Research On Anatomy Basis And Clinical Application Of Total Hip Arthroplasty Using Direct Anterior Approach In Lateral Position

Chapter 1 The Applied Anatomy of Rectus Femoris Muscles in Direct Anterior Approach for Hip JointBackground and Objective:The direct anterior approach(DAA)is minimally invasive inter-muscular approach for total hip arthroplasty.Due to the irregular distribution of the front muscles around hip and adjacent relationship which can be affected by surgical position and traction during operation,the DAA is difficult to master in clinical practice.A long learning curve has been noted for surgeon in their early experience.It’s also difficult for doctors to identify the deep muscular interval.The deep inter-muscular spaces of DAA were composed of rectus femoris and anterior border of gluteus medius.The adjacent relationships of m.rectus femoris affect the whole exposure procedure in DAA.How to deal with m.rectus femoris and its adjacent relationship is the most important and difficult step to complete in DAA procedure.At present,there is a lack of relevant research.The purpose of this study was to observe the morphological anatomy of rectus femoris and its adjacent relationship during the exposure of direct anterior approach for hip joint.Materials and methods:Six adult wet cadavers fixed by formalin were dissected according to the procedures of the direct anterior approach.The morphological changes of rectus femoris and its adjacent anatomical relationship were recorded.Result:①The superficial interval of DAA is composed of the medial border of tensor fasciae latae and the lateral margin of sartorius muscle.The two muscles originate from the anterior superior iliac spine and form a conjoined tendon.There is no obvious muscle interval at the beginning.At the distance of(50 ± 5.6)mm from the anterior superior iliac spine,the two muscles begin to separate gradually and move towards the medial and lateral thighs respectively.The rectus femoris muscle belly passes through the bifurcation of sartorius muscle and tensor fasciae lata muscle,and it is located in the centre area of thigh.②The RF straight head originate from the AIIS,and the proximal part is located below the superficial conjoined tendon.The initial segment is about(50.3 ± 6.2)mm in length and(10±3.3)mm in width.It goes down the middle line of the anterior femoral region and the distal muscle abdomen runs under the median subcutaneous part of the thigh.The anterior superior part of m.Gm is located at subcutaneous and covers m.RF.There is no parallel relationship between the anterior edge of the middle gluteal muscle and the rectus femoris.It is necessary to pull the front edge of the middle gluteal muscle outward and upward to expose the interval between the middle gluteal muscle and the rectus femoris,thus reaching the front capsule,which is also composed of the deep interval of DAA.③The intersection of the RF two heads is about(20±3.5)mm from ASIS.The iliopsoas muscle moves from the upper side to the lower side and ends at the lesser trochanter of femur.The femoral nerve,femoral artery and femoral vein pass through the surface of iliopsoas muscle.④ The femoral artery divided into the deep branch femoral artery at(45±6)mm below the inguinal ligament.The deep femoral artery ran parallel to the main femoral artery about(30±5)mm and then sent out the LCFA.The LCFA ascending branch ascends along the lateral edge of rectus femoris to between rectus femoris and lateral femoris,and divides into 2～3 small branches and forms vascular network.⑤ The anterior capsule starts from the labrum of the upper edge of the acetabulum,completely envelops the whole front surface of head and neck,and ends at the intertrochanteric line.The rectus femoris covers the medial half of the capsule,and the head of the rectus femoris is healed with the anterior and upper part of the capsule.The medial part of the capsule can only be exposed by cutting the head of the rectus femoris with a sharp knife.Iliopsoas muscle runs backward and downward close to the anteromedial joint capsule,and ends at the femoral trochanter,and some iliopsoas muscle fibers end at the medial inferior joint capsule.Only by peeling off the iliopsoas muscle fiber attached to the joint capsule with a sharp knife can the space between iliopsoas muscle and the anterior joint capsule be exposed.The distal part of the anterior capsule is covered by vastus lateralis.⑥After resection of the anterior capsule,only a small part of the femoral head can be exposed.Most of the femoral head is located in the acetabulum and cannot be exposed directly.The area of the exposed part of the femoral head accounts for about 1/3～1/4 of the total area of the femoral head.It is difficult to lever out the femoral head from the front place after cutting the femoral neck.The anterior and medial surfaces of femoral neck can be fully exposed,and the neck osteotomy is also convenient.’Conclusion:Knowledge of the anatomic characteristics and adjacent structures of m.rectus femoris is helpful to improve surgical safety of DAA and shorten its learning curve.Chapter 2 The Radiographic Evaluation of Implant Alignment in Total Hip Arthroplasty using Direct Anterior Approach in Lateral PositionBackground and Objective:The direct anterior approach(DAA)utilizes the inter-muscular and inter-nervous planes to expose the hip joint with no muscle or tendon involvement.Total hip arthroplasty(THA)using the DAA provides many benefits to patients,although DAA applied in supine position is accompanied