The Hip-spine Assessment of a Novel Surgical Planning Software Provides Acetabular Component Targets That Are Reliable and in Agreement With Current Clinical Recommendations.

Background: Spinopelvic immobility has been reported to increase dislocation risk following total hip arthroplasty. Surgically placing acetabular components in a functional orientation has been shown to mitigate risk. The aim of this study was to evaluate the validity and reliability of novel surgical planning software to generate clinically recommended cup targets. Methods: Hip-spine assessments were performed retrospectively on 40 patients. Five reviewers, including 3 arthroplasty-trained surgical fellows and 2 clinical research scientists performed the assessments. Hip-spine assessments consisted of measuring anterior pelvic plane tilt, sacral slope, pelvic incidence, and lumbar lordosis on standing anteroposterior pelvis and lateral standing and seated hip-spine images. Generated cup targets and a control group (40°/20° relative to the anterior pelvic plane) were compared to clinically recommended cup targets. Agreement was defined as a cup position within the recommended range or within 3° of a specific target (eg, 40° inclination) when no range was provided. Intraclass correlation coefficients were used to assess interrater and intrarater reliability, and McNemar's chi-square test was used to measure success relative to the control group. Results: The intraclass correlation coefficient was 0.88 for delta sacral slope and 0.92 for pelvic incidence-lumbar lordosis mismatch. For patients with spinopelvic risk factors, the generated targets matched the clinical recommendations in 81% of patients compared to only 16% in the control group. Conclusions: Excellent interrater and intrarater reliability was achieved using the novel surgical planning software. The resultant target values agreed with clinical recommendations to a greater extent than the control group.

Patient-Reported Outcomes and Computed Tomography Review After Minimally Invasive Fusion of the Sacroiliac Joint With Aggressive Joint Decortication and Joint Compression.

The sacroiliac joint (SIJ) is a common, underrecognized source of low back pain. We evaluated outcomes in patients undergoing sacroiliac joint fusion (SIJF) using a novel, minimally invasive SIJF system emphasizing compressive forces across an aggressively debrided SIJ. We retrospectively reviewed data from a continuous set of patients presenting to a large, tertiary care hospital from September 2017 to August 2019. All patients received the novel SIJF device. Outcomes were assessed at 8 weeks, 6 months, and 12 months using the Oswestry Disability Index (ODI) score, Numerical Rating Scale (NRS) score, Single Assessment Numerical Evaluation (SANE) score, and Patient-Reported Outcomes Measurement Information System (PROMIS) measures, plus radiographic evaluation of fusion status. Data from 75 patients were analyzed. At 8 weeks, 6 months, and 12 months, the ODI score improved by 10.5 points (P=.002), 17.4 points (P<.0001), and 23.6 points (P<.0001), respectively, while the NRS score improved by 4.6 points (P<.0001), 4.4 points (P<.0001), and 4.6 points (P<.0001), respectively. SANE scores indicated high levels of patient satisfaction (81.0%, 92.18%, and 89.2%, respectively). PROMIS physical function scores improved by 2.65 points, 3.30 points, and 3.63 points, respectively, while PROMIS mental health scores showed changes of -1.93 points, 1.57 points, and -0.47 points, respectively. A review of computed tomography scans demonstrated grade 3 fusion (complete) in 81% of cases at a mean of 371 days postoperatively. There was one revision case for a malpositioned implant. The use of a novel SIJF device emphasizing compressive forces provided early, durable improvements in patient-reported outcomes and extremely high patient satisfaction. [Orthopedics. 2024;47(2):101-107.].

Improving alignment in total knee arthroplasty: a cadaveric assessment of a surgical navigation tool with computed tomography imaging.

