Human meniscus allografts' in vivo size and motion characteristics: magnetic resonance imaging assessment under weightbearing conditions.

BACKGROUND

Although many reports have described clinical outcome of meniscus transplants, their size and motion patterns are not well understood. This study assessed postoperative in vivo size and motion patterns of meniscus transplants under full weightbearing conditions.

HYPOTHESIS

The human meniscus transplant has size and motion characteristics similar to the native menisci.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Eight meniscus transplants in 7 knees were studied 15 to 34 months postoperatively. The knees were scanned in an open magnetic resonance imaging 0.5-T superconducting magnet while standing. Single slice sagittal and coronal images were obtained at 0 degrees , 30 degrees , 60 degrees , and 90 degrees of flexion in the operative and contralateral knees.

RESULTS

The mean height and width of the anterior and posterior horns of the transplants were similar to those of native menisci. The millimeters of coronal displacement of motion of the midbody were also similar between the transplants and the native menisci. The anterior horn of the native medial menisci moved a mean of 5 mm more (total anterior to posterior translation, P < .05) than did the transplants. The posterior horn of the native medial menisci, and both horns of the native lateral menisci, also tended to move more than the corresponding horns of the transplanted menisci, although this result could not be confirmed statistically, given the number of menisci studied.

CONCLUSION

Meniscus transplants had similar size and midbody motion characteristics as the native menisci. The horns of the meniscus transplants tended to show decreased motion compared with the native menisci. The operative techniques and subsequent healing of the graft bone and peripheral attachments provided a stable meniscus construct.