BACKGROUND:

Recent advances in the understanding of the anatomy and function of the acetabular labrum suggest that it is important for normal joint function. We found no available data regarding whether labral refixation after treatment of femoro-acetabular impingement affects the clinical and radiographic results.

METHODS:

We retrospectively reviewed the clinical and radiographic results of fifty-two patients (sixty hips) with femoro-acetabular impingement who underwent arthrotomy and surgical dislocation of the hip to allow trimming of the acetabular rim and femoral osteochondroplasty. In the first twenty-five hips, the torn labrum was resected (Group 1); in the next thirty-five hips, the intact portion of the labrum was reattached to the acetabular rim (Group 2). At one and two years postoperatively, the Merle d'Aubigne clinical score and the Tonnis arthrosis classification system were used to compare the two groups.

RESULTS:

At one year postoperatively, both groups showed a significant improvement in their clinical scores (mainly pain reduction) compared with their preoperative values (p = 0.0003 for Group 1 and p < 0.0001 for Group 2). At two years postoperatively, 28% of the hips in Group 1 (labral resection) had an excellent result, 48% had a good result, 20% had a moderate result, and 4% had a poor result. In contrast, in Group 2 (labral reattachment), 80% of the hips had an excellent result, 14% had a good result, and 6% had a moderate result. Comparison of the clinical scores between the two groups revealed significantly better outcomes for Group 2 at one year (p = 0.0001) and at two years (p = 0.01). Radiographic signs of osteoarthritis were significantly more prevalent in Group 1 than in Group 2 at one year (p = 0.02) and at two years (p = 0.009).

CONCLUSIONS:

Patients treated with labral refixation recovered earlier and had superior clinical and radiographic results when compared with patients who had undergone resection of a torn labrum. Although the results must be considered preliminary, we now recommend refixation of the intact portion of the labrum after trimming of the acetabular rim during surgical treatment of femoro-acetabular impingement.

Treatment of Femoro-Acetabular Impingement: Preliminary Results of Labral Refixation

Purpose: To retrospectively characterize magnetic resonance (MR) arthrographic findings in patients with cam femoroacetabular impingement (FAI) and in those with pincer FAI. Materials and Methods: Institutional review board approval and informed consent were not required. MR arthrographic studies obtained in 50 consecutive patients (30 men, 20 women; mean age, 28.8 years) with FAI were analyzed for labral abnormalities, cartilage lesions, and osseous abnormalities of the acetabular rim. The nonspherical shape of the femoral head at the head-neck junction was measured in eight positions around the femoral head and neck and used to calculate the α angle. Acetabular depth was measured. Surgical diagnosis served as the reference standard. The Wilcoxon rank sum test was used for statistical analysis. Results: At surgery, hips in 33 patients were classified as having cam FAI and hips in 17 patients were classified as having pincer FAI. In both groups, the mean age of patients was 28.8 years. There were signific...

Cam and Pincer Femoroacetabular Impingement: Characteristic MR Arthrographic Findings in 50 Patients

Background: Femoroacetabular impingement is a cause of hip pain in adults and is a possible precursor of osteoarthritis, with the cam type of impingement being the most common. The purpose of this study was to determine the prevalence of cam-type morphology of the hip in asymptomatic patients.

Methods: Two hundred asymptomatic volunteers with no prior hip surgery or childhood hip problems underwent magnetic resonance imaging targeted to both hips. The subjects were examined at the time of magnetic resonance imaging for internal rotation of the hips at 90° of hip flexion and for a positive impingement sign. The contour of the femoral head-neck junction was quantified with use of the alpha angle. A value of >50.5° was considered positive for cam morphology. Measurements were performed independently by two musculoskeletal radiologists.

