Retinal vascular occlusions in COVID-19 infection and vaccination: a literature review.

PURPOSE: Abnormal hypercoagulability and increased thromboembolic risk are common in patients with coronavirus disease (COVID-19). COVID-19 has been suggested to cause retinal vascular damage, with several studies on COVID-19 patients with retinal vascular occlusions. We reviewed and investigated studies on retinal vascular occlusions in patients diagnosed with COVID-19 and in those vaccinated for COVID-19. METHODS: Studies that reported retinal vascular occlusion in COVID-19 patients or in vaccinated people were identified using the terms "retinal occlusion," together with "severe acute respiratory syndrome coronavirus 2", "SARS-CoV-2," "COVID-19," "coronavirus," and "vaccine," through systematic searches of PubMed and Google Scholar databases until January 7, 2022. RESULTS: Thirteen cases of retinal artery occlusion (RAO) and 14 cases of retinal vein occlusion (RVO) were identified among patients diagnosed with COVID-19. Half of the patients with RAO or RVO revealed no systemic disorders except current or past COVID-19, and ocular symptoms were the initial presentation in five cases. Among patients with RAO, most presented with central RAO at 1-14 days of COVID-19 diagnosis, with abnormal coagulation and inflammatory markers. Among those with RVO, two-thirds presented with central RVO and one-third with RVO. Eleven cases with acute macular neuroretinopathy (AMN) and/or paracentral acute middle maculopathy (PAMM) were reported among patients with COVID-19, presenting scotoma resolved spontaneously in most cases. Among the 26 cases vaccinated with either mRNA or adenoviral vector vaccines for COVID-19 and presenting retinal vascular occlusions, there were more RVO cases than RAO cases, and ocular symptoms mostly occurred within 3 weeks after vaccination. One case presented bilateral AMN and PAMM after COVID-19 vaccination. CONCLUSION: Retinal vascular occlusions might be a manifestation of COVID-19, although rare, especially in patients at risk of systemic hypercoagulability and thromboembolism. For COVID-19 vaccines, the causal relationship is controversial because there are few case reports of retinal vascular occlusions after COVID-19 vaccination.

Upconverting nanoparticle-containing erythrocyte-sized hemoglobin microgels that generate heat, oxygen and reactive oxygen species for suppressing hypoxic tumors.

Inspired by erythrocytes that contain oxygen-carrying hemoglobin (Hb) and that exhibit photo-driven activity, we introduce homogenous-sized erythrocyte-like Hb microgel (µGel) systems (5-6 µm) that can (i) emit heat, (ii) supply oxygen, and (iii) generate reactive oxygen species (ROS; 1O2) in response to near-infrared (NIR) laser irradiation. Hb µGels consist of Hb, bovine serum albumin (BSA), chlorin e6 (Ce6) and erbium@lutetium upconverting nanoparticles (UCNPs; ∼35 nm) that effectively convert 808 nm NIR light to 660 nm visible light. These Hb µGels are capable of releasing oxygen to help generate sufficient reactive oxygen species (1O2) from UCNPs/Ce6 under severely hypoxic condition upon NIR stimulation for efficient photodynamic activity. Moreover, the Hb µGels emit heat and increase surface temperature due to NIR light absorption by heme (iron protoporphyrin IX) and display photothermal activity. By changing the Hb/UCNP/Ce6 ratio and controlling the amount of NIR laser irradiation, it is possible to formulate bespoke Hb µGels with either photothermal or photodynamic activity or both in the context of combined therapeutic effect. These Hb µGels effectively suppress highly hypoxic 4T1 cell spheroid growth and xenograft mice tumors in vivo.

Outcome of multi-staged induced membrane technique based on post-debridement cultures for the management of critical-sized bone defect following fracture-related infection.

