Lateral femoral circumflex artery contribution to the articular and periarticular hip circulation: relevance to the anterior hip approach-a cadaveric study.

BACKGROUND: The purpose of this cadaveric study was to anatomically demonstrate the contribution of the lateral femoral circumflex artery (LFCA) to the articular and peri-articular hip circulation with an emphasis on the vascularization of hip abductors specially tensor fasciae latae muscle (TFLM). METHODS AND MATERIALS: Thirty hips from 26 fresh cadavers were dissected after injection of the aorta or common iliac artery by colored silicon, to study the contribution of the LFCA to the articular and periarticular hip circulation. Furthermore, the aorta was injected in another 18 fresh cadavers after unilaterally ligating the ascending branch of the LFCA (a-LFCA) as the vascular pedicle of the TFLM, to evaluate the collateral circulation to the TFLM, if available. RESULTS: In all specimens but one, the a-LFCA was found as the single major vascular pedicle of the TFLM. When ligated, only 4 out of 18 hips demonstrated colored cast vessels in the cut surface of the muscle. The ascending branch had also consistent but variable contribution to the gluteus medius and gluteus minimus muscles in 80% of the hips. Furthermore, the a-LFCA consistently supplied the anterior and anterolateral aspects of the hip capsule. In 35% of hips, the a-LFCA contributed to the femoral head and neck circulation via one or two small anterior retinacular arteries. CONCLUSION: LFCA contribution to the articular and periarticular hip circulation is only delivered by the ascending branch. The TFLM is specially perfused by the a-LFCA; its ligation significantly decreases the muscle perfusion. It is poorly supplied by the collateral circulation.

Surgical Anatomy of the Rectus-Sparing Approach for Periacetabular Osteotomy: A Cadaveric Study.

BACKGROUND: The Bernese periacetabular osteotomy (PAO) is a widely used technique for the management of acetabular dysplasia and other hip deformities in adolescents and young adults. Originally, the approach was described with a release of both origins of the rectus femoris muscle1. In the more recently described rectus-sparing approach, both heads remain attached2,3. It has been proposed that this modification may decrease pain, ease postoperative rehabilitation, and avoid heterotopic ossifications, without limitations of the surgical overview. DESCRIPTION: Both the original and the rectus-sparing approach are modifications of the Smith-Petersen approach. The skin incision and further dissection remain identical in both approaches for the protection of the lateral femoral cutaneous nerve, the osteotomy of the anterior superior iliac spine (or takedown of the inguinal ligament), the exposure of the iliac fossa, and the medial retraction of the abdominal and iliopsoas muscles. In both variants, the further dissection traverses the iliopectineal bursa. In contrast to the original approach, in which the rectus muscle becomes part of the medial flap after releasing both heads, the rectus-sparing approach involves the undetached rectus muscle becoming part of the lateral flap while the medial flap includes the sartorius and iliacus-iliocapsularis muscles. The anterior capsule and deep structures can be accessed through the interval between the rectus femoris and iliopsoas muscles or lateral to the rectus muscle. The remaining surgical steps are again similar in both techniques. According to preference, the surgeon starts with the pubic osteotomy or with the ischial cut first, the latter avoiding additional bleeding from the pubic osteotomy. For the ischial osteotomy, the bone is accessed by making an anteroposterior tunnel between the medial capsule and the iliopsoas tendon anteriorly and between the medial capsule and the obturator externus muscle posteriorly. While the ischial osteotomy is an incomplete separation, the pubic osteotomy is a complete separation. It sections the superior pubic ramus medial to the iliopectineal eminence, in a somewhat oblique fashion. The third and fourth cuts are made in the iliac bone in such a way as to keep the posterior column intact. By connecting the posterior iliac and ischial cuts as the last osteotomy step, the acetabulum is freed and repositioned as needed. The aim of our cadaver dissection is primarily to describe part of the rectus-sparing approach and to test this modification for eventual disadvantages over the classic approach. The remaining steps of the procedure correspond to the approach as described earlier1,4, appreciating that several modifications of the procedure are in use. ALTERNATIVES: Nonsurgical treatment may be an alternative in borderline dysplasia; however, it needs to be reconsidered and eventually changed to surgical treatment when symptoms persist or come back. Other current techniques for surgical treatment of adolescent and adult hip dysplasia include triple and rotational or spherical osteotomies5-7. RATIONALE: The Bernese PAO is performed through a single incision. All cuts are performed from the inner side of the pelvis, avoiding interference with the vascularity of the acetabular and periacetabular bone, which mainly comes from the outside of the pelvis8. The procedure needs minimal hardware for fixation, and partial weight-bearing can be allowed. The PAO provides a wide range of acetabular reorientation options. Wide capsulotomy and intra-articular procedures are possible, as well as additional femoral corrections. Childbirth via natural delivery is possible even after bilateral PAO9. Nerve injuries can be guarded against with careful surgical execution of the osteotomies4.

