Objective To study the feasibility and clinical results of C2, 3 pedicle-lateral mass plate fixation in the treatment of unstable Hangman's fractures. Methods From March 1999 to July 2005, 25 cases of unstable Hangman's fracture were treated surgically using the C2, 3 pedicle-lateral mass plate. All the cases were followed up for the healing of bone and function of the cervical vertebrate. Results The average follow-up period was 38 months. Twenty-three cases had a perfect reduction. Three cases had kyphosis deformity. There were no other complications related to the operation. AH the cases had a perfect early fusion of the C2 pedicle isthmus and long-term stability of C2, 3 intervertebral space. The clinic results were good. Conclusion Since the C2, 3 pedicle-lateral mass fixation can provide immediate reduction and satisfactory biomechanical stability, it is a good device for unstable Hangman s fractures.

BACKGROUND: There are many methods for posterior cruciate ligament (PCL) reconstruction, which is involved in many graft materials, but few studies aim to compare the differences in outcomes of different grafts for PCL reconstruction. OBJECTIVE: To compare the clinical results of arthroscopic PLC reconstruction with bone-patellar tendon-bone (B-PT-B) autograft, B-TP-B allograft and semitendinosus tendon autograft. DESIGN, TIME AND SETTING: A retrospective case analysis was completed in the Department of Orthopedics, Guangzhou General Hospital of Guangzhou Area Military Command of Chinese PLA from January 2000 to September 2005. MATERIALS: Totally 76 patients underwent arthroscopic PLC reconstruction from January 2000 to September 2005, with the use of B-TP-B autograft in 21 patients, B-TP-B allograft in 27 patients, semitendinosus tendon autograft in 28 patients. METHODS: A retrospective analysis was performed in 76 patients underwent arthroscopic PCL reconstruction, with the use of B-TP-B autograft in 21 patients, B-TP-B allograft in 27 patients, semitendinosus tendon autograft in 28 patients. Postoperative body temperature was examined duration hospitalization. The follow-up parameters included International Knee Documentation Committee (IKDC) scores, Lysholm knee joint scores, and KT-1000 evaluation.MAIN OUTCOME MEASURES: ①Range of motion. ②joint stability: posterior draw test and KT-1000 test. ③overall function of knee: IKDC scores and Lysholm scores; ④complications and side effect. RESULTS: The time of follow-up visit was 26-79 months. Differences were no statistically significant among the IKDC scores, Lysholm scores, KT-1000 side-side difference, the positive rate of posterior draw test in three groups of patients with PCL reconstruction using B-TP-B autograft, B-TP-B allograft and semitendinosus tendon graft (P > 0.05); 10° flexion limitation was found in 3 cases of B-TP-B autograft, 5° flexion limitation in 1 case of B-TP-B allograft and flexion limitation in 2 case of semitendinosus tendon graft. There was no significant difference in the ratio of knee joint flexion limitation among three groups. No synarthrophysis, wound infection, implant disrupture, screw loose, patellar fracture or vascular nerve injury was observed in three groups of patients; There were 12 cases presenting anterior knee pain in the B-TP-B autograft group and 5 cases presenting posterior knee pain in the semitendinosus tendon graft group. The difference of peal-knee pain incidence was statistically significant among three groups (P=0), the highest in B-TP-B autograft group, then semitendinosus tendon graft group and the lowest in B-TP-B allograft group. The time of post-operative fever in B-TP-B autograft group was earlier than that in the B-TP-B allograft and semitendinosus tendon graft groups (P=0). There was no significant difference between allogreft group and semitendinosus tendon autograft group (P=0.844). The rejections appeared in 4 cases of B-TP-B allograft with the manifestations of the sustained jam-like liquid outflow from tibial tunnel. After dressing, hormones or indomethacln, the rejection was healed. CONCLUSION: The arthroscopic B-TP-B autograft, B-TP-B autograft and semitendinosus tendon autograft have the same clinical curative effect in PCL reconstruction.

