Harpal S. Khanuja

Bio: Harpal S. Khanuja is an academic researcher from Johns Hopkins University. The author has contributed to research in topics: Medicine & Arthroplasty. The author has an hindex of 25, co-authored 108 publications receiving 2012 citations. Previous affiliations of Harpal S. Khanuja include Johns Hopkins University School of Medicine & Johns Hopkins Bayview Medical Center.

Cementless femoral fixation in total hip arthroplasty.

Abstract: A number of cementless femoral stems are associated with excellent long-term survivorship. Cementless designs differ from one another in terms of geometry and the means of obtaining initial fixation. Strict classification of stem designs is important in order to compare results among series. Loosening and thigh pain are less prevalent with modern stem designs. Stress-shielding is present in most cases, even with newer stem designs.

Short bone-conserving stems in cementless hip arthroplasty.

Abstract: ➤ Short bone-conserving femoral stems in total hip arthroplasty were designed to preserve proximal bone stock. ➤ Given the distinct fixation principles and location of loading among these bone-conserving stems, a classification system is essential to compare clinical outcomes. ➤ Due to the low quality of currently available evidence, only a weak recommendation can be provided for clinical usage of certain stem designs, while some other designs cannot be recommended at this time. ➤ A high prevalence of stem malalignment, incorrect sizing, subsidence, and intraoperative fractures has been reported in a subset of these short stem designs. ➤ Stronger evidence, including prospective multicenter randomized trials comparing standard stems with these newer designs, is necessary before widespread use can be recommended.

Perioperative blood transfusions in orthopaedic surgery.

Abstract: ➤ Blood transfusion after orthopaedic surgery accounts for 10% of all packed red blood-cell transfusions, but use varies substantially across hospitals and surgeons. ➤ Transfusions can cause systemic complications, including allergic reactions, transfusion-related acute lung injury, transfusion-associated circulatory overload, graft-versus-host disease, and infections. ➤ Tranexamic acid is a new cost-effective blood management tool to reduce blood loss and decrease the risk of transfusion after total joint arthroplasty. ➤ Current clinical evidence does not justify transfusions for a hemoglobin level of >8 g/dL in the absence of symptoms. ➤ Studies have also supported the use of this trigger in patients with a history or risk of cardiovascular disease.

Real-time image-guided placement of anchor devices

Abstract: A real-time positioning system monitors and displays a real-time position and orientation (pose) of a surgical device relative to reference device and internal structures of a subject during a medical procedure. Tracking targets are affixed to a surgical device and a reference device. The reference device is fixed to a target site of a subject. The tracked targets are interactively monitored by a tracking device and their raw positions are converted to a position and orientation (pose) of the surgical device and the reference device. A medical imaging device acquires images of internal structures of the subject which is converted into computer models by a modeling engine. The models of internal structures are correctly registered with models of the surgical instrument and the reference device into a single interactive representation assisting a surgeon in a medical procedure. A density integrator may be employed to select a best path through a subject based upon user-defined criteria, such as greatest overall density, least density, furthest from nerves, blood vessels, intersecting the most diseased tissue, etc.

In vitro simulation. Early results of stereotaxy for pedicle screw placement.

Abstract: Study design Frameless stereotaxy with doppler ultrasound and three dimensional computer model registration is assessed in vitro for pedicle screw placement. Objective To identify feasibility of pedicle screw navigation and placement using this technology. Summary of background data Inaccurate pedicle screw placement can lead to neurovascular injury or suboptimal fixation. Present techniques in pedicle screw placement involve only confirmation of hole orientation. Method Forty-four pedicle screws were placed in lumbosacral models and cadaver specimens. Accuracy was assessed with a computed tomography scan and vertebral cross sectioning. Results All screws were intrapedicular. Accuracy of anterior cortical fixation was 1.5 mm, with a range of 2.5 mm. Conclusion In vitro frameless stereotaxy is accurate for pedicle screw placement. This technology adds a component of navigation to pedicle screw placement.

Atypical subtrochanteric and diaphyseal femoral fractures: Report of a task force of the american society for bone and mineral Research

