Femoroacetabul�res Impingement

Surgical Hip Dislocation in the Era of Hip Arthroscopy Demonstrates High Survivorship and Improvements in Patient-reported Outcomes for Complex Femoroacetabular Impingement

BACKGROUND

Over the past decade, hip arthroscopy has become more commonly used in the treatment of patients with femoroacetabular impingement (FAI) as well as those with many other intra-articular hip pathologies. As such, the indications for open surgical hip dislocation have narrowed to include complex intra-articular and extra-articular bony morphologies and revision hip preservation. Although surgical hip dislocation has been established as an effective approach, previous research using contemporary indications has been limited primarily to smaller cohorts with short-term follow-up. Furthermore, factors associated with reoperation, conversion arthroplasty, and not achieving clinical improvement remain ambiguous.

QUESTIONS/PURPOSES

At a minimum of 2 years of follow-up in patients treated for FAI with surgical hip dislocation, (1) how much did patient-reported outcome measures (PROMs) improve, and what percentage of patients achieved the minimum clinically important difference (MCID) and patient-acceptable symptom state (PASS)? (2) What was the survivorship free from reoperation of the hip for any reason? (3) What was the survivorship free from conversion to arthroplasty (THA or hip resurfacing)?

METHODS

Between February 2011 and April 2021, 211 patients were treated at one academic institution with surgical dislocation and osteoplasty of the femoral head-neck junction or greater trochanter for FAI. Of these, patients with concomitant diagnoses including Legg-Calvé-Perthes disease, slipped capital femoral epiphysis, osteochondritis dissecans, a benign tumor, or another neurologic or metabolic disorder were excluded. This yielded 74% (156 of 211) of patients as potentially eligible. A further 12% (18 of 156) of patients without postoperative PROMs were excluded, and another 13% (21 of 156) were lost before the minimum study follow-up of 2 years, leaving 75% (117) for analysis at a median of 4.9 years (range 2 to 12 years) in this retrospective study. A total of 88% of the patients were women (103 of 117), and 40% (47 patients) underwent the procedure as a revision. All patients underwent surgical hip dislocation. Intraoperatively, 66% (77 of 117) of patients demonstrated cam impingement, and the remainder had either pincer impingement or combined cam and pincer; 82% (96 of 117) had some component of extra-articular impingement. To answer our first research question, we obtained PROM scores for the modified Harris hip score (mHHS) and international hip outcome tool 12 (iHOT-12) before surgery and at the most-recent follow-up from our longitudinally maintained institutional database, and we determined the percentage of patients who achieved the MCID or PASS. To answer our second research question, we calculated Kaplan-Meier survivorship free from any reoperation on the hip at 5.8 years (mean follow-up) after the index procedure. To answer our third research question, we calculated the Kaplan-Meier survivorship free from conversion to arthroplasty at 5.8 years. Using univariate logistic regression analysis, factors associated with meeting these defined endpoints were identified.

RESULTS

At a mean of 6 ± 3 years, the mHHS of patients treated with surgical hip dislocation for FAI who had not had previous surgery on the hip improved from 53 ± 15 to 85 ± 13 (mean difference 31 [95% confidence interval 27 to 36]; p < 0.01) and the mean iHOT-12 score improved from 25 ± 14 to 74 ± 24 (mean difference 49 [95% CI 42 to 56]; p < 0.01). At a mean of 5 ± 3 years, for patients with prior hip surgery, mHHS improved from 55 ± 13 to 79 ± 15 (mean difference 24 [95% CI 18 to 30]; p < 0.01) and iHOT-12 scores improved from 25 ± 16 to 66 ± 26 (mean difference 41 [95% CI 31 to 50]; p < 0.01). The proportion of patients who achieved the MCID for the mHHS was 87% (55 of 63) and 83% (33 of 40), while the proportion who achieved the PASS for the mHHS was 66% (46 of 70) and 51% (24 of 47) for primary and revision surgery, respectively. The proportion of patients who achieved the MCID for the iHOT-12 was 87% (53 of 61) and 83% (33 of 40), while the proportion who achieved the PASS for iHOT-12 was 68% (47 of 69) and 57% (26 of 46) for primary and revision surgery, respectively. Higher lateral center-edge angles (odds ratio 1.2 per 1° [95% CI 1.1 to 1.3]; p < 0.01), a lower acetabular version at 2:00 (OR 0.92 per 1° [95% CI 0.85 to 0.99]; p = 0.05), the absence of a labral tear (OR 0.21 [95% CI 0.06 to 0.79]; p = 0.02), a higher preoperative mHHS (OR 1.1 per 1 point [95% CI 1.02 to 1.2]; p < 0.01), and a higher preoperative iHOT-12 score (OR 1.1 per 1 point [95% CI 1.01 to 1.1]; p = 0.01) were associated with not achieving the MCID. In patients without a history of ipsilateral hip surgery, survivorship free from reoperation at 5.8 years after surgical hip dislocation was 90% (95% CI 82% to 98%). In the setting of prior ipsilateral hip surgery, survivorship free from reoperation at 5.8 years after surgical hip dislocation was 75% (95% CI 60% to 95%). No patients for whom surgical hip dislocation was their primary hip procedure underwent conversion to arthroplasty. Among the revision patient cohort, survivorship free from conversion to arthroplasty at 5.8 years after surgical hip dislocation was 97% (95% CI 91% to 100%).

CONCLUSION

Surgical hip dislocation effectively improves hip pain and function with high survivorship (free of reoperation or conversion to arthroplasty) for complex intra-articular and extra-articular FAI that is deemed less suitable for arthroscopic treatment, but when the procedure is used in patients who have had prior hip surgery, they should be told that revision surgery is a realistic possibility. If insufficient acetabular coverage is anticipated, acetabular reorientation osteotomy should be considered. Future studies should evaluate long-term survivorship and PROMs in larger patient cohorts, as well as identify other factors associated with reoperation and conversion to arthroplasty.

LEVEL OF EVIDENCE

Level III, therapeutic study.

The critical importance of recognition, evaluation, and management of mental health on outcomes following hip arthroscopy - A synthetic narrative review: Current concepts

Mental health and wellness influence patients with hip pain and dysfunction secondary to Femoroacetabular Impingement Syndrome, acetabular dysplasia, and labral injury. Disorders of mental wellness may impact hip preservation surgery patients both before and after surgery. Major depression and generalized anxiety are the two most common diagnoses that affect hip preservation surgery patients. There are dozens of unique questionnaires that can subjectively and objectively characterize the mental health of patients with hip pain. Pain threshold and pain tolerance are two issues that must be recognized to optimally predict treatment outcome in an informed consent shared decision-making discussion. Patient expectations may also significantly influence preoperative symptoms and postoperative outcome. Pain threshold, pain tolerance, and patient expectations are entities traditionally viewed as qualitative and unmeasurable. However, many valid and reliable methods exist to quantitatively assess these patient-specific variables. Recent original research and synthetic review publications have consistently concluded similar findings: patients with disorders of mental wellness generally have lower preoperative patient-reported outcome scores, do improve following surgery, albeit to a lesser magnitude than non-mental disorder patients, and ultimately have lower postoperative scores at their final follow. As with most orthopaedic surgery literature, the investigation of mental health and hip preservation is primarily via retrospective level four evidence with small numbers of patients from a single centre and single surgeon at short-term follow-up. Although hip preservation surgeons are orthopaedic surgeons by training and practice, they must be able to recognize mental wellness disorders and either treat or refer when suspected or identified.

Progression of Osteoarthritis at Long-term Follow-up in Patients Treated for Symptomatic Femoroacetabular Impingement With Hip Arthroscopy Compared With Nonsurgically Treated Patients

BACKGROUND

Femoroacetabular impingement (FAI) is a common cause of hip pain, especially in young patients. When left untreated, it has been demonstrated to be a risk factor for the onset or progression of osteoarthritis (OA) and has been identified as one of the main contributors leading to the need for total hip arthroplasty (THA) at a young age. While the short-term therapeutic potential of hip arthroscopy is widely recognized, little is known regarding its potential mid- to long-term preventive effect on the progression of hip OA.

PURPOSE

To (1) report clinical outcomes of arthroscopically treated FAI syndrome with a minimum 5-year follow-up and compare the results to a cohort with FAI treated nonsurgically and (2) determine the influence of hip arthroscopy on the onset and progression of hip OA in patients diagnosed with FAI.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients who had hip pain and were diagnosed with FAI were included. Exclusion criteria were (1) previous or concomitant hip surgery, (2) <5 years of follow-up, and (3) insufficient radiographs. Patients treated with hip arthroscopy were compared with a cohort of patients with FAI who were treated nonsurgically. Kaplan-Meier estimates of failure (defined as conversion to THA) were performed. Bivariate analysis and Cox regression were used to identify factors associated with inferior clinical and radiographic outcomes.

