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PEARLS & PITFALLS – SURGICAL TECHNIQUE
Arthroscopic All-Epiphyseal Suture-Anchor Fixation of Tibial Eminence Fractures
Tigran Garabekyan, MD
Huntington, WV, USA
Background and Classification
Tibial eminence fractures are typically seen in children and young adolescents who sustain a low-energy, non- contact knee injury. The deforming force characteristically causes attenuation of the anterior cruciate ligament (ACL) prior to disrupting the incompletely ossified tibial eminence. If suspected, an MRI should be obtained to rule out concomitant injuries to the menisci, articular cartilage, and collateral ligaments.
Surgical Technique
Candidates for operative management are treated within 2 – 3 weeks of the injury to facilitate anatomic reduction. Early surgery also reduces the period of pre-operative immobilization as patients typically guard against motion due to pain and presence of lipohemarthrosis. The surgeon is prepared to address all concomitant injuries including articular cartilage lesions and meniscal tears, with efforts directed to preserve and repair native structures.
The operating room is equipped with 0.062”C-wires, a wire driver, standard knee arthroscopy instruments, and various suture anchors. Given the small size of the typical patient, a regular OR table, with the patient positioned centrally, is adequate for fluoroscopic visualization should it be desired. In the majority of cases, a fluoroscope is not utilized as direct visualization allows for excellent assessment. A bump is placed under the ipsilateral hip.
Standard diagnostic arthroscopy is performed utilizing anteromedial (AM) and anterolateral (AL) working portals, and a superomedial outflow portal. An accessory medial (AccM) portal is made to facilitate suture passage. The fracture fragment is assessed for size and extension into the medial and lateral compartments. With the knee at 90 degrees of flexion, the fracture bed is lightly debrided utilizing an oscillating shaver, removing interposed hematoma and fibrous tissue that would otherwise impede anatomic reduction. Care is taken to avoid aggressive debridement to preserve bone stock and native growth factors present in the fracture hematoma (Fig. 2).
The next step involves reduction and provisional stabilization of the fragment to facilitate suture passage. While viewing with a 70-degree arthroscope through the AL portal, a 0.062” C-wire is inserted percutaneously at the medial border of the patella and advanced freehand to gently manipulate and depress the fragment into anatomic alignment. A probe is inserted through the AM portal and used to retract the intermeniscal ligament anteriorly while the fragment is manipulated with the C-wire. Following reduction, the intermeniscal ligament is released and rests on top of the fragment, stabilizing it from re-displacing. As the C-wire is advanced across the medial aspect of the fracture, the medial joint reduction is visualized and confirmed to be anatomic (Fig. 3).
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The most commonly used classification system is that proposed by Meyers and McKeever who originally grouped the injuries into three types. Type I fractures are non- displaced and typically treated non-operatively in a cylinder cast. Type II fractures have anterior cortical displacement with an intact posterior hinge. If near anatomic reduction can be achieved with gentle knee extension, a Type II fracture may be treated non-operatively. Otherwise, with inadequate reduction (often due to interposed structures) or in the presence of concomitant injuries, operative treatment should be sought. Type III fractures are completely displaced and typically treated surgically (Fig. 1).
Zaricznyj later added a Type IV category to describe comminuted fractures, which was more relevant at the time due to implications for screw fixation.
18 ISAKOS NEWSLETTER 2015: Volume I