THA: Definition, Uses, and Clinical Overview

THA Introduction (What it is)

THA stands for total hip arthroplasty, also called total hip replacement.
It is a surgery that replaces damaged parts of the hip joint with artificial components.
It is commonly used for severe hip arthritis and certain hip injuries.
It is performed by orthopedic surgeons in hospitals and surgical centers.

Why THA used (Purpose / benefits)

THA is used to address hip joint damage that causes persistent pain, stiffness, and loss of function. In many hip conditions, the smooth cartilage surfaces that allow the ball-and-socket joint to glide wear down or deform. When that happens, bone and inflamed tissue can create painful friction and limit walking, standing, and everyday activities.

The main purpose of THA is to replace the diseased joint surfaces with prosthetic (implant) surfaces that move more smoothly. In general terms, THA aims to:

• Reduce pain generated by arthritic or damaged joint surfaces
• Improve mobility and function (such as walking distance and ability to perform daily tasks)
• Correct or improve certain mechanical problems (such as joint deformity or leg length differences) when feasible
• Improve overall quality of life when hip symptoms have become limiting despite other care

Outcomes and the degree of improvement vary by clinician and case. THA is a reconstructive procedure, and it is typically considered when symptoms and imaging findings suggest that the hip joint itself is a major source of disability.

Indications (When orthopedic clinicians use it)

Orthopedic clinicians may consider THA in scenarios such as:

• Advanced hip osteoarthritis with significant pain and functional limitation
• Inflammatory arthritis (for example, rheumatoid arthritis) affecting the hip joint
• Osteonecrosis (avascular necrosis) of the femoral head with structural collapse or severe symptoms
• Certain hip fractures in older adults, where replacing the joint may be considered instead of fixation (case-dependent)
• Post-traumatic arthritis after prior hip injury
• Developmental or structural hip disorders (such as dysplasia) leading to end-stage joint degeneration
• Failed prior hip surgery (for example, failed fixation or failed earlier arthroplasty), when a revision or conversion is needed

Indications are individualized and depend on symptoms, exam findings, imaging, overall health, and patient goals.

Contraindications / when it’s NOT ideal

THA is not suitable for everyone. Clinicians may avoid or delay THA, or consider alternatives, in situations such as:

• Active infection anywhere in the body, especially around the hip (absolute concern until treated)
• Suspected or confirmed joint infection (septic arthritis) without adequate treatment
• Severe medical instability where anesthesia and surgery risks outweigh potential benefits
• Poor soft-tissue coverage or significant skin compromise near the surgical site
• Severe neuromuscular or neurologic conditions that markedly increase instability risk (varies by clinician and case)
• Markedly inadequate bone stock that may require complex reconstruction or staged approaches
• Allergies or sensitivities to certain implant metals or materials (material selection may be adjusted; varies by manufacturer)
• Inability to participate in rehabilitation or follow-up (for medical, cognitive, or social reasons), when it meaningfully affects safety and outcomes

Some factors are often considered relative rather than absolute (for example, uncontrolled diabetes, active smoking, severe obesity, or poor nutrition). In these cases, timing and optimization strategies vary by clinician and case.

How it works (Mechanism / physiology)

THA works by replacing the worn or damaged contact surfaces of the hip joint.

Core biomechanical principle

The native hip is a ball-and-socket joint. The “ball” is the femoral head (top of the thigh bone), and the “socket” is the acetabulum (part of the pelvis). In a healthy hip, cartilage covers both surfaces and allows low-friction motion. In arthritis or structural collapse, cartilage and bone shape can deteriorate, increasing friction, inflammation, and pain.

In THA, the damaged femoral head is removed and replaced with a metal stem placed into the femur and a prosthetic head (ball). The acetabulum is prepared and fitted with a cup and a liner (the new socket surface). The goal is to restore smoother motion and more predictable joint mechanics.

Anatomy and tissues involved

THA involves, to varying degrees:

• Bone: femur and acetabulum are prepared to accept implants
• Cartilage and labrum: degenerated surfaces are removed or bypassed by the prosthesis
• Joint capsule and synovium: tissues around the joint that may be thickened or inflamed
• Muscles and tendons: surrounding hip stabilizers are handled and then repaired/managed depending on surgical approach

Onset, duration, and reversibility

The mechanical effect of replacing joint surfaces is immediate, but recovery of strength, gait, and confidence typically takes time. THA is not “reversible” in the way a medication is; once bone is removed and implants are placed, the hip anatomy is permanently changed. If problems occur later, a revision THA (repeat surgery to replace or adjust components) may be possible, depending on the situation.

