developmental hip dysplasia ( ddh ) presents considerable technical challenges to the primary arthroplasty surgeon .
harris first described the technique of bulk autogenous grafting to achieve superolateral bone coverage in 1977 , and while early - to - midterm results were promising , longer term outcomes have been mixed . in harris 's series ,
21% of patients had radiographic evidence of loosening at seven years , and outcomes at mean sixteen years showed a high rate of acetabular failure due to component loosening and graft collapse . recently , however , more favourable long - term outcomes have been reported in ddh patients utilizing bulk autografts with both cemented [ 46 ] and uncemented   implants . achieving union and stability of the autogenous graft
bulk autogenous grafts are known to incorporate slowly and often incompletely ,   limiting their ability to respond to stresses under cyclic loading .
the main factors affecting incorporation of the graft are stability of the construct and host - graft bone contact [ 1 , 8 ] .
we describe a novel technique combining the use of bulk autograft with an iliac osteotomy which provides primary stability and optimises direct cancellous - cancellous bone contact and report mid - term results on 21 patients .
during the period 19982001 , 21 hips in 21 patients were managed with autologous bone graft in combination with an iliac osteotomy at our institution .
there were 3 men and 18 women in the study group , and the average age at the time of surgery was 50.1 years ( range 2677 ) .
the diagnosis in all patients was ddh , with a defective acetabular roof which would lead to uncovering of the acetabular component when placed in the desired position without augmentation .
preoperative radiographic planning with use of transparent overlays and socket templates is first performed to evaluate the position of the socket and autograft and potential coverage .
a posterior approach was used , with the short external rotators divided at their insertion and reflected to protect the sciatic nerve .
a full capsulectomy was performed , and a pin inserted above the acetabulum and the distance to a fixed point on the greater trochanter measured to give an estimate of leg lengthening once trial components were placed .
the acetabulum was sequentially reamed with the aim of positioning the socket at the level of the true acetabulum . at the base of the deficient superolateral portion of the true acetabulum
, a three - sided chamfered osteotomy is performed in the ileum and a wedge of bone is removed .
the resected femoral head is then used as a graft with the base of the neck cut into a wedge matching the chamfer on the iliac osteotomy ( figures 1 and 2 ) .
a tight fit is achieved by fine adjustments to the graft with a saw , and this is used as a stem to place the graft into the site of the iliac osteotomy .
the graft is impacted into place before being finally secured with partially threaded screws with or without washers .
this construct then is reamed in the usual way , and reamings are packed into any minor defects that remain .
after a saline wash , all the polyethylene cup ( lubinus , waldemar link , hamburg , germany ) was then cemented in the desired position , aiming to achieve an inclination angle of 45 and 1030 degrees of anteversion . the femoral canal was then broached and sequentially reamed before a collared monoblock implant ( lubinus sp - ii , waldemar link , hamburg , germany ) was cemented in situ .
radiographs taken preoperatively and postoperatively at 1 , 3 , 5 , 7 , and 9 years were assessed by two observers ( swy and fc ) .
postoperatively , the inclination angle of the socket was measured in relation to kohler 's line , and the amount of coverage of the socket was expressed as a percentage of the horizontal distance between the most medial point and the most lateral edge of the socket [ 3 , 6 ] .
graft union was assessed by observing disappearance of the graft - host bone interface and the appearance of bridging trabeculae .
the horizontal ( distance from the inferior point of the teardrop ) and vertical ( distance from the interteardrop line ) locations of the cup were measured as described by russotti et al . .
resorption of the graft was assessed at each follow - up interval , and the cup - bone interface was assessed based on the zones of delee and charnley . loosening the cup was assessed based on the criteria of mulroy and harris , with vertical or horizontal migration > 2  mm or cement fracture , inclination change > 4 degrees , or a continuous radiolucent line > 1  mm or noncontinuous radiolucency > 2  mm at the acetabular cement - bone interface considered evidence of loosening .
the preoperative radiographic classification was crowe type i in 12 hips ( 57% ) , type ii in 4 hips , and type iii in 5 hips , and the mean sharp angle was 49.6 ( range 4260 ) .
immediate postoperative radiographs showed a mean acetabular inclination angle of 43 ( range 2862 ) , and the average coverage of the component by graft was 40.2% ( range 2460% ) .
the mean horizontal location of the hip centre was 35  mm ( range 2242  mm ) lateral to the teardrop .
the mean height of the hip centre was 31  mm ( range 2056  mm ) vertically from the interteardrop line .
russotti and harris   defined proximal placement of the socket as 35  mm of vertical displacement , and according to these criteria six patients had proximal placement of the socket .  
