CUHK Achilles Tendon Disorder Registry

This is a prospective, longitudinal Achilles Tendon Registry study. The registry is conceived as a foundational cohort study designed to systematically address critical evidence gaps in the management of Achilles tendon pathologies. The Achilles tendon, while robust, is susceptible to a spectrum of disorders including acute ruptures and chronic tendinopathies, often summarized colloquially as the "Achilles heel." Current clinical management strategies for these conditions are characterized by heterogeneity, largely due to a paucity of high-quality, longitudinal comparative effectiveness data. This registry aims to mitigate this gap by creating a centralized repository of standardized, prospective data, thereby enabling rigorous evaluation of treatment outcomes, prognostic factors, and long-term sequelae.

The primary objective is to establish a comprehensive, prospectively enrolled cohort of individuals with Achilles tendon disorders, complemented by a cohort of asymptomatic controls, to facilitate comparative and predictive analyses. The study is explicitly designed to answer three pivotal research questions. First, it will investigate the prognostic influence of baseline structural and vascular status of the tendon, as quantified by ultrasonographic and elastographic metrics, on functional recovery. Second, it will assess whether a pre-existing diagnosis of Achilles tendinopathy constitutes a significant risk factor for subsequent acute tendon rupture. Third, it will analyze differential treatment responsiveness, aiming to identify which patient subgroups, defined by specific baseline characteristics, demonstrate optimal outcomes with specific treatment modalities.

The study methodology is that of a prospective, single-center cohort study to be conducted at the Prince of Wales Hospital in Hong Kong. The target sample size is a minimum of 500 participants, to be consecutively enrolled from 2025 to 2028. The participant pool will include adults over the age of 18 with a diagnosis of an Achilles tendon disorder, as well as asymptomatic control participants without tendon pathology. Key exclusion criteria encompass any comorbid physical or psychological condition that would impair the ability to complete study assessments or provide informed consent, and concomitant diseases that severely affect lower limb function (e.g., severe osteoarthritis, prior amputation, active inflammatory arthritis, or paralysis).

The follow-up protocol is structured into intensive initial and long-term phases. All participants will undergo comprehensive in-person assessments at baseline, 6 weeks, 3 months, 6 months, and 1 year post-enrollment. These assessments constitute the core data collection points and encompass a multi-modal battery of outcome measures. Following the initial 1-year follow-up, the protocol transitions to long-term monitoring, wherein all self-reported outcome measures will be collected annually via online questionnaires at years 2, 3, 4, and 5.

The primary outcome measure is the Victorian Institute of Sports Assessment-Achilles (VISA-A) questionnaire, a validated, disease-specific patient-reported outcome tool scored from 0 to 100. A comprehensive suite of secondary outcome measures will be collected to provide a holistic assessment. These include patient-reported outcomes such as the Numeric Pain Rating Scale (NPRS) and the Foot and Ankle Outcome Score (FAOS). Functional and physical performance measures are integral and consist of the Achilles Tendon Resting Angle (ATRA), calf muscle strength quantified via hand-held dynamometry, the heel raise endurance test, and a one-legged counter-movement jump test performed on a pressure mat. Biomechanical analysis includes foot pressure distribution assessment and treadmill-based gait analysis using a Zebris system.