Translate this page into:
Rotation-related sports players demonstrate rotation-type lumbar spondylolysis fracture angle and decreased hip internal rotation range of motion
∗Corresponding author: Hideaki Nagamoto. nagamoto@med.tohoku.ac.jp
-
Received: ,
Accepted: ,
This article was originally published by Reed Elsevier India Pvt. Ltd. and was migrated to Scientific Scholar after the change of Publisher.
Abstract
Abstract
Relationship between sports and spondylolysis fracture angle (SFA), and hip internal rotation range of motion (IR ROM) between the sports groups among athletes with spondylolysis were investigated. Sports requiring repeated rotation of the trunk and hips during most aspects of the activity was defined as rotation-related sports (RRS). The SFA was defined as rotation-type or horizontal-type by using the axial view of the CT scan. Percentage of rotation type and SFA of the non-dominant side for RRS group was significantly greater than those of non-RRS group. Hip IR ROM of RRS group was significantly smaller than that of non-RRS group.
Level IV.
Keywords
Lumbar spondylolysis
Rotation-related sports
Spondylolysis fracture angle
Hip internal rotation range of motion
1 Introduction
Low back pain among youth athletes is a major concern as 28–64% of athletes have experienced it until the age of 16.1–4 There is a high prevalence of low back pain among athletes participating in sports, which requires repeated rotation of the trunk and hips to perform.5–7 These specific sports are generally called rotation-related sports (RRS), which include baseball, softball, badminton, tennis, judo, and volleyball.8–10
Lumbar spondylolysis is a stress fracture of the pars interarticularis and is one of the causes of low back pain among the athletes.11,12 Although the incidence varies depending on ethnics, sex, or sports activity, it has been reported to frequently occur in athletes,13 with a 10–20% higher incidence than in non-athletes.14 Lumbar spondylolysis is caused by repetitive extension and rotational loading to the pars interarticularis during the growth period,8,15–17 and the increase in mechanical stresses during sports activities affects the incidence as a result.8 Spondylolysis is more likely to occur in RRS, as they have high rates of angular velocity during rotational motion, such as the swinging motion in baseball.8,13,18 To perform certain motions in any sports activity, proper trunk motion is essential for the transfer of kinetic energy from the lower extremity to the upper extremity.19,20 The spine must have an appropriate movement in order to transfer the kinetic energy properly.21 In addition, the hip joint is also reported to play an important role in transferring of the forces from the lower extremity through the spine. Due to its proximity to the spine, it is closely related to the kinetic chain.9,22 However, players with a breakdown of the kinetic chain create excessive loads on the joints or muscles, resulting in degenerative and irreversible changes. In the lumbar spine, these changes are likely to occur in the facet joints, given that they are primary load-bearing structures of the lumbar spine.
As stated above, since the hip joint and lumbopelvic region are anatomically proximate, many investigators have reported the relationship between hip joint mobility and low back pain.9,10,22–25 Limited and asymmetrical hip rotation has been reported among athletes with lower back pain.9,10,25 Nevertheless, as the trunk twist motion is mostly contributed to by the motion of the hips,24 limitation of the hip rotation may be related to the fracture line of the spondylolysis.
Spondylolysis can be divided into two groups based on the fracture lines: coronally oriented fracture lines caused by extension loading, and sagittally oriented fracture lines caused by rotational loading.8 There have been no reports regarding the relationship between RRS, spondylolysis, hip rotation, and spondylolysis fracture lines. Therefore, this study aimed to reveal the relationship between: 1) participation in sports and spondylolysis fracture angle (SFA), and 2) to compare the hip IR ROM between the sports groups. We hypothesized that athletes participating in RRS will show greater SFA and decreased hip IR ROM compared to athletes participating in non-RRS.
