Complications following all-inside anterior cruciate ligament reconstruction.

PURPOSE: We conducted a comprehensive analysis of possible perioperative complications following all-inside anterior cruciate ligament reconstruction (ACLR). Additional techniques and tips are proposed to prevent and manage complications. METHODS: Complications following all-inside ACLR performed between December 2015 and December 2020 were retrospectively analysed. Altogether, 348 operations were performed and 275 patients were enrolled with a minimum 12-month follow-up period. Only semitendinosus autograft was utilised in most patients, and semitendinosus-gracilis autograft and allograft were used in five and 31 patients, respectively. Simultaneous meniscal repair, partial meniscectomy, and chondral surgery were performed in 29.5%, 21.1%, and 4.4% of patients, respectively. Complications were observed based on the patient's clinical condition, plain film, and magnetic resonance imaging. Clinical outcomes were assessed pre-operatively and at 12 months post-operatively, using the International Knee Documentation Committee form, Lysholm and Tegner activity scores, and KT1000 side-to-side difference. RESULTS: Intraoperative and post-operative complications developed in 65 patients (23.6%). The most common complication was cortical button malposition on the femoral side (19.3%). Intra-operative breakage of the retrograde drill was found in two cases (0.73%), with three cases (1.1%) of over-drilling with destruction of the outer cortex. Post-operatively, four (1.5%), 13 (4.7%), and 16 (5.8%) cases of infection, full-thickness re-rupture, and loss of extension, respectively, were recorded. Functional outcome scales showed significant post-operative improvement. CONCLUSION: Cortical button malposition was the most common but easily preventable complication. All-inside ACLR could be safe and promising after the suggested additional operative techniques and proper perioperative management which decrease complication rates and improve favourable outcomes.

A Retrospective Study of Unicompartmental Knee Arthroplasty Functional Outcome and the Incidence of Medial Meniscus Posterior Root Tear in Spontaneous Osteonecrosis of the Knee.

BACKGROUND: Spontaneous osteonecrosis of the knee (SONK) can lead to severe knee osteoarthritis predominantly localized to the medial compartment. We aimed to determine whether unicompartmental knee arthroplasty was an effective treatment for primary SONK. METHODS: We analyzed the functional outcomes in 23 patients with SONK (with a magnetic resonance imaging- (MRI-) confirmed diagnosis) who underwent UKA at a single center. The mean follow-up time was 67 months post-UKA. RESULTS: Significant improvements in function were indicated by reduced Oxford Knee and Visual Analogue Scale scores after UKA, and there were no specific complications after the procedures. The incidence of MRI-identified medial meniscus posterior root tear (MMPRT) was 69.6% (16/23). CONCLUSION: Unicompartmental arthroplasty for SONK is less destructive to the native knee structure than total knee arthroplasty but can achieve comparable prognosis with strict patient selection. While the precise etiology of SONK is unknown, one theory posits that a MMPRT may change the biomechanical circumstances of the knee joint, leading to osteonecrosis. Although not confirmatory, the high prevalence rate suggests that MMPRT may have a key role in the development of SONK. UKA is an effective treatment option for SONK, resulting in significant functional improvement. Long-term (>10 years) outcomes should be investigated.

Migratory flight on the Pacific Flyway: strategies and tendencies of wind drift compensation.

Applications of remote sensing data to monitor bird migration usher a new understanding of magnitude and extent of movements across entire flyways. Millions of birds move through the western USA, yet this region is understudied as a migratory corridor. Characterizing movements in the Pacific Flyway offers a unique opportunity to study complementary patterns to those recently highlighted in the Atlantic and Central Flyways. We use weather surveillance radar data from spring and autumn (1995-2018) to examine migrants' behaviours in relation to winds in the Pacific Flyway. Overall, spring migrants tended to drift on winds, but less so at northern latitudes and farther inland from the Pacific coastline. Relationships between winds and autumn flight behaviours were less striking, with no latitudinal or coastal dependencies. Differences in the preferred direction of movement (PDM) and wind direction predicted drift patterns during spring and autumn, with increased drift when wind direction and PDM differences were high. We also observed greater total flight activity through the Pacific Flyway during the spring when compared with the autumn. Such complex relationships among birds' flight strategies, winds and seasonality highlight the variation within a migration system. Characterizations at these scales complement our understanding of strategies to clarify aerial animal movements.

Bilinear Convolutional Neural Networks for Fine-grained Visual Recognition.

We present a simple and effective architecture for fine-grained recognition called Bilinear Convolutional Neural Networks (B-CNNs). These networks represent an image as a pooled outer product of features derived from two CNNs and capture localized feature interactions in a translationally invariant manner. B-CNNs are related to orderless texture representations built on deep features but can be trained in an end-to-end manner. Our most accurate model obtains 84.1%, 79.4%, 84.5% and 91.3% per-image accuracy on the Caltech-UCSD birds [66], NABirds [63], FGVC aircraft [42], and Stanford cars [33] dataset respectively and runs at 30 frames-per-second on a NVIDIA Titan X GPU. We then present a systematic analysis of these networks and show that (1) the bilinear features are highly redundant and can be reduced by an order of magnitude in size without significant loss in accuracy, (2) are also effective for other image classification tasks such as texture and scene recognition, and (3) can be trained from scratch on the ImageNet dataset offering consistent improvements over the baseline architecture. Finally, we present visualizations of these models on various datasets using top activations of neural units and gradient-based inversion techniques. The source code for the complete system is available at http://vis-www.cs.umass.edu/bcnn.

Corrective osteotomy with retrograde Fassier-Duval nail in an osteogenesis imperfecta patient with bilateral genu valgum: A case report.

RATIONALE: The treatment of osteogenesis imperfecta (OI) requires a multidisciplinary approach to maximize function and reduce fracture incidence. The aim of this case report was to discuss an alternative surgical approach to stabilize a corrective osteotomy using the Fassier Duval (FD) system in an OI patient. PATIENT CONCERNS: A 20-year-old OI woman presented with left thigh pain, gait disturbance, and bilateral genu valgus deformities. DIAGNOSES: Physical examination and standing radiographs revealed bilateral genu valgum with previous fixation implants in the femoral and the left tibia. INTERVENTIONS: Staged surgery was performed. A previous Ender pin was removed from the left femur, and a FD nail was inserted in a retrograde fashion. An intercondylar fracture was encountered while inserting the female rod in the distal left femur. After removal of a previous Rush pin from the right femur, several complications were also encountered during FD nailing of the right femur. The tip threads of the FD male nail could not achieve adequate anchorage in the region of the greater trochanter. To prevent male nail dropping, a horizontal stop Kirschner pin was inserted close to the distal end of the female nail. OUTCOME: Despite perioperative problems such as rod dropping and occurrence of an intercondylar fracture of the left distal femur, bilateral retrograde nailing using the FD system was successful. An accurate entry portal is important when performing retrograde rodding. In addition, reaming the portal to a larger diameter in order to accommodate the large head of the female nail can prevent intraoperative intercondylar split, especially when combined with an osteotomy at the distal femur. LESSONS: Selection of the proper surgical technique is dependent on both the surgeon's experience and the condition of the patient. Although not an optimal device, a FD nail can be used as an IM nail for corrective osteotomy at the distal femur in an adult OI patient with a small femoral IM canal.