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One injection with 10-times the normal concentration of leukocyte- free platelet-rich plasma is as effective as two injections of platelet-rich plasma for patients with knee osteoarthritis, according to results of a recently published study.
“A single injection of white-blood-cell-filter platelet-rich plasma (PRP) in concentrations 10-times normal helps in early osteoar- thritis and can be beneficial in well-selected patients,” study author Mandeep S. Dhillon, MS, FAMS, of the Post Graduate Institute of Medical Education and Research, in Chandigarh, India, told Or- thopaedics Today Europe.

Dhillon and colleagues compared the outcomes of three treat- ment groups:

• a single-injection group (26 patients);
• a group who received two injections of PRP 2 weeks apart (25 patients); and
• 23 patients in a placebo group injected with normal saline.

Study excluded key interventions

The study consisted of 53 women and 22 men with an average age of 53 years. Inclusion criteria were patients with bilateral Ahl- bäck grade 1 or 2 osteoarthritis. Dhillon and colleagues excluded patients who had medical comorbidities or recent interventions that could influence the effect of treatment. Patients were followed up at 6 weeks, 3 months and 6 months.
The placebo group’s outcomes did not improve during the follow-up.
The single- and double-injection groups showed similar im- provements in WOMAC scores at early follow-up, but the results declined later on.

“The effect lasted for a short period, 6 months,” Dhillon said in an interview. “However, the effects tended to taper off over time. We feel that there is a need for longer follow-up.”
The total WOMAC score for the single-injection group decreased from 49.86 points at baseline to 27.18 points at final follow-up. Base- line scores for pain (10.2 points), stiffness (3.1 points) and physical function (36.5 points) also decreased at final follow-up to 5.0, 2.10, and 20.8 points, respectively.
In the double-injection group, baseline WOMAC scores for pain (10.6 points), stiffness (3.5 points), physical function (39.1 points) and total score (53.2 points) were 6.2 points, 1.9 points, 22.4 points and 30.5 points, respectively, at final follow-up.
The researchers noted minor complications, such as syncope, dizziness, headaches, sweating and tachycardia in six patients in the single-injection group and 11 patients in the double-injection group. The complications lasted a short time and did not affect treatment, outcome or discharge, Dhillon said. Some patients in the double-in- jection group experienced these complications only after the second injection. The researchers also noted residual pain or stiffness for 48 hours after treatment in four patients in the single-injection group and three patients in the double-injection group.

“We have postulated that a higher platelet concentration in these cases may have been responsible for these adverse effects, but cannot prove this,” Dhillon said. “However, these adverse events were mild and uncommon, and do not seem to influence the safety or efficacy of the procedure.”
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