No significant difference in thick versus thin osteochondral flap trochleoplasty in the treatment of trochlear dysplasia: A systematic review

PURPOSE

Trochleoplasty has become increasingly utilised to address patellar instability in the setting of severe trochlear dysplasia. There remains a paucity of literature on the outcomes of 'thick'- versus 'thin'-osteochondral flap trochleoplasty. The purpose of this study is to compare clinical and radiographic outcomes between patients with patellar instability with symptomatic trochlear dysplasia treated using a 'thick' versus 'thin' osteochondral flap trochleoplasty.

METHODS

A systematic review and meta-analysis were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using a PRISMA checklist. Quality assessment of final articles was conducted by two blinded reviewers. Articles were separated based on the use of a 'thick' versus 'thin' flap trochleoplasty. Data collection consisted of recording the following variables: patient demographics, indications for trochleoplasty, mean follow-up time, additional procedures performed during trochleoplasty, patient-reported outcome measures (PROMs), radiographic outcomes (tibial tubercle-trochlear groove [TT-TG] distance, Caton-Deschamps Index [CDI] and sulcus angle [SA]) and the incidence of any postoperative complications and patellar redislocation rates.

RESULTS

A total of 24 studies, consisting of 927 patients, were identified as meeting inclusion criteria. A total of five papers described a 'thick' flap technique, while 19 papers described the use of a 'thin' flap technique. No significant difference in the mean improvement of Kujala scores was appreciated when comparing 'thick' versus 'thin' techniques (p > 0.05). Improvements in mean radiographic outcomes based on TT-TG, CDI and SA were observed in both 'thick' and 'thin' flap trochleoplasty groups. The overall redislocation rate was 0.35%.

CONCLUSION

No significant difference in Kujala scores was observed in patients undergoing trochleoplasty utilising 'thick' versus 'thin' technique, while improvements in mean TT-TG, CDI and SA were noted in both technique groups, with an overall redislocation rate of 0.35%.

LEVEL OF EVIDENCE

Level IV.

The State of Local Antibiotic Use in Orthopedic Trauma

Fracture-related infections are a challenging complication in orthopedic trauma that often necessitates multiple surgeries. Early administration of systemic antibiotics and surgical intervention remains the gold standard of care, but despite these measures, treatment failures can be as high as 35%. For these reasons, the introduction of local antibiotics at the site of at-risk fractures has increased over the past decade. This review looks at the various measures being used clinically including local antibiotic powder, polymethylmethacrylate, biodegradable substances, antibiotic-coated implants, and novel methods such as hydrogels and nanoparticles that have the potential for use in the future.

Thirty-Day Outcomes After Acute Total Hip Arthroplasty Combined With Internal Fixation of Acetabular Fractures: A Multi-Institutional Database Analysis

INTRODUCTION

The purposes of this study were to characterize the 30-day surgical risk of patients undergoing open reduction and internal fixation (ORIF) and total hip arthroplasty stratified by an acetabular fracture pattern and to compare postoperative complications with ORIF alone using a large database.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was queried to determine 30-day outcomes after the combined hip procedure (CHP) compared with ORIF alone between 2005 and 2020. Current Procedural Terminology codes categorized fracture patterns. Univariate analysis was performed using the chi-square, Fisher exact, or Wilcoxon rank sum test. Logistic regression models were fitted to evaluate for any differences in postoperative complications. Total hospital length of stay was compared.

RESULTS

A total of 1,187 patients were identified. One hundred eighty-four patients underwent a CHP, consisting of 99 acetabular wall fractures, 45 elementary acetabular fractures, and 40 associated acetabular fractures. There was no notable difference in any surgical site infection, thromboembolic events, transfusion rates, 30-day revision surgery, and readmission, regardless of the fracture pattern when controlling for comorbidities. Total hospital length of stay was shorter for patients who underwent a CHP for acetabular wall fractures or elementary acetabular fractures (P < 0.001).

CONCLUSION

This combined surgical approach appears to have a similar 30-day risk profile when compared with ORIF alone regardless of the fracture pattern.

Surgical smoke and the orthopedic surgeon: a non-systematic review of the hazards and strategies for mitigating risk

INTRODUCTION

Surgical smoke generated through the use of electrical surgical devices poses a risk to the surgeon, medical personnel in the operating room, and the patient by exposing them to environmentally hazardous particulate matter. Previous investigation has shown that surgical smoke leads to an increased risk of pulmonary conditions, circulatory disorders, and irritation of the eyes, nose, and throat. Transmission of infectious disease can occur through inhalation of viral particles, and the presence of carcinogens are also of major concern. The deleterious effects of surgical smoke are well documented in several subspecialties, namely dermatology and general surgery, but there has been little discussion on the topic amongst orthopedic surgeons.

