Sensory nerve endings in monkey hip joint capsule: a morphological investigation

Evaluation of the distribution of mechanoreceptors in the hip joint with severe coxarthrosis in 9 patients: A histologic and stereological study

Due to its high mobility, hip joint plays a crucial role in executing many movements such as standing, sitting, running, crouching. The distribution of mechanoreceptors and neural elements in anatomical structures that provide stabilization of the hip joint is important in determining the optimal surgical incision site for the hip joint stabilizers in patients with coxarthrosis. Various studies have been conducted about the mechanoreceptors and distribution of neural elements in structures such as the transvers acetabular ligament, teres (round) ligament of femur, acetabular labrum and hip joint capsule with using various staining methods. To our knowledge, there is insufficient information about the mechanoreceptor distribution within the anatomic structures that participate in stabilization of the hip joint. This study is planned to examine the distribution of mechanoreceptors in the transverse acetabular ligament, teres ligament, acetabular labrum and joint capsule in samples obtained during the surgery who are operated for hip replacement surgery due to severe coxarthrosis. Each specimen was stained with silver impregnation technique and density of mechanoreceptors were estimated by stereological method. Teres ligament has the highest number of mechanoreceptors among all other specimens. Within the joint capsule, mechanoreceptors were most abundant at its antero-inferior part, whereas its anterior part contained the lowest number of mechanoreceptors. These results suggest that, as the anterior part of hip capsule bears the lowest number of mechanoreceptors, it might be safer for incision during total hip arthroplasty surgery.

Histopathological Evaluation of Mechanoreceptors in the Metatarsophalangeal Joint Capsule in Hallux Valgus

To date, we could find no study concerning the relationship between mechanoreceptors in the joint capsule of the first metatarsophalangeal joint and hallux valgus deformity. We aimed to investigate the presence of mechanoreceptors in samples obtained from the first metatarsophalangeal joint capsules of patients with hallux valgus deformity to improve our understanding of the clinical and histopathological features of the disease. Samples were taken from the first metatarsophalangeal joint capsules of 13 fresh-frozen cadavers with normal anatomy (controls) and 29 patients undergoing surgery for hallux valgus (cases). For light microscopy, excised specimens were fixed in 10% formaldehyde and processed for routine histopathological investigation. All samples were dehydrated in a series of ethanol, cleared in xylene, and embedded in paraffin. Orientation of collagen fibers was determined on Masson's trichrome-stained sections, and mechanoreceptors were evaluated on S-100-immunostained sections. In the sections stained with Masson's trichrome, the orientation of collagen fibers was regular in the control group. However, coarse and disoriented collagen bundles were observed in the hallux valgus cases (P ≤ .05). S-100 immunostaining was positive in the sections of both the cases and controls. Finally, free nerve endings were more abundant in the samples obtained from the capsules of hallux valgus cases than from the control group (P ≤ .05). An increase in the number of free nerve endings within the capsules of the first metatarsophalangeal joints in feet with hallux valgus deformity might have a role in the development of clinically relevant joint pain and instability.

Topography of sensory receptors within the human glenohumeral joint capsule

BACKGROUND AND HYPOTHESES

Sensory receptors in the joint capsule are critical for maintaining joint stability. However, the distribution of sensory receptors in the glenohumeral joint of the shoulder, including mechanoreceptors and free nerve endings, has not been described yet. This study aimed to describe the distributions of different sensory receptor subtypes in the glenohumeral joint capsule. Our hypotheses were as follows: (1) Sensory receptor subtypes would differ in density but follow a similar distribution pattern, and (2) the anterior capsule would have the highest density of sensory receptors.

METHODS

Six glenohumeral joint capsules were harvested from the glenoid to the humeral attachment. The capsule was divided into 4 regions of interest (anterior, posterior, superior, and inferior) and analyzed using modified gold chloride stain. Sensory receptors as well as free nerve endings were identified and counted under a light microscope from sections of each region of interest. The density of each sensory receptor subtype was calculated relative to capsule volume.

RESULTS

Sensory receptors were distributed in the glenohumeral joint capsule with free nerve endings. The anterior capsule exhibited the highest median density of all 4 sensory receptors examined, followed by the superior, inferior, and posterior capsules. The median densities of these sensory receptor subtypes also significantly differed (P = .007), with type I (Ruffini corpuscles) receptors having the highest density (2.97 U/cm³), followed by type IV (free nerve endings, 2.25 U/cm³), type II (Pacinian corpuscles, 1.40 U/cm³), and type III (Golgi corpuscles, 0.24 U/cm³) receptors.

