Search

Background: Periprosthetic femur fractures (PPFFs) following total hip arthroplasty (THA) have increased in the past decade as the demand for primary surgery continues to grow. Although there is now more evidence to describe the treatment of Vancouver B fractures, there is still limited knowledge regarding factors that cause surgeons to perform either an open reduction and internal fixation (ORIF) or revision THA (rTHA). The purpose of this study was to determine what type of surgeons treat Vancouver B PPFFs at 11 major academic institutions and if there are trends in treatment decision-making regarding the use of ORIF or rTHA based on surgical training or patient factors. Methods: This multicenter retrospective study evaluated patients surgically treated for Vancouver B PPFF after THA between 2014 and 2019. Patients from 11 academic centers located in the United States were included in this study. Surgical outcomes and patient demographics were evaluated based on surgeon training, surgical treatment type, and institution. Results: Presence of Vancouver B2 (odds ratio [OR]: 0.02, P < .001) or B3 (OR: 0.04, P < .001) fractures were independent risk factors for treatment with rTHA. Treatment by a trauma (OR: 12.49, P < .001) or other-specified surgeon (OR: 13.63, P < .001) were independent risk factors for ORIF repair of Vancouver B fractures. There were no differences in outcomes based on surgeon subspecialty training. Conclusions: This study showed the trends in surgeons who surgically manage Vancouver B fractures at 11 major academic institutions and highlighted that regardless of surgical training or surgical treatment type, postoperative outcomes following management of PPFF were similar.

Background: Application time and viscosity are factors that can significantly affect the properties of bone cement and implant fixation. The aim of this study was to investigate the influence of different application times of 2 different cements on mechanical parameters, cement interdigitation, and cement distribution. Methods: P.F.C. Sigma tibial trays were cemented with high-viscous Palacos R and medium- to low-viscous Simplex P in an open-cell model. The application was performed at different times within the manufacturer’s specifications. Cement interdigitation and micromotion were measured with computed tomography scan using a novel method. Results: Significant differences of insertion forces were found at all times of cement application. Cement penetration decreased with increasing pressure and viscosity. No significant differences were shown for micromotion between Palacos R and Simplex P except for an increase for Simplex P from 3 to 7 minutes at the bone-cement interface. Simplex P appeared to trap air at the implant-cement interface at 3 minutes and increased at 7 minutes. Conclusions: Cement distribution and intrusion of Palacos R and Simplex P decreased with time. Simplex P trapped air at the implant-cement interface, decreasing the amount of contact at the implant-cement interface, which is worrisome for long-term implant fixation. Given the significant changes in cement properties after mixing, it is necessary for surgeons to understand the viscosity and timing of cement application to achieve optimal cement penetration and surface contact area to potentially decrease implant loosening. High-viscous Palacos R should be applicated immediately with doughing time and medium-viscous Simplex P for about 4 minutes considering a threshold of minimum pressure.

Sternal fractures are rare and are typically caused by major trauma such as motor vehicle collisions. However, sternal insufficiency fractures can occur with minimal to no trauma in patients with exaggerated thoracic kyphosis from multiple thoracic compression fractures, especially in the setting of osteoporosis. We describe a case of a sternal insufficiency fracture that presented as chest pain resembling a myocardial infarction. As sternal insufficiency fractures may vary in clinical presentation, this case demonstrates that radiologists should carefully evaluate the sternum, especially when risk factors are present. Furthermore, awareness and identification of these fractures can prevent unnecessary cardiac workups.

Introduction: Aseptic tibial loosening following total knee arthroplasty (TKA) can be challenging to diagnose radiographically. Surgeons often face the clinical scenario of determining implant fixation in patients that do not have serial radiographs and only subtle radiographic features of loosening. Therefore, the purpose of our study was to determine how accurately attendings and trainees are at identifying aseptic tibial loosening. Methods: Two cohorts of patients were identified for this study. Cohort one consisted of twenty patients with aseptic tibial loosening. Cohort two consisted of twenty patients with well-fixed pain-free total knee replacements at one-year follow-up. Surgeons were then given a clinical scenario that all patients are returning with pain at follow-up. The surgeon then reviewed each patient's radiographs and determined whether the tibial component was loose or well-fixed. Results: Overall, surgeons were significantly more likely to correctly identify well-fixed implants than loose implants (p

