Original article
Mechanical changes induced by thermal stimulation in collagenous tissue

https://doi.org/10.1016/j.jse.2007.06.015Get rights and content

Radiofrequency thermal stimulation is used as a therapeutic procedure for joint laxity, but its thermal effects are still controversial. Although collagen shrinkage may be expected, this conclusion is empirical and not universally accepted. The purpose of this study was to investigate the mechanical response of collagen to thermal stimulation. A longitudinal cut was made in rabbit Achilles tendons previously marked with monofilament sutures. The distance between the sutures was measured before the cut, just after it was made, and after 8 weeks. The results did not show any shrinkage or significant change in tendon resistance to traction 8 weeks after thermal stimulation; however, comparison with the opposite, normal tendon revealed a statistically significant increase in tendon stiffness.

Section snippets

Materials and methods

The study used 12 New Zealand White rabbits supplied by the same breeder. The animals were 4 to 6 months old, and their mean weight was 2.5 kg. The study was conducted in the Biological Research Institute of the Health and Environment State Department in the State of Rio Grande do Sul (Instituto de Pesquisas Biológicas da Secretaria Estadual da Saúde e do Meio Ambiente do Rio Grande do Sul), Brazil. Animal care followed ethical norms and animal experimentation legislation established by

Results

No significant differences were found in the measurements of the area between the monofilament nylon sutures at cauterization and at 8 weeks.

The data in the load vs deformation graph obtained from the stress tests (Figure 1) provided the tendon rupture point (TRP), which represents the load (N) necessary for tendon rupture, and the tendon elasticity coefficient (TEC), calculated according to the curve slope in the area of elastic deformation (N/mm).

The results described in Table I were obtained

Discussion

The laxity of capsule and ligament structures and the consequent joint instability are difficult to resolve posttraumatic sequelae, even for an experienced orthopedist. The large number of surgical techniques reported in the literature reinforces the idea that the results of treatment of these tissues are not always as expected, and clinical outcomes can be unsatisfactory. Moreover, several of these techniques cause an initial weakening of these capsular and ligament structures, which requires

References (15)

There are more references available in the full text version of this article.
View full text