Recurrent Hemarthrosis After Total Knee Arthroplasty: Evaluation and Treatment.

Recurrent hemarthrosis (RH) is a rare complication (∼1%) after total knee arthroplasty (TKA). It is a complex and particularly frustrating problem for both patient and surgeon. Typically, patients present several months to years after their index TKA surgery with a painful and swollen joint. Although conservative management may provide temporary relief, the rate of recurrence is high. Despite extensive case series in the literature, no consensus was made on the criteria needed to establish this diagnosis, or how to best provide treatment. Several management strategies have been described for RH, including immobilization, arthroscopic versus open synovectomy, angiographic embolization, and revision arthroplasty. All of these have demonstrated variable effectiveness, with limited evidence for their use in specific situations. This review synthesizes the available literature and suggests an algorithm for the diagnosis and treatment of RH after TKA.

In vitro susceptibility of Propionibacterium acnes to simulated intrawound vancomycin concentrations.

BACKGROUND: There is convincing evidence supporting the prophylactic use of intrawound vancomycin powder in spinal fusion surgery and mounting evidence in the arthroplasty literature suggesting that it can reduce surgical site infections. As a result, a number of shoulder arthroplasty surgeons have adopted this practice, despite a paucity of evidence and the presence of a pathogen that is, for the most part, unique to this area of the body-Propionibacterium acnes. The purpose of this study was to evaluate the efficacy of vancomycin against planktonic P. acnes in vitro, using time-dependent concentrations one would expect in vivo after intra-articular application. METHODS: Intrawound vancomycin concentrations were interpolated and extrapolated from existing in vivo data. Planktonic P. acnes was then subjected to a time-kill analysis during 96 hours. At each time point, the inoculum was centrifuged into pellet form and then reconstituted for serial drop counts onto blood agar plates. After anaerobic incubation, colony-forming units were counted, and log10 colony-forming units per milliliter were determined. RESULTS: Early time points grew to confluence, and thus colony-forming units per milliliter were not calculated. However, at 12 hours of vancomycin treatment, distinct colonies were appreciated. Notably, there was a 3 × log10 reduction in colony-forming units per milliliter between 12 and 48 hours, denoting bactericidal activity. In addition, P. acnes was completely eradicated after 3 days of treatment. CONCLUSION: When administered in a fashion meant to simulate time-dependent in vivo intrawound concentrations, vancomycin exhibited bactericidal activity against P. acnes. This may lend credence to the prophylactic use of vancomycin in shoulder surgery.

Antimicrobial distribution from local delivery depends on dose : a pilot study with MRI.

BACKGROUND: Tissue distribution after local delivery has been quantified over a period of 5 hours on 7-T MRI in a rabbit model using gadolinium-labeled diethylenetriamine pentaacetic acid (Gd-DTPA) as an antimicrobial surrogate; however, it is unknown how the Gd-DTPA load in a local depot will affect the duration of high-concentration Gd-DTPA in local tissues after surgical débridement. QUESTIONS/PURPOSES: We determined whether the Gd-DTPA load in bone cement affected its local tissue distribution over a period of 1 month after local delivery. METHODS: A 1-cm3 soft tissue dead space was created in the quadriceps of seven rabbits and filled with gadolinium-loaded bone cement. At 7, 14, and 33 days, the volume of tissue with a Gd-DTPA concentration of more than 14 µg/mL was calculated from T1-weighted images using 7-T MRI. Differences in volumes of distribution were analyzed with ANOVA. RESULTS: The volume of tissue with more than 14 µg/mL Gd-DTPA was much larger from higher gadolinium loads on Day 7 (p=0.02) (2121 mm3 for 10 g and 665 mm3 for 1 g) and smaller with time for the 10-g formulation (2121 mm3 on Day 7 and 1241 mm3 on Day 14). CONCLUSIONS: Volume of distribution and duration of Gd-DTPA after local delivery increased with increasing load in the cement and decreased with time. CLINICAL RELEVANCE: For local delivery, high antimicrobial concentrations would be expected in greater volumes of tissue, for longer durations, when higher antimicrobial loads are used.

Increased vascular endothelial growth factor transcription in residual hepatocellular carcinoma after open versus laparoscopic hepatectomy in a small animal model.