RESULTS

A total of 957 patients (650 female, 307 male; 1114 hips) (mean age, 28.03 ± 8.9 years [range, 6.5-41.0 years]) with FAI were included. A total of 132 hips underwent hip arthroscopy and 982 hips were nonoperatively treated. The mean follow-up was 12.5 ± 4.7 years (range, 5.0-23.4 years). At the final follow-up, the rate of OA progression was 26.5% in the operative group and 35.2% in the nonoperative cohort (P < .01). Conversion to THA was performed in 6.8% of the surgical patients and 10.5% of the initially nonsurgical patients (P = .19). Additionally, there was no significant difference in the risk of failure between the operatively and nonoperatively treated patients. Male sex, increased age at initial diagnosis, presence of cam morphology, and increased initial Tönnis grade were risk factors for failure (male sex: hazard ratio [HR], 2.3; P < .01; per year of increased age: HR, 1.1; P < .01; presence of cam: HR, 3.5; P < .01; per Tönnis grade: HR, 4.0; P < .01).

CONCLUSION

At a mean follow-up of nearly 13 years, 7% of patients of the surgical group experienced progression to THA, compared with 11% of the nonoperative control group. While most of the operative group showed little to no OA at final follow-up, moderate OA (Tönnis grade 2) was present in 12% of the cohort compared with 22% of nonsurgical patients. Increased age at diagnosis, male sex, presence of a cam morphology, and presence of initial arthritic joint changes were found to be risk factors for failure. The results of this study demonstrated evidence for a preventive effect of hip arthroscopy on the development and progression of OA in young patients with FAI at mid- to long-term follow-up.

Automated measurement of alpha angle on 3D-magnetic resonance imaging in femoroacetabular impingement hips: a pilot study

BACKGROUND

Femoroacetabular impingement (FAI) syndrome is an established pre-osteoarthritic condition. Diagnosis is based on both clinical and radiographic parameters. An abnormal manually calculated alpha angle in magnetic resonance imaging (MRI) is traditionally utilized to diagnose abnormal femoral head-neck offset. This pilot study aimed to assess the feasibility of automated alpha angle measurements in patients with FAI syndrome, and to compare automated with manual measurements data with regard to the time and effort needed in each method.

METHODS

Alpha angles were measured with manual and automated techniques, using postprocessing software in nineteen hip MRIs of FAI syndrome patients. Two observers conducted manual measurements. Intra- and inter-observer reproducibility and correlation of manual and automated alpha angle measurements were calculated using intra-class correlation (ICC) analysis. Both techniques were compared regarding the time taken (in minutes) and effort required, measured as the amount of mouse button presses performed.

RESULTS

The first observer's intra-observer reproducibility was good (ICC 0.77; p < 0.001) while the second observer's was good-to-excellent (ICC 0.93; p < 0.001). Inter-observer reproducibility between both observers in the first (ICC 0.45; p < 0.001) and second (ICC 0.56; p < 0.001) manual alpha angle assessment was moderate. The intra-class correlation coefficients between manual and automated alpha angle measurements were ICC = 0.24 (p = 0.052; observer 1, 1st measurement), ICC = 0.32 (p = 0.015; observer 1, 2nd measurement), ICC = 0.50 (p < 0.001; observer 2, 1st measurement), and ICC = 0.45 (p < 0.001; observer 2, 2nd measurement). Average runtime for automatic processing of the image data for the automated assessment was 16.6 ± 1.9 min. Automatic alpha angle measurements took longer (time difference: 14.6 ± 3.9 min; p < 0.001) but required less effort (difference in button presses: 231 ± 23; p < 0.001). While the automatic processing is running, the user can perform other tasks.

CONCLUSIONS

This pilot study demonstrates that objective and reliable automated alpha angle measurement of MRIs in FAI syndrome hips is feasible. Trial registration The Ethics Committee of the University of Düsseldorf approved our study (Registry-ID: 2017084398).

Benefits of a Specific and Supervised Rehabilitation Program in Femoroacetabular Impingement Patients Undergoing Hip Arthroscopy: A Randomized Control Trial

(1) To assess the efficacy of a specific rehabilitation protocol for femoroacetabular impingement syndrome (FAIS), patients who underwent hip arthroscopy (HA) were compared with a control group. (2) Patients with symptomatic FAIS who were scheduled for HA were randomized either to a control group (n = 45, 66.6% men, 41.8 ± 12.4 years) following a general post-surgical treatment protocol or to an experimental group (n = 45, 71.2% men, 40.9 ± 7.6 years) following a specific rehabilitation protocol supervised by a physiotherapist. Range of motion (ROM), orthopedic tests and pain were assessed immediately before surgery and at 4 and 14 weeks after surgery. The hip functional status was assessed by the modified Harris Hip Score (mHHS) before surgery and at the end of follow-up. (3) At 14 weeks after surgery and compared with the control group, the experimental group showed a lower percentage of positives for hip provocation tests (15.6% vs. 46.6% on Faber test; 15.6% vs. 77.8% on Fadir test; 2.2% vs. 20% on Ober test, experimental vs. control group, p < 0.001), a greater improvement in mHHS (27.2 vs. 10.7 points, p < 0.001) and higher ROM for all the movements evaluated: flexion (99.6 ± 12.2 vs. 89.6 ± 4.5, p < 0.001), extension (20.6 ± 5.8 vs. 13.3 ± 2.6, p < 0.001), adduction (30.6 ± 5.7 vs. 23.4 ± 8.4, p < 0.001), abduction (43.4 ± 10.7 vs. 32.8 ± 8.4, p < 0.001) and both internal (28.2 ± 8.5 vs. 18.7 ± 6.1, p < 0.001) and external hip rotation (36.8 ± 9.3 vs. 27.4 ± 5.6. p < 0.001). The pain decreased after surgery for both groups, although the reduction was greater in the experimental group at the end of intervention (13.8 ± 16.1 vs. 34.9 ± 16.3 mm, experimental vs. control group, p < 0.001). (4) The specific and supervised rehabilitation program in patients with FAIS undergoing HA showed better benefits at 14 weeks of treatment than the benefits achieved by a care protocol in terms of pain reduction and recovery of hip motion.

The Readability of Online Educational Materials for Femoroacetabular Impingement Syndrome

Level III.

Risk of Conversion to Arthroplasty After Hip Arthroscopy: Validation of a Published Risk Score Using an Independent, Prospectively Collected Database

BACKGROUND

Hip arthroscopy is rapidly advancing and increasingly commonly performed. The most common surgery after arthroscopy is total hip arthroplasty (THA), which unfortunately occurs within 2 years of arthroscopy in up to 10% of patients. Predictive models for conversion to THA, such as that proposed by Redmond et al, have potentially substantial value in perioperative counseling and decreasing early arthroscopy failures; however, these models need to be externally validated to demonstrate broad applicability.

PURPOSE

To utilize an independent, prospectively collected database to externally validate a previously published risk calculator by determining its accuracy in predicting conversion of hip arthroscopy to THA at a minimum 2-year follow-up.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 1.

METHODS

Hip arthroscopies performed at a single center between November 2015 and March 2017 were reviewed. Patients were assessed pre- and intraoperatively for components of the THA risk score studied-namely, age, modified Harris Hip Score, lateral center-edge angle, revision procedure, femoral version, and femoral and acetabular Outerbridge scores-and followed for a minimum of 2 years. Conversion to THA was determined along with the risk score's receiver operating characteristic (ROC) curve and Brier score calibration characteristics.

RESULTS

A total of 187 patients (43 men, 144 women, mean age, 36.0 ± 12.4 years) underwent hip arthroscopy and were followed for a mean of 2.9 ± 0.85 years (range, 2.0-5.5 years), with 13 patients (7%) converting to THA at a mean of 1.6 ± 0.9 years. Patients who converted to THA had a mean predicted arthroplasty risk of 22.6% ± 12.0%, compared with patients who remained arthroplasty-free with a predicted risk of 4.6% ± 5.3% (P < .01). The Brier score for the calculator was 0.04 (P = .53), which was not statistically different from ideal calibration, and the calculator demonstrated a satisfactory area under the curve of 0.894 (P < .001).

CONCLUSION

This external validation study supported our hypothesis in that the THA risk score described by Redmond et al was found to accurately predict which patients undergoing hip arthroscopy were at risk for converting to subsequent arthroplasty, with satisfactory discriminatory, ROC curve, and Brier score calibration characteristics. These findings are important in that they provide surgeons with validated tools to identify the patients at greatest risk for failure after hip arthroscopy and assist in perioperative counseling and decision making.

An Updated Description of More Than 5,000 Procedures from the Danish Hip Arthroscopy Registry

BACKGROUND

The Danish Hip Arthroscopy Registry (DHAR) started as a web-based prospective registry in 2012. The aim of this study was to evaluate and report epidemiologic and perioperative data from 5,333 procedures and to describe the development of the DHAR.

METHODS

The DHAR collects data from patients prospectively at the time of inclusion (preoperative evaluation) and at 1, 2, 5, and 10 years after arthroscopic hip surgery. The surgeon reports surgical data at the time of surgery. The DHAR uses a number of validated patient-related outcome measures (PROMs): the Copenhagen Hip and Groin Outcome Score (HAGOS), Hip Sports Activity Scale (HSAS), EuroQol 5 Dimensions (EQ-5D), and a numeric rating scale for pain (NRS pain).

