In Vitro Investigation of Column Fixation Constructs for Periacetabular Osteotomy: Which Provide the Greatest Stiffness and Strength?

Background: Periacetabular osteotomy (PAO) is an effective surgical procedure for managing acetabular dysplasia. The purpose of this study was to analyze the biomechanical properties of novel PAO constructs that incorporate orthopaedic trauma techniques. We hypothesize that these fixation methods will create a stiffer construct that tolerates higher loads to failure. Methods: Twenty bio-composite hemi-pelvises underwent PAO with the following fixation configurations: Group A: 4 iliac crest (IC) screws; Group B: 3 IC screws; Group C: 2 IC screws, 1 retrograde anterior column (AC) screw, and 1 lateral compression type-2 (LC2) screw directed from the anterior inferior iliac spine to the posterior inferior iliac spine; Group D: 1 AC screw, 1 LC2 screw, 1 posterior column screw; Group E: 2 LC2 screws, 1 AC screw. Constructs were loaded to failure on a material testing hydraulic press, and ultimate strength, stiffness, and osteotomy displacement were measured. Results: The highest load to failure was seen in group D (2511 N), which was significantly more than groups A (1528 N, P = .0114) and B (1348 N, P < .0001). The stiffest construct was group E (602 N/mm) compared to groups A (315 N/mm, P = .0439) and B (243 N/mm, P = .0008). Failure occurred most often with a fracture in the posterior column. Conclusions: This study supports column fixation methods used in orthopaedic trauma for PAO as biomechanically advantageous to traditional fixation techniques. These constructs may be beneficial to patients with weight-bearing concerns or early rehabilitation needs.

Does interaction occur between risk factors for revision total knee arthroplasty?

INTRODUCTION: Several risk factors for revision TKA have previously been identified, but interactions between risk factors may occur and affect risk of revision. To our knowledge, such interactions have not been previously studied. As patients often exhibit multiple risk factors for revision, knowledge of these interactions can help improve risk stratification and patient education prior to TKA. MATERIALS AND METHODS: The State Inpatient Databases (SID), part of the Healthcare Cost and Utilization Project (HCUP), were queried to identify patients who underwent TKA between January 1, 2006 and December 31, 2015. Risk factors for revision TKA were identified, and interactions between indication for TKA and other risk factors were analyzed. RESULTS: Of 958,944 patients who underwent TKA, 33,550 (3.5%) underwent revision. Age, sex, race, length of stay, Elixhauser readmission score, urban/rural designation, and indication for TKA were significantly associated with revision (p < 0.05). Age was the strongest predictor (p < 0.0001), with younger patients exhibiting higher revision risk. Risks associated with age were modified by an interaction with indication for TKA (p < 0.0001). There was no significant interaction between sex and indication for TKA (p = 0.535) or race and indication for TKA (p = 0.187). CONCLUSIONS: Age, sex, race, length of stay, Elixhauser readmission score, urban/rural designation, and indication for TKA are significantly associated with revision TKA. Interaction occurs between age and indication.

Incidence and Clinical Risk Factors of Post-Operative Complications following Primary Total Hip Arthroplasty: A 10-Year Population-Based Cohort Study.

Background: Total hip arthroplasty (THA) has become a growing treatment procedure for debilitating hip pathologies. Patients experienced post-operative complications and revision surgeries according to large THA registries. To fully understand the short-term and long-term post-operative outcomes following THA, the purpose of this study is to examine the incidence of post-operative complications following primary THA and to examine how this trend has changed over 10 years within community hospitals in the US using large databases. Methods: This study queried the State Inpatient Database (SID) for primary THA between 2006 and 2015. Individual patients were followed forward in time until the first instance of a post-operative complication. The multivariable logistic regression analyses were computed to examine which post-operative complications were independent predictors of pre-operative comorbidities. Results: Median age of patients was 67 years, and 56% of patients were female. Females with avascular necrosis (AVN) as an indication for THA had a 27% higher risk of complication. Females with osteoarthritis (OA) as an indication for THA had a 6% higher risk of complication. Post-operative complications occurred with higher frequencies in the first two months of THA and the highest risks of THA complications within the first 6 months. Conclusion: The most common indication is OA in elders with primary THA. Females and those of black ethnicity showed the greatest risks of THA complications. Data from our large study can be used to understand post-operative complications and readmissions after THA. Our study also provides data on risk factors associated with these complications.

