OUTCOMES OF BIOABSORBABLE FIXATION OF OSTEOCHONDRAL INJURIES IN THE PEDIATRIC AND ADOLESCENT KNEE

Abstract

Background: Osteochondral lesions (OCL), including osteochondritis dissecans (OCD) and traumatic osteochondral fractures (OCF), are often encountered when treating injuries affecting the pediatric and adolescent knee. There are an array of treatment options depending upon lesion size, location, chronicity, and equally important, surgeon experience. There is a potential for healing in children and adolescents that may not be present in adults and the intent of internal fixation is to reduce and restore the injured hyaline cartilage and underlying bone. Stable fixation utilizing bioabsorbable implants offers a possibility of OCL healing without the need for implant removal or a major restorative procedure such as an osteochondral autograft transfer, osteochondral allograft, or autologous chondrocyte implantation, therefore avoiding the associated costs and potential morbidity. The purpose of our study was to review the mid-term outcomes of internal fixation with bioabsorbable implants of osteochondral injuries of the knee in children and adolescents. Methods: An IRB approved retrospective review of patients younger than 18 years old who had internal fixation of knee OCLs with bioabsorbable implants was performed. All those included had a minimum 2-year follow-up and completed validated outcome scores (Pedi-IKDC, Tegner, Lysholm). Medical records were reviewed from 2009 to 2015 for patient demographics, intraoperative details, and postoperative outcomes. Pedi-IKDC and Tegner-Lysholm functional outcome scores were used to assess overall outcomes at final follow-up. Return to the operating room was recorded. All cases were performed at a single tertiary pediatric institution by a single pediatric fellowship trained orthopedic surgeon. Results: There were a total of 35 children and adolescents that had a knee OCL that underwent internal fixation with bioabsorbable implants. 7 patients were lost to follow-up with a final cohort of 28 of the 35 patients (80%). Average follow-up was 44 months (range 24-97 months). Average age was 14.7 years. Out of the 28 children, 14 had OCD and 14 OCFs. The average number of bioabsorbable darts and screws used per intervention was 2 and 1, respectively. The average Pedi-IKDC and Lysholm scoring at final follow-up was 89.5 and 91, respectively. Five patients returned to the operating room following the primary procedure: 2 for manipulation under anesthesia related to OCL fixation, 1 for a planned staged ACL reconstruction, 1 for MPFL reconstruction for recurrent patella instability following the index procedure, and 1 patient returned secondary to a proud implant that was in-turn debrided. None of the 28 patients underwent a revision cartilage procedure. Conclusion: The use of bioabsorbable implants (screws and darts) in children and adolescents appears to be a safe and efficacious treatment with good functional outcomes at mid-term follow up and in this cohort there was no need for a revision cartilage procedure. Larger multi-center longer-term follow studies are needed.