2 Subjects and methods
2.1 Subjects
This study was an observational study and was approved by the institutional review board of the authors’ institution (IRB number 1–13). All procedures for this study were conducted in accordance with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. A total of 100 sport-participating athletes, who visited our outpatient clinic from April 2016 to March 2019 and were diagnosed with spondylolysis of the lumbar spine were retrospectively evaluated for this study. The participants were interviewed to understand their participation in sports as well as their level and intensity (frequency of practices and games). None of the participants had ceased sports at the time of the final visit to the outpatient clinic. All the participants were physically examined by the senior author, which was followed by plain radiographs, computed tomography (CT), and magnetic resonance imaging (MRI). The staging of the spondylolysis was defined according to the past reports.26,27 Early and progressive stage spondylolysis was defined by a case with high intensity change of the pedicle on T2-weighted image and invisible fracture line or hairline crack visible in the pars. Participants were excluded from the evaluation if the spondylolysis was in the early stages or the SFA was unmeasurable by CT. Participation in sports was confirmed, as well as the sports that required repeated rotation of the trunk and hips during most aspects of the activity. These sports were defined as RRS.8,9 Participants were divided into two groups according to their type of sports: RRS group and non-RRS group. Besides physical examination, dominant side hand or foot, level of spondylolysis and its side, SFA, and bilateral hip IR ROM were also investigated. The dominant side of the hand was defined by the hand which the player uses to throw the ball or an opponent, to swing the racket, or to strike the ball. The dominant side of the foot was defined by the foot which the player primarily kicks the ball or ground.
2.2 Imaging and measurement
SFA was measured using the axial view of the CT scan according to previous reports.26,28 CT images were obtained using the reverse-gantry angles on the plane axial to the vertebrae. The images were filmed at 350 to 1600 window width and 50 to 600 window level with slice thickness intervals of 0.5 mm (Aquillion Prime SP, Canon, Tokyo, Japan). A line parallel to the posterior cortex of the vertebral body at the level of spondylolysis was defined and a second line tangential to the defect was drawn. The angle between them was measured, and it was defined as a rotation-type fracture if the angle was over 20°, and a horizontal-type fracture if it was under 20°8,29 (Fig. 1). X-ray and MRI were routinely performed for the diagnosis of spondylolysis; however the obtained data were not used for this study.
2.3 Physical examination
For the hip IR ROM measurement, participants were instructed to lie supine on a table and were evaluated with their hips and knees flexed at 90° using a standard goniometer. The subject's pelvis was stabilized by the assistant while the observer held the subject's lower leg and internally rotated the hip passively. The stable arm of the goniometer was aligned with the body axis, and the mobile arm was aligned to the shaft of the tibia. The angle of the position was then recorded. The measurement was undertaken by a senior author (H.N.).
2.4 Patient and public involvement
None of the patients or public was involved in the study design, or conduct, or reporting, or dissemination plans of our research.
2.5 Statistical analysis
All statistical analyses were performed using JMP Pro 15 software (SAS Institute, Cary, NC, USA). The relationship between participation in sports and fracture type was analyzed using chi-square test, while the relationship between participating sport groups and hip IR ROM was analyzed using ANOVA. Results were considered statistically significant if the P values were less than 0.05.
3 Results
A total of 88 pedicles from 54 sport-participating athletes met the inclusion criteria and were evaluated. The participants’ average age was 15.3 ± 1.7 years (range, 10–21 years) and there were 44 male and 10 female. The demographic data of the participants are shown in Table 1. The stage of spondylolysis for all the pedicles were in the terminal or progressive stage. All the participants belonged to sports teams from the school they attended or sports clubs in the community where they attended practice for more than five times a week.