Introduction: There has been a substantial shift in the number of outpatient total joint arthroplasty performed over the last decade. Furthermore, use of ambulatory surgical centers (ASC) has increased, which has led to improved access to operating rooms and increased efficiency for many arthroplasty surgeons. However, there remains uncertainty as to the safety of this rapid transition from inpatient to outpatient surgery especially at major medical centers usually associated with a more morbid population. Methods: Utilizing the total joint registry at our institution, we identified all total hip and knee arthroplasties from2018–2022 (n = 5000). Surgeries were grouped by timing of surgery, location and by admission status. Patient demographics and clinical outcomes were collected and compared with a focus on readmission and reoperation rates. Results: There was a significant increase in the percentage of same day surgery (SDS) total joint arthroplasty after the transition to an ASC. We identified no significant change in reoperation rate or 30-day readmission amongst SDS patients with our rapid transition to outpatient. Furthermore, the post-transition cohort had a higher incidence of diabetes were more medically complex and the patients were generally older. Conclusion: Within one year of the COVID-19 pandemic onset, we transitioned approximately half of our surgical volume from an inpatient hospital setting to a stand-alone ASC. Furthermore, we did not identify any statistical difference in reoperations, readmissions, or complications even amongst a higher risk population. Therefore, we found a rapid transition to ASC outpatient surgery to be a safe option.

Dislocation remains the leading cause of failure following revision total hip arthroplasty. Dual mobility (DM) constructs, including monoblock cups designed for cementation, reduce but do not eliminate this risk. Cemented DM constructs offer several unique advantages in revision total hip arthroplasty, and as such, they have gained popularity. Despite their advantages, a portion of these implants will require revision for infection or recurrent dislocation. Removal of a cemented DM cup presents numerous challenges, and there is no effective published technique. Here, we present an effective technique for the safe removal of one design of cemented DM cup.

Background: Prosthetic hip dislocation remains one of the most frequent complications following total hip replacement. Dislocations are predominantly managed by a closed reduction in the emergency department (ED) or the operating room (OR). This study aimed to evaluate how the location of an initial closed reduction attempt impacts a patient's course of care including length of stay (LOS) and cost of care. Material and methods: A retrospective chart review was performed on all patients presenting to a single ED with a unilateral prosthetic hip dislocation from 2009 to 2019. A total of 108 patients were identified. Data collected included patient demographics, ED/hospital course, and hospital charges. Results: Seventy-four patients (69%) had initial reduction attempted in the ED (65/74, 88% were successful), while 34 patients (31%) went directly to OR (100% successful with closed reduction). Failed closed reduction in ED or direct to OR resulted in a greater LOS and rate of placement to a skilled nursing facility following discharge. Median hospital charges for successful ED reduction were $6,837, while failed ED closed reduction or direct to OR resulted in median charges of $27,317 and $20,481, respectively. Conclusion: Many patients successfully underwent closed reduction in the ED, and there was no difference in complications, independent of where the reduction was first performed. Patients undergoing reduction in the OR had greater LOS and cost of care, independent of whether a reduction attempt was performed and failed in the ED, than those successfully reduced in the ED.

Alignment of picornavirus proteinase/polymerase sequences reveals this family evolved into five 'supergroups'. Interestingly, the nature of the 2A region of the picornavirus polyprotein is highly correlated with this phylogeny. Viruses within supergroup 4, the Paavivirinae, have complex 2A regions with many viruses encoding multiple 2ANPGP sequences. In vitro transcription/translation analyses of a synthetic polyprotein comprising green fluorescent protein (GFP) linked to β-glucuronidase (GUS) via individual 2ANPGPs showed two main phenotypes: highly active 2ANPGP sequences—similar to foot-and-mouth disease virus 2ANPGP—and, surprisingly, a novel phenotype of some 2ANPGP sequences which apparently terminate translation at the C-terminus of 2ANPGP without detectable re-initiation of downstream sequences (GUS). Probing databases with the short sequences between 2ANPGPs did not reveal any potential 'accessory' functions. The novel, highly active, 2A-like sequences we identified substantially expand the toolbox for biomedical/biotechnological co-expression applications. [ABSTRACT FROM AUTHOR]

