Economic Studies for Lower Extremity Joint Arthroplasty: An Example-Based Review.

As healthcare costs in the United States continue to rise, understanding the various economic studies and what constitutes them will become increasingly important for orthopaedic surgeons. In this review, we discuss the three major types of economics studies and provide examples of each. Cost-effective analyses are the gold standard for economic analyses and allow for the direct comparison of monetary costs and patient-centered outcomes. Cost-benefit analyses are similar to cost-effective analyses but compare both costs and benefits in monetary terms. Cost minimization analyses are the most common type of economic analysis, and they simply compare costs between two experimental groups. Also, we discuss the different types of costs, i.e., healthcare system costs and reimbursements, and how the use of each type affects the conclusions that researchers can draw.

The Impact of Glucagon-Like Peptide-1 Agonists on Hip and Knee Arthroplasty and Perioperative Considerations.

Glucagon-Like Peptide agonists have traditionally been used for glycemic control in diabetic patients. However, there has been a dramatic rise in their utilization for weight loss management. As such, arthroplasty surgeons will encounter an increasing number of patients on these medications, and therefore it is important to understand the implications of their use in the perioperative period. This review will describe the pharmacological actions of these medications as well as the impact on hip and knee arthroplasty patients, and considerations for perioperative management. Because of the rapid adaption and utilization of these drugs, the science is evolving at a fast pace. More and longer-term studies are needed to truly understand the impact of these medications on total joint arthroplasty utilization and in management of these patients in the perioperative period.

Technology Review: CT Scan-Guided, 3-Dimensional, Robotic-Arm Assisted Lower Extremity Arthroplasty.

Robotic-arm assisted lower extremity arthroplasty using computed tomography scan (CT)-based 3-dimensional (3D) modeling operative technologies has increasingly become mainstream over the past decade with over 550,000 procedures performed between first use in 2006 and November 2021. Studies have demonstrated multiple advantages with these technologies, such as decreased postoperative pain and subsequent decreased narcotic usage, decreased lengths of stay, less complications, reduced damage to soft tissues, decreased readmissions, as well as economic advantages in the form of meaningful cost savings for payors. The purpose of this report was to clearly and concisely summarize the good-to-high methodology peer-reviewed, published literature regarding CT scan-based, 3-dimensional robotically-assisted unicompartmental knee arthroplasty, total knee arthroplasty, and total hip arthroplasty stratified by: (1) prospective randomized studies; (2) database comparison studies; (3) national registry studies; (4) health utility studies; (5) comparison studies; and (6) basic science studies. A literature search was conducted and, after applying inclusion criteria, each study was graded based on the modified Coleman methodology score ("excellent" 85-100, "good" 70-84, "fair" 55-69, "poor" <54 points). A total of 63 of 63 good-to-excellent methodology score reports were positive for this technology, including 11 that demonstrated decreased pain and/or opioid use when compared to traditional arthroplasty techniques. The summary results of these high-quality, peer-reviewed published studies demonstrated multiple advantages of this CT scan-based robotic-arm assisted platform for lower extremity arthroplasty.

Normothermia in Arthroplasty.

BACKGROUND: Since the initial design of surgical theatres, the thermal environment of the operating suite itself has been an area of concern and robust discussion. In the 1950s, correspondence in the British Medical Journal discussed the most suitable design for a surgeon's cap to prevent sweat from dripping onto the surgical field. These deliberations stimulated questions about the effects of sweat-provoking environments on the efficiency of the surgical team, not to mention the effects on the patient. Although these benefits translate to implant-based orthopedic surgery, they remain poorly understood and, at times, ignored. METHODS: A review and synthesis of the body of literature on the topic of maintenance of normothermia was performed. RESULTS: Maintenance of normothermia in orthopedic surgery has been proven to have broad implications from bench top to bedside. Normothermia has been shown to impact everything from nitrogen loss and catabolism after hip fracture surgery to infection rates after elective arthroplasty. CONCLUSION: Given both the physiologic impact this has on patients, as well as a change in the medicolegal environment around this topic, a general understanding of these concepts should be invaluable to all surgeons.

