Cathodic voltage-controlled electrical stimulation and betadine decontaminate nosocomial pathogens from implant surfaces.

Periprosthetic joint infection (PJI) after total joint arthroplasty is a major concern requiring multiple surgeries and antibiotic interventions. Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli are the predominant causes of these infections. Due to biofilm formation, antibiotic treatment for patients with PJI can prolong resistance, further complicating the use of current treatments. Previous research has shown that cathodic voltage-controlled electrical stimulation (CVCES) is an effective technique to prevent/treat implant-associated biofilm infections on titanium (Ti) surfaces. This study thus evaluated the efficacy of CVCES via the use of 10% betadine alone and in combination with CVCES to eradicate lab-grown biofilms on cemented and cementless cobalt-chromium (CoCr) and Ti surfaces. CVCES treatment alone for 24 hours demonstrated no detectable CFU for E. coli and P. aeruginosa biofilms on cementless CoCr implants. In the presence of cement, E. coli biofilms had 106 CFUs/implant remaining after CVCES treatment alone; however, P. aeruginosa biofilms on cemented implants were reduced to below detectable limits. The use of 10% betadine treatment for 3 minutes followed by 24-hour CVCES treatment brought CFU levels to below detectable limits in E. coli and P. aeruginosa. The same was true for S. aureus biofilms on cementless patellofemoral implants as well as femoral and tibial implants. These treatment methods were not sufficient for eradication of S. aureus biofilms on cemented implants. These results suggest that CVCES alone and CVCES with 10% betadine are effective approaches to treating biofilms formed by certain bacterial species potentially leading to the treatment of PJI.IMPORTANCEPeriprosthetic joint infections (PJIs) are problematic due to requiring multiple surgeries and antibiotic therapies that are responsible for increased patient morbidity and healthcare costs. These infections become resistant to antibiotic treatment due to the formation of biofilms on the orthopedic surfaces. Cathodic voltage-controlled electrical stimulation (CVCES) has previously been shown to be an effective technique to prevent and treat biofilm infections on different surfaces. This study shows that CVCES can increase the efficacy of 10% betadine irrigation used in debridement, antibiotics, and implant retention by 99.9% and clear infection to below detection limits. PJI treatments are at times limited, and CVCES could be a promising technology to improve patient outcomes.

Pathogenic genetic variations of C. acnes are associated with clinically relevant orthopedic shoulder infections.

Many surgeons continue to face the clinical dilemma of interpreting a positive aspiration or unexpected positive Cutibacterium acnes (C. acnes) culture. There are factors that complicate the interpretation of positive cultures including variations in both frequency of false positive cultures and virulence properties. As indices of virulence, hemolytic strains, from previously confirmed clinically infected shoulders, were compared with non-hemolytic isolates determined to be contaminants, by RNA-sequencing (RNA-Seq). Six C. acnes isolates from patients who underwent revision total shoulder arthroplasty (TSA) were identified based on previously described infection criteria. Three C. acnes isolates from each group underwent RNA-Seq. Differential gene expression analysis, principal component analysis (PCA), and heatmap analysis were used to determine the gene variation and patterning between the definite infection and probable contaminant isolates. Differential gene expression analysis identified genes that were differentially expressed between the isolates classified as definite infection and isolates classified as probable contaminants. PCA using a 500 gene subset of identified genes was able to find combinations of these genes that separated out the definite infection and probable contaminants isolates. The heatmap demonstrated similar gene expression in the three Definite Infections isolates, and significantly different expression when compared with the probable contaminant isolates. Clinical significance: C. acnes revision TSA isolates classified as definite infection and probable contaminant demonstrated a similar gene expression pattern to each respective group and different gene expression pattern when compared between groups. These findings indicate distinct differences in C. acnes strains associated with clinically relevant orthopedic TSA infections.

Flexion Space Balancing Through Component Positioning and Its Relationship to Traditional Anatomic Rotational Landmarks in Robotic Total Knee Arthroplasty.

