ABSTRACT
The artificial joints containing metal prosthetic components have different degrees of wear particles in the human body,which is the main reason for local osteolysis,inflammatory pseudotumor and prosthesis loosening.The metal wear debris after ar-tificial joint replacement can be derived from the normal wear of the weight-bearing interface volume,or from the edge wear of the non-weight-bearing interface.The particles produced by joint wear are mainly nano-sized particles,and their toxicity is stronger than that of micro-sized particles and ions.The wear particles can cause either local reactions by local accumulation or toxicity symptoms of multiple systems by entering the blood in various forms.Cobalt has the strongest toxicity among various metal particles.Oxidative stress,hyper-sensitivity,endoplasmic reticulum stress,autophagy,and direct destruction are the possible cytotoxic and genotoxic mechanisms,and the corresponding detoxification studies are also related to these mechanisms.There is no definite standard for the increase of the con-centration of metal particles and the clinical symptoms.At present, the main treatment is to remove the prosthesis and symptomatic treatment.Future research will focus on the improvement of prosthetic materials and finding new alternative treatment for joint diseases. Basic research will further explore the mechanism of toxicity of metal particles,especially the discovery of signal pathways and suscepti-bility genes as well as the in vivo and in vitro studies and clinical trials of new antidote.
ABSTRACT
Objective:To investigate the method of arthroplasty for reconstructing femporomandibular joint (TMJ) after the establishment of TMJ articular defect models in the rabbits,and to clarify the replacement and repair effects of carboh fiber reinforced polyetheretherketone (CFR-PEEK) material TMJ prostheses,and to provide an experimental basis for the clinical application of CFR-PEEK artificial joints to replace TMJ.Methods:Thirteen healthy adult Japanese rabbits were randomly divided into experimental group (n=6),positive control group (n=4) and negative control group (n =3).The right TMJ articular process of the rabbits in experimental group were resected to establish the joint defect models,and then the CFR-PEEK artificial joints were impanted.The right TMJ articular process of the rabbits in positive control group were resected,and the joint defect models were established without the CFR-PEEK artificial joint implantation.The rabbits in negative control group didn't receive any treatment.The body weights of the rabbits in each group were measured in 13 weeks.The effects of fixation and replacement after artificial joint implantation were assessed by CT imaging.Results:The TMJ articular process defect model was successfully implanted with the CFR-PEEK artificial joint.The CT imaging results after threedimensional reconstruction and CT images by contrast in vitro showed that the CFR-PEEK-implanted artificial joint was fixed well,it could be instead of the normal joint function.Compared with positive control group,the weights of rabbits in experimental group were significantly increased (P＜ 0.05) at 13 weeks;compared with positive control group,the weights of rabbits in experimental group and negative control group were both significantly increased (P＞0.05) at 13 weeks,but there was no significant difference between them (P＞0.05).The weights of rabbits in experimental group and negative control group kept normal growth;the weights of rabbits in positive control group was increased slowly,and even stopped growing or was negative.Conclusion:The CFR-PEEK artificial joint can be successfully implanted into the TMJ defect model and be used to repair the defect which help to restore chewing function.The CFR-PEEK is expected to be an ideal material for reconstructing TMJ.
