Comparison between dedicated MRI and symphyseal fluoroscopic guided contrast agent injection in the diagnosis of cleft sign in athletic groin pain and association with pelvic ring instability

OBJECTIVE

To compare dedicated MRI with targeted fluoroscopic guided symphyseal contrast agent injection regarding the assessment of symphyseal cleft signs in men with athletic groin pain and assessment of radiographic pelvic ring instability.

METHODS

Sixty-six athletic men were prospectively included after an initial clinical examination by an experienced surgeon using a standardized procedure. Diagnostic fluoroscopic symphyseal injection of a contrast agent was performed. Additionally, standing single-leg stance radiography and dedicated 3-Tesla MRI protocol were employed. The presence of cleft injuries (superior, secondary, combined, atypical) and osteitis pubis was recorded.

RESULTS

Symphyseal bone marrow edema (BME) was present in 50 patients, bilaterally in 41 patients and in 28 with an asymmetrical distribution. Comparison of MRI and symphysography was as followed: no clefts: 14 cases (MRI) vs. 24 cases (symphysography), isolated superior cleft sign: 13 vs. 10, isolated secondary cleft sign: 15 vs. 21 cases and combined injuries: 18 vs. 11 cases. In 7 cases a combined cleft sign was observed in MRI but only an isolated secondary cleft sign was visible in symphysography. Anterior pelvic ring instability was observed in 25 patients and was linked to a cleft sign in 23 cases (7 superior cleft sign, 8 secondary cleft signs, 6 combined clefts, 2 atypical cleft injuries). Additional BME could be diagnosed in 18 of those 23.

CONCLUSION

Dedicated 3-Tesla MRI outmatches symphysography for purely diagnostic purposes of cleft injuries. Microtearing at the prepubic aponeurotic complex and the presence of BME is a prerequisite for the development of anterior pelvic ring instability.

CLINICAL RELEVANCE STATEMENT

For diagnostic of symphyseal cleft injuries dedicated 3-T MRI protocols outmatch fluoroscopic symphysography. Prior specific clinical examination is highly beneficial and additional flamingo view x-rays are recommended for assessment of pelvic ring instability in these patients.

KEY POINTS

• Assessment of symphyseal cleft injuries is more accurate by use of dedicated MRI as compared to fluoroscopic symphysography. • Additional fluoroscopy may be important for therapeutic injections. • The presence of cleft injury might be a prerequisite for the development of pelvic ring instability.

[Groin pain in athletes-sportsmen's groin]

CLINICAL/METHODICAL ISSUE

Groin pain in athletes can have various causes. Radiologically, osteitis pubis and clefts with affection of the interpubic disc as well as muscle and tendon tears near the pubic bone can be clearly identified.

STANDARD RADIOLOGICAL METHODS

Magnetic resonance imaging (MRI) is the imaging modality of choice, as well as single-leg stand imaging (flamingo view radiographs), and where appropriate symphysography.

METHODICAL INNOVATIONS

Optimized MRI sequence protocol with oblique (axial oblique) slices parallel to the linea arcuata of the iliac bone is recommended. High-resolution MRI sequences and symphysography can detect superior and secondary cleft formation. Instabilities of the pubic symphysis can be diagnosed using flamingo view radiographs.

PERFORMANCE

The MRI findings of osteitis pubis and clinical symptoms correlate. The presence of parasymphyseal bone marrow edema is the earliest morphological sign of acute osteitis pubis on MR imaging. Edema in the periosteal tissue and isolated muscle lesions next to the symphysis are generally associated with more severe clinical symptoms.

ACHIEVEMENTS AND PRACTICAL RECOMMENDATIONS

Close communication between radiologists and the referring physicians is indispensable when planning an adequate imaging protocol, and precise knowledge of the clinical symptoms in the case of clinical suspicion of osteitis pubis allows for a reliable diagnosis and provides important prognostic information.

Novel pathomorphologic classification of capsulo-articular lesions of the pubic symphysis in athletes to predict treatment and outcome

INTRODUCTION

Radiographic abnormalities of the symphysis as well as the formation of accessory clefts, indicating injury at the rectus-adductor aponeurosis, reportedly relate to longstanding groin pain in athletes. However, yet, no systematic classification for clinical and scientific purposes exists. We aimed to (1) create a radiographic classification based on symphysography; (2) test intra- and interobserver reliability; (3) characterise clinical significance of the morphologic patterns by evaluating success of injection therapy.

PATIENTS AND METHODS

We retrospectively reviewed symphysography, AP radiographs, and MRI of the pelvis from 70 consecutive competitive athletes, with chronic groin pain. Symphysographs were evaluated for intra- and interobserver variance using cohen's kappa statistics. Morphologic studies of the different contrast distribution patterns and their clinical and radiological correlation with symptom relief were investigated. All patients were followed up to evaluate immediate and long-term response to the initial therapeutic injection with steroid.

RESULTS

Four reproducible symphysographic patterns were identified: type 0, no changes; type 1, symphyseal disk degeneration; types 2a with unilateral clefts, bilateral clefts (2b), suprapubic clefts (2c); and type 3, with expanded or multidirectional clefts. Analysis revealed excellent intra (0.94)-and interobserver (0.90) reliability. Our findings showed that 78.6% of our patients had significant short-term improvement enabling early resumption of physiotherapy, only in types 1 and 2 (p = 0.001), while type 0 and 3 did not respond. At follow-up, only 21.8% had permanent pain relief. Regarding the detection of pathologic clefts with symphysography, sensitivity (88%) and specifity (77%) were superior to that of MRI.

CONCLUSIONS

A reproducible symphysography-based classification of distinct morphologic patterns is proposed. It serves as a predictive tool for response to injection therapy in a select group of pathologic lesions. Complete recovery after injection can only be expected in a lesser percentage, as this might indicate surgical treatment for long-term non-responders.