Pulmonary Complications After Hip and Knee Arthroplasty in the United States, 2004-2014.

BACKGROUND: Pulmonary complications after total joint arthroplasty (TJA) are uncommon but have significant cost impact. Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are 2 of the 5 top procedures requiring inpatient stay within the United States. Subsequent pulmonary complications therefore may impose substantial cost burden for US health care. The purpose of this study was to describe the incidence, risk factors, and clinical implications of pulmonary complications (ie, pneumonia, respiratory failure, pulmonary embolism [PE], and aspiration) after TJA in the United States. METHODS: The National Inpatient Sample (NIS) was queried for all patients undergoing primary, elective THA and TKA between years 2004 and 2014. Pulmonary complications were defined as the occurrence of pneumonia, respiratory failure, PE, or aspiration after TJA. Demographic and clinical characteristics, inpatient cost, length of stay (LOS), and mortality were compared between patients with and without documented perioperative pulmonary complications. Given the stratified nature of the NIS database, estimates of incidence throughout the United States were made with application of trend weights to observed database frequencies. Analyses of estimated annual complication rates were made using χ tests. RESULTS: Between 2004 and 2014, an estimated 2,679,351 patients underwent elective primary THA. A total of 5,527,205 patients were estimated to have undergone elective primary TKA. THA 1.42% (95% CI, 1.37%-1.47%) and 1.71% (95% CI, 1.66%-1.76%) of TKA procedures were complicated by pneumonia, respiratory failure, PE, or aspiration. During this time, the incidence of perioperative pulmonary complications decreased from 1.57% (95% CI, 1.41%-1.73%) to 1.01% (95% CI, 0.92%-1.10%) after THA (P < .0001) and from 2.03% (95% CI, 1.88%-2.18%) to 1.33% (95% CI, 1.25%-1.42%) after TKA (P < .0001). The adjusted odds ratio (aOR) of experiencing a pulmonary complication was highest among patients with history of significant weight loss (aOR = 4.77; 99.9% CI, 3.97-5.73), fluid/electrolyte disorders (aOR = 3.33; 99.9% CI, 3.11-3.56), congestive heart failure (CHF; aOR = 3.32; 99.9% CI, 3.07-3.58), preexisting paralytic condition (aOR = 2.03; 99.9% CI, 1.57-2.61), and human immunodeficiency virus infection (aOR = 2.00; 99.9% CI, 1.06-3.78). Perioperative pulmonary complications were associated with increased LOS (THA = 3.03 days; 99.9% CI, 2.76-3.31; TKA = +2.72 days; 99.9% CI, 2.58-2.86), increased hospital costs (THA = +9163 US dollars; 99.9% CI, 8054-10,272; TKA = +7257 US dollars; 99.9% CI, 6650-7865), and increased mortality (THA: aOR = 121; 99.9% CI, 78-187; TKA: aOR = 150; 95% CI, 97-233). CONCLUSIONS: Despite a decline in overall incidence, perioperative pulmonary complications represent a significant potential source of perioperative morbidity and mortality. The current study highlights potential risk factors for pulmonary complications. Recognition of these factors may help to better stratify patients and mitigate risk of potential complications. This is particularly true of respiratory failure as it is associated with the high increases in resource utilization and mortality in this group.

Neighborhood Socioeconomic Status Affects Patient-Reported Outcome 2 Years After ACL Reconstruction.