BACKGROUND: Meniscus injury is a common sports injury of knee joint. Severe meniscus injury is difficult for clinical treatment due to the blood supply features. Effective repair of meniscus injury can prevent osteoarthritis of knee joint. OBJECTIVE: To review meniscus injury repair and transplantation replacement treatment of meniscus injury.METHODS: A computer-based online search of CNKI (www.cnki.net) and Medline database (www.pubmed.com) was performed for related articles published between January 2000 and March 2009, with the keywords "meniscus, repair, transplanted replacement therapy" in Chinese and English. Unrelated and repetitive studies were excluded. A total of 29 articles were included.RESULTS AND CONCLUSION: There are a number of treatment for meniscus injury, and indications and appropriate repair methods are very important. Xenogenic meniscus transplantation and tissue-engineered meniscus provide novel approach for meniscus injury repair, in particular the repair of avascular zone. However, the two methods require validation of immunology,epidemiology, anatomy, biomechanics, and clinical effect.

Objective To investigate the clinical results of posterior cruciate ligament (PCL) reconstruction by double bundle-double tunnel Y-shape of the anterior tibialis tendon allograft. Methods From March 2001 to January 2008, 47 patients underwent PCL reconstruction were included. The allogeneic adult anterior tibialis tendon was prepared into the Y-shape double bundles with the length of 130 mm; A bundle was defined as A-side; B-side was two short bundle (B1, B2 bundle). A bundle was 70 mm in length with a diameter of 10-12 mm. B1 bundle (anterolateral bundle) was 55 mm long with a diameter of 6 mm; B2 bundle(posteromedial bundle) was about 50 mm with a diameter of 6 mm. The allograft ligament was installed through the antero-medial approach. Absorbable interface screws were fixed in the tibial tunnel firstly, and then in the femoral tundles. When being fixed, anterolateral bundle was in flexion of 90°, postero-medial bundle was in 30°. Assisted exercise with knee an angle-locked walking aid had continued for 8-10 weeks. Results The average operating time were 45 min. The average follow-up time was 49.5 months. Preoperative Lachmann was positive in all cases while Lachmann was negative in 39 cases, weakly positive in 5 cases, and positive in 4 cases postoperatively. Post-operative KT-1000 testing, Lysholm score and Tegner activity levels has improved significantly compare with the pre-operative ones. Conclusion The double folded bundles of adult anterior tibialis tendon has sufficient length and diameter for posterior cruciate ligament reconstruction with power tension. The methods of ligament passing through the tunnel has improved to ease the procedure.

BACKGROUND: Lateral collateral ligaments play an important role in maintaining knee stability.Motion reduction of knee joint can be realized and the changes laws of medial and lateral collateral ligaments' length after anterior cruciate ligament(ACL)injury during weight-bearing flexion can be obtained via 2D/3D image registration technique.OBJECTIVE: To study in vivo stability of length changes of the medial and lateral collateral ligaments of ACL injury knee during weight-bearing flexion.METHODS: Eight volunteers with unilateral ACL rupture and contralateral normal knees,was captured CT images and 2orthogonal images of the knee at 0,15°,30°,60°,and 90° of weight-bearing flexion.These orthogonal images were used to recreate the in vivo knee positions at each of the targeted flexion angles by the method of 2D/3D image registration.Through the bone insertion of medial and lateral collateral ligaments,the elongation changes of medial and lateral collateral ligaments were obtained.RESULTS AND CONCLUSION: At 0°,15° and 30°,the length of medial collateral ligament of ACL injury knees was longer than normal knees,but the lateral collateral ligaments length of ACL injury knee was shorter than that of normal knees.All the differences have statistical significances(P < 0.05).The findings demonstrated that,at 0°,15° and 30°,the medial collateral ligament length of ACL injury knees was longer than normal knees,but lateral collateral ligaments length of ACL injury knees was shorter than normal knees.

