The Impact of Negative Pressure Wound Therapy on Orthopaedic Infection.

By hastening the resolution of edema and improving local microcirculation, topical negative pressure wound therapy (TNP) aids the establishment of early wound coverage. Its use in the setting of type III open fractures is reviewed. The author's initial use of TNP for closed surgical incisions and how it morphed its way into being applied to closed surgical wounds with heightened likelihood for infection is presented. Several case studies are presented to illustrate the role and the technique for management of acute or subacute infections involving bone and implant.

Investigation of Kryptonite™ bone cement in hybrid screw configurations of locking plate humeral midshaft fixation: A study of surrogate bone model.

PURPOSE: Locking compression plates (LCP) allow trauma and orthopedic surgeons to have a variety of options for utilizing locking and non-locking screw features. In this study, the hybrid constructs of mixed unicortical and bicortical screws were investigated for humerus midshaft fractures. The locking and non-locking features were also incorporated into the hybrid LCP constructs. Kryptonite™ bone cement is biocompatible with low exothermic properties and strong metal adhesion. This novel bone cement was incorporated into the non-locking screw feature to compare its mechanical effect with that of a traditional locking screw feature. METHODS: A total of 24 synthetic bones (Sawbones(®) Inc., USA) were equally divided into three groups (n = 8). The control group obtained traditional LCP fixation (JSM Medimax Inc., India) with bicortical screws, while the hybrid locking constructs employed a mix of bicortical and unicortical screws. The two bicortical screws in hybrid constructs were placed at the end holes of the LCP constructs and the unicortical screws were placed into the remaining holes. The hybrid locking (HL) group contained locking unicortical screws, whereas the hybrid non-locking group (HNK) utilized non-locking screw features incorporating the Kryptonite™ bone cement in the plate/screw bone construct. Specimens were tested by dynamic and static analysis. The eight total constructs were equally divided into two subgroups (n = 4) to conduct axial compression and torsion test individually. The low cyclic test was conducted for dynamic analysis, which included 10,000 cycles at 1 Hz frequency with a cyclic loading of 0-500 N of axial force for the axial compression test and 0-20° of angular displacement for the torsion test. The static analysis was run by a failure test with a nondestructive strain rate of 0.1 mm/s for the axial compression test and 0.5° s(-1) for the torsional test. The construct stiffness of axial compression and torsion were derived from the linear portion of the load-displacement curves. The yield strength of axial compression and torsion was determined by using offset methods. The results of stiffness and yield strength were compared by using both one-way ANOVA and Scheffe and Games-Howell post hoc tests to analyze statically significant differences among the three groups. RESULTS: Specimens completed 10,000 cycles in the dynamic analysis of axial and torsional cyclic tests without major deformation. To compare with the control group in static analysis, the HL and HNK groups achieved positive effect in axial stiffness, 12.3% and 10.5% greater than the control group respectively. HL obtained axial yield strength about 12% less than the control group. The HNK group was equivalent with the control group in axial yield strength. The torsional stiffness and yield strength were found similar in three groups, which indicated torsional equivalence among them. The stiffness and yield strength from axial compression and torsion were found statically non-significant among three groups. CONCLUSIONS: Hybrid LCP constructs were initially showed to maintain equivalent axial and torsional stability with the traditional method. Kryptonite™ hosted mechanical and biological advantages for internal plate/screws (PLT) fixation.

Use of the Reamer/Irrigator/Aspirator Decreases Carotid and Cranial Embolic Events in a Canine Model.

BACKGROUND: Approximately 2 million patients in the United States annually undergo total joint arthroplasty with reaming and placement of intramedullary nails, resulting in extravasation of bone marrow and fat into the circulatory system and potentially causing fat embolism syndrome. Acute and chronic changes in mental status documented after these procedures may be related to embolic events. The Reamer/Irrigator/Aspirator (RIA) device has been shown to decrease intramedullary pressure during reaming. We hypothesized that the use of the RIA in a canine model would reduce the number of microemboli detected in the carotid artery and brain compared with nailing either with or without reaming. METHODS: Twenty-four large canines underwent unreamed nailing (UR), sequentially reamed nailing (SR), or RIA-reamed nailing (RIA) of bilateral femora (eight dogs per group). During reaming and nailing, the number and size of microemboli transiting the carotid artery were recorded. After euthanasia, the brain was harvested for immunostaining and measurement of microinfarction volumes. RESULTS: Total embolic load passing through the carotid artery was 0.049 cc (UR), 0.045 cc (SR), and 0.013 cc (RIA). The number and size of microemboli in the UR and SR groups were similar; however, the RIA group had significantly fewer larger-sized (>200-µm) emboli (p = 0.03). Pathologic examination of the brain confirmed particulate emboli, and histologic analyses demonstrated upregulation of stress-related proteins in all groups, with fewer emboli and less evidence of stress for RIA reaming. CONCLUSIONS: RIA reaming decreased microemboli compared with traditional reaming and unreamed nailing, suggesting that intramedullary pressure and heat are important variables. The documented embolic events and brain stress may help to explain subtle neurobehavioral symptoms commonly seen in patients after undergoing long-bone reaming procedures. CLINICAL RELEVANCE: RIA reaming decreased cranial embolic events and may have an ameliorating effect on postoperative neurologic sequelae.