Low rate of malalignment using the tibial traction triangle for infrapatellar nailing of distal tibia fractures.

OBJECTIVES: To report on the immediate postoperative alignment of distal tibia fractures (within 10 cm of the tibial plafond) treated with infrapatellar intramedullary nailing (IMN) using the tibial traction triangle (TTT). METHODS: We performed a retrospective cohort study at a Level-I academic trauma center, with eighty-one skeletally mature patients with closed distal tibia fractures treated over a 10-year period with closed infrapatellar intramedullary nailing, without fibula fixation, using the TTT. The primary outcome measure is primary malalignment ≥5°. RESULTS: Primary malalignment occurred in 4 (4.9%) patients, all in the coronal plane. Mean coronal plane alignment was 1.72° valgus (range 3° varus to 8° valgus). No sagittal malalignment occurred. The fibula was intact in 5 (6.2%) cases. No patients underwent fibula fixation or blocking screw placement. Intra-articular extension occurred in 28 (34.6%) cases. Mean fracture distance from the plafond was 5.98 cm. Thirty-one patients had a fracture within 5 cm of the plafond, where malalignment was noted in 2 (6.5%) patients. CONCLUSIONS: This is the first analysis of a large cohort of patients with distal tibia fractures treated with the TTT. Use of this device leads to a very low rate of primary malalignment with infrapatellar nailing, even in extremely distal fractures. We recommend consideration of this device as one more adjunct to help treat these difficult fractures successfully.

Reduction of Opioid Use With Enhanced Recovery Program for Total Knee Arthroplasty.

BACKGROUND: Adequate pain control after total knee arthroplasty (TKA) is critically important to achieve early mobilization, shorten the length of hospital stay, and reduce postoperative complications. At Veterans Affairs North Texas Health Care System (VANTHCS) in Dallas, we implemented a multidisciplinary enhanced recovery after surgery (ERAS) protocol to deal with increasing length of stay and postoperative pain. We hypothesize that this protocol will reduce the overall opioid burden and decrease inpatient hospital length of stay in our TKA population. METHODS: A retrospective review of all TKAs performed by a single surgeon at VANTHCS from 2013 to 2018 was conducted. A postoperative ERAS protocol was implemented in 2016. We compared perioperative opioid use and LOS between cohorts before and after protocol implementation. RESULTS: Inpatient length of stay between cohorts was reduced from 66.8 hours for the standard of care (SOC) period to 22.3 hours in the ERAS cohort. Inpatient opioid use measured by total oral morphine equivalent doses averaged 169.5 mg and 66.7 mg for SOC and ERAS cohorts, respectively (P = .0001). Intraoperative use of opioids decreased from 57.4 mg in the SOC cohort to 10.5 mg in the ERAS cohort (P = .0001). Postanesthesia care unit (PACU) opioid use decreased from 13.6 mg (SOC) to 1.3 mg (ERAS) (P = .0002). There was no significant difference in complications between cohorts (P = .09). CONCLUSIONS: Initiating a multidisciplinary ERAS protocol for TKA at VANTHCS significantly reduced inpatient length of stay and perioperative opioid use with no deleterious effects on complication rates. The ERAS protocol has major medical and financial implications for our unique VA population and the VA health care system.

Standardized total knee arthroplasty pathway improves outcomes in minority patients.

