Vascular supply to the acetabular labrum

The acetabular labrum plays an important role in hip joint stability and protection of the articular cartilage of the hip. Despite this, few investigators have evaluated its microscopic vasculature and, to our knowledge, none has assessed its macroscopic blood supply. The purposes of this study were to identify the origin and course of the vascular supply to the acetabular labrum to determine if this blood supply is affected by a labral tear.

Surgical dislocation of the hip for the fixation of acetabular fractures

Surgical dislocation of the hip in the treatment of acetabular fractures allows the femoral head to be safely displaced from the acetabulum. This permits full intra-articular acetabular and femoral inspection for the evaluation and potential treatment of cartilage lesions of the labrum and femoral head, reduction of the fracture under direct vision and avoidance of intra-articular penetration with hardware. We report 60 patients with selected types of acetabular fracture who were treated using this approach. Six were lost to follow-up and the remaining 54 were available for clinical and radiological review at a mean follow-up of 4.4 years (2 to 9). Substantial damage to the intra-articular cartilage was found in the anteromedial portion of the femoral head and the posterosuperior aspect of the acetabulum. Labral lesions were predominantly seen in the posterior acetabular area. Anatomical reduction was achieved in 50 hips (93%) which was considerably higher than that seen in previous reports. There were no cases of avascular necrosis. Four patients subsequently required total hip replacement. Good or excellent results were achieved in 44 hips (81.5%). The cumulative eight-year survivorship was 89.0% (95% confidence interval 84.5 to 94.1). Significant predictors of poor outcome were involvement of the acetabular dome and lesions of the femoral cartilage greater than grade 2. The functional mid-term results were better than those of previous reports. Surgical dislocation of the hip allows accurate reduction and a predictable mid-term outcome in the management of these difficult injuries without the risk of the development of avascular necrosis.

Histology of damaged acetabular cartilage in symptomatic femoroacetabular impingement: an observational analysis

This prospective study on symptomatic adult patients with femoroacetabular impingement (FAI) who underwent open surgical intervention for management was designed to identify any obvious histological differences in the damaged acetabular cartilage within different subgroups of FAI. 20 patients underwent surgical intervention following safe surgical dislocation of the hip. There were 6 cases of cam impingement, 5 cases of pincer impingement and 9 of the mixed type. Pincer impingement cases demonstrated a characteristic focal, well-circumscribed and localized area of severe damage. On the other hand, cases with cam impingement showed a diffuse area of involvement affecting a larger surface of the acetabular cartilage, with degenerative changes, superficial erosions and some discontinuities. A small biopsy specimen of the acetabular rim including bone, cartilage and labrum from the affected zone was obtained in all cases. Histological evaluation was performed under normal and polarized light microscopy. Histological findings helped corroborate the pre-operative diagnosis and also define the unique nature of impingement and specific damage according to the type of impingement.

Hip capsule dimensions in patients with femoroacetabular impingement: a pilot study

Joint-preserving hip surgery, either arthroscopic or open, increasingly is used for the treatment of symptomatic femoroacetabular impingement (FAI). As a consequence of surgery, thickening of the joint capsule and intraarticular adhesions between the labrum and joint capsule and between the femoral neck and the joint capsule have been observed. These alterations are believed to cause persistent pain and reduced range of motion. Because the diagnosis is made with MR arthrography, knowledge of the normal capsular anatomy and thickness on MRI in patients is important. To date there is no such information available.

Effect of vagus nerve stimulation in an adult patient with Dravet syndrome: contribution to sudden unexpected death in epilepsy risk reduction?

We report on a patient who developed, from 5 months of age, multiple seizure types, including myoclonic, associated with severe psychomotor delay, leading to the diagnosis of Dravet syndrome. Over the years, he developed refractory epilepsy and was implanted with a vagus nerve stimulator at the age of 19. After 3 months, he experienced a progressive improvement of partial and generalized seizures, with a >90% reduction, and better alertness. This meaningful clinical improvement is discussed in the light of the sudden unexpected death in epilepsy risk, which is high in this setting, and seems remarkably diminished in our patient in view of the reduction of generalized convulsions.

Treatment of femoro-acetabular impingement: preliminary results of labral refixation

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'Aubigné clinical score and the Tönnis 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.