Infection in Orthopaedics.

Infection in orthopaedic trauma patients is a common problem associated with significant financial and psychosocial costs, and increased morbidity. This review outlines technologies to diagnose and prevent orthopaedic infection, examines implant-related infection and its management, and discusses the treatment of post-traumatic osteomyelitis. The gold standard for diagnosing infection has a number of disadvantages, and thus new technologies to diagnose infection are being explored, including multilocus polymerase chain reaction with electrospray ionization-mass spectrometry and optical imaging. Numerous strategies have been employed to prevent orthopaedic infection, including use of antibiotic-impregnated implant coatings and cement; however, further research is required to optimize these technologies. Biofilm formation on orthopaedic implants is attributed to the glycocalyx-mediated surface mode of bacterial growth and is usually treated through a secondary surgery involving irrigation, debridement and the appropriate use of antibiotics, or complete removal of the infected implant. Research into the treatment of post-traumatic osteomyelitis has focused on developing an optimal local antibiotic delivery vehicle, such as antibiotic-impregnated polymethylmethacrylate (PMMA) cement beads or bioabsorbable bone substitute (BBS) delivery systems. As these new technologies to diagnose, prevent and treat orthopaedic infection advance, the incidence of infection will decrease and patient care will be optimized.

Negative pressure wound therapy in grade IIIB tibial fractures: fewer infections and fewer flap procedures?

BACKGROUND: Grade IIIB open tibia fractures are devastating injuries. Some clinicians advocate wound closure or stable muscle flap coverage within 72 hours to limit complications such as infection. Negative pressure wound therapy was approved by the FDA in 1997 and has become an adjunct for many surgeons in treating these fractures. Opinions vary regarding the extent to which negative pressure wound therapy contributes to limb salvage. Evidence-based practice guidelines are limited for use of negative pressure wound therapy in Grade IIIB tibia fractures. This systematic literature review of negative pressure wound therapy in Grade IIIB tibia fractures may substantiate current use and guide future studies. QUESTIONS/PURPOSES: We sought to answer the following: (1) Does the use of negative pressure would therapy compared with gauze dressings lead to fewer infections? (2) Does it allow flap procedures to be performed safely beyond 72 hours without increased infection rates? (3) Is it associated with fewer local or free flap procedures? METHODS: We conducted a systematic review of six large databases (through September 1, 2013) for studies reporting use of negative pressure wound therapy in Grade IIIB open tibia fractures, including information regarding infection rates and soft tissue reconstruction. The systematic review identified one randomized controlled trial and 12 retrospective studies: four studies compared infection rates between negative pressure wound therapy and gauze dressings, 10 addressed infection rates with extended use, and six reported on flap coverage rates in relation to negative pressure wound therapy use beyond 72 hours. None of the 13 studies was eliminated owing to lack of study quality. RESULTS: Negative pressure wound therapy showed a decrease in infection rates over rates for gauze dressings in two of four studies (5.4% [two of 35] versus 28% [seven of 25], and 8.4% [14 of 166] versus 20.6% [13 of 63]), an equivalent infection rate in one study (15% [eight of 53] versus 14% [five of 16]), and an increased infection rate in the fourth study (29.5% [23 of 78] versus 8% [two of 25]). In terms of the second question regarding infection rates with negative pressure wound therapy beyond 72 hours, eight of 10 studies concluded there was no increase in infection rates, whereas two of 10 reported an increase in infection rates associated with negative pressure wound therapy use beyond 72 hours. Infection rates varied from 0% to 57% in these 10 studies. Five studies reported low infection rates of 0% to 7% and five reported rates of 27% to 57%. The third question (addressed by six studies) regarded the potential decreased use of a soft tissue flap in patients treated with extended negative pressure wound therapy. Flap rates were reduced by 13% to 60% respectively compared with those of historical controls. Grade IIIB tibia fractures by definition required soft tissue procedures. The patients in these six studies had Grade IIIB tibia fractures after the first débridement. However, after extended negative pressure wound therapy, fewer patients required flaps than grading at the first débridement would have predicted. CONCLUSIONS: There is an increasing body of data supporting negative pressure wound therapy as an adjunctive modality at all stages of treatment for Grade IIIB tibia fractures. There is an association between decreased infection rates with negative pressure wound therapy compared with gauze dressings. There is evidence to support negative pressure wound therapy beyond 72 hours without increased infection rates and to support a reduction in flap rates with negative pressure wound therapy. However, negative pressure wound therapy use for Grade IIIB tibia fractures requires extensive additional study. LEVEL OF EVIDENCE: Level III, therapeutic study.

