Medical Student Research Fellowship for Summer 2012

Mentor: Dr. Michael Khazzam
Department: Orthopedic Surgery
Room number: WA 4.314
Mail Code: 75390-8883      
Phone number: 214- 645-8917
E-mail: Michael.khazzam@utsouthwestern.edu   
Project title: Acute versus Chronic (Delayed) Rotator Cuff Repair in a Rat Model

Human subjects IRB approved project number (where applicable):       N/A

Animal subjects IRB approved project number (where applicable):   Pending

Project Type Animal-based research

Brief Description of Project:

Methods of enhancing biologic tendon to bone healing following rotator cuff repair has been an area that has received a large amount of research attention. The goal of this study is to evaluate the healing characteristics of a full thickness rotator cuff tear that has undergone delayed repair in a rat animal model. The purpose of this project is to examine the histology, biomechanics, and inflammatory cascade of rotator cuff repair in the setting of a chronic full thickness rotator cuff tear in a rat model. The findings from this study can be used to determine how tendon to bone healing is biologically altered in the chronic rotator cuff tear setting. This study will examine the differences seen during the healing process following surgical repair of a chronically torn rotator cuff as compared to acute repair.
Using the information from past studies we developed our chronic rotator cuff tear protocol. Prior to surgery animals will be randomized to either acute repair or delayed repair groups. Animals will then undergo surgical detachment of the supraspinatus tendon. Those subjects randomized to the acute repair group will undergo immediate repair and subjects who are randomized to the delayed repair group will undergo surgical repair 2 to 3 weeks later. Surgical rotator cuff repair will consist of suture repair of the detached supraspinatus tendon to the greater tuberosity through bone tunnels. Subjects will then be euthanized at 2, 4, and 6 weeks post rotator cuff repair for analysis of biomechanical strength of repair, histologic characteristics of the tendon to bone healing site, mRNA analysis of the repair cascade and genes/markers of inflammation, and analysis of glenohumeral joint synovium and synovial fluid. These results will be compared between the acute and delayed repaired groups for differences using methods described in the sections to follow. The contralateral limb will be used as a control in each case.
The student will be involved with data collection and organization, literature search and review, animal surgery and manuscript preparation.

Previous Research Activities or Publications with Medical Students:

None at UT Southwestern