Intra-articular Physeal Fractures of the Distal Femur: A Frequently Missed Diagnosis in Adolescent Athletes.

BACKGROUND: Intra-articular physeal fractures of the distal femur are an uncommon injury pattern, with only a few small case series reported in the literature. PURPOSE: To pool patients from 3 high-volume pediatric centers to better understand this injury pattern, to determine outcomes of surgical treatment, and to assess risk factors for complications. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A multicenter retrospective review of all patients presenting with an intra-articular physeal fracture between 2006 and 2016 was performed. Patient demographic and injury data, surgical data, and postoperative outcomes were documented. Radiographs were evaluated for fracture classification (Salter-Harris), location, and displacement. Differences between patients with and without complications were compared by use of analysis of variance or chi-square tests. RESULTS: A total of 49 patients, with a mean age of 13.5 years (range, 7-17 years), met the inclusion criteria. The majority of fractures were Salter-Harris type III fractures (84%) involving the medial femoral condyle (88%). Football was responsible for 50% of the injuries. The initial diagnosis was missed in 39% of cases, and advanced imaging showed greater mean displacement (6 mm) compared with radiographs (3 mm). All patients underwent surgery and returned to sport with "good to excellent" results after 2 years. Complications were more common in patients with wide-open growth plates, patients with fractures involving the lateral femoral condyle, and patients who were casted (P < .05). CONCLUSION: Clinicians evaluating skeletally immature athletes (particularly football players) with acute knee injuries should maintain a high index of suspicion for an intra-articular physeal fracture. These fractures are frequently missed, and advanced imaging may be required to establish the diagnosis. Leg-length discrepancies and angular deformities are not uncommon, and patients should be monitored closely. Surgical outcomes are good when fractures are identified, with high rates of return to sport.