Biomechanical comparison of a novel tensioned cable construct versus tension band wiring for transverse patella fracture fixation.

PURPOSE: Tension band wiring (TBW) is the most widely accepted method for patella fracture fixation. The purpose of our study was to compare the biomechanical efficacy of a novel cable construct to TBW for the fixation of transverse patella fractures. The tensioned cable construct was hypothesized to have less fracture gapping after cyclic flexion-extension loading and greater ultimate load to failure as compared to TBW. METHODS: Transverse patellar osteotomies (AO/OTA 34C1.1) were performed on nine pairs of fresh-frozen human cadaveric whole legs (mean age 82.2 years, range 71-101). Treatment with TBW or tensioned cable construct was randomized within each specimen pair. Fracture site displacement was measured after 5000 flexion-extension cycles from 0° to 90° at 0.5 Hz. In load to failure testing, the knee was fixed at 45° of flexion and the quadriceps tendon was pulled proximally at 0.5 mm/sec until patella fixation failure. Comparisons were made using paired t-tests with alpha values of 0.05. RESULTS: Eight paired specimens completed the cyclic loading. The tensioned cable construct had significantly less fracture gapping than TBW (2.9 vs 10.9 mm; p = 0.020). Seven paired limbs underwent load to failure testing, which revealed no significant difference between the tensioned cable construct and TBW (1551.6 N vs 1664.0 N; p = 0.26). CONCLUSION: In this study of transverse patella fracture fixation, a tensioned cable construct demonstrated significantly less fracture gapping compared to TBW in response to cyclic loading with no significant difference in load at failure.

Donning Gloves Before Surgical Gown Cross-contaminates the Assistant.

Background: Maintaining a sterile surgical environment is of the upmost importance in total joint arthroplasty. The surgical gown-glove interface is a frequent and known cause of bacterial contamination. A variation of the traditional staff-assisted open-gloving technique has been developed in an attempt to address this. In this method, the surgeon dons their undergloves before their gown. Although this has demonstrated improved sterility for the surgeon, no studies have considered the effects of this technique on the person assisting the surgeon. The present study was designed to investigate this. We hypothesize that the process of donning undergloves before the surgical gown leads to higher rates of contamination for the assistant. Methods: We performed a comparative study between the traditional and a gloves-first scrubbing technique. We assessed the differences in gown and glove contamination of the surgical assistant following each scrubbing event. Two surgeons applied ultraviolet light-disclosing lotion to their upper extremities and then performed each method in a randomized order with 40 surgical technologists/nurses. Blinded evaluators then quantified the amount of contamination on the surgical assistant's gown and gloves. Results: The gloves-first technique resulted in increased contamination of the surgical assistant's gloves (P = .002). There was no difference in contamination of the surgical gown (P =.982). Conclusions: Although the staff-assisted open-gloving technique may improve the sterility of the surgeon, it does so at the expense of the surgical assistant. Surgeons adopting this technique should consider donning their own undergloves or having the assistant rescrub before any further contact with the sterile environment.

The positive prediction of single photon emission computed tomography/ computed tomography (SPECT/CT) in the outcome of intervention for cervical facet pain.

BACKGROUND CONTEXT: Previous studies have reported that magnetic resonance imaging (MRI) and computed tomography (CT) do not predict response to facet blocks. However, single photon emission computed tomography (SPECT) uptake within facet joints has been shown to correlate with pain relief after intervention in the lumbar spine. There is minimal data regarding the predictive value of single photon emission computed tomography/computed tomography (SPECT/CT) for neck pain. PURPOSE: The aim of this study was to evaluate the utility of SPECT/CT in patients with axial neck pain for the identification of specific facet joints that would benefit from diagnostic and therapeutic facet joint steroid injections and/or medial branch block/RFA treatments. STUDY DESIGN: A retrospective cohort study. PATIENT SAMPLE: One hundred seventy-nine patients at a single institution pain center with neck pain and a SPECT/CT scan between 2009 and 2015. One hundred twelve patients had no prior intervention at the level of interest and met inclusion criteria. OUTCOME MEASURES: Pain reduction at 50% and 80% thresholds within 24 hours of facet intervention. Concordance of facet intervention with the focus of maximal uptake on SPECT/CT scan. METHODS: All patients were referred to our institution's Center for Pain Medicine and were treated with facet interventions. The site of facet intervention was determined by pain center providers based on their clinical examination and interpretation of images. Groups were formed based on whether the facet intervention included the level of maximal uptake on SPECT/CT scan. A positive response to intervention was defined at both 50% and 80% thresholds for reduction in pain within 24 hours of facet injection with steroid and local anesthetic or medial branch block with local anesthetic only. These were the facet interventions used for our data collection. A Chi-square statistic was used to analyze categorical data and a Student's t-test was used to analyze non-categorical data. SPSS (IBM Corp. IBM SPSS Version 24.0) was used for all analyses. RESULTS: Of our 112 patients, Group 1 consisted of 89 with an intervention occurring at the level with increased uptake on SPECT/CT. Group 2 consisted of 23 patients with an intervention at a level without uptake on SPECT/CT. Demographic data did not significantly differ between cohorts. A Chi-square test of independence demonstrated that intervention at a level concordant with SPECT/CT was significantly correlated with self-reported pain relief thresholds of both 50% and 80% (p=.0002). CONCLUSIONS: Facet interventions based on SPECT/CT scan uptake were more successful in pain reduction than those which were not. This suggests a role for SPECT/CT in diagnosing therapeutic targets for neck pain.

