Subchondral Bone Of Femoral Head Research Articles

The effects of nano-hydroxyapatite/polyamide 66 scaffold on dog femoral head osteonecrosis model: a preclinical study

The lack of mechanical support in the bone tunnel formed after CD often results in a poor therapeutic effect in ONFH. The n-HA/P66 has excellent biocompatibility and mechanical properties and has been widely used in bone regeneration. The present study aimed to evaluate the effects of n-HA/P66 scaffold treatment in a dog model of ONFH. A FEA was performed to analyze the mechanical changes in the femoral head after CD and n-HA/P66 scaffold or tantalum rod implantation. Fifteen male beagles were selected to establish the model of ONFH by liquid nitrogen freezing method, and the models were identified by x-ray and MRI 4 weeks after modeling and randomly divided into three groups. Nine weeks later, femoral head samples were taken for morphology, micro-CT, and histological examination. The FEA showed that the n-HA/P66 scaffold proved the structural support in the bone tunnel, similar to the tantalum rod. The morphology showed that the femoral head with n-HA/P66 implantation is intact, while the femoral heads in the model group and CD group are collapsing. Moreover, the micro-CT results of the n-HA/P66 scaffold group were better than the model group and the CD group, and the interface between the n-HA/P66 scaffold and bone tissue is blurred. Furthermore, the histological result also verifies the alterations in micro-CT, and bone tissue grows in the bone tunnel with n-HA/P66 scaffold implanted while few in the CD group. The CD results in a lack of mechanical support in the femoral head subchondral bone and bone tunnel high stress. The n-HA/P66 scaffold implantation can provide mechanical support and relieve high stress induced by CD. The n-HA/P66 scaffold can treat femoral head necrosis and provide the bone tissue growth scaffold for the femoral head after CD to promote bone tissue regeneration.

Avascular Necrosis of Femoral Head: A Retrospective Study of MRI Scan in A Orthopedic Hospital

Background : Avascular necrosis (AVN), also known as osteonecrosis of femoral head is a pathology in which many etiologies play role and cause decreased vascular supply to subchondral bone of femoral head which results in osteocyte death. MRI is the most sensitive modality for detection of AVN and is helpful for screening and detecting at early stage. Purpose: The aim of the study was to determine the prevalence pattern and stages of presentation of Avascular Necrosis (AVN) of the femoral head. Materials and Methods: This was a retrospective study carried out at the department of Radiology & Imaging, National Institute of Traumatology & Orthopedic Rehabilitation (NITOR), Dhaka where MRI of the hip joint was performed during our study period, only those patients which showed positive signs for avascular necrosis of femoral head were included and were analysed over a period of five years. The age, sex, laterally distribution, causative factors, staging according to Ficat and Arlet classification was done. Results: It was found that most commonly males of productive age group (21 to 40 years) were affected. Though most of them had unilateral involvement however number of bilateral cases were also significant. Mostly, patient presented with stage-IV disease accounting for 104 out of 152 patients (68.42%). Conclusion: Considering that the young males were commonly affected and presented with advanced stage disease at the time of diagnosis, it was recommended that screening MRI should be done in all patients presenting with hip complaints. Sir Salimullah Med Coll J 2022; 30: 180-185

Subchondral involvement in osteonecrosis of the femoral head: insight on local composition, microstructure and vascularization

To determine changes of subchondral bone composition, micro-structure, bone marrow adiposity and micro-vascular perfusion in end-stage osteonecrosis of the femoral head (ONFH) compared to osteoarthritis (OA) using a combined in vivo and ex vivo approach. Male patients up to 70 years old referred for total hip replacement surgery for end-stage ONFH were included (n=14). Fifteen patients with OA were controls. Pre-operative MRI was used to assess bone perfusion (dynamic contrast-enhanced (DCE) sequences) and marrow fat content (chemical shift imaging). Three distinct zones of femoral head subchondral bone - necrotic, sclerotic, distant - were compared between groups. After surgery, plugs were sampled in these zones and Raman spectroscopy was applied to characterize bone mineral and organic components (old and newly-formed), and contrast-enhanced micro-computed tomography (CE-μCT) to determine bone micro-structural parameters and volume of bone marrow adipocytes, using conventional 2D histology as a reference. In the necrotic zone of ONFH patients compared to OA patients: 1) the subchondral plate did not exhibit significant changes in composition nor structure; 2) the volume fraction of subchondral trabecular bone was significantly lower; 3) type-B carbonate substitution was less pronounced, 4) collagen maturity was more pronounced; and 5) bone marrow adipocytes were significantly depleted. The sclerotic zone from the ONFH group showed greater trabecular thickness, and higher DCE-MRI AUC and Ktrans. Volume fraction of subchondral bone, trabecular number, and Kep were significantly lower in the distant zone of the ONFH group. This study demonstrated alterations of subchondral bone microstructure, composition, perfusion and/or adipose content in all zones of the femoral head.

