it is well known that patients with secondary hyperparathyroidism caused by chronic kidney 
 disease ( ckd ) develop secondary osteoporosis , which increases fracture risk .
we report here a case of 
 acetabular insufficiency fracture treated with total hip arthroplasty ( tha ) .
a 78-year - old man visited our hospital because he was unable to walk due to pain around the 
 left hip joint after falling in november 2010 .
he had a medical history of nephrotic 
 syndrome ( membranous nephropathy ) in 1995 and gastrectomy ( gastric cancer ) in 2005 . at the 
 initial hospital presentation , he was very thin ; his height was 152.5 cm , weight was 42.7 
 kg , and body mass index was 18.4 .
he complained of severe tenderness and pain on motion 
 about the left hip joint .
plain radiographs revealed no fracture in the left hip joint or the pelvis , although severe 
 osteoporosis with a singh index grade of 2 was observed in the femoral neck ( figure 1figure 1plain radiograph from the initial examination .
we performed magnetic resonance imaging ( mri ) to find any abnormality of the hip 
 joint .
t1- and t2-weighted images showed a line of low signal intensity running obliquely in 
 the metaphysis of the left femur , which represented an occult intertrochanteric fracture 
 ( figure 2figure 2magnetic resonance imaging ( coronal slice of the hip joint ; left , t1-weighted images ; 
 right , t2-weighted image ) .
a fracture line was observed running obliquely in the 
 metaphysis of the left femur . ) .
blood tests and a urinalysis revealed anemia , undernutrition , and renal dysfunction 
 ( table 1table 1initial examination of blood and urinewbc ( /l)5200rbc ( 100 million/l)2.76hb ( g / dl)8.3ht ( % ) 8.3plt ( 10000/l)13.4tp ( g / dl)5.6alb ( g / dl)2.4albumin / globulin0.8un ( mg / dl)40cre ( mg / dl)6.9k ( meq / l)4.8ca ( meq / l)6.5corrected ca ( meq / l)8.1alp ( iu / l)505ldh ( iu / l)135urine protein2 + ) .
written informed consent was obtained from the family of the patient for 
 publication of this case report and accompanying images .
magnetic resonance imaging ( coronal slice of the hip joint ; left , t1-weighted images ; 
 right , t2-weighted image ) .
a fracture line was observed running obliquely in the 
 metaphysis of the left femur .
he was hospitalized for conservative treatment of an occult intertrochanteric fracture of 
 the left femur . on the 10th day of hospitalization , he developed loss of appetite , nausea , 
 and vomiting .
a second set of blood tests and blood gas tests suggested acute uremic 
 symptoms due to deterioration of renal function and metabolic acidosis ( tables 2 and 
 3table 2second examination of blood and urineun ( mg / dl)75cre ( mg / dl)7.2k ( meq / l)5.8table 3arterial blood gas test on room airph ( mmhg)7.202pco2 ( mmhg)27.1po2 ( mmhg)116.8hco3 ( mmol)10.4base excess16.2 ) . he was immediately treated with hemodialysis . partial weight bearing on his left leg with a walker
eight weeks after the fracture , he suddenly 
 felt severe pain in the contralateral hip when he stood at his bedside .
because of severe 
 right hip pain , he was unable to stand or walk .
a plain radiograph showed an acetabular 
 fracture with penetration of the femoral head into the pelvis ( figure 3figure 3plain radiograph taken at the onset of pain in the right hip joint .
an acetabular 
 fracture and penetration of the femoral head toward the midline were observed , and 
 central fracture and dislocation of the right hip were diagnosed . ) .
we performed mri of the hip joint again and showed a right acetabular fracture and 
 signal changes suggesting hematoma of the right hip joint cavity ( figure 4figure 4magnetic resonance imaging of the hip joint after injury of the right hip ( coronal 
 slice of the hip joint ; left , t1-weighted image ; right , t2-weighted image ) .
