Freezing of orthopaedic specimens before mechanical testing.

Area of Science:

• Orthopedics
• Biomechanical Engineering
• Tissue Science

Background:

• Understanding the biomechanical effects of cryopreservation on musculoskeletal tissues is crucial for surgical planning and tissue engineering.
• Previous research has focused on cellular viability, with less attention paid to macroscopic structural changes.

Purpose of the Study:

• To investigate the effects of sub-zero temperature storage and thawing on dissected musculoskeletal tissues.
• To quantify changes in muscle and tendon length and joint mobility post-cryopreservation.

Main Methods:

• Dissected muscles, tendons, limbs, and spines were subjected to sub-zero storage.
• Specimens were thawed, and changes in muscle and tendon length were measured.
• The range of passive joint movement was assessed before and after freezing-thawing cycles.
• Myotomy or tenotomy was performed on some specimens before freezing to assess the impact on deformity.

Main Results:

• Freezing induced significant shortening in muscles, which was reversible upon thawing.
• Tendons exhibited less pronounced, but still noticeable, shortening after freezing.
• Specimens with myotomy or tenotomy developed deformities due to unopposed muscle shortening during freezing.
• Thawed specimens with muscles and joints demonstrated an increased range of passive motion.

Conclusions:

• Sub-zero storage significantly alters the mechanical properties of muscles and tendons, causing reversible shortening.
• The integrity of opposing muscle groups is critical in preventing deformities during cryopreservation.
• Thawing musculoskeletal tissues results in enhanced joint mobility, potentially beneficial for certain therapeutic applications.