Faculty Bibliography

PURPOSE/OBJECTIVE:To compare femoroacetabular motion in a series of consecutive symptomatic patients with hip pain throughout the range of motion of the hip using a real-time radial gradient echo (GRE) sequence in addition to the routine hip protocol sequences for magnetic resonance (MR) arthrographic assessment of patients with and without clinical femoroacetabular impingement (FAI) syndrome. In particular, we sought to assess whether the additional dynamic sequence could differentiate between patients with and without a positive physical exam maneuver for FAI syndrome. METHODS:Patients with hip pain referred for conventional hip MR arthrogram including those with and without a positive physical exam maneuver for FAI syndrome were imaged using routine hip MR arthrogram protocol and an additional real-time radial 2-dimensional GRE acquisition at 3 Tesla in an axial oblique plane with continuous scanning of a 9 mm thick slice through the center of the femoral head-neck axis. Patients who were unable to move through the range of motion were excluded (n = 3). Patients with acetabular dysplasia (defined by a lateral center-edge angle [CEA] of 20°) were also excluded, as were patients had Kellgren and Lawrence scores of > 0. The real-time cine sequence was acquired with the patient actively moving through neutral, flexion, flexion-abduction external-rotation, and flexion-adduction internal rotation (FADIR) positions aiming for 40° of abduction, then 25° of adduction at 80° to 90° flexion. Due to the placement of the coil over the hip, a true FADIR was precluded. Images were evaluated independently by 2 musculoskeletal radiologists measuring the joint space in the anterior, central, and posterior positions at each point during range of motion for femoroacetabular cortical space (FACS). Anterior FACS narrowing was calculated as the ratio of joint space in FADIR:neutral position, with lower ratios indicating greater narrowing. Static metrics including alpha angle, CEA, grade of cartilage loss according the Outerbridge classification, and patient demographics were also recorded. RESULTS:Twenty-two painful hips in 22 patients (11 males and 11 females) with mean age 36 years (range, 15-67) were included. Twelve patients had a positive physical exam maneuver for FAI syndrome. The time to perform the dynamic sequence was 3 to 6 minutes. Interobserver agreement was strong, with intraclass correlation 0.91 and concordance correlation 0.90. According to results from both readers, patients with impingement on clinical exam had significantly lower anterior FACS ratios compared with those without clinical impingement (reader 1: 0.39 ± 0.10 vs 0.69 ± 0.20, P = .001; reader 2: 0.36 ± 0.07 vs 0.70 ± 0.17, P < .001). Decreased anterior FACS ratio was found to be significantly correlated to increased alpha angle by both readers (reader 1: R = -0.63, P = .002; reader 2: R = -0.67, P = .001) but not significantly correlated to CEA (reader 1: R = 0.13, P = .561; reader 2: R = 0.20, P = .378) or cartilage loss (reader 1: R = 0.03, P = .885; reader 2: R = -0.06, P = .784). Both readers found patients with an anterior FACS ratio of 1/2 to have significantly higher mean alpha angle (reader 1: 62.88 vs 52.79, P = .038; reader 2: 63.50 vs 50.58, P = .006); however, there were no significant differences in cartilage loss (reader 1: P = .133; reader 2: P = .882) or CEA (reader 1: P = .340; reader 2: P = .307). CONCLUSIONS:A dynamic radial 2-dimensional-GRE sequence can be added to standard hip MR arthrogram protocols in <6 minutes, allowing assessment of dynamic femoroacetabular motion with strong interreader agreement. Patients with impingement on clinical exam had significantly lower anterior FACS ratios between FADIR and neutral positions, compared with those without clinical impingement. LEVEL OF EVIDENCE/METHODS:Level III, comparative diagnostic investigation.

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/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/CONCLUSIONS: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.

Hip MRI and arthroscopy have important roles for the evaluation of the patient with hip pain. An understanding of what orthopedic surgeons want to know before and after hip arthroscopy as well as the limitations of arthroscopy would enable radiologists to improve their imaging interpretations and produce more clinically relevant, management guiding reports. The goal of this article is to review the basic principles of hip arthroscopy and MRI and compare their strengths and weaknesses. Normal clinically relevant hip anatomy, important pathologic conditions such as labral tears and cartilage injuries, femoroacetabular impingement specific findings like cam and pincer morphology, extra-articular conditions such as abductor and iliopsoas tendons pathology and common post-operative appearances are reviewed on MRI and arthroscopy.

Primary repair of acetabular labral tears has been the gold standard treatment with excellent short to mid-term results. Autograft and allograft labral reconstruction has been described mostly in the revision labral surgery setting with good short-term results. A recent study has compared primary labral reconstruction to labral repair head-to-head in the same patient. Primary labral reconstruction may be a suitable alternative to labral repair in patients with symptomatic labral pathology. Concerns remain, however, about sacrificing living labral tissue for dead allograft tissue for the long term.

