The aim of this randomized controlled trial study was to compare the effect of intra-articular injection of Hypertonic Dextrose Prolotherapy (HDP) with Normal Saline (NS) in the clinical improvement of knee osteoarthritis (KOA) patients with comorbid obesity. The main questions to be answered are:

• How does the effect of HDP versus NS intra-articular injection compare to the numerical rating score (NRS) in obese KOA patients?
• How does the effect of HDP versus NS intra-articular injection compare to scores of The Western Ontario and McMaster Universities Arthritis Index (WOMAC) in obese KOA patients?
• How does the effect of HDP versus NS intra-articular injection compare to the thickness of the femoral cartilage in obese KOA patients?

Participants who meet the inclusion and exclusion criteria will be randomized based on the order of the outpatient department each day, with odd numbers as the HDP intervention group and even numbers as NS. They received ultrasound-guided intra-articular injections on day 1 and day 30.

Researchers will compare HDP versus NS groups to see which group improves NRS, WOMAC, and femoral cartilage thickness.

This is a randomized controlled study, which recruited KOA patients with obese comorbidity who were treated at the Outpatient Department of Physical Medicine and Rehabilitation at Rumah Sakit Daerah Haji Provinsi Jawa Timur, Surabaya, Indonesia from May to August 2023. The participants were divided into two groups, including HDP versus NS injections.

Each study participant's identity including age, gender, weight, height, and BMI was recorded. Then an evaluation of the NRS, WOMAC score, and femoral cartilage thickness was carried out using ultrasound.

This study assessed using the NRS scale for pain reduction on a scale of 0 to 10 (0 means no pain, while 10 means very pain). The WOMAC Score consists of 24 questions with four scales, namely 0: none, 1: mild, 2: moderate, 3: severe, and 4: very severe. Femoral cartilage thickness scan using ultrasound with millimeter units.

Inclusion Criteria:

• Patient was diagnosed with knee osteoarthritis (KOA).
• Patient was diagnosed with obesity.

Exclusion Criteria:

• Patient with a history of knee trauma.
• Patient with a history of knee surgery.
• Patient with a history of intra-articular injection before.

Participants who met the eligibility of the study who were on outpatient treatment on that day were randomized in order of queue, odd numbers as the intervention group and even numbers as the control group.