Calcium-Phosphate Subchondroplasty Provides Durable 24-Month Pain Relief and >90% Surgery-free Survivorship for Tibiofemoral Bone Marrow Lesions in Mild-To-Moderate Knee Osteoarthritis: A Prospective Multicenter Study

Purpose To report 24-month clinical outcomes, surgery-free survivorship, and radiological variations after Calcium-Phosphate (CaP) Subchondroplasty (SCP) procedures in patients with symptomatic knee bone marrow lesions (BMLs) in the context of mild-to-moderate knee osteoarthritis (OA). Methods Adults with tibiofemoral BMLs (Kellgren–Lawrence [KL] 1–3) underwent CaP SCP using a standardized protocol. Prespecified outcomes were KOOS (primary: KOOS Pain), EQ-5D-5L, and pain NRS at baseline, 1, 3, 6, 12, and 24 months; surgery-free survivorship (Kaplan–Meier); and structural status by KL and MOAKS (available-case imaging). Analyses compared time points with paired tests and 95% CIs. Results Ninety-two knees were treated. KOOS Pain improved from 45.9 ± 14.3 preoperatively to 81.3 ± 18.1 at 24 months ( p < .0001). All other KOOS subscales improved from baseline to 24 months (all p < .0001) and pain NRS decreased from 6.8 ± 1.5 to 3.3 ± 2.6 ( p < .0001). Kaplan–Meier surgery-free survivorship was 97.7% (95% CI, 90.9–99.4) at 12 months and 91.5% (95% CI, 82.9–95.8) at 24 months; 7/92 knees (7.6%) underwent reoperation. KL distributions showed no significant change versus baseline at 12 months ( p = .5089) or 24 months ( p = .9801). MOAKS improved at 12 months ( p = .0435) but not at 24 months ( p = .2517) in the available MRI subset. No serious device-related adverse events were observed. Conclusion In BML-positive knees with KL 1–3 OA, SCP yielded large and durable improvements in pain, function, and health-related quality of life through 24 months, with >90% surgery-free survivorship and radiographic stability.