The use of Patient Reported Outcome Measures (PROMS) has been critical to the success of total joint arthroplasty (TJA). They have made possible the evaluations of new implants, materials and surgical techniques that have been essential to the development of these technologies. PROMS have had a major impact on the decisions that surgeons make regarding treatment and care of patients. However, there are serious limitations of PROMS. They are useless in the first few weeks after surgery. They provide very little objective functional information to which health care providers can respond in the early, critical post-operative period. PROMS do not objectively measure specific outcome measures (e.g. ROM, distance walked). PROMS are also cumbersome and time consuming to use. Joint specific surface sensors are emerging to allow objective measurements of specific functional outcomes of knee surgery. This allows an examination of the factors that might affect these functional outcomes. The purpose of this study was to examine the relationship of age, gender, BMI and pain following TKA on ROM and activity measured using a joint specific surface sensor.

Background

Total Knee Arthroplasty (TKA) provides patients with significant improvements in quality of life. Subjective patient reported outcome measures (PROMs) are traditionally used to measure preoperative functional status and postoperative outcomes. However, there are limitations to PROMs. In particular, they provide virtually no functional information in the first 3 weeks after surgery, which could be used to guide the patient's recovery. Newly available wearable electronic sensors make it possible to: 1) measure important functional outcomes following TKA; 2) guide the patient's physical therapy (PT); and 3) provide real-time functional and clinical information to the provider.

Compliance with PT after TKA is a challenge. Patients cite time, transportation, and cost as deterrents to PT appointments. However, an intensive PT program is essential in TKA. Surface sensor devices may be able to increase PT compliance by guiding patients through exercises at home. Additionally, these devices can transmit PT progress in real-time to the providers, allowing them to monitor and assist the patient's recovery.

Our study investigates the feasibility of using a surface sensor device (TracPatch™) on patients following TKA. We sought to answer the following questions: 1) Will patients tolerate the device; 2) Will patients comply with device instructions; 3) Will patients be able to use the smart phone application; 4) Will the device collect, transmit, and store data as it was designed? We believe these fundamental questions must be answered as we enter the era of personal sensor-measured functional outcomes.

Background

Total hip arthroplasty (THA) is a highly successful procedure, yet access to arthroplasty is limited in many developing nations. In response, organizations around the world have conducted service trips to provide international arthroplasty care to underserved populations. Little outcomes data are currently available related to these trips. We present a 1-year follow up.

Introduction

Neck-stem corrosion has been associated with Adverse Local Tissue Reaction (ALTR) in dual-taper femoral stems. Several diagnostic tests, of varying specificity and sensitivity, are used to identify ALTR. The purpose of this study was to document the clinical presentation, diagnostic workup and surgical findings in a large cohort of patients with dual modular stems, and use this information to propose an evaluation protocol that assists surgical decision-making.

Introduction

The goal of tibial tray placement in total knee arthroplasty (TKA) is to maximize tibial surface coverage while maintaining proper rotation. Maximizing tibial surface coverage without component overhang reduces the risk of tibial subsidence. Proper tibial rotation avoids excess risk of patellar maltracking, knee instability, inappropriate tibial loading, and ligament imbalance. Different tibial tray designs offer varying potential in optimizing the relationship between tibial surface coverage and rotation. Patient specific instrumentation (PSI) generates customized guides from an MRI- or CT-based preoperative plan for use in TKA. The purpose of the present study was to utilize MRI information, obtained as part of the PSI planning process, to determine, for anatomic, symmetric, and asymmetric tibial tray designs, (1) which tibial tray design achieves maximum coverage, (2) the impact of maximizing coverage on rotation, and (3) the impact of establishing neutral rotation on coverage.