BACKGROUND: The use of the femoral component position to balance the flexion space and its relationship to the transepicondylar axis (TEA) and posterior condylar angle (PCA) has not been thoroughly evaluated. METHODS: A total of 233 patients undergoing robotic arm-assisted total knee arthroplasty were evaluated. Native TEA and PCA were established on preoperative computed tomography scans. Femoral component rotation was set in the axial plane to match the native trochlea and native medial femoral condyle to set the flexion gap. Knee flexion space gaps and component position were recorded. The relationship of the femoral component to the native TEA, PCA, and preoperative radiographic landmarks was evaluated. RESULTS: The intraoperative measured medial flexion space gap did not significantly correlate with the relationship of the femoral component to the PCA or TEA in varus or valgus knees. In varus knees, the preoperative mechanical axis alignment had a positive relationship to femoral component position when compared to the PCA (P = .04) and TEA (P = .002). In valgus knees, there was a positive correlation between the preoperative lateral distal femoral angle and component position when compared to the PCA (P = .04) only. CONCLUSION: Intraoperative measured flexion space balance through femoral component positioning did not correlate with its relationship to the native TEA or PCA. In varus knees, the preoperative mechanical axis alignment correlated with an increase in femoral component external rotation to the TEA and PCA. In valgus knees, the severity of preoperative lateral distal femoral angle correlated with the rotational relationship of the femoral component to the PCA only.

Nationwide Organism Susceptibility Patterns to Common Preoperative Prophylactic Antibiotics: What Are We Covering?

BACKGROUND: Many periprosthetic joint infections (PJIs) are caused by organisms not susceptible to first-generation cephalosporins. We sought to evaluate the national susceptibility patterns of organisms to cefazolin and, or oxacillin, clindamycin, and vancomycin using antibiogram data. METHODS: Publically available regional and state antibiograms were evaluated for antibiotic susceptibility patterns to commonly infecting gram-positive organisms. The number of isolates tested in each antibiogram and percent of strains susceptible to oxacillin, clindamycin, and vancomycin were recorded. Oxacillin is used as a surrogate to cefazolin in antibiograms. A comparison of antibiotic susceptibilities was performed. RESULTS: Seven state and 38 regional antibiograms were reviewed. Oxacillin was a sensitive antibiotic in 99.2 ± 4.8% of methicillin-sensitive Staphylococcus aureus (MSSA) isolates, 0 ± 0% of methicillin-resistant Staphylococcus aureus (MRSA) isolates, 44.5 ± 13.7% of coagulase-negative staphylococcus organism isolates (CNS), and 30.6 ± 10.5% of Staphylococcus epidermidis isolates. Clindamycin was a sensitive antibiotic in 75.8 ± 8.4% of MSSA isolates, 60.2 ± 13.2% of MRSA isolates, 60.3 ± 11.4% of CNS isolates, and 56.2 ± 6.5% of S epidermidis isolates. Vancomycin was a sensitive antibiotic in 99.9 ± 0.4% of MSSA isolates, 99.8 ± 0.4% of MRSA isolates, 99.8 ± 0.5% of CNS isolates, and 99.6 ± 0.7% of S epidermidis isolates. Clindamycin was significantly less sensitive in MSSA isolates as compared with oxacillin and vancomycin (P < .0001). Oxacillin was significantly less sensitive in CNS, S epidermidis, and MRSA isolates as compared with clindamycin and vancomycin (P < .0001). CONCLUSION: The national clindamycin susceptibility pattern is limited to MSSA and may not have an optimal susceptibility profile suitable for use as a prophylactic antibiotic. Cefazolin continues to have excellent coverage against MSSA.

Hemolysis Is a Diagnostic Adjuvant for Propionibacterium acnes Orthopaedic Shoulder Infections.

INTRODUCTION: The purpose of this study was to further evaluate the pathogenicity of hemolytic and nonhemolytic phenotypes of Propionibacterium acnes (P acnes) isolates from shoulders of orthopaedic patients. METHODS: Thirty-one patient records were reviewed, which had a positive P acnes shoulder culture from joint aspiration fluid and/or intraoperative tissues for demographics, clinical course, culture, and laboratory data. Patients were categorized as definite infection, probable infection, or probable contaminant. Antibiotic resistance patterns and hemolysis characteristics were subsequently analyzed. RESULTS: Hemolysis demonstrated 100% specificity with a positive predictive value of 100% and 80% sensitivity with a negative predictive value of 73% for determining definite and probable infections. Hundred percent of the patients in the hemolytic group and only 27% of patients in the nonhemolytic group were classified as infected. Presenting inflammatory markers were markedly higher in the hemolytic group. Clindamycin resistance was found in 31% of the hemolytic strains, whereas no antibiotic resistance was observed in the nonhemolytic group. CONCLUSION: Hemolytic strains of P acnes exhibit enhanced pathogenicity to their host by eliciting a more prominent systemic inflammatory response, increased antibiotic resistance, and a more challenging clinical course. Hemolysis may serve as a specific marker for assisting in diagnosing true infection with P acnes. LEVEL OF EVIDENCE: Level III retrospective comparative study.

