Incidence of Radiographic Cam-Type Impingement in Young Patients (<50) After Femoral Neck Fracture Treated with Reduction and Internal Fixation

Abstract

Background: Cam-type femoral impingement is caused by structural abnormalities of the hip and is recognized as a cause of degenerative hip arthritis. Identifiable etiologies of this structural abnormality include congenital malformation, pediatric hip disease, and malunion of femoral neck fractures after internal fixation. Purpose: The purpose of this study was to determine the prevalence of radiographic impingement in healed Orthopaedic Trauma Association (OTA) type 31B fractures treated with reduction and internal fixation. Methods: Seventy OTA 31B hip fractures treated with internal fixation were identified from our institutional trauma database and radiographs were retrospectively reviewed for signs of impingement. Mean follow-up was 53 months after fracture. Alpha angle, Mose templates, and femoral head retroversion were the measurements used to determine impingement. Results: The overall prevalence of any sign of radiographic impingement was 75%. Alpha angle was elevated in 32 hips (46%), asphericity was present in 46 femoral heads (65%), and femoral head retroversion was present in 26 hips (37%). The rates were highest in displaced subcapital fractures (OTA 31B-3) with a 63%

Endosteal Biologic Augmentation for Surgical Fixation of Displaced Femoral Neck Fractures

“…34 A recent study reported that malunion of FNF resulted in a 75% prevalence of radiographic Cam-type impingement. 25 In our study, patients essentially maintained the initial intraoperative reduction, femoral neck length and offset, and abductor lever arm, corresponding to excellent functional and radiographic outcomes.…”

“…These constructs invariably lead to malunion and femoral neck shortening, negatively affecting hip biomechanics, outcomes, and quality of life. [21][22][23][24][25] The ideal construct provides angle-and length-stability, withstands the forces crossing the fractured femoral neck, and allows controlled microdynamization. We employed an endosteal fibular allograft, serving as a biologic dowel, to reconstruct and augment the comminuted femoral neck and provide structural support to the fully threaded screws construct.…”

Origin of Cam Morphology in Femoroacetabular Impingement

“…Defining cam lesion as the presence of at least 2 of the following criteria—(1) alpha angle greater than 50°, (2) beta angle less than 29°, and (3) head-neck offset ratio less than 0.13—the investigators found cam deformity in 84% of cases. Wendt et al 76 determined prevalence of cam deformity after fracture fixation of subcapital or transcervical femoral neck fractures using a retrospective analysis of 70 fractures in individuals younger than 50 followed for a mean of 53 months after injury. The study found overall prevalence of radiographic signs of impingement to be 75%.…”

A Simple Percutaneous Technique to Reduce Valgus-Impacted Femoral Neck Fractures

“…9) The overall prevalence of radiographic FAI was 75% in patients with a healed FNF that was treated with reduction and internal fixation. 10) Although it is difficult to derive strong conclusions regarding the correlation between FAI and chronic pain, anatomical fracture reduction should be performed to improve the patient outcome. 9,10) There are some limitations to our technique.…”

“…10) Although it is difficult to derive strong conclusions regarding the correlation between FAI and chronic pain, anatomical fracture reduction should be performed to improve the patient outcome. 9,10) There are some limitations to our technique. First, a high posterior tilt angle in an FNF is an independent risk factor of nonunion, but it is difficult to reduce the posterior tilt with our technique.…”