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Updated: Jun 11, 2025
Imaging of the Microstructural Failure Mechanism in the Human Hip
Published on: September 29, 2023
Imaging characteristics of hip joint microinstability: a case-control study of hip arthroscopy patients
Renuka M Vesey1, Andrew A MacDonald2, Matthew J Brick3
1Faculty of Medicine and Health Sciences, University of Auckland, Auckland, New Zealand.
Objectives:
Hip microinstability is a clinical entity increasingly recognized and treated but challenging to diagnose with a lack of objective criteria. This study assessed the prevalence and diagnostic accuracy of different imaging findings for hip microinstability on radiograph and MR.
Methods:
A retrospective case-control study of 224 hips treated with arthroscopic surgery by a single orthopedic surgeon, 112 hips with clinical microinstability and 112 controls without. Pre-operative radiograph and MRI/MRA imaging were evaluated by two musculoskeletal radiologists to assess morphological parameters and imaging signs reportedly associated with hip microinstability.
Results:
Four imaging features reached significance as predictors of microinstability via three-step logistic regression: labral hyperplasia and decreased lateral center edge angle on MR (OR 2.45 and 0.93, respectively) and the absence of positive ischial spine sign and absence of osteophytes on radiographs (OR 0.47 and 0.28, respectively). Increased acetabular anteversion and absence of cam lesions were more likely in the microinstability group (p = 0.02 and 0.04, respectively), but not independent predictors. Labral tears, chondral loss, abnormal ligamentum teres, anterior capsule thinning, iliocapsularis to rectus femoris ratio, posterior crescent sign, cliff sign, and femoro-epiphyseal acetabular roof (FEAR) index were not associated with microinstabillity.
Conclusion:
Imaging features may be predictive of hip microinstability in some cases. Decreased LCEA, increased acetabular anteversion, and labral hyperplasia were associated with microinstability in this study, while many other published imaging findings were not. Imaging remains complementary, but not definitive, in the diagnosis of hip microinstability.
Insights
Diagnosing hip microinstability is challenging. This study found that labral hyperplasia and decreased lateral center edge angle on MRI, along with specific radiographic findings, can help predict hip microinstability.
Area of Science:
- Orthopedics
- Radiology
- Sports Medicine
Background:
- Hip microinstability presents diagnostic challenges due to a lack of objective criteria.
- Accurate diagnosis is crucial for effective treatment and patient outcomes.
Purpose of the Study:
- To assess the prevalence and diagnostic accuracy of various imaging findings for hip microinstability.
- To identify reliable imaging predictors of hip microinstability using radiography and MRI.
Main Methods:
- A retrospective case-control study involving 224 hips (112 with microinstability, 112 controls).
- Pre-operative radiographs and MRI/MRA were reviewed by musculoskeletal radiologists for specific morphological parameters and signs.
- Logistic regression analysis was used to identify significant predictors of hip microinstability.
Main Results:
- Labral hyperplasia and decreased lateral center edge angle on MRI, and absence of the ischial spine sign and osteophytes on radiographs were significant predictors.
- Increased acetabular anteversion and absence of cam lesions were more common in the microinstability group but not independent predictors.
- Several other previously reported imaging findings were not associated with hip microinstability.
Conclusions:
- Certain imaging features, including labral hyperplasia and decreased lateral center edge angle, show predictive value for hip microinstability.
- Many previously suggested imaging markers were not found to be significant in this study.
- Imaging is a valuable complementary tool but not definitive for diagnosing hip microinstability.
