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Updated: 9/25/2021

THA Trunnionosis

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https://devupload.orthobullets.com/topic/422821/images/pseudotumor.jpg
  • summary
    • THA Trunnionosis is a complication of hip arthroplasty caused by metal ion release from tribocorrosion at the femoral head-neck interface morse taper leading to hip pain and adverse local tissue reactions.
    • Diagnosis can be suspected in a patient with elevated serum metal ions with cobalt levels being elevated more substantially than chromium levels. MRI studies can be helpful to assess for pseudotumors. 
    • Treatment is observation for patients without symptoms. Single stage revision THA is indicated for patients with a painful THA in the absence of an infection. 
  • Epidemiology
    • Risk factors
      • modular designs
      • large cobalt chrome femoral heads
        • larger heads may put more torsional forces on the trunnion.
      • taper design
        • shorter taper length may afford less interference fit and more micromotion
        • greater rigidity of the taper may lead to less wear
      • metal on metal
        • serum metal ions may contribute to taper wear
        • no pathognomonic serum metal ion level for trunnionosis
        • serum cobalt >1 ng/ml (ppb) should lead to consideration for mechanically assisted crevice corrosion (MACC)
      • mixed alloy components
  • Etiology
    • Pathophysiology
      • Galvanic corrosion
        • corrosion caused by an electrochemical transfer of electrons between dissimilar metals
          • i.e. cobalt-chromium (CoCr) alloy femoral head on a titanium alloy stem
      • Fretting corrosion
        • corrosion from relative micromotion between two materials causing wear
          • i.e. tolerance between male and female morse taper allows for micromotion and wear
          • contributes to trunniononsis
      • Crevice corrosion
        • physicochemical interaction between a metal and environment leading to altered mehcanical properties
        • stainless steel most prone to crevice corrosion
  • Presentation
    • History
      • pain and limp are the most common complaints
    • Physical exam
      • occasionally if ALTR is large enough a palpable pseudocyst can be felt
      • abduction weakness if ALTR has caused soft tissue destruction of abductors
  • Imaging
    • AP and lateral hip views should be obtained
      • imaging studies may be normal in the setting of trunnnionosis
    • Judet views and/or CT scan may be obtained if advanced osteolysis is present
    • MARS MRI
      • findings may include periarticular pseudotumors and/or soft tissue destruction
  • Studies
    • Infection should be ruled out
      • ESR, CRP, WBC
      • Aspiration
        • consider manual cell count as metal debris can cause a false elevation of automated cell count
    • Metal ion levels
      • cobalt and chromium ion levels
        • cobalt levels may be elevated more substantially (4-5x) than chromium levels
  • Treatment
    • Operative
      • revision total hip
        • indications
          • painful THA with the above risk factors and elevated serum cobalt level compared to serum chromium level elevation
        • technique
          • frozen-sections and intraoperative cultures
          • extensive synovectomy
          • inspection of the taper and decision for retention of stem versus revision stem
          • to ceramic head with titanium sleeve and new polyethylene liner

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(OBQ18.246) Figure A depicts the intraoperative findings during a revision total hip arthroplasty (THA) in a patient with chronic pain for the last two years after undergoing his index THA 10 years ago. Workup for infection was negative. The acetabular and femoral components are assessed to be well-fixed intraoperatively. Which of the following describes the best treatment option?

QID: 213142
FIGURES:
1

Suppressive intravenous antibiotics

0%

(1/1807)

2

Two-stage revision arthroplasty

2%

(30/1807)

3

Irrigation and debridement

1%

(26/1807)

4

Acetabular component revision

4%

(64/1807)

5

Revision to new ceramic femoral head with titanium sleeve

93%

(1674/1807)

N/A A

Select Answer to see Preferred Response

(OBQ18.32) An 81-year-old man reports a year of worsening right groin pain and swelling. A current radiograph and recent MRI are shown in Figures A and B, respectively. ESR and CRP are within normal limits. Aspiration yields 8cc of black liquid with an automated cell count of 7,000 WBC. Manual cell count demonstrates 1,500 WBC and 62% neutrophils. Serum cobalt levels are 12ppb and chromium levels at 2ppb. What is the next best step in management?

QID: 212928
FIGURES:
1

Greater trochanteric bursa injection

1%

(15/1902)

2

Revision arthroplasty with exchange of both components to long modular diaphyseal engaging stem and multihole acetabular cup

7%

(132/1902)

3

Revision arthroplasty with exchange of both components to long modular diaphyseal engaging stem and constrained acetabular component

3%

(63/1902)

4

Revision arthroplasty with antibiotic spacer placement and subsequent revision arthroplasty

3%

(57/1902)

5

Revision arthroplasty with conversion to ceramic head with titanium sleeve and new polyethylene liner

85%

(1614/1902)

L 2 A

Select Answer to see Preferred Response

Evidence (2)
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EXPERT COMMENTS (2)
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