PURPOSE: To investigate the accuracy of an imageless, optical surgical navigation tool to assist with femoral and tibial bone cuts performed during TKA. PATIENTS AND METHODS: Six board-certified orthopedic surgeons participated in a laboratory cadaver investigation, performing femoral and tibial bone cuts with the assistance of a computer navigation tool. Femoral and tibial varus/valgus, tibial slope, femoral flexion, and both femoral and tibial rotation measurements from the device were compared with angular measurements calculated from computed tomography (CT) images of the knees. RESULTS: Measurements with the navigation tool were highly correlated with those obtained from CT scans in all three axes. For the distal femoral cut, the absolute mean difference in varus/valgus was 0.83° (SD 0.46°, r = 0.76), femoral flexion was 1.91° (SD 1.16°, r = 0.85), and femoral rotation was 1.29° (SD 1.01°, r = 0.88) relative to Whiteside's line and 0.97° (SD 0.56°, r = 0.81) relative to the posterior condylar axis. For the tibia, the absolute mean difference in varus/valgus was 1.08° (SD 0.64°, r = 0.85), posterior slope was 2.78° (SD 1.40°, r = 0.60), and rotation relative to the anteroposterior axis (posterior cruciate ligament to the medial third of the tibial tuberosity) was 2.98° (SD 2.54°, r = 0.79). CONCLUSION: Utilization of an imageless navigation tool may aid surgeons in accurately performing and monitoring femoral and tibial bone cuts, and implant rotation in TKA and thus, more accurately align TKA components.

Reconstructing the value puzzle in health technology assessment: a pragmatic review to determine which modelling methods can account for additional value elements.

Health technology assessment (HTA) has traditionally relied on cost-effectiveness analysis (CEA) as a cornerstone of evaluation of new therapies, assessing the clinical validity and utility, the efficacy, and the cost-effectiveness of new interventions. The current format of cost-effectiveness analysis, however, does not allow for inclusion of more holistic aspects of health and, therefore, value elements for new technologies such as the impact on patients and society beyond its pure clinical and economic value. This study aimed to review the recent modelling attempts to expand the traditional cost-effectiveness analysis approach by incorporating additional elements of value in health technology assessment. A pragmatic literature review was conducted for articles published between 2012 and 2022 reporting cost-effectiveness analysis including value aspects beyond the clinical and cost-effectiveness estimates; searches identified 13 articles that were eligible for inclusion. These expanded modelling approaches mainly focused on integrating the impact of societal values and health equity in cost-effectiveness analysis, both of which were championed as important aspects of health technology assessment that should be incorporated into future technology assessments. The reviewed cost-effectiveness analysis methods included modification of the current cost-effectiveness analysis methodology (distributional cost-effectiveness analysis, augmented cost-effectiveness analysis, extended cost-effectiveness analysis) or the use of multi-criteria decision analysis. Of these approaches, augmented cost-effectiveness analysis appears to have the most potential by expanding traditional aspects of value, as it uses techniques already familiar to health technology assessment agencies but also allows space for incorporation of qualitative aspects of a product's value. This review showcases that methods to unravel additional value elements for technology assessment exist, therefore, patient access to promising technologies can be improved by moving the discussion from "if" to "how" additional value elements can inform decision-making.

Radiographic measurement of leg-length change in the nonoperative leg during total hip arthroplasty: a potential indicator of imaging error?

BACKGROUND: Anteroposterior (AP) pelvic radiographs are subject to errors that may cause measurement inaccuracy in total hip arthroplasty (THA). Such errors may be detected by measuring pre- to postoperative leg-length changes in the nonoperative leg, which experiences no physical changes during THA. METHODS: From AP pelvic radiographs, we measured pre- to postoperative leg-length changes (LLC) in the nonoperative legs of 67 patients who underwent primary THA using the trans-ischial line method. RESULTS: An LLC of 0 mm was observed in the nonoperative leg in only 14 cases (21%). A LLC ⩾ 2 mm was observed in 27% (18/67) of cases, including 13% (9/67) with LLC ⩾ 3 mm and 6% (4/67) with LLC ⩾ 4 mm. A post-hoc analysis used a validated method to measure change in pelvic tilt between pre- and postoperative images and found that changes in pelvic tilt ⩾ 4° in the anterior and posterior directions created apparent lengthening (2.0 ± 1.4 mm, p < 0.001 vs. 0-3° of tilt) and shortening (-2.1 ± 1.6 mm, p < 0.001 vs. 0-3° of tilt) of the nonoperative leg, respectively. CONCLUSIONS: The current study provides evidence of measurement errors in leg length using AP pelvic radiographs following THA. Changes in pelvic tilt may be in part responsible for these errors, with the direction of change in pelvic tilt influencing the apparent lengthening or shortening of the lower limb. Ultimately, these findings may influence the radiographic measurement and interpretation of leg-length changes following THA.

