Faculty Bibliography

INTRODUCTION/BACKGROUND:Prosthetic joint infection continues to be a source of significant morbidity to patients and an economic burden to society as a whole. Two-stage revision is the current gold standard for treatment of periprosthetic joint infection in North America. Despite this, much discussion persists about treatment strategies surrounding the interim of the two-stage revision and treatment beyond reimplantation. The aim of this review is to answer some of these questions, specifically: are C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) helpful prior to reimplantation, is aspiration helpful, what is the role and timing for systemic antibiotics, and is there a role for oral suppression following second-stage reimplantation? METHODS:A literature review was completed in an attempt to address unanswered questions associated with two-stage reimplantation. Investigators' recommendations and current practices are described. RESULTS:ESR and CRP are less reliable in the interim of a two-stage revision than for diagnosis of infection in a primary total joint arthroplasty. There is inconclusive evidence regarding the utility of joint aspiration in two-stage revisions. Additionally, no evidence has been developed for length of IV antibiotic treatment after second-stage reimplantation, and in a few studies, oral antibiotic suppression has shown some benefit in reducing reinfection rates. CONCLUSION/CONCLUSIONS:The question of optimum treatment strategies has yet to be answered: attempts are underway to obtain suitable data with multi-center studies and large patient populations. Periprosthetic joint infection is a serious and life altering complication and with continued research we can further clarify treatment strategies.

Postoperative radiographs remain the standard for assessment of component placement following total hip arthroplasty (THA), despite the known limitations of radiographs. Computed tomography (CT) scanning offers improved accuracy, but its costs and radiation exposure are prohibitive. The authors performed a cadaver study to compare the error associated with radiographs with that of CT scans following THA. The authors also compared imaging with a novel mini-navigation system. Three board-certified orthopedic surgeons each performed 4 THA procedures (6 cadavers, 12 hips) via the posterior approach using a mini-navigation tool to assist with component placement. Cup position from imaging was compared with corrected CT values for anteversion and inclination, created by correcting the initial scan to align the anterior pelvic plane coplanar with the CT table, thus representing cup position not distorted by imaging or positioning. Anteversion from standard CT scans was within 2.5° (standard deviation [SD], 1.5°) of reference values (P=.25); radiographs showed an average error of 7.8° (SD, 4.3°) vs reference values (all values absolute means) (P<.01). The mini-navigation system provided anteversion values within an average of 4.0° (SD, 4.0°) of reference anteversion (P<.01). Standard CT values for inclination were within 2.4° (SD, 2.0°) of reference values (P=.53), whereas radiographic inclination values were within 2.5° (SD, 2.3°) (P=.12). Mini-navigation values for inclination were within 3.9° (SD, 3.2°) of reference inclination (P=.26). This study demonstrated that cup position as measured by radiographs is significantly less accurate than CT scans and that the mini-navigation system provided anteversion measurements that were of comparable accuracy to CT scans. [Orthopedics. 2017; 40(6):e952-e958.].

BACKGROUND:Atsttrin, an engineered protein composed of three tumor necrosis factor receptor (TNFR)-binding fragments of progranulin (PGRN), shows therapeutic effect in multiple murine models of inflammatory arthritis . Additionally, intra-articular delivery of PGRN protects against osteoarthritis (OA) progression. The purpose of this study is to determine whether Atsttrin also has therapeutic effects in OA and the molecular mechanisms involved. METHODS:Surgically induced and noninvasive rupture OA models were established in mouse and rat, respectively. Cartilage degradation and OA were evaluated using Safranin O staining, immunohistochemistry, and ELISA. Additionally, expressions of pain-related markers, degenerative factors, and anabolic and catabolic markers known to be involved in OA were analyzed. Furthermore, the anabolic and anti-catabolic effects and underlying mechanisms of Atsttrin were determined using in-vitro assays with primary chondrocytes. RESULTS:Herein, we found Atsttrin effectively prevented the accelerated OA phenotype associated with PGRN deficiency. Additionally, Atsttrin exhibited a preventative effect in OA by protecting articular cartilage and reducing OA-associated pain in both nonsurgically induced rat and surgically induced murine OA models. Mechanistic studies revealed that Atsttrin stimulated TNFR2-Akt-Erk1/2-dependent chondrocyte anabolism, while inhibiting TNFα/TNFR1-mediated inflammatory catabolism. CONCLUSIONS:These findings not only provide new insights into the role of PGRN and its derived engineered protein Atsttrin in cartilage homeostasis as well as OA in vivo, but may also lead to new therapeutic alternatives for OA as well as other relative degenerative joint diseases.