Intraoperative Cryotherapy in the Treatment of Metastatic Renal Cell Carcinoma of the Bone.

Osseous metastases in renal cell carcinoma (RCC) are a heterogeneous mix of cells with hypervascular and rapidly destructive properties that frequently exhibit resistance to both radiation and chemotherapy. Despite this, some patients with isolated and oligometastatic disease have the potential to be cured. Regardless, aggressive metastatic control is critical to minimizing morbidity and mortality for all patients with metastatic RCC. Percutaneous cryoprobes were developed as a minimally invasive technique for both pain relief and tumor control. However, there is little evidence describing an alternative use of this technology in the operating room to assist with open tumor resections, and no formal role for its use in orthopedics exists. Therefore, the authors added this modality to their intraoperative treatment of osseous RCC to investigate whether it would influence their ability to obtain local metastatic control. The authors performed a retrospective chart review of prospectively obtained data to evaluate the role of intraoperative cryotherapy in the treatment of osseous RCC. From 2004 to 2017, cryotherapy was used in 43 procedures, alleviating the need for additional radiation 84% (36 of 43) of the time. Local tumor control was achieved in 100% (43 of 43) of cases. There were 2 wound-related complications and 1 pathologic fracture. Despite the study's limitations, the authors believe that cryotherapy contributed to the reliability and reproducibility of their intralesional resections. Given the palliative, and potentially curative, opportunities afforded by complete locoregional tumor control, the authors support further investigation into the use of intraoperative cryotherapy to treat osseous metastases secondary to RCC. [Orthopedics. 2021;44(5):e645-e652.].

Management of the Pediatric Patient Following Upper Extremity Replantation or Revascularization: A Suggested Protocol.

BACKGROUND: Traumatic pediatric amputations of the hand and upper extremity can have long-term financial, psychological, developmental, and functional consequences that readily extend beyond the realm of that which is normally encountered in comparatively injured adults. These factors, along with a paucity of medical comorbidities, have guided a more liberal and aggressive approach to treating pediatric amputations in hopes of optimizing psychosocial, aesthetic, and developmental outcomes. Furthermore, advances in pharmacology and microsurgical replantation techniques have allowed what were otherwise exceedingly rare surgeries to become commonplace in hospitals all over the world. Despite these gains, vascular thrombosis remains the leading cause of failure in microvascular surgeries. A recent survey showed that 96% of reconstructive surgeons use some form of anticoagulation therapy in their treatment, but no consensus regarding pharmacologic agents, dosing, or efficacy exists. The risk of thrombosis is further complicated by the dynamic nature of vasculature in response to stressors such as sympathetic tone, decreased intravascular volume, and response to external temperature. Given the lack of a higher-level evidence to guide the replantation surgeon in postoperative orders, we created an inclusive protocol, outlining complete and proper management of the pediatric patient following revascularization or replantation surgery. METHODS: We reviewed the methods employed by our microvascular surgeons and consulted with board-certified pediatricians to produce a final document that was adopted ubiquitously among our providers. RESULTS: We do not have head-to-head data demonstrating improved outcomes with use of the protocol. Nonetheless, the original document has been modified and reproduced here for your consideration and use. CONCLUSIONS: Since initiating the protocol, we feel it has helped standardize our practice, avoid instances of incomplete or missed order sets, and facilitate interdisciplinary management through decreased gaps in communication, especially in those surgeries terminating in the middle of the night.

Computational prediction and biochemical characterization of novel RNA aptamers to Rift Valley fever virus nucleocapsid protein.

Rift Valley fever virus (RVFV) is a potent human and livestock pathogen endemic to sub-Saharan Africa and the Arabian Peninsula that has potential to spread to other parts of the world. Although there is no proven effective and safe treatment for RVFV infections, a potential therapeutic target is the virally encoded nucleocapsid protein (N). During the course of infection, N binds to viral RNA, and perturbation of this interaction can inhibit viral replication. To gain insight into how N recognizes viral RNA specifically, we designed an algorithm that uses a distance matrix and multidimensional scaling to compare the predicted secondary structures of known N-binding RNAs, or aptamers, that were isolated and characterized in previous in vitro evolution experiment. These aptamers did not exhibit overt sequence or predicted structure similarity, so we employed bioinformatic methods to propose novel aptamers based on analysis and clustering of secondary structures. We screened and scored the predicted secondary structures of novel randomly generated RNA sequences in silico and selected several of these putative N-binding RNAs whose secondary structures were similar to those of known N-binding RNAs. We found that overall the in silico generated RNA sequences bound well to N in vitro. Furthermore, introduction of these RNAs into cells prior to infection with RVFV inhibited viral replication in cell culture. This proof of concept study demonstrates how the predictive power of bioinformatics and the empirical power of biochemistry can be jointly harnessed to discover, synthesize, and test new RNA sequences that bind tightly to RVFV N protein. The approach would be easily generalizable to other applications.