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BACKGROUND: Meniscus cartilage injury is a most common injury of knee joint. In the past decade, stem cell based therapies have been widely applied, and the related studies have been increased rapidly. Pluripotent stem cells have been shown to exist in the meniscus, which may play a key role in the healing of meniscus. OBJECTIVE: To determine the source and culture conditions of stem cells related to tissue-engineered meniscus, and to understand the current development status of tissue- engineered meniscus. METHODS: PubMed, Embase, EBSCO, Cochrane library, and Clinical library databases were retrieved for relevant articles published between 2009 and 2019. The articles concerning tissue-engineered meniscus and selection of seed cells were selected, and finally 64 eligible articles were included for analysis. RESULTS AND CONCLUSION: Stem cells have been extensively used as seed cells in tissue-engineered meniscus due to its high proliferation ability and multipotent property. These cells can effectively repair the meniscus in animals, but the clinical outcomes still remain unclear. Therefore, there is a certain distance from basic research to clinical application. [ABSTRACT FROM AUTHOR]

BACKGROUND: The pathogenesis of osteoarthritis is unknown, and there is no effective treatment. Selecting appropriate animal models will create a good condition for animal experiments on osteoarthritis. OBJECTIVE: To review different experimental animals of osteoarthritis and different modeling methods. METHODS: CNKI, WanFang, VIP and PubMed databases were searched for the articles published from January 2013 to July 2018. The keywords were 'osteoarthritis, models, animals, mice, rats, goats, guinea pigs, sheep" in Chinese and English, respectively. The repetitive articles were excluded, and the articles related to osteoarthritis and animal models were selected for summary and result analysis. RESULTS AND CONCLUSION: Mice, rats, guinea pigs, rabbits, dogs, sheep and other animals can be used as animal models for osteoarthritis research. When studying animal models of osteoarthritis, it is important to choose the right animal models and construction methods. Non-surgical models will not make damage to the parts except for joints, which is in accordance with the pathological process of osteoarthritis. But it is difficult to control, thus causing errors, and it cannot simulate traumatic changes. Surgical models induce joint injury by tissue damage, which exhibits advantages in rapid disease progress and obvious outcomes. Therefore, surgical models are optimal choice for short-term experiments. Different experimental animals and modeling schemes have their own advantages and disadvantages, which need to be reasonably selected according to the requirements of experiments. [ABSTRACT FROM AUTHOR]

Objective: To compare the effectiveness of open reduction of posterior cruciate ligament (PCL) avulsion fracture at tibial insertion of knee joint with absorbable screws fixation and absorbable screw combined with suture anchor fixation., Methods: The clinical data of 26 patients with PCL avulsion fracture at tibial insertion who met the selection criteria between March 2015 and October 2021 were retrospectively analyzed. Among them, 14 patients were fixed with simple absorbable screw (group A), and 12 patients were fixed with absorbable screw combined with suture anchors (group B). All patients were confirmed by X-ray film, CT, or MRI preoperatively, and got positive results in preoperative posterior drawer tests. There was no significant difference in gender, age, side of affected limb, time from injury to operation, comorbidities, and preoperative Meyers & McKeever classification, Lysholm score, and International Knee Documentation Committee (IKDC) score between the two groups ( P >0.05). The operation time and postoperative complications were recorded and compared between the two groups. At last follow-up, Lysholm score and IKDC score were used to evaluate the improvement of knee function., Results: There was no significant difference in operation time between the two groups ( P >0.05). All incisions healed by first intention, and no complication such as vascular and nerve injury or venous thrombosis occurred. All 26 patients were followed up 9-89 months, with an average of 55.3 months. The follow-up time of group A and group B was (55.7±23.2) and (56.8±29.3) months, respectively, with no significant difference ( t =-0.106, P =0.916). Radiographs showed bone healing in both groups at 3 months after operation, and no complication such as infection and traumatic arthritis occurred. At last follow-up, the posterior drawer test was negative in both groups, and the Lysholm score and IKDC score significantly improved when compared with the pre-operative values ( P <0.05). However, there was no significant difference in the improvement value between the two groups ( P >0.05)., Conclusion: For PCL avulsion fracture at tibial insertion of the knee joint, the open reduction and absorbable screw combined with suture anchor fixation can achieve reliable fracture reduction and fixation, which is conducive to the early rehabilitation and functional exercise, and the postoperative functional recovery of the knee joint is satisfactory.

