Objective To discuss the stabil ity and practical ity of temporomandibular joint replacement by establ ishing goats artificial temporomandibular joint replacement model. Methods Six healthy mature goats were selected, the male and female being half and weighing 35.3-37.0 kg. According to the parameters from X-ray films of goat’ s temporomandibular joint and the shape of the same kind goat’s skull, the total temporomandibular joint prosthesis was prepared. The one side temporomandibular joints of six goats were replaced by prosthesis randomly as the experimental group (n=6, fossa and condyle according to replacement location) and the other side by titanium plate as the control group (n=6). At 4,8, and 12 weeks, the histological observation, scanning electron microscope (SEM) observation were carried out for observing structural changes in the interface. The mechanical test and histochemistry test were used for observing the combination degree of interface and the alkal ine phosphatase (ALP) activity. Results All animals were al ive to the end of experiment with normal open mouth, good recovery of masticatory function, and normal eating. At 4, 8, and 12 weeks, implants were stable in 2 groups without loosening. The histological observation and SEM observation showed the amount of osteoblasts in interface increased over times. There were significant differences in the shearing force and the ALP activity between fossa in experimental group and control group at 4 weeks (P lt; 0.05), but there was no significant difference between other groups (P gt; 0.05). Conclusion The total temporomandibular prosthesis has good stabil ity in temporomandibular joint reconstruction of goat after replacement.
To evaluate the changes in stabil ity of the wrist after experimental traumatic triangular fibrocartilage complex (TFCC) lesions, and to provide basic theoretical criteria for cl inical treatment. Methods Fourteen adult cadaver upper extremities specimens were included. Two of 14 specimens were tested in pre-experiment. The specimens were tested in a INSTRON 8874 biomechanics measuring instrument. First a dorsal arthrotomy (ART) was performed, and second test was with 1 of 4 different experimental lesions according to Palmer’s classification of traumatic TFCC lesions (n=3). 1A: central perforation; 1B: ulnar avulsion with or without fracture of processus styloideus ulnae; 1C: distal avulsion with l igament injury; 1D: radial avulsion. Forced internal∕external rotation torque were recorded in the interval — 60° to 60° of flexion. Results The average torque of the dorsal ART was (0.713 ± 0.121) Nm, and the 1B-1 lesion (ulnar avulsion without ulnar styloid fracture) was (0.709 ± 0.134) Nm, the 1B-2 lesion (ulnar avulsion with ulnar styloid fracture) was (0.409 ± 0.113) Nm. The difference between the 1B-1 lesion and the dorsal ART was not significant but the difference between the 1B-2 lesion and the dorsal ART was significant (P lt; 0.05). The average torque of the 1C lesion in about 45° of wrist extention and flexion were (0.878 ± 0.184) Nm and (0.988 ± 0.197) Nm, and the dorsal ART were (1.510 ± 0.173) Nm and (1.540 ± 0.093) Nm. The difference between the two groups was significant (P lt; 0.05). The 1A lesion and 1D lesion did not alter significantly wrist stabil ity. Conclusion The 1B-2 lesion and 1C lesion alter significantly the stabil ity of the wrist.
【Abstract】 Objective To determine the three-dimensional stabil ity of atlantoaxial reconstruction withanterior approach screw fixation through C2 vertebral body to C1 lateral mass and Gall ie’s technique (ASMG) for C1,2instabil ity. Methods Twenty-five human cadaveric specimens (C0-3 ) were divided randomly into 5 groups (n=5). Thethree-dimensional ranges of motion C1 relative to C2 were measured under the five different conditions：the intact state group (group A), type II odontoid fracture group (group B), posterior C1,2 transarticular screw fixation group (group C), ASM group (group D) and ASMG group (group E). The three-dimensional ranges of motions C1 relative to C2 by loading ± 1.5 Nm were measured under the six conditions of flexion/extension, left/right lateral bending, and left/right axial rotation. The obtained data was statistically analyzed. Results In each group, the three-dimensional ranges of motion C1 relative to C2 under the six conditions of flexion/extension, left/right lateral bending, and left/right axial rotation were as follows: in group A (8.10 ± 1.08), (8.49 ± 0.82), (4.79 ± 0.47), (4.93 ± 0.34), (28.20 ± 0.64), (29.30 ± 0.84)°; in group B (13.60 ± 1.25), (13.80 ± 0.77), (9.64 ± 0.53), (9.23 ± 0.41), (34.90 ± 0.93), (34.90 ± 1.30)°; in group C (1.62 ± 0.10), (1.90 ± 0.34), (1.25 ± 0.13), (1.37 ± 0.28), (0.97 ± 0.14), (1.01 ± 0.17)°; in group D (2.03 ± 0.26), (2.34 ± 0.49), (1.54 ± 0.22), (1.53 ± 0.30), (0.80 ± 0.35), (0.76 ± 0.30)°; in group E (0.35 ± 0.12), (0.56 ± 0.34), (0.44 ± 0.15), (0.55 ± 0.16), (0.43 ± 0.07), (0.29 ± 0.06)°. Under the six conditions, there were generally significant differences between group A and other four groups, and between group B and groups C, D and E (P lt; 0.001), and between group E and groups C, D in flexion/ extension and left/right lateral bending (P lt; 0.05). There was no significant difference between group E and groups C, D in left/right axial rotation (P gt; 0.05). Conclusion In vivo biomechanical studies show that ASMG operation has unique superiority in the reconstruction of the atlantoaxial stabil ity, especially in controll ing stabil ity of flexion/extension and left/right lateral bending, and thus it ensures successful fusion of the implanted bone. It is arel iable surgical choice for the treatment of the obsolete instabil ity or dislocation of C1, 2 joint.