Risks and Benefits of Blood Injection Therapy

Any time a new treatment technique is tried approval depends on how well it works, long the effects last, and the balance between risks and benefits. Risks usually include problems during the procedure and complications after the treatment. One of the new treatments for orthopedic conditions currently being studied is called platelet-rich plasma or blood injection therapy.

Platelet-rich plasma (PRP) is a medical treatment being used for a wide range of musculoskeletal problems. Platelet-rich plasma refers to a sample of serum (blood) plasma that has as much as four times more than the normal amount of platelets. Once activated in response to an injury, platelets release active proteins and growth factors. This treatment enhances the body’s natural ability to heal itself and is used to improve healing and shorten recovery time from acute and chronic soft tissue injuries.

PRP has been used for years after plastic surgery and surgery on the mouth, jaw, and neck. It seems to promote bone graft healing. Researchers have found a way to combine this substance with other chemicals to make it into a putty or gel that can be painted on a surgical site to speed up healing.

Blood injection therapy of this type has been used for knee osteoarthritis, degenerative cartilage, spinal fusion, bone fractures that don’t heal, and poor wound healing. This treatment technique is fairly new in the sports medicine treatment of musculoskeletal problems, but gaining popularity quickly.

The clinical benefit for acute injuries, chronic musculoskeletal problems, and even degenerative conditions is being studied in many areas across the United States and Canada. In this meta-analysis, researchers from the Center for Evidence-Based Orthopaedics at McMaster University in Canada report on the efficacy (benefits) of platelet-rich plasma use for a variety of orthopedic conditions.

A meta-analysis means a large number of studies with small-to-medium numbers of participants are combined or pooled together. This method increases the n (number of patients involved) and allows for more meaningful statistical results. Sometimes smaller studies are high-quality but without the necessary number of patients involved, the results are limited in providing evidence that a treatment (such as PRP) is beneficial.

The authors provide a very nice summary describing how studies are evaluated for quality of evidence. For example, randomized, controlled trials are usually the highest quality. Patients are placed in different treatment and control groups by random draw. No one in the study knows what treatment they are actually receiving. In a double-blind study, even the physicians giving the treatments don’t know what treatment each patient is getting.

Studies are “downgraded” in quality when there is a lack of blinding, large numbers of patients lost during the follow-up, or an early stop of the study for any reason. Studies can be upgraded or downgraded depending on how well matched the subjects are in terms of age and similarities or differences in the physical condition being studied. Quality of evidence can also be downgraded if there are large discrepancies between studies. And the quality of evidence can be graded as high, moderate, low, or very low.

When studies use different ways of measuring outcomes, it becomes more difficult to compare the results. When the outcomes are inconsistent among the participants (some get betters, others don’t or some get a little better while others are much better), then results are considered “imprecise” or “uninformative.”

In this study, an attempt was made to combine studies using autologous blood (the patient’s own blood) to treat an orthopedic injury. The studies had to be randomized or prospective (patients are studied as the treatment is given) and there had to be a control group. The control group did not receive the platelet-rich plasma treatment but a placebo or pretend solution. The main measure of benefit (efficacy) was pain using a specific tool to measure pain (the Visual Analog Scale or VAS).

The group of researchers did a thorough search of the literature for published studies, unpublished studies, presentations at professional meetings and abstracts presented at annual meetings of orthopedic societies.

They found 895 articles on the subject but only 33 studies that qualified to be included. There was a general lack of standardization among the studies reviewed. This means the way the studies were conducted was different enough to create problems in comparing results (like comparing apples to oranges — both fruit but different colors, tastes, and textures).

For example, studies ranged in size from 10 to 165 patients. Follow-up was a broad ranged from five days to two years. A closer look at the studies also showed there were differences in the way platelet-rich plasma was prepared among the studies. And the area of the body treated varied from shoulder to elbow, knee to lower leg, and spine.

In terms of pain control and improved function as a result of decreased pain, only six studies showed a benefit of the platelet-rich plasma (PRP) injection. One study even showed the control group had the best results. The remaining studies could not show a benefit of PRP over placebo.

The inability to conclude that PRP is an effective treatment for bone and soft-tissue injuries may have more to do with the lack of standardization in study design and different way outcomes were measured. As a result, the authors summarize by saying the evidence is unclear that platelet-rich plasma is an effective treatment for orthopedic conditions.

They suggest future high-quality studies are needed to identify best use of PRP (acute traumatic lesions, chronic conditions, degenerative diseases). It will be important to uncover risks of this treatment approach and weigh the benefits against the risks for each condition.

Future studies also need to have good design with high-grade evidence and measurable outcomes that can be compared from study to study. Follow-up should be long enough to tell if there is a long-term benefit to patients. And there needs to be a focus on the different results obtained based on various ways blood is processed to create platelet-rich plasma.