[Femoroacetabular impingement: trigger for the development of coxarthrosis]

Femoroacetabular impingement (FAI) is frequent; the estimated prevalence ranges between 10 and 15%. Our 10-years experience strongly suggests that FAI leads to osteoarthritis. Isolated acetabular or femoral abnormalities are rare, even though in women acetabular and in men femoral abnormalities predominate. Normal radiographs do not exclude the presence of FAI. Symptoms are related to the degree of deformity and occur earlier in the presence of activities requiring high levels of motion. The majority of patients with FAI are under the age of 40 years.In contrast to impingement in total hip replacement, the natural hip is under much higher constraint, not allowing to escape from impingement-induced shear forces by subluxation or complete dislocation. FAI-induced shear forces due to an aspherical femoral head/neck (cam type) are therefore high, causing outside-in damage with cleavage lesions of the acetabular cartilage by forced flexion and internal rotation. The cartilage of the femoral head remains initially intact, which cannot be explained by the classic concept of osteoarthritis. After the femoral head has migrated into the acetabular cartilage defect, vertical forces contribute to the further course of osteoarthritis. Tears between the labrum and cartilage, as seen by MRI, are not avulsions of the labrum from the cartilage but rather outside-in avulsions of the cartilage from the labrum. In acetabular overcoverage (pincer type) the labrum is the first structure to fail and acetabular cartilage damage develops thereafter.The treatment of FAI in patients under the age of 40 years is aimed at joint preservation. The clinical result is worse in the presence of significant cartilage damage. Therefore, early appreciation of FAI and timely therapeutic intervention as well as professional and athletic adjustment are important if osteoarthritis is to be prevented.

Hip arthroscopy after previous surgical hip dislocation for femoroacetabular impingement

PURPOSE: The purpose of this study was to examine whether arthroscopic adhesiolysis can relieve symptoms of patients with persistent pain after open surgical hip dislocation for femoroacetabular impingement syndrome without osseous or cartilaginous alterations. METHODS: This study comprised 16 consecutive patients (6 men and 10 women; mean age, 33.5 years [range, 19 to 60 years]) with persistent pain without osseous or cartilaginous alterations after surgical hip dislocation for the treatment of femoroacetabular impingement. At index surgery, all patients had osteochondroplasty of the head-neck junction and resection of the acetabular rim with reattachment of the labrum in 9 cases. All patients had preoperative magnetic resonance imaging-arthrogram and were treated with arthroscopy of the hip. RESULTS: At arthroscopy, all reattached labra were stable. In the cases without preservation of the labrum at the index operation, the joint capsule was attached at the level of the acetabular rim and synovitis was noticed. All patients had adhesions between the neck of the femur and joint capsule or between the labrum and capsule. In 3 patients the arthroscopic procedure was technically limited by massive thickening of the capsule. Overall, 81% of patients (13/16) showed less pain or were pain-free. The Merle d'Aubigné score improved from 13 points preoperatively to 16 points at the last follow-up. CONCLUSIONS: Persistent pain after surgical dislocation of the hip without evidence of cartilaginous and osseous alterations could result from intra-articular adhesions. Hip arthroscopy after previous surgery can be demanding because of scarring. If the adhesions can be released, good results can be achieved. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Treatment of femoro-acetabular impingement: preliminary results of labral refixation. Surgical technique

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'Aubigné clinical score and the Tönnis 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.

Magnetic resonance imaging of the hip at 3 Tesla: clinical value in femoroacetabular impingement of the hip and current concepts

Magnetic resonance imaging (MRI) is the most promising noninvasive modality for hip joint evaluation, but it has limitations in diagnosing cartilage lesion and acetabular labrum changes, especially in early stages. This is significant due to superior outcome results of surgery intervention in hip dysplasia or femoroacetabular impingement in patients not exceeding early degeneration. This emphasizes the need for accurate and reproducible methods in evaluating cartilage structure. In this article, we discuss the impact of the most recent technological advance in MRI, namely the advantage of 3-T imaging, on diagnostic imaging of the hip. Limitations of standard imaging techniques are shown with emphasis on femoroacetabular impingement. Clinical imaging examples and biochemical techniques are presented that need to be further evaluated.

Hip damage occurs at the zone of femoroacetabular impingement

Although current concepts of anterior femoroacetabular impingement predict damage in the labrum and the cartilage, the actual joint damage has not been verified by computer simulation. We retrospectively compared the intraoperative locations of labral and cartilage damage of 40 hips during surgical dislocation for cam or pincer type femoroacetabular impingement (Group I) with the locations of femoroacetabular impingement in 15 additional hips using computer simulation (Group II). We found no difference between the mean locations of the chondrolabral damage of Group I and the computed impingement zone of Group II. The standard deviation was larger for measures of articular damage from Group I in comparison to the computed values of Group II. The most severe hip damage occurred at the zone of highest probability of femoroacetabular impact, typically in the anterosuperior quadrant of the acetabulum for both cam and pincer type femoroacetabular impingements. However, the extent of joint damage along the acetabular rim was larger intraoperatively than that observed on the images of the 3-D joint simulations. We concluded femoroacetabular impingement mechanism contributes to early osteoarthritis including labral lesions. LEVEL OF EVIDENCE: Level II, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Radiologische Diagnose des femoroazetabuläre Impingements [Radiological diagnosis of femoroacetabular impingement]

