TKA is More Durable Than UKA for Morbidly Obese Patients: A Two-Year Minimum Follow-Up Study

BackgroundUnicompartmental knee arthroplasty (UKA) indications have expanded during the past two decades to include some morbidly obese patients (body mass index (BMI) > 40 kg/m²). Few published studies have compared UKA and total knee arthroplasty (TKA) in this unique patient subgroup with conflicting observations.MethodsWe retrospectively compared 89 mobile bearing UKA (71 patients) and 201 TKA (175 patients) performed at a single institution with a minimum 2-year follow-up (mean 3.4 years). Demographic characteristics were similar for both patient cohorts. A detailed medical record review was performed to assess the frequency of component revision, revision indications, minor secondary procedures (components retained), and infections.ResultsUKA was more frequently associated with clinical failure (29.2% vs 2.5%, P < .001) and component revision (15.7% vs 2.5%, P < .001), TKA was more frequently associated with extensor mechanism complications or knee manipulation (5.5% vs 0.0%, P = .02), and there was no difference in the infection rate (3.0% vs 2.2%, P = 1.0).ConclusionEarly complications were lower following UKA but were outweighed by higher component revision rates for arthritis progression and implant failure. The study findings suggest that TKA provides a more predictable mid-term outcome for morbidly obese patients considering knee arthroplasty surgery.     

Migration Patterns for Revision Total Knee Arthroplasty in the United States as Reported in the American Joint Replacement Registry

BackgroundRevision total knee arthroplasty (TKA) is associated with a higher complication rate and a greater cost when compared to primary TKA. Based on patient choice, referral, or patient transfers, revision TKAs are often performed in different institutions by different surgeons than the primary TKA. The aim of this study is to evaluate the effect of hospital size, teaching status, and revision indication on the migration patterns of failed primary TKA in patients 65 years of age and older.MethodsAll primary and revision TKAs reported to the American Joint Replacement Registry from January 2012 through March 2020 were included and merged with the Centers for Medicare and Medicaid Services database. Migration was defined as a patient having a primary TKA and revision TKA performed at separate institutions by different surgeons.ResultsIn total, 9167 linked primary and revision TKAs were included in the analysis. Overall migration rates were significantly higher from small (<100 beds; P = .019), non-teaching institutions (P = .002) driven primarily by patients diagnosed with infection. Infection patients had significantly higher migration rates from small (46.8%, P < .001), non-teaching (43.5%, P < .001) institutions, while migration rates for other causes of revision were statistically similar. Most patients migrated to medium or large institutions (84.7%) for revision TKA rather than small institutions (15.3%, P < .001) and to teaching (78.3%) rather than non-teaching institutions (21.7%, P < .001).ConclusionThere is a diagnosis-dependent referral bias that affects the migration rates of infected primary TKA from small non-teaching institutions leading to a flow of more medically complex patients to medium and large teaching institutions for infected revision TKA.     

Computer-Navigated and Robotic-Assisted Total Knee Arthroplasty: Increasing in Popularity Without Increasing Complications

BackgroundData on the clinical impact of computer navigation (CN) and robotic assistance (RA) in total knee arthroplasty (TKA) are mixed. This study aims to describe modern utilization trends in CN-TKA, RA-TKA, and traditionally-instrumented (TD) TKA and to assess for differences in postoperative complications and opioid consumption by procedure type.MethodsA national database was queried to identify primary, elective TKA patients from 2015 to 2020. Trends in procedural utilization rates were assessed. Differences in 90-day postoperative complications and inpatient opioid consumption were assessed. Multivariate regression analyses were performed to account for potential confounders.ResultsOf the 847,496 patients included, 49,317 (5.82%) and 24,460 (2.89%) underwent CN-TKA and RA-TKA, respectively. CN-TKA utilization increased from 5.64% (2015) to 6.41% (2020) and RA-TKA utilization increased from 0.84% (2015) to 5.89% (2020). After adjusting for confounders, CN-TKA was associated with lower periprosthetic joint infection (P = .001), pulmonary embolism (P < .001), and acute respiratory failure (P = .015) risk compared to traditional (TD) TKA. RA-TKA was associated with lower deep vein thrombosis (P < .001), myocardial infarction (P = .013), and pulmonary embolism (P = .001) risk than TD-TKA. Lower postoperative day 1 opioid usage was seen with CN-TKA and RA-TKA than TD-TKA (P < .001). Lower postoperative day 0 opioid consumption was also seen in RA-TKA (P < .001).ConclusionFrom 2015 to 2020, there was a relative 13.7% and 601.2% increase in CN-TKAs and RA-TKAs, respectively. This trend was associated with reductions in hospitalization duration, postoperative complications, and opioid consumption. These data support the safety of RA-TKA and CN-TKA compared to TD-TKA. Further investigation into the specific indications for these technology-assisted TKAs is warranted.     

