BACKGROUND: At present, there are different strategies for treating unsteable osteochondritis dissecans of the knee joint in adolescents, but their therapeutic effects are not ideal. OBJECTIVE: To assess the therapeutic effect of bioabsorbable pin fixation on functional recovery and fracture healing in juvenile unstable osteochondritis dissecans through Lysholm, IKDC, Hughston scoring and imaging examination. METHODS: Eighteen patients with unstable osteochondritis dissecans were enrol ed. Under arthroscopy, a smal incision was localized and cut fol owed by bioabsorbable pin fixation. The average fol ow-up period was 2.7 years. Functional recovery of the affected limbs after fixation was assessed by using Lysholm, IKDC and Hughston scoring. X-ray examination was used to observe fracture healing. RESULTS AND CONCLUSION: At 6 months after fixation, the Lysholm and IKDC scores were improved significantly as compared with those before operation and maintained til the last fol owing up. There were 15 patients scored as excel ent, 2 as good and 1 as poor. X-ray films also showed that there were 17 cases of fracture healing (94% healing rate). The average fracture healing time was 2.9 months. These findings indicate that the bioabsorbable pins can improve the bone healing in juvenile unstable osteochondritis dissecans.

BACKGROUND:The meniscus injury is one of the most common sports injuries of knee joint. The treatment after injury is always a difficult problem in the clinic. Researchers have been trying to apply the method of using tissue-engineering to solve the problem of meniscus repair after injury.
OBJECTIVE:To summarize tissue-engineered meniscus-related basic research.
METHODS:The first author retrieved China National Knowledge Infrastructure and Medline for literatures on tissue-engineered meniscus. The key words were“meniscus, tissue engineering, basic research”. Articles with unrelated objective and repeated articles were excluded. Final y, 35 articles were included.
RESULTS AND CONCLUSION:There was some controversy about the classification of the cel of the meniscus. The outer tissue of the meniscus is mainly composed of the fibrous cartilage cel s and the extracel ular matrix. The inner tissue of the meniscus is mainly composed of a smal atypical class of cartilage cel s. The biomechanical properties of the meniscus can be properly adjusted when it is subjected to external pressure. The lateral meniscus is assumed to bear al the pressure of the outer part of the knee joint during knee flexion, but the medial meniscus is assumed to bear 50%of the medial part of the knee joint. The etiology and pathophysiology of meniscus injury are not the same, which is highly dependent on the age of onset of the patient. However, in each age group, right knee meniscus injury was the majority. The way of surgical repair of the meniscus tear can be divided into the technology from inside to outside, and that from outside to inside, total internal repair under arthroscopy and open repair technology.

BACKGROUND:Growth differentiation factor-5 can induce adipose-derived stem cels into chondrocytes in our previous studies, but it has not been reported that the adipose-derived stem cels induced by growth differentiation factor-5 can differentiate into chondrocytes on the type I colagen scaffold. OBJECTIVE:To investigate the chondrogenic differentiation ability of adipose-derived stem cels induced by growth differentiation factor-5 cultured on the type I colagen scaffold. METHODS:Adipose derived stem cels were isolated from rabbit adipose tissue, the cels morphology was observed using inverted phase contrast microscope and the phenotypes were identified using immunofluorescence. The exogenous growth differentiation factor-5 was added to the cultural media with the type I colagen scaffold so as to induce the chondrogenic differentiation. The cels morphology was observed using hematoxylin-eosin staining and scanning electron microscope after the induction by growth differentiation factor-5 for 14 days. Meanwhile, the type II colagen and aggrecan mRNA expressions of the induced cels were measured using RT-PCR after the induction by growth differentiation factor-5 for 7, 14, and 21 days.RESULTS AND CONCLUSION:The primary cultured adipose-derived stem cels proliferated adherently with the fusiform and polygonal distribution under inverted phase contrast microscope. The positive CD44, CD49d and negative CD106 were detected by immunofluorescence. The adipose-derived stem cels induced by growth differentiation factor-5 were wel adhered to the type I colagen scaffold and strongly proliferated. The large amounts of extracelular matrix existed on the surface of the induced cels under scanning electron microscope. RT-PCR agarose gel electrophoresis indicated that the type II colagen and aggrecan mRNA expressions of the adipose-derived stem cels induced by growth differentiation factor-5 with the type I colagen scaffold were significantly increased. Growth differentiation factor-5 can successfuly induce the chondrogenic differentiation of adipose-derived stem cels cultured on the type I colagen scaffold.

