Research

Tendon healing, especially in the setting of rotator cuff repair, has proven challenging as anatomic failure rates range from 20%-94%1,2 depending on patient age, tear size, mechanical strength of repair and many other factors. Tendon healing in the adult setting is characterized by a reparative, rather than a regenerative process. Tissue is generated at the repair site, however its viscoelastic properties and insertion site characteristics vary greatly from the normal tendon to bone enthesis. Recently, there has been a tremendous amount of interest generated among biologists, tissue engineers, and surgeons in developing biologic augmentation techniques to improve rotator cuff tendon healing.
Platelet rich plasma (PRP) has been identified as a potential augmentation device. PRP is a sample of autologous blood containing a concentration of platelets 3-4 times above baseline. Platelets house alpha granules containing growth factors and cytokines involved in cell recruitment, cell proliferation, and angiogenesis. These factors make the use of PRP in the setting of tendon repair quite compelling. Application of PRP in vitro generates a proliferative response, however, these results have not necessarily been translated to a clinical improvement.
Several level I and II studies3,4 have been performed and show no differences in either clinical outcome or structural healing on MRI. One exception using platelet rich fibrin matrix showed an improvement in structural results in smaller tears, but there was no difference in clinical outcome.5 Perhaps this may be related to our method of application. Activated PRP releases approximately 90% of its factors within an hour. Non activated PRP may deliver a sustained release over a short period of 8-10 days, the life span of a platelet. It may be that the factors are not present long enough or in high concentration at the peak time of cell proliferation and extracellular matrix production of a healing rotator cuff in a human shoulder. Our challenge going forward is to perhaps utilize tissue engineering strategies to deliver growth factor at the optimal concentration, at the optimal time frame. The problem may be not what we are using, but how we are using it.
Leesa M. Galatz, MD, Associate Professor of Orthopedic Surgery, Shoulder and Elbow Service, Washington University Orthopedics, Barnes-Jewish Hospital, St. Louis, MO USA
References
1. Galatz LM, Ball CM, Teefey SA, Middleton WD, Yamaguchi K. The outcome and repair integrity of completely arthroscopically repaired large and massive rotator cuff tears. J Bone Joint Surg [Am] 2004;86-A:219–24.
2. Lafosse L, Brozska R, Toussaint B, Gobezie R. The outcome and structural integrity of arthroscopic rotator cuff repair with use of the double-row suture anchor technique. J Bone Joint Surg [Am] 2007;89-A:1533–41.
3. Castricini R, Longo UG, De Benedetto M, et al. Platelet-rich plasma augmentation for arthroscopic rotator cuff repair: a randomized controlled trial. Am J Sports Med 2011;39:258–65.
4. Jo CH, Kim JE, Yoon KS, et al. Does platelet-rich plasma accelerate recovery after rotator cuff repair? A prospective cohort study. Am J Sports Med 2011;39:2082–90.
5. Barber FA, Hrnack SA, Snyder SJ, Hapa O. Rotator cuff repair healing influenced by platelet-rich plasma construct augmentation. Arthroscopy 2011;27:1029–35.
New Research Forum launched by the British Scoliosis Research Foundation
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