Evolving Technique: Metallosis, Trunnionosis, Modular Stems and - - PowerPoint PPT Presentation

Adult Reconstruction

Evolving Technique: Metallosis, Trunnionosis, Modular Stems and Pseudotumors: What I Do in 7 Minutes

William A. Jiranek MD, FACS Professor and Vice Chair Duke University Orthopaedic Summit 2017 Las Vegas, Nev.

• Dec. 6-9, 2017

Disclosure

• Personal

– Royalties

• Depuy

– Consultant

• Depuy

– BOD and Committee

• AAHK

S, Hip Society

• Institution

– Research and clinical support:

• Depuy
• Stryker

Adverse Local Tissue Response (ALTR) – Metal on Poly

Revision for unexplained pain is uncommon (2%), and revision for metal problems (1%) and lysis (2%)

ALTR – Trunionnosis What do we know

• Vague groin or trochanteric

Pain

• Little relation to activity

Is it occuring more frequently or are we just recognizing more Big Heads More offset different alloys?

Diagnostic Workup (Jacobs, Rush)

• Radiographs showed osteolysis of the proximal femur in seven hips (26%),

generally seen in the area of the calcar or at the base of the greater trochanter

• ESR and CRP elevated in 14/27 pts

– ESR: 32 mm/hr (3.0 – 113) – CRP: 3.8 mg/dL (<0.5 – 19.9)

• Aspirations performed in 21 of 27 pts

– Mean WBC count 6,939 WBC/μL (range, 2 to 55,500)

• Mean 62% neutrophils (range,

12% to 99%)

– WBC elevated in 6 cases

• All preop/introperative cultures

negative

• All frozen sections negative for

acute inflammation

Plummer, D.R. J. Arthrop 31:264–268, 2016.

Metal Levels

• Elevated Co levels in all 27 cases
• Elevated Cr levels in 22 of 27 cases
• Serum Co levels were differentially

elevated over serum Cr levels

Ion Mean Range Referenc e 1 Co 11.2 ppb 1.1 – 49.8 (0.16 ± 0.10) Cr 2.2 ppb 0.16 – 9.8 (0.24 ± 0.35)

1 Jacobs, ORS 2002

(p = 0.014, Wilcoxon signed-rank test)

Serum Cobalt

• Serum cobalt is the best test for diagnosis
• f suspected ALTR following MoP THA

– Optimal cut-off value of 1.0 ng/mL – Much lower than threshold for MOM bearings!

• Serum Chromium also of value
• Cobalt typically higher than Chromium

Patients with a serum Cobalt > 1 ng/mL should undergo further evaluation for an ALTR secondary to corrosion

YA Fillingham et al. J Arthroplasty 32 (9S), S272-S277. 2017 Apr 20.

75 yo male 1 yr s/p uncomplicated right THA, now with troch pain dxed as troch bursitus

Surgery for ALTR – trunionnosis

• Identify the angle and the

type of taper, ensure that you can obtain a sleeve

• Thorough Debridement
• Mechanically clear taper
• Use ceramic head on a

titanium sleeve

• Recovery is slower and

instability is common – 7% in Rush series

Solutions for Trunionnosis

Options with abductor damage

What about Modular femoral components?

• If revising for trunionnosis –

consider revising stem

• May need ETO for removal of

modular stem

Adverse Local Tissue Response (ALTR) – Metal on Metal

• While placement of metal on metal

devices is rare today, there are lots out there

Background Methods Results Significance

Comparing ASR and Pinnacle Cohorts

Key Findings

• ASR – earlier timing to MRI, higher Cobalt (and Ratio)
• No other significant differences
• Pseudotumor Findings:
• Similar prevalence, size, and category

Background Methods Results Significance

Factors Associated With Pseudotumor Presence

Key Findings

• Patients with pseudotumor more likely to have:
• Higher cobalt levels (and ratio)
• High offset femoral component
• Larger acetabular component

Background Methods Results Significance

Pseudotumor Not Correlated With Symptoms

Key Findings

• Symptomatic vs Asymptomatic:
• Similar metal ion levels
• Similar pseudotumor prevalence, size,

and category

• Pseudotumor present in 47% of

asymptomatic patients

*

*Symptomatic patients defined as having pain and/or weakness/limp

Background Methods Results Significance

Conclusions: Effects of Pseudotumors In Patients

• Overall high prevalence of pseudotumor in patients with MoM THA and MRI (52%)
• Nearly 40% of pseudotumors either thick-walled cystic lesions or solid lesions
• Factors significantly correlated with pseudotumor presence:
• Elevated Cobalt ion levels and CoCr ratio
• High offset stem
• Increasing cup size
• Patient symptoms may not be reliable indicator of pseudotumor presence or severity
• 38% of pseudotumors were in asymptomatic patients, no correlation with severity
• In asymptomatic cohort, pseudotumor prevalence was 47%
• Revised patients have higher ion levels and more frequent and severe pseudotumors

High Rates of Post-Revision Complications

Cohort ASR Pinnacle P-value (n = 106) (n = 50) (n = 56) Timing 0.0077 Early (<5 years) 45 (42%) 28 (56%) 17 (30%) Late (>5 years) 61 (58%) 22 (44%) 39 (70%) Patients w/ Complications 25 (24%) 11 (22%) 14 (25%) 0.7165 Revised for ARMD 15 (60%) 9 (82%) 6 (43%) 0.0484 Total Complications 31 14 16 Early (<5 years) 19 8 11* *0.0001 Late (>5 years) 11 6 5*

ASR implants were revised significantly earlier Nearly 1 in 4 patients experienced a complication Revised Pinnacle implants were significantly likely to result in complication if revised within 5 years (All Pinnacle dislocations (n = 6) occurred within the early cohort) Background Methods Results Significance

MRI Imaging and Ion Levels – Complications

Revisions Complication No Complication P-value (n = 106) (n = 25) (n = 81) Pseudotumor Presence 49 (46%) 6 (of 12 MRIs) 43 (of 62 MRIs) 0.1944 Greatest Length (cor or sag) 7.5 (6.5) 11.6 (8.2) 7.0 (6.4) 0.3303 Volume 228.7 (49.8) 872.4 (164.8) 153.8 (45.9) 0.1039 Category 20:15:14 1:2:3 19:13:11 0.1526 Cobalt 32.6 (12.6) 50.1 (24.5) 29.2 (12) 0.0435 Chromium 18.4 (5.3) 21.6 (16) 17.8 (3.8) 0.0889 Ratio 3.9 (2.5) 5.1 (2.9) 3.6 (2.4) 0.6205

Continuous variables recorded as Average (Median)

No significant correlation between experiencing post-revision complication and pseudotumor presence, size, chromium level, or Co/Chr ratio Positive correlation between post-revision complication and cobalt levels Background Methods Results Significance

Conclusion

• Trunion corrosion and MOM metallosis act differently
• Metal threshold in MOP - 1 ppb Cobalt
• MOP Cobalt > chromion
• MOM Cobalt / Chromion

Moving forward. Climbing higher. Moving forward. Climbing higher.