Background: Dexamethasone has the potential to cause a transient increase in blood glucose levels. Recent evidence has suggested the potential for a linearly increased risk of periprosthetic joint infection beginning at blood glucose levels of ≥115 mg/dL and an optimal cutoff of 137 mg/dL. We designed the following study to determine (1) what percentage of our patients had postoperative day 1 (POD1) glucose levels above 137 mg/dL and (2) if the administration of dexamethasone further increased this risk. Methods: All primary total knee arthroplasties performed from 1998 to 2021 at our institution were identified and retrospectively reviewed. Patient demographics, dexamethasone administration, and perioperative glucose levels were recorded. Outcomes included POD1 glucose levels, infection rate, and all-cause reoperations and revisions. Results: The average POD1 glucose level for the entire cohort (n = 5353) was 138.7 mg/dL. The percentage of patients with a glucose level of 137 mg/dL or higher was significantly greater in patients that received dexamethasone (55.2% vs 37.7%; P < .0001). Significantly higher glucose levels were seen with dexamethasone administration in both diabetic (187.7 vs 173.4 mg/dL; P < .0001) and nondiabetic patients (137.7 vs 128.0 mg/dL; P < .0001). Dexamethasone use was associated with a nonstatistically significant increase in infection rates (1.7% vs 1.0%; P = .177). Conclusions: Administration of dexamethasone is associated with a statistically significant increase in POD1 glucose levels, regardless of diabetic status. Dexamethasone use should continue to be closely monitored given the potential risks of elevated postoperative glucose levels and the potential for periprosthetic infection.

Background: Total hip arthroplasty (THA) has demonstrated excellent results regardless of the surgical approach. However, the approach used may be a factor in final positioning of implants. We hypothesized that the direct anterior approach (DAA) with fluoroscopy would be associated with more anatomic implant positioning than the posterior approach (PA). Methods: A retrospective review of 200 patients was performed. One hundred patients underwent THA utilizing the PA, and 100 patients, with the DAA. All patients had an anterior-posterior pelvis radiograph preoperatively and postoperatively with a magnification marker present to standardize each radiograph. Exclusion criteria included contralateral THA or any pelvic or femoral deformity. Results: Preoperative radiographs demonstrated identical cohorts with respect to leg length, femoral offset, and total offset. Postoperatively, the DAA achieved more accurate anatomic restoration of leg length (1.6 mm vs 5.5 mm; P < .0001), femoral offset (4.8 mm vs 9.3 mm; P < .0001), and total offset (0.5 mm vs 4.7 mm; P < .0001) compared with the PA. Ideal cup abduction and anteversion were significantly superior to the DAA (96% vs 78%, P = .0002, and 69% vs 24%, P < .0001, respectively). Conclusions: This study is the first to compare anatomic implant positioning between patients undergoing THA with these 2 approaches. All parameters were significantly closer to anatomic implant positioning with the DAA. There are at least 2 potential explanations for this: (1) The DAA implant positioning was performed under fluoroscopic guidance, whereas the PA was not. (2) The PA disrupts the posterior capsule and external rotators, and therefore, increased offset or leg length may be necessary to achieve comparable hip stability with the DAA.

Background: In total hip arthroplasty (THA), component position is critical to avoid instability and improve longevity. Appropriate combined femoral and acetabular component anteversion is important for improved THA stability and increased impingement-free range of motion. In direct anterior THA (DA-THA), concern has been expressed regarding the accuracy of femoral component positioning. This study seeks to quantify acetabular, femoral, and combined component orientation relative to the accepted “safe zones” in patients who have undergone DA-THA. Methods: Twenty-nine patients who had THA performed via direct anterior approach had postoperative computerized tomography scans done to assess femoral anteversion. Stem rotational alignment was measured relative to the transepicondylar axis (TEA) and the posterior condylar axis (PCA) of the femur at the knee. Acetabular abduction and version were recorded on anteroposterior pelvis radiographs. Results: The mean stem anteversion was 17.5° (standard deviation = 10.8°) from the TEA and 21.7° (standard deviation = 11.3°) from the PCA. Ten of 30 cups were appropriately anteverted; however, all the cups had appropriate abduction. Combined version when using the TEA resulted in 79% (23/29) of patients within the “safe zone” of 25°-50°. Pearson correlation coefficients were high for both stem anteversion from the TEA (R = 0.96) and PCA (R = 0.98); however, interobserver reliability for combined component anteversion was greater for the TEA (kappa, 0.83 vs 0.65). Conclusions: Combined anteversion within the “safe zone” was achieved 79% of the time with DA-THA. Interestingly, most of the “excessive” combined anteversion appears to be related to increased anteversion of the acetabular component with only 10 patients within the acetabular cup “safe zone” of 5°-25°.