CONCLUSION

Sensory receptor subtypes are differentially expressed in the glenohumeral joint capsule, primarily type I and IV sensory receptors. The expression of sensory receptors was dominant in the anterior capsule, stressing the important role of proprioception feedback for joint stability. The surgical procedure for shoulder instability should consider the topography of sensory receptors to preserve or restore the proprioception of the shoulder joint.

Investigation of sensory nerve endings in pulvinar, ligamentum teres, and hip joint capsule: A prospective immunohistochemical study of 36 cases with developmental hip dysplasia

OBJECTIVE

The aim of this study was to immunohistochemically identify and characterize the presence of sensory nerve endings (SNEs) in pulvinar, ligamentum teres (LT), and hip joint capsule (HJC) of children with developmental dysplasia of the hip (DDH).

METHODS

Pulvinar, LT, and HJC specimens were obtained from 38 hips of 36 children (31 girls, five boys; mean age=49 months; age range=18-132 months) during open reduction surgery for DDH. All specimens underwent subsequent routine tissue processing (formalin fixation and paraffin embedding). To determine tissue morphology, haematoxylin and eosin staining was used. SNEs were analyzed immunohistochemically using a mouse monoclonal antibody against S-100 Beta Protein based on the classification of Freeman and Wyke including four types of SNEs including mechanoreceptors: type I Ruffini corpuscles, type II Pacini corpuscles, type III Golgi organs, and type IVa unmyelinated free nerve endings (FNEs). Additionally, children were sorted into three groups based on their age at the time of surgery: Group 1 (age <3 years; 19 hips of 18), Group 2 (age: 3-5 years; 10 hips of 10 children), and Group 3 (age >5 years; 9 hips of 8 children).

RESULTS

Although no Type I, II, or III SNEs were identified in any specimen, type IVa mechanoreceptor (FNEs) was immunohistochemically characterized in 13 (34%) pulvinar, 19 (50%) LT, and 16 (42%) HJC specimens. The total density of FNEs was 3.31±5.70)/50 mm2 (range 0-21) in pulvinar specimens, 3.18 ± 5.92)/50 mm2 (range 0-24) in HJC specimens, and 4.51±6.61/50 mm2 (range 0-22) in LT specimens. Furthermore, the operated side, gender, and the number of FNEs in specimens did not differ significantly among the age groups (p>0.05 for all), and the number of FNEs was not significantly correlated with age, gender, or the operated side (p>0.05 for all).

CONCLUSION

Evidence from this study revealed that pulvinar, LT, and HJC include only FNEs, which play a role in pain sensation, among mechanoreceptors. Surgical excision of these tissues may not cause a significant loss of sensory function in the hip joint of children with DDH.

LEVEL OF EVIDENCE

Level II, Therapeutic Study.

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.

Normal microscopic architecture of acetabular labrum of hip joint: a qualitative original study with clinical aspects

Background

Normal histologic architecture of acetabular labrum, regarding presence of Free Nerve Endings (FNEs) and Nerve End Organs (NEOs) has been four times described. Nevertheless, elderly cadaveric specimens and individuals were recruited, leading to considerably high unreliability probability due to microscopic degenerative alterations. Aim of this paper is to analyze distribution pattern of FNEs and NEOs in acetabular labra of healthy middle-aged individuals, configuring thus more reliably acetabular labrum microscopic profile.

Materials and methods

Six patients with middle age 52 ± 2.5 years were enrolled in this study. Injury of acetabular labrum and normal hip radiograph were present in all cases. Patients were all subjected to successful hip hemi-arthroplasty and derived acetabular labra were subsequently histologically processed and observed under a compound microscope.

Results

FNEs and NEOs were detected in all specimens. All types of NEOs were identified, including Paccini, Golgi-Mazzoni, Ruffini and Krause corpuscles. FNEs and NEOs were both in ventral part and in chondral side of labrum predominantly detected.

Conclusion

FNEs and NEOs presence was greater in ventral side of labrum, being thus in partial agreement with previous studies results. Further study is required, in order to elucidate the exact acetabular labrum normal microscopic anatomy.

Level of evidence

IV.

