Screw Fixation of Pediatric Tibial Tubercle Fractures
Authors: Rickert Kathleen D. , Hedequist Daniel , Bomar James D. 
Published: June 2021

Background:
Tibial tubercle fractures are rare injuries that account for <1% of physeal fractures. These fractures are thought to be increasing in frequency, particularly in young, adolescent males who participate in basketball and other sports with repeated running and jumping. The tibial apophysis becomes mechanically vulnerable as the proximal tibial physis closes from posteromedial to anterolateral, enabling the quadriceps to overpower the chondroepiphysis and avulse the proximal tibial epiphysis from the tibial metaphysis.

Description:
Position the patient supine with the leg on a bump or bone foam. Perform a longitudinal incision centered over the fracture site (i.e., the tibial tubercle); a medial parapatellar incision may be utilized if an intra-articular component is present. Develop medial and lateral soft-tissue flaps to expose the fracture. Evaluate the soft-tissue stripping and capsule. Debride any hematoma, fracture fragments, and soft tissue from the fracture site with use of irrigation and a curet. Use a towel clip, bone clamp, and/or ballpoint pusher to reduce the fragment. Place 2 to 3 parallel guide pins from anterior to posterior, capturing fracture fragments within the epiphysis and apophysis under fluoroscopic guidance. Carefully place a guidewire in the distal fragment to avoid splitting the fragment, which is often small. An arthrotomy or arthroscopy is utilized to assess intra-articular reduction if necessary. Assess and measure pin lengths and placement with use of fluoroscopy. Place screws sequentially to avoid rotation of the fragment and take care to avoid splitting the fragment when placing distal screws. Repair any patellar, capsular, retinacular, or meniscal damage. A suture anchor may be utilized to repair the patellar tendon if necessary. The skin is closed in a layered fashion. Apply a cylinder cast or hinged knee braced locked in extension.

Alternatives:
Nonoperative treatment in a long-leg cast in extension may be considered for nondisplaced fractures or fractures that are stably reduced with <2 mm of displacement and acceptable alignment in the cast following reduction. Operative treatment is indicated for fractures with ≥2 mm of displacement, intra-articular extension with an incongruent joint, and for patients who will not tolerate being non-weightbearing in a cast. Closed reduction is generally attempted for fractures without intra-articular extension. If closed reduction is successful, fixation may be performed with Kirschner wires and/or percutaneous screws. Open reduction is often necessary and has been reported to be performed in as many as 98% of surgical cases for tubercle fractures
2
.

Rationale:
This approach allows access to intra-articular displacement and the ability to obtain a stable, anatomic reduction while addressing concomitant soft-tissue injury, if present.

Expected Outcomes:
The expectation following successful reduction and screw fixation of tibial tubercle fractures is that these young patients will be able to regain their motion and strength, and ultimately return to preinjury activity levels. A consecutive series of 86 patients with surgically treated tibial tubercle fractures found that all patients demonstrated full radiographic healing at the time of the latest follow-up (range, 3 to 34 months), return to full activities between 10 and 42 weeks, return of good to excellent range of motion in 89% of patients, and a 10% to 20% complication rate, including partial physeal arrest, decreased range of motion, quadriceps contracture, and painful implants. Additionally, a systematic review of 23 articles with 336 surgically treated tibial tubercle fractures found 98% of patients return to preinjury activity and knee range of motion with a 28% complication rate (most commonly due to painful implants).

Important Tips:

Place the fluoroscopic image view across the room from the surgeon for ease of viewing.Use computed tomography or magnetic resonance imaging if the fracture has intra-articular extension.Use 4.5 or 6.5-mm cannulated, partially threaded screws.Carefully monitor for compartment syndrome.Place screws by hand, sequentially.