BACKGROUND: Lower socioeconomic status (SES) is associated with worse patient-reported outcome (PRO) after orthopaedic procedures. In patients with anterior cruciate ligament (ACL) reconstruction, evaluating SES by use of traditional measures such as years of education or occupation is problematic because this group has a large proportion of younger patients. We hypothesized that lower education level and lower values for SES would predict worse PRO at 2 years after ACL reconstruction and that the effect of education level would vary with patient age. PURPOSE: To compare the performance of multivariable models that use traditional measures of SES with models that use an index of neighborhood SES derived from United States (US) Census data. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A cohort of 675 patients (45% female; median age, 20 years), were prospectively enrolled and evaluated 2 years after ACL reconstruction with questionnaires including the International Knee Documentation Committee (IKDC) questionnaire, the Knee injury and Osteoarthritis Outcome Score (KOOS), and the Marx activity rating scale (Marx). In addition, a new variable was generated for this study, the SES index, which used geocoding performed retrospectively to identify the census tract of residence for each participant at the time of enrollment and extract neighborhood SES measures from the 2000 US Census Descriptive Statistics. Multivariable models were constructed that included traditional measures of SES as well as the SES index, and the quality of models was compared through use of the likelihood ratio test. RESULTS: Lower SES index was associated with worse PRO for all measures. Models that included the SES index explained more variability than models with traditional SES. In addition, a statistically significant variation was found regarding the impact of education on PRO based on patient age for the IKDC score, the Marx scale, and 4 of the 5 KOOS subscales. CONCLUSION: This study demonstrates that lower neighborhood SES is associated with worse PRO after ACL reconstruction and that age and education have a significant interaction in this patient population. Future studies in patients who have undergone ACL reconstruction should attempt to account for neighborhood SES when adjusting for confounding factors; further, targeting patients from areas with lower neighborhood SES with special interventions may offer an opportunity to improve their outcomes.

The impact of solid organ transplant history on inpatient complications, mortality, length of stay, and cost for primary total shoulder arthroplasty admissions in the United States.

BACKGROUND: There is a growing population of patients with history of solid organ transplant (SOT) surgery among total joint patients. Patients with history of SOT have been found to have longer lengths of stay and higher inpatient hospital costs and complications rates after hip and knee arthroplasty. The purpose of this study was to determine whether this is true for shoulder arthroplasty in SOT patients. METHODS: The Nationwide Inpatient Sample was queried to describe relative demographic, hospital, and clinical characteristics, perioperative complications, length of stay, and total costs for patients with a history of SOT (International Classification of Diseases-9th Edition-Clinical Modificiation V42.0, V42.1, V42.7, V42.83) undergoing shoulder arthroplasty (81.80, 81.88) from 2004 to 2014. RESULTS: A weighted total of 843 patients (unweighted frequency = 171) and 382,773 patients (unweighted frequency = 77,534) with and without history of SOT, respectively, underwent shoulder arthroplasty. SOT patients were more often younger and more likely to be male, have Medicare, and undergo surgery in a large teaching institution in the Midwest or Northeast (P < .001). SOT patients had higher or similar comorbid disease prevalence for 27 of 29 Elixhauser comorbidities. The risk of any complication was significantly higher among SOT patients (15.5% vs. 9.3%, P = .007). SOT patients experienced inpatient admissions an average 0.27 days longer (P < .001) and $1103 more costly (P = .06) than non-SOT patients. CONCLUSIONS: Patients with history of SOT undergoing shoulder arthroplasty appear to remain a unique population due to their specific vulnerability to minor complications and inherently increased inpatient resource utilization.

Management of Posterior Cruciate Ligament Tibial Avulsion Injuries: A Systematic Review.

