International Delphi Study on Wound Closure and Dressing Management in Joint Arthroplasty: Part 1: Total Knee Arthroplasty.

BACKGROUND: The purpose of this modified Delphi study was to obtain consensus on wound closure and dressing management in total knee arthroplasty (TKA). METHODS: The Delphi panel included 20 orthopaedic surgeons from Europe and North America. There were 26 statements identified using a targeted literature review. Consensus was developed for the statements with up to three rounds of anonymous voting per topic. Panelists ranked their agreement with each statement on a five-point Likert scale. An a priori threshold of ≥ 75% was required for consensus. RESULTS: All 26 statements achieved consensus after three rounds of anonymous voting. Wound closure-related interventions that were recommended for use in TKA included: 1) closing in semi-flexion versus extension (superior range of motion); 2) using aspirin for venous thromboembolism prophylaxis over other agents (reduces wound complications); 3) barbed sutures over non-barbed sutures (lower wound complications, better cosmetic appearances, shorter closing times, and overall cost savings); 4) mesh-adhesives over other skin closure methods (lower wound complications, higher patient satisfaction scores, lower rates of readmission); 5) silver-impregnated dressings over standard dressings (lower wound complications, decreased infections, fewer dressing changes); 6) in high-risk patients, negative pressure wound therapy over other dressings (lower wound complications, decreased reoperations, fewer dressing changes); and 7) using triclosan-coated over non-antimicrobial-coated sutures (lower risks of surgical site infection). CONCLUSIONS: Using a modified Delphi approach, the panel achieved consensus on 26 statements pertaining to wound closure and dressing management in TKA. This study forms the basis for identifying critical evidence supported by clinical practice for wound management to help reduce variability, advance standardization, and ultimately improve outcomes during TKA. The results presented here can serve as the foundation for knowledge, education, and improved clinical outcomes for surgeons performing TKAs.

International Delphi Study on Wound Closure and Incision Management in Joint Arthroplasty Part 2: Total Hip Arthroplasty.

BACKGROUND: This modified Delphi study aimed to develop a consensus on optimal wound closure and incision management strategies for total hip arthroplasty (THA). Given the critical nature of wound care and incision management in influencing patient outcomes, this study sought to synthesize evidence-based best practices for wound care in THA procedures. METHODS: An international panel of 20 orthopedic surgeons from Europe, Canada, and the United States evaluated a targeted literature review of 18 statements (14 specific to THA and 4 related to both THA and total knee arthroplasty). There were 3 rounds of anonymous voting per topic using a modified 5-point Likert scale with a predetermined consensus threshold of ≥ 75% agreement necessary for a statement to be accepted. RESULTS: After 3 rounds of voting, consensus was achieved for all 18 statements. Notable recommendations for THA wound management included (1) the use of barbed sutures over non-barbed sutures (shorter closing times and overall cost savings); (2) the use of subcuticular sutures over skin staples (lower risk of superficial infections and higher patient preferences, but longer closing times); (3) the use of mesh-adhesives over silver-impregnated dressings (lower rate of wound complications); (4) for at-risk patients, the use of negative pressure wound therapy over other dressings (lower wound complications and reoperations, as well as fewer dressing changes); and (5) the use of triclosan-coated sutures (lower risk of surgical site infection) over standard sutures. CONCLUSIONS: Through a structured modified Delphi approach, a panel of 20 orthopedic surgeons reached consensus on all 18 statements pertaining to wound closure and incision management in THA. This study provides a foundational framework for establishing evidence-based best practices, aiming to reduce variability in patient outcomes and to enhance the overall quality of care in THA procedures.

Use of interrupted time-series analyses in evaluating health economic outcomes following implementation of multilayer water-tight wound closure in a primary total joint arthroplasty population.

