Imaging validation of the San José Hospital sign in the physical examination of the antero-lateral instability of the knee

Abstract

Background: The clinical sign for instability of San José hospital is a variant of the pivot shift, described by the lead author, for the diagnosis of the anterior lateral instability of the knee. It is a clinical test, well tolerated by the patient that can be easily performed by an orthopaedic surgeon. The objective of this study was to determine the diagnostic validity of the San José Hospital sign on the physical examination to determine anteroposterior instability of the knee due to anterior cruciate ligament injury as compared to MRI as a reference standard.
Materials and methods: A study of the diagnostic tests performed on patients who attended a knee clinic and underwent the San José Hospital sign manoeuvre was conducted blindly and independently of the results of MRI. The sign was performed by orthopaedic surgeons with experience in knee surgery and with formal training to perform the manoeuvre.
Results: The study included 176 patients. The median age was 34.5 years (IQR: 26-51 years), and 63.1% were males. Magnetic resonance imaging showed that 88 patients had a rupture of anterior cruciate ligament. The Hospital of San José sign was positive for 80 patients. The sensitivity of the San José Hospital sign was 90.9% (95% CI: 82.9-96.0) and the specificity was 100% (95% CI: 95.9-100). The negative likelihood ratio (LR) was 0.1 (95% CI: 0.04-0.17).
Discussion: This manoeuvre is a valid clinical tool for the diagnosis of anteroposterior instability of the knee secondary to the anterior cruciate ligament injury, enabling the examination to be made with much less apprehension than when executed using the traditional manoeuvres.
Level of evidence: II.