RESULTS

Of the 5,333 procedures, 58% were done in female patients. The mean age was 37.7 years. The mean duration of surgery was 78 minutes, and the mean duration of traction was 45 minutes. Combined cam and pincer resections were performed in 64% of the patients, and labral repair was done in 82%. The most common type of acetabular chondral damage found was Beck grade-2 lesions (43%). Grade-3 and 4 changes were seen in 29% and 11% of the patients, respectively. The 1-year HAGOS PROM values increased to a median of 69.1 (interquartile range [IQR], 68.2 to 70.0) for pain, 64.9 (IQR, 64.0 to 65.7) for symptoms, 71.3 (IQR, 70.3 to 72.3) for activities of daily living, 56.2 (IQR, 55.1 to 57.4) for sports, 42.2 (IQR, 40.8 to 43.5) for physical activity, and 50.7 (IQR, 49.7 to 51.8) for quality of life, and the 1-year EQ-5D increased to a median of 0.75 (IQR, 0.74 to 0.76). Five-year outcomes for 383 patients showed a significant increase in all PROMs (p < 0.05).

CONCLUSIONS

Patients referred for hip arthroscopy reported pain, functional disabilities, and a decreased activity level and quality of life prior to surgery but demonstrated improvements after 1 and 5 years. The problems with developing and maintaining a large clinical registry are described. The development of a national clinical registry for hip arthroscopy was considered successful.

LEVEL OF EVIDENCE

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

Functional Outcomes of Arthroscopic Treatment in Femoroacetabular Impingement in Patients over 60 Years Old Compared with Patients Aged 40 Years or Younger

Objective  To evaluate the functional outcomes of patients diagnosed with femoroacetabular impingement (FAI) older than 60 years, compared with those of patients of age 40 years or younger.

Methods  This was a retrospective review of patients with FAI who underwent hip arthroscopy between 2010 and 2015. The patients were adults aged over 60 years with Tönnis ≤ 1 matched in a 1:1 ratio with adults aged 40 years or younger, according to the type of deformity (cam, pincer, or mixed), sex, and the date when the surgery was performed.

Results  Thirty-four patients were included in each group. The mean age was 30.6 ± 6.9 years and 65.6 ± 4.6 years in the control and case groups, respectively. There were no significant differences between the groups at 1-year follow-up ( p  > 0.05). In the group with older patients (case group), we observed a change in the total Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score from 46.3 to 22.0 in the 1 ^st postoperative year, while the control cases improved in the WOMAC score from 38.1 to 7.2 in relation to the preoperative stage.

Conclusion  In the group of patients ≤ 40 years old, a considerable change was observed in the WOMAC score without a statistical significance compared with the > 60 years group. This observation suggests that hip arthroscopy is beneficial when there is an appropriate selection of patients with FAI, regardless the age of the patient.

Editorial Commentary: The Wild, Wild West of Hip Arthroscopy-When to Pull the Trigger?

In our continued effort to refine the treatment algorithm of femoroacetabular impingement syndrome, duration of symptoms before surgery is receiving considerable attention by researchers. A (somewhat) negative linear correlation is being elucidated between outcomes and extent of damage at time of arthroscopy. Knowing this, it may be prudent in certain patient populations to recommend surgery earlier in the disease process in hopes of minimizing the amount of damage to the joint to delay or avoid the onset of arthritis.

Evaluation of Statistical Shape Modeling in Quantifying Femoral Morphologic Differences Between Symptomatic and Nonsymptomatic Hips in Patients with Unilateral Femoroacetabular Impingement Syndrome

Purpose

To determine whether statistical shape modeling can detect subtle morphologic differences in the shape of the proximal femur that correlate with clinical findings of unilateral femoroacetabular impingement syndrome.

Methods

Patients who had diagnoses of unilateral femoroacetabular impingement syndrome and who had existing computed tomography scans of their pelvises were included. Three-dimensional shape models in the form of triangle meshes were generated from the computed tomography images. Statistical shapes of cam-type and normal hips were compared to identify structural differences.

Results

The study included 33 hips in 17 subjects. Of the subjects, 7 (41.1%) were male, and 10 (58.9%) were female. The subjects ranged in age from 17-60 years of age (mean 36.3 ± 11.0 years old). The statistical shape modeling found mean shapes and modes after optimizing the groupwise correspondence. Symptomatic hips demonstrated 1 mm of thickening as compared to the femoral necks of asymptomatic hips, corresponding to cam lesions.

Conclusions

Symptomatic cam deformities were an average of 1 mm more prominent in the femoral neck region as compared to the asymptomatic hips when using statistical shape modeling. The present study provides a proof of the concept that statistical shape modeling can be used to examine and help define cam morphology and that subtle morphologic differences may account for developing femoroacetabular impingement syndrome.

Clinical Relevance

Using the methods presented in this study, it would be possible to define cam and pincer morphologies by creating statistical shape models, and this work could potentially lead to the development of a new classification system for femoroacetabular impingement syndrome lesions.

Prevalence of Femoroacetabular Impingement Syndrome among Young and Middle-aged White Adults

Objective.

The purpose of the study was to determine the prevalence of femoroacetabular impingement syndrome (FAIS) in white adults 20 to 49 years of age.

Methods.

Participants were white men and women aged 20–49 years, recruited through random digit dialing from the population of Metro Vancouver, British Columbia, Canada. Participants filled out a self-administered questionnaire and underwent a physical examination and radiographs of both hips. FAIS was defined as a combination of hip symptoms, physical signs of impingement, and radiological findings of cam or pincer morphology as recommended by the Warwick Agreement. All analyses were weighted to reflect the population from which the sample was drawn.

Results.

Data were obtained for 500 participants. In the study population, 48.9% were males and the age distribution was 32.2%, 31.4%, and 36.4% in the groups 20–29, 30–39, and 40–49 years, respectively. The physical signs of impingement correlated significantly with symptoms, but there was no significant association between either symptoms or physical examination with radiographic findings. FAIS on either side was found in 3.0% (95% CI 1.5–4.5) of the population.

Conclusion.

In this study, FAIS was present in 3% of whites aged 20–49 years. Further research is needed to develop consistent criteria for assessing hip symptoms, physical signs, and hip joint morphology, and to better understand the relationships between them.

Interobserver and intraobserver reliability of a new radiological classification for femoroacetabular impingement syndrome

PURPOSE

Radiological evaluation of femoroacetabular impingement is based on single-plane parameters such as the alpha angle or the center edge angle, or complex software reconstruction. A new simple classification for cam and pincer morphologies, based on a two-plane radiological evaluation, is presented in this study. The determination of the intraobserver and interobserver reliability of this new classification is the purpose of this study.

METHODS

We retrospectively reviewed the three-view hip study in patient undergoing hip arthroscopy for FAI syndrome between October 2015 and April 2016. Any case having protrusio acetabuli, coxa profunda or which has undergone previous osteotomic surgery was excluded. Five observers used our proposed classification to identify three different stages for the cam and pincer morphologies. Inter- and intraobserver agreement of classification was determined using average pairwise Cohen's kappa coefficient.

RESULTS

The interobserver agreement for the pincer and cam morphologies was excellent. For the pincer morphology classification, the average Kappa agreement was 0.838 (range 0.764-0.944). For the cam morphology, the average pairwise Cohen's kappa coefficient was 0.846 (range 0.734-0.929). The intraobserver agreement was excellent as well. The average percent pairwise agreement was 0.870 and 0.845 for pincer and cam type, respectively.

CONCLUSIONS

The new classification system shows excellent levels of inter- and intraobserver agreement for both deformities. This classification is demonstrated to be a useful tool in planning hip arthroscopy. Further studies are needed to correlate the classification itself with specific intraoperative findings.

Increased pelvic mobility and altered hip muscles contraction patterns: two-year follow-up cam-FAIS corrective surgery

Femoroacetabular impingement syndrome (FAIS) surgery can produce improvements in function and patient satisfaction; however, data on muscle assessment and kinematics of high mobility tasks of post-operative patients is limited. The purpose of this study was to evaluate kinematics and muscle activity during a deep squat task, as well as muscle strength in a 2-year follow-up FAIS corrective surgery. Eleven cam morphology patients underwent motion and electromyography capture while performing a squat task prior and 2-years after osteochondroplasty and were BMI-, age- and sex-matched to 11 healthy control (CTRL) participants. Isometric muscle strength, flexibility and patient-reported outcome measures (PROMs) were also evaluated. Post-operative FAIS was significantly weaker during hip flexion (23%) and hip flexion-with-abduction (25%) movements when compared with CTRL, no improvements in squat depth were observed. However, post-operative FAIS increased the pelvic range of motion during the squat descent (P = 0.016) and ascent (P = 0.047). They had greater peak activity for the semitendinosus and total muscle activity for the gluteus medius, but decreased peak activity for the glutei and rectus femoris during squat descent; greater total muscle activity for the tensor fascia latae was observed during squat ascent (P = 0.005). Although not improving squat depth, post-operative patients increased pelvic ROM and showed positive PROMs. The muscle weakness associated with hip flexion and flexion-with-abduction observed at the follow-up can be associated with the alterations in the muscle activity and neuromuscular patterns. Rehabilitation programs should focus on increasing pelvis and hip muscles flexibility and strength.