Microvascular effects of subatmospheric pressure in striated muscle.

OBJECTIVE: Topical application of subatmospheric pressure (TASAP) promotes faster wound healing, but tissue effects are not entirely understood. This study investigated microvascular effects of TASAP in striated muscle with the hypothesis being that TASAP elicits arteriolar vasodilation and decreases interstitial accumulation of protein. METHODS: Rat cremasteric microcirculation was directly examined in two experiments utilizing a novel technique. First, TASAP was applied to the cremaster in three experimental groups and a non-TASAP control group. Arteriolar diameters were directly measured before and after TASAP. In experiment two, intravascular fluorescein isothiocyanate (FITC)-labeled albumin and topical leukotriene B4 (LTB4) were delivered to the cremaster. Microvascular permeability was assessed by measuring the accumulation/disappearance of FITC-albumin in the interstitial tissue. RESULTS: TASAP produced significant arteriolar vasodilation compared with control values. The mean maximum percent increase in diameter with TASAP was 8.70% at -2 kPa (p < 0.05), 7.16% at -4 kPa (p < 0.05), and 10.43% at -6 kPa (p < 0.01). TASAP decreased interstitial FITC-albumin by 26.3% (p < 0.008) following LTB4; the control group showed a steady increase in interstitial FITC-albumin. CONCLUSIONS: These results support the hypothesis that TASAP elicits significant arteriolar vasodilation with a subsequent increase in blood flow as well as a decrease in interstitial protein accumulation.

Value of 3-D CT in classifying acetabular fractures during orthopedic residency training.

The complex anatomy of the pelvis and acetabulum have historically made classification and interpretation of acetabular fractures difficult for orthopedic trainees. The addition of 3-dimensional (3-D) computed tomography (CT) scan has gained popularity in preoperative planning, identification, and education of acetabular fractures given their complexity. Therefore, the authors examined the value of 3-D CT compared with conventional radiography in classifying acetabular fractures at different levels of orthopedic training. Their hypothesis was that 3-D CT would improve correct identification of acetabular fractures compared with conventional radiography.The classic Letournel fracture pattern classification system was presented in quiz format to 57 orthopedic residents and 20 fellowship-trained orthopedic traumatologists. A case consisted of (1) plain radiographs and 2-dimensional axial CT scans or (2) 3-D CT scans. All levels of training showed significant improvement in classifying acetabular fractures with 3-D vs 2-D CT, with the greatest benefit from 3-D CT found in junior residents (postgraduate years 1-3).Three-dimensional CT scans can be an effective educational tool for understanding the complex spatial anatomy of the pelvis, learning acetabular fracture patterns, and correctly applying a widely accepted fracture classification system.

Soft-tissue management after trauma: initial management and wound coverage.

Before proceeding with treatment, it is necessary to recognize that bony injuries are always associated with soft-tissue disruption and damage. A good soft-tissue envelope is essential to fracture healing and overall extremity function. Injury management begins by recognizing and classifying the injury. Wound débridement with irrigation fluid at low pressure and the administration of antibiotics are essential aspects of treatment. Wound treatment starts with applying dressing material using negative suction and can be guided by the tenets of an algorithm modeled on the reconstructive ladder.

The mangled limb: salvage versus amputation.

