Functional Trajectory and Quality of Life Divergence Following Surgical Versus Conservative Management of Achilles Tendon Contracture in Monozygotic Twins with Duchenne Muscular Dystrophy: A Case Report.

Background: The timing and efficacy of Achilles tendon lengthening (ATL) in Duchenne muscular dystrophy (DMD) remain controversial because indiscriminate surgery can accelerate ambulation loss. Case Description: This report presents a 5-year longitudinal comparative analysis (2021-2026) of monozygotic twins with identical genetic backgrounds (DMD exon 30-43 deletion) who received comparable rehabilitation and pharmacological management, including concurrent gene therapy in 2025. Twin A was managed conservatively with orthosis and subsequent serial casting for progressive equinus contracture, whereas Twin B underwent early bilateral ATL during transition to the non-ambulatory phase. Despite a temporary postoperative decline, Twin B demonstrated a more stable longitudinal motor trajectory, outperforming Twin A in gross motor function (Gross Motor Function Measure-88: 38.60% vs. 32.85% in 2026) by preserving residual standing and crawling dimensions. Longitudinal KIDSCREEN-52 assessments revealed a clinically meaningful improvement in psychological well-being in Twin B (+10.9 points) relative to Twin A. Conclusions: This single-pair twin case serves as a hypothesis-generating observation, highlighting a potential longitudinal association between early surgery and attenuated progressive motor decline within a multi-disciplinary care regimen. Given highly variable psychosocial outcomes, these trends cannot be directly attributed to surgery alone. When evaluating such orthopedic interventions, clinical decisions may benefit from looking beyond immediate gait metrics toward broader, long-term functional trends, though the relative contributions of concurrent therapies remain to be elucidated.