Femoroacetabular impingements (FAI) are due to an anatomical disproportion between the proximal femur and the acetabulum which causes premature wear of the joint surfaces. An operation is often necessary in order to relieve symptoms such as limited movement and pain as well as to prevent or slow down the degenerative process. The result is dependent on the preoperative status of the joint with poor results for advanced arthritis of the hip joint. This explains the necessity for an accurate diagnosis in order to recognize early stages of damage to the joint. The diagnosis of FAI includes clinical examination, X-ray examination and magnetic resonance imaging (MRI). The standard X-radiological examination for FAI is carried out using two X-ray images, an anterior-posterior view of the pelvis and a lateral view of the proximal femur, such as the cross-table lateral or Lauenstein projections. It is necessary that positioning criteria are adhered to in order to avoid distortion artifacts. MRI permits an examination of the pelvis on three levels and should also include radial planned sequences for improved representation of peripheral structures, such as the labrum and peripheral cartilage. The use of contrast medium for a direct MR arthrogram has proved to be advantageous particularly for representation of labrum damage. The data with respect to cartilage imaging are still unclear. Further developments in technology, such as biochemical-sensitive MRI applications, will be able to improve the diagnosis of the pelvis in the near future.

Therapie des femoroazetabulären Impingements über die chirurgische Hüftluxation [Surgical dislocation of the hip for the treatment of femoroacetabular impingement. Technique and results]

Surgical dislocation of the hip is a safe and established technique for treating femoroacetabular impingement. The complication rate is low, and if the correct technique that respects the blood supply is used, femoral head necrosis does not occur. The most frequent complications are minor ectopic bone formation and nonunion of the greater trochanter. Surgical treatment includes the correction of femoral and acetabular pathology. Clinically, in approximately 75-80% of cases a good-to-excellent result can be obtained. However, patients with advanced degenerative changes (exceeding stage 1 osteoarthritis using the Tönnis score) have worse outcomes. It has also been shown that preservation of the labrum has a significant influence on both clinical outcome and progression of osteoarthritis: It seems that preservation of the labrum is mandatory.

How accurately can the acetabular rim be trimmed in hip arthroscopy for pincer-type femoral acetabular impingement: a cadaveric investigation

PURPOSE: The purpose of this study was to evaluate the precision of central hip arthroscopy in the assessment and treatment of pincer-type femoroacetabular impingement (FAI) avoiding the posterolateral portal, with its close proximity to the main arterial blood supply of the femoral head, the medial circumflex femoral artery. METHODS: Seven human cadaveric hips underwent arthroscopic trimming of the acetabular labrum and rim along a preoperatively defined 105 degrees arc of resection for treatment of a presumed pincer-type lesion. After the arthroscopic procedure, all specimens were dissected and measured for evaluation of the location, quantity, and quality of the area undergoing resection. RESULTS: The difference between the actual and planned arc of resection was 18.7 degrees +/- 4.7 degrees (range, 2 degrees to 34 degrees). This was mainly because of a lack of accuracy in the presumed posterior starting point (PSP), with a mean deviation of 19 degrees +/- 3.4 degrees (range, 10 degrees to 36 degrees). Correlation analysis showed that variance in the arc of resection was mainly dependent on the PSP (r = 0.739, P = .058). CONCLUSIONS: Central hip arthroscopy is a feasible option in treating anterosuperior pincer-type FAI by use of the anterior and anterolateral portals only. This cadaveric study showed that there is a significant risk of underestimating the actual arc of resection compared with the planned arc of resection for posterosuperior pincer-type lesions because of the modest accuracy in determining the PSP of the resection. CLINICAL RELEVANCE: Accurate preoperative planning and arthroscopic identification of anatomic landmarks at the acetabular side are crucial for the definition of the appropriate starting and ending points in the treatment of pincer-type FAI. Whereas anterosuperior pincer-type lesions can be addressed very precisely with our technique, the actual resection of posterosuperior lesions averaged 19 degrees less than the planned resection, which may have clinical implications.

The effects of impingement and dysplasia on stress distributions in the hip joint during sitting and walking: a finite element analysis

Soft tissue damage has been observed in hip joints with pathological geometries. Our primary goal was to study the relationship between morphological variations of the bony components of the hip and resultant stresses within the soft tissues of the joint during routine daily activities. The secondary goal was to find the range of morphological parameters in which stresses are minimized. Computational models of normal and pathological joints were developed based on variations of morphological parameters of the femoral head (Alpha angle) and acetabulum (CE angle). The Alpha angle was varied between 40 degrees (normal joint) and 80 degrees (cam joint). The CE angle was varied between 0 degrees (dysplastic joint) and 40 degrees (pincer joint). Dynamic loads and motions for walking and standing to sitting were applied to all joint configurations. Contact pressures and stresses were calculated and crosscompared to evaluate the influence of morphology. The stresses in the soft tissues depended strongly on the head and acetabular geometry. For the dysplastic joint, walking produced high acetabular rim stresses. Conversely, for impinging joints, standing-to-sitting activities that involved extensive motion were critical, inducing excessive distortion and shearing of the tissue-bone interface. Zones with high von Mises stresses corresponded with clinically observed damage zones in the acetabular cartilage and labrum. Hip joint morphological parameters that minimized were 20 degrees