| Age | 15.3 ± 1.7 years | |
| Male | 44 | |
| Female | 10 | |
| Competition level | Professional | 2 |
| High school | 28 | |
| Junior high school | 22 | |
| Primary school | 2 | |
| Laterality | Right | 50 |
| Left | 4 | |
| Side of spondylolysis | Dominant side | 9 |
| Nondominant side | 11 | |
| Bilateral | 34 | |
3.1 Participant characteristics
Thirty-four participants (65%) were classified into the RRS group and 20 participants (35%) were classified into the non-RRS group. Participants from the RRS group were divided as follows: 26 from baseball, 3 from volleyball, 2 from badminton, 2 from judo, and 1 from tennis. The non-RRS group included 11 from soccer, 5 from basketball, and 4 from track and field. The dominant side was right in 50 participants overall (93%) and left in 4 of the total participants (7%). Spondylolysis was observed in the nondominant side in 11 participants (20%), the dominant side in 9 participants (17%), and bilaterally in 34 participants (63%). Spondylolysis levels of L5, L4, and L3 of the dominant side were 59%, 33%, and 8%, respectively, and those of the nondominant side were 59%, 31%, and 10%, respectively. Among the 34 pedicles with bilateral spondylolysis, 11 pedicles showed different fracture type. Four pedicles from non-RRS players all showed rotation-type on the dominant side and horizontal type on the nondominant side. For 7 pedicles from RRS players, all the pedicles showed rotation-type on the nondominant side and horizontal type on the dominant side, except for 1 pedicle which showed rotation-type on the dominant side and horizontal type on the nondominant side. Six participants showed spondylolysis in 2 levels. None of the participants showed more than 3 levels of spondylolysis.
3.2 Relationship between SFA and sports
The prevalence of the rotation-type fracture among all the pedicles on the nondominant side were statistically significant between the RRS group and non-RRS groups, as 74% of fractures were classified as a rotation-type in the RRS group, whereas only 13% were classified as such in the non-RRS group (P < 0.001). SFA on the nondominant side of the RRS group was 27.3 ± 2.9° (95% CI, 21.3–33.2°) and that of the non-RRS group was 11.8 ± 3.4° (95% CI, 4.8–18.7°), which was statistically significant (P = 0.001) (Fig. 2). In contrast, SFA on the dominant side between the RRS group (17.5 ± 2.8°, 95% CI, 11.8–23.3°) and non-RRS group (19.2 ± 2.9°, 95% CI, 13.3–25.1°) showed no significant difference (Fig. 3).
3.3 Hip IR ROM between the groups
Hip IR ROM of the participants in RRS group was 26.7 ± 2.0° (95% CI, 22.8–30.7°) on the dominant side and 26.3 ± 2.2° (95% CI, 22.0–30.6°) on the nondominant side. Those of the non-RRS group was 43.3 ± 4.3° (95% CI, 34.7–52.0°) on the dominant side and 43.6 ± 4.7° (95% CI, 34.5–53.3°) on the nondominant side. The hip IR ROM of the dominant and the nondominant sides was statistically significant between the RRS group and non-RRS groups (P = 0.001, and 0.001, respectively) (Figs. 4 and 5).
4 Discussion
Our data showed that the prevalence of rotation-type fractures on the nondominant side in the RRS group was higher than those who participated in non-RRS. Hip IR ROM was significantly smaller on both the dominant and nondominant sides among the participants of the RRS group compared to those in the non-RRS group.
4.1 Fracture type and hip IR ROM
The RRS group showed a higher percentage of the rotation-type fracture on the nondominant side than those in the non-RRS group. As it has been reported that rotational loading causes sagittally oriented fractures, it can be assumed that the trunk and lumbar spine of the participants in the RRS group tend to sustain a rotational stress compared to those in the non-RRS group. With the limitation of the hip IR in both the dominant and nondominant sides, trunk rotation may increase as a compensation mechanism, resulting in increased mechanical stress at the facet. Since RRS requires repeated rotation motion of the hip and trunk, spondylolysis of rotation-type fractures in the RRS group may have been caused by more frequent trunk rotations due to bilaterally restricted hip IR ROM. Decreased hip IR ROM has been reported among athletes participating in RRS. Murray et al. found that amateur golfers with low back pain showed decreased hip IR ROM of the lead leg, which equates to the nondominant side in our study, compared to the controls.29 Vad et al. reported that professional tennis players and golfers with low back pain displayed decreased hip IR ROM of the lead leg compared to the non-lead leg, which was not present in players without low back pain.30,31 Baseball players have also been reported to have restriction in hip ROM.32 The results of our study agree with these previous reports, and the limitation of hip IR ROM may have a deep relationship with the development of spondylolysis among athletes competing in RRS.
