Platelet-rich plasma (PRP) appeared to improve the healing of patellar tendon graft sites after anterior cruciate ligament (ACL) reconstruction, Brazilian researchers say.

But the intervention didn't have any clinical impact. Dr. Adriano Marques de Almeida, who led a recent trial, told Reuters Health by email, "I think that PRP is a promising therapy for sports injuries. However, more studies are needed to clarify the specific indications of this therapy."

Dr. Almeida and colleagues at Sao Paulo University Medical School note in their report that other teams have had mixed results with PRP. But Dr. Almeida said an Italian clinical study, and research in rabbits, suggests that PRP reduces morbidity at the patellar tendon harvest site.

The heterogeneity of sports injury lesions can make them difficult to compare in prospective randomized trials. The authors chose the patellar tendon for their model because it's often used as a graft donor site for ACL reconstruction, and the procedure creates a standard and well-defined defect.

As reported online April 2nd in The American Journal of Sports Medicine, the researchers randomly assigned 27 patients to receive or not receive PRP in the patellar tendon harvest site during ACL reconstruction.

On the first postoperative day, patients in the PRP group reported less pain on a visual analogue scale (3.8 vs 5.1, p=0.02). And at six months, patellar tendon healing, as assessed by the gap (defect) area, was significantly better in the PRP group (4.9 vs 9.4 mm2; p=0.046).

There were no differences between the groups, however, in responses to knee function questionnaires or in isokinetic testing results at six months.

The researchers say that while the study was small, the approach appears to reduce postoperative pain and improve healing. Nevertheless, they concede, "we were not able to find any difference in the outcome of the procedure."

Am J Sports Med 2012. Abstract

David Douglas • Reuters Health Information © 2012