Official Journals By StatPerson Publication
Table of Content - Volume 9 Issue 2 - February 2019
Hamstrings muscles tightness in adolescences with a thoracic hyperkyphosis: Comparison of muscles flexibility and joint mobility in patients with scheuermann juvenile kyphosis versus postural thoracic hyperkyphosis
P Janusz1*, K Politarczyk1, M. Kozinoga1, T Kotwicki2
1Spine Disorders Unit, Spine Disorders and Pediatric Orthopedics Department, Poznan University of Medical Sciences, 61-654 Poznan, ul. 28.Czerwca 1956r nr 135-147, Poland, 2Spine Disorders and Pediatric Orthopedics Department, Poznan University of Medical Sciences, 61-654 Poznan, ul. 28.Czerwca 1956r nr 135-147, Poland Email: mdpjanusz@gmail.com
Abstract Background: Thoracic hyperkyphosis is classified as non-structural or structural. The Scheuermann’s disease (SD) is one of the most common structural spine hyperkyphosis in adolescents while postural hyperkyphosis (PHK) is non-structural. The tight hamstring muscles (HS) were reported in SD. Aim: The aim of this study was to evaluate the difference in muscles tightness and generalized joint hypermobility between the SD and PHK patients. Material and methods: The study group consisted of 40 SD patients (29 boys and 11 girls) in the age of 13.9 ±1.8 years. The control group consisted of 30 PHK patients (9 boys and 21 girls) in age of 13.0 ±2.1 years. The diagnosis was confirmed radiologically. The following measures were performed in clinical examination: sacral slope, lumbar lordosis, thoracic kyphosis, proximal thoracic kyphosis Th1-Th6, distal thoracic kyphosis Th6-Th12, popliteal angle (PA), fingertip-to-floor test (FTF), modified Thomas test, the gastrocnemius and the pectoralis major muscles flexibility tests. The angles were measured with Saunders digital inclinometer. The occurrence of generalized joint hypermobility (GJH) was evaluated using the Beighton scale. Observations and results: There were no significant differences of the sagittal spine alignment parameters. There were 2 cases of GJH in the PHK patients vs. 0 in SD patients, p=0.4906. The differences between SD patients vs. PHK patients were as follows: PA 51.9 ±8.3° vs. 46.7 ±11.6°, p=0.0262, FTF distance 13.1 ±11.3 vs. 6.8 ±10.1 cm, p=0.0189, Thomas test 57.8 ±6.2° vs. 58.6 ±7.1°, p=0.3205. The decreased flexibility of the pectoralis major and the gastrocnemius muscle was found in 60% vs. 53.3% and in 65% vs. 53.3%, p=0.6253 and p=0.2814, respectively. Conclusions: Patients with Scheuermann`s disease reveal more significant tightness of the hamstring muscles, than patients with postural hyperkyphosis. The generalized joints hypermobility is not common in patients with Scheuerman’s disease. Key Word: Scheuermann’s disease, postural hyperkyphosis, hamstring muscles tightness, generalized joint hypermobility Scheuermann juvenile kyphosis INTRODUCTION Good posture is a state of equilibrium of body segments, in a position of least effort and maximum support1. The most common disturbance of body posture in adolescence concerns the spine sagittal alignment2,3. Thoracic hyperkyphosis (increase in thoracic curve greater than normal range of 40°) is one of prevalent spinal disorders2. Biomechanical analysis reveals that an increase of thoracic kyphosis is associated with significantly higher spinal loads in upright stance. This might accelerate degenerative process within the spine4,6. The disturbances of human posture can be classified as non-structural or structural3. The Scheuermann’s disease (SD) is one of the most common causes of structural spine hyperkyphosis in adolescents7. The prevalence of SD is 0.4%–8% of growing population8,10. In the typical manifestation, the SD is localized in thoracic region of the spine and results in a stiff structural hyperkyphosis10 by wedging of the anterior aspect of vertebral bodies11. The etiology is unclear even if several theories have been published11. One of the hypothetical etiological factor is the weakness of the