Background:. Dual-plate constructs have become an increasingly common fixation technique for midshaft clavicle fractures and typically involve the use of mini-fragment plates. The goal of this technique is to reduce plate prominence and implant irritation. However, limited biomechanical data exist for these lower-profile constructs. The study aim was to compare dual mini-fragment orthogonal plating with small-fragment clavicle plates for biomechanical noninferiority and to determine if an optimal plate configuration could be identified using a cadaveric model. Methods:. Twenty-four cadaveric clavicles were randomized to 1 of 6 groups, stratified by computed tomography-based bone mineral content (BMC): precontoured superior or anterior fixation using a single 3.5-mm Locking Compression Plate (LCP), and 4 different dual-plating constructs utilizing 2.4-mm and 2.7-mm Adaptation plates or LCPs. An inferior butterfly fracture was created. Axial, torsional, and bending (anterior and superior surface loading) stiffnesses were determined through nondestructive cyclic testing, followed by a load-to-failure test in 3-point superior surface bending. Results:. For axial stiffness, the 2 dual-plate constructs with a superior 2.4-mm and anterior 2.7-mm plate (either Adaptation or LCP) were significantly stiffer than the other 4 constructs (p = 0.021 and p = 0.034). For both superior and anterior bending, the superior 2.4-mm and anterior 2.7-mm plate constructs were significantly stiffer when compared with the 3.5-mm superior plate (p = 0.043). No significant differences were found in torsional stiffness or load to failure between the different constructs. Conclusions:. Dual plating using mini-fragment plates is biomechanically superior for the fixation of midshaft clavicle fractures when compared with a single, superior, 3.5-mm plate and has biomechanical properties similar to those of a 3.5-mm plate placed anteriorly. With the exception of axial stiffness, no significant differences were found when different dual-plating constructs were compared with each other. Clinical Relevance:. This study validates the use of dual plating for midshaft clavicle fractures.

The use of cruciate substituting (CS) total knee replacement has been increasing in popularity. There are numerous factors that have likely contributed to this expansion. The CS philosophy incorporates the ease of use commonly cited by advocates of the posterior stabilized (PS) total knee design with the bone preservation associated with a cruciate retaining (CR) design. The ultra-congruent highly cross-linked polyethylene liner increases stability without an appreciable change in wear. Furthermore, balancing the flexion and extension gaps does not require “titrating” the posterior cruciate ligament, improving the user-friendliness. This paper reviews the nuances of this implant design compared to PS and CR designs as well as provides surgical technique recommendations/considerations.

Cancers and neurological disorders are two major types of diseases. We previously developed a new concept termed “Aberrant Cell Cycle Diseases” (ACCD), revealing that these two diseases share a common mechanism of aberrant cell cycle re-entry. The aberrant cell cycle re-entry is manifested as kinase/oncogene activation and tumor suppressor inactivation, which are hallmarks of both tumor growth in cancers and neuronal death in neurological disorders. Therefore, some cancer therapies (e.g., kinase inhibition, tumor suppressor elevation) can be leveraged for neurological treatments. The United States Food and Drug Administration (US FDA) has so far approved 74 kinase inhibitors, with numerous other kinase inhibitors in clinical trials, mostly for the treatment of cancers. In contrast, there are dire unmet needs of FDA-approved drugs for neurological treatments, such as Alzheimer’s disease (AD), intracerebral hemorrhage (ICH), ischemic stroke (IS), traumatic brain injury (TBI), and others. In this review, we list these 74 FDA-approved kinase-targeted drugs and identify those that have been reported in preclinical and/or clinical trials for neurological disorders, with a purpose of discussing the feasibility and applicability of leveraging these cancer drugs (FDA-approved kinase inhibitors) for neurological treatments.