Computer-Assisted Navigation Accurately Delivers Preoperative Targets for Acetabular Component Orientation During Direct Anterior Approach Total Hip Arthroplasty.

Despite its success, total hip arthroplasty (THA) remains associated with potentially significant complications associated with component malposition. Preoperative planning can mitigate some of these potential concerns; however, the accurate intraoperative delivery of preoperative targets can be challenging. Computer-assisted navigation may assist with intraoperative target delivery, although the integration of these two technologies is relatively uncommon. We retrospectively reviewed cases of THA planned with a computed tomography-based preoperative planning software and performed with the use of an imageless, computer-assisted navigation system. Postoperative acetabular component orientation from radiographs was compared with preoperative targets and intraoperative navigation measurements. A total of 76 patients were included in the analysis. The mean anteversion target (20.0°±3.1°) did not differ significantly from the mean intraoperative navigation measurement (20.5°±3.3°; P=.30; mean difference, 2.2°±2.3°). The mean radiographic measurement (26.6°±6.5°) differed from the target by a mean of 7.5°±6.1° (P<.001). The mean inclination target (38.4°±1.9°) did not differ significantly from the mean intra-operative measurement (38.0°±1.5°; P=.20; mean difference, 1.3°±1.7°) but differed from the radiographic measurement by a mean of 5.2°±4.2° (41.8°±5.6°; P<.001). No adverse events were reported in the 90-day period following the index procedure. Our study demonstrated that an imageless navigation system can accurately deliver computed tomography-derived preoperative targets for acetabular component orientation. Differences noted on radiographs may be due to the difference in patient positioning for the postoperative imaging (standing) as compared with preoperative imaging or surgery itself (supine). [Orthopedics. 2023;46(4):218-223.].

The use of imageless navigation to quantify cutting error in total knee arthroplasty.

PURPOSE: Navigated total knee arthroplasty (TKA) improves implant alignment by providing feedback on resection parameters based on femoral and tibial cutting guide positions. However, saw blade thickness, deflection, and cutting guide motion may lead to final bone cuts differing from planned resections, potentially contributing to suboptimal component alignment. We used an imageless navigation device to intraoperatively quantify the magnitude of error between planned and actual resections, hypothesizing final bone cuts will differ from planned alignment. MATERIALS AND METHODS: A retrospective study including 60 consecutive patients undergoing primary TKA using a novel imageless navigation device was conducted. Device measurements of resection parameters were obtained via attachment of optical trackers to femoral and tibial cutting guides prior to resection. Following resection, optical trackers were placed directly on the bone cut surface and measurements were recorded. Cutting guide and bone resection measurements of both femoral and tibial varus/valgus, femoral flexion, tibial slope angles, and both femoral and tibial medial and lateral resection depths were compared using a Student's t-test. RESULTS: Femoral cutting guide position differed from the actual cut by an average 0.6 ± 0.5° (p = 0.85) in the varus/valgus angle and 1.0 ± 1.0° (p = 0.003) in the flexion/extension angle. The difference between planned and actual cut measurements for medial and lateral femoral resection depth was 1.1 ± 1.1 mm (p = 0.32) and 1.2 ± 1.0 mm (p = 0.067), respectively. Planned cut measurements based on tibial guide position differed from the actual cut by an average of 0.9 ± 0.8° (p = 0.63) in the varus/valgus angle and 1.1 ± 1.0° (p = 0.95) in slope angle. Measurement of medial and lateral tibial resection depth differed by an average of 0.1 ± 1.8 mm (p = 0.78) and 0.2 ± 2.1 mm (p = 0.85), respectively. CONCLUSIONS: Significant discrepancies between planned and actual femoral bone resection were demonstrated for flexion/extension angle, likely the result of cutting error. Our data highlights the importance of cut verification postresection to confirm planned resections are achieved, and suggests imageless navigation may be a source of feedback that would allow surgeons to intraoperatively adjust resections to achieve optimal implant alignment.

