Multivariate Analysis of Risk Factors of Graft Extrusion After Lateral Meniscus Allograft Transplantation.

PURPOSE: To identify risk factors that predict major graft extrusion (>3 mm in relation to the margin of the tibial plateau) on magnetic resonance imaging (MRI) after lateral meniscus allograft transplantation (MAT) using multivariate logistic regression.

METHODS

In this retrospective trial, inclusion criteria were consecutive lateral MATs from January 2004 to June 2013. Exclusion criteria were the lack of postoperative MRI, loss to follow-up for minimum 2 years, and simultaneous surgery of the articular cartilage or anterior cruciate ligament. According to the measured extent of graft extrusion in postoperative MRI, the lateral MATs were sorted into minor extrusion and major extrusion groups. Multivariate logistic regression was used to analyze risk factors including age, gender, body mass index, time from previous meniscectomy to MAT, extent of previous meniscectomy, previous anterior cruciate ligament reconstruction, knee alignment angle, Kellgren-Lawrence grade, lateral peripheral osteophyte, Outerbridge grade, posterior repair technique the position of bony bridge, and axial plane trough angle.

RESULTS

Enrolled 72 lateral MATs were sorted into minor extrusion (n = 34) and major extrusion groups (n = 38). As time from previous meniscectomy to lateral MAT increased, the risk of the major graft extrusion after lateral MAT increased (adjusted odds ratio: 1.554, 95% confidence interval: 1.089 to 2.218). Increased axial plane trough angle was also a significant risk factor (adjusted odds ratio: 8.449, 95% confidence interval: 1.710 to 42.250). The other parameters were not significant risk factors.

CONCLUSIONS

Most meniscal grafts after lateral MATs showed major graft extrusion. Significant risk factors for the major graft extrusion included delayed time from previous meniscectomy to MAT and increased axial plane trough angle.

LEVEL OF EVIDENCE: Level III, retrospective comparative study.