Objective: To investigate the effectiveness of double-bundle anterior cruciate ligament (ACL) reconstruction combined with anterolateral ligament (ALL) reconstruction in the treatment of revision patients with ACL graft failure., Methods: Between January 2018 and June 2019, 15 patients underwent ACL revision with double-bundle ACL reconstruction combined with ALL reconstruction. There were 12 males and 3 females with an average age of 30.1 years (range, 17-49 years). The technique of primary ACL reconstruction included single-bundle reconstruction in 13 cases and double-bundle reconstruction in 2 cases. These reconstructions applied autografts in 14 cases and allograft in 1 case. The causes of ACL reconstruction failure were identified as traumatic rupture in 9 cases and non-traumatic failure in 6 cases, including 2 cases of graft absorption and 3 cases of graft laxity. The average time from the primary ACL reconstruction to revision was 28.5 months (range, 8-60 months). The subjective and objective indicators of knee joint function were compared before operation and at last follow-up to evaluate the effectiveness. The subjective indicators included International Knee Documentation Committee (IKDC) score, Lysholm score, and Tegner score. The objective indicators included anterior tibial translation (dynamic and static) and side-to-side difference (SSD), pivot-shift test, Lachman test, the difference of single-legged hop test, and the loss ratio of extensor muscle strength on the affected side., Results: All incisions healed by first intetion, and no complications such as infection, venous thrombosis of lower extremity, or neurovascular injury occurred. All patients were followed up for an average of 19.1 months (range, 12-30 months). At last follow-up, all patients had returned to pre-injury sports level. The IKDC score, Lysholm score, and Tegner score were significantly improved ( P <0.05); anterior tibial translations (dynamic and static) significantly decreased when compared with preoperative one ( P <0.05) and returned to the physiological range. The SSD, Lachman test, pivot-shift test, the difference of single-legged hop test, and the loss ratio of extensor muscle strength on the affected side were significantly better than those before operation ( P <0.05).During the follow-up, there was no re-rupture of the graft, no stiffness of the knee joint and limitation of mobility; 1 case had a protruding femoral end compression screw, which was removed through the original incision under local anesthesia., Conclusion: Double-bundle ACL reconstruction combined with ALL reconstruction can significantly improve the knee function in revision patients with ACL graft failure. It can reduce the anterior translation of tibia, and effectively prevent postoperative rotational instability of the knee.

Objective: To investigate the effectiveness of modified patellar tendon reconstruction using hamstring autograft in the treatment of chronic patellar tendon rupture and defects., Methods: The clinical data of 11 patients with chronic patellar tendon rupture and defects admitted between January 2015 and August 2018 were retrospectively analyzed. The patient were treated with inverted U-shaped reconstruction technique using hamstring autografts, in which 2 bone tunnels were created at the level of 1/2 and lower 3/4 of the patella, and 1 bone tunnel was created beneath the tibial tuberosity. There were 8 males and 3 females with an average age of 30.1 years (range, 10-61 years). The average interval from the primary injury to the operation was 9.5 months (range, 2-36 months). According to Yousef classification, there were 7 cases of type A2, 3 cases of type B2, and 1 case of type C2. The length of the patella tendon defect was measured when the patella was reducted intraoperatively with an average of 4.5 cm (range, 2.7-7.1 cm). Subjective function scores [including International Knee Documentation Committee (IKDC) subjective score, Tegner activity level, and Lysholm score] were evaluated before operation and at last follow-up. The loss of knee extension, Caton index, and thigh circumference difference at 15 cm above the patella between bilateral limbs were also measured., Results: All patients were followed up 24-66 months (mean, 34.2 months). All incisions were primary healing, and there were no complications such as wound infection, venous thrombosis of the lower extremities, stiffness of the knee joint, graft failure, neurovascular injury, etc . No second revision surgery was performed during the follow-up. At last follow-up, the subjective function scores (IKDC subjective score, Tegner activity level, Lysholm score), loss of knee extension, thigh circumference difference, and Caton index were significantly improved when compared with those before operation ( P <0.05). Two patients still had patella alta, with Caton indexes of 1.29 and 1.32, respectively., Conclusion: In the treatment of chronic patellar tendon ruptures and defects, the modified patellar tendon reconstruction using hamstring autograft can significantly improve the postoperative knee function, restore the normal range of knee extension, enhance the extensor and correct the patella alta.

