Download Previous subtalar fusion increases nonunion rate for primary open

Previous subtalar fusion
increases nonunion rate for
primary open ankle
arthrodesis
Ornusa Chalayon, Bibo Wang,
Brad Blankenhorn, J. Benjamin Jackson III,
Florian Nickisch, Timothy Beals,
Charles L Saltzman
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Introduction
• Arthrodesis of the ankle is the mainstay of
treatment for advanced arthritis.
• Both the patient (host) and surgical (treatment)
factors determine the success of the fusion.
• Study objective: to identify any factors that affect
the surgical outcome in straightforward, “noncomplicated” ankle fusions
Materials & Methods
• Retrospective chart review study
• Inclusion criteria : Patients underwent primary open
ankle arthrodesis at the University of Utah’s facilities
over an eleven-year period (March 2002 to January
2013, who had a minimum of 6 months follow-up X-rays
• Exclusion criteria :
- neuropathic arthropathy or insensate limb
- failed total ankle replacement
- simultaneous arthrodesis of the subtalar joint
- fusions performed within 1 year of ankle injury to salvage failed fixation
and painful function due to 1) open fractures, 2) segmental bone loss >1
cm, 3) infection , 4) talar body fractures
Materials & Methods
• Primary outcome : radiographic union by 6 months after
surgery, as defined by the plain radiographs
• Secondary outcome : postoperative complications
• Potential predictor variables : age, gender, weight and
height, underlying medical condition(s), history of
smoking and alcohol consumption or illicit drug use,
etiology of arthritis, preoperative ankle alignment, history
of a prior subtalar fusion and the surgical technique used
for ankle arthrodesis
• Statistical analysis : multivariable mixed effect Poisson
regression
Results
• 528 ankle fusion surgeries were performed on
440 patients at our institution during the study
period
• 215 ankle fusion surgeries in 209 patients met
inclusion/exclusion eligibility criteria for noncomplicated open ankle fusions
• 91% overall union rate
Univariate analysis identified elicit drug used and
previous subtalar fusion as potential predictor
factors of ankle fusion nonunion.
After using a multivariable mixed effect Poisson
regression model to test these two factors,
previous subtalar fusion remained a significant risk
factor for nonunion.
Risk factors
Univariate analysis
Multivariate analysis
Risk ratio
P-value
Risk ratio
P-value
Elicit drug use
5.31
0.06
3.28
0.12
Previous subtalar fusion
4.18
0.03
3.06
0.048
Complications
• Diabetes was not a significant risk factor of either
deep or superficial infection, with a relative risk of
1.62 (p = 0.54) and 1.12 (p = 0.84), respectively.
• For presumed infection treated surgically, smoking
had a relative risk of 11.36, with a marginal
significance of p=0.08.
• Smoking also elevated the risk of ultrasound proven
venous thromboembolism: 5 times when compared
to the controls (p = 0.04).
Discussion/Conclusion
• Ankle arthrodesis failed in 9% of noncomplicated ankles with arthritis
• Patients who had an ankle fusion done after the
arthrodesis of subtalar joint had significantly
higher rate of non-union
• Smoking is associated with increased risk of
complications.