Anay Patel

Aspirin and compression devices versus low-molecular-weight heparin and PCD for VTE prophylaxis in orthopedic oncology patients.

Deep venous thrombosis (DVT) and pulmonary embolism (PE) are possible sources of morbidity and mortality in patients with musculoskeletal neoplasms (MSN).

Femoral Component Rotation in Total Knee Arthroplasty: An MRI-Based Evaluation of our Options

Proper femoral component rotation is crucial in successful total knee arthroplasty. Rotation using anatomic landmarks has traditionally referenced the transepicondylar axis (TEA), Whitesides Line (WSL), or posterior condylar axis (PCA). TEA is thought to best approximate the flexion-axis of the knee, however WSL or PCA are common surrogates in the operating room. This study evaluated 560 knees using MRI-based planning software to assess the relationship of WSL and PCA to the TEA and determine if the relationships were influenced by pre-operative coronal deformity. Results showed the WSL-TEA relationship has more variability than PCA-TEA and that the PCA is more internally rotated in females and valgus knees. Axis options and historical assumptions about axis relationships may need to be reassessed as imaging technology advances.

Component sizing in total knee arthroplasty: patient-specific guides vs. computer-assisted navigation

Abstract Introduction: Patient-specific guides (PSG) and computer-assisted navigation (CAN) are technologies that have been developed to improve the accuracy and reproducibility of total knee arthroplasty (TKA). The purpose of this study is to compare the methodology by which a PSG system and an intraoperative navigation system (CAN) perform an anatomical registration and correctly predict femoral component size in TKA. Methods: One hundred and eleven PSG TKA were performed, 30 of which were concurrently evaluated with CAN. PSG-predicted and CAN-predicted femoral component size were compared with the actual component selection. The process by which PSG and CAN determines component sizing was evaluated. Results: The PSG system was both more accurate and more precise than the CAN navigation system in predicting femoral component size in TKA. Conclusion: In this study, the surgeon’s final component selection was more likely to be in accordance with the PSG rather than the CAN sizing algorithm. This study suggests that intraoperative surface registration may not be as accurate as preoperative three-dimensional magnetic resonance imaging reconstructions for establishing optimal femoral component sizing.

Caveat Emptor: Adverse Inflammatory Soft-Tissue Reactions in Total Hip Arthroplasty with Modular Femoral Neck Implants

Modular femoral neck (MFN) implants in total hip arthroplasty facilitate optimizing femoral offset and version while minimizing femoroacetabular impingement1, but component fracture and dissociation have been reported with titanium-alloy MFN implants2-6. Cobalt-chromium MFN components have improved strength compared with earlier designs, but the long-term consequences of wear and corrosion at the femoral neck-stem junction are unknown3,7. Inflammatory metal-hypersensitivity reactions have been most frequently reported in cobalt-chromium metal-on-metal articulations used in total hip arthroplasty and hip resurfacing arthroplasty8,9, but to our knowledge, these reactions have not been described in MFN implants with metal-on-polyethylene articulations. We present two patients with MFN implants who developed partially cystic peri-implant soft-tissue masses with histologic features suggestive of metal hypersensitivity requiring revision arthroplasty. Both patients were informed that data concerning their cases would be submitted for publication, and they provided consent. Case 1. A sixty-three-year-old woman (body mass index, 31.3) with severe osteoarthritis had undergone a left total hip arthroplasty with a 50-mm Trilogy Shell (Zimmer, Warsaw, Indiana), a 36-mm highly crosslinked polyethylene liner (Zimmer), an uncemented titanium-alloy ABG II size-3 modular femoral stem with a 130° cobalt-chromium MFN (Stryker, Mahwah, New Jersey), and a +5-mm 36-mm cobalt-chromium head (Stryker). The patient had an uneventful postoperative course and was discharged on postoperative day three. Seven months later, the patient presented with progressive pain in the left hip. Radiographs showed satisfactory component positioning with no osteolysis, aseptic loosening, or periprosthetic fracture. Blood work showed an elevated erythrocyte sedimentation rate (ESR), C-reactive protein level (CRP), and serum metal ion levels without leukocytosis (Table I). Computed tomography (CT) of the hip demonstrated a 2.3 × 3-cm fluid collection between the gluteus maximus and medius muscles. Aspiration of the hip yielded 2 mL of orange-tainted …