Glenoid baseplate positioning for reverse total shoulder replacements (rTSR) is key for stability and longevity. 3D planning and image-derived instrumentation (IDI) are techniques for improving implant placement accuracy. This is a single-blinded randomised controlled trial comparing 3D planning with IDI jigs versus 3D planning with conventional instrumentation. Eligible patients were enrolled and had 3D pre-operative planning. They were randomised to either IDI or conventional instrumentation; then underwent their rTSR. 6 weeks post operatively, a CT scan was performed and blinded assessors measured the accuracy of glenoid baseplate position relative to the pre-operative plan. 47 patients were included: 24 with IDI and 23 with conventional instrumentation. The IDI group were more likely to have a guidewire placement within 2mm of the preoperative plan in the superior/inferior plane when compared to the conventional group (p=0.01). The IDI group had a smaller degree of error when the native glenoid retroversion was >10° (p=0.047) when compared to the conventional group. All other parameters (inclination, anterior/posterior plane, glenoids with retroversion <10°) showed no significant difference between the two groups. Both IDI and conventional methods for rTSA placement are very accurate. However, IDI is more accurate for complex glenoid morphology and placement in the superior-inferior plane. Clinically, these two parameters are important and may prevent long term complications of scapular notching or glenoid baseplate loosening. Image-derived instrumentation (IDI) is significantly more accurate in glenoid component placement in the superior/inferior plane compared to conventional instrumentation when using 3D pre-operative planning. Additionally, in complex glenoid morphologies where the native retroversion is >10°, IDI has improved accuracy in glenoid placement compared to conventional instrumentation. IDI is an accurate method for glenoid guidewire and component placement in rTSA

Accurate 3D pre-operative planning shows significance of improving the precision of Total Hip Arthroplasty (THA) and Total Knee Arthroplasty (TKA). Since CT acquisition leads to high radiation exposure to patients, it is clinically desirable to find an alternative to CT scan for planning THA or TKA such as patient-specific 2D–3D reconstruction from a limited number of 2D calibrated X-ray images acquired with much lower radiation dose e.g. EOS imaging. Feature-based 2D–3D non-rigid registration based on the construction of statistical shape model (SSM) as a priori has been applied to reconstruct the surface models of proximal femur, and also the surface reconstruction of lower extremity for TKA has been validated in a cadaveric study by Zheng et al. On the other hand, intensity-based 2D–3D non-rigid registration can reconstruct the patient-specific intensity volumes like CTs to allow an insight into lower extremity morphology such as intramedullary anatomy, which can provide more comprehensive information in routine clinical practice. In this study, we will present an atlas- based 2D–3D reconstruction method and introduce its application to reconstruct the intensity volumes of lower extremity. Moreover, we take the articulation in the knee joint into consideration so as to avoid the penetration between femur and tibia which is favourable for the pre-operative planning. The results of the experiments demonstrated the efficacy of the proposed method on reconstructing the lower extremity morphology as well as the intramedullary canal anatomy