Aim: Total joint arthroplasty (TJA) with multi-layer, watertight closure (MLWC) using knotless barbed suture and 2-octyl cyanoacrylate plus polymer mesh tape was compared with conventional closure (CC) using Vicryl™ sutures and staples. Patients & methods: Electronic medical records of patients undergoing TJA (1574: total knee arthroplasty; 580: total hip arthroplasty; 13: unknown) from a single surgeon at a US hospital (CC 2011 to 2013; MLWC 2015 to 2020) were reviewed. Outcomes were length of stay (LOS), discharge to skilled nursing facility (SNF), 90-day surgical site infection (SSI) and 90-day readmission. Logistic regression controlled for baseline characteristics. Adjusted interrupted time series (ITS) analyses accounted for decreasing trends in LOS and SNF discharge over time. Results: Among 2167 TJA cases (mean [standard deviation] age 66.0 [9.7] years, 53.3% female), 906 received CC and 1261 received MLWC. Bivariate analysis showed no statistically significant differences in 90-day SSI rates; however, MLWC patients had 60% lower 90-day readmission rates (1.5 vs 3.8%, p < 0.05), 44% lower LOS (1.4 vs 2.5 days, p < 0.05) and 40% lower discharge rates to a skilled care facility (8.5 vs 14.1%, p < 0.05). Multivariable analyses showed CC patients were 2.45-times more likely to be readmitted within 90 days, 1.88-times more likely to be discharged to SNF and had 1.67-times longer LOS compared with MLWC. ITS analyses showed a sharp decline in LOS (0.9 days) and discharge to SNF (5.6% incidence) after implementation of MLWC, followed by no further changes for the remainder of the study period. Conclusion: MLWC was associated with ≥40% reduction in 90-day readmission, LOS and SNF discharge compared with TJA CC. LOS and discharge rate to SNF declined sharply after the implementation of MLWC.

Longitudinal rates, risk factors, and costs of superficial and deep incisional surgical-site infection (SSI) after primary and revision total knee arthroplasty: A US retrospective claims database analysis.

OBJECTIVE: We evaluated longitudinal rates, risk factors, and costs of superficial and deep incisional surgical-site infection (SSI) 6 months after primary total knee arthroplasty (pTKA) and revision total knee arthroplasty (rTKA). METHODS: Patients were identified from January 1, 2016 through March 31, 2018, in the IBM MarketScan administrative claims databases. Kaplan-Meier survival curves evaluated time to SSI over 6 months. Cox proportional hazard models evaluated SSI risk factors. Generalized linear models estimated SSI costs up to 12 months. RESULTS: Of the 26,097 pTKA patients analyzed (mean age, 61.6 years; SD, 9.2; 61.4% female; 60.4% commercial insurance), 0.65% (95% CI, 0.56%-0.75%) presented with a deep incisional SSI and 0.82% (95% CI, 0.71%-0.93%) with a superficial incisional SSI. Also, 3,663 patients who had rTKA (mean age, 60.9 years; SD, 10.1; 60.6% female; 53.0% commercial insurance), 10.44% (95% CI, 9.36%-11.51%) presented with a deep incisional SSI and 2.60% (95% CI, 2.07%-3.13%) presented with a superficial incisional SSI. Infections were associated with male sex and multiple patient comorbidities including chronic pulmonary disease, pulmonary circulatory disorders, fluid and electrolyte disorders, malnutrition, drug abuse, and depression. Adjusted average all-cause incremental commercial cost ranged from $14,298 to $29,176 and from $41,381 to 59,491 for superficial and deep incisional SSI, respectively. CONCLUSIONS: SSI occurred most frequently following rTKA and among patients with pulmonary comorbidities and depression. The incremental costs associated with SSI following TKA were substantial.

Longitudinal Rates, Patient Risk Factors, and Economic Impact of Superficial and Deep Incisional Surgical Site Infection After Primary and Revision Total Hip Arthroplasty: A U.S. Retrospective Commercial Claims Database Analysis.

Background: Longitudinal rates, risk factors, and costs of superficial and deep incisional surgical site infection (SSI) were evaluated six months after primary total hip arthroplasty (pTHA) and revision total hip replacement (rTHA). Patients and Methods: Patients who had pTHA or rTHA between January 1, 2016 and March 31, 2018 were identified using the IBM® MarketScan® administrative claims databases. Kaplan-Meier survival curves evaluated time to SSI over six months. Cox proportional hazard models evaluated SSI risk factors. Generalized linear models estimated SSI costs up to 12 months. Results: The total cohort included 17,514 pTHA patients (mean [standard deviation] age 59.6 [10.1] years, 50.2% female; 66.4% commercial insurance), and 2,954 rTHA patients (61.2 [12.0] years, 52.0% female; 48.6% commercial insurance). Deep and superficial post-operative SSI at six months affected 0.30% (95% confidence interval [CI], 0.22%-0.39%) and 0.67% (95% CI, 0.55%-0.79% of patients in the pTHA, and 8.9% (95%CI: 7.8%-10.0%) and 4.8% (95% CI, 4.0%-5.6%) of patients in the rTHA cohorts. Hazards for SSI were related to patient comorbidities that included diabetes mellitus, obesity, renal failure, pulmonary or circulatory disorders, and depression. The adjusted average all-cause incremental commercial costs associated with post-operative infection ranged from $21,434 to $42,879 for superficial incisional SSI and $53,884 to $76,472 for deep incisional SSI, over a 12-month post-operative assessment period. Conclusions: The SSI rate after revision total hip arthroplasty (rTHA) was nearly 9% compared with 1.0% after pTHA. The risk of infection was influenced by several comorbid risk factors. The incremental cost associated with SSIs was substantial.

