Radiographic prevalence of CAM-type femoroacetabular impingement after open reduction and internal fixation of femoral neck fractures.
OBJECTIVE
The purpose of this study was to estimate the radiographic prevalence of CAM-type femoroacetabular impingement (FAI) in elderly patients (≥ 50 years) who have undergone internal fixation for femoral neck fracture.


METHODS
A total of 187 frog-leg lateral radiographs of elderly patients who underwent internal fixation for a femoral neck fracture were reviewed by two independent reviewers. The alpha angle, beta angle, and femoral head-neck offset ratio were calculated. The presence of two abnormal radiographic parameters was deemed to be diagnostic of radiographic CAM-type impingement.


RESULTS
Radiographic CAM-type FAI was identified in 157 out of 187 (84 %) patients who underwent internal fixation for fractures of the femoral neck. Moderate-to-good inter-observer reliability was achieved in the measurement of radiographic parameters. With reference to fracture subtypes and prevalence of radiographic features of CAM-type morphology, 97 (72 %) out of 134 patients were positive for CAM in Garden subtypes I and II, whereas 49 (85.9 %) out of 57 patients had radiographic CAM in Garden III and IV subtypes.


CONCLUSIONS
There was a high prevalence of CAM-type FAI in patients that underwent surgical fixation of femoral neck fractures. This is significantly higher than the reported prevalence in non-fracture patient populations. The high prevalence of CAM morphology could be related to several factors, including age, fracture morphology, quality of reduction, type of fixation, and fracture healing.
Division of Orthopaedic Surgery, Department of Surgery, McMaster University, 1200 Main Street West, 4E15, Hamilton, ON, L8N 3Z5, Canada.
G
G
Mathew
M
M
Kowalczuk
B
B
Hetaimish
A
A
Bedi
M J
MJ
Philippon
M
M
Bhandari
N
N
Simunovic
S
S
Crouch
O R
OR
Ayeni
D000368:Aged; D005260:Female; D057925:Femoracetabular Impingement / Q000000981:diagnostic imaging* / Q000209:etiology; D005265:Femoral Neck Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D005593:Fracture Fixation, Internal / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011859:Radiography; D015203:Reproducibility of Results