Utility of Four-Dimensional Analysis of the Acetabular Labrum Applying Motion-Gated Multislice Computed Tomography

To analyze the kinesis and morphology of the acetabular labrum (AL) noninvasively, we applied 4-dimensional arthrography with motion-gated multislice computed tomography and compared the results with arthroscopy and Harris hip score (HHS) in 49 symptomatic patients who performed reciprocating hip flexion-extension as we carried out mimic retrospective electrocardiogram-gating acquisition. The kinematics and morphology of AL were classified as stabilized, irregular, or eccentric motion patterns. Of the 9 subjects who had intact or frayed AL on arthroscopy, 7 had stabilized motion (average 50 HHS) and 2 had irregular (44 HHS) motion by CT arthroscopy. Of the 16 without adhesive AL on arthroscopy, 6 had irregular motion (48 HHS) and 4 had eccentric motion (58 HHS). We found that the 4-dimensional arthrography with motion-gated multislice computed tomography can reveal both kinetic and morphological changes of the AL, and facilitate further stratification in subjects with the American Academy of Orthopaedic Surgeons class 0, or 1 or without "detached" morphological findings by arthroscopy.