Sports Medicine Research: In the Lab & In the Field: Diabetes and Tendon Healing (Sports Med Res)
Wednesday, January 26, 2011

Diabetes and Tendon Healing

Diabetes mellitus impairs tendon-bone healing after rotator cuff repair
Bedi, A.; Fox, A. J.; Harris, P. E.; Deng, X. H.; Ying, L.; Warren, R. F.; Rodeo, S. A. J Shoulder Elbow Surg. 2010;19(7):978-988.

This study came out in the fall and won the Neer Award (the award for excellence in shoulder research) given by the Journal of Shoulder and Elbow Surgery. Several studies in the past have identified the association of diabetes and delayed healing in bone and skin, but this was the first study to demonstrate that diabetes also affects tendon healing. This study used a rat rotator cuff model to examine the affects of type I diabetes mellitus on rotator cuff tendon healing (48 rats total). One group had diabetes induced and the other served as the non-diabetic control. Both groups then underwent unilateral detachment of the supraspinatus tendon followed by immediate repair. At 1 and 2 weeks after surgery, tendon biomechanics and histology were assessed on the healing tendon. The tendons from diabetic rats had failed (ruptured) at lower loads and had abnormal collagen structure (a lack of parallel fibers). These changes demonstrate a significantly weak tendon attachment.

This is a very novel and interesting study demonstrating that diabetes plays a large role in rotator cuff tendon healing. Clinically rotator cuff tears occur frequently and the rate of re-tears is near 70%. With such a high failure rate type I diabetic patients need to be educated on proper glycemic control to minimize the risk for secondary injury and delayed healing. Although this study focused on type I diabetes, it is suggested that type II diabetes also produces similar effects. With type II diabetes at epidemic levels we need to also educate patients on proper exercise and nutrition that will help to eliminate hyperglycemia completely. In the case that an individual with diabetes does develop a rotator cuff tear we need to consider the delayed healing in our rehabilitation protocol. A more conservative rehabilitation protocol may be required to minimize the risk of retears. Specifically, longer durations of immobilization may help to improve tendon insertion site healing. Another novel approach that could be used to improve tendon healing in diabetic patients is the use of antioxidants. Several researchers believe that hyperglycemia causes oxidative stress and the use of antioxidants may reduce the deleterious affects of diabetes. Diabetes is clearly something that we need to be aware of and proper knowledge of current ongoing research will allow us to be better clinicians when it comes to treating diabetic patients.

Written by: Stephen Thomas
Reviewed by: Jeffrey Driban

6 comments:

Jeffrey B. Driban, PhD, ATC, CSCS said...

Steve:

Obviously this is an animal study and focused on the rotator cuff but do you think these findings may apply to ACL reconstructions since the grafts are often a tendon autograft?

Stephen J. Thomas, PhD, ATC said...

Jeff,

You bring up a very good point and based on the new post today it seems that in a diabetic patient the tendon graft will be weaker and potentially place them at risk for injury. I don't believe this has even been examined but should definitely be considered when choosing a graft in a diabetic patient.

Anonymous said...

I have a baseball player that had a UCL repair, and has had nothing but problems since the repair. We've used his surgeon for other athletes (Shands Hospital at U. Florida) without incident, but this kid has had problems with ROM, swelling, possibly a bleeding disorder, flexor tendon tear when actually able to get to a point in the rehab process where improvement was seen 3 months behind schedule, and now its looking like he may need to have surgery again (3rd time). He is diabetic, and well controlled, but I'm wondering if this could somehow be the source of all the complications. I've been doing some searches on Ovid and Sportsdiscus for possible further information regarding the diabetic athlete, and was wondering if you have any suggestions for journals/web-sites/resources to check too.

Stephen J. Thomas, PhD, ATC said...

That is an interesting story. As far as answers and where to look, it is very difficult. In terms of diabetic research and orthopaedics there isn't much. Mostly on the Achilles tendon. Basically what it seems like right now is that hyperglycemia causes a chemical reaction with collagen which alters its structural properties. Then when injured because of these altered properties and addition chemical signaling of cytokines (signaling proteins that regulate metabolism and inflammation)it results in poor healing. There really are no studies looking into the mechanism which truly causes this. There are some studies looking at the use of antioxidants, which oxidative stress is thought to be one mechanism. So I would suggest looking at his diet and trying to make it high in antioxidants in hopes that it will work in addition to slowing his rehab due to the delayed healing. I hope that helps and thanks for posting. Has anyone else had an experience like that? What worked? What didn't?

Kaitlyn Kelly said...

As a diabetic athlete I find this article very interesting. I have injured both my rotator cuff and my ACL, my ACL was a surgical fix and my rotator cuff was treated with just rehabilitation. At the time of my injury my blood sugar level was hyperglycemic (usually when under stress of competition it run a little hyperglycemic) but at the time of my ACL surgery it was controlled my ACL surgery graft still is in tact now. Do you think the fact my blood sugar was hyperglycemic at time of the injury could have contributed to my injury?
Thank you

Stephen Thomas, PhD, ATC said...

Kaitlyn it is difficult to know if that contributed to the injury. Most research regarding this is in patients with type II diabetes which tend to not be as controlled as type I. Based on the basic science literature blood glucose levels would need to be elevated for a few weeks to cause structural changes that may place you at risk of injury. I think maintaining a normal level during healing is very important since hyperglycemia can alter the biology and easily disrupt healing.

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