The effects of graft shrinkage and extrusion on early clinical outcomes after meniscal allograft transplantation

Abstract

BackgroundGraft shrinkage or radial extrusion is a reported complication after meniscus allograft transplantation (MAT). Whether shrinkage or extrusion progress after surgery and whether they are associated with the clinical outcome of MAT remain debatable. In this study, graft shrinkage and extrusion were measured in the coronal and sagittal planes using serial postoperative magnetic resonance imaging (MRI). The purpose of this study was to evaluate if graft shrinkage or extrusion is correlated to the clinical outcome of MAT.MethodsMRIs acquired at 3 and 12 months postoperatively in 30 patients (21 men and 9 women) who underwent MAT (6 medial and 24 lateral menisci) from 2010 to 2016 were analyzed. Two orthopedic surgeons and two musculoskeletal specialized radiologists each performed the MRI measurements. Allograft shrinkage was measured by the width and thickness of the graft at the coronal and sagittal planes. To determine the graft extrusion, distances between the proximal tibia cartilage margin and the extruded graft margin were measured in both coronal (either lateral or medial) and sagittal (both anterior and posterior) plane and relative percentage of extrusion (RPE) were calculated. Subjective International Knee Documentation Committee (IKDC) scores at 12 months were evaluated as a clinical outcome measurement, and correlations between shrinkage or extrusion of allograft and IKDC score were analyzed.ResultsIn the coronal plane, radial RPE averaged 43.6% at postoperative 3 months, but there was no significant progression of extrusion at 12 months (average 42.0%) (P = 0.728). In the sagittal plane, there were no significant progressions of anterior and posterior RPE (P = 0.487 and 0.166, respectively) between postoperative 3 and 12 months. Shrinkage was calculated by multiplying the width and height of the three sections and summing these values. There was no significant progression of shrinkage between postoperative 3 and 12 months (P = 0.150). RPE in the radial (R = 0.147, P = 0.525), anterior (R = 0.249, P = 0.264), and posterior (R = 0.230, P = 0.315) directions and shrinkage (R = 0.176, P = 0.435) were not correlated to IKDC score at postoperative 12 months.ConclusionsIn the coronal and sagittal planes, extrusion and shrinkage did not progress from 3 months to 1 year. Extrusion and shrinkage had no correlation with early clinical outcomes. This finding suggests that graft extrusion or shrinkage may be not a great concern especially in early postoperative period of MAT, and multiple, serial MRI may be not necessary.

High body mass index is a risk factor for unfavorable clinical outcomes after medial meniscus posterior root repair in well-aligned knees

“…Extrusion did not correlate with the clinical outcomes when the follow-up time was short [28]. However, at the 5-year follow-up, reduced meniscus extrusion may lead to more favorable midterm outcomes after pullout fixation for MMPRTs [29].…”

Correlation analysis of potential factors influencing graft maturity based on MRI after lateral meniscal allograft transplantation

“…The study by Lee et al 8 showed a similar conclusion for shrinkage of the WPH and WMB, but no data for the WAH were available in his study. However, in the study by Kim et al 22 , no significant progression of shrinkage was observed between 3 and 12 months postoperatively. The reason for this effect might be that in Kim's study, shrinkage was calculated by multiplying the width and height of the three sections and adding these values together.…”

“…In our study, CGE and the CPRE increased with time but became steady after 2 years postoperatively; however, changes in the ACMD, APRE, PCMD and PCRE were more complicated but varied in a contrary manner, indicating that the sagittal locations of allografts were constantly changing. A study by Kim et al 22 showed that in the sagittal plane, the mean absolute ACMDs were 2.59 ± 1.75, 2.58 ± 1.85, and 2.37 ± 1.60 mm, and the mean relative ACMDs were 20.7% ± 13.1%, 20.6% ± 13.8%, and 19.0% ± 12.2% at the 3 follow-up time points. The mean absolute PCMDs were − 1.23 ± 3.34, − 1.28 ± 3.08, and − 1.42 ± 2.77 mm, and the mean relative PCMDs were − 10.3% ± 25.9%, − 11.0% ± 24.6%, and − 12.2% ± 23.2% at the same time points.…”

Editorial Commentary: Long-Term Outcomes of Fresh-Frozen Meniscal Allografts—Shrinkage Progresses, but Is It Clinically Significant?

“…[2][3][4] This study, along with previously published long-term data, supports a lack of correlation between the degree of shrinkage and outcomes. 1,5,6 Conversely, it has been reported that there is a narrow anatomic window to place transplants anatomically without significantly altering the pressure distribution across the meniscus. 7 Nonanatomic placement of meniscal allografts has also been shown as a significant predictor for graft extrusion after lateral MAT.…”