an 
 acetabular fracture and signal changes suggesting hematoma around the fracture site 
 were seen in the right hip . ) .
computed tomography showed central dislocation due to penetration of the femoral 
 head through the inner table of the pelvis without fractures of the anterior and posterior 
 pelvic columns . on the basis of ct findings
, the patient was diagnosed with central fracture 
 dislocation of the right hip ( figure 5figure 5computed tomography of the hip joint after injury of the right hip ( left , multiplanar 
 reconstruction [ mpr ] coronal slice ; right , three - dimensional [ 3d ] reconstruction from 
 behind ) .
the 3d reconstruction shows that 
 the femoral head penetrated through to the inner region of the pelvis . ) .
blood and urinary tests were repeated to identify the cause of the insufficiency 
 fracture .
the blood biochemistry revealed a marked elevation of intact parathyroid hormone 
 ( 681 pg / ml ) , a decrease of 1,25-dihydroxyvitamin d3 ( 4.9 pg / ml ) , an elevation of 
 osteocalcin ( radioimmunoassay ) ( 25 ng / ml ) , a decrease of ca ( 7.0 mg / dl ) , and a 
 normal level of inorganic phosphorus ( 4.7 mg / dl ) .
the creatinine - corrected urinary 
 n - terminal telopeptide of type 1 collagen level was very high at 403.7 nmol bone collagen 
 equivalents / mmol creatinine .
the osteo sono - assessment index ( osi ) of the right calcaneum 
 was determined using an ultrasound bone assessment device ( aos-100nw , hitachi - aloka medical , 
 ltd . ,
the osi was 1.827 (  10 ) , which was 63% of the young adult 
 mean .
plain radiograph taken at the onset of pain in the right hip joint . an acetabular 
 fracture and penetration of the femoral head toward the midline were observed , and 
 central fracture and dislocation of the right hip were diagnosed .
magnetic resonance imaging of the hip joint after injury of the right hip ( coronal 
 slice of the hip joint ; left , t1-weighted image ; right , t2-weighted image ) .
an 
 acetabular fracture and signal changes suggesting hematoma around the fracture site 
 were seen in the right hip . computed tomography of the hip joint after injury of the right hip ( left , multiplanar 
 reconstruction [ mpr ] coronal slice ; right , three - dimensional [ 3d ] reconstruction from 
 behind ) .
the 3d reconstruction shows that 
 the femoral head penetrated through to the inner region of the pelvis . because he was elderly and had many medical complications , we selected tha rather than open 
 reduction and internal fixation of the pelvis .
surgery was delayed approximately 6 weeks 
 after the acetabular fracture to allow stabilization of the soft tissues at the fracture 
 site .
the morselized bone was mixed with artificial bone and packed tightly 
 into the freshened acetabulum .
then , an acetabular ring ( lima corporate , udine , italy ) was 
 placed in the acetabulum for reconstruction , and a zca snap - in cup ( zimmer , warsaw , indiana , 
 usa ) was cemented into place . for the femur , a versys cemented stem ( zimmer , usa ) was 
 cemented in place ( figure 6figure 6plain radiograph of the hip joint after surgery . ) .
he was 
 discharged 10 weeks after surgery on foot using a japanese style walker .
he reported no pain 
 in the right hip joint as of 18 months postoperatively .
although he needed a wheelchair to 
 travel long distances , he was able to walk with a cane for a short distance indoors .
the pathobiology of abnormal bone metabolism in patients with ckd is shown in figure 7figure 7abnormal bone metabolism in patients with chronic kidney disease . 