ABSTRACT
Objective:To investigate the method of arthroplasty for reconstructing femporomandibular joint (TMJ) after the establishment of TMJ articular defect models in the rabbits,and to clarify the replacement and repair effects of carboh fiber reinforced polyetheretherketone (CFR-PEEK) material TMJ prostheses,and to provide an experimental basis for the clinical application of CFR-PEEK artificial joints to replace TMJ.Methods:Thirteen healthy adult Japanese rabbits were randomly divided into experimental group (n=6),positive control group (n=4) and negative control group (n =3).The right TMJ articular process of the rabbits in experimental group were resected to establish the joint defect models,and then the CFR-PEEK artificial joints were impanted.The right TMJ articular process of the rabbits in positive control group were resected,and the joint defect models were established without the CFR-PEEK artificial joint implantation.The rabbits in negative control group didn't receive any treatment.The body weights of the rabbits in each group were measured in 13 weeks.The effects of fixation and replacement after artificial joint implantation were assessed by CT imaging.Results:The TMJ articular process defect model was successfully implanted with the CFR-PEEK artificial joint.The CT imaging results after threedimensional reconstruction and CT images by contrast in vitro showed that the CFR-PEEK-implanted artificial joint was fixed well,it could be instead of the normal joint function.Compared with positive control group,the weights of rabbits in experimental group were significantly increased (P＜ 0.05) at 13 weeks;compared with positive control group,the weights of rabbits in experimental group and negative control group were both significantly increased (P＞0.05) at 13 weeks,but there was no significant difference between them (P＞0.05).The weights of rabbits in experimental group and negative control group kept normal growth;the weights of rabbits in positive control group was increased slowly,and even stopped growing or was negative.Conclusion:The CFR-PEEK artificial joint can be successfully implanted into the TMJ defect model and be used to repair the defect which help to restore chewing function.The CFR-PEEK is expected to be an ideal material for reconstructing TMJ.
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ObjectiveTo investigate the treatment efficacy of traumatic proximal interphalangeal (PIP)joint defects with prosthetic replacement.MethodsFrom September 2007 to November 2010, ten patients with joint defect injuries were treated by joint prosthetic replacement (5 index fingers,4 middle fingers,and 1 ring finger),including a reconstructed middle finger.Joint motion range and postoperative pain of all cases were measured to evaluate the treatment.ResultsAll cases went through a smooth operation with primary wound healing,and with neither intraoperative nor postoperative complications happened.The follow-up period was range from 8 months to 2 years.The active motion arcs of PIP joints ranged from 50° to 80°,and satisfactory appearances as well. According to assessment standard of upper extremity described by Chinese Hand Surgery Association,the treatment outcome were excellent in 6 fingers,good in 3 fingers,general in 1 finger.ConclusionJoint prosthetic replacement is a new effective method to treat traumatic proximal interphalangeal joint defect,which is a simple operation with advantages of little trauma and rapid recovery.
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[Objective]To seek for a method to rebuild radial head for comminuted radial head fractures,and recommend a new technique of bipolar radial head replacement.[Method]Five patients with fresh comminuted radial head fractures were treated by Tornier cement stem and bipolar radial prothesis.Among them,three were females and two were males,with the average age of 37.4Y(29-48Y).Four cases were to Mason type Ⅲ and one Mason type Ⅳ.All the patients underwent operation within 3-11 days with an average of 6 days after injury.Rehabilitation began in Mason type Ⅲ radial head fracture patients 48 h postoperatively.Both medial and lateral ligaments were repaired in one case of Mason type Ⅳ fracture.Plastic brace were used for 3 weeks during functional rehabilitation.The postoperative elbow joint was evaluated clinically by Broberg and Morrey score.[Result]All the patients healed by first intention were followed up for 7 to 50 months,with an average of 30 months.According to elbow functional evaluation criteria by Broberg and Morrey scores,there were excellent results in three and good in two respectively with an average of 92.2 points.[Conclusion]Cement stem and bipolar radial head prothesis replacement is a good technique for treating comminuted radial head fractures because it meets the designing principle of modern orthopaedics.
ABSTRACT
Heartening advances continue to be made in numerous research areas of orthopedic biomechanics. Recently, orthopedic research has been greatly expanded, ranging from the cellular level to the whole body level. One of the most important research focuses is a probe into the relationship between biology and mechanics. Emerging information about genetic basis of bone and cartilage pathology is used to provide insight into the fundamental mechanism of common conditions, such as osteoporosis and degenerative arthritis. Other ardent areas of investigation include tissue engineering, biomaterials, tendon healing, and biomechanical properties of tissue at the microscopic level. Interdisciplinary research currently affords a partly unrealized potential to relate the mechanical environment to biological responsiveness. New approaches include iterative computational modeling allowing model parameters at the microscopic level, micro- mechanics, and relatively long- term in vivo manipulation of the mechanical environment. The field of orthopedic biomechanics is widely researched and has led to improved surgical procedures in such areas as bone grafting, joint replacement, and limb supports.