Posterior tibial slope considered as an important addition to the CPAK classification system.

Introduction: Coronal Plane Alignment of the Knee (CPAK), is an informative way to classify native knee alignment types, but does not consider posterior tibial slope, an important variable in knee kinematics. We hypothesized that tibial slope would have a significant effect on knee kinematics and warrant consideration in addition to the CPAK system. Methods: We examined 335 adult patients with osteoarthritis receiving total knee arthroplasty. We measured the lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), and posterior tibial slope angle (PTS). Knees were categorized into CPAK classes and subdivided into types 'A' (PTS 8°) or 'B' (PTS >8°). We recorded pre-and-post operative knee flexion, and extension/flexion gaps in all subjects. Results: CPAK classes VII-IX were not seen. Classes I and II comprised a plurality of all knees. One-third of all knees were type B. CPAK classes III, IV, and VI had greater type B proportions, but this was not statistically significant. Type B knees had greater flexion both pre-op (p < .001) and post-op (p = .043); type A knees had greater flexion improvement pre-to-post operatively (p = .045). Type A knees had greater medial and lateral flexion-extension gap change pre-operatively (p = .021) and (p = .027), respectively. Type B knees had greater medial-lateral gap imbalance preoperatively in both flexion and extension. Discussion/conclusion: Our results suggest that there are important pre and post-operative differences in medial and lateral femorotibial gap balance between type A and B knees that require consideration for intra-operative balancing. Differences in knee flexion further solidify that PTS is an important variable that affects kinematics before and after TKA. We propose the addition of PTS types A and B to the existing CPAK classes. This is an easy and logical way to create a comprehensive classification system in both coronal and sagittal planes that captures further differences in knee kinematics.

Transition to Robotic Total Knee Arthroplasty With Kinematic Alignment is Associated With a Short Learning Curve and Similar Acute-Period Functional Recoveries.

Background Robotic instruments are increasingly being used in total knee arthroplasty (TKA). The adoption of robotics has allowed surgeons a new level of precision and facilitated the adoption of a kinematic approach in TKA. We sought to examine one surgeon's transition from a traditional mechanical alignment technique to a modified kinematic approach by comparing short-term recovery outcomes of robotic TKA patients with those who underwent traditionally instrumented TKAs. Methodology We examined six-week and six-month postoperative data from 99 traditionally instrumented, mechanically aligned and 66 kinematically aligned robotic TKA patients between January 2021-October 2021 and October 2021-April 2022, respectively. Robotic surgery was performed with VELYS™ (DePuy Synthes, Warsaw, IN, USA) a semi-active, imageless, table-affixed, robotic TKA solution. Results Robotic and traditionally instrumented TKAs did not differ significantly in any functional outcome measures examined, including pain scores, use of assistive devices, or range of motion at six weeks postoperatively. Robotic TKA patients had a better range of motion in knee flexion than traditional TKA patients at six months postoperatively. There were no differences in surgical complications or rates of manipulation under anesthesia within one year postoperatively. Robotic surgery tourniquet times exhibited a steep drop off and equaled traditional methods after only two robotic surgeries were performed. Conclusions Transition to a kinematic, semi-active, robotic TKA demonstrated encouraging results by demonstrating acute-period recovery of function consistent with the current standard of care, as well as a better range of motion at six months postoperatively. The learning curve of this new-to-market device was shorter than previous research on the transition to robotic TKA. Clear advantages of transitioning to robotic instrumentation by any specific functional measure are yet to be elucidated. Further randomized trials are necessary to characterize long-term outcomes.

Smoking status and maternal weight trajectories during pregnancy and postpartum: Preliminary results from a pilot study.

OBJECTIVE: To preliminarily examine throughout pregnancy and 12 months postpartum: 1) the critical timings of abnormal gestational weight gain (GWG) among quitters and non-quitters; 2) the consequences of abnormal GWG on weight retention during postpartum; 3) the potential difference in GWG by timing of quitting (early vs. late). METHODS: We included 59 pregnant smokers (49 quitters and 10 non-quitters) from two clinical pilot studies. Smoking status and weight were repeatedly measured throughout pregnancy and postpartum. Weight trajectories were analyzed using mixed models with smoking cessation status, pregnancy week or postpartum month, their interaction term, and potential confounders. RESULTS: At enrollment, mothers had a mean BMI of 28.7 (SD, 7.2) and mean age of 30.1 years (SD, 5.8). Both groups had a linear increase in GWG, but quitters had a much higher rate of GWG (0.87 vs. 0.22 pounds/week) than non-quitters throughout pregnancy. Before delivery, 63.3% of quitters and 20.0% of non-quitters had excessive total GWG, while 12.2% of quitters and 60.0% of non-quitters had inadequate total GWG (p-value=0.004). Early quitters (<21 weeks) had a higher risk of excessive GWG (85.0%) than late quitters (≥21 weeks, 36.4%) (p-value=0.026). After delivery, quitters' weight remained stable following a rapid weight loss, whereas non-quitters' weight increased continuously. CONCLUSIONS: Non-quitters have a high risk of inadequate GWG, while quitters, especially early quitters, have a high risk of excessive GWG. The group difference in weight trajectories lasted from conception to postpartum.