Use of Imageless Navigation in the Conversion of Hip Fusion to Total Hip Arthroplasty.

Conversion of hip arthrodesis to total hip arthroplasty is associated with significant challenges, including accurate restoration of leg length and proper orientation of the acetabular component. Computer-assisted navigation provides real-time data on these parameters that may be a useful augment during hip fusion takedown surgery. Here, we present the case of a 64-year-old woman who presented with symptoms related to a left hip arthrodesis. The patient underwent a left-sided hip arthrodesis takedown and conversion to a total hip arthroplasty (THA). Due to the altered anatomical architecture of the fused hip, imageless navigation was used to assist with the conversion to THA. This case demonstrates that in complex hip arthroplasty procedures, where anatomical morphology is altered, navigation technology can be beneficial in addressing the challenges of achieving optimal placement of acetabular components and establishing appropriate leg length and offset.

Discovery of the Selective Protein Kinase C-θ Kinase Inhibitor, CC-90005.

The PKC-θ isoform of protein kinase C is selectively expressed in T lymphocytes and plays an important role in the T cell antigen receptor (TCR)-triggered activation of mature T cells, T cell proliferation, and the subsequent release of cytokines such as interleukin-2 (IL-2). Herein, we report the synthesis and structure-activity relationship (SAR) of a novel series of PKC-θ inhibitors. Through a combination of structure-guided design and exploratory SAR, suitable replacements for the basic C4 amine of the original lead (3) were identified. Property-guided design enabled the identification of appropriately substituted C2 groups to afford potent analogs with metabolic stability and permeability to support in vivo testing. With exquisite general kinase selectivity, cellular inhibition of T cell activation as assessed by IL-2 expression, a favorable safety profile, and demonstrated in vivo efficacy in models of acute and chronic T cell activation with oral dosing, CC-90005 (57) was selected for clinical development.

Long-Term Outcomes of Single versus Multiple Courses of Viscosupplementation for Osteoarthritic Knee Pain: Real-World, Multi-Practice Experience Over a Six-Year Period.

INTRODUCTION: Viscosupplementation (VS) is a safe and effective local treatment for osteoarthritis (OA) of the knee. While much research has been completed evaluating its efficacy, comparatively little research has been completed examining the effects of multiple, repeat courses of treatment versus a single course of treatment. METHODS: We retrospectively reviewed real-world data from a large cohort of patients receiving treatment for OA of the knee at 16 rehabilitation clinics. Patients were grouped based on whether they received a single course of treatment or multiple courses. Outcomes for this study included pain (measured via the visual analog scale, VAS) and functional ability (measured via the Western Ontario and McMaster Universities Arthritis Index (WOMAC)). Pain and function scores were collected at baseline (prior to treatment administration) and one week following each course of treatment. RESULTS: Patients receiving multiple courses of treatment saw greater improvements than those receiving a single course. For VAS, maximal improvement occurred after the fourth course (66% improvement: 1.7±1.2 vs 5.0±2.4 at baseline, p<0.0001). WOMAC scores saw maximal improvement up to the fourth course for all domains (pain: 74%: 2.5±3.3 vs 9.5±5.3, p<0.0001; stiffness: 61%: 1.3±1.0 vs 3.3±2.0, p<0.0001; function: 66%: 9.5±7.2 vs 28.3±14.1, p<0.0001). When scores from multiple courses were averaged, improvements were maintained through the fourth course for VAS (3.4±2.8) and all WOMAC domains (pain: 6.1±5.0; stiffness: 3.0±2.2; function: 23.4±17.3). DISCUSSION: Our results indicate that multiple courses of treatment are associated with greater improvements than a single course of VS, and that these improvements continue through four courses of treatment.