The Anthropoid Crista Trochanterica and the Hip Joint Capsule

The tubercle on the posterior aspect of the femoral neck (the crista trochanterica) has been repeatedly remarked upon because of its presence in early fossil apes, yet the function of this tubercle has eluded researchers. The prevailing explanation for the tubercle is that it relates to a strong ischiofemoral ligament, although none of the hypotheses for this bony projection have been systematically evaluated. This study surveyed 41 extant anthropoid species (n = 267 individuals) for the presence of a crista trochanterica. The soft tissue structures of the hip joint were then dissected and described for a sample of anthropoid cadavers (n = 14) in order to evaluate different hypotheses related to function of this tubercle. This study confirmed that the crista trochanterica is found in most cercopithecoids and platyrrhines, and is not present in great apes. The tubercle is rarely present in hylobatids, contrary to prior reports. The ischiofemoral ligament is not usually well-developed in anthropoids and does not fully explain the crista trochanterica morphology, although all cadavers displayed a well-developed zona orbicularis running along the posterior aspect of the joint capsule. The hip joint capsule itself inserted along the crista trochanterica in some individuals, typically those with an elongate crista trochanterica, but was highly variable in regards to the position of the tubercle. The hypotheses for the crista trochanterica are considered within the context of these findings, although the exact function of the tubercle remains unresolved.

Assessing Regeneration of Mechanoreceptors in Human Hip Pseudocapsule after Primary Total Hip Arthroplasty

Introduction

The aim of our study was to determine whether specific mechanoreceptors would regenerate in the pseudocapsule that had formed in place of the native capsule after primary total hip replacement (THR).

Methods

We studied 20 full-thickness samples of pseudocapsule tissue from patients undergoing revision THR surgery. All patients had had a partial capsulectomy during primary THR. The specimens were stained with haematoxylin and eosin and immunohistochemical dyes using a monoclonal antibody against S-100 protein.

Results

No mechanoreceptors were detected in the pseudocapsule of any of the specimens.

Conclusion

Our study concludes that if a partial capsulectomy is performed during primary THR, the replaced pseudocapsule will not have any active neurophysiological role in the hip. In this context, we recommend the preservation of hip joint capsule and an anatomical repair at the time of primary THR. Preservation of neurophysiologically viable tissue has been shown to reduce dislocation and may lead to better functional recovery.

In vivo baseline measurements of hip joint range of motion in suspensory and nonsuspensory anthropoids

Hominoids and atelines are known to use suspensory behaviors and are assumed to possess greater hip joint mobility than nonsuspensory monkeys, particularly for range of abduction. This assumption has greatly influenced how extant and fossil primate hip joint morphology has been interpreted, despite the fact that there are no data available on hip mobility in hominoids or Ateles. This study uses in vivo measurements to test the hypothesis that suspensory anthropoids have significantly greater ranges of hip joint mobility than nonsuspensory anthropoids. Passive hip joint mobility was measured on a large sample of anesthetized captive anthropoids (nonhuman hominids = 43, hylobatids = 6, cercopithecids = 43, Ateles = 6, and Cebus = 6). Angular and linear data were collected using goniometers and tape measures. Range of motion (ROM) data were analyzed for significant differences by locomotor group using ANOVA and phylogenetic regression. The data demonstrate that suspensory anthropoids are capable of significantly greater hip abduction and external rotation. Degree of flexion and internal rotation were not larger in the suspensory primates, indicating that suspension is not associated with a global increase in hip mobility. Future work should consider the role of external rotation in abduction ability, how the physical position of the distal limb segments are influenced by differences in ROM proximally, as well as focus on bony and soft tissue differences that enable or restrict abduction and external rotation at the anthropoid hip joint.

Sources of sensory innervation of the hip joint capsule in the rabbit - a retrograde tracing study

The aim of the study was to investigate the sensory innervation of the hip joint capsule in the rabbit. Individual animals were injected with retrograde fluorescent tracer Fast Blue (FB) into the lateral aspect of the left hip joint capsule (group LAT, n = 5) or into the medial aspect of the hip joint capsule (group MED, n = 5), respectively. FB-positive (FB+) neurons were found within ipsilateral lumbar (L) and sacral (S) dorsal root ganglia (DRG) from L7 to S2 (group LAT) and from L6 to S4 (group MED). They were round or oval in shape with a diameter of 20-90 μm. The neurons were evenly distributed throughout the ganglia. The average number of FB+ neurons was 16 ± 2.8 and 27.6 ± 3.5 in rabbits from LAT and MED, respectively. The largest average number of FB+ neurons in animals of group LAT was found within the S1 DRG (8 ± 1.7), while S2 ganglion contained the smallest number of the neurons (3.6 ± 1). In the L7 DRG, the average number of FB+ neurons was 6.2 ± 1.6. In rabbits of MED group, the largest number of FB+ neurons was found within the S1 DRG (13.4 ± 4), while the smallest one was found within the S3 ganglion (1.4 ± 0.4). In L6, L7, S2 and S4 ganglia, the number of retrogradely labelled neurons amounted to 1.6 ± 0.5, 4 ± 1.5, 4.4 ± 1.5 and 2.8 ± 1.7, respectively. The data obtained can be very useful for further investigations regarding the efficacy of denervation in the therapy of hip joint disorders in rabbits.

