Preoperative planning for redirective, periacetabular osteotomies

Abstract

Redirective, periacetabular osteotomies (PAO) represent a group of surgical procedures for treatment of developmental dysplasia of the hip (DDH) in skeletally mature and immature patients. The ultimate goal of all procedures is to reduce symptoms, improve function and delay or prevent progression of osteoarthritis. During the last two decades, the understanding of the underlying pathomechanisms has continuously evolved. This is mainly attributable to the development of the femoroacetabular impingement concept that has increased the awareness of the underlying three-dimensional complexity associated with DDH. With increasing knowledge about the pathobiomechanics of dysplastic hips, diagnostic tools have improved allowing for sophisticated preoperative analyses of the morphological and pathobiomechanical features, and early recognition of degenerative changes, which may alter the long-term outcome. As redirective, PAO are technically demanding procedures, preoperative planning is crucial to avoid intraoperative obstacles and to sufficiently address the patient-specific deformity. Although conventional radiography has been used for decades, it has not lost its primary role in the diagnostic work-up of patients with DDH. Furthermore, an increasing number of modern imaging techniques exists allowing for assessment of early cartilage degeneration (biochemical magnetic resonance imaging) as well as 3D planning and computer-based virtual treatment simulation of PAO. This article reviews the literature with regard to the current concepts of imaging of DDH, preoperative planning and treatment recommendations for redirective, PAO.

Characterization of version in the dysplastic hip and the need for subsequent femoral derotational osteotomy after periacetabular osteotomy

“…Hip instability can be very challenging to diagnose, and using radiographic CEA alone may not adequately define acetabular coverage. Utilization of preoperative 3D CT has given us the ability to comprehensively analyze both acetabular and femoral-sided anatomy of hip dysplasia [ 6 ], which has resulted in a better understanding of each patient’s anatomy for diagnostic purposes and for pre-surgical planning of acetabular reorientation. Prior literature has not clearly elucidated the differences in AcetV and FV seen in dysplastic hips when compared with non-dysplastic hips, and the relationship between AcetV and FV within a dysplastic hip has not been defined.…”

“…As such, we do not have a clear understanding of all the nuances of how a dysplastic hip differs from a non-dysplastic hip, and how FV abnormalities contribute to the post-operative course after periacetabular osteotomy (PAO). The increasing utilization of 3D computed tomography (CT) has allowed us to visualize and measure the AcetV and FV in the dysplastic hip to identify the exact orientation and individual anatomy of the hip joint [ 6 ]. A better understanding of how dysplastic hips differ from non-dysplastic hips in both AcetV and FV, and whether FV contributes to the post-surgical recovery can help us approach diagnosis and the ideal correction of symptomatic acetabular dysplasia, as well as indicate whether or not we should be addressing FV abnormalities at the same time as acetabular reorientation.…”

Overcorrection of the acetabular roof angle or anterior center–edge angle may cause decrease of range of motion after curved periacetabular osteotomy

“…This may depend on the type of dysplasia. The Tönnis sourcil angle of sloping roof dysplasia may be corrected to neutral, with enough lateral CE angles; however, the sourcil angle of short roof dysplasia, which has a normal Tönnis sourcil angle, may be corrected to neutral, without enough lateral CE [ 24 , 25 ]. If the fragment of short roof dysplasia is moved into further abduction, the lateral CE may increase; however, the Tönnis sourcil angle would become overcorrected, which increases the risk for femoroacetabular impingement.…”

System‐specific evaluation of the dual flip angle MRI technique for quantitative T1 measurement

“…In addition, a method to perform a system‐specific calibration of the DFA technique, to be performed, if needed, is also presented. This study would be beneficial not only for the purpose of improving the accuracy of the DFA technique on any particular MRI system, but also for the purpose of maintaining the consistency in a multi‐system clinical MRI suite, especially when the results, regardless of the specific MRI system to be used, are intended to be utilized to make a clinical decision, such as in the clinical dGEMRIC studies 18,19 …”