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-year 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 two 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. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2709-2717, 2018.
Keywords: bone marrow lesions; bone void filler; canine model; post-traumatic osteoarthritis; subchondroplasty.
© 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.