BACKGROUND: Tibial-sided avulsion injuries of the posterior cruciate ligament (PCL) generally require surgical intervention. No consensus exists concerning the optimal surgical treatment approach for these injuries. PURPOSE: To perform a systematic review investigating the open and arthroscopic surgical treatment modalities, outcomes, and complications of PCL tibial-sided bony avulsions. STUDY DESIGN: Systematic review; Level of evidence, 4. METHODS: The authors performed a systematic review of the literature utilizing PubMed and EMBASE from 1975 to present outlining open versus arthroscopic surgical repair of PCL bony avulsion injuries and comparing subjective and objective postoperative patient-reported outcomes, including Tegner, IKDC (International Knee Documentation Committee), and Lysholm scoring systems, as well as rates of patient complications. The quest was performed in June 2016, and searched terms included posterior cruciate ligament, PCL, bony, avulsion(s), tibial-sided, open, and arthroscopic. Inclusion criteria included English-language studies involving surgical fixation strategies for PCL tibial-sided bony avulsions. Exclusion criteria included non-English language, case studies/case series, and subject matter not pertaining to PCL bony avulsions. RESULTS: Twenty-eight articles comprising 637 patients met the criteria and were included in the final review. PCL injuries with a tibial-sided avulsion were the result of motor vehicle accidents in 68.4% of patients, with 59.0% of these injuries resulting from motorcycle accidents. The arthroscopic group had better IKDC grade A scores (78.9%), indicating a normal knee postoperatively, as compared with the open group (65.9%). The postoperative Lysholm scores were similar between the groups, with a mean of 95.0 in the arthroscopic group and 92.8 in the open group. The arthroscopic group also reported 100% return to preinjury level of activity, compared with 86.2% in the open group. The most common complication in both groups was arthrofibrosis, which was reported more often in the arthroscopic group (0%-35%) versus the open treatment group (0%-25%). CONCLUSION: In patients with displaced tibial-sided PCL avulsion fractures treated operatively, surgical approaches render similar outcomes and risks. While the arthroscopic group had somewhat higher subjective and objective knee outcome scores, it demonstrated a slightly higher rate of arthrofibrosis. The clear advantage of the arthroscopic approach is that concomitant intra-articular injuries seen on preoperative magnetic resonance imaging, such as meniscal tears or osteochondral loose fragments, can be addressed at the time of the index operation.

Predictors of Staphylococcus aureus Colonization and Results after Decolonization.

Protocols for the screening and decolonization of Staphylococcus aureus prior to total joint arthroplasty (TJA) have become widely adopted. The goals of this study were to determine: (1) whether implementation of a screening protocol followed by decolonization with mupirocin/vancomycin and chlorhexidine reduces the risk of revision compared with no screening protocol (i.e., chlorhexidine alone) and (2) whether clinical criteria could reliably predict colonization with MSSA and/or MRSA. Electronic medical records of primary patients undergoing TJA that were screened (n = 3,927) and were not screened (n = 1,751) for Staphylococcus aureus at least 4 days prior to surgery, respectively, were retrospectively reviewed. All patients received chlorhexidine body wipes preoperatively. Patients carrying MSSA and MRSA were treated preoperatively with mupirocin and vancomycin, respectively, along with the standard preoperative antibiotics and chlorhexidine body wipes. Screened patients were 50% less likely to require revision due to prosthetic joint infection compared to those not screened (p = 0.04). Multivariate regression models were poorly accurate in predicting colonization with MSSA (AUC = 0.58) and MRSA (AUC = 0.62). These results support the routine screening and decolonization of S. aureus prior to TJA.

Outcomes of Varus Valgus Constrained Versus Rotating-Hinge Implants in Total Knee Arthroplasty.

The stability of a total knee arthroplasty is determined by the ability of the prosthesis components in concert with supportive bone and soft tissue structures to sufficiently resist deforming forces transmitted across the knee joint. Constrained prostheses are used in unstable knees due to their ability to resist varus and valgus transformative forces across the knee. Constraint requires inherent rigidity, which can facilitate early implant failure. The purpose of this study was to describe the comparative indications for surgery and postoperative outcomes of varus valgus constrained knee (VVK) and rotating-hinge knee (RHK) total knee arthroplasty prostheses. Seven retrospective observational studies describing 544 VVK and 254 RHK patients with an average follow-up of 66 months (range, 7-197 months) were evaluated. Patients in both groups experienced similar failure rates (P=.74), ranges of motion (P=.81), and Knee Society function scores (P=.29). Average Knee Society knee scores were 4.2 points higher in VVK patients compared with RHK patients, indicating minimal mid-term clinical differences may exist (P<.0001). Absent collateral ligament support is an almost universal indication for RHK implantation vs VVK. Constrained device implantation is routinely guided by inherent stability of the knee, and, when performed, similar postoperative outcomes can be achieved with VVK and RHK prostheses.

