In Vivo Ultrasound Shear Wave Elastography Assessment of Acute Compartment Syndrome in a Turkey Model.

OBJECTIVE: The aim of the work described here was to evaluate the objectivity and reproducibility of non-invasive intra-compartment pressure (ICP) measurement using ultrasound shear wave elastography (SWE) in a turkey model in vivo and to determine the biological and histologic changes in acute compartment syndrome (ACS). METHODS: Twenty-four turkeys were randomly divided into four groups based on the duration and fasciotomy of ACS created by infusion of up to 50 mm Hg in the tibialis muscle: group 1, ACS 2 h; group 2, ACS 4 h; group 3, ACS 2 h + fasciotomy 2 h; group 4, ACS 4 h + fasciotomy 2 h. For each turkey, the contralateral limb was considered the control. Time-synchronized measures of SWE and ICP from each leg were collected. Then turkeys were euthanized for histology and quantitative reverse transcription polymerase chain reaction (qRT-PCR) examination. RESULTS: All models created reproducible increases in ICP and SWE, which had a strong linear relationship (r = 0.802, p < 0.0001) during phase 1. SWE remained stable (50.86 ± 9.64 kPa) when ICP remained at 50.28 ± 2.17 mm Hg in phase 2. After fasciotomy, SWE declined stepwise and then normalized (r = 0.737, p < 0.0001). Histologically, the myofiber diameter of group 2 (82.31 ± 22.92 µm) and group 4 (90.90 ± 20.48 µm) decreased significantly (p < 0.01) compared with that of the control group (103.1 ± 20.39 µm); the interstitial space of all groups increased significantly (p < 0.01). Multifocal muscle damage revealed neutrophilic infiltration, degeneration, hemorrhage and necrosis, especially in group 4. Quantitative RT-PCR verified that interleukin-6 and heparin-binding EGF-like growth factor were significantly increased in group 4. CONCLUSION: SWE provided sensitive measurements correlating to ICP in a clinically relevant ACS animal model. Once ACS time was exceeded, progression to irreversible necrosis continued spontaneously, even after fasciotomy. SWE may help surgeons in the early detection, monitoring, prognosis and decision making on fasciotomy for ACS.

Assessment of malalignment at the metacarpophalangeal joint of the rheumatoid hand using three-dimensional computed tomogram.

OBJECTIVE: For the assessment of rheumatoid hand, three-dimensional (3D) malalignment including flexed or rotational deformities and dislocation at the finger joint is one of the important findings. The objective of this study is to prove usefulness of 3D computed tomography (3DCT) for the accurate measurement of palmoulnar flexion deformity at the metacarpophalangeal (MP) joint of the rheumatoid hand. METHODS: Swanson implant arthroplasty at the 2nd through the 5th MP joints was performed at 179 joints in 46 hands of 40 patients with rheumatoid arthritis. Pre-and postoperatively, evaluations included Larsen grade and ulnar flexion angle by an x-ray; and ulnar flexion angle, palmar flexion angle, and resected bone length by a 3DCT. RESULTS: With progression of Larsen grade and the joint dislocation, ulnar flexion angle increased. Average ulnar flexion angle was 18.7 ± 16.0° (mean ± SD) in grade III, 38.4 ± 21.2° in grade IV, and 40.1 ± 21.1° in grade V, 29.6 ± 16.0°in "subluxation," 24.8 ± 21.2° in "dislocation," and 41.1 ± 22.2° in "severe dislocation." There was no significant difference between grade of the MP joint dislocation and palmar flexion angle. With progression of the MP joint dislocation, resected bone length increased. CONCLUSION: A 3DCT gives accurate information about deformity of the rheumatoid hand. Also, an appropriate length of bone resection can be determined in the preoperative planning.