Abstract

Avulsion fractures of the tibial eminence have been well-described in children and adults with an increased incidence resulting from road traffic and athletic accidents. Surgical treatment isadvocated because of the high incidence of the nonunion and instability following conservative treatment. We report a case of avulsion fracture of tibial spine in a 15-year-old boy who fellfrom his cycle and presented to the casualty complaining of left knee pain. Since, it was a closed fracture, he was treated using long-leg cast immobilization in a few degrees of knee flexion for 5-6 weeks.

Case Report

A 15-year-old boy fell from his cycle and presented to the casualty complaining of left knee pain.

Examination

Examination revealed a swollen left knee; skin was intact; on palpation, there was diffuse tenderness over the knee; valgus stress at full extension and at 30 degrees revealed an increased laxity on the left; anterior draw and Lachman tests were also asymmetric with an increased excursion on the left and neurovascular examination was unremarkable.

Radiographic findings

Radiographic findings revealed avulsion fracture of the tibial spine. Adequate anteroposterior and lateral X-rays are essential to evaluate the degree of displacement of the anterior tibial spine. Fracture is best seen on the lateral radiograph. A displaced osteochondral fragment from the patella or femoral condyle may simulate a fracture of the tibial spine. If an magnetic resonance imaging (MRI) study is done, a concomitant partial tear of the anterior cruciate ligament (ACL) may be noted in some cases.

Management

Since, it was a closed fracture, he was treated as per management guidelines for type 1fractures. Type 1 fractures can be treated using long leg cast immobilization in a few degrees of knee flexion for 5-6 weeks.

In type 2 fractures, with the child under general anesthesia, the knee is hyperextended to attempt fracture reduction by forcing the elevated anterior portion of the fracture fragment back into place through the contact pressure of the femoral condyles. Afterwards, the knee is brought back to a position of a few degrees of flexion for long-leg cast immobilization. Casting in full extension or hyperextension should be avoided to prevent excessive popliteal artery stretch and a resultant lower-leg compartment syndrome.

If this closed maneuver is unsuccessful, operative reduction is needed.

Discussion

Avulsion fractures of the tibial eminence have been well-described in children and adults with an increased incidence resulting from road traffic and athletic accidents. According to the literature, only surgical treatment is advocated because of the high incidence of the nonunion and instability following conservative treatment. Open reduction can cause some morbidity and, therefore, arthroscopic techniques have been developed. The limitations of the techniques are related to technical difficulty and unstable fixation.

Etiology

Injury is caused by hyperextension of the knee associated with some lateral movement leading to increased stress on the ACL. The most common activity associated with this fracture is bicycle riding.

Classification

Meyer’s and McKeever have described three main types of intercondylar fractures in children-based on the amount of displacement and the fracture pattern seen on the initial radiographs. Type 1 is nondisplaced and does not interfere with knee extension. The type 2 fracture has a posterior hinge with the anterior portion being elevated. In this type, knee extension is generally limited, and there is a possibility that the anterior horn of the meniscus is caught under the anterior fracture fragment. A type 3 fracture is fully displaced, usually with the knee held in a mildly flexed position. Operative reduction is indicated for all type 3 fractures. The goal for operative treatment is to remove the soft tissue (usually the meniscus and blood clot Fig. 3) that is blocking reduction and to secure the reduction. After reduction and fixation, a long-leg cast is applied with the knee in neutral or slight flexion for 6-8 weeks.

Prognosis and complications

With appropriate treatment, follow-up results are very good. Nonunion is rare -although mild, asymptomatic laxity of the ACL is often present after the final healing of the fracture. This is why most advocate countersinking the tibial spine fragment during reduction.

Source: Levy HJ, Fowble VA. Arthroscopy 2001;17(5):E20.