Validation of a Novel Software Measurement Tool for Total Hip Arthroplasty.

Background Preoperative planning and postoperative evaluation of component position in total hip arthroplasty (THA) utilize specialized software that must be able to provide measurements that are both accurate and precise. A new software program for use in THA has recently been developed. We sought to evaluate the accuracy of this new software in comparison with two current, widely used software programs. Methodology Postoperative anteroposterior (AP) pelvic radiographs from 135 THA patients were retrospectively reviewed. Reference values for acetabular anteversion, inclination, and leg length were established using validated software programs (TraumaCad® as the primary reference value [PRV] and OsiriX LiteTM as the secondary reference value [SRV]). Measurements from the new software program (Intellijoint VIEWTM) were compared with reference values using Student's t-test and chi-square test. Results For anteversion, mean values for the PRV (27.34° ± 7.27°) and the new software (27.29° ± 7.21°) were not significantly different (p = 0.49). The new software differed from the PRV by a mean of 0.05° ± 0.93°. Similar results were noted for inclination, where the new software differed from the PRV and SRV by -0.13° ± 0.65° and 0.25° ± 1.26°, respectively (mean values: PRV: 43.62° ± 6.02°; SRV: 43.99° ± 6.27°; new software: 43.74° ± 6.17°; p = 0.87), and for leg length, where the new software differed from the PRV and SRV by 0.05 mm ± 0.46 mm and 0.22 mm ± 0.52 mm, respectively (mean values: PRV: 10.61 mm ± 11.60 mm; SRV: 10.77 mm ± 11.70 mm; new software: 10.56 mm - ± 11.61 mm; p = 0.98). Measurements were highly correlated across multiple reviewers (intraclass correlation coefficient ≥0.987). Conclusions The new software measurement tool is accurate and precise for assessing the acetabular component position and leg length measurements following THA in AP pelvic radiographs compared to currently used image measurement software.

Evaluating Alternate Registration Planes for Imageless, Computer-Assisted Navigation During Total Hip Arthroplasty.

BACKGROUND: Imageless computer navigation improves component placement accuracy in total hip arthroplasty (THA), but variations in the registration process are known to impact final accuracy measurements. We sought to evaluate the registration accuracy of an imageless navigation device during THA performed in the lateral decubitus position. METHODS: A prospective, observational study of 94 patients undergoing a primary THA with imageless navigation assistance was conducted. Patient position was registered using 4 planes of reference: the patient's coronal plane (standard method), the long axis of the surgical table (longitudinal plane), the lumbosacral spine (lumbosacral plane), and the plane intersecting the greater trochanter and glenoid fossa (hip-shoulder plane). Navigation measurements of cup position for each plane were compared to measurements from postoperative radiographs. RESULTS: Mean inclination from radiographs (41.5° ± 5.6°) did not differ significantly from inclination using the coronal plane (40.9° ± 3.9°, P = .39), the hip-shoulder plane (42.4° ± 4.7°, P = .26), or the longitudinal plane (41.2° ± 4.3°, P = .66). Inclination measured using the lumbosacral plane (45.8° ± 4.3°) differed significantly from radiographic measurements (P < .0001). Anteversion measured from radiographs (mean: 26.1° ± 5.4°) did not differ significantly from the hip-shoulder plane (26.6° ± 5.2°, P = .50). All other planes differed significantly from radiographs: coronal (22.6° ± 6.8°, P = .001), lumbosacral (32.5° ± 6.4°, P < .0001), and longitudinal (23.7° ± 5.2°, P < .0001). CONCLUSION: Patient registration using any plane approximating the long axis of the body provided a frame of reference that accurately measured intraoperative cup position. Registration using a plane approximating the hip-shoulder axis, however, provided the most accurate and consistent measurement of acetabular component position.

