Femoroacetabular impingement: bone marrow oedema associated with fibrocystic change of the femoral head and neck junction

Atypical hip pain: coexistence of femoroacetabular impingement (FAI) and osteoid osteoma

The objective of this article was to emphasize the importance of including less common causes of hip pain in a differential diagnosis, particularly when clinical and radiographic variables are atypical. This article presents the case of a 52-year-old patient with a history of progressive hip pain resulting from the coexistence of both a femoroacetabular impingement (FAI) and an intraarticular osteoid osteoma. The intraarticular osteoid osteoma was initially overlooked due to its unremarkable features on radiographic and resonance imaging. Consequently, the patient was surgically treated for FAI with only partial relief. An osteolytic nidus characteristic of osteoid osteoma was discovered only 1.5 years following surgery. The patient was subsequently treated for osteoid osteoma with anti-inflammatories, after which his pain began to resolve. The patient was completely pain free after 7 months. Level of evidence V.

MRI findings of new uptake in the femoral head detected on follow-up bone scans

OBJECTIVE. The purpose of this article is to suggest clinical indications for MRI in patients with breast cancer who have new uptake lesions in the femoral head on follow-up bone scans, by evaluating the incidence and causes of new uptake lesions. MATERIALS AND METHODS. Between January 2002 and July 2013, a total of 145 patients with breast cancer who showed new uptake in the femoral head on follow-up bone scans were included in our study. They were classified into two groups: group 1 consisted of 125 patients without known bone metastases, and group 2 consisted of 20 patients who already had bone metastases other than that in the femoral head. The Fisher exact test was performed for the statistical analysis. Thereafter, we reviewed MR images for characterization of the new abnormal uptake in the femoral head. RESULTS. New uptake lesions in the femoral head were metastatic in only 4.8% (6/125) of group 1 patients but in 75% (15/20) of group 2 patients (p < 0.0001). In both groups, no patient with a single uptake lesion in the femoral head had bone metastasis, whereas all patients with more than five new uptake lesions, including those of the femoral head, showed bone metastasis. Most MRI diagnoses for new uptake in the femoral head were fibrocystic change (15/30, 50%) and subchondral fracture (11/30, 36.7%). CONCLUSION. Most of the new uptake lesions in the femoral head detected on the follow-up bone scans in patients with breast cancer were benign. However, MRI could be considered in patients with known bone metastasis or with multiple new uptake lesions on bone scans.

Radiofrequency thermal ablation of osteoid osteomas of the proximal femur. Usefulness of ultrasound guidance in selected cases

PURPOSE

To review symptoms and imaging findings of proximal femoral osteoid osteomas (OO); to analyse the results of a thermal ablation technique for radiofrequency of the nidus in this location; and to describe usefulness of ultrasound guidance in selected cases.

MATERIAL AND METHOD

Descriptive and retrospective study consisting of 8 patients with OO in the proximal epiphysis of the femur, which were treated by thermal ablation of the nidus with radiofrequency waves from 1998 to 2004.

RESULTS

The mean pain period until the performance of the thermal ablation was 11.5 months (range 5-18 months). There were no complications, and all patients stated that the pain was gone by the day following the procedure, with some discomfort during the first week, except for one where it lasted more than one month due to technique difficulties. At present, with a mean follow up of 6 years and 2 months (range 6-190 months), all patients remain asymptomatic and live a rigorous normal life.

DISCUSSION

Thermal ablation with CT-guided radiofrequency waves is a safe, effective and efficient procedure.

CONCLUSION

Normal appearance of a proximal femoral OO does not differ significantly from other location osteomas and its diagnosis is easier with previous knowledge. Thermal ablation of the nidus with radiofrequency waves, that may be performed using ultrasound guidance, appears to be the elective treatment of choice due to its efficiency and minimum morbidity.

Correlation between the prevalence of herniation pits and the α angle of the hip: computed tomography evaluation in healthy Chinese adults

Background

Herniation pits (HPs) commonly develop over time at the femoral head–neck junction in adults, but their cause is still under debate. The purpose of study reported here was to investigate the correlation between the prevalence of HPs of the femoral neck and the alpha angle of the hips of healthy Chinese adults, by using computed tomography (CT).

Methods

Six hundred and seventy Chinese adults (representing 1145 hips) who had no known diseases affecting the proximal femur and had no symptoms of femoroacetabular impingement underwent a 64-slice CT scan for medical purposes that included the hip in the scan range. Their CT data were analyzed for the prevalence of HPs in the femoral necks and for hip alpha angles.

