Active robotics for total knee Arthroplasty (TKA) uses a CAD-CAM approach to plan the correct size and placement of implants and to surgically achieve planned limb alignment. The TSolution One Total Knee Application (THINK Surgical Inc., Fremont, CA) is an open-implant platform, CT-based active robotic surgical system. A multi-center, prospective, non-randomized clinical trial was performed to evaluate safety and effectiveness of robotic-assisted TKA using the TSolution One Total Knee Application. This report details the findings from the IDE. Patients had to be ≥ 21 years old with BMI ≤ 40, Kellgren-Lawrence Grade ≥ 3, coronal deformity ≤ 20°, and sagital flexion contracture ≤ 15° to participate. In addition to monitoring all adverse events (AE), a pre-defined list of relevant major AEs (medial collateral ligament injury, extensor mechanism disruption, neural deficit, periprosthetic fracture, patellofemoral dislocation, tibiofemoral dislocation, vascular injury) were specifically identified to evaluate safety. Bleeding complications were also assessed. Malalignment rate, defined as the percentage of patients with more than a ± 3° difference in varus-valgus alignment from the preoperative plan, was used to determine accuracy of the active robotic system. Knee Society Scores (KSS) and Short Form 12 (SF-12) Health Surveys were assessed as clinical outcome measures. Results were compared to published values associated with manual TKA.Introduction
Methods
Improper soft-tissue balancing can result in postoperative complications after total knee arthroplasty (TKA) and may lead to early revision. A single-use tibial insert trial with embedded sensor technology (VERASENSE from OrthoSensor Inc., Dania Beach, FL) was designed to provide feedback to the surgeon intraoperatively, with the goal to achieve a “well-balanced” knee throughout the range of motion (Roche et al. 2014). The purpose of this study was to quantify the effects of common soft-tissue releases as they related to sensor measured joint reactions and kinematics. Robotic testing was performed using four fresh-frozen cadaveric knee specimens implanted with appropriately sized instrumented trial implants (geometry based on a currently available TKA system). Sensor outputs included the locations and magnitudes of medial and lateral reaction forces. As a measure of tibiofemoral joint kinematics, medial and lateral reaction locations were resolved to femoral anterior-posterior displacement and internal-external tibial rotation (Fig 1.). Laxity style joint loading included discrete applications of ± 100 N A-P, ± 3 N/m I-E and ± 5 N/m varus-valgus (V-V) loads, each applied at 10, 45, and 90° of flexion. All tests included 20 N of compressive force. Laxity tests were performed before and after a specified series of soft-tissue releases, which included complete transection of the posterior cruciate ligament (PCL), superficial medial collateral ligament (sMCL), and the popliteus ligament (Table 1). Sensor outputs were recorded for each quasi-static test. Statistical results were quantified using regression formulas that related sensor outputs (reaction loads and kinematics) as a function of tissue release across all loading conditions. Significance was set for p-values ≤ 0.05.Introduction
Methods
Early developments of computer assisted TKA focused on improving the technical aspects of proper registration, improved ease of use of instrumentation to ensure proper placement of cutting blocks and implants, and to document the technical improvements in alignment that come with the use of these technologies. There was minimal adoption of these technologies, as costs have been high and measured improvement in outcomes has not been demonstrated. Patient specific instrumentation (PSI), involving preoperative three dimensional imaging and engineering of patient specific guides have been more actively embraced by the orthopaedic community – with industry embracing the technology and promoting it vigorously. This has increased interest in the use of three dimensional technologies – with reported use by up to 14% of orthopaedists in the US- despite the fact that scientific evidence has been mixed. The next generation is merging these technologies, taking the best features of both to give the surgeon control of the patient specific TKA process. Sophisticated morphing technology coupled with innovative instrumentation now allows MONITORED real time PSI – affording the surgeon a means to fully understand the knee deformity being addressed, make decisions based on quantitative information that is accurate and easy to assess, and to resect and position parts as planned, confirming position easily (See Figure 1 & Figure 2). Additional ability to perform and monitor balancing is available if desired. From April 2012 to April 2013 sixty-two TKAs in 56 patients underwent TKA using the Exactech GPS system. Twenty-four knees had CR TKA for varus deformity, 5 for valgus deformity; 27 had PS TKA for varus deformity, 5 for valgus deformity. The average AP alignment was 4.0°; the average clinical ROM at the most recent follow-up for CR TKA was 107° vs. 112° for PS TKA which was not significantly different. One knee has been revised to a more constrained insert for CR deficiency. These cases were to validate the integrity of the instruments and software of a new navigation system. In April 2013, personalized instrumentation has been introduced to easily position femoral resection pins through a single, navigated instrument. Pin accuracy and cutting efficiency are easily documented, and proper femoral position in all planes is controlled. No additional imaging is needed, and the surgeon controls all aspects of decision making directly, monitored real-time patient specific TKA. It can easily be integrated for a balanced gap approach to implant positioning. This represents the newest application of three dimensional technologies and continues the field moving toward technologies that allow the surgeon to directly control all aspects of patient specific TKA.