METHODS

A non-systematic review of the literature was completed with the aim of identifying the major categories of adverse health effects associated with surgical smoke inhalation and offering recommendations to reduce these hazards in the orthopedic surgical community.

RESULTS

Three primary categories of risk associated with surgical smoke inhalation were identified: inflammation, viral/bacterial transmission, and carcinogenicity. In addition, strategies for mitigating risk and best practice recommendations were explored.

CONCLUSION

Surgical smoke is an under-recognized occupational hazard within the orthopedic surgery literature. There are several strategies which can be employed to reduce risk. Further investigation is needed to understand the long-term impact of these risks, as well as what can be done to improve the practicality and compliance with protective measures.

Diagnosing periprosthetic joint infection

Aims

The diagnosis of periprosthetic joint infection (PJI) can be challenging as the symptoms are similar to other conditions, and the markers used for diagnosis have limited sensitivity and specificity. Recent research has suggested using blood cell ratios, such as platelet-to-volume ratio (PVR) and platelet-to-lymphocyte ratio (PLR), to improve diagnostic accuracy. The aim of the study was to further validate the effectiveness of PVR and PLR in diagnosing PJI.

Methods

A retrospective review was conducted to assess the accuracy of different marker combinations for diagnosing chronic PJI. A total of 573 patients were included in the study, of which 124 knees and 122 hips had a diagnosis of chronic PJI. Complete blood count and synovial fluid analysis were collected. Recently published blood cell ratio cut-off points were applied to receiver operating characteristic curves for all markers and combinations. The area under the curve (AUC), sensitivity, specificity, and positive and negative predictive values were calculated.

Results

The results of the analysis showed that the combination of ESR, CRP, synovial white blood cell count (Syn. WBC), and polymorphonuclear neutrophil percentage (PMN%) with PVR had the highest AUC of 0.99 for knees, with sensitivity of 97.73% and specificity of 100%. Similarly, for hips, this combination had an AUC of 0.98, sensitivity of 96.15%, and specificity of 100.00%.

Conclusion

This study supports the use of PVR calculated from readily available complete blood counts, combined with established markers, to improve the accuracy in diagnosing chronic PJI in both total hip and knee arthroplasties.

Utility of Blood Cell Ratio Combinations for Diagnosis of Periprosthetic Joint Infection

Background

Periprosthetic joint infection (PJI) is a serious complication following joint replacement surgery, and its diagnosis can be challenging due to the similarity of symptoms to other conditions and the lack of confirmatory imaging tests. Platelet/mean platelet volume ratio (PVR), platelet/lymphocyte ratio, monocyte/lymphocyte ratio, and neutrophil/lymphocyte ratio have been proposed as potential markers to aid in the diagnosis of PJI. This study aimed to further assess the utility of these blood cell ratio combinations for the diagnosis of PJI.

Methods

A retrospective chart review was conducted on patients who presented to a university hospital for evaluation for PJI or underwent aseptic revision surgery. All patients were reviewed for inclusion in the study. Data were collected on several markers, including complete blood counts, synovial fluid white blood cell count, and polymorphonuclear percentage. Receiver operator characteristic curve analysis was used to evaluate the diagnostic capabilities of the markers and marker combinations.

Results

The combination of erythrocyte sedimentation rate, C-reactive protein, synovial white blood cell count, and synovial polymorphonuclear percentage, with PVR, had the highest area under the curve of 0.97, with a sensitivity of 94.3% and a specificity of 88.9%, and a positive predictive value of 97.1% and a negative predictive value of 80.0%.

Conclusions

This study further supports the use of PVR calculated from complete blood count commonly ordered laboratory values obtained during routine complete blood counts when combined with established serum and synovial markers to increase the diagnostic accuracy for diagnosing PJI.

Arthroscopic versus open irrigation and debridement in native knee septic arthritis: A retrospective review

Introduction

Native knee septic arthritis is a rare condition with a potential for high morbidity if not promptly treated. Treatment involves surgical decompression of the affected joint along with systemic antibiotic therapy. The purpose of this study is to compare arthroscopic versus open irrigation and debridement for treatment of native knee septic arthritis.

Methods

A retrospective review was conducted at a single academic institution of all patients treated for native knee septic arthritis from January 2007 until August 2018 utilizing ICD and CPT codes. Patient demographics, type of surgical procedure, need for reoperation, laboratory values, length of stay, and comorbidities were compared.

Results

A cohort of sixty-six patients who underwent 85 surgeries were included. Among these surgeries, 52 (61%) were arthroscopic while 33 (39%) were open arthrotomies, and 21% required more than one operation. While not statistically significant, the odds of reoperation was higher for those that underwent arthroscopic compared to open irrigation and debridement on univariable (OR = 4.05, p = .08) and multivariable analysis (OR = 4.39, p = .10). Additionally, patients were more likely to require a longer hospital stay if they initially underwent arthroscopic rather than open debridement (RR = 1.31, p = .02).