4.2 RRS (baseball) and spondylolysis
It has been reported that spondylolysis are more likely to occur in the nondominant side.8,23,33 Sairyo et al. have revealed by means of biomechanical testing, using a three-dimensional finite element model, that during lumbar extension and axial rotation to the contralateral side, higher stresses were observed at the pars interarticularis.8 They concluded that extension and rotation may be important motions for inducing lumbar spondylolysis. Among RRS baseball is one of the most popular sports (also shown in our population of participants), and several studies have revealed rotation and extension modes during the pitching motion. During the pitching motion, maximum trunk rotation is reported to occur before ball release, approximately at the foot contact phase, and angular acceleration begins after the foot contact phase.34 It was also shown that most pitchers spent almost half of the pitch cycle in over 30° of lumbar extension.35 During the foot contact phase, the trunk was externally rotated and at the maximal externally rotated position of the throwing arm, the trunk was internally rotated.36 From these previous reports, it can be concluded that trunk rotation and extension occur in the early phase of the pitching motion, especially to the throwing side from the cocking phase to the foot contact phase, resulting in increased mechanical stress on the contralateral facet, which would occur on the nondominant side. If bilateral hip IR ROM limitation is present, increased compensatory motion may occur in the lumbar region in athletes participating in RRS, which results in a rotation-type fracture line in the pars interarticularis of the non-throwing side. Future studies should be undertaken to confirm the mechanical stress of the facet and pars interarticularis during pitching and to reveal which pitching phase causes the highest stress to the pars interarticularis of the non-throwing side.
4.3 Hip IR ROM and low back pain among RRS
Decreased hip IR ROM among athletes participating in RRS with low back pain has been advocated in the past.8–10 Judo is a physically demanding sport that requires high frequency of rotation movements throughout multiple segments.37 As such, it is regarded to be one of RRS.8 Tak et al. have reported that lower hip IR ROM of the nondominant leg is significantly related to low back pain among male adult judokas.25 In addition, Almeida et al. have mentioned that judokas with a history of non-specific low back pain exhibited a significant reduction in hip IR ROM compared to those with no history of low back pain, especially in nondominant side.37 The results of our study coincide with these past reports and restricted hip IR ROM of the nondominant side may relate to non-specific low back pain, especially in lumbar spondylolysis. To the best of our knowledge, there were no reports regarding the relationship between low back pain and hip rotation IR ROM for volleyball, and badminton. The relationship between low back pain or lumbar spondylolysis and hip rotation among volleyball and badminton may have to be revealed to strengthen the quality of the results of our study.
4.4 Limitations
This study has several limitations. First, selection bias may have affected the results. The prevalence of spondylolysis among each sports is unknown. Increasing the subjects and analyzing in respective sports may resolve the issue. Also, the prevalence of symptomatic spondylolysis is unknown and by including the asymptomatic cases, the results may have differed. However, as the study was carried out as an observational study at the outpatient clinic, including them was impossible as they do not visit the clinic if they were asymptomatic. Defining the sports to RRS or non-RRS sport may have also affected the results. Nevertheless, we defined the sports according to the previous reports.8–10 The definition of the sports may have to be discussed in the future studies. Second, several positions could have been included among the baseball players. Pitchers are more likely to suffer from lumbar spondylolysis than players in other positions.33 The relationship between the positions may be more elucidated with a larger number of participants. Third, unilateral and bilateral fractures were not analyzed separately. Bilateral fractures of the pars interarticularis are commonly found in children and adolescents.38 As the participants were divided into two groups, the number of pedicles might have been limited to small numbers and thus our results may not be generalized for all athletes with spondylolysis. To make the effect as small as possible and reflect laterality, analysis was performed according to the dominant hand or foot. Fourth, SFA was measured from the axial view of spondylolysis. Saifuddin et al. measured the SFA from an axial view,28 whereas Fujii et al. measured SFA in a plane parallel to the pars interarticularis.26 The plane that truly reflects the fracture type is unknown. Therefore, if the image was taken on the plane parallel to the pars interarticularis, the angle of the imaging plane will differ depending on each participant or fracture line. Thus, we speculated that the measurement plane of the angle cannot be standardized, which may affect the measurement of the SFA. From this standpoint, measurements were carried out using the axial view.28 Fifth, the results of hip IR ROM may differ by measurement method. Currently, measuring with the use of a goniometer or inclinometer is recommended, but the optimal measurement of the hip is reported to be controversial.39 However, the measurement of hip IR ROM with hips and knees flexed at 90° is reported to minimize the standard error of measurement, and using a single examiner can also decrease the measurement variability.40,41 Since our study evaluated the hip IR ROM with the participants' hips and knees flexed at 90° by using a standard goniometer, we suppose it was able to increase the reliability of the measurement. Lastly, participants may have played in several sports. Considered sports were chosen from the answers given during the interview at the outpatient clinic. As it is practically impossible to reveal each participant's daily activities or extra-curricular activities, whether the participant took part in another sports or not had to be ignored. The most important finding of this study was that the fracture type of spondylolysis may differ according to the type of sports and that this may be significantly associated with the hip ROM. Spondylolysis mostly responds to conservative treatment, and the basic concept is rigid immobilization along with appropriate physical therapy. Idendifying the mechanisms and development of spondylolysis may lead to an effective immobilization method depending on the fracture type. Furthermore, identifying the related physical factors, regaining proper motion through appropriate physical therapy, and accomplishing efficient energy transfer are important not only to early return to play, but also to prevent recurrence and improve performance.
