Perilunate Dislocations: Cadaveric Model K-Wire Versus Compression Staple Fixation.

Purpose: Repair of perilunate dislocations requires stabilization of the carpal bones, although there is limited research on the preferred method(s) of stabilization. We compared the biomechanical characteristics of K-wire versus staple fixation of scapholunate (SL) and lunotriquetral (LT) intervals in the wrist. Methods: After creating a grade IV instability model, 20 cadaver wrists were randomized into 2 stabilization model groups using K-wires or surgical staples across the SL and LT intervals. For each ligament, two K-wires or one surgical staple was used to stabilize the proximal carpal row. Each wrist was loaded with 15 N of force and cycled 5,000 times at an angular velocity of 10 rpm. Displacement between bones was measured at different cycles (10, 100, 500, 1,000, 2,000, 3,000, 4,000, and 5,000). A t test was used for comparisons. Results: For the LT K-wire group, the average displacement at 10 cycles was 0.08 mm, and at 5,000 cycles, 0.163 mm. For the SL K-wire group, the average displacement at 10 cycles was 0.025 mm, and at 5,000 cycles, 0.129 mm. For the LT and SL staple fixation models, the average shifts at 10 cycles were 0.029 and 0.063 mm, and at 5,000 cycles, 0.098 and 0.176 mm, respectively. No significant difference between the fixation models was found at any interval. Notably, in each group, a similar number of small outliers with higher amounts of displacement was observed. Conclusions: Either K-wire or surgical staple stabilization is suitable for perilunate dislocations. The surgical method should be selected based on patient-specific circumstances and the provider's judgment. Type of study/level of evidence: Therapeutic III.

Distal Upper Extremity Arterial Calcification as a Predictor for Subclinical Coronary Artery Disease by Coronary Artery Calcium Scoring.

Several studies have linked calcification of the thoracic and lower extremity arterial trunks to an increased risk of developing coronary artery disease (CAD). Calcifications of the radial and/or ulnar artery are regularly identified in hand/wrist x-rays; however, the clinical relevance of these findings as related to identifying subclinical CAD is not well understood. Associations between CAD and upper extremity calcifications have been reported, but the timeline is unclear. The purpose of this study was to evaluate the association between upper extremity arterial calcifications on hand radiographs with CAD by coronary artery calcification (CAC) scoring in patients with no known history of CAD. This is a pilot single-center, prospective, matched cohort study. We included patients with no known history of CAD, related symptoms, or major risk factors. We recruited five patients with calcifications (cal+) and five patients matched by age, race, sex, and medical history but without calcifications (cal-). CAC scores were determined from computed tomography scanning, and lipid profile was evaluated. In the cal+ group, the mean CAC total score was 244.1; in the control (cal-) group, it was 85.2. The mean total cholesterol levels were 220.8 mg per dL and 167 mg per dL in the cal+ and cal- groups, respectively. Two cal+ patients with CAC scores of 937 and 669 died shortly after being enrolled in our study. Preliminary findings suggest that calcifications in the radial or ulnar artery in otherwise asymptomatic patients with no history of CAD may be an independent sign of CAD.

Performance of Near-Infrared Spectroscopy in Detecting Acute Tourniquet-Induced Upper-Extremity Ischemia Across Different Skin Phenotypes.

PURPOSE: Diagnosing acute tissue ischemia is challenging, particularly in patients with higher skin melanin content. We investigated whether near-infrared spectroscopy (NIRS) is effective and consistent in detecting upper extremity ischemia across various skin phenotypes. METHODS: Volunteers underwent tourniquet-induced upper extremity ischemia. Skin color was evaluated by the Fitzpatrick scale (FP, range: I-VI) and the Von Luschan scale (vL, range: 1-36). A NIRS probe was placed on one finger. The tourniquet was inflated to 250 mmHg and perfusion was restricted for 7 minutes, followed by a 10-minute monitored reperfusion period. The percent tissue oxygenation (StO2) was recorded. RESULTS: A total of 55 volunteers were enrolled (22 self-identified as Caucasian, 21 African American, 7 Asian, 2 Latinx, and 2 Biracial). Average starting and ending StO2 for the cohort was 72.2% and 45.9%, respectively. However, there was variability based on skin melanin content. Increasing vL correlated with lower starting StO2, smaller StO2 decrease, and shorter time to reach ischemic steady state. High skin melanin (FP scale IV-VI) was associated with significantly lower starting StO2 (-7.1%) and shorter time to reach ischemic steady state (-0.3 mins). African Americans had lower starting StO2 (-8.6%) and 7.8% lesser total StO2 decrease than other groups. CONCLUSIONS: NIRS can rapidly detect acute onset tissue ischemia in the upper extremity. However, given the lower starting StO2 and smaller total StO2 decrease after tourniquet-induced ischemia for patients with higher skin melanin, using NIRS for clinical detection of acute ischemia may be more challenging in these patients. These inconsistencies may limit use of NIRS clinically for spot identification of ischemia. CLINICAL RELEVANCE: Although NIRS has utility in tracking tissue oxygenation, variable performance with different skin melanin content raises concerns as to whether different cutoff/threshold levels are needed for different groups, and whether NIRS is reliable for spot checks in acute events.

Assessing Hand Perfusion With Eulerian Video Magnification and Waveform Extraction.

PURPOSE: Timely and accurate triage of upper extremity injuries is critical, but current perfusion monitoring technologies have shortcomings. These limitations are especially pronounced in patients with darker skin tones. This pilot study evaluates a Eulerian Video Magnification (EVM) algorithm combined with color channel waveform extraction to enable video-based measurement of hand and finger perfusion. METHODS: Videos of 10 volunteer study participants with Fitzpatrick skin types III-VI were taken in a controlled environment during normal perfusion and tourniquet-induced ischemia. Videos were EVM processed, and red/green/blue color channel characteristics were extracted to produce waveforms. These videos were assessed by surgeons with a range of expertise in hand injuries. The videos were randomized and presented in 1 of 3 ways: unprocessed, EVM processed, and EVM with waveform output (EVM+waveform). Survey respondents indicated whether the video showed an ischemic or perfused hand or if they were unable to tell. We used group comparisons to evaluate response accuracy across video types, skin tones, and respondent groups. RESULTS: Of the 51 providers to whom the surveys were sent, 25 (49%) completed them. Using the Pearson χ2 test, the frequencies of correct responses were significantly higher in the EVM+waveform category than in the unprocessed or EVM videos. Additionally, the agreement was higher among responses to the EVM+waveform questions than among responses to the unprocessed or EVM processed. The accuracy and agreement from the EVM+waveform group were consistent across all skin pigmentations evaluated. CONCLUSIONS: Video-based EVM processing combined with waveform extraction from color channels improved the surgeon's ability to identify tourniquet-induced finger ischemia via video across all skin types tested. CLINICAL RELEVANCE: Eulerian Video Magnification with waveform extraction improved the assessment of perfusion in the distal upper extremity and has potential future applications, including triage, postsurgery vascular assessment, and telemedicine.