Faculty Bibliography

BACKGROUND:While technology-assisted total knee arthroplasty (TA-TKA) improves implant positioning, whether it confers improved clinical outcomes remains inconclusive. We sought to examine national TA-TKA utilization trends and to compare outcomes between TA-TKA and unassisted TKA (U-TKA). METHODS:Patients who underwent primary, elective TKA from 2010 to 2018 were identified using the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database. Demographic, perioperative, and 30-day outcomes were collected. Patients were stratified on the basis of whether they underwent TA-TKA, which included computer navigation and robotics, or U-TKA. The proportion of patients undergoing TKA using TA-TKA was calculated. One-to-one propensity-score matching paired patients undergoing TA-TKA or U-TKA. Independent samples t-tests and Mann-Whitney U tests were used to compare continuous variables, and chi-squared tests were used to compare categorical variables. RESULTS:Of the 402,284 TKA patients, 10,429 (2.6%) cases were performed using TA-TKA. Comparing the unmatched TA-TKA and U-TKA groups, race (p < 0.001), smoking status (p = 0.050), baseline functional status (p < 0.001), and body mass index (BMI) (p < 0.001) significantly differed. Propensity-score matching yielded 8633 TA-TKA and U-TKA pairs. The TA-TKA cohort had shorter hospital length of stay (LOS) (2.7 ± 2.5 versus 2.8 ± 1.9 days, p = 0.017) but similar operative times (92.4 ± 33.4 versus 92.6 ± 39.8 min, p = 0.670). Compared with the U-TKA group, the TA-TKA group had lower major complication (7.6% versus 9.4%, p < 0.001) and transfusion (3.9% versus 5.1%, p < 0.001) rates and higher rates of discharge to home (73.9% versus 70.4%, p < 0.001). Reoperation and readmission rates did not significantly differ between groups. CONCLUSIONS:TA-TKA utilization remains low among orthopedic surgeons. Compared with U-TKA, TA-TKA yielded improved perioperative and 30-day outcomes. Nonetheless, surgeons must consider the benefits and drawbacks of TA-TKA when determining the proper surgical technique and technology for each patient. LEVEL III EVIDENCE/METHODS:Retrospective cohort study.

BACKGROUND:Obesity is a recognized risk factor for severe knee osteoarthritis. However, it remains unclear how obesity prevalence trends in the current population undergoing total knee arthroplasty (TKA) compare with those seen in individuals not undergoing this procedure. In this study, we assessed the yearly trends in body mass index (BMI) and obesity rates between patients who have undergone primary TKA and those in the general population. METHODS:We retrospectively reviewed all patients ≥18 years of age from January 2013 through December 2020 who underwent primary, elective TKA and those who had an annual routine physical examination at our institution within the same period. Baseline demographic characteristics were collected. The independent samples t test was used to compare means and the chi-square test was used to compare proportions between the 2 cohorts, and a linear regression was used to determine the significance of the yearly trends. RESULTS:A total of 11,333 patients who underwent primary TKA and 1,158,168 patients who underwent an annual physical examination were included in this study. After adjusting for age, we found the mean BMI for the TKA group to be significantly greater (p < 0.001) every year compared with the annual physicals group. The proportion of patients who were categorized into any obesity class (BMI, ≥30 kg/m2), Class-I obesity (BMI, 30 to 34.9 kg/m2), Class-II obesity (BMI, 35 to 39.9 kg/m2), and Class-III obesity (BMI, ≥40 kg/m2) was significantly higher for the TKA group each year compared with the annual physicals group. An analysis of trends over time showed a significantly increasing trend (p < 0.001) in BMI and obesity rates for the annual physicals group, but a stable trend for patients undergoing TKA. CONCLUSIONS:Patients who underwent TKA continued to have higher BMI than the general population, which showed a steady increase over time. Physicians need to continue in their efforts to educate patients on weight management and healthy lifestyles to potentially delay the need for a surgical procedure. LEVEL OF EVIDENCE/METHODS:Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

INTRODUCTION/UNASSIGNED:Advanced age is considered a major risk factor for postoperative complications in total hip arthroplasty (THA). Consequently, older patients undergoing THA may require more detailed pre-procedural examinations and more healthcare resources postoperatively than younger patients. The purpose of this study was to compare discharge parameters and complication rates of THA in patients ⩾90 years old to those <90 years old. METHODS/UNASSIGNED:-tests. RESULTS/UNASSIGNED:= 1.000). CONCLUSIONS/UNASSIGNED:Although THA patients over 90 years of age had a longer LOS and differing discharge disposition, these patients had similar complications compared to their younger counterparts. Thus, our study supports similar efficacy of THA in patients 90 years and older relative to younger THA candidates.