Results: The mean age of the individuals was 29.4 years (range, 21.4 to 50.6 years); 79% were white, and 55.5% were women. The mean alpha angle anteriorly at the three o’clock position was 40.9° ± 7.0° on the right and 40.6° ± 7.1° on the left, whereas the mean alpha angle anterosuperiorly at the 1:30 position was 50.2° ± 8.0° on the right and 50.1° ± 8.3° on the left. Fourteen percent of the volunteers had at least one hip with cam morphology: 10.5% had an elevated alpha angle on either the right or the left side, and 3.5% had the deformity in both hips. Seventy-nine percent (twenty-two) of twenty-eight individuals who had an elevated alpha angle were men, and 21% (six) were women. Individuals with an elevated alpha angle on at least one side tended to be male (p < 0.001), with 24.7% (twenty-two) of eighty-nine men having cam morphology compared with only 5.4% (six) of 111 women.

Conclusions: The prevalence of cam-type femoroacetabular impingement deformity is higher in men as well as in individuals with decreased internal rotation. Defining what represents a normal head-neck contour is important for establishing treatment strategies in patients presenting with prearthritic hip pain.

Prevalence of Cam-Type Femoroacetabular Impingement Morphology in Asymptomatic Volunteers

Femoroacetabular impingement (FAI) is a recently proposed mechanism causing abnormal contact stresses and potential joint damage around the hip. In the majority of cases, a bony deformity or spatial malorientation of the femoral head or head/neck junction, acetabulum, or both cause FAI. Supraphysiologic motion or high impact might cause FAI even with very mild bony alterations. FAI became of interest to the medical field when (1) evidence began to emerge suggesting that FAI may initiate osteoarthritis of the hip and when (2) adolescents and active adults with groin pain and imaging evidence of FAI were successfully treated addressing the causes of FAI. With an increased recognition and acceptance of FAI as a damage mechanism of the hip, defined standards of assessment and treatment need to be developed and established to provide high accuracy and precision in diagnosis. Early recognition of FAI followed by subsequent behavioral modification (profession, sports, etc) or even surgery may reduce the rate of OA due to FAI.

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The concept of Femoroacetabular impingement: Current status and future perspectives

Purpose: The aim of this study was to determine the prevalence of radiographic findings suggestive of femoroacetabular impingement (FAI) in asymptomatic individuals. Methods: A systematic review was performed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies reporting radiographic, computed tomographic, or magnetic resonance imaging (MRI) findings that were suggestive of FAI in asymptomatic volunteers were included. Cam, pincer, and combined pathologic conditions were investigated. Results: We identified 26 studies for inclusion, comprising 2,114 asymptomatic hips (57.2% men; 42.8% women). The mean participant age was 25.3 � 1.5 years. The mean alpha angle in asymptomatic hips was 54.1 � � 5.1 � . The prevalence of an asymptomatic cam deformity was 37% (range, 7% to 100% between studies)d54.8% in athletes versus 23.1% in the general population. Of the 17 studies that measured alpha angles, 9 used MRI and 9 used radiography (1 study used both). The mean lateral and anterior center edge angles (CEAs) were 31.2 � and 30 � , respectively. The prevalence of asymptomatic hips with pincer deformity was 67% (range 61% to 76% between studies). Pincer deformity was poorly defined (4 studies [15%]; focal anterior overcoverage, acetabular retroversion, abnormal CEA or acetabular index, coxa profunda, acetabular protrusio, ischial spine sign, crossover sign, and posterior wall sign). Only 7 studies reported on labral injury, which was found on MRI without intra-articular contrast in 68.1% of hips. Conclusions: FAI morphologic features and labral injuries are common in asymptomatic patients. Clinical decision making should carefully analyze the association of patient history and physical examination with radiographic imaging. Level of Evidence: Level IV, systematic review if Level II-IV studies.

