Effects of Upper Extremity Elevation on Intra-Cast Pressure and Digital Perfusion in a Fiberglass Short-Arm Cast Model.

The goal of this study was to determine the relationship of digital artery pressure to arm position and forearm skin surface pressure using a short-arm cast experimental setup, to ascertain the safest position for the injured casted upper extremity. A total of 27 volunteers were placed in bilateral short-arm fiber-glass casts with an empty 50-mL bladder bag under the cast and attached to a pressure transducer. Digital systolic pressure (Pdig), and skin surface pressure under the cast (Pskin) were assessed in 4 positions. Measurements were taken with and without 50 mL air in the bladder bag. A total of 54 forearms were evaluated. Both arm position and Pskin had a significant effect on Pdig (P<.001 for both), with increasing elevation leading to a decrease in Pdig (r=-0.50). The effect size of position on Pdig was large, whereas that of Pskin was small (partial eta-squared=0.371 and 0.028, respectively). Linear regression analysis of Pskin and Pdig with air in the neutral position yielded a moderate negative relationship with body mass index (r=-0.64, P<.001 for Pskin; r=0.49, P<.001 for Pdig) and wrist circumference (r=-0.66, P<.001 for Pskin; r=0.52, P<.001 for Pdig), without significant association with forearm length. For volunteers with short-arm fiberglass casts, increasing arm elevation had a large effect size on digital arterial pressure, whereas 50 mL simulated swelling had only a small effect size. Decreasing body mass index and forearm circumference correlated with increased skin surface pressure and decreased digital arterial pressure. These findings show that aggressive elevation of the injured limb may not be as desirable as previously believed. [Orthopedics. 2021;44(4):e487-e492.].

Biomechanical Comparison of Titanium Locking Fragment-Specific and Volar Locking Plates for AO B1 and B2 Fractures of the Distal Radius.

PURPOSE: This biomechanical study compared the stability of volar locking plates (VLPs) and locking fragment-specific (LFS) dorsal and radial styloid plates for the fixation of dorsal (AO 23-B2) and radial styloid (AO 23-B1) shear fractures of the distal radius, respectively. METHODS: Two groups of 6 composite radii were fixed with a VLP or an LFS dorsal plate over a simulated dorsal shear fracture. Two additional groups of 6 radii received the same VLP or an LFS radial plate to fix a radial styloid fracture. Each plated radius was tested under cyclic axial compression by a servohydraulic testing machine that recorded axial displacement per cycle. Construct stiffness was calculated from the slope of the force-displacement curve. RESULTS: In the dorsal shear fracture model, the dorsal LFS plate exhibited less displacement than the VLP (0.32 ± 0.04 vs 0.43 ± 0.07 mm, respectively) and showed greater average stiffness (645 ± 64 vs 433 ± 88 N/mm, respectively). Plate type was responsible for 53.1% of the variation in displacement and 68.6% of the variation in stiffness. In the radial styloid fracture model, variations due to number of cycles elapsed and plate type were similar for displacement and stiffness in both groups. The average stiffness during cyclical nondestructive testing was 566 ± 45 and 573 ± 60 N/mm for VLP and LFS radial plating groups, respectively. CONCLUSIONS: For AO 23-B2 (dorsal rim) fractures, the dorsal LFS plates exhibited significantly less displacement and greater stiffness in axial loading than VLPs. For AO 23-B1 (radial styloid) fractures, the VLP displayed similar displacement and stiffness to the radial LFS plates. CLINICAL RELEVANCE: All constructs tested could be expected to withstand axial compressive forces typical of early postoperative rehabilitation.

Touch Surgery: Analysis and Assessment of Validity of a Hand Surgery Simulation "App".