BACKGROUND: The rudiment of tissue engineering is to obtain tissue from patients. The cells are expanded into a population through cellular culture, and seeded into scaffolds, which can accommodate and guide the growth and proliferation of new cells in the three-dimensional scaffolds. At last, the constructed tissue is transplanted in vivo to repair or replace damaged or diseased tissues. Afterward neovascularization of the graft, the scaffolds are absorbed gradually. Finally, the new tissue replaces completely the damaged or diseased tissuesOBJECTIVE: To evaluate the feasibility of designing and fabricating customized anatomical-shaped bone tissue-engineering scaffolds with reverse engineering and rapid prototyping (RP) techniques. To avoid the disadvantage of the conventional fabricated methods of the scaffolds.DESIGN: The method of fabricating customized anatomical-shaped bone tissue engineering scaffolds.SETTING: Computer-aided design (CAD) of the scaffold was conducted in CAD training center, Guangdong Machinery Research Institute. Rapid prototyping fabrication of the scaffold was conducted in Guangdong Longchuangyu Limited Cooperation. The scaffold was fabricated by sterophotocureable technology and was made of photosensitized resin.METHODS: This experiment was carried out at the Center of Department of Traumatic Orthopedics, General Hospital of Guangzhou Military Area Command of Chinese PLA from October 2004 and January 2005. According to reverse engineering, layered image information of skeleton of the patients was scanned with CT/MRI. Anatomical models of region of interesting were created by means of CT or MRI three-dimensional reconstruction and surface reconstruction. The internal construction of the scaffolds was designed with CAD software in the outline of the anatomical models to develop computer-aided model. The prototypes of the scaffolds were fabricated by RP process.MAIN OUTCOME MEASURES: ①CT/MRI scanning, three-dimensional reconstruction, anatomical modeling; ② computer-aided design of customized bone tissue engineering scaffolds; ③rapid prototyping fabrication of customized bone tissue engineering scaffold.RESULTS: ①Anatomical models of bone joint were established through CT/MRI three-dimensional reconstruction. ② The internal structure of the scaffold was designed to establish the entity model of bone tissue engineering scaffold successfully with computer-aided design software. ③ CAD model of bone tissue engineering scaffold guided prototypes to develop the customized anatomical-shaped bone tissue engineering scaffolds. The internal structure of bone tissue engineering scaffold was fine and had high degree of porosity-and pore interconnectivity.CONCLUSION: Customized anatomical-shaped bone tissue engineering scaffolds can be fabricated with reverse engineering and RP technology. Among all RP processes, stereophotocureable technology (SLA) is the best one with good precision, smooth surface and good shaping.

BACKGROUND:C2 transpedicle screw fixation for Hangman fractures has been paid more attention due to reliability and no loss of physiological function.However,there are lacks of biomechanical evidences for indication treatment because the fixation is single segmental.OBJECTIVE:To investigate the biomechanical stability of C2 transpedicle screw fixation for Hangman fractures.DESIGN,TIME and SEITING:This was a contrast study which was performed at the General Key Laboratory of Biomechanics,First Military Medical University of Chinese PLA from May to August 2004.MATERIALS:AO-universal titanium alloy transpedicle screw of 18 25 mm in length and 3.5 mm in diameter was adopted in this study.Six fresh C1-C4 cervical vetebrae samples were ordiually made into type Ⅰ,ⅡA,and Ⅱ Hangman fracture models.METHODS:After transpedicle screw fixation.Hangman fracture models were measured by non-destroyed style with spinal anterior flexion/posterior extension,left/right lateral curvature,and left/right axial direction.Loading/unlonding circulation was performed three times during each testing.Kinematics indicators were measured on the 3rd circulation.MAIN OUTCOME MEASURES:Spinal motor images at zero load and maximal load were obtained with laser photoscanning(0.1% in precision),and the corresponding systematic software was adopted to calculate 3D range of movement.RESULTS:The relative stability of type Ⅰ Hangman fracture models after C2 transpedicle screw fixation was 100.62%(inflexion),96.91%(posterior extension),99.19%(lateral curvature),and 97.12%(rotation)as compared to control group (P＞0.05).The relative stability of type Ⅱ Hangman fracture models after C2 transpedicle screw fixation was 47.84%(inflexion),21.29%(posterior extension),65.98%(lateral curvature),and 41.69%(rotation)as compared to control group (P＜0.05).CONCLUSION:Biochemical evaluation suggests that type Ⅰ and Ⅱ A Hangman fractures do fit for C2 transpedicle screw fixation,and the fixation may generate well physiological fixation or stability.However,stability of type Ⅱ Hangman fracture is poor,so it is not suitably adopted single transpedicle screw fixation.

