A Coding System for Reoperations Following Total Ankle Replacement and Ankle Arthrodesis

Background: Repeated surgery can be a measure of failure of the primary surgery. Future reoperations might be avoided if the cause is recognized and procedures or devices modified accordingly. Reoperations result in costs to both patient and the health care system. This paper proposes a new classification system for reoperations in end-stage ankle arthritis, and analyzes reoperation rates for ankle joint replacement and arthrodesis surgeries from a multicenter database. Methods: A total of 213 ankle arthrodeses and 474 total ankle replacements were prospectively followed from 2002 to 2010. Reoperations were identified as part of the prospective cohort study. Operating reports were reviewed, and each reoperation was coded. To verify inter- and intraobserver reliability of this new coding system, 6 surgeons experienced in foot and ankle surgery were asked to assign a specific code to 62 blinded reoperations, on 2 separate occasions. Reliability was determined using intraclass correlation coefficients (ICCs) and proportions of agreement. Results: Of a total of 687 procedures, 74.8% (514/687) required no reoperation (Code 1). By surgery type, 14.1% (30/213) of ankle arthrodesis procedures and 30.2% (143/474) of ankle replacement procedures required reoperation. The rate for reoperations surrounding the ankle joint (ie, Codes 2 and 3) was 9.9% (21/213) for ankle arthrodesis versus 5.9% for ankle replacement (28/474). Reoperation rates within the ankle joint (ie, Codes 4 to 10) were 4.7% (10/213) for ankle arthrodesis and 26.1% (124/474) for ankle replacement. Overall, 0.9% (2/213) of arthrodesis procedures required reoperation outside the initial operative site (Code 3), versus 4.6% (22/474) for total ankle replacement. The rate of reoperation due to deep infection (Code 7) was 0.9% (2/213) for arthrodesis versus 2.3% (11/474) for ankle replacement. Interobserver reliability testing produced a mean ICC of 0.89 on the first read. The mean ICC for intraobserver reliability was 0.92. For interobserver, there was 87.9% agreement (804/915) on the first read, and 87.5% agreement (801/915) on the second. For the intra observer readings, 88.5% (324/366) were in agreement. Conclusions: The new coding system presented here was reliable and may provide a more standardized, clinically useful framework for assessing reoperation rates and resource utilization than prior complication- and diagnosis-based classification systems, such as modifications of the Clavien Dindo System. Analyzing reoperations at the primary site may enable a better understanding of reasons for failure, and may therefore improve the outcomes of surgery in the future. Level of Evidence: Level III, retrospective comparative cohort study based on prospectively collected data.