Purpose Robotic-assisted total knee arthroplasty (RA-TKA) was introduced to improve limb alignment, component positioning, soft-tissue balance and to minimize surgical outliers. This study investigates perioperative outcomes, complications, and early patient-reported outcome measures (PROMs) of one imageless RA-TKA system compared to conventional method TKA (CM-TKA) at 24-month follow-up. Methods This multi-surgeon retrospective cohort analysis compared 111 imageless RA-TKA patients to 110 CM-TKA patients (n = 221). Basic demographic information, intraoperative and postoperative data, and PROMs, including the functional score of the Knee Society Score (KSS-FS), The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the Short Form 12 Mental and Physical scores (SF-12M and P), were collected and recorded preoperatively, at 3-, 12-and 24-months postoperatively. Range of motion (ROM), estimated blood loss (EBL), surgical duration, and complications were also collected. Results There were no baseline patient demographic diferences between groups. EBL (240 vs. 190 mL, p < 0.001) and surgical duration (123 vs. 107 min, p < 0.001) were signiicantly greater in RA-TKA. There were no signiicant diferences in postoperative complications, ROM, length of stay (LOS), and PROMs between cohorts at 3-, 12-, 24-months postoperatively. Conclusions Imageless RA-TKA is associated with greater EBL and surgical duration compared to CM-TKA. However, at 24-month follow-up, there were no signiicant diferences in ROM, LOS, complications and PROMs between cohorts. Imageless robotic surgery leads to similar 24-month clinical outcomes as compared to CM-TKA. Level of evidence IIIKeywords Total knee arthroplasty • Robotic-assisted total knee arthroplasty • Imageless robotic TKA • Patient-reported outcome measures • Complications

Study design: Retrospective cohort study. Objective: Respiratory compromise (RC) is a rare but catastrophic complication of anterior cervical spine surgery (ACSS) commonly due to compressive fluid collections or generalized soft tissue swelling in the cervical spine. Established risk factors include operative duration, size of surgical exposure, myelopathy, among others. The purpose of this current study is to identify the incidence and clinical course of patients who develop RC, and identify independent predictors of RC in patients undergoing ACSS for cervical spondylosis. Methods: A large, prospectively-collected registry was used to identify patients undergoing ACSS for spondylosis. Patients with posterior cervical procedures were excluded. Baseline patient characteristics were compared using bivariate analysis, and multivariate analysis was employed to compare postoperative complications and identify independent predictors of RC. Results: 298 of 52,270 patients developed RC (incidence 0.57%). Patients who developed RC had high rates of 30-day mortality (11.7%) and morbidity (75.8%), with unplanned reoperation and pneumonia the most common. The most common reason for reoperations were hematoma evacuation and tracheostomy. Independent patient-specific factors predictive of RC included increasing patient age, male gender, comorbidities such as chronic cardiac and respiratory disease, preoperative myelopathy, prolonged operative duration, and 2-level ACCFs. Conclusion: This is among the largest cohorts of patients to develop RC after ACSS identified to-date and validates a range of independent predictors, many previously only described in case reports. These results are useful for taking preventive measures, identifying high risk patients for preoperative risk stratification, and for surgical co-management discussions with the anesthesiology team.

Background: Robot-assisted surgery was developed to improve accuracy and outcomes in total knee arthroplasty (TKA). One important determinant of TKA success is a well-balanced knee throughout the range of motion. The purpose of this study is to determine if robot-assisted TKA (RA-TKA) results in improved intracompartmental ligament balance compared with conventional jig-based instrumentation (CM-TKA). Methods: This retrospective cohort study included 2 cohortsda CM-TKA (n ¼ 49) vs RA-TKA (n ¼ 37) cohort. Demographic and intraoperative data, including intraoperative compartment loads, were measured after final implant implantation in extension (10 ), mid-flexion (45 ), and full flexion (90 ), using an intraoperative compartment pressure sensor. An a priori power analysis revealed our study exhibited >80% power in detecting a 5-pound (lb) difference in compartment loads in the 2 cohorts. Results: There was no difference between medial and lateral compartment loads in extension, midflexion, and full flexion for the conventional (15.1 lbs, 15.9 lbs, and 13.4 lbs, respectively) vs RA-TKA (14.2 lbs, 15.1 lbs, and 10.3 lbs, respectively). The percentage of patients with high load compartment pressure in flexion (>40 lbs) by the conclusion of the surgery was significantly greater for the conventional (18%) vs the robotic TKA cohort (3%, P ¼ .025). The percentage of patients with unbalanced knees (>20 lbs differential between medial and lateral compartments) in flexion was significantly greater in the conventional (24%) vs robotic TKA cohort (5%, P ¼ .018). Conclusions: In this series, RA-TKA resulted in improved intraoperative compartment balancing in flexion with no observed difference in mid-flexion and extension compared with CM-TKA.