Subchondroplasty for the Treatment of Post-Traumatic Bone Marrow Lesions of the Medial Femoral Condyle in a Pre-Clinical Canine Model

This study characterizes long-term outcomes associated with subchondroplasty (SCP) treatment for impact-induced subchondral bone marrow lesions (BML) using a validated pre-clinical canine model.

With IACUC approval, purpose-bred research hounds (n = 16) underwent arthroscopic impact injury (40N) to both medial femoral condyles. At 3 months, functional assessments, arthroscopy and MRI were performed and knees (n = 32) were randomly assigned to SCP (3 mL fluoroscopically guided percutaneous injection of AccuFill BSM into BML bone defects) or sham injection (Control). Dogs were assessed at 3, 6, 12, and 24 months after treatment using functional assessments, radiographic evaluation, arthroscopy, and MRI. Dogs were humanely euthanatized at 3, 6, 12, or 24 months after treatment for gross, microCT, and histologic assessments.

All knees had focal articular cartilage defects with associated subchondral BMLs, as well as clinical dysfunction, 3 months after injury. At the 3- and 6-months, SCP knees showed more functional impairment than Control knees, however, these differences were not statistically significant. At 1 and 2 years post-treatment, function in SCP knees was better than in Control knees with range of motion being significantly (p < 0.05) better for SCP. Radiographic, arthroscopic, MRI, gross, microCT, and histologic findings matched the functional assessments well with Control being associated with better results at the 2 early time points and SCP being associated with better results at 1 and 2 years.

CLINICAL SIGNIFICANCE: SCP treatment using calcium phosphate bone void filler was associated with an initial increase in pain and dysfunction followed by symptomatic benefits for up to 2 years after treatment for post-traumatic femoral condyle BMLs in a preclinical canine model. This article is protected by copyright. All rights reserved.