Prevalence and Perioperative Outcomes of Off-Label Total Hip and Knee Arthroplasty in the United States, 2000-2010.

"Off-label use" refers to medical device utilization for purposes or subpopulations other than those approved by the United States Food and Drug Administration. The primary goal of this study was to determine the current epidemiology of off-label total hip and knee arthroplasties (THA and TKA, respectively) in the United States and to project further off-label use through 2040. Over the past decade, the prevalence of off-label THA and TKA was 30.4% and 37.0%, respectively, growing ~70% from 2000 to 2010. By 2040, the majority of THAs (86.1%) and TKAs (91.5%) could be off-label. The high prevalence of off-label arthroplasty and the dramatically shifting patient profile illustrated by these results highlight the need for continued medical device surveillance among on- and off label patients.

Complication, Survival, and Reoperation Rates Following Girdlestone Resection Arthroplasty.

Failed hip arthroplasty patients unsuitable for reimplantation may be offered Girdlestone resection arthroplasty (GRA). The purpose of this study was to detail complication and failure rates following GRA. Our results show that 66% (25/38), 34% (13/38), and 76% (29/38) of GRA patients experienced minor, major, and overall complications, respectively. Within 90 days of surgery, three patients required additional surgery and four died. Reoperation or death occurred an average of 26.3 (SD=3.5) and 55.6 (SD=76) months after surgery, respectively. Male gender and increasing comorbidity significantly predicted higher reoperation and mortality rates, P=0.01 and P=0.04, respectively. Complication and mortality rates following GRA are among the highest reported succeeding elective hip surgery for non-traumatic etiology.

Concomitant achondroplasia and developmental dysplasia of the hip.

Achondroplasia (ACH) is the most common form of hereditary dwarfism and presents with multiple musculoskeletal anomalies but is not normally associated with premature hip arthritis. Developmental dysplasia of the hip (DDH) is a spectrum of disease resulting in shallow acetabular depth and a propensity for chronic femoral subluxation or dislocation; it is among the most common causes of premature arthritis. This case report describes the diagnosis of symptomatic DDH in a patient with ACH and highlights difficulties of primary total hip arthroplasty (THA) as a treatment option. Intraoperative radiographic imaging is advised to ensure proper prosthesis placement. Femoral osteotomy may aid visualization, reduction, and avoidance of soft tissue injury. Concomitant ACH and DDH is a challenging problem that can be successfully treated with modified THA.

Activity levels and functional outcomes of young patients undergoing total hip arthroplasty.

The activity demands of young patients undergoing total hip arthroplasty (THA) have not been clearly defined. University of California Los Angeles (UCLA) activity score, Hip disability and Osteoarthritis Outcome Score (HOOS), Short Form-12 version 2 (SF-12v2), and Functional Comorbidity Index (FCI) questionnaires were administered to 70 young patients who had undergone THA (young THA group; ie, ≤30 years old), 158 general patients who had undergone THA (general THA group; ie, ≥31 years old), and 106 young, comorbidity-matched patients who had not undergone arthroplasty and had no significant hip disease (nonarthroplasty group). Mean postoperative UCLA activity scores were similar among groups (young THA group, 6.5; general THA group, 6.4; nonarthroplasty group, 6.6) before and after adjustment for comorbidity, sex, and race (P=.62 and P=.47, respectively). Adjusted analyses also found a negative association between postoperative activity and increases in comorbidity and female sex (P<.001). Patients in the young THA group reported higher expectations of postoperative activity (7.7) than those in the general THA group (7.1; P=.02). Postoperative HOOS results showed greater hip symptoms (P=.003) and poorer hip-related quality of life (P<.001) in the young THA group. Patient groups had similar postoperative SF-12v2 physical health scores (P=.31), although mental health scores were significantly higher in the general THA group (P<.001). The interesting finding of lower postoperative expectations, greater hip-related quality of life, and better mental health scores in the general THA group may indicate a need for better management of expectations in young patients undergoing THA, including a discussion of realistic gains in activity and potential comorbidity-related restrictions.