Tranexamic Acid Reduces Perioperative Blood Loss and Hemarthrosis in Total Ankle Arthroplasty.

Tranexamic acid (TXA) is an effective agent used for reducing perioperative blood loss and decreasing the potential for postoperative hemarthrosis. We hypothesized that patients who had received intraoperative TXA during total ankle arthroplasty (TAA) would have a reduction in postoperative drain output, thereby resulting in a reduced risk of postoperative hemarthrosis and lower wound complication rates. A retrospective review was conducted on 50 consecutive patients, 25 receiving TXA (TXA-TAA) and 25 not receiving TXA (No TXA-TAA), who underwent an uncemented TAA between September 2011 and December 2015. Demographic characteristics, drain output, preoperative and postoperative hemoglobin levels, operative and postoperative course, and minor and major wound complications of the patients were reviewed. Drain output was significantly less in the TXA-TAA group compared to that in the No TXA-TAA group (71.6 ± 60.3 vs 200.2 ± 117.0 mL, respectively, P < .0001). The overall wound complication rate in the No TXA-TAA group was higher (20%, 5/25) than that in the TXA-TAA group (8%, 2/25) (P = .114). The mean change in preoperative to postoperative hemoglobin level was significantly less in the TXA-TAA group compared to that in the No TXA-TAA group (1.5 ± 0.6 vs 2.0 ± 0.4 g/dL, respectively, P = .01). TXA is an effective hemostatic agent when used during TAA. TXA reduces perioperative blood loss, hemarthrosis, and the risk of wound complications.

The Use of Antibiograms in Orthopedic Surgery.

PURPOSE OF REVIEW: Organism identification and antibiotic selection remain a critical component of periprosthetic joint infection (PJI) treatment. Prior to organism identification and/or the availability of antibiotic sensitivities, empiric antibiotics are routinely started. A basic understanding of a region or institutions antibiogram is paramount for selection of an empiric treatment regimen. Evolving antibiogram results and regional antibiotic resistance are important to follow as this may change antibiotic selection in some patient populations. RECENT FINDINGS: The Clinical Laboratory and Standards Institute (CLSI) has created guidelines and standards for the creation and maintenance of antibiograms that should be followed by institutions. The infecting organism during PJI may be different in acute vs chronic infections and empiric therapy may change depending on the timing. Antibiotic prophylaxis for major procedures in certain patient populations should be critically evaluated based on regional and national antibiogram results. The CLSI guides recommendations and antibiotic resistance testing techniques and should be consulted when creating an antibiogram. The local and regional antibiogram should be consulted prior to administration of empiric and prophylactic antibiotics.

Centers for Disease Control and Prevention 2017 Guidelines for Prevention of Surgical Site Infections: Review and Relevant Recommendations.

PURPOSE OF REVIEW: The associated patient morbidity and resource-intensive nature of managing surgical site infections (SSI) has focused attention toward not only improving treatment protocols but also enhancing preventative measures. The purpose of this review was to summarize the relevant updated CDC guidelines for the prevention of SSI that were released in 2017. The CDC recommends the integration of the guidelines for improvement in quality metrics, reportable outcomes, and patient safety. RECENT FINDINGS: The updated guidelines include generalized recommendations for parenteral antimicrobial prophylaxis, non-parenteral antimicrobial prophylaxis, glycemic control, normothermia, oxygenation, and antiseptic prophylaxis. The arthroplasty section includes recommendations for blood transfusion, systemic immunosuppressive therapy, and antibiotics during drain use. There was low-quality evidence precluding recommendations for preoperative intra-articular corticosteroid injections, orthopedic surgical space suits, and biofilm management. The recommendations provided throughout this review, including more recent guidelines from other organizations such as the AAOS and ACR, should assist clinicians in developing and/or refining surgical site prevention protocols for their patients undergoing total joint arthroplasty procedures.

The flexion space is more reliably balanced when using the transepicondylar axis as compared to the posterior condylar line.

