The surgical anatomy of the blood supply to the femoral head: description of the anastomosis between the medial femoral circumflex and inferior gluteal arteries at the hip

Optimal entry point for antegrade and retrograde femoral intramedullary nails

Surgical management of femoral shaft fractures with intramedullary nails has become the standard of care, with multiple options for entry point described, including piriformis entry, trochanter entry and retrograde femoral nails. Our present review describes the surgical anatomy of the proximal and distal femur and its relation to different entry points for intramedullary femoral nails. In addition, we reviewed relative indications for each technique, difficulties associated and possible complications.

Deep Gluteal Pain Syndrome: Endoscopic Technique and Medium-Term Functional Outcomes

BACKGROUND

Sciatic nerve entrapment is an entity that generates disabling pain, mainly when the patient is sitting on the involved side. According to some studies, the presence of fibrovascular bands has been described as the main cause of this pathology, and the sciatic nerve's decompression by endoscopic release has been described as an effective treatment generally associated with a piriformis tenotomy. The aim of this study was to present the medium-term functional results of endoscopic release of the sciatic nerve without resection of the piriformis tendon.

METHODS

This prospective, observational study included 57 patients who underwent an endoscopic operation for sciatic nerve entrapment between January 2014 and January 2019. In all cases, a detailed medical history was obtained and a physical examination and a functional evaluation were performed using the modified Harris hip score (mHHS), the 12-item International Hip Outcome Tool (iHOT-12), and the visual analog scale (VAS) for pain. All patients had pelvic radiographs and magnetic resonance imaging (MRI) scans of the hip on the involved side and underwent a prior evaluation by a spine surgeon.

RESULTS

This study included 20 male and 37 female patients with a mean age of 43.6 years (range, 24 to 88 years) and a mean follow-up of 22.7 months. The median mHHS improved from 59 to 85 points. The median iHOT-12 improved from 60 to 85 points. The median VAS decreased from 7 to 2. Postoperative complications occurred in 12% of patients: 1 patient with extensive symptomatic hematoma, 3 patients with hypoesthesia, and 3 patients with dysesthesia.

CONCLUSIONS

Endoscopic release of the sciatic nerve by resection of fibrovascular bands without piriformis tenotomy is a technique with good to excellent functional results comparable with those of techniques in the literature incorporating piriformis tenotomy.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Endovascular Management of Iatrogenic Arterial Injuries after Orthopedic Surgery of the Lower Limb

PURPOSE

To evaluate the safety and effectiveness of embolization, and to identify the contributory factors of failures in patients treated for iatrogenic arterial injuries after orthopedic surgery of the lower limb.

MATERIALS AND METHODS

In this retrospective study, data from patients treated from December 2008 to March 2022 for an arterial injury due to orthopedic surgery of the lower limb were analyzed from a single center. Demographic, clinical, and procedure-related data were collected. Perioperative and 30-day mortalities were estimated. Odds ratios and hazard ratios were calculated for several potential risk factors: age of >75 years, atherosclerosis, preexisting infection, urgency of surgery (trauma vs elective), previous surgery, multiple distant injuries, and multiple vascular supplies to the same injury.

RESULTS

Eighty-six procedures performed on 78 patients were included in the study. The rates of technical and clinical success were 100% and 92.3%, respectively. Six (7.7%) patients were retreated because of persistent bleeding. The perioperative mortality was 1.3%, and the 30-day mortality rate was 7.7%. The presence of multiple arterial supplies, multiple injuries, previous surgery, presence of atherosclerosis, or a preexisting musculoskeletal infection resulted in a higher risk of retreatment.

CONCLUSIONS

Embolization is safe and effective in the management of iatrogenic arterial injuries after orthopedic surgery. The number of involved vascular territories was the most critical factor in determining technical failure.

Effect of ligating dogs' arteries and veins on femoral heads

Background

We separately ligated the arteries and veins of dogs to establish a canine femoral head necrosis model, then compared the differences between the outcomes of the two ligation methods on canine femoral heads.

Methods

Twenty-four dogs in this experiment were randomly and evenly sorted into two groups (Group A, the arterial group; and Group B, the venous group). In dogs in Group A, the unilateral deep femoral arteries of the hips were ligated. In dogs in Group B, the unilateral deep femoral veins of the hips were ligated. Two dogs from each group were randomly selected at the 2nd, 4th, 6th, 8th, 10th, and 12th weeks postoperatively and were marked as Groups A₁–A₆ and B₁–B₆ according to the selection times. The dogs underwent X-ray (DR) and a magnetic resonance imaging (MRI) plain scan (1.5 T) on both hip joints and were then sacrificed. Bilateral femoral head specimens were soaked in formalin and then decalcified. Hematoxylin–eosin (HE) staining and histopathologic evaluation were performed on the tissue sections.

Results

In dogs in Group B, abnormal pathologic changes, such as adipocytes fusing into cysts, were observed at the 4th week after establishing the model. MRI scans showed abnormal signal intensity at the 6th week, and fibrocyte regrowth was demonstrated in the necrotic area of the femoral heads at the 10th week. At the same time, indicators of tissue repair and fresh granulation tissue emerged. Changes in dogs in Group A, such as interstitial haemorrhage and oedema, were not noted in pathologic sections until 6 weeks after the model was established. MRI showed abnormal signals, such as a linear low signal intensity in the weight-bearing area of the femoral heads at the 8th week. New blood vessels emerged in the necrotic area at the 12th week, while there was no proliferation of fibrocytes and tissues.

Conclusions

The development and evolution of femoral head necrosis caused by ligation of the main veins of the femoral head in dogs appeared earlier than in dogs with arterial ligation, and pathologic changes, such as necrosis and repair, were more significant in dogs in the venous group than in dogs in the other group.

Hip Arthroscopy and Core Decompression for Avascular Necrosis of the Femoral Head Using a Specific Aiming Guide: A Step-by-Step Surgical Technique

Avascular necrosis of the femoral (AVN) head is a disabling disease that affects function, mobility, and quality of life in the young adult. Its pathology involves blood circulation disruption of the femoral head and subchondral infarction. This leads to cartilage thinning, femoral head depression, and cartilage breakage, which results in hip osteoarthritis. In the past decade the prevalence of intraarticular pathology has been almost 95%, this revealed with hip arthroscopy (HA). HA and core decompression (CD) of the femoral head can be used effectively and concomitantly to treat AVN with excellent results, HA allows for excellent visualization of the hip joint cartilage, allowing treatment of femoroacetabular impingement syndrome (FAIS) and intra-articular pathology. Our technique demonstrates that retrograde core decompression with allograft and mixed bone matrix is an excellent choice of treatment in the early stages of AVN/ONFH. The femoral head-specific aiming guide is very reliable, is simple to use arthroscopically if placed in the posterolateral portal of the hip, and offers exact pin placement at the necrotic site, as well as less operative time and less radiation to the patient and surgical team.

