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A 16-year-old boy presents to the office with left knee pain and instability after a ski injury that occurred 2 days ago. The patient reports falling while skiing; during the fall the knee buckled awkwardly. He says he was unable to ski down the mountain after the injury and was seen in the emergency department a few hours later, where radiographs showed a tibial spine avulsion fracture (Figures 1 and 2). Magnetic resonance imaging (MRI) was performed the next day and further identified an avulsion fracture of the tibial spine at the distal attachment site of the anterior cruciate ligament (ACL) with 3 mm of displacement (Figure 3).
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The tibial spine is the distal attachment site of the anterior cruciate ligament (ACL). A tibial spine fracture is uncommon but can occur before skeletal maturity. At that stage of development, the ligament may be stronger than the attachment site leading to fracture rather than ligament rupture when pressure is applied.1,2
Fractures that do not displace the bone can be treated nonsurgically with a knee immobilizer set with slight flexion (less tension on ACL) until the fracture heals. If there is any question of fracture displacement, computed tomography (CT) can provide a precise measurement. An MRI helps delineate the fracture and identify other soft tissue injuries.1,2
Minimally displaced fractures may be treated with the knee placed in extension. Displaced and nondisplaced fractures that cannot be reduced require surgical fixation, most commonly with an arthroscopic approach. The most common arthroscopic technique involves using a suture to pull the fracture back down for an anatomic reduction. Postoperative weight-bearing and range of motion are dependent on the surgeon’s preference, although early motion helps reduce the risk of arthrofibrosis. The expected return to sports is 3 to 4 months.1,2
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor in chief of the Journal of Orthopaedics for Physician Assistants.
References
1. Herman MJ, Martinek MA, Absug JM. Complications of tibial eminence and diaphyseal fractures in children: prevention and treatment. J Am Acad Orthop Surg. 2014;22(11):730-741. doi:10.5435/JAAOS-22-11-730
2. Osti L, Buda M, Soldati F, Del Buono A, Osti R, Maffulli N. Arthroscopic treatment of tibial eminence fracture: a systematic review of different fixation methods. Br Med Bull. 2016;118(1):73-90. doi:10.1093/bmb/ldw018
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