Unicompartmental Knee Arthroplasty Patients Have Lower Joint Awareness and Higher Function at 5 Years Compared to Total Knee Arthroplasties: A Matched Comparison

BackgroundThe purpose of this study was to evaluate postoperative outcomes at minimum 5-year follow-up in patients following unicompartmental knee arthroplasty (UKA) compared to a matched cohort of total knee arthroplasty (TKA) patients.MethodsPatients who had primarily medial compartment osteoarthritis (OA) who met criteria for medial UKA underwent TKA or medial UKA between 2014 and 2015 at a single institution, matched for age, sex, and body mass index. There were 127 UKAs in 120 patients and 118 TKAs in 116 patients included with minimum 5-year follow-up (range, 6 to 8). Mean age was 69 years (range, 59 to 79) and 71 years (range, 62 to 80) in the UKA and TKA groups, respectively (P = .049).ResultsPatients who underwent UKA had significantly higher mean (±SD) Forgotten Joint Scores (87 ± 20 versus 59 ± 34, P < .001); higher Knee Society Scores (88 ± 14 versus 75 ± 21, P < .001); and lower Numeric Pain Rating Scores (0.8 ± 1.6 versus 1.9 ± 2.2, P < .001). Survivorship free from all-cause revision was 96% (95% CI = 93%-99%) and 99% (95% CI = 97%-100%) at 5 years for TKA and UKA, respectively (P = .52). There were 8 both component revisions in the TKA group within 5 years from the date of surgery and 2 UKA conversions to TKA after 5-year follow-up.ConclusionPatients who have medial compartment OA and underwent UKA had significantly lower joint awareness, decreased pain, improved function, and higher satisfaction compared to matched TKA patients at minimum 5-year follow-up while maintaining excellent survivorship.     

Differences in Pain,Opioid Use,and Function Following Unicompartmental Knee Arthroplasty compared to Total Knee Arthroplasty

BackgroundWe sought to determine if immediate postsurgical pain, opioid use, and clinical function differed between unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA).MethodsA single-institution database was utilized to identify patients who underwent elective total joint arthroplasty between 2016 and 2019.ResultsIn total, 6616 patients were identified: 98.20% TKA (6497) and 1.80% (119) UKA. UKA patients were younger, had lower body mass index, and more often male than the TKA cohort. Aggregate opioid consumption (75.94 morphine milligram equivalents vs 136.5 morphine milligram equivalents; P < .001) along with the first 24-hour and 48-hour usage was significantly less for UKA as compared to TKA. Similarly, pain scores (1.98 vs 2.58; P < .001) were lower for UKA while Activity Measure for Post-Acute Care mobilization scores were higher (21.02 vs 18.76; P < .001). UKA patients were able to be discharged home on the day of surgery 37% of the time as compared to 2.45% of TKA patients (P < .0001). Notably, when comparing UKA and TKA patients who were discharged home on the day of surgery, no differences regarding pain scores, opioid utilization, or mobilization were observed.ConclusionUKA patients are younger, have lower body mass index and American Society of Anesthesiologists scores, and more often male than TKA patients. UKA patients had significantly shorter length of stay than TKA patients and were discharged home more often than TKA patients, on both the day of surgery and following hospital admission. Most notably, UKA patients reported lower pain scores and were found to require 45% lower opioid medication in the immediate postsurgical period than TKA patients. Surprisingly, UKA and TKA patients discharged on the day of surgery did not differ in terms of pain scores, opioid utilization, or mobilization, suggesting that our rapid rehabilitation UKA protocols can be successfully translated to outpatient TKAs with similar outcomes.Level III EvidenceRetrospective Cohort Study.     

