Foot & Ankle

Evaluating the learning curve for total ankle arthroplasty

There is undoubtedly a learning curve for every procedure that we carry out, and this has particularly come into focus in the arthroplasty world, where outcomes are increasingly being shown to be affected by volume. Increased experience has been shown to be associated with a decrease in peri-operative and post-operative complications and, in hip arthroplasty surgery at least, to be associated with longevity. The exact number of cases required in total ankle arthroplasty for this learning curve to stabilise remains unclear. In this paper from Milan (Italy), an analysis was performed of the learning curve for a single fellowship-trained foot and ankle surgeon who was not an implant designer.³ The first 46 cases of primary total ankle arthroplasty performed were included in the study; however, patients undergoing any additional procedures were excluded from the study, leaving a final study population of 31 patients. These patients underwent isolated primary total ankle arthroplasty for ankle arthritis using the HINTEGRA total ankle prosthesis. Outcome evaluation took place at six, 12 and 24 months, and assessment included the American Orthopaedic Foot and Ankle Society (AOFAS) ankle and hindfoot score, visual analogue scale (VAS) for pain and the SF-12. An objective assessment of range of movement was performed along with a radiological assessment of weight-bearing radiographs. Intra-operative metrics were collected and post-operative complications were recorded. An assessment of the learning curve was made by examining the relationship between surgeon experience and patient outcome at 24 months. The learning curve stabilised in terms of surgical time after the fourteenth patient. There was also, perhaps most surprisingly, a learning curve appreciable in clinical outcomes and measurable with the VAS score, ankle range of movement and AOFAS score of 11, 14 and 28 patients, respectively. The authors were able to establish a learning curve associated with the sagittal alignment of the talar component but not when examining for alignment on any other measure used in the study method. There are clearly limitations to the generalisability of a study of this nature. Overall surgeon experience, exposure to ankle arthroplasty as a trainee, prosthesis ease of use and prosthesis design all affect the learning curve and cannot be factored into this study. However, the results from this surgeon do suggest that there is a learning curve that did affect overall patient-reported outcomes for the initial 28 cases.