[Objective] To enhance the understanding of the diagnosis of benign tumor in the knee joints.[Method] Thirteen patients(9 males and 4 females,aged 7 to 49 years,38.2 years arerage)with tumor in the knee joints were diagnosed and treated under arthroscopy since 1996.There were 3 with the synovial hemangioma,2 with tensoynovial giant cell tumor,4 with ganglion cysts of cruciate ligament and synovial cysts,1 with chondroma in the soft tissue,2 with desmoid tumor in the cruciate ligament and 1 with cruciate ligament desmoid.The curative effects were observed through a follow-up of more than half a year.[Result]All the cases were diagnozed under arthroscope and confirmed by the pathological examinations.All the patients were treated under arthroscope and followed by 11 months to 6 years.Clinical symptom improved obviously and no recurrence was found after the operation.Assessment of the curative effects were 46% excellent,39% good and 15% fair.[Conclusion]Benign tumor in the knee joints is rare.It's often difficult to diagnoze in the clinical practice.Arthroscopy is a very useful method for the diagnosis and treatment of the suspected patients with benign tumor in knee joints.

[Objective]To investigate the mechanism and pathologic changes of anterior cruciate ligament impingement syndrome as well as its arthroscopic diagnosis and treatment.[Method]From January 2005 to June 2007,28 patients with a history of anterior cruciate ligament impingement were diagnozed and treated arthroscopically.The patients' clinical findings were mainly anterior patellar pain and limited knee joint.The reasons of anterior cruciate ligament impingement syndrome were indentified by routine arthroscopic examination:straitness of intercondylar notch or osteophytes formation in 19 cases,old avulsion fracture in the tibial intercondylar in 4 cases,anterior cruciate ligament cyst in 3 cases,incorrect tibial tunnel placement on reconstructed anterior cruciated ligament in 2 cases.Different surgical procedures were carried out according to the results of the examination:joint debridement and intercondyle's plasty;intercondyle's plasty and osteophytes resection;joint debridement and ACL cysts resection;ACL tibial eminence insertion reconstruction were performed.[Result]Twenty-eight cases were followed for an average of 15 monthes(6-34 monthes).The rate of good to excellent was 82.1%,recurrence was observed in 1 case.[Conclusion]The gradual constriction of the knee is mainly caused by the anterior cruciate ligament impingement syndrome.Arthroscopy is very valuable in diagnosis and treatment of anterior cruciate ligment impingement syndrome.It can also acquire whole assessment of the joint injuries and makes out reasonable treatment program to normal knee joint function.

BACKGROUND:Early knee ioint prosthesis is used to relieve severe pain of patients．With continuous modification，the knee joint prosthesis with high flexion has developed．OBJECTIVE：To compare the clinical outcome between fixed platform high—flexion prosthesis and rotating platform high-flexion prosthesis following total knee arthroplasty．DESIGN：Non-randomized concurrent control trial of patients．PARTICIPANTS：Thirty-four patients(50 knees)with severe osteoarthritis underwent total knee replacement in Department of Bone and Joint,Tianjin Union Medicine Center from January to December 2006．METHODS：Of 34 patients，16(25 knees)underwent fixed platform high-flexion prosthesis replacement(LPS flexion，Zimmer，USA)，and 18(25 knees)underwent rotating platform high-flexion prosthesis replacement(PFC sigma RPF prosthesis．Johnson & Johnson,USA)．MAIN OUTCOME MEASURES：Knee joint function was evaluated using Hospital for Special Surgery Knee Score (HSS)before and 2 weeks，1，3 and 6 months after surgery．In addition，range of flexion of the knee was observed at 6 months postoperatively．RESULTS：Thirty-four cases completed the treatment and were followed up for 6 months．HSS scores of patients undergoing rotating platform high-flexion prosthesis replacement were higher than fixed platform high·flexion prosthesis replacement group at 2 weeks postoperatively(P<0．05)，while no differences were found in HSS scores at 1，3 and 6 months after surgery(P>0．05)．In addition，there were no significant differences in the range of flexion of the knee at 6 months postoperatively[(130．4±15．2)°，(129．9±13．8)°，P>0．05]．CONCLUSION：Fixed platform and rotating platform high-flexion prosthesis replacement exhibit similar early effects on severe osteoarthritis．

