Hemiarthroplasty: Definition, Uses, and Clinical Overview

Posted on February 27, 2026 | by drhip

Hemiarthroplasty Introduction (What it is)

Hemiarthroplasty is a joint replacement surgery where only one side of a joint is replaced.
In the hip, it typically replaces the femoral head (the “ball”) while leaving the natural socket in place.
It is commonly used after certain hip fractures, especially in older adults.
It can also be performed in other joints, but the hip is the most well-known example.

Why Hemiarthroplasty used (Purpose / benefits)

Hemiarthroplasty is used to restore joint function and reduce pain when the natural joint surface is damaged in a way that is unlikely to heal reliably with fixation alone. In hip care, the most common problem it addresses is a femoral neck fracture (a break just below the femoral head) where blood supply to the femoral head may be compromised. In these scenarios, repairing the fracture with screws or a plate may carry a risk of nonunion (failure to heal) or osteonecrosis (bone tissue damage related to poor blood flow). Replacing the femoral head can help bypass those risks.

At a high level, the purpose is to:

Relieve pain by removing damaged bone and cartilage at the femoral head.
Restore the hip’s ability to bear load by placing a prosthetic femoral head on a stable femoral stem.
Support earlier mobilization compared with some fracture-fixation pathways, depending on the fracture pattern and patient factors.
Reduce reoperation risk in selected fractures where the native femoral head is less likely to remain viable (this varies by clinician and case).

Hemiarthroplasty is considered a “partial” replacement because the acetabulum (hip socket) is not routinely resurfaced or replaced. This distinction matters because keeping the native socket may preserve bone and reduce operative complexity, but it can also introduce trade-offs such as wear or pain arising from the natural socket over time.

Indications (When orthopedic clinicians use it)

Common clinical situations where Hemiarthroplasty may be considered include:

Displaced femoral neck fracture, particularly in older adults
Femoral neck fracture with concern for femoral head viability (risk of osteonecrosis varies by fracture type and timing)
Certain complex fractures where stable internal fixation is less predictable
Selected cases of femoral head damage where replacing only the femoral side is deemed appropriate (varies by clinician and case)
Salvage situations after failed fixation of a femoral neck fracture (case-dependent)
In other joints (less commonly discussed in general hip education), partial joint replacement concepts may be applied when one articular surface is primarily involved (indication details vary by joint)

Contraindications / when it’s NOT ideal

Hemiarthroplasty is not the right fit for every patient or every hip problem. Situations where it may be less suitable, or where another approach may be preferred, can include:

Advanced acetabular cartilage wear or symptomatic hip arthritis: a total hip arthroplasty (replacing both ball and socket) may be considered instead (varies by clinician and case).
Active infection in or around the joint: implanting a prosthesis in an infected field is typically avoided, and staged strategies may be used.
Severe acetabular bone loss or deformity: retaining the native socket may not provide a durable, comfortable articulation.
High functional demands where acetabular wear is a concern: total hip arthroplasty may be considered depending on age, activity level, and anatomy.
Neuromuscular conditions or instability risks: implant choice and approach may differ, and other reconstructions may be preferred (varies by clinician and case).
Medical instability where surgery is not tolerated: non-operative management or temporizing strategies may be considered, depending on fracture type and patient goals.

These are general concepts. Final decision-making depends on fracture pattern, bone quality, pre-injury mobility, cognitive status, medical comorbidities, and surgeon assessment.

How it works (Mechanism / physiology)

Hemiarthroplasty works by replacing the damaged femoral head with a prosthetic head attached to a femoral stem inside the thigh bone (femur). The new prosthetic “ball” is designed to move smoothly against the patient’s natural acetabulum (hip socket). The basic biomechanical goal is to recreate a stable ball-and-socket joint that can transmit body weight through the hip with less pain and improved function.

Key hip anatomy involved includes:

Femoral head and neck: the “ball” and the narrowed bridge beneath it; common sites of fracture in older adults.
Acetabulum: the socket in the pelvis; in hemiarthroplasty it is typically left intact.
Articular cartilage and labrum: the cartilage lines the socket; the labrum is a rim of soft tissue that helps seal the joint.
Hip capsule and ligaments: soft tissues that contribute to stability.
Hip abductors (gluteus medius/minimus) and other muscles: important for gait mechanics and preventing a limp.
Bone quality: affects fixation method and implant stability.

Onset of effect: Pain relief and mechanical stability are typically immediate in the sense that the fractured or damaged femoral head is removed and replaced during surgery. However, comfort and function often improve gradually as soft tissues heal and strength returns.

Duration and reversibility: Hemiarthroplasty is not reversible in the way a medication is. It is a reconstructive surgery intended to be durable, but longevity varies by implant design, fixation method, patient factors (activity level, bone quality), and whether acetabular wear develops over time. In some cases, a hemiarthroplasty can later be converted to a total hip arthroplasty if the socket becomes painful or worn (varies by clinician and case).

