What I Need to Know and Why
Research
When I was about 10 years old, I began my first of many physical therapy session at Children's Healthcare of Atlanta (CHOA). CHOA unfortunately became like a second home for me due to many injuries from playing travel soccer. Despite the injury part, I liked being at CHOA for many reasons. The environment was always friendly and the work the therapists did was so intriguing to me. I vividly remember hearing a girl screaming in agony because the therapists were working on bending her knee. This is an everyday thing for you and I. However, this girl had torn her Anterior Cruciate Ligament (ACL). Her post operation recovery had not been carried out properly, and she had not fully regained the ability to completely bend her leg. I instantly became intrigued with ACL tears and the recovery process, and my interest in them grew as I watched many of my own friends and girls I knew tear theirs during travel soccer. I chose to research this topic because I have in interest in becoming a sports medicine physical therapist in the future. When I heard that test surgeries were being conducted using stem cells in ACL reconstruction, I immediately needed to know more. I wanted to know how using stem cells in ACL reconstruction surgery would strengthen the knee as well as speed up the recovery time in the future.
What I Know or Assume
Before my research, my knowledge about ACL tears and stem cells was limited. I have witnessed many of my friends tear their ACLs and have heard them talk about the long and rough recovery process. ACL recovery typically lasts six to nine months. The way recovery is carried out is based on the patient. Depending on how well the patient is doing, the exercises and mobilization become more rigorous in each phase. The process focuses on regaining full mobility and strength as comparative to before the tear. Previously, all I thought about stem cells was that they were far more advanced than any other cell, and they had a way of improving almost every problem in the human body.
My Research Process
My research process began with identifying the current ACL reconstruction therapy protocol. I was able to look at CHOA's guidelines for therapy of the ACL during one of my shadowing days. Attached below is a link to an ACL protocol that is similar to CHOA's.
ACL recovery typically takes anywhere from six to nine months depending on the patient. CHOA carries out recovery based on phases. When the patient is showing signs of improving strength, balance, and flexion of the knee, they are able to move onto the next phase, which is typically more rigorous and aimed toward the return to play phase.
Typical ACL reconstruction surgery takes tissue from either the patellar tendon, hamstring, quadricep or a cadaver in order to create a graft to replace the torn anterior cruciate ligament. This new ACL reconstruction surgery adds a step and uses Mesenchymal stem cell (often referred to as BD-MSCs) injections for the enhancement of tendon-to-bone healing. Mesenchymal cells are non-hematopoietic (not producing blood cells) stromal cells that can differentiate into a plethora of different cell types such as Osteoblasts (bone cells), Chondrocytes (cartilage cells), Myocytes (muscle cells), and Adipocytes (fat cells). Their ability to transform into any of these cells has created an interest in the study of using them in tendon-to-bone healing in ACL reconstruction surgery.
Based on a study conducted by researchers at the Medical School of Southeast University in China, the origin of the stem cells can affect the overall recovery process. This experiment used animal test subjects, but injected human stem cells. There were three main types of stem cells studied which were bone marrow derived mesenchymal cells (bMSCs), synovial mesenchymal cells (sMSCs), and stem cells derived from ACL tissue (CD34+). The different types of cells were either injected directly or embedded into the fibrin glue in order to transfer the stem cells into the bone tunnel. While each of these cells showed some signs of improving the recovery, the CD34+ cells seemed to provide the most promising direction for stem cell treatment. These cells provide the earliest remodeling of tendon-to-bone attachment and in return, result in perhaps the strongest and quickest healing method.
Not many clinical experiments have been conducted on human ACLs yet, and the data has not been published. With further investigation and experimenting, the ACL recovery process will hopefully reduce in time and graft failure rates due to stem cell therapy.
Embedded below is an Interview with my Mentor Chris Wilhelm who is an Orthotist.
What I Concluded
ACL reconstruction recovery is a difficult and tiresome process for many athletes. Their road back to full time play is often long and drawn out. The use of stem cells in ACL reconstruction has provided a hopeful advancement for those going through this process. Stem Cell therapy has had promising effects on animals based on a reduced recovery time and stronger tendon-to-bone healing. While clinical experiments are beginning to make their way in humans, the evidence has not yet been published. Because of my research, I am confident in saying that those with ACL tears in the future will experience an easier road back to full time play. ACL injuries have been career ending for many athletes I know. Stem cell therapy is inspiring many surgeons and orthopedists around the world to continue the research and help reduce the number of athletes that give up on their passion.
Works Cited
Freedman, Jason A. “ACL Reconstruction Post-Operative Rehabilitation Protocol.” Orthopedic Surgery.
Zi-Chen, Hao, et al. "Stem Cell Therapy: A Promising Biological Strategy for Tendon-Bone Healing After Anterior Cruciate Ligament Reconstruction." Cell Proliferation, vol. 49, no. 2, Apr. 2016, pp. 154-162. EBSCOhost, doi:10.1111/cpr.12242.
Wilson, B. P., & Freudigman, P. M. (2017). Sports medicine. Magill’s Medical Guide (Online Edition)
Zi-Chen, Hao, et al. "Stem Cell Therapy: A Promising Biological Strategy for Tendon-Bone Healing After Anterior Cruciate Ligament Reconstruction." Cell Proliferation, vol. 49, no. 2, Apr. 2016, pp. 154-162. EBSCOhost, doi:10.1111/cpr.12242. (MLA)
“Center for Regenerative Medicine - About Regenerative Medicine.” Mayo Clinic, 20 Oct. 2017, www.mayo.edu/research/centers-programs/center-regenerative-medicine/patient-care/about-regenerative-medicine.