Introduction

Total knee arthroplasty is effective for the management of osteoarthritis of the knee. Conventional techniques utilizing manual instrumentation (MI) make use of intramedullary femoral guides and either extramedullary or intramedullary tibial guides. While MI techniques can achieve excellent results in the majority of patients, those with ipsilateral hardware, post-traumatic deformity or abnormal anatomy may be technically more challenging, resulting in poorer outcomes. Computer-assisted navigation (CAN) is an alternative that utilizes fixed trackers and anatomic registration points, foregoing the need for intramedullary guides. This technique has been shown to yield excellent results including superior alignment outcomes compared to MI with fewer outliers. However, studies report a high learning curve, increased expenses and increased operative times. As a result, few surgeons are trained and comfortable utilizing CAN. Patient-specific instrumentation is an alternative innovation for total knee arthroplasty. Custom guide blocks are fabricated based on a patient's unique anatomy, allowing for the benefits of CAN but without the increased operative times or the high learning curve. In this study we sought to evaluate the accuracy of PSI techniques in patients with previous ipsilateral hardware of the femur.

Introduction

Patient specific instrumentation (PSI) generates customized guides from an MRI- or CT-based preoperative plan for use in total knee arthroplasty (TKA). PSI software executes the preoperative planning process. Several manufacturers have developed proprietary PSI software for preoperative planning. It is possible that each proprietary software has a unique preoperative planning process, which may lead to variation in preoperative plans among manufactures and thus variation in the overall PSI technology. The purpose of this study was to determine whether different PSI software generate similar preoperative plans when applied to a single implant system and given identical MR images.

Introduction:

Total knee arthroplasty (TKA) is an effective operation for the management of osteoarthritis of the knee. Conventional technique utilizing manual instrumentation (MI) allows for reproducible and accurate execution of the procedure. The most common techniques make use of intramedullary femoral guides and either extrameduallary or intrameduallary tibial guides. While these methods can achieve excellent results in the majority of patients, those with ipsilateral hardware, post-traumatic deformity or abnormal anatomy may preclude the accurate use of these techniques.

Patient-specific instrumentation (PSI) is an alternative innovation for total knee arthroplasty. Utilizing magnetic resonance imaging (MRI) or computed tomography (CT), custom guide blocks are fabricated based on a patient's unique anatomy. This allows for the benefits of computer assisted navigation (CAN) but without the increased operative times or the high learning curve associated with it. Furthermore it allows the use of familiar cutting blocks and guides to check the accuracy of the PSI guide blocks. In this study we sought to evaluate the accuracy of PSI techniques in patients with previous ipsilateral hardware, which would make the use of MI technically challenging and possibly subject to inaccuracy.

Introduction:

The addition of neck-stem modularity of femoral components allowed for increased versatility in controlling stability, head center, and limb length in total hip arthroplasty (THA). Recent reports of neck-stem corrosion, complicated by adverse local tissue reaction, have raised concern and prompted further patient evaluation for revision arthroplasty.

Introduction:

Patient specific instrumentation (PSI) is an innovative technology in total knee arthroplasty. With the use of a preoperative MRI or CT scan, custom guide blocks are individually manufactured for each patient. Contrary to other TKA technologies such as computer-assisted surgery, PSI utilizes measured resection technique rather than a primarily ligament balancing technique. This has the potential to negatively affect the operating surgeon's ability to achieve optimal soft tissue balancing, which is especially critical in patients with severe lower extremity malalignment. Despite early research suggesting that PSI is accurate, has a low learning curve, and can reduce OR time, it remains unclear whether a surgeon using PSI can achieve optimal soft tissue balancing using a measured resection technique. The purpose of this study is to evaluate the efficacy of PSI in patients with severe preoperative limb alignment deformities.

Introduction:

Patient specific instrumentation (PSI) generates customized guides from a magnetic resonance imaging based preoperative plan for use in total knee arthroplasty (TKA). PSI software must be able to accommodate differences in implant design. The purpose of the present study was to determine whether any differences in the accuracy of limb alignment, component alignment, component sizing, or bony resection could be identified in patients undergoing PSI TKA with identical PSI software and one of two different implant systems.

Introduction

Modular femoral necks have shown promising clinical results in total hip arthroplasty (THA) to optimize offset, rotation, and leg length. Given the wide variety of proximal femoral morphology, fine-tuning these kinematic parameters can help decrease femoroacetabular impingement, decrease wear rates and help prevent dislocations. Yet, additional implant junctions introduce additional mechanisms of failure. We present two patients who developed an abnormal soft tissue reaction consistent with a metal hypersensitivity reaction at a modular femoral neck/stem junction requiring revision arthroplasty.

