legg - calv - perthes disease ( lcpd ) is represented by osteonecrosis of the femoral head during childhood , which typically develops in children aged 3 to 10 years1,2,3,4 ) . the onset age of the patient , development of osteonecrosis and the pathogenesis of femoral head necrosis are the most important factors determining the success of initial treatment received during childhood . despite receiving treatment , some patients develop early - onset secondary osteoarthritis requiring total hip arthroplasty ( tha ) . a recent prospective series found a 5% rate of tha at 20 years after nonoperative treatment of lcpd5 ) . the outcomes of tha for patients with osteonecrosis of the femoral head are less satisfactory than those for patients with primary osteoarthritis6,7,8,9 ) . the technical difficulties of tha in patients who have lcpd are unique to the condition where the femoral head develops multi - planar deformities10 ) . the acetabulum is typically shallow , enlarged , and retroverted11 ) , and the head of the femur flattens and widens , becoming incongruent with the acetabulum . the greater trochanter becomes elongated , and the neck of the femoral head is short due to growth disturbance . secondary osteoarthritis of the hip occurs early in most patients , especially in those classified as stulberg types iii - v3 ) . as the normal proximal femoral anatomy is altered , femoral component implantation becomes more challenging12 ) . to our knowledge , a few articles have reported the outcomes of tha in patients with the sequelae of lcpd . the aim of this study was to review the results of tha in patients with lcpd with at least follow - up of two years . we retrospectively reviewed 23 patients ( 23 hips ) who underwent primary tha performed between march 2007 and may 2012 . all data for this study were retrieved from our institution 's database ; we did not see or contact patients specifically for this study ( kc14risi0749 ) . there were 11 men and 12 women with a mean age of 49.2 years ( range , 25 - 69 years ) at the time of the arthroplasty . the mean body weight was 67.1 kg ( range , 49 - 91 kg ) , and the mean body mass index was 27.3 ( range , 22.1 - 37.5 ) . the minimum follow - up was 2 year ( mean , 40.8 months ; range , 24 - 84 months ) . all prostheses were used bencox hip system ( corentec , cheonan , korea ) except one ( stryker , kalamazoo , mi , usa ) , and all had a neck taper of 12/14 mm and a 32 or 36 mm ceramic head ( table 1 ) . clinical results were evaluated on the 3 , 6 and 12 months postoperatively , and every following postoperative year . hips with a score of 90 points were defined as excellent , 80 - 89 as good , 70 - 79 as fair , and < 70 as poor14 ) . the relationship of thigh pain with radiolucent lines observed on radiographs , cortical hypertrophy , and pedestal formation was investigated . for radiological assessment , subsidence of femoral components , stress shielding , cortical hypertrophy , periprosthetic reactive lines , and osteolysis were examined by dividing the proximal femur into gruen zones15 ) on anteroposterior and lateral radiographs around the femoral components . femoral component fixation was graded as bony stable , fibrous stable , or unstable according to the criteria described by engh et al.16 ) . for the femoral component , subsidence of > 5 mm was classified as loosening according to the method of callaghan et al.17 ) . cortical hypertrophy was defined as an increase in the diameter of the cortex measured at the point of maximum hypertrophy . movement of the acetabular cup was compared using radiographs taken in the immediate postoperative period and at the final follow - up based on the anterior and posterior views of the hip . according to the method of dorr et al.18 ) , the distances between the acetabular component and kohler 's line and the teardrop were measured . the acetabular cup was defined as loosening if there was movement in the position of the cup of more than 2 mm vertically , medially , or laterally , if the radiolucent lines were widened more than 2 mm in the anterior , posterior , or lateral radiographs of the acetabular cup , or if the inclination angle changed by more than 5 degrees . we assessed the pre - operative and post - operative leg length discrepancy ( lld ) 6 months postoperatively using the method described by ranawat et al.20 ) on an anteroposterior radiograph of the pelvis , we drew a horizontal reference line through the inferior aspect of the teardrops ( the perpendicular distance between the reference line and lesser trochanter ) . we identified the presence of complications including sciatic nerve palsy , infection , dislocation , fractures in the ceramic head and liner , heterotopic ossification , and squeaking . the average harris hip score was improved from 48.3 points ( range , 42 - 67 ) preoperatively to 92.4 points ( range , 79 - 97 ) postoperatively . there were 15 excellent cases ( 65.2% ) , 7 good cases ( 30.4% ) , 1 fair case ( 4.3% ) , and no poor cases . no patients complained of thigh pain . in the final follow - up , all hips showed stable fixation . of these , no hip had no osteolysis , loosening subsidence around the implants ( fig . 