Overview
Definition:
Tibial spine fractures, also known as tibial plateau fractures or anterior cruciate ligament (ACL) avulsion fractures, involve an avulsion of the tibial spines (intercondylar eminence) from the tibial plateau
This is often caused by forceful anterior translation of the femur on a flexed tibia, leading to traction on the ACL insertion
These fractures are a common intra-articular knee injury in children and adolescents.
Epidemiology:
Tibial spine fractures account for approximately 2-13% of all pediatric knee injuries
They are most common in children aged 8-14 years, with a bimodal distribution mirroring ACL injury patterns in adults
There is a higher incidence in males, likely due to increased participation in sports
Associated injuries, particularly to the meniscus and collateral ligaments, are common.
Clinical Significance:
Accurate diagnosis and management of tibial spine fractures are crucial to prevent long-term sequelae such as knee stiffness, chronic pain, instability, post-traumatic arthritis, and impaired quadriceps function
Early recognition and appropriate treatment can significantly improve functional outcomes and reduce the risk of debilitating knee issues in pediatric patients.
Clinical Presentation
Symptoms:
Immediate onset of severe knee pain
Inability to bear weight on the affected leg
Swelling around the knee
A sensation of popping or tearing at the time of injury
Mechanical symptoms like locking or catching of the knee
A feeling of instability or giving way.
Signs:
Effusion of the knee joint, often significant
Tenderness to palpation over the tibial plateau, particularly anteriorly
Limited range of motion, especially extension
Positive Lachman and anterior drawer tests, though these may be less reliable in acute injury due to pain and guarding
Palpable step-off over the tibial spines in displaced fractures
Ecchymosis may develop later.
Diagnostic Criteria:
Diagnosis is primarily based on clinical suspicion and confirmed with imaging
The presence of acute knee trauma, inability to bear weight, and tenderness over the tibial spines are key clinical indicators
Radiographic evidence of a displaced or non-displaced fracture fragment at the ACL insertion site on plain radiographs or CT scan establishes the diagnosis.
Diagnostic Approach
History Taking:
Detailed mechanism of injury is essential, focusing on the position of the knee and the forces applied
Ask about any preceding trauma or previous knee injuries
Inquire about the onset and character of pain, swelling, and any mechanical symptoms
Assess the child's activity level and participation in sports
Red flags include inability to bear weight, significant effusion, and suspicion of neurovascular compromise.
Physical Examination:
Begin with inspection for swelling, ecchymosis, and gross deformity
Assess for limb length discrepancies
Palpate for tenderness over the tibial plateau, patellar tendon, collateral ligaments, and hamstring tendons
Evaluate range of motion (flexion and extension), noting any limitations and pain
Perform ligamentous stability tests cautiously: anterior drawer, Lachman, valgus and varus stress tests
Evaluate for meniscal signs like McMurray's test
Assess distal neurovascular status (pulses, sensation, motor function).
Investigations:
Radiographs: Standard AP, lateral, and oblique views of the knee are typically the initial imaging modality
They are often sufficient to diagnose displaced fractures but may miss nondisplaced or minimally displaced fragments
CT scan: Provides detailed visualization of the fracture fragment, its displacement, and comminution, which is crucial for surgical planning
MRI: Useful for evaluating associated soft tissue injuries such as meniscal tears, ligamentous injuries, and chondral damage, especially when clinical suspicion is high for these injuries
However, it is not the primary modality for diagnosing the fracture itself.
Differential Diagnosis:
Other pediatric knee injuries: Meniscal tears
Ligamentous injuries (ACL, PCL, MCL, LCL)
Osteochondral fractures
Patellar dislocations
Pediatric tibial eminence avulsion fractures
Traumatically induced physeal fractures
Stress fractures
Tumorous lesions (rare).