Does Unicompartmental Knee Replacement Offer Improved Clinical Advantages Over Total Knee Replacement in the Treatment of Isolated Lateral Osteoarthritis? A Matched Cohort Analysis From an Independent Center

BackgroundThe purpose of this study is to compare the functional and radiographic results, perioperative complications, satisfaction rate, and mid-term survivorship after unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) for the treatment of lateral compartmental knee osteoarthritis (LCKO).MethodsBetween March 2007 and September 2017, we identified 35 patients with primary TKAs and 121 patients with lateral UKAs (LUKAs) for LCKO with a minimum follow-up of 2 years (mean 5.3 years, range 2-12.4). The matched variables were age, gender, operation side, body mass index, American Society of Anesthesiologist grade, initial diagnosis, osteoarthritis grade in lateral compartment, and follow-up time. All patients were assessed using the Oxford Knee Score, Hospital for Special Surgery score, range of motion, length of hospital stay, satisfaction, and complications. Survivorship of UKA and TKA implants was also compared.ResultsAt last follow-up, LUKA had a significantly better postoperative Oxford Knee Score, Hospital for Special Surgery score, range of motion, shorter length of hospital time, and higher satisfaction rate than matched TKA group. There were significant differences regarding patellar tendon injury (P = .043), superficial wound infection (P = .028), patellar snapping or impingement (P = .047), and stiffness (P < .001). Five-year survivorships free from revision were similar in both groups (99.2% vs 97.1%, P = .347).ConclusionLUKA for LCKO demonstrated more favorable 5-year results in comparison with TKA. Furthermore, LUKA achieved comparable mid-term survivorship and was less likely to suffer from wound infection and knee stiffness, although not overall surgical complications.     

Is Conversion TKA a Primary or Revision? Clinical Course and Complication Risks Approximating Revision TKA Rather Than Primary TKA

BackgroundConversion total knee arthroplasty (convTKA) is associated with increased resource utilization and costs compared with primary TKA. The purpose of this study is to compare 1) surgical time, 2) hospitalization length (LOS), 3) complications, 4) infection, and 5) readmissions in patients undergoing convTKA to both primary TKA and revision TKA patients.MethodsThe American College of Surgeons National Surgical Quality Improvement Project database was queried from 2008 to 2018. Patients undergoing convTKA (n = 1,665, 0.5%) were defined by selecting Current Procedural Terminology codes 27,447 and 20,680. We compared the outcomes of interest to patients undergoing primary TKA (n = 348,624) and to patients undergoing aseptic revision TKA (n = 8213). Univariate and multivariate logistic regression was performed to identify the relative risk of postoperative complications.ResultsCompared with patients undergoing primary TKA, convTKA patients were younger (P < .001), had lower body mass index (P < .001), and were less likely to be American Society of Anesthesiologist class III/IV (P < .001). These patients had significantly longer operative times (122.6 vs 90.3 min, P < .001), increased LOS (P < .001), increased risks for any complication (OR 1.94), surgical site infection (OR 1.84), reoperation (OR 2.18), and readmissions (OR 1.60) after controlling for confounders. Compared with aseptic TKA revisions, operative times were shorter (122.6 vs 148.2 min, P < .001), but LOS (2.91 vs 2.95 days, P = .698) was similar. Furthermore, relative risk for any complication (P = .350), surgical site infection (P = .964), reoperation (P = .296), and readmissions (P = .844) did not differ.ConclusionConversion TKA procedures share more similarities with revision TKA rather than primary TKA procedures. Without a distinct procedural and diagnosis-related group, there are financial disincentives to care for these complex patients.Level of EvidenceII.     

Narcotic Consumption in Opioid Naïve Patients Undergoing Unicompartmental and Total Knee Arthroplasty