5 Conclusion
Athletes performing rotation-related sports are more prone to rotation-type spondylolysis with fracture angles on the nondominant side than those participated in non-rotation-related sports. A decreased ROM of bilateral hip internal rotation may have an association with spondylolysis fracture angle.
Funding
This research did not receive any specific grant from funding agencies in the public, commercial, or non-for-profit sectors.
Author contributions
H.N: Conceptualization, Methodology, Formal analysis, Investigation, Resources, Writing- Reviewing and Editing, Visualization, Supervision.
M.A.: Conceptualization, Methodology.
Y.K.: Conceptualization, Methodology, Formal analysis, Writing- Original draft preparation.
R.K.: Investigation, Resources.
M.T.: Investigation, Resources.
A.O. Investigation, Resources, Supervision.
References
- Cross-sectional study of the isokinetic muscle trunk strength among school children. Spine. 1993;18(9):1199-1205.
- [Google Scholar]
- Physical activity and low-back pain in schoolchildren. Eur Spine J. 2008;17:373-379.
- [Google Scholar]
- Low back pain in childhood and adolescense: a cross-sectional study in Niigata City. Eur Spine J. 2008;17:1441-1447.
- [Google Scholar]
- Risk factors for low back pain in a cohort of 1389 Danish school children: an epidemiologic study. Eur J Spine. 1999;8:444-450.
- [Google Scholar]
- MRI findings in the lumbar spine of asymptomatic, adolescent, elite tennis players. Br J Sports Med. 2007;41(11):836-841.
- [Google Scholar]
- Lumbar intervertebral disk degeneration in athletes. Am J Sports Med. 2009;37(1):149-155.
- [Google Scholar]
- Spondylolysis fracture angle in children and adolscents on CT indicates the fracture producing forces vector: a biomechanical rationale. Internet J Spine Surg. 2004;1(2):1-6.
- [Google Scholar]
- Hip rotation range of motion in people with and without low back pain who participate in rotation-related sports. Phys Ther Sport. 2008;9(2):72-81.
- [Google Scholar]
- Relationship between the hip and low back pain in athletes who participate in rotation-related sports. J Sport Rehabil. 2009;18(1):60-75.
- [Google Scholar]
- Fatigue fracture: the basic lesion is inthmic spondylolisthesis. J Bone Joint Surg Am. 1975;57(1):17-22.
- [Google Scholar]
- Three successive stress fractures at the same vertebral level in an adolescent baseball player. Am J Sports Med. 2003;31(4):606-610.
- [Google Scholar]
- Incidence and etiology of lumbar spondylolysis: a review of the literature. J Orthop Sci. 2010;15:281-288.
- [Google Scholar]
- The influence of the spine on the shoulder in the throwing athlete. J Back Musculoskelet Rehabil. 1996;7:5-17.
- [Google Scholar]
- Lumbar facet joint and intervertebral disk loading during simulated pelvic obliquity. Spine J. 2013;13(11):1581-1589.
