Robotic TKA allows for quantifiable precision performing bone resections for implant realignment within acceptable final component and limb alignments. One of the early steps in this robotic technique is after initial exposure and removal of medial and lateral osteophytes, a “pose-capture” is performed with varus and valgus stress applied to the knee in near full extension and 90° of flexion to assess gaps. Component alignment adjustments can be made on the preoperative plan to balance the gaps. At this point in the procedure any posterior osteophytes will still be present, which could after removal change the flexion and extension gaps by 1–3mm. This must be taken into consideration, or changes in component alignment could result in over-correction of gaps can occur. The purpose of this study was to identify what effect the posterior osteophyte's size and location and their removal had on gap measurements between pose-capture and after bone cuts are made and gaps assessed during implant trialing.Introduction
Objective
In total knee arthroplasty (TKA), component realignment with bone-based surgical correction (BBSC) can provide soft tissue balance and avoid the unpredictability of soft tissue releases (STR) and potential for more post-operative pain. Robotic-assisted TKA enhances the ability to accurately control bone resection and implant position. The purpose of this study was to identify preoperative and intraoperative predictors for soft tissue release where maximum use of component realignment was desired. This was a retrospective, single center study comparing 125 robotic-assisted TKAs quantitatively balanced using load-sensing tibial trial components with BBSC and/or STR. A surgical algorithm favoring BBSC with a desired final mechanical alignment of between 3° varus and 2° valgus was utilized. Component realignment adjustments were made during preoperative planning, after varus/valgus stress gaps were assessed after removal of medial and lateral osteophytes (pose capture), and after trialing. STR was performed when a BBSC would not result in knee balance within acceptable alignment parameters. The predictability for STR was assessed at four steps of the procedure: Preoperatively with radiographic analysis, and after assessing static alignment after medial and lateral osteophyte removal, pose capture, and trialing. Cutoff values predictive of release were obtained using receiver operative curve analysis.Introduction
Methods
