Radiographic Parameters of Adult Hip Dysplasia

Abstract

As knowledge about the origin and morphologic characteristics of hip pain in the young adult has evolved, so too has the clinician’s ability to assess for various pathologies of the hip on radiographs, magnetic resonance imaging (MRI)/magnetic resonance arthrography (MRA), and computed tomography (CT). Because there is no algorithm at this time directly indicating what to do in more subtle hip morphologies, such as microinstability and borderline hip dysplasia (BHD), a skilled hip preservation specialist must use multiple imaging sources and know how to interpret them correctly. Imaging parameters used in the workup for hip dysplasia and BHD include the lateral center-edge angle, Tönnis angle, iliofemoral line, and presence of an upsloping lateral sourcil or everted labrum, among many others. The purpose of this narrative review was to detail various established criteria and parameters on anteroposterior pelvis plain radiographs, MRI/MRA, and CT that assist in defining the nature and severity of instability present in a dysplastic hip, thereby aiding in the development of patient-specific surgical treatment plans.

Noninterportal capsulotomy of hip arthroscopy showed improved outcomes in borderline hip dysplasia: A retrospective study with minimum 2‐year follow‐up

“…Therefore, additional measurements should be included to assist in the diagnosis of hip instability in cases of BHD. The acetabular bony coverage can be assessed with LCEA, ACEA, Tönnis angle, sharp angle, acetabular index, anterior and posterior wall index [6,37,43] and femoral epiphyseal acetabular roof index [21]. Moreover, parameters such as a broken Shenton line, excessive femoral anteversion (≥25°), femoral neck-shaft angle (≥135°), iliofemoral line and an upsloping lateral sourcil are all indications of hip instability [37,43].…”

“…The LCEA, ACEA, ⍺ angle, Tönnis angle and Tönnis classification of osteoarthritis were obtained from the images. LCEA was defined as the angle between the line from the centre of the femoral head to the edge of the acetabulum and the vertical line through the centre of the femoral head on the standing anteroposterior pelvis view [43], while the ACEA was measured on the false‐profile view [6]. The ⍺ angle was measured on the AP view of the pelvis as the angle between two lines—the first line was drawn from the centre of the femoral head to the point where the lateral edge of the femoral head departed from the best fitting circle around the femoral head, while the second line was drawn from the centre of the femoral head to the centre of the femoral neck [43].…”

“…LCEA was defined as the angle between the line from the centre of the femoral head to the edge of the acetabulum and the vertical line through the centre of the femoral head on the standing anteroposterior pelvis view [43], while the ACEA was measured on the false‐profile view [6]. The ⍺ angle was measured on the AP view of the pelvis as the angle between two lines—the first line was drawn from the centre of the femoral head to the point where the lateral edge of the femoral head departed from the best fitting circle around the femoral head, while the second line was drawn from the centre of the femoral head to the centre of the femoral neck [43]. The Tönnis angle was defined as the angle between the horizontal line of the transverse pelvic axis and the line from the medial edge of the sclerotic sourcil to the most lateral point of the sourcil [43].…”

“…The ⍺ angle was measured on the AP view of the pelvis as the angle between two lines—the first line was drawn from the centre of the femoral head to the point where the lateral edge of the femoral head departed from the best fitting circle around the femoral head, while the second line was drawn from the centre of the femoral head to the centre of the femoral neck [43]. The Tönnis angle was defined as the angle between the horizontal line of the transverse pelvic axis and the line from the medial edge of the sclerotic sourcil to the most lateral point of the sourcil [43]. Chondral damage, labral lesion(s), acetabular labral hypertrophy and LT tears were evaluated using magnetic resonance imaging (MRI).…”

“…Borderline hip dysplasia (BHD) is a condition that falls between a normal hip joint and hip dysplasia and may present as hip pain and microinstability due to intra‐articular pathology or architectural and functional abnormalities [10]. The lateral centre‐edge angle (LCEA), which measures the degree of lateral acetabular coverage, is commonly used for plain radiographic measurement of BHD, in which the angle measures between 20° and 25° [43]. The LCEA, however, provides insufficient clues about hip morphology and function [31].…”