Introduction

The use of short stems has been growing in THA for the past five years. As a result, a large number of short stem designs are available in the market place. However, fixation points differ for many of the designs resulting in different radiographic modeling creating confusion when trying to collate to clinical findings. We have created a classification system in an attempted to provide clarity in analyzing radiographic and clinical findings.

Introduction

Patient specific instruments (PSI) and computer-assisted surgery (CAS) are innovative technologies that offer the potential to improve the accuracy and reproducibility with which a total knee arthroplasty (TKA) is performed. It has not been established whether clinical, functional, or radiographic outcomes between PSI, CAS, and manual TKA differ in the hands of an experienced TKA surgeon. The purpose of this study was to evaluate clinical, functional and radiographic outcomes between TKA performed with PSI, CAS, and manual instruments at short-term follow-up. Our hypothesis was that at early follow-up, we would be unable to elucidate any significant differences between the groups using the most commonly utilized outcomes measures.

Introduction

Proper femoral component rotation is a crucial factor in successful total knee arthroplasty (TKA). Femoral component rotation using anatomic landmarks has traditionally been established by referencing the transepicondylar axis (TEA), Whiteside's Line (WSL), or the posterior condylar axis (PCA). TEA is thought to best approximate the flexion-axis of the knee, however WSL or PCA are commonly used as surrogates of the TEA in the operating room due to their accessibility. The relationship of these anatomic landmarks has been previously investigated in anatomic and computed tomography based studies. The relatively few knees evaluated have limited the power of these studies. Patient Specific Instrumentation (PSI) utilizing magnetic resonance imaging (MRI) is an emerging technology in total knee replacement. The purpose of this study was to use magnetic resonance imaging based planning software to assess the relationship of WSL and PCA to the TEA and to determine if the relationships were influenced by the magnitude of the pre-operative coronal deformity.

Introduction

Readmission after Total Hip Arthroplasty (THA) or Total Knee Arthroplasty (TKA) places a great burden on the health care system. As reimbursement systems place increased emphasis on quality measures such as readmission rates, understanding the causes for readmission becomes increasingly important.

Introduction

Many uncemented femoral implant designs have had successful outcomes in total hip arthroplasty (THA). Different uncemented stem designs achieve initial and long term stability through shape, size, coating and fit. There is increasing emphasis on bone preservation, particularly in younger and more active patients. The desire to optimize load transfer has led to the development of short stems that seek to achieve fixation in the proximal femur. Short stems designed to achieve stability by engaging the metaphysis or the proximal femoral necks are currently in clinical use. The purpose of this study was to examine the extent to which five stems designed to achieve proximal fixation contact the bone in the proximal femur. Using three-dimensional CT models of 30 femurs, we assessed the fit, fill and contact of each of the five different implants.

Introduction

Computer-assisted surgery (CAS) is a tool developed to allow accurate limb and implant alignment in TKA. The strength of the technology is that it allows the surgeon to assess soft tissue balance and ligament laxity in flexion and extension. The accuracy of this ligament balancing technology depends upon an accurate determination of femoral component size. This size is established with intraoperative surface registration techniques. Customized instrumentation (CI) is a measured resection technique in which component size is established on preoperative 3D MRI reconstructions. The purpose of this study is to determine how these two computer-based technologies compare with regard to the accuracy with which femoral component size is established in TKA.

Introduction

Custom instrumentation in TKA utilizes pre-operative imaging to generate a customized guide for cutting block placement (Figure 1). The surgeon is able to modify the plan using three-dimensional software (Figure 2). Although this technology is increasingly gaining acceptance, there is a paucity of clinical data supporting it.

Introduction

Readmission after Total Hip Arthroplasty (THA) or Total Knee Arthroplasty (TKA) places a great burden on the health care system. As reimbursement systems place increased emphasis on quality measures such as readmission rates, identifying and understanding the most common drivers for readmission becomes increasingly important.