Background: Management of chronic Achilles tendon rupture (ATR) typically involves demanding surgery, frequently with the use of grafts, and requires prolonged rehabilitation.

Purpose: This study aims at trialing a novel non-invasive treatment method Autologous Bone Marrow-Derived Mesenchymal Stem Cells (aBM-MSC)

Study Design: Case series

Methods: Six patients with magnetic resonance imaging (MRI) confirmed symptomatic partial or total chronic ATR were treated with percutaneous intratendinous injection of expanded 20x10e6 aBM-MSCs. Cells were injected percutaneously, under sonographic control, in the damaged tendon area.

Results: Six patients were followed up for a minimum of 24 months. aBM-MSC treatment was safe and well tolerated. MRI showed maximum regeneration gradient of Achilles tendon tissue in all patients by the last visit. Patients reported significantly reduced pain [median scores: VAS (-8.5), VAS sport (-9.7), and improved VISA-A (86.5)]. All patients returned to their pre-injury daily activities immediately and to recreational sports activities by four months post-injection.

Conclusions: Percutaneous intratendinous injection of 20x10e6 cultured aBM-MSCs is effective, feasible and safe and should be considered a promising option in the personalized treatment of chronic ATR.

Clinical Relevance: A new development in the treatment of ATR that overcomes the current difficulties in relation to surgical management such as increased risk of complications, limited weight bearing, immobilization and a faster return to sports.