summary A Tibial Eminence Fracture, also known as a tibial spine fracture, is an intra-articular fracture of the bony attachment of the ACL on the tibia that is most commonly seen in children from age 8 to 14 years during athletic activity. Diagnosis can be confirmed with radiographs of the knee. MRI studies can be helpful for determining associated ligamentous/meniscal damage. Treatment is closed reduction and casting or open reduction and fixation depending on the degree of displacement and success of closed reduction. Epidemiology Incidence 2-5% of knee injuries with effusion in the pediatric population Demographics most common in ages 8-14 Etiology Pathophysiology traumatic mechanism rapid deceleration or hyperextension/rotation of the knee, as in sports same mechanism that would cause ACL tear in adult fall from bike or motorcycle (typically resulting in hyperextension) Associated conditions occur in 40% of eminence fractures meniscal injury collateral ligament injury capsular damage osteochondral fracture Anatomy Osteology tibial eminence non-articular portion of the tibia between the medial and lateral tibial plateau Consists of two spines: ACL attaches to medial spine ACL insertion is 9mm posterior to the intermeniscal ligament and adjacent to anterior horns of meniscus PCL does not attach to tibia spines Pediatric specific Intercondylar eminence in incompletely ossified and is more prone to failure than ligamentous structures Failure occurs through deep cancellous bone Fracture usually confined to intercondylar eminence, but it may propagate to tibial plateau, medial is most common Ligaments anterior cruciate ligament inserts 10-14 mm behind anterior border of tibia and extends to medial and lateral tibial eminence Classification Modified Meyers and McKeever Classification Type I Nondisplaced (<3mm) Type II Minimally displaced with intact posterior hinge Type III Completely displaced Type III+ Type III fracture with rotation Type IV Completely displaced, rotated, comminuted Presentation Symptoms severe swelling and pain in the knee inability to bear weight Physical exam inspection immediate knee effusion due to hemarthrosis Knee usually in flexed position ROM often limited secondary to pain once pain is controlled, lack of motion may indicate login to view 2 more bullets positive anterior drawer Imaging Radiographs recommended views AP lateral login to view 1 more bullet intercondylar oblique login to view 1 more bullet CT useful for pre-operative planning used when fracture displacement cannot be determined by plain radiographs MRI better at determining associated ligamentous/meniscal damage than CT or radiographs Majority of fractures show no additional internal derangement (meniscus injuries) 15-37% of cases have associated intra-articular pathology Treatment Nonoperative closed reduction, aspiration of hemarthrosis, immobilization in full extension indications login to view 1 more bullet reduction technique login to view 1 more bullet immobilization login to view 3 more bullets Operative ORIF vs. all-arthroscopic fixation indications login to view 3 more bullets Techniques Closed Reduction aspiration when tense hemarthrosis is present, needle aspiration with the injection of lidocaine may help extend the knee reduction extend the knee to full extension or hyperextension to observe for fragment reduction immobilization cast is placed at 0 degrees of flexion cast in extension for 3-4 weeks confirmation lateral radiograph to confirm reduction, and then serial radiographs to observe maintenance of reduction CT or MRI may be used when the adequacy of reduction is unclear Arthroscopic fixation approach standard arthroscopic portals technique reduction login to view 4 more bullets fracture fixation login to view 20 more bullets post-operative care immobilize with cast in extension for 7-10 days and repeat radiographs to ensure no displacement login to view 1 more bullet early controlled range of motion length of limited weight bearing is controversial Open fixation same principles as arthroscopic Complications Loss of motion very common, especially loss of extension may be due to displaced fragment impinging on femoral notch Arthrofibrosis more common with surgical reconstruction concomitant ACL injury is an independent risk factor for the need to return to the OR for MUA Growth arrest from iatrogenic injury during surgery ACL laxity incidence 38-100%, more common in operatively treated knees Lachman's laxity may be noted compared to contralateral limb functional instability is uncommon Rate of ACL reconstruction following this injury is 15-25% Prognosis Overall prognosis is good with 85% returning to prior level of sport