Chapter 19: Thigh

Introduction

The thigh is the largest anatomical portion of any extremity, and is comprised of powerful muscle groups that encase the femoral shaft. The femur is the heaviest and longest bone in the body. It has an excellent blood supply derived from the profunda femoris artery, and its periosteum receives extensive collateral circulation. As a result, the femur is well protected from devascularization and has good healing potential.

The musculature of the thigh is divided into three compartments by intermuscular septa that attach to the linea aspera, a ridge that runs down the posterior aspect of the femur (Fig. 19–1). The anterior compartment contains hip flexors and knee extensors, including the four quadriceps muscles (the rectus femoris, vastus medialis, vastus lateralis, and vastus intermedius). The posterior compartment is occupied by the hamstrings, which include the long and short heads of the biceps femoris as well as the semimembranosus and semitendinosus muscles medially. The medial compartment consists of the adductor muscle group, which includes the adductor longus, brevis, and magnus, as well as the gracilis.

Femur Fractures

Femoral Shaft Fractures

The femoral shaft extends from an area 5 cm distal to the lesser trochanter to a point 8 cm proximal to the adductor tubercle.

Femoral shaft fractures are classified into three types.

1. Spiral, transverse, or oblique shaft fractures

2. Comminuted femoral shaft fractures

3. Open femoral shaft fractures

Distinguishing between a spiral, transverse, or oblique fracture does not alter either the treatment or prognosis.

Comminuted fractures are further classified by Winquist based on the size of the fracture fragment and the degree of comminution (Fig. 19–2).¹ Grade I fractures have minimal or no comminution, and fracture fragments are small (≤25% of the width of the femoral shaft). Grade II fractures possess a fracture fragment of 25% to 50%, whereas grade III fractures are associated with a large butterfly fragment (>50% of the width of the femoral shaft). Grade IV fractures possess circumferential comminution over an entire segment of bone with complete loss of abutment of the cortices.

Atypical femur fractures result from brittle bone failure rather than significant trauma. These fractures are characterized by a transverse morphology and lack of comminution.^2,3 Atypical femur fractures occur from an area distal to the lesser trochanter to just proximal to the supracondylar flare of the distal femoral metaphysis. Several recent studies have tried to show an increased risk of atypical femur fractures with the use of bisphosphonates although such a definitive association remains unclear.^2,3 Nevertheless, these ...