The incidence of subsequent hip arthroscopy after rectus-sparing periacetabular osteotomy.

Aims: Periacetabular osteotomy (PAO) is the preferred treatment for symptomatic acetabular dysplasia in adolescents and young adults. There remains a lack of consensus regarding whether intra-articular procedures such as labral repair or improvement of femoral offset should be performed at the time of PAO or addressed subsequent to PAO if symptoms warrant. The purpose was to determine the rate of subsequent hip arthroscopy (HA) in a contemporary cohort of patients, who underwent PAO in isolation without any intra-articular procedures. Methods: From June 2012 to March 2022, 349 rectus-sparing PAOs were performed and followed for a minimum of one year (mean 6.2 years (1 to 11)). The mean age was 24 years (14 to 46) and 88.8% were female (n = 310). Patients were evaluated at final follow-up for patient-reported outcome measures (PROMs). Clinical records were reviewed for complications or subsequent surgery. Radiographs were reviewed for the following acetabular parameters: lateral centre-edge angle, anterior centre-edge angle, acetabular index, and the alpha-angle (AA). Patients were cross-referenced from the two largest hospital systems in our area to determine if subsequent HA was performed. Descriptive statistics were used to analyze risk factors for HA. Results: A total of 16 hips (15 patients; 4.6%) underwent subsequent HA with labral repair and femoral osteochondroplasty, the most common interventions. For those with a minimum of two years of follow-up, 5.3% (n = 14) underwent subsequent HA. No hips underwent total hip arthroplasty and one revision PAO was performed. Overall, 17 hips (4.9%) experienced a complication and 99 (26.9%) underwent hardware removal. All PROMs improved significantly postoperatively. Radiologically, 80% of hips (n = 279) reached the goal for acetabular correction (77% for acetbular index and 93% for LCEA), with no significant differences between those who underwent subsequent HA and those who did not. Conclusion: Rectus-sparing PAO is associated with a low rate of subsequent HA for intra-articular pathology at a mean of 6.2 years' follow-up (1 to 11). Acetabular correction alone may be sufficient as the primary intervention for the majority of patients with symptomatic acetabular dysplasia.

Editorial Commentary: High Tibial Osteotomy and Distal Femoral Osteotomy Address Biologics and Biomechanics.

Osteotomies were historically a common treatment for knee osteoarthritis. This has given way to arthroplasty in many patients. However, osteotomies are still an excellent treatment for younger patients with malignment and joint pain. High tibial and distal femoral osteotomy are both mechanical and biological surgeries. Osteotomies about the knee result in both mechanical correction and modulation of the inflammatory environment in the joint resulting from correction of malalignment. This reinforces their importance in the treatment of the knee joint as an organ in which a complex interplay of factors is required for homeostasis. Osteotomy is a critical part of comprehensive treatment of young patients with knee pain, malignment, and cartilage disorders.

Combined Borderline Acetabular Dysplasia and Increased Femoral Anteversion Is Associated With Worse Outcomes in Female Patients Undergoing Hip Arthroscopy for Femoroacetabular Impingement.

PURPOSE: To determine the relationship of increased femoral anteversion and borderline acetabular dysplasia on the outcomes of hip arthroscopy for femoroacetabular impingement in a female cohort of patients. METHODS: This is a retrospective study of female patients undergoing hip arthroscopy for femoroacetabular impingement. All patients had preoperative radiographs and computed tomography scans from which lateral center edge angle (LCEA) and femoral anteversion were measured. Patient outcome was quantified by preoperative and postoperative International Hip Outcome Tool 12-item instrument (iHOT-12). All patients had follow-up at 2 to 4 years postoperatively. Published values for minimum clinically important difference, substantial clinical benefit (SCB), patient acceptable symptomatic state (PASS), and a normal or abnormal hip were used to determine outcome as well as the final score and delta of the iHOT-12. RESULTS: There were 243 female patients included in the cohort (83% follow-up) who had iHOT-12 scores at 2- to 4-year follow-up (mean 36.9 months). Female patients with combined LCEA ≤25° and femoral anteversion >20° had lower final IHOT-12 scores (P = .001) and delta iHOT-12 (P = .010) and were less likely to achieve a normal hip (P = .013), minimum clinically important difference (P = .018), SCB (P < .001), or PASS (P < .001) and more likely to have an abnormal hip (P = .002). In addition, patients with an LCEA ≤25° and normal femoral version were less likely to achieve a normal hip (P = .013), SCB (P < .001), and PASS (P < .001) compared with those with normal acetabular coverage (all P < .05). There was no difference in these outcome measures between the groups with an LCEA >25° with or without increased femoral version. CONCLUSIONS: Female patients with femoral anteversion >20° and borderline acetabular dysplasia did poorly after hip arthroscopy. However, those with increased femoral anteversion and normal acetabular coverage had outcomes similar to control hips. LEVEL OF EVIDENCE: Level IV, case series.

