25 research outputs found
Detecting mechanical loosening of total hip replacement implant from plain radiograph using deep convolutional neural network
Plain radiography is widely used to detect mechanical loosening of total hip
replacement (THR) implants. Currently, radiographs are assessed manually by
medical professionals, which may be prone to poor inter and intra observer
reliability and low accuracy. Furthermore, manual detection of mechanical
loosening of THR implants requires experienced clinicians who might not always
be readily available, potentially resulting in delayed diagnosis. In this
study, we present a novel, fully automatic and interpretable approach to detect
mechanical loosening of THR implants from plain radiographs using deep
convolutional neural network (CNN). We trained a CNN on 40 patients
anteroposterior hip x rays using five fold cross validation and compared its
performance with a high volume board certified orthopaedic surgeon (AFC). To
increase the confidence in the machine outcome, we also implemented saliency
maps to visualize where the CNN looked at to make a diagnosis. CNN outperformed
the orthopaedic surgeon in diagnosing mechanical loosening of THR implants
achieving significantly higher sensitively (0.94) than the orthopaedic surgeon
(0.53) with the same specificity (0.96). The saliency maps showed that the CNN
looked at clinically relevant features to make a diagnosis. Such CNNs can be
used for automatic radiologic assessment of mechanical loosening of THR
implants to supplement the practitioners decision making process, increasing
their diagnostic accuracy, and freeing them to engage in more patient centric
care
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Worse health-related quality of life and hip function in female patients with elevated chromium levels: A prospective study of 659 patients with a recalled THR metal-on-metal implant
Background and purpose Blood metal ion levels can be an indicator for detecting implant failure in metal-on-metal (MoM) hip arthroplasties. Little is known about the effect of bilateral MoM implants on metal ion levels and patient-reported outcomes. We compared unilateral patients and bilateral patients with either an ASR hip resurfacing (HR) or an ASR XL total hip replacement (THR) and investigated whether cobalt or chromium was associated with a broad spectrum of patient outcomes. Patients and methods From a registry of 1,328 patients enrolled in a multicenter prospective follow-up of the ASR Hip System, which was recalled in 2010, we analyzed data from 659 patients (311 HR, 348 THR) who met our inclusion criteria. Cobalt and chromium blood metal ion levels were measured and a 21-item patient-reported outcome measures (PROMs) questionnaire was used mean 6 years after index surgery. Results: Using a minimal threshold of ≥7 ppb, elevated chromium ion levels were found to be associated with worse health-related quality of life (HRQoL) (p < 0.05) and hip function (p < 0.05) in women. These associations were not observed in men. Patients with a unilateral ASR HR had lower levels of cobalt ions than bilateral ASR HR patients (p < 0.001) but similar levels of chromium ions (p = 0.09). Unilateral ASR XL THR patients had lower chromium and cobalt ion levels (p < 0.005) than bilateral ASR XL THR patients. Interpretation Chromium ion levels of ≥7 ppb were associated with reduced functional outcomes in female MoM patients