Objective: To review research progress in the anterolateral ligament (ALL) of knee, and provide a clinical reference for diagnosis and treatment of ALL injury., Methods: The literature on the diagnosis and treatment of ALL injury was widely reviewed. The incidence, anatomy, biomechanics, injury mechanism, and treatment status of ALL were summarized., Results: The ALL contributes to the effect of controlling the internal rotation and anterior translation of the tibia, which affects the axial migration of the knee. ALL injury can be diagnosed according to the signs and MRI examination. Currently, no consensus exists for the surgical indications of ALL injury, but most surgeons tend to perform ALL reconstruction in patients requiring anterior cruciate ligament (ACL) reconstruction or revision surgery with higher pivot-shift tests. At present, various techniques have been used for ALL reconstruction, and there is no optimal technique. In addition, the long-term effectiveness of ALL reconstruction is unclear due to the lack of high-quality studies and long-term postoperative follow-up., Conclusion: The ALL contributes to maintaining knee stability, and the ALL reconstruction technique and its effectiveness still need further research.

Objective: To summarize and analyze the research progress of scaffold materials used in tissue engineered meniscus., Methods: The classification and bionics design of scaffold materials were summarized by consulting domestic and foreign literature related to the research of tissue engineered meniscus in recent years., Results: Tissue engineered meniscus scaffolds can be roughly classified into synthetic polymers, hydrogels, extracellular matrix components, and tissue derived materials. These different materials have different characteristics, so the use of a single material has its unique disadvantages, and the use of a variety of materials composite scaffolds can learn from each other, which is a hot research area at present. In addition to material selection, material processing methods are also the focus of research. At the same time, according to the morphological structure and mechanical characteristics of the meniscus, the bionic design of tissue engineered meniscus scaffolds has great potential., Conclusion: At present, there are many kinds of scaffold materials for tissue engineered meniscus. However, there is no material that can completely simulate the natural meniscus, and further research of scaffold materials is still needed.

Objective: To summarize the research progress of rehabilitation after autologous chondrocyte implantation (ACI)., Methods: The literature related to basic science and clinical practice about rehabilitation after ACI in recent years was searched, selected, and analyzed., Results: Based on the included literature, the progress of the graft maturation consists of proliferation phase (0-6 weeks), transition phase (6-12 weeks), remodeling phase (12-26 weeks), and maturation phase (26 weeks-2 years). To achieve early protection, stimulate the maturation, and promote the graft-bone integrity, rehabilitation protocol ought to be based on the biomechanical properties at different phases. Weight-bearing program, range of motion (ROM), and options or facilities of exercise are importance when considering a rehabilitation program., Conclusion: It has been proved that the patients need a program with an increasingly progressive weight-bearing and ROM in principles of rehabilitation after ACI. Specific facilities can be taken at a certain phase. Evidences extracted in the present work are rather low and the high-quality and controlled trials still need to improve the rehabilitation protocol.