Valgus Slipped Capital Femoral Epiphysis: Pathophysiology of Motion and Results of Intracapsular Realignment.

OBJECTIVES: The purpose of this study was to report (1) a different but specific pattern of impingement in hips involved with valgus slipped capital femoral epiphysis (valgus SCFE) and (2) the results of surgical treatment using intracapsular realignment techniques. DESIGN: Case series. SETTING: Multiple academic centers. PATIENTS: Six patients with 8 involved hips referred for valgus alignment of proximal femoral epiphysis (valgus SCFE). INTERVENTION: Intracapsular realignment osteotomy combined with periacetabular osteotomy if needed. MAIN OUTCOME MEASUREMENT: The clinical and radiographical results and pathophysiology of motion. RESULTS: Eight hips in 6 patients were treated with subcapital (5 hips) or femoral neck (3 hips) osteotomy for realignment. The medially prominent metaphysis created an inclusive impingement at the anterior acetabular wall, whereas the high coxa valga favored impacting impingement at the posterior head-neck junction. The mean preoperative epiphyseal-shaft angle of 110.5 (range 90-125 degrees) was reduced to 62 degrees (range 55-70 degrees) postoperatively. At the last follow-up, all but 1 hip were pain-free and impingement-free, with normal range of motion. One hip was replaced after repeated attempts of correction. The overall hip functional result using modified Merle d'Aubigne scoring system was excellent in 5 hips (18-16 points), good in 2 hips (16-15 points), and poor in 1 hip (6 points). CONCLUSIONS: Impingement in valgus SCFE deformity is specific and complex. Anatomical realignment can lead to favorable results by the restoration of normal morphology and impingement-free range of motion. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Recommendations to Reduce Risk of Nerve Injury During Bernese Periacetabular Osteotomy (PAO).

The Bernese periacetabular osteotomy (PAO) is a widely used procedure to reorient a dysplastic acetabulum resulting from developmental dysplasia of the hip, retroversion, protrusio, or some deformities with a traumatic etiology. Throughout the execution, the lateral femoral cutaneous nerve (LFCN) as well as the obturator, femoral, and sciatic nerves can be injured. Injury to 1 of the 3 major nerves is a devastating event for the patient followed by an ill-defined period of hope for nerve recovery and fear of lifelong disability. Surgical experience is an essential factor in reducing the prevalence of nerve injury, whereas proof of the value of intraoperative fluoroscopy and nerve monitoring still must be established. Although it is known that, for example, the ischial cuts of the complex osteotomy place the sciatic nerve at risk, the action causing the nerve injury is rarely clear in the individual situation. The literature has been mostly limited to reports of incidence and offers little analytic information. Through the use of cadaveric dissections, we visualized the possible impacts of the different steps of the procedure on the nerves in their anatomic vicinity, and the present report demonstrates how nerves can be protected with retractor positioning and how lower-limb positioning can lead to nerve relaxation, an important means to avoid mechanical injury. While the frequent injuries of the LFCN are exclusively related to the approach, sciatic nerve injuries are mainly the result of the ischial osteotomy steps and femoral nerve injuries are seen nearly exclusively with the correction of the acetabular fragment. The authors implemented the demonstrated measures for 9 years, during which approximately 800 periacetabular osteotomies resulted in a total of 2 femoral and 2 sciatic nerve lesions-or a nerve injury rate of 0.5%. The nerves injuries resolved within 6 to 9 months in 3 hips, and 1 patient had a definitive foot drop requiring a splint at the time of writing.

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.

Vascular supply to the acetabular labrum.

BACKGROUND: The acetabular labrum plays an important role in hip joint stability and protection of the articular cartilage of the hip. Despite this, few investigators have evaluated its microscopic vasculature and, to our knowledge, none has assessed its macroscopic blood supply. The purposes of this study were to identify the origin and course of the vascular supply to the acetabular labrum to determine if this blood supply is affected by a labral tear. METHODS: Colored silicone was injected into the vascular tree proximal to thirty-five hips in twenty-eight fresh cadavers. Twenty-four hours after injection, anatomic dissection was performed and the vessels supplying the labrum were followed from their origin to their final distribution. Additionally, labral segments of fifteen randomly selected hips were resected to assess the acetabular rim's vascular contribution, and fifteen hips were dislocated for complete intra-articular inspection of the labrum. RESULTS: Radial branches of a previously described periacetabular periosteal vascular ring were identified as the source of labral blood supply in all thirty-five hips. These branches coursed toward the hip joint on the periosteal surface, penetrated the joint capsule near its innominate insertion, and continued within a loose connective-tissue layer on the capsular surface of the labrum. No contribution from the hip capsule, synovial lining, or osseous acetabular rim could be demonstrated. An intact vascular supply was identified in all seven hips with a labral tear. CONCLUSIONS: The acetabular labrum receives its blood supply from radial branches of a periacetabular periosteal vascular ring that traverses the osseolabral junction on its capsular side and continues toward the labrum's free edge. The hip capsule, the synovial lining, and the osseous acetabular rim do not appear to provide substantial contributions to the labral blood supply.