Using Fracture Patterns and Planned Operative Modality to Identify Fractured Neck of Femur Patients at High Risk of Blood Transfusion

Background Fractured neck of femurs is common, serious injuries usually requiring operative management. Red blood cell transfusions are often required to treat perioperative anaemia, but these are not without adverse effects. Aims and objectives The aim of this study is to identify subgroups of fractured neck of femur patients more likely to require red blood cell transfusions. We try to identify targeted strategies to reduce blood transfusion-associated adverse effects and thus improve outcomes. Design and methods A retrospective cohort study of 324 patients. Patients were divided into cohorts based on radiological fracture patterns and operations performed. Data were collected from patient records, picture archiving and communication systems, the local transfusion laboratory, and the national hip fracture database. The primary outcome was blood transfusion rates in different fracture patterns in fractured necks of femur patients. The secondary outcome was blood transfusion rates in different operation types for fractured neck of femur patients. Chi-squared tests for independence were performed. Results 14.9%, 34.7% and 33.3% of patients with intracapsular, intertrochanteric and subtrochanteric fractures, respectively, received blood transfusions. There was a significant relationship between fracture pattern and blood transfusion (X 2 (2, N = 324) = 17.1687, p = 0.000187). 47% of patients receiving long intramedullary nails, 45% of short intramedullary nails, 27% of open reduction internal fixations, 18% of hemiarthroplasties and 9% of total hip arthroplasties resulted in blood transfusions. There was a significant relationship between operative modality and blood transfusion (X 2 (4, N = 302) = 22.0184, p = 0.000199). Conclusion In patients who have sustained a fractured neck of the femur, the fracture pattern and operative modality are both independently associated with the rates of red blood cell transfusion. In these identified groups, we propose that increased vigilance and awareness regarding transfusion avoiding strategies are utilised with the goal of improving patient outcomes.

The effect of calcar femoral neck plating on vascularity of the femoral head and neck

Aims

Surgical treatment of young femoral neck fractures often requires an open approach to achieve an anatomical reduction. The application of a calcar plate has recently been described to aid in femoral neck fracture reduction and to augment fixation. However, application of a plate may potentially compromise the regional vascularity of the femoral head and neck. The purpose of this study was to investigate the effect of calcar femoral neck plating on the vascularity of the femoral head and neck.

Methods

A Hueter approach and capsulotomy were performed bilaterally in six cadaveric hips. In the experimental group, a one-third tubular plate was secured to the inferomedial femoral neck at 6:00 on the clockface. The contralateral hip served as a control with surgical approach and capsulotomy without fixation. Pre- and post-contrast MRI was then performed to quantify signal intensity in the femoral head and neck. Qualitative assessment of the terminal arterial branches to the femoral head, specifically the inferior retinacular artery (IRA), was also performed.

Results

Quantitative MRI revealed a mean reduction of 1.8% (SD 3.1%) of arterial contribution in the femoral head and a mean reduction of 7.1% (SD 10.6%) in the femoral neck in the plating group compared to non-plated controls. Based on femoral head quadrant analysis, the largest mean decrease in arterial contribution was in the inferomedial quadrant (4.0%, SD 6.6%). No significant differences were found between control and experimental hips for any femoral neck or femoral head regions. The inferior retinaculum of Weitbrecht (containing the IRA) was directly visualized in six of 12 specimens. Qualitative MRI assessment confirmed IRA integrity in all specimens.

Conclusion

Calcar femoral neck plating at the 6:00 position on the clockface resulted in minimal decrease in femoral head and neck vascularity, and therefore it may be considered as an adjunct to laterally-based fixation for reduction and fixation of femoral neck fractures, especially in younger patients.

Cite this article: Bone Jt Open 2021;2(8):611–617.

Hip fractures in the young polytrauma patient: a review and the latest data from the UK

Managing a hip fracture in a young adult patient in the setting of polytrauma is a particularly challenging prospect. In the UK between 2018 and 2020, 11,969 patients were recorded in the Trauma Audit and Research Network as a patient with polytrauma. Of these patients, 611 (5.1%) had a hip fracture. In this article, we discuss the initial assessment and management of these patients and common problems that are encountered and how the evidence available can help guide management.

Hip arthroscopy for lateral cam morphology: how important are the vessels?

The purpose of this narrative review is to identify the anatomy and relevant blood supply to the femoral head as it pertains to hip arthroscopy and lateral cam morphology. The primary blood supply to the femoral head is the lateral ascending superior retinacular vessels, which are terminal branches of the medial femoral circumflex artery. These vessels penetrate the femoral head at the posterolateral head–neck junction. Surgeons performing posterolateral femoral osteoplasty must respect this vasculature to avoid iatrogenic avascular necrosis (AVN). Avoidance of excessive traction, avoidance of distal posterolateral capsulotomy and avoidance of disruption of the superior retinacular vessels should keep the risk for AVN low. Hip extension, internal rotation and distraction are useful in hip arthroscopy to better visualize lateral/posterolateral cam morphology to facilitate an accurate comprehensive cam correction and avoid vascular disruption.

The short external rotators dissection during the posterior approach in total hip arthroplasty did not change the blood flow

OBJECTIVES

The posterior approach in total hip arthroplasty (THA) often requires dissection of the short external rotators (SERs), which could increase the postoperative dislocation rate. The reattachment of the dissected SERs has been reported to reduce the dislocation rate, while such repair generally causes progression of muscle atrophy. 1 of the suggested causes of atrophy is reduced blood flow to the repaired SERs. The present study aimed to measure the blood flow of the SERs before dissection (pre-tenotomy) and after reattachment (post-reattachment) during the posterior approach in THA.

METHODS

This prospective study included 26 patients who underwent THA via the posterior approach. A laser-Doppler rheometer was used to measure the blood flow in the following SERs at the time of pre-tenotomy and post-reattachment: the piriformis muscle (PM), superior gemellus (SG), inferior gemellus (IG), obturator internus (OI), and subcutaneous tissue as a control.

RESULTS

The average pre-tenotomy and post-reattachment blood flows (mL/minutes/100 g) were: 1.90 ± 0.28 and 1.92 ± 0.40 in the PM, 1.94 ± 0.20 and 1.99 ± 0.39 in the SG, 1.91 ± 0.21 and 1.94 ± 0.30 in the IG, 1.93 ± 0.22 and 1.98 ± 0.36 in the OI, and 1.94 ± 0.24 and 1.87 ± 0.38 in the subcutaneous tissue. The pre-tenotomy and post-reattachment blood flows did not show significant difference in any muscle.

CONCLUSIONS

Laser-Doppler blood flow measurements showed that the blood flow is preserved, even when the SERs are dissected and reattached in THA via the posterior approach.

Femoral neck osteotomy in skeletally mature patients: surgical technique and midterm results

PURPOSE

Using an extended retinacular flap containing the blood supply for the femoral head, proximal femur osteotomies can be performed at the neck level increasing the potential of correction of complex morphologies. The aim of this study was to analyze the safety, clinical, and radiographic results of this intra-articular surgical technique performed in skeletally mature patients with a minimum follow-up of three years.

METHODS

Fourteen symptomatic adult patients (16 hips) with a mean age of 26 years underwent FNO using surgical hip dislocation and an extended soft tissue flap. Radiographs and radial magnetic resonance imaging (MRI) were obtained before and after surgery to evaluate articular congruency, cartilage damage, and morphologic parameters. Clinical functional evaluation was done using the Nonarthritic Hip Score (NAHS), the Hip Outcome Score (HOS), and the modified Harris Hip Score (mHHS).