BACKGROUND: Surgical educators are increasingly exploring surgical simulation and other nonclinical teaching adjuncts in the education of trainees. The simulators range from purpose-built machines to inexpensive smartphone or tablet-based applications (apps). This study evaluates a free surgery module from one such app, Touch Surgery, in an effort to evaluate its validity and usefulness in training for hand surgery procedures across varied levels of surgical experience. METHODS: Participants were divided into 3 cohorts: fellowship-trained hand surgeons, orthopedic surgery residents, and medical students. Participants were trained in the use of the Touch Surgery app. Each participant completed the Carpal Tunnel Release module 3 times, and participants' score was recorded for each trial. Participants also completed a customized Likert survey regarding their opinions on the usefulness and accuracy of the app. Statistical analysis using a 2-tailed t test and analysis of variance was performed to evaluate for performance within and between cohorts. RESULTS: All cohorts performed better on average with each subsequent simulation attempt. For all attempts, the experts outperformed the novice and intermediate participants, while the intermediate cohort outperformed the novice cohort. Novice users consistently gave the app better scores for usefulness as a training tool, and demonstrated more willingness to use the product. CONCLUSIONS: The study confirms app validity and usefulness by demonstrating that every cohort's simulator performance improved with consecutive use, and participants with higher levels of training performed better. Also, user confidence in this app's veracity and utility increased with lower levels of training experience.

Prolonged Preoperative Weakness Affects Recovery of Motor Function After Anterior Cervical Diskectomy and Fusion.

INTRODUCTION: Some patients who undergo anterior cervical diskectomy and fusion for radiculopathy or myelopathy demonstrate preoperative weakness. The purpose of this study was to determine which factors predict motor recovery in patients undergoing anterior cervical diskectomy and fusion. METHODS: A retrospective review of our institutional database identified patients undergoing anterior cervical diskectomy and fusion between 2010 and 2013 with 2 years of clinical follow-up. Patients with substantial weakness, defined as preoperative grade ≤3 (on a scale from 0 to 5) in one or more upper extremity muscle groups, were identified. Regression analysis was used to determine risk factors associated with persistent postoperative weakness. RESULTS: Of the 1,001 patients who were included, 54 (5.4%) demonstrated substantial weakness. By 2 years postoperatively, 47 of 54 patients (87%) demonstrated motor recovery. The duration of preoperative weakness was an independent predictor of recovery (median, 4 months of preoperative weakness among patients with recovery versus 10 months in patients with persistent weakness; P = 0.012). DISCUSSION: Duration of preoperative motor weakness is an independent predictor of motor recovery after anterior cervical diskectomy and fusion in patients with substantial motor weakness. CONCLUSION: Patients being considered for anterior cervical diskectomy and fusion who have substantial preoperative motor deficits may benefit from earlier surgical intervention.

Can We Reduce the Utilization of Home-Visiting Nurse Services After Primary Total Joint Arthroplasty?

BACKGROUND: Home-visiting nurse services (HVNSs) after total joint arthroplasty (TJA) are touted as advantageous compared with inpatient rehabilitation. No study has established the utility of HVNSs compared with discharge home without services. METHODS: A retrospective single-surgeon consecutive series of 509 primary TJA patients compared discharge disposition, length of stay, complications, and patient satisfaction between 2 cohorts. The cohorts were defined by the elimination of routine HVNSs. RESULTS: Surprisingly, without routine HVNSs, more patients were discharged home (95% vs 88.3% with routine HVNSs) and mean length of stay significantly decreased. Complication rate was similar (2.9% vs 3.9% with routine HVNSs). Patient satisfaction remained favorable. We estimated that eliminating HVNSs avoids excess costs of $1177 per hip and $1647 per knee arthroplasty. CONCLUSIONS: With dramatically diminished HVNS utilization after primary TJA, there was an associated decrease in length of stay and no increase in complication rate suggesting no compromise of patient care with significant cost savings.

Intraoperative Proximal Femoral Fracture in Primary Cementless Total Hip Arthroplasty.

Intraoperative proximal femoral fracture is a complication of primary cementless total hip arthroplasty (THA) at rates of 2.95-27.8%. A retrospective review of 2423 consecutive primary cementless THA cases identified 102 hips (96 patients) with fracture. Multivariate analysis compared fracture incidences between implants, Accolade (Stryker Orthopaedics) and Tri-Lock (DePuy Orthopaedics, Inc.), and evaluated potential risk factors using a randomized control group of 1150 cases without fracture. The fracture incidence was 4.4% (102/2423), 3.7% (36/1019) using Accolade and 4.9% using Tri-Lock (66/1404) (P=0.18). Female gender (OR=1.96; 95% CI 1.19-3.23; P=0.008) and smaller stem size (OR=1.64; 95% CI 1.04-2.63; P=0.03) predicted increased odds of fracture. No revisions of the femoral component were required in the fracture cohort.