by increased complications and implant mal-positioning.To reduce potential risks associated with DAA-THA in supine position,some surgeons have attempted to apply the approach in lateral position and they presuppose that the latter can provide better exposure.However,there have been few comparative studies concerning the implant alignment with these approaches when the patient is placed in lateral position.The purpose of this study was to compare the difference in cup orientation and stem alignment in THA using posterior-lateral approach(PLA)with those using the DAA in lateral position.Materials and methods:A prospective controlled study was performed in 192 patients with end-stage hip arthritis admitted to our hospital from January 2015 to August 2016.These patients were randomly divided into two groups:102 patients were treated with THA using DAA in lateral position,and the other 90 patients were treated with THA using PLA.One senior orthopedic surgeon performed all operations but did not conduct the clinical follow-up.The mean follow-up time was 5.1 years(range,4.1～5.6 years)in the two groups.The postoperative anteroposterior pelvic radiographs and three-dimensional CT images were used to evaluate prosthesis alignment.The picture data is processed by Picture Archiving and Communication Systems(PAC)software.The cup radiographic anteversion angle,inclination angle,horizontal displacement of the rotation center of the hip(RCH),vertical displacement of the RCH,the rates of implantation in the safe zone of Lewinnek,the rates of implantation within the interval of the target angle,femoral anteversion,the matching degree of stem and the femoral medullary cavity,limb length discrepancy,femoral offset(FO)discrepancy,stem alignment in coronal plane and sagittal plane,periprosthetic fractures,dislocation,loosening and heterotopic ossification(HO)were evaluated in the two groups.Results:The mean At angle was 14.3° and 8.6° in DAA and PLA group respectively,P=0.001.The mean Ic angle was 41.3°and 41.5°in the two groups,P=0.454.96 cups(94%)in the DAA group and 83 cups(92%)in the PLA group were located in the safe zone of Lewinnek,P=0.602.82 cups(80.4%)in the DAA group and 59 cups(65.6%)in the PLA group achieved target At angle(P=0.020).90 cups(88.2%)in the DAA group and 73 cups(81.1%)in the PLA group were positioned within the interval of the target inclination angle(P=0.169).More cups were positioned within the interval of both the target anteversion angle and target inclination angle in the DAA group than in the PLA group(DAA:74 hips,72.5%,PLA:48 hips,53.3%,P=0.006).The mean horizontal displacement of the RCH in DAA group and PLA group was(0.80±0.13)mm and(0.73±0.11)mm respectively.This difference was not statistically significant(P=0.122).The mean vertical displacement of the RCH in DAA group and PLA group was(0.85±0.07)mm and(3.96±0.21)mm respectively.The difference was however statistically significant(P=0.031).Stem alignment in the coronal plane was not significantly in the neutral position in both groups(93.1%vs.94.4%,P=0.709),and stem alignment in the sagittal plane was also not significantly in the neutral position in both groups(92.2%vs.95.6%,P=0.332).The mean femoral anteversion angle was(11.2±1.3°)in the DAA and(11.80±1.1°)in PLA groups respectively.The difference was not statistically significant(P=0.708).89 stems(87.2%)representing in the DAA group and 78 stems in the PLA group were tightly packed with the femoral medullary cavity.This difference was not statistically significant(P=0.904).The discrepancy of FO and the rate of FO reconstruction were not statistically significant.(DAA:3.1mm,89.8%;PLA:2.9mm,88,9%;P=0.602).In the DAA group the mean limb length discrepancy was(2.5±0.5)mm,93 cases were less than 5 mm,with an acceptable rate of 91.2%.In the PLA group the mean limb length discrepancy was(2.8±0.3)mm,80 cases were less than 5 mm,and the acceptable rate was 88.9%.The difference was not statistically significant(P=0.596).In the DAA group the following complications were recorded:(1)One patient incurred greater trochanteric fracture which was sutured with wire intraoperatively and healed after three months and(2)another patient had a calcar fracture above the level of the lesser trochanter during stem implantation,which did not affect the stability of the stem,and received no additional treatment intraoperatively.In the PLA group the complications were one greater trochanteric tip fracture and 2 minor fissure calcar fracture.In the PLA group one postoperative dislocation due to excessive flexion of hip joint was noted and treated with closed reduction.There was no loosening or sinking of prosthesis in both groups until the last follow-up.7 patients in the DAA group had HO while 6 patients in the PLA group experienced HO.The difference was not statistically significant(P=0.957).Conclusion:(1)For the position of acetabular component,DAA in lateral position achieved superior anteversion angle and inclination angle,less vertical displacement of the RCH,and more accurate cup orientation compared to the PLA in total hip arthroplasty.