ABSTRACT
[Objective]To explore the mechanism of hip joint capsule contracture induced by intragluteal injection. [Method]Thirty young Chinese rabbits were divided into four groups of A(n=6),B(n=6),C(n=6) and D(n=12) at random.Rabbits in groups A,B and C were treated with deep intragluteal injection of penicillin dissolved in 2% benzyl alcohol(group A),2% benzyl alcohol(group B)and penicillin dissolved in physiologic saline(group C).Rabbits in group D were treated with immobilization of unilateral hip joint and deep intramuscular injection of physiologic saline on the homolateral buttock.Each rabbit was injected twice a day for 20 days.Specimens were obtained at 30,60 and 90 days after first injection and the evaluation of the functions of hind limbs was obtained at the same time.The thickness of hip joint capsules were measured with micrometer and sections of joint capsules were stained by Sirius red and were observed with microscope and polarization microscope.[Result]Capsules of hip joint in group A and B became thicker and contractural,and the change of joint capsules was reflected in the change of motion of hind limbs.Sections in groups A and B showed shrinked capsules with thick collagens in disordered arrangement;while there were no gluteus contracture and contracture of joint capsule in the other groups.[Conclusion]Deep intragluteal injection of penicillin dissolved in 2% benzyl alcohol or 2% benzyl alcohol into young rabbits can cause contracture of hip joints.The contracture of joint capsule is largely induced by tissue trauma and repair of joint capsules.The limited locomotion of hip joint induced by the contracture of gluteal muscle does not play an important role in the contracture of joint capsule.