Radiographic Predictors of Hip Pain in Femoroacetabular Impingement

The primary diagnosis of femoroacetabular impingement is based on clinical symptoms, physical exam findings, and radiographic abnormalities. The study objective was to determine the radiographic findings that correlate with and are predictive of hip pain in femoroacetabular impingement (FAI). One hundred prospective patients with unilateral FAI symptoms based on clinical and radiographic findings were included in this study. All patients filled out a WOMAC pain questionnaire. Two independent-blinded surgeons assessed antero-posterior and lateral radiographs for 33 radiographic parameters of FAI. Correlations between pain scores and radiographic findings were calculated. A matched radiographic analysis was performed comparing symptomatic versus asymptomatic hips. Radiograph findings were also compared between males and females. Weak positive correlations were identified between increasing pain scores with radiographic findings of posterior wall dysplasia, presence of a shallow socket, and a more lateral acetabular fossa relative to the Ilioischial line. A symptomatic hip had a lower neck shaft angle, greater distance from Ilioischial line to acetabular fossa and larger distance from cross-over sign to superolateral point of the acetabulum when compared to the asymptomatic hip in the same patient. Symptomatic hips in males had more joint space narrowing, femoral osteophytes, higher alpha angles and larger, more incongruent femoral heads compared to females. Females had more medial acetabular fossa relative to the Ilioischial line and smaller femoral head extrusion index. Similar to other musculoskeletal conditions, radiographic findings of FAI are poor predictors of hip pain.     

Traumatic posterior hip instability and femoroacetabular impingement in athletes

We describe 3 cases of posterior hip instability associated with femoroacetabular impingement. In each case, we obtained a detailed medical history, performed a physical examination, evaluated imaging, recorded intraoperative findings, and clinically followed the patient for 1 year. Two of the 3 patients sustained a traumatic posterior hip subluxation caused by noncontact injuries. All patients had decreased internal rotation on physical examination, radiographic evidence of acetabular retroversion, a cam lesion, an elevated α angle, and a posterior acetabular rim fracture with associated labral injury. All patients underwent hip arthroscopy and direct repair of the bony acetabular fragment using 3 to 5 suture anchors. One-year follow-up in all cases demonstrated good to excellent results and full return to activities without restriction. Patients with femoroacetabular impingement may be predisposed to traumatic posterior dislocation or subluxation and a concomitant posterior acetabular rim fracture with labral injury. We propose that FAI predisposed these athletes to posterior hip instability.     

Arthroscopic treatment for symptomatic bilateral cam-type femoroacetabular impingement

Arthroscopic femoral osteochondroplasty improves clinical outcome in patients with unilateral cam-type femoroacetabular impingement. The goal of this study was to evaluate the clinical outcome and pathological similarities in patients who have had bilateral arthroscopic femoral osteochondroplasy for cam-type femoroacetabular impingement. The study group included 82 patients who had sequential bilateral hip arthroscopies for symptomatic cam-type femoroacetabular impingement with a minimum of 12 months follow-up. All patients had bilateral restricted hips at presentation. We differentiated between patients who had bilateral painful hips and those with unilateral pain at presentation. Scores and surgical findings were compared between the 2 study groups and between bilateral surgeries in each group. Pre- and postoperative Modified Harris Hip Scores and Non-Arthritic Hip Scores were undertaken prospectively by an independent observer. Mean patient age at the first surgery was 29 years (range, 14-63 years). The average time difference between arthroscopies was 5 months (range, 0.3-30 months). Postoperative scores improved significantly in both study groups in the first and second (contralateral) surgeries. Intra-articular pathologies between sides were linearly correlated for both groups. The time interval between surgeries had a linear correlation to age, reverse correlation to chondral damage, and reverse correlation to postoperative scores at the first surgery. Our results suggest that symptomatic patients with cam-type femoroacetabular impingement have similar accompanied pathologies on both sides and can benefit from sequential arthroscopic osteochondroplasty.     

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.     