BACKGROUND: Vascular endothelial growth factor (VEGF) is overexpressed in hepatocellular carcinoma (HCC), and findings have shown that its upregulation in these tumors has an impact on tumor growth. The authors hypothesized that compared with open liver resection, laparoscopic hepatectomy would result in a decreased local angiogenic response in residual tumor cells. METHODS: Right- and left-lobe hepatomas were induced in Buffalo rats via laparoscopically guided subcapsular injection of Morris hepatoma cells. After 1 week, the animals were randomized to laparoscopic or open left lateral hepatectomy. In 14 days after resection, the rats were killed, the residual right lobe tumors were measured, and tissue was procured for RNA extraction. Transcript levels of VEGF messenger RNA (mRNA) were quantified with reverse transcriptase-polymerase chain reaction (RT-PCR), and VEGF serum levels were measured by enzyme-linked immunoassay (ELISA) both before resection and at the time of tissue harvest. RESULTS: None of the animals had development satellite liver lesions or distant metastases in the abdomen or thorax. The median residual tumor volume was 320 mm(3) in the open group compared with 180 mm(3) in the laparoscopic group (p = 0.164). The animals that underwent open resection had a 1.3-fold increase in VEGF mRNA transcript levels compared with the laparoscopic resection group (p = 0.008). The serum VEGF levels were not significantly different between the laparoscopic and open groups at baseline (open tumor resection [OR], 23.7 +/- 12.0 pg/ml; laparoscopic tumor resection [LR], 30.7 +/- 15.5 pg/ml; p = 0.334) nor at the time of tissue harvest (OR, 19.9 +/- 19.6 pg/ml; LR, 26.9 +/- 34.5 pg/ml; p = 0.549). CONCLUSIONS: Laparoscopic hepatic resection produces decreased VEGF mRNA expression in residual hepatoma cells compared with open resection. Decreased stimulation of angiogenesis promoters in the tumor microenvironment after minimally invasive liver resection may contribute to a lower residual disease burden and ultimately lead to a lower recurrence rate.

VEGF gene therapy augments localized angiogenesis and promotes anastomotic wound healing: a pilot study in a clinically relevant animal model.

BACKGROUND: Anastomotic leak related to ischemia is a source of significant morbidity and mortality in gastrointestinal surgery. The aim of this study was to apply growth factor gene transfection for the purpose of up-regulating angiogenesis, increasing anastomotic strength, and ultimately preventing dehiscence. METHODS: An opossum esophagogastrostomy model was employed. The human vascular endothelial growth factor (VEGF(165)) gene was incorporated into a recombinant plasmid. The VEGF plasmid vector was then complexed with a cationic synthetic carrier, polyethyleneimine. Control animals received plasmid devoid of VEGF(165) (n = 6). The experimental group received VEGF(165) plasmid (n = 5). After esophagogastrectomy and gastric tubularization, plasmid was injected into the submucosa of the neoesophagus at the anastomotic site. Conduit arteriography was performed before and 10 days after injection. Euthanasia occurred on post-injection day 10 and the anastomosis was removed en bloc. A second group of animals treated with VEGF(165) were euthanized 30 and 37 days post injection. Blood flow was measured with laser-Doppler prior to euthanasia. Ex vivo anastomotic bursting pressure was performed. Tissue samples were procured for RNA extraction and von Willebrand Factor staining. Microvessel counts were obtained by two blinded observers. Tissue VEGF transcript levels were measured with reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: There was one anastomotic leak in the control group. Experimental animals demonstrated significantly increased bursting pressure (104.25 +/- 6.2 vs 86.73 +/- 9.4 mmHg, p = 0.021) and neovascularization (33.87 +/- 9.6 vs 20.33 +/- 8.1 vessels/hpf, p = 0.032) compared to controls. In addition, there was a strongly positive correlation between the number of microvessels and bursting pressure (r = 0.808, p = 0.015, Pearson's). On angiographic examination, treated animals demonstrated more neovascularization compared to controls. RT-PCR demonstrated up to a 5.6-fold increase in VEGF mRNA in treated compared to controls. DISCUSSION: This description of gene therapy in gastrointestinal surgery using VEGF(165) transfection demonstrates increased angiogenesis with subsequently improved anastomotic healing in a clinically relevant model.

Microvascular maturity elicited in tissue treated with cytokine-loaded hyaluronan-based hydrogels.

Hydrogels composed of crosslinked, chemically modified hyaluronic acid (HA), gelatin (Gtn) and heparin (Hp) were preloaded with vascular endothelial growth factor (VEGF), angiopoietin-1 (Ang-1), keratinocyte growth factor (KGF) or platelet derived growth factor (PDGF) either individually or in combination with VEGF and implanted into the Balb/c mouse ear pinna. At 7 and 14 days post-surgery, elicited vascular maturity levels were quantified using immunohistochemical (IHC) staining techniques and reported as a vascular maturity index (VMI). At both time points, it was discovered that the dual cytokine combinations elicited greater maturity levels than that of cytokine administered individually. For example, VEGF and KGF-containing HA:Hp implants at day 7 yielded VMI values of -0.1375 and -0.092, respectively, whereas their combination resulted in a VMI of 0.176 (p<0.007). At day 7, only one of the seven HA:Hp experimental cases yielded a positive VMI (VEGF+KGF), whereas four of the seven HA:Hp cases yielded positive VMI values at day 14, indicating a sustained maturity response. The same general trends were found to exist in tissue treated with HA:Hp:Gtn experimental implants. Differences in elicited maturity also existed between tissue treated with HA:Hp and HA-containing hydrogels (VMI=0.176 for HA:Hp-VEGF+KGF vs. -0.064 for HA-VEGF+KGF, p<0.012), and these differences are thought to result from differences in characteristic cytokine release rates. This result also suggests that the presentation of multiple growth factors (GFs) on immobilized Hp may actively contribute to cytokine related signal transduction, a characteristic that may be exploited in the future to improve the efficacy of cytokine-loaded implants towards tissue regeneration therapeutic strategies.