The authors' institution utilizes multi-staged induced membrane technique protocol based on post-debridement culture in treating patients with critical-sized bone defect in lower extremity due to infected nonunion or post-traumatic osteomyelitis. This study aimed to evaluate the success rate of this limb reconstruction method and which risk factors are associated with recurrence of infection. 140 patients were treated with multi-staged induced membrane technique from 2013 to 2018 and followed up more than 24 months after bone grafting. The primary success rate of limb reconstruction was 75% with a mean follow-up of 45.3 months. The mean Lower Extremity Functional Scale in success group improved from 12.1 ± 8.5 to 56.6 ± 9.9 after the treatment. There were 35 cases of recurrence of infection at a mean of 18.5 months after bone grafting. Independent risk factors for recurrence of infection were infected free flap, surprise positive culture, deviation from our surgical protocol, and elevated ESR before final bone graft procedure. In conclusion, this study showed that multi-staged induced membrane technique protocol based on post-debridement culture resulted in 75% success rate and revealed a number of risk factors for recurrence of infection.

The difference in the corridor of the antegrade posterior column screw according to the presence of pelvic dysmorphism.

INTRODUCTION: Antegrade posterior column screw (aPCS) fixation via the anterior approach has been widely used for separated the posterior columns in acetabular fracture treatment. Although the relationship between pelvic dysmorphism and sacroiliac screws has been widely studied, no studies have reported on the clinical impact of pelvic dysmorphism on acetabular fractures. This study aimed to reveal the difference in the insertion angle and entry point of aPCS between the dysmorphic and normal pelvises. METHODS: Patients diagnosed with unilateral acetabular fractures and who underwent pelvic computed tomography scans between 2013 and 2019 in two institutes were enrolled in this study. Patients were divided into the dysmorphic and control groups according to the sacral dysmorphic score, which predicts the presence of pelvic dysmorphism, and each group enrolled 130 patients. The semitransparent 3D hemipelvis model was reconstructed using a 3D reconstruction program. The sagittal and coronal angles of a virtual cylinder that fill the safe corridor of the column screw the most were measured. The surface area of the safe corridor and distance of the optimal entry point from the anterior border of the sacroiliac joint were analyzed. The measurements were compared between the dysmorphic and control groups. RESULTS: The average sacral dysmorphic score in the normal and dysmorphic pelvis groups was 56.1 and 81.0, respectively. There were no significant differences in demographic data, including age, sex, height, weight, and body mass index, between the dysmorphic and control groups. There was a significant difference in the average sagittal insertion angle of PCs, which was 38.3° in the control group and 27.2° in the dysmorphic group (P < 0.001). The coronal insertion angles were not significantly different. The dysmorphic group presented longer straight distances (25.9 vs 24.8 mm, P = 0.026) and had a smaller aPCS surface area (685 vs 757 mm2, P < 0.001) than the control group. CONCLUSION: The present study describes a difference in the corridor of aPCS between the dysmorphic and normal pelvis. Insertion of aPCS in the dysmorphic pelvis requires a more acute angular trajectory in the sagittal plane than that in the normal pelvis.

Combined Antitumor Therapy Using In Situ Injectable Hydrogels Formulated with Albumin Nanoparticles Containing Indocyanine Green, Chlorin e6, and Perfluorocarbon in Hypoxic Tumors.

Combined therapy using photothermal and photodynamic treatments together with chemotherapeutic agents is considered one of the most synergistic treatment protocols to ablate hypoxic tumors. Herein, we sought to fabricate an in situ-injectable PEG hydrogel system having such multifunctional effects. This PEG hydrogel was prepared with (i) nabTM-technique-based paclitaxel (PTX)-bound albumin nanoparticles with chlorin-e6 (Ce6)-conjugated bovine serum albumin (BSA-Ce6) and indocyanine green (ICG), named ICG/PTX/BSA-Ce6-NPs (~175 nm), and (ii) an albumin-stabilized perfluorocarbon (PFC) nano-emulsion (BSA-PFC-NEs; ~320 nm). This multifunctional PEG hydrogel induced moderate and severe hyperthermia (41-42 °C and >48 °C, respectively) at the target site under two different 808 nm laser irradiation protocols, and also induced efficient singlet oxygen (1O2) generation under 660 nm laser irradiation supplemented by oxygen produced by ultrasound-triggered PFC. Due to such multifunctionality, our PEG hydrogel formula displayed significantly enhanced killing of three-dimensional 4T1 cell spheroids and also suppressed the growth of xenografted 4T1 cell tumors in mice (tumor volume: 47.7 ± 11.6 and 63.4 ± 13.0 mm3 for photothermal and photodynamic treatment, respectively, vs. PBS group (805.9 ± 138.5 mm3), presumably based on sufficient generation of moderate heat as well as 1O2/O2 even under hypoxic conditions. Our PEG hydrogel formula also showed excellent hyperthermal efficacy (>50 °C), ablating the 4T1 tumors when the irradiation duration was extended and output intensity was increased. We expect that our multifunctional PEG hydrogel formula will become a prototype for ablation of otherwise poorly responsive hypoxic tumors.

