| BackgroundOsteonecrosis of the femoral head(ONFH)is a severe disabling disease that commonly affects patients in the second to fifth decades of life.In the United States,it is estimated that 10,000 to 20,000 new patients are diagnosed with ONFH annually,and 5% to 12% of total hip arthroplasties(THA)are performed based on this diagnosis.But higher revision rates and poor outcomes were observed in THA due to postoperation infection,thrombosis,prosthetic loosening and other complications.Thus,a large volume of medical literature exists reporting preservation surgery of the femoral head and delay of THA surgery for ONFH.One of the most common surgery for ONFH is pedicled iliac bone grafting,but intraoperative location and debridement of necrosis area are largely depends on the personal experience of surgeon and has risks of unprecise location,incompletely or excessively debridement as well as cartilage surface destruction.Based on these drawbacks,we demonstrate an novel technology for the treatment of ONFH with pedicled iliac bone graft assisted by individual digital design and three dimensional(3D)printed navigation templates.Many studies have shown that the size of necrosis area can affect the prognosis directly,but still few solution supporting the determination and 3D visualization observation of its size and location.To solve these problems,we here provide a digital technology to help surgeon by 3D digital reconstruction.Objective1.To investigate the feasibility and early effectiveness to treat osteonecrosis of the femoral head(ONFH)with pedicled iliac bone graft assisted by individual digital design and three dimensional(3D)printed navigation templates.2.To investigate the feasibility of accurate measurement of necrosis area and the femoral head by 3D digital reconstruction.Methods1.From February 2014 to March 2015,39 patients(52 hips)with ONFH underwent pedicled iliac bone graft assisted by individual digital design and 3D printed navigation templates.There were 32 males(42 hips)and 7 females(10 hips)with a mean age of 34.7 years(range,18-56 years)and a mean disease duration of 10.6 months(range,1-36 months);the left hip was involved in 11 cases,the right hip in 15 cases,and both hips in 13 cases.There were 9 cases(16 hips)of steroid-induced ONFH(26%),16 cases(19 hips)of alcohol-induced ONFH(41%),4 case(4 hip)of traumatic ONFH(10%),and 10 cases(13 hips)of idiopathic ONFH(23%).The preoperative Harris score was 60.04±6.89.According to Association Research Circulation Osseous(ARCO)staging system,22 hips were classified as stage IIB,10 hips as stage IIC,10 hips as stage IIIB,and 10 hips as stage IIIC.The navigation templates were designed and printed to assist accurate location and debridement of necrosis area according to preoperative CT scanning at the beginning of pedicled iliac bone grafting procedure.2.21 hips with ONFH were included(10 underwent THA)from March 2015 to March 2016 for CT scanning,data were analyzed by Mimics 15.0,and the 3D digital model of femoral head and necrosis area were reconstructed,the size and ratio of necrosis area to femoral head were calculated and compared to actual data.ResultsThe mean operation time was 134.6 minutes(range,120-160 minutes),mean amount of bleeding was 266.2m L(range,200-300 m L).All the wounds healed primarily,no complication of deep vein thrombosis or infection was observed.All patients were followed up 13-25 months(mean,19 months).Postoperative X-ray and CT scanning shown the location of necrosis area was in accordance with preoperative design,which was removed completely without penetration of joint surface,pedicled iliac bone graft was performed at the right site according to postoperative imaging examination.Radiographically,graft fusion was achieved at 2.6 months(range,2-3 months)in all patients.2 hips collapsed during follow-up.Hip pain was relieved,and range of motion was improved.The Harris score was significantly improved to 89.62±5.31 at last follow-up(t=26.37,P=0.000).The results were excellent in 30 hips,good in 19 hips,fair in 2 hips and poor in 1 hip according to Harris score standard.2.The digital volume of femoral head and necrosis area were 45.53±5.34mm3 and 16.88±7.28mm3 respectively(N=21).The ratio of necrosis area to femoral head was 18.50±5.50%,and the actual volume of femoral head and necrosis area were 47.93±5.40mm3 and 21.74±4.55mm3 respevtively,the ratio of necrosis area to femoral head was 45.70±9.40%,no significant difference was found(t=1.09,P=0.31).Conclusion1.Pedicled iliac bone graft assisted by individual digital design and 3D printed navigation templates for treatment of adult ONFH has the advantages of accurate location and complete debridement of necrosis area,so satisfactory results can be obtained.2.3D digital reconstruction can be used for the measurement of volume of necrosis area,and benefit the surgeon on the location and debridement of necrosis area,as well as the estimate of amount for bone implanting. |
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