OBJECTIVES: Inferior total knee arthroplasty (TKA) outcomes are reported in minority populations. Standardized TKA pathways improve outcomes but have not been studied extensively in minority populations. This study evaluated the impact of TKA pathway standardization at an urban teaching hospital that predominantly treats minority patients. STUDY DESIGN: Retrospective cohort study. METHODS: This study compared primary TKA outcomes before and after implementation of a standardized multidisciplinary pathway that emphasized preoperative education and discharge planning, preemptive multimodal pain control, and early rehabilitation. Patients were grouped as "nonpathway" (n = 144) or "pathway" (n = 182) based on whether they underwent TKA before or after pathway implementation. Outcomes included length of stay (LOS), patient-controlled analgesia (PCA) use, blood transfusion, postoperative hemoglobin, complications, and discharge disposition. Analysis involved negative binomial and multiple logistic regression models, t tests, and Fisher's exact tests. RESULTS: Mean (SD) age was 61.6 (8.7) years, and 36.5% were men. Ethnicity of the patients included Hispanic (44.5%), African American (27.9%), Asian (14.1%), and White (12.9%). Pathway and nonpathway patients were similar demographically and racially. Pathway patients had shorter LOS (P = .04), less PCA use (P < .001), more frequent discharge home (P = .03), fewer transfusions (P = .002), and higher postoperative hemoglobin (P < .001). Overall incidence of complications was similar (P = .61). Nonpathway patients developed more cardiopulmonary complications (P = .02), whereas pathway patients had more wound dehiscence (P = .01). CONCLUSIONS: Compared with nonpathway patients, standardized TKA pathway patients had shorter LOS, decreased PCA use, increased discharge to home, fewer blood transfusions, and higher postoperative hemoglobin, with no difference in total incidence of complication.

Thirty-day readmissions and reoperations after total elbow arthroplasty: a national database study.

BACKGROUND: The purpose of this study was to determine the rate of short-term complications after total elbow arthroplasty (TEA) and identify predictors of readmission and reoperation. We hypothesized that TEA performed for acute elbow trauma would have higher rates of 30-day readmission and reoperation than TEA performed for osteoarthritis (OA). METHODS: Using the National Surgical Quality Improvement Program for the years 2011-2017, we identified patients undergoing TEA for fracture, OA, or inflammatory arthritis. Patient demographic characteristics, comorbidities, reoperations, and readmissions within 30 days of surgery were analyzed. Potential predictors of reoperation and readmission in the model included age, sex, race, body mass index (BMI), diabetes, hypertension, chronic obstructive pulmonary disease, congestive heart failure, smoking, bleeding disorders, American Society of Anesthesiologists classification, wound classification, operative time, and indication for surgery. RESULTS: A total of 414 patients underwent TEA from 2011-2017. Of these patients, 40.6% underwent TEA for fracture; 37.0%, for OA; and 22.7%, for inflammatory arthritis. The overall rate of unplanned readmissions was 5.1% (21 patients). The rate of unplanned reoperations was 2.4% (10 patients). Infection was the most common reason for both unplanned readmissions and reoperations. The rates of reoperations and readmissions were not significantly associated with any of the 3 operative indications: fracture, OA, or inflammatory arthritis. Multiple logistic regression analysis found increased BMI to be associated with lower odds of an unplanned readmission (odds ratio [OR], 0.883; 95% confidence interval [CI], 0.798-0.963; P = .0035) and found wound classification ≥ 3 to be associated with increased odds of an unplanned reoperation (OR, 16.531; 95% CI, 1.300-167.960; P = .0144) and total local complications (OR, 17.587; 95% CI, 2.207-132.019; P = .0057). Patients who were not functionally independent were more likely to experience local complications (OR, 4.181; 95% CI, 0.983-15.664; P = .0309) than were functionally independent patients. CONCLUSIONS: The 30-day unplanned reoperation rate after TEA was 2.4%, and the unplanned readmission rate was 5.1%. Low BMI was predictive of readmission. Wounds classified as contaminated or dirty were predictive of reoperation. Dependent functional status and contaminated wounds were predictive of local complications. The indication for TEA (fracture vs. OA vs. inflammatory arthritis) was not found to be a risk factor for reoperation or readmission after TEA.