Effect of Recombinant Human Bone Morphogenetic Protein-2 (rhBMP-2) with Hydroxyapatite Carrier in Induced Membrane Technique: A Retrospective Propensity Score-Matched Study.

OBJECTIVES: To determine the effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) with hydroxyapatite (HA) carrier augmentation in managing critical-sized bone defect (CSBD) with induced membrane technique (IMT). DESIGN: Retrospective comparative study. SETTING: Academic level I trauma center. PATIENTS/PARTICIPANTS: The study included 14 patients who underwent rhBMP-2 with HA carrier (rhBMP-2/HA) augmentation in IMT for managing CSBD (BMP group). Moreover, 14 patients who underwent IMT without rhBMP-2 augmentation were matched by propensity score analysis (non-BMP group). INTERVENTION: IMT with or without rhBMP-2/HA augmentation. MAIN OUTCOME MEASUREMENT: Changes in quality and quantity measurements of grafted bone to regenerated bone using serial computed tomography. RESULTS: In the BMP and non-BMP groups, the changes in densities from grafted bone to regenerated bone were +379.63 Hounsfield unit and +248.55 Hounsfield unit (P = 0.034), changes in dense bone percentage were +37.52% and +23.31% (P = 0.027), corticalization rates under the plate were 79.70% and 39.30% (P = 0.007), changes in volume were -20.77% and -23.35% (P = 0.812), union rates were 85.71% and 78.57% (P = 0.622), numbers of patients requiring additional procedures were 4 and 3 (P = 0.663), and time to union were 316.3 and 585.45 days (P = 0.040), respectively. CONCLUSIONS: RhBMP-2/HA augmentation increases the density of regenerated bone, enhances corticalization under the plate, and shortens the time to union while managing CSBD with IMT. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Photoreactive-proton-generating hyaluronidase/albumin nanoparticles-loaded PEG-hydrogel enhances antitumor efficacy and disruption of the hyaluronic acid extracellular matrix in AsPC-1 tumors.

Depletion of tumor extracellular matrix (ECM) is viewed as a promising approach to enhance the antitumor efficacy of chemotherapeutic-loaded nanoparticles. Hyaluronidase (HAase) destroys hyaluronic acid-based tumor ECM, but it is active solely at acidic pHs of around 5.0 and is much less active at physiological pH. Herein, we report the development of our novel UV-light-reactive proton-generating and hyaluronidase-loaded albumin nanoparticles (o-NBA/HAase-HSA-NPs). The method to prepare the nanoparticles was based on pH-jump chemistry using o-nitrobenzaldehyde (o-NBA) in an attempt to address the clinical limitation of HAase. When in suspension/PEG-hydrogel and irradiated with UV light, the prepared o-NBA/HAase-HSA-NPs clearly reduced the pH of the surrounding medium to as low as 5.0 by producing protons and were better able to break down HA-based tumor cell spheroids (AsPC-1) and HA-hydrogel/microgels, presumably due to the enhanced HA activity at a more optimal pH. Moreover, when formulated as an intratumor-injectable PEG hydrogel, the o-NBA/HAase-HSA-NPs displayed significantly enhanced tumor suppression when combined with intravenous paclitaxel-loaded HSA-NPs (PTX-HSA-NPs) in AsPC-1 tumor-bearing mice: The tumor volume in mice administered UV-activated o-NBA/HAase-HSA-NPs and PTX-HSA-NPs was 198.2 â€‹± â€‹30.0 â€‹mm3, whereas those administered PBS or non-UV-activated o-NBA/HAase-HSA-NPs and PTX-HSA-NPs had tumor volumes of 1230.2 â€‹± â€‹256.2 and 295.4 â€‹± â€‹17.1 â€‹mm3, respectively. These results clearly demonstrated that when administered with paclitaxel NPs, our photoreactive o-NBA/HAase-HSA-NPs were able to reduce pH and degrade HA-based ECM, and thereby significantly suppress tumor growth. Consequently, we propose our o-NBA/HAase-HSA-NPs may be a prototype for development of future nanoparticle-based HA-ECM-depleting tumor-ablating agents.