1 ) . the average lld was improved -1.5 cm ( range , -2.5 - -0.7 cm ) preoperatively to 0.3 cm ( range , -0.1 - 0.7 cm ) postoperatively , and the average limb lengthening after operation was 1.8 cm ( range , 0.9 - 2.5 cm ) . the mean operation time was 94 min ( range , 55 - 130 min ) , and total amount of drainage was 443.3 ml ( range , 265 - 720 ml ) . postoperative sciatic nerve palsy in one hip ( 4.3% ) with postoperative sciatic nerve palsy was occurred due to over - lengthening , so we revised the tha with medicalization of acetabular cup and exchange with smaller sized stem ( fig . 2 ) . after revisional surgery , sciatic nerve palsy was improved to grade iv at the last follow - up . intra - operative fracture in three hips ( 13.0% ) was occurred during stem insertion , so these fractures were fixed with wires and cables , and weight bearing was not permitted until 6 weeks . this study evaluates a population of 23 patients treated in childhood for lcpd who later underwent tha . the goal of childhood lcpd treatment is to prevent end - stage arthritis , which today typically is addressed with tha . the present report focuses on a group of patients with lcpd who went on to tha as a result of their pediatric hip diagnosis . we found that although survivorship of these hip reconstructions was generally good , serious complications were frequent . in our series , the only previous report of tha survivorship in patients with a history of lcpd cites a 96% survivorship at 15 years for primarily ingrowth components21 ) . takenaga et al.22 ) report 86% 10- to 15-year survivorship for cementless implants in patients younger than age 50 years . thus , our series compares favorably with other reports of tha in a younger cohort of patients . however , we found a high rate of neurologic injury in patients with a history of lcpd undergoing tha . this is much higher than the reported risk of 0.17% of patients undergoing arthroplasty for any cause23 ) . although hip dysplasia has long been known to be a risk factor for neurologic complications , lcpd has not typically been thought of as a risk factor for sciatic nerve palsy . one small case series also reports a high rate of neurologic deficit in patients with lcpd undergoing arthroplasty ( 6%)22 ) . in our case , 2a ) , and the affected limb was post - operatively over - lengthened about 7 mm ( fig . the patients complained severe neurogenic pain on the affected leg , and motor weakness ( grade 0 ) . perhaps the longstanding nature of the shortened limb may put the patient at increased risk of neurologic injury compared with the typical patient with osteoarthritis . the surgeon should consider to over - lengthen the limb for patients with lcpd with severe length leg discrepancy . a high risk of intra - operative femoral fracture ( 13% in our series ) was observed compared with 3% of patients undergoing arthroplasty for any cause23 ) . . a press - fit femoral component could be difficult to achieve with modular implants where there is severe dysplasia in the proximal femur . the custom - made femoral design optimizes metaphyseal bone contact in the proximal femur , an important requirement in cementless thas24 ) . the bespoke stem design also allows correction of marked femoral neck anteversion , a common feature in patients with lcpd25 ) , and accommodation of the proximal femoral deformities created by previous surgery , ensuring a metaphyseal press - fit . careful preoperative evaluation , including the use of computed - tomography based systems26 ) , can reduce the overall intraoperative risks . thus , we can not attempt to correlate pediatric treatment of the disease or disease severity with our reported results of tha , because these data were deficient . the second , this study is a retrospective one performed in a small cohort observed patient with short - term follow - up . the third , it does not have control group of primary tha due to primary osteoarthritis . careful preoperative planning should be performed to overcome the technical pitfalls . if overcoming this early complication , the clinical and radiological evaluations showed excellent outcomes at average 40-month follow - ups .
purposepatients who have secondary hip osteoarthritis as sequelae of legg - calv - perthes disease ( lcpd ) are severe deformities of femoral head and acetabulum . 
 a few studies have presented that the clinical results and risks associated with total hip arthroplasty ( tha ) for patients with a history of lcpd were not satisfactory . in this study , we reported the radiographic and clinical outcomes of tha in patients with sequelae of lcpd.materials and methodsbetween march 2007 and may 2012 , 23 hips ( 23 patients ) underwent cementless tha and were followed up at least 2 years after surgery . 
 there were 11 male patients and 12 female patients with an average age of 49.2 years old ( range , 25 to 69 years old ) , and the average follow up period was 40.8 months ( range , 24 to 84 months ) . 
 the clinical and radiological evaluations were performed.resultsthe harris hip score improved from 48.3 points preoperatively to 92.4 points at the time of the last follow - up . the shortening of affected limb was improved from -1.6 cm to 0.2 cm . 
 the complications included one case of sciatic nerve palsy that developed after extensive lengthening of lower extremity , three cases of intraoperative femur fractures . 
 there was no component loosening.conclusionfractures and motor nerve palsies may be more frequent in this population . 
 careful preoperative planning should be performed to overcome the technical pitfalls . if overcoming this early complication , the clinical and radiological evaluations showed excellent outcomes at average 40-month follow - ups .