RESULTS

After surgery, no avascular necrosis was observed, and all the osteotomies healed without complication. The initial neck/shaft angle (range 120 to 150°) improved in all cases to a mean value of 130° ± 4.6 (p < 0.001). In eight of nine valgus hips, the high-positioned fovea capitis changed to a normal position after surgery. The NAHS score improved from a mean of 36.5 ± 14.9 to 82.9 ± 13.9 points after surgery (p < 0.001). After surgery, the mean HOS was 87.1 ± 17.6 points, and the mean mHHS was 78.6 ± 17 points.

CONCLUSIONS

In this series, femoral neck osteotomy in the adult, although technically more demanding compared with other classic osteotomies, can be considered a safe procedure with considerable potential to correct hip deformities.

Detection of vascularity of femoral head using sub-millimeter resolution steady-state magnetic resonance angiography-initial experience

OBJECTIVE

The purpose of this study was to use the steady-state (SS) magnetic resonance angiography (MRA) with a sub-millimeter resolution to detect the arteries supplying to the femoral head (FH).

MATERIALS AND METHOD

SS MRA scanning of hips was performed bilaterally in 15 healthy volunteers. A blood pool contrast agent was used. The scanning protocol included a 0.8-mm³ isotropic T1-fast field echo sequence with spectral fat suppression technique. Two highly qualified radiologists independently evaluated the medial circumflex femoral artery (MCFA), the lateral circumflex femoral artery (LCFA), and the three retinacular arteries including superior retinacular artery (SRA), inferior retinacular artery (IRA), and anterior retinacular artery (ARA). The intraosseous branches of the three retinacular arteries were also evaluated. An orthopaedic surgeon was consulted in case of disagreement. Observation by the two radiologists and support from the orthopaedic surgeon served as the end result. Agreement between the two observer radiologists was evaluated.

RESULTS

Interobserver agreement between the two radiologists was found to be substantial to perfect. Of the 30 hips, the LCFA and MCFA were detected in all hips; the SRA and IRA were detected in most hips (100%, 90%), and the ARA was detected in 13 hips (43%). The intraosseous branches of SRA and IRA were detected in 30 and 22 hips (100%, 73%), respectively, while the intraosseous branches of ARA were detected in 11 hips (37%).

CONCLUSION

The main arteries supplying the FH can be detected by the SS MRA, making it a novel method to detect the vascularity of FH.

Femoral Head Vascularity: Implications Following Trauma and Surgery About the Hip

Traumatic injury and surgical intervention about the hip joint place the arterial supply to the femoral head (FH) at risk. Compromised perfusion may lead to FH ischemia, cell death, and osteonecrosis. Progression to FH collapse may lead to pain, functional impairment, and decreased quality of life, especially in younger patients. This review describes the arterial supply to the FH, analyzes the impact of femoral neck fractures on FH vascularity, and explores the vascular implications of various surgical interventions about the hip, offering specific techniques to minimize iatrogenic damage to the vessels supplying the FH. [Orthopedics. 2019; 42(5):250-257.].

Evaluating the Blood Supply of the Femoral Head During Different Stages of Necrosis Using Digital Subtraction Angiography

The authors investigated changes in the blood supply of necrotic femoral heads using digital subtraction angiography (DSA). Digital subtraction angiography was used to evaluate the blood perfusion of osteonecrosis of the femoral head of 81 patients (81 hips). Necrotic hips were grouped according to the Association Research Circulation Osseous staging classification. Five parameters were assessed to evaluate the intraosseous blood supply of the necrotic femoral heads. The authors chose the most effective images retrospectively and measured the following parameters: the blood vessel diameter ratio between the medial circumflex femoral artery (MCFA) and the deep femoral artery (DFA) (MCFA/DFA); the blood vessel diameter ratio between the lateral circumflex femoral artery (LCFA) and the DFA (LCFA/DFA); the ratio between the MCFA extending length and the width of the femoral neck (A); the number of vessels that reach or exceed line I (a, horizontal line through the junction of the upper femoral head and neck); and the number of vessels that reach or exceed line II (b, the boundary between the femoral head and neck). Significantly negative correlation with Association Research Circulation Osseous stage II to IV necrosis was found for A, a, and b. These parameters were significant (P<.05). Compared with the length and distribution of the vessels, differences in width (MCFA/DFA and LCFA/DFA) were not statistically significant in patients with Association Research Circulation Osseous stage II to IV necrosis. The relative length of the MCFA and the number of vessels above line I and line II are related to the severity of osteonecrosis of the femoral head, as revealed by DSA. Evaluation of blood supply by DSA can be used as one element to predict the fate of precollapsed femoral head. [Orthopedics. 2019; 42(2):e210-e215.].

Vascular Anatomy of the Medial Femoral Neck and Implications for Surface Plate Fixation

OBJECTIVES

To describe the inferior retinacular artery (IRA) as encountered from an anterior approach, to define its intraarticular position, and to define a safe zone for buttress plate fixation of femoral neck fractures.

METHODS

Thirty hips (15 fresh cadavers) were dissected through an anterior (Modified Smith-Petersen) approach after common femoral artery injection (India ink, blue latex). The origin of the IRA from the medial femoral circumflex artery and the course to its terminus were dissected. The IRA position relative to the femoral neck was described using a clock-face system: 12:00 cephalad, 3:00 anterior, 6:00 caudad, and 9:00 posterior.

RESULTS

The IRA originated from the medial femoral circumflex artery and traveled within the Weitbrecht ligament in all hips. The IRA positions were 7:00 (n = 13), 7:30 (n = 15), and 8:00 (n = 2). The IRA was 0:30 anterior to (n = 24) or at the same clock-face position (n = 6) as the lesser trochanter. The mean intraarticular length was 20.4 mm (range 11-65, SD 9.1), and the mean extraarticular length was 20.5 mm (range 12-31, SD 5.1).

CONCLUSIONS

The intraarticular course of the IRA lies within the Weitbrecht ligament between the femoral neck clock-face positions of 7:00 and 8:00. A medial buttress plate positioned at 6:00 along the femoral neck is anterior to the location of the IRA and does not endanger the blood supply of the femoral head. The improved understanding of the IRA course will facilitate preservation during intraarticular approaches to the femoral neck and head.

Osteonecrosis of the Femoral Head: Etiology, Investigations, and Management

Femoral head osteonecrosis is a condition caused by a compromise of the blood supply of the femoral head. The precarious blood supply of the head and its role as a major weight-bearing joint makes it one of the most common bones to be affected by osteonecrosis. We describe the etiology, clinical presentation, investigations and common management options used nowadays to treat it.

The origin of the medial femoral circumflex artery, lateral femoral circumflex artery and obturator artery

Introduction

The most significant blood vessel supplying the hip joint is the medial femoral circumflex artery (MFCA). MFCA with lateral femoral circumflex artery (LFCA) are the first branches of the deep femoral artery (DFA) or they originate directly from the common femoral artery (CFA) or superficial femoral artery (SFA).

Purpose and methods

We analyzed 100 CT angiogram of the hip region [72 men, 28 women; mean age 46.4 (14–80)] to assess the frequency of each type of division of the MFCA and LFCA from either the DFA or directly from the CFA or SFA. To assess the variations on each side in one individual we analyzed both hips in 73 patients [mean age 46.6 (14–80)].

Results

Many different types of division have been described. The most frequent one in which both the MFCA and LFCA originate from the DFA, was observed in 50% of patients. In 31% of hips the MFCA originates from the CFA. In our study, a normal origin of the obturator artery from the internal iliac artery was observed in 67% of patients and an atypical origin, called corona mortis was observed in 33% of patients.