Robotic-Arm Assisted Total Knee Arthroplasty Demonstrated Soft Tissue Protection.

INTRODUCTION: While total knee arthroplasty (TKA) procedures have demonstrated clinical success, occasionally intraoperative complications can occur. Collateral or posterior cruciate ligament injury, instability, extensor mechanism disruption, and tibiofemoral or patellofemoral dislocation are among a few of the intraoperatively driven adverse events prevalently ranked by The Knee Society. Robotic-arm assisted TKA (RATKA) provides a surgeon the ability to three-dimensionally plan a TKA and use intraoperative visual, auditory, and tactile feedback to ensure that only the desired bone cuts are made. The potential benefits of soft tissue protection in these surgeries need to be further evaluated. The purpose of this cadaver study was to assess the a) integrity of various knee soft tissue structures (medial collateral ligament [MCL], lateral collateral ligament [LCL], posterior cruciate ligament [PCL], and the patellar ligament), as well as b) the need for tibial subluxation and patellar eversion during RATKA procedures. MATERIALS AND METHODS: Six cadaver knees were prepared using RATKA by a surgeon with no prior clinical robotic experience. These were compared to seven manually performed cases as a control. The mean Kellgren-Lawrence score was 2.8 (range, 0 to 4) in RATKA and 2.6 (range, 1 to 4) in the manual cohort. The presence of soft tissue damage was assessed by having an experienced surgeon perform a visual evaluation and palpation of the PCL, MCL, LCL, and the patellar ligament after the procedures. In addition, leg pose and retraction were documented during all bone resections. The amount of tibial subluxation and patellar eversion was recorded for each case. RESULTS: For all RATKA-assisted cases, there was no visible evidence of disruption of any of the ligaments. All RATKA cases were left with a bone island on the tibial plateau, which protected the PCL. Tibial subluxation and patella eversion were not required for visualization in any RATKA cases. In two of the seven MTKA cases, there was slight disruption noted of the PCL, although this did not lead to any apparent change in the functional integrity of the ligament. All MTKA cases required tibial subluxation and patellar revision to achieve optimal visualization. DISCUSSION: Several aspects of soft tissue protection were noted during the study. During bone resections, the tibia in RATKA procedures did not require subluxation, which may reduce ligament stretching or decrease complication rates. Potential patient benefits for short-term recovery and decreased morbidity to reduce operative complications should be studied in a clinical setting. Since RATKA uses a stereotactic boundary to constrain the sawblade, which is generated based on the implant size, shape, and plan, and does not have the ability to track the patient's soft tissue structures, standard retraction techniques during cutting are recommended. Therefore, the retractor placement and potential for soft tissue protection needs to be further investigated. RATKA has the potential to increase soft tissue protection when compared to manual TKA.

Robotics in Arthroplasty: A Comprehensive Review.

Robotic-assisted orthopedic surgery has been available clinically in some form for over 2 decades, claiming to improve total joint arthroplasty by enhancing the surgeon's ability to reproduce alignment and therefore better restore normal kinematics. Various current systems include a robotic arm, robotic-guided cutting jigs, and robotic milling systems with a diversity of different navigation strategies using active, semiactive, or passive control systems. Semiactive systems have become dominant, providing a haptic window through which the surgeon is able to consistently prepare an arthroplasty based on preoperative planning. A review of previous designs and clinical studies demonstrate that these robotic systems decrease variability and increase precision, primarily focusing on component positioning and alignment. Some early clinical results indicate decreased revision rates and improved patient satisfaction with robotic-assisted arthroplasty. The future design objectives include precise planning and even further improved consistent intraoperative execution. Despite this cautious optimism, many still wonder whether robotics will ultimately increase cost and operative time without objectively improving outcomes. Over the long term, every industry that has seen robotic technology be introduced, ultimately has shown an increase in production capacity, improved accuracy and precision, and lower cost. A new generation of robotic systems is now being introduced into the arthroplasty arena, and early results with unicompartmental knee arthroplasty and total hip arthroplasty have demonstrated improved accuracy of placement, improved satisfaction, and reduced complications. Further studies are needed to confirm the cost effectiveness of these technologies.

