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.

Elevated Radiation Exposure Associated With Above Surface Flat Detector Mini C-Arm Use.

Background: This study aims to test the hypothesis that: (1) radiation exposure is increased with the intended use of Flat Surface Image Intensifier (FSII) units above the operative surface compared with the traditional below-table configuration; (2) this differential increases in a dose-dependent manner; and (3) radiation exposure varies with body part and proximity to the radiation source. Methods: A surgeon mannequin was seated at a radiolucent hand table, positioned for volar distal radius plating. Thermoluminescent dosimeters measured exposure to the eyes, thyroid, chest, hand, and groin, for 1- and 15-minute trials from a mini C-arm FSII unit positioned above and below the operating surface. Background radiation was measured by control dosimeters placed within the operating theater. Results: At 1-minute of exposure, hand and eye dosages were significantly greater with the flat detector positioned above the table. At 15-minutes of exposure, hand radiation dosage exceeded that of all other anatomic sites with the FSII in both positions. Hand exposure was increased in a dose-dependent manner with the flat detector in either position, whereas groin exposure saw a dose-dependent only with the flat detector beneath the operating table. Conclusions: These findings suggest that the surgeon's hands and eyes may incur greater radiation exposure compared with other body parts, during routine mini C-arm FSII utilization in its intended position above the operating table. The clinical impact of these findings remains unclear, and future long-term radiation safety investigation is warranted. Surgeons should take precautions to protect critical body parts, particularly when using FSII technology above the operating with prolonged exposure time.

Reliability of Metacarpal Subsidence Measurements after Thumb Carpometacarpal Joint Arthroplasty.

BACKGROUND: Thumb metacarpal subsidence after trapeziectomy can affect clinical function over time. Methods for measuring subsidence after trapeziectomy have been described, and they rely on an intact thumb metacarpal or proximal phalanx for measurement. The authors evaluated the reliability and reproducibility of measuring the trapezial space ratio, using previously described methods. In addition, the authors evaluated a new method that measures trapezial space on a posteroanterior (PA) hand/wrist radiograph that does not rely on an intact thumb metacarpal or proximal phalanx for measurement, which can often be altered by degenerative changes or in cases in which metacarpophalangeal arthrodesis is performed during carpometacarpal (CMC) joint arthroplasty to correct excessive hyperextension. The authors hypothesized that a new method of calculating trapezial space would have comparable reliability and reproducibility to previously proposed methods. METHODS: Thirty-seven PA hand/wrist radiographs from patients who had trapeziectomy with ligament reconstruction and tendon interposition were evaluated. Trapezial space was measured using PACS (Picture Archiving and Communication System) digital tools as the distance perpendicular to the tangents of the scaphoid and first metacarpal joint surfaces. All X-rays were evaluated individually by five fellowship-trained hand surgeons, twice, 4 weeks apart. The reviewers calculated trapezial space ratios, using three different methods, two previously described and a novel one: (1) trapezial space relative to first metacarpal length (classic 1); (2) trapezial space relative to proximal phalanx length (classic 2); and (3) trapezial space relative to capitate height (novel). Inter- and intraobserver reliabilities were measured using intraclass correlation coefficients (ICC) and limits of agreement for each method. RESULTS: The authors identified excellent agreement between the classic 1, classic 2, and novel methods with an ICC greater than 0.8, indicating excellent agreement. The average trapezial space ratios for the thumb proximal phalanx, thumb metacarpal, and capitate methods were measured as 0.19, 0.12, and 0.24, respectively. The upper and lower limits of the 95% confidence intervals for both the inter- and intraobserver agreements of the aforementioned trapezial space ratios were (0.17-0.26), (0.11-0.17), and (0.21-0.34) for the interobserver rates and (0.11-0.25), (0.06-0.16), and (0.12-0.33) for the intraobserver rates, respectively. CONCLUSION: Measuring trapezial space is an important diagnostic tool to assess postoperative changes in thumb length. The trapezial space indexed to the capitate height method (novel) provides a simple and similarly reliable method for calculating the trapezial space ratio on a PA radiograph of the hand/wrist when other measurement techniques are unavailable and when the thumb metacarpal or proximal phalanx is not intact. The authors found a high degree of reproducibility and inter- and intraobserver reliability as measured by the ICC and the 95% limits of agreement that compare with previous agreements in the literature.