Dual mobility designs in total arthroplasty allow for increased range of motion prior to impingement and dislocation. While valuable for reducing dislocation, dual mobility has its own unique complication profile that includes intraprosthetic dislocation, corrosion, and femoral notching. Despite these relatively rare complications, dual mobility articulations are valuable options for patients at higher risk of dislocation-both early and contemporary reports on dual mobility in total hip arthroplasty suggest that it can reduce the risk of dislocation without leading to unacceptable rates of complication or early revision. Cost analyses and longer follow-up studies on newer dual mobility designs will help determine the future of dual mobility in total hip arthroplasty.

BACKGROUND:Image-guided joint aspirations used to assist the diagnosis of periprosthetic joint infection (PJI) may commonly result in a dry tap-or insufficient fluid for culture and cell count analysis. Dry tap aspirations are painful and invasive for patients and often utilize a subsequent saline lavage to obtain a microbiology sample. Currently, there is a paucity of the literature addressing predictors that could suggest whether a dry tap will occur. The purpose of this study was to examine the effects of various factors on "dry tap" occurrence in patients with suspected PJI following total hip arthroplasty (THA). METHODS:A retrospective review was performed among THA patients suspected for PJI who received image-guided joint aspiration procedures at our institution from May 2016 to February 2020. The procedural factors included the imaging modality used for aspiration, anatomic approach, needle gauge size used, and the presence of a trainee. The patient-specific factors included number of prior ipsilateral hip surgeries, femoral head size, ESR/CRP values, and BMI. RESULTS:In total, 336 patients met our inclusion criteria. One hundred and twenty hip aspirations resulted in a dry tap (35.7%) where the patients underwent a saline lavage. Among the procedural and patient-specific factors, none of the factors were found to be statistically different between the two cohorts nor conferred any greater odds of a dry tap occurring. CONCLUSION/CONCLUSIONS:No associations with dry tap occurrence were found among the procedural and patient-specific factors studied. Further research is needed to identify additional factors that may be more predictive of dry taps.

BACKGROUND:The purpose of this study is to determine if the number and types of patient-reported drug allergies are associated with prosthetic joint infection (PJI) and functional outcomes following total joint arthroplasty (TJA). METHODS:This is a retrospective review of all patients who underwent a primary, elective total hip (THA) or knee arthroplasty (TKA) over a 10-year period at a single academic institution. Demographic, clinical information, and number and type of patient-reported drug allergy was collected. Univariate and multivariate logistic regressions were performed to identify risk factors for PJI and risk of PJI based on number of allergies. Univariate analysis was also performed to identify if the number of patient-reported allergies affected functional outcome scores. RESULTS:Of 31,109 patients analyzed, there were 941 (3%) revisions for infection (491 knees and 450 hips). At least one allergy was reported by 16,435 (52.8%) patients, with a mean of 1.2 ± 1.9. Those who underwent revision for infection had a significantly higher number of reported allergies (1.68 ± 1.9 vs 1.23 ± 1.9, P < .0005, 95% confidence interval -0.58 to 0.33). On univariate regression the number of allergies independently predicted revision TJA for infection (P < .0001) as did age, gender, body mass index, and smoking status. On multivariate regression for each additional patient-reported allergy, risk of PJI increased by 1.11 times (95% confidence interval 1.07-1.14, P < .0001). Number of patient-reported allergies did not predict 3-month or 1-year functional outcome scores. CONCLUSION/CONCLUSIONS:Patients with a higher number of reported allergies may be at increased risk of PJI following TJA. LEVEL OF EVIDENCE/METHODS:Prognostic Level II.

BACKGROUND:The use of technology such as navigation and robotic systems may improve the accuracy of component positioning in total hip arthroplasty (THA), but its impact on patient-reported outcome measures (PROMs) remains unclear. This study aims to elucidate the association between the use of intraoperative technology and PROMs in patients who underwent primary THA. METHODS:We retrospectively reviewed a consecutive series of patients who underwent primary THA between 2016 and 2020 and answered PROM questionnaires. Patients were separated into 3 groups depending on intraoperative technology utilization: computer-assisted navigation, robotic-assisted, or no technology (conventional) THA. Forgotten Joint Score-12 and Hip disability and Osteoarthritis Outcome Score, Joint Replacemen scores were collected at various time points. Demographic differences were assessed with chi-square and analysis of variance. Mean scores between groups were compared using univariate analysis of covariance, controlling for all significant demographic differences. RESULTS:Of the 1960 cases identified, 896 used navigation, 135 used robotics, and 929 used no technology. There were significant statistical differences in one-year Hip disability and Osteoarthritis Outcome Score, Joint Replacement scores (85.23 vs 85.95 vs 86.76, respectively; P = .014) and two-year Forgotten Joint Score-12 scores (64.72 vs 73.35 vs 74.63, respectively; P = .004) between the 3 groups. However, these differences did not exceed the mean clinically important differences. Length of stay was statistically longest for patients who underwent conventionally performed THA versus navigation and robotics (2.22 vs 1.46 vs 1.91, respectively; P < .001). Surgical time was significantly longer for cases performed using robotics versus navigation and conventionally (119.61 vs 90.35 vs 95.35, respectively; P < .001). CONCLUSION/CONCLUSIONS:Statistical differences observed between all modalities are not likely to be clinically meaningful with regard to early patient-reported outcomes. Although intraoperative use of technology may improve the accuracy of implant placement, these modalities have not yet translated into improved early reported functional outcomes. LEVEL III EVIDENCE/UNASSIGNED:Retrospective cohort.

