THA Anterior Approach Protocol: Your Guide

The Direct Anterior Approach to total hip arthroplasty (THA) is a minimally invasive surgical technique and Smith & Nephew offers specialized surgical instruments which enhance the precision required for the procedure. This tha anterior approach protocol prioritizes muscle preservation, potentially leading to quicker recovery times, and it necessitates adherence to specific guidelines for patient selection and surgical execution. The American Academy of Orthopaedic Surgeons (AAOS) provides comprehensive resources on THA, including best practice guidelines that support informed decision-making in adopting the anterior approach, where appropriate patient selection is a key component.

Understanding the Direct Anterior Approach for Total Hip Arthroplasty

Total Hip Arthroplasty (THA), commonly known as hip replacement, stands as a cornerstone in modern orthopedic surgery. It offers a pathway to renewed mobility and a life free from debilitating hip pain.

At its core, THA involves the surgical removal of a damaged hip joint. It is then replaced with an artificial joint or prosthesis.

The Core Aim: Pain Relief and Enhanced Functionality

The primary goal of THA is twofold: alleviating persistent hip pain and restoring optimal hip function. This intervention becomes necessary when conservative treatments. Such as physical therapy and medication, prove ineffective in managing conditions like osteoarthritis, rheumatoid arthritis, or traumatic injuries.

A successful THA empowers individuals to resume daily activities. These activities were previously hindered by pain and limited range of motion.

A Historical Perspective

The journey of hip replacement surgery is marked by continuous innovation. The initial attempts in the late 19th century paved the way for the groundbreaking work of Sir John Charnley in the 1960s.

Charnley's low-friction arthroplasty design, featuring a metal femoral stem and a polyethylene acetabular cup, revolutionized the field and laid the foundation for modern THA techniques.

Advancements in materials, surgical techniques, and implant designs have significantly improved the longevity and success rates of THA over the decades.

The Emergence of the Direct Anterior Approach (DAA)

Among the various surgical approaches to THA, the Direct Anterior Approach (DAA) has gained considerable traction in recent years. DAA distinguishes itself as a muscle-sparing technique. This is a key characteristic.

Unlike traditional approaches that involve cutting or detaching muscles, DAA utilizes an intermuscular and internervous plane to access the hip joint. This approach minimizes disruption to the surrounding soft tissues.

Rationale for Choosing DAA

The DAA offers several potential advantages that have contributed to its increasing popularity among surgeons and patients alike. One of the key benefits is the potential for faster recovery.

Due to the reduced muscle damage, patients undergoing DAA THA may experience less post-operative pain, quicker rehabilitation, and a shorter hospital stay.

Moreover, DAA is associated with a lower risk of hip dislocation compared to traditional posterior approaches. This is attributed to the preservation of the posterior hip capsule and muscles.

Understanding the Direct Anterior Approach for Total Hip Arthroplasty Total Hip Arthroplasty (THA), commonly known as hip replacement, stands as a cornerstone in modern orthopedic surgery. It offers a pathway to renewed mobility and a life free from debilitating hip pain.

At its core, THA involves the surgical removal of a damaged hip joint. It is...

The Surgical Team: Roles and Responsibilities in DAA THA

The success of a Direct Anterior Approach (DAA) Total Hip Arthroplasty hinges not only on the surgeon's skill but also on the coordinated efforts of a highly specialized surgical team. Each member brings unique expertise to ensure patient safety, procedural accuracy, and optimal outcomes.

Let's explore the distinct roles and responsibilities within this collaborative environment.

The Orthopedic Surgeon: Orchestrating the Procedure

The orthopedic surgeon is the central figure, bearing ultimate responsibility for the successful execution of the DAA THA. Their role encompasses far more than just the surgical procedure itself.

It begins with a thorough pre-operative assessment, including a comprehensive medical history, physical examination, and review of imaging studies. This careful evaluation is critical for determining patient suitability for the DAA and tailoring the surgical plan to their specific anatomy and needs.

During the operation, the surgeon's expertise in the DAA technique is paramount. They must precisely navigate the anatomical structures, ensuring meticulous muscle sparing and accurate implant placement.

Specialized training in THA and, specifically, the DAA is essential. This includes mastering the nuances of the surgical approach, understanding the biomechanics of the hip joint, and being proficient in the use of specialized instruments and equipment.