Prevalence of Femoroacetabular Impingement Imaging Findings in Asymptomatic Volunteers: A Systematic Review

Introduction and Aims: There is a relationship between the anatomy of the hip joint and the development of arthritis. A common cause of hip pain in the young adult that can lead to arthritis is acetabular dysplasia. More recently, femoroacetabular impingement has been described as another cause of hip pain. The purpose of our study was to evaluate the applicability of pelvic computed tomography (CT) with three-dimensional surface rendering to evaluate femoro-acetabular impingement. Method Thirty-six hips (30 patients; 17 males; 13 females) with persistent hip pain, mean age 41 (37–52), underwent three-dimensional CT of the pelvis, as well as MRI arthrography with gadolinium enhancement. On 3D CT, the concavity of the femoral head-neck junction (offset), alpha angle as described by Notzli was calculated to depict the anterior femoral neck contour. The concavity of the posterior aspect of the head neck junction was measured as the beta angle. The same measurements were made in 20 hips, consisting of randomly selected patients with no prior history of hip pathology or pain (mean age 37; 13 males; eight females). Results The mean alpha angle for the symptomatic group was 66.4 (39–94) and 43.8 (39.3–48.3) for the control group (p=0.001). All symptomatic hips had abnormal findings on MRA: labral tears in all; cartilage delamination/ulceration in 14 hips; herniation pits in six hips. The majority of labral tears and delamination were located in the antero-superior quadrant. In the surgical treated group, all MRA findings were confirmed. The mean beta angle was significantly smaller (increase concavity) in the symptomatic versus the controls: 40.2 versus 43.8 (p=0.011). Interestingly in the symptomatic group the beta angle was significantly lower than the alpha angle (p Conclusion: 3D CT with surface rendering and multiplanar reformation is useful to determine degree of bone buttressing of the anterior femoral head-neck junction quantitatively assessed by alpha angle measurement, which is elevated in patients with femoro-acetabular impingement. With a greater posterior concavity i.e. small beta angle in the symptomatic group versus the control, subclinical slipped femoral epiphysis remains a plausible cause of this deformity.

Three-dimensional computed tomography of the hip in the assessment of femoroacetabular impingement

http://www.medecine.uottawa.ca/Radiology/assets/documents/msk_imaging/articles/3%20Dimensional%20CT%20of%20the%20Hip%20in%20the%20Assessment%20of%20Femeroacetabular%20Impingement.pdf

Three‐dimensional computed tomography of the hip in the assessment of femoroacetabular impingement

The outcome of joint-preserving procedures for the treatment of hip osteonecrosis1,2 and acetabular dysplasia3 has been related to the quality of the acetabular cartilage at the time of the operative intervention4-7. An ability to evaluate the condition of the acetabular cartilage prior to surgical intervention could improve the predictability of the results of joint-preserving procedures. To accomplish this goal, some have advocated the use of hip arthroscopy8-10. However, this method relies on visual inspection of the articular surface and probing it to find abnormalities in texture or hidden defects within the midsubstance of the tissue. Less-invasive diagnostic measures, such as magnetic resonance imaging, would be preferable11.

We describe a series of four consecutive patients who demonstrated delamination of the hip joint acetabular cartilage on magnetic resonance arthrography with gadolinium, which was then confirmed at the time of surgical dislocation of the hip joint12. The characteristics of these lesions as well as the imaging technique are described. Informed consent was obtained from each patient prior to submission of this paper for publication.

All four patients presented with persistent hip pain radiating to the groin area that was reproduced with flexion, adduction, and internal rotation (the so-called impingement test). The mean age of the patients was forty years (range, thirty-six to forty-five years) at the time of presentation. There were three men and one woman, and they had a mean duration of symptoms of 3.0 years (range, 0.7 to eight years). Standard hip radiographs that included anteroposterior pelvic and frog-leg and cross-table lateral views were made of all patients. None of the patients had radiographic signs of arthritis. All four hips lacked femoral head-neck offset as seen on the cross-table lateral radiograph13, which suggested …

Nathan Copelan

Papers

Three-dimensional computed tomography of the hip in the assessment of femoroacetabular impingement

Three‐dimensional computed tomography of the hip in the assessment of femoroacetabular impingement

Magnetic resonance imaging with gadolinium arthrography to assess acetabular cartilage delamination. A report of four cases.