A mangled extremity is defined as a limb with injury to three of four systems in the extremity. The decision to salvage or amputate the injured limb has generated much controversy in the literature, with studies to support advantages of each approach. Various scoring systems have proved unreliable in predicting the need for amputation or salvage; however, a recurring theme in the literature is that the key to limb viability seems to be the severity of the soft-tissue injury. Factors such as associated injuries, patient age, and comorbidities (such as diabetes) also should be considered. Attempted limb salvage should be considered only if a patient is hemodynamically stable enough to tolerate the necessary surgical procedures and blood loss associated with limb salvage. For persistently hemodynamically unstable patients and those in extremis, life comes before limb. Recently, the Lower Extremity Assessment Project study attempted to answer the question of whether amputation or limb salvage achieves a better outcome. The study also evaluated other factors, including return-to-work status, impact of the level of and bilaterality of the amputation, and economic cost. There appears to be no significant difference in return to work, functional outcomes, or the cost of treatment (including the prosthesis) between the two groups. A team approach with different specialties, including orthopaedics, plastic surgery, vascular surgery and trauma general surgery, is recommended for treating patients with a mangled extremity.

Infection.

Musculoskeletal infection is a clinical problem with significant direct healthcare costs. The prevalence of infection after closed, elective surgery is frequently estimated to be less than 2%, but in severe injuries, posttraumatic infection rates have been reported as 10% or greater. Although clinical infections are found outside the realm of medical devices, it is clear that the enormous increase of infections associated with the use of implants presents a major challenge worldwide. This review summarizes recent advances in the understanding, diagnosis, and treatment of musculoskeletal infections.

The effect of incisional negative pressure therapy on wound complications after acetabular fracture surgery.

The purpose of the study was to determine if the use of incisional negative pressure therapy affected the rate of wound complications after acetabular fracture surgery. Between August 1996 to April 2005, 301 patients were found to have had an operatively treated acetabular fracture. There were 235 patients who had placement of incisional vacuum-assisted closure (VAC) who had three (1.27%) deep wound infections and one (0.426%) wound dehiscence. There were 66 consecutive patients who were available in the 5 years preceding the usage of the incisional VAC who had four (6.06%) deep wound infections and two (3.03%) wound dehiscences. This is less than the published infection rate of 4% for patients undergoing operative treatment of acetabular fractures and less than the authors' rate of 6.15% in the time period before the use of the incisional negative pressure wound therapy (p=.0414). The use of incisional negative pressure wound therapy significantly decreases perioperative wound complications after acetabular fracture surgery.

Incisional vacuum-assisted wound closure in morbidly obese patients undergoing acetabular fracture surgery.

We studied the effect of incisional vacuum-assisted closure (IVAC) on wound complications (dehiscences, infections) associated with surgical treatment of acetabular fractures in morbidly obese patients (body mass index, >40 kg/m(2)). No wound complications were found in 19 consecutive patients over 5 years of IVAC use. IVAC is an attractive treatment adjunct for minimizing postoperative wound complications in morbidly obese patients undergoing acetabular fracture surgery.

Relationship between intraoperative femoral head bleeding and development of avascular necrosis after acetabular fracture surgery.

The purpose of this study was to determine whether the presence or absence of bleeding after drilling of the femoral head can be used to predict the development of avascular necrosis (AVN) after operative treatment of acetabular fractures. A computerized medical record search from 1996 to 2005 of all patients with an operatively treated acetabular fracture yielded 146 patients who had an intraoperative assessment of the vascularity of their femoral head and 72 of whom were available for a minimum of 12 months of follow-up. The average time to the development of AVN was 99.6 weeks with a range of 21-290 weeks. Eleven of the patients in the analysis eventually developed AVN. The p value is not significant at. 092. Although the difference between groups is not significant, it does appear that there is a relationship between femoral head bleeding and the development of avascular necrosis.

Encapsulated Staphylococcus aureus strains vary in adhesiveness assessed by atomic force microscopy.

Staphylococcus aureus capsular polysaccharides are believed to play a role in adhesion to surfaces and may contribute to their antimicrobial resistance, thereby increasing the rates and severity of associated infections. The purpose of this study was to compare the adhesiveness of distinct S. aureus capsular polysaccharides to determine whether adhesiveness was a general or specific feature across different S. aureus strains. Atomic force microscopy was used to confirm the presence or absence of capsular polysaccharides and to measure adhesive forces on a noncapsulated, serotype 8, and serotype 2 strain of S. aureus. Serotype 8 displayed a larger range of adhesive forces (1-19 nN) than the noncapsulated (0-4 nN) and serotype 2 (0-4 nN) strain. The majority of adhesive forces for serotype 8 were in the 10-15 nN range. Removal of capsular polysaccharides gave a marked decrease in adhesive forces measured for serotype 8 and, to a lesser extent, a decrease for serotype 2. Noncapsulated, serotype 8, and serotype 2 S. aureus had water contact angles of 23.8 (+/-8.9), 34.4 (+/-2.5), and 56.7 (+/-11.2) degrees (mean +/- standard deviation), respectively. For the first time, capsular polysaccharides from serotype 8 (clinically common) and serotype 2 (clinically rare) were demonstrated to have different physical properties, which may account for variations in studies in which clinical isolates are utilized, and the conflict in proposed roles for capsular polysaccharides on S. aureus is explained.