Post-operatively, the surgeon continues to oversee the patient's recovery, monitoring their progress, managing pain, and addressing any complications that may arise.

Other Key Personnel: A Symphony of Expertise

While the surgeon leads the operation, the contributions of other team members are indispensable. Each plays a crucial role in creating a safe and efficient surgical environment.

Surgical Assistants: The Surgeon's Right Hand

Surgical assistants work closely with the orthopedic surgeon, providing essential support throughout the procedure.

Their responsibilities include assisting with retraction to maintain optimal exposure of the surgical site, handling instruments, and ensuring a smooth workflow.

Anesthesiologists: Guardians of Patient Well-being

The anesthesiologist is responsible for managing the patient's anesthesia, ensuring their comfort and safety throughout the surgery.

They continuously monitor vital signs, administer medications as needed, and address any anesthetic complications that may arise.

Operating Room Nurses: Orchestrating the Surgical Environment

Operating room (OR) nurses are vital in preparing the OR, ensuring that all instruments and equipment are sterile and readily available.

They assist the surgical team during the procedure, anticipating their needs and maintaining a sterile environment to minimize the risk of infection.

Physical Therapists: Guiding Post-operative Rehabilitation

Physical therapists are crucial in the pre- and post-operative phases. Pre-operatively, they assess the patient's functional status and educate them about the rehabilitation process.

Post-operatively, they design and implement individualized rehabilitation programs to help patients regain strength, range of motion, and function.

Early and consistent physical therapy is essential for optimal recovery after DAA THA.

Occupational Therapists: Restoring Independence in Daily Living

Occupational therapists (OTs) focus on helping patients regain independence in performing activities of daily living (ADLs).

This includes tasks such as dressing, bathing, cooking, and homemaking. They may recommend adaptive equipment or strategies to make these activities easier and safer.

Physician Assistants (PAs): Extending the Surgeon's Reach

Physician Assistants (PAs) work under the supervision of the orthopedic surgeon to provide comprehensive patient care.

Their responsibilities may include assisting in surgery, conducting pre-operative and post-operative patient evaluations, ordering and interpreting diagnostic tests, and prescribing medications. PAs contribute to continuity of care for patients throughout the surgical journey.

In conclusion, DAA THA requires a team-based approach, with each member contributing their unique skills and expertise. Effective communication and collaboration are essential for ensuring patient safety and achieving optimal outcomes.

Surgical Approaches to THA: A Comparison

Understanding the Direct Anterior Approach for Total Hip Arthroplasty Total Hip Arthroplasty (THA), commonly known as hip replacement, stands as a cornerstone in modern orthopedic surgery. It offers a pathway to renewed mobility and a life free from debilitating hip pain. At its core, THA involves the surgical removal of a damaged hip joint. It is.... Now, let's dissect the nuances of various surgical approaches employed in THA, with particular attention to the Direct Anterior Approach and its standing amidst the broader landscape of hip replacement techniques.

Deep Dive into the Direct Anterior Approach (DAA)

The Direct Anterior Approach (DAA) to THA is characterized by its muscle-sparing nature. This means the surgeon accesses the hip joint through an interval between muscles, rather than cutting through them.

Specifically, the incision is made on the front of the hip, allowing access to the joint without detaching muscles from the femur or pelvis. This approach often leads to reduced post-operative pain and a potentially faster recovery.

The DAA involves meticulous dissection and precise surgical technique. It requires a thorough understanding of the anatomical structures in the anterior hip region. The surgeon carefully retracts muscles to expose the hip joint capsule, which is then incised to access the femoral head and acetabulum.

Key advantages often attributed to DAA include:

• Reduced risk of hip dislocation.
• Potentially faster rehabilitation.
• Smaller incision (in some cases).

Alternative Approaches: Antero-Lateral and MIS

The Antero-Lateral Approach

The antero-lateral approach is another common surgical technique for THA. This approach involves an incision on the side of the hip.

Unlike the DAA, the antero-lateral approach may require the release of some muscles to gain adequate exposure of the hip joint. This can potentially lead to a longer recovery period compared to DAA in some patients.

DAA and Minimally Invasive Surgery (MIS)

The Direct Anterior Approach is a type of Minimally Invasive Surgery (MIS). MIS techniques aim to minimize tissue trauma during surgery.

