Diagnostic Accuracy of Physical Examination Tests in Core Muscle Injury

Abstract

Background: Core muscle injury (CMI), often referred to as a sports hernia, is a common cause of groin pain in athletes characterized by concomitant injury to the insertion of the adductor longus and the rectus abdominis muscles. Currently, the literature on CMI is sparse with no standardized physical examination tests used in the diagnosis of this type of injury. Purpose: To determine the diagnostic accuracy of various physical examination tests in the diagnosis of CMI. Study Design: Cohort study (Diagnosis); Level of evidence, 3. Methods: A consecutive series of patients evaluated by the senior author with symptoms consistent with CMI were included. Four physical examination tests were routinely performed in these patients by the senior author and were noted in each patient’s chart as positive or negative: (1) pain with resisted cross-body sit-up in figure-of-4 position, (2) pain with straight-leg sit-up, (3) pain with resisted hip flexion in external rotation (external rotation Stinchfield test), and (4) the presence of an adductor contracture. CMI was independently diagnosed by a reference standard (magnetic resonance imaging [MRI]). All MRI scans were read by a musculoskeletal fellowship-trained radiologist. The sensitivity and specificity of each physical examination test alone and in combination were calculated based on this reference standard. Results: A total of 81 patients were included in this study. MRI was positive for a CMI in 39 patients (48%) overall. Both the cross-body sit-up test and the presence of an adductor contracture were found to have a sensitivity of 100% (specificity, 3% for both). The external rotation Stinchfield test was found to have the highest specificity of 60% (sensitivity, 15%). The sensitivity of all 4 physical examination tests in combination was found to be 100% (specificity, 0%). Conclusion: Certain physical examination maneuvers can be used to assist in the diagnosis of a CMI. The cross-body sit-up test and the presence of an adductor contracture are highly sensitive but nonspecific tests for CMI and therefore should be used in conjunction with diagnostic imaging before deciding on an appropriate treatment course.

Use of Preoperative Magnetic Resonance Imaging to Predict Clinical Outcomes After Core Muscle Injury Repair

“…18 A thorough history and physical examination are the most important aspects in accurately identifying the root cause of an athlete's groin pain and determining the appropriate treatment thereof. In a recently published study, Kurowicki et al 8 performed a set of 4 physical examination tests in patients with suspected CMI, all of whom underwent subsequent CMI repair. The authors calculated the sensitivity and specificity of each of these tests based on a reference standard of MRI.…”

“…In patients with a history and initial physical examination consistent with CMI, 4 additional tests were routinely performed: (1) the cross-body sit-up test, (2) pain with straight-leg sit-up, (3) external rotation Stinchfield test, and (4) the presence of an adductor contracture. 8 Other tests, including the impingement test (flexion, adduction, and internal rotation), were performed to assess for femoroacetabular impingement (FAI). Patients were treated with concomitant CMI repair and arthroscopic labral repair/ femoroplasty under the same anesthetic in patients with a positive impingement test, less than 10 of internal rotation, and labral tears on MRI and radiographs consistent with hip impingement.…”

“…US was considered positive for CMI if hypoechoic areas along the distal rectus insertion and the proximal adductor longus tendon were observed on transverse and linear views, as previously described (Figure 1). 8 In addition, each patient underwent an MRI survey of the pelvis without contrast. The sports hernia MRI protocol at our institution consists of coronal short tau inversion recovery (STIR) and T1 large field-of-view (FOV) (38 cm) sequences and axial T2 fatsaturation, coronal proton density, and sagittal STIR small FOV (24 cm) sequences.…”

“…5,11,20,22,23 History and physical examination, including tests such as the cross-body sit-up test and the presence of an adductor contracture, are important in establishing a diagnosis of CMI. 8 Ultrasound (US) and magnetic resonance imaging (MRI) also serve a role in the diagnosis of a sports hernia. 5,18 The treating surgeon must sometimes make a diagnosis when aspects of the history, physical examination, and imaging do not all coincide with a CMI.…”

“…5,18 The treating surgeon must sometimes make a diagnosis when aspects of the history, physical examination, and imaging do not all coincide with a CMI. 8 Therefore, it is important to continue to research the most critical aspects of the workup in diagnosing a CMI and how these aspects affect patient outcomes. The purpose of this study was to determine if preoperative MRI findings predict clinical outcomes after surgery for CMI.…”