Objective To evaluate the surgical technique and the results of anterior cruciate liga- ment reconstruction using semitendinosus and gracilis tendons over-the-top repair. Methods 16 patientswere operated upon. The mean period of follow-up was 20. 3 months. Results Each patient was evaluatedusing the knee functional scales, 6 patients (37. 5% ) were clinically rated as excellent, 8 cases(50% ) asgood and 2 cases(12. 5% ) as fair results, there was no poor result. POst-operatively most of the patients hadapparent improvement in function of walking and daily activities. Conclusion The semitendinosus andgracilis tendons over-the-top repair is a sound and effective method of treating anterior cruciate ligament insufficiency. The key points of success of this operation are: I ) maintaining appropriate tension during fixation of both of the grafted tendons, 2) the lateral collateral ligament if injured, must be repaired, 3) in additionPOstoperative functional exercise play a very important role in the outcome.

AIM: To investigate the effects of deep-frozen treatment on the immune response of bone-patellar tendon-bone(BPB) xenograft rejection.METHODS: A muscle pocket model was used to study the immune response of rat to deep-frozen treated BPB xenograft from guinea pig,autograft and fresh xenograft served as controls.The expression of T-cell surface activation antigen CD25 in the peripheral blood and the morphological changes of the implants were used to measure the immune response.RESULTS: The expression of CD25 in CD4+,CD8+ cells greatly increased 3 d after fresh BPB xenograft,the obvious difference to that of autograft(P