Osteochondral Allograft for Unsalvageable Osteochondritis Dissecans in the Skeletally Immature Knee

Background: While an excellent option for osteochondral defects in the adult knee, fresh osteochondral allograft (FOCA) in the skeletally immature adolescent knee has been infrequently studied. Purpose: To compare radiographic and patient-reported outcomes (PROs) in skeletally mature and immature adolescents after FOCA in the knee for treatment of unsalvageable osteochondritis dissecans (OCD). Study Design: Cohort study; Level of evidence, 3. Methods: Included were 34 patients (37 knees) who underwent size-matched FOCA of the knee for unsalvageable OCD lesions. All patients were aged ≤19 years and had a minimum of 12 months of follow-up. Patient characteristics, lesion characteristics, reoperations, and PROs were evaluated and compared between patients with open physes (skeletally immature; n = 20) and those with closed physes (skeletally mature; n = 17). Graft failure was defined as the need for revision osteochondral grafting. Postoperative radiographs were analyzed at 1 year and the final follow-up for graft incorporation and classified as A (complete), B (≥50% healed), or C (<50% healed). Results: The mean patient age was 15.4 years (range, 9.6-17.6 years), and the mean follow-up was 2.1 years (range, 1-5.3 years). The mean graft size was 5.0 cm² and did not differ significantly between the study groups. Patients with open physes were younger (14.7 vs 16.2 years; P =.002) and more commonly male (80% vs 35%; P =.008). At the 1-year follow-up, 85% of immature patients and 82% of mature patients had radiographic healing grades of A or B. Patients with open physes were more likely to achieve complete radiographic union at 1 year (65% vs 15%; P =.007) and demonstrated better Knee injury and Osteoarthritis Outcome Score (KOOS) Daily Living (96.8 vs 88.5; P =.04) and KOOS Quality of Life (87.0 vs 56.8; P =.01) at the final follow-up. Complications were no different in either group, and graft failure occurred in only 1 skeletally mature patient with a trochlear lesion. Conclusion: FOCA treatment for unsalvageable OCD in the young knee may be expected to yield excellent early results. Despite the presence of open physes and immature epiphyseal osteochondral anatomy, equivalent or improved healing and PRO scores compared with those of skeletally mature patients may be expected.