The Hip Drop Physical Examination Test Can Be Used to Guide Advanced Imaging and Surgical Decision Making

Abstract

Purpose

To establish the clinical utility of the hip drop test (HDT) for diagnosing hip abductor tendon tears as well as for predicting future surgery and to identify patient risk factors associated with tears and surgery.

Methods

A single institution’s electronic medical records, comprising patients treated by a single sports medicine fellowship-trained orthopaedic surgeon, were reviewed to identify patients aged 18 years or older with suspected hip abductor tendon tears with documented HDT results who underwent hip magnetic resonance imaging (MRI). Hip MRI served as the diagnostic gold standard. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated, and logistic regression analysis of various associated factors was performed.

Results

Our initial review yielded 366 patients. After we excluded patients without positive or negative HDT results, as well as those without MRI results, 261 patients underwent analysis. Of these patients, 245 had negative HDT results whereas 16 had positive results. Of the patients with positive HDT results, 8 underwent surgery. Sensitivity for a future MRI-confirmed diagnosis of hip abductor tendon tear was 30.4% (95% confidence interval [CI], 19.1%-44.8%), and specificity was 99.1% (95% CI, 96.7%-99.7%). The PPV of the HDT for a future MRI-confirmed diagnosis was 87.5% (95% CI, 64.0%-96.5%), and the NPV was 86.9% (95% CI, 82.1%-90.6%). For the prediction of future hip abductor tendon surgery, a positive HDT result yielded a sensitivity of 80.0% (95% CI, 49.0%-94.3%), specificity of 96.8% (95% CI, 93.8%-98.4%), PPV of 50.0% (95% CI, 28.0%-72.0%), and NPV of 99.2% (95% CI, 97.1%-99.8%).

Conclusions

The HDT is a reliable clinical examination maneuver for diagnosing hip abductor tendon tears in patients with lateral hip pain when performed by an experienced medical provider. The HDT shows a high NPV for both a hip abductor tendon tear diagnosis on MRI and the prediction of future surgery and may be used to guide initial clinical decision making. Patients with lateral hip pain and negative HDT results may forego immediate advanced imaging and, instead, consider nonoperative management. Additionally, demographic variables such as female sex, older age, and higher body mass index raise the risk of a hip abductor tendon tear and thus increase suspicion for an abductor tendon tear requiring advanced imaging and, possibly, future surgery.

Level of Evidence

Level III, development of diagnostic criteria based on nonconsecutive patients.