Effects of co-cultures of meniscus cells and articular chondrocytes on PLLA scaffolds.

The knee meniscus, a fibrocartilaginous tissue located in the knee joint, is characterized by heterogeneity in extracellular matrix and biomechanical properties. To recreate these properties using a tissue engineering approach, co-cultures of meniscus cells (MCs) and articular chondrocytes (ACs) were seeded in varying ratios (100:0, 75:25, 50:50, 25:75, and 0:100) on poly-L-lactic acid (PLLA) scaffolds and cultured in serum-free medium for 4 weeks. Histological, biochemical, and biomechanical tests were used to assess constructs at the end time point. Strong staining for collagen and glycosaminoglycan (GAG) was observed in all groups. Constructs with 100% MCs were positive for collagen I and constructs cultured with 100% ACs were positive for collagen II, while a mixture of collagen I and II was observed in other co-culture groups. Total collagen and GAG per construct increased as the percentage of ACs increased (27 +/- 8 microg, 0% AC to 45 +/- 8 microg, 100% ACs for collagen and 12 +/- 4 microg, 0% ACs to 40 +/- 5 microg, 100% ACs for GAG). Compressive modulus (instantaneous and relaxation modulus) of the constructs was significantly higher in the 100% ACs group (63 +/- 12 and 22 +/- 9 kPa, respectively) when compared to groups with higher percentage of MCs. No differences in tensile properties were noted among groups. Specific co-culture ratios were identified mimicking the GAG/DW of the inner (0:100, 25:75, and 50:50) and outer regions (100:0) of the meniscus. Overall, it was demonstrated that co-culturing MCs and ACs on PLLA scaffolds results in functional tissue engineered meniscus constructs with a spectrum of biochemical and biomechanical properties.

Migration responses of outer and inner meniscus cells to applied direct current electric fields.

Injuries to the inner regions of the knee meniscus do not heal and can result in degenerative changes to the articular surface, ultimately leading to osteoarthritis. A possible stimulus to enhance meniscus healing is to use electric fields that induce galvanotaxis. In this study, a novel characterization of the effects of direct current electric fields on migration characteristics of meniscus cells was performed. Primary and passaged inner and outer meniscus cells were exposed to varying electric field strengths from 0 to 6 V/cm. Cell migration was tracked using time lapse digital photography, and cell displacement and cathodal direct velocity were quantified. Cytoskeletal staining was performed to examine actin distribution and nuclear content. Cell adhesion strength was quantified as a function of wall shear stress. Meniscus cells exhibited cathodal migration and cell elongation perpendicular to the applied electric field accompanied by actin reorganization. Outer meniscus cells migrated quicker and exhibited lower adhesion strengths when compared to inner meniscus cells. Passaged cells exhibited higher migration characteristics when compared to primary cells. Overall, this study demonstrated that electric fields can significantly enhance and direct meniscus cell migration and suggests the potential for their incorporation in strategies of meniscus repair and tissue engineering.

Additive and synergistic effects of bFGF and hypoxia on leporine meniscus cell-seeded PLLA scaffolds.

Injuries to avascular regions of menisci do not heal and result in significant discomfort to patients. Current treatments, such as partial meniscectomy, alleviate these symptoms in the short term but lead to premature osteoarthritis as a result of compromised stability and changes in knee biomechanics. Thus, tissue engineering of the meniscus may provide an alternative treatment modality to overcome this problem. In this experiment, a scaffold-based tissue-engineering approach was utilized to regenerate the meniscus. Meniscus cells were cultured on poly-L-lactic acid scaffolds in normoxic (approximately 21% oxygen) or hypoxic (approximately 2% oxygen) conditions in the presence or absence of the growth factor, basic fibroblast growth factor (bFGF). At t = 4 weeks, histological sections of constructs showed presence of collagen and glycosaminoglycan (GAG) in all groups. Immunohistochemical staining showed the presence of collagen I in all groups and collagen II in groups cultured under hypoxic conditions. bFGF in the culture medium significantly increased cell number/construct by 25%, regardless of culture conditions. For GAG/construct, synergistic increases were observed in constructs cultured in hypoxic conditions and bFGF (two-fold) when compared to constructs cultured in normoxic conditions. Compressive tests showed synergistic increases in the relaxation modulus and coefficient of viscosity and additive increases in the instantaneous modulus for constructs cultured under hypoxic conditions and bFGF, when compared to constructs cultured under normoxic conditions. Overall, these results demonstrate that bFGF and hypoxia can significantly enhance the ability of meniscus cells to produce GAGs and improve the compressive properties of tissue-engineered meniscus constructs in vitro.