Conclusions

The deep branch of the MFCA is the main artery supplying the femoral head, it is at risk during surgical approach to the hip joint. The atypical anastomosis called corona mortis is also at risk while performing the approach to pubic bone. Therefore, knowledge of their topography is very important.

Neglected traumatic hip dislocation: Influence of the increased intracapsular pressure

AIM

To investigate that the increased intracapsular pressure, during the delay period, can interrupt the blood flow to the femoral head.

METHODS

An observational retrospective study included a group of 17 patients with traumatic hip dislocation, their ages at time of injury averaged 26 (range from 3 to 70) years. Outcomes were assessed clinically and radiographically at a period averaged 11.5 (range from 4 to 20) years.

RESULTS

Minor trauma caused dislocation in seven and severe trauma in ten patients. All dislocations were posterior, six isolated dislocation and 11 were associated with other injuries. The negligence period averaged 2.5 (ranged from 1 to 4) d. At the latest visit, the radiography revealed normal hip in 11 and avascular necrosis (AVN) in six patients. Clinically, eight patients were rated as excellent, three good, three fair and three poor.

CONCLUSION

We believe the factors that contribute to increased intracapsular pressure also increase the influence of delayed reduction toward the development of AVN.

Valproic acid prevents glucocorticoid‑induced osteonecrosis of the femoral head of rats

Glucocorticoids (GCs) are the most common cause of atraumatic osteonecrosis of the femoral head (ONFH) because their effect compromises the osteogenic capability of bone marrow-derived mesenchymal stem cells (BMSCs). Valproic acid (VPA) is a widely used anti-epileptic and anticonvulsant drug. Previous studies have reported that VPA promotes osteogenic differentiation of MSCs in vitro and osteogenesis in vivo as a histone deacetylase (HDAC) inhibitor. The purpose of the present study was to investigate the efficacy of VPA as a precautionary treatment of ONFH after GC treatment in rats. In vitro, the effect of VPA, dexamethasone or a combination treatment of the two on the proliferation and osteogenic differentiation of human BMSCs was assessed using a Cell Counting Kit-8 and apoptosis assays, and by measuring the expression of proteins associated with osteogenesis. In vivo, a GC-induced ONFH model was established in rats and VPA was added during GC treatment to investigate the preventive effect of VPA against ONFH. Rat BMSCs were also extracted to investigate the osteogenic capacity. The results of micro-computed tomography scanning, angiography of the femoral head and histological and immunohistochemical analyses indicated that 11 of 15 rats induced with methylprednisolone (MP) presented with ONFH, while only 2 of 15 rats treated with a combination of MP and VPA developed ONFH. VPA produced beneficial effects on subchondral bone trabeculae in the femoral head with significant preservation of bone volume and blood supply, as well as improved osteogenic capability of BMSCs compared with those in rats treated with GC alone. In conclusion, VPA attenuated the inhibitory effect of GC on BMSC proliferation and osteogenesis by inhibiting apoptosis and elevating the expression of proteins associated with osteogenesis, which may contribute to the prevention of GC-induced ONFH in rats.

Arterial Topographic Anatomy Near the Femoral Head-Neck Perforation with Surgical Relevance

BACKGROUND

Knowledge of the vascular supply of the femoral head is crucial for hip-preserving surgical procedures. The critical area for reshaping cam deformity is at the retinacular vessel penetration, an area with ill-defined topographic anatomy. We performed a cadaver study of the extension of the lateral retinaculum near the head-neck junction, distribution of the arterial vascular foramina, and initial intracapital course of these vessels.

METHODS

In 16 fresh proximal parts of the femur without head-neck deformities, the deep branch of the medial femoral circumflex artery was injected with gadolinium for magnetic resonance imaging (MRI) sequences to identify arterial structures.

RESULTS

We found a mean number of 4.5 arterial foramina, showing a predominance from 10 to 12 o'clock. The retinaculum extended 20 mm from 1 to 10 o'clock. The surface distance from the cartilage border to the vascular foramina under the synovial fold was 6.5 mm, and the depth from the same cartilage border to the initial intraosseous vessel pathways was 5.3 mm.

CONCLUSIONS

The data add further precision to the arterial topography at the retinacular foramina, an area that is crucial for the perfusion of the femoral head. It may overlap with the area of anterolateral cam deformity and plays a role in choosing the cuts for subcapital and intracapital osteotomies.

CLINICAL RELEVANCE

The information is taken from normal hips and may not be directly applicable to the deformed hip. Nevertheless, it is a prerequisite for a surgeon to understand the normal anatomy and use those boundaries to prevent mistakes during intra-articular joint-preserving hip surgical procedures.

What Happens to the Articular Surface After Curettage for Epiphyseal Chondroblastoma? A Report on Functional Results, Arthritis, and Arthroplasty

BACKGROUND

Chondroblastoma is an uncommon, benign, but locally aggressive bone tumor that occurs in the apophyses or epiphyses of long bones, primarily in young patients. Although some are treated with large resections, aggressive curettage and bone grafting are more commonly performed to preserve the involved joint. Such intralesional resection may result in damage to the growth plate and articular cartilage, which can result in painful arthritis. Prior studies have focused primarily on oncologic outcomes rather than long-term joint status and functional outcomes.

QUESTIONS/PURPOSES

(1) What local complications can be expected after aggressive intralesional curettage of epiphyseal chondroblastoma? (2) What is the joint survival of a joint treated in this way for chondroblastoma? (3) What additional procedures are used in treating symptomatic joint osteoarthritis after treatment of the chondroblastoma? (4) What are the functional outcomes in this group of patients?

METHODS

A retrospective study of our prospectively collected database between 1975 and 2013 was done. We found 64 patients with a diagnosis of chondroblastoma of bone. After applying our selection criteria, 53 patients were involved in this study. We excluded seven patients with tumors initially treated with en bloc resection (five located in the extremities and two in the axial skeleton) and two patients with apophyseal tumors. One patient who underwent nonsurgical treatment and one patient lost to followup were also excluded. The mean age was 18 years (range, 11-39 years); the minimum followup was 2 years with a mean followup 77 months (range, 24-213 months). We analyzed all patients with a diagnosis of epiphyseal chondroblastoma of the limb treated with aggressive curettage and joint preservation surgery. During the period in question, our general indications for curettage were patients with active, painful tumors and those with more aggressive ones that remained intracompartmental, whereas initial wide en bloc resection was indicated in patients who had tumors with an extracompartmental extension breaching the adjacent joint cartilage and massive articular destruction. The tumor location was the distal femur in 14 patients, proximal tibia in 11, proximal humerus in 10, proximal femur in eight, the talus in seven, and elsewhere in the lower extremity in three. Local complications including joint degeneration and tumor recurrence were evaluated. Based on radiographic analysis, secondary osteoarthritis was classified by using the Kellgren-Lawrence grading system from Grade 0 to Grade IV. Patients who underwent joint replacement resulting from advanced symptomatic osteoarthritis were considered to have had joint failure for purposes of survivorship analysis, which was estimated using the Kaplan-Meier method. Functional results were evaluated with the Musculoskeletal Tumor Society functional score by the treating surgeon, who transcribed the results on the digital records every 6 months of followup.