Three-dimensional analysis of shoulder girdle and supraspinatus motion patterns in patients with impingement syndrome.

Alterations of the shoulder girdle motion have been suggested to be associated with shoulder disorders. The objective of this study was to perform a three-dimensional (3D) motion analysis of the supraspinatus muscle and shoulder girdle in patients with different stages of impingement syndrome. 20 patients with unilateral impingement and 14 normal controls were investigated at 30 degrees, 90 degrees, and 120 degrees of abduction with and without abducting muscle activity. The spatial relationship between the shoulder girdle elements and the supraspinatus was quantified from open MRI data. No significant alterations in glenoid rotation were observed between the patients and asymptomatic volunteers. However, while in the healthy volunteers the values showed a normal distribution (28.5+/-3.6 degrees at 90 degrees abduction with muscle activity), the patients (30.5 degrees+/-9.7 degrees) contained a subset of five individuals with an obvious increase in glenoid rotation angle (>40 degrees) compared with controls (>2.5 standard deviations higher than the mean) and with the healthy contralateral side. These five patients also displayed alterations in the scapulo-humeral rhythm and supraspinatus motion, but not in clavicular position. The study shows that only a specific subset of patients with impingement syndrome demonstrates complex changes in shoulder girdle and supraspinatus motion patterns, suggesting that this subset may benefit from an alternative type of treatment.     

What Is the Impingement-free Range of Motion of the Asymptomatic Hip in Young Adult Males?

BackgroundFemoroacetabular impingement is a recognized cause of chondrolabral injury. Although surgical treatment for impingement seeks to improve range of motion, there are very little normative data on dynamic impingement-free hip range of motion (ROM) in asymptomatic people. Hip ultrasound demonstrates labral anatomy and femoral morphology and, when used dynamically, can assist in measuring range of motion.Questions/purposesThe purposes of this study were (1) to measure impingement-free hip ROM until labral deflection is observed; and (2) to measure the maximum degree of sagittal plane hip flexion when further flexion is limited by structural femoroacetabular abutment.MethodsForty asymptomatic adult male volunteers (80 hips) between the ages of 21 and 35 years underwent bilateral static and dynamic hip ultrasound examination. Femoral morphology was characterized and midsagittal flexion passive ROM was measured at two points: (1) at the initiation of labral deformation; and (2) at maximum flexion when the femur impinged on the acetabular rim. The mean age of the subjects was 28 ± 3 years and the mean body mass index was 25 ± 4 kg/m².ResultsMean impingement-free hip passive flexion measured from full extension to initial labral deflection was 68° ± 17° (95% confidence interval [CI], 65–72). Mean maximum midsagittal passive flexion, measured at the time of bony impingement, was 96° ± 6° (95% CI, 95–98).ConclusionsUsing dynamic ultrasound, we found that passive ROM in the asymptomatic hip was much less than the motion reported in previous studies. Measuring ROM using ultrasound is more accurate because it allows anatomic confirmation of terminal hip motion.

Clinical Significance

Surgical procedures used to treat femoroacetabular impingement are designed to restore or increase hip ROM and their results should be evaluated in light of precise normative data. This study suggests that normal passive impingement-free femoroacetabular flexion in the young adult male is approximately 95°.     

Femoroacetabular impingement and risk factors: a study of 50 cases

Objective: To study the asphericity of the femoral head in femoroacetabular impingement using the radiological indices alpha angle and triangular index, and correlation with risk factors. Methods: The study was conducted retrospectively from January 2008 to June 2010 on 50 consecutive patients with suspected cam type femoroacetabular impingement of the hip who reported to the orthopaedics outpatients department of the Postgraduate Institute of Medical Education and Research. Ten controls were also used in the study. Radiographs of the affected hip were taken and then the alpha angle and triangular index were measured and correlated with various risk factors. Results: In the anteroposterior view the alpha angle range was from 55° to 106° for the cases and from 54° to 70° for the controls. In the lateral view the range was from 62° to 104° for the cases and from 54° to 62° for the controls. The mean alpha angle in the anteroposterior view was measured as 75°± 10° in the cases and 61°± 6° in the controls, and the mean in the lateral view was 74°± 8° in the cases and 58°± 6° for the controls. The triangular index range in the radiographs was from 1 to 7 in the cases and from 0 to 1 for the controls. The mean triangular index in the radiographs was 2.9 ± 1.2 for the cases and 0.2 ± 0.4 for the controls. Conclusion: There was no significant correlation between the age and gender of the patient and the femoroacetabular impingement. However, there was significant correlation between the body mass index of the patient and the femoroacetabular impingement.     