Surgical Approach and Reaming Depth Influence the Direction and Magnitude of Acetabular Center of Rotation Changes During Total Hip Arthroplasty.

BACKGROUND: Changes in acetabular or hip center of rotation (HCOR) commonly occur during acetabular component preparation during total hip arthroplasty (THA). HCOR displacement in mediolateral or superoinferior directions is known to influence offset and leg length, but the incidence and range of HCOR change in the anteroposterior direction is less understood as the sagittal plane cannot be measured on standard anteroposterior radiographs. This study assessed the 3-dimensional displacement of HCOR after cup implantation and evaluated for potential factors associated with increased acetabular component translations. METHODS: A total of 894 THAs were performed using a posterior, lateral, or direct anterior approach. Only intraoperative data from the navigation device were included in the analysis. All THAs performed between September 2015 and October 2017 were included. Paired t -tests were used to compare native HCOR and new HCOR values. RESULTS: The mean HCOR displacement in 3 directions was 4.97mm medially (P < .001), 0.83mm superiorly (P < .001), and 0.64mm posteriorly (P < .001). Subgroup analysis revealed greater posterior HCOR displacement with the anterior approach than the lateral/posterior approach (2.32mm vs 0.44mm; P < .001). Increasing medial HCOR displacement also resulted in increased superior and posterior HCOR displacement across surgical cases (P < .001). CONCLUSIONS: HCOR displacement is commonly observed in medial, superior, and posterior directions. HCOR changes are influenced by surgical approach, potentially secondary to patient positioning, with greater posterior HCOR displacement observed in anterior cases. Surgeons should be aware of these factors, particularly in cases with deficient or reduced posterior column bone stock.

Using Imageless Optical Navigation to Identify the New Hip Center in Crowe IV Dysplasia.

In total hip arthroplasty for patients with acetabular dysplasia, cup placement in the native acetabulum is preferred to placement in the pseudoacetabulum. Identifying the true acetabulum may prove challenging. In a patient with Crowe IV dysplasia, 3-dimensional mini-optical navigation was used to match the new hip center to the preoperative radiographic plan, which was identified to be 34 mm inferior to the pseudoacetabulum. This allowed titration of femoral shortening to 20 mm, to arrive at final limb lengthening of 14 mm. Although the use of other enabling technologies in hip dysplasia has been reported, to the authors' knowledge, this is the first reported case demonstrating the use of imageless optical navigation in this setting. It is a navigational tool with a small spatial footprint, does not mandate preoperative axial studies, and does not require multipoint bone surface registration. Imageless navigation may be a useful option for cup positioning and subsequent titration of femoral shortening in the reconstruction of Crowe IV dysplastic hips with degenerative joint disease. [Orthopedics. 2020; 43(2):e119-e122.].

The Disability Cascade: A Preventable Consequence of the Loss of Disc Height following Lumbar Microdiscectomy.

Lumbar discectomy is a mainstay surgical treatment for herniation of the lumbar discs and is effective at treating radicular symptomology. Despite the overall success of the procedure; the potential for reherniation and reoperation is significant. To avoid this potential recurrence, surgeons often perform discectomy more aggressively, removing a larger volume of nuclear material in the hopes of minimizing the likelihood of reherniation. This approach, while beneficial in minimizing the chance of reherniation, is associated with a volumetric reduction of the nucleus within the disc space, making the disc more prone to collapse and thus inducing a significant post-operative loss of disc height. While potentially minor in isolation, the loss of disc height, in fact, impacts several aspects of overall patient well-being. We hypothesize that the loss of disc height following discectomy causes an increase in pain and subsequent disability, the combination of which ultimately impacts socioeconomic factors affecting both the patient and the healthcare system as a whole. In this report, we outline the evidence in support of this disability cascade and provide recommendations on methods for limiting its impact. Given the current focus on cost-effectiveness in healthcare decision-making, methods for limiting this potentially damaging sequence of events must be investigated.

