Meniscal Allograft Follow-up

Abstract & Commentary

Synopsis: A short- to intermediate-term follow-up of 23 meniscal transplants. All patients received nonirradiated, cryopreserved allograft menisci (CryoLife) sized based on plain radiographs with correction for magnification. Bone plugs were used to secure the meniscal horns for both medial (11) and lateral (12) grafts. An arthroscopic technique that Stollsteimer and colleagues previously published was used in all cases.

Source: Stollsteimer GT, et al. Meniscal allograft transplantation: A 1- to 5-year follow-up of 22 patients. Arthroscopy 2000;16(4):343-347.

All patients were evaluated clinically at one to five years (average 40 months) postoperatively, and 12 patients underwent magnetic resonance imaging (MRI) scans of both knees. At follow-up, 18 of 23 patients had improvement in pain following the procedure. Lysholm scores improved from an average of 47.2 to 75.6, but IKDC demonstrated normal or nearly normal scores in only 13 of 23 knees. Of most significance, however, was the fact that MRI demonstrated significant shrinkage of the transplanted menisci. The average size of the transplanted meniscus was just 62% (range, 31-100%) of that in the opposite knee.

COMMENT BY MARK MILLER, MD

Although this article suffers from lack of long-term follow-up and did not include MRIs of all knees, it does highlight some important concerns regarding meniscal transplantation. As Stollsteimer and colleagues point out, meniscal transplantation is an extremely challenging (and costly) procedure. Before it is universally accepted, we have an obligation to ensure that it will be successful. Although most patients in this study improved clinically, the success of this operation does not come close to the improvement in scores from anterior cruciate ligament (ACL) reconstruction, for example. Therefore, it is probably best considered a salvage procedure that is perhaps still investigational.

Of most concern in this report is the shrinkage of grafts on MRI evaluation. Several previous anecdotal reports of graft shrinkage are substantiated by this report, and this mandates further study of this important issue. Meniscal shrinkage is, at best, difficult to assess arthroscopically. Stollsteimer et al’s assessment of shrinkage on a volumetric basis with MRI is probably more reasonable. But what does it mean? The question that remains is whether the transplanted meniscus functions like a native meniscus. Perhaps weight-bearing or dynamic MRIs will give us further clues in the future. Longer-term follow-up studies may also give us some idea if transplantation delays the onset of degenerative arthritis in these patients. We should proceed with caution until more is known about the long-term efficacy of meniscal transplantation.

What is the average size of nonirradiated, cryopreserved allograft meniscal transplants (compared to the opposite knee) on one- to five-year follow-up MRIs?

a. 125%

b. 100%

c. 95%

d. 62%