Abstract: Reports linking long-term use of bisphosphonates (BPs) with atypical fractures of the femur led the leadership of the American Society for Bone and Mineral Research (ASBMR) to appoint a task force to address key questions related to this problem. A multidisciplinary expert group reviewed pertinent published reports concerning atypical femur fractures, as well as preclinical studies that could provide insight into their pathogenesis. A case definition was developed so that subsequent studies report on the same condition. The task force defined major and minor features of complete and incomplete atypical femoral fractures and recommends that all major features, including their location in the subtrochanteric region and femoral shaft, transverse or short oblique orientation, minimal or no associated trauma, a medial spike when the fracture is complete, and absence of comminution, be present to designate a femoral fracture as atypical. Minor features include their association with cortical thickening, a periosteal reaction of the lateral cortex, prodromal pain, bilaterality, delayed healing, comorbid conditions, and concomitant drug exposures, including BPs, other antiresorptive agents, glucocorticoids, and proton pump inhibitors. Preclinical data evaluating the effects of BPs on collagen cross-linking and maturation, accumulation of microdamage and advanced glycation end products, mineralization, remodeling, vascularity, and angiogenesis lend biologic plausibility to a potential association with long-term BP use. Based on published and unpublished data and the widespread use of BPs, the incidence of atypical femoral fractures associated with BP therapy for osteoporosis appears to be very low, particularly compared with the number of vertebral, hip, and other fractures that are prevented by BPs. Moreover, a causal association between BPs and atypical fractures has not been established. However, recent observations suggest that the risk rises with increasing duration of exposure, and there is concern that lack of awareness and underreporting may mask the true incidence of the problem. Given the relative rarity of atypical femoral fractures, the task force recommends that specific diagnostic and procedural codes be created and that an international registry be established to facilitate studies of the clinical and genetic risk factors and optimal surgical and medical management of these fractures. Physicians and patients should be made aware of the possibility of atypical femoral fractures and of the potential for bilaterality through a change in labeling of BPs. Research directions should include development of animal models, increased surveillance, and additional epidemiologic and clinical data to establish the true incidence of and risk factors for this condition and to inform orthopedic and medical management. © 2010 American Society for Bone and Mineral Research.

Navigation system for cardiac therapies

Abstract: An image guided catheter navigation system for navigating a region of a patient includes an imaging device, a tracking device, a controller, and a display. The imaging device generates images of the region of the patient. The tracking device tracks the location of the catheter in the region of the patient. The controller superimposes an icon representing the catheter onto the images generated from the imaging device based upon the location of the catheter. The display displays the image of the region with the catheter superimposed onto the image at the current location of the catheter.

Atypical Subtrochanteric and Diaphyseal Femoral Fractures: Report of a Task Force of the American Society for Bone and Mineral Research Running Title: Atypical Femoral Fractures Task Force Report

Abstract: Introduction: Reports linking long-term use of bisphosphonates (BPs) with atypical fractures of the femur led the leadership of the American Society for Bone and Mineral Research (ASBMR) to appoint a Task Force to address key questions related to this problem. Methods: A multi-disciplinary expert group reviewed pertinent published reports concerning atypical femur fractures, as well as pre-clinical studies that could provide insight into their pathogenesis. Results and Conclusions: A case definition was developed so that subsequent studies report on the same condition. The Task Force defined major and minor features of complete and incomplete atypical femoral fractures and recommends that all major features, including their location in the subtrochanteric region and femoral shaft, transverse or short oblique orientation, minimal or no associated trauma and absence of comminution, be present to designate a femoral fracture as atypical. Minor features include their associations with cortical thickening, a periosteal reaction of the lateral cortex, a medial spike when the fracture is complete, prodromal pain, bilaterality, comorbid conditions and concomitant drug exposures, including BPs, other antiresorptive agents, glucocorticoids and proton pump inhibitors. Preclinical data evaluating the effects of BPs on collagen cross-linking and maturation, accumulation of microdamage and advanced glycation end-products, mineralization, remodeling, vascularity and angiogenesis, lend biological plausibility to a potential association with long-term BP use. Based on published and unpublished data and the widespread use of BPs, the incidence of atypical femoral fractures associated with BP therapy for osteoporosis appears to be very low, particularly compared to the number of vertebral, hip and other fractures that are prevented by BPs. Moreover, a causal association between BPs and atypical fractures has not been established. However, recent observations suggest that the risk rises with increasing duration of exposure and there is concern that lack of awareness and under-reporting may mask the true incidence of the problem. Recommendations: Given the relative rarity of atypical femoral fractures, the Task Force recommends that specific diagnostic and procedural codes be created and that an international registry be established to facilitate studies of the clinical and genetic risk factors and optimal surgical and medical management of these fractures. Physicians and patients should be made aware of the possibility of atypical femoral fractures and of the potential for bilaterality through a change in labeling of BPs. Research directions should include development of animal models, increased surveillance and additional epidemiological and clinical data to establish the true incidence of and risk factors for this condition and to inform orthopaedic and medical management.

Method and apparatus for surgical navigation

Abstract: A surgical navigation system for navigating a region of a patient includes a non-invasive dynamic reference frame and/or fiducial marker, sensor tipped instruments, and isolator circuits. The dynamic reference frame may be repeatably placed on the patient in a precise location for guiding the instruments. The instruments may be precisely guided by positioning sensors near moveable portions of the instruments. Electrical sources may be electrically isolated from the patient.

Haptic guidance system and method

Abstract: A surgical apparatus includes a surgical device, configured to be manipulated by a user to perform a procedure on a patient, and a computer system. The computer system is programmed to implement control parameters for controlling the surgical device to provide at least one of haptic guidance to the user and a limit on user manipulation of the surgical device, based on a relationship between an anatomy of the patient and at least one of a position, an orientation, a velocity, and an acceleration of a portion of the surgical device, and to adjust the control parameters in response to movement of the anatomy during the procedure.