BackgroundTotal knee arthroplasty (TKA) is associated with increased risk of prolonged narcotic requirement compared to unicompartmental knee arthroplasty (UKA). The purpose of the current study is to compare acute postoperative narcotic consumption between the 2 procedures and quantify narcotic consumption.MethodsFrom October 2017 to August 2019 patients were surveyed for four weeks to determine the amount and duration of opioids consumed and requirement for continued narcotics. Among 976 opioid naïve patients, 314 (32%) underwent UKA and 662 (68%) underwent TKA. Patients were analyzed according to specific narcotic prescribed. Total morphine equivalent dose (MED), number of pills, duration, refill percentage, and usage percentage for 4 weeks were calculated for each procedure.ResultsMED used in the postoperative period was lower in patients undergoing UKA than TKA (200 ± 195 vs 259 ± 250 MED, P = .002). Total number of pills consumed and duration of use was less in UKA compared to TKA regardless of which opioid was prescribed. A smaller proportion of patients required narcotics for 4 weeks after UKA (32% vs 43%, P < .001), and fewer UKA patients required narcotic refills (14% vs 27%, P < .001). Sixty pills of any 1 type of narcotic was sufficient for 90% of UKA patients and over 75% of TKA patients.ConclusionUKA is associated with less narcotic consumption, shorter duration of use, less refills, and lower likelihood of narcotic requirement for 4 weeks. We report narcotic consumption patterns for both procedures to aid surgeons in judicious postoperative prescribing.Level of EvidenceThis is a level III retrospective cohort study reviewing narcotic use in over 900 consecutive opioid naïve patients undergoing UKA or TKA.     

High Bundled Payment Costs Following Total Hip and Knee Arthroplasty in African Americans

BackgroundConcerns exist that minorities who utilize more resources in an episode-of-care following total hip (THA) and knee arthroplasty (TKA) may face difficulties with access to quality arthroplasty care in bundled payment programs. The purpose of this study is to determine if African American patients undergoing TKA or THA have higher episode-of-care costs compared to Caucasian patients.MethodsWe queried Medicare claims data for a consecutive series of 7310 primary TKA and THA patients at our institution from 2015 to 2018. We compared patient demographics, comorbidities, readmissions, and 90-day episode-of-care costs between African American and Caucasian patients. A multivariate regression analysis was performed to identify the independent effect of race on episode-of-care costs.ResultsCompared to Caucasians, African Americans were younger, but had higher rates of pulmonary disease and diabetes. African American patients had increased rates of discharge to a rehabilitation facility (20% vs 13%, P < .001), with higher subacute rehabilitation ($1909 vs $1284, P < .001), home health ($819 vs $698, P = .022), post-acute care ($5656 vs $4961, P = .008), and overall 90-day episode-of-care costs ($19,457 vs $18,694, P = .001). When controlling for confounding comorbidities, African American race was associated with higher episode-of-care costs of $440 (P < .001).ConclusionAfrican American patients have increased episode-of-care costs following THA and TKA when compared to Caucasian patients, mainly due to increased rates of home health and rehabilitation utilization. Further study is needed to identify social variables that can help reduce post-acute care resources and prevent reduction in access to arthroplasty care in bundled payment models.     

Robotic-Assisted Total Knee Arthroplasty: What are Patients’ Perspectives,Understanding and Expectations?

BackgroundThe rate of using robotic-assisted total knee arthroplasty (RA-TKA) has increased markedly. Understanding how patients view the role of robotics during total knee arthroplasty (TKA) informs shared decision making and facilitate efforts to appropriately educate patients regarding the risks and benefits of robotic assistance.MethodsA self-administered questionnaire was completed by 440 potential TKA patients at the time of their surgery scheduling. Participants answered 25 questions regarding RA-TKA, socioeconomic factors, and their willingness to pay (WTP) for RA-TKA. Logistic regressions were used to determine if population characteristics and surgeon preferences influenced the patients’ perceptions of RA-TKA.ResultsThere were 39.7% of respondents who said that they had no knowledge regarding RA-TKA. Only 40.7% of participants had expressed a desire for RA-TKA to be used. There were 8.7% who were WTP extra for the use of RA-TKA. Participants believed that the main 3 benefits of RA-TKA compared to conventional methods were: more accurate implant placement (56.2%); better results (49.0%); and faster recovery (32.1%). The main 3 patient concerns were harm from malfunction (55.2%), reduced surgeon role in the procedure (48.1%), and lack of supportive research (28.3%). Surgeon preference of RA-TKA was associated with patient’s willingness to have RA-TKA (odds ratio 4.60, confidence interval 2.98-7.81, P < .001), and with WTP extra for RA-TKA (odds ratio 2.05, confidence interval: 1.01-4.26, P = .049).ConclusionPatient knowledge regarding RA-TKA is limited. Nonpeer-reviewed online information may make prospective TKA candidates vulnerable to misinformation and aggressive advertising. The challenge for orthopaedic surgeons is to re-establish control and reliably educate patients about the proven advantages and disadvantages of this emerging technology.     