PURPOSE: The purpose of this study was to evaluate the differences in flexion space balance when the femoral component is implanted parallel to the surgical transepicondylar axis (TEA) or with 3° of external rotation from the posterior condylar line (PoCoLi). It was hypothesized that implantation parallel to the TEA will produce a more reliably balanced flexion space. METHODS: Forty-eight consecutive patients with a varus deformity were prospectively randomized to undergo total knee arthroplasty with a femoral component implanted parallel the TEA, or with 3° of external rotation from the PoCoLi. The posterior condylar angle (PCA) was measured. Intraoperative load measurements were taken at 10°, 45°, and 90° of flexion. RESULTS: The PCA was similar between groups (TEA group: 4.2° ± 1.5° and PoCoLi group: 4.0° ± 1.3°; n.s.). The mean difference in load values between the medial and lateral compartments was significantly lower in the TEA group than in the PoCoLi group at the 45 (0 ± 8 vs. 9 ± 13 lbs; respectively, p = 0.008) and 90° flexion angles (1 ± 9 vs. 10 ± 15 lbs; respectively, p = 0.01). The PoCoLi group had a linear increase in the difference of load values between the medial and lateral compartments with increasing magnitude of the posterior condylar angle (45°, p = 0.0013; 90°, p = 0.0006), but this was not observed in the TEA group. CONCLUSION: Femoral component implantation parallel to the TEA resulted in a more balanced flexion gap as compared to implantation at 3° of external rotation from the PoCoLi. The intraoperative use of the TEA rather than the PoCoLi to set femoral component rotation may provide a more balanced flexion space and decrease the need for extensive soft tissue releases. LEVEL OF EVIDENCE: II.

Uncemented vs Cemented Cruciate Retaining Total Knee Arthroplasty in Patients With Body Mass Index Greater Than 30.

BACKGROUND: Aseptic loosening of cemented and uncemented tibial components continues to be a source of implant failure after total knee arthroplasty (TKA) in the obese population. There is limited literature reviewing uncemented cruciate retaining (CR) components in the obese population. METHODS: A clinical and radiographic review was performed on 325 patients who underwent a cemented or uncemented TKA with a CR knee prosthesis and body mass index ≥30 kg/m2 between January 2010 and June 2013. Charts were reviewed for the incidence of revision due to aseptic loosening of the tibial baseplate, revision for any reason, incidence of radiolucent lines around the tibial baseplate, range of motion, and patient reported outcomes. RESULTS: There was no statistically significant difference between groups in survivorship for aseptic loosening of the tibial component (99.4% uncemented, 99.3% cemented, P = .94) and overall survivorship (98.1% uncemented, 98.3% cemented, P = .90). The Lower Extremity Activity Scale and Forgotten Joint Score-12 clinical outcome measures were similar between groups (10.2 ± 3.7 vs 9.7 ± 3.4 and 66.1 ± 28.2 vs 64.9 ± 24.3, P = .33, P = .78, respectively). Postoperative knee flexion was similar between groups (114.6 ± 9.3 vs 114.1 ± 9.3, P = .67). CONCLUSION: Our study demonstrated similar survivorship of this CR design for aseptic loosening of the tibial baseplate and overall revision rates in obese patients undergoing either an uncemented or cemented TKA. The uncemented and cemented groups had comparable clinical and radiographic short to mid-term outcomes when implanted in good alignment when treating end-stage knee osteoarthritis.

The location of the medial parapatellar arthrotomy influences intraoperative patella tracking.