Accuracy of Acetabular Component Positioning Using Computer-assisted Navigation in Direct Anterior Total Hip Arthroplasty.

Background  Appropriate component positioning in total hip arthroplasty (THA) is imperative for long-term survivorship. C-arm fluoroscopy provides visual guidance in the direct anterior approach (DAA), but it is limited by qualitative properties. Conversely, imageless computer-assisted navigation systems (CAS) provide surgeons with intraoperative, three-dimensional (3D) quantitative measurements for cup position, although the accuracy of such systems has not been extensively addressed in the DAA. We evaluated the ability of an imageless CAS to deliver measurements for acetabular cup position with accuracy in the DAA. Materials and methods  A retrospective analysis of 69 primary THA procedures was conducted. Acetabular cup position measurements (anteversion and inclination) obtained intraoperatively by imageless navigation were compared to standard, postoperative anteroposterior pelvic radiographic measurements. Statistical comparisons were made using the Bland-Altman technique. Results  The mean difference between device and radiographic measurements for anteversion was 3.4° (standard deviation (SD): 4.1°; absolute mean difference (ABS): 4.2°), and 4.0° for inclination (SD: 3.6°; ABS: 4.3°). Bland-Altman analysis demonstrated excellent agreement; 93% (64/69) and 97% (67/69) of anteversion pairings fell within the statistical and clinical limits of agreement, whereas 94% (65/69) and 100% (69/69) of inclination pairings were within the statistical and clinical limits, respectively. Conclusions  Measurements obtained intraoperatively for acetabular cup position using imageless navigation in the DAA are agreeable with the current clinical standard.

Computer-assisted navigation as a diagnostic tool in revision total hip arthroplasty: A case report.

Revision total hip arthroplasty is a costly procedure accounting for approximately 14% of all hip arthroplasties. Compounding the cost considerations is the potential for serious injury to the patient when removing existing components. Such injury can result in not only increased morbidity but also dramatically increased costs. The use of computer-assisted navigation in revision total hip arthroplasty, while relatively uncommon, offers surgeons the ability to measure component position and orientation intraoperatively, thus allowing them the opportunity to modify their surgical plan, with the potential for decreasing both costs and iatrogenic injury. Here, we report a case of revision total hip arthroplasty where the use of computer-assisted navigation as a diagnostic tool allowed for intraoperative alterations in surgical plan and resulted in improved post-operative outcomes.

Predictors of bleeding complications following percutaneous image-guided liver biopsy: a scoping review.

PURPOSE: Percutaneous tissue biopsy is a mainstay of diagnostic and interventional radiology, providing a minimally invasive method for diagnosing malignant and benign disease. The purpose of this review was to collect and summarize the best available evidence regarding the risk factors associated with bleeding complications in image-guided liver biopsy. METHODS: A literature review was performed, searching Medline, EMBASE, CINAHL, the Cochrane Library, the National Institute for Health and Care Excellence (NICE) and Canadian Agency for Drugs and Technology in Health (CADTH) databases for any studies evaluating bleeding complications in image-guided liver biopsy. A total of 68 articles, published between January 1994 and April 2015, were reviewed in full, with 34 ultimately eligible for inclusion in the review. RESULTS: Bleeding of any kind occurred in up to 10.9% of image-guided liver biopsies, with major bleeding episodes ranging from 0.1% to 4.6% and minor bleeding events occurring in up to 10.9% of biopsies. The overall rate of bleeding was, however, found to be less than 2%. Several risk factors (patient, operator, and procedure-related) were identified as potentially indicative of an increased risk of post-biopsy bleeding. Patient-related risk factors included patient age (>50 years or <2 years), inpatient status (8/12 vs. 4/12, P < 0.001), comorbidities and/or concurrent diagnoses and coagulation status (rate of bleeding was 3.3% for international normalized ratio [INR] 1.2-1.5 vs. 7.1% for INR >1.5, P < 0.001). There was no consensus on impact of operator experience (>200 biopsies/year vs. <50/year) on post-biopsy bleeding rate. Procedure-related risk factors included needle size (cutting biopsy vs. fine needle aspiration, P < 0.001) and the presence of a patent track on post-biopsy ultrasound (P < 0.001). Lastly there was no difference found between targeted vs. nontargeted biopsies and number of needle passes. CONCLUSION: Reported rate of post-biopsy bleeding ranges between 0% and 10.9%, although the vast majority of studies reported bleeding rates under 2%. Several patient, operator, and procedure-related risk factors are associated with a higher risk of bleeding following liver biopsy.

