| Osteonecrosis of the femoral head(ONFH)is a common disease in hip surgery and an refractory orthopaedic disease.Its onset is insidious,if not treated timely and correctly,the femoral head may collapse in a short time,seriously affecting the joint function,and the disability rate is extremely high.Preservation of the femoral head and delay,or even avoidance of total hip arthroplasty is a difficult and hot topic in clinical research.Although the clinical application of iliac bone flap transplantation with ascending branch of lateral circumflex femoral artery(LCFA)in the surgical treatment of ONFH has achieved curative effects,there remains a large damage to the surrounding tissue.Furthermore,accurate quantitative selection of the bone flap transplantation area and bone flap size is still an issue to be solved.In chronic cases,iliac bone flap transplantation for middle and late stage ONFH can’t provide the effective mechanical support and result to poor clinical outcomes.In view of this,this paper was designed to improved bone flap grafting method with less damage to surrounding tissues and enable adaptation to the biomechanical environment by using the musculoperiosteal iliac flap with the ascending branch of LCFA in ONFH treatment.Based on anatomical and finite element analysis,asystematic study of the structure-activity relationship of bone flap transplantation was carried out,and its effectiveness was verified from clinical perspective.The main contents can be summarized as:(1)Based on the anatomical study,the musculoperiosteal iliac flap with the ascending branch of LCFA was designed.A two-dimensional coordinate system was introduced to locate the musculoperiosteal iliac branch with the ascending branch of LCFA and to clarify its anatomical characteristics and blood supply range,providing a fundamental method for accurate bone flap selection.18 fresh cadaveric hip joint specimens were dissected.Taking the pubic symphysis as the origin,the straight line from the pubic symphysis to the anterior superior iliac spine represented the x-axis,and the line parallel to the sagittal plane of the body as represented the y-axis.The course,diameter and blood supply range of the musculoperiosteal iliac branch with the ascending branch of LCFA were measured.The result showed that origin of LCFA is(50.28 ± 4.40 mm,49.39 ± 8.53 mm),the coordinate of the intersection point of the musculoperiosteal iliac branch of the iliac crest branch is(84.47 ±7.80 mm,27.60 ± 5.93 mm).The distance from bifurcation of iliac crest branch to anterior superior iliac spine is 3.35 ± 0.69 cm,and the distance from the bifurcation of iliac crest branch to the junction of femoral head and neck is 2.38 ± 0.44 cm,and the average diameter of the musculoperiosteal iliac branch is 0.23 ± 0.06 mm.The blood supply range of the anterior superior iliac spine is about 3 cm×3 cm×2 cm.The research results show that the same incision can meet the requirements of bone flap transposition,the positioning of the blood vessels improves the accuracy of surgery,and the precise design of the musculoskeletal flap avoids damage to other blood supply sources that would have resulted in bone flap transplantation.(2)To solve the biomechanical adaptation,and the placement of grafted iliac bone flap with vascular pedicle in femoral head,finite element analysis method was used to transplant vascularized iliac bone flap into head necrosis area.The displacement and stress before and after operation were compared and quantitatively analyzed.The results before iliac bone flap transplantation showed that the peak stress of femoral head necrosis was 7 MPa higher than that of normal femoral head;after bone flap transplantation,the stress concentration in necrotic area of femoral head was significantly reduced,and the overall strain of femoral head decreased.Bone flap stress is minimal when positioned with in the femoral head at 20°anterior to the coronal plane.Therefore,iliac bone flap transplantation can significantly improve the stress concentration in the necrotic area and restore the internal mechanics conditioning of the femoral head.The best positioning of the iliac bone flap placement is at anterior femoral head,at the 20° coronal plane.The results of this study clarified the biomechanical adaptation position of the bone flap and provided guidance for the orthopedic surgeon to apply the bone flap effectively and accurately.(3)Based on anatomical experiments,finite element analysis,and 3D visual navigation technology,it is shown that for ONFH with necrosis less than 15 % and at the early and middle stages,the musculoperiosteal iliac bone flap with the ascending branch of LCFA can be accurately used for transplant treatment of ONFH.The Harris Hip Score(HHS),Visual Analogue Score(VAS),gait analysis,and radiographic appearance of both hips were used to analyze the changes in hip joint function before and after surgery.The clinical results showed that the Harris score of the patient’s hip joint increased from 52.33 ± 3.34 points before surgery to 79.75±3.84 points at 12 months after surgery,while the VAS score decreased from8.07±0.31 points before surgery to 2.27 ± 0.23 points at 12 months after surgery.Gait analysis showed that the patient’s stride length,stride speed and stride frequency were significantly improved after surgery(p<0.01).Hip imaging showed that the femoral head was in good shape,the femoral head did not collapse,and the grafted bone flap healed well.Compared with relevant literature reports using iliac bone flap transplantation for early and mid-stage ONFH,this group has obvious advantages in terms of operative blood loss and operative time.The musculoperiosteal iliac flap with the ascending branch of LCFA placed at the appropriate biomechanical angle can be used to accurately treat the early and middle stage ONFH,improving the function of the hip joint.(4)For the treatment of ONFH in the middle and late stages.i.e necrosis of the femoral head greater than 15 %,musculoperiosteal iliac bone flap with the ascending branch of LCFA was combined with porous tantalum screw for this treatment.The results showed that the Harris hip score of patients with hip preservation after surgery increased from 50.1 points to89.1 points in stage III and from 40.5 points to 84.1 points in stage IV.With a mean follow-up of 30 months,the hip survival rate was 86.7 % in stage III and 44.4 % in stage IV,which was higher than reported survival rate and hip function scores.Imaging evaluation showed that70.6 % of hip joints maintained stable without progression after operation,and at the end of this follow-up,the grafted iliac bone flap and femoral head healed well.In the case of large necrosis and insufficient supporting force of vascularized bone flap transplantation,biomechanical adaptation of porous tantalum screws can enhance the mechanical strength of the femoral head,restore the contour of the femoral head,and reconstruct the function of the femoral head to a greater extent.Delaying or avoiding hip replacement provides an effective new method for head-preserving treatment of advanced femoral head necrosis.In summary,this study firstly used human anatomy research methods to clarify the course,diameter and blood supply range of the musculoperiosteal iliac branch with the ascending branch of LCFA,and established its musculoskeletal flap according to the coordinate positioning of this blood vessel.Furthermore,through the finite element mechanical analysis method,this study clarified the optimal biomechanical adaptation position and angle of the musculoperiosteal iliac bone flap with the ascending branch of LCFA,and provided accurate guiding parameters for clinical bone flap transplantation.Based on the results of these two theoretical studies,we further confirmed in clinical studies that the accurate positioning of musculoperiosteal iliac bone flap with the ascending branch of LCFA and transplantation can significantly improve the functional recovery and preservation of the hip joint after ONFH.This study provides a new treatment idea and method for ONFH hip preservation therapy and the development of orthopaedic precision medicine. |
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