Increased Prevalence of Femoroacetabular Impingement in Patients With Proximal Hamstring Tendon Injuries

PURPOSE

To determine the prevalence of clinically diagnosed femoroacetabular impingement (FAI) in a consecutive series of patients presenting with proximal hamstring tendon injury and to correlate this with pelvic anatomic factors.

METHODS

The prevalence of clinically symptomatic cam-, pincer-, and mixed-type and overall FAI was calculated among a consecutive series of patients presenting to a hip preservation clinic with a confirmed clinical and radiographic diagnosis of proximal hamstring tendon injury between 2012 and 2017. The presence of a cam lesion was determined by an alpha angle > 50° on radiographs and computed tomography radial sequences of the head-neck junction and a femoral head-neck offset ratio < 0.18. Clinical diagnoses of osseous impingement were determined according to accepted pathomorphologic signs and measurements. A diagnosis of FAI was confirmed by imaging findings of acetabular overcoverage for pincer-type FAI and the presence of an anterior or lateral cam lesion for cam-type FAI.

RESULTS

Overall, 120 hips in 97 patients (mean age, 45 years) were included in this study. A clinical diagnosis of FAI was noted in 70.8% of hips (pincer-type 9.2%, cam-type 40.8%, mixed-type 20.8%), an approximate 2- to 7-fold increased prevalence in comparison with the general population from prior studies.

CONCLUSIONS

The prevalence of FAI is high in patients with symptomatic proximal hamstring tendon pathology. Because FAI results in restriction of hip range of motion and altered pelvic tilt, future studies are warranted to investigate whether the presence of FAI acts as a predisposing factor for injury to the hamstring muscle complex.

LEVEL OF EVIDENCE

Level IV, case series.

3D-MRI versus 3D-CT in the evaluation of osseous anatomy in femoroacetabular impingement using Dixon 3D FLASH sequence

OBJECTIVE

To determine if hip 3D-MR imaging can be used to accurately demonstrate femoral and acetabular morphology in the evaluation of patients with femoroacetabular impingement.

MATERIALS AND METHODS

We performed a retrospective review at our institution of 17 consecutive patients (19 hips) with suspected femoroacetabular impingement who had both 3D-CT and 3D-MRI performed of the same hip. Two fellowship-trained musculoskeletal radiologists reviewed the imaging for the presence and location of cam deformity, anterior-inferior iliac spine variant, lateral center-edge angle, and neck-shaft angle. Findings on 3D-CT were considered the reference standard. The amount of radiation that was spared following introduction of 3D-MRI was also assessed.

RESULTS

All 17 patients suspected of FAI had evidence for cam deformity on 3D-CT. There was 100% agreement for diagnosis (19 out of 19) and location (19 out of 19) of cam deformity when comparing 3D-MRI with 3D-CT. There were 3 type I and 16 type II anterior-inferior iliac spine variants on 3D-CT imaging with 89.5% (17 out of 19) agreement for the anterior-inferior iliac spine characterization between 3D-MRI and 3D-CT. There was 64.7% agreement when comparing the neck-shaft angle (11 out of 17) and LCEA (11 out of 17) measurements. The use of 3D-MRI spared each patient an average radiation effective dose of 3.09 mSV for a total reduction of 479 mSV over a 4-year period.

CONCLUSION

3D-MR imaging can be used to accurately diagnose and quantify the typical osseous pathological condition in femoroacetabular impingement and has the potential to eliminate the need for 3D-CT imaging and its associated radiation exposure, and the cost for this predominantly young group of patients.

Relationship Between Hip Morphology and Hip-Related Patient-Reported Outcomes in Young and Middle-Aged Individuals: A Population-Based Study

Objective

Radiographic measurements of the alpha angle and the lateral center edge (LCE) angle in the hip joint are important for the diagnosis of femoroacetabular syndrome, a potential risk factor for hip osteoarthritis. Our objective was to determine whether these measurements are associated with hip‐related patient‐reported outcomes in young and middle‐aged individuals.

Methods

A stratified random sample of white men and women ages 20–49 years, with and without hip pain, was selected using random digit dialing from the population of metro Vancouver, Canada. The alpha and LCE angles were measured bilaterally on radiographs using Dunn and anteroposterior views, respectively. Patient‐reported outcomes were measured by the Copenhagen Hip And Groin Outcome Score (HAGOS), which has scales for symptoms, pain, daily activities, sports, physical activity, and quality of life (QoL). We performed descriptive analyses and a regression analysis with restricted cubic splines, adjusted for age and sex and weighted for the sampling design.

Results

Data were obtained for 500 subjects. The alpha angle distribution was strongly skewed, with a mean of 54°. The LCE angle distribution was symmetric, with a mean of 34°. In the restricted cubic splines analysis, the relationship between the alpha angle and HAGOS scores was nonlinear, with higher alpha angles generally associated with worse HAGOS scores for alpha >60°. The associations were statistically significant for symptoms, sports, and QoL. No association was found between the LCE angle and HAGOS scales.

Conclusion

In a general population sample ages 20–49 years, we have found an association between the alpha angle and hip‐related patient‐reported outcomes.

Acetabular labral tear description and measures of pincer and cam-type femoroacetabular impingement and interobserver variability on 3 T MR arthrograms

PURPOSE

To evaluate the inter-rater agreement for description of labral tears and measures of femoroacetabular impingement (FAI) on 3 T hip MR arthrography.

MATERIALS AND METHODS

53 hip MR arthrograms were reviewed by three musculoskeletal radiologists. Labral tears were described (Czerny classification) with extents recorded. Cam- and pincer-type FAI measures were performed. Intraclass correlation (ICC) and kappa statistic (κ) assessed inter-observer agreement.

RESULTS

There was fair agreement for labral tear description (κ = 0.25-0.39) and for alpha angles (ICC = 0.54), and fair to excellent agreement for other measures of FAI (ICC = 0.51-0.90).

CONCLUSION

There is moderate inter-observer variability reporting labral tears and measures of FAI.

T2*-Mapping of Acetabular Cartilage in Patients With Femoroacetabular Impingement at 3 Tesla: Comparative Analysis with Arthroscopic Findings

Objective To evaluate the diagnostic accuracy of T2*-mapping for detecting acetabular cartilage damage in patients with symptomatic femoroacetabular impingement (FAI). Design A total of 29 patients (17 females, 12 males, mean age 35.6 ± 12.8 years, mean body mass index 25.1 ± 4.1 kg/m², 16 right hips) with symptomatic FAI underwent T2* MRI and subsequent hip arthroscopy. T2* values were obtained by region of interest analysis in seven radially reformatted planes around the femoral neck (anterior, anterior-superior, superior-anterior, superior, superior-posterior, posterior-superior, posterior). Intraoperatively, a modified Outerbridge classification was used for assessment of the cartilage status in each region. T2* values and intraoperative data were compared, and sensitivity, specificity, negative predictive values (NPV) and positive predictive values (PPV) as well as the correlation between T2*-mapping and intraoperative findings, were determined. The mean time interval between MRI and arthroscopy was 65.7 ± 48.0 days. Results Significantly higher T2* values were noted in arthroscopically normal evaluated cartilage than in regions with cartilage degeneration (mean T2* 25.6 ± 4.7 ms vs. 19.9 ± 4.5 ms; P < 0.001). With the intraoperative findings as a reference, sensitivity, specificity, NPV and PPV were 83.5%, 67.7%, 78.4% and 74.4%, respectively. The correlation between T2*-mapping and intraoperative cartilage status was moderate (ρ = -0.557; P < 0.001). Conclusions T2*-mapping enabled analysis of acetabular cartilage with appropriate correlation with intraoperative findings and promising results for sensitivity, specificity, PPV, and NPV in this cohort. Our results emphasize the value of T2*-mapping for the diagnosis of hip joint cartilage pathologies in symptomatic FAI.

Prevalence of Cam Deformity with Associated Femoroacetabular Impingement Syndrome in Hip Joint Computed Tomography of Asymptomatic Adults

Purpose

Femoroacetabular impingement (FAI) is considered an important cause of early degenerative arthritis development. Although three-dimensional (3D) imaging such as computed tomography (CT) and magnetic resonance imaging are considered precise imaging modalities for 3D morphology of FAI, they are associated with several limitations when used in out-patient clinics. The paucity of FAI morphologic data in Koreans makes it difficult to select the most effective radiographical method when screening for general orthopedic problems. We postulate that there might be an individual variation in the distribution of cam deformity in the asymptomatic Korean population.

Materials and Methods

From January 2011 to December 2015, CT images of the hips of 100 subjects without any history of hip joint ailments were evaluated. A computer program which generates 3D models from CT scans was used to provide sectional images which cross the central axis of the femoral head and neck. Alpha angles were measured in each sectional images. Alpha angles above 55° were regarded as cam deformity.

Results

The mean alpha angle was 43.5°, range 34.7–56.1°(3 o'clock); 51.24°, range 39.5–58.8°(2 o'clock); 52.45°, range 43.3–65.5°(1 o'clock); 44.09°, range 36.8–49.8°(12 o'clock); 40.71, range 33.5–45.8°(11 o'clock); and 39.21°, range 34.1–44.6°(10 o'clock). Alpha angle in 1 and 2 o'clock was significantly larger than other locations (P<0.01). The prevalence of cam deformity was 18.0% and 19.0% in 1 and 2 o'clock, respectively.