Association of Radiographic Markers of Hip Instability and Worse Outcomes 2 to 4 Years After Hip Arthroscopy for Femoroacetabular Impingement in Female Patients.

BACKGROUND: Reported outcomes of patients undergoing hip arthroscopy for femoroacetabular impingement (FAI) with underlying borderline acetabular dysplasia are mixed. This may in part be the result of mixed-sex reporting. PURPOSE: To determine the effect of radiographic measures of acetabular dysplasia and hip instability on outcomes of female patients undergoing hip arthroscopy for FAI. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: This was a retrospective study of female patients undergoing arthroscopic surgery for FAI. All patients had preoperative radiographs including a standing anteroposterior pelvic view on which lateral center-edge angle (LCEA), anterior wall index (AWI), posterior wall index (PWI), and femoroepiphyseal acetabular roof (FEAR) index were measured. Patient outcomes were quantified by preoperative and postoperative 12-Item International Hip Outcome Tool (iHOT-12) scores. All patients had follow-up at 2 to 4 years postoperatively. Published values for minimal clinically important difference (MCID), substantial clinical benefit (SCB), Patient Acceptable Symptom State (PASS), and a normal (iHOT-12 > 86 points) or abnormal (iHOT-12 < 56 points) hip were used to determine outcome, as well as the final iHOT-12 score and iHOT-12 preoperative to postoperative difference. RESULTS: The cohort consisted of 249 female patients (83% follow-up) with iHOT-12 scores at 2 to 4 years after surgery (mean, 34.6 months). Female patients with combined LCEA ≤25° and AWI <0.35 had lower final iHOT-12 score and iHOT-12 difference and were less likely to meet MCID, SCB, and PASS and have a normal hip and were more likely to have an abnormal hip as determined by iHOT-12 cutoffs when compared with those patients who had an LCEA >25° and an AWI ≥0.35 (all P < .05). There was no effect of PWI on outcomes. Similarly, female patients with combined LCEA ≤25° and a laterally oriented (positive) FEAR index were less likely to meet MCID, SCB, and PASS and have a normal hip and were more likely to have an abnormal hip compared with those patients who had an LCEA >25° and a negative (medial) FEAR index (all P < .05). In multivariate regression, an LCEA between 18° and 25° was an independent predictor of worse outcomes. CONCLUSION: An LCEA of 18° to 25°, in combination with an AWI of <0.35 or a laterally opening FEAR index, was predictive of worse outcomes in female patients undergoing hip arthroscopy for FAI.

Asymmetrically increased femoral version with high prevalence of moderate and severe femoral anteversion in unilateral Legg-Calvé-Perthes disease.

PURPOSE: To determine and stratify femoral version in Legg-Calvé-Perthes disease (LCPD), and to compare the femoral version between the LCPD hip and the contralateral unaffected hip. METHODS: We performed a retrospective review of 45 patients with unilateral LCPD who had available CT scan through the hips and knees between January 2000 and June 2017. There were 34 (76%) male cases with a mean age of 14 years (sd 4.69). Two independent readers measured femoral version on the affected and the unaffected contralateral femur. Femoral version was classified as follows: severely decreased version (< 10°); moderately decreased (10° to 14°); normal femoral version range (15° to 20°); moderately increased (21° to 25°); and severely increased version (> 25°). RESULTS: LCPD hips had predominantly increased femoral version (38% severely increased anteversion, 24% moderately increased anteversion), while 51% of the contralateral unaffected hips had normal femoral version (p < 0.001). LCPD hips had higher mean femoral version than the contralateral, unaffected side (mean difference = 13o; 95% confidence iterval 10o to 16o; p < 0.001). As the version of the affected hip increased, so did the discrepancy between sides. No effect of sex on the LCPD femoral version was detected (p = 0.34). CONCLUSION: This study included a selected group of patients with unilateral LCPD and available CT scans obtained for surgical planning. The femoral version was asymmetric, with a high proportion of excessive anteversion observed at later stages of disease in the affected hips. Future studies will be necessary to determine the pathogenesis of increased femoral version associated with LCPD. LEVEL OF EVIDENCE: Level IV, retrospective study.

