Faculty Bibliography

Background/UNASSIGNED:There is a paucity of literature assessing whether payer type has an impact on postoperative patient-reported outcomes (PROs) after total knee arthroplasty (TKA). The aim of this study was to comparatively evaluate TKA PROs among patients with commercial and Medicare insurance. Methods/UNASSIGNED:We conducted a single-center, retrospective review of patients operated between January 2017 and March 2018. Knee Disability and Osteoarthritis Outcome Score Junior (KOOS-Jr) and Veterans RAND 12 Health Survey (VR-12) Physical Component (VR-12 PCS) and Mental Component (VR-12 MCS) PRO scores were collected prospectively at baseline and 12 weeks postoperatively via an electronic patient rehabilitation application. Univariable and multivariable linear regressions were utilized to assess the effects of patient insurance type on PRO. Results/UNASSIGNED:> .05). Conclusions/UNASSIGNED:After adjusting for patient-specific variables, PROs are similar at baseline and 12 weeks postoperatively between commercial and Medicare cohorts. For TKA candidates with similar baseline demographics, surgeons can expect similar perioperative PROs regardless of insurance type.

Oxinium is an alternative bearing surface designed to emulate the superior wear and scratch properties of ceramic femoral heads in total hip arthroplasty while minimizing the risk for brittle fracturing. However, recent studies have indicated that hip dislocation following total hip arthroplasty may be a risk factor for catastrophic failure of the femoral head. Here, we report on a novel case of a catastrophic Oxinium head and polyethylene liner failure in the absence of previous hip dislocation or trauma and review the probable failure mechanism. This report underscores the need to be vigilant about proper acetabular cup and liner seating, particularly in the setting of Oxinium femoral head use. In the event of Oxinium head failure, metallosis may compromise stabilizing soft tissues including the abductors. Dual-mobility articulation, which was successful in this case, is one option to consider when the risk for chronic redislocation is elevated.

The number of total knee arthroplasties performed in the United States is growing, and a leading cause of failure is postoperative knee instability from suboptimal coronal or sagittal balancing. This article reviews native knee anatomy as well as several guiding principles of total knee arthroplasty such as limb axis, femoral referencing, and implant constraint. Next, techniques that can be used by the surgeon to achieve ideal sagittal balance and coronal balance are discussed in detail. Finally, due to the growing use of computer and robotic technologies in knee replacement, the impact of advanced technologies on total knee arthroplasty balancing and alignment is reviewed. An in-depth understanding of these topics will enable surgeons to optimize the outcome of their total knee arthroplasty patients.

Despite the overall successful outcomes following primary total knee arthroplasty (TKA) and the concept that a well-balanced TKA yields a more successful result, concerns still remain in the reported literature regarding the patellofemoral joint. Diminished outcomes have been associated with poorly balanced or placed patella implants. The effect of different techniques to achieve flexion-extension balance and the use of posterior stabilized (PS) versus cruciate retaining (CR) implant designs on patellofemoral balancing has not been previously studied. The purpose of this study is to utilize a validated computational analysis software to simulate the effects of varying implant positions and sizes of femoral components. The patellofemoral retinaculum (PFR) load was significantly affected by some conditions, while others did not reach significance. The proximal-distal implant position with knee flexion angle (p < 0.001), the implant size (p < 0.001), and the implant bearing type (CR/PS) (p < 0.05) were significant. For the proximal-distal implant position and knee flexion angle, a more proximal implant position (elevating the joint line) increased the PFR load from 15 to 30°, and a more proximal implant position reduced retinaculum load from 60 to 135°. However, at 45°, implant position does not affect retinaculum load. Achieving the appropriate balance between the dynamic nature of both the tibiofemoral and the patellofemoral interaction in TKA has proven to be complex and challenging to manage. Balancing of a TKA is essential to the proper functioning and overall longevity of the implant. These results demonstrate that patellofemoral balance is affected by implant size and position during flexion-extension gap balancing.

BACKGROUND:Patients with chronic hepatitis C (HCV) have had extremely high complication rates after total hip arthroplasty (THA). We sought to compare perioperative complication rates between untreated and treated HCV in THA patients and to compare these rates between patients treated with 2 different therapies (interferon vs direct antiviral agents). METHODS:A multicenter retrospective database query was used to identify patients diagnosed with HCV who underwent THA between 2006 and 2016. All patients (n = 105) identified were included and divided into 2 groups: untreated (n = 63) and treated (n = 42) HCV; treated patients were further subdivided into those receiving interferon (n = 16) or direct antiviral agent therapies (n = 26). Comparisons between the treated and untreated groups were made with respect to demographic data, comorbidities, preoperative viral load, Model for End-Stage Liver Disease score, and all surgical and medical complications; a subgroup analysis of the treated patients was also performed. Separate independent t-tests or Mann-Whitney U tests were conducted for continuous variables. Categorical variables were compared using the chi-squared test of independence. RESULTS:A greater number of untreated patients were human immunodeficiency virus infected (P = .01), while a reduced number of treated patients were either former or current smokers (P = .004). The untreated group had greater surgical complication rates (25.4% vs 4.8%; P = .007), with a higher rate of periprosthetic joint infection (14.3% vs 0%, P = .01). For treated patients, no differences were observed between treatment types for postsurgical complications. CONCLUSION/CONCLUSIONS:Treatment for HCV prior to THA appears to be associated to fewer postoperative complications, primarily periprosthetic joint infection. Although further investigation is warranted, strong consideration should be given to treating patients for HCV prior to elective THA.

Despite the development of newer preventative measures, the rate of infection continues to be approximately 1% for patients undergoing total joint arthroplasty (TJA). The extent of the infection can range from a mild superficial infection to a more serious periprosthetic joint infection (PJI). PJIs not only play a significant role in the clinical well-being of the TJA patient population, but also have substantial economic implications on the health care system. Several approaches are currently being used to mitigate the risk of PJI after TJA. The variety of prophylactic measures to prevent infection after TJA must be thoroughly discussed and evaluated.

Introduction/UNASSIGNED:Preliminary analysis of accelerometry measurements has shown physical activity may not increase significantly after total knee arthroplasty (TKA). This study evaluates the effect of TKA on physical activity accelerometry measurements and body mass index (BMI). Methods/UNASSIGNED:tests. Results/UNASSIGNED:Twenty-three patients from the OAI database were identified for the paired analysis. They were evaluated at a mean postoperative follow-up of 15 months. There were no statistically significant differences between the post-TKA group and pre-TKA group for the accelerometry variables and BMI, though patients experienced a significant improvement in knee function and pain relief measures included in this analysis. Discussion/UNASSIGNED:Although TKA can successfully restore function and relieve pain, there remains no good evidence that neither physical activity nor BMI improve postoperatively. Conclusion/UNASSIGNED:No significant differences in physical activity and BMI were observed after TKA in this study.