Purpose. Arthritis is the most common chronic illness in the United States. TKR provides reliable pain relief and improved function for patients with advanced knee arthritis. Total joint replacement now represents the greatest expense in the national healthcare budget. Surgical costs are driven by two key components: fixed and variable costs. Patient Specific Instruments™ (PSI, Zimmer, Warsaw, IN, USA) has the potential to reduce both fixed and variable costs by shortening operative time and reducing surgical instrumentation. However, PSI requires the added costs of pre-operative MRI scanning and fabrication of custom pin guides. Previous studies have shown reduction in operating room times and required instrumentation, but question the cost-effectiveness of the technology. Also, these studies failed to show improvement in coronal alignment, but call for additional studies to determine any improvement in clinical function and patient satisfaction. Our pilot study aims to compare the incremental PSI costs to fixed and variable OR cost savings, and compare meaningful patient and clinical outcomes between PSI and standard TKR surgeries. Methods. This IRB approved, prospective, randomized pilot trial involves 20 TKR patients. Inclusion criteria includes: diagnosis of osteoarthritis, ability to undergo MRI, and consent for primary TKR. Following informed consent, patients are randomized to PSI or standard TKR. Patients randomized to PSI undergo pre-operative non-contrast MRI of the affected knee at least 4 weeks prior to surgery. Custom pin guides are prototyped from 3D pre-operative planning software customizable to individual surgeon and patient. All surgeries will be completed by a single surgeon (DA), using a medial parapatellar arthrotomy and Zimmer Nexgen™ implants. Surgical technique for PSI patients utilizes custom pin guides to determine placement of the femoral and tibial cutting guides, whereas an intramedullary femoral rod and extramedullary tibial guide are used in standard TKR patients. Our pilot study will compare numerous intra-operative and post-operative variables between the two patient cohorts. Intra-operative variables include: bony cutting time, tourniquet time, total OR time, surgical instrumentation, and bony resection height. Post-operative variables include: instrument processing and sterilization, blood transfusion, pain medication usage, length of stay, complications (including hospital readmission), and patient reported outcomes (SF-36, WOMAC, and satisfaction) at 4 weeks, 6 months, and 1 year. Additional economic sensitivity analyses using hospital and national cost-to-charge figures will quantify the potential added revenue or costs of implementing the PSI system. Discussion. This pilot study will illustrate the potential benefits of the PSI technology. To our knowledge no clinical trials have been published on the PSI system. Former studies have neglected to include meaningful clinical and patient outcomes, which could potentially add to the cost savings of the technology through reduced blood transfusions, length of stay, and hospital readmission. Additionally, improved rotational alignment may produce superior patient function and satisfaction. Studies recently published on alternative patient-specific TKR systems question the cost-effectiveness and technical improvement of patient-specific instrumentation. Although our sample size may fail to produce statistical significance, the consummate measurement of all the proposed hospital, surgical, and patient factors will inform future randomized multicenter trials

Introduction. At present, orthopaedic surgeons utilize either CT, MRI or X-ray for imaging a joint. Unfortunately, CT and MRI are quite expensive, non weight-bearing and the orthopaedic surgeon does not receive revenue for these procedures. Although x-rays are cheaper, similar to CT scans, patients incur radiation. Also, all three of these imaging modalities are static. More recently, a new ultrasound technology has been developed that will allow a surgeon to image their patients in 3D. The objective of this study is to highlight the new opportunity for orthopaedic surgeons to use 3D ultrasound as alternative to CT, MRI and X-rays. Methods. The 3D reconstruction process utilizes statistical shape atlases in conjunction with the ultrasound RF data to build the patient anatomy in real-time. The ultrasound RF signals are acquired using a linear transducer. Raw RF data is then extracted across each scan line. The transducer is tracked using a 3D tracking system. The location and orientation for each scan line is calculated using the tracking data and known position of the tracker relative to the signal. For each scan line, a detection algorithm extracts the location on the signal of the bone boundary, if any exists. Throughout the scan process, a 3D point cloud is created for each detected bone signal. Using a statistical bone atlas for each anatomy, the patient specific surface is reconstruction by optimizing the geometry to match the point cloud. Missing regions are interpolated from the bone atlas. To validate reconstructed models output models are then compared to models generated from 3D imaging, including CT and MRI. Results. 3D ultrasound, which now has FDA approval in the United States, is presently available for an orthopaedic surgeon to use. Error analyses have been conducted in comparison to MRI and CT scans and revealed that 3D ultrasound has a similar accuracy of less than 1.0 mm in the creation of a 3D bone and soft-tissues. Unlike CT and MRI scans that take in excess of 2–3 weeks to create human bones, 3D ultrasound creates bones in 4–6 minutes. Once the bones are created, the surgeon can assess bone quality, ligament and cartilage conditions, assess osteophytes, fractures and guide needles into the 3D joint space. The creation of 3D bones has been accurately assessed for the spine, shoulder, knee, hip and ankle joints. A 3D joint pre-operative planning module has also been developed for a surgeon to size and position components before surgery. Discussion. 3D ultrasound is an exciting new imaging technology available for orthopaedic surgeons to use in their practice. Existing CPT codes are readily available for 3D ultrasound procedures. A surgeon can now evaluate and diagnose bone and soft- tissue conditions, in 3D, using ultrasound, which is safer and is an easier procedure compared to CT, MRI and X-rays. This new ultrasound technology is a highly accurate imaging technique that will allow a surgeon to diagnose bone and soft-tissue concerns in 3D, under weight-bearing, dynamic conditions and guide needle injections to correct location, in 3D