Following total hip arthroplasty: femoral head component diameter of 32 mm or larger is associated with lower risk of dislocation in patients with a prior lumbar fusion

Aims There is evidence that prior lumbar fusion increases the risk of dislocation and revision after total hip arthroplasty (THA). The relationship between prior lumbar fusion and the effect of femoral head diameter on THA dislocation has not been investigated. We examined the relationship between prior lumbar fusion or discectomy and the risk of dislocation or revision after THA. We also examined the effect of femoral head component diameter on the risk of dislocation or revision. Methods Data used in this study were compiled from several Finnish national health registers, including the Finnish Arthroplasty Register (FAR) which was the primary source for prosthesis-related data. Other registers used in this study included the Finnish Health Care Register (HILMO), the Social Insurance Institutions (SII) registers, and Statistics Finland. The study was conducted as a prospective retrospective cohort study. Cox proportional hazards regression and Kaplan-Meier survival analysis were used for analysis. Results Prior lumbar fusion surgery was associated with increased risk of prosthetic dislocation (hazard ratio (HR) = 2.393, p < 0.001) and revision (HR = 1.528, p < 0.001). Head components larger than 28 mm were associated with lower dislocation rates compared to the 28 mm head (32 mm: HR = 0.712, p < 0.001; 36 mm: HR = 0.700, p < 0.001; 38 mm: HR = 0.808, p < 0.140; and 40 mm: HR = 0.421, p < 0.001). Heads of 38 mm (HR = 1.288, p < 0.001) and 40 mm (HR = 1.367, p < 0.001) had increased risk of revision compared to the 28 mm head. Conclusion Lumbar fusion surgery was associated with higher rate of hip prosthesis dislocation and higher risk of revision surgery. Femoral head component of 32 mm (or larger) associates with lower risk of dislocation in patients with previous lumbar fusion. Cite this article: Bone Joint J 2020;102-B(8):1003–1009.

Recursively Binary Modification Model for Nested Named Entity Recognition

Recently, there has been an increasing interest in identifying named entities with nested structures. Existing models only make independent typing decisions on the entire entity span while ignoring strong modification relations between sub-entity types. In this paper, we present a novel Recursively Binary Modification model for nested named entity recognition. Our model utilizes the modification relations among sub-entities types to infer the head component on top of a Bayesian framework and uses entity head as a strong evidence to determine the type of the entity span. The process is recursive, allowing lower-level entities to help better model those on the outer-level. To the best of our knowledge, our work is the first effort that uses modification relation in nested NER task. Extensive experiments on four benchmark datasets demonstrate that our model outperforms state-of-the-art models in nested NER tasks, and delivers competitive results with state-of-the-art models in flat NER task, without relying on any extra annotations or NLP tools.

Russian Phraseological Units with the Somatic Component “Head” in Comparison with the Persian Language

Language and culture are closely interlinked and learning a foreign language is impossible without contact with the culture of the language being studied. Idioms play an important role in recognizing and deeply understanding the cultural peculiarities of different peoples. The article analyzes the ways phraseological units can be expressed in Persian, based on 175 collected idioms with the somatic component “head”. The novelty of the work is that until now this topic has not been studied in the comparative Russian-Persian aspect. The research shows that in most cases Russian phraseological units with the «head» component have a full equivalent in the Persian language, i.e. they are transmitted by means of phraseologisms with somatism “سر” [sar].

Comparison of Radial Head Resection With Radial Head Fixation in the Terrible Triad Injury of the Elbow

Background: The optimal treatment of radial head component in the terrible triad injuries of the elbow is challenging. In this study, we compared the functional outcome and complication rates of radial head resection with radial head fixation in a terrible triad setting. Objectives: Comparison of radial head resection with radial head fixation in terrible triad. Methods: In the present retrospective study, the outcome of terrible triad injury in 41 patients, in whom the radial head component was managed with either radial head resection (n=28) or open reduction and internal fixation (n=13), was compared. The subjective assessments of the outcome included visual analog scale (VAS) for pain, ‎the Mayo elbow performance score (MEPS), and the disabilities of the arm, shoulder, and ‎hand (DASH) score. The objective assessment of outcome included the evaluation of elbow range of motion (ROM) and elbow stability. Results: The mean±SD age of the patients was 39.2±10.2 years. The demographic characteristics of the patients of the two study groups were not statistically different. The mean supination/pronation arc of motion was not significantly different between the two ‏study groups (P=0.11). The mean flexion/extension arc of motion was significantly more in the fixation group (P=0.001). The mean MEPS and DASH scores were not ‏significantly different between the study groups (P=0.22 and P=0.49, respectively). The mean ‏VAS was significantly more in the fixation group (P=0.04). All the elbows were stable at the last follow-up. The postoperative complications (arthrosis and heterotopic ossification) were considerably more in the resection group. Conclusion: Although comparable at function, the present study favors the radial head fixation whenever possible to avoid the postoperative complications of radial head reaction.

Elevated Lip Liner Positions Improving Stability in Total Hip Arthroplasty – An Experimental Study

Background: The use of elevated lip polyethylene liners with the acetabular component is relatively common in Total Hip Arthroplasty (THA). Elevated lip liners increase stability of the THA by increasing the jump distance in one direction. However, the elevated lip, conversely, also reduces the primary arc in the opposite direction and leads to early impingement of the neck on the elevated lip, potentially causing instability. The aim of the present study is to determine the total range of motion of the femoral head component within the acetabular component with the elevated lip liner in different orientations within the acetabular cup.Methods: We introduce a novel experimental (ex-vivo) framework for studying the effects lip liner orientation on the range of motion of the femoral component. For constant acetabular cup orientation, the elevated lip liner was positioned superiorly and inferiorly. The femoral component range of motion in the coronal, sagittal and axial plane was measured. To avoid any confounding influences of out of plane motion, the femoral component was constrained to move in the tested plane.Results: This experimental set up introduces a rigorous framework in which to test the effects of elevated lip liner orientations on the range of motion of the femoral head component in abduction, adduction, flexion, extension and rotation. The movements of this experimental set-up are directly informative of patient’s maximum potential post-operative range of motion. Initial results show that an inferior placement of the elevated lip increases the effective superior lateral range of motion (abduction) for the femoral component, whilst the anatomy of the patient (i.e. their other leg) prevents the point of femoral component – acetabular lip impingement being reached (in adduction).