Response to 'Comment on: 3-T direct MR arthrography of the wrist: Value of finger trap distraction to assess intrinsic ligament and triangular fibrocartilage complex tears'

Effect of elbow MRI with axial traction on articular cartilage visibility-a feasibility study

OBJECTIVE

Accurate evaluation of the articular cartilage of the elbow using MRI is sometimes challenging because of its anatomical complexity and relatively small size. Moreover, the articular cartilage of the humerus is in close contact with the opposing cartilage surfaces. Magnetic resonance arthrography with traction was reported to resolve this issue; however, less invasive methods are desirable. This study aimed to assess the effect of MRI with axial traction (without arthrography) on joint space widening and cartilage outline visibility of the elbow.

MATERIALS AND METHODS

We enrolled 10 volunteers (female = 1; mean age, 36.7 ± 8.6; range 28-56) and performed MRI with and without axial traction on the elbow. Joint space widths were measured, and the humeral articular cartilage outline visibility was evaluated at the radiocapitellar joint and lateral one-third and medial one-third of the ulnohumeral joints. Measurements were compared using the Wilcoxon signed-rank test. Significance was set at p < 0.05. Volunteers scored pain and discomfort during MRI with traction using the visual analog scale in a questionnaire format.

RESULTS

Traction significantly increased joint space width at the radiocapitellar joint. Humeral articular cartilage outline visibility also significantly improved at the radiocapitellar joint. Pain and discomfort scores during traction MRI were low.

CONCLUSION

MRI of the elbow with traction widens joint space and enables better articular cartilage visibility at the radiocapitellar joint. Anatomical features of the elbow might have affected these results. Therefore, it would be safe and useful for evaluating elbow injuries involving articular cartilage lesions.

Ankle Traction During MRI of Talar Dome Osteochondral Lesions

OBJECTIVE

The objective of our study was to assess the impact of axial traction during MRI of talar dome osteochondral lesions using a small-FOV coil.

SUBJECTS AND METHODS

A prospective study of 33 patients undergoing high-resolution MRI of the ankle using a microscopy coil with and without axial traction was performed. Two radiologists independently measured the tibiotalar joint space width and semiquantitatively graded intraarticular joint fluid dispersion, cartilage surface visibility of the osteochondral lesion, and cartilage surface visibility elsewhere in the tibiotalar joint before and after traction. Patients were instructed to report any discomfort during ankle traction.

RESULTS

None of the patients reported discomfort or other symptoms during ankle traction. The tibiotalar joint space significantly increased (increase in cartilage-cartilage distance, 0.5-0.7 mm; all, p < 0.05) after traction compared with before traction. The degree of intraarticular joint fluid dispersion and the cartilage surface visibility at the osteochondral lesion and elsewhere in the tibiotalar joint improved after traction (all, p < 0.05).

CONCLUSION

Traction MRI of the ankle is safe and technically feasible. This study is the first to date to investigate the effect of ankle traction on the MRI assessment of talar dome osteochondral lesions. Traction improves cartilage surface visibility of talar dome osteochondral lesions.

Elbow MR arthrography with traction

OBJECTIVE

To assess the effect of axial traction during MR arthrography (MRA) of the elbow joint on joint space widening, contrast dispersion between opposing cartilage surfaces and cartilage surface visibility.

METHODS

11 patients with elbow MRA with and without axial traction were prospectively studied. Two radiologists independently measured the elbow joint space width and semi-quantitatively graded contrast material dispersion between the opposing cartilage surfaces as well as the articular cartilage surface visibility before and after traction. The detection and visibility of articular cartilage defects were also compared before and after traction. Patients were instructed to report on pain or any other symptoms during elbow traction.

RESULTS

No patient reported discomfort, pain or any other symptoms related to traction on immediate and intermediate-term follow-up. Joint space width increased, more at the radiocapitellar joint space (Δ = 0.63 mm, p = 0.005) than at the ulnotrochlear joint space (Δ = 0.17 mm, p = 0.012), with contrast dispersion into the radiocapitellar joint and cartilage visibility of the radiocapitellar joint space significantly improving after traction (all p < 0.05). All of these parameters also improved at the ulnotrochlear joint, although this did not reach statistical significance. Traction improved the visibility of cartilage defects.

CONCLUSION

This is the first study to evaluate the effect of traction on MRA of the elbow joint. This technique is safe and technically feasible. Traction MRA improves the cartilage surface visibility and cartilage defect visibility.

ADVANCES IN KNOWLEDGE

This technique is safe and technically feasible. Traction MRA improves cartilage surface visibility and cartilage defect visibility.