Surgically relevant anatomy of the axillary and radial nerves in relation to the latissimus dorsi tendon in variable shoulder positions: A cadaveric study.

BACKGROUND: The purpose of this study was to define the relationship of the axillary and radial nerves, particularly how these are affected with changing arm position. METHODS: Twenty cadaveric shoulders were dissected, identifying the axillary and radial nerves. Distances between the latissimus dorsi tendon and these nerves were recorded in different shoulder positions. Positions included adduction/neutral rotation, abduction/neutral rotation for the axillary nerve, adduction/internal rotation, adduction/neutral rotation, adduction/external rotation, and abduction/external rotation for the radial nerve. RESULTS: Width of the latissimus tendon at its humeral insertion was 29.3 ± 5.7 mm. Mean distance from the latissimus insertion to the axillary nerve in adduction/neutral rotation was 24.2 ± 7.1 mm, the distance increased to 41.1 ± 9.8 mm in abduction/neutral rotation. Mean distance from the latissimus insertion to the radial nerve was 15.3 ± 5.5 mm with adduction/internal rotation, 25.8 ± 6.9 mm in adduction/neutral rotation, and 39.5 ± 6.8 mm in adduction/external rotation. Mean distance increased with abduction/external rotated 51.1 ± 7.4 mm. CONCLUSIONS: Knowing the axillary and radial nerve locations relative to the latissimus dorsi tendon decreases the risk of iatrogenic nerve injury. Understanding the dynamic nature of these nerves related to different shoulder positions is critical to avoid complications.

Innervation of the subscapularis: an anatomic study.

BACKGROUND: Successful healing of the subscapularis during anatomic total shoulder arthroplasty surgery is critical to optimize functional outcomes and avoid complications. The purpose of this study was to examine the upper and lower subscapularis nerve insertion in relation to the musculotendinous junction to estimate the risk of nerve injury. Our hypothesis was that arm position changes the risks to these nerves when exposing the anterior glenoid. METHODS: Twenty cadaveric shoulders were dissected, and the subscapular nerves were identified from the posterior cord of the brachial plexus to the muscle insertion. The nerve length from the origin to the muscle insertion and the distance to the myotendinous junction were measured in various shoulder positions including neutral, external, and internal rotation. RESULTS: The mean length of the upper subscapular nerve was 51.4 ± 12.8 mm; that of the lower subscapular nerve was 50.5 ± 14 mm. The mean distance from the insertion of the upper subscapular nerve to the myotendinous junction 53.0 ± 14.7 mm with external rotation, 38.5 ± 9.7 mm with neutral rotation, and 30.0 ± 9.2 mm with internal rotation. The mean distance from the lower subscapular nerve to the myotendinous junction was 44.5 ± 13.8 mm with external rotation, 31.9 ± 9.3 mm with neutral rotation, and 25.4 ± 8.8 mm with internal rotation. The internally rotated position placed these nerves closest to the glenohumeral joint. CONCLUSION: The upper and lower subscapular nerves insert in the muscle belly close to the myotendinous junction, putting them at risk of iatrogenic injury. Care must be taken to avoid damage with retractor placement in the anterior glenoid neck as these nerves are at risk of compression or torsional injury.

Prevalence of Central Nervous System Polypharmacy and Associations with Overdose and Suicide-Related Behaviors in Iraq and Afghanistan War Veterans in VA Care 2010-2011.