(2)For the position of femoral component,DAA in the lateral position can maintain similar stem alignment compared to the PLA in total hip arthroplasty.The DDA with lateral position facilitates the adequate exposure of the proximal femur and decreases surgical risk.Chapter 3 Total Hip Arthroplasty in Lateral Position Directly Anterior Approach for patients with AS Hip ankylosis-An efficacy analysisBackground and objective:THA is the most effective treatment for patients with ankylosed hip.The anatomical and pathophysiological abnormalities of the ankylosed hip bring great difficulties to the surgical exposure and prosthesis installation.Compared with common replacement,THA for hip ankylosis is more difficult and risky.Therefore,it is particularly important to choose an appropriate surgical approach and position for ankylosing hip replacement to improve the exposure and reduce the surgical complications.Many studies reported that the DAA with patients in the lateral decubitus position can provide favorable exposure of the proximal femur and accompanied by satisfying clinical and radiographic results for ordinary hip diseases.However,it is still unclear whether the THA via DAA in lateral decubitus position can be clinically effective for the ankylosed hip in patients with AS.This research was to compare the efficacy of DAA-THA in lateral with conventional PLA-THA for AS patient.Materials and methods:From March 2014 to June 2018,128 AS patients with hip ankylosis were analyzed retrospectively,including 109 males and 19 females.With an average age of 43 years(26-66 years),88 had fibrotic ankylosis and 34 presented with osteogenic ankylosis.Based on the surgical procedures through which the patients underwent,they were grouped into two groups:72 patients of average age 43.6±11.3 years treated by direct anterior approach in the lateral position,and 56 patients(42.4±12.5)were treated by the traditional posterolateral approach.The incision length,operation time,blood loss,number of blood transfusion cases,creatine kinase(CK)level,increased value of C-reactive protein(ΔCRP),visual analog scale of pain(VAS),dosage of opioid analgesics used,total range of motion and flexion of hip joint,Harris score of hip joint,the superior rate of abductor muscle strength,BASFI(Bath Ankylosing Spondylitis Functional Index),the At and Ic angle of acetabular cup,the stem alignment,and surgical complications were analyzed.Results:The incision length of the DAA group was shorter than that of the PLA group[(8.6±1.6)cm and(12.8±1.8)cm respectively].The length of surgical procedure(DAA)was also shorter than that of the PLA group[(82±15)min and(96±19)min respectively].There was relatively lower blood loss in the DAA group(486±40 ml)compared to the PLA group(620±50 ml).This reflected in the lower incidence of blood transfusions for both groups(15 against 34 cases).the CK level of the DAA group was lower than that of the PLA group(506 u/L vs.972 u/L).The ΔCRP value of the DAA group was smaller than that of the PLA group[(32 ± 3.7)u and(45 ± 3.8)u,respectively].The VAS score was lower in DAA group on the 1 day and 5 day after operation.These differences on these days were statistically significant but not after 1 month.There were 43 cases(59.7%)in DAA group without morphine analgesic after operation,and that was 21 cases(37.5%)in PLA group.The difference was statistically significant(P=0.013).The total dose of opiates used was 3400 mg for the DAA group and 4600 mg for the PLA group(P=0.021).All patients were followed for 2～6 years.The average follow-up time was 4.3±1.4 years.In the DAA group,the total range of motion was 120.6°± 16.2° and the flexion was 74.7°±13.6°,and that in the PLA group was 90.5°±13.2° and 60.4°±11.4°respectively.The total ROM and the maximum flexion angle were similar in the two groups at 1 year and the last follow-up.One mont after operation,Harris score of the DAA group was 72.2± 5.3,while the PLA group was 63.8± 4.2,representing sastatistically significant difference.Two months after operation,the Harris score was higher in the DAA group(81.2 ± 5.2)than PLA group(78.8 ± 4.5).This difference was however not observed after 1 year.The superior rate of abductor muscle strength was 72%at 2 months and 86%at 6 months in the DAA group,and that in the PLA group was 31%and 54%respectively,showing a significant difference between the two groups.The observed difference was absent after 1 year.The BASFI scores was lower in both group at the last follow-up than pre-operation.The cup anteversion in DAA group(18.9°± 2.1°)was significantly higher than PLA group(12.6°± 1.9°).The incidence of stem neutral implantation was 91.7%in the DAA group,and 92.9%in the PLA group.There was no difference between groups in terms of the neutral implantation of stem.In the DAA group,observed complications included 2 femoral calcar fractures,1 trochanteric fracture and 1 tensor fasciae lata tear.In the PLA group,the complications included 2 femoral calcar fractures,3 acetabulum bone defects(2 posterior wall,1 anterior superior wall).In the DAA group the postoperative complications included 1 case of swelling,2 cases of deep vein thrombosis in the lower leg,and 2 cases of lateral femoral cutaneous nerve injury.The postoperative complications in the PLA group included 2 cases of posterior dislocation of hip joint,3 cases of deep vein thrombosis and 1 case of superficial infection.In the DAA group,8 hips(11.1%)developed heterotopic ossification,5 in Brooker Ⅰ class,3 in BrookerⅡ class.In the PLA group,15 hips(26.8%)developed heterotopic ossification,8 in Brooker Ⅰ class,6 in Brooker Ⅱ class,and 1 in Brooker Ⅲ class.The incidence of heterotopic ossification in the DAA group was lower than that of the PLA group(P=0.022).Conclusion:Patients with hip ankylosis who were treated by.total hip arthroplasty via DAA in the lateral position can achieve minor surgical trauma,fast recovery of hip function,acceptable surgical complications,and satisfactory clinical results.