PURPOSE: The medial parapatellar arthrotomy (MPPA) is a commonly utilized surgical approach; however, the placement of the arthrotomy and its influence on intraoperative patellar tracking has not been evaluated. METHODS: Six knees from three fresh frozen cadavers with transthoracic amputations were operated on. All underwent standard posterior stabilized total knee arthroplasty using a medial parapatellar approach placed at the border of the vastus medialis oblique (VMO)-quadriceps junction. Patellae were resurfaced in the standard fashion. All patellae tracked normally with the first arthrotomy placed at the junction of the VMO-quadriceps tendon using the "no touch" technique. Measurement of patellar lift-off from the implant surface of the medial aspect of the trochlea on the femoral component was made at 50°, 75°, and 90° of flexion and a merchant view radiograph taken to evaluate radiographic patellar tilt. To simulate a more lateral placement of the MPPA, a 5-6 mm slice of quadriceps tendon was then removed from the lateral aspect of the tendon from the patellar insertion to the most proximal portion of the arthrotomy. This simulated a 5-6 mm more lateral placement of the parapatellar arthrotomy. The same measurements and radiographs were taken as described previously. Two more times the same size slices was removed from the quadriceps tendon with subsequent measurements and radiographs obtained. RESULTS: The mean patellar lift-off with the first arthrotomy was 0 ± 0 mm for 50°, 75°, and 90° of flexion. The mean lift with the second arthrotomy was 2 ± 2, 3 ± 3, and 4 ± 3 mm respectively. The third arthrotomy had a mean patellar lift-off of 3 ± 2, 4 ± 3, and 8 ± 2 mm respectively, while the fourth arthrotomy had a mean lift-off of 6 ± 2, 8 ± 2, and 9 ± 4 mm. There was a significant correlation between percentage of quadriceps cut at 1 cm above the superior pole of the patella and patellar lift-off at 50° (R 2 = 0.70; p < 0.0001), 75° (R 2 = 0.68; p < 0.0001), and 90° (R 2 = 0.68; p < 0.0001) of flexion. CONCLUSION: The location of the MPPA has a significant influence on intraoperative assessment of patellar tracking. An MPPA more lateral in the quadriceps tendon may independently influence the patellar tilt observed intraoperatively and should be taken into consideration when evaluating intraoperative patella tracking. An understanding of the independent influence the MPPA has on patellar tracking may decrease the need for lateral release if the surgeon notes the MPPA was made more than 5-10 mm from the junction of the VMO-quadriceps tendon junction.

Bone morphogenic protein-2 use in revision total hip arthroplasty with acetabular defects.

INTRODUCTION: The restoration of acetabular bone stock during revision hip arthroplasty remains a challenge. There have been no clinical series reporting the efficacy of bone morphogenic protein-2 (rhBMP-2) in the revision hip setting. METHODS: We retrospectively reviewed the radiographs and records of 15 patients who received rhBMP-2 mixed with allograft bone chips (+BMP), and 14 who received allograft bone chips alone (-BMP) for their acetabular defect during revision total hip arthroplasty with a mean two-year follow up. Radiographs were evaluated for acetabular defect size, superior cup migration, and changes in the lateral cup abduction angle. Modified Harris hip scores were used for evaluation of clinical outcomes. RESULTS: Patients in the +BMP group compared to the -BMP group had significantly larger amounts of cancellous bone chips used (72.1 ± 35.5 cc vs. 38.6 ± 14.1 cc; p = 0.003). Mean rhBMP-2 used per case was 7.4 ± 3.1 mg in the +BMP group. Three patients in the -BMP group had cup migration which was not observed in the +BMP group. Mean Harris hip scores (HHS) improved post-operatively in both groups (40.1 ± 20.9 to 71.9 ± 19, p < .0001). No local adverse reaction was noted in the +BMP group. CONCLUSION: rhBMP-2 had modest clinical benefit in the setting of revision THA. Cost of this synthetic biologic versus the added clinical benefit should be carefully considered when being used in the revision hip setting.

Provider-Initiated Patient Satisfaction Reporting Yields Improved Physician Ratings Relative to Online Rating Websites.

Recently, providers have begun to publicly report the results of patient satisfaction surveys from their practices. However, these outcomes have never been compared with the findings of commercial online physician rating websites. The goals of the current study were to (1) compare overall patient satisfaction ratings for orthopedic surgeons derived from provider-based third-party surveys with existing commercial physician rating websites and (2) determine the association between patient ratings and provider characteristics. The authors identified 12 institutions that provided publicly available patient satisfaction outcomes derived from third-party surveys for their orthopedic surgeons as of August 2016. Orthopedic surgeons at these institutions were eligible for inclusion (N=340 surgeons). Provider characteristics were recorded from publicly available data. Four high-traffic commercial online physician rating websites were identified: Healthgrades.com, UCompareHealthCare.com, Vitals.com, and RateMDs.com. For each surgeon, overall ratings (on a scale of 1-5), total number of ratings, and percentage of negative ratings were compared between provider-initiated internal ratings and each commercial online website. Associations between baseline factors and overall physician ratings and negative ratings were assessed. Provider-initiated internal patient satisfaction ratings showed a greater number of overall patient ratings, higher overall patient satisfaction ratings, and a lower percentage of negative comments compared with commercial online physician rating websites. A greater number of years in practice had a weak association with lower internal ratings, and an academic practice setting and a location in the Northeast were protective factors for negative physician ratings. Compared with commercial online physician rating websites, provider-initiated patient satisfaction ratings of orthopedic surgeons appear to be more favorable, with greater numbers of responses. [Orthopedics. 2017; 40(5):304-310.].