Editorial Commentary: Complete Capsular Closure During Hip Arthroscopy Provides the Most Reliable and Durable Outcome . . . Capsule Closed . . . Case Closed!

The management of the hip capsule has been a recent area of controversy in hip arthroscopy. Over the past 5 years, there has been mounting biomechanical and clinical evidence that complete capsular closure is an important step to achieve the best and most durable outcome from hip arthroscopy. Numerous studies in the laboratory have shown that repairing the capsulotomy during simulated hip arthroscopy establishes normal hip biomechanics. Multiple studies have also reported improved clinical outcomes and less conversion to total hip arthroplasty in patients undergoing capsular repair. We have published that patients improve after revision hip arthroscopy for repair of capsular defects. I think it is safe to say that complete capsular closure after hip arthroscopy is becoming the standard of care in our field.

Standardizing the Diagnostic Evaluation of Nonarthritic Hip Pain Through the Delphi Method.

BACKGROUND: Femoroacetabular impingement and acetabular dysplasia have gained increased attention as nonarthritic sources of pain and dysfunction in young, active patients. To date, no standardized approach to the diagnostic evaluation of nonarthritic hip pain has been identified, as previous work has focused on the diagnostic evaluation and management of patients with femoroacetabular impingement undergoing hip arthroscopy. PURPOSE: To explore the standard diagnostic evaluation practice of experts in the field of hip preservation surgery and combine their expertise through the Delphi method to form a standardized approach to the diagnostic evaluation of patients with nonarthritic hip pain. STUDY DESIGN: Consensus statement. METHODS: An expert panel made up of 18 orthopaedic surgeons with extensive experience in the treatment of nonarthritic hip disorders participated in this Delphi study. The Delphi panelists were presented with 4 clinical vignettes representing a spectrum of patients with nonarthritic hip pain. Three iterative survey rounds were presented to the panelists based on these clinical vignettes, and a 3-step classic Delphi method was used to establish consensus techniques in the diagnostic evaluation of nonarthritic hip pain. RESULTS: Total (100%) participation was gained, with all 18 experts completing all 3 Delphi survey rounds. Consensus (≥75% support) was achieved for some, if not all, vignettes for each of the following diagnostic domains: historical features, physical examination, radiographic sequences, radiographic interpretation, cross-sectional imaging, and ancillary diagnostics. CONCLUSION: In this Delphi study, we identified standardized diagnostic treatment approaches as derived from expert opinion for patients with nonarthritic hip pathomorphologies.

Transition to Telehealth Physical Therapy After Hip Arthroscopy for Femoroacetabular Impingement: A Pilot Study With Retrospective Matched-Cohort Analysis.

BACKGROUND: Telehealth use has increased significantly of late. However, outside of total hip and knee arthroplasty, there is minimal evidence regarding its efficacy in orthopaedics and postoperative rehabilitation. PURPOSE: To determine the efficacy and cost-effectiveness of a transition to postoperative telehealth physical therapy in patients undergoing hip arthroscopy for femoroacetabular impingement (FAI). STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Included were 51 patients undergoing postoperative physical therapy after hip arthroscopy for FAI. The intervention group consisted of patients undergoing initial in-person visits followed by a transition to telehealth physical therapy for 3 months postoperatively (group 1; n = 17). Comparison groups included patients undergoing in-person physical therapy with the same physical therapy team as the telehealth group (group 2; n = 17) and patients undergoing in-person therapy with a different therapy team at the same facility (group 3; n = 17). All groups were matched 1-to-1 by patient age and sex. All patients completed the short version of the International Hip Outcome Tool (iHOT-12) both preoperatively and at 3 months postoperatively. At 3 months postoperatively, it was determined whether patients met the minimally clinically important difference (MCID; ≥13 points) or substantial clinical benefit (SCB; ≥28 points) or whether they reached a Patient Acceptable Symptomatic State (PASS; ≥64 points). Billed charges were recorded as a measure of cost. RESULTS: The overall mean age of the study patients ranged from 33 to 34 years. Among the 3 groups, there was no significant difference in the preoperative, postoperative, or pre- to postoperative change in iHOT-12 scores or in the percentage of patients meeting MCID, SCB, or PASS at 3 months. Group 1 had significantly lower mean costs ($1015.67) compared with group 2 ($1555.62; P = .011) or group 3 ($1896.38; P < .001). CONCLUSION: In this pilot study, telehealth physical therapy after hip arthroscopy was found to lead to similar short-term outcomes and was cost-effective compared with in-person physical therapy.

