Effects of platelet-rich plasma on pain and muscle strength in patients with knee osteoarthritis

Osteoarthritis (OA) of the knee is a chronic degenerative disorder. Platelet-rich plasma (PRP) is known to enhance tissue healing at injury sites through modification of the biological microenvironment. None of the studies has investigated the effect of PRP in the patient with bilateral knee OA. Therefore in this study, the author demonstrated that the PRP treatment significantly improves pain, stiffness, and disability in patients with knee OA compared to usual saline treatment.  

No studies are present which involved the comparison of impacts of platelet-rich plasma (PRP) injection and placebo injection in treating bilateral knee osteoarthritis (OA) or evaluating muscle strength after PRP injection in the same patient.

A total of 20 patients with bilateral knee OA (40 knees) were selected and categorized into two treatment groups: saline and PRP group. PRP group involved a single intra-articular PRP injection in the left or right knees which chosen by a coin toss. Saline group involved a single intra-articular injection of normal saline in the contralateral knee of the same patient. Western Ontario and McMaster's Universities Osteoarthritis Index (WOMAC) was considered as the primary outcome and isokinetic test findings as the secondary outcomes. The assessment was done at baseline and 2 weeks, 1, 3 and six months postoperatively.

A significant decrease was noticed in the WOMAC-pain and -total scores by the PRP group as compared to the saline group. Also, the PRP group showed a considerably greater percentage of knee strength during a more extended follow-up period. However, the PRP group exhibited insignificant differences in muscle strength as compared to the normal saline.

The knee OA patients show significant improvement in pain, functional disability and stiffness than the normal saline group. Supplementary strength training is suggested to improve muscle strength.