Success rates, characteristics, and costs of articulating antibiotic spacers for total knee periprosthetic joint infection.

BACKGROUND: The optimal type, characteristics, and success rates of articulating antibiotic spacers used during total knee arthroplasty (TKA) periprosthetic joint infection (PJI) have not been well defined in a single series. We sought to (1) determine the success rate for three unique spacer constructs and (2) evaluate any microbiological, surgical, or patient characteristics that would influence the success rate. METHODS: We retrospectively reviewed patients who underwent a two-stage exchange for a TKA PJI with a prefabricated spacer (PREFAB), home-made mold (MOLD), or autoclaved femoral component (AUTOCL). Patient demographics, microbiology data, amount of antibiotic in each spacer construct, postoperative course, and infection cure outcomes were evaluated. RESULTS: The success rate for being infection free at final follow-up without the need for further reoperation for infection was 82.7% in the PREFAB group, 88.4% in the MOLD group, and 79.4% in the AUTOCL group (p=0.54). There was no clear statistical link between raw quantities of vancomycin and aminoglycoside in the spacer and a successful outcome. The surgeon's own intraoperatively created mold group had the lowest construct cost at a mean $1341.00±889.10 (p<0.0001) per construct, while the commercial cement molds had the highest mean cost at $5439.00±657.80 (p<0.0001). CONCLUSIONS: There was no statistically significant difference in the success rates between the antibiotic spacer types. The surgeon's own intraoperative mold had the least overall associated cost.

Propionibacterium acnes Host Inflammatory Response During Periprosthetic Infection Is Joint Specific.

BACKGROUND: Propionibacterium acnes (P. acnes) has become increasingly recognized as a cause of periprosthetic joint infection (PJI). QUESTIONS/PURPOSES: It is not currently known if the clinical presentation of P. acnes varies depending on the joint being infected. METHODS: We retrospectively reviewed patients infected with P. acnes after total hip, knee, and shoulder arthroplasty from two institutions. Patients were classified as having a PJI based on the Musculoskeletal Infection Society criteria and were excluded if they had a polymicrobial culture. Patient demographics, preoperative laboratory values, and microbiology data were analyzed. RESULTS: Eighteen knees, 12 hips, and 35 shoulders with a P. acnes PJI were identified. Median ESR was significantly higher in the knee (38.0 mm/h, IQR 18.0-58.0) and hip (33.5 mm/h, IQR 15.3-60.0) groups compared to the shoulder group (11.0 mm/h, IQR 4.5-30.5). C-reactive protein levels were higher in the knee (2.0 mg/dl, IQR 1.3-8.9) and hip (2.4 mg/dl, IQR 0.8-4.9) groups compared to the shoulder group (0.7 mg/dl, IQR 0.6-1.5). Median synovial fluid WBC was significantly higher in the knee group than shoulder group (19,950 cells/mm3, IQR 482-60,063 vs 750 cells/mm3, IQR 0-2825, respectively). Peripheral blood WBC levels were similar between groups, as was mean time of P. acnes growth in culture. Clindamycin resistance was present in all groups. CONCLUSION: The manner in which a patient with P. acnes PJI presents is joint specific. Inflammatory markers were significantly higher in the knee and hip groups compared to the hip and shoulder groups, and long hold anaerobic cultures up to 14 days are necessary to accurately identify this organism.

Radiographic outcomes of cable-plate versus cable-grip fixation in periprosthetic fractures of the proximal femur.

