Aims Robotic-assisted total knee arthroplasty (RA-TKA) is theoretically more accurate for component positioning than TKA performed with mechanical instruments (M-TKA). Furthermore, the ability to incorporate soft-tissue laxity data into the plan prior to bone resection should reduce variability between the planned polyethylene thickness and the final implanted polyethylene. The purpose of this study was to compare accuracy to plan for component positioning and precision, as demonstrated by deviation from plan for polyethylene insert thickness in measured-resection RA-TKA versus M-TKA. Methods A total of 220 consecutive primary TKAs between May 2016 and November 2018, performed by a single surgeon, were reviewed. Planned coronal plane component alignment and overall limb alignment were all 0° to the mechanical axis; tibial posterior slope was 2°; and polyethylene thickness was 9 mm. For RA-TKA, individual component position was adjusted to assist gap-balancing but planned coronal plane alignment for the femoral and tibial components and overall limb alignment remained 0 ± 3°; planned tibial posterior slope was 1.5°. Mean deviations from plan for each parameter were compared between groups for positioning and size and outliers were assessed. Results In all, 103 M-TKAs and 96 RA-TKAs were included. In RA-TKA versus M-TKA, respectively: mean femoral positioning (0.9° (SD 1.2°) vs 1.7° (SD 1.1°)), mean tibial positioning (0.3° (SD 0.9°) vs 1.3° (SD 1.0°)), mean posterior tibial slope (-0.3° (SD 1.3°) vs 1.7° (SD 1.1°)), and mean mechanical axis limb alignment (1.0° (SD 1.7°) vs 2.7° (SD 1.9°)) all deviated significantly less from the plan (all p < 0.001); significantly fewer knees required a distal femoral recut (10 (10%) vs 22 (22%), p = 0.033); and deviation from planned polyethylene thickness was significantly less (1.4 mm (SD 1.6) vs 2.7 mm (SD 2.2), p < 0.001). Conclusion RA-TKA is significantly more accurate and precise in planning both component positioning and final polyethylene insert thickness. Future studies should investigate whether this increased accuracy and precision has an impact on clinical outcomes. The greater accuracy and reproducibility of RA-TKA may be important as precise new goals for component positioning are developed and can be further individualized to the patient. Cite this article: Bone Joint J 2021;103-B(6 Supple A):74–80.

Purpose: Owing to the nature of orthopaedic surgery, occupational hazards and musculoskeletal pain (MSP) are inherent. These hazards have been well-documented among practicing orthopaedic surgeons, but there remains a paucity of data regarding MSP among orthopaedic surgery residents. The purpose of this study was to identify the prevalence and quantify the extent of work-related MSP among orthopaedic surgical residents. We also sought to analyze resident attitudes, beliefs, and behaviors regarding surgical ergonomics. Methods: An online survey was sent to 78 orthopaedic surgery resident program directors to be distributed to residents within their programs. The survey included three main sections: symptoms by body part, attitudes/beliefs/behaviors regarding surgical ergonomics, and finally demographics. Pain was reported as using the 0 to 10 Numeric Rating Scale, with 0 = no pain and 10 = maximum pain. Several questions about resident well-being were assessed using the Maslach Burnout Inventory. Results: Seventy-six orthopaedic surgery residents completed the survey, 72% men and 28% women. Most residents (97%) experience procedural-related MSP. Average pain scores of all residents was 3.52/10. Notable levels of MSP (≥4/10) were most common in the lower back (35%), neck (29.7%), and feet (25.7%). A positive association exists between higher MSP and lower work satisfaction ( P = 0.005), burnout ( P = 0.04), and callousness toward others ( P < 0.0001). MSP has notable impact on resident behaviors including over-the-counter medication use, stamina, concentration, and degree of irritability. Conclusion: The prevalence of MSP among orthopaedic surgical residents is extremely high. Our study demonstrates that MSP has a notable impact on resident concentration, degree of irritability, and other burnout symptoms. The results of this study highlight the importance of limiting compromising procedural positions, ergonomic optimization, and increasing the awareness of the importance of ergonomics among residents. This could have future implications on productivity and career longevity.

Response to stem cell therapy in heart failure is heterogeneous, warranting a better understanding of outcome predictors. This study assessed left ventricular volume, a surrogate of disease severity, on cell therapy benefit. Small to large infarctions were induced in murine hearts to model moderate, advanced, and end-stage ischemic cardiomyopathy.