DAA achieves this by utilizing a muscle-sparing approach, which reduces the need for extensive muscle cutting and retraction. The goal is to minimize post-operative pain, speed up recovery, and improve functional outcomes.

While DAA is a MIS technique, not all MIS THA procedures utilize the direct anterior approach. Other MIS approaches may involve smaller incisions but still require some degree of muscle release or detachment.

Therefore, it's crucial to distinguish between MIS as a broad category and DAA as a specific technique within that category. The suitability of each approach depends on various factors, including the patient's anatomy, surgeon's experience, and specific goals of the surgery.

Tools of the Trade: Surgical Instruments and Equipment for DAA THA

The success of a Direct Anterior Approach (DAA) Total Hip Arthroplasty (THA) hinges not only on surgical skill but also on the meticulous application of specialized instruments and equipment. Understanding these tools provides insight into the precision and care that define the DAA technique. Let's explore the key elements that empower surgeons to perform this muscle-sparing procedure with optimal outcomes.

The Specialized Surgical Table: Optimizing Access and Precision

Patient positioning is paramount in DAA THA, and specialized surgical tables, such as the Hana table, play a crucial role. These tables allow for controlled leg positioning. They facilitate hip extension, adduction, and external rotation, providing the surgeon with optimal access to the anterior hip capsule.

The Hana table, in particular, employs a unique design with adjustable leg supports and a perineal post. This allows for controlled traction and rotation of the femur. Surgeons gain enhanced visualization and maneuverability during component placement. By optimizing access, these tables can contribute to reduced tissue trauma and improved implant alignment.

Imaging and Instrumentation: Guiding Accuracy and Efficiency

Intraoperative Fluoroscopy (C-arm)

Real-time imaging is indispensable in DAA THA. Fluoroscopy, often using a C-arm, provides surgeons with immediate visual feedback during critical steps. It aids in acetabular cup placement, femoral stem insertion, and assessment of leg length and offset.

This real-time X-ray guidance minimizes the need for extensive soft tissue dissection. It enhances the accuracy of component positioning. Precise placement translates to improved joint biomechanics and reduced risk of postoperative complications.

Specialized Surgical Instruments

The DAA requires a specific set of surgical instruments designed for the anterior approach. These include specialized retractors that gently separate muscle fibers. They provide access to the hip joint without extensive cutting.

Examples include the Weinberg retractor and Heuter retractor. These retractors are designed to minimize muscle trauma and optimize visualization. Furthermore, specialized broaches and rasps are used for femoral canal preparation and acetabular reaming, respectively.

Implant Components and Navigation: Tailoring Solutions for Optimal Outcomes

Implant Components: A Range of Options

THA involves replacing the damaged hip joint with artificial components. These components typically include a femoral stem, an acetabular cup, and a femoral head. The selection of these components is a critical decision, influenced by factors such as patient age, bone quality, activity level, and surgeon preference.

• Femoral Stem: Available in various designs (cemented, uncemented, hybrid). They are designed to provide stable fixation within the femoral canal.
• Acetabular Cup: Typically made of titanium or a titanium alloy. It is often coated with a porous material to promote bone ingrowth.
• Femoral Head: Typically made of ceramic or metal. It articulates with the acetabular cup to restore smooth hip joint motion.

Navigation Systems: Enhancing Precision and Accuracy

Computer-assisted navigation systems are increasingly used in DAA THA. These systems employ sensors and software to provide real-time feedback on implant position and alignment. Navigation can improve the accuracy of cup placement, leg length restoration, and offset reconstruction.

While not universally adopted, navigation systems offer the potential for enhanced precision. Some studies suggest improved long-term outcomes and reduced risk of dislocation. Ultimately, the decision to use navigation depends on surgeon experience and institutional resources.

Anatomical Considerations: Navigating the Hip Joint During DAA THA

Tools of the Trade: Surgical Instruments and Equipment for DAA THA

The success of a Direct Anterior Approach (DAA) Total Hip Arthroplasty (THA) hinges not only on surgical skill but also on the meticulous application of specialized instruments and equipment. Achieving optimal outcomes with DAA THA also demands a profound understanding of the surgical landscape—the intricate anatomy of the hip joint and surrounding structures.