Conclusion

Cam deformity of FAI was observed in 31% of asymptomatic hips. The most common region of cam deformity was antero-superior area of femoral head-neck junction (1 and 2 o'clock).

Relationship between physical activity and hip pain in persons with and without cam or pincer morphology: a population-based case-control study

OBJECTIVES

The purpose of the study was to determine if physical activity (PA) is a risk factor for persistent or recurrent hip pain in young and middle-aged persons with and without radiographic findings of cam or pincer morphology (CPM).

METHODS

A population sample of persons aged 20-49 with (cases) and without (controls) hip pain in Metro Vancouver, Canada, was selected through random digit dialing (RDD). Self-reported PA was expressed as average energy expenditure (MET-hours) per year, over lifetime. CPM was defined as alpha angle >55°, lateral centre edge angle (LCE) >40°, or positive cross-over sign.

RESULTS

Data were obtained for 500 subjects, 269 cases and 231 controls. Prevalence of radiographic CPM was 49% in the cases and 44% in the controls. In a logistic regression model adjusted for age, gender and CPM, total lifetime PA, including occupational, domestic and recreational activities, was significantly associated with hip pain (Odds ratio (OR) 1.30 per 1000 MET-hours, 95% CI 1.15-1.38). The effect of total PA was observed in those with CPM (1.44, 1.17-1.78) and without CPM (1.23, 1.04-1.45). For domestic activities, the association was seen only in those with CPM (significant interaction). When PA was categorized into quartiles, higher levels of PA were associated with a greater risk of pain.

CONCLUSIONS

PA, as measured by average energy expenditure over lifetime is a risk factor for hip pain in young and middle-aged persons. For some activities, the risk is likely increased in persons with radiographic evidence of CPM.

Hip Pain and Mobility Deficits-Hip Osteoarthritis: Revision 2017

The Orthopaedic Section of the American Physical Therapy Association (APTA) has an ongoing effort to create evidence-based practice guidelines for orthopaedic physical therapy management of patients with musculoskeletal impairments described in the World Health Organization's International Classification of Functioning, Disability, and Health (ICF). The purpose of these revised clinical practice guidelines is to review recent peer-reviewed literature and make recommendations related to hip pain and mobility deficits. J Orthop Sports Phys Ther. 2017;47(6):A1-A37. doi:10.2519/jospt.2017.0301.

Both 3-T dGEMRIC and Acetabular-Femoral T2 Difference May Detect Cartilage Damage at the Chondrolabral Junction

BACKGROUND

In addition to case reports of gadolinium-related toxicities, there are increasing theoretical concerns about the use of gadolinium for MR imaging. As a result, there is increasing interest in noncontrast imaging techniques for biochemical cartilage assessment. Among them, T2 mapping holds promise because of its simplicity, but its biophysical interpretation has been controversial.

QUESTIONS/PURPOSES

We sought to determine whether (1) 3-T delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) and T2 mapping are both capable of detecting cartilage damage at the chondrolabral junction in patients with femoroacetabular impingement (FAI); and (2) whether there is a correlation between these two techniques for acetabular and femoral head cartilage assessment.

METHODS

Thirty-one patients with hip-related symptoms resulting from FAI underwent a preoperative 3-T MRI of their hip that included dGEMRIC and T2 mapping (symptomatic group, 16 women, 15 men; mean age, 27 ± 8 years). Ten volunteers with no symptoms according to the WOMAC served as a control (asymptomatic group, seven women, three men; mean age, 28 ± 3 years). After morphologic cartilage assessment, acetabular and femoral head cartilages were graded according to the modified Outerbridge grading criteria. In the midsagittal plane, single-observer analyses of precontrast T1 values (volunteers), the dGEMRIC index (T1_Gd, patients), and T2 mapping values (everyone) were compared in acetabular and corresponding femoral head cartilage at the chondrolabral junction of each hip by region-of-interest analysis.

RESULTS

In the symptomatic group, T1_Gd and T2 values were lower in the acetabular cartilage compared with corresponding femoral head cartilage (T1_Gd: 515 ± 165 ms versus 650 ± 191 ms, p < 0.001; T2: 39 ± 8 ms versus 46 ± 10 ms, p < 0.001). In contrast, the asymptomatic group demonstrated no differences in T1 and T2 values for the acetabular and femoral cartilages with the numbers available (T1: 861 ± 130 ms versus 860 ± 182 ms, p = 0.98; T2: 43 ± 7 ms versus 42 ± 6 ms, p = 0.73). No correlation with the numbers available was noted between the modified Outerbridge grade and T1, T1_Gd, or T2 as well as between T2 and either T1 or T1_Gd.

CONCLUSIONS

Without the need for contrast media application, T2 mapping may be a viable alternative to dGEMRIC when assessing hip cartilage at the chondrolabral junction. However, acquisition-related phenomena as well as regional variations in the microstructure of hip cartilage necessitate an internal femoral head cartilage control when interpreting these results.

LEVEL OF EVIDENCE

Level IV, diagnostic study.

Can hip arthroscopy in the presence of arthritis delay the need for hip arthroplasty?

Hip arthroscopy for joint preservation surgery has grown immensely over the last two decades. There is now an increasing trend to try and expand the role of hip arthroscopy to include patients of an older age or perhaps even with signs of arthritis, instead of the established patient group of young adults with mechanical symptoms or serious athletes. But how much of this growth is really justified? Once arthritis is apparent, the arthroscopic procedures needed to try and limit progression of the disease are likely to be different to those needed in young adult non-arthritic hips. Similarly, the expectation of results following an arthroscopic procedure in an older adult with arthritis must also be different. With an almost 5-fold increase in conversion rate from arthroscopy to arthroplasty in the over 50s population, arthroscopy in arthritis is a different procedure, with a different outcome, to arthroscopy in young adults with no evidence of osteoarthritis. This article takes a closer inspection at outcomes following hip arthroscopy in the older population particularly in those with evidence of early arthritis. This paper does not attempt to make recommendations in other diagnoses such as inflammatory arthritis or other secondary arthritides. It must be considered that hip arthroscopy is not a benign intervention: as well as the surgical risks, the lengthy rehabilitation period should be factored into the equation. Although the nature of surgeons is to find new techniques and push boundaries, we highlight the need for caution in undertaking arthroscopic intervention when arthritis is already apparent at presentation.

A Qualitative Assessment of Return to Sport After Hip Arthroscopy for Femoroacetabular Impingement

BACKGROUND

Hip arthroscopy for femoroacetabular impingement (FAI) is known to produce excellent outcomes, yet some patients do not return to their preinjury level of sport participation. Much literature on return to sport has revolved around anterior cruciate ligament reconstruction and even shoulder instability, but none to date have used qualitative, semistructured patient interviews on patients with hip labral tears.

PURPOSE

To understand the factors influencing the decision to return to sport after arthroscopic hip surgery for FAI.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

An experienced interviewer conducted qualitative, semistructured interviews of patients aged 18 to 60 years who had arthroscopic hip surgery for FAI. All had preinjury participation in sport and a minimum 2-year follow-up with no revision surgery. Qualitative analysis was then performed to derive codes, categories, and themes. An assessment of preinjury and current sports participation by type, level of competition, and frequency along with patient-reported hip function was also obtained. In addition, current modified Harris Hip Score (mHHS), international Hip Outcome Tool (iHOT-12), Hip Outcome Score-sports-specific subscale (HOS-SSS), and a coping mechanism evaluation (Brief COPE) were also recorded.

RESULTS

A total of 23 patients were interviewed to reveal the overarching themes of internal motivation, external encouragement, and resetting expectations as the predominant factors influencing a patient's decision to return to preinjury sport. Subjective outcome measurements (mHHS, iHOT-12, patient satisfaction) showed significant differences between patients who did and did not return to sport. Interestingly, the adaptive and maladaptive coping mechanisms matched and supported our themes in those patients who described fear and self-motivation as defining features influencing their cessation of or return to play, respectively.

CONCLUSION

Self-motivation, aging, pain, encouragement from others, and adapting to physical limitations can largely affect a patient's decision to return to sport after arthroscopic hip surgery for FAI. Innate coping mechanisms may also help to predict the course of and subsequently aid in a patient's postoperative recovery.

Prospective 12-month functional and vocational outcomes of hip arthroscopy for femoroacetabular impingement as part of an evidence-based hip pain rehabilitation pathway in an active military population

Background

Femoroacetabular impingement (FAI) is common with an estimated prevalence of 10–15% among young active individuals. The natural history of the disorder is progression to early osteoarthritis. Hip arthroscopy is recommended if conservative treatments fail; however, outcomes are unclear, particularly in highly active populations.

Aim

To evaluate the functional and vocational outcome of hip arthroscopy, as part of an evidence-based rehabilitation hip pain pathway, for the treatment of FAI in an active military population.

Methods

All patients in the defence rehabilitation hip pain pathway, with a confirmed diagnosis of FAI who failed conservative treatment, were assessed prior to surgery and at 2, 6 and 12 months postsurgery. Outcome measures included the Visual Analogue Scale (VAS) for hip pain, Non-Arthritic Hip Score (NAHS) for function, and vocational assessments including functional activity assessment (FAA) and Joint Medical Employment Standard for military employability and deployability.