BACKGROUND: Newer generation cable-plate designs are commonly used for periprosthetic proximal femur fractures; however, comparisons relative to cable-grips remain limited. The aim of this study was to compare radiographic healing rates of cable-plate versus cable-grip fixation for periprosthetic proximal femur fractures. PATIENTS AND METHODS: Consecutive patients with an acute or chronic Vancouver A, B1, or B2 periprosthetic proximal femur fracture undergoing trochanteric fixation with a cable-plate (n = 46 cases) or cable-grip (n = 24 cases) system were identified retrospectively from a single-centre hospital database (mean follow-up 28 months [range 6-89 months]). Demographics, radiographic fracture healing, and complications were compared between the 2 groups. Radiographic union rates were not different between the cable-grip versus cable-plate group (67% vs. 76% respectively; p = 0.4). Healing rates of greater trochanteric fractures alone were not different between the cable-plate versus cable-grip groups (75% vs. 71% respectively; p = 0.38). The cable-plates were used for a more diverse range of fracture patterns relative to the cable-grips. RESULTS: An increased number of cables was associated with radiographic healing (odds ratio 14 [95% confidence interval 2-64]; p = 0.01), and body mass index had a negative correlation with radiographic healing (odds ratio -0.4 [95% confidence interval 0.5-0.9]. CONCLUSIONS: Similar rates of periprosthetic fracture healing were seen using a cable-grip versus cable-plate system; however, the cable-plate system could be used for a more diverse range of fracture patterns.

The Influence of a Failed Irrigation and Debridement on the Outcomes of a Subsequent 2-Stage Revision Knee Arthroplasty.

BACKGROUND: Previous work has suggested a failed irrigation and debridement (I&D) before a 2-stage exchange negatively impacts the outcome of the subsequent 2-stage revision. METHODS: This was a retrospective review of 132 patients who underwent a 2-stage exchange without prior I&D (2-Stage), and 45 patients had a failed I&D before their 2-stage exchange (I&D+2Stage) between April 2009 and April 2015. Charts were reviewed for patient demographics, presenting inflammatory laboratory values, type of antibiotic spacer used, surgical details, microbiology data, length of postoperative antibiotic treatment, and reoperation. A logistic regression was used to assess the association between I&D and reoperation. RESULTS: The I&D+2Stage group had an 82.2% success rate, and the 2-Stage group had an 82.5% success rate (P = .95). The odds of reoperation for infection with the use of greater than 2 grams of vancomycin was 0.33 (P = .01, 95% confidence interval 0.14-0.79) as compared with having less than 2 grams of vancomycin in the construct. Spacer type, having a prior I&D to the 2-stage procedure, being infected with an antibiotic resistant organism, total grams of aminoglycoside were not associated with a risk of failure. CONCLUSION: Success rates between the I&D+2Stage group and the 2-Stage group were similar. The use of greater than 2 grams of vancomycin in the spacer construct decreased the odds of reoperation. I&D before a 2-stage exchange may not negatively influence the outcomes of a subsequent 2-stage revision procedure and requires further investigation.

MRI, Retrieval Analysis, and Histologic Evaluation of Adverse Local Tissue Reaction in Metal-on-Polyethylene Total Hip Arthroplasty.

BACKGROUND: The severity and location of adverse local tissue reaction (ALTR) seen in metal-on-polyethylene total hip arthroplasty (THA) is not well described. METHODS: We retrospectively reviewed the records of patients who underwent a revision THA using our biomechanics database. We included all patients who underwent revision surgery for the diagnosis of ALTR with THA implants that had modularity solely at the head-neck junction and excluded patients with implant modularity at sites other than the head-neck junction. Magnetic resonance imaging (MRI) was evaluated by a fellowship-trained radiologist who specializes in evaluating metal artifact reducing MRI sequences to quantify the ALTR lesions. Histology was evaluated for findings of ALTR using the Campbell score. RESULTS: We identified 11 patients in the database. Eight patients had an MRI ALTR grade of severe and 7 did based on the histology score. The mean synovial volume was 218,658 mm3 (range 23,461-451,435 mm3) with a mean maximal synovial thickness of 15.3 mm (range 3-34.3 mm). A disruptive infiltration of the abductors due to pseudocapsule invasion was seen in 67% of the patients with 3 not having abductor involvement. Mean preoperative cobalt and chromium levels were 5.4 ppb (range 1-12.3 ppb) and 1.1 ppb (range 0.6-2.4 ppb), respectively. CONCLUSION: Patients with ALTR from head-neck junction corrosion in metal-on-polyethylene THA may present with large pseudotumors that have previously been under appreciated. Mean preoperative serum cobalt and chromium ion levels remained relatively low, and MRI was an effective way to characterize the size and location of these lesions.