Time-dependent changes of insufficiency fractures of the sacrum: intraosseous vacuum phenomenon as an early sign

Sacral insufficiency fractures develop over a period of time and show time-dependent changes. We report on 15 CT examinations of 5 patients with early-stage insufficiency fractures of the sacrum. In 4 patients only irregular sclerosis without distinct fracture lines was present in 7 of 8 fractures. Of these 4 patients; 3 exhibited intraosseous gas inclusions in a ventral part of a lateral mass; 5 of 8 fractures disclosed a ventral cortical break. When distinct fracture lines had developed in 1 patient, intraosseous vacuum phenomenon had disappeared. Fracture lines evolve over weeks to months and show central bone absorption. The fractures can heal as demonstrated in 4 of 6 fractures in 3 patients, can persist over 1 year without significant changes or can progress to pseudoarthrosis with bone destruction similar to neuropathic joint disease. Intraosseous vacuum phenomena can persist to this stage. Intraosseous vacuum phenomenon is recognized as a potential finding in the early stage of sacral insufficiency fracture, which also is true for irregular sclerosis and ventral cortical disruption. Correspondence to: A. Stäbler     

Comparison of the biomechanical effect of posterior condylar offset and kinematics between posterior cruciate-retaining and posterior-stabilized total knee arthroplasty

Background

The effect of the changes in the femoral posterior condylar offset (PCO) on anterior–posterior (AP) translation and internal–external (IE) rotation in cruciate-retaining (CR) and posterior-stabilized (PS) total knee arthroplasty (TKA) remains unknown. The purpose of this study was to compare the kinematics in CR and PS TKA with respect to the difference in prosthetic design and PCO change through a computational simulation.

Computed tomographic study of the posterior condylar angle in arthritic knees: its use in the rotational positioning of the femoral implant of total knee prostheses

The epicondylar axis is a reliable reference to check the rotation of the femoral implant in total knee prostheses (TKPs). However, during the operation it seems easier to use the posterior condylar axis as a landmark. The angle between these two axes is called the posterior condylar angle (PCA). The aim of this study was to measure the PCA in arthritic knees to assess the reliability of the posterior condylar axis as a reference for the control of the rotation of the femoral implant and to look for correlation with other radiological measurements. This prospective study consisted of 103 arthritic knees (81 varus, 22 valgus) before a TKP had been done in 103 patients (75 women, 28 men). The assessment of the PCA was made by computed tomographic scanning (CT). The HKA, HKS and HKT angles were measured on the pangonogram. The posterior condylar axis was internally rotated with respect to the epicondylar axis. The average value for all the patients was 2.65° degrees with a range from 0° to 7°. The PCA was significantly increased in the valgus knees. There was no correlation between the angles on the pangonogram and the posterior condylar axis. While the preoperative assessment of the PCA by CT scanning is reliable, the results obtained indicate the marked variability in its value. If one wishes to use the posterior condylar axis as a guide for rotation, it is therefore necessary to assess the PCA for each patient using adjustable jigs according to the value obtained. No measurement on standard radiographs allowed an extrapolation of the value of the PCA, and CT scanning seems to be the preferable radiological examination.

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Electronic Supplementary Material The french version of this article is available in the form of electronic supplementary material and can be obtained by using the Springer Link server located at

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Etude tomodensitométrique de l'angle condylien postérieur dans les genoux arthrosiques. Intérêt dans le positionnement en rotation de l'implant fémoral dans les prothèses totales de genou

Résumé L'axe épicondylien est une référence fiable pour le contrôle de la rotation de l'implant fémoral dans les prothèses totales de genou (PTG). Mais, lors de l'intervention, il semble plus facile d'utiliser l'axe condylien postérieur comme repère. L'angle entre ses deux axes est appelé angle condylien postérieur (ACP). Le but de cette étude était de mesurer l'ACP dans les genoux arthrosiques, d'évaluer la fiabilité de l'axe condylien postérieur comme référence pour le réglage de la rotation de l'implant fémoral, de rechercher une corrélation avec d'autres mesures radiologiques. Une étude prospective comportant 103 genoux arthrosiques (81 varus et 22 valgus), avant PTG a été effectuée, chez 103 patients (75 femmes et 28 hommes). L'évaluation de l'ACP a été faite par examen tomodensitométrique (TDM). Les angles HKA, HKS et HKT ont été mesurés sur le pangonogramme. L'axe condylien postérieur était en rotation interne par rapport à l'axe épicondylien. La valeur moyenne pour tous les patients était de 2.65°, avec des valeurs de 0 à 7°. La valeur de l'angle CP augmentait avec une différence significative dans le groupe des genu valgum. Il n'y avait pas de corrélation entre les angles du pangonogramme et l'ACP. Si l'évaluation pré-opératoire de l'ACP par TDM est fiable, les résultats obtenus mettent en évidence une variabilité importante de sa valeur. Il faut donc, si l'on veut utiliser l'axe condylien postérieur comme repère de rotation, évaluer pour chaque patient l'ACP, et utiliser un ancillaire réglable reportant la valeur obtenue. Aucune mesure sur des radiographies standard ne permettant d'extrapoler la valeur de l'ACP, la TDM semble l'examen radiologique de choix.

