Le Fort I型截骨术定位平面的应用解剖学研究

目的：研究Le Fort I型截骨术与上颌牙根尖的关系,为临床合理制订截骨平面提供解剖学依据。方法：选择上颌牙槽清晰或出土后仍有牙保留的颅骨,在颅骨梨状孔下缘至上颌结节作一连线作为模拟Le Fort I型术式截骨水平,以上颌牙槽缘为标志,用游标卡尺测量每侧上颌各牙的牙槽缘至上述模拟截骨水平的距离及牙槽缘至各牙根尖端的长度,然后计算出上颌各牙根尖至Le Fort I型术式截骨线的距离。结果：上颌各牙相对的牙槽缘至Le FortI型术式截骨线的距离,从中切牙至第二磨牙逐渐缩小,右侧中切牙为21．09±1．53mm,左侧中切牙为20．96±1．64mm,右侧第二磨牙为14．94±1．52mm,左侧第二磨牙为14．95±1．59mm;上颌各牙根尖至Le Fort I型术式截骨水平的距离,从中切牙至第二磨牙也逐渐缩小,而两侧尖牙牙根尖距离Le Fort I型术式截骨线的距离右侧为4．49±1．74mm,左侧为4．69±2．14mm,第二磨牙牙根尖距离Le Fort I型术式截骨线的距离右侧为4．65±1．63mm,左侧为4．49±1．89,两侧尖牙牙根尖和第二磨牙牙根尖至Le Fort I型术式截骨水平的距离均比较接近。结论：上颌各牙根尖至LeFortI型术式截骨线的距离均在4mm以上,根据前牙中尖牙牙根尖的位置和后牙中第二磨牙牙根尖的位置,Le Fort I型术式截骨线水平在13、23（3｜3）根尖及27、27（7｜7）根尖上方4mm以上,按此平面作截骨水平较为安全,不易损伤牙根。     

Joint contact stresses calculated for acetabular dysplasia patients using discrete element analysis are significantly influenced by the applied gait pattern

Gait modifications in acetabular dysplasia patients may influence cartilage contact stress patterns within the hip joint, with serious implications for clinical outcomes and the risk of developing osteoarthritis. The objective of this study was to understand how the gait pattern used to load computational models of dysplastic hips influences computed joint mechanics. Three-dimensional pre- and post-operative hip models of thirty patients previously treated for hip dysplasia with periacetabular osteotomy (PAO) were developed for performing discrete element analysis (DEA). Using DEA, contact stress patterns were calculated for each pre- and post-operative hip model when loaded with an instrumented total hip, a dysplastic, a matched control, and a normal gait pattern. DEA models loaded with the dysplastic and matched control gait patterns had significantly higher (p = 0.012 and p < 0.001) average pre-operative maximum contact stress than models loaded with the normal gait. Models loaded with the dysplastic and matched control gait patterns had nearly significantly higher (p = 0.051) and significantly higher (p = 0.008) average pre-operative contact stress, respectively, than models loaded with the instrumented hip gait. Following PAO, the average maximum contact stress for DEA models loaded with the dysplastic and matched control patterns decreased, which was significantly different (p < 0.001) from observed increases in maximum contact stress calculated when utilizing the instrumented hip and normal gait patterns. The correlation between change in DEA-computed maximum contact stress and the change in radiographic measurements of lateral center-edge angle were greatest (R² = 0.330) when utilizing the dysplastic gait pattern. These results indicate that utilizing a dysplastic gait pattern to load DEA models may be a crucial element to capturing contact stress patterns most representative of this patient population.     

Towards patient-specific medializing calcaneal osteotomy for adult flatfoot: a finite element study

Clinically in medializing calcaneal osteotomy (MCO), foot and ankle surgeons are facing difficulties in choosing appropriate surgical parameters due to the individual differences in deformities among flatfoot patients. Traditional cadaveric studies have provided important information regarding the biomechanical effects of tendons, ligaments, and plantar fascia, but limitations have been reached when dealing with individual differences and tailoring patient-specific surgeries. Therefore, this study aimed at implementing the finite element (FE) method to investigate the effect of different MCO parameters to help foot and ankle surgeons performing patient-specific surgeries. This study constructed FE models of a flatfoot and a healthy foot based on computed tomography (CT) images. After validating the FE models with experimental measurements, differences in plantar stress were compared between two models and a criterion was established for evaluating the performance of surgical simulations. Four MCO parameters were then studied through FE simulations. Results suggested that the transverse angle, β, and translation distance, d, affected surgical performance. Therefore, special attentions may be recommended when choosing these two parameters clinically. However, the sagittal angle, α, and osteotomy position, p, were found to have less effect on the MCO performance.     

Combined Surgical Approach to Young Adults with Hip Dysplasia and Concomitant Intra-Articular Pathology Using Intra-Abdominal Monitoring

BackgroundCombined hip arthroscopy and periacetabular osteotomy (PAO) allows for treatment of intra-articular hip pathology with simultaneous correction of acetabular version and femoral head coverage in patients with symptomatic hip dysplasia. Currently, scant data is available to surgeons regarding optimal technique, sequence of repair, perioperative management, and the use of intra-abdominal monitoring in patients undergoing these combined procedures. The purpose of this study is to describe a two-surgeon, muscle-sparing, approach for sequential hip arthroscopy and PAO for the treatment of adults with acetabular dysplasia and concomitant intra-articular hip pathology.MethodsIn this article, we present the indications for combined hip arthroscopy and PAO, in addition to patient set-up and positioning. A detailed discussion of hip arthroscopy and a muscle sparing PAO techniques are then presented, with overview of a novel intra-abdominal pressure monitoring technique and post-operative rehabilitation protocol.ResultsThrough technical refinement and experience, our indications and protocol for the treatment of patients with symptomatic acetabular dysplasia with concomitant intra-articular hip pathology involves a refined and reproducible, two surgeon procedure utilizing hip arthroscopy followed by PAO. The use of intra-abdominal monitoring allows for assessment of intra-peritoneal pressures to monitor for the development of abdominal compartment syndrome secondary to fluid extravasation.ConclusionThe performance of concomitant hip arthroscopy and PAO for concurrent hip dysplasia and intra-articular hip pathology represents an increasingly common approach in hip preservation surgery. The hip arthroscopy and muscle-sparing PAO protocol using intra-abdominal monitoring described here serves to further refine and advance the indications and technical aspects of this challenging procedure.Level of Evidence: V