Femoroacetabular impingement: a cause for osteoarthritis of the hip

A multitude of factors including biochemical, genetic, and acquired abnormalities may contribute to osteoarthritis of the hip. Although the pathomechanism of degenerative process affecting the dysplastic hip is well understood, the exact pathogenesis for idiopathic osteoarthritis has not been established. Based on clinical experience, with more than 600 surgical dislocations of the hip, allowing in situ inspection of the damage pattern and the dynamic proof of its origin, we propose femoroacetabular impingement as a mechanism for the development of early osteoarthritis for most nondysplastic hips. The concept focuses more on motion than on axial loading of the hip. Distinct clinical, radiographic, and intraoperative parameters can be used to confirm the diagnosis of this entity with timely delivery of treatment. Surgical treatment of femoroacetabular impingement focuses on improving the clearance for hip motion and alleviation of femoral abutment against the acetabular rim. It is proposed that early surgical intervention for treatment of femoroacetabular impingement, besides providing relief of symptoms, may decelerate the progression of the degenerative process for this group of young patients.     

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.     

Postoperative assessment of vascularity of the femoral head after surgical hip dislocation

Treatment for femoroacetabular impingement includes surgical hip dislocation and recontouring the femoral head-neck junction. However, a potential complication of this procedure is avascular necrosis. The purpose of this study was to assess radiographically the vascularity of the femoral head after surgical hip dislocation. Ten patients underwent surgical hip dislocation and recontouring of the femoral head-neck junction for femoroacetabular impingement. Postoperatively, all 10 patients underwent magnetic resonance imaging of the hip. Magnetic resonance imaging revealed no evidence of osteonecrosis in all patients. This study provides clear radiographic evidence that surgical hip dislocation may be performed without causing avascular necrosis of the femoral head.     

Editorial Commentary: At the Intersection of Borderline Dysplasia and Femoroacetabular Impingement—Which Way Should We Turn?

Borderline acetabular dysplasia remains a controversial topic in hip preservation, with poor current comparative literature to guide accurate diagnosis and treatment decision making. Borderline dysplasia represents a “transitional acetabular coverage” pattern between more classic acetabular dysplasia and normal coverage. Traditionally, borderline dysplasia has been defined by a lateral center-edge angle between 20° and 25°, whereas more recently, some authors have used 18° to 25°. Treatment decisions between isolated hip arthroscopy (addressing labral tears, femoroacetabular impingement morphology, and capsular laxity) and periacetabular osteotomy (improving joint stability, often combined with arthroscopy) remain challenging because the fundamental mechanical diagnosis (instability vs femoroacetabular impingement) can be difficult to determine clinically. Obtaining an accurate diagnosis to direct surgical treatment relies on comprehensive assessment of additional bony anatomy features (including femoral version) and patient characteristics (including sex, soft-tissue laxity, and range of motion). Future research efforts in borderline dysplasia should better characterize the role of disease- and patient-specific factors that will inform accurate diagnoses, leading to the development of optimal treatment strategies in distinct patient subgroups through comparison of treatment outcomes.     