A Patient Blood Management Program in Prosthetic Joint Arthroplasty Decreases Blood Use and Improves Outcomes.

The objective of this study was to determine if a Patient Blood Management (PBM) program implemented for patients undergoing THA or TKA would result in a decrease in the percentage of patients transfused PRBCs and improve outcomes. Decision support, a key driver for this program, was built into the electronic medical record. This retrospective cohort study included 12,590 patients and demonstrated a 44% decrease in the percentage of patients transfused. This was associated with a significant reduction in complications, 30 day readmissions and HLOS. A PBM program for patients undergoing prosthetic joint arthroplasty for primary and revision total hip and knee arthroplasty results in fewer transfusions and is associated with improved outcomes.

Bilateral Symmetrical Comparison of Femoral and Tibial Anatomic Features.

BACKGROUND: Variability in morphologic features of the human lower extremity within and across populations has been reported, but limb asymmetry within individuals is often overlooked. For example, in 19 studies of version of the lower extremity in the literature, 6 document asymmetry in the population, but none of these reports document asymmetry in an individual. The aim of this study was to identify the (a)symmetry and quantify variability in the tibiae and femora of matched pairs of limbs. More specifically, using a computed tomography scan database tool, we (1) identified (a)symmetry between paired left and right legs for angulation, version, and alignment features and (2) calculated the percentage of paired limbs with >1° of (a)symmetry for each evaluated parameter. METHODS: Computerized axial tomographic scans (<1.0 mm slices) from bilateral lower limbs of 361 skeletally mature subjects without bone pathology were prospectively acquired. Bones were segmented and morphologic features were measured. RESULTS: Angular features are symmetric left to right, but rotational features are not, with 7° of mean asymmetry in femoral anteversion (range: 0°-23°) and 3° of asymmetry in tibial version (range: 0°-8°). CONCLUSIONS: This study disproves the hypothesis that human limbs are absolutely symmetric, confirming instead that there is asymmetry in version between left and right paired limbs. Surgeons strive for symmetry in lower extremity reconstruction, and they often compare side to side in outcome studies, believing that normal limbs are absolutely symmetric when this is not necessarily true. These assumptions concerning lower extremity symmetry need to be reassessed.

Early postoperative complications after total hip arthroplasty: current strategies for prevention and treatment.

Total hip arthroplasty is a highly successful treatment for end-stage arthritis that substantially improves patients' symptoms and function. Unfortunately, complications in the early postoperative period are inevitable, even in procedures performed by experienced surgeons using careful surgical techniques. Current strategies to prevent and effectively manage the most common early complications after total hip arthroplasty, including periprosthetic joint infection, instability, leg-length inequality, and periprosthetic femoral fracture, are discussed.

Quantitative, Comparative Assessment of Gait Between Single-Radius and Multi-Radius Total Knee Arthroplasty Designs.

Gait of single-radius (SR, n=16) and multi-radius (MR, n=16) posterior stabilized total knee arthroplasties was compared, along with controls (n=16), pre-op and 1 year post-op. Computer navigation and standard order sets controlled confounding variables. Post-operatively, SR knees did not differ from controls while MR knees continued to differ in important knee kinetic and kinematic properties. MR knees remained more extended (P=0.019) and had decreased power absorption (P=0.0001) during weight acceptance compared to the SR knees. Both surgical groups had similar KSS for Knee Scores (P=0.22) and Function Scores (P=0.58). The significant biomechanical differences are likely influenced by patella-femoral moment arm geometry and changing ligament laxity throughout the active range of motion.

Makoplasty and the accuracy and efficacy of robotic-assisted arthroplasty.

In comparison with standard surgical techniques robotic-assisted surgery has the advantages of increased surgical accuracy, reproducibility, optimization of component position, and improved patient outcomes in unicompartmental knee arthroplasty (UKA) and total hip arthoplasty (THA) procedures. The MAKO Tactile Guidance System (TGS; MAKO Surgical Corp, Fort Lauderdale, FL) facilitates robotic-assisted arthroplasty procedures currently implemented in many operating rooms. The benefits of this technology are evident, but have not been shown to improve patient outcomes and justify the added financial burden imposed. Further research is needed to determine if this technological advancement will translate into improvements in longevity and clinical outcomes.

