Document Type : Original Articles

Authors

• Zahra Sadat Rezaeian ¹
• Giti Torkaman ²
• Alireza Sabbaghian ³
• Ali Esteki ⁴
• Roya Ravanbod ⁵
• Masumeh Dadpey ⁶

¹ PhD candidate of physical therapy, School of Medical Sciences, Tarbiat Modares University, Tehran, Iran

² Professor, Department of Physical Therapy, School of Medical Sciences, Tarbiat Modares University, Tehran, Iran

³ Orthopedic Sergeon, Akhtar Hospital, Tehran, Iran

⁴ Professor, Department of Physics and Medical Engineering, Shahid Beheshti University of Medical Sciences, Tehran, Iran

⁵ PhD in Physical Therapy, Hemophilia Comprehensive Treatment Center, Tehran, Iran

⁶ Assistant Professor, Department of Pathology, Army Medical School, Tehran, Iran

Abstract

Introduction: The anterior cruciate ligament (ACL) is one of the most important factors in knee stability and motion control so that its injuries result in serious movement problems for patients. The present study clarifies the effect of unilateral ACLT on histological and biomechanical properties of articular cartilage of rabbit knee.Materials and Methods: Ten skeletally mature Dutch white male rabbits were divided into 2 groups. In the surgery group, left anterior cruciate ligament was completely transected through midshaft. Histopathological properties, biomechanical charachteristics and thickness of femoral and tibial articular cartilage in left knee measured at 62nd day post surgery. Normal group underwent no intervention in the same period. Biomechanical characteristics of tibial medial plateau and femoral medial condyle studied by means of the ex vivo biphasic stress–relaxation test. Maximal force, elastic modulus, equilibrium force and aggregate modulus were extracted from these data. Data were statistically analyzed via Mann-Whitney U test. To avoid error in histological sample reading, histological study performed on tibial lateral plateau and femoral lateral condyle.Results: In ACLT group, both femoral and tibial cartilages deteriorated. In comparison to normal group, cartilage thickness in ACLT group decreased significantly only in femoral medial condyle (P = 0.009). All biomechanical parameters of femoral condyle were significantly less than normal group (P < 0.05). The only exception was aggregate modulus that was almost the same in both groups. Biomechanical properties of tibial plateau were not statistically different between the two groups.Conclusion: Although the structural deterioration of articular cartilage in femoral condyle was less severe than tibial plateau within the first 9 weeks following complete ACLT, functional deterioration was significant only in femoral condyle. However, tibial plateau saved its biomechanical charachtristics despite significant degeneration. The biomechanical and histological alteration of the rabbit articular cartilage described in present study provides further evidence that this small animal model exhibits changes identical to secondary osteoarthritis.Keywords: Anterior cruciate ligamnet transaction, Articular cartilage, Biomechanics, Secondary osteoarthritis, Rabbit