Understanding Hip Anatomy: A Foundation for Surgical Precision

A successful DAA THA begins with a comprehensive understanding of the hip's intrinsic anatomy. This knowledge is the bedrock upon which surgical decisions are made, ensuring both precision and safety.

The hip joint, a ball-and-socket articulation, is formed by the femoral head fitting into the acetabulum of the pelvis. The stability of this joint is maintained by strong ligaments, including the iliofemoral, pubofemoral, and ischiofemoral ligaments.

Cartilage, a smooth, resilient tissue, lines the articulating surfaces of the femur and acetabulum, facilitating frictionless movement. In conditions like osteoarthritis, this cartilage deteriorates, leading to pain and limited mobility—often necessitating THA.

Biomechanics of the Hip Joint: Relating Anatomy to Function

The hip joint is a marvel of biomechanical engineering, designed to withstand significant loads while providing a wide range of motion. During walking, the hip joint bears several times the body's weight.

Understanding these biomechanics is critical in THA to ensure proper implant selection and placement, restoring natural joint function. The goal of THA is not only to relieve pain but also to replicate the hip's natural biomechanics.

Muscles, Nerves, and Vessels: Navigating the Surgical Landscape

The DAA to THA requires careful navigation around vital anatomical structures. The surrounding muscles, nerves, and blood vessels must be meticulously protected to prevent complications.

The Iliopsoas Muscle: Splitting vs. Retraction

The iliopsoas muscle, a powerful hip flexor, lies directly posterior to the anterior hip capsule. During DAA, surgeons may choose to either split or retract this muscle.

Splitting the iliopsoas can provide excellent exposure but carries a risk of muscle weakness postoperatively. Retraction, on the other hand, preserves muscle integrity but may limit surgical access.

The Tensor Fasciae Latae (TFL) Muscle: Guiding the Approach

The tensor fasciae latae (TFL) muscle, located laterally, serves as an anatomical landmark during the DAA. The surgical incision is typically made between the TFL and the sartorius muscle.

Understanding the TFL's position is vital for a muscle-sparing approach, minimizing tissue trauma and promoting faster recovery.

Nerve Protection: The Femoral and Sciatic Nerves

Protecting the femoral and sciatic nerves is paramount during DAA THA. The femoral nerve lies anterior to the hip joint, while the sciatic nerve is located posteriorly.

Careful dissection and retraction techniques are essential to avoid nerve injury, which can lead to significant postoperative morbidity. Surgeons must have a thorough understanding of the nerve pathways and variations.

Vascular Considerations: The Femoral Artery and Vein

The femoral artery and vein are major blood vessels located close to the anterior hip joint. Injury to these vessels can result in significant bleeding and vascular complications.

Meticulous surgical technique and a detailed understanding of vascular anatomy are crucial to prevent vascular damage during DAA THA. Preoperative planning and intraoperative vigilance are key.

Anatomical Considerations: Navigating the Hip Joint During DAA THA Tools of the Trade: Surgical Instruments and Equipment for DAA THA

The success of a Direct Anterior Approach (DAA) Total Hip Arthroplasty (THA) hinges not only on surgical skill but also on the meticulous application of specialized instruments and equipment. Achieving optimal outcomes, however, also depends on the careful selection of patients with appropriate medical conditions.

Medical Conditions Treated with DAA THA

While the Direct Anterior Approach (DAA) for Total Hip Arthroplasty (THA) offers numerous advantages, its application is most effective when tailored to specific medical conditions affecting the hip joint. Osteoarthritis (OA) stands as the predominant indication for this procedure, but a spectrum of other conditions can also benefit from DAA THA. Careful patient selection is paramount to ensure the best possible outcomes.

Osteoarthritis: The Primary Indication for DAA THA

Osteoarthritis, a degenerative joint disease characterized by the breakdown of cartilage, represents the most common reason for undergoing THA. The progressive loss of cartilage leads to bone-on-bone friction, causing pain, stiffness, and reduced mobility.

DAA THA aims to alleviate these symptoms by replacing the damaged joint surfaces with prosthetic components. The muscle-sparing nature of the DAA can be particularly advantageous for OA patients, potentially leading to a faster recovery and improved functional outcomes compared to traditional approaches.