THA Procedure overview (How it’s applied)

THA is a surgical procedure. Exact techniques vary, but a typical high-level workflow includes:

1. Evaluation and diagnosis – History (pain pattern, function, prior treatments) – Physical exam (range of motion, gait, strength, leg length assessment) – Imaging, most commonly hip X-rays; other imaging may be used in selected cases

2. Preoperative planning and preparation – Review of medical conditions and medications – Planning implant sizing and alignment based on anatomy and imaging – Discussion of risks, expected recovery, and follow-up schedule (informational and consent process)

3. Anesthesia and surgical access – Regional and/or general anesthesia may be used (varies by clinician and case) – An incision is made using a selected approach to reach the hip joint

4. Joint reconstruction (core intervention) – Removal of the damaged femoral head – Preparation of the acetabulum and placement of the cup and liner – Preparation of the femur and placement of the stem and head – Reduction of the hip (ball placed into socket)

5. Immediate checks – Assessment of stability, range of motion, leg length, and component positioning (methods vary) – Wound closure and dressing

6. Early recovery and follow-up – Mobilization and rehabilitation planning – Monitoring for early complications – Scheduled postoperative visits and repeat imaging as needed

This overview is for general education and does not describe a specific surgical plan.

Types / variations

THA is not a single, identical operation for every patient. Common variations include:

• Primary THA vs revision THA
• Primary THA is the first total hip replacement.

• Revision THA replaces or adjusts one or more components from a prior hip replacement, often due to loosening, wear, infection, fracture, or instability.

• Fixation method

• Cementless (press-fit) fixation: components are designed to bond with bone over time.
• Cemented fixation: bone cement helps secure the component immediately.

• Hybrid fixation: a combination (for example, cemented stem with cementless cup), depending on surgeon preference and bone quality.

• Surgical approach

• Common approaches include posterior, lateral (anterolateral), and direct anterior.

• The approach influences which muscles are split or spared and may affect early precautions; selection varies by clinician and case.

• Bearing surface (head/liner material pairing)

• Common pairings include ceramic-on-polyethylene, metal-on-polyethylene, and ceramic-on-ceramic.

• Wear characteristics and noise risk can vary by material and manufacturer.

• Implant features

• Head size: selected to balance stability and wear considerations (case-dependent).
• Dual mobility or constrained liners: may be used in higher-instability-risk situations (not for everyone).

• Standard vs specialized stems/cups: chosen based on anatomy, bone quality, and revision needs.

• Technology assistance

• Some centers use navigation or robotic assistance for component positioning; availability and indications vary.

Pros and cons

Pros:

• Often improves pain driven by end-stage hip joint surface damage
• Can improve walking ability, daily function, and range of motion for many patients
• Addresses mechanical joint problems by replacing both ball and socket surfaces
• Multiple implant designs and material options allow tailoring to anatomy and bone quality
• Can be performed as primary reconstruction or as revision when prior surgery fails (case-dependent)

Cons:

• It is major surgery with anesthesia and perioperative medical risks
• Potential complications include infection, blood clots, dislocation/instability, fracture, nerve or vessel injury, and wound issues
• Implants can wear, loosen, or fail over time, potentially requiring revision surgery
• Some patients experience leg length difference, stiffness, limp, or persistent symptoms despite surgery
• Recovery requires rehabilitation time and follow-up; progress varies widely
• Activity limitations may be recommended by some clinicians to reduce risk of complications (recommendations vary)

Aftercare & longevity

After THA, outcomes are influenced by a mix of surgical factors, patient factors, and rehabilitation factors. While implants are designed for durability, “how long a hip replacement lasts” is not the same for everyone.

Common factors that can affect recovery and longevity include:

• Underlying diagnosis and severity: advanced deformity, prior surgeries, or bone loss can make reconstruction more complex
• Bone quality and healing capacity: influences fixation and long-term stability
• Implant design and materials: wear and performance vary by material and manufacturer
• Surgical positioning and soft-tissue balance: affects stability, function, and comfort
• Rehabilitation participation: gait training, strength recovery, and functional practice are often part of standard postoperative care
• Weight-bearing status and activity level: recommendations differ based on fixation, bone quality, and intraoperative findings
• Comorbidities: conditions such as diabetes, vascular disease, kidney disease, and immune suppression can affect complication risk and healing
• Follow-up and monitoring: periodic assessment helps detect issues such as loosening, wear, or infection signs early

Aftercare protocols (including precautions and therapy intensity) vary by clinician and case. Information from a surgical team is typically tailored to the chosen approach, implants, and intraoperative findings.