Hemiarthroplasty Procedure overview (How it’s applied)

Hemiarthroplasty is a surgical procedure performed in an operating room with sterile technique and anesthesia. The exact steps vary by surgeon, hospital protocol, and patient anatomy, but the general workflow often includes:

Evaluation/exam – History, physical exam, and assessment of baseline mobility and health conditions. – Imaging (often X-rays; additional imaging may be used depending on the scenario). – Discussion of surgical goals and expected functional pathway (varies by clinician and case).
Preparation – Pre-operative medical assessment and anesthesia planning. – Surgical planning, including implant sizing and fixation strategy (cemented vs uncemented). – Positioning and surgical approach selection (approach varies by surgeon preference and patient factors).
Intervention – Exposure of the hip joint through a chosen approach. – Removal of the damaged femoral head and preparation of the femoral canal. – Placement of the femoral stem (cemented or press-fit/uncemented) and attachment of the prosthetic head. – Reduction of the joint (placing the prosthetic head into the native socket) and assessment of leg length, stability, and range of motion.
Immediate checks – Intraoperative stability checks and closure of tissues. – Post-operative imaging may be obtained to confirm implant position (practice varies). – Early monitoring for pain control, mobility status, and medical stability.
Follow-up – Wound review, monitoring for complications, and functional progression. – Rehabilitation planning and reassessment of gait, strength, and safety with daily activities (specific plans vary).

This overview is intentionally high-level; operative technique details and protocols differ by institution and clinical situation.

Types / variations

Hemiarthroplasty is not a single uniform implant. Common variations include:

Unipolar vs bipolar hemiarthroplasty
Unipolar: a single prosthetic head articulates directly with the patient’s acetabulum.
Bipolar: an additional inner bearing allows motion between components of the implant as well as between the implant and acetabulum.
The choice is influenced by surgeon preference, patient factors, and implant system; comparative outcomes can vary by clinician and case.
Cemented vs uncemented (press-fit) femoral stems
Cemented: bone cement secures the stem within the femur; often considered when bone quality is poor.
Uncemented: the stem is sized to achieve a press-fit and may rely on bone growth over time for long-term fixation.
Risks and benefits differ; selection varies by patient bone quality, anatomy, and surgeon experience.
Head size and offset options
Surgeons select prosthetic dimensions to optimize stability, restore biomechanics, and address leg length and soft-tissue tension (exact targets vary by case).
Surgical approach variations
Approaches differ in muscle dissection patterns and may influence early precautions and stability considerations (varies by clinician and case).
Material and bearing surface choices
Femoral heads and stems are commonly metallic alloys; specific materials and coatings vary by manufacturer.
Longevity and wear behavior depend on design and material pairing and cannot be generalized to a single “best” option.

Pros and cons

Pros:

Preserves the native acetabulum, which may reduce the amount of bone replaced
Often used for certain femoral neck fractures where fixation may have higher failure risk
Can restore a stable hip articulation after fracture-related disruption
May allow a more predictable path to mobilization than some fixation strategies in selected patients (varies by clinician and case)
Typically shorter reconstruction than replacing both sides of the joint (case-dependent)
Can be converted to total hip arthroplasty later if the socket becomes problematic (not always necessary)

Cons:

The native acetabulum can develop pain or wear over time because it articulates with a prosthetic head
Hip dislocation is a recognized complication after arthroplasty procedures, influenced by approach, soft tissues, and patient factors
Infection, blood clots, and medical complications are possible after major orthopedic surgery
Leg length differences or altered hip biomechanics can occur despite careful intraoperative assessment
Periprosthetic fracture (fracture around the implant) can occur, particularly with falls or poor bone quality
Some patients may ultimately require conversion to total hip arthroplasty if symptoms persist (varies by clinician and case)

Aftercare & longevity

Aftercare following Hemiarthroplasty generally focuses on wound healing, safe mobility, and gradual restoration of strength and walking mechanics. Hospital protocols differ, and rehabilitation plans are individualized based on:

Reason for surgery: fracture patients may have different recovery trajectories than elective indications.
Pre-injury function and mobility: baseline walking ability, balance, and use of assistive devices can shape recovery milestones.
Weight-bearing status and precautions: these are determined by the surgical team based on implant fixation and intraoperative findings, and they vary by clinician and case.
Rehabilitation participation: physical therapy often emphasizes gait training, transfers (bed/chair), and strengthening of hip and core muscles.
Comorbidities: osteoporosis, diabetes, kidney disease, heart/lung conditions, and neurologic disorders can affect healing and endurance.
Cognitive status and home support: these influence safety with mobility and adherence to post-operative instructions.
Falls risk: falls can jeopardize early recovery and increase the risk of dislocation or periprosthetic fracture.