Conclusion

Native knee septic arthritis can be treated with a single surgery in the majority of cases. In our sample, there was an increased odds of reoperation in those treated arthroscopically compared to open, though this finding was not statistically significant. We found longer length of stay for patients undergoing arthroscopic rather than open irrigation and debridement - even after controlling for multiple operations, culture status, sex, age, and comorbidities.

Surgeon Accuracy in Prediction of Stability of Posterior Wall Acetabular Fractures. A Survey of Orthopaedic Trauma Surgeons

OBJECTIVES

This study aims to investigate surgeon accuracy in prediction of the stability of posterior wall acetabular fractures by comparing "examination under anesthesia" findings to submitted estimations on the basis of radiograph and computed tomography (CT) imaging across a range of experience in orthopaedic surgeons and trainees.

METHODS

Records of patients who underwent examination under anesthesia after presenting with posterior wall acetabular fractures at 2 different institutions were pooled for data collection, totaling 50 cases. Radiographs, CT images, and information regarding the presence of a hip dislocation requiring procedural reduction were provided to participants for review. A survey was generated for submission of impressions of stability for each individual case and disseminated among orthopaedic trainees and surgeons in practice.

RESULTS

The submissions of 11 respondents were analyzed. Mean accuracy was calculated to be 0.70 (SD = 0.07). Sensitivity and specificity of respondents were 0.68 (SD = 0.11) and 0.71 (SD = 0.12), respectively. Positive predictive value and negative predictive value for respondents were 0.56 (SD = 0.09) and 0.82 (SD = 0.04), respectively. There was poor correlation of accuracy with years of experience with R 2 calculated to be 0.0004 and poor agreement between observers with Kappa measurement of interobserver reliability of 0.46.

CONCLUSIONS

Our study suggests that surgeons are unable to consistently differentiate between stable and unstable patterns on the basis of assessments based on x-ray and CT. Years of experience in training or practice was not found to be associated with improved accuracy of stability prediction.

Treatment of Vancouver B2 Femur Fractures With Open Reduction Internal Fixation Versus Revision Arthroplasty

Background Vancouver B2 periprosthetic femur fractures have traditionally been treated with revision arthroplasty. However, there is increasing evidence that open reduction and internal fixation (ORIF) may be a valid alternative treatment strategy. The purpose of this study was to compare the outcomes of ORIF versus revision arthroplasty for the treatment of Vancouver B2 fractures and evaluate the influence of the treating surgeon's fellowship training on treatment selection. Methodology This was a retrospective cohort study of 31 patients treated for Vancouver B2 periprosthetic fractures (16 ORIF and 15 revision arthroplasty) at a single academic Level 1 trauma center. Outcome measures included one-year mortality, revision, reoperation, infection, and blood loss. Results There were no statistically significant differences in revision, reoperation, or infection at an average follow-up of 65 weeks. Median estimated blood loss was higher in the arthroplasty group (700 cc versus 400 cc; P = 0.04). There were five deaths in the ORIF group versus one in the revision group (P = 0.18). Cases treated by surgeons with fellowship training in arthroplasty were more likely to be treated with revision arthroplasty (10/11, 90.9%) than those treated by surgeons with fellowship training in trauma (5/15, 33.3%; P < 0.01). Conclusions There was no difference in outcomes between the two treatment strategies, but revision was associated with higher blood loss. The appropriate treatment method should be based on surgeon familiarity and patients' characteristics.

Cost Analysis of Conversion Total Knee Arthroplasty: A Multi-Institutional Database Study

BACKGROUND

Total knee arthroplasty (TKA) after prior knee surgery, also known as conversion TKA (convTKA), has been associated with higher complications, resource utilization, time, and effort. The increased surgical complexity of convTKA may not be reflected by the relative value units (RVUs) assigned under the current U.S. coding guidelines. The purpose of this study was to compare the RVUs of primary TKA and convTKA and to calculate the RVU per minute to account for work effort.

METHODS

The American College of Surgeons National Surgical Quality Improvement Project (NSQIP) database was analyzed for the years 2005 to 2020. Current Procedural Terminology (CPT) code 27447 alone was used to identify patients who underwent primary TKA, and 27447 plus 20680 were used to identify convTKA. After 1:1 propensity score matching, 1,600 cases were assigned to each cohort. The 2023 Medicare Physician Fee Schedule RVU-to-dollar conversion factor from the U.S. Centers for Medicare & Medicaid Services (CMS) was used to calculate RVU dollar valuations per operative time. Complication rates were compared using a multivariate logistic regression model controlling for baseline characteristics.