Management
Initial Management:
Pain control with analgesics
Immobilization in a knee immobilizer or cast in extension or slight flexion to reduce strain on the ACL
Application of ice packs to reduce swelling
Non-weight bearing status on the affected limb
Elevation of the limb to minimize edema
Urgent orthopedic consultation is mandatory for all suspected tibial spine fractures.
Medical Management:
Primarily focused on pain and inflammation control
Non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen can be used for pain and swelling management
Paracetamol can be used as an adjunct
Dosing should be age and weight-appropriate.
Surgical Management:
Indications for surgery include displaced fractures (typically > 2-3 mm displacement), inability to achieve closed reduction, incarcerated menisci, or associated significant ligamentous injuries
Surgical options include: Arthroscopic reduction and fixation: This is the preferred method, offering direct visualization of the fracture, reduction of the fragment, and secure fixation with screws, K-wires, or suture anchors
Open reduction and internal fixation: May be necessary for severely comminuted fractures or complex cases
Open reduction is performed through an anterior arthrotomy.
Supportive Care:
Postoperative care involves adequate pain management, wound care, and adherence to weight-bearing restrictions as prescribed by the surgeon
Physical therapy is essential for regaining range of motion, strength, and proprioception
Crutch use and gait training are important
Close monitoring for signs of infection or complications.
Complications
Early Complications:
Neurovascular injury: Rare, but possible with severe trauma or prolonged compression
Compartment syndrome: Can occur due to swelling and hemorrhage
Infection: Risk associated with open reduction or pin sites
Stiffness and loss of range of motion: Due to pain, swelling, or inadequate rehabilitation
Arthrofibrosis.
Late Complications:
Chronic knee instability: May result from inadequate healing or ligamentous laxity
Post-traumatic arthritis: Due to articular surface damage or malreduction
Persistent pain
Meniscal entrapment: If the fragment is not adequately reduced
Quadriceps contracture
Guarding and gait abnormalities.
Prevention Strategies:
Appropriate pre-participation conditioning and sports-specific training to improve biomechanics and reduce risk
Use of protective equipment during sports
Prompt and accurate diagnosis and management of acute knee injuries
Strict adherence to rehabilitation protocols following surgery or immobilization.
Prognosis
Factors Affecting Prognosis:
Degree of displacement of the fracture fragment
Presence and severity of associated injuries (meniscal tears, ligamentous damage)
Quality of reduction and fixation
Adherence to rehabilitation protocol
Age of the patient at the time of injury
Open vs
closed fractures.
Outcomes:
With appropriate treatment, most children with tibial spine fractures achieve good functional outcomes and return to their pre-injury activity levels
Non-displaced fractures treated non-operatively generally have excellent prognoses
Displaced fractures treated surgically also have a high success rate
However, poor management can lead to long-term disability.
Follow Up:
Regular follow-up appointments with the orthopedic surgeon are necessary to monitor healing, radiographic union, and restoration of knee function
Serial radiographs are obtained to assess healing
Physical therapy evaluation and progression are crucial
Long-term follow-up may be needed to monitor for the development of degenerative joint disease.
Key Points
Exam Focus:
Tibial spine fractures are ACL avulsion injuries in children
Mechanism is typically hyperextension or valgus force with internal rotation on a flexed knee
Imaging: X-rays are initial, CT is gold standard for fracture detail
Surgical fixation is indicated for displaced fractures
Associated meniscal tears are common.
Clinical Pearls:
A palpable step-off over the tibial plateau can be a subtle but important sign of a displaced fracture
Always assess neurovascular status carefully post-injury
Inability to fully extend the knee passively can suggest entrapment of the fragment or meniscus
Don't underestimate the potential for significant associated soft tissue injuries in children.
Common Mistakes:
Missing nondisplaced fractures on plain radiographs
Inadequate evaluation for associated meniscal or ligamentous injuries
Delayed surgical intervention for displaced fractures
Insufficient rehabilitation leading to stiffness or instability
Incorrect management of weight-bearing status.