Learning Curve For Lateral Meniscal Allograft Transplantation: Preventing Meniscal Extrusion

Abstract

Purpose: This study analyzes the large number of lateral meniscal allograft transplantation (LMAT) procedures conducted by a single surgeon over 23 years to determine whether the absolute amount of graft subluxation and the incidence of extrusion are different at the present time compared to the early MAT era. Methods: We reviewed 320 cases of LMAT performed by a single surgeon between 1996 and 2019. This cohort was chronologically divided into 8 groups (of 40 subjects). The absolute amount of subluxation was measured by the coronal sections of magnetic resonance images taken 1 year after operation. Subluxation by more than 3 mm was considered as extrusion. The graft extrusion learning curve was plotted in each series using the learning curve cumulative summation test (LC-CUSUM). Results: Extrusion incidence was 41.6%, and the mean absolute amount of graft subluxation was 3.4 +/- 2.2 mm for all subjects. There were significant between-group differences in extrusion incidence and absolute amount of graft subluxation (extrusion incidence, P < .001; absolute amount of graft subluxation, P < .001), and the extension incidence and graft subluxation decreased from Group I (72.5%, 4.6 +/- 1.7) to Group VIII (27.5%, 2.5 +/- 2.1). LC-CUSUM analysis signaled that the surgeon had achieved predefined acceptable outcomes in avoiding extrusion after 128 cases. Conclusion: The incidence of extrusion and absolute amount of graft subluxation decreased significantly over a period of 23 years, and the surgeon achieved a certain level of proficiency after 128 cases. Level of Evidence: Level IV, Case series.