RESULTS

The mean operative time for TKA was 97.8 minutes, with a corresponding RVU per minute of 0.25, while the mean operative time for convTKA was 124.3 minutes, with an RVU per minute of 0.19 (p < 0.0001). Using the conversion factor of $33.06 per RVU, this equated to $8.11 per minute for TKA versus $6.39 per minute for convTKA. ConvTKA was associated with higher overall complication (10.9% versus 6.5%, p < 0.0001), blood transfusion (6.6% versus 3.7%, p < 0.01), reoperation (2.3% versus 0.94%, p < 0.0001), and readmission (3.7% versus 1.8%, p < 0.001) rates.

CONCLUSIONS

The current billing guidelines lead to lower compensation for convTKA despite its increased complexity. The longer operative time, higher complication rate, and increased resource utilization may incentivize providers to avoid performing this operation. CPT code revaluation is warranted to reflect the time and effort associated with this procedure.

LEVEL OF EVIDENCE

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Tolerance induction and microglial engraftment after fetal therapy without conditioning in mice with Mucopolysaccharidosis type VII

Mucopolysaccharidosis type VII (MPS7) is a lysosomal storage disorder (LSD) resulting from mutations in the β-glucuronidase gene, leading to multiorgan dysfunction and fetal demise. While postnatal enzyme replacement therapy (ERT) and hematopoietic stem cell transplantation have resulted in some phenotypic improvements, prenatal treatment might take advantage of a unique developmental window to penetrate the blood-brain barrier or induce tolerance to the missing protein, addressing two important shortcomings of postnatal therapy for multiple LSDs. We performed in utero ERT (IUERT) at E14.5 in MPS7 mice and improved survival of affected mice to birth. IUERT penetrated brain microglia, whereas postnatal administration did not, and neurological testing (after IUERT plus postnatal administration) showed decreased microglial inflammation and improved grip strength in treated mice. IUERT prevented antienzyme antibody development even after multiple repeated postnatal challenges. To test a more durable treatment strategy, we performed in utero hematopoietic stem cell transplantation (IUHCT) using congenic CX3C chemokine receptor 1-green fluorescent protein (CX3CR1-GFP) mice as donors, such that donor-derived microglia are identified by GFP expression. In wild-type recipients, hematopoietic chimerism resulted in microglial engraftment throughout the brain without irradiation or conditioning; the transcriptomes of donor and host microglia were similar. IUHCT in MPS7 mice enabled cross-correction of liver Kupffer cells and improved phenotype in multiple tissues. Engrafted microglia were seen in chimeric mice, with decreased inflammation near donor microglia. These results suggest that fetal therapy with IUERT and/or IUHCT could overcome the shortcomings of current treatment strategies to improve phenotype in MPS7 and other LSDs.

O27: MICROGLIAL CORRECTION AFTER FETAL THERAPY WITHOUT CONDITIONING IN MICE WITH MUCOPOLYSACCHARIDOSIS TYPE VII

Introduction

Mucopolysaccharidosis type 7 (MPS7) is a lysosomal storage disorder typically fatal in utero. Postnatal enzyme replacement therapy (ERT) to replace missing glucuronidase (GUS) does not penetrate the blood-brain barrier (BBB). We investigated whether in utero ERT (IUERT) specifically targets brain microglia (natural GUS storehouses and key brain inflammation mediators) and whether in utero hematopoietic stem cell transplantation (IUHSCT) results in microglial engraftment as a strategy for permanent correction.

Methods

We performed IUERT by injecting GUS into MPS7 fetuses mid-gestation, and analyzed tissue homogenates (via colorimetric substrate) and brain microglia (via flow cytometry) for enzyme activity after 4-7 days. We performed IUHSCT by transplanting HSCs mid-gestation from CX3CR1-GFP donors. We examined blood, bone marrow, and brain for engraftment. We assessed brain inflammation by staining for CD68. We performed RNA sequencing to characterize engrafted microglia.

Results

IUERT resulted in detectable brain GUS activity. Flow cytometry showed that GUS activity after IUERT was near wild-type levels, and brains harvested in adulthood had decreased inflammation via CD68 immunohistochemistry. IUHSCT resulted in multilineage engraftment of hematopoietic cells in blood and bone. Confocal microscopy revealed multifocal engraftment of donor-derived microglia. RNA sequencing indicated that engrafted microglia were nearly identical to endogenous microglia. MPS7 chimeras had evidence of reduced brain inflammation near donor microglia.

Conclusion

Both IUERT and IUHSCT are complementary treatment modalities that can penetrate the BBB and ameliorate neurologic manifestations of diseases such as MPS7. These results lay the foundation for future studies using in utero molecular therapies for MPS7 as well as other storage disorders.