Alternatives / comparisons

THA is one option among several for managing hip pain and hip joint disease. Alternatives depend on diagnosis, symptom severity, imaging findings, and patient goals.

Common comparisons include:

• Observation and activity modification
• May be reasonable for mild symptoms or early disease.

• Does not reverse structural arthritis but may help manage symptom triggers.

• Medication-based symptom management

• Options may include anti-inflammatory medications or other pain-modulating medicines (chosen by a clinician).

• These can reduce pain and inflammation for some people but do not replace damaged cartilage.

• Physical therapy and supervised exercise

• Often used to improve strength, mobility, and gait mechanics.

• Can help function and symptom control, especially in earlier stages, but may be less effective when joint surfaces are severely damaged.

• Injections

• Corticosteroid injections may provide temporary symptom relief for some conditions.

• Other injection types may be offered in certain settings; effectiveness and indications vary by clinician and case.

• Hip arthroscopy (minimally invasive hip surgery)

• Often used for labral tears, femoroacetabular impingement (FAI), or selected cartilage problems.

• Generally not a substitute for THA in end-stage arthritis.

• Hip resurfacing

• A bone-preserving alternative in selected patients, often with specific anatomy and activity considerations.

• Not appropriate for many patients, and implant/material considerations differ.

• Hemiarthroplasty

• Replaces only the femoral head (ball) and is commonly discussed in certain hip fractures.
• For arthritis, it typically does not address acetabular cartilage loss as comprehensively as THA.

In practice, clinicians consider the least invasive option that reasonably matches the diagnosis and expected trajectory, while also factoring in functional limitations and imaging.

THA Common questions (FAQ)

Q: What does THA stand for?
THA stands for total hip arthroplasty. It is the medical term for total hip replacement, where both the ball and socket parts of the hip joint are replaced with implants.

Q: Is THA the same as a hip replacement?
In most clinical use, yes. “Hip replacement” is the plain-language term, and THA is the formal term used in orthopedic documentation and research.

Q: How painful is THA and recovery?
Pain experiences vary, but it is common to have postoperative soreness from the incision and tissue healing. Many people report that the deep arthritic joint pain improves as recovery progresses, while surgical pain decreases over time. Pain control approaches vary by clinician and case.

Q: How long do THA implants last?
Longevity depends on patient factors, implant materials, fixation method, activity level, and surgical factors. Some implants function well for many years, while others may need revision earlier due to wear, loosening, infection, or instability. Performance can vary by material and manufacturer.

Q: Is THA considered safe?
THA is a widely performed orthopedic procedure, but it still carries real surgical and medical risks. Safety depends on overall health, surgical complexity, and postoperative factors such as infection prevention and mobility. Your clinician’s team typically reviews individualized risk considerations before surgery.

Q: How long will I be in the hospital after THA?
Length of stay varies by health status, support at home, surgical approach, and local care pathways. Some patients discharge the same day or next day, while others need longer monitoring or short-term rehabilitation.

Q: When can people typically drive or return to work after THA?
Timing varies based on which hip was replaced, strength and reaction time recovery, pain medication use, and job demands. Driving and work decisions are usually tied to functional milestones and safety considerations rather than a single universal timeline.

Q: Will I be able to put weight on the leg right away?
Weight-bearing instructions depend on fixation type, bone quality, and intraoperative findings. Many patients are allowed early weight-bearing, but partial or limited weight-bearing may be used in specific circumstances. This is determined by the surgical team.

Q: What are common risks or complications of THA?
Potential complications include infection, blood clots, dislocation, leg length difference, fracture, nerve injury, stiffness, implant loosening, and wear. The likelihood and relevance of each risk varies by clinician and case, and not every complication applies to every patient.

Q: How much does THA cost?
Costs vary widely by country, insurance coverage, facility, surgeon and anesthesia fees, implant selection, length of stay, and rehabilitation needs. Many health systems provide preoperative estimates, but exact totals can be difficult to predict in advance because needs may change during recovery.