High-energy anterior cruciate ligament (high-energy ACL) injury, occurring in high-energy rotatory trauma of the knee, can accompany a unique fracture pattern that involves depression of the slope of the posterolateral tibial plateau (PLTP). These injuries are challenging to manage due to the lack of a gold-standard arthroscopic procedure that addresses both ACL deficiency and depressed PLTP slope. In such injuries, a one-stage approach may be used to (1) reconstruct the ACL or (2) reduce and fix the avulsed tibial spine, while concomitantly performing an arthroscopy-assisted reduction of a PLTP fracture that restores the anatomic slope of the tibial plateau. To summarize, using combined arthroscopic and fluoroscopic visualization, a tibial tunnel reaching 1 cm distal to the depressed plateau fragment is created using a cannulated drill. The drill is used to punch up the depressed fragment to its anatomic location, restoring the original slope of the PLTP. The corrected slope is then fixed in situ using a press-fit fibular allograft to stabilize the corrected PLTP slope. Use of this minimally invasive arthroscopic technique to restore the PLTP slope may help prevent graft failure of the reconstructed ACL and improve patient outcomes.

Introduction: Traumatic brain injury (TBI) is frequently encountered in geriatric patients, but there is a paucity of data describing TBI in the elderly. Here, we show the age of patients with TBI is increasing at our medical center and discuss the relationship between age and injury severity with patient outcomes.Methods: This is a retrospective analysis of 3,179 adult patients with TBI treated at the University of California, Davis Level 1 Trauma Center between 2009 and 2016. Age, Glasgow Coma Scale (GCS), and CT Rotterdam Scores were recorded. Age was analyzed as both a continuous and categorical variable (18–34, 35–50, 51–65, >65 years-old). Extended Glasgow Outcome Scale was obtained at 3 and 6 months and dichotomized into favorable and unfavorable outcomes. Multivariable general linear regression models, chi-square, logistic regression analyses and ANOVA were used for statistical analyses; a p < 0.05 was considered significant.Results: The mean age of patients was 52.2 ± 21.9 years with a male predominance (69%). There was a significant trend (p = 0.002) toward an increase in mean age each year, increasing by 4.4 years (p = 0.008) over the course of the analysis. Older patients had a higher mean GCS compared to younger patients with the same CT Rotterdam Score (p = 0.027), this becoming more pronounced with worse CT Rotterdam Scores. The >65 group had a 4-fold increased risk for unfavorable outcome when compared to the 18–34 group, this effect being most pronounced after mild TBI.Conclusions: The mean age of TBI patients is increasing at our trauma center. The largest disparity in outcomes across age was seen in patients with a mild GCS and low CT Rotterdam Scores, suggesting that these markers of injury severity may underestimate the severity of injury in the elderly population. This information highlights the need for clinical trials and validation of outcome markers in geriatric TBI.

The following surgical technique describes a case of a 51-year-old man with severe juvenile rheumatoid arthritis that required a 2-stage revision of an infected revision total knee implant. The patient had previously been implanted with a revision rotating platform, constrained condylar device which gained excellent fixation through the use of diaphyseal-engaging stems, and a well-ingrown, fully porous-coated femoral metaphyseal sleeve. To avoid intraoperative complications while removing the femoral sleeve, a novel technique for femoral sleeve extraction was used. Using this technique, the femoral sleeve was successfully removed without intraoperative fracture or substantial bone loss.

Introduction: Adverse reactions to metal debris with catastrophic failures have been seen with a number of metal on metal (MoM) total hip designs. Understanding survivorship and factors associated with failure will allow for more targeted surveillance of those patients at highest risk for failure. The purpose of this study was to assess the mid to long term survivorship and specific factors associated with failure for a large cohort of a single modular MoM design. Methods: Consecutive patients treated with a modular metal on metal bearing with a five to fourteen year follow-up were included. Clinical outcome scores and radiographic data were prospectively collected. Failure was defined as revision of either component for any reason during the study period. Multiple implant, surgical, and patient factors were analyzed for associations with elevated ion levels or revision due to adverse reactions to metal debris. Results: The average age at the time of surgery for the 253 patients included in the study was 55. There were 28 revisions (7.5%), eight due to metallosis (2%). Survivorship was 89% at 12.6 years with revision for any reason as the end point. Survivorship was 93% when limited to revision for ALTR as the end point. Time in situ was the only variable that was statistically associated with an increased risk of failure due to ALTR (p