Capsular and pericapsular contributions to acetabular and femoral head perfusion.

BACKGROUND: Capsular and pericapsular vessels are believed to contribute to acetabular and femoral head perfusion, but, to our knowledge, there is no anatomic study to support this theory. The purpose of this study was to describe the vascular anatomy of the hip with particular reference to the contributions of the capsular and pericapsular vessels. METHODS: Twenty fresh cadavers were dissected twenty-four hours after intra-arterial injection of colored silicone. The arteries supplying the hip were followed by careful dissection from their origins outside the pelvis to their terminal branches. Particular attention was paid to the vessels traveling between the acetabulum and the capsule and the femoral head. RESULTS: In all twenty specimens, the hip capsule received blood supply from the superior and inferior gluteal arteries proximally and from the medial and lateral femoral circumflex arteries distally. The contributory vessels entered the capsule peripherally and superficially. The circumflex arteries supplied the anterior capsule. The gluteal arteries supplied the posterior and posterosuperior aspect of the hip capsule, augmented by contributions from the circumflex arteries. Variable anastomoses were found between the gluteal and femoral systems on the capsular surface beneath the gluteus minimus and short hip external rotators. The medial femoral circumflex artery provided the dominant blood supply to the femoral head in eighteen specimens, and the inferior gluteal artery provided the dominant supply in two specimens. CONCLUSIONS: Capsular and pericapsular vessels that contribute to the blood supply of the acetabulum run on the posterior and posterolateral surface of the capsule. The dominant blood supply to the femoral head comes from vessels that approach the joint posteriorly and penetrate the joint near the femoral attachment of the capsule.

Fibrocystic changes at anterosuperior femoral neck: prevalence in hips with femoroacetabular impingement.

PURPOSE: To retrospectively evaluate if there is an association between juxta-articular fibrocystic changes at the anterosuperior femoral neck and femoroacetabular impingement (FAI). MATERIALS AND METHODS: The institutional review board approved this study and did not require informed patient consent. An orthopedic surgeon and a radiologist in consensus retrospectively reviewed the anteroposterior (AP) pelvic radiographs of 117 hips with FAI and compared these images with the AP radiographs of a control group of 132 hips with developmental dysplasia (DD) to determine the prevalence of juxta-articular fibrocystic changes at the anterosuperior femoral neck. Criteria for juxta-articular fibrocystic changes at the anterosuperior femoral neck were location close to the physis and a diameter (of the fibrocystic change) of greater than 3 mm. The sensitivity and specificity of AP pelvic radiography in the detection of these fibrocystic changes were calculated by using an additional 61 hips with FAI and on the basis of findings at magnetic resonance (MR) arthrography, which was routinely performed for assessment of FAI. In 24 patients who underwent joint-preserving surgery for FAI, the fibrocystic changes were localized intraoperatively and the spatial relation of the region of these changes to the area of FAI was identified. Joint-preserving surgery consisted of anterior surgical dislocation of the hip with osteochondroplasty of the proximal femur and/or the acetabular rim to improve the impingement-free range of hip motion. For statistical comparisons, nonparametric tests were performed. RESULTS: Fibrocystic changes were identified on the AP radiographs of 39 (33%) of the 117 FAI-affected hips and on none of the radiographs of the 132 DD-affected hips. According to MR arthrogram findings, the sensitivity, specificity, and positive and negative predictive values of AP pelvic radiography were 64%, 93%, 91%, and 71%, respectively. The mean diameter of the juxta-articular fibrocystic changes was 5 mm (range, 3-15 mm); smaller lesions were more prevalent. Dynamic MR imaging with the hip flexed and intraoperative observations revealed a close spatial relationship between the region of the fibrocystic changes at the anterosuperior femoral neck and the acetabular rim. CONCLUSION: The high prevalence of juxta-articular fibrocystic changes at the anterosuperior femoral neck and their spatial relation to the impingement site suggest an association and possible causal relationship between these alterations and FAI.

Distribution of vascular foramina around the femoral head and neck junction: relevance for conservative intracapsular procedures of the hip.

Precise knowledge of femoral head vascular anatomy is mandatory for the safe execution of intracapsular surgical procedures aimed at preserving the hip joint. No quantitative topographic data exist concerning the exact location and distribution of the entrance of these vessels through nutrient vascular foramina at the femoral head and neck junction. This study shows that only a few significant retinacular vessels may reach the adult femoral head on its anterior aspect and that most vascular foramina are located close to the antero- and posterosuperior regions of the femoral head and neck junction. This larger segment should be carefully protected during any conservative intracapsular procedure of the hip and may be desirable in femoral head resurfacing arthroplasty.