Previous Proximal Femoral Fracture

Introduction

As the life expectancy of the aging “baby boomer” population continues to increase so does the incidence of total hip arthroplasty (THA). In fact, as the demand for improved quality of life has been met with better clinical outcomes, total joint arthroplasty has become one of the most common elective surgical procedures in North America. Improvements in surgical technique along with technical advances in implant design and function have expanded the scope of patients’ eligibility for THA. The femur may be considered deformed once the surgeon deviates from traditional practice and is required to employ nonstandard surgical techniques and implants. Atypical anatomy contributes to the surgical complexity encountered by the surgeon as femoral osteotomies and the use of nontraditional components may be needed. As a result, THA in femoral deformity patients is associated with a higher incidence of complications, such as intraoperative fractures, aseptic femoral loosening, instability, infection, and osteotomy nonunion. Furthermore, femoral deformity poses technical challenges to the surgeon, including difficulties with exposure, proper implant positioning, and fixation. Ultimately, in order to prolong implant survival rates in patients with proximal femoral deformity, proper perioperative planning is warranted to restore the hip's center of rotation, restore leg length and offset, maximize fixation, and limit component impingement and instability. Preoperative planning helps the surgeon prepare the appropriate implants to best handle the femoral deformity.

The goals of femoral reconstruction include restoring native biomechanics of the hip and achieving femoral integrity. In an attempt to improve preoperative planning, femoral deformity classification systems have been developed. D'Antonio and coworkers divided abnormalities of the femur into segmental and cavitary. The former involved loss of bone in the cortical shell of the femur and the latter involved loss of cancellous or endosteal cortical bone without disruption of the outer cortical shell. To further specify the abnormality, they assigned levels of bony involvement. Level I was localized to bone proximal to the inferior aspect of the lesser trochanter, level II was localized from the inferior lesser trochanter to 10 cm distal from the lesser trochanter edge, and level III was localized to bone distal to level II. Later, Berry published a widely regarded classification method that focused primarily on the anatomic site of deformity with further subclassifications focusing on geometry and etiology of deformity. The anatomic site impacts the technical surgical challenges encountered while the etiology and geometry of the deformity ultimately guide the surgeon's choice in implant selection, position, and need for osteotomy. Moreover, the etiology of femoral deformity can be classified as a result of a congenital anomaly or a traumatic injury. Congenital anomalies contributing to femoral deformity include developmental dysplasia of the hip (DDH), coxa vara, and excess anteversion. Traumatic causes include previous femoral fracture (treated or not treated by internal fixation), previous femoral head resection, and avascular necrosis (AVN) secondary to sickle cell disease. Deformities due to diagnoses such as DDH tend to follow predictable variations in anatomy while those due to failed fracture fixations do not, underscoring the importance of primarily identifying the etiology of the deformity when preoperatively planning for THA.

When considering THA in the setting of proximal femoral deformity, certain anatomic and mechanical characteristics of the deformity must be addressed, including control of anteversion, restoration of the hip's offset, stabilization of the implant, and restoration of leg length. Femoral stem anteversion or retroversion, and structural abnormalities often associated with dysplasia or trauma, have a direct impact on joint stability postoperatively, as excessive anteversion can result in postoperative anterior instability, while retroversion can lead to impingement and posterior instability. Restoration of native femoral offset—and, thus, the abductor lever arm of the hip—optimizes abductor muscle force and has been associated with a decreased rate of dislocation, further underscoring the importance of the restoration of proper hip biomechanics for favorable THA outcomes. Control of appropriate lower limb length can decrease the risk for lower back pain, dislocation, and limp.

Contraindications for Total Hip Arthroplasty

As more attention is being directed toward clinical outcomes and health care spending, and as the demand for THA increases, a greater emphasis has been placed on appropriate patient selection and preoperative optimization. Improvements in quality of life, including relief of pain, decreased limitations in functional ability, gain of independence with activities of daily living, and higher energy levels are among the main reasons patients elect to undergo THA. However, THA needs to be reconsidered when the risks of surgery outweigh the benefits, specifically in the setting of active systemic or local infection and severe uncontrolled medical or psychiatric illness that renders the patient unstable. Therefore, all modifiable risk factors should be addressed and the patient should be optimized prior to elective THA. Other conditions that need to be taken into account when a THA is being considered are neuropathic arthropathy and rapidly progressing neurologic disease. There are occasions when the femoral canal is extremely compromised, sclerotic, or deformed but the femoral head and neck are relatively intact in the presence of severe degeneration of the joint. As an alternative, these cases may be candidates for hip resurfacing rather than THA ( Fig. 78.1 ).