Aims: In the setting of rising healthcare costs, more cost efficiency in total hip arthroplasty (THA) is required. Following THA, most patients are monitored with serial hemoglobin testing despite few needing blood transfusions. This testing adds cost and may not be necessary in most patients. This study aims to identify factors associated with transfusion, therefore guiding hemoglobin monitoring following THA. Patients and Methods: Patients who underwent primary THA in 2015 were identified using the National Surgical Quality Improvement Project (NSQIP) database. Patient discharged on the day of surgery were excluded. Patients were classified into those receiving transfusion versus no transfusion. Demographics and comorbidities were compared between groups followed by univariate and multivariate analysis, allowing identification of patient characteristics and comorbidities associated with transfusion. Results: Overall, 28664 patients who underwent THA patients were identified. Within this group, 6.1% (n=1737) had a post-operative transfusion. Patients receiving a blood transfusion were older, had lower body mass index, and had higher rates of chronic obstructive pulmonary disease (COPD), heart failure, dialysis, prior transfusion, and were more frequently ASA class 3-4 (p70, diabetes, smoking, COPD, prior transfusion, and operative time >2 hours as independent risk factors for transfusion. Conclusion: Among THA patients, characteristics and comorbidities exist that are associated with increased likelihood of transfusion. Presence of these factors should guide hemoglobin monitoring post-operatively. Selective hemoglobin monitoring can potentially decrease the cost of THA.

Introduction: Metal on Metal (MoM) total hip arthroplasty (THA) has been largely abandoned in the United States secondary to high failure rates. Many of the failures are attributed to adverse local tissue reactions (ALTR). Therefore, patients that have a MoM THA are routinely screened by checking serum metal ion levels every two years, as was recommended by the FDA. However, there is limited data on the costs of current screening protocols. Materials and Methods: 318 consecutive patients who underwent a MoM THA at a single institution were retrospectively enrolled. The average follow-up was 8.2 years. Clinical data, metal ion levels, revision and reoperation rates were prospectively collected. The costs of clinical screening for this patient population was calculated and compared to the cost of an annual screening protocol. Results: 12 patients had either an elevated Co or Cr level (>4.5 ppb). Eight patients were revised secondary to ALTR. The total cost of screening during the study was $612,250. Additionally, if annual screening had been performed, total screening costs would be approximately $1,719,200. Discussion: Eight patients in the following study were revised secondary to ALTR with a total cost of screening of $612,500. These costs are substantially less than the cost of annual screening ($1,719,200). Due to the considerable costs of screening asymptomatic MoM THA patients, we recommend both optimizing the frequency of screening and evaluating the specific risk of the implant being screened.

Introduction: There has been recent enthusiasm for the use of modular stemmed tibial components in obese (BMI ≥35kg/m2) patients undergoing primary total knee arthroplasty (TKA). This has been mainly driven by studies demonstrating statistically significant increases in the rates of aseptic tibial loosening (ATL) in this patient population. However, to our knowledge, no study has specifically evaluated the cost effectiveness of this current recommendation. Methods: The following study was performed utilizing previously obtained data on the incidence of ATL in obese patients undergoing primary TKA. This data was then utilized to create a cost calculator that can evaluate the price point at which the use of a stemmed tibial component in all obese patients would be less than or equal to the costs of revision surgery if a stemmed implant was not utilized. Results: Utilizing historical data with a revision rate of 4% for aseptic loosening of the tibia on obese patients, a cost calculator was developed. The cost calculator requires the input of expected or known incidence of ATL utilizing a stem extension and the expected or known costs of revision for ATL. Conclusion: The following cost calculator quickly determines a price point at which the use of a tibial stem offsets the costs of revision surgery. While this study may not provide an exact cost-effectiveness of modular stem fixation due to model limitations, it will hopefully initiate the discussion for providing more cost-effective individualized care for this patient population.

We describe a unique, utilitarian reconstructive treatment option known as tibial “spackling” for chronic, localized medial joint line pain corresponding with progressive radiographic peripheral medial tibial bone loss beneath a well-fixed revision total knee arthroplasty tibial baseplate. It is believed that this localized pain is due to chronic irritation of the medial capsule and collateral ligament from the prominent medial edge of the tibial component. In the setting of failed nonoperative treatment, our experience with utilizing bone cement to reconstruct the medial tibial bone defect and create a smooth medial tibial surface has been successful in eliminating chronic medial soft tissue irritation.

