Tough Questions in Total Hip and Total Knee Arthroplasty.

Some of today's tough questions surrounding hip and knee arthroplasty involve modifiable risks, bilateral staging, physiotherapy, postoperative activity, venous thromboembolism and infection prophylaxis, pain management, and outpatient settings. The available literature is reviewed to provide answers to difficult questions facing the orthopaedic surgeon. Preoperative questions focus on patient selection, medical optimization, and appropriateness for outpatient surgery. Modifiable risk factors for undergoing lower extremity arthroplasty include obesity, smoking, and diabetic control. Guidelines are presented to advise which patients are suitable candidates to undergo the procedure in an outpatient setting. Perioperative questions arise regarding the use of first-generation cephalosporins for prophylaxis, topical vancomycin powder, tranexamic acid, negative-pressure dressings, local intra-articular injections, and optimal timing of staged bilateral procedures. Postoperative questions are often raised about the necessity of formal postoperative physical therapy, when can patients resume driving after arthroplasty, should patients return to high-level sporting activity, and how long should patients be advised to take antibiotic prophylaxis for dental procedures.

Mid-Term Clinical Outcomes and Survivorship of a Second-Generation Modular Revision Knee System.

INTRODUCTION: Revision knee systems have adapted to the challenges of revision knee arthroplasty with offset stems, augments, cones, and various levels of constraint. The purpose of this study is to review the mid-term outcomes of a second-generation modular knee revision system. MATERIALS AND METHODS: A retrospective review was conducted from 2011 through 2014 on all patients who underwent knee arthroplasty with the Vanguard® 360 revision knee system (Zimmer Biomet, Warsaw, Indiana). Patients were included in the study if they were eligible for five-year minimum follow up and had signed a general research consent. The initial query revealed 253 patients (267 knees) that met inclusion criteria. Complications assessed were manipulation under anesthesia (MUA) and revision of any component. Statistical analysis using paired t-test was performed to evaluate changes in clinical outcomes and Kaplan-Meier survival analysis. RESULTS: Mean follow up was 6.6 years. The Vanguard® 360 knee system was used in four (1.5%) primary total knee arthroplasties (TKAs), 66 (24.7%) second-stage reimplantation TKAs after infection, and 197 (73.8%) aseptic revisions. There were significant improvements in knee range of motion and Knee Society Scores (all p<0.05). Manipulations under anesthesia were performed in 17 knees (6.4%). A total of 41 knees (15.4%) failed for any cause and required re-revision surgery. Of these, 11 (4.1%) failed due to aseptic loosening. Kaplan-Meier analysis revealed overall survival to endpoint of aseptic loosening to be 96.4% (95% CI: ±1.2%) at five years and 95.2% (95% CI: ±1.4%) at 9.5 years. When comparing survivorship in patients who underwent initial revision for aseptic indications compared with those whose underwent revision for second-stage reimplantation after infection, Kaplan-Meier survival to endpoint of revision for any cause at 9.5 years was higher for patients with aseptic than septic indication for TKA (87.0% [95% CI: ±2.4%] vs. 75.3% [95% CI: ±5.4%], p=0.0156). CONCLUSION: The findings of this study demonstrate greater than 95% aseptic survivorship with the use of the Vanguard® revision knee system at mid-term follow up.

Revision of Unicompartmental Knee Arthroplasty to Total Knee Arthroplasty: Is It as Good as a Primary Result?

BACKGROUND: Unicompartmental knee arthroplasty (UKA) is touted as a more conservative, bone- and tissue-sparing procedure than total knee arthroplasty (TKA). Similarly, revision of UKA to TKA is generally a simpler procedure than revision of TKA to TKA and can be accomplished with primary TKA components in most cases. The purpose of this study was to review a consecutive series of patients undergoing revision of failed UKA to TKA to determine if etiology is similar to that reported in recent literature and evaluate if the results align more with primary TKA vs revision of TKA to TKA. METHODS: A query of our private practice registry from 1996 to 2015 revealed 184 patients (193 knees) who underwent revisions of failed UKA with minimum 2-year follow-up. The mean age was 63.5 (37-84) years, body mass index was 32.3 (19-57) kg/m2, and interval after UKA was 4.8 (0-35) years. The most prevalent indications for UKA revision were aseptic loosening (42%) arthritic progression (20%), and tibial collapse (14%). RESULTS: At 6.1-year mean follow-up (2-20), 8 knees (4.1%) required re-revision, which is similar to what we reported at 5.5 years in a group of primary TKA patients (6 of 189; 3.2%) and much lower than what we observed at 6.0 years in a recent study of aseptic revision TKA patients (35 of 278; 12.6%). In the study group, Knee Society clinical and function scores improved from 50.8 and 52.1 preoperatively to 83.4 and 67.6 at the most recent evaluation. Re-revisions were for aseptic loosening (3), instability (2), arthrofibrosis (2), and infection (1). CONCLUSIONS: Compared to published individual institution and national registry data, re-revision rates of failed UKA are equivalent to revision rates of primary TKA and substantially better than re-revision rates of revision TKA. These data should be used to counsel patients undergoing revision UKA to TKA.