Sonography-Based Determination of Hip Joint Anterior Alpha-Angle: A Reliable and Reproducible Method

Abstract

Purpose Femoroacetabular impingement (FAI) is a known risk factor for hip osteoarthritis. The gold standard for diagnostics is X-ray and MRI. The accuracy of hip joint alpha angle measurements obtained using sonography is equal to measurements in MRI for patients with cam impingement of the hip joint. Materials and Methods Patients with hip pain and MRI and sonography were evaluated between January 2015 and December 2019 in a single center. Musculoskeletal sonography was performed according to the DEGUM guidelines by ultrasound-certified specialists. Measurements were repeated three times by two independent investigators. Results 285 patients were screened, and 110 patients (49 females, 61 males) met the inclusion criteria. The mean age at time of investigation of 54 left and 56 right hip joints was 54.2 years. 1320 measurements were performed. The mean alpha angle was 50.7° in MRI and 50.4° in sonography with a mean difference of 0.28° (p>0.05). Conclusion Determining hip alpha angle using sonography is a safe and reproducible method. No statistically significant differences between results in MRI and sonography could be seen. Although this is a retrospective, single-center study including only Caucasian mid-Europeans and with the known limitations of ultrasound imaging, it nevertheless shows that sonography can be used as a simple, cheap, and fast technique to assess the hip alpha angle without losing diagnostic quality.

Association of Chondrolabral Lesions with Ultrasound-Guided Detection of Pathological Head–Neck Contour

“…Based upon the recommendation proposed by Schamberger et al, the hip joint was clinically examined by an attending physician for orthopedic and trauma surgery [1]. The clinical examination included a passive and active range of motion, the FABER test, the FADIR test, and the anterior impingement test [13,14].…”

“…The femoral neck is positioned parallel to the upper screen margin, and the bone surface of the femoral neck must appear homogenous and hyperechoic [15]. For cam-evaluation, the transducer must be positioned anteriorly above the highest point of the femoral head [1,15,16]. Due to the acetabular edge, the bump cannot be seen during the internal rotation of the hip, and the evaluation of the head of the femur is impossible to extend to a full circle [1].…”

“…Femoroacetabular impingement syndrome (FAI) is a common pathology in the clinical setting of orthopedics [1][2][3]. Femoroacetabular impingement refers to the abnormal morphology of the hip joint characterized by pathological contact between the anterior upper femoral neck and the acetabulum [4].…”

“…In addition to diagnostic benefits, real-time imaging with ultrasound allows for dynamic loading tests of the hip joint during movement, which can be valuable, especially in assessing impingement-related abnormalities [8,9]. Moreover, ultrasound is a non-invasive procedure, making it suitable for repeated examinations and follow-up assessments [1]. Based on an ultrasound-based evaluation of the hip joint and its advantages, early intervention and preventive measures may be enacted for patients at increased risk of FAI-related complications.…”

“…Based on an ultrasound-based evaluation of the hip joint and its advantages, early intervention and preventive measures may be enacted for patients at increased risk of FAI-related complications. In summary, ultrasound examination demonstrates great potential as a valuable tool for the diagnosis and monitoring of femoroacetabular impingement syndrome due to its cost-effectiveness, avoidance of ionizing radiation, and capability for dynamic imaging [1,[9][10][11].…”