RESULTS

Twenty-two patients (42%) developed 26 local complications. The most common local complication was osteoarthritis in 20 patients (77% [20 of 26 complications]); tumor recurrence was observed in four patients; an intraarticular fracture and superficial infection treated with surgical débridement and antibiotics developed in one patient each. Joint survival was 90% at 5 years (95% confidence interval [CI], 76%-100%) and 74% at 10 years (95% CI, 48%-100%). Proximal femoral tumor location was associated with lower survivorship of the joint than other locations showing a 5-year survival rate of 44% (95% CI, 0%-88%; p = 0.000). Of the 20 patients with osteoarthritis, four were symptomatic enough to undergo joint replacement, all of which were for tumors in the proximal femur. The mean Musculoskeletal Tumor Society functional score was 28 of 30 points (93%).

CONCLUSIONS

Osteoarthritis was a frequent complication of aggressive curettage of epiphyseal chondroblastoma, and tumors located in the proximal femur appeared to be at particular risk of secondary osteoarthritis and prosthetic replacement. Because chondroblastoma is a tumor that disproportionately affects younger patients, the patient and surgeon should be aware that arthroplasty at a young age is a potential outcome for treatment of proximal femoral chondroblastomas.

LEVEL OF EVIDENCE

Level III, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Surgical hip dislocation through a direct lateral approach: A cadaveric study of vascular danger zones

OBJECTIVE

There is limited information on the potential danger to the vascularity of the femoral head during surgical dislocation of the hip using the direct lateral approach. The objective of this study was to investigate the topographical anatomy of the medial femoral circumflex artery (MFCA), the primary source of blood supply to the femoral head, in relationship to the direct lateral approach.

METHODS

Seven unembalmed cadaver hips had dye injection into either the profunda femoris artery or the MFCA. Surgical hip dislocation was then performed through a direct lateral approach, noting the danger zones to the MFCA branches during each step of the exposure.

RESULTS

None of the MFCA branches were found to cross the anterior surgical field superficial to the capsule. The deep (main) branch of the MFCA pierced the inferior capsule at the level of the lesser trochanter after emerging posterior to iliopsoas tendon. Ascending branches up the medial femoral neck were identified at this level. The deep branch then coursed posteriorly terminating in a variable number of vessels ascending the posterior femoral neck. Dislocation of the femoral head did not stretch or alter the course of the deep branch of the MFCA.

CONCLUSION

Safe surgical hip dislocation preserving the MFCA can be performed though a direct lateral approach as long as the inferomedial portion of the anterior capsule is preserved (main branch of the MFCA pierces the capsule at this level). Extracapsular injury is possible from inadvertent dissection at the level of the lesser trochanter or aggressive retraction on the iliopsoas. The posterior capsule should be left intact and instrumentation around the posterior neck should be avoided.

Rate of avascular necrosis and time to surgery in proximal humerus fractures

PURPOSE

Avascular necrosis (AVN) of the humeral head is a devastating complication of proximal humeral fracture (PHF) that often results in long-term morbidity for the patient. Rates of AVN depend on the number of fracture fragments and are highly variable. The literature suggests that timely stable and anatomic reduction may decrease the rate at which AVN develops after PHF. To our knowledge, there is no literature published investigating a temporal relationship between the timing of PHF fixation and rates of AVN.

METHODS

Operative records of one orthopedic trauma surgeon were used to identify patients that underwent open reduction internal fixation for PHF at our institution between 2007 and 2012. Radiographs at presentation were reviewed and used to classify the fractures into two, three or four parts. Date and time of the initial radiograph were recorded as were the date and time of available intra-operative fluoroscopic images. The time from presentation radiograph to operative fixation was calculated (hours). Available follow-up plain films were then reviewed and evaluated for the presence or absence of humeral head AVN.

RESULTS

Time to surgery (less than or greater than 72 h) and patient age did not correlate with development of AVN after PHF (p > 0.26). Notably, the number of fracture fragments did influence the rate of AVN identified in patients with PHF (p = 0.002).

CONCLUSION

Early operative intervention does not appear to decrease the rate of development of avascular necrosis after PHF.

Hip Vascularity: A Review of the Anatomy and Clinical Implications

Throughout development, the vascular supply to the proximal femur and acetabulum undergoes a series of changes during which it is susceptible to injury. Before age 3 months, the ligamentum teres and lateral epiphyseal arteries are the dominant supply to the developing head. The dominant supply shifts to the lateral epiphyseal vessels by age 18 months. The distinct metaphyseal and epiphyseal circulations of the adult proximal femur form in adolescence when an increasingly rich metaphyseal circulation supplies the subphyseal region, terminating at the physeal plate. The acetabular blood supply derives from two independent systems, with the dominance of each changing throughout maturity. Most descriptions of the vascular contributions to the proximal femur and acetabulum have been gross anatomic and histologic studies. Advanced imaging studies (eg, CT angiography, perfusion MRI) have added to our understanding of the vascular anatomy of the proximal femur and acetabulum, its changes throughout development, and its clinical implications.

A Vessel-Preserving Surgical Hip Dislocation Through a Modified Posterior Approach: Assessment of Femoral Head Vascularity Using Gadolinium-Enhanced MRI

BACKGROUND

Surgical hip dislocation allows circumferential access to the femoral head and acetabulum and is utilized in the treatment of intra-articular hip disorders. Surgical hip dislocation is currently performed with a trochanteric osteotomy that reliably preserves the femoral head arterial supply; however, trochanteric nonunion or painful hardware requiring removal may occur. In a cadaveric model, using gadolinium-enhanced magnetic resonance imaging (MRI) and gross dissection, we evaluated whether modifications to the posterior approach preserve the femoral head arterial supply after a posterior surgical hip dislocation.

METHODS

In eight fresh-frozen pelvic specimens, a surgical hip dislocation was performed through the posterolateral approach with modifications in the tenotomy of the short external rotators and a capsulotomy designed to preserve the medial femoral circumflex artery (MFCA). Modifications included tenotomies of the quadratus femoris, conjoined tendon of the short external rotators, and obturator externus made 2.5 cm medial to their insertion on the greater trochanter and a T-type capsulotomy originating below the cut edge of the obturator externus tendon and continuing circumferentially along the acetabular rim. After hip dislocation, the MFCA was cannulated and MRI scans were acquired before and after gadolinium enhancement for evaluation of femoral head perfusion, with the contralateral hip, which was left intact, used as a control. Anatomic gross dissection was performed after the injection of polyurethane in the MFCA and confirmed MFCA vessel integrity.

RESULTS

Quantitative MRI showed that the operatively treated hip retained a mean perfusion (and standard deviation) of 95.6% ± 9.7% in the femoral head and 94.7% ± 21.5% in the femoral head-neck junction compared with the control hip (p = 0.66 and p = 0.85, respectively). Dissection after polyurethane injection confirmed that the superior retinacular and inferior retinacular arteries entering the femoral head were intact in all specimens.

CONCLUSIONS

In a cadaveric model using gadolinium-enhanced MRI, we found that standardized modifications to the posterior approach, specifically with regard to the location of the short external rotator tenotomy and capsulotomy, successfully preserved the femoral head arterial supply after posterior surgical hip dislocation.

CLINICAL RELEVANCE

While further research is necessary before these modifications can be recommended for widespread clinical use, the results of this study suggest the extracapsular vascular anatomy can be safely preserved during posterior surgical hip dislocation.

