A study depicted that for combating mild to moderate knee osteoarthritis, the intra-articular use of APS was safe. A substantial pain improvement was documented three years after using a single injection.

A randomized double-blind saline-controlled multicenter case series was conducted to explore if the favorable therapeutic effects of a single intra-articular injection of APS in patients suffering from knee osteoarthritis previously documented at one year in a randomized, double-blind, multicenter, saline-controlled study last up to three years.

This study recruited 46 patients suffering from Kellgren-Lawrence 2 or 3 knee osteoarthritis. Participants were randomly divided into two cohorts: (a) One saline injection (n = 15), and (b) One ultrasound-guided APS injection (n = 31). At one year, the saline group was permitted to cross over.

At 24 and 36 months, the participants were reexamined utilizing the following parameters: (a) 36-Item Short-Form Health Survey (SF-36) (b) visual analog scale for pain (VAS), (c) Knee injury and Osteoarthritis Outcome Score (KOOS), (d) Outcome Measures in Rheumatology–Osteoarthritis Research Society International (OMERACT-OARSI) responder rate, and (e) Western Ontario and McMaster Universities Osteoarthritis Index Likert 3.1 (WOMAC LK 3.1).

Magnetic resonance imaging (MRI) assessment was carried out using the MRI Osteoarthritis Knee Score (MOAKS) prior to and at 24 months after therapy. The radiographs were evaluated per Kellgren-Lawrence before and every year after therapy.

In the APS cohort, an improvement was observed in WOMAC, KOOS, and VAS pain scores at 1 year and 3 years, as depicted in the following table:

Data is presented as mean ± standard deviation

From 12 to 36 months, the VAS pain score considerably deteriorated. All participants in the saline cohort agreed to cross over to APS. Compared to baseline, their final scores improved. However, there was not much improvement compared to the crossover point.

Notably, 28.6% (4/14) crossover cases and 26.9% (7/26) APS cases were regarded failures as the subjects underwent additional injective therapies or surgical interventions between the 12-month and 36-month follow-ups. The results of MOAKS depicted no vital variations.

In patients with better cartilage, a better clinical alleviation of pain was seen when their baseline scores were not good. However, it was found to be reversed in the case of patients having cartilage loss at baseline. Thus, APS injections are safe and considerably alleviates pain in patients having knee osteoarthritis.