A CT study of the femoral and sciatic nerve periacetabular moving in different hip positions.

BACKGROUND: Femoral and sciatic nerves could be damaged during various stages of the periacetabular osteotomy. Changing the position of the hip could be the most effective way of preventing nerve injuries. The purpose of the present study was to investigate the distances of the nerves to various bony landmarks with different hip positions in computerized pelvic scanograms of healthy adults. MATERIALS AND METHODS: Fifteen healthy male adults (30 hips) (age 30 ± 6) were included. Scans were performed at three different hip positions measured by goniometer (neutral "N," flexion (30-45°) + abduction (30-45°) + external rotation (20°) "F" and neutral+ abduction (30-45°) + external rotation (20°) (Nabext) at three different levels (sourcil "1," the middle of the femoral head "2," and lower border of triradiate cartilage "3." RESULTS: At the sourcil level, the femoral nerve was found to be the furthest distance from the anterior acetabulum in the neutral position compared to flexion or neutral plus abduction, external rotation (p < 0.001). For the sciatic nerve, at level 2, hip flexion resulted in a greater distance than in the neutral position (p = 0.001). For level 3, hip flexion caused a decrease in the distance of the sciatic nerve to the acetabulum compared to both neutral positions (N or Nabex) (p = 0.001). CONCLUSIONS: During a pubic cut of the osteotomy, the femoral nerve moves closer to the anterior acetabulum wall with hip flexion or abduction plus external rotation. During an ischial cut, the sciatic nerve gets closer to the ischium with hip flexion while it moves away from the bone during retroacetabular cut. Level-III Study.

Anterior acetabular retractors and the femoral neurovascular bundle in anterior total hip arthroplasty: a cadaveric study.

PURPOSE: The direct anterior approach for primary total hip arthroplasty (THA) has become increasingly popular in recent years. Nerve compression or traction with a retractor is a common cause of nerve injury in this approach. The purpose of this cadaveric study was to evaluate the anatomic relationship of the femoral neurovascular bundle to the anterior acetabular retractor during direct anterior approach THA. METHODS: Eleven fresh-frozen cadavers underwent a standard direct anterior THA, with placement of an anterior acetabular retractor in the usual fashion between the iliopsoas and acetabulum for visualization during acetabular preparation. Careful dissection of the femoral triangle was performed, and the distances from the anterior retractor tip to the femoral nerve, artery, and vein were recorded and analyzed as mean distance ± standard deviation. RESULTS: In all 11 cadavers, the retractor tip was medial to the femoral nerve. The mean distance from retractor tip to femoral artery and vein was 5.9 mm (SD = 5.5, range 0-20) and 12.6 mm (SD 0.7, range 0-35), respectively. CONCLUSIONS: Surgeons should be aware of the proximity of the neurovascular structures in relation to the anterior acetabular retractor in the direct anterior approach, taking care to avoid perforating the iliopsoas muscle during retractor insertion and limit excessive traction to prevent nerve injury.

Acetabular labrum of hip joint in osteoarthritis: A qualitative original study and short review of the literature.

PURPOSE: Histological architecture of normal acetabular labrum regarding free nerve endings (FNEs) and mechanoreceptors (MRs) has been satisfactorily described in the literature. However, the presence of FNEs and MRs in acetabular labrum of hip joint has been analyzed only once in patients with osteoarthritis (OA). Aim of this article is to report histological distribution pattern of FNEs and MRs in acetabular labrum of patients with severe OA, at the same time conducting a comparison with normal acetabular labrum described in the literature. METHODS: Seven patients with severe hip OA were enrolled in this study. Patient selection was assisted by the utilization of specific clinical scales delineated by the American College of Rheumatology. After successful total hip arthroplasty, tissue samples of acetabular labra of seven patients were histologically processed and stained with the gold standard chloride method, which was subsequently examined under a compound microscope. RESULTS: FNEs and MRs constituted the major histological structures. Identified MRs included Pacini corpuscles, Ruffini corpuscles, and Golgi-Mazzoni corpuscles. The presence of FNEs was predominant in the middle part of the acetabular labrum, featuring a remarkable decrease in peripheral parts. In contrast, MRs were detected basically in peripheral parts and less in the middle part. CONCLUSIONS: Differentiation of the distribution pattern of MRs and FNEs in acetabular labrum of hip joint is remarkable between normal patients and patients with severe OA. The abundance of FNEs in the middle part of the pathologic labrum is mainly responsible for the observed discrimination. A "conversion" of MRs to FNEs may occur during OA progression, modulating therefore this pattern as well as the upcoming clinical manifestations.