The terminal branches of the medial femoral circumflex artery: the arterial supply of the femoral head

This study investigates and defines the topographic anatomy of the medial femoral circumflex artery (MFCA) terminal branches supplying the femoral head (FH). Gross dissection of 14 fresh-frozen cadaveric hips was undertaken to determine the extra and intracapsular course of the MFCA's terminal branches. A constant branch arising from the transverse MFCA (inferior retinacular artery; IRA) penetrates the capsule at the level of the anteroinferior neck, then courses obliquely within the fibrous prolongation of the capsule wall (inferior retinacula of Weitbrecht), elevated from the neck, to the posteroinferior femoral head-neck junction. This vessel has a mean of five (three to nine) terminal branches, of which the majority penetrate posteriorly. Branches from the ascending MFCA entered the femoral capsular attachment posteriorly, running deep to the synovium, through the neck, and terminating in two branches. The deep MFCA penetrates the posterosuperior femoral capsular. Once intracapsular, it divides into a mean of six (four to nine) terminal branches running deep to the synovium, within the superior retinacula of Weitbrecht of which 80% are posterior. Our study defines the exact anatomical location of the vessels, arising from the MFCA and supplying the FH. The IRA is in an elevated position from the femoral neck and may be protected from injury during fracture of the femoral neck. We present vascular 'danger zones' that may help avoid iatrogenic vascular injury during surgical interventions about the hip.

BLEEDING OF FEMORAL HEAD DURING TOTAL HIP ARTHROPLASTY FOR OSTEOARTHROSIS

Objective: To evaluate the bleeding of the femoral head on hip osteoarthritis in patients who underwent total hip arthroplasty. Methods: One hundred and three hips affected by primary hip osteoarthritis were evaluated. After surgical dislocation, the femoral head was divided into four quadrants, and micro perforations were made in order to observe and assess the presence of bleeding, as early type (EB), late type (LB) or without bleeding (WB). Results: We observed early bleeding (EB) in the upper quadrant in 16 hips (15.5%), late bleeding in 14 hips (13.6%) and no bleeding (WB) in 73 hips (70.9%). The anterior quadrant showed EB in 24 hips (23.3%), LB in 7 hips (6.8%) and WB in 72 hips (69.9%). The lower quadrant presented EB in 40 hips (38.8%), LB 14 hips (13.6%) and WB in 49 hips (47.6%). The posterior quadrant showed EB in 39 hips (37.9%), LB 19 hips (18.4%) and WB in 45 hips (43.7%). Comparing BMI and gender, we found no association between these parameters

(p> 0.05). Conclusions: The inferior and posterior quadrant had the highest bleeding levels, following the path of the medial circumflex artery. Level of Evidence III, Therapeutic Study.

A novel surgical approach for the treatment of tumors in the lesser trochanter

The proximal femur is a common location for the development of primary benign bone tumors. However, there is currently no surgical technique designed specifically for treating tumors located in the lesser trochanter. In the present study, a novel procedure was developed for directly exposing the lesser trochanter for surgical intervention. This technique may be particularly suited to treating tumors that extend toward the lateral and anterior forward of the lesser trochanter. The new approach involved passing through the femoral triangle, separating the femoral nerve and femoral vessels (artery and vein) and resecting the tumor between the iliopsoas and pectineal muscles. The procedure was performed on six patients with various types of tumor, including one case with osteoid osteoma, one case with non-osteogenic fibroma, one case with osteoma, one case with liposarcoma and two cases of osteochondroma. The preliminary results indicated that the surgical durations were short (60-100 min), blood loss was minimal (30-200 ml) and that pain relief was achieved following surgery. Only one patient continued to experience mild pain, scoring 18 mm on a visual analog scale. The other patients were fully relieved of pain. Sensory dysfunction was experienced by one patient following surgery, with persistent numbness and paresthesias in the distribution of the femoral nerve. No cases of deep vein thrombosis, femur head necrosis, hip joint degeneration disease or local recurrence were identified in any patients during the follow-up period. In order to clarify the virtual tissue, such vessels, nerves and the available space in our approach area, we collected 20 cadaveric specimens and performed anatomical examinations in and around the formal triangle. The spaces between the femoral artery and femoral nerve were measured and analyzed, with the results demonstrating that a definite space existed. Therefore, the novel approach presented in the study may be useful in the resection of benign tumors and the preoperative palliative resection of malignant tumors. The technique may be particularly suited to tumors extending toward the lateral and anterior of the lesser trochanter.

Surgical hip dislocation: techniques for success

Surgical hip dislocation (SHD) is a versatile approach used to address both intra-articular and extra-articular pathology around the hip joint in both pediatric and adult patients. It allows anterior dislocation of the femoral head for direct visualization of the hip joint while preserving femoral head vascularity and minimizing trauma to the abductor musculature. Previously described indications for SHD include femoroacetabular impingement, deformity resulting from Legg-Calve-Perthes disease, slipped capital femoral epiphysis, periarticular trauma, benign lesions of the hip joint, and osteochondral lesions. In this review, we will describe current surgical techniques, indications, and clinical outcomes for SHD.

Anatomical considerations in adult femoral neck fractures: how anatomy influences the treatment issues?

Femoral neck fractures in physiologically young adults are relatively uncommon. The reported incidence of avascular necrosis and nonunion rates remain relatively high despite the advancement in understanding and surgical management. Understanding the normal femoral neck anatomy and its relationship to presenting fracture pathology in young adults could help to lessen reported high complication rates to provide better clinical outcomes.

Uncommon branching pattern with a prominent articular ramus of the inferior gluteal artery in a Korean male cadaver

We found a rare case of uncommon branching pattern with a prominent articular ramus of the inferior gluteal artery in a 39-year-old Korean male cadaver, whose cause of death was rectal carcinoma. The inferior gluteal artery branches off downwards at a time, the muscular rami ran in parallel with one another, and the articular ramus gave another muscular branch and has an anastomosis with the medial circumflex femoral artery. Knowledge of vascular variations in the gluteal region may give useful information of versatile flaps for reconstruction and the prominent articular ramus found in this case is good enough to consider the existence of the anastomosis between the medial circumflex femoral artery and the inferior gluteal artery as normal, not rudimentary.

Operative treatment and avascular necrosis of the hip development disorder

PURPOSE

The purpose of this research was (1) to evaluate the consequences of an operative treatment of hip developmental disorder in children, (2) to evaluate the significance of hip vascular supply in children through indirect radiological signs, such as morphological changes on femoral head, and to classify them with standard classification methods, and (3) to analyse the research results and make a recommendation for the following treatment dilemma: when is the optimal time for an operative treatment of a hip development disorder?

METHODS

The research is a retrospective and observational analysis based on the classification of indirect radiological signs of local vascular disorder by the Bucholz-Ogden's scale. Materials used for this research are medical records of treated patients at the Clinic for Orthopaedics and Traumatology of the Sarajevo University Clinical Centre. Using a random selection, two groups of 30 patients with hip development disorder were formed. The first group was comprised of patients aged six to 18 months and the second group of patients aged 18-60 months. The medical records used for this research included all necessary anamnestic details and postoperative state treatments with clinical findings and regular radiological check-up findings that include the presence or absence of the ossification nucleus as well as its position. All patients underwent surgery with the same operative technique. Data analysis points include the state at the beginning of the treatment, the postoperative state, the state at discharge as well as control findings that followed the development of the proximal femoral part up to 72 months on average. The analysis covered data such as age, sex, family anamnestic data, clinical findings and radiological findings regarding the femoral head morphology (appearance, size, shape, position and indirect signs showing lack of vascular supply). In addition, data analysis included the types of any previous conservative or operative treatments, the duration of previous conservative treatments and repeated hospitalization.