- [Google Scholar]
- The prevalence of spondylolysis in the Spanish elite athlete. Am J Sports Med. 2000;28(1):57-62.
- [Google Scholar]
- Hitting a baseball: a biomechanical description. J Orthop Sports Phys Ther. 1995;22(5):193-201.
- [Google Scholar]
- Pelvis and torso kinematics and their relationship to shoulder kinematics in high-school baseball pitchers. J Strength Condit Res. 2010;24(12):3241-3246.
- [Google Scholar]
- Thoracolumbar range of motion in baseball pitchers and position players. Inj J Sports Phys Ther. 2013;8(6):777-783.
- [Google Scholar]
- Hip muscle imbalance and low back pain in athletes: influence of core strengthening. Med Sci Sports Exerc. 2002;34(1):9-16.
- [Google Scholar]
- Lumbar facet joint and intervertebral disk loading during simulated pelvic obliquity. Spine J. 2013;13(11):1581-1589.
- [Google Scholar]
- The Hip-spine connection: understanding its importance in the treatment of hip pathology. Orthopedics. 2015;38(1):49-55.
- [Google Scholar]
- Judokas with low back pain have lower flexibility of the hip-spine complex: a case-control study. Phys Ther Sport. 2020;45(1):30-37.
- [Google Scholar]
- Union of defects in the pars interarticularis of the lumbar spine in children and adolescents. The radiological outcome after conservative treatment. J Bone Joint Surg Br. 2004;86-B(2):225-231.
- [Google Scholar]
- Conservative treatment of lumbar spondylolysis in childhood and adolescense. The radiological signs which predict healing. J Bone Joint Surg Br. 2009;91-B:206-209.
- [Google Scholar]
- Orientation of lumbar pars defects. Implications for radiologic detection and surgical management. J Bone Joint Surg Br. 1998;80-B:208-211.
- [Google Scholar]
- The relationship between hip rotation range of movement and low back pain prevalence in amateur golfers: an observational study. Phys Ther Sport. 2009;10(4):131-135.
- [Google Scholar]
- Low back pain in professional golfers: the role of associated hip and low back range-of-motion deficits. Am J Sports Med. 2004;32(2):494-497.
- [Google Scholar]
- Hip and shoulder internal rotation range of motion deficits in professional tennis players. J Sci Med Sport. 2003;6(1):71-75.
- [Google Scholar]
- Regional independence of the hip and lumbo-pelvic region in Division II collegiate level baseball pitchers: a preliminary study. Int J Sports Phys Ther. 2015;10(1):1-12.
- [Google Scholar]
- Relationship between throwing side and laterality of lumbar spondylolysis in baseball players. J Spine Res. 2020;11(1):22-26.
- [Google Scholar]
- Trunk axial rotation in baseball pitching and batting. Sports BioMech. 2013;12(4):324-333.
- [Google Scholar]
- Lumbar hyperextension in baseball pitching: a potential cause of spondylolysis. J Appl Biomech. 2018;34(6):429-434.
- [Google Scholar]
- The association among trunk rotation, ball velocity, and the elbow varus moment in collegiate-level baseball pitchers. Am J Sports Med. 2019;47(12):2816-2820.
- [Google Scholar]
- Comparison of hip rotation range of motion in judo athletes with and without history of low back pain. Man Ther. 2012;17(3):231-235.
- [Google Scholar]
- Lumbar spondylolysis in children and adolescents. J Bone Joint Surg [Br]. 1995;77-B:620-625.
- [Google Scholar]
- Standardised measurment of physical capacity in youg and middle-aged active adults with hip-related pain: recommendations from the first International Hip-related Pain Research Network (IHiPRN) meeting, Zurich, 2018. Br J Sports Med. 2020;54:702-710.
- [Google Scholar]
- Is lower hip range of motion a risk factor for groin pain in athletes? A systematic review with clinical applications. Br J Sports Med. 2017;51:1611-1621.
- [Google Scholar]
- Validity and test-retest reliability of manual goniometers for measuring passive hip range of motion in femoracetabular impingement patients. BMC Muscoskel Disord. 2010;11:194.
- [Google Scholar]