     

A case of broken bones and systems: The threat of irresponsible testimony

A 2‐month‐old healthy baby presented to the emergency room with an arm that was not moving and was found to have multiple and extensive fractures of her long bones. An extensive medical work‐up was done, and the hospital's multidisciplinary child abuse team was consulted, including child protection, genetics, radiology, and general pediatrics. It was determined that the history, clinical findings, radiographic findings, and laboratory findings were consistent with child abuse. Child protection services removed the child from the home, and for the next 10 months, the infant was well, and did not sustain a single new fracture. At a civil proceeding to determine the infant's custody, an expert witness for the defense concluded that the child had hypermobile Ehlers‐Danlos syndrome and low vitamin D. He stated that because of these conditions, the baby was vulnerable to fractures with routine handling. This is a personal story of a clinical geneticist who explored fracture fact versus fracture fiction and learned about the difference between responsible and irresponsible testimony. This story gives insight into how physicians can prepare to transition from the clinic to the courtroom. It is also a story about how medical experts must and should remain unbiased, evidence‐based, and committed to accuracy and truth.     

肩胛骨前后联合入路治疗陈旧性浮肩损伤（附6例报告）

目的：探讨肩胛骨前后联合入路治疗陈旧性浮肩损伤的临床疗效。方法：采用肩胛骨前后联合入路对6例陈旧性浮肩损伤进行手术治疗。结果：根据Herscovici功能评估标准，其中优1例，良2例，可3例，无血管神经副损伤。结论：采用肩胛骨前后联合入路处理陈旧性浮肩损伤，术野显露清楚，易于操作与复位固定，可以有效地避开血管神经，安全可靠。     

Source of the slippage in the universal joints of the Hoffmann external fixator

An investigation was conducted to determine what improvements in the resistance to slippage could be obtained in selected interfaces (rod/clip torsional, cheek/bowl and cheek/clip) of the Hoffmann external fixator. The modification involved changing the standard wing-nut clamp for a bolt with a thread of 7 mm and a 1 mm pitch and placing an FAG 28–303 thrust-bearing (needle roller and cage assembly) between the bolt and the cheek. The results showed a significant improvement in the slippage values of all interfaces; increases of approximately six times were obtained at all torque values of the wing-nut clamp or fastener tested. Such improvements would markedly increase the reliability of external fixation systems and thus reduce the incidence of loss-of-reduction of fracture due to slippage of the universal joint.     

The functional anatomy of the human anterior talofibular ligament in relation to ankle sprains

The anterior talofibular ligament is the most commonly injured ligament in the ankle. Despite considerable interest in the clinical outcome of treatment protocols, we do not know whether the distinctive pattern of localization of the injuries relates to regional differences in the structure and molecular composition of the ligament. To address this issue, ligaments were examined by histology and immunohistochemistry. Differences in the structure of its two attachments (i.e. entheses) were evaluated with quantitative, morphometric techniques, and regional differences in the distribution of collagens, glycosaminoglycans and proteoglycans were determined qualitatively by immunolabelling. Morphometric analyses showed that bone density was less at the fibular attachment, but that enthesis fibrocartilage was more prominent. Immunohistochemistry revealed the presence of a fibrocartilage (containing type II collagen and aggrecan) at the site where the ligament wraps around the lateral talar articular cartilage in a plantarflexed and inverted foot: the fibrocartilage is regarded as an adaptation to resisting compression. We propose that avulsion fractures are less common at the talar end of the ligament because (1) bone density is greater here than at the fibular enthesis, and (2) stress is dissipated away from the talar enthesis by the 'wrap-around' fibrocartilaginous character of the ligament near the talar articular facet.     

