Abstract
Category:
Hindfoot; Ankle Arthritis
Introduction/Purpose:
Screw prominence in the heel following calcaneal fixation has resulted in unacceptably high rates of symptomatic hardware and subsequent screw removal. The hardware removal rate following calcaneal screw fixation ranges from 11-50%. We are unaware of any cost analysis comparing headed screw fixation vs. headless screw fixation in the foot and ankle literature. Furthermore, there is no literature comparing the rate of subtalar arthrodesis following headed screw fixation vs. headless screw fixation.
Methods:
CPT codes were used to identify all patients that had a subtalar arthrodesis or displacement calcaneal osteotomy (with screw fixation) performed by a single orthopedic foot and ankle surgeon between 2010 and 2016. The cohort was divided into two groups by the type of screw fixation, 7.0 mm headless screw or 6.7 mm headed screw. Exclusion criteria included <2 years from the index surgery and AVN of the calcaneus or talus. Retrospective chart review was performed to collect demographic data, complications, and cause for screw removal. The primary outcome measure was the rate of symptomatic screw removal.
Secondary outcome measure included subtalar arthrodesis as determined by CT or radiographic review. The expense associated with symptomatic hardware removal was determined and cost analysis was performed for the two groups.
Results:
Seventy-six patients underwent headless screw fixation for calcaneal osteotomy or subtalar arthrodesis, and only two patients (2.6%) required symptomatic screw removal. Fifty-four patients underwent headed calcaneal screw fixation, and twelve patients (22.2%) required symptomatic screw removal. Symptomatic hardware removal was performed more frequently in the headed screw group (p< 0.001). There was no difference in the rate of nonunion after subtalar arthrodesis between the two groups (p = 0.363). The calcaneal osteotomy healed in 100% of patients in both groups. The cost associated with isolated screw removal was compared for private insurance and Medicare at an outpatient surgery center. There was a $51,755 cost savings per 100 cases using headless screw fixation compared to headed screw fixation.
Conclusion:
The rate of symptomatic screw removal following calcaneal osteotomy or subtalar arthrodesis is lower with headless screw fixation compared to headed screw fixation. There was no difference in the rate of subtalar union between the two groups as a secondary outcome, but the study was underpowered. Although the headless screw implant is more expensive, cost analysis demonstrates a significant benefit when the expense of hardware removal is considered.
