Fig. 1
From: Spondylolisthesis and mismatch deformity affect outcomes after total knee arthroplasty
Meyerding classification explained [30]. A Represents grade 1 spondylolisthesis with anterior translation of L4 on L5 within the “a” range of < 25%. B Represents grade 2 spondylolisthesis with anterior translation at the same level within the “b” range of 25–50%. C Represents grade 3 spondylolisthesis with anterior translation of L5 on S1 within the “c” range of 50–75%. D, E were not involved in this study but represent 75–100% anterior displacement within the “d” range, and spondyloptosis (>100% anterior displacement), respectively. These measurements are with respect to the anterior aspect of the inferior vertebral body. Similarly, the posterior aspect of the superior vertebral body may be used to assess grade as the percentages of listhesis remain consistent