The Unexpected Consequence of Breaking Femurs

When I was 3 years old I broke my femur after falling off of my bike. What ensued was surgery to insert a plate and screws followed by placement of a partial body cast, called a Spica cast.  Broken bones are the most common occurrence a child visits the ER, consisting of 14.7% of total ER visits for children (Hoytema van Konijnenburg, Vrolijk-Bosschaart, Bakx, & Van Rijn, 2016). Interestingly, femur fractures are most common in 3-month old’s and between the age of 2 and 3 years old (Brown & Fisher, 2004). The image below shows the incidence rate of femur fractures by ages in months (Brown & Fisher, 2004). After the age of 3, there is a decrease in incidence rate. It is thought that this increase around 3 months of age is due to abuse (Brown & Fisher, 2004). I found it very interesting that on average children begin walking between 14-15 months of age, but the incidence of femur breaks is relatively low (Brown & Fisher, 2004). It is not until they turn two that they are the most prone to femur fractures. One potential theory is that they begin having changes in mobility through climbing and their walking pattern can change which could lead to accidents that result in femur fractures (Brown & Fisher, 2004).

Another interesting aspect of femur fractures is that children can have a difference in limb length in their affected lower limb (Thompson et al., 1997). 19% of all femur fractures in children that are treated with a Spica cast have an unacceptable outcome, which means they have a decreased limb length difference of greater than 2.5cm (Thompson et al., 1997). The other 81% of femur fractures in children that are treated with a Spica cast have an acceptable outcome, which means they have a difference in limb length of a decrease less than 2.5cm (Thompson et al., 1997). The average change in length for all broken femur patients treated with a Spica cast is a range between a decrease in length of 1.7cm to an increases in length up to 0.9cm (Irani, Nicholson, & Chung, 1976). Significance data in Spica cast treatment and limb length has been observed (Thompson et al., 1997).

** This image is from Brown & Fisher, 2004

Brown, D., & Fisher, E. (2004). Femur Fractures in Infants and Young Children. American Journal of Public Health, 94(4), 558–560.

Hoytema van Konijnenburg, E. M., Vrolijk-Bosschaart, T. F., Bakx, R., & Van Rijn, R. R. (2016). Paediatric femur fractures at the emergency department: Accidental or not? The British Journal of Radiology, 89(1061). https://doi.org/10.1259/bjr.20150822

Irani, R. N., Nicholson, J. T., & Chung, S. M. (1976). Long-term results in the treatment of femoral-shaft fractures in young children by immediate spica immobilization. The Journal of Bone and Joint Surgery. American Volume, 58(7), 945–951.

Thompson, J. D., Buehler, K. C., Sponseller, P. D., Gray, D. W., Black, B. E., Buckley, S. L., & Griffin, P. P. (1997). Shortening in femoral shaft fractures in children treated with spica cast. Clinical Orthopaedics and Related Research, (338), 74–78. https://doi.org/10.1097/00003086-199705000-00010