Effects of hydrostatic pressure on leporine meniscus cell-seeded PLLA scaffolds.

Hydrostatic pressure (HP) is an important component of the loading environment of the knee joint. Studies with articular chondrocytes and TMJ disc fibrochondrocytes have identified certain benefits of HP for tissue engineering purposes. However, similar studies with meniscus cells are lacking. Thus, in this experiment, the effects of applying 10 MPa of HP at three different frequencies (0, 0.1, and 1 Hz) to leporine meniscus cell-seeded PLLA scaffolds were examined. HP was applied once every 3 days for 1 h for a period of 28 days. Constructs were analyzed for cellular, biochemical, and biomechanical properties. At t = 4 weeks, total collagen/scaffold was found to be significantly higher in the 10 MPa, 0 Hz group when compared with other groups. This despite the fact that the cell numbers/scaffold were found to be lower in all HP groups when compared with the culture control. Additionally, the total GAG/scaffold, instantaneous modulus, and relaxation modulus were significantly increased in the 10 MPa, 0 Hz group when compared with the culture control. In summary, this experiment provides evidence for the benefit of a 10 MPa, 0 Hz stimulus, on both biochemical and biomechanical aspects, for the purposes of meniscus tissue engineering using PLLA scaffolds.

Effects of TGF-beta1 and hydrostatic pressure on meniscus cell-seeded scaffolds.

The combinatorial effects of TGF-beta1 and hydrostatic pressure (HP) were investigated on meniscus cell-seeded PLLA constructs using a two-phase sequential study. The objective was to identify potentially synergistic effects of these stimuli toward enhancing the biomechanical and compositional characteristics of the engineered constructs. In Phase I, the effects of TGF-beta1 were examined on the ability of meniscus cells to produce ECM. In Phase II, meniscus cell-seeded PLLA constructs were cultured for 4 wks with a combination of TGF-beta1 and HP (10 MPa, 0 Hz or 10 MPa, 0.1 Hz). TGF-beta1 was found to increase collagen and GAG deposition in the scaffolds 15-fold and 8-fold, respectively, in Phase I. In Phase II, the combination of TGF-beta1 and 10 MPa, 0 Hz HP resulted in 4-fold higher collagen deposition (additive increase), 3-fold higher GAG deposition and enhanced compressive properties (additive and synergistic increases), when compared to the unpressurized no growth factor culture control. Though significant correlations were observed between the compressive properties (moduli and viscosity), and the GAG and collagen content of the constructs, the correlations were stronger with collagen. This study provides robust evidence that growth factors and HP can be used successfully in combination to enhance the functional properties of in vitro engineered knee meniscus constructs.

Effects of agarose mould compliance and surface roughness on self-assembled meniscus-shaped constructs.

The meniscus is a fibrocartilaginous tissue that is critically important to the loading patterns within the knee joint. If the meniscus structure is compromised, there is little chance of healing, due to limited vascularity in the inner portions of the tissue. Several tissue-engineering techniques to mimic the complex geometry of the meniscus have been employed. Of these, a self-assembly, scaffoldless approach employing agarose moulds avoids drawbacks associated with scaffold use, while still allowing the formation of robust tissue. In this experiment two factors were examined, agarose percentage and mould surface roughness, in an effort to consistently obtain constructs with adequate geometric properties. Co-cultures of ACs and MCs (50:50 ratio) were cultured in smooth or rough moulds composed of 1% or 2% agarose for 4 weeks. Morphological results showed that constructs formed in 1% agarose moulds, particularly smooth moulds, were able to maintain their shape over the 4 week culture period. Significant increases were observed for the collagen II:collagen I ratio, total collagen, GAG and tensile and compressive properties in smooth wells. Cell number per construct was higher in the rough wells. Overall, it was observed that the topology of an agarose surface may be able to affect the phenotypic properties of cells that are on that surface, with smooth surfaces supporting a more chondrocytic phenotype. In addition, wells made from 1% agarose were able to prevent construct buckling potentially, due to their higher compliance.

Passage and reversal effects on gene expression of bovine meniscal fibrochondrocytes.