Objective: To investigate effectiveness of rotator cuff repair with manipulation release and arthroscopic debridement for rotator cuff tear with shoulder stiffness., Methods: A retrospectively study was performed on the data of 15 patients with rotator cuff tear combined with shoulder stiffness (stiff group) and 24 patients without stiffness (non-stiff group) between January 2014 and December 2015. The patients in the stiff group underwent arthroscopic rotator cuff repair with manipulation release and arthroscopic debridement while the patients in the non-stiff group only received arthroscopic rotator cuff repair. The patients in the stiff group were older than the patients in the non-stiff group, showing significant difference ( P <0.05). There was no significant difference in gender, type of rotator cuff tear, side of rotator cuff tear, and combined with diabetes between 2 groups ( P >0.05). The visual analogue scale (VAS) score, University of California Los Angeles (UCLA) score, American Shoulder and Elbow Surgeons (ASES) score, and range of motion (ROM) were used to evaluate the effectiveness after operation., Results: All incisions healed by first intention without any complication after operation. The patients were followed up 13-31 months in the stiff group (mean, 19.2 months) and 13-23 months in the non-stiff group (mean, 20.3 months). There was no significant difference in follow- up time between 2 groups ( t =-0.573, P =0.570). The VAS score in the stiff group was higher than that in the non-stiff group before operation ( t =-2.166, P =0.037); there was no significant difference between 2 groups at 3, 6, 12 months and last follow-up ( P >0.05). The forward flexion and external rotation were significantly lower in the stiff group than those in the non-stiff group before operation and at 3 months after operation ( P <0.05); there was no significant difference between 2 groups at 6, 12 months and last follow-up ( P >0.05). At last follow-up, the internal rotation was beyond L 3 level in 2 groups. The preoperative UCLA score was significant lower in the stiff group than that in the non-stiff group ( P =0.037); but there was no significant difference in UCLA score at last follow-up between 2 groups ( P =0.786). There was no significant difference in pre- and post-operative ASES scores between 2 groups ( P >0.05)., Conclusion: Satisfactory effectiveness can be achieved in the patients with rotator cuff tear combined with shoulder stiffness after rotator cuff repair with manipulation release and arthroscopic debridement, although the patients with shoulder stiffness had slower postoperative recovery of ROM until 6 months after operation.

Objective: To investigate the effectiveness of individual surgery for chronic Achilles tendon rupture., Methods: A retrospective analysis was made on the clinical data of 25 patients (26 Achilles tendons) with chronic Achilles tendon rupture between September 2009 and March 2016, including 22 males and 3 females with a mean age of 38 years (range,18-59 years). The median disease duration was 12 weeks (range, 4 weeks to 12 years). The repairing method depended on the defect size, injury site, and tissue condition of the involved Achilles tendon: 9 Achilles tendons were repaired by end-to-end anastomosis, 8 by a gastrocnemius turndown flap, and 9 by auto free tendon (4 ipsilateral hamstring tendon and 5 ipsilateral 2/3 peroneus longus tendon). The American Orthopedic Foot and Ankle Society (AOFAS) ankle-hind foot score, heel lifting of the affected leg, active ankle range of motion (plantar flexion and dorsiflexion), maximum calf circumference, and complications were applied to assess the effectiveness., Results: Hypersensitivity occurred in 1 incision, and stage I healing was obtained in the other incisions. No complication of re-rupture, infection, nerve injury, or deep venous thrombosis occurred. All the patients were followed up 8-85 months (mean, 34 months). The AOFAS ankle-hind foot score was significantly improved to 95.81±5.34 at last follow-up from preoperative 50.54±5.52 ( t =-34.844, P =0.000); the excellent and good rate was 100% (excellent in 21 cases and good in 4 cases). The active dorsiflexion of the operated side [(13.9±2.4)°] was significantly lower than that of normal side [(16.7±2.0)°] ( t =-9.099, P =0.000), but the active plantar flexion showed no significant difference between affected side [(39.8± 3.2)°] and normal side [(40.6±2.6°)] ( t =-1.917, P =0.068). The maximum calf circumference of the operated side [(379.4±18.8) mm] was significantly lower than that of normal side [(387.1±16.6) cm] ( t =-5.053, P =0.000). The other patients could finish heel lifting of the affected leg without limitation except for 1 patient. All patients returned to normal work and activity, and 12 patients returned to normal sports., Conclusion: Individual surgery depending on the defect, injury site, and tissue condition of the involved Achilles tendon can repair all kinds of chronic Achilles tendon rupture with a low rate of complications.

