Summary

A combined strategy of intra-articular injection of HT and one week later PRP+HA can resolve quickly the symptoms of advanced knee OA, but with equal efficacy than early knee OA at 12 months follow-up.

Abstract

Background

Osteoarthritis (OA) is one of the major causes of knee pain and is detrimental to quality of life. Intra-articular injections of platelet-rich plasma (PRP) and hyaluronic acid (HA) can be used to try to delay the need for knee arthroplasty.

Purpose

To evaluate the efficacy of a treatment strategy combining an intra-articular injection of triamcinolone hexacetonide (TH) followed one week later by combined intra-articular injection of PRP+HA, comparing between knees with early knee OA and those with advanced knee OA.

Methods

Prospective case series study that included adult patients (> 45 years old) with symptomatic and radiographic knee OA. Exclusion criteria comprised previous knee surgery, diagnosis of autoimmune or platelet diseases, non-steroid anti-inflammatory drugs three days prior to injection or history of repeated use of corticosteroids. The grade of knee OA was established with the Kellgreen-Lawrence and divided into early (grades I/II) and advanced (grades III/IV). A total of 51 patients with diagnosis of knee OA were included (n=17 with early OA; n=34 with advanced OA). Patients’ demographics (age, sex and body mass index) were homogenous at baseline between groups. Patients first received an intra-articular injection of 40 mg of TH to decrease local inflammatory response. The following week, patients received combined intra-articular injections of PRP and HA (consecutive injections, but one at time and not mixed in the same injection). The PRP was obtained from 54 mL sample of venous blood and centrifuged at 2400 rpm for 8 minutes. The suspended concentration of PRP was carefully extracted using a pipette to avoid aspiration of leukocytes from the buffy coat (leukocyte-poor PRP). It was injected 8 ml of PRP into the knee. The HA product consisted on 20 mL of low-weight HA. Patient-reported outcomes were evaluated at baseline and 2, 6 and 12 months by the Visual Analogue Scale (VAS) and the Knee injury and Osteoarthritis Outcome Score (KOOS). Withing-group differences were evaluated with the Wilcoxon test and between-groups differences with the Mann-Whitney test.

Results

At baseline, knee with advanced OA displayed worse impairments in KOOS-ADL (36.0 ± 21.1 vs 50.3 ± 25.5, P=0.45) and KOOS-Sports (7.4 ± 10.9 vs 14.7 ± 12.7, P=0.23); all other outcomes were homogenous at baseline (P>0.05). Both groups showed a significant improvement in all outcomes at 2 months follow-up (P<0.05). The improvement was significantly superior in the advanced knee OA in most of KOOS domains (P<0.05), except for the KOOS-Sports (P= 0.233). However, at 6 months, knees with advanced knee OA showed a significantly worsening of results for KOOS-Pain, KOOS-symptoms and KOOS-ADL domains and KOOS total score as compared to those with early knee OA (P<0.05). At 12 months, the improvement was not statistically significant between groups for any of the outcomes evaluated (P>0.05).

Conclusion

A combined strategy of intra-articular injection of HT and one week later PRP+HA displays a more significant improvement of patient-reported outcomes at two months in knees with advanced OA, but which leveled out with those with early OA at 6 months, without significant differences at 12 months follow-up.