Anterior femoroacetabular impingement: part I. Techniques of joint preserving surgery

The exact pathomechanism responsible for osteoarthritis (OA) of the nondysplastic hip has remained unknown for many years. There is, however, emerging clinical evidence implicating femoroacetabular impingement as an etiologic factor for having early OA of the hip develop. Femoroacetabular impingement is an abutment conflict occurring between the proximal femur and the acetabular rim arising from morphologic abnormalities affecting the acetabulum or the proximal femur, or both. The repetitive mechanical conflict occurring during motion, particularly flexion and internal rotation, can lead to lesions of acetabular labrum and, even more serious, the adjacent acetabular cartilage. Surgical treatment of femoroacetabular impingement focuses on improving the clearance for hip motion and alleviation of femoral abutment against the acetabular rim. We will describe the rationale for the treatment of this condition, and discuss the technique of joint-preserving surgery.     

Current concepts in the treatment of adolescent femoroacetabular impingement

There is growing evidence that symptomatic femoroacetabular impingement leads to intra-articular damage and the development of early-onset osteoarthritis. Symptoms of femoroacetabular impingement often do not manifest until adulthood, but have been increasingly recognised in the paediatric and adolescent population. The surgical treatment of femoroacetabular impingement is aimed at restoring a more normal femoral head–neck offset in order to increase the clearance and prevent femoral abutment against the acetabular edge. Current methods include open and arthroscopic techniques. The latter has been combined with an open approach to gain access to the head–neck junction for osteochondroplasty. Proximal femoral and/or periacetabular osteotomies are used to treat femoroacetabular impingement associated with deformity secondary to childhood hip conditions, such as slipped capital femoral epiphysis and Legg–Calvé–Perthes disease. Some adolescents have severe degenerative joint disease at the time of presentation and may require arthroplasty or arthrodesis. The aim of this review is to identify the major trends and advancements in the management of femoroacetabular impingement in adolescents, including the outcome of studies of the surgical treatment modalities used.     

Young adult hip disease: hip morphology and impingement

Normal hip development is vital for the normal biomechanics of the hip joint. Gross deformity is well known to lead to early-onset osteoarthritis. There is an increasing appreciation of the importance of more subtle changes in hip morphology, which can also be predisposing factors for degenerative wear of the hip. Careful examination and imaging of young adults presenting with hip pain is paramount to identifying femoroacetabular impingement early, at a stage when joint preserving techniques can be of benefit.This article will discuss the different types of hip impingement, their clinical and radiological features and the current treatment options available.     

Surgical management of healed slipped capital femoral epiphysis

Slipped capital femoral epiphysis (SCFE) results in posterior and inferior displacement of the epiphysis on the femoral neck. In most centers, the recommended initial management of stable SCFE is in situ pinning. Minimal reduction with in situ pinning is recommended for unstable SCFE. This approach does not restore the normal anatomy of the hip joint, and the resulting proximal femoral deformity may cause femoroacetabular impingement. Patients with femoroacetabular impingement experience reduced hip range of motion as well as hip pain, and they are at risk of early-onset hip osteoarthritis. Techniques for managing this deformity include arthroscopic femoral neck osteochondroplasty, a limited anterior hip approach or surgical hip dislocation, and flexion intertrochanteric osteotomy. These surgical techniques should be considered for patients with healed SCFE deformity who present with hip pain at an early age.     

Histopathologic features of the acetabular labrum in femoroacetabular impingement

This paper summarizes clinical and histopathologic findings derived from 25 patients who had surgery for symptomatic femoroacetabular impingement. We explored if observed pathologic features were consistent with hypothesized mechanisms of injury, if severity of osteoarthritis and labral degeneration were associated, and if labral refixation would present an alternative. Clinically, all patients presented with limited range of motion at the hip attributable to pain and a positive impingement test. Magnetic resonance arthrography and surgical observations showed degenerated or ruptured labra or both in the anterior and/or superior regions of the acetabular rim (24 of 25 specimens) which correlated with pain provocation, limited range of motion, and anatomic deformities. Histologically, labra were mostly hyperplastic with disorganized cystic matrices. No inflammation was observed. Spatial distribution of degenerated labral matrices was not different for the two femoroacetabular impingement mechanisms. Labral degeneration and severity of osteoarthritis observed on radiographs did not correlate. In patients having only joint debridement, the labral matrix at the tip, near its vascular supply, was normal. Femoroacetabular impingement is a gentle chronic irritation of the labra located at the site of rupture that elicits a degenerative reaction. In early stages of the disease, the labral tip is not involved, providing the possibility of labral refixation after resection of the degenerated portion.     