Multifragmentary patellar fracture has a distinct fracture pattern which makes coronal split, inferior pole, or satellite fragments.

The present study aimed to map the location and frequency of fracture lines on the coronal articular and sagittal planes in multifragmentary patellar fractures. 66 multifragmentary patellar fractures were digitally reconstructed using the 3D CT mapping technique. The coronal articular surface and midsagittal fracture maps were produced by superimposing each case over a single template. Each fracture line was classified based on the initial displacement and orientation. We evaluated the frequency and direction of the fracture line, coronal split fragment area, and satellite and inferior pole fragment presence. Coronal articular surface fracture mapping identified primary horizontal fracture lines between the middle and inferior one-third of the articular surface in 63 patients (95.4%). Secondary horizontal fracture lines running on the inferior border of the articular facet were confirmed (83.3%). Secondary vertical fracture lines creating satellite fragments were mostly located on the periphery of the bilateral facet. Midsagittal fracture mapping of primary and secondary horizontal fracture lines with the main coronal fracture line revealed a predominantly X-shaped fracture map. The consequent coronal split fragment and inferior pole fracture were combined in most cases. In conclusion, the multifragmentary patellar fracture has a distinct pattern which makes coronal split, inferior pole, or satellite fragments.

Proximal tibia with an inserted nail can be an available donor site for harvesting cancellous bone.

INTRODUCTION: A pre-existing implant at the harvesting site might dissuade the surgeon from considering the site as available for bone harvesting. This study aimed to investigate the quantity of cancellous bone graft that can be harvested from a proximal tibia with an inserted nail and to report the clinical outcomes of this bone graft harvesting technique. HYPOTHESIS: Our hypothesis was that a certain amount of cancellous bone graft could be harvested from a proximal tibia with an inserted nail without compromising the surrounding environment and outcome of nonunion treatment. MATERIAL AND METHODS: Bone grafting from an ipsilateral proximal tibia with an inserted nail was performed in 32 patients for treating defect nonunion. The amount of harvested bone was measured using three parameters (weight, height, and volume). The effects of the proximal locking screw position on the quantity and location of bone graft harvest were analyzed. Clinical outcomes were evaluated by assessing the radiologic healing of the bone graft site and by assessing the donor site complications. RESULTS: The mean bone defect volume in the nonunion site was 31.1±18.3 (range, 10.6-87.0) cm3. The mean quantity of harvested bone from proximal tibias with an inserted nail was 21.2g, height was 3.9cm, and volume was 26.3 cm3. A positive correlation was found between the quantity of harvested bone and the level of the lateral oblique interlocking screw hole in the tibial nail. All grafted bone successfully consolidated in all cases at an average of 5.8 months postoperatively. However, joint penetration during bone harvesting occurred in one case. DISCUSSION: The bony defect, which measured about 14.3 cm3 could be filled with cancellous bone from a PT with an existing IM nail, without additional bone graft requirements. Even if an intramedullary nail exists inside the proximal tibia, harvesting cancellous bone at this site can be a viable option without serious complications. LEVEL OF EVIDENCE: IV; Retrospective descriptive study.

