We examined experimentally whether a longitudinal tear in the avascular zon
e of a rabbit meniscus can be healed by meniscal rasping. A full-thickness
longitudinal tear 5-mm long was artificially created in the avascular zone
of the anterior segment of both medial menisci. Meniscal rasping was then d
one on the femoral surface of the right meniscus from the parameniscal syno
vium to the inner segment including the tear. The left meniscus was left wi
thout further treatment as control. Two to 4 weeks after surgery, the hyper
trophic synovium was observed invading from the parameniscal region to the
injured portion. Eight to 16 weeks after surgery, the tear was almost compl
etely healed. In contrast, neither hypertrophy of the synovium covering the
tear nor healing was induced in the control meniscus. The mechanical test
showed that there was a significant difference in the tensile strength and
the stiffness of the injured portion between the rasped meniscus and the co
ntrol meniscus. Meniscal rasping is easy to do, is effective, and causes fe
w adverse effects with menisci. This procedure may be a treatment option fo
r clinical cases of meniscal tear in the avascular zone for which we have n
o effective and clinically applicable methods at present, although further
investigation is needed before clinical application.