Results

The overall prevalence of femoral-neck HPs was 12.5% (143 of 1145 hips). The prevalence in the left versus right femoral necks was 12.1% (69 of 569 hips) versus 12.8% (74 of 576 hips). There was no statistically significant difference between the two sides (χ² = 0.136; p = 0.712). The prevalence of HPs was greater in men than in women (15.9% vs 7.7%; p < 0.01) and greater in adults older than 30 years than in adults younger than 30 years (χ²= 14.547; p < 0.01). The alpha angles were greater in the 143 proximal femora with HPs than in the 1002 without pits (39.95° ± 6.01° vs 37.97° ± 5.14°; p < 0.01).

Conclusions

The prevalence of HPs of the femoral neck in healthy adults was 12.5%, and the prevalence was greater in men than in women. There is a correlation between the prevalence of HPs and the contour of the femoral head–neck junction. The formation of pits may be attributed to the combination of degeneration and morphologic variances in the femoral head–neck junction.

MR imaging of the hip: pathologies and morphologies of the hip joint, what the surgeon wants to know

MR imaging of the hip is frequently used in symptomatic patients before hip preservation surgery; it is used as a decision-making tool and as a planning tool. The MRI can confirm the preliminary working diagnosis, identify other possible sources of pain, and highlight anatomic areas that are not routinely viewed during surgery. In addition, MR imaging is capable of illustrating normal and abnormal bony morphology of the femur and pelvis; and in the case that arthrography is used, diagnostic injection can be administrated concurrently. This article highlights a surgeon's perspective on the use of MR imaging in the patient with nonarthritic hip pain.

Sex differences of hip morphology in young adults with hip pain and labral tears

PURPOSE

To compare hip morphology between young men and women who presented with hip pain and labral tears.

METHODS

A retrospective review of our hip arthroscopy registry from March 2008 to June 2010 was completed. We identified 217 patients (249 hips) who were between the ages of 18 to 30 years. The inclusion criteria were (1) insidious-onset hip pain or worsening pain after low-energy sports trauma, (2) positive hip impingement sign, (3) Tönnis grades 0 to 1, (4) magnetic resonance imaging showing labral tear, and (5) primary hip arthroscopy confirming labral tear. Forty-five patients (52 hips) were excluded for the following reasons: (1) revision hip arthroscopy, (2) high-energy hip trauma, (3) history of surgery involving the femur or pelvis, (4) previous fractures of the femur or pelvis, (5) Tönnis grades 2 or above, (6) proliferative disease of the hip (i.e., synovial chondromatosis, pigmented villonodular synovitis), (7) neuromuscular disease (i.e., cerebral palsy), and (8) deformities related to Legg-Calvé-Perthes disease or developmental dysplasia of the hip. Therefore, the cohort study group included 105 (61%) men (123 [62.4%] hips) and 67 (39%) women (74 [37.6%] hips). Sex comparisons were made for the following variables measured on preoperative hip computed tomography scans: alpha angle, acetabular version, femoral version, lateral center-edge angle, and neck-shaft angle.

RESULTS

Women had smaller alpha angles (47.8°v 63.6°, P < .001), increased acetabular version (17.3°v 13.9°, P < .001), and increased femoral anteversion (14.4°v 12.1°, P = .05).

CONCLUSIONS

In young adults with hip pain and labral tears, women have smaller alpha angles and hips that are generally more anteverted. Therefore, in women, cam lesions may be more subtle, preoperative hip version analyses should be encouraged, and rim trimming may need to be cautiously planned to avoid increasing contact stresses at weight-bearing areas after such a procedure.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Herniation pits in human mummies: a CT investigation in the Capuchin Catacombs of Palermo, Sicily

Herniation pits (HPs) of the femoral neck were first described in a radiological publication in 1982 as round to oval radiolucencies in the proximal superior quadrant of the femoral neck on anteroposterior radiographs of adults. In following early clinical publications, HPs were generally recognized as an incidental finding. In contrast, in current clinical literature they are mentioned in the context of femoroacetabular impingement (FAI) of the hip joint, which is known to cause osteoarthritis (OA). The significance of HPs in chronic skeletal disorders such as OA is still unclear, but they are discussed as a possible radiological indicator for FAI in a large part of clinical studies.

In this paleoradiological study we examined a sample of mummies from the Capuchin Catacombs of Palermo, Sicily, by a mobile computed tomography (CT) scanner. Evaluation of the CT examinations revealed HPs in six out of 16 (37.5%) adult male mummies.

The first aim of this study was to compare the characteristics of HPs shown in our mummy collection to the findings described in clinical literature. Thereby CT evaluation revealed that their osseous imaging characteristics are in accordance, consisting of round to oval subcortical lesions at the anterior femoral neck, clearly demarcated by a sclerotic margin.

The second aim was to introduce HPs to the paleoradiological and paleopathological methodology as an entity that underwent a renaissance from an incidental finding to a possible radiological indicator of FAI in the clinical situation. As FAI plays an important role in the development of OA of the hip, which is a very common finding in human skeletal remains, HPs should always be considered in paleoradiological evaluation of hip joint diseases.