BACKGROUND:The methods used to repair articular cartilage defects currently have the cons and pros. Fibrocartilages are commonly used to repair tissues, and the fibrocartilage lacks of the tissue biomechanical properties and chemical properties of normal hyaline cartilage. OBJECTIVE:To investigate the feasibility of biological osteochondral xenogenic graft transplantation to repair articular cartilage defects. METHODS:The normal goats were randomly divided into two groups. The donor pig knee joints were the experimental group. Cylindrical osteochondral with the diameter of 4.5 mm and length of 10 mm were col ected with the Smith&Nephew osteochondral transplantation device, and the patented technology was used for deantigen. The donor goat knee joint osteochondrals were the control group and preserved with cryopreservation. The lesions on femoral trochlea and weight-bearing surface of medial condyle were selected respectively for osteochondral implantation, and the animals were sacrificed at 16 and 32 weeks after operation for the general and pathological section observation. RESULTS AND CONCLUSION:General observation in the experimental showed that the lesions were covered by fibroid tissue;some cartilage of the grafts turned yel ow and there was clear boundary between the surface and the peripheral cartilages;the general and section observation under microscope showed that lesions of the control group were covered by the grafts basical y, and cracks could be seen on the edge of the transplant part. The results show that there is difference between effects of biological osteochondral xenogenic graft transplantation and osteochondral al ograft transplantation for the repairing of articular cartilage defects, and osteochondral al ograft transplantation bas better effect.

Objective To study the feasibility and early efficacy of matrix?induced autologous chondrocyte implantation repairing knee joint cartilage injury. Methods The Matrix?induced autologous chondrocyte implantation was used to repair knee joint cartilage injury in 13 cases (11 males and 2 females) with knee joint cartilage injury from April 2012 to March 2013. The av?erage age was 27.5 years old. All cases were suffering from unilateral focal cartilage defect of knee joint with International Carti?lage Repair Society (ICRS) chondral defect classification system grade III or IV, visual analogue scale (VAS)>3, and all of which had corresponding pain symptoms. The average defect area was 4.2 cm2. Standardized rehabilitation exercise was carried out after matrix?induced autologous chondrocyte implantation. Patients were followed up for 1 years, and knee injury and use osteoarthritis outcome score(KOOS), International Knee Documentation Committee (IKDC), subjective knee form and Lysholm score were col?lected to assess the function. Meanwhile, magnetic resonance observation of cartilage repair tissue (MOCART) score was used to assess the magnetic resonance imaging. Results All patients had been followed?up for 1 year. One patient had meniscus repair under arthroscopy for the meniscus injury caused by downstairs sprain in 6.5 months postoperative, so the score of 12 months post?operative was excluded. The knee range of motion was decreased in 3 months postoperative (123.1°±8.0°) compared to preopera?tive one (135.4°±5.7°), and has no difference in 6 months (136.1°±6.1°) and 12 months postoperative (135.1°±3.6°) compared to preoperative one. The 5 subsets of KOOS score were decreased in 3 months compared to preoperative one, and were significantly increased in 6 months and 12 months. The IKDC has no difference in 3 months (26.1±3.9) compared to preoperative one (43.5± 6.5), and were significantly increased in 6 months (53.3±5.8) and 12 months (62.8±7.2) compared to preoperative one. The magnet?ic resonance observation of cartilage repair tissue (MOCART) score was increased in 12 month(73.3±17.9)compared to preopera?tive one(51.5 ± 12.6). Conclusion MACI is a good technology for knee joint cartilage injury. It has a good clinical effect on re? pairing cartilage injury effectively and restoring the function of knee joint.

Anterior knee pain continues to be a major problem following total knee arthroplasty (TKA). Patellofemoral joint is closely associated to the occurrence of the anterior knee pain, so it is also called patellofemoral joint pain. Overstuff of patellofemoral joint and patella maltracking are the main factors for anterior part of the post-operative pain. They are resulted from the change of native morphology and Q angle of patellofemoral joint after operation. Instead of non-modifiable patients' congenital and genetic factors, they are mainly related to the improper surgical techniques and the mismatch between prostheses and native patellofemoral morphology. The reason of the mismatch is that the prosthesis is unable to cover all kinds of differences of the patellofemoral morphology among races and genders. In addition, some surgical techniques, including patellar replacement, circumpatellar denervation, femoral and patellar prostheses location, and the selection of the type of prosthesis, also affect the occurrence of anterior knee pain. The above mentioned factors may eventually lead to excessive and uneven distribution of the patella-femoral loads, which would compress and simulate the peripheral nerves around the joint. Ultimately, they result in the anterior knee pain. Therefore, the following effective strategies could lead to relief anterior knee pain and improve patients overall satisfaction after TKA, including improvements of prostheses design, patellar resurfacing, circumpatellar denervation, infrapatellar fat padpreservation or using mobile-bearing rotating-platform.