BACKGROUND:Venous thromboembolism (VTE), defined as pulmonary embolism or deep venous thrombosis, is a rare but serious complication following revision total hip arthroplasty (RTHA) and revision total knee arthroplasty (RTKA). Previous studies show that obesity may be associated with an increased risk for pulmonary embolism, wound complications, and infection. With no current universal standard of care for VTE prophylaxis, we sought to determine whether aspirin prescribed (ASA) is safe and effective in obese patients undergoing RTHA/RTKA. METHODS:). RESULTS:The cohort comprised of 335 patients with a normal BMI, 511 were overweight, 408 obese, 232 severely obese, and 92 morbidly obese. Total VTE rates were statistically similar between BMI groups (0.90% vs 0.78% vs 0.74% vs 0.43% vs 0%, P = .89). There were no differences in bleeding rates (0.90% vs 0% vs 0% vs 0.43% vs 0%, P = .08), wound complications (0.30% vs 0.20% vs 0.25% vs 0% vs 0%, P = .93), infection (1.49% vs 1.57% vs 0.98% vs 1.29% vs 1.09%, P = .66), or mortality (0% vs 0.20% vs 0% vs 0% vs 0%, P = .72). CONCLUSION/CONCLUSIONS:ASA is safe and effective for VTE prevention in obese patients with similar complication rates to nonobese patients undergoing RTHA/RTKA.

As perioperative protocols have improved, there has been a reduction in the rates of key complications after hip and knee arthroplasty. Likewise, as we have been able to make patients more comfortable postoperatively, hospital length of stay has decreased and in some centers, hip and knee arthroplasty is now routinely performed as an outpatient. While the number of surgeons offering this option and patients choosing to have procedures performed as an outpatient grows, many questions revolve around this movement. This article will review the data supporting outpatient arthroplasty, the business and legal aspects involved, if surgeons can align with their hospital to offer these services, and how tightly knit and highly organized teams are key to the success of safely offering hip and knee arthroplasty on an outpatient basis.

BACKGROUND:Patellar maltracking is a potential surgical complication following total knee arthroplasty (TKA) and can result in anterior knee pain, recurrent patellar dislocation, and damage to the medial patellar soft tissue stabilizers. Data remain unclear as to whether the patellar button should be revised during a revision TKA (rTKA) if changing the component implant system. Our study examines whether retaining the original patellar button during an rTKA using a different implant system affects patellar tracking. METHODS:A retrospective cohort study of rTKA patients between August 2011 and June 2019 was performed at an urban, tertiary referral center. Patients were divided into 2 cohorts depending on whether their retained patella from their primary TKA was of the same (SIM) or different implant manufacturer (DIM) as the revision system used. Radiographic measurements were performed on preoperative and postoperative knee radiographs and differences were compared between the 2 groups. Baseline demographic data were also collected. RESULTS:Of the 293 consecutive, aseptic rTKA cases identified, 122 underwent revision in the SIM cohort and 171 in the DIM cohort. There were no demographic differences between the groups. No statistical significance was calculated for differences in preoperative and postoperative patellar tilt or Insall-Salvati ratio between the groups. The DIM group was found to have more lateral patellar translation (-0.01 ± 6.09 vs 2.68 ± 7.61 mm, P = .001). However, when calculating differences in the magnitude of the translation (thereby removing differences due to laterality), no difference was observed (0.06 ± 3.69 vs 0.52 ± 4.95 mm, P = .394). CONCLUSION/CONCLUSIONS:No clinically significant differences in patellar tracking were observed when the original patellar component was retained and a different revision implant system was used. Given the inherent risks of bone loss and fracture with patellar component revision, surgeons performing rTKA may retain the primary patella if it is well fixed and can still expect appropriate patellar tracking regardless of the revision implant system used. LEVEL OF EVIDENCE/METHODS:III, Retrospective cohort study.