Observation And Evaluation Of Surface Electromyography Of Children In The Final Classification Of LCPD And Its Correlation With The Force Area Of The Femoral Head

Objective:In this retrospective study,we measured the surface electromyography of the muscles around the hip joint in children with LCPD who finished clinical treatmen according to the modified Stulberg classification.We preliminarily explore the possible changes using the data we measured combining with the changes of the two-dimensional weight-bearing area of the femoral head.Method:The surface EMG data and last follow-up X-ray of LCPD patients diagnosed in the Pediatric Orthopedics Department of Hunan Provincial People’s Hospital from January 2014 to June 2020 were collected.A total of 41 people who reached the healing period of Waldenstr?m and resumed walking for 1 year were involved.We set up three groups: the affected side group,the healthy side control group(healthy side group),and the normal control group(normal control group).The s EMG-RMS signals was measured when standing and walking,then the results of each group were compared.Second,All patients were divided by Stulberg classification into three groups: excellent,moderate and poor.Tthe RMS signals of the s EMG during standing and walking in the three groups of excellent,moderate and poor for intra-group were compared.Third,the force area of the femoral head of the affected hip with a two-dimensional mathematical stress model in second part was calculated,the results from each group and result from the healthy control group and the normal control group were compared.Combined with the modified Stulberg classification,the relationship between the changes in s EMG-RMS and the force area of the femoral head in each group was analysised.Results:(1)Results when standing: The affected side hamstring muscle RMS value was weaker in the affected side group(7.9587),compared with the healthy side control group(12.8000)and the difference is statistically significant(P=0.03<0.05);the RMS value of tensor fascia lata in the affected group(4.2462)was higher than that of the normal control group(2.5908);the RMS value of the gluteus maximus in the affected group(2.3171)was weaker than that of the normal control group(4.1344),The differences were statistically significant(P=0<0.05);the hamstring muscle and tensor fascia lata RMS values in healthy side control group(12.8000 and 4.1956)are higher than the normal control Group(8.4657 and 2.5908),the differences were statistically significant(P=0.011<0.05 and P=0.002<0.05);the RMS value of gluteus maximus in the contralateral control group(3.0080)was lower than that of the normal control group(4.1344),the difference was statistically significant(P=0<0.05).(2)Results when walking: the hamstring muscle RMS value of the affected side group(28.7802)was weaker than that of the healthy side control group(43.1717),the difference was statistically significant(P=0<0.05);the tensor fascia lata RMS value(39.5429)of the ipsilateral group was higher than that of the normal control group(29.2647),the difference was statistically significant(P=0.022<0.05);the gluteus maximus of the ipsilateral group The RMS values of(10.6298),rectus femoris(20.2489)and hamstrings(28.7802)were all weaker than those of the normal control group(20.0361,27.4778 and 33.09,respectively),the differences were statistically significant(significantly P=0< 0.05,P=0<0.05 and P=0.007<0.05).The hamstring muscle RMS value of the healthy side control group(43.1717)was higher than that of the normal control group(33.0900),the difference was statistically significant(P=0.007<0.05).The RMS values of gluteus maximus and rectus femoris in the contralateral control group(14.3061 and 23.4951,respectively)were lower than those in the normal control group(20.0361,27.4778,respectively),and the difference was statistically significant(P=0<0.05).(3)The RMS value of each target muscle during standing and walking of the inner s EMG of the modified Stulberg classification in excellent,medium and poor groups shows there was no statistically significant difference.(4)Calculation results of the force area of the femoral head of the affected hip:According to the modified Stuburg classification,the force area of the femoral head of the superior,moderate,and poor groups showed a downward trend(the force area was0.7137,0.6417,and 0.4838,respectively).The force area of the excellent group was similar to that of the healthy side control group(forced area was 0.7137 and 0.6824respectively),There were no significant differences in this two groups.Compared with the normal control group(0.8010),the stress area of the excellent,moderate and poor groups and the healthy side control group were all reduced,the differences were statistically significant(significantly P=0.035<0.05,P=0<0.05,P= 0<0.05,P=0.001<0.05).The area of force in the poor group was smaller than that in the superior group and the middle group,the difference was statistically significant(significantly P=0<0.05,P=0.004<0.05).(5)In the modified Stulberg classification,there is no correlation between the changes in the force area of the femoral head and the groups and the s EMG-RMS values of the four target muscles.Conclusion:(1)In children with LCPD who finish treatment,the muscles around the hip joint on the affected side will have varying degrees changes of muscle strength;the muscles strength around the hip joint on the healthy side also have adaptive changes.But there is no evidence that these muscle strength changes will change with the modified Stulburg classification.(2)The force area of the affected femoral head of children with LCPD tends to decrease with the deterioration of the modified Stulburg classification.(3)With the deterioration of the modified Stulburg classification of the LCPD hip,there is no correlation between the changes in the force area of the femoral head and the changes of the s EMG-RMS value of the muscles around the affected hip.