Background

Meniscal allograft transplantation (MAT) is a viable treatment option to improve clinical outcomes in patients with postmeniscectomy syndrome. Good long-term clinical outcomes can be impaired by early surgical graft failures. Causes of early surgical graft failure warrant further investigation.

Purpose

To determine the prevalence, types, and distribution pattern of symptomatic arthroscopically confirmed meniscal allograft tears and the associated impact on surgical meniscal allograft survival. It was hypothesized that symptomatic meniscal allograft tears are a common finding and are associated with early surgical meniscal allograft failure.

Methods

This single-center retrospective study included patients undergoing MAT with a minimum follow-up of 2 years. Medial and lateral isolated or combined MAT was performed using the suture-only or bone block fixation technique. Based on a chart review, patient demographics and surgical data were collected. Arthroscopically confirmed meniscal allograft tears were classified according to the type and location of the tear. Surgical meniscal allograft failure was defined if one of the following criteria was met: subtotal/total meniscal allograft resection, meniscal allograft repair, revision MAT, conversion to arthroplasty. Meniscal allograft tears that were left in situ or required resection < 1/3 of the meniscal allograft width were not considered as surgical failures. Group comparisons were performed using the Chi-square test or Fisher’s exact test (categorical variables) and the unpaired t test or Mann-Whitney U test (continuous variables). A survival analysis according to the Kaplan-Meier method was performed (endpoint: surgical meniscal allograft failure) to assess the impact of meniscal allograft tears on graft survival.

Results

A total of 142 patients (54% male; mean age, 29.6 ± 10.4 years) were included in this study after a mean follow-up of 10.3 ± 7.5 years. Meniscal allograft tears were observed in 46 patients (prevalence, 32%) after a median time of 1.2 years following MAT. Meniscal allograft tears affected the following meniscal zones: posterior horns (39%), posterior roots (33%), midbodies (30%), anterior horns (22%) and anterior roots (11%). The following meniscal allograft tear types were observed: root (43%), longitudinal (13%), horizontal (13%), radial (11%), complex (9%), bucket handle (9%), and meniscocapsular separation (2%) tears. No difference in the location and type of meniscal allograft tears was observed between medial and lateral MAT. Meniscal allograft tear types showed a statistically significant association with fixation technique (p < 0.05), with root tears predominant after suture-only (57%) compared to bone block fixation (22%). Patients with meniscal allograft root tears were found to be an average of 5.4 years (95%-CI [1.6,9.2], p < 0.05) younger than patients without root tears. One-year surgical meniscal allograft survival was statistically significantly lower for patients with than without meniscal allograft tears (75% vs. 99%, p < 0.001).

Conclusion

Surgeons should be aware of the high prevalence (32%) of symptomatic meniscal allograft tears. Meniscal allograft tears involving the roots (43%) were predominant, especially in younger patients and after suture-only fixation. Bone block fixation may be considered in young patients undergoing MAT to avoid early surgical graft failure.