Assessment of luteinizing hormone receptor expression in structural support tissues of canine hip and femorotibial joints.

To determine whether luteinizing hormone receptors (LHRs) are expressed in canine femoral head subchondral bone (FHSB), hip joint round ligament (RL), cranial cruciate ligament (CCL), and femorotibial joint synovium (FJS) specimens. 1 specimen each of the FHSB, RL, CCL, and FJS obtained from the left hind limbs of 19 fresh canine cadavers. 1 section of each FHSB, RL, CCL, and FJS specimen was processed with rabbit polyclonal IgG anti-human LHR antibody, and 1 section was treated with negative control reagents. Percentage immunoexpression of LHRs in FHSB and FJS sections was analyzed by assessment of 100 bone marrow cells or synoviocytes in 3 adjacent hpf (400×). In each RL and CCL section, immunoexpression of LHRs in fibrocytes was semiquantitatively analyzed on the basis of the mean of the product of percentage staining score (from 0 [no staining] to 3 [> 50% of cells stained]) and staining intensity score (from 0 [no staining] to 2 [moderate to strong staining]) for 3 adjacent hpf. All tissues examined had variable LHR expression. Expression of LHRs in FHSB, CCL, or FJS specimens did not differ between sexes or between sexually intact and gonadectomized dogs. However, RL specimens from female dogs had significantly greater LHR expression scores, compared with findings for male dogs. Results indicated that LHRs are expressed in structural support tissues of canine hip and femorotibial joints. Further research is required to determine the LHRs' function, mechanism of action, and potential contribution to the pathogenesis of hip dysplasia or CCL rupture in dogs.

Assessment of the zonal variation of perfusion parameters in the femoral head: a 3-T dynamic contrast-enhanced MRI pilot study.

The objective was to describe MR perfusion characteristics of the femoral head, with a focus on the subchondral bone. This prospective monocentric study was approved by our local Ethics Committee. Written informed consent was obtained from all subjects. Dynamic contrast-enhanced MRI of the right hip was performed in 59 adults with suspected spondyloarthritis (32 women, 28 men). Mean age was 37.5 (±12.5) years. Regions of interest were drawn in the femoral head epiphysis, in the subchondral areas the most exposed to mechanical load (superolateral, anterosuperior, and posterior zones) and in areas less exposed to mechanical load (inferior subchondral zone and center of the femoral head). Semi-quantitative and pharmacokinetic parameters were calculated using the Tofts model. Statistical analysis was performed with a linear mixed model to compare the perfusion parameters in the different femoral head zones. Extravascular extracellular volume and area under the curve were lower in the superolateral zone than in the inferior zone (p=0.0135 and p<0.0001 respectively) and the central zone (p=0.007 and p=0.0134 respectively). Extravascular extracellular volume and rate constant were lower in the anterosuperior zone than in the inferior zones (p=0.011 and p=0.029). In the anterosuperior zone, extravascular extracellular volume was lower, and time to peak was higher than in the central zones (p=0.0056 and p=0.0013 respectively). No significant differences were found for any values between other paired zones. The perfusion of femoral head subchondral bone assessed with dynamic contrast-enhanced magnetic resonance imaging is not homogeneous: the areas exposed to more mechanical loading are less perfused.