The innervation of the human acetabular labrum and hip joint: an anatomic study.

BACKGROUND: The aim of the current study was to evaluate the innervation of the acetabular labrum in the various zones and to understand its potential role in nociception and proprioception in hips with labral pathology. METHODS: A total of twenty hip labrums were tagged and excised intraoperatively from patients undergoing a total hip replacement. After preparation, the specimens were cut to a thickness of 10 µm and divided into four quadrants (zones) using a clock face pattern. Neurosensory structure distribution was then evaluated using Hematoxylin and Eosin (H and E), and immunoreactivity to S-100. RESULTS: All specimens had abundant free nerve endings (FNEs). These were seen predominantly superficially and on the chondral side of the labrum. In addition, predominantly three different types of nerve end organs (NEOs) were identified in all twenty specimens. FNEs and NEOs were more frequently seen in the antero-superior and postero-superior zones. Four specimens had abundant vascularity and disorganised architecture of FNEs in the deeper zones of the antero-superior quadrant suggestive of a healed tear. Myofibroblasts were present in abundance in all the labral specimens and were distributed uniformly throughout all labral zones and depth. CONCLUSIONS: The current study shows that the human acetabular labrum has abundant FNEs and NEOs. These are more abundant in the antero-superior and postero-superior zones. The labrum, by virtue of its neural innervation, can potentially mediate pain as well as proprioception of the hip joint, and be involved in neurosecretion that can influence connective tissue repair.

The distribution of nociceptive innervation in the painful hip: a histological investigation.

Our understanding of the origin of hip pain in degenerative disorders of the hip, including primary osteoarthritis, avascular necrosis and femoroacetabular impingement (FAI), is limited. We undertook a histological investigation of the nociceptive innervation of the acetabular labrum, ligamentum teres and capsule of the hip, in order to prove pain- and proprioceptive-associated marker expression. These structures were isolated from 57 patients who had undergone elective hip surgery (44 labral samples, 33 ligamentum teres specimens, 34 capsular samples; in 19 patients all three structures were harvested). A total of 15,000 histological sections were prepared that were investigated immunohistochemically for the presence of protein S-100, 68 kDa neurofilament, neuropeptide Y, nociceptin and substance P. The tissues were evaluated in six representative areas. Within the labrum, pain-associated free nerve ending expression was located predominantly at its base, decreasing in the periphery. In contrast, the distribution within the ligamentum teres showed a high local concentration in the centre. The hip capsule had an almost homogeneous marker expression in all investigated areas. This study showed characteristic distribution profiles of nociceptive and pain-related nerve fibres, which may help in understanding the origin of hip pain.

Importancia de la relación anatómica entre el nervio isquiático y el margen posterior del acetábulo en la luxación posterior de la cadera / Anatomic value of the sciatic nerve with the posterior margin of the acetabulum in posterior dislocation of the hip

