Malalignment and malposition of quadriceps-sparing approach in primary total knee arthroplasty: a systematic review and meta-analysis

BACKGROUND Quadriceps-sparing (QS) approach is considered to be the most minimally invasive surgery for total knee arthroplasty (TKA). We perform this meta-analysis to evaluate whether malalignment and malposition are more biased towards the QS approach compared to the traditional medial parapatellar (MP) approach, which is still controversial. METHODS According to the PRISMA guidelines, a comprehensive search was conducted in the databases of PubMed, the Cochrane library, and Embase. Relevant measures were extracted independently by two investigators. RESULTS Five randomized controlled trials (RCTs) and eight retrospective studies including a total of 1261 cases were identified. The QS approach was associated with more outliers of hip-knee-ankle (HKA) angle (p = 0.03), coronal tibial component angle (p = 0.03), and femoral notch (p = 0.05). However, the differences of the outlier of the coronal femoral component angle between the two groups were not statistically significant. CONCLUSIONS This meta-analysis indicates that the QS approach is related to the high risk of malalignment and malposition. However, different studies reported different indicators resulting in small samples for analyzing the radiological outcomes. In addition, both of the relatively long learning curve and the present instruments might increase the risk of malalignment and malposition of the QS approach, which needs further study and improvement.