Original articles
Magnetic resonance imaging of the hip: Detection of labral and chondral abnormalities using noncontrast imaging

https://doi.org/10.1016/j.arthro.2004.12.011Get rights and content

Purpose: Traditional imaging techniques have limited ability to detect subtle chondral and labral injuries of the hip. We performed a retrospective review of patients who underwent magnetic resonance imaging (MRI) of the hip and subsequent hip arthroscopy in order to evaluate the ability of optimized, noncontrast MRI to identify tears of the acetabular labrum and defects in articular cartilage. Type of Study: Retrospective review of a consecutive sample. Methods: Between January 1997 and July 2000, 92 patients had MRI of the hip, followed by arthroscopic surgery of that hip by 1 of 2 surgeons (R.B., D.E.P.). Two musculoskeletal MR radiologists blinded to the initial MRI and surgical findings, independently interpreted the studies, looking for the location and degree of articular cartilage and acetabular labral pathology. Results: Of the 92 patients studied, each of 2 radiologists correctly identified 83 (94%) and 84 (95%) of the 88 labral tears present at surgery, respectively. There was 92% interobserver agreement on the MRI studies. For articular cartilage defects on the femoral head and acetabulum, there was good agreement (92% and 86% within 1 grade) between MRI and surgical grading and between the 2 MR readers (kappa of 0.8 for femoral head cartilage and 0.7 for acetabular cartilage). Conclusions: This study shows that noncontrast MRI of the hip, using an optimized protocol, can noninvasively identify labral and chondral pathology. Such information may facilitate deciding which patients warrant surgical intervention, thus preserving hip arthroscopy as a therapeutic tool. Level of evidence: Level II, Development of Diagnostic Criteria Study.

Section snippets

Patient selection

To find patients in whom we could directly compare MRI with arthroscopic results, we reviewed the records of patients who had MRI and subsequent arthroscopy of the hip at our institution from January 1997 to July 2000. These patients were found by cross-referencing an MRI database and the hospital’s radiology report system with the records of 2 surgeons who perform hip arthroscopy at our institution. We excluded patients for whom a comprehensive surgical record, including arthroscopic pictures

Results

The study group comprised 92 patients with 58 women (63%) and 34 men (37%). The mean patient age was 38.5 years (range, 15 to 74 years). There were 56 (61%) right hips and 36 (39%) left hips. The average interval between MRI and arthroscopy was 93 days (range, 1 to 562 days).

Discussion

The acetabular labrum is a fibrocartilaginous ring that surrounds the bony acetabulum and blends inferiorly with the transverse acetabular ligament. It increases the joint surface area by adding depth to the acetabulum, and thereby reduces mechanical stress on the articular cartilage.9, 10

The labrum consists of densely packed collagen bundles that are more loosely organized when compared with the meniscus of the knee.11 Electron microscopy divides the labrum into 3 distinct layers, of which the

Conclusion

In conclusion, MRI offers a noninvasive method to screen patients with symptoms referable to the hip by revealing the presence of focal chondral lesions and labral tears. This preserves hip arthroscopy as a therapeutic, rather than diagnostic, tool.

Acknowledgment

The authors thank Dr. Margaret Peterson for her help in the statistical analysis of the data from this project.

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