Results

101 patients completed the study (mean age=33 years) (male:female:75:26) (Royal Navy/British Army/Royal Air Force: 13%/48%/39%). Outcomes demonstrated significant improvements with large effect size. Preoperative NAHS mean=62.9 (SD 16.4), 12-month postoperative NAHS mean=78.8 (18.3), mean improvement in NAHS=15.9 (95% CI 12.3 to 19.5, p<0.001). Preoperative VAS pain mean=51.3 (20.9), 12-month postoperative VAS pain=25.6 (24.5). Mean improvement 25.7 (95% CI 19.4 to 31.99, p<0.001). 73% of patients had a deployable medical category at 12 months postoperative.

Conclusions

These data confirm that hip arthroscopy as part of a structured evidence-based multidisciplinary care pathway produces significant and continued symptomatic, functional and vocational improvements over a 12-month period in a military population exposed to high intensity, weight-bearing exercise in uncontrolled and unforgiving environments.

Histology of damaged acetabular cartilage in symptomatic femoroacetabular impingement: an observational analysis

This prospective study on symptomatic adult patients with femoroacetabular impingement (FAI) who underwent open surgical intervention for management was designed to identify any obvious histological differences in the damaged acetabular cartilage within different subgroups of FAI. 20 patients underwent surgical intervention following safe surgical dislocation of the hip. There were 6 cases of cam impingement, 5 cases of pincer impingement and 9 of the mixed type. Pincer impingement cases demonstrated a characteristic focal, well-circumscribed and localized area of severe damage. On the other hand, cases with cam impingement showed a diffuse area of involvement affecting a larger surface of the acetabular cartilage, with degenerative changes, superficial erosions and some discontinuities. A small biopsy specimen of the acetabular rim including bone, cartilage and labrum from the affected zone was obtained in all cases. Histological evaluation was performed under normal and polarized light microscopy. Histological findings helped corroborate the pre-operative diagnosis and also define the unique nature of impingement and specific damage according to the type of impingement.

SURGICAL TREATMENT FOR FEMOROACETABULAR IMPINGEMENT IN A GROUP THAT PERFORMS SQUATS

Objective: Describe the results from arthroscopic surgical treatment on a group of patients who developed symptoms after repetitive physical activity of moving their hips in a position of hyperflexion, as in leg presses and squats. Methods: The study group comprised 47 individuals (48 hips) who developed the onset of painful symptoms associated with hip hyperflexion exercises (leg presses or squats) and underwent arthroscopic treatment. The patients were evaluated radiographically and clinically according to the “Harris Hip Score", as modified by Byrd (MHHS), pre and postoperatively, and were asked about their return to sports activities and the surgical findings. Results: The mean preoperative and postoperative MHHS, respectively, were 60 points (SD 11.0, range 38.5 to 92.4) and 95.9 points (SD 7.7, range 63.8 to 100), with an increase of 35.9 points (P < 0.001). Regarding physical activity, 30 individuals (71.5%) resumed sports activities after surgery, and 25 of them (83.4%) at the previous level. Six patients (12.8%) did not resume activities because of persistent pain. During arthroscopy, 48 hips (100%) presented lesions of the acetabular labrum, and 41 hips (85.4%) had acetabular chondral lesions. Conclusion: The patients with painful symptoms after hip hyperflexion exercises associated with femoroacetabular impingement presented improvements after arthroscopic treatment.

Hip arthroscopy

Hip arthroscopy is a safe method for treating a variety of pathological conditions that were unknown until a decade ago. Femoroacetabular impingement is the commonest of these pathological conditions and the one with the best results when treated early on. The instruments and surgical technique for hip arthroscopy continue to evolve. New indications for hip arthroscopy has been studied as the ligamentum teres injuries, capsular repair in instabilities, dissection of the sciatic nerve and repair of gluteal muscles tears (injuries to the hip rotator cuff), although still with debatable reproducibility. The complication rate is low, and ever-better results with fewer complications should be expected with the progression of the learning curve.

Femoroacetabular Impingement: Prevalent and Often Asymptomatic in Older Men: The Osteoporotic Fractures in Men Study

BACKGROUND

The epidemiology of femoroacetabular impingement (FAI) is important but incompletely understood, because most reports arise from symptomatic populations. Investigating the prevalence of FAI in a community-based cohort could help us better understand its epidemiology and in particular the degree to which it might or might not be associated with hip pain.

QUESTIONS/PURPOSES

The purposes of this study were (1) to evaluate the proportion of older (≥65 years of age) men with morphologic abnormalities consistent with FAI; and (2) to assess the association of the morphologic abnormalities with prevalent radiographic hip osteoarthritis (OA) and hip pain.

METHODS

Anteroposterior radiographs were obtained in 4140 subjects (mean age±SD, 77±5 years) from the Osteoporotic Fractures in Men study. We assessed each hip for cam, pincer, and mixed FAI types using validated radiographic definitions. Both intra- and interobserver reproducibility were >0.9. Radiographic hip OA was assessed by an expert reader (intraobserver reproducibility, 0.7-0.8) using validated methods, and summary grades of 2 or greater (on a scale from 0 to 4) were used to define radiographic hip OA. Covariates including hip pain in the last 30 days were collected by questionnaires that were answered by all patients included in this report. Logistic regressions with generalized estimating equations were performed to evaluate the association of radiographic features of FAI and arthrosis.

RESULTS

Pincer, cam, or mixed types of radiographic FAI had a prevalence of 57% (1748 of 3053), 29% (886 of 3053), and 14% (419 of 3053), respectively, in this group of older men. Both pincer and mixed types of FAI were associated with arthrosis but not with hip pain (odds ratio [OR], 1.63; 95% confidence interval [CI], 1.25-2.13; p<0.001 for pincer and OR, 2.49; 95% CI, 1.65-3.76; p<0.001 for mixed type). Patients with hips characterized by cam-type FAI had slightly reduced hip pain without the presence of arthrosis compared with hips without FAI (OR, 0.82; 95% CI, 0.68-0.99; p=0.037). A center-edge angle>39° and a caput-collum-diaphyseal angle<125° were associated with arthrosis (OR, 1.53; 95% CI, 1.22-1.94; p<0.001 and OR, 2.09; 95% CI, 1.24-3.51; p=0.006, respectively), but not with hip pain (OR, 0.89; 95% CI, 0.77-1.03; p<0.108 and OR, 0.99; 95% CI, 0.67-1.45; p=0.945, respectively). An impingement angle<70° was associated with less hip pain compared with hips with an impingement angle≥70° (OR, 0.76; 95% CI, 0.61-0.95; p=0.015).

CONCLUSIONS

FAI is common in older men and represents more of an anatomic variant rather than a symptomatic disease. This finding should raise questions on how age, activities, and this anatomic variant each contribute to result in symptomatic disease.

LEVEL OF EVIDENCE

Level III, prognostic study.

A Computed Tomography Study of Gender Differences in Acetabular Version and Morphology: Implications for Femoroacetabular Impingement

PURPOSE

To assess the prevalence of acetabular retroversion in a large population of patients with asymptomatic hips. Furthermore, we sought to identify gender differences in acetabular morphology to address the current thinking that retroversion and pincer-type femoroacetabular impingement (FAI) are more common in women.

METHODS

We retrospectively reviewed morphologic features of acetabula from a consecutive series of trauma-protocol computed tomography scans of patients without pelvis injury. An automated algorithm determined the acetabular rim profile and center of the femoral head, normalized the frontal plane of the pelvis, and calculated version and coverage. We then compared male and female rim profiles, specifically focusing on version and acetabular wall coverage in the 1-o'clock (anterosuperior), 2-o'clock (central), and 3-o'clock (inferior) positions.

RESULTS

Of 1,088 patients in the database, 878 had complete data (i.e., age, ethnicity, and body mass index) and were therefore included in the final analysis. Of these, 34.3% were women and 65.7% were men. Mean global acetabular version was 19.1° for men and 22.2° for women (P < .001). Mean acetabular version for men and women was 15.5° and 18.3°, respectively, in the 1-o'clock position; 21.5° and 24.0°, respectively, in the 2-o'clock position; and 20.2° and 24.3°, respectively, in the 3-o'clock position (P < .001 for all 3). True retroversion (<0°) was observed only in the 1-o'clock position. The prevalence of true acetabular retroversion in the 1-o'clock position for men and women was 4.3% and 3%, respectively (P = .36).

CONCLUSIONS

Mean global and focal acetabular anteversion was greater in women, and the prevalence of focal cephalad retroversion in the 1-o'clock position was not significantly different compared with men. Acetabular retroversion and anterior overcoverage are not more prevalent in women in the anterosuperior acetabulum, where femoroacetabular impingement most commonly occurs.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Possible association of single nucleotide polymorphisms in the 3' untranslated region of HOXB9 with acetabular overcoverage

OBJECTIVES

Excessive acetabular coverage is the most common cause of pincer-type femoroacetabular impingement. To date, an association between acetabular over-coverage and genetic variations has not been studied. In this study we investigated the association between single nucleotide polymorphisms (SNPs) of paralogous Homeobox (HOX)9 genes and acetabular coverage in Japanese individuals to identify a possible genetic variation associated with acetabular over-coverage.

