Modern Results of Functional Bracing of Humeral Shaft Fractures: A Multicenter Retrospective Analysis.

OBJECTIVES: To evaluate the rate of, and reasons for, conversion of closed treatment of humeral shaft fractures using a fracture brace, to surgical intervention. DESIGN: Multicenter, retrospective analysis. SETTING: Nine Level 1 trauma centers across the United States. PATIENTS: A total of 1182 patients with a closed humeral shaft fracture initially managed nonoperatively with a functional brace from 2005 to 2015 were reviewed retrospectively from 9 institutions. INTERVENTION: Functional brace. MAIN OUTCOME MEASUREMENTS: Conversion to surgery. RESULTS: A total of 344 fractures (29%) ultimately underwent surgical intervention. Reasons for conversion included nonunion (60%), malalignment beyond acceptable parameters (24%), inability to tolerate functional bracing (12%), and persistent signs of radial nerve palsy requiring exploration (3.7%). Univariate comparisons showed that females and whites were significantly (P < 0.05) more likely to be converted to surgery. The multivariate logistic regression identified females as being 1.7 times more likely and alcoholics to be 1.4 times more likely to be converted to surgery (P < 0.05). Proximal shaft as well as comminuted, segmental, and butterfly fractures were also linked to a higher rate of conversion. CONCLUSIONS: This large multicenter study identified a 29% surgical conversion rate, with nonunion as the most common reason for surgical intervention after the failure of functional brace. These results are markedly different than previously reported. These results may be helpful in the future when counseling patients on the choice between functional bracing and surgical intervention in managing humeral shaft fractures. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The biomechanical cost of variable angle locking screws.

INTRODUCTION: Variable angle (VA) locking plates in fracture fixation surgery allow screws to be fastened to the plate within a conical "locus of vectors" in order to avoid existing prostheses, joint surfaces, or poor quality bone. Clinical failures of VA constructs in which screws have rotated at the plate/screw interface have been reported raising the concern that there may be a biomechanical cost for the increased flexibility that VA provides. The objective of this study was to test the mechanical properties of one commonly used VA locking mechanism with screws placed in both nominal and off-axis trajectories and compare these against the standard locking mechanism. METHODS: VA locking screws were inserted into plates for distal femur fractures (VA Curved Condylar) at various angles (0° to 15° away from perpendicular). A control group of standard locking screws/plates was also tested. Maximum moment at the screw/plate interface and moment at two reference displacements were determined. RESULTS: VA screws locked perpendicular to the plate provided the greatest maximum moment and moment at the reference displacements when using the VA system, and demonstrated lower moments compared to standard locking screws/plates (p<0.001). Based on linear regression, there was an average decrease of approximately 0.4 Nm screw-plate interface strength for every 1° increase in screw-plate angle (p<0.001). Decreases (p<0.05) were discovered in both maximum moment and moment at the reference displacements for screws locked at 5° relative to those locked at 0°, 10° relative to 0°, and 15° relative to 10°. DISCUSSION: Standard locking systems provided greater resistance to rotational failure at the screw/plate interface than variable angle locking systems. Variable angle systems provided the greatest resistance to rotation when the screw was inserted perpendicular to the plate. As the off-axis angle increased, the resistance to rotation at the screw/plate interface decreased almost linearly. It is unknown if these differences are clinically significant in an actual fracture construct, but recent reported failures in the distal femur suggest that they might be. CONCLUSION: Surgeons should weigh the risks and benefits of VA systems and attempt to minimize the off-axis angle magnitude when VA systems are selected.

Can Near-infrared Spectroscopy Detect and Differentiate Implant-associated Biofilms?

BACKGROUND: Established bacterial diagnostic techniques for orthopaedic-related infections rely on a combination of imperfect tests that often can lead to negative culture results. Spectroscopy is a tool that potentially could aid in rapid detection and differentiation of bacteria in implant-associated infections. QUESTIONS/PURPOSES: We asked: (1) Can principal component analysis explain variation in spectral curves for biofilm obtained from Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa? (2) What is the accuracy of Fourier transformed-near infrared (FT-NIR)/multivariate data analysis in identifying the specific species associated with biofilm? METHODS: Three clinical isolates, S aureus, S epidermidis, and P aeruginosa were cultured to create biofilm on surgical grade stainless steel. At least 52 samples were analyzed per group using a FT-NIR spectrometer. Multivariate and principal component analyses were performed on the spectral data to allow for modeling and identification of the bacterial species. RESULTS: Spectral analysis was able to correctly identify 86% (37/43) of S aureus, 89% (16/18) of S epidermidis, and 70% (28/40) of P aeruginosa samples with minimal error. Overall, models developed using spectral data preprocessed using a combination of standard normal variant and first-derivative transformations performed much better than models developed with the raw spectral data in discriminating between the three classes of bacteria because of its low Type 1 error and large intermodel distinction. CONCLUSIONS: The use of spectroscopic methods to identify and classify bacterial biofilms on orthopaedic implant material is possible and improves with advanced modeling that can be obtained rapidly with little error. The sensitivity for identification was 97% for S aureus (95% CI, 88-99%), 100% for S epidermidis (95% CI, 95-100%), and 77% for P aeruginosa (95% CI, 65-86%). The specificity of the S aureus was 86% (95% CI, 3-93%), S epidermidis was 89% (95% CI, 67-97%), and P aeruginosa was 70% (95% CI, 55-82%). CLINICAL RELEVANCE: This technique of spectral data acquisition and advanced modeling should continue to be explored as a method for bacterial biofilm identification. A spectral databank of bacterial and potentially contaminating tissues should be acquired initially through an in vivo animal model and quickly transition to explanted devices and the clinical arena.

