Photobiomodulation (PBMT) at 1064 nm is increasingly being studied in musculoskeletal disorders, particularly shoulder tendinopathies. A recent study published in the Journal of Clinical Medicine (2026) analysed the biological effects of different treatment doses on cells involved in rotator cuff pathology, using the HIRO TT system.
The study highlights how the biological response depends on the management of the energy transfer and on the correct therapeutic dose, offering relevant insights for clinical practice.
The study: focus on treatment parameters and biological response
The study analysed:
- tenocytes, involved in tendon remodelling and repair processes;
- cells derived from the subacromial bursa, associated with the peri-inflammatory component.
Cells isolated during rotator cuff repair were subjected to PBMT with HIRO TT using doses ranging from 1.5 to 6.0 J/cm² and two different emission intensity modulations for several consecutive days.
Cell metabolic activity was assessed using the XTT assay and morphological observation, allowing the study of the relationship between energy transfer and cellular response, a central theme in photobiomodulation.
Results: the response is not straightforward
Tenocytes
A clear dose-dependent response was observed in tenocytes, with a favourable therapeutic window at medium-high doses. Specifically, the most effective conditions were 4.5 and 6.0 J/cm².
A significant increase in metabolic activity was observed in these groups compared to the control, while other parametric combinations proved less effective or inhibitory.
The increase in metabolic activity suggests a favourable modulation, induced by the laser treatment, of tendon tissue remodelling and adaptation processes.
Burse cells:
Burse cells showed a more variable and less homogeneous response than tenocytes, suggesting that different tissues may require different parametric strategies even within the same anatomical region.
This data reinforces the concept of biologically customising laser treatment based on the tissue target.
Energy dose, emission management, and the role of Hiro TT
The study highlights how the biological response is closely linked to the dose, the energy transfer management, and the characteristics of the treated tissue target.
Even small variations in parameters can significantly alter the cellular response, confirming the importance of systems capable of ensuring control, stability, and reproducibility of the therapeutic emission.
In the clinical context, Hilterapia® fully meets these requirements thanks to high-peak power and high-intensity pulsed emissions, combined with a dynamic pulse control system with real-time monitoring of the emitted energy, capable of ensuring high repeatability of the therapeutic emission, deep and controlled energy transfer, and high tissue tolerability.
The study represents a significant preclinical contribution towards a greater biological understanding of the HIRO TT/Hilterapia® technology and a further step forward in optimising protocols for tendon and peritendinous applications.
Since the study was conducted with HIRO TT, the biologically effective parameters observed refer to these specific pulse characteristics and cannot be automatically extended to other 1064 nm systems with different emission modes.