Can TKA be avoided? Alternate strategies.

In the properly selected patient, alternative options to total knee arthroplasty exist for the surgical treatment of knee joint disease. These procedures involve reestablishing healthy cartilage (i.e., bone marrow stimulation, grafting, autologous chondrocyte implantation), mechanical axis correction (i.e., osteotomy), and/or replacing pathologic knee compartments with prosthetic devices (i.e., unicompartmental and bicompartmental knee arthroplasty). Treatment modality selection varies based on a number of factors, including but not limited to age, activity level, treatment history, and lesion size, location, severity, and etiology. Reestablishing healthy cartilage in pathologic knees is dependent on the recipient's capacity and propensity to heal and regenerate new cartilage. Therefore, this technique is typically conducted in young patients, with small- to medium-sized focal chondral or osteochondral lesions. Osteotomy, unicompartmental knee arthroplasty, and bicompartmental knee arthroplasty do not have the same restrictions and are used for patients with larger, isolated knee lesions. This article reviews indications, efficacy, and advancements of existing surgical techniques for the repair or restoration of knee lesion injuries.

Replacing the wild type loxP site in BACs from the public domain with lox66 using a lox66 transposon.

BACKGROUND: Chromatin adjoining the site of integration of a transgene affects expression and renders comparisons of closely related transgenes, such as those derived from a BAC deletion series retrofitted with enhancer-traps, unreliable. Gene targeting to a pre-determined site on the chromosome is likely to alleviate the problem. FINDINGS: A general procedure to replace the loxP site located at one end of genomic DNA inserts in BACs with lox66 is described. Truncating insert DNA from the loxP end with a Tn10 transposon carrying a lox66 site simultaneously substitutes the loxP with a lox66 sequence. The replacement occurs with high stringency, and the procedure should be applicable to all BACs in the public domain. Cre recombination of loxP with lox66 or lox71 was found to be as efficient as another loxP site during phage P1 transduction of small plasmids containing those sites. However the end-deletion of insert DNA in BACs using a lox66 transposon occurred at no more than 20% the efficiency observed with a loxP transposon. Differences in the ability of Cre protein available at different stages of the P1 life cycle to recombine identical versus non-identical lox-sites is likely responsible for this discrepancy. A possible mechanism to explain these findings is discussed. CONCLUSIONS: The loxP/lox66 replacement procedure should allow targeting BACs to a pre-positioned lox71 site in zebrafish chromosomes; a system where homologous recombination-mediated "knock-in" technology is unavailable.

Context dependent function of APPb enhancer identified using enhancer trap-containing BACs as transgenes in zebrafish.

An enhancer within intron 1 of the amyloid precursor protein gene (APPb) of zebrafish is identified functionally using a novel approach. Bacterial artificial chromosomes (BACs) were retrofitted with enhancer traps, and expressed as transgenes in zebrafish. Expression from both transient assays and stable lines were used for analysis. Although the enhancer was active in specific nonneural cells of the notochord when placed with APPb gene promoter proximal elements its function was restricted to, and absolutely required for, specific expression in neurons when juxtaposed with additional far-upstream promoter elements of the gene. We demonstrate that expression of green fluorescent protein fluorescence resembling the tissue distribution of APPb mRNA requires both the intron 1 enhancer and approximately 28 kb of DNA upstream of the gene. The results indicate that tissue-specificity of an isolated enhancer may be quite different from that in the context of its own gene. Using this enhancer and upstream sequence, polymorphic variants of APPb can now more closely recapitulate the endogenous pattern and regulation of APPb expression in animal models for Alzheimer's disease. The methodology should help functionally map multiple noncontiguous regulatory elements in BACs with or without gene-coding sequences.