The knee meniscus contains a mixed population of cells that exhibit fibroblastic as well as chondrocytic characteristics. Tissue engineering studies and future therapies for the meniscus require a large population of cells that are seeded on scaffolds. To achieve this, monolayer expansion is often used as a technique to increase cell number. However, the phenotype of these cells may be significantly different from that of the primary population. The objective of this study was to investigate changes in meniscal fibrochondrocytes at the gene expression level over four passages using quantitative real-time reverse transcriptase polymerase chain reaction. Cells from the inner two-thirds of bovine medial menisci were used. Four extracellular matrix (ECM) molecules, commonly found in the meniscus, were investigated, namely collagen I, collagen II, aggrecan and cartilage oligomeric matrix protein (COMP). In addition, primary and passaged meniscus fibrochondrocytes were placed on surfaces coated with collagen I or aggrecan protein to investigate whether any gene expression changes resulting from passage could be reversed. Collagen I expression was found to increase with the number of passages, whereas collagen II and COMP expression decreased. Collagen I and aggrecan surface coatings were shown to downregulate and upregulate collagen I and COMP expression levels, respectively, in passaged cells. However, decreases in collagen II expression could not be reversed by either protein coating. These results indicate that although monolayer expansion results in significant changes in gene expression in meniscal fibrochondrocytes, protein coatings may be used to regain the primary cell expression of several ECM molecules.

A mechanical study of rigid plate configurations for sternal fixation.

Rigid metal plates are a promising alternative to wires for reapproximating the sternum after open-heart surgery due to their potential ability to reduce motion at the wound site and thereby reduce the likelihood of post-operative healing complications. Despite initial clinical success, the use of plates has been limited, in part, by insufficient knowledge about their most effective placement. This study compares the ability of five plate configurations to provide stable closure by limiting sternal separation. Commercially available x-shaped and box-shaped plates were used and combinations of parameters (plate type, location, and number of plates) were investigated in vitro. Lateral distraction tests using controlled, uniform loading were conducted on 15 synthetic sterna and the distractions between separated sternum halves were measured at seven locations. Distractions at the xiphoid, a critical region clinically, varied widely from 0.03 +/- 0.53 mm to 4.24 +/- 1.26 mm depending on all three plate parameters. Of the configurations tested, three x-shaped plates and one box-shaped plate resisted sternal separation most effectively. These results provide the first comparison of plate configurations for stabilizing a sternotomy. However, basic mechanical analyses indicate that sternal loading in vivo is non-uniform; future studies will need to accurately quantify in vivo loading to improve in vitro test methods.

Biodegradable materials in arthroscopy.

The use of biodegradable materials as implants has revolutionized the way medicine is practiced today. This review provides a general description of salient biodegradable polymeric materials currently used in arthroscopy. These materials include polyglycolic acid, self-reinforced polyglycolic acid, poly-L-lactic acid, self-reinforced polylactic-L-acid, poly-D-L-lactic acid, copolymer of poly-D-L-lactic acid polyglycolic acid, and polyglyconate. The mechanical strength, degradation properties, and widespread use of these materials, especially in the knee and shoulder, are discussed individually. Also discussed are the relatively few complications that are related to these materials' arthroscopic use. Future directions in biodegradable materials, including smart polymers, are also considered. In the future, novel techniques to identify the ideal polymer for a particular application will need to be developed to minimize the risk for implant complications.

In vitro comparison of wire and plate fixation for midline sternotomies.

BACKGROUND: The incidence of severe sternal wound complications in high-risk cardiac patients presents a significant need for more stabile sternal fixation techniques after median sternotomy procedures. Rigid metal plates, a potential alternative to wire fixation, are thought to promote faster sternal healing by reducing motion at the wound site. The goal of this study was to compare the stability provided by commercially available sternal plates with standard wires using an in vitro model. METHODS: Lateral distraction tests were conducted on bisected polyurethane sternal models fixed with either a standard 7 wire configuration (n = 5) or a 3 plate configuration (n = 3). To assure controlled loading, the sternal models were attached to a computer-controlled test machine by a novel tethering system that distributes the total force (180N) equally to eight locations on the sternum. Stability was defined as the ability to restrict sternal separation at seven locations along the midline quantified using digital image analysis. RESULTS: Our results indicate that rigid plate fixation significantly reduced lateral motion relative to wire fixation. The lower sternal region most noticeably benefited from plate fixation as the splaying observed for wire fixation was reduced. CONCLUSIONS: Under these loading conditions, plating increased stability at the midline compared to wires; this increased stability may facilitate the recovery of high-risk patients undergoing cardiac operation. To enhance in vitro testing methods, future studies should incorporate additional in vivo loading conditions applied to the sternum. Alternate plating configurations should also be examined to further increase stability.