Osteoarthritis (OA) affects 30.8 million Americans; over 54% of these patients are estimated to require joint replacement during their lifetime. A multi-center randomized trial was conducted to investigate the effects of amniotic suspension allograft (ASA) in comparison to saline and hyaluronic acid (HA). Within this study there was an option for rescue if there was inadequate pain relief with the index injection. The purpose of the current study was to examine the effects of rescue injections compared to the patient’s initial treatment.
200 patients from 12 sites were randomized 1:1:1 to either saline, HA, or ASA. Patients (blinded) received a single intra-articular injection and were followed for 12 months. At 3 months, patients who self-reported unacceptable pain were eligible to receive ASA (if their initial randomization was saline or HA). ASA patients who reported unacceptable pain were offered standard of care management (outside of the study). Rescued patients (n=94) were followed from rescue (new baseline) to 12 months post-rescue. Changes from baseline to 3 months follow-up (original) were compared to changes from rescue baseline to the 3-month rescue visit using Knee Injury and Osteoarthritis Outcome Score (KOOS) and Visual Analog Scale (VAS). Statistical comparisons were made using LSMEANS with p-values from PROC MIXED.
Patients who were rescued with ASA had significantly greater improvements in KOOS pain scores (original Δ 4.62, rescue Δ 12.29; p=0.0044) and ADL scores (original Δ 5.55, rescue Δ 10.94; p=0.0432) compared to their original treatment course (saline or HA). Furthermore, rescued patients had significantly greater improvements in VAS pain with a rescue injection (original Δ -9.44, rescue Δ -27.26; p=0.0064).
Patients who received a rescue injection of ASA showed significantly greater improvements compared to their initial treatment. This data provides evidence for the potential use of ASA in the treatment of knee OA symptoms.