The senior surgeon has performed THA in his practice for over 30 years, and, while performing THA and revision THA utilizing a variety of surgical approaches, has employed and taught the modified Gibson posterolateral approach to the hip joint as his “workhorse” surgical approach for the majority of his career. In following the development of the DAA, he felt that there were subgroups of patients in his practice for whom the DAA, and supine THA, might prove beneficial, and started to introduce this approach into his practice 2 years ago. This retrospective review describes the risks and benefits of choosing to introduce this approach, and outlines a rational way in which surgeons can decide if they should learn and then offer this approach to appropriate patients within their practice. A retrospective study was performed comparing outcomes of patients who underwent THA with the standard posterolateral approach vs. those who underwent THA with the direct anterior approach. Demographics such as age, gender, BMI and medical history were obtained. In addition, operative information and pre- and post-operative Harris Hip Score (HHS) evaluations were collected. Radiographic information and details about complications were also acquired.INTRODUCTION:
METHODS AND MATERIALS:
While clinically successful for decades, CR TKA is persistently compromised by inconsistent PCL function. Problems of mid-flexion instability, incomplete knee flexion, erratic kinematic behavior and posterior instability, not seen with PS devices, raise concerns about the consistency of the technique, and the devices used. Most TKA systems offer at least 2 different geometries of tibial inserts to address this clinical problem. We hypothesize these problems are a result of compromise of PCL anatomy. To avoid compromise to the PCL 3 steps are required: 1) The slope of tibial resection must be less than 5°; 2) the depth of tibial resection must be based off the insertion footprint of the PCL, not the deficiencies of the tibial articular surface; and 3) the tibial insert must be modified to allow intraoperative balancing of the PCL. The CR Slope ™ implants and technique (Exactech) (“Posterior Cruciate Referencing Technique (PCRT)”) reflect this philosophy and have allowed consistent surgical intervention without PCL release and without multiple inserts. We present data identifying, the footprint, and the instrument and technique modifications that allow for predictable identification of the depth and angle of resection. At 2 years post implantation in the first 100 patients implanted, the study group has demonstrated similar operative time, LOS and Oxford knee scores (OKS), while ROM averaged 5° greater, and time to achieved flexion was decreased.Introduction
Results
Total hip arthroplasty (THA) and Total knee arthroplasty (TKA) are successful operations that predictably restore function and provide pain relief for up to 20 years. What happens if they fail in the elderly patient? The purpose of this review was to evaluate pain relief, function and quality of life (QOL) in octogenarian patients undergoing revision total joint arthroplasty (TJA). We reviewed our surgical database to find all patients who were 80 years or older at the time of revision surgery. From 1993 through 2008, there were 61 revision THAs (52 patients) and 33 revision TKAs (29 patients). This represented 3% and 8% respectively of all arthroplasties and revision arthroplasties done during the same period. Outcomes evaluated include Harris Hip Scores (HHS), Knee Society Scores (KSS), complications, and QOL. The average follow-up for revision THA patients with completed Harris Hip Evaluations was 27 months (range: 3 – 126 months). HHS improved from 47 pre-operatively to 74 at most recent follow-up. Pain Scores improved from 20 to 39, Function Scores from 11 to 16, Activities Scores from 9 to 10, Deformity Scores from 2 to 4 and ROM Scores from 5 to 6. Complications occurred in 34% of these cases. The average follow-up for revision TKA patients with completed Knee Society Evaluations was 38 months (range: 11 – 98 months). KSS improved from 48 preoperatively to 84 at the most recent follow-up. Pain Scores improved from 22 to 43 and Function Scores from 20 to 34. Complications occurred in 47% of these cases. Total HHS and KSS greatly improved postoperatively with the most notable improvement in the Pain category. Complications were common, although most were considered minor. More severe complications occurred when revisions of all components were needed, more likely in TKA than THA. With careful selection, patient education and preoperative planning, revision TJA can be done safely and provide benefit for the elderly patient.
One of these total hip arthroplasties has been revised for incomplete femoral fixation leading to a 96% survival rate at an average follow-up of 22 months (range: 2 – 74 months). The average Harris Hip Score for these patients at the most recent follow-up was 87.
