Abstract
Introduction
The purpose of this study was to compare the radiographic outcomes of manual versus robotic-assisted medial unicompartmental knee arthroplasty (UKA).
Materials & Methods
Postoperative radiographic outcomes from 86 consecutive robotic-assisted UKAs (RAUKA group) from a single academic center were retrospectively reviewed and compared to 253 manual UKAs (MUKA group) drawn from a prior study at our institution. Femoral coronal and sagittal angles (FCA, FSA), tibial coronal and sagittal angles (TCA, TSA), and implant overhang were radiographically measured to identify outliers. Clinical results at 4–6 weeks postoperative were compared to a control cohort of total knee arthroplasty (TKA) patients from our institution.
Results
When assessing the accuracy of RAUKAs, 91.6% of all alignment measurements and 99.2% of all overhang measurements were within the target range. All alignment and overhang targets were simultaneously met in 68.6% of RAUKAs. When comparing radiographic outcomes between the RAUKA and MUKA groups, statistically significant differences were identified for combined outliers in FCA (2.3% vs. 12.6%, p=0.006), FSA (17.4% vs. 50.2%, p<0.001), TCA (5.8% vs. 41.5%, p<0.001), and TSA (8.1% vs. 18.6%, p=0.023), as well as anterior (0.0% vs. 4.7%, p=0.042), posterior (1.2% vs. 13.4%, p=0.001), and medial (1.2% vs. 14.2%, p<0.001) overhang outliers. RAUKA demonstrated statistically significant improvements in pain and outcomes compared to TKA at 4–6 weeks (p<0.05).
Conclusions
Robotic navigation decreases alignment and overhang outliers compared to manual UKA and improves clinical results compare to TKA in the early postoperative period. Given the association between component placement errors and revision in UKA, this strong significant improvement in accuracy is likely to improve implant survival.