Editorial Commentary: Hip Arthroscopy Outcomes in Older Patients Can Equal Outcomes in Younger Patients With Proper Surgical Indications

Hip arthroscopy patients often present with clinical features that help broadly categorize them as the younger patient with femoroacetabular impingement, the microinstability- or instability-related patient, those patients with predominant peripheral compartment disease, and the older patient with femoroacetabular impingement plus peripheral compartment disease. Outcomes in older patients can equal outcomes in younger patients with proper surgical indications. Specifically, older hip arthroscopy patients do well in the absence of degenerative articular cartilage changes. Although some studies have suggested a potential for greater conversion rate to hip arthroplasty in an older age group, with proper patient selection, hip arthroscopy may lead to durable and significant improvements.     

Hip–Spine Syndrome in the Nonarthritic Patient

Hip–spine syndrome refers to concurrent hip and spine pathology with overlapping symptoms. Most of the literature has studied it in relation to total hip arthroplasty literature and has been shown to increase dislocation risk. Lumbar spine and pelvic mobility have been studied less frequently in relation to nonarthritic pathologic hip states. Understanding the biomechanical relationship between the lumbar spine, pelvis, and hip can help elucidate how hip–spine syndrome affects the nonarthritic hip and how it impacts outcomes of hip arthroscopy. Changes in lumbar spine motion may be the reason certain predisposed patients develop symptomatic femoroacetabular impingement (FAI) or ischiofemoral impingement. Some athletes may be “hip users” with a low pelvic incidence, making them more reliant on hip motion due to less-intrinsic lumbopelvic motion. When these patients have FAI morphology, their increased reliance on hip motion makes them prone to experiencing femoroacetabular contact and concurrent symptoms. Other athletes may be “spine users,” with larger pelvic incidence and more baseline lumbopelvic motion, making them less reliant on hip motion and therefore less prone to experiencing hip impingement even with hip FAI morphology. Hip–spine syndrome also appears to have an impact on patient selection, role of nonoperative treatment, and hip arthroscopy surgical outcomes. Identifying patients with concurrent pathology may allow surgeons to recommend targeted physical therapy or counsel patients better on their expectations after surgery.     

股髋撞击综合征病理特点和诊断现状研究

髋关节疼痛和髋骨性关节炎病理机制是多因素的,近年来股髋撞击综合征被认为会造成这些症状,而且有可能是髋骨性关节炎潜在原因。准确的诊断该病是手术矫形成功的基础。本文综述了股髋撞击综合征的分型、病理碰撞机制和诊断现状,并进一步探索了诊断该病所需X线片要求和多个参数如髋臼旋转、α角、头颈偏心距、偏心指数等,将有助于提高该病的诊断率,并合理地制定治疗方案,使髋关节疾病的治疗效果得到提高。     

髋关节镜治疗股骨髋臼撞击征的研究进展

股骨髋臼撞击征是近10余年才被逐渐认识的一种髋关节疾病,也是年轻人髋部疼痛的常见病因之一,其会导致髋关节运动过程中异常应力接触,这种病理力学机制与早期骨关节炎的发展密切相关。手术本身主要针对于病因进行治疗。随着关节镜技术和可折弯器械的发展,髋关节镜运用得越来越广泛,患者创伤小、术后康复较快且并发症发生率较低,短期和中期的效果令人满意,单纯盂唇修复的效果也优于单纯清理术,但是这些尚需要长期和大样本量的结果来进行随访。     

An examination of the association between different morphotypes of femoroacetabular impingement in asymptomatic subjects and the development of osteoarthritis of the hip

We retrospectively examined the long-term outcome of 96 asymptomatic hips in 96 patients with a mean age of 49.3 years (16 to 65) who had radiological evidence of femoroacetabular impingement. When surveillance commenced there were 17, 34, and 45 hips with cam, pincer, and mixed impingement, respectively. Overall, 79 hips (82.3%) remained free of osteoarthritis for a mean of 18.5 years (10 to 40). In contrast, 17 hips (17.7%) developed osteoarthritis at a mean of 12 years (2 to 28). No statistically significant difference was found in the rates of development of osteoarthritis among the three groups (p = 0.43). Regression analysis showed that only the presence of idiopathic osteoarthritis of the contralateral diseased hip was predictive of development of osteoarthritis on the asymptomatic side (p = 0.039). We conclude that a substantial proportion of hips with femoroacetabular impingement may not develop osteoarthritis in the long-term. Accordingly, in the absence of symptoms, prophylactic surgical treatment is not warranted.     

Can we predict the natural course of femoroacetabular impingement?

We conducted a multivariate regression analysis (including both radiographic and activity related variables) in patients with osteoarthritis of the hip and structural changes related with femoroacetabular impingement. The purpose of this study was to investigate whether the age at which total hip arthroplasty may have to be performed, can be predicted in patients with femoroacetabular impingement (FAI). In 121 patients with FAI-related osteoarthritis, radiographic variables describing FAI-related parameters were obtained and the patients were questioned about their activity during early adulthood by means of the validated Baecke et al questionnaire. None of the variables significantly correlated with the final outcome parameter : age at surgery. As expected, based on the low correlation ratios of the different parameters investigated, a multiple-regression model was not accurate enough to allow any prediction on the natural course of FAI. We found that it is difficult to accurately predict the age at which a patient with FAI will develop early osteoarthritis. From our findings it appears that a hip with FAI is not always prone to early end-stage osteoarthritic degeneration, not even in patients with a high level of physical activity. Hence, considering the high prevalence of FAI-related radiographic findings, we conclude that not every radiographic abnormality requires treatment.     