Understanding economic analysis and cost-effectiveness of CT scan-guided, 3-dimensional, robotic-arm assisted lower extremity arthroplasty: a systematic review.

Aim: The overall goal of this review was to examine the cost-utility of robotic-arm assisted surgery versus manual surgery. Methods: We performed a systematic review of all health economic studies that compared CT-based robotic-arm assisted unicompartmental knee arthroplasty, total knee arthroplasty and total hip arthroplasty with manual techniques. The papers selected focused on various cost-utility measures. In addition, where appropriate, secondary aims encompassed various clinical outcomes (e.g., readmissions, discharges to subacute care, etc.). Only articles directly comparing CT-based robotic-arm assisted joint arthroplasty with manual joint arthroplasty were included, for a resulting total of 21 reports. Results: Almost all twenty-one studies demonstrated a positive effect of CT scan-guided robotic-assisted joint arthroplasty on health economic outcomes. For studies reporting on 90-day episodes of costs, 10 out of 12 found lower costs in the robotic-arm assisted groups. Conclusion: Robotic-arm assisted joint arthroplasty patients had shorter lengths of stay and cost savings based on their 90-day episodes of care, among other metrics. Payors would likely benefit from encouraging the use of this CT-based robotic technology.

Valgus bracing affords short-term treatment solution across walking and sit-to-stand activities.

Since activities of daily living do not exist in isolation this prospective study examined biomechanical function during level walking and sit-to-stand activities over two months of brace use by subjects with varying grades of knee osteoarthritis. Kinematic and kinetic data were collected using infrared cameras and force platforms; clinical scores compared perceived and measured functional effects. There was no significant change in pain for any grades of OA but activity levels were significantly higher at one month in the moderate OA grades and at two months for the low OA grades. Mechanical constraints and changes in movement strategies were consistent across tasks and OA grade. This study provides valuable data for further studies aimed at refining the use and optimization of valgus bracing efficacy.

Differences between midvastus and subvastus TKA surgical approaches in the tasks of sitting and standing.

The mini-midvastus (MV) approach to total knee arthroplasty (TKA) minimizes damage to the extensor mechanism; however, the mini-subvastus (SV) approach is designed to avoid such damage. Quadriceps weakness following TKA can have a significant impact on the activities of daily living, particularly stand-to-sit down (STSD) and sit-to-stand up (STSU) activities. Fifty-three subjects diagnosed with primary osteoarthritis and scheduled to undergo TKA were randomized to receive an MV or SV surgical approach and were given identical postoperative orders. Compared with age-matched controls, the SV group had a quicker return of normal peak knee extension moment during STSU, whereas the MV group had a quicker return of normal movement patterns in hip, knee, and ankle parameters during STSD yet represented the higher functioning subjects as more MV subjects had difficulty completing the task as instructed. Considering both movements are required for daily living, neither surgical group was found to have a significant advantage over the other in functional outcome through 6 months post-TKA.

Role of total knee arthroplasty approaches in gait recovery through 6 months.

Four major approaches to total knee arthroplasty (TKA) exist: standard parapatellar, subvastus, midvastus, and mini-parapatellar. Research has shown that there may be some benefit to patients when minimally invasive approaches are employed. However, research has not shown whether the minimally invasive approaches are beneficial for restoring patients' gait when compared against those of healthy age-matched subjects. This study has compared the effect of the four surgical approaches using computer navigation on recovery of gait at 2, 4, and 6 months. Although some statistically significant differences exist among surgical approaches at specific points of the gait cycle, results demonstrate that no approach is superior to another in restoring patients' gait across the entire gait cycle.

Differences between standard and minimally invasive parapatellar surgical approaches for total knee arthroplasty in the tasks of sitting and standing.