Major National Shifts to Outpatient Total Knee Arthroplasties in the United States: A 10-Year Trends Analysis of Procedure Volumes,Complications, and Healthcare Utilizations (2010 to 2020)

BackgroundThe removal of total knee arthroplasty (TKA) from inpatient-only lists accelerated changes in orthopaedic surgical practices across the United States. This study aimed to (1) quantify the annual volume of inpatient/outpatient primary TKAs; (2) compare patient characteristics before/after the year 2018; and (3) compare annual trends in 30-day readmissions, 30-day complications, and healthcare utilization parameters for inpatient/outpatient TKAs.MethodsThe National Surgical Quality Improvement Program was reviewed (January 2010 to December 2020) for patients who underwent primary TKA (n = 470,456). The primary outcome was annual volumes of inpatient/outpatient TKA. Secondary outcomes included 30-day readmissions, 30-day reoperations, and 30-day major/minor complications. Demographic characteristics and healthcare utilization parameters (hospital lengths of stay and discharge dispositions) were compared between cohorts via Chi-square goodness-of-fit tests.ResultsOverall, 89% had inpatient TKA (n = 416,972) and 11% had outpatient TKA (n = 53,854). Between 2017 and 2020, annual volumes of outpatient TKA increased by 1,925 (1,019 to 20,633), while inpatient TKA decreased by 53% (61,874 to 29,280). Patients who had outpatient TKA after 2018 were older (P < .001), predominantly males (P < .001), more commonly White (P < .001), and had a greater proportion of American Society of Anesthesiologists class III (P < .001). The inpatient cohort had higher rates of 30-day readmissions, reoperations, and complications. Average length of stay and nonhome discharges decreased for both cohorts.ConclusionOutpatient TKA increased 20-fold at NSQIP hospitals. The changes in comorbidity profiles and the increase in volumes of outpatient TKA were not associated with a rise in cumulative 30-day readmissions and complications. Further research and policy endeavors should focus on identifying patients who still require or benefit from inpatient TKA.     

10-Year Cumulative Incidence and Indications for Revision Total Knee Arthroplasty Among Patients Who Have Sickle Cell Disease

BackgroundLiterature regarding total knee arthroplasty (TKA) outcomes in sickle cell disease (SCD) is limited. Moreover, 10-year survivorship of SCD implants is unknown. This study aimed to observe 10-year cumulative incidence and indications for revision TKA in patients who did and did not have SCD.MethodsPatients who underwent primary TKA were identified using a large national database. The SCD patients were matched by age, sex, and a comorbidity index to a control cohort in a 1:4 ratio. The 10-year cumulative incidence rates were determined using Kaplan–Meier survival analyses. Multivariable analyses were conducted using Cox proportional hazard modeling. Chi-squared analyses were conducted to compare indications for revision between cohorts. In total, 1,010 SCD patients were identified, 100,000 patients included in the unmatched control, and 4,020 patients included in the matched control.ResultsCompared to the unmatched control cohort, SCD patients exhibited higher 10-year all-cause revision (HR: 1.86; P < .001) with higher proportions of revisions for periprosthetic joint infection (PJI) (P < .001), aseptic loosening (P < .001), and hematoma (P < .001). Compared to the matched control, SCD patients had higher 10-year all-cause revision (Hazard Ratio (HR): 1.39; P = .034) with a higher proportion of revisions for PJI (P = .044), aseptic loosening (P = .003), and hematoma (P = .019).ConclusionIndependent of other comorbidities, SCD patients are more likely to undergo revisions for PJI, aseptic loosening, and hematoma compared to patients who do not have SCD. Due to the high-risk of these complications, perioperative and postoperative surgical optimization should be enforced in SCD patients.     

Surgical Helmet Systems Are Associated With a Lower Rate of Prosthetic Joint Infection After Total Knee Arthroplasty: Combined Results From the New Zealand Joint Registry and Surgical Site Infection Improvement Programme

