Effects of arthroscopic meniscectomy or meniscoplasty of discoid meniscus on lower limb axial alignment: a systematic review and meta-analysis

The purpose of this study was to investigate the effect of meniscectomy and meniscoplasty on the lower limb axial alignment in patients with discoid meniscus (DM). A literature search was conducted in both Chinese and English databases (Chinese search bases: China National Knowledge Infrastructure, Wanfang, and China Science and Technology Journal Database; English search bases: PubMed, Embase, Cochrane Library, Web of Science). In the bilateral experiments, the weighted mean difference (WMD) with a 95% Confidence Interval (CI) was used as the pooled effect size, while the Effect Size (ES) with 95%CI was used for continuous variables in single-group experiments. Totally, 11 papers were included. There was no statistically significant difference in the post-arthroscopic surgery outcomes when comparing DM and non-DM in terms of mechanical axis deviation (MAD), mechanical lateral distal femoral angle (mLDFA), tibiofemoral angle (TFA), lateral knee space, and Lysholm score (all P > 0.05). The mechanical proximal tibia angle (mPTA) improvement after DM surgery was lower than that after non-DM surgery (P < 0.05). No significant differences were found in MAD, mLDFA, TFA, or lateral knee space after various arthroscopic DM surgeries (all P > 0.05). Postoperative lower limb axial alignment and knee function did not significantly differ between DM and non-DM patients, nor did they vary substantially with different surgical approaches for DM. This study suggests that further and more in-depth research is needed to assess the changes in lower limb axial alignment following surgery in patients with DM.