Objective: To investigate the methods and the effectiveness of arthroscopic treatment combined with repair of the cyst wall using the tendon flap of medial head of gastrocnemius muscle after resection of popliteal cyst., Methods: A retrospective analysis was made on the clinical data of 140 patients with popliteal cyst between August 2009 and June 2014, including 44 males and 96 females with a mean age of 54.68 years (range, 14-80 years). The median course of symptoms was 31 months (range, 20 days to 30 years). According to Rauschning and Lindgren criteria for popliteal cyst grade, 4 cases were rated as grade I, 44 cases as grade II, and 92 cases as grade III. The preoperative Lysholm knee score was 68.99 ± 8.23. Firstly, cyst was resected, then the hernia sac of joint capsule was repaired with the tendon flap of medial head of gastrocnemius muscle, and finally a knee arthroscopy was used for the diagnosis and treatment of intra-articular lesions., Results: No complication of nerve or blood vessel injury, infection, or necrosis occurred. The mean follow-up was 26 months (range, 6-64 months). During follow-up, 1 case (0.71%) had cyst recurrence. According to Rauschning and Lindgren criteria for popliteal cyst grade, 37 cases were rated as grade 0, 92 cases as grade I, 10 cases as grade II, and 1 case as grade III at 6 months after operation, showing significant difference when compared with preoperative one (Z = -14.303, P = 0.000); the Lysholm knee score (85.51 ± 9.23) was significantly higher than preoperative score (t= -15.798, P = 0.000)., Conclusion: Arthroscopic treatment combined with repair of the cyst wall with the tendon flap of medial head of gastrocnemius muscle after resection of popliteal cyst is a better way to avoid recurrence.

Objective: To investigate the risk factors associated with meniscus and cartilage lesions concomitant with isolated rupture of posterior cruciate ligament (PCL).
, Methods: A total of 147 patients with rupture of PCL from January, 2005 to June, 2013 were retrospectively analyzed for associations of distribution, incidence of meniscal tears or cartilage injuries with gender, age, sides, duration, body mass index, cause or degree of instability.
, Results: Incidence for meniscal injuries was 14.3%, which was statistically different among groups in gender, age, sides, duration and degree of instability (P<0.05). Chondral lesions were mainly appeared in medial tibiofemoral compartment and patellofemoral compartment, and the incidence was statistically different among groups in gender, age, duration, and degree of instability (P<0.05). No independent risk factor was found to be associated with meniscal and chondral injuries.
, Conclusion: Severe cartilage lesions and less meniscal tears can be induced by the rupture of PCL. Medical treatment at the early stage is necessary to restore stability and reduce chondral injuries.

Objective: To research the effect of recombinant adenovirus-bone morphogenetic protein 12 (Ad-BMP-12) transfection on the differentiation of peripheral blood mesenchymal stem cells (MSCs) into tendon/ligament cells., Methods: Peripheral blood MSCs were isolated from New Zealand rabbits (3-4 months old) and cultured in vitro until passage 3. The recombinant adenoviral vector system was prepared using AdEasy system, then transfected into MSCs at passage 3 (transfected group); untransfected MSCs served as control (untransfected group). The morphological characteristics and growth of transfected cells were observed under inverted phase contrast microscope. The transfection efficiency and green fluorescent protein (GFP) expression were detected by flow cytometry (FCM) and fluorescence microscopy. After cultured for 14 days in vitro, the expressions of tendon/ligament-specific markers were determined by immunohistochemistry and real-time fluorescent quantitative PCR., Results: GFP expression could be observed in peripheral blood MSCs at 8 hours after transfection. At 24 hours after transfection, the cells had clear morphology and grew slowly under inverted phase contrast microscope and almost all expressed GFP at the same field under fluorescence microscopy. FCM analysis showed that the transfection efficiency of the transfected group was 99.57%, while it was 2.46% in the untransfected group. The immunohistochemistry showed that the expression of collagen type I gradually increased with culture time in vitro. Real-time fluorescent quantitative PCR results showed that the mRNA expressions of the tendon/ligament-specific genes (Tenomodulin, Tenascin-C, and Decorin) in the transfected group were significantly higher than those in untransfected group (0.061+/- 0.013 vs. 0.004 +/- 0.002, t = -7.700, P=0.031; 0.029 +/- 0.008 vs. 0.003 +/- 0.001, t = -5.741, P=0.020; 0.679 +/- 0.067 vs. 0.142 +/- 0.024, t = -12.998, P=0.000)., Conclusion: Ad-BMP-12 can significantly promote differentiation of peripheral blood MSCs into tendon/ligament fibroblasts and enhance the expressions of tendon/ligament-specific phenotypic differentiation, which would provide the evidence for peripheral blood MSCs applied for tendon/ligament regeneration.