La luxación posterior de la articulación de la cadera es un trauma que puede sufrir una buena parte de la población, donde se puede comprometer el nervio isquiático, produciendo serios problemas en la vida del individuo afectado. El conocimiento de la relación anatómica entre el nervio isquiático y el margen posterior del acetábulo propiciará um diagnóstico preciso y precoz de esta lesión. Con el objetivo de estudiar la relación topográfica del nervio isquiático con el margen posterior del acetábulo y entregar antecedentes anatómicos para las cirugías ortopédicas en caso de luxaciones posteriores de la cadera, se estudiaron 40 miembros inferiores formolizados, de cadáveres humanos, adultos y de ambos sexos, localizados en los laboratorios de anatomía topográfica de la Universidad Estadual de Ciencias de la Salud de Alagoas, Brasil. En 19 miembros inferiores (47,7 por ciento) el nervio isquiático pasó directamente sobre el margen posterior del acetábulo y en los 21 restantes (53,3 por ciento), el nervio estuvo distante del margen mencionado, distancia que varió de 6 a 49 mm. Los resultados obtenidos muestran la estrecha relación entre el nervio isquiático y el margen acetabular, lo que acrecienta la posibilidad de lesión del nervio em los casos de luxación posterior de la cadera...

The posterior dislocation of the hip joint is a trauma that can undergo a large part of the population, which may compromise the sciatic nerve, causing serious problems in the life of the affected individual. Knowledge of the anatomical relationship between the sciatic nerve and the posterior margin of the acetabulum will facilitate accurate diagnosis and early um this injury. In order to study the topographical relationship of the sciatic nerve with the posterior margin of the acetabulum and provide background for orthopedic anatomical in posterior dislocations of the hip were studied 40 lower limbs formolized human cadavers, adults of both sexes , located in the topographical anatomy laboratories of the Universidade Estadual de Ciencias da Saude, Alagoas, Brasil. In 19 limbs (47.7 percent) sciatic nerve passed directly over the posterior margin of the acetabulum and the remaining 21 (53.3 percent), the nerve passed distal to the acetabular margin, distance ranging from 6-49 mm. The results show the close relationship between the sciatic nerve and the acetabular margin, which increases the possibility of nerve injury in posterior dislocation of the hip...

Radiculopathy as a manifestation of Langerhans' cell histiocytosis.

Langerhans' cell histiocytosis (LCH) is a rare condition of children and young adults in which Langerhans' cells proliferate. The clinical spectrum ranges from solitary or few focal lesions to multisystem involvement mimicking vasculitis or hematological malignancy. Focal bone lesions, known as eosinophilic granulomas, are the most common manifestations. Eosinophilic granuloma usually presents with a variable combination of pain, swelling, fracture, and fever. Facial bone involvement may manifest as an ear discharge, hearing loss, or exophthalmos. Nerve root pain is rarely reported, even in patients with lesions in the axial skeleton. We report four cases of nerve root pain caused by LCH. Two male patients aged 25 and 34 years, respectively, presented with truncated femoral neuralgia related to acetabular granulomas. A 25-year-old woman with involvement of the L5 vertebral body and a 41-year-old man with a sacral lesion presented with sciatica.

Acetabular anatomy and transacetabular screw fixation at the high hip center.

A quadrant system that defines the safe acetabular locations for screw placement exists for the anatomic hip center. We wanted to develop a similar system for the high hip center. The purposes of our study were to identify the anatomic structures at risk during placement of transacetabular screws in the high hip center, to identify maximum bone depth for screw purchase, and to determine if a high hip center quadrant system could be validated to guide placement of screws during acetabular arthroplasty. For this cadaver study of nine pelves, an acetabulum was reamed superiorly into the high hip center a distance equal to (1/2) of the native acetabular diameter. Screws exiting the acetabular bone by 15 mm were inserted before a computed tomography scan and a precise anatomic dissection were done. Structures at risk of penetration by screws include the external iliac vessels, the obturator nerve and vessels, the superior gluteal nerve and vessels, and the sciatic nerve. We found that a quadrant system at the high hip center can demarcate safe zones for screw placement. At the high hip center, only the peripheral (1/2) of the posterior quadrants are safe for screw placement.

[Localization of the neurokinin 1 receptor in hip joints of patients with painful osteoarthritis]. / Die Lokalisation des Neurokinin 1-Rezeptors im Hüftgelenk von Patienten mit schmerzhafter Osteoarthrose.

