Restricted kinematic alignment achieves similar relative lateral laxity and greater joint line obliquity compared to gap balancing TKA.

PURPOSE: The purpose of this study was to compare ligament balance and laxity profiles achieved throughout flexion in restricted kinematic alignment (rKA) and gap balancing (GB). rKA and GB both aim to improve soft tissue balance and reduce ligament releases in total knee arthroplasty (TKA). METHODS: One surgeon performed 68 rKA, another performed 73 GB TKAs using the same CR implant and robotic system. rKA limited femoral valgus and tibial varus to 6°, with tibial recuts performed to achieve balance. GB limited tibial varus and femoral valgus to 2°, with femoral resections adjusted to achieve mediolateral balance throughout flexion using predictive-gap planning software. Final joint laxity was measured using a robotic ligament tensioner. Statistical analyses were performed to compare differences in mediolateral balance and joint laxity throughout flexion. Further analyses compared alignment, joint line elevation and orientation (JLO), and frequency of ligament releases and bone recuts. RESULTS: Both techniques reported greater lateral laxity throughout flexion, with GB reporting improved mediolateral balance from 10° to 45° flexion. GB resected 1.7 mm more distal femur (p ≤ 0.001) and had greater overall laxity than rKA throughout flexion (p ≤ 0.01). rKA increased JLO by 2.5° and 3° on the femur and tibia (p ≤ 0.001). Pre-operative and post-operative coronal alignment were similar across both techniques. rKA had a higher tibial recut rate: 26.5% vs 1.4%, p < 0.001. CONCLUSIONS: rKA and GB both report lateral laxity but with different JLO and elevation. Use of a predictive-gap GB workflow resulted in greater mediolateral gap symmetry with fewer recuts. LEVEL OF EVIDENCE: III, retrospective cohort study.

Initial Experience with the NAVIO Robotic-Assisted Total Knee Replacement-Coronal Alignment Accuracy and the Learning Curve.

One of the primary aim of total knee arthroplasty (TKA) is restoration of the mechanical axis of the lower limb. Maintenance of the mechanical axis within 3 degrees of neutral has been shown to result in improved clinical results and implant longevity. The aim of this study was to investigate the efficacy of this robotic-assisted system in coronal plane component positioning in TKA. We also describe the learning curve associated with adoption of this technology. A total of 72 total knee replacements were completed between November 2017 and September 2018 by a single surgeon using the robotic-assisted surgery (RAS) system. Cases were recorded from the time the study surgeon first adopted this technology and represent the "learning curve." Pre- and postoperative coronal weight-bearing alignments were measured and intraoperative robotic-assisted registration data and duration of use were collected. Of the 72 TKAs in this series, 93.3% were corrected to the desired alignment of within 3 degrees of neutral. The knees that were not corrected to neutral had a mean preoperative alignment of 11.57 degrees of deformity as compared with 4.29 degrees for those that were corrected to neutral. A learning curve effect during adoption of this new technology was not found when analyzing RAS usage time. The RAS system produced accurate coronal alignment in TKA in more than 93% of cases with no learning curve effect. Our study suggests that this system is easily adopted, safe, and accurate.

Extension Casting For Both-Bone Forearm Fractures In Children.

Paediatric forearm fractures are commonly treated with closed reduction and cast immobilization. Determining the best way to cast these fractures during the initial presentation may prevent the need for re-manipulation . An analysis of casting technique for all patients under eighteen years of age treated with closed reduction and cast immobilization for both-bone fractures of the forearm at a regional tertiary referral hospital over 7 years was undertaken. One-hundred and eighty-nine consecutive patients with 207 fractures were reviewed. No significant association was found between casting technique and failure rates (p=0.124). However, if manipulation and plaster was performed by a trainee, failure rates were significantly reduced when extension casting was utilized (p=0.029). Closed reduction and cast immobilization with the elbow in an extended position is an effective treatment option for both-bone forearm fractures in a paediatric population and is a safer option when performed by more junior staff-members.