Beyond Osteoarthritis: Other Relevant Conditions

While osteoarthritis is the leading cause, other medical conditions can also necessitate THA and may be amenable to the DAA technique. These include, but are not limited to:

• Rheumatoid Arthritis: An autoimmune disorder causing chronic inflammation of the joints, leading to cartilage and bone destruction.
• Avascular Necrosis (AVN): Also known as osteonecrosis, this condition occurs when blood supply to the femoral head is disrupted, leading to bone cell death and eventual collapse of the hip joint.
• Hip Dysplasia: A congenital condition characterized by abnormal development of the hip joint, which can lead to early-onset osteoarthritis and instability.

• Post-traumatic Arthritis: Arthritis that develops following a hip injury, such as a fracture or dislocation.

  In each of these cases, DAA THA can offer a viable solution to restore hip function and alleviate pain, provided the patient meets specific criteria. The decision to proceed with DAA THA should be made after a thorough evaluation of the patient's medical history, physical examination, and imaging studies.

Post-Operative Care: Recovery and Rehabilitation After DAA THA

Anatomical Considerations: Navigating the Hip Joint During DAA THA Tools of the Trade: Surgical Instruments and Equipment for DAA THA The success of a Direct Anterior Approach (DAA) Total Hip Arthroplasty (THA) hinges not only on surgical skill but also on the meticulous application of specialized instruments and equipment. Achieving optimal outcomes, however, extends far beyond the operating room and is significantly influenced by the quality of post-operative care and rehabilitation. This crucial phase focuses on facilitating early mobilization, managing pain, and guiding patients through a structured physical therapy program to restore function and independence.

Early Mobilization: The Cornerstone of Recovery

Early mobilization is a fundamental principle in the post-operative care of DAA THA patients. Protocols typically emphasize getting patients out of bed and moving as soon as safely possible, often within hours of the surgery. This early activity is designed to mitigate the risks associated with prolonged bed rest, such as blood clots, pneumonia, and muscle weakness.

This doesn't mean immediately resuming full activity. Instead, it involves a carefully graded progression of movement under the guidance of physical therapists and nursing staff.

The benefits of early mobilization extend beyond preventing complications. It promotes improved circulation, reduces swelling, and helps to maintain muscle strength. It also contributes to improved patient morale and a faster return to normal daily activities.

Weight-Bearing Considerations

Weight-bearing protocols after DAA THA are determined on a case-by-case basis, taking into account factors such as bone quality, implant stability, and the surgeon's preference. Historically, some degree of weight-bearing restriction was common.

However, with advancements in surgical techniques and implant designs, immediate or early weight-bearing as tolerated is increasingly becoming the norm.

Weight-bearing as tolerated allows patients to gradually increase the amount of weight they put on the operated leg, guided by their comfort level and pain. This approach encourages early muscle activation and proprioception (awareness of joint position), which are essential for regaining balance and coordination.

The surgeon will provide specific instructions regarding weight-bearing status, which must be strictly adhered to by the patient to ensure optimal healing and implant stability.

Rehabilitation: Restoring Strength and Function

Physical therapy plays a pivotal role in the rehabilitation process following DAA THA. A structured exercise program is designed to improve strength, range of motion, balance, and functional mobility.

The program typically begins with gentle range-of-motion exercises to prevent stiffness and promote joint lubrication.

As healing progresses, exercises are gradually advanced to include strengthening exercises for the muscles surrounding the hip, such as the gluteals, quadriceps, and hamstrings. Restoring strength in these muscles is crucial for supporting the hip joint and enabling patients to return to their pre-operative activity levels.

Specific Physical Therapy Exercises

Examples of common physical therapy exercises include:

• Ankle Pumps: Help improve circulation in the legs.
• Gluteal Sets: Activate the gluteal muscles.
• Heel Slides: Improve hip and knee flexion.
• Short Arc Quads: Strengthen the quadriceps muscle.
• Standing Hip Abduction: Strengthen the hip abductor muscles.

These exercises are performed under the supervision of a physical therapist, who will ensure proper form and technique to prevent injury.

Pain Management Strategies

Effective pain management is essential for facilitating early mobilization and participation in physical therapy. A multi-modal approach to pain control is typically employed, which may include a combination of:

• Oral Pain Medications: Such as non-steroidal anti-inflammatory drugs (NSAIDs) and opioids.
• Nerve Blocks: To provide localized pain relief.
• Ice Packs: To reduce swelling and inflammation.