Biomechanical changes in the osteonecrosis of the femoral head of rabbits treated by neuropeptide gene-transfected stem cells combined with autologous bone grafting

Objective To investigate the biomechanical changes in the osteonecrosis of the femoral head (ONFH) of rabbits treated by neuropeptide gene (calcitonin gene-related peptide α, hCGRPα)-transfected stem cells combined with autologous bone grafting. Methods The ONFH models on one side in rabbits were established by liquid nitrogen. Forty-eight rabbits ONFH models were randomly divided into 3 groups: group A [hCGRPα-transfected bone marrow mesenchymal stem cell (BMSCs) group], the hCGRPα was transfected into BMSCs combined with autologous bone graft into the femoral head; group B (BMSCs group), BMSCs were transfected with empty plasmid (only pLNCX2 plasmid) combined with autologous bone graft; group C (irrelated sequence group), BMSCs were transfected with irrelated gene combined with autologous bone graft. Animals were sacrificed at 3rd and 6th month respectively to observe the biomechanical changes in the femoral head of rabbits. Results At 3rd month after surgical treatment, in groups A, B, and C the maximum compressive strength and mean elastic modulus of the subchondral bone of femoral head on surgically treated side respectively were (29.13±1.95) and (59.61±2.18), (24.63±1.35) and (48.87±2.15), (25.05±1.34) and (50.13±2.28) mPa, and those of the cancellous bone of femoral head on surgically treated side respectively were (16.41±1.13) and (24.11±2.32), (11.43±1.55) and (17.63±2.45), (12.51±1.85) and (18.22±2.32) mPa. The biomechanical strength was the best in the femoral head in group A, which was nearly close to that in the normal side (P>0.05) and was significantly greater than that in both group B and group C (P 0.05). Conclusion hCGRPα-transfected BMSCs combined with autologous bone grafting into the femoral head of ONFH animal model can accelerate osteogenesis, enhance bone tissue repair, and then effectively recover the normal biomechanical properties of the femoral head. Key words: Calcitonin gene-related peptide; Bone marrow mesenchymal stem cells; Bone grafting; Osteonecrosis of the femoral head; Biomechanics; Rabbit

English

We describe a method of internal fixation for femoral neck fractures which has been newly developed to reduce the frequency of complications like back out, hip joint protrusion and implant failure of cannulated hip screws. Two variable length sliding compression screws are inserted in the axis of femoral neck to reach into the subchondral bone of femoral head. The screws are inserted over guide pins and the tip of screws are self-tapping and these are designed in such a way that the inner screw slides into the outer barrel to manage the collapse of bone at fracture site. The present study is of 15 cases and these cases were followed for 18 months. All fractures in union cases healed within 6 months. There was no case of late segmental collapse non-union. Functional evaluation was done on the basis of Harris hip score (HHS), according to which 8 cases had excellent, 4 cases had good and 3 cases had poor results due to avascular necrosis and non-union.

Femoral Head Stress Fracture: An Unknown Complication Following Sugioka’s Transtrochanteric Rotational Osteotomy

Sugioka's transtrochanteric rotational osteotomy, as a treatment of osteonecrosis of the femoral head, has variable success rates. Its known complications include: progressive varus deformity, femoral neck fracture, and femoral head collapse. However, femoral head stress fracture has not been described as a complication of Sugioka's transtrochanteric rotational osteotomy. This article presents cases of 2 of 64 patients who underwent Sugioka's transtrochanteric rotational osteotomy between 1994 and 2006 and experienced femoral head stress fractures. Both patients were young and active. They presented with acute inability to bear weight and pain on the operated hip after mountain climbing 1 and a half to 3 years following the index surgery. Diagnosis of femoral head stress fracture was established by the presence of an inferolaterally-directed vertical fracture line from the superolateral aspect of the femoral head on computed tomography scans for both patients. One patient was successfully managed with conservative measures, whereas the other underwent total hip replacement after failed conservative treatment. We hypothesize that the direction alteration of the trabecular system due to proximal femoral segment rotation, varus positioning of the proximal femur, and inadequate placement of the screw into the necrotic femoral head may have caused the femoral head stress fractures after transtrochanteric rotational osteotomies. Stress fracture of the femoral head is a potential complication following Sugioka's transtrochanteric rotational osteotomy for osteonecrosis of the femoral head, which may be prevented by avoiding heavy exercises such as mountain climbing, until adequate remodeling of the trabecular system is gained and screws can be inserted into the femoral head subchondral bone as deeply as possible with avoidance of the necrotic area.

