points preoperatively to 1.11.1 points at FU1 and 1.11.1 points at FU2. Conclusion: Arthroscopic repair or partial recon- struction is advisable even in patients with massive ro- tator cuff tears as it led to significant improvements in function, pain and patient satisfaction in active patients suffering from a symptomatic massive rotator cuff tear. Rotator Cuff Tears as a Complication of Portal Place- ment (SS-44). Scott Mair, MD, and Joel Hurt, MD An accessory trans-rotator cuff portal is commonly utilized in shoulder arthroscopy, primarily in the repair of SLAP lesions. This portal has become popular as it provides access to the superior glenoid and labrum. Im- proper placement of this portal can result in damage to the rotator cuff near its attachment to the greater tuber- osity. We wish to stress the importance of proper place- ment of this portal and the potential for complications with its use. Six patients were referred to our clinic after previous shoulder arthroscopy with SLAP repair. Mean age of the patients was 34.4 years (range 17-44 years). There were five males and one female. ASES scores at time of presentation averaged 45.4 (range 34-60). 5 of 6 reported that their symptoms were worse after the index surgery. Review of operative notes showed that the ro- tator cuff had been described as normal in five patients at the time of the first surgery. The other patient was described as having a mild partial supraspinatus tear. All patients underwent repeat shoulder arthroscopy. Mean time period from the index to revision surgery was 15.0 months (range 10-22 months). All 6 patients were found to have significant rotator cuff tears associated with portal placement from their first surgery. Confirmation of the portal as the source of the rotator cuff tear was made by placing a spinal needle through the skin at the site of the previous portal. 3 of 6 patients underwent revision SLAP repair. All six were treated with rotator cuff repair: 3 with side to side repair, 3 with suture anchor repair to bone. All patients improved after revision surgery. Post- operative ASES scores averaged 90.5 (range 77-100). Mean follow-up was 16.0 months (range 8-36 months). A trans-rotator cuff portal is an accepted portal in shoul- der arthroscopy. Its proper use involves careful place- ment in order to traverse the rotator cuff medial to the muscle-tendon junction. This report highlights the poten- tial for injury to the rotator cuff tendons with improper placement of this portal. In patients with persistent pain after previous SLAP repair, where a trans-rotator cuff portal was used, consideration should be given to rotator cuff injury as the source of symptoms. Revision surgery with rotator cuff repair can provide improvement. Effects of Bipolar Radiofrequency on the Human Meniscus: A Comparative Study Between Patients Younger and Older Than 40 Years Old (SS-45). David Figueroa, MD, Rafael Calvo, Alejandro Vaisman, Miguel Carrasco, MD, Marcela Gallegos, Rodrigo Mardones, MD, and Iris Delgado Bipolar radiofrequency is frequently used in arthro- scopic surgery. It provides excellent intraarticular hemo- stasis, debridement and shrinkage of soft tissues. Al- though extensively used in meniscal surgery, there are few studies that report the ultrastructural effect of bipolar radiofrequency on the human meniscus. Furthermore, it is not clear if there is any difference between applying the same amount of energy on younger versus older menisci. The main objective of our study was to evaluate the effects of bipolar radiofrequency applied to the hu- man meniscus in 4 differents intensities and compare the results between patients younger and older than 40 y.o. Our study shows the effects of four different magnitudes of bipolar radiofrequency, commonly used in knee ar- throscopic surgery: coagulation medium and high, va- porization intensities 5 and 7. Each magnitude was ap- plied for 3 seconds on 30 human menisci resected from patients between 14 and 84 years old. The menisci were then divided in two groups: younger and older than 40 years old, and studied macroscopically, microscopically and by electronic microscopy. Thermal necrosis was found between m (D.S. 740) andm from the meniscal surface, with an average of 17000 and 4000 was sig- nificantly higher on the vaporization than the coagulation group (p  0.001). We found significative differences between patients younger or older than 40 years old in groups zone 2 and 3 (zone 2 p=0.038 and zone 3 p=0.044) We concluded that although bipolar radiofre- quency can cause deep necrosis (up to m) on the human meniscus, this effect depends on the magnitude of the 4000 energy applied and is higher when we applied medium intensity in older patients. KEY WORDS: Ra- diofrequency – Knee arthroscopy – Meniscus. Matrix-Encapsulation Cell-Seeding Technique to Prevent Cell Detachment During Arthroscopic Implantation of Matrix-Induced Autologous Chondrocyte Implantation (MACI) (SS-46). Maria Masri, MVZ, MSC, DACVIM, German Lombardero, Cristina Velasquillo, Valentin Martinez, Rosario Neri, Hilda Villegas, PhD, and Clemente Ibarra, MD Arthroscopic implantation of matrix–induced autolo- gous chondrocytes (MACI) can be limited by fluid flow that can affect cell attachment to the matrix. The goal of this study is to evaluate the efficiency to obtain a larger e23 ABSTRACTS