Mayfield, Cory K.

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.

Study Design: Retrospective comparative analysis of prospective cohort. Objective: To determine whether sacroiliac (SI) screw fixation ipsilateral to hand dominance compared to bilateral fixation impacts personal hygiene (wiping) after toileting. Methods: Inclusion criteria were adult spinal deformity (ASD) patients with long arthrodesis (≥T12-pelvis) who had undergone primary unilateral or bilateral SI fixation with a minimum of 2-years-follow-up. Results: 117 consecutive patients were included and separated into 2 groups: bilateral SI fixation (BL, n = 61) and unilateral SI fixation (UNI, n = 56), with no difference in age. Of UNI patients, 10.7% (6) performed personal hygiene with a different hand after surgery, compared to 6.6% (4) of patients who received BL fixation ( P = 0.422). All UNI patients who switched hands were right-hand dominant, and 5/6 received right-sided fixation. There was no statistical difference found between number of levels fused (<8, 9-11, or >11 levels) and changes in personal hygiene habits. Over a third of patients from both groups had difficulty performing personal hygiene after fusion (UNI = 39.3% BL = 36.1%, P = 0.719). Conclusion: SI screws increase the difficulty of performing personal hygiene; yet, the side of unilateral screws does not significantly change personal hygiene habits when compared to bilateral screw placement. Moreover, the length of the construct does not have a significant impact on ability to perform personal hygiene, cause changes in habits, or require the assistance of another individual. However, among our sample of individuals, bilateral fixation did result in a higher rate of revision instrumentation.

Case: An 65-year-old immunocompetent female developed a Leclercia adecarboxylata infection following the repair of closed olecranon fracture. L. adecarboxylata is associated with polymicrobial infections, infections in immunocompromised patients and penetrating or open wounds. Following speciation, intravenous ceftriaxone was started. Two weeks later, the patient presented with leukopenia and neutropenia. Per infectious disease recommendations, the patient was switched to intravenous ertapenem with resolution of both infection and neutropenia. The olecranon fracture went on to heal fully. Conclusions: This case describes a rare postoperative monomicrobial infection with L. adecarboxylata in an immunocompetent host following musculoskeletal trauma and identifies L. adecarboxylata as a potential emerging hospital-acquired pathogen following orthopedic surgery.