total hip arthroplasty/replacement (THA, THR)

Introduction

This includes replacement of the head of the femur & the acetabulum. Also see hemiarthroplasty of hip.

Classification

• metal-on-polyethylene implant (traditional) (metal femoral heads with polyethylene cups) result in
• metal-on-metal implant (newer); out of favor
• ceramic-on-ceramic implants (newer)

Indications

• end-stage hip osteoarthritis
  • radiographic evidence of moderate-to-severe hip osteoarthritis
  • moderate-to-severe pain, loss of function, or both
  • no improvement with physical therapy or joint injection
• osteonecrosis of the femoral head
• hip fracture
• femoroacetabular impingement

* better option than hemiarthroplasty of hip for healthier potentially more mobile patients due to better walking ability & quality of life

* elective total hip arthroplasty has not been compared with nonsurgical management in randomized trials

* recommendations from conditional, not strong

Contraindications

• morbid obesity does NOT seem to be contraindication
• obesity regardless of BMI not a contraindication
• delay for poorly-controlled diabetes mellitus, but HgbA1c requirements are not defined
• delay for trial of smoking cessation

* recommendations from conditional, not strong

Complications

• hip movements that may lead to posterior dislocation:
  • flexion
  • adduction (most important)
  • internal rotation past the neutral point
• pneumonia
• pressure ulcers
• constipation
• delirium (40%)
  • poor preoperative performance on Mini-Cog test predicts postoperative delirium
  • long-term cognitive trajectories similar to individuals with total hip arthroplasty
• deep vein thrombosis
  • 20% after unilateral THA, 60% of these proximal DVT
  • complete resolution of DVT in 6 months WITHOUT anticoagulation
  • NO pulmonary embolism WITHOUT anticoagulation
• peripheral nerve injuries
• prosthesis infection
• loosening of hardware
• mean total blood loss 1500 mL of which 470 mL is hidden mean drop in hemoglobin is 3 g/dL
• ectopic bone formation in surrounding tissue
• metal-on-metal hip implants are not associated with an increased risk for cancer
• increased risk of myocardial infarction (25-fold at 2 weeks, returning to basline at 6 weeks)
• risk for revision: 10-year implant survival is 96%; 20-year implant survival is 85%
• overlapping surgery associated with an increased risk for surgical complications
  • increasing duration of operative overlap associated with an increasing risk for complications
• 30 day major postoperative complication rate is 5.0%
  • if BMI >= 40 kg/m2 postoperative complication rate is 6.7%
  • 14 obese patients would need to be denied surgery to prevent 1 30-day major complication
• complications slightly more common with an anterior than with a lateral or posterior approach

