Injectable Amniotic Membrane/Umbilical Cord Particulate for Knee Osteoarthritis: A Prospective, Single-Center Pilot Study

Abstract

Objective: To evaluate the short-term safety and effectiveness of amniotic membrane/umbilical cord particulate (AMUC) in managing pain in patients with various severities of knee osteoarthritis (OA).

Design: Single-center, prospective, investigator-initiated pilot study.

Setting: Private practice.

Subjects: A total of 20 knee OA patients aged ≥18 years were enrolled with pain >40 mm, as determined by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)-A.

Methods: Patients received an ultrasound-guided, intra-articular injection of 50 mg of AMUC particulate reconstituted in 2 mL of preservative-free saline. All patients were then monitored at six weeks, 12 weeks, and 24 weeks postinjection. Patients who did not show >30% reduction in pain received a second injection of AMUC at six weeks. WOMAC, Patient Global Assessment, medication usage, and magnetic resonance imaging (MRI) were assessed.

Results: Knee OA pain significantly decreased from 74.3 ± 17.2 at baseline to 45.0 ± 25.4 at six weeks (P < 0.01), 35.4 ± 26.6 at 12 weeks (P < 0.001), and 37.4 ± 26.7 at 24 weeks (P < 0.001). This pain reduction was associated with a significant improvement in physical function (WOMAC-C) at all time points (P < 0.05) and stiffness (WOMAC-B) at 12 weeks (P = 0.01). Eleven patients received a second injection, which was significantly correlated with body mass index >30 kg/m2 (P = 0.025). MRI evaluation of the overall population revealed an improvement in the severity of bone marrow lesions in seven patients. No adverse events were observed.

Conclusions: AMUC particulate injection relieved pain and improved physical function in patients with symptomatic knee OA.

Keywords: Amniotic Membrane; Knee Joint Pain; Orthopedics; Osteoarthritis; Treatment Outcome; Umbilical Cord; WOMAC.

Figure 1

Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) subscale scores over 24 weeks following intra-articular injection of amniotic membrane/umbilical cord particulate. WOMAC-A pain scores (expressed as mean ± SD in mm) (A), WOMAC-C physical function (B), WOMAC-B stiffness (C), and WOMAC global (D) are plotted against time. All data points were compared with baseline. *P < 0.05; **P ≤ 0.01; ***P ≤ 0.001.

Figure 2

Patient Global Assessment. Patient’s evaluated how osteoarthritis affected them since their last follow-up visit. Seventeen of 20 patients reported positive improvement at six and 12 weeks. By 24 weeks, this number decreased to 14 patients, with hypertension being a significant covariate (P = 0.01).

Figure 3

Change in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores from baseline according to body mass index (BMI). A) WOMAC-A pain scores, (B) WOMAC-C physical function scores, (C) WOMAC-B stiffness scores, and (D) WOMAC global scores are plotted against time for patients with BMI <30 kg/m² (solid line, N = 12) and those with BMI ≥30 kg/m² (dashed line, N = 8). **P ≤ 0.01.