Open communication with the medical team about pain levels is crucial. Addressing pain promptly allows patients to engage more effectively in rehabilitation and experience a more comfortable recovery.

Assistive Devices: Aiding Mobility

Assistive devices, such as walkers and canes, are commonly used in the initial stages of recovery to provide support and stability. The type of device used and the duration of use depend on individual needs and progress.

A walker provides maximum support and is typically used in the first few days or weeks after surgery. As strength and balance improve, patients may transition to using a cane.

The use of assistive devices helps to reduce stress on the hip joint, prevent falls, and promote confidence during ambulation. The physical therapist will guide patients on the proper use of these devices and help them wean off them as appropriate.

In conclusion, post-operative care and rehabilitation are integral components of a successful DAA THA. Early mobilization, a tailored physical therapy program, effective pain management, and the judicious use of assistive devices are all crucial for optimizing recovery, restoring function, and enabling patients to return to an active and fulfilling lifestyle.

Potential Complications and Key Considerations in DAA THA

Post-Operative Care: Recovery and Rehabilitation After DAA THA Anatomical Considerations: Navigating the Hip Joint During DAA THA Tools of the Trade: Surgical Instruments and Equipment for DAA THA The success of a Direct Anterior Approach (DAA) Total Hip Arthroplasty (THA) hinges not only on surgical skill but also on the meticulous application of preventive strategies and a thorough understanding of potential complications. While DAA THA offers numerous benefits, a comprehensive approach to risk mitigation is paramount for optimal patient outcomes.

Implant Fixation: Cemented vs. Uncemented

The choice between cemented and uncemented implants is a critical decision point in THA, impacting long-term stability and longevity. Cemented implants rely on polymethylmethacrylate (PMMA) bone cement to secure the prosthesis to the bone. This approach offers immediate fixation and is often preferred in patients with compromised bone quality.

Uncemented implants, on the other hand, feature porous surfaces designed to promote bone ingrowth and biological fixation over time. These implants are generally favored in younger, more active patients with good bone stock. The decision hinges on a careful evaluation of patient-specific factors, including age, bone density, and activity level.

Managing Leg Length Discrepancy

Leg length discrepancy (LLD) is a common concern following THA, potentially leading to gait abnormalities and patient dissatisfaction. Meticulous preoperative planning is crucial, utilizing advanced imaging techniques to accurately assess leg length and hip offset.

Intraoperatively, surgeons employ various techniques to restore equal leg length, including careful implant selection and precise positioning. Real-time assessment with intraoperative imaging can further optimize leg length restoration. Postoperative monitoring and, in rare cases, shoe lifts may be necessary to address persistent discrepancies.

Preventing Hip Dislocation After DAA THA

Hip dislocation remains a potential complication, although the DAA is thought to reduce the risk due to muscle sparing. Patient education regarding hip precautions (avoiding extreme ranges of motion) is essential in the early postoperative period.

The surgeon also plays a critical role in preventing dislocation by ensuring proper implant placement and component orientation. Adherence to established surgical principles and meticulous attention to detail are paramount.

Minimizing the Risk of Surgical Site Infections

Surgical site infections (SSIs) are a devastating complication following THA. Strict adherence to sterile technique is non-negotiable, encompassing preoperative skin preparation, meticulous surgical technique, and appropriate wound management.

Prophylactic antibiotics are administered prior to incision and continued for a short period postoperatively. Ongoing surveillance for signs of infection is crucial, and prompt intervention is necessary if infection is suspected.

Thromboprophylaxis: Preventing DVT and PE

Deep vein thrombosis (DVT) and pulmonary embolism (PE) represent serious thromboembolic complications following THA. Pharmacological thromboprophylaxis (e.g., anticoagulants) is typically initiated pre- or postoperatively, tailored to individual patient risk factors.

Mechanical prophylaxis, such as intermittent pneumatic compression devices, may also be employed. Early mobilization is strongly encouraged to promote venous return and reduce the risk of thromboembolism. Vigilant monitoring for signs and symptoms of DVT and PE is essential for timely intervention.

So, there you have it! Hopefully, this "THA Anterior Approach Protocol: Your Guide" has given you a clearer understanding of what to expect with this procedure. Remember to always discuss your specific situation and concerns with your surgeon – they're the best resource for personalized advice. Here's to a smoother recovery and getting back on your feet!