BACKGROUND: The increase in the quantities of central nervous system (CNS)-acting medications prescribed has coincided with increases in overdose mortality, suicide-related behaviors, and unintentional deaths in military personnel deployed in support of the wars in Iraq and Afghanistan. Data on the extent and impact of prescribing multiple CNS drugs among Iraq and Afghanistan Veterans (IAVs) are sparse. OBJECTIVES: We sought to identify the characteristics of IAVs with CNS polypharmacy and examine the association of CNS polypharmacy with drug overdose and suicide-related behaviors controlling for known risk factors. METHODS: This cross-sectional cohort study examined national data of Iraq and Afghanistan Veterans (N = 311,400) who used the Veterans Health Administration (VHA) during the fiscal year 2011. CNS polypharmacy was defined as five or more CNS-acting medications; drug/alcohol overdose and suicide-related behaviors were identified using ICD-9-CM codes. Demographic and clinical characteristics associated with CNS polypharmacy were identified using a multivariable logistic regression model. RESULTS: We found that 25,546 (8.4 %) of Iraq and Afghanistan Veterans had CNS polypharmacy. Those with only post-traumatic stress disorder (PTSD) (adjusted odds ratio (AOR) 6.50, 99 % confidence interval (CI) 5.96-7.10), only depression (AOR 6.42, 99 % CI 5.86-7.04), co-morbid PTSD and depression (AOR 12.98, 99 % CI 11.97-14.07), and co-morbid traumatic brain injury (TBI), PTSD, and depression (AOR 15.30, 99 % CI 14.00-16.73) had the highest odds of CNS polypharmacy. After controlling for these co-morbid conditions, CNS polypharmacy was significantly associated with drug/alcohol overdose and suicide-related behavior. CONCLUSION: CNS polypharmacy was most strongly associated with PTSD, depression, and TBI, and independently associated with overdose and suicide-related behavior after controlling for known risk factors. These findings suggest that CNS polypharmacy may be used as an indicator of risk for adverse outcomes. Further research should evaluate whether CNS polypharmacy may be used as a trigger for evaluation of the current care provided to these individuals.

Crystal structure of human Karyopherin ß2 bound to the PY-NLS of Saccharomyces cerevisiae Nab2.

Import-Karyopherin or Importin proteins bind nuclear localization signals (NLSs) to mediate the import of proteins into the cell nucleus. Karyopherin ß2 or Kapß2, also known as Transportin, is a member of this transporter family responsible for the import of numerous RNA binding proteins. Kapß2 recognizes a targeting signal termed the PY-NLS that lies within its cargos to target them through the nuclear pore complex. The recognition of PY-NLS by Kapß2 is conserved throughout eukaryotes. Kap104, the Kapß2 homolog in Saccharomyces cerevisiae, recognizes PY-NLSs in cargos Nab2, Hrp1, and Tfg2. We have determined the crystal structure of Kapß2 bound to the PY-NLS of the mRNA processing protein Nab2 at 3.05-Å resolution. A seven-residue segment of the PY-NLS of Nab2 is observed to bind Kapß2 in an extended conformation and occupies the same PY-NLS binding site observed in other Kapß2·PY-NLS structures.

Sequence and structural analyses of nuclear export signals in the NESdb database.

We compiled >200 nuclear export signal (NES)-containing CRM1 cargoes in a database named NESdb. We analyzed the sequences and three-dimensional structures of natural, experimentally identified NESs and of false-positive NESs that were generated from the database in order to identify properties that might distinguish the two groups of sequences. Analyses of amino acid frequencies, sequence logos, and agreement with existing NES consensus sequences revealed strong preferences for the Φ1-X(3)-Φ2-X(2)-Φ3-X-Φ4 pattern and for negatively charged amino acids in the nonhydrophobic positions of experimentally identified NESs but not of false positives. Strong preferences against certain hydrophobic amino acids in the hydrophobic positions were also revealed. These findings led to a new and more precise NES consensus. More important, three-dimensional structures are now available for 68 NESs within 56 different cargo proteins. Analyses of these structures showed that experimentally identified NESs are more likely than the false positives to adopt α-helical conformations that transition to loops at their C-termini and more likely to be surface accessible within their protein domains or be present in disordered or unobserved parts of the structures. Such distinguishing features for real NESs might be useful in future NES prediction efforts. Finally, we also tested CRM1-binding of 40 NESs that were found in the 56 structures. We found that 16 of the NES peptides did not bind CRM1, hence illustrating how NESs are easily misidentified.