Objective: To review the research progress of the preparation and components of the platelet rich plasma (PRP)., Methods: The recent literature concerning the biological mechanism, preparation, and components of PRP was analyzed and summarized., Results: The biological function of PRP depends on a series of intricate cascade of cellular and molecular events. PRP contains different concentrations of platelets, which would release a large number of the activated molecules, and also contains a small amount of white blood cells and red blood cells. The preparation of PRP is based on platelet concentration. Different preparation techniques would lead to different platelet concentrations, recovery ratios, and components., Conclusion: There is no uniform standard for the preparation of PRP. Different preparation methods and technical parameters of PRP will get different components and different concentrations of PRP, which also provide a reference for clinicians to select the most appropriate PRP for individual patient.

Objective: To summarize the application status and progress of platelet-rich plasma (PRP) in clinical orthopedics., Methods: The recent related literature concerning the application of PRP in clinical orthopedics was extensively reviewed and analyzed., Results: Recently, a large number of clinical studies on PRP have been carried out, which are applied in bone defects or nonunion, spinal fusion, osteoarthritis and cartilage injuries, ligament reconstruction, muscle strain, tendon terminal diseases, and a variety of acute and chronic soft tissue injuries. Some results show certain effectiveness, while others demonstrate invalid., Conclusion: Easily drawing, achieving autologous transplantation, and the biological repair potential of the musculoskeletal tissues make PRP to be widely used in clinical orthopedics. However, there are still no uniform standards accepted and reliable clinical guidelines about the application of PRP. Furthermore, a variety of PRP products and their respective indications are also different. The clinical evidences with the greater sample size and higher quality are still needed to further support the safety and effectiveness of PRP in clinical orthopedics.

Objective: To investigate the effectiveness of open reduction by mini incision and absorbable screw internal fixation for the treatment of anterior cruciate ligament (ACL) tibial eminence avulsion fracture., Methods: Between January 2006 and July 2012, 90 patients (90 knees) with ACL tibial eminence avulsion fracture were treated. There were 58 males and 32 females, aged from 10 to 58 years with an average of 33.7 years. The causes of injury were traffic accident injury in 60 cases, sports injury in 22 cases, and fallinginjury in 8 cases. The disease duration was 1-365 days with a median of 106 days. Combined injuries included 14 cases of meniscus injury, 5 cases of medial collateral ligament injury, and 3 cases of avulsion fracture of the anterior horn of the lateral meniscus. All patients underwent open reduction by mini incision and internal fixation with absorbable screw. Postoperative rehabilitation exercise was performed., Results: Two patients had delayed healing of incision, and others obtained primary healing. All the patients were followed up 6-72 months (mean, 40.1 months). X-ray examination showed that bone union was achieved in all patients at 3-12 months after operation; nail tail came off in 7 cases at 4-13 months after operation, and the nail tail was taken out under arthroscopy. At 6-12 months after operation, the range of motion (ROM), Tegner score, Lysholm score, and International Knee Documentation Committee (IKDC) score were significantly increased when compared with preoperative ones (P < 0.05)., Conclusion: A combination of open reduction by mini incision and absorbable screw internal fixation for the treatment of ACL tibial eminence avulsion fracture has the advantages of easy operation, firm fixation, and satisfactory functional rehabilitation, so it is a safe and effective method for the treatment of ACL tibial eminence avulsion fracture.