1,25(oh)2d3,1,25-dihydroxyvitamin d3 ; ip , inorganic 
 phosphorous .. the patient in this report had already developed secondary hyperparathyroidism 
 caused by chronic renal failure at the time of the initial examination he also had 
 postgastrectomy undernutrition and malabsorption of vitamin d. the 4 weeks of bed rest after 
 the left occult hip fracture might have increased bone resorption , resulting in severe bone 
 fragility , which might have caused the right nontraumatic central fracture dislocation of 
 the hip .
classified stress fractures into fatigue fractures , which 
 occur when abnormal stress is applied to bone with normal elastic resistance , and 
 insufficiency fractures , which are produced by rhythmic and repeated application of 
 subthreshold external force to bone with poor elastic resistance .
there are various underlying diseases that can 
 cause insufficiency fracture , including geriatric osteoporosis , rheumatoid arthritis , oral 
 steroid therapy , hemodialysis , radiotherapy for malignant diseases , and ckd .
there have been many case reports of fractures of the pelvis due to bone 
 fragility . according to goto et al . ,
the next most 
 common site of insufficiency fracture associated with rheumatoid arthritis , after the spine , 
 is the pelvis .
however , the majority of the pelvic insufficiency fractures in their study 
 were pubic bone fractures , and they did not include any acetabular insufficiency 
 fractures .
other studies 
 have reported cases of minor pelvic fractures diagnosed by radiographs or mri alone that 
 were successfully managed with conservative treatment .
however , there have been only a few case reports of central 
 fracture and dislocation of the hip requiring surgical treatment .
berman et al . reported the use of conservative treatment for central 
 fracture and dislocation of the hip in patients with chronic renal failure .
they observed that the clinical 
 course was excellent when partial weight bearing was initiated after traction and no weight 
 bearing for 8 weeks but thought that tha would be necessary later due to leg shortening . in 
 addition , hirao et al .
performed symptomatic treatment in adults with down 
 syndrome with severe bone fragility who developed central fracture and dislocation of the 
 hip with the expectation that the hip would undergo ankylosis in the dislocated 
 position .
this course 
 was chosen because either long - term traction and bed rest or surgery was considered 
 unsuitable in light of the patients level of comprehension and tolerance of the treatment 
 options .
the authors found that the pain in the hip joint was decreased 7 months after the 
 fracture but found that the range of motion was limited and that the patients could not move 
 without a wheelchair .
the major surgical treatments for central hip fractures with dislocation are open reduction 
 and tha , and in all of the reports that we found , tha was performed because of the 
 difficulty of anatomical internal fixation of the acetabulum protruding into the pelvis and 
 the severe operative stress involved .
reported 
 excellent outcomes after tha performed after 2 months without weight bearing in a patient 
 with rheumatoid arthritis and a patient with chronic liver injury , respectively . in summary , we experienced a case of pelvic insufficiency fracture in a patient with 
 secondary osteoporosis due to chronic renal failure and undernutrition .
tha with 
 reconstruction of the acetabulum was an effective option in the patient with nontraumatic 
 central fracture dislocation of the hip .
we report here a case of nontraumatic central fracture and dislocation of the hip in a 
 patient with ckd .
patients with undernutrition due to chronic renal failure may develop 
 severe insufficiency fractures such as this one .
tha with acetabular reconstruction using a 
 support ring and morselized bone graft was effective for treating central fracture 
 dislocation of the hip in a patient with these complications .
 objective : patients with secondary hyperparathyroidism caused by chronic 
 kidney disease ( ckd ) develop secondary osteoporosis , which increases fracture risk . 
 we 
 report a case of insufficiency fractures complicated by secondary osteoporosis caused by 
 chronic renal failure and gastrectomy.patient : a 78-year - old man with a medical history of nephrotic syndrome and 
 gastric cancer experienced an occult intertrochanteric fracture of his left femur after 
 falling.results : ten days after the first fracture , the patient was treated with 
 hemodialysis for acute uremic symptoms . 
 eight weeks after this fracture , he sustained a 
 right insufficiency acetabular fracture and was treated with total hip arthroplasty 
 ( tha).conclusion : for patients with ckd , effective fracture prevention is 
 difficult . 
 tha with reconstruction of the acetabulum was an effective therapy in a patient 
 with nontraumatic central fracture dislocation of the hip . 
Introduction
Patient
Discussion
Conclusion