BackgroundThis study aimed to identify the risk factors, in particular the use of surgical helmet systems (SHSs), for prosthetic joint infection (PJI) after total knee arthroplasty (TKA). Data recorded by the New Zealand Surgical Site Infection Improvement Programme (SSIIP) and the New Zealand Joint Registry (NZJR) were combined and analyzed.MethodsPrimary TKA procedures performed between July 2013 and June 2018 that were recorded by both the SSIIP and NZJR were analyzed. Two primary outcomes were measured: (1) PJI within 90 days as recorded by the SSIIP and (2) revision TKA for deep infection within 6 months as recorded by the NZJR. Univariate and multivariate analyses were performed to identify risk factors for both outcomes with results considered significant at P < .05.ResultsA total of 19,322 primary TKAs were recorded by both databases in which 97 patients had a PJI within 90 days as recorded by the SSIIP (0.50%), and 90 patients had a revision TKA for deep infection within 6 months (0.47%) as recorded by the NZJR. An SHS was associated with a lower rate of PJI (adjusted odds ratio [OR] = 0.50, P = .008) and revision for deep infection (adjusted OR = 0.55, P = .022) than conventional gowning. Male sex (adjusted OR = 2.6, P < .001) and an American Society of Anesthesiologists score >2 were patient risk factors for infection (OR = 2.63, P < .001 for PJI and OR = 1.75, P = .017 for revision for deep infection).ConclusionUsing contemporary data from the SSIIP and NZJR, the use of the SHS was associated with a lower rate of PJI after primary TKA than conventional surgical gowning. Male sex and a higher American Society of Anesthesiologists score continue to be risk factors for infection.     

High Mortality After Total Knee Arthroplasty Periprosthetic Joint Infection is Related to Preoperative Morbidity and the Disease Process but Not Treatment

BackgroundPeriprosthetic joint infection (PJI) mortality rate is approximately 20%. The etiology for high mortality remains unknown. The objective of this study was to determine whether mortality was associated with preoperative morbidity (frailty), sequalae of treatment, or the PJI disease process itself.MethodsA multicenter observational study was completed comparing 184 patients treated with septic revision total knee arthroplasty (TKA) to a control group of 38 patients treated with aseptic revision TKA. Primary outcomes included time and the cause of death. Secondary outcomes included preoperative comorbidities and Charlson Comorbidity Index (CCMI) measured preoperatively and at various postoperative timepoints.ResultsThe septic revision TKA cohort experienced earlier mortality compared to the aseptic cohort, with a higher mortality rate at 90 days, 1, 2, and 3 years after index revision surgery (P = .01). There was no significant difference for any single cause of death (P > .05 for each). The mean preoperative CCMI was higher (P = .005) in the septic revision TKA cohort. Both septic and aseptic cohorts experienced a significant increase in CCMI from the preoperative to 3 years postoperative (P < .0001 and P = .002) and time of death (P < .0001 both) timepoints. The septic revision TKA cohort had a higher CCMI 3 years postoperatively (P = .001) and at time of death (P = .046), but not one year postoperatively (P = .119).ConclusionCompared to mortality from aseptic revision surgery, septic revision TKA is associated with earlier mortality, but there is no single specific etiology. As quantified by changes in CCMI, PJI mortality was associated with both frailty and the PJI disease process, but not treatment.     

Long-Term Functional Outcomes and Quality of Life at Minimum 10-Year Follow-Up After Fixed-Bearing Unicompartmental Knee Arthroplasty and Total Knee Arthroplasty for Isolated Medial Compartment Osteoarthritis

BackgroundThe aim of this study is to compare the long-term functional outcome and quality of life between total knee arthroplasty (TKA) and fixed-bearing unicompartmental knee arthroplasty (UKA) for the treatment of isolated medial compartment osteoarthritis.MethodsBetween 2000 and 2008, a total of 218 patients underwent primary UKA at our tertiary hospital. A TKA group was matched through 1:1 propensity score matching and adjusted for age, gender, body mass index, preoperative knee flexion, and function scores. All patients had medial compartment osteoarthritis. The patients were assessed with the range of motion, Knee Society Knee Score and Knee Society Function Score, Oxford Knee Score, Short Form-36 physical component score (PCS) and mental component score preoperatively, at 6 months, 2 years, and 10 years. Patients’ satisfaction, expectation fulfillment, and minimal clinically important difference were analyzed.ResultsThere were no differences in baseline characteristics between groups after propensity score matching (P > .05). UKA had greater knee flexion at all time points. Although the Knee Society Function Score was superior in UKA by 5.5, 3, and 4.3 points at 6 months, 2 years, and 10 years, respectively (P < .001), these differences did not exceed the minimal clinically important difference (Knee Society Knee Score 6.1). There were no significant differences in the Oxford Knee Score and Short Form-36 physical component score/mental component score. At 10 years, similar proportions of UKA and TKA were satisfied (90.8% vs 89.9%, P = .44) and had expectation fulfillment (89.4% vs 88.5%, P = .46). Between 2 and 10 years, all function scores deteriorated significantly for both groups (P < .01).ConclusionUKA and TKA are excellent treatment modalities for isolated medial compartment osteoarthritis, with similar functional outcomes, quality of life, and satisfaction at 10 years.     