A Novel Method for Correcting Pelvic Tilt on Anteroposterior Pelvic Radiographs.

Background Anteroposterior (AP) pelvic radiographs remain the standard for pre- and postoperative imaging during total hip arthroplasty (THA), despite the known limitation of plain films, including the inability to adequately account for distortion caused by variations in pelvic orientation such as pelvic tilt. The purpose of this study was to develop a reliable method for correcting pelvic tilt on AP pelvic radiographs in patients undergoing THA. Methods CT scans from 20 patients/cadaver specimens (10 male, 10 female) were used to create 3D renderings, from which synthetic radiographs of each pelvis were generated. For each pelvis, 13 synthetic radiographs were generated, showing the pelvis at between -30° and 30° of pelvic tilt, in 5° increments. On each image, eight unique parameters/distances were measured to determine the most appropriate parameters for the calculation of pelvic tilt. The most reliable and accurate of these parameters was determined via regression analysis and used to create gender-specific nomograms from which pelvic tilt measurements could be calculated. The accuracy and reliability of the nomograms and correction method were subsequently validated using both synthetic radiographs (n=50) and stereoradiographic images (n=58). Results Of the eight parameters measured, the vertical distance between the superior margin of the pubic symphysis and the transischial line (PSTI) was determined to be the most reliable (r=-0.96, ICC=0.94). Using that parameter and applying the associated nomograms to 50 synthetic radiographs of random pelvic tilt, the mean difference between the actual pelvic tilt and that calculated using the correction method was 0.1°±5.1° (p=0.98, r=0.96). In 58 stereoradiographic images, the mean difference between actual and measured pelvic tilt was -0.2°±6.4° (p=0.74, r=0.77). The pooled results indicate no significant difference between actual (2.2°±13.9°) and measured pelvic tilt (2.1°±14.3°, p=0.93, r=0.91). No significant differences were noted based on gender. Conclusions Our method of correcting for pelvic tilt using the vertical distance from the pubic symphysis to the transischial line provides a reliable method for correcting for pelvic tilt on AP pelvic radiographs.

Periacetabular osteotomy using an imageless computer-assisted navigation system: a new surgical technique.

Periacetabular osteotomy (PAO) is an effective surgical treatment for hip dysplasia. The goal of PAO is to reorient the acetabulum to improve joint stability, lessen contact stresses and slow the development of hip arthrosis. During PAO, the acetabulum is repositioned to adequately cover the femoral head. PAO preserves the weight-bearing posterior column of the pelvis, maintains the acetabular blood supply and retains the hip abductor musculature. The surgical technique needed to perform PAO is technically demanding, with correct repositioning of the acetabulum the most important-and challenging-aspect of the procedure. Imageless navigation has proven useful in other technically challenging surgeries, although its use in PAO has not yet been investigated. We have modified the standard technique for PAO to include the use of an imageless navigation system to confirm acetabular fragment position following osteotomy. Here, we describe the surgical technique and discuss the potential of this modified technique to improve patient-related outcomes.