Cryopreserved human amniotic membrane injection for plantar fasciitis: a randomized, controlled, double-blind pilot study.

BACKGROUND: Treatment options for plantar fasciitis have resulted in varied patient outcomes. The aim of this study was to compare a novel treatment, cryopreserved human amniotic membrane (c-hAM), to a traditional treatment, corticosteroid. Our hypothesis was that c-hAM would be safe and comparable to corticosteroids for plantar fasciitis in regard to patient outcomes. METHODS: A randomized, controlled, double-blind, single-center pilot study was completed. Patients were randomized into one of 2 treatment groups: c-hAM or corticosteroid. Patients received an injection at their initial baseline visit with an option for a second injection at their first 6-week follow-up. Total follow-up was obtained for 12 weeks after the most recent injection. The primary outcome measurement was the Foot Health Status Questionnaire (FHSQ). The secondary outcome measurements were the Visual Analog Scale (VAS) and verbally reported percentage improvement. Data were analyzed between groups for the 2 different cohorts (1 injection versus 2 injections). Twenty-three patients had complete follow-up. Fourteen were randomized to receive corticosteroid and 9 were randomized to receive c-hAM. RESULTS: Three patients in each group received second injections. With the numbers available, the majority of outcome measurements showed no statistical difference between groups. The corticosteroid did, however, have greater FHSQ shoe fit improvement (P = .0244) at 6 weeks, FHSQ general health improvement (P = .0132) at 6 weeks, and verbally reported improvement (P = .041) at 12 weeks in the one-injection cohort. Cryopreserved hAM had greater FHSQ foot pain improvement (P = .0113) at 18 weeks in the 2-injection cohort. CONCLUSION: Cryopreserved hAM injection may be safe and comparable to corticosteroid injection for treatment of plantar fasciitis. This is a pilot study and requires further investigation. LEVEL OF EVIDENCE: Level I, prospective randomized trial.

Concurrent treatment of a middle-third clavicle fracture and type IV acromioclavicular dislocation.

Acromioclavicular (AC) dislocation with an associated displaced fracture of the middle third of the clavicle is a rare injury with no established standard treatment. Previous AC fixation techniques described have not included simultaneous internal fixation of the clavicle. We present the case of a 19-year-old man who sustained this combined injury pattern with a type IV AC dislocation. He underwent open reduction and internal fixation of the clavicle fracture with open reduction of the AC joint and coracoclavicular (CC) screw fixation through the plate to stabilize the AC dislocation. The CC screw was removed 3 months after surgery. By 1-year follow-up, the patient had returned to manual labor and normal activities of daily living. In comparison with previously described treatment, his case highlights a unique approach to this rare shoulder entity.

Unique antimicrobial effects of platelet-rich plasma and its efficacy as a prophylaxis to prevent implant-associated spinal infection.

Platelet-rich-plasma (PRP) has attracted great attention and has been increasingly used for a variety of clinical applications including orthopedic surgeries, periodontal and oral surgeries, maxillofacial surgeries, plastic surgeries, and sports medicine. However, very little is known about the antimicrobial activities of PRP. PRP is found to have antimicrobial properties both in vitro and in vivo. In vitro, the antimicrobial properties of PRP are bacterial-strain-specific and time-specific: PRP significantly (80-100 fold reduction in colony-forming units) inhibits the growth of methicillin-sensitive and methicillin-resistant Staphylococcus aureus, Group A streptococcus, and Neisseria gonorrhoeae within the first few hours but it has no significant antimicrobial properties against E. coli and Pseudomonas. The antimicrobial properties of PRP also depend on the concentration of thrombin. In vivo, an implant-associated spinal infection rabbit model is established and used to evaluate the antimicrobial and wound-healing properties of PRP. Compared to the infection controls, PRP treatment results in significant reduction in bacterial colonies in bone samples at all time points studied (i.e. 1, 2, and 3 weeks) and significant increase in mineralized tissues (thereby better bone healing) at postoperative weeks 2 and 3. PRP therefore may be a useful adjunct strategy against postoperative implant-associated infections.

Repair of large animal partial-thickness cartilage defects through intraarticular injection of matrix-rejuvenated synovium-derived stem cells.