Racial and Ethnic Disparities in Short-Stay Total Knee Arthroplasty

BackgroundThe purpose of this study was to understand racial and ethnic disparities in hospital-based, Medicare-defined outpatient total knee arthroplasty (TKA). We aimed to determine the following: 1) whether there are differences in preoperative characteristics or postoperative outcomes in outpatient TKA between racial/ethnic groups and 2) trends in outpatient TKA volume, based on race/ethnicity.MethodsThis was a retrospective cohort study of a large national database. Outpatient TKAs performed between 2012 and 2018 were identified. Patient demographics, comorbidities, and 30-day postoperative outcomes were compared between White, Black, Asian, and Hispanic patients.ResultsOf 54,183 outpatient patients, 85.6% were White, 7.4% Black, 2.6% Asian, and 4.1% Hispanic. Black patients had the highest body mass index, and there were higher rates of diabetes among all minority groups (P < .001). All minority groups were more likely to be discharged to a rehabilitation or a skilled care facility compared to White patients (P < .001). Annual percentage increases in outpatient TKA were most pronounced for Asians and Hispanics and least pronounced among Blacks, when compared to White patients.ConclusionThe outcomes of outpatient TKA are impacted by risk factors that reflect underlying disparities in healthcare. As joint arthroplasties have come off the inpatient-only list and procedures move to ambulatory settings, these disparities will likely magnify and impact outcomes, costs, and access points. Extensive preoperative optimization and interventions that target medical and social factors may help to reduce these disparities in TKA and increase access among minority patients.Level of EvidenceIII, retrospective cohort study.     

Racial Differences in Manipulation Under Anesthesia Rates Following Total Knee Arthroplasty

BackgroundDespite the extensive literature on racial disparities in care and outcomes after total knee arthroplasty (TKA), data on manipulation under anesthesia (MUA) is lacking. We aimed to determine (1) the relationship between race and rate of (and time to) MUA after TKA, and (2) annual trends in racial differences in MUA from 2013 to 2018.MethodsThis retrospective cohort study (using 2013-2018 Medicare Limited Data Set claims data) included 836,054 primary TKA patients. The primary outcome was MUA <1 year after TKA; time from TKA to MUA in days was also recorded. A mixed-effects multivariable model measured the association between race (White, Black, Other) and odds of MUA. Odds ratios (OR) and 95% confidence intervals (CI) were reported. A Cochran Armitage Trend test was conducted to assess MUA trends over time, stratified by race.ResultsMUA after TKA occurred in 1.7%, 3.2% and 2.1% of White, Black, and Other race categories, respectively (SMD = 0.07). After adjustment for covariates, (Black vs White) patients had increased odds of requiring an MUA after TKA: odds ratio (OR) 1.97, 95% confidence intervals (CI) 1.86-2.10, P < .0001. Moreover, White (compared to Black) patients had significantly shorter time to MUA after TKA: 60 days (interquartile range [IQR] 46-88) versus 64 days (interquartile range [IQR] 47-96); P < .0001. These disparities persisted from 2013 through 2018.ConclusionContinued racial differences exist for rates and timing of MUA following TKA signifying the continued need for efforts aimed toward understanding and eliminating inequalities that exist in total joint arthroplasty (TJA) care.     