RESULTS

In group 1, 86.6 % were female patients and 80 % in group 2. Family history was positive in 15.6 % in group 1 and 13.3 % in group 2. A total of 51.6 % of all patients started walking on time, while the rest had problems with verticalization. Of all patients, 47 % did not undergo any kind of prior treatment. Only 62.2 % of group 1 patients had ossification nucleus present, while the entire group 2 had it present. Results showed that 24.32 % of group 1 patients had none or minimal signs of avascular necrosis (AVN) while 39.47 % of group 2 had none or minimal signs of AVN; 60.52 % of group 2 patients had signs of AVN.

CONCLUSION

The results of this study show that the performance of a surgical treatment during the age between 12 and 20 months is burdened by the highest percentage of avascular necrosis. Even though AVN can be noticed in other age groups, according to the results of our research, it seems that vascular supply of the hip is the most vulnerable in the period between 12 and 20 months.

Assessment of femoral head and head-neck junction perfusion following surgical hip dislocation using gadolinium-enhanced magnetic resonance imaging: a cadaveric study

BACKGROUND

The purpose of the present study was to quantify perfusion to the femoral head and head-neck junction using gadolinium-enhanced magnetic resonance imaging following three surgical dislocations of the hip (trochanteric flip osteotomy, standard posterior approach, and modified posterior approach).

METHODS

The medial femoral circumflex artery was cannulated in fifty fresh-frozen cadaveric hips (twenty-five pelvic specimens). One hip on each pelvic specimen was randomly chosen to undergo one of the three surgical dislocations, and the contralateral hip was used as a control. Gadolinium enhancement on the magnetic resonance imaging scan was quantified in both the femoral head and head-neck junction by volumetric analysis using custom magnetic resonance imaging analysis software. A polyurethane compound was then injected, and gross dissection was performed to assess the extraosseous vasculature.

RESULTS

Magnetic resonance imaging quantification revealed that the trochanteric flip osteotomy group maintained almost full perfusion (mean, 96% for the femoral head and 98% for the head-neck junction). The standard posterior approach almost completely compromised perfusion (mean, 4% for the femoral head and 8% for the head-neck junction). Six specimens in the modified posterior approach group demonstrated partial perfusion (mean, 32% in the femoral head and 26% in the head-neck junction). Three specimens in the modified posterior approach group demonstrated almost full perfusion (mean, 96% in the femoral head and 97% in the head-neck junction). Gross dissection revealed that all specimens in the standard posterior approach group and seven of ten in the modified posterior approach group sustained disruption of the ascending branch of the medial femoral circumflex artery. All specimens in the standard posterior approach group demonstrated disruption of the inferior retinacular artery. The inferior retinacular artery remained intact in nine of ten specimens in the modified posterior approach group. One specimen in the modified posterior approach group that had disruption of both the ascending medial femoral circumflex artery and inferior retinacular artery demonstrated a substantial decrease in perfusion (7% in the femoral head and 5% in the head-neck junction).

CONCLUSIONS

The trochanteric flip osteotomy preserves the vascular supply to the femoral head and head-neck junction. The standard posterior approach disrupts the vascular supply and should be completely abandoned for surgical hip dislocation. Despite reduced enhancement, substantial perfusion of the femoral head and head-neck junction was present in the modified posterior approach group, likely because of the preservation of the inferior retinacular artery. The modified posterior approach produced variable results, indicating that improvement to the modified posterior approach is needed.

CLINICAL RELEVANCE

Our study provides previously unreported quantitative magnetic resonance imaging data on the perfusion to the femoral head and head-neck junction during common surgical approaches to the hip.

Bone vascularization in normal and disease conditions

Bone vasculature is essential for many processes, such as skeletal development and growth, bone modeling and remodeling, and healing processes. Endothelium is an integral part of bone tissue, expressing a physiological paracrine function via growth factors and chemokines release, and interacting with several cellular lines. Alterations of the complex biochemical interactions between vasculature and bone cells may lead to various clinical manifestations. Two different types of pathologies result: a defect or an excess of bone vasculature or endothelium metabolism. Starting from the molecular basis of the interactions between endothelial and bone cells, the Authors present an overview of the recent acquisitions in the physiopathology of the most important clinical patterns, and the modern therapeutic strategies for their treatments.

Free vascularised fibular graft for neglected femoral neck fractures in young adults

Neglected femoral neck fractures in young adults pose a great challenge to orthopedic surgeons because of the high risks of nonunion and osteonecrosis. We attempted to determine whether free vascularised fibular grafting through an anterior approach could enhance bone union, improve hip function and reduce complications in the treatment of such fractures. Thirteen patients with neglected femoral neck fractures were treated with a free vascularised fibular graft through an anterior approach between 2004 and 2008. The mean age was 30.9 years (range, 17-47 years). The average delay between injury and operation was 6.7 months (range, 1.5-22 months). All 13 cases had ununited fractures but without osteonecrosis of the femoral head on plain radiographs before coming under our care. The average follow-up was 51.2 months (range, 36-75 months). All patients had fracture union within an average of 4.8 months (range, 3-9 months). Postoperatively, 9 patients had coxa vara of 10 to 20 degrees and leg discrepancy between 0.5 to 1.5 cm. One patient had coxa vara deformity of 25 degrees and 2-cm leg discrepancy. No patients developed osteonecrosis of the femoral head or donor-site morbidity. The mean Harris hip score improved from 55.5 points preoperatively to 84.8 points postoperatively (p<0.01). This procedure may be useful and safe in the treatment of neglected femoral neck fractures in young adults, but further studies with a large number of patients are needed.

Anatomic variations in femoral head circulation

The purpose of this cadaveric study was to clearly define the blood supply to the femoral head to help further reduce the incidence of iatrogenic avascular necrosis (AVN). Thirty-five hips of twenty-eight fresh cadavers were injected with colored silicone. Anterior and posterior dissection was performed to assess the vessels contributing to femoral head vascularity. The medial femoral circumflex artery (MFCA) was found to be the main blood supply to the hip in twenty-nine specimens; the inferior gluteal artery (IGA) was found to be the main blood supply in six. The MFCA consistently provided at least one smaller-calibre inferomedial retinacular artery. The foveal artery provided no significant vascular contribution in any specimen. The quantity and calibre of superior retinacular vessels demonstrated their dominance in head vascularity, although inferior retinacular arteries were consistently present. To reduce the risk of iatrogenic AVN, branches of both the IGA and MFCA traversing the interval between the quadratus femoris and piriformis muscles must be protected during surgery. Since all intracapsular vessels penetrated the capsule near its distal attachment, distal capsulotomy carries a significantly higher risk of AVN than proximal capsulotomy, particularly posterolaterally and inferomedially.

The labrum: structure, function, and injury with femoro-acetabular impingement

BACKGROUND

The recognition of the importance of femoro-acetabular impingement (FAI) as a potential cause of hip pain has been stimulated by major efforts to salvage hip joints by reconstruction to prevent or delay the need for replacement. A previous review addressed the nature of FAI, the various types, and how to make the diagnosis. When FAI occurs, the structure between the femur and acetabular rim, the labrum, is initially impinged upon and subsequently injured.