Management

• general
  • do not delay for trials of physical therapy, NSAIDs, bracing, intra-articular glucocorticoid injections, or hyaluronic acid injections (conditional recommendation)
  • frailty assessment
  • routine placement of indwelling urinary catheter is unnecessary when patients undergo total hip replacement under spinal anesthesia
  • perioperative antibiotic prophylaxis with cefazolin monotherapy
  • anticoagulation for 2-4 weeks, 4-5 weeks
    • see prophylaxis for venous thromboembolism
    • ted hose & pneumatic compression device until ambulatory
    • enoxaparin 40 mg SQ QD
    • Active Care + SFT may be alternative to enoxaparin
    • advantage of warfarin or LMW heparin, compared with aspirin or mechanical prophylaxis not obvious
    • LMW heparin for 10 days plus aspirin for 28 days as good as LMW heparin for 38 days
    • rivaroxaban 10 mg QD for 14 days
    • rivaroxaban 10 mg QD for 5 days followed by aspirin 81 mg QD for 9 days as effective as rivaroxaban for 14 days
    • rivaroxaban for 38 days may be better
    • aspirin associated with lower 30-day mortality than other agents
      • no difference in symptomatic pulmonary embolism or symptomatic proximal DVT, incidence of serious bleeding or death for enoxaparin 40 mg QD vs aspirin 100 mg QD for 35 days
        • small difference in distal (below knee) DVT favoring enoxaparin
  • if prosthesis is cemented in place, immediate weight-bearing as tolerated
  • non-cemented components rely on ingrowth of bone for stabilization of joint; limit weight-bearing for 6 weeks
  • active assisted range-of-motion exercises immediately postoperative
  • delay full range of motion exercises to prevent dislocation
  • muscle stengthening, resistive exercises 6-8 weeks postoperatively
  • out of bed on 1st post-operative day
  • ambulation with physical therapy assistance on 2nd post-operative day
  • bisphosphonate use is associated with a lower rate of revision after hip arthroplasty & knee arthroplasty & longer implant survival
  • threshold for urinary catheterization of 800 mL rather than 500 mL may prevent unnecessary catheterization
• anesthesia & analgesia
  • regional anesthesia relative to general anesthesia is associated with:
    • fewer surgical site infections (3 per 1000)
    • fewer cardiovascular complications (5 per 1000)
    • fewer respiratory complications (4 per 1000)
    • fewer prolonged hospital stays (5% vs 7% for >= 7 days)
    • no difference in 30 day mortality
    • spinal anesthesia associated with less pain, less opioid use & fewer intensive care unit admissions than general anesthesia
  • acetaminophen 1000 mg + ibuprofen 400 mg 1 hour before surgery & every 6 hours afterward for 24 hours reduces need for PRN morphine
  • acetaminophen 1000 mg + ibuprofen 400 mg TID & dexamethasone 24 mg QD superior to acetaminophen + ibuprofen
  • morphine 15-24 mg for breakthrough pain
  • perioperative gabapentinoids associated with excess pulmonary complications & do not spare opioid use
• posterior approach
  • adduction splint placed between the legs when the patient is in bed if patient unable to comply with positioning instructions
  • a raised toilet seat to minimize hip flexion
  • limit time in a seated position to no more than 30 minutes at a time to prevent hip dislocation & joint flexion contracture
• Goals of rehabilitation:
  • maintain full joint range of motion
  • prevent joint contracture
  • strengthen periarticular musculature
  • restore gait
  • prevent dislocation of artificial joint
  • unsupervised home exercises are as effective as formal post-hospitalization physical therapy for selected patients with good home support
• exercise interventions:
  • supervised preoperative & postoperative exercise interventions not associated with improved self-reported physical function
  • preoperative exercise for obese patients can improve postoperative functional mobility & increase the likelihood of discharge home
• patients with rheumatic diseases
  • DMARDs methotrexate, leflunomide, hydroxychloroquine, sulfasalazine may be continued during the perioperative period
  • biologics (adalimumab, etanercept ..)
    • withhold for one dosing schedule before elective surgery
    • resume with evidence of wound healing (minimum of 14 days)
    • no increase in infections when infliximab given within 4 weeks of hip replacement or knee replacement
• metformin reduces need for THA/THR 30% in patients with type 2 diabetes
• RED FLAGS
  • sudden or steady increase in pain
    • infection
    • loosening of hardware

Notes

• revision arthroplasty higher for newer metal on metal & ceramic-on-ceramic implants than traditional metal-on-polyethylene implants
• failure rates for the metal on metal implants, especially among women are > 10%; 6%
• cobalt-chromium surfaces of metal-metal implants can wear down, leading to the release of Co+2 at levels in excess of workplace-exposure limits of 5.0 ug/L in the blood
• metal-on-metal implants with 5-year failure rates resulting in revision rate 3-fold higher than other bearing types, ~ 6% vs 2%
  • larger metal-on-metal head sizes were most prone to failure
• ceramic-on-ceramic prostheses have better performance with larger head size
• women & obese most at risk for metal-on-metal implant failure
• ~8% of hip arthroplasties in the U.K. performed using new devices without evidence of effectiveness
• ceramic-on-ceramic bearings, modular femoral necks, & high-flexion implants associated with higher rates of revision
• 89%, 70%, & 58% of total hip replacements lasted 15, 20, & 25 years, respectively

More general terms

• arthroplasty

Additional terms

• hemiarthroplasty of hip
• prophylaxis for venous thromboembolism (VTE)

Patient information

total hip arthroplasty/replacement patient information