Background/UNASSIGNED:After home health care, the skilled nursing facility (SNF) is the most commonly used postacute care modality, among Medicare beneficiaries, after total joint arthroplasty. Prior studies demonstrated that a loss in postsurgical ambulatory gains is incurred in the interval between hospital discharge and arrival at the SNF. The aim of this present study is to determine the consequences of that loss in function, as well as compare SNF-related outcomes in patients with Medicare vs Managed Care (MC) insurance. Methods/UNASSIGNED:We conducted a retrospective analysis of 80 patients (54 Medicare and 26 MC) who attended an SNF after hospitalization for total joint arthroplasty. Outcomes from physical therapy records were abstracted from each patient's SNF file. Results/UNASSIGNED:There was an approximately 40% drop-off in gait achievements between hospital discharge and SNF admission. This decline in ambulation was significantly greater in Medicare patients (Medicare: 94.6 ± 123.2 ft, MC: 40.0 ± 48.9 ft, P = .034). Larger reductions in gait achievements between hospital discharge and SNF admission were significantly correlated with longer SNF lengths of stay and poorer gait achievements by SNF discharge. Patients with MC insurance made significant improvements in gait training at the SNF beyond that which was acquired at the hospital, whereas Medicare patients did not (PMedicare  = .28, PMC  = .003). Conclusions/UNASSIGNED:Large losses in motor function between hospital discharge and SNF admission were associated with poor functional outcomes and longer stays at the SNF. These effects were more pronounced in Medicare patients than those with MC insurance.

Background/UNASSIGNED:Implant price has been identified as a significant contributing factor to high costs associated with revision total knee arthroplasty (rTKA). The goal of this study is to analyze the cost of implants used in rTKAs and to compare this pricing with 2 alternative pricing models. Methods/UNASSIGNED:Using our institutional database, we identified 52 patients from January 1, 2014 to December 31, 2014. Average cost of components for each case was calculated and compared to the total hospital cost for that admission. Costs for an all-component revision were then compared to a proposed "direct to hospital" (DTH) standardized pricing model and a fixed price revision option. Potential savings were calculated from these figures. Results/UNASSIGNED:On average, 28% of the total hospital cost was spent on implants for rTKA. The average cost for revision of all components was $13,640 and ranged from $3000 to $28,000. On average, this represented 32.7% of the total hospital cost. Direct to hospital implant pricing could potentially save approximately $7000 per rTKA, and the fixed pricing model could provide a further $1000 reduction per rTKA-potentially saving $8000 per case on implants alone. Conclusions/UNASSIGNED:Alternative implant pricing models could help lower the total cost of rTKA, which would allow hospitals to achieve significant cost containment.

Declining total joint arthroplasty reimbursement and rising implant prices have led many hospitals to restrict access to newer, more expensive total joint arthroplasty implants. The authors sought to understand arthroplasty surgeons' perspectives on implants regarding innovation, product launch, costs, and cost-containment strategies including surgeon gain-sharing and patient cost-sharing. Members of the International Congress for Joint Reconstruction were surveyed regarding attitudes about implant technology and costs. Descriptive and univariate analyses were performed. A total of 126 surgeons responded from all 5 regions of the United States. Although 76.9% believed new products advance technology in orthopedics, most (66.7%) supported informing patients that new implants lack long-term clinical data and restricting new implants to a small number of investigators prior to widespread market launch. The survey revealed that 66.7% would forgo gain-sharing incentives in exchange for more freedom to choose implants. Further, 76.9% believed that patients should be allowed to pay incremental costs for "premium" implants. Surgeons who believed that premium products advance orthopedic technology were more willing to forgo gain-sharing (P=.040). Surgeons with higher surgical volume (P=.007), those who believed implant companies should be allowed to charge more for new technology (P<.001), and those who supported discussing costs with patients (P=.004) were more supportive of patient cost-sharing. Most arthroplasty surgeons believe technological innovation advances the field but support discussing the "unproven" nature of new implants with patients. Many surgeons support alternative payment models permitting surgeons and patients to retain implant selection autonomy. Most respondents prioritized patient beneficence and surgeon autonomy above personal financial gain. [Orthopedics. 2017; 40(5):e825-e830.].