Local vanadium release from a calcium sulfate carrier accelerates fracture healing.

This study evaluated the efficacy of using calcium sulfate (CaSO4 ) as a carrier for intramedullary delivery of an organic vanadium salt, vanadyl acetylacetonate (VAC) after femoral fracture. VAC can act as an insulin-mimetic and can be used to accelerate fracture healing in rats. A heterogenous mixture of VAC and CaSO4 was delivered to the fracture site of BB Wistar rats, and mechanical testing, histomorphometry, micro-computed tomography (micro-CT) were performed to measure healing. At 4 weeks after fracture, maximum torque to failure, effective shear modulus, and effective shear stress were all significantly higher (p < 0.05) in rats treated with 0.25 mg/kg VAC-CaSO4 as compared to carrier control rats. Histomorphometry found a 71% increase in percent cartilage matrix (p < 0.05) and a 64% decrease in percent mineralized tissue (p < 0.05) at 2 weeks after fracture in rats treated with 0.25 mg/kg of VAC-CaSO4 . Micro-CT analyses at 4 weeks found a more organized callus structure and higher trending maximum connected z-ray. fraction for VAC-CaSO4 groups. Evaluation of radiographs and serial histological sections at 12 weeks did not show any evidence of ectopic bone formation. As compared to previous studies, CaSO4 was an effective carrier for reducing the dose of VAC required to accelerate femoral fracture healing in rats.

Local insulin therapy affects fracture healing in a rat model.

A significant number of lower extremity fractures result in mal-union necessitating effective treatments to restore ambulation. Prior research in diabetic animal fracture models demonstrated improved healing following local insulin application to the fracture site and indicated that local insulin therapy can aid bone regeneration, at least within an insulin-dependent diabetic animal model. This study tested whether local insulin therapy could accelerate femur fracture repair in normal, non-diabetic rats. High (20 units) and low (10 units) doses of insulin were delivered in a calcium sulfate carrier which provided sustained release of the exogenous insulin for 7 days after fracture. Histomorphometry, radiographic scoring, and torsional mechanical testing were used to measure fracture healing. The fracture calluses from rats treated with high-dose insulin had significantly more cartilage than untreated rats after 7 and 14 days of healing. After 4 weeks of healing, femurs from rats treated with low-dose insulin had significantly higher radiographic scores and mechanical strength (p < 0.05), compared to the no treatment control groups. The results of this study suggest that locally delivered insulin is a potential therapeutic agent for treating bone fractures. Further studies are necessary, such as large animal proof of concepts, prior to the clinical use of insulin for bone fracture treatment.

The effects of local vanadium treatment on angiogenesis and chondrogenesis during fracture healing.

This study quantified the effects of local intramedullary delivery of an organic vanadium salt, which may act as an insulin-mimetic on fracture healing. Using a BB Wistar rat femoral fracture model, local vanadyl acetylacetonate (VAC) was delivered to the fracture site and histomorphometry, mechanical testing, and immunohistochemistry were performed. Callus percent cartilage was 200% higher at day 7 (p < 0.05) and 88% higher at day 10 (p < 0.05) in the animals treated with 1.5 mg/kg of VAC. Callus percent mineralized tissue was 37% higher at day 14 (p < 0.05) and 31% higher at day 21 (p < 0.05) in the animals treated with 1.5 mg/kg of VAC. Maximum torque to failure was 104% and 154% higher at 4 weeks post-fracture (p < 0.05) for the healing femurs from the VAC-treated (1.5 and 3.0 mg/kg) animals. Animals treated with other VAC doses demonstrated increased mechanical parameters at 4 weeks (p < 0.05). Immunohistochemistry detected 62% more proliferating cells at days 7 (p < 0.05) and 94% more at day 10 (p < 0.05) in the animals treated with 1.5 mg/kg VAC. Results showed 100% more vascular endothelial growth factor-C (VEGF-C) positive cells and 80% more blood vessels at day 7 (p < 0.05) within the callus subperiosteal region of VAC-treated animals (1.5 mg/kg) compared to controls. The results suggest that local VAC treatment affects chondrogenesis and angiogenesis within the first 7-10 days post-fracture, which leads to enhanced mineralized tissue formation and accelerated fracture repair as early as 3-4 weeks post-fracture.