Objective: To review the research progress of the co-culture system for constructing vascularized tissue engineered bone., Methods: The recent literature concerning the co-culture system for constructing vascularized tissue engineered bone was reviewed, including the selection of osteogenic and endothelial lineages, the design and surface modification of scaffolds, the models and dimensions of the co-culture system, the mechanism, the culture conditions, and their application progress., Results: The construction of vascularized tissue engineered bone is the prerequisite for their survival and further clinical application in vivo. Mesenchymal stem cells (owning the excellent osteogenic potential) and endothelial progenitor cells (capable of directional differentiation into endothelial cell) are considered as attractive cell types for the co-culture system to construct vascularized tissue engineered bone. The culture conditions need to be further optimized. Furthermore, how to achieve the clinical goals of minimal invasion and autologous transplantation also need to be further studied., Conclusion: The strategy of the co-culture system for constructing vascularized tissue engineered bone would have a very broad prospects for clinical application in future.

Objective: To review the research progress of the seed cells, scaffolds, growth factors, and the prospects for clinical application of the intervertebral disc regeneration., Methods: The recent literature concerning the regeneration strategies and tissue engineering for treatment of degenerative intervertebral disc disease was extensively reviewed and summarized., Results: Seed cells based on mesenchymal stem cells (MSCs) and multiple-designed biomimetic scaffolds are the hot topic in the field of intervertebral disc regeneration. It needs to be further investigated how to effectively combine the interactions of seed cells, scaffolds, and growth factors and to play their regulation function., Conclusion: The biological regeneration of intervertebral disc would have a very broad prospects for clinical application in future.

Tissue engineered meniscus provides a novel approach for the treatment of severe meniscus injury. The researches on scaffold for tissue engineered meniscus is an essential element. The researches on scaffolds for tissue engineered meniscus, including natural biomaterials and synthetic polymer, have made great advances in recent years. At present, collagen meniscus implants have been used in clinical practice. As hydrogel is characterized by having high water content and good biocompatibility, being similar to extracellular matrix in structure, and being able to provide access to microsurgery, it has become the hotspot field in recent years. Meanwhile, the combinatorial scaffold material advantages of biological composite tissue engineered scaffolds also illuminate the key point of research on meniscal scaffolds. This paper reviews the recent progress in betterment of the scaffolds so as to provide a theoretical and practical basis for further researches of tissue engineered meniscus.

Objective: To investigate the method and the short term clinical effectiveness of in situ suture repair procedure of knee dislocation with multiple-ligament injury at acute stage., Methods: From February 2006 to November 2007, 9 patients suffering from single knee closed dislocation with multiple-ligament injury underwent open in situ suture repair procedure with non-absorbable thread and managements of other combined injuries simultaneously. Nine patients included 6 males and 3 females, aged 34-52 years old. The injured knees were left side in 4 cases and right side in 5 cases. Injuries were caused by traffic accident in 8 cases and heavy-weight crushing in 1 case. EMRI and arthroscopic examination showed that all patients suffered from the avulsion injuries of anterior cruciate ligament and posterior cruciate ligament. The time from injury to operation was 4 to 7 days with an average of 5.1 days., Results: No bacterial arthritis occurred after operation. Subcutaneous ligated fat occurred and cured after symptomatic treatment in 2 cases, other incisions healed by first intension. All patients were followed up 12 months. At 12 months postoperatively, 2 patients' flexion range of the suffering knees lost 10 degrees when to compared with normal knees, and the range of motion was from 0 to 125 degrees. The Lysholm knee scores were 83-92 (average 86.3), the results were excellent in 3 cases and good in 6 cases. The posterior drawer test and anterior drawer test were one-degree positive in 3 cases respectively; the Lachman tests were one-degree positive in 5 cases, lateral stress tests were negative in all cases., Conclusion: In situ suture repair procedure of knee dislocation with multiple-ligament injury at acute stage has the advantages such as reliable fixation, simultaneous management of other combined injuries and satisfactory short term effect.