BACKGROUND:Anterior cruciate ligament (ACL) has been reported to hold a self-recovery potential, which may be related to certain cytokines and biological factors, such as stem cells or progenitor cells.OBJECTIVE: To review the literatures about the relationship between mesenchymal stem cells and ACL injuries, and understand the potential of stem cells or progenitor cells differentiating into ACL, thus providing a basis for the clinical use of mesenchymal stem cells in the treatment of ACL injury. METHODS:A computer-based online research of PubMed databases was performed to collect articles including reviews, clinical trials and basic studies using the English keywords of ACL regeneration, stem/progenitor cells, mesenchymal stem cells. Forty-five eligible articles were included finally. RESULTS AND CONCLUSION:In recent years, there are a lot of studies addressing the treatment of ACL injuries and muscle/bone regeneration, but the use of stem cells is still far from the clinical requirements. The source of stem cells suitable for the ACL regeneration and their most suitable injection points are under discussion. Although the mesenchymal stem cells have been reported to successfully repair ACL injury in animal models, either trophic factors of stem cells or these cells themselves improving the regeneration remains unclear.

BACKGROUND:As meniscectomy may result in various adverse reactions, tissue-engineered meniscus is expected to be used for meniscus repair. Seed cel selection and optimal physicochemical stimuli are crucial for the construction of tissue-engineered meniscus.
OBJECTIVE:To overview the seed cel s for the tissue-engineered meniscus construction and the research progress of physicochemical factors.
METHODS:The first author retrieved the CNKI and Medline databases using the keywords of“meniscus, tissue engineering, seed cel s, physical and chemical factors”in English and Chinese, respectively, to retrieve articles related to the seed cel s and physicochemical factors of the tissue-engineered meniscus construction. Irrelative and repetitive articles were excluded, and 49 eligible articles were enrol ed for analysis.
RESULTS AND CONCLUSION:The seed cel s must maintain their phenotype and synthetic ability after physicochemical stimulation in combination with scaffolds, to achieve the reproducibility of tissue-engineered meniscus. Most of cytokines can be used for promoting the proliferation and differentiation of chondrocytes, but the underlying mechanisms were little known. Their application in the meniscus tissue engineering needs to be studied in depth. Currently it is urgent to improve physicochemical stimuli in order to construct the tissue-engineered meniscus. The shear force does harm to chondrocyte phenotype, and dynamic compression loading has been proved to enhance Ca+and glycosaminoglycan release. The fibrous cartilage stimulated by shear force and other factors may be helpful for constructing the tissue-engineered meniscus. An elaborated randomized control ed trial and the long-term quantitative analysis are of importance to assess the research results.

BACKGROUND:The treatment method of tibial avulsion fractures of anterior cruciate ligament is varied;each has its advantages. OBJECTIVE:To investigate the methods and clinical effects of the treatment of avulsion fractures of tibial insertion of anterior cruciate ligament by the means of making two decussate lines and four strands of non-absorbable Arthrex sutures passing through two bone tunnels combined with pushlock free knotting anchor under arthroscopy. METHODS:From December 2014 to November 2015, 23 cases of avulsion fractures of tibial insertion of anterior cruciate ligament were treated in the Second Hospital of Inner Mongolia Medical University. Under the arthroscopy, avulsed fracture was fixed in tibial intercondylar eminence by the means of making two decussate lines of Arthrex sutures passing through. At the same time, pushlock free knotting anchor beside tibial tubercle provided a tightening of tension for Arthrex sutures, which could strengthen the fixation of avulsion fracture blocks. Knee joint Lysholm and Tegner scores were fol owed up. Knee stability was evaluated by anterior drawer test and Lachman test. Postoperative reset and healing were evaluated with X-ray films. RESULTS AND CONCLUSION:(1) Al 23 patients were fol owed up for 6 months to 1 year. (2) Lysholm scale of the knee function was (47.31±6.16) preoperatively and (94.69±1.28) postoperatively (P<0.05). Tegner score was (3.14±1.58) preoperatively and (7.74±1.69) postoperatively (P<0.05). (3) Lachman test of al cases was negative. X-ray films demonstrated that fracture healing was good. There was no repeated swel ing or cross locking of the joint. The knee was not limited by flexion or extension. No infection or deep venous thrombosis of lower extremity occurred. (4) The method of Arthrex sutures passing through two bone tunnels combined with pushlock free knotting anchor under arthroscopy has the advantages of minimal y invasive, simple operation, reliable fixation, no metal implants and satisfactory result to treat the tibial intercondylar eminence fracture of anterior cruciate ligament.

