RESUMEN
OBJECTIVE: To systematically review the available clinical evidence regarding the safety and efficacy of knee intraosseous injections for the treatment of bone marrow lesions in patients affected by knee osteoarthritis. DESIGN: A literature search was carried out on PubMed, Embase, and Google Scholar databases in January 2020. The following inclusion criteria were adopted: (1) studies of any level of evidence, dealing with subchondral injection of bone substitute materials and/or biologic agents; (2) studies with minimum 5 patients treated; and (3) studies with at least 6 months' follow-up evaluation. All relevant data concerning clinical outcomes, adverse events, and rate of conversion to arthroplasty were extracted. RESULTS: A total of 12 studies were identified: 7 dealt with calcium phosphate administration, 3 with platelet-rich plasma, and 2 with bone marrow concentrate injection. Only 2 studies were randomized controlled trials, whereas 6 studies were prospective and the remaining 4 were retrospective. Studies included a total of 459 patients treated with intraosseous injections. Overall, only a few patients experienced adverse events and clinical improvement was documented in the majority of trial. The lack of any comparative evaluation versus subchondral drilling alone is the main limitation of the available evidence. CONCLUSIONS: Knee intraosseous injections are a minimally invasive and safe procedure to address subchondral bone damage in osteoarthritic patients. They are able to provide beneficial effects at short-term evaluation. More high-quality evidence is needed to confirm their potential and to identify the best product to adopt in clinical practice.