Preliminary study of image findings of femoroacetabular impingement

Objective To assess the image findings of femoroacetabular impingement (FAI).Methods Image findings of 9 patients with surgically proved femoroacetabular impingement were retrospectively reviewed for characteristic image findings of FAL All 9 patients underwent X-ray examinations and MRI of affected hip, and 1 patient underwent MR arthrography (MRA) additionally. Results X-ray examinations of all 9 patients showed bump at femoral head-neck junction or overcoverage of the acetabula.MRI showed various degrees of injury of anterosuperior labrum in all 9 patients. The injuries were stage Ⅰ A in2 cases, stage Ⅰ B in3, stage ⅡA in2, and stage ⅡB in 2. MRA of the case showed tears of anterosuperior labrum, with contrast media entering into the teared labrum. There were sclerosis and cystic degeneration of subchondral bone of femoral head in 2 cases, and these findings were confirmed as cartilage delamination by surgery. Conclusions MRI can display the injures of labrum and articular cartilage, whichis helpful to the early diagnosis of FAI. Key words: Femoroacetabular impingement; Labrum; Articular cartilage; α-angle; Magnetic resonance imaging

Expression and activity of COX‐1 and 2 and 5‐LOX in joint tissues from dogs with naturally occurring coxofemoral joint osteoarthritis

Understanding the neurobiology of pain in naturally occurring models of osteoarthritis (OA) may improve the understanding of human OA pain. Both COX and LOX have been associated with joint pain. This study evaluated COX-1, COX-2, and 5-LOX expression and activity in a naturally occurring canine model of secondary OA. Hip joint capsule with synovial tissue (HJC) and femoral head subchondral bone (FH) was collected from normal dogs and dogs undergoing total hip replacement for coxofemoral joint OA. Tissues were analyzed for COX-1, COX-2, and LOX protein, and PGE(2) and LTB(4). Significantly more COX-2 protein was present in OA HJC than normal joints (p = 0.0009). There was no significant difference in COX-1 or LOX protein, although LOX protein was increased (p = 0.069). PGE(2) concentration in normal and OA HJC was similar (p = 1.0). LTB(4) concentration in OA HJC was significantly greater than normal HJC (p = 0.028). Significantly more COX-1 (p = 0.0098), COX-2 (p = 0.0028), and LOX (p = 0.0095) protein was present in OA FH tissue compared to normal FH tissue. There were no differences in PGE(2) or LTB(4) concentration in normal and OA FH tissue (p = 0.77 and p = 0.11). Together, these data suggest both COX-2 and 5-LOX are appropriate targets for the management of pain associated with naturally occurring OA.

The effect of long-term methylprednisolone treatment on the femoral head in growing pigs

The effect of long term steroid treatment on coagulation, intraosseous pressure (IOP), femoral head (FH) blood flow, and histology in the normal organism was investigated in this study in growing pigs. From 24 growing female Danish Landrace pigs from 12 litters, 12 animals daily received 100 mg methylprednisolone orally for three months. Their 12 sister pigs served as controls without steroid treatment. Prothrombin time, activated partial thromboplastin time (aPTT), fibrinogen, and antithrombin III levels were recorded in jugular venous blood. Blood flow of the hip regions was measured by means of the radioactive microsphere technique. Metaphyseal and epiphyseal IOP of the left or right proximal femur were measured. Histomorphometry of the left or right FH epiphysis was performed. Major growth inhibition was found in the corticosteroid (CS) treated group. In CS pigs, aPTT was shortened to 50% compared to control pigs. Plasma fibrinogen was higher in the CS animals. Total FH blood flow was not different while regional blood flow in the cranial subregion of the FH epiphysis was higher in the CS group. Metaphyseal and epiphyseal IOP of the proximal femur were not different in the CS animals. Histomorphometrically, cancellous bone volume (23±1% vs. 34±2%; p<0.001) and bone turnover (10±2% vs. 55±8%; p<0.001) of the FH epiphysis was lower in the CS than in the control group. The FH epiphysis of the CS animals invariably showed an irregular cartilage–bone interface with cartilaginous projections into the subchondral bone mainly in its cranial part. In normal growing pigs, long term high dose CS treatment has induced a hypercoagulable state of plasma via the intrinsic pathway of coagulation, cartilaginous projections into FH subchondral bone, FH osteopenia, and reduced bone turnover. Long-term steroid treatment did not produce FH necrosis or FH IOP alterations in the immature pig model.