Thumb Basal Joint Arthroplasty: Prospective Comparison of Perioperative Analgesia and Opioid Consumption.

Trapeziectomy alone or in combination with a suspensionplasty technique is a common surgical treatment for symptomatic thumb basal joint arthritis. The authors undertook a prospective comparative study to test the hypothesis that peripheral nerve blocks would provide better pain control than local anesthesia with bupivacaine or liposomal bupivacaine regarding pain scores and opioid pill consumption. Patients who elected to undergo basal joint arthroplasty were allocated to 1 of 3 postoperative pain management groups: (1) peripheral nerve block, (2) local anesthesia with bupivacaine, or (3) local anesthesia with liposomal bupivacaine. Total opioid pill consumption and visual analog scale pain scores were reported for the first 5 postoperative days (PODs). Seventy-eight patients were enrolled, with 27, 23, and 28 patients in the peripheral nerve block, bupivacaine, and liposomal bupivacaine groups, respectively. All groups experienced an increase in opioid pill consumption and visual analog scale pain scores from POD 0 to POD 1. Postoperative visual analog scale pain scores were lowest in group 3 from POD 0 to POD 2. Average visual analog scale pain scores were highest in group 1, except for on POD 0. After POD 2, visual analog scale pain scores normalized between all groups and decreased uniformly thereafter. Total opioid consumption was lowest in group 3 (average, 11 pills) compared with group 1 (average, 17 pills) and group 2 (average, 19 pills). Overall, these findings did not support the authors' hypothesis that peripheral nerve blocks are superior in terms of postoperative pain control and opioid consumption. Although there were advantages regarding opioid consumption and pain control with liposomal bupivacaine, these were limited to the first POD. The effectiveness of each modality, as well as potential risks and costs, should be considered when determining the optimal strategy. [Orthopedics. 2018; 41(3):e410-e415.].

Mini C-Arm Fluoroscopy: Does Its Configuration Matter for Radiation Exposure to the Surgeon?

BACKGROUND: The risk of occupational radiation exposure to the surgeon associated with the use of a mini C-arm has yet to reach a wide consensus. Using a distal radius fracture surgery model, we tested the hypothesis that radiation exposure to the surgeon's critical body parts is independent of mini C-arm configuration. METHODS: An anthropomorphic mannequin (representing the upper body of a 60" male surgeon) was seated at a hand table as if operating on a volar-plated wrist Sawbone model. Thermoluminescent dosimeters measured radiation exposure to the surgeon's eyes, thyroid, chest, hand, and groin from a mini C-arm fluoroscopy unit in 3 commonly used configurations: vertical (source above table), inverted (source below table), and horizontal (with beam parallel to table surface). The fluoroscope scanned the wrist model for 15 continuous minutes in triplicate for each orientation. RESULTS: Radiation to the hand was significantly greatest in all mini C-arm positions compared with all other anatomic sites irrespective of C-arm position. Hand radiation exposure was greatest in the horizontal position (2887.09 mrem), versus the vertical and inverted positions (59.79 mrem, 31.10 mrem, P < .001). Eye radiation exposure was significantly greater in the inverted position (2.33 mrem) compared with the vertical (0.67 mrem, P = .024), and horizontal positions (0.33 mrem, P = .012). No significant difference in radiation exposure was found at the thyroid, chest, and groin sites, at each of the 3 C-arm configurations. CONCLUSIONS: The model's hand received almost 1000 times more radiation exposure than all other anatomic sites with statistically greatest radiation exposure sustained in the horizontal position. Eye radiation exposure with the C-arm in the inverted position (below the table) was also significantly greater.