A new study assessed the diagnostic value of ultrasound and of ultrasound-guided intra-articular injections of the hip in diagnosing femoroacetabular impingement in patients with atypical symptoms.
This new study assessed consecutive patients diagnosed with femoroacetabular impingement syndrome and atypical symptoms who underwent an ultrasound-guided intra-articular injection of the hip between January 2017 and February 2019. All patients underwent a systematic clinical examination, ultrasound and MRI examination and, finally, an ultrasound-guided intra-articular injection of the hip. Patients who had a positive response to the injection underwent hip arthroscopy to treat the intra-articular lesions. The sensitivity, the specificity, the accuracy and the positive predictive value of ultrasound and of MRI were calculated against the arthroscopic findings. Pre-operative and post-operative results from the Visual Analog Scale for pain and the Modified Harris Hip Score were also assessed.
A total of 78 patients with atypical symptoms who were considered to be suffering from femoroacetabular impingement were included. Of these, 50 had a positive response to the injection and 28 a negative one. In the end, 36 patients underwent hip arthroscopy. The response to intra-articular injection of the hip was 91.7% for detecting intra-articular pathology. There were no adverse effects or complications from these injections. The sensitivity, the specificity and the positive predictive value of ultrasound in diagnosing cam-type femoroacetabular impingement were 82.9%, 80.6% and 96.7% respectively. The sensitivity and the specificity of ultrasound in diagnosing a tear of the anterosuperior labrum were 72.2%. MRI had a specificity, a positive predictive value and an accuracy of 72.2%, 96.3% and 74.3% respectively for diagnosing femoroacetabular impingement, while for diagnosing a labral tear the sensitivity and the accuracy were 88.9%.
The authors concluded that ultrasound examination and ultrasound-guided intra-articular injection of the hip are highly accurate in diagnosing femoroacetabular impingement in patients with atypical symptoms.
Source: “Arthroscopy”, January 2021
