The Anatomy Studies And Clinical Application Of Direct Posterior Approach In The Treatment Of Posterior Acetabular Fractures

Background:The treatment of acetabular fractures has always been a great challenging work for orthopedic trauma surgeons due to the complex region of anatomy and irregular bone morphology of acetabulum.For the posterior acetabular fracture involving the posterior wall or posterior column,the risk and the difficulty of operation are undoubtedly increased by the adjacent superior gluteal neurovascular bundle,sciatic nerve,medial circumflex femoral artery and other tissues.At present,the common surgical approaches for the treatment of posterior acetabular fractures include classical Kocher-Langenbeck(K-L)approach,modified Gibson approach,the trochanteric flip osteotomy and modified K-L approach.However,these approaches might be suboptimal because of the longer learning time,greater surgical trauma or the high rate of operative complications.Therefore,in view of the shortcomings of the current surgical approaches and anatomical characteristics of the hip,a novel approach called Direct posterior approach was proposed by us,which can directly expose the posterior aspect of the acetabulum through the muscle space and achieve reduction and internal fixation of the fractures.Its advantages include decreasing surgical trauma,shortening operation time,reducing intraoperative bleeding and decreasing occurrence of surgical complications.We supposed that this approach can obtain a good effect during its clinical application.Purpose:This study aims to measure the safe exposure rang of the acetabulum via direct posterior approach and evaluate its safety in the treatment of posterior acetabular fractures;to explore its surgical technique and compare the clinical effect of direct posterior approach and K-L approach in surgical treatment of posterior acetabular fractures.Methods:1.Six fresh cadaver specimens were collected,and the direct posterior approach was performed to simulate the surgical procedure on both sides of the buttocks.The exposure rang of the posterior acetabulum was measured and the related anatomical parameters of the superior gluteal neurovascular bundle and the sciatic nerve were recorded.2.From January 2016 to June 2017,data of 10 cases with posterior acetabular fractures treated by direct posterior approach were retrospectively analyzed.The data of intraoperation and post-operation were collected,and the function of hip joint at the last follow-up was assessed by the Merle d’Aubigne-Posteal score modified by Matta.3.From January 2012 to June 2018,data of 45 cases with posterior acetabular fractures were retrospectively analyzed,including 24 cases of classical K-L approach from January 2012 to January 2017 and 21 cases of direct posterior approach from January 2016 to June 2018.The data of intraoperation,post-operation and follow-ups were compared between the two groups.Results:1.The exposure of the entire acetabular posterior wall,partial hip capsule and the great mass of the posterior column(from the superior margin of the greater sciatic foramen to the sciatic spine)was achieved by the direct posterior approach,with its average incision length of 9.82 mm.The average distances from the intersection of the greater sciatic notch with the superior gluteal artery,the superior gluteal vein,the superior gluteal nerve,to the apex of the greater sciatic notch were 10.55 mm,15.02 mm,3.00 mm respectively.The distances from the intersection of the lateral edge of the sciatic nerve with the upper and lower edges of the piriformis,to the apex of the greater sciatic notch were 18.85 mm,28.06 mm respectively.2.The average incision length,operation time,intraoperative blood loss and the fracture healing time of 10 patients were 9.6 cm,50 min,310 ml and 9.3 weeks respectively.According to the Matta imaging criteria for reduction quality,7 cases were excellent and 3 cases were good.Basing on the modified Merle d’Aubigne-Postel scoring system for the functional recovery of the affected hip at the last follow-up,6 cases were excellent,2 cases were good and 2 were fair.3.The group of the direct posterior approach reposed significantly shorter operation time,less intraoperative bleeding and shorter incision length than the group K-L approach(P<0.05).There was also significant difference in hip function at the last follow-up between the two groups(P<0.05),but there was no significant difference in reduction quality and average fracture healing time between the two groups(P>0.05).Conclusions:The direct posterior approach for posterior acetabular fractures can directly expose the posterior part of the acetabulum through gluteus medius-piriformis interspace without breaking the external rotator muscles.It can not only provide adequate and safe exposure for surgery,but also avoid iatrogenic damage to the peripheral nerve,vessel and tissue.Moreover,it can obtain satisfactory clinical results.Therefore,the direct posterior approach can be seen as a good choice for the treatment of the posterior acetabular fractures,which is worth to be further promoted and researched.