vertebral endplate, possibly due to predisposing genetic background that influences the quality of matrix components (collagen types II and IX)8,12. Other authors describe abnormalities of cartilage, collagen fibrils and irregularity of mineralization and ossification of the vertebral endplates13,14. These observations suggest that genetic and/or metabolic predisposition together with mechanical stress of the anterior part of vertebral bodies may cause vertebral body deformation15,16. The diagnosis of SD is established and based on clinical and radiological presentation of the disease11. Most authors use the diagnostic criteria introduced by Sorensen 17 however, there exist other diagnostic classifications, differing by the number of affected vertebrae and additional findings, such as irregularities of the vertebral endplates, Schmorl nodes, narrowing of the disc spaces, and lengthening of the vertebral bodies in the sagittal plane11. Non-structural thoracic hyperkyphosis is more common in adolescents than the structural hyperkyphosis. It is often described as a postural hyperkyphosis (PHK) or „round back”. The reported prevalence of PHK differs around the world. It is found in 7.5%-30% depending on the measures criteria and age of children1,18,19. The pathology usually consists of combination of an incorrect postural habit and muscles’ hypo- or hyperactivity3. Radiographs reveal normal vertebral structure, however the thoracic kyphosis angle is increased20. At early stage the PHK can be corrected voluntarily by the patient and disappears spontaneously in the supine position. It may become stiffer with time1,20,21. PHK may be found in combination with increased lumbar lordosis. The clinical presentation of children with non-structural versus structural hyperkyphosis may be similar3. the tight hamstring muscles (semitendinous, semimembranous, and femoral biceps muscles) were reported in SD with the prevalence of 30% to 85%20,22,24. Fisk et al. suggested possible causative role of this finding in SD. According to Czaprowski et al. the hamstring muscles are not involved in PHK patomechanism or should be even lengthened in the PHK combined with increased lumbar lordosis3. AIM MATERIAL AND METHODS OBSERVATIONS AND RESULTS Forty patients were included to the SD group. There were 29 boys and 11 girls in the mean age of 13.9±1.8 years. Thirty patients were included to the PHK group. There were 9 boys and 21 girls in the mean age of 13.0±2.1 years, Table 1. There was not statistical significant difference for the sagittal spine alignment parameters, Table 1.
Table 1: Anthropometric description and the spinal sagittal parameters of the patients with Scheuermann`s disease vs. the patients with postural hyperkyphosis.
1Mann-Whithey test, 2 Chi2 test, 3 t-test Evaluation of the joint hypermobility revealed 2 cases of GJH in the PHK patients and 0 in SD patients. The difference was not significant, Table 1. The SD patients revealed significantly tighter hamstring muscles in PA test. The mean PA was bigger of 5.2° in SD patients, 0.0262, Table 2. The FTF distance was 6.3cm bigger in SD patients than in PK patients, p=0.0189, Table 2. There was no difference in Thomas test between the groups, Table 2.
Table 2: Evaluation of the muscles tightness in patients with Scheuermann`s disease vs. patients with postural kyphosis.
1Mann-Whithey test, 2t-test The shortening of the pectoralis major muscle was found in 60% of SD patients vs. 53.3% PHK patients, 0.6253. The shortening of the gastrocnemius muscle was found in 65% of SD patients vs. 53.3% PHK patients, 0.2814. The significance of hamstring muscles tightness between the groups depends on the cut-off point value. The difference is insignificant between the groups for the cut-off point of 30° and 60°. However, it is significant for the cut-off point of 40° with p=0.0453 and 50° with p=0.0062, Table 3.
Table 3: Percentage of patients with the tightness of the hamstring muscles depending on cut-off point.
