4 Fractures of the Femur

Overview

Anatomic Features

The femur is the longest and largest tubular bone in the human skeleton; the average length of an adult femur is 42.48 cm on the left side and 42.39 cm on the right side. The femur is cylindric in the upper third of its length, with the pectineal line running through the posterome-dial surface of the femur, up to the base of the lesser trochanter. The pectineal line then continues with the intertrochanteric line, and down to the medial lip of the linea aspera. The gluteal tuberosity lies on the posterolateral aspect of the femur, up to the base of the greater trochanter and down to the lateral lip of the linea aspera. The middle part of the femur is slightly twisted and curved, with an anterior convexity that is 30° rotated from the superolateral to inferomedial part of the femur. The lower third of the femur becomes flattened and widened anteroposteriorly. The linea aspera on the dorsal side of middle third has two lips that diverge and turn into the medial and lateral supracondylar ridge, respectively. The rough impression above the medial epicondyle gives origin to the medial head of the gastrocnemius, while the plantaris arises in the impression above and to the medial side of the lateral epicondyle (Plate 4.1).

Based on the AO classification, femur fracture is coded as number “3.” According to “Heim’s square,” the anatomic delineation of the proximal and distal shaft is number “31, 32, and 33,” respectively (Plates 4.2 and 4.3).

Clinical Epidemiologic Features of Femur Fractures

A total of 7660 patients with 7756 femoral fractures were treated at our trauma center over a 5-year period from 2003 to 2007. All cases were reviewed and statistically studied; the fractures accounted for 12.71% of all patients with fractures and 11.88% of all types of fractures, respectively. Among these 7660 patients, 697 were children with 701 fractures, and 6963 were adults with 7055 fractures.

Epidemiologic features of femur fractures are as follows:

• more males than females

• more left-side than right-side injuries

• the highest-risk age group is 31–40 years. The most affected male age group is 31–40 years, while females aged 71–80 years have the highest risk

• the proximal femur fracture is the most common femur fracture.

The head of the femur is globular in shape and forms about two-thirds of a sphere (Plate 4.4). The neck projects forward to some extent, with an average anterior projection of 10–15°. Flattened posteriorly, the neck is contracted in the middle, which is often the site of fractures. In adults, the neck forms an angle of ~ 120–130° with the body. At the junction of the neck with the upper part of the body, there is a large eminence called the greater trochanter. A smaller eminence projecting from the lower and posterior part of the base of the neck is called the lesser trochanter. Running obliquely downward and medial from the tubercle is the intertrochanteric line, while the intertrochant-eric crest courses obliquely downward and medially from the summit of the greater trochanter on the posterior surface of the neck.

AO Classification of Proximal Femur Fractures

Based on AO classification, the proximal femur is coded as the number “31.” It is further divided into three types: 31-A: trochanteric fracture (extra-articular); 31-B: femur neck fracture (articular); 31-C: femur head fracture (intra-articular) (Plate 4.5).

Related posts:

Spinal Fractures Fractures of the Pelvic Ring and Acetabulum Hand Fractures Fractures of the Humerus Fractures of the Tibia/Fibula Foot Fractures

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