No Difference in Range of Motion, Components, or Complications Following Conversion of Robotic-Assisted Total Knee Arthroplasty Compared to Manual TKA After Undergoing Manual or Robotic-Assisted Unicompartmental Knee Arthroplasty.

Background: Conversion surgery from unicondylar knee arthroplasty (UKA) to total knee arthroplasty (TKA) remains a challenge due to scarring, implant/cement removal, and loss of bony landmarks. Robotic-assisted (RA) TKA may assist in challenges seen in manual conversion TKA. The aim of this study is to identify if there are differences in components and functional outcomes dependent on manual/RA primary UKA and conversion TKA. Methods: A retrospective chart review was performed on patients undergoing conversion from UKA to TKA over a 10-year period at a single institution. Data extracted included surgical technique, reason for UKA failure, range of motion at 1 year, need for augments, and utilization of revision components. Results: Forty-nine patients (50 knees) with a UKA converted to a TKA were divided into 4 groups based on primary and conversion surgery: manual-to-manual (n = 11), manual-to-robot (n = 11), robot-to-manual (n = 11), and robot-to-robot (n = 17). There was no difference in need for augments (P = .376), size of poly (P = .23), postoperative flexion (P = .52), or extension (P = .76) at 1 year between the 4 groups. However, patients with primary manual UKA did require significantly more augments during revision (P = .032). Conclusions: Our study did not show any statistically significant differences of primary RA or manual UKA to RA or manual TKA in terms of range of motion at 1 year, complications, or differences in components. RA conversion from UKA to TKA is a new but equivalent technique to manual conversion. Primary surgery may impact the requirement for augments during conversion surgery.

Utilization of a Revision Acetabular Shell as a Tibial Cone in a Revision Total Knee Arthroplasty Setting.

One of the biggest challenges of a revision total knee arthroplasty is how to obtain adequate tibial metaphyseal fixation in the setting of significant bone loss. There are multiple implants, including stems, metaphyseal cones, and metaphyseal sleeves, that help provide increased fixation and stability. This report demonstrates a case in which a porous tantalum metal revision acetabular shell was used as a large tibial cone, as none of the above options were viable due to the size and position of the tibial defect.