More weighted cancellous bone can be harvested from the proximal tibia with less donor site pain than anterior iliac crest corticocancellous bone harvesting: retrospective review.

BACKGROUND: Iliac crest is the most preferred autogenous bone graft harvesting donor site while it has sorts of complications like prolonged pain, hematoma, and fracture. Harvesting cancellous bone from proximal tibia is also increasingly being used because of lower complications and less donor site pain. However, there are lack of studies to compare these two donor sites in detail. Thus, we proposed to investigate the available amount of autogenous bone graft from the proximal tibia. METHODS: Fifty-one patients who underwent simultaneous bone graft harvest from the PT and the AIC to fill up the given critical sized bone defects were enrolled in this study. We prospectively collected data including the weight of the harvested bone, donor site pain using the visual analog scale (VAS) score, and complications between the two sites. RESULTS: The mean weight of cancellous bone harvested from the PT was greater than AIC (33.2g vs. 27.4g, p = 0.001). The mean VAS score was significantly lesser in the PT up to 60 days after harvesting (p < 0.001). There was persistent pain up to 90 days in four PT patients and in seven AIC patients. The major complication was reported only in AIC patients (11.8%). CONCLUSIONS: Harvesting cancellous bone from the PT is an acceptable alternative to the AIC for autogenous bone grafting owing to availability of more weighted graft bone and less donor site pain.

Usefulness of the obturator hook technique for guiding the initial trajectory control in infra-acetabular screw placement.

PURPOSE: Proper placement of infra-acetabular screws is technically demanding; there is a limited safe zone for screw fixation because of the complexity of the bone anatomy around the hip joint and the vulnerability of the major neurovascular bundles in the pelvic cavity. We aimed to present the obturator hook technique as a surgical technique for infra-acetabular screw placement in acetabular and pelvic fractures and report its radiological outcomes. METHODS: Patients treated with infra-acetabular screw placement using the obturator hook technique between January 2015 and August 2020 were enrolled in this study. We collected data on demographics, surgical approach, reduction status, complications, and outcomes. The radiological outcomes of infra-acetabular screw placement based on computed tomography findings were evaluated as follows: success, articular penetration, or out of the bone. RESULTS: Thirty-five patients underwent infra-acetabular screw placement (26 men, 9 women; mean age, 55 years; range, 27-90 years). One patient underwent bilateral infra-acetabular screw placement; therefore, 36 infra-acetabular screws were inserted in all patients. An ideal placement was achieved with 27 infra-acetabular screws (27/36, 75%). Seven infra-acetabular screws (7/36, 19%) showed articular penetration, and two infra-acetabular screws (2/36, 6%) were placed outside the bone. One patient with articular penetration and mechanical symptoms of the hip joint required screw replacement. No other complications, including obturator nerve and vascular injuries, were observed. CONCLUSION: The obturator hook technique could be a favorable and individualized method for infra-acetabular screw placement in patients with acetabular and pelvic fractures. LEVEL OF EVIDENCE: IV, retrospective descriptive study.

Hyperthermal paclitaxel-bound albumin nanoparticles co-loaded with indocyanine green and hyaluronidase for treating pancreatic cancers.

