Risk factors for rerupture after conservative management of acute Achilles tendon rupture

Abstract

Category: Sports Introduction/Purpose: Recently, results after conservative management for acute Achilles tendon rupture have been improving after the introduction of real time assessment of tendon healing using ultrasonography and introduction of early weight-bearing and functional brace. Yet, many surgeons prefer surgical management of all acute ruptures due to the risk of tendon rerupture. The purposes of this study are to evaluate incidence and pattern of rerupture of Achilles tendon after complete healing, and to investigate factors related to it. Methods: A total of 202 patients with acute Achilles tendon rupture, who underwent conservative management with cast(3 to 7 weeks) and functional brace, were the subjects of this study. In patients having both tendons injured, only one side was randomly selected for analysis. Hence, for 202 patients, migration free survivorship was analyzed using Kaplan-Meier method, and association with possible risk factors was analyzed by Cox regression analysis using proportional hazards model. Factors include age, sex, history of Achilles tendinopathy, cast duration, calf atrophy(mean calf circumference difference at least 2 cm), possibility of SHR(single heel raise), Achilles thickness after complete healing, and insufficient opposition of tendon ends(10mm>gap>5 mm) after cast, initial gap with ankle neutral. Results: Rerupture occurred in 7 of 202 patients. Factors significantly associated with rerupture in Kaplan-Meier survivorship analysis and univariate Cox regression analysis were sex, history of Achilles tendinopathy, calf atrophy, possibility of SHR. When these factors were analyzed by multivariate analysis, possibility of SHR was the only significant factor with a hazard ratio of 3.14. Conclusion: Our data suggest that possibility of SHR requires special attention during the follow-up. The risk of rerupture after conservative management of acute Achilles tendon rupture can be reduced by sufficient recovery of calf muscle strength with early weightbearing and accelerated rehabilitation with aid of ultrasonography.