Total Hip Replacement Surgery

Total hip replacement surgery — formally termed total hip arthroplasty — is one of the most performed elective orthopedic procedures in the United States, with the American Academy of Orthopaedic Surgeons (AAOS) reporting more than 450,000 procedures performed annually. This page covers the definition and anatomical scope of the procedure, the mechanical and surgical process, the clinical scenarios that lead to it, and the criteria surgeons use to determine candidacy. Understanding this procedure matters because outcomes vary substantially based on implant type, surgical approach, and rehabilitation protocol.

Definition and Scope

Total hip replacement involves removing the damaged or diseased articulating surfaces of the hip joint and replacing them with prosthetic components designed to replicate the joint's ball-and-socket function. The hip joint — formed by the femoral head (ball) and the acetabulum (socket) in the pelvis — bears loads estimated at 2 to 3 times body weight during normal walking, and up to 8 times body weight during stair climbing, according to biomechanical data published by the American Academy of Orthopaedic Surgeons.

The procedure falls under the broader category of joint replacement surgery, which is addressed within the orthopedic surgical quality and safety framework maintained by the Centers for Medicare & Medicaid Services (CMS) through its Comprehensive Care for Joint Replacement (CJR) bundled payment model. CMS uses this model to hold hospitals accountable for the cost and quality of an entire 90-day episode of care for lower extremity joint replacements.

For readers seeking the broader regulatory environment governing orthopedic procedures, the regulatory context for orthopedics on this site provides the foundational framework.

A standard total hip replacement addresses four prosthetic components:

1. Acetabular shell — a metal cup pressed or screwed into the reshaped acetabulum
2. Acetabular liner — an insert (polyethylene, ceramic, or metal) that forms the bearing surface inside the cup
3. Femoral stem — a metal component implanted into the femoral canal to anchor the prosthesis
4. Femoral head — a ball (typically ceramic or metal) that attaches to the stem and articulates with the liner

How It Works

The surgical process involves several discrete phases, from preoperative planning through implant fixation.

Phase 1 – Preoperative templating: Surgeons use calibrated plain radiographs or CT-based 3D modeling to select implant sizes and plan leg-length equalization. Digital templating software registered against imaging has largely replaced acetate overlays in most hospital systems.

Phase 2 – Approach selection: The surgical approach determines which muscles and capsular structures are divided. The three most common approaches are:
- Posterior (Moore/Southern): High visualization, higher historical dislocation risk without capsular repair
- Anterolateral (Watson-Jones): Moderate soft tissue disruption, commonly used in direct lateral variants
- Direct anterior (Smith-Petersen): Internervous, intermuscular plane; associated with faster early recovery in peer-reviewed data from the Journal of Bone and Joint Surgery, though long-term outcomes are equivalent across approaches

Phase 3 – Bone preparation: The acetabulum is reamed to a hemispherical shape; the femoral canal is broached to accept the stem. Limb-length discrepancy is assessed intraoperatively using bony landmarks or navigation systems.

Phase 4 – Fixation: Implants are secured via cementless press-fit (relying on bone ingrowth into porous surfaces) or cemented fixation (using polymethylmethacrylate bone cement). Hybrid constructs — cementless acetabular cup, cemented stem — are also employed, particularly in patients with compromised femoral bone stock.

Phase 5 – Bearing surface selection: Bearing couples vary in wear characteristics. Highly cross-linked polyethylene liners against ceramic femoral heads have demonstrated wear rates below 0.05 mm per year in retrieval studies (AAOS OrthoInfo). Metal-on-metal bearings fell out of widespread use following FDA safety communications beginning in 2012 due to adverse local tissue reactions.

Common Scenarios

Total hip replacement is most frequently performed for three primary diagnoses:

• End-stage osteoarthritis: Progressive cartilage loss leading to bone-on-bone contact. For a detailed discussion of this disease process, see the page on osteoarthritis.
• Avascular necrosis (osteonecrosis) of the femoral head: Loss of blood supply causing femoral head collapse; etiologies include corticosteroid use, alcohol use disorder, sickle cell disease, and trauma.
• Femoral neck fractures: Displaced femoral neck fractures in older adults — particularly those with pre-existing arthritis — are frequently managed with total hip arthroplasty rather than hemiarthroplasty to reduce revision rates. The American Geriatrics Society's perioperative guidelines address hip fracture management timing.

Less common indications include inflammatory arthritis (rheumatoid and other spondyloarthropathies), post-traumatic arthritis following acetabular fractures, and oncologic resection requiring reconstruction.

Decision Boundaries

Candidacy for total hip replacement is not defined solely by imaging findings; it requires convergence of radiographic severity, functional impairment, and failure of non-operative management. The AAOS Clinical Practice Guidelines for hip osteoarthritis specify that conservative measures — including physical therapy, weight management, and pharmacological pain management — should be attempted before surgical referral is considered appropriate.

Factors supporting surgery:
- Radiographic joint space narrowing to Kellgren-Lawrence Grade 3 or 4
- Functional limitation unresponsive to 3 to 6 months of structured conservative care
- Pain at rest or nighttime pain disrupting sleep

Factors requiring additional evaluation or creating relative contraindications:
- Active joint or systemic infection (absolute contraindication per AAOS guidelines)
- Morbid obesity (BMI ≥ 40) — associated with higher complication rates including periprosthetic joint infection; risk-benefit discussion required
- Severe peripheral vascular disease compromising wound healing
- Medical comorbidities requiring optimization before anesthesia clearance

Implant longevity data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) — one of the largest arthroplasty registries in the world — shows 15-year cumulative revision rates of approximately 8 to 10% for primary total hip replacement, with higher revision rates in patients under 55 years of age. This age-related revision risk is a central factor in the surgical decision for younger patients.

The procedure interfaces with a broader orthopedic care continuum, including postoperative rehabilitation (see recovering from joint replacement), and is governed by device regulations enforced by the U.S. Food and Drug Administration (FDA) under 21 CFR Part 888, which classifies orthopedic implants and sets premarket notification (510(k)) or premarket approval (PMA) requirements for hip prosthesis systems. The full orthopedics authority index provides additional context on related procedures and care pathways.

References

• American Academy of Orthopaedic Surgeons (AAOS) – OrthoInfo: Total Hip Replacement
• Centers for Medicare & Medicaid Services – Comprehensive Care for Joint Replacement (CJR) Model
• U.S. Food and Drug Administration – 21 CFR Part 888: Orthopedic Devices
• Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR)
• American Geriatrics Society – Clinical Practice Guidelines for Perioperative Care in Hip Fracture
• AAOS Clinical Practice Guideline – Management of Osteoarthritis of the Hip

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