The Related Research Of Direct Anterior Total Hip Arthroplasty Incision Improvement And Lateral Femoral Cutaneous Nerve Injury

Background Direct anterior approach(DAA)hip arthroplasty is increasingly recognized by orthopedic surgeons around the world because of its good clinical effects.The DAA approach exposes the hip joint through the muscle and soft tissue gap.Compared with the traditional posterior approach(PA),it has significant advantages such as lower dislocation rate,less muscle damage,and faster postoperative recovery.However,anterior hip surgery often has the risk of the lateral femoral cutaneous nerve(LFCN)injury.LFCN is a simple sensory nerve originating from L2 and L3,which penetrates the front of the thigh and is usually divided into two or more branches.Although LFCN injury will not cause obvious limitation of postoperative function of the patient,it will cause burning sensation,dull pain,and numbness in the anterior and lateral thigh of the patient,which will affect the quality of life of the patient.Therefore,it is very important to reduce the incidence of LFCN injury after DAA.Objective To explore the anatomical relationship between DAA modified incision,DAA classic incision and lateral femoral cutaneous nerve using anatomical method.We use retrospective research methods to compare the incidence and functional difference of LFCN injury after DAA modified incision and DAA classic incision.MethodSelect 6 formalin corpses,4 females and 2 males,and use anatomical method to carefully trace the LFCN trunk and all branches in the anterolateral thigh.Determine the anatomical relationship between LFCN and DAA classic incision approach and DAA modified incision approach,and use a vernier caliper to measure the closest distance between LFCN and the incision.At the same time,retrospective analysis of DAA classic incision(from 2016 to 2017,13 males,12 females,age 21-68years,average 48.6 years,average BMI 24.42kg/m~2)and DAA incision improved(from2019 to 2020),13 males and 12 females,aged 27-62 years,average 44.6 years,average BMI 24.15kg/m~2)The incidence of LFCN injury and the recovery of injury symptoms after DAA.The FJS-12 score was used to evaluate the degree of patients forgetting the artificial hip joint before and after the incision modification,so as to simply and effectively evaluate the functional difference before and after the modified incision.Result Among the 6 autopsy results,according to Rudin’s LFCN classification of the front thigh,the sartorius muscle type accounted for 3/6(50%),the posterior type accounted for 2/6(33.3%),and the fan type accounted for 1/6(16.7%).At the same time,we found that the classic DAA incision and LFCN overlap,and there is a risk of injury.The DAA modified incision can avoid the trunk and all branches of LFCN.After the measurement,the shortest distance between the modified incision and LFCN is 1.2cm,with an average of 2.0±0.40cm.After the modified incision,the incidence of LFCN injury symptoms was reduced from 3/25(12%)to 1/25(4%),and 4/4(100%)of patients with LFCN injury were completely relieved.FJS-12 scores were similar at1 year after operation,and the difference was not statistically significant(p>0.05).Conclusion This study combined anatomical and clinical retrospective research results showed that the DAA modified incision can effectively reduce the incidence of LFCN injury without affecting postoperative function.