Longevity depends on multiple interacting factors rather than a single timeline. Important influences include implant fixation method (cemented vs uncemented), implant design and materials (varies by material and manufacturer), patient activity level, bone quality, and whether acetabular cartilage tolerates the prosthetic articulation over time. Follow-up schedules and imaging practices vary; ongoing monitoring is typically used to evaluate symptoms, function, and implant position.

Alternatives / comparisons

The “right” approach depends on diagnosis, patient health, and goals. Common alternatives or comparators to Hemiarthroplasty include:

Internal fixation (pins/screws/plates)
Often considered for certain femoral neck fractures, particularly when preserving the patient’s own femoral head is feasible.
Fixation aims to let bone heal, but healing potential and femoral head blood supply concerns vary by fracture pattern and patient age.
Total hip arthroplasty (THA)
Replaces both the femoral head and the acetabulum.
May be considered when the socket is already arthritic, when long-term acetabular wear is a concern, or when functional demands support a full replacement (varies by clinician and case).
THA can offer durable pain relief for arthritis but may involve different dislocation risk profiles and operative considerations compared with hemiarthroplasty.
Non-operative management
In frail or medically unstable patients, or in select fracture types, non-operative care may be discussed.
It generally focuses on comfort, positioning, and mobility planning; expected functional outcomes vary widely and depend on the underlying injury and patient condition.
Conservative care for non-fracture hip pain (when applicable)
For arthritis or tendinous conditions (not fractures), non-surgical options can include activity modification, physical therapy, and medications.
These options do not “replace” a fractured femoral head; they apply to different diagnoses and goals.

Comparisons are rarely one-size-fits-all. Clinicians weigh bone quality, fracture displacement, acetabular status, pre-injury independence, and surgical risk when selecting among these strategies.

Hemiarthroplasty Common questions (FAQ)

Q: Is Hemiarthroplasty the same as a total hip replacement?
No. Hemiarthroplasty replaces only the femoral head (the ball), while a total hip replacement replaces both the ball and the socket. The choice depends on factors like the condition of the acetabulum, the diagnosis (such as fracture vs arthritis), and patient-specific considerations.

Q: How painful is recovery after Hemiarthroplasty?
Pain levels vary by person, surgical approach, and the reason for surgery. Many patients have pain from the original injury (such as a fracture) that changes in character after surgery, and post-operative pain management is typically part of routine care. Day-to-day discomfort often improves as tissues heal and mobility returns, but timelines vary by clinician and case.

Q: How long does a hemiarthroplasty last?
Longevity depends on implant design, fixation method, bone quality, activity level, and whether the natural socket develops wear or pain over time. Some patients do well long-term, while others may develop acetabular symptoms that lead to further evaluation. If problems occur, conversion to total hip arthroplasty can be considered in selected cases.

Q: What are common risks or complications?
As with other major joint surgeries, potential complications include infection, dislocation, blood clots, bleeding, nerve or blood vessel injury, fracture around the implant, and anesthesia-related complications. Individual risk is influenced by overall health, bone quality, and surgical factors. Discussing personalized risk is part of standard pre-operative counseling, and it varies by clinician and case.

Q: Will I be able to walk right away after surgery?
Early mobilization is common after hip arthroplasty procedures, but the timing and weight-bearing status depend on the implant fixation method, the quality of bone, and intraoperative findings. Some patients begin standing and walking with assistance soon after surgery, while others require a more gradual progression. Rehabilitation plans are individualized.

Q: When can someone drive or return to work after Hemiarthroplasty?
Timing varies based on pain control, mobility, reaction time, which side was operated on, and job demands. Sedating medications and limited hip control can affect driving safety, and certain work tasks may be restricted during early recovery. Clinicians typically individualize guidance based on function and healing progress.

Q: What is the difference between bipolar and unipolar hemiarthroplasty?
Unipolar implants have a single head that moves against the natural socket. Bipolar implants include an additional internal bearing intended to allow some motion within the implant as well as at the socket interface. Whether one design is preferred depends on surgeon experience, patient factors, and implant system; outcomes can vary by clinician and case.

Q: Does Hemiarthroplasty treat hip arthritis?
It can, but it is not the most common choice for primary hip arthritis when the acetabulum is also involved. Because hemiarthroplasty leaves the socket intact, it may not address acetabular cartilage loss and can lead to persistent pain if the socket is already arthritic. Total hip arthroplasty is more commonly used for symptomatic end-stage hip arthritis.

Q: How much does Hemiarthroplasty cost?
Costs vary widely by country, hospital setting, insurance coverage, implant selection, length of stay, and rehabilitation needs. The total cost often includes surgeon and anesthesia fees, facility charges, imaging, medications, and post-acute care. For patient-specific estimates, billing departments and insurers typically provide the most accurate breakdown.