Machine Learning Algorithms to Predict Mortality and Allocate Palliative Care for Older Patients With Hip Fracture

ObjectivesTo evaluate a machine learning model designed to predict mortality for Medicare beneficiaries aged >65 years treated for hip fracture in Inpatient Rehabilitation Facilities (IRFs).DesignRetrospective design/cohort analysis of Centers for Medicare & Medicaid Services Inpatient Rehabilitation Facility–Patient Assessment Instrument data.Setting and ParticipantsA total of 17,140 persons admitted to Medicare-certified IRFs in 2015 following hospitalization for hip fracture.MeasuresPatient characteristics include sociodemographic (age, gender, race, and social support) and clinical factors (functional status at admission, chronic conditions) and IRF length of stay. Outcomes were 30-day and 1-year all-cause mortality. We trained and evaluated 2 classification models, logistic regression and a multilayer perceptron (MLP), to predict the probability of 30-day and 1-year mortality and evaluated the calibration, discrimination, and precision of the models.ResultsFor 30-day mortality, MLP performed well [acc = 0.74, area under the receiver operating characteristic curve (AUROC) = 0.76, avg prec = 0.10, slope = 1.14] as did logistic regression (acc = 0.78, AUROC = 0.76, avg prec = 0.09, slope = 1.20). For 1-year mortality, the performances were similar for both MLP (acc = 0.68, AUROC = 0.75, avg prec = 0.32, slope = 0.96) and logistic regression (acc = 0.68, AUROC = 0.75, avg prec = 0.32, slope = 0.95).Conclusion and ImplicationsA scoring system based on logistic regression may be more feasible to run in current electronic medical records. But MLP models may reduce cognitive burden and increase ability to calibrate to local data, yielding clinical specificity in mortality prediction so that palliative care resources may be allocated more effectively.     

Comorbidity and Quality of In-Hospital Care for Hip Fracture Patients

ObjectivesWe examined whether the comorbidity burden of patients with hip fracture was associated with quality of in-hospital care reflected by fulfillment of process performance measures.DesignPopulation-based cohort study using prospectively collected data from the Danish Multidisciplinary Hip Fracture Registry (DMHFR).Setting and ParticipantsPatients aged 65 years or older with an incident hip fracture from 2014 to 2018 registered in the DMHFR (n = 31,443).MethodsComorbidity was measured using the Charlson Comorbidity Index based on hospital diagnoses. Quality of in-hospital care was defined as fulfillment of eligible process performance measures, including preoperative optimization, early surgery, early mobilization, pain assessment, basic mobility, nutritional risk, need for anti-osteoporotic medication, fall prevention, and a post-discharge rehabilitation program, reflecting guideline-recommended in-hospital care. The outcomes were (1) an all-or-none composite measure defined as fulfillment of all relevant process performance measures, and (2) fulfillment of the individual process performance measures. Using binary regression, we calculated relative risk (RR) for the association between comorbidity level and outcomes.ResultsThe overall proportion of patients with hip fracture who fulfilled the all-or-none measure was 31%. Among patients with no comorbidity, 34% fulfilled the all-or-none measure versus 29% among patients with high comorbidity (Charlson ≥ 3). This corresponds to a 15% lower chance (RR = 0.85, 95% confidence interval 0.81–0.89). Increasing comorbidity was also associated with lower fulfillment of the individual process performance measures. The largest difference was seen for preoperative optimization, early surgery, and early mobilization, where patients with high comorbidity had 6% to 11% lower chance of fulfillment of these process performance measures compared with patients without comorbidity.Conclusion and ImplicationsIncreasing level of comorbidity was associated with lower quality of in-hospital care among patients with hip fracture. Our results highlight the need for tailored clinical initiatives to ensure that comorbid patients also benefit from the positive progress in hip fracture care in recent years.     

多发伤的骨折内固定

目的：认识多发伤中骨折的主要特点,探讨内固定在救治中的意义。方法：回顾1994－08～1999－08间手术救治多发伤66例,对其161处骨折中的98处进行了“仿AO技术”有关方法内固定。结果：骨折均满意愈合;涉及骨折关节51个,功能恢复满意率为96．08％。结论：在多发伤中,骨折、合并伤与并发症远较“一般骨折”复杂、严重;有效固定骨折是一种重要的救命措施;内固定手术应争取在伤后24h进行,但如受条件制约,伤后1－3wk内手术也可获得满意效果;仿AO技术中的某些方法,如拉力螺钉、张力带钢丝及自动加压钢板等,用于内固定可使骨折获得卓有成效的稳定性。