Computed tomography arthrography with traction in the human hip for three-dimensional reconstruction of cartilage and the acetabular labrum

• Published in: Clinical radiology 2014-10, Vol.69 (10), p.e381-e391
• Main Authors: Henak, C.R, Abraham, C.L, Peters, C.L, Sanders, R.K, Weiss, J.A, Anderson, A.E
• Format: Article
• Language: English
• Subjects: Acetabulum - diagnostic imaging; Adolescent; Adult; Analysis of Variance; Arthrography - methods; Cartilage, Articular - diagnostic imaging; Contrast Media; Female; Hip Dislocation - diagnostic imaging; Hip Dislocation - surgery; Hip Joint - abnormalities; Hip Joint - diagnostic imaging; Humans; Imaging, Three-Dimensional - methods; Male; Radiology; Reproducibility of Results; Splints; Tomography, X-Ray Computed - methods; Traction - methods; Young Adult
• ISSN: 0009-9260; 1365-229X
• DOI: 10.1016/j.crad.2014.06.009

Aim To develop and demonstrate the efficacy of a computed tomography arthrography (CTA) protocol for the hip that enables accurate three-dimensional reconstructions of cartilage and excellent visualization of the acetabular labrum. Materials and methods Ninety-three subjects were imaged (104 scans); 68 subjects with abnormal anatomy, 11 patients after periacetabular osteotomy surgery, and 25 subjects with normal anatomy. Fifteen to 25 ml of contrast agent diluted with lidocaine was injected using a lateral oblique approach. A Hare traction splint applied traction during CT. The association between traction force and intra-articular joint space was assessed qualitatively under fluoroscopy. Cartilage geometry was reconstructed from the CTA images for 30 subjects; the maximum joint space under traction was measured. Results Using the Hare traction splint, the intra-articular space and boundaries of cartilage could be clearly delineated throughout the joint; the acetabular labrum was also visible. Dysplastic hips required less traction (∼5 kg) than normal and retroverted hips required (>10 kg) to separate the cartilage. An increase in traction force produced a corresponding widening of the intra-articular joint space. Under traction, the maximum width of the intra-articular joint space during CT ranged from 0.98–6.7 mm (2.46 ± 1.16 mm). Conclusions When applied to subjects with normal and abnormal hip anatomy, the CTA protocol presented yields clear delineation of the cartilage and the acetabular labrum. Use of a Hare traction splint provides a simple, cost-effective method to widen the intra-articular joint space during CT, and provides flexibility to vary the traction as required.