Trends in femoroacetabular impingement research over 11 years

Femoroacetabular impingement is the abutment between the proximal femur and the rim of the acetabulum. It is a common cause of labral injury that has been identified as an early cause of hip osteoarthritis. The diagnosis of femoroacetabular impingement of the hip is currently well defined in orthopedic surgery but should attract the attention of physicians in other disciplines. Conversely, much less is known about the etiology and natural history of femoroacetabular impingement.The goal of this study was to assess the number of articles published on femoroacetabular impingement over 11 years in orthopedic vs nonorthopedic medical journals, and to evaluate the quality of available evidence. PubMed and OvidSP databases were searched for articles on femoroacetabular impingement published from 1999 to 2009. Articles were characterized by publication type and journal type per year. Regression analysis was used to determine the effect of publication year on number of publications of each type. The search yielded 206 publications on femoroacetabular impingement during the evaluation period. Seventy-two percent were published in orthopedic journals. Overall, the number of publications increased exponentially with time. There was an increase in clinical trials over the course of the study period. However, studies with high-quality evidence were scarce. The increase in data from orthopedic and nonorthopedic disciplines is welcome. Nevertheless, high-quality evidence on femoroacetabular impingement is lacking. We believe the current trend toward evidence-based orthopedic surgery will impact future research on this relatively new disorder.     

Femoroacetabular impingement

Evidence is emerging that subtle morphologic abnormalities around the hip, resulting in femoroacetabular impingement, may be a contributing factor in some instances to osteoarthritis in the young patient. The morphologic abnormalities result in abnormal contact between the femoral neck/head and the acetabular margin, causing tearing of the labrum and avulsion of the underlying cartilage region, continued deterioration, and eventual onset of arthritis. Nonsurgical treatment typically fails to control symptoms. Surgical management involves dislocation of the hip (while preserving the blood supply to the femoral head) and femoroacetabular osteoplasty. Encouraging results have been reported following femoroacetabular osteoplasty and arthroscopic treatment of femoroacetabular impingement.     

Low Early Failure Rates Using a Surgical Dislocation Approach in Healed Legg-Calvé-Perthes Disease

Background  

Hip deformity secondary to Legg-Calvé Perthes disease (LCPD) may result in femoroacetabular impingement (FAI) and ultimately osteoarthritis. Observations made with the surgical hip dislocation approach have improved our understanding of the pathologic mechanics of FAI. However, owing to concerns about complications related to the vascularity, the role of surgical hip dislocation in the treatment of healed LCPD remains controversial.     

Anterior femoroacetabular impingement after femoral neck fractures

OBJECTIVES: To verify whether anterior femoroacetabular impingement can be a reason for hip pain and loss of motion in patients with a healed femoral neck fracture. DESIGN: Retrospective clinical, radiologic, and surgical evaluation. SETTING: Third referral hospital. PATIENTS: Nine patients who previously sustained a femoral neck fracture were treated between 1995 and 1999 for hip pain and loss of motion. All these mostly young patients (mean age 33.3 years) complained of groin pain. During the physical examination, acute pain could be elicited by passively forcing the femoral neck against the acetabular rim in flexion, adduction, and internal rotation, motions that were all limited. METHODS: Conventional radiographs and, if possible, arthrographic magnetic resonance imaging scans were followed by a surgical subluxation or dislocation of the femoral head to analyze the sequelae of anterior femoroacetabular impingement. Treatment was based on improvement of the anterior offset (the difference between the anterior contour of the head and the femoral neck) or intertrochanteric osteotomy to ameliorate clearance of the joint. RESULTS: Intraoperatively in eight patients (one not operated), impingement was found to result from insufficient reduction of the fracture, already visible on the conventional radiographs. Retrotorsion (mean 20 degrees) of the head caused anterior impingement in all patients, additional varus position (mean caput collum diaphysis angle 115 degrees) of the head caused anterolateral impingement in two patients. In all patients, anterior labral and adjacent acetabular cartilage lesions were found during surgical subluxation or dislocation of the femoral head, comparable to those seen on the magnetic resonance imaging scan. They proved to result from repetitive abutment and compression between the head-neck junction and the acetabulum. CONCLUSION: Femoroacetabular impingement can be a cause for hip pain and loss of motion in patients who previously sustained a femoral neck fracture. The condition causes degenerative anterior labral and adjacent acetabular cartilage lesions. Early treatment is essential to prevent further degeneration and osteoarthrosis of the joint. Prevention is predicated by initial precise anatomic reduction of such fractures in all planes.