Spectral CT imaging of human osteoarthritic cartilage via quantitative assessment of glycosaminoglycan content using multiple contrast agents.

Detection of early osteoarthritis to stabilize or reverse the damage to articular cartilage would improve patient function, reduce disability, and limit the need for joint replacement. In this study, we investigated nondestructive photon-processing spectral computed tomography (CT) for the quantitative measurement of the glycosaminoglycan (GAG) content compared to destructive histological and biochemical assay techniques in normal and osteoarthritic tissues. Cartilage-bone cores from healthy bovine stifles were incubated in 50% ioxaglate (Hexabrix®) or 100% gadobenate dimeglumine (MultiHance®). A photon-processing spectral CT (MARS) scanner with a CdTe-Medipix3RX detector imaged samples. Calibration phantoms of ioxaglate and gadobenate dimeglumine were used to determine iodine and gadolinium concentrations from photon-processing spectral CT images to correlate with the GAG content measured using a dimethylmethylene blue assay. The zonal distribution of GAG was compared between photon-processing spectral CT images and histological sections. Furthermore, discrimination and quantification of GAG in osteoarthritic human tibial plateau tissue using the same contrast agents were demonstrated. Contrast agent concentrations were inversely related to the GAG content. The GAG concentration increased from 25 µg/ml (85 mg/ml iodine or 43 mg/ml gadolinium) in the superficial layer to 75 µg/ml (65 mg/ml iodine or 37 mg/ml gadolinium) in the deep layer of healthy bovine cartilage. Deep zone articular cartilage could be distinguished from subchondral bone by utilizing the material decomposition technique. Photon-processing spectral CT images correlated with histological sections in healthy and osteoarthritic tissues. Post-imaging material decomposition was able to quantify the GAG content and distribution throughout healthy and osteoarthritic cartilage using Hexabrix® and MultiHance® while differentiating the underlying subchondral bone.

Spontaneous Spinal Epidural Hematomas in Pregnancy: A Systematic Review.

BACKGROUND: Spontaneous spinal epidural hematomas (SSEH) are rare yet severe conditions. In pregnancy, this condition is challenging to diagnose and treat because of the risks to the mother and fetus. This study reviews the literature on SSEHs in pregnancy. METHODS: We performed a systematic review of the English literature on SSEHs from 1990 until 2018. Outcome measures were mode of presentation, risk factors, initial neurologic findings, diagnostic investigations, site and size of the SSEH, treatment, neurologic recovery, and survival. RESULTS: Fourteen publications (16 patients) were included. Two patients presented in the second trimester, with the remainder in the third trimester. All patients presented with back pain, and 15 subsequently developed spinal cord dysfunction. Magnetic resonance imaging (MRI) was performed in all cases. The cervicothoracic region was the most commonly affected, and the average hematoma size extended across 3.9 vertebral levels. All patients with neurologic dysfunction underwent surgical decompression. In women under 32 weeks' gestation, caesarean section was not routinely performed. In contrast, women of gestational age of 32 weeks or more underwent a caesarean section prior to spinal decompression. Women without neurologic dysfunction underwent a caesarean section and neurologic monitoring without decompression. All patients with abnormal neurology improved after surgery, except 1 patient. No patients died. CONCLUSIONS: In pregnancy, SSEHs typically present in the second or third trimesters with back pain, predominantly in the cervicothoracic region, followed by progressive neurologic dysfunction. MRI is diagnostic, and the treatment depends on the patient's neurologic dysfunction and gestational age.

The use of an Ossis custom 3D-printed tri-flanged acetabular implant for major bone loss: minimum 2-year follow-up.

INTRODUCTION: Custom 3D-printed acetabular implants are a new technology used in hip surgery with ever-increasing frequency. They offer patient-specific implants to optimise filling of bone defects and implant-bone contact, without the need for excessive bone resection. METHODS: This is a retrospective cohort study of 46 consecutive patients who underwent an Ossis unilateral custom 3D-printed acetabular implant. Clinical (Oxford Hip Score OHS-60), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Harris Hip Score (HHS) and radiological (restoration of biomechanical hip centre, osteointegration, wear, heterotrophic ossification) results were assessed. RESULTS: Patient mean age was 68 years and follow-up was 38 months (minimum 24 months). 10 patients were excluded from the outcome analysis; 2 patients died, 1 required revision for deep infection and 7 were lost to follow-up. Of the 36 patients included, 21 had severe osteolysis. 7 were revised for infection, 3 for tumoural defects, 3 for metallosis, 1 for dysplasia and 1 for trauma (Paprosky 2a [n=6], 2b [n=2], 2c [n=5], 3a [n=6], 3b [n=11], pelvic dissociation [n=6]). OHS significantly improved postoperatively (16-8-48.4 p=0.027). Postoperative functional scores were good (WOMAC 98; HHS 79). The biomechanical hip centre was restored in all patients. 1 patient had early implant migration with subsequent stabilisation. 2 patients had radiographs concerning for failure of osteointegration. 1 patient had recurrent dislocations. CONCLUSIONS: The mid-term results of the Ossis custom 3D-printed tri-flanged acetabular implant for the management of severe acetabular defects are encouraging. The improvement in functional scores and radiographic outcomes are comparable to similar designs. In addition, no cases have required revision for aseptic loosening.