Cartilage defects have a limited ability to self-heal. Stem cell treatment is a promising approach; however, replicative senescence is a challenge to acquiring large-quantity and high-quality stem cells for cartilage regeneration. Synovium-derived stem cells (SDSCs) are a tissue-specific stem cell for cartilage regeneration. Our recent findings suggest that decellularized stem cell matrix (DSCM) can rejuvenate expanded SDSCs in cell proliferation and chondrogenic potential. In this study, we were investigating (1) whether transforming growth factor (TGF)-ß1 and TGF-ß3 played a similar role in chondrogenic induction of SDSCs after expansion on either DSCM or plastic flasks (plastic), and (2) whether DSCM-expanded SDSCs had an enhanced capacity in repairing partial-thickness cartilage defects in a minipig model. SDSCs were isolated from synovium in two 3-month-old pigs and DSCM was prepared using SDSCs. Passage 2 SDSCs were expanded on either DSCM or plastic for one passage. The expanded cells were evaluated for cell morphology, chondrogenic capacity, and related mechanisms. TGF-ß1 and TGF-ß3 were compared for their role in chondrogenesis of SDSCs after expansion on either DSCM or plastic. The chondrogenic induction medium without TGF-ß served as a control. In 13 minipigs, we intraarticularly injected DSCM- or plastic-expanded SDSCs or saline into knee partial-thickness cartilage defects and assessed their repair using histology and immunohistochemistry. We found DSCM-expanded SDSCs were small, had a fibroblast-like shape, and grew quickly in a three-dimensional format with concomitant up-regulation of phosphocyclin D1 and TGF-ß receptor II. Plastic-expanded SDSCs exhibited higher mRNA levels of chondrogenic markers when incubated with TGF-ß3, while DSCM-expanded SDSCs displayed comparable chondrogenic potential when treated with either TGF-ß isotype. In the minipig model, DSCM-expanded SDSCs were better than plastic-expanded SDSCs in enhancing collagen II and sulfated glycosaminoglycan expression in repair of partial-thickness cartilage defects, but both groups were superior to the saline control group. Our observations suggested that DSCM is a promising cell expansion system that can promote cell proliferation and enhance expanded cell chondrogenic potential in vitro and in vivo. Our approach could lead to a tissue-specific cell expansion system providing large-quantity and high-quality stem cells for the treatment of cartilage defects.

Knot security: how many throws does it really take?

The purpose of this study was to determine the minimum number of throws needed for knot security for square knots using 5 common suture materials and 3 common sizes by in vitro single load to failure biomechanical testing. The hypothesis was that each suture combination studied would share a common minimum of at least 5 throws to guarantee security. Five suture materials (FiberWire [Arthrex, Inc, Naples, Florida], Monosof, Surgipro, Maxon, and Polysorb [Covidien, Mansfield, Massachusetts]) with varying suture sizes (#5, #2, 0, 2-0, and 4-0) were tied in vitro, varying the number of square knot throws (3, 4, 5, and 6). Twenty knots for each combination were statically loaded to failure in tension; whether the knot failed by fracture or slippage and the tensile strength at knot failure was determined. For the tested materials, at least 5 flat square throws should be used to confer knot security based on a binomial proportion score 95% confidence interval (CI) 0.84 to 1.0 or at least 4 throws for a 95% CI of 0.76 to 0.99. FiberWire requires 6 flat square throws per knot for security at either 95% CI level. Unless a surgeon has specific knowledge of experimental evidence that fewer throws are necessary for a specific application, the default should be a minimum of 4 throws, with 5 conferring additional security in most situations, and FiberWire requiring 6 throws.

Exaggerated cardiovascular stress responses and impaired beta-adrenergic-mediated pressor recovery in obese Zucker rats.

Clinical studies have demonstrated that the pressor response to acute stress is larger in obese versus lean individuals. We therefore tested the hypotheses that the pressor response to behavioral stress is greater in obese (OZRs) versus lean Zucker rats (LZRs) and that reduced beta-adrenergic-mediated vasodilation contributes to the enhanced pressor response. Animals were restrained and subjected to acute pulsatile air jet stress (3 minutes), followed by a poststress period of 20 minutes; beta-adrenergic blockade was achieved with propranolol (5 mg/kg, IV) given 15 minutes before the start of air jet stress. Mean arterial pressure (MAP) was continuously monitored by telemetry. Untreated OZRs responded with a greater integrated pressor response (area under the curve [AUC]) to acute stress (41.2+/-6.1 versus 21.2+/-3.3 mm Hgx3 minutes, OZR versus LZR; P<0.05) and significantly reduced poststress recovery of MAP. Beta-adrenergic blockade had no effect on stress AUC in either LZRs or OZRs but significantly attenuated the poststress recovery of MAP in LZRs only (poststress AUC: -100.1+/-48.1 versus 49.0+/-13.5 mm Hgx20 minutes, untreated versus propranolol; P<0.05). In anesthetized animals, significantly smaller increases in mesenteric vascular conductance contributed to blunted depressor responses to isoproterenol in OZRs versus LZRs, suggesting that beta-adrenergic stimulation causes a greater reduction in total peripheral resistance in lean versus obese animals. We conclude that beta-adrenergic-mediated vasodilation facilitates blood pressure recovery after stress and that this pathway is compromised in an animal model of morbid obesity, resulting in the impaired ability to regulate blood pressure during stress.