gmc , also named  injection contracture ,  is a clinical syndrome characterized by gait abnormality and limb dysfunction including restriction of adduction and internal rotation of the hip joint .
it was first found by valderrama at a scientific meeting of the british orthopedic association in london in 1969 .
its pathologic change typically presents with fibrosis and contracture of the gluteus and its fascia .
the knees can not be brought together and are separated in a frog - leg position . as younger patients with gmc continue to develop and grow , pathologic changes increase in prevalence and severity including leg length discrepancy , pelvic oblique , compensatory scoliosis , and , in severe cases , bilateral dislocation of the hip joints .
now , arthroscopic release , a minimally invasive surgery which was reported by zhang et al for the first time , has became the gold standard of treatment in gmc patients .
compared with developed countries , gmc is more widely reported in china . so far , numerous studies have suggested that gmc usually was associated with repeated intramuscular injection into the gluteal region during childhood .
however , it remains unclear that , the reasons why these children are weak and have no choice to accept repeated intramuscular injection .
the paper reveals that chd children are prone to catching cold , repeated respiratory tract infection , or pneumonia and have to take frequently intramuscular injection which use benzyl alcohol as a dissolvent for penicillin in some regions of china in the 1970s and 1980s , leading to degeneration , necrosis and fibrosis of the gluteal muscles and fascia , as well as serious limitation of hip movements .
we identified 4 gmc adolescents with chd from january 2013 to march 2014 . the duration of symptoms ranged from 6 to 10 years .
there were 2 males and 2 females with age ranging from 14 to 17 years ( table 1 ) .
although 3 of 4 patients ( patients 1 , 3 , and 4 ) had limitations with activities of daily living , they believed their activity levels were lower than those of healthy people .
three of 4 patients ( patients 1 , 3 , and 4 ) had an abnormal gait with out - toe walking , and could not crouch with both knees close to each other or sit down with their legs crossed .
patient 1 was diagnosed as chd for the first time , while the other 3 had been cured yet .
two representative patients ( patients 1 and 4 ) were selected for further discussion of their clinical and radiographic findings ( table 2 ) .
clinical characteristics of the patients radiographic findings of the patients each author certifies the study had approved , by ethics committee of peking university shenzhen hospital , for the reporting of these cases and that all investigations were conducted in conformity with ethical principles of research .
patient 1 was a 16-year - old girl who had bilateral diseases with gluteal muscle atrophies , abnormal gait with out - toe walking , dimpling of skin around the gluteal regions , snapping hips , adduction and internal rotation dysfunction of hips , ober 's signs .
the most thing affected her was adduction and internal rotation dysfunction of hips , which made her not to do competitive sports ( actually , it was mainly influenced by chd which was diagnosed later . ) like other healthy girls .
3d reconstruction ct showed that her gluteus maximus and gluteus medius were obviously dysplastic and part of them turned to contractile bands .
we heard a systolic ejection murmur at the second left intercostal space in preoperative examinations .
furthermore , chest x - ray revealed pulmonary vascularity , cardiac enlargement and aortic knob shrinking .
finally , cardiac ultrasound proved the diagnosis of asd . because of this , we sent her to cardiosurgery department for atrial septal defect closure and partial anomalous pulmonary venous drainage correction on beating heart .
the arthroscopic release and rehabilitation program for gmc were operated 110 days later , when she was completely rehabilitated from cardiosurgery .
three months later , the patient gained a satisfactory result without complications , snappings , and dysfunctions of hip ( figure 1 ) .
( a ) a 3d reconstruction ct shows the gluteal muscles of patient 1 , a 16-year - old woman who had gmc with severe gluteus maximus and gluteus medius atrophy .
( b ) and ( c ) show the contracture bands ( white arrow ) in left and right side , respectively .
( e ) chest x - ray reveals pulmonary ascularity , cardiac enlargement and aortic knob shrinking .
patient 4 was a 17-year - old boy who had bilateral diseases with gluteal muscle atrophies , abnormal gait with out - toe walking , dimpling of skin around the gluteal regions , snapping hips , adduction and internal rotation dysfunction of hips , ober 's signs .
the most things affected him was adduction and internal rotation dysfunction of hips , as well as snapping hips . due to a failed open surgery before
when he was very young , he was taken ligation of patent ductus arteriosis ( the detailed data of that surgery were unavailable ) .
3d reconstruction ct showed that his gluteus maximus and gluteus medius were obviously dysplastic and part of them turned to contractile bands .
three months later , the patient gained a satisfactory result without complications , snappings , and dysfunctions of hip ( figure 2 ) .
( a ) a 3d reconstruction ct shows the gluteal muscles of patient 4 , a 17-year - old man who had gmc with mild gluteus maximus and gluteus medius atrophy .
( b ) and ( c ) show the contracture bands ( white arrow ) in left and right side , respectively .
patient 1 was a 16-year - old girl who had bilateral diseases with gluteal muscle atrophies , abnormal gait with out - toe walking , dimpling of skin around the gluteal regions , snapping hips , adduction and internal rotation dysfunction of hips , ober 's signs .
the most thing affected her was adduction and internal rotation dysfunction of hips , which made her not to do competitive sports ( actually , it was mainly influenced by chd which was diagnosed later . ) like other healthy girls .