METHOD

Injury to the labrum should be recognized when treating the osseous causes of FAI. Preserving or recovering labral function, enhancing hip stability and protecting the articular surface, is critical to restoring the hip to normal or near-normal mechanical and physiologic function. The present review collected the varied essential information about the labrum in a succinct manner, independent of treatment algorithms.

RESULTS/CONCLUSION

Advanced knowledge of the labrum is presented, including the anatomy, circulation, histology, embryology, and neurology, as well as how the labrum tears, the types of tears, and how to make the diagnosis. The advantages and limitations of diagnostic magnetic resonance techniques are discussed, including magnetic resonance imaging (MRI), indirect magnetic resonance arthrography (i-MRA), and direct magnetic resonance arthrography (d-MRA). The review recognizes the complexity of the labrum and provides a greater understanding of how the labrum is capable of stabilizing the joint and protecting the articular surface of the hip. This information will act as a guide in developing treatment plans when treating FAI.

Imaging the vascularisation of the femoral head by CT angiography

The femoral head receives its blood supply primarily from the medial femoral circumflex artery, with its deep branch being the most important.

In a previous study, we performed classical anatomical dissections of 16 hips. We have extended our investigation with a radiological study, in which we aimed to visualise the arteries supplying the femoral head in healthy individuals. We analysed 55 CT angiographic images of the hip.

Using 64-row CT angiography, we identified three main arteries supplying the femoral head: the deep branch of the medial femoral circumflex artery and the posterior inferior nutrient artery originating from the medial femoral circumflex artery, and the piriformis branch of the inferior gluteal artery. CT angiography is a good method for visualisation of the arteries supplying the femoral head. The current radiological studies will provide information for further investigation of vascularity after traumatic dislocation of the hip, using CT angiography.

Osteonecrosis of the femoral head: An update in year 2012

Osteonecrosis is a phenomenon involving disruption to the vascular supply to the femoral head, resulting in articular surface collapse and eventual osteoarthritis. Although alcoholism, steroid use, and hip trauma remain the most common causes, several other etiologies for osteonecrosis have been identified. Basic science research utilizing animal models and stem cell applications continue to further elucidate the pathophysiology of osteonecrosis and promise novel treatment options in the future. Clinical studies evaluating modern joint-sparing procedures have demonstrated significant improvements in outcomes, but hip arthroplasty is still the most common procedure performed in these affected younger adults. Further advances in joint-preserving procedures are required and will be widely studied in the coming decade.

Anatomy of the medial femoral circumflex artery with respect to the vascularity of the femoral head

We performed a series of 16 anatomical dissections on Caucasian cadaver material to determine the surgical anatomy of the medial femoral circumflex artery (MFCA) and its anastomoses. These confirmed that the femoral head receives its blood supply primarily from the MFCA via a group of posterior superior nutrient arteries and the posterior inferior nutrient artery. In terms of anastomoses that may also contribute to the blood supply, the anastomosis with the inferior gluteal artery, via the piriformis branch, is the most important. These dissections provide a base of knowledge for further radiological studies on the vascularity of the normal femoral head and its vascularity after dislocation of the hip.

Fluoroscopically guided hip capsulotomy: effective or not? A cadaveric study

OBJECTIVE

The purpose of this study was to examine the efficacy of a fluoroscopically guided hip capsulotomy.

METHODS

Ten fresh-frozen paired cadaveric hips were injected under fluoroscopic guidance with saline sufficient to generate an intra-articular pressure greater than 58 mmHg. The pressure was monitored continuously using a percutaneous transducer. A limited lateral approach to the proximal femur was performed by one of two senior orthopaedic trauma surgeons. Using a scalpel under fluoroscopic guidance, each surgeon made one attempt at an anterior capsulotomy. Changes in intra-articular pressure were recorded throughout the procedure. The specimens were then dissected to measure the extent of each capsulotomy as well as the distance from the capsulotomy to nearby neurovascular structures.

RESULTS

A rapid and substantial decrease in intra-articular pressure was seen in all hips. The mean intra-articular pressure postcapsulotomy was 8.4 mmHg. The capsulotomies averaged 15.1 mm in length. None of the attempts at capsulotomy lasted longer than 90 seconds. The average distance between capsulotomy and the lateral-most branch of the femoral nerve was 19.5 mm. The femoral artery was on average 40.3 mm from the capsulotomy. There was no correlation between the side on which capsulotomy was performed and its extent or proximity to neurovascular structures.

CONCLUSIONS

Fluoroscopically guided hip capsulotomy through a small lateral incision appears to be a safe, effective, and expedient method, which may substantially reduce intra-articular pressure after minimally displaced femoral neck fractures.

Role of the extraosseus blood supply in osteoarthritic femoral heads?

Blood perfusion to the femoral head might be endangered during the surgical approach or the preparation of the femoral head or both in hip resurfacing arthroplasty. The contribution of the intramedullary blood supply to the femoral head in osteoarthritis is questionable. Therefore, the contribution of the extraosseous blood supply to osteoarthritic femoral heads was measured intraoperatively to question if there is measurable blood flow between the epiphysis and metaphysis in osteoarthritic hips in case of extraosseus vessel damage. At defined points during surgery we acquired the epiphyseal and metaphyseal femoral head perfusion by high-energy laser Doppler flowmetry. Complete femoral neck osteotomy sparing the retinacular vessels to simulate intraosseous blood disruption showed unchanged epiphyseal blood flow compared to initial measurement after capsulotomy. The pulsatile signal disappeared after transection of the retinacular vessels. Based on these acute measurements, we conclude intramedullary blood vessels to the femoral head do not provide measurable blood supply to the epiphysis once the medial femoral circumflex artery or the retinacular vessels have been damaged. We recommend the use of a safe surgical approach for hip resurfacing and careful implantation of the femoral component to respect blood supply to the femoral head and neck region in hip resurfacing arthroplasty.

Assessment of vascularity of the femoral head using gadolinium (Gd-DTPA)-enhanced magnetic resonance imaging

In spite of extensive accounts describing the blood supply to the femoral head, the prediction of avascular necrosis is elusive. Current opinion emphasises the contributions of the superior retinacular artery but may not explain the clinical outcome in many situations, including intramedullary nailing of the femur and resurfacing of the hip. We considered that significant additional contribution to the vascularity of the femoral head may exist. A total of 14 fresh-frozen hips were dissected and the medial circumflex femoral artery was cannulated in the femoral triangle. On the test side, this vessel was ligated, with the femoral head receiving its blood supply from the inferior vincular artery alone. Gadolinium contrast-enhanced MRI was then performed simultaneously on both control and test specimens. Polyurethane was injected, and gross dissection of the specimens was performed to confirm the extraosseous anatomy and the injection of contrast. The inferior vincular artery was found in every specimen and had a significant contribution to the vascularity of the femoral head. The head was divided into four quadrants: medial (0), superior (1), lateral (2) and inferior (3). In our study specimens the inferior vincular artery contributed a mean of 56% (25% to 90%) of blood flow in quadrant 0, 34% (14% to 80%) of quadrant 1, 37% (18% to 48%) of quadrant 2 and 68% (20% to 98%) in quadrant 3. Extensive intra-osseous anastomoses existed between the superior retinacular arteries, the inferior vincular artery and the subfoveal plexus.