I’m reading various articles on-line about platelet-rich plasma therapy. I’ve had several key players on my basketball team get these treatments. I’m trying to figure out if they really work well enough to insist other injured players get the same treatment. I’m having some difficulty understanding what is meant when studies are deemed “low-quality” or “moderate evidence.” Help?

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 investigated is 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.

In a recently published article, 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.

In that study, 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. Randomized means patients are placed in different groups by random draw.

No one in the study knows what treatment they are actually receiving. Some patients will be randomly placed in the control group. This group receives an injection but the treatment is a placebo — usually a saline solution. 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 are lost during the follow-up, or there is 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.”

Often, when researchers look over a body of evidence, there is 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 can range in size from 10 to thousands of patients. Follow-up can be anywhere from hours to years. There can be differences in the way something like platelet-rich plasma is prepared among the studies. And the area of the body treated varies from shoulder to elbow, knee to lower leg, and spine.

Right now, there are some inconsistencies in study results so that PRP is not consistently being shown to be an effective treatment for bone and soft-tissue injuries. This may have more to do with the lack of standardization in study design and different way outcomes were measured. Based on current evidence, it is unclear that platelet-rich plasma is an effective treatment for orthopedic conditions.

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.