, all hips were functioning well with no clinical signs of loosening and no revisions had been performed ( figures 3 and 4 ) . there was no discernible graft resorption or collapse and no patient had acetabular loosening according to our criteria .
no patient had vertical or horizontal migration > 2  mm or a change in the inclination angle > 3. two patients had noncontinuous radiolucent lines of < 1  mm visible at seven - year followup which were not apparent at 3 or five year followup .  
postoperative complications included transient neuropraxias in 3 patients , an episode of dislocation in one patient which was treated with closed reduction .
two patients showed evidence of heterotopic ossification , one brooker stage i and one brooker stage ii . there were no infective complications .
a combination of a high local incidence of ddh in bolivia , possibly related to both genetic and environmental factors including swaddling of infants , together with limited primary care facilities in childhood leads to a high proportion of patients presenting in the 3rd or 4th decade of life with degenerative hip disease .
developmental dysplasia of the hip presents considerable difficulties in restoration of the acetabular anatomy and achieving coverage of the acetabular component , particularly in the superolateral region .
strategies to address this problem include proximal positioning of a smaller cup [ 13 , 16 ] penetration of the medial wall ( protrusio technique ) [ 17 , 18 ] , an iliac sliding graft , and lateral bulk grafting [ 1 , 46 ] with either autogenous or allogenic bone .
while all of these techniques have reported satisfactory medium term results , bulk autogenous grafting has been favoured by many authors as it allows more anatomic cup placement and provides early structural support to the acetabular component , and there is a ready availability of autogenous graft in the form of the resected femoral head .
a further advantage is the augmentation of pelvic bone stock in case of subsequent revision , an important consideration given the often early age of onset of secondary degenerative change in this population group
.   published results of bulk autograft in ddh have been variable , probably because of differences in patient selection , the severity of dysplasia , bone quality , and the technique of bone grafting and components used .
reported good early results in 27 hips in 22 patients   but subsequently reported a combined clinical and radiographic rate of 60% at 16 years with failures due to graft resorption and collapse .
in contrast , kobayashi et al .   reported on 37 hips at a mean of 19 years after cemented arthroplasty with 100% survival of the socket , and other authors have also reported favourable outcomes [ 4 , 5 , 7 , 2022 ] .
previous studies have identified the two most important factors in graft incorporation as the host - graft bone contact and the stability of the graft [ 1 , 8 , 9 , 19 ] .
harris originally described  scoring  of the lateral cortex of the ileum before directly bolting the curvature of the femoral head against the ileum . later
authors have described using a cut surface of the femoral head [ 7 , 22 ] as a graft to ensure cancellous bone is contact with the ileum .
in addition , kobayashi described preparation of the ileum with multiple drill holes   to obtain a bleeding bone bed to encourage graft incorporation .   in this study
, we describe a technique of graft and iliac preparation which maximises the area of cancellous - cancellous bone contact between graft and host bone .
in addition , the bevelled nature of the osteotomy allows impaction of the graft and gives primary stability , meaning that the screws provide supplementary fixation only .
this optimises the biological situation for revascularisation and incorporation of the graft , which hopefully will lead to an increase in bone stock and possibly reduced resorption and failure rates in the longer term .  
ikeuchi et al .   described the use of a sliding iliac graft for acetabular reconstruction in ddh patients which utilised a similar osteotomy to that in this study .
they reported excellent short term outcomes in 19 patients and noted rapid incorporation of the graft secondary to intimate host - graft contact and stability and a subsequent low rate of resorption .
however , the maximum thickness of the iliac graft was 14  mm , limiting the technique in more severe cases of dysplasia .
our method retains the advantages of host - graft contact and stability without limitation in available graft size .  
firstly , we used cemented implants only , due to availability and cost in the country where the study was performed . while early series on bulk autograft also used cemented implants , in recent years
secondly we lack pre- and postoperative clinical outcome scores , partly due to the lack of cultural and language appropriate validated scoring instruments .   in conclusion
, our study has shown that this technique variation combining an iliac osteotomy with bulk autograft in cases of developmental hip dysplasia provides early stability and reliable graft incorporation , together with satisfactory clinical and radiological outcomes in the medium term .
 developmental hip dysplasia ( ddh ) presents considerable technical challenges to the primary arthroplasty surgeon . 
 autogenous bulk grafting using the femoral head has been utilised to achieve anatomic cup placement and superolateral bone coverage in these patients , but reported outcomes on this technique have been mixed with the lack of graft integration and subsequent collapse , an early cause of failures . 
 we describe a novel technique combining the use of bulk autograft with an iliac osteotomy , which provides primary stability and direct cancellous - cancellous bone contact , optimising the environment for early osseointegration . 
 twenty - one hips in 21 patients with ddh underwent this technique and were followed for a mean of 8.1 years . 
 the preoperative radiographic classification was crowe type i in 12 hips ( 57% ) , type ii in 4 hips , and type iii in 5 hips , and the mean sharp angle was 49.6 ( range 4260 ) . 
 all grafts united by year . at time of followup , there was no radiographic evidence of graft collapse or loosening . 
 there were no reoperations . 
 our study has shown that this technique variation combining an iliac osteotomy with bulk autograft in cases of developmental hip dysplasia provides early stability and reliable graft incorporation , together with satisfactory clinical and radiological outcomes in the medium term . 
 longer term study is necessary to confirm the clinical success of this procedure . 