The healing effects on the biomechanical properties of joint capsular tissue treated with Ho:YAG laser: An in vivo rabbit study.
OBJECTIVE
The objective of this study was to evaluate the healing response, after thermal treatment with a Ho:YAG laser, on the biomechanical properties of capsular soft tissue.


METHODS
Before and after trial.


METHODS
Forty-five New Zealand white rabbits were used in this study. A medial peripatellar retinacular thermal capsuloplasty using a Ho:YAG laser and a lateral peripatellar retinacular release was performed on 1 knee of each rabbit. The contralateral knee served as a control and had a lateral release of the retinaculum only. The temperature of the medial retinaculum was maintained at 55 degrees C +/- 5 degrees C during treatment. The medial peripatellar retinaculum was evaluated at 0, 6, and 12 weeks postoperatively. Tensile testing of the medial retinaculum and a biomechanical assessment evaluating the structural and material properties were performed.


RESULTS
The ultimate load (force) of the medial retinaculum was 70%, 56%, and 84% of control at 0, 6, and 12 weeks, respectively, after the procedure. The stiffness (force/deformation) of the medial retinaculum was 83% of control at 0 weeks, 54% at 6 weeks, and 85% at 12 weeks. The ultimate stress (force/area) of the medial retinaculum also showed a significant reduction at 0 and 6 weeks postoperatively, 63% and 62% of control, respectively. By 12 weeks, the ultimate stress was 83% of control.


CONCLUSIONS
Thermal treatment of the medial retinaculum with a Ho:YAG laser results in soft tissue with significantly diminished biomechanical properties after treatment. The results of this study suggest that a 12-week period of minimal stress on the capsular tissues should follow a thermal capsuloplasty procedure.
Schulz
M M
MM
Orthopaedic Biomechanics Laboratory, Veterans Affairs Medical Center, Long Beach, CA 90822, USA.
Lee
T Q
TQ
Sandusky
M D
MD
Tibone
J E
JE
McMahon
P J
PJ
D000818:Animals; D001696:Biomechanical Phenomena; D004548:Elasticity; D017746:Joint Capsule / Q000503:physiopathology* / Q000601:surgery*; D007719:Knee Joint / Q000503:physiopathology / Q000601:surgery; D053685:Laser Therapy / Q000009:adverse effects* / Q000379:methods; D011817:Rabbits; D013314:Stress, Mechanical; D013718:Tensile Strength; D016474:Weight-Bearing; D014945:Wound Healing