Shoulder rhythm in patients with impingement and in controls: Dynamic RSA during active and passive abduction

Background and purpose Impingement syndrome is probably the most common cause of shoulder pain. Abnormal abduction and proximal humeral translation are associated with this condition. We evaluated whether the relative distribution between glenohumeral and scapular-trunk motions (the scapulohumeral rhythm) and the speed of motion of the arm differed between patients with impingement and a control group without shoulder symptoms.Patients and methods 30 patients with shoulder impingement (Neer stage 2) and 11 controls were studied during active abduction and 21 patients and 9 controls were studied during passive abduction. Dynamic RSA at a speed of 2 simultaneous exposures per second was used to record the shoulder motions for 5–6 seconds.Results Within the interval statistically evaluated (observations between 20–55° of relative active abduction in the glenohumeral joint), the patient group showed more scapular and trunk motions (p = 0.04), especially at up to 40°. The pattern of motion at passive abduction was somewhat similar to that in the controls.Both controls and patients showed an increasing absolute (i.e. global) proximal displacement of the center of the humeral head with increasing active and passive abduction of the glenohumeral joint and humerus, without any certain difference between the groups. The mean maximum absolute proximal displacement in the patient and control groups amounted to about 30 mm and 20 mm, respectively. The corresponding relative displacement (with fixed scapula) was only 2.0 and 0.5 mm.Active abduction was initiated with angular velocity of about 50 and 80 degrees per second, respectively, in the patients and the controls. In both groups it decreased with progressing abduction down to about 20 degrees per second (controls) after 3 seconds without there being any statistically significant difference. The angular velocities at passive abduction showed a similar pattern, still without any difference.In both groups, the speed of proximal translation during active abduction peaked 0.5–1 second later than the speed of rotation and remained relatively even for about 1 second, followed by a deceleration.Interpretation We found that the glenohumeral-thoracoscapular ratio during abduction of the arm in our study, measured as the distribution of motion between the glenohumeral joint and the trunk in both controls and patients with impingement, was less than or equal to 1:1. This finding differs from earlier results, probably due to the use of a method with high resolution and small influence of motions out of the frontal plane. The reason for reduced glenohumeral motions in the early phase of active abduction in the patient group is uncertain, but pain or avoidance of pain elicited by the motion was probably of importance.     

Physiotherapy for sleep disturbance in chronic low back pain: a feasibility randomised controlled trial

Background

The aims of this study were to evaluate the construct validity (known group), concurrent validity (criterion based) and test-retest (intra-rater) reliability of manual goniometers to measure passive hip range of motion (ROM) in femoroacetabular impingement patients and healthy controls.

Methods

Passive hip flexion, abduction, adduction, internal and external rotation ROMs were simultaneously measured with a conventional goniometer and an electromagnetic tracking system (ETS) on two different testing sessions. A total of 15 patients and 15 sex- and age-matched healthy controls participated in the study.

Results

The goniometer provided greater hip ROM values compared to the ETS (range 2.0-18.9 degrees; P < 0.001); good concurrent validity was only achieved for hip abduction and internal rotation, with intraclass correlation coefficients (ICC) of 0.94 and 0.88, respectively. Both devices detected lower hip abduction ROM in patients compared to controls (P < 0.01). Test-retest reliability was good with ICCs higher 0.90, except for hip adduction (0.82-0.84). Reliability estimates did not differ between the goniometer and the ETS.

Conclusions

The present study suggests that goniometer-based assessments considerably overestimate hip joint ROM by measuring intersegmental angles (e.g., thigh flexion on trunk for hip flexion) rather than true hip ROM. It is likely that uncontrolled pelvic rotation and tilt due to difficulties in placing the goniometer properly and in performing the anatomically correct ROM contribute to the overrating of the arc of these motions. Nevertheless, conventional manual goniometers can be used with confidence for longitudinal assessments in the clinic.     