Conversion Total Knee Arthroplasty: Prior Fracture or Osteotomy Around the Knee Leads to Increased Resource Utilization

BackgroundPrior knee surgery before total knee arthroplasty (TKA) puts patients at higher risk of inferior outcomes and increased care cost. This study compares intraoperative and postoperative variables including procedure duration, components, length of stay, readmission, complications, and reoperations among patients undergoing conversion TKA.MethodsPrimary TKA from a single-surgeon database identified 130 patients with prior knee surgery to form a “conversion” cohort. One-to-one matching identified 130 patients of similar age, American Society of Anesthesiologists score, body mass index, and gender without prior knee surgery for comparison. Perioperative and 90-day postoperative variables were compared between patients with and without prior surgery, within the conversion group based on the type of prior surgery, and whether the prior surgery was bony or soft tissue.ResultsThe conversion group had longer mean operative time (96.1 vs 90.0 minutes, P = .01), higher revision component utilization (8.5% vs 0.8%, P = .005), and higher calculated blood loss (1440 vs 1249 mL, P = .004). Thirty-eight patients with prior fracture or osteotomy were compared to the remaining 92 patients in the conversion group and showed longer operative time (107.1 vs 91.3 minutes, P < .001), higher 90-day readmissions (18.4% vs 3.3%, P = .003), more complications (23.7% vs 8.7%, P = .021), and greater utilization of revision components (26.3% vs 1.1%, P < .001).ConclusionPatients undergoing conversion TKA required increased resource utilization, particularly patients with a prior osteotomy or fracture. Policymakers should consider these variables, as they did in conversion THA, in adding a code to account for increased case complexity and resource utilization.     

Prior Knee Arthroscopy Increases the Failure Rate of Subsequent Unicompartmental Knee Arthroplasty

BackgroundIn selected patients, knee arthroscopy is performed prior to unicompartmental knee arthroplasty (UKA) to treat symptomatic mechanical pathology, delay arthroplasty, and assess the knee compartments. The purpose of this study was to determine if knee arthroscopy prior to UKA is associated with increased rates of UKA failure or conversion to total knee arthroplasty (TKA).MethodsData was collected from the Humana insurance database from 2007-2017. Patients who underwent knee arthroscopy within two years prior to UKA were identified and matched with controls based on age, gender, Charlson Comorbidity Index, smoking status, and obesity. Rates of conversion to TKA and failure for various causes were compared between cohorts.ResultsPrior to propensity matching, 8353 UKA patients met inclusion criteria. Of these, 1079 patients (12.9%) underwent knee arthroscopy within two years of UKA and were matched to 1079 patients (controls) who did not undergo knee arthroscopy in the two years preceding UKA. No differences in demographics/comorbidities existed among cohorts. Compared to controls, the knee arthroscopy cohort was more likely to experience failure for aseptic loosening (2.4% vs 1.1%; OR 2.166; P = .044) and significantly more likely to require conversion to TKA (10.4% vs 4.9%; OR 2.113; P < .001) within two years of UKA.ConclusionKnee arthroscopy within two years of UKA is associated with an increased rate of UKA conversion to TKA and a higher rate of UKA failure from aseptic loosening. Although clinicians should be mindful of this association when performing knee arthroscopy in patients who may be indicated for future UKA, further research is needed to better characterize these findings.     

Advanced Age Is Not a Barrier to Total Knee Arthroplasty: A Detailed Analysis of Outcomes and Complications in an Elderly Cohort Compared With Average Age Total Knee Arthroplasty Patients

BackgroundLife expectancy and higher complication rates have made the routine use of total knee arthroplasty (TKA) in elderly patients disputed by some authors. The purpose of this study was to assess patient and implant survivorship, complication and revision rates, and patient-reported outcomes (PROMS) in a cohort of patients aged above 80 years undergoing TKA. A comparison with a propensity matched cohort of patients of average age within our database for TKA was performed.MethodsA retrospective review of prospectively collected data identified 644 patients over the age of 80 years undergoing a TKA within a 14-year period. After calculating the average age of all TKA patients within the reviewed database, a cohort deemed average age was created within 1 standard deviation of the average age and matched using the following criteria: gender, surgeon, diagnosis, procedure type, and year. The primary outcomes were survivorship of the implant and the patient. The secondary outcomes were complications, transfusion rates, discharge destination, and PROMS.ResultsThe revision rate was low for both groups (P = .051). Implant survivorship at 10 years was similar (P = .07). Mortality rate was higher in the elderly (P < .001). General complication rate was higher in the elderly (P = .031). Surgical complications rates were similar (P = .702). The PROMS at final follow-up were 4% lower in the elderly (P < .001).ConclusionTKA in the elderly is a safe procedure. With measures minimizing the perioperative complications and blood loss, the outcome can be expected to be similar to patients of average age. The projected implant and patient survivorship in the elderly cohort is long enough to suggest that TKA in the elderly could have a high impact on remaining quality of life.Level III retrospective study.