Does Patient-Specific Instrumentation Have a Higher Rate of Early Osteolysis Than Standard Referencing Techniques in Total Ankle Arthroplasty? A Radiographic Analysis

Abstract

Introduction: Patient-specific instrumentation (PSI) has been developed for total ankle arthroplasty (TAA), with proven benefits. One concern regarding PSI is the need for more soft tissue dissection in order to accurately position the PSI guides, which has the theoretical disadvantage of increased osteolysis. The purpose of our study is to compare the incidence and magnitude of osteolysis for the INFINITY Total Ankle System between PSI and standard referencing (SR) techniques. Methods: Sixty-seven patients who underwent primary TAA using Prophecy (PSI) or SR technique between 2013 and 2015 were reviewed in a retrospective observational study. Osteolysis was assessed on radiographs at 2 years. The incidence was calculated by binomial distribution. The number of zones compromised and the magnitude of osteolysis was calculated using the median as a summary statistic and interquartile range as dispersion statistic. Fisher exact test was used to compare both groups, then a regression model was estimated to calculate the odds ratio for osteolysis. Results: Of the 67 TAAs, 51 were in the PSI group and 16 in the SR group. In the PSI group the incidence, number of compromised zones (CZ), and magnitude was 41% (25%-59%), 1 [1-2], and 2 [2-3], respectively. In the SR group these were 36% (13%-65%), 3 [2-3], and 3 [2-4], respectively. No significant differences were found ( P = .46, P = .12, P = .33). A slightly higher risk of osteolysis was found in the PSI group (odds ratio = 1.33 [0.36-4.83]) ( P = .46). The majority of lesions were in 1 zone with size of 2 to 5 mm (63% for all cohort, 64% PSI, 60% SR). Two cases underwent revision for aseptic loosening, 1 in the SR group and 1 in the PSI group. Conclusion: According to our data, there is no significant difference between PSI and SR in terms of risk, incidence, size and magnitude of osteolysis in the INFINITY Total Ankle System at 2 years. Levels of Evidence: Therapeutic, Level III, Retrospective cohort study

Patient-Specific Instrumentation vs Standard Referencing in Total Ankle Arthroplasty: A Comparison of the Radiologic Outcome

“…This is of concern because it may carry the risk of impaired bony ingrowth of the implants. Escudero et al found a slightly higher, though not significant, risk of osteolysis in the PSI group compared with SR. 10 This agrees with our findings, wherein a trend for a higher risk for radiolucent lines was observed in the PSI group (2 vs 1 case in the SR group). However, the numbers in the current study are too low to conclude whether the increased intraoperative damage to the periarticular bone affects the incorporation of the implants in TAA, and more research is needed before a conclusion can be drawn.…”

Two-Year Outcomes After Total Ankle Replacement With a Novel Fixed-Bearing Implant

“…Unlike this present study, high rates of tibial component osteolysis have been reported in several studies ranging from 31% to 41%. 7,20…”

Outcomes and Complications of the INFINITY Total Ankle: A Systematic Review

“…All 14 were examined for inclusion and exclusion, which resulted in 6 total published studies with clinical outcomes (Figure 1). 11,[14][15][16][17][18] All were retrospective. Four were level IV and 2 were level III studies.…”