1Chi Square test DISCUSSION The hamstring muscles tightness is an important issue in SD treatment. It has negative effect on the conservative treatment as well as on the surgical treatment results. In both cases stretching therapy is needed to improve the treatment results23,32,33. The occurrence of this phenomenon is observed in SD; however, the reason of coexistence of the structural kyphosis and the hamstring muscles tightness remains unclear. This phenomenon was noticed in the in the thirties of the twentieth century and described by Lambrinudi34. Fisk et al. was the first who suggested that thigh hamstring muscles might be important factor in SD etiology. They performed a pilot study on 20 patients and the incidence of the hamstring muscles contractures was 85%24. In the other study, they revealed that 56% of males and 30% of females with the tight hamstring muscles presented signs of SD35. Murray et al. found the hamstring muscles tightness in 29% of examined patients witch SD. What is more, they found correlation of back pain with the hamstring muscles tightness22. Hoseman et al. described occurrence of the hamstring muscles tightness in 48.5% of SD patients. They associated the tight hamstring muscles with higher risk of the post-surgical imbalance in SD23. They proved, that the tightness of the hamstring muscles is not just an accompanying phenomenon, but it also may have important impact on the patients’ health and the treatment results. Avanzi et al. evaluated group of 20 SD and 18 PHK patients. They found the hamstring muscles tightness in 85% of SD patients and in 83.3% of PHK patients20. All mentioned studies describe occurrence of the hamstring muscles tightness in SD patients based on the occurrence of the PA values above the cut-off point measured with a classical goniometer20,22,24. In this study we performed more comprehensive evaluation of the generalized muscles tightness and GJH. We do not only focus on the occurrence of the muscles tightness, but also we stratified it using angles measures. We have added FTF test which evaluate the hamstring muscle together with the spine and the gastrocnemius muscle flexibility 29,36 In the evaluation of the mean values of PA and FTF we have found significantly tighter the hamstring muscles in SD than in PHK patients in each test. An interesting result revealed analysis of the occurrence of the hamstring muscles tightness. A high percentage of the muscle tightness in both groups was found when the most commonly used cut-off value of 30°20,22,24. It was much higher then described by Murray et al. or Hoseman et al. and close to results described by Fisk et al. or Avanzi et al.20,22,24. The difference was not significant between the groups for this cut-off value. Similar results were described by Avanzi et al., the high occurrence rate of the hamstring muscles in both groups without significant difference in the occurrence distribution20. However, when we decreased the cut-off point the significant difference in the distribution was noted. We have evaluated other muscles potentially involved in the postural control except the hamstring muscles. We did not found significant differences between the groups of the other evaluated muscles tightness. What is interesting, the occurrence of the gastrocnemius muscle and pectoralis major contractures were high in the both groups. The study revealed, that in the SD group there was no patient with GJH, when in the PHK group there were 2 cases (6.6%). The reports of the GJH differ significantly among publications from 7% to 36%, depending on gender, ethnicity, age and cut-off point37. The prevalence of GJH in the similar age group in this region is reported at the level of 9.5% of the population for a cut-off 5 points or more of the Beighton score38. In this study PHK patients revealed 2.9% lower prevalence of the GHJ, than is presented in the published data for the evaluated region for children in similar age38. The patients form the evaluated groups were in comparable age. It was important due to fact that muscles flexibility changes with age20,37. The weight was also similar, however, the patients from the SD group were taller, than the patients from the PHK group. The most important difference was noted in a gender distribution between the evaluated groups. In the SD group there was 2.6:1 in favor of males, whereas, the gender ratio was 1:2.3 in favor of females in the PK group. Murray et al. and Fisk et al. reported the similar ratio for the genders (around 2:1) in SD22,24. The groups did not differ significantly in the spinal sagittal parameters. Although, we have expected some differences, such a similarity makes the comparison more significant. It was not planed to select the patients according to in the spinal sagittal parameters at the study design stage. It confirms the opinion that the clinical presentation of children with non-structural versus structural disturbances of body posture may be similar3. The strong side of this study is that it is comprehensive analysis of the muscles tightness in SD. It gives additional information of the other muscles than the hamstring muscles, that were not evaluated yet. To our knowledge, this is the first study evaluating GJH in SD patients. The limitation of this study is the retrospective design. However, based on this study prospective study may be designed. What is more, the comparison with the healthy peers group would be interesting.
CONCLUSIONS Patients with Scheuermann`s disease reveal more significant tightness of the hamstring muscles than patients with postural hyperkyphosis. High occurrence of the gastrocnemius muscle tightness was noted. The generalized joints hypermobility is not common in patients with Scheuerman`s disease.
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