Total Knee Conversion Rates and Functional Outcome After Calcium Phosphate Injection for Bone Marrow Lesions of the Knee.

Untreated osteoarthritis (OA)-related bone marrow lesions (OA-BML) can hasten the progression of knee OA. Previous studies have shown that fluoroscopically guided intraosseous calcium-phosphate (CaP) injections of OA-BML during knee arthroscopy can lead to pain reduction, improved functionality, and prolonged time until conversion to total knee arthroplasty (TKA). The purpose of this retrospective study is to compare the clinical outcomes of patients who underwent knee arthroscopy and CaP injection for OA-BML versus knee arthroscopy for non-OA-BML pathologies. Two-year follow-up data and patient-reported outcomes including knee injury and operative outcome scores, joint replacement scores (KOOS, JR) were available for 53 patients in the CaP group and 30 patients in the knee arthroscopy group. Results indicate that patients in the CaP group had less frequent conversion to TKA compared with patients in the knee arthroscopy group. Statistical analysis demonstrated a statistical difference between preoperative and postoperative KOOS, JR within the CaP group but not for the knee arthroscopy group. Two-year postoperative KOOS, JR for CaP patients was statistically greater than the 2-year postoperative KOOS, JR of knee arthroscopy patients. Results indicate greater improvement in functional outcomes with knee arthroscopy and CaP injection of OA-BML compared with knee arthroscopy alone for non-OA-BML diagnoses. The results of this retrospective study help to distinguish the benefits of knee arthroscopy accompanied by CaP intraosseous injection from that of knee arthroscopy alone.