Treatment Of Posterolateral Tibial Plateau Fractures Through A Modified Posterolateral Approach

Background: The posterolateral tibial plateau fracture has been given little attention in the literature,but now with the increased usage of CT scan for intra-articular fractures,the incidence of these fractures is not as low as it was thought before.The exposure and fixation of the posterolateral column fractures of the tibial plateau is a challenging process due to the complex anatomy of the tibial plateau posterolateral corner.Furthermore,the biomechanical management principles of these fractures demand anatomic articular reduction and anti-glide buttress plate fixation on the tibial plateau posterior aspect.The reduction and adequate fixation of these fractures is difficult to achieve through a lateral or anterolateral approach due to a lack of direct visualization of the posterolateral quadrant of the tibial plateau.Bhattacharyya described an extensile posterior approach to treating posterior shearing tibial plateau fractures.However,this approach required a large skin flap with extensive medial dissection and dissection of the medial head of the gastrocnemius.Trickey introduced popliteal midline S-shaped incision.As the elevation of a large skin flap for visualization is required in this approach,injury to the sural cutaneous nerve is much more likely to occur.The standard posterolateral approach,which was originally described by Lobenhoffer requires a fibular neck osteotomy and release of the posterolateral corner which can lead to potential fibular osteotomy nonunion,and considerable trauma to the soft tissue caused by extended dissection of the soft tissue(the joint capsule and meniscotibial(coronary) ligaments).Carlson reported a posterolateral curvilinear S-shaped approach.This approach was less invasive;however,the surgical field was limited.Tao developed a modified posterolateral approach involving an Lshaped skin incision.However,during the fracture reduction or plate fixation for complicated types of fractures,the popliteal artery was easily injured.Chang presented a modified posterolateral approach without fibular osteotomy to the dorsal parts of the proximal tibia.Although this approach produced comparatively less damage to the soft tissues,the surgical field was limited as it was very difficult to extend distally.To overcome these problems,Frosch introduced a modified posterolateral approach.This approach involved lateral arthrotomy to see the joint surface and the fracture reduction was achieved through posterolateral dissection without fibular osteotomy.This approach protects the soft tissue and important ligaments in the posterolateral area.Objective: The purpose of this study was to retrospectively review and evaluate the outcome of surgically treated posterolateral tibial plateau fractures using a modified posterolateral approach without fibular osteotomy.Methodology: 10 patients with tibial plateau fractures involving the posterolateral corner treated with open reduction and internal fixation through a modified posterolateral approach were retrospectively reviewed and clinically evaluated between Jan 2012 to Dec 2016.Cases with pathological fractures,open fractures,compartment syndrome,or those with neurovascular injuries of the lower extremity were excluded from this study.Before surgery details of the patients such as age,sex,mechanism of injury,side of injury,associated injury,and soft tissue injury were collected.The standard X-ray radiographs,computed tomography(CT)scans and three-dimensional(3D)reconstructions of all the patients were obtained preoperatively.The Orthopedic Trauma Association(AO/OTA)classification and coding system was used to classify all the fractures in this study.Then the intraoperative details like time to surgery(days),operation time(min),bone graft,intraoperative reduction were collected.Finally,the postoperative details like follow-up time(months),time of fracture healing(weeks),complications,the range of motion(ROM)and Hospital for Special Surgery(HSS)knee score were collected and evaluated.Results: 1 case was diagnosed with a pure split fracture and was classified as 41-B1.1 according to the Orthopedic Trauma Association(AO/OTA)classification and coding system,7 cases were diagnosed with splitdepression fractures and were classified as 41-B3.1 fractures,1 case was diagnosed with articular multifragmentary fracture and was classified as 41-C3.1,and 1 case was diagnosed with posterior bicondylartibial plateau fracture.The patients consisted of 7 males and 3 females,at a mean age of 45 years (range: 27-67 years).All of the patients sustained the injury in road traffic accidents.The fractures involved 5left knees and 5 right knees.Associated skeletal injury included fibular head fractures,ankle fracture,pelvic fracture,scapula fracture,olecranon fracture,and parietal bone fracture.Associated soft tissue injury included bruising/contusion,lateral meniscal injury,and anterior cruciate ligament injury.All the associated skeletal and soft tissue injuries were managed accordingly The mean time from initial injury to surgery was 10 days(range: 4 to 30 days).The average operation time was153.3 minutes(range: 120-240 minutes).The autogenous bone graft was used in 6 patients to support the reduced depression type of fractures.The mean postoperative value of FTA was 172.70±2.35,the mean value of MPTA was 90.10±2.33,and mean value of LPSA was 10.00±2.66.None of these radiologic parameters showed a significant change when they were measured during the follow-up(p-value > 0.05).A satisfactory anatomic reduction was obtained in all of the patients.All patients were followed up for an average period of 18.8 months(range: 6-40 months).Mean bone union time was 13 weeks(range: 11-14 weeks)and mean full weight-bearing time was 12 weeks.Good fracture healing was observed in all of the patients.The average range of motion(ROM)of the knee was 1° of knee extension(range: 0°-5°),and mean flexion of the knee was 125.8°(range: 120°-135°),and the average HSS score was 91.8 points(range: 85-96)at the final follow-up.No specific approach-related complications such as injury to the common peroneal nerve were documented.No loss of reduction was observed during the follow-up.Conclusion: It is concluded that the modified posterolateral approach provides direct and complete exposure of the fracture site,help to achieve anatomic fracture reduction and stable internal fixation.By using this modified approach satisfactory clinical and radiological outcome can be attained.