The case for cam surveillance: the arthroscopic detection of cam femoroacetabular impingement missed on preoperative imaging and its significance

Classification of femoroacetabular impingement is typically determined by preoperative imaging. Despite measurements such as the alpha angle and anterior offset ratio, cam dysmorphisms may be missed. We present 2 cases of femoroacetabular impingement classified as pincer subtypes where significant cam lesions were not detected until surgery. Arthroscopic cam surveillance includes the intentional visualization of the anterior and lateral proximal head-neck junctional region from the peripheral compartment performed with capsular retraction and/or partial capsulectomy. Static and dynamic cam surveillance of the proximal femur is recommended before the termination of surgery for hip chondrolabral dysfunction and has even greater significance in the arthroscopic management of these patients.

Herniation pits in the femoral neck: a radiographic indicator of femoroacetabular impingement?

The purpose was to assess the significance of herniation pits in the femoral neck for radiographic diagnosis of femoroacetabular impingement (FAI). Eighty hips in 62 patients (bilateral in 18) with neutral pelvic orientation were enrolled. Herniation pits were diagnosed when they were located at the anterosuperior femoral neck, close to the physis, and with a diameter of >3 mm. The five radiographic signs of FAI were used: lateral center edge angle (LCE) >39°, acetabular index (AI) ≤0, extrusion index (EI) <25%, acetabular retroversion, and pistol-grip deformity. Patients with radiographs suggesting FAI were retrospectively correlated with their clinical symptoms. Positive radiographic signs were observed in 7 hips with LCE, 7 with AI, and 80 with EI criteria. Only 3 hips out of 80 (3.8%) showed all of the signs. The acetabular retroversion and pistol-grip deformity were seen in 12/80 and 3/80 hips, respectively. The total number of hips that met radiographic criteria for FAI, including pincer type and cam type, was 18 (23%). However, none of these hips were clinically diagnosed with FAI. All symptomatic hips (11/80) presented only with nonspecific pain, and 2 hips out of 11 showed radiographic signs of FAI. The low frequency of positive radiographic signs suggesting FAI with related symptoms among patients with herniation pits suggests that herniation pits have limited significance in the diagnosis of FAI. Therefore it can be concluded that an incidental finding of herniation pits does not necessarily imply a correlation with FAI.

Hip and groin pain in adolescents

A variety of disorders may result in hip or groin pain, particularly in adolescents who partake in sports. Both intra-articular and extra-articular pathologies should be considered. We will review a select group of abnormalities that are gaining recognition in this age group.

Acetabular cartilage delamination in femoroacetabular impingement. Risk factors and magnetic resonance imaging diagnosis

BACKGROUND

Delamination of acetabular articular cartilage is a common abnormality in hips with femoroacetabular impingement. The purpose of the present study was to identify clinical and radiographic factors predisposing to delamination and to assess the diagnostic accuracy of magnetic resonance arthrography for the detection of these lesions.

METHODS

Following a retrospective review of records, we determined that acetabular cartilage delamination had been present in twenty-eight of sixty-four hips that had undergone a surgical dislocation procedure for the treatment of femoroacetabular impingement. Multivariable logistic regression was performed to assess the correlation of radiographic findings (i.e., magnetic resonance imaging and computerized tomography findings) with the status of delamination. The preoperative interpretations of the magnetic resonance arthrograms for twenty-seven hips that underwent surgical dislocation were reviewed to assess the accuracy of detecting delamination. At the time of surgery, nine of these twenty-seven hips were found to have delamination. Magnetic resonance arthrography interpretations that did not correlate with operative findings were subjected to conspicuity assessment and error analysis.

RESULTS

The rate of delamination of the acetabular cartilage as noted at the time of surgical dislocation was 44% (twenty-eight of sixty-four). Delamination was strongly associated with male sex and femoral sided signs of impingement; however, it was not associated with acetabular overcoverage (center-edge angle, >40 degrees) (odds ratio = 0.16; p < 0.05). While there was no significant difference in the prevalence of labral lesions between groups, whenever labral and delamination lesions were found in the same hip, they were directly adjacent to one another. Preoperative magnetic resonance arthrography had a low sensitivity for delamination (22%) but had a high specificity (100%). Two-thirds of the delamination lesions were visible on retrospective review of these images when the reader was unblinded to the surgical findings. Delamination could most often be identified on the sagittal T1-weighted image and on the proton-density sequences with fat saturation.

DISCUSSION

There should be a high level of suspicion for articular cartilage delamination in men and in patients with primarily cam-type femoroacetabular impingement. Acetabular overcoverage may be protective against delamination. Preoperative high-quality magnetic resonance arthrograms should be carefully analyzed for evidence of delamination in this patient population.