Novel adjuvant therapy for heat-assisted capsular shift procedures

Heat-Assisted Capsular Shift (HACS) procedures are currently applied to treat shoulder (glenohumeral) instability. The therapy aims at thermally denaturing the collagenous framework, thus shrinking the surrounding soft tissues of the lax glenohumeral joint. The desired outcome of the therapy is restoring the kinematic stability of the joint without degrading its mechanical stability. Reports describing the outcome of HACS procedures reveal considerable variations, most likely due to utilization of different heat deposition modalities and the diversity of the thermal treatment protocols applied. The uncertainty of the outcome is also amplified by the post-heating recovery from shrinkage and the heat-induced degradation of mechanical stability. This study introduces a novel method designed to minimize the adverse effects of current therapies. A mechanical property enhancement technique in the form of an adjuvant chemical treatment is presented. In-vitro experiments performed on rabbit patellar tendons using a new arthroscopic fluid with thermal treatment indicate therapeutic improvement compared to therapies based on heating alone. A decrease in the strain recovery as large as 50% and an increase in stiffness as much as 100% have been produced in collagenous tissues without compromising strength. In summary, this work presents the initial results of an effort aimed at increasing the safety and reliability of currently applied HACS procedures by optimal manipulation of novel thermo-chemical treatments.