Minimally invasive total knee arthroplasty (TKA) aims to enhance functional recovery and minimize trauma to the knee extensor mechanism through quadriceps sparing techniques. Few have studied the effect of TKA surgical approach on activities of daily living. Stand-to-sit-down (STSD) and sit-to-stand-up (STSU) activities are challenging for patients in constrained scenarios where upper body support is limited. In this study, 60 subjects diagnosed with primary osteoarthritis undergoing TKA were randomized to receive the standard parapatellar (SP) or mini-parapatellar (MP) surgical approach performed using computer navigation. All received identical postoperative orders, hospitalization, and physical therapy. Before surgery and at 2, 4, and 6 months postoperatively, the STSD and STSU kinetics and kinematics showed differences for both groups in comparison with controls, but the two were essentially indistinguishable throughout all time points.

Preoperative Activity Level an Indicator of Postoperative Functional Outcomes with a Contemporary Revision Total Knee System.

As the population requiring revision total knee arthroplasty (rTKA) grows, varying preoperative conditions may need to be considered when attempting to predict postoperative outcomes. Considering preoperative activity levels may help manage the expectations of patients. The purpose of this study was to analyze the outcomes of low- and high-activity subgroups of patients receiving a contemporary rTKA. One hundred and eighty-one rTKA patients enrolled in a prospective multicenter study were evaluated over a minimum follow-up of 2 years postoperatively. Patients were divided into two groups based on the preoperative activity level using the Lower Extremity Activity Scale. Patients scoring between 1 and 7 were classified as "Low Activity" (LA; N = 105) and patients scoring 8 to 18 were classified as "High Activity" (HA; N = 76). Clinical outcomes were evaluated, with an additional quality-of-life analysis completed utilizing SF-6D (6-dimension short form) scores obtained through a method described by Brazier et al and analyzed for effect size. There were no significant differences in age or body mass index between the groups. Postoperative improvement in both groups were similar in the Knee Society score (KSS), but the LA group showed larger increases in the KSS functional assessment at 6 months (16.2) and 2 years (34.8). There was a statistically significant effect (0.96, p = 0.0006) seen in the LA group at 1 year, in conjunction with a higher SF-6D outcome. The current study population displayed significant improvement in functional patient outcomes following rTKA regardless of preoperative activity level and function. Patients with lower preoperative activity levels demonstrated greater cumulative functional and quality-of-life improvements. This suggests that a lower preoperative activity level may be related to a poorly functioning knee and that rTKA has the potential to improve overall activity levels and function. Low preoperative function should not disqualify patients for rTKA.

Improving initial acetabular component stability in revision total hip arthroplasty calcium phosphate cement vs reverse reamed cancellous allograft.

A reproducible retroacetabular defect was created bilaterally in 9 cadaver pelves. The defects were filled with either an injectable, bioresorbable, calcium phosphate cement, or reverse-reamed cancellous allograft. An uncemented acetabular shell was impacted, followed by the placement of an appropriate liner. The pelves were then sectioned, and each half was loaded in a material testing machine to simulate walking on the construct over a several week period. The cement-filled defects lasted a greater number of cycles before failure and had greater cup stability and stiffness. The use of resorbable bone void filler for retroacetabular defects shows promise in this biomechanical analysis. Long-term clinical follow-up is warranted to track osseointegration of the implant and restoration of bone stock between this and other clinically accepted surgical techniques.

Management of Metastatic Disease in Long Bones.

LEVEL OF EVIDENCE: Therapeutic Level V. See Instructions for Authors for a complete description of levels of evidence.

Management of Primary Aggressive Tumors of the Knee.

Primary bone sarcomas and aggressive benign bone tumors are relatively rare. It is essential to recognize features that are concerning for these aggressive tumors based on a patient's history, physical exam, and radiographs. Physicians and other health care providers should have a high suspicion for these tumors and promptly refer these patients to orthopaedic oncologists. A multidisciplinary, team-based approach is required to obtain an accurate diagnosis and provide comprehensive care. This review discussed the appropriate work-up, biopsy principles, relevant peri-operative medical management, and surgical treatment options for patients with aggressive primary bone tumors around the knee. Primary bone sarcomas (osteosarcoma and chondrosarcoma) and aggressive benign bone tumors (giant cell tumor, chondroblastoma, and chondromyxoid fibroma) that have a predilection to the distal femur and proximal tibia are the focus of this review.