Hip arthroscopy as we know it today developed over the last 15 to 20 years, yet its true beginning is far more dated. Initially developed as a means of removing loose bodies or as a means of lavage, hip arthroscopy was not utilized to treat femoroacetabular impingement (FAI) until much later. Its usefulness as a means of treating FAI did not arise until hip impingement was understood to be causal in the development of degenerative changes of the labrum and articular surfaces. As our understanding of FAI grew, the tools for treating it developed in tandem. Open treatment of FAI had been the first treatment of choice as this allowed for circumferential access to the femoral head, labrum, and acetabulum, which could be done without compromising femoral head perfusion. Yet, as arthroscopic techniques evolved, allowing for better access to the femoral head, labrum, and acetabulum, treatment of FAI with arthroscopy became the norm. However, several recent reports of revision hip arthroscopy for treatment of residual FAI have exposed potential shortcomings of arthroscopic treatment of FAI, specifically limitations with hip arthroscopy's ability to address large or complex cam and pincer deformities. While hip arthroscopy can certainly be useful for treatment of FAI in some patients, we have yet to identify which patients truly benefit from this minimally invasive approach and those who are better served by open surgical techniques. Honing our understanding of the pathology of FAI will help improve patient selection and therefore patient outcomes.

PURPOSE/OBJECTIVE:To use a large heterogeneous population to identify independent risk factors for revision surgery or conversion to total hip arthroplasty (THA) after hip arthroscopy. METHODS:The New York Statewide Planning and Research Cooperative System database was queried from 2011 through 2012 to identify patients undergoing hip arthroscopy. All patients aged 18 years or older who underwent hip arthroscopy according to Current Procedural Terminology coding were included. We chose to divide surgical volume into tertiles for the purposes of statistical analysis. Longitudinal analysis for a minimum of 2 years was performed to determine risk factors for revision surgery or conversion to THA. RESULTS:We identified 3,957 patients. The mean age was 35.8 years (standard deviation, 13.1 years). After a minimum follow-up period of 2 years, the overall failure rate was 9.6%: 3.7% of patients underwent revision hip arthroscopy at an average of 15.8 months, whereas 5.9% underwent conversion to THA at 14.7 months. Index surgery performed by surgeons in the third tertile of surgical volume (<40 cases per annum) was an independent risk factor for revision (odds ratio [OR], 1.71; P = .001), as well as conversion to THA (OR, 1.90; P < .001). Female patients (OR, 1.8; P < .001), older patients (OR, 3.4; P < .001), and patients with a history of obesity (OR, 5.6; P < .001) underwent conversion to THA at significantly higher rates than other patients. Young patients (OR, 4.4; P < .001) and female patients (OR, 1.6; P < .001) were more likely to undergo revision hip arthroscopy. CONCLUSIONS:Our analysis of 3,957 patients found that female sex, age under 40 years, absence of a labral repair, and index procedure performed by a low-volume surgeon were independent risk factors for revision hip arthroscopy. Age over 60 years, index procedure performed by a low-volume surgeon, female sex, obesity, and the presence of pre-existing arthritis were risk factors for THA conversion. LEVEL OF EVIDENCE/METHODS:Level III, case-control study.

Objectives: Hip arthroscopy for femoroacetabular impingement (FAI) and related hip pathology is increasing in volume. Variable presentations of hip pain often lead to confusion with lumbar spine pathology however. We sought to define the relationship between the lumbar spine and the hip joint. Our hypothesis is that patients with concurrent lumbar spine pathology will experience inferior outcomes after hip arthroscopy when compared to patients without lumbar spine pathology. Methods: Prospectively-collected data from a single-surgeon database from 2010 to 2014 was used to identify patients who had undergone hip arthroscopy and had documented concurrent lumbar spine pathology. Patients with spine pathology were matched by age, gender, and BMI in a 3:1 fashion to patients without spine pathology. Baseline pre-operative modified Harris Hip Scores (mHHS) were compared to scores at two-year follow-up. "Poor outcome" of initial hip arthroscopy was defined as any combination of: requiring a revision procedure, conversion to THA, or mHHS below 70. Results: 167 patients met inclusion criteria: 72.5% were "normal" while 27.5% had spine pathology. Baseline demographics were appropriately matched between cohorts (Table I). Preoperative and two-year mHHS scores were significantly different between cohorts (Figure 1). Both cohorts demonstrated significant within-group improvement at two-year follow-up, however normal patients had greater improvements than those with spine pathology (34.0 vs 31.76, p<0.001). Overall revision/THA conversion rate for entire cohort was 14.97%, with nearly twice as many spine co-pathology patients requiring additional surgery than those in the normal cohort (23.91% vs 11.57%, p=0.045). Patients with spine pathology were significantly more likely to have "poor outcomes" than those without spine pathology (36.96% vs 21.49%, p=0.048). Conclusion: Our results demonstrate that patients undergoing hip arthroscopy with concomitant lumbar spine pathology demonstrate significantly lower total improvement, significantly higher revision/THA conversion rates and significantly higher rates of suboptimal outcomes after hip arthroscopy than patients without spine pathology. (Table Presented) (Figure Presented)

