Background: Dextrose injection is reported to improve KOA-related clinical outcomes, but its effect on articular cartilage is unknown. A chondrogenic effect of dextrose injection has been proposed.
Objective: To assess biological and clinical effects of intra-articular hypertonic dextrose injections (prolotherapy) in painful knee osteoarthritis (KOA).
Design: Case series with blinded arthroscopic evaluation before and after treatment.
Setting: Physical medicine and day surgery practice.
Participants: Symptomatic KOA for at least 6 months, arthroscopy-confirmed medial compartment exposed subchondral bone, and temporary pain relief with intra-articular lidocaine injection.
Intervention: Four to six monthly 10 mL intra-articular injections with 12.5% dextrose.
Main outcome measures: Visual cartilage growth assessment of 9 standardized medial condyle zones in each of 6 participants by three arthroscopy readers masked to pre/post injection status (total 54 zones evaluated per reader); biopsy of a cartilage growth-area post-treatment, evaluated using H&E and Safranin-O stains, quantitative polarized light microscopy, and immunohistologic cartilage typing; self-reported knee specific quality of life using the Western Ontario McMaster University Osteoarthritis Index (WOMAC, 0-100 points).
Results: Six participants (1 female) with median age of 71, WOMAC composite score of 57.5 points and a 9-year pain duration received a median 6 dextrose injections and follow-up arthroscopy at 7.75 (4.5-9.5) months. In 19 of 54 zone comparisons all three readers agreed that the post-treatment zone showed cartilage growth compared with the pre-treatment zone. Biopsy specimens showed metabolically active cartilage with variable cellular organization, fiber parallelism, and cartilage typing patterns consistent with fibro- and hyaline-like cartilage. Compared with baseline status, the median WOMAC score improved 13 points (p=.013). Self-limited soreness after methylene-blue instillation was noted.
Conclusions: Positive clinical and chondrogenic effects were seen after prolotherapy with hypertonic dextrose injection in symptomatic grade IV KOA participants suggesting disease-modifying effects and the need for confirmation in controlled studies. Minimally invasive arthroscopy (single-compartment, single-portal) enabled collection of robust intra-articular data.