standard values that are peculiar to other climes. This is unlike the Q-angle values which were the results for the evaluation of the normative Q-angle in Nigerians. It is thus advocated that studies be carried that will determine the normal biomechanical variables for Nigerians as this will give a more objective picture of their impact on the prevalence and severity of AT. This is pertinent as it is also known that anthropometric and biomechanical values vary with racial disposition.,
| Conclusion|| |
Based on the results of this study, we conclude that genu varum had a significant association with both the prevalence and severity of AT in elite Nigerian track and field athletes. We therefore recommend routine Q-angle evaluation to assess knee joint alignment in individuals who wish to pursue a career in sports.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]