Objective To detail our early experience on a modified two-stage revison using articulating antibiotic-loaded cement spacer (AALCS) for late periprosthetic infection of total knee arthroplasty (TKA).Methods From January 2006 to February 2009,a series of 21 patients (21 knees) underwent twostage revision knee arthroplasty for late infected TKA.There were 8 males and 13 females,aged from 56 to 83 years (average,64.4 years).In the first stage,each patient underwent radical debridement,removal of all components and cement,and implantation of articulating cement spacer containing vancomycin.Graduated knee motion and partial weight bearing activity were encouraged in the interval period.Each patient received an individual systemic organism-sensitive antimicrobial therapy for 4.9 weeks (range,2-8 weeks) followed by a second-stage revision TKA.All the patients were regularly followed-up using the American Knee Society Scoring System.Results All patients were followed up for 17 to 54 months (average,32.2 months).At final follow-up,the knee society score,function score,pain score and range of motion (ROM) of knee were significantly improved compared with those before operation.Meanwhile,there was no significant increase in the degree of extension lag.The average interval period was 11.5 weeks (range,6-32 weeks).No change of bone defect volume was found between two stages.There were no complications such as recurrent infection,hepatic and renal dysfunction,and deep venous thrombosis.Conclusion Treating infected TKA with AALCS can avoid spacer-related bone loss,preserve knee function between two stages,and eradicate infection effectively without significant complications.The early clinical results are inspiring.Radical debridement,individual application of systemic antibiotics,and reasonable juncture for the second revision are all key factors related to a successful outcome.

Objective To evaluate the clinical effects of medial patellofemoral ligament reconstruction using the semitendinosus tendon autograft for the treatment of the patellar dislocation.Methods From January 2007 to January 2010,16 cases of patellar dislocation were included in this group.Lysholm score was averaged preoperatively.Arthroscopic-assisted in the semitendinosus tendon autograft reconstruction of the medial patellofemoral ligament,the central graft were fixed on the inner edge of the patellar in the upper 1/3 and the mid-point location,the end were fixed on the channel of femoral epicondyle and adductor tubercle.Results All the patients that lined progressive knee rehabilitation after operation,returned to normal walking for 3 months,6 months could be sports.Followed up for 7-54( 26.36 ± 20.48 ) months,all of patients incision were healed as grade Ⅰ,knee function were normal.Postoperative Lysholm score (93.21 ± 4.68) scores compared with preoperative ( 76.53 ± 8.35 ) scores was significant difference (P ＜ 0.05 ).Conclusions Using the semitendinosus tendon autograft for the treatment of the patellar dislocation method is simple and can effectively restore normal patellar trajectory.At the same time,which is an effective surgical method to treat recurrentdislocation of the patellar.

Objective To investigate the effect of gender differences in distal femoral geometry on the clinical outcomes of total knee arthroplasty (TKA). Methods From March 2003 to October 2006, 213 cases with 294 osteoarthritic knees who had underwent primary TKA were involved in the study. The study included 87 men (118 knees) and 126 women (176 knees) who had a mean age of 64.4 years. All the cases were assessed with the knee-rating system of Knee Society, the knee range of flexion (ROF), corrected posterior offset (PCO) and anterior condylar offset (ACO) based on sex. Results Each patient had a Minimum of 2 years follow-up. The preoperative Knee Society scores and ROF, the two-year postoperative changes of stability scores and walking ability had no differences between the two groups. While greater improvements of postoperative pain scores and stair-climbing ability were seen in male. Men had better intraoperative ROF than women had ones, but there were no gender differences with regard to the two-year postoperative improvement of ROF. Corrected PCO decreased more markedly in female than in male. Corrected ACO decreased equally in female and male. The difference in the posterior condylar offset after TKA was statistically correlated with the change in pain scores, stair climbing ability and intraoperative ROF, respectively. Conclusion Male had a better outcome than female did after TKA. Femoral components which designed in the light of Caucasian anatomic characteristics couldn't match the native anatomy of distal femurs of Chinese female. Sexual dimorphism in humans and anatomic variations in various ethnic groups should be seriously considered in total knee prosthesis design.