SLR - July 2015 - Chad Rizzardi

Autologous Growth Factor Injections in Chronic Tendinopathy

Reference: Sandrey MA. Autologous growth factor injections in chronic tendinopathy. J Athl Train. 2014 May-Jun;49(3):428-30.

Scientific Literature Review

Reviewed By: Chad Rizzardi, DPM
Residency Program: Pinnacle Health

Podiatric Relevance: As podiatric surgeons, we commonly encounter not only acute tendon conditions but also chronic ones. These chronic tendon conditions may be treated with a multitude of modialities including autologous whole-blood and platelet-rich-plasma (PRP) injections. This studies’ authors performed a systematic literature review to ascertain if there is sufficient evidence to support the use of injections of growth factors delivered through autologous whole-blood and PRP injections in managing chronic tendinopathy of the wrist-flexor and -extensor tendinopathies, plantar fasciopathy, and patellar tendons.

Methods: The authors performed a comprehensive, systematic literature search in October 2009 using PubMed, MEDLINE, EMBASE, CINAHL, and the Cochrane library without time limits. Studies were eligible based on the following criteria: (1) if the participants had been clinically diagnosed as having chronic tendinopathy; (2) the design had to be a prospective clinical study, randomized controlled trial, nonrandomized clinical trial, or prospective case series; (3) a well-described intervention in the form of a growth factor injection with either PRP or autologous whole blood was used; and (4) the outcome was reported in terms of pain or function. All titles and abstracts were assessed by 2 researchers, and all relevant articles were obtained. The data extracted included number of participants, study design, inclusion criteria, intervention, control group, primary outcome measures, time of follow-up, and outcomes for intervention and control group using a standardized data-extraction form. Function was evaluated in 9 of the 11 studies using scales such the rearfoot score from the American Orthopaedic Foot and Ankle Scale.

Results: Using the specific search criteria, the authors identified 418 potential sources. After screening they excluded 407 sources, which left 11 studies for analysis. Six of the 11 studies were of an observational, noncontrolled design; the remaining 5 studies were controlled clinical trials. The mean number of participants included in the studies was 40.5 (range = 20 to 100). Three of the studies were on plantar fasciopathy. Based on the information reported, there was no standardization of frequency or method of growth factor injection treatment or of preparation of the volume, and an optimal mixture was not described. Autologous whole-blood injections were used in 8 studies; in 5 studies, the autologous whole-blood injection was combined with a local anesthetic. In contrast, a local anesthetic was used in only 1 of the 3 PRP injection studies. The number of autologous whole-blood and PRP injections varied, ranging from 1 to 3. The centrifuging process was single or double for the PRP injections. In 2 studies, calcium was added to activate the platelets. A visual analogue or ordinal pain scale was used in 10 of the 11 studies. Function was evaluated in 9 of the 11 studies using various scales including the rearfoot score of the American Orthopaedic Foot and Ankle Scale for 1 plantar fasciopathy study. All intervention groups reported a significant improvement in pain or function score, with a mean improvement of 66% over a mean follow-up of 9.4 months. The control groups in these studies also showed a mean improvement of 57%. None of the pain benefits among the intervention groups were greater than those for the control group at final follow-up. In 4 of the studies, the control group and the autologous growth factor injection group had similar results in pain or function or both, whereas in 2 studies, the control group had greater relief in pain than the injection group. The 3 high-quality plantar fasciopathy studies used autologous growth factor injections but did not show a significant improvement over the control group. One of the studies that showed no beneficial effect for the autologous growth factor injections was compared with corticosteroids. Compared with other treatments, level 1 evidence demonstrated that autologous growth factor injections did not improve pain or function in plantar fasciopathy.

Conclusions: Strong evidence indicates that autologous growth factor injections do not improve plantar fasciopathy pain or function when combined with anesthetic agents or when compared with corticosteroid injections, dry needling, or exercise therapy treatments. Furthermore, limited evidence suggests that PRP injections are beneficial. Except for 2 high-quality RCT studies, the rest were methodologically flawed. Additional studies should be conducted using proper control groups, randomization, blinding, and validated disability outcome measures for pain and function. Until then, the results remain speculative because autologous whole-blood and PRP injection treatments are not standardized.

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