Percutaneous autologous bone marrow concentrate for knee osteoarthritis: patient-reported outcomes and progenitor cell content.

PURPOSE: Knee osteoarthritis (OA) is a common, progressively debilitating joint disease, and the intra-articular injection of autologous bone marrow concentrate (BMC) may offer a minimally invasive method of harnessing the body's own connective tissue progenitor cells to counteract accompanying degenerative effects of the disease. However, the extent to which the progenitor cell content of BMC influences treatment outcomes is unclear. We sought to determine whether patient-reported outcome measures associated with BMC treatment for knee OA are related to the concentration of progenitor cells provided. METHODS: In the present study, 65 patients (72 knees) underwent treatment for knee OA with autologous BMC and self-reported their outcomes for up to one year using follow-up questionnaires tracking function, pain, and percent improvement. A small fraction of each patient's BMC sample was reserved for quantification with a haematological analyzer and cryopreserved for subsequent analysis of potential connective tissue progenitor cells using a colony-forming unit fibroblast (CFU-F) assay. RESULTS: Patients reported significant increases in function and overall percent improvement in addition to decreases in pain relative to baseline levels following treatment with autologous BMC that persisted through 12 months. Patients reporting improved outcomes (46 of 72 knees) received BMC injections having higher CFU-F concentrations than non-responding patients (21.1×103 ± 12.4×103 vs 14.3×103 ± 7.0 x103 CFU-F per mL). A progenitor cell concentration of 18×103 CFU-F per mL of BMC was found to best differentiate responders from non-responders. CONCLUSION: This study provides supportive evidence for using autologous BMC in the minimally invasive treatment of knee OA and suggests that increased progenitor cell content leads to improved treatment outcomes. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03011398, 1/7/17.

The rate of venous thromboembolism after knee bone marrow concentrate procedures: should we anticoagulate?

PURPOSE: Intra-articular injections of autologous, minimally manipulated, cell therapies such as bone marrow concentrate (BMC) to treat knee osteoarthritis (OA) may delay or prevent future total knee arthroplasty (TKA). Arthroplasty has the known and substantial risk of venous thromboembolism (VTE) and requires routine prophylaxis, whereas the VTE risk associated with knee BMC injections is unknown. We report on the rate of VTE from a large orthobiologics patient registry and assess whether knee BMC procedures require routine prophylaxis. METHODS: A retrospective analysis of knee osteoarthritis cases tracked in a treatment registry and treated at 72 clinical sites with BMC from 2007 to 2020 who were not prophylactically anticoagulated was performed to identify adverse events (AEs) associated with VTE. Treating physicians were contacted to improve discovery of possible occurrences of VTE. RESULTS: Twenty cases (0.16%) of VTE were identified from the registry of 12,780 knee BMC treatments. These events were less frequent than the published data demonstrate for anticoagulated TKA patients. CONCLUSION: Based on the rates of VTE from our retrospective treatment registry analysis compared to the risk of medication-induced haemorrhage, routine prophylactic anticoagulation is not recommended for intra-articular knee BMC procedures. Further research into safety and efficacy of BMC treatment for knee OA is warranted. CLINICAL TRIAL IDENTIFIER: NCT03011398, retrospectively registered.