BACKGROUND:Autologous hamstring Rigidfix and Intrafix has been frequently used to fix and reconstruct anterior cruciate ligament. However, it lacks of evaluation of middle and long period of clinical outcomes. OBJECTIVE:To retrospectively evaluate the medium term clinical outcomes of anterior cruciate ligament reconstruction with hamstring tendon autograft by Rigidfix and Intrafix. METHODS:The 39 cases of anterior cruciate ligament injury were subjected to anterior cruciate ligament reconstruction with hamstring tendon autograft by Rigidfix and Intrafix under arthroscope. They were fol owed up for 2 years or more. The clinical outcomes were evaluated using Lyshlom score scale, IKDC2000 and Tegner score scale. RESULTS AND CONCLUSION:In the fol ow-up, IKDC2000 score and Lyshlom score were significantly increased fol owing Rigidfix and Intrafix fixation than before treatment (P<0.01). Results indicate satisfactory clinical outcomes of anterior cruciate ligament reconstruction with hamstring tendon autograft by Rigidfix and Intrafix. However, long-term fol ow up is needed to verify the feasibility of extensive application.

BACKGROUND:Alogeneic tendon has been frequently used to reconstruct the anterior cruciate ligament. However, there is a lack of middle- and long-term clinical evaluation. OBJECTIVE:To evaluate the middle- and long-term curative effect of alogeneic tendon reconstruction of the anterior cruciate ligament under arthroscopy. METHODS:Twenty-five patients with anterior cruciate ligament injury under alogeneic tendon transplantation were reviewed retrospectively. They were al folowed up for 3 years or more. The clinical outcomes were evaluated and compared using Lyshlom score scale, IKDC2000 and Tegner score scale. RESULTS AND CONCLUSION:Al the patients were folowed up. Lysholm scale scores on the knee function, Tegner scores and IKDC scores were significantly increased after transplantation (P < 0.05). No complications of infection and compartment syndrome occurred. Symptoms were relieved and the function of knee joint was improved. There was one case weakly positive for anterior drawer test. Both Lachman test and pivot shift test showed negative signs. Overal, the reconstruction of anterior cruciate ligament with alogeneic tendon has less trauma and complications, with good middle-term efficacy.

BACKGROUND:Autologous hamstring tendon reconstruction of the medial patel ofemoral ligament is now more popular surgical procedure.
OBJECTIVE:To study the clinical mid-term outcomes of isolated medial patel ofemoral ligament reconstruction for recurrent lateral patel ar dislocation.
METHODS:The clinical data of 24 patients (25 knees) undergoing medial patel ofemoral ligament reconstruction for recurrent patel ar dislocation from September 2006 to September 2009 were retrospectively studied. Clinical, functional, and CT outcomes were assessed at an average of 3.1 years after surgery (range, 2-5 years), using recurrent instability as the primary end point.
RESULTS AND CONCLUSION:The success rate of medial patel ofemoral ligament reconstruction for preventing recurrent dislocations was 92%. Two patients (8%) experienced a recurrent lateral patel ar dislocation, and required a reoperation. At final fol ow-up, the mean IKDC, Tenger and Lycholm scores were significantly higher than those before operation (P<0.01). Reconstruction of the medial patel ofemoral ligament for recurrent patel ar instability is a minimal y invasive operation and has a number of benefits. The mid-term clinical outcome was satisfactory.

BACKGROUND:Until now, musculoskeletal bioengineering used in the orthopedic surgery and regenerative medicine are developing. OBJECTIVE:To summarize the construction strategies for tissue-engineered knee ligaments. METHODS:A computer-based online search was conducted in PubMed to screen the relevant literatures using the terms“knee ligament”AND“tissue engineering”OR“regenerative medicine”. The literature retrieval, data assessment and extraction were performed by both authors independently. The relevant literatures were included through reviewing preclinical and clinical studies to display the preclinical and clinical medicine progresses in the construction strategies for tissue-engineered ligaments. RESULTS AND CONCLUSION:Included 224 literatures focus on the construction strategies for tissue-engineered ligaments, including stem cel therapy, growth factors, biomaterials and scaffolds, and mechanical stimulation pattern. Construction techniques for tissue-engineered ligaments have some potential advantages, such as rapid function recovery, good tenacity, and reduced relapse. However, rigorous and high-level randomized control ed clinical trials are needed for the translation of preclinical results into successful clinical trials.