Objectives: The use of hip arthroscopy for the management of hip pathology has increased dramatically in recent years. Despite evidence demonstrating excellent outcomes, there are some patients that may require revision arthroscopy or conversion to total hip arthroplasty (THA). Data regarding risk factors for poor outcomes after hip arthroscopy is limited. The purpose of this study is to evaluate the rates of revision hip arthroscopy and conversion to THA in order to identify risk factors for suboptimal outcomes. Methods: New York State Department of Health Statewide Planning and Research Cooperative Systems database was queried from 2011 through 2014 to identify patients undergoing hip arthroscopy. Patients were longitudinally followed for a minimum of two years to determine the incidence and nature of subsequent hip procedures. Multivariate logistic regression was performed to identify independent risk factors for revision surgery or conversion to THA. Results: We identified 3,957 patients who underwent hip arthroscopy. Mean age of the sample was 35.8 years (SD+/-13.1). After a minimum follow-up of two years, overall failure rate was 9.6%: 3.7% (n=148) had revision hip arthroscopy at an average of 15.8 months, while 5.9% (n=235) converted to THA at 14.7 months. Index surgery performed by surgeons in the lowest volume tertile was an independent risk factor for both revision (p=0.001) and conversion to THA (p<0.001). Females (p<0.001), older patients (p<0.001) and those with a history of obesity (p<0.001) converted to THA at a significantly higher rate than other patients. Young patients (p<0.001) and females (p<0.001) were more likely to undergo revision hip arthroscopy. Conclusion: Hip arthroscopy may be better performed by medium to high volume surgeons. Additionally, patients with identified risk factors for revision or THA conversion should be counseled pre-operatively on potentially adverse outcomes, thus allowing patient-physician engagement during the shared decision-making process

Objectives: Hip arthroscopy has been an increasingly used tool in the treatment of labral tears, chondral defects and ligamentum teres lesions and has demonstrated efficacy in returning patients to function and relieving their pain. Despite this, failures continue to occur. Our understanding of risk factors for failure or poor outcome continues to evolve as larger cohorts of patients are available for study. We sought to identify risk factors for poor outcome in our patient population. Methods: Prospectively collected data for all patients undergoing hip arthroscopy by a single fellowship-trained surgeon was obtained. All patients were indicated for hip arthroscopy based on standard pre-operative examination as well as routine and advanced imaging. Baseline demographic data regarding patient age, gender, BMI was collected. Patients without two year follow-up were excluded. Baseline pre-operative modified Harris Hip Scores (mHHS) were compared to mHHS at two-year follow-up. "Poor outcome" of initial hip arthroscopy was defined as any combination of: requiring a revision procedure or conversion to THA or mHHS below 70. Multivariate logistic regression was performed to identify independent risk factors for "poor outcome." Results: 258 patients met inclusion criteria. Mean age (SD) and body mass index (BMI) were 40.4 years (12.7 years) and 25.6 (4.7) respectively. 62.8% (162/258) of the sample was female. Mean preoperative baseline mHHS was 49.6 (12.5) and average mHHS at two year follow-up was 83.6 (15.6), resulting in a mean improvement of 34.1 (p<0.001). Baseline and 2 year differencess in mHHS by demographic be found in Figures 1,2,3. Overall revision/THA conversion rate was 16.7% (43/258), while another 10.5% (27/258) of patients reported outcome scores <70, resulting in 27.31% (70/258) having poor outcomes. Independent risk factors for poor outcome were female gender (OR 1.79; p=0.03), obesity (OR 2.1; p=0.04), and pre-operative mHHS lower than 40 (OR 3.34, p<0.001). Conclusion: Our findings that female gender, obesity and poorer preoperative functional status increase the risk for failure of hip arthroscopy coincide and add to an increasing volume of literature examining risk factors for poor outcome after hip arthroscopy. These factors should be taken into consideration with operative indications as well as in counseling patients

The acetabular labrum and the transverse acetabular ligament form a continuous ring of tissue on the periphery of the acetabulum that provides a seal for the hip joint and increases the surface area to spread load distribution during weight-bearing. When a labral tear is suspected, the treatment algorithm always begins with conservative management, including physical therapy and nonsteroidal anti-inflammatory drugs. When conservative management fails, patients become candidates for arthroscopic labral repair. In the last 2 decades, the rate of hip arthroscopy has increased nearly 4-fold. However, as hip arthroscopy is performed more frequently, there is a need for a proper technique to minimize morbidity, because hip arthroscopy has been known to have a steep learning curve. We present a method for arthroscopic hip labral repair using suture anchors without a capsular repair. This Technical Note highlights our technique for labral repair, along with pearls and pitfalls of hip arthroscopy.