3d reconstruction ct showed that her gluteus maximus and gluteus medius were obviously dysplastic and part of them turned to contractile bands .
we heard a systolic ejection murmur at the second left intercostal space in preoperative examinations .
furthermore , chest x - ray revealed pulmonary vascularity , cardiac enlargement and aortic knob shrinking .
finally , cardiac ultrasound proved the diagnosis of asd . because of this , we sent her to cardiosurgery department for atrial septal defect closure and partial anomalous pulmonary venous drainage correction on beating heart .
the arthroscopic release and rehabilitation program for gmc were operated 110 days later , when she was completely rehabilitated from cardiosurgery .
three months later , the patient gained a satisfactory result without complications , snappings , and dysfunctions of hip ( figure 1 ) .
( a ) a 3d reconstruction ct shows the gluteal muscles of patient 1 , a 16-year - old woman who had gmc with severe gluteus maximus and gluteus medius atrophy .
( b ) and ( c ) show the contracture bands ( white arrow ) in left and right side , respectively .
( e ) chest x - ray reveals pulmonary ascularity , cardiac enlargement and aortic knob shrinking .
patient 4 was a 17-year - old boy who had bilateral diseases with gluteal muscle atrophies , abnormal gait with out - toe walking , dimpling of skin around the gluteal regions , snapping hips , adduction and internal rotation dysfunction of hips , ober 's signs .
the most things affected him was adduction and internal rotation dysfunction of hips , as well as snapping hips . due to a failed open surgery before
when he was very young , he was taken ligation of patent ductus arteriosis ( the detailed data of that surgery were unavailable ) .
3d reconstruction ct showed that his gluteus maximus and gluteus medius were obviously dysplastic and part of them turned to contractile bands .
three months later , the patient gained a satisfactory result without complications , snappings , and dysfunctions of hip ( figure 2 ) .
( a ) a 3d reconstruction ct shows the gluteal muscles of patient 4 , a 17-year - old man who had gmc with mild gluteus maximus and gluteus medius atrophy .
( b ) and ( c ) show the contracture bands ( white arrow ) in left and right side , respectively .
we present a series of 4 gmc patients with chd , including asd , vsd , tof , and pda respectively .
accordingly , we suggest that some gmcs are related to chds , or rather are derived from chds .
to be specific , children suffered from chds are easy to acquire respiratory infections ( nearly one - quarter to one - third ) , which may be result in frequent use of benzyl alcohol as a dissolvent for penicillin for intramuscular injections in some regions of china in 1970s1980s , as several researchers have suggested that benzyl alcohol is the main cause of gmc .
this series is limited by its small size relating to the decreasing of gmc for abandoning benzyl alcohol as a dissolvent .
patient 1 was admitted to hospital for releasing gmc , however , asd was found in preoperative examinations .
this warns that surgeons should attach more importance to the cardiac examination , especially identifying the real cause of  can not do competitive sports .
 when chd is repaired and physical condition is fully recovered , it is time to release gmc . at last
patient 4 was hospitalized in order to cure gmc through a minimally invasive surgery for a noneffective open surgery 4 years ago . with the normal results of physical examinations and chest x - ray , we did arthroscopic release directly , like other common gmc patients without chd .
result relationship between the 2 diseases , we propose 3 recommendations : ( 1 ) as to chd children , in addition to treating the primary disease as early as possible , it is essential to decreasing the use of intramuscular injection , and ( 2 ) paying more attention to cardiac examination especially cardiac ultrasound in perioperative period , and ( 3 ) taking 3d - ct to reconstruct gluteal muscles for observing contracture bands clearly in preoperation .
 abstractgluteal muscle contracture ( gmc ) , presented with hip abduction and external rotation when crouching , is common in several ethnicities , particularly in chinese . 
 it remains unclear that the reasons why these children are weak and have no choice to accept repeated intramuscular injection . 
 here , we found some unique cases which may be useful to explain this question.we describe a series of special gmc patients , who are accompanied with congenital heart disease ( chd ) . 
 these cases were first observed in preoperative examinations of a patient with atrial septal defect ( asd ) , which was proved by chest x - ray and cardiac ultrasound . from then on , we gradually identified additional 3 gmc patients with chd . 
 the original patient with asd was sent to cardiosurgery department to repair atrial septal first and received arthroscopic surgery later . while the other 3 were cured postoperative of ventricular septal defect ( vsd ) , tetralogy of fallot ( tof ) , patent ductus arteriosus ( pda ) , respectively , and had surgery directly.the study gives us 3 proposals : ( 1 ) as to chd children , it is essential to decrease the use of intramuscular injection , ( 2 ) paying more attention to cardiac examination especially cardiac ultrasound in perioperative period , and ( 3 ) taking 3d - ct to reconstruct gluteal muscles for observing contracture bands clearly in preoperation . 
 however , more larger series of patients are called for to confirm these findings . 
INTRODUCTION
PATIENTS AND METHODS
CASE REPORTS
Case 1
Case 2
DISCUSSION
CONCLUSIONS