INTRODUCTION: Recent studies on osteoarthritis have focused on nociceptive substance P (SP) containing afferent nerve fibres. The effects of SP are known to be mainly mediated by the tachykinin receptor neurokinin 1 (NK1-R). AIM: The aim of the present study was to demonstrate the NK1-R in human joint tissues. METHODS: The hip joint capsule of three patients with painful hip osteoarthritis (Group 1), three patients with femoral neck fracture showing no cartilage destruction (Group 2, controls) and the soft tissue of the fossa acetabuli of Group 1 were resected during hip arthroplasty implantation. The tissue samples were cut into small blocks and immersion-fixed in Zamboni's fixative. The specimens were frozen, cut into 50 microm sections and immunostained using a standard immunohistochemical staining protocol. RESULTS: In Groups 1 and 2 the NK1-receptor was localised in the wall of venous vessels, on Schwann cells of nerve bundles and on nerve fibres. In the osteoarthritis group the staining pattern was similar but the number of NK1-bearing cell structures seemed to be enhanced. CONCLUSIONS: The present study provides the first evidence of NK1-R in the human hip joint. In patients with painful osteoarthritis the density of NK1-R-positive cell structures seemed to be increased. The localisation of the NK1 receptor on different cell types suggests multiple effects of SP in normal and osteoarthritic joints.

Fractures of the posterior wall of the acetabulum.

Only 30% of posterior-wall acetabular fractures involve a single large fragment. The majority are multifragmentary or have areas of impaction. Unsatisfactory clinical results occur in more than 80% of patients treated non-surgically. Operative management usually offers the best chance of preserving long-term joint function, but only if an anatomically reconstructed acetabulum can be achieved without complication. The keys to surgical success include maintaining the viability of the fracture fragments and the femoral head itself, using bone grafts and buttress plating to support elevated and comminuted fragments, and protecting the neurovascular structures at risk. Complications can include sciatic nerve injury (incidence, 3% to 18%), heterotopic ossification (7% to 20%), and osteonecrosis of the femoral head (5% to 8%). Despite the relative simplicity of this acetabular fracture, unsatisfactory outcomes after surgical repair of the posterior wall occur in at least 18% to 32% of cases, results that are worse than for most of the other more complex acetabular fracture patterns.

Controversies in acetabular fractures.

Open reduction and internal fixation has become the standard of care for the treatment of most displaced acetabular fractures. As surgical techniques have become refined, long term results of surgical fixation have improved. During the past 10 to 15 years, several controversies have surfaced in the orthopaedic literature regarding the treatment of acetabular fractures. The recent literature regarding acetabular fixation was reviewed. Controversies include the most efficacious surgical approach for complex acetabular fractures; the effectiveness of intraoperative sciatic nerve monitoring; the most effective method of prophylaxis against deep vein thrombosis; and the indications for and method of prophylaxis against heterotopic bone formation.

The nerve endings of the acetabular labrum.

The nerve endings of the human acetabular labrum were investigated. Twenty-three acetabular labra were obtained from 24 fresh human cadavers, stained with Suzuki's silver impregnation and an immunohistochemical technique for neurogenic specific protein S-100, and examined by light and electron microscopy. Ramified free nerve endings were seen in all specimens by silver staining, and also were observed by the immunohistochemical technique for S-100 protein. Sensory nerve end organs, such as a Vater-Pacini corpuscle, Golgi-Mazzoni corpuscle, Ruffini corpuscle, and articular corpuscle (Krause corpuscle), were observed by silver staining. Collagen fibers were scattered sparsely in the superficial layer of the labrum, and nerve endings were observed mostly in this region. Collagen fibers were sparse, and nerve endings also were observed in some regions among the collagen fiber bundles in the inner layer. Innervation of the acetabular labrum was confirmed in this study, suggesting that nerve endings in the labrum may be involved in nociceptive and proprioceptive mechanisms.