METHODS

We investigated 19 total SNPs in the four HOX9 paralogs, then focused in detail on seven of those located in the 3' untranslated region of HOXB9 (rs8844, rs3826541, rs3826540, rs7405887, rs2303485, rs2303486, rs79931349) using a case-control association study. The seven HOXB9 SNPs were genotyped in 316 subjects who had all undergone radiological examination. The association study was performed by both single-locus and haplotype-based analyses.

RESULTS

The genotype and allele frequencies of the five HOXB9 SNPs showed significant association with acetabular over-coverage compared with controls (rs7405887 OR = 3.16, p = 5.29E-6, 95% CI 1.91 to 5.25). A significant difference was also detected when haplotypes were evaluated (OR = 2.59, p = 2.61E-5, 95% CI 1.65 to 4.08). The two HOXB9 SNPs (rs2303485, rs2303486) were associated with decreased acetabular coverage (rs2303485 OR = 0.524, p = 0.0091, 95% CI 0.322 to 0.855; rs2303486 OR = 0.519, p = 0.011, 95% CI 0.312 to 0.865).

CONCLUSIONS

The five HOXB9 SNPs (rs8844, rs3826541, rs3826540, rs7405887, rs79931349) were associated with acetabular over-coverage. On the other hand, the two SNPs (rs2303485 and rs2303486) were associated with the lower acetabular coverage. The association of rs2303486 would be consistent with the previous study. Therefore, the HOXB9 SNPs might be involved in the morphogenesis of acetabular coverage, and could be an independent risk factor for developing pincer-type femoroacetabular impingement. Cite this article: Bone Joint Res 2015;4:50-5.

Is prophylactic surgery for femoroacetabular impingement indicated? A systematic review

BACKGROUND

This is a systematic review to determine if prophylactic surgical intervention for asymptomatic patients with radiographic evidence of femoroacetabular impingement (FAI) is warranted to prevent early degenerative joint disease of the hip.

METHODS

A systematic search was performed from 1965 to 2013 in PubMed and EMBASE. Inclusion criteria were prospective or retrospective studies comparing skeletally mature asymptomatic patients with radiographic evidence of FAI treated with prophylactic hip arthroscopic surgery versus nonoperative management. A total of 840 references were identified from the searches. After detailed eligibility screening, none of the references met the eligibility criteria.

RESULTS

No trials were identified that met the criteria for inclusion in the review.

CONCLUSION

There is a lack of available evidence to support surgical intervention for the treatment of FAI in asymptomatic patients. This article attempts to address this dilemma by reviewing the available literature to answer several questions that would indirectly address the topic. First, what is the prevalence of FAI in the asymptomatic population? Second, what is the natural history of FAI if left untreated? Upon reviewing these issues, the authors' conclusion parallels that of the systematic review: Current evidence does not support prophylactic surgery for asymptomatic FAI in the vast majority of cases. However, limited evidence suggests that asymptomatic patients who have previously undergone total hip arthroplasty for FAI-induced osteoarthritis of the contralateral hip are at a significantly increased risk for early degenerative joint disease. Further research is needed to better clarify surgical indications.

Prevalence of femoro-acetabular impingement in international competitive track and field athletes

PURPOSE

The aim of our study was to analyse the prevalence of femoro-acetabular impingement (FAI) in national elite track and field athletes compared to peers using magnetic resonance imaging (MRI) and clinical examination including impingement tests.

METHODS

A total of 44 participants (22 national elite track and field athletes and 22 non-athletes) underwent an MRI for radiological findings associated with FAI, including alpha angle, lateral centre edge angle (CEA), findings of labral and cartilage lesions. The study group was furthermore investigated by the hip outcome score (HOS) and a clinical hip examination including range of motion (ROM) and impingement tests.

RESULTS

Concerning the cam impingement, there was a significant difference measured by mean alpha angle between the athlete group (52.2 ± 7.29°) and the control group (48.1 ± 5.45°, P = 0.004). Eleven athletes showed a cam impingement, while two probands of the control group had a pincer impingement and one a mixed form (P = 0.0217). There was no statistically significant difference concerning the CEA upon evaluating pincer impingement. Seven track and field athletes had a positive impingement test, whereof three had an increased alpha angle >55°. No participant of the control group showed pathological results in the impingement test (P = 0.0121).

CONCLUSIONS

MRI evidence and clinical examination suggest that cam impingement is more common in elite athletes in comparison to non-athletes. At a professional level, the intense practice of track and field athletics is susceptible for FAI.

Hip arthroscopy for femoroacetabular impingement: the changing nature and severity of associated complications over time

PURPOSE

The aim of this study was to assess complications related to arthroscopy for femoroacetabular impingement (FAI) and how these complications have changed as we have gained more experience with this procedure.

METHODS

The authors reviewed 200 hips (197 patients). The average patient age was 44.64 years and the mean follow-up time was 28.2 months. All patients underwent hip arthroscopy in the supine position. Clinically, Modified Harris Hip Scores (MHHS) and patient satisfaction with outcome were used. We divided complications into 3 groups: Group 1 related to traction, group 2 related to surgical technique or implant failure, and group 3 related to outcomes.

RESULTS

Clinically, the MHHS improved from 69.96 (±6.10) to 80.45 (±7.00), and patient satisfaction with the achieved outcome increased to 8.87 (±0.76). The overall complication rate was 15% (30 of 200 hips). Group 1 consisted of 4 patients with pudendal neuropraxia and 2 patients with ankle joint pain (P = .013). Group 2 consisted of 2 patients with lateral femoral cutaneous neuropraxia, 2 patients with iatrogenic labral perforations, one patient with a labral tear, and 4 patients with femoral head scuffs. There were 4 incidents of instrument breakage. Furthermore, 3 suture anchors failed, a second-degree burn occurred in one patient, and there was incomplete reshaping in 5 hips (P = .045). Group 3 included one patient with a snapping sound and heterotopic ossification. Second-look arthroscopy was performed for 5 hips. All the complications outlined in groups 1 and 2 are related to the learning curve and have statistical significance (P < .05).

CONCLUSIONS

Complications relating to hip arthroscopy took different forms during the early learning period, but overall complication rates decreased along the learning curve. Surgical technique-related complications such as problems with suture anchors and the reshaping of cam impingements were also considered during the later stage.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Comparative study of the femoroacetabular impingement (FAI) prevalence in male semiprofessional and amateur soccer players

INTRODUCTION

Femoroacetabular impingement (FAI) represents a novel approach to the mechanical etiology of hip osteoarthritis. The cam-type femoroacetabular impingement deformity occurs frequently in young male athletes. The aim of our study was to evaluate the prevalence of FAI in male semiprofessional soccer players using clinical examination and magnetic resonance imaging (MRI), compared to amateur soccer players. In MRI, the α angle of Nötzli is determined for quantifying FAI.

MATERIALS AND METHODS

According to power analysis, a total of 22 asymptomatic semiprofessional soccer players with a median of 23.3 years of age (range 18-30 years) and 22 male amateur soccer players with a median of 22.5 years of age (control group, range 18-29 years) underwent an MRI to measure the hip α angle of Nötzli. The α angle of the kicking legs of the semiprofessional group and the amateur group were analyzed. The study group was moreover evaluated by the Hip Outcome Score (HOS) and a clinical hip examination including range of motion (ROM) and impingement tests.

RESULTS

In the semiprofessional group, 19 soccer players had a right kicking leg and 1 soccer player had a left kicking leg. 2 soccer players kicked with two feet. In the semi-professional group, the mean value of the α angle of the kicking leg (57.3 ± 8.2°) was significantly higher than in the amateur group (51.7 ± 4.8°, P = 0.008). In the semi-professional group, 15 (62.5 %) of 24 kicking legs had an increased α angle >55°, while 5 (27.3 %) kicking legs of the amateur group had an α angle >55°. Five semi professional soccer players had findings in clinical examination, whereof 4 had an increased α angle >55°. No participant of the amateur group showed pathological results in the clinical examination (P = 0.0484). Overall, semiprofessional soccer players had a higher proportion of an increased α angle than the amateur group.

CONCLUSIONS

Semiprofessional players have a higher prevalence of an increased α angle in the kicking leg than the amateur group at the same age. The kicking leg is predisposed for FAI.

Patient satisfaction after arthroscopic repair of acetabular labral tears

Background

Acetabular labral tear is a main cause of hip pain and disability, often requiring surgical treatment. Improvements of hip arthroscopic technique have produced positive outcomes after labral repair with arthroscopy. The purpose of this study was to determine clinical outcomes and patient satisfaction after arthroscopic repair of acetabular labral tear.

Methods

We interviewed 21 patients (10 men and 11 women; mean age, 36 years [range, 22 to 57 years]) with acetabular labral tears that had been repaired arthroscopically in terms of satisfaction of the procedure. In addition, clinical outcome was assessed using visual analog scale (VAS) score, University of California, Los Angeles (UCLA) activity, Western Ontario and McMaster Universities (WOMAC) osteoarthritis index, and Harris hip score, and radiologic outcome was assessed using serial radiography. The patients were followed for 24-50 months.