A 44-year-old female presented with a chief complaint of left knee pain and dysfunction. The patient had a complex surgical history including patellar fracture repair, subsequent patellar ligament repair, and ultimately allograft reconstruction which was complicated by septic arthritis requiring graft resection. On presentation to our clinic, she was noted to have significant degenerative disease in addition to chronic extensor mechanism deficiency. She underwent primary total knee arthroplasty with concomitant tibial tubercle osteotomy and advancement. The patient has had an excellent result postoperatively including return of full range of motion without residual extensor lag.

Running is a popular form of exercise, although runners are prone to injury from repeated impact. Running shoes can limit impact forces, but they deteriorate with use. Mechanical ageing typically involves repeatedly compressing the midsole while measuring the energy absorbed within compression cycles to assess degradation. Literature suggests mechanical aging often causes a higher rate of degradation than natural ageing. This work investigated the effect of introducing rest periods into mechanical ageing. Five shoes were mechanically aged using a sine plus dwell waveform (1.25 Hz, max. load 1.5 kN) for seven hours, equating to a simulated distance of 60 km. Three of the shoes were rested for 22 hours every 20 km. The shoes aged with rest periods absorbed more energy than their unrested counterparts for the first 10 km when testing recommenced. This finding has implications for the mechanical ageing, design and recommended lifespan of running shoes.

Undergraduate study behaviours, principally lecture attendance and additional study, are shown to predict better student achievement by many researchers. Despite this, there is not much evidence on the determinants of these behaviours. This is the first paper to explore the determinants of study behaviours across multiple subject areas; and is the first to incorporate students' noncognitive traits into such a model; that the authors are aware of. This enables the formation of policy that can improve academic achievement by encouraging study behaviour. The results show that students' noncognitive traits, in particular conscientiousness and future-orientation, are important determinants of lecture attendance and additional study hours. In fact, there is very little that explains undergraduate study behaviour besides noncognitive traits. Standard economic factors, such as family income, financial aid and parental transfers, are not predictive of study behaviours. Some comments are provided on a potential behavioural economics approach to encouraging study behaviours. (Contains 2 tables and 2 figures.)

During a routine post-operative orthopaedic radiograph reading session, repeated unusual radiographic soft tissue and bone appearances became evident. It was discovered that these patients had received biodegradable magnesium implants which have recently been introduced into orthopaedic clinical practice. To the untrained eye, the combination of peri-metallic bone resorption with associated soft tissue gas, could easily be mistaken for post-operative infection. The aim of this study is to properly characterise the radiographic post-operative appearances of biodegradable magnesium orthopaedic hardware. We retrospectively evaluated radiographs of all patients who underwent magnesium screw implantation for fractures over a 6 month period. Four patients, mean age of 9.75 (range: 6-15) years who underwent magnesium screw fixation following fracture were included in the study. Follow up duration was 100 days (range: 75-122) with a mean of 2.5 postoperative radiographs being performed per patient during this period. All cases demonstrated post-operative peri-metallic radiolucency which developed around the magnesium screws on x-ray, which subsequently resorbed over time. Peri-metallic soft tissue gas was observed in all patients. In two cases, magnesium implants fractured. As the use of biodegradable metal implants becomes more common, it is important for radiologists to be aware of their imaging characteristics. Prior to reporting a case, it would be prudent to know if biodegradable screws have been utilised and whether there exists a clinical concern for post-operative infection in patients with these particular implants, in which case it would be critical not to dismiss peri-prosthetic radiolucencies and soft tissue gas as merely a sequela of the natural metal degradation process. [ABSTRACT FROM AUTHOR]

In the setting of periprosthetic joint infection, the complete removal of implants and cement can be challenging with well-fixed, cemented implants about the knee. This can get especially complex in the setting of long cemented femoral component stems. Osteotomies are well described in the proximal femur and tibia for removal of implants and cement. There is little information available on distal femoral osteotomies. We describe an anterolateral oblique distal femoral osteotomy for the removal of well-fixed, cemented components in resection knee arthroplasty that preserves vascularity to the osteotomized segment.