Objective: To evaluate the feasibility and effectiveness of allograft osteochondral transplantation with arthroscopic assistance for osteochondritis dissecans (OCD) associated with large osteochondral defects., Methods: From January 2004 to May 2007, 13 patients with OCD with large osteochondral defects were treated. There were 7 males and 6 females, aged 18-59 years with an average of 35.8 years. The locations were left side in 8 cases and right side in 5 cases. The disease course was 7 days to 20 years with the median duration of 42 months. Four cases had obvious sprained history. The involved locations were lateral portion of the medial femur condyle (MFC) in 5 cases, trochlea area of MFC in 2 cases and lateral femur condyle in 6 cases. The range of motion was (95.0 +/- 13.5) degrees and the Lysholm score was 62.23 +/- 7.79. According to International Cartilage Repair Society classification system and the Guhl classification of OCD under arthroscopy, all the patients were type IV. Defect areas were 3-7 cm2 with an average of 4.32 cm2. The depths of defects were 0.8-2.0 cm with an average of 1.55 cm. Allograft osteochondral transplantation combining with adsorbable screw was applied for the lesions. The patients were closely instructed to do exercise through following up., Results: The wounds all healed by first intention. Thirteen cases were followed up for 2.2 years (14 months to 4 years) after operation. Three months after operation, 2 cases had pain after continuous exercise for 1 hour, they were directed in the methods of functional exercise and to strengthen their quadriceps femoris. Medicine was given in 2 patients who had sign of friction feeling of joint 6 months after operation. The range of motion at the last follow-up was (137.0 +/- 9.8) degrees, showing statistically significant difference when compared with that before operation (P < 0.05). The X-rays and EMRI examinations at following-up indicated that bone healed well and articular facet was integrity. The Lysholm score was 92.08 +/- 7.64 one year after operation, showing statistically significant difference when compared with that before operation (P < 0.05)., Conclusion: Allograft osteochondral transplantation with arthroscopic assistance is a useful method in treatment of OCD with large osteochondral defects of the knees.

Objective: To investigate the clinical outcomes of the treatment of knee dislocation with multiple ligaments injuries by anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) reconstruction under arthroscopy and repair of the injured structures of the knee joint., Methods: From July 2003 to August 2006, there were 24 patients with knee dislocation (19 males and 5 females), with the average age of 42 years (ranging from 20 years to 69 years), whose ACL and PCL were reconstructed under arthroscopy and whose collateral ligaments and other structures of the knee were repaired [8 with injuries of ACL, PCL, medial collateral ligament (MCL) and lateral collateral ligament (LCL); 12 with injuries of ACL, PCL and MCL; 4 with injuries of ACL, PCL and LCL]. There were 1 case with common peroneal nerve injury, 3 with medial meniscus injury and 7 with lateral meniscus injury. Every patient had single knee dislocation. The outcome was measured from the following aspects: range of the knee, complication, clinical improvement and Lysholm scoring., Results: Twenty-four patients were followed up for 11 months to 36 months, with the average time of 25 months. Eleven patients (45.8%) recovered to the normal sports level and 13 (54.2%) patients' knee function improved significantly so that they could walk by themselves. Lachman test, anterior drawer test and posterior drawer test were negative in 24 patients. The side-to-side difference was less than 5 mm in 24 patients. There were 4 patients who had slight knee stiffness. One patient's feeling and sports function of the general peroneal nerve improved to the normal level. Lysholm scale of the knee function was 41.8 +/- 4.3 preoperatively and 87.0 +/- 6.0 postoperatively (P < 0.05). The movement ranges of the knee were (87.5 +/- 12.5) degrees preoperatively and (125.0 +/- 9.2) degrees postoperatively (P < 0.05)., Conclusion: Reconstructing the ACL and PCL and repairing other structures of the knee is an effective method to treat dislocation of the knee.