Results

The mean Harris hip score was 73 points (range, 64 to 84 points) preoperatively and 83 points (range, 66 to 95 points) postoperatively. Fifteen hips (71%) were rated excellent and good. The mean WOMAC osteoarthritis index and VAS scores were improved at final follow-up. UCLA activity at the latest follow-up improved in 16 patients. The Tonnis grade of osteoarthritis at the latest follow-up did not change in all patients. Eighteen of the patients (86%) were satisfied with the procedure.

Conclusions

High rate of satisfaction after arthroscopic repair of acetabular labral tears is an encouraging outcome. Arthroscopic treatment of labral tears might be a useful technique in patients with hip pathologies, such as femoroacetabular impingement with labral tears.

Radiographic markers of femoroacetabular impingement: correlation of herniation pit and femoral bump with a positive cross-over ratio

Introduction. The goal of this study was to research the association of femoral bumps and herniation pits with the overlap-ratio of the cross-over sign. Methods. Pelvic X-rays and CT-scans of 2925 patients with good assessment of the anterior and the posterior acetabular wall and absence of neutral pelvic tilt were enrolled in the investigation. Finally pelvic X-rays were assessed for the presence of a positive cross-over sign, and CT-scans for a femoral bump or a herniation pit. Additionally, if a positive cross-over sign was discovered, the overlap-ratio was calculated. Results. A femoral bump was found in 53.3% (n = 1559), and a herniation pit in 27.2% (n = 796) of all hips. The overlap-ratio correlated positively with the presence of a femoral bump, while a negative correlation between the overlap-ratio and the presence of a herniation pit was found. The latter was significantly more often combined with a femoral bump than without. Conclusions. We detected an increased prevalence of femoral bump with increasing overlap-ratios of the cross-over sign indicating a relation to biomechanical stress. The observed decreased prevalence of herniation pits with increasing overlap-ratios could be explained by reduced mechanical stress due to nontightened iliofemoral ligament in the presence of retroversion of the acetabulum.

Femoroacetabular impingement in elite ice hockey players

PURPOSE

The purpose of this study is to evaluate the presence of clinical and radiological femoroacetabular impingement (FAI) in elite ice hockey players and compare it to a control group of non-athletes.

METHODS

Forty participants (20 non-athletes and 20 elite ice hockey athletes) underwent an evaluation of their hip joint, including assessment of range of motion and special provocative impingement tests. Two musculoskeletal radiologists assessed MRIs completed on each participant for radiological findings associated with FAI, including alpha angle, acetabular version angle, acetabular depth, and/or a lateral centre edge angle, and findings of labral and cartilage degeneration. A comparative analysis of the clinical and radiological findings was subsequently completed.

RESULTS

There was a significant difference in the radiological CAM impingement measured by mean alpha angle between both groups (non-athletes: 43.2 degrees, SD 9.7; and athletes: 54.2 degrees, SD 12 (p = 0.003)). There were no statistically significant differences between the groups upon evaluating PINCER impingement. There were no statistically significant differences in clinical examination findings between both groups.

CONCLUSION

MRI evidence suggests that CAM impingement is more common in the elite ice hockey athlete in comparison with non-athletes. However, as this is a pilot study examining findings in asymptomatic individuals, there is a need for a longitudinal prospective cohort study. In keeping with this, sufficient, long-term follow-up is required to assess at what point, if any, these subjects with radiological findings become symptomatic.

Biomechanical and functional indicators in male semiprofessional soccer players with increased hip alpha angles vs. amateur soccer players

Background

Femoroacetabular impingement (FAI) is predominant in young male athletes, but not much is known about gait differences in cases of increased hip alpha angles. In our study, the hip alpha angle of Nötzli of soccer players was quantified on the basis of magnetic resonance imaging (MRI) with axial oblique sequences. The aim of the current study was to compare the rearfoot motion and plantar pressure in male semiprofessional soccer players with increased alpha angles to age-matched amateur soccer players.

Methods

In a prospective analysis, male semiprofessional and amateur soccer players had an MRI of the right hip to measure the alpha angle of Nötzli. In a biomechanical laboratory setting, 14 of these participants in each group ran in two shoe conditions. Simultaneously in-shoe pressure distribution, tibial acceleration, and rearfoot motion measurements of the right foot were performed.

Results

In the semiprofessional soccer group, the mean value of the alpha angle of group was 55.1 ± 6.58° (range 43.2-76.6°) and 51.6 ± 4.43° (range 41.9-58.8°) in the amateur group. In both shoe conditions, we found a significant difference between the two groups concerning the ground reaction forces, tibial acceleration, rearfoot motion and plantar pressure parameters (P < 0.01, P < 0.05, P = 0.04). Maximum rearfoot motion is about 22% lower in the semiprofessional group compared to the amateur group in both shoe conditions.

Conclusions

This study confirmed that semiprofessional soccer players with increased alpha angles showed differences in gait kinematics compared to the amateur group. These findings support the need for a screening program for competitive soccer players. In cases of a conspicuous gait analysis and symptomatic hip pain, FAI must be ruled out by further diagnostic tests.

Application of the surgical dislocation approach to residual hip deformity secondary to Legg-Calvé-Perthes disease

Long-term prognosis after Legg-Calvé-Perthes disease (LCPD) depends on the severity of residual hip deformities including a nonspherical femoral head, a short and wide femoral neck, a high riding greater trochanter, and secondary changes in the acetabulum. Hip deformity after healed LCPD may lead to abnormal hip mechanics including femoroacetabular impingement and hip instability secondary to acetabular dysplasia. The surgical dislocation approach has recently been applied to LCPD hip deformity with encouraging short-term results. This approach allows complete dynamic evaluation of the hip joint, identification, and correction of the most common residual deformities. The purpose of this paper is to describe the application of the surgical hip dislocation approach to LCPD deformity and to evaluate the current available literature on the results of this approach to the healed LCPD hip.

The deviation of the mechanical leg axis correlates with an increased hip alpha angle and could be a predictor of femoroacetabular impingement

PURPOSE

This study was designed to evaluate whether the mechanical axis deviation (MAD) of the leg correlates with an increased hip alpha angle as described by Nötzli, which is associated with femoroacetabular impingement (FAI).

METHODS

In a retrospective analysis, standing full-length anteroposterior radiographs were analysed in patients who suffered from symptomatic leg alignment. The study included 85 radiographs of 80 patients with an average age of 43.11 years (range 18-60 years). Five patients underwent a bilateral long-leg X-ray examination. All radiographs were transferred as Digital Imaging and Communications in Medicine data files from the Picture Archiving and Communications System into the OrthoPlanner software version 2.3.2. The radiographs were measured by one orthopaedic surgeon and one independent radiologist.

RESULTS

The mean value of the alpha angle of Nötzli was 61.43° (49.07-74.04°). A total of 57 (67%) radiographs showed a varus deviation, 25 (29.5%) had a valgus malalignment and three (3.5%) a straight leg axis. Of 82 radiographs, 40 (48.8%) had a moderate axis deviation with a MAD <15 or > - 15 mm and a mean alpha angle of 57.81°, and 42 (51.2%) with extended axis deviation of a MAD > 15 or < - 15 mm had a mean alpha angle of 62.93°; 40 (95.2%) of these 42 showed an alpha angle > 55°. The alpha angle was significantly increased in extended axis deviation compared to moderate axis deviation (P = 0.001).

CONCLUSIONS

This study confirmed that increased alpha angles were found significantly at higher degrees of axis deviation on the full-length radiograph. In cases of a MAD >15 or < - 15 mm and symptomatic coxalgia, diagnostic tests must be pursued for FAI.

Is a positive femoroacetabular impingement test a common finding in healthy young adults?

BACKGROUND

Femoroacetabular impingement (FAI) is an incompletely understood clinical concept that implies pathomechanical changes in the hip as a cause for hip-related pain in young adults. While a positive anterior impingement test is suggestive of FAI, its association with clinical and radiographic findings remain unconfirmed in healthy young adults.

QUESTIONS/PURPOSES

We determined the prevalence of a positive test in 1170 young adults and examined its possible associations with (1) self-reported hip discomfort for the past 3 months; (2) weekly physical exercise; (3) hip ROM; and (4) radiographic findings associated with femoroacetabular impingement.

METHODS

We invited 2344 healthy 19-year-olds to a population-based hip study between 2008 and 2009; 1170 patients (50%) consented. The study included questionnaires on medical and functional status, a clinical hip examination including the impingement test and hip ROM, and two pelvic radiographs (AP and frog-leg views).

RESULTS

Based on at least one affected hip, 35 of 480 (7.3%) men and 32 of 672 (4.8%) women had positive impingement tests. Eighteen of the 1170 patients were excluded owing to suboptimal or missing radiographs. Self-reported hip discomfort in the women and increased physical exercise in the men were strongly associated with the positive impingement tests. Decreased abduction and internal rotation in the men, decreased flexion in both genders, and radiographic cam type findings in the men also were associated with positive tests.

CONCLUSION

A positive test for anterior impingement is not uncommon in healthy young adults, especially in males. We believe it always should be performed along with pelvic radiographs in young, active patients presenting with hip pain.

LEVEL OF EVIDENCE

Level II, diagnostic study. See the Guidelines for Authors for a complete description of level of evidence.