Characterisation and classification of the neural anatomy in the human hip joint

Hip arthroscopy remains a useful surgical intervention for labral injuries. The literature has predominantly focused on structural and vascular considerations of the hip joint, with few studies examining the neurohistology of the surrounding periarticular tissues. We mapped and identified the periarticular neural anatomy, to identify the presence of sensory nerve fibres and mechanoreceptors within the hip joint. Eight human cadaveric hips were dissected into a total of ten specimens per hip. Histological staining was used to identify neural structures taken from the superolateral, anterior, inferior, and posterior positions of the hip joint. The frozen sections were analyzed by light microscopy to calculate relative concentrations of mean neural fibres per high power field (mnf/hpf). Neural end organs were found in the hip capsule, acetabular labrum, ligamentum teres and transverse acetabular ligament. The highest levels of mechanoreceptors were found in the superolateral aspect of the hip capsule (9.6 mnf/hpf). The labrum showed highest levels of sensory fibres (3.4 mnf/hpf) and mechanoreceptors (4.3mnf/hpf) within the anterior zone. Sensory fibres and mechanoreceptors densely populate the acetabular labrum, capsule and transverse acetabular ligament. The anterior zone of the labrum contained the highest relative concentration of sensory fibres, specifically Ruffini corpuscles.

The Rottinger approach for total hip arthroplasty: technique and review of the literature

The surgical approach utilized in total hip arthroplasty has been identified as a factor that may affect surgical outcomes. There have been many different approaches and modifications used since the procedure was popularized by Sir John Charnley. The popular approaches today can be grouped by their relationship to the trochanter (anterior or posterior), patient position, leg position for dislocation/femoral preparation, and treatment of the abductors and short external rotators. The Rottinger approach is an anterior approach which utilizes the muscle interval between the tensor fascia lata and abductor musculature. The abductor attachments are preserved and the femur is prepared in extension, adduction, and external rotation. This approach has been shown in literature to be safe with some studies showing improved outcomes both in terms of reduced complications and better function than other standard approaches.

Learning curve in tissue sparing total hip replacement: comparison between different approaches

BACKGROUND

The tissue sparing surgery (TSS) concept means not only smaller incisions but also less tissue disruption, allowing decreased blood loss and improved function. However, TSS techniques can result in more complications related to the learning curve. The aim of this study was to compare the learning curve of an experienced surgeon with different TSS approaches for total hip replacement (THR) from a clinical and surgical point of view, focussing especially on complications related to the use of different geometric stems.

MATERIALS AND METHODS

Sixty patients scheduled to be operated for a primary THR were enrolled in the study and were randomly assigned to surgery by one of three different TSS approaches: lateral with mini incision (group A), minimally invasive anterior (group B) and minimally invasive antero-lateral (group C). Results from the three TSS groups were compared with a control group of 149 patients (group D).

RESULTS

Our results reveal significantly reduced blood loss in the TSS groups compared with the control group, with no differences between the TSS groups. We found better early functional scores in the two minimally invasive groups (anterior and anterolateral), and a lower rate of complications with the antero-lateral TSS approach.

CONCLUSION

The antero-lateral TSS approach seems to be safer and less demanding than standard THR surgery, and is suitable for use with different stems.

MicroHip: A minimally invasive procedure for total hip replacement surgery A modified Smith-Petersen approach

In this article we present the surgical technique of our anterior minimally invasive approach to the hip joint. This is aligned along an interneural plane and makes the approach truly minimally invasive. This technique is performed in a lateral decubitus position on a normal operating table; there is no need for a specific orthopaedic or fracture table. As leg traction is not necessary, this enables the approach to be used routinely. Most of the instruments used for this procedure are standard instruments; only the acetabular reamers and positioners are angulated and specifically designed. The angled instruments (MI minimally invasive) are especially useful when performing hip replacement in obese patients. An excellent view of both the acetabulum and the proximal femur can be obtained through an incision of only 6-8cm, using this MI approach. The approach follows the interval between the tensor fascia lata muscle and the rectus muscle using a section of the anterior iliofemoral approach described by Smith-Petersen. No tendon or muscle is cut or detached. The joint capsule is split and left in place. The hip joint is not dislocated and we perform the osteotomy of the femoral neck in situ. To date we have performed over 500 MicroHip operations. We have not observed any nerve lesions or fractures of the trochanter. Our experience to date shows that the method we have de-veloped allows us to operate reliably on virtually any patient. Preliminary results also show that important factors like length of stay, pain, blood loss and return to work can be reduced significantly. The MicroHip technique is being used by more and more different clinics all over the world and can be applied with success after suitable training.