The prevalence of radiographic criteria of femoral acetabular impingement in patients undergoing hip arthroplasty surgery.
ABSTRACT Pistol grip deformity of the proximal femur has been reported as a potential cause of hip pain and early-onset arthritis. The exact incidence of patients with osteoarthritis resulting from femoral acetabular impingement (FAI) is unknown. The purpose of this study was to explore the relationship between radiographic markers of FAI in patients undergoing hip arthroplasty.
We retrospectively reviewed the radiographs of patients undergoing hip arthroplasty by a single surgeon over a 2-year period. The patients were divided by age, those younger than 65 years and (group A) and those 65 years and older (group B). The radiographs were evaluated for morphology consistent with FAI including an α angle >55°, crossover sign, coxa profunda, acetabular protrusio, and ischial spine sign. Three independent reviewers evaluated all the radiographs. The incidence of CAM, Pincer, and mixed deformities were compared between the 2 groups.
A total of 255 patients with 258 hip arthroplasties were included in this analysis. Group A was found to have a greater number of patients with CAM morphology. Linear regression analysis revealed that the α angle was greater in younger patients.
Patients undergoing hip arthroplasty exhibit a high incidence of radiographic abnormalities consistent with FAI. The CAM-type morphology occurs more frequently in younger patients with advanced arthritis requiring hip arthroplasty. This morphology is thought to cause a delaminating injury to the cartilage of the acetabulum. This study supports the notion that CAM-type morphology is a risk factor for early development of degenerative arthritis of the hip.
SourceAvailable from: Jürg Hodler[Show abstract] [Hide abstract]
ABSTRACT: Impingement by prominence at the femoral head-neck junction on the anterior acetabular rim may cause early osteoarthritis. Our aim was to develop a simple method to describe concavity at this junction, and then to test it by its ability to distinguish quantitatively a group of patients with clinical evidence of impingement from asymptomatic individuals who had normal hips on examination. MR scans of 39 patients with groin pain, decreased internal rotation and a positive impingement test were compared with those of 35 asymptomatic control subjects. The waist of the femoral head-neck junction was identified on tilted axial MR scans passing through the centre of the head. The anterior margin of the waist of the femoral neck was defined and measured by an angle (alpha). In addition, the width of the femoral head-neck junction was measured at two sites. Repeated measurements showed good reproducibility among four observers. The angle alpha averaged 74.0 degrees for the patients and 42.0 degrees for the control group (p < 0.001). Significant differences were also found between the patient and control groups for the scaled width of the femoral neck at both sites. Using standardised MRI, the symptomatic hips of patients who have impingement have significantly less concavity at the femoral head-neck junction than do normal hips. This test may be of value in patients with loss of internal rotation for which a cause is not found.The Bone & Joint Journal 05/2002; 84(4):556-60. · 2.80 Impact Factor
British Journal of Radiology 12/1965; 38(455):810-24. DOI:10.1259/0007-1285-38-455-810 · 1.53 Impact Factor
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ABSTRACT: A multitude of factors including biochemical, genetic, and acquired abnormalities may contribute to osteoarthritis of the hip. Although the pathomechanism of degenerative process affecting the dysplastic hip is well understood, the exact pathogenesis for idiopathic osteoarthritis has not been established. Based on clinical experience, with more than 600 surgical dislocations of the hip, allowing in situ inspection of the damage pattern and the dynamic proof of its origin, we propose femoroacetabular impingement as a mechanism for the development of early osteoarthritis for most nondysplastic hips. The concept focuses more on motion than on axial loading of the hip. Distinct clinical, radiographic, and intraoperative parameters can be used to confirm the diagnosis of this entity with timely delivery of treatment. Surgical treatment of femoroacetabular impingement focuses on improving the clearance for hip motion and alleviation of femoral abutment against the acetabular rim. It is proposed that early surgical intervention for treatment of femoroacetabular impingement, besides providing relief of symptoms, may decelerate the progression of the degenerative process for this group of young patients.Clinical Orthopaedics and Related Research 01/2004; DOI:10.1097/01.blo.0000096804.78689.c2 · 2.88 Impact Factor