BACKGROUND: Pain catastrophizing has been suggested as a prospective risk factor for poor postoperative pain outcomes in total joint arthroplasty (TJA). However, results from the previous studies have been mixed and have not controlled for postoperative opiate analgesic intake. This study investigates pain catastrophizing and postoperative pain intensity in TJA patients, adjusting for analgesic intake. We hypothesized that "pain catastrophizers" would exhibit higher pain scores and increased analgesic requirements postoperatively. METHODS: In this prospective cohort study, patients were defined as catastrophizers (PCS > 30), or non-catastrophizers (PCS /= 3 postoperative days differed in VAS pain scores ("non-catastrophizers" = 5.08 vs. "catastrophizers" = 7.13; p = 0.002) and were 2.4 times more likely to be catastrophizers than non-catastrophizers (p = 0.042). There were no differences in the remaining secondary outcomes. CONCLUSION: The pain catastrophizing scale is a poor predictor of postoperative pain at 3-month follow-up. However, it may be a risk factor for increased LOS.

BACKGROUND: Short-term and intermediate-term wear rates for highly cross-linked polyethylene (HCLPE) liners in total hip arthroplasty (THA) are significantly lower than published rates for traditional polyethylene liners. The aim of this study was to report the longest-to-date follow-up of a specific HCLPE liner. METHODS: A series of 35 THAs using a specific HCLPE liner were reviewed. Anteroposterior radiographs were reviewed for femoral head penetration, the presence of femoral and/or acetabular osteolysis, long-term survival, total wear, and wear rates in all patients. RESULTS: The average patient age at time of surgery was 70 years with an average follow-up of 10 years (118 months; range, 7.2-13.4 years). The mean wear rate in our cohort was 0.07 mm/y. Total wear was 0.71 mm over the study period. No hips showed evidence of osteolysis in any zones. Survivorship at latest follow-up was 100% with all-cause revision as an end point. CONCLUSION: The wear rate of HCLPE liners continues to be lower than published wear rates for traditional polyethylene and continues to reaffirm the acceptably low wear rates using HCLPE acetabular liner in primary THA.

BACKGROUND: Although HbA1c is commonly used for assessing glycemic control before surgery, there is no consensus regarding its role and the appropriate threshold in predicting adverse outcomes. This study was designed to evaluate the potential link between HbA1c and subsequent periprosthetic joint infection (PJI), with the intention of determining the optimal threshold for HbA1c. METHODS: This is a multicenter retrospective study, which identified 1645 diabetic patients who underwent primary total joint arthroplasty (1004 knees and 641 hips) between 2001 and 2015. All patients had an HbA1c measured within 3 months of surgery. The primary outcome of interest was a PJI at 1 year based on the Musculoskeletal Infection Society criteria. Secondary outcomes included orthopedic (wound and mechanical complications) and nonorthopedic complications (sepsis, thromboembolism, genitourinary, and cardiovascular complications). A regression analysis was performed to determine the independent influence of HbA1c for predicting PJI. RESULTS: Overall 22 cases of PJI occurred at 1 year (1.3%). HbA1c at a threshold of 7.7 was distinct for predicting PJI (area under the curve, 0.65; 95% confidence interval, 0.51-0.78). Using this threshold, PJI rates increased from 0.8% (11 of 1441) to 5.4% (11 of 204). In the stepwise logistic regression analysis, PJI remained the only variable associated with higher HbA1c (odds ratio, 1.5; confidence interval, 1.2-2.0; P = .0001). There was no association between high HbA1c levels and other complications assessed. CONCLUSION: High HbA1c levels are associated with an increased risk for PJI. A threshold of 7.7% seems to be more indicative of infection than the commonly used 7% and should perhaps be the goal in preoperative patient optimization.