Arthroscopically assisted anterior decompression for femoroacetabular impingement: technique and early clinical results

Introduction  In patients with symptomatic femoroacetabular impingement resection osteochondroplasty of the femoral head–neck junction may improve hip pain and range of motion. We evaluated the short-term treatment results of an arthroscopically assisted mini-open anterior approach to compare it with the results after surgical dislocation for FAI. Methods  The clinical and radiographic results of 33 patients were reviewed retrospectively 15 months after the surgery. Harris hip scores and plain radiographs were obtained preoperatively and at follow-up. Patient satisfaction with the treatment result was quantified with a Visual Analogous scale (VAS) ranging from 0 (very dissatisfied) to 10 (very satisfied). Results  The mean Harris hip score improved from 64 points preoperatively to 85 points at the time of follow-up (P < 0.001). Mean patient satisfaction on the VAS was seven points (range: 2–10 points). In two of our first patients we observed a transient femoral nerve palsy (completely resolved at follow-up) and 15 patients reported numbness in the area of the lateral cutaneous femoral nerve. Conclusions  Treatment of anterior femoroacetabular impingement through an arthroscopically assisted mini-open anterior approach can reduce pain and improve function in a short-term observation period. Femoral osteochondroplasty as well as surgical treatment of acetabular cartilage and labrum lesions are possible, but the access is limited to the anterior and anterolateral part of the hip joint.     

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.     

Pelvic posture and kinematics in femoroacetabular impingement: a systematic review

Pelvic posture and kinematics influence acetabular orientation and are therefore expected to be involved in the pathomechanics of femoroacetabular impingement (FAI). This systematic review aims to determine whether FAI patients show pelvic postures or patterns of motion contributing to impingement or, conversely, develop compensatory postures and patterns of motion preventing it. PubMed/MEDLINE, Embase, Google Scholar and the Cochrane Library were systematically searched to find all the studies that measured pelvic positional and/or kinematic data in humans (patients or cadaveric specimens) affected by FAI. Twelve items were selected and grouped according to the main field of investigation. No quantitative data synthesis was allowed due to methodological heterogeneity. Pelvic posture and kinematics seem to play a relevant role in FAI. The patients, especially if symptomatic, show a paradoxical lack of pelvic back tilt in standing hip flexions, i.e., in squatting, that enhances femoroacetabular engagement. Such an aberrant pattern might depend on a lower pelvic incidence. On the contrary, active hip flexion in decubitus elicits a compensatory, more pronounced back tilt to facilitate hip flexion without impingement. Stair climbing shows a compensatory pattern of augmented pelvic axial rotation and augmented peak forward tilt to reduce painful hip motions, namely internal rotation and extension. In FAI patients, pelvic posture and kinematics are sometimes an expression of compensatory mechanisms developed to reduce pain and discomfort, and sometimes an expression of paradoxical responses that further enhance the impingement pathomechanism. IV.     

Internal impingement of the shoulder: comparison of findings between the throwing and nonthrowing shoulders of college baseball players.

The authors evaluated and compared the findings of gadolinium-enhanced magnetic resonance imaging (MRI) studies of throwing and nonthrowing shoulders in college baseball athletes and contrasted these findings with the clinical examination results. Ten throwing college baseball athletes were prospectively clinically examined for instability, range of motion, impingement signs, and relocation testing, then evaluated with bilateral gadolinium enhanced MRI using the nonthrowing shoulder as a control. All MRIs were performed on a 1.5-Tesla magnet and included routine adduction images and images obtained in abduction and external rotation (ABER). Studies were interpreted by a musculoskeletal radiologist and an orthopaedic surgeon specializing in shoulder surgery. In all shoulders, ABER imaging showed physical contact between the undersurface of the rotator cuff and the posterior superior glenoid. No imaging or physical examination abnormalities were identified in the nonthrowing shoulders. Three of 10 throwing shoulders had superior labral tears and adjacent paralabral cysts extending toward or into the spinoglenoid notch. Four of 10 throwing shoulders had abnormal signal change in the rotator cuff tendons. No correlation was identified between positive MRI findings and instability on physical examination. Physical contact between the rotator cuff undersurface and the subjacent labrum can be seen normally in the ABER position. Abnormalities of the rotator cuff and superior labrum are seen in asymptomatic throwing shoulders but not nonthrowing shoulders. MRI abnormalities consistent with internal impingement can be seen in asymptomatic patients. Treatment of these abnormalities in young throwing athletes should be approached with caution.