The Effect Of Acetabular Fractures On The Biomechanics Of The Hip Joint And Related Research

Objectives: Fractures of the acetabulum are serious intraarticular injures.Several factors contribute to the outcome of patients with a displaced acetabularfracture: fracture type, patient age, associated hip dislocation, injury to the femoralhead, quality of reduction, and the development of significant heterotopic ossificationand/or avascular necrosis. Although many of these factors are beyond the control ofthe treating orthopedic surgeon, intraarticular fracture displacement can be improvedwith open reduction and internal fixation. It has been clearly shown in large clinicalseries that anatomic reduction of displaced acetabular fractures involving the superioracetabulum decreases the incidence of posttraumatic osteoarthrosis. The extensiveclinical work of many scholars has detailed the fracture classification, surgicalapproaches, strategies for reduction and fixation, and preliminary data on early andlong-term outcomes. Nonetheless, there is still considerable controversy concerningthe criteria for operative treatment, and the maximum amount of articulardisplacement and the type of displacement that can be accepted and will still allow asatisfactory clinical result following acetabular fractures. Most scholars agreed thatthe indications for operative treatment are 3mm or greater displacements of fracturesin the weight-bearing dome of the acetabulum, incarcerated osteochondral fragmentwith a nonconcentric reduction, 40% involvement of the posterior wall associatedwith instability of the hip joint, and sciatic nerve injury need operative exploration.These criteria come from clinical experiences of many scholars, especially Matta'swork. Matta et al., in a retrospective clinical review, found an increased incidence ofpost-traumatic arthritis in patients with greater than 3mm displacement. In a follw-upstudy, Matta reported that a reduction of less than 3mm displacement provided betterlong-term clinical result. So they made the 3mm displacement as the division ofoperation and non-operation and the criteria of evaluating clinical results. The criteriafor the posterior wall fractures were ascertained by affecting the stability of the hip 8英 文 摘 要joint. These criteria were not testified by biomechanical data. Moreover, the effect ofacetabular fracture displacement on the load transmission across the hip joint isunknown. In addition, the acetabular labrum is a fibrocartilagious structure attachedto the acetabular rim. Acetabular labral tears have been described as a biomechanicalcause of hip pain in patients, especially in young patients. But the role of acetabularlabrum in load transmission in the hip joint is not clarity. We undertook a seriesbiomechanical study to measure the effect of the posterior wall acetabular fractures,transtectal transverse acetabular fractures, high anterior column acetabular fractures,and acetabular labrum on the mechanics of the hip joint. Method:Nineteen embalmed pelves and articulated proximal 1/3 of the femurswere harvested for this study. Simulated posterior wall acetabular fractures wereevaluated in four specimens (six hips). Simulated transtectal transverse acetabularfractures were tested in five specimens (nine hips). Simulated high anterior columnacetabular fractures were tested in five specimens (nine hips). The function of theacetabular labrum was tested in five specimens (nine hips). The specimens werecleaned of soft tissues, leaving the pelvic ligaments and capsules of both hip jointsintact. The position of the pelvis and proximal femur during testing simulated thesingle leg stance phase of gait. The plane formed by the anterior superior iliac spineand the pubic symphysis aligned vertically. The line between iliac crests washorizontal. In the frontal plane, the femoral shaft was placed in 15 degrees ofadduction relative to the pelvis. In the sagittal plane, the femoral shaft was vertical.The femur was oriented in 5 to 10 degre...