Albumin nanoparticles have become an attractive cancer nanomedicine platform due to their pharmaceutical advantages. Recently, photothermal therapy has been extensively applied to cancer treatment due to heat-induced tumor ablation. Herein, we fabricated albumin nanoparticles (HSA-NPs) loaded with paclitaxel (PTX), indocyanine green (ICG; a hyperthermal agent) and hyaluronidase (HAase) that breaks down hyaluronan, a major component of the extracellular matrix (ECM) in tumors. Synthesis was based on a slightly modified nanoparticle albumin-bound (Nab™) technique. The prepared nanoparticles (PTX/ICG/HAase-HSA-NPs) had a spherical shape with an average size of ~ 110 nm and a zeta potential of ~ -30.4 mV. They displayed good colloidal stability and typical patterns of ICG, HSA and HAase in UV-VIS-NIR and circular dichroism spectroscopic analysis. PTX/ICG/HAase-HSA-NPs were found to have excellent hyperthermal effects in response to near-infrared laser irradiation (808 nm) (up to > 50 °C over 4 min). The hyperthermia conducted by PTX/ICG/HAase-HSA-NPs resulted in significant cytotoxicity to pancreatic AsPC-1 cells at both severe (> 50 °C) and mild (41-42 °C) hyperthermal states in conjunction with the inherent cytotoxic activity of paclitaxel. Furthermore, the confocal images of AsPC-1 cell spheroids proved PTX/ICG/HAase-HSA-NPs were able to permeate deeply into the three-dimensional tumor tissue mimicry structure. Most of all, PTX/ICG/HAase-HSA-NPs maintained all these physicochemical and anti-cancer properties irrespective of the amount of embedded HAase (1-5 mg). Our results demonstrated that PTX/ICG/HAase-HSA-NPs are a promising hyperthermal/chemotherapeutic anticancer agent.

Indocyanine Green and Curcumin Co-Loaded Nano-Fireball-Like Albumin Nanoparticles Based on Near-Infrared-Induced Hyperthermia for Tumor Ablation.

BACKGROUND: Indocyanine green (ICG) has received considerable interest as a biocompatible organic photothermal agent, and curcumin (Cur) is considered an attractive natural chemopreventive and chemotherapeutic compound. However, the in vivo applicability of ICG and Cur is significantly restricted by their poor ability to target tumors and their extremely low solubility. MATERIALS AND METHODS: To address these problems, ICG/Cur-loaded albumin nanoparticles (ICG-BSA-Cur-NPs) based on the nabTM (nanoparticle albumin-bound) technology were applied to neuroblastomas in vivo. RESULTS: The fabricated ICG-BSA-Cur-NPs were found to be spherical, ~150 nm in size and highly dispersible and stable in aqueous solution. Approximately 80% of the incorporated ICG and Cur were gradually released from the NPs over 48 h. All formulations of ICG-BSA-Cur-NPs (5~20 µg/mL) showed efficient hyperthermia profiles (up to 50-60°C within 5 min) in response to 808-nm NIR laser irradiation in vitro and in vivo. Notably, ICG-BSA-Cur-NPs illuminated with 808-nm laser irradiation (1.5 W/cm2) showed excellent cytotoxicity toward N2a cells in vitro and undisputable antitumor efficacy in N2a-xenografted mice in vivo, compared to other tested sample groups (tumor volumes for PBS, BSA-Cur-NPs, free ICG, and ICG-BSA-Cur-NPs groups were 1408.6 ± 551.9, 1190.6 ± 343.6, 888.6 ± 566.2, and 103.0 ± 111.3 mm3, respectively). CONCLUSION: We demonstrate that these hyperthermal chemotherapeutic ICG-BSA-Cur-NPs have potential as a future brain tumor treatment.

Gold nanocluster-loaded hybrid albumin nanoparticles with fluorescence-based optical visualization and photothermal conversion for tumor detection/ablation.