History of open wound and fracture treatment.

This introduction summarizes historical aspects regarding improvements in the treatment of open fractures and complicated wounds. Before the development of standardized surgical wound treatment and antisepsis, amputations were frequently required to prevent sepsis and death. Nowadays, the use of modern sealing techniques has caused a further dramatic reduction in the infection rates and an improvement of the healing response, thus enabling orthopaedic surgeons to perform skin graft coverage, where previously plastic surgeons had to perform skin flaps.

Current thought regarding the mechanism of action of negative pressure wound therapy with reticulated open cell foam.

There are currently 2 main theories regarding the mechanism of action of negative pressure wound therapy with reticulated open cell foam (NPWT/ROCF) as delivered by V.A.C.(R) Therapy (KCI, San Antonio, TX). The first is based on the stimulatory effect of microstrain on cellular mitogenesis, angiogenesis, and elaboration of growth factors. This is the same mechanism that is operational in controlled Ilizarovian distraction or in tissue expansion. The second is based on the enhancement of the dynamics of microcirculation by active evacuation of excess interstitial fluid in the form of edema. Physiologically, there is a lowering of the heightened capillary afterload and a qualitative dilution of contained microcontaminants, bacteria, and proinflammatory cytokines. Based on these effects, the use of NPWT/ROCF has found a place in the management of high-energy traumatic wounds and certain high-risk elective surgical wounds.

Evidence of beneficial effect of physical therapy after lower-extremity trauma.

OBJECTIVE: To examine the effect of physical therapy (PT) use on a range of measures of physical impairment in a cohort of patients with lower-extremity trauma. DESIGN: Longitudinal, observational study of patients with severe lower-extremity trauma. Patients were interviewed by a research coordinator and examined by an orthopedic surgeon and a physical therapist during initial admission and at 3, 6, 12, and 24 months postdischarge. SETTING: Eight level I trauma centers. PARTICIPANTS: Patients (N=382) whose legs were salvaged after limb-threatening trauma to the lower limb. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Unmet need for PT was assessed from 2 perspectives: an orthopedic surgeon and a physical therapist independently evaluated each patient and were asked whether the patient would benefit from PT. Patients classified by these health professionals as needing PT services over a given period and who reported receiving no PT at the end of that period were classified as having unmet need as evaluated by the orthopedic surgeon or physical therapist for that follow-up period. Multiple variable regression techniques were used to compare improvement in 5 measures of physical impairment and functional limitation between the met and unmet need groups over the periods of 3 to 6, 6 to 12, and 12 to 24 months: percentage of impairment in knee and ankle range of motion (ROM), reciprocal stair climbing pattern, gait deviations when walking, self-selected walking speed greater than 1.2 m/s (4 ft/s), and the mobility subscores of the FIM instrument. RESULTS: Patients with unmet need for PT as assessed by a physical therapist were statistically significantly less likely to improve in all 5 of the selected domains of physical impairment and functional limitation than patients whose PT need was met. These results remained constant after adjustment for patient sociodemographic, personality, and social resources, as well as injury and treatment characteristics, reported pain intensity, and impairment level at the beginning of the study period. Patients with unmet need for PT as evaluated by an orthopedic surgeon were significantly worse off than patients with met need in only 1 of the 5 selected measures (ROM). CONCLUSIONS: The results are consistent with a beneficial effect of PT after lower-extremity trauma. The results point to a need for improved standards for the prescription of PT services, and highlight the importance of involving a PT professional in the prescribing process.

The long lost art of preoperative planning--resurrected?

Tibial plateau fractures are complex injuries that can affect both knee function and stability. In the past, surgeons have relied on radiographs, viewboxes, tracing paper, and scaled acetate templates to formulate a preoperative plan. With the advent of digital radiography, viewboxes, and standard radiographs are no longer routinely available. The availability of a digital format for preoperative planning has helped to address this, but fragment manipulation and implant templating are not features of most digital radiography systems. Digital surgical planning software allows for these functions thereby enabling the surgeon to formulate a preoperative plan for fracture reduction and fixation. Concomitant use of 3-dimensional (3D) imaging software permits unlimited inspection of the fracture by allowing for oblique or special views through manipulation of the software image as opposed to potentially painful positioning of the injured limb by the patient or radiograph personnel. This case report illustrates the advantages of these new software tools.