Study Guide
Patellar Fractures
Key Points:
- Osseous patellar fractures are generally caused by direct blows, and are treated similar to adult patella fractures
- Patellar sleeve fractures are generally caused by indirect mechanisms, and one needs a high level of suspicion to diagnose these injuries
- Although only a small bony fragment is seen in patellar sleeve fractures, a significant cartilaginous component exists and operative fixation is generally recommended
Description:
The patella is the largest sesamoid in the body. Ossification typically begins by age 6 and continues into the second decade. Patella fractures are relatively rare. Osseous fractures caused by a direct blow typically result in adult type vertical or transverse fractures. Indirect fractures occur as a result of a forceful quadriceps contraction, and in skeletally immature patients, generally lead to patella sleeve fractures in which a small osseous fragment and sleeve of periosteum/perichondrium and cartilage is disrupted from the osseous patella.(Houghton 1979)Epidemiology:
Patella sleeve fractures are most common in children aged 8-16 years, and are more likely to occur during adolescence. More than half of patella fractures in skeletally immature patients are patella sleeve fractures. (Hunt 2005)Clinical Findings:
Osseous fractures present with a knee effusion, point tenderness at the fracture site, and the inability to extend the knee fully without pain. Patella alta is frequently present as well.Imaging Studies:
AP/lateral radiographs demonstrate the fracture configuration. CT and MRI are generally not required, but may be useful in planning surgery for comminuted fractures or to detect osteochondral fragments.Treatment:
Treatment principles are similar to management of these fractures in adults. Fractures that are displaced require open (operative) management to restore function of the extensor mechanism.![](/POSNA/media/Images/Study%20Guide%20Images/Patella%20Fractures/Patella1.jpg)
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14 yo fell onto knee one month prior to these Xrays
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![](/POSNA/media/Images/Study%20Guide%20Images/Patella%20Fractures/Patella4.jpg)
![](/POSNA/media/Images/Study%20Guide%20Images/Patella%20Fractures/Patella5.jpg)
6 months after open reduction and internal fixation
Related Videos:
References:
- Gettys FK, Morgan RJ, Fleischli JE. Superior Pole Sleeve Fracture of the Patella. Am J Sports Med 38(11):2331-2336, 2010.
- Grogen DP, Carey TP, Leffers D, Ogden JA. Avulsion Fractures of the Patella. J Pediatr Orthoped 10: 721-730, 1990.
- Houghton GR, Ackroyd CE. Sleeve fractures of the patella in children. J Bone Joint Surg Br 61:165-168, 1979.
- Hunt DM, Somashekar N. A review of sleeve fractures of the patella in children. The Knee 12:3-7, 2005.
- Maripuri SN, Mehta H, Mohanty K. Sleeve fracture of the superior pole of the patella with an intra-articular dislocation: a case report. J Bone Joint Surg Am 90(2):385-389, 2008.