Gold nanoclusters (AuNCs) are viewed as effective hyperthermal agents for the treatment of tumors. Whereas AuNCs formed by the agglomeration of several to tens of gold atoms (<1-2 nm) possess significant fluorescence, they have a negligible hyperthermal effect, while AuNCs comprised of spherical gold nanoparticles (AuNPs > a few nanometers) have a marked hyperthermic effect but lose their inherent fluorescence and obstruct the intensity of neighboring fluorescent dyes due to Forster resonance energy transfer (FRET). To achieve both hyperthermia and fluorescence-based optical visualization, we generated hybrid albumin nanoparticles containing AuNCs (~88 nm) comprising AuNPs (~4.5 nm). We generated a series of formulated AuNCs and optimized the size, morphology, NIR absorbance (600-900 nm), hyperthermal activity, and fluorescence spectral characters of the resulting hybrid albumin nanoparticles (AuNCs/BSA-NPs) by considering the interparticle distance between the AuNPs and Cy5.5. Among these, AuNCs/BSA-NPs (formula D) had a strong hyperthermic effect and had well-preserved fluorescence intensity (from the attached Cy5.5) due to localized surface plasmon resonance (LSPR) and a reduction in FRET. These AuNCs/BSA-NPs were able to elevate the surface tumor temperature of HCT116-bearing mice to >50 °C following 808 nm laser irradiation (1.5 W/cm2, 10 min), which remarkably suppressed tumor growth (17.8 ±â€¯16.9 mm3vs. PBS and AuNCs/BSA-NPs (formula E): ~1850 and ~1250 mm3, respectively). Also, Cy5.5-modified AuNCs/BSA-NPs (formula D) showed good performance in optical fluorescence imaging of target tumors in HCT116 tumor-bearing mice. Together, our results indicate that the interparticle distance between albumin or Cy5.5 and AuNPs/AuNCs can be optimized to achieve both hyperthermia and fluorescence emission by striking a balance between LSPR and FRET effects. We believe that the AuNC/BSA-NPs formulation presented here can serve as a potential platform for both optically visualizing and treating colon cancers.

The Mediolateral Excursion of the Meniscal Bearing during Flexion and Extension of the Knee after Medial Mobile-Bearing Unicompartmental Knee Arthroplasty.

This mediolateral excursion of the bearing during knee motion is supposed to be caused by external rotation of the tibia during knee extension. However, to our knowledge, there is no published clinical evidence supporting these hypotheses. The current study aimed to evaluate the mediolateral excursion of the bearing during flexion-extension motion of the knee after medial unicompartmental knee arthroplasty (UKA). In 52 knees, varus/valgus (F-VarVal) or rotational position (F-Rot) of the femoral component and relative location of the bearing were measured with the standing anteroposterior and modified axial view, respectively. We adopted the modified axial radiographs that are simple to assess the bearing position in the flexed knee. The modified axial view showed excellent inter- and intraobserver agreements. F-Rot in the modified axial view and CT showed a high agreement in terms of validity (r = 0.98; p < 0.0001). On average, the bearing showed more medial position in extension than flexion of the knee. No correlation was found between the femoral component positions (F-VarVal and F-Rot) and mediolateral bearing excursion (p = 0.68 and 0.80, respectively). In conclusion, coronal location of bearing according to flexion-extension of the knee is not influenced by the coronal and axial alignment of the femoral component. With simple radiographic method, more medial position of the bearing according to flexion-extension of the knee. Our method could be used to assess axial rotation of the femoral component and spin-out phenomenon of the bearing following the medial UKA.

Healing of Atypical Subtrochanteric Femur Fractures After Cephalomedullary Nailing: Which Factors Predict Union?

OBJECTIVES: The purpose of this study was to determine the healing rate and time to union of atypical subtrochanteric fractures treated with cephalomedullary nailing. DESIGN: Retrospective review, descriptive, and analytic study. SETTING: Six level 1 trauma centers. PATIENTS/PARTICIPANTS: The study included 42 patients with 48 displaced, atypical, bisphosphonate-associated subtrochanteric femur fractures who underwent surgical intervention. INTERVENTION: Cephalomedullary femur nailing. MAIN OUTCOME MEASUREMENT: The main outcome measures were radiologic healing and time to union. RESULTS: The primary healing rate after cephalomedullary nailing of bisphosphonate-associated subtrochanteric femur fractures was 68.7% (33/48 patients). Mean time to union was 10.7 months. Malalignment was determined using the differences in neck-shaft angle (the difference between the normal side and the surgically repaired side) and sagittal angulation. These all proved to be significantly correlated with failure and delayed healing time. The cutoff points for neck-shaft angle, difference in neck-shaft angle, and sagittal angulation were 125.6, 4.4, and 5.5 degrees, respectively (receiver operating characteristic curve analysis). CONCLUSIONS: The healing rate of atypical subtrochanteric femur fractures treated with cephalomedullary nailing is lower than that previously reported for atypical femur fractures. The quality of fracture reduction proved to be the most important factor in bony union and time to union. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.