Acetabular Coverage Decreases at the End of Skeletal Growth: A 3DCT Study of Healthy Hips.

BACKGROUND: Abnormalities in size and position of the acetabulum have been linked to both developmental dysplasia of the hip and femoroacetabular impingement. Owing to its 3-dimensional (3D) complexity, plain radiography and cross-sectional studies [computed tomography (CT) and magnetic resonance imaging] have limitations in their ability to capture the complexity of the acetabular 3D anatomy. The goal of the study was to use 3D computed tomography reconstructions to identify the acetabular lunate cartilage and measure its size at varying ages of development and between sexes. METHODS: Patients aged 10 to 18 years with asymptomatic hips and a CT pelvis for appendicitis were reviewed. Patients were stratified by sex and age: preadolescent (10 to 12), young adolescent (13 to 15), and old adolescent (16 to 18) in equal proportions. Materialise 3-matic was used to generate a 3D pelvic model, and the acetabular lunate cartilage surface area was calculated. The lunate cartilage was divided into anatomic segments: superior (11:00 to 1:00), anterior (1:00 to 4:00), and posterior (8:00 to 11:00). The femoral head surface area was calculated to control for patient size. Mixed effects models were generated predicting segment size where side was treated as a repeated measure. Absolute and relative (lunate cartilage to femoral head) models were generated. RESULTS: Sixty-two patients (124 hips) were included. Females showed a significant decrease in femoral head coverage as age increased overall and in the 3 subsegments. The majority of changes occurred between the preadolescent and young adolescent groups. Males did not show an overall change, but the superior and anterior anatomic subgroups showed a significant decrease in coverage between the young and old adolescent groups. Male lunate cartilages were absolutely, but not relatively, larger than females. No clinically significant side-to-side differences were noted. CONCLUSIONS: The relative femoral head coverage by the acetabular lunate cartilage reduced with increasing age, suggesting the growth of the femoral head outpaces the acetabular lunate cartilage's growth. This was more prominent in females. This study has important implications for expected acetabular coverage changes in the latter aspects of pediatric and adolescent development. LEVEL OF EVIDENCE: Level III-diagnostic study.

How Common Is Femoral Retroversion and How Is it Affected by Different Measurement Methods in Unilateral Slipped Capital Femoral Epiphysis?

BACKGROUND: Although femoral retroversion has been linked to the onset of slipped capital femoral epiphysis (SCFE), and may result from a rotation of the femoral epiphysis around the epiphyseal tubercle leading to femoral retroversion, femoral version has rarely been described in patients with SCFE. Furthermore, the prevalence of actual femoral retroversion and the effect of different measurement methods on femoral version angles has yet to be studied in SCFE. QUESTIONS/PURPOSES: (1) Do femoral version and the prevalence of femoral retroversion differ between hips with SCFE and the asymptomatic contralateral side? (2) How do the mean femoral version angles and the prevalence of femoral retroversion change depending on the measurement method used? (3) What is the interobserver reliability and intraobserver reproducibility of these measurement methods? METHODS: For this retrospective, controlled, single-center study, we reviewed our institutional database for patients who were treated for unilateral SCFE and who had undergone a pelvic CT scan. During the period in question, the general indication for obtaining a CT scan was to define the surgical strategy based on the assessment of deformity severity in patients with newly diagnosed SCFE or with previous in situ fixation. After applying prespecified inclusion and exclusion criteria, we included 79 patients. The mean age was 15 ± 4 years, 48% (38 of 79) of the patients were male, and 56% (44 of 79) were obese (defined as a BMI > 95th percentile (mean BMI 34 ± 9 kg/m2). One radiology resident (6 years of experience) measured femoral version of the entire study group using five different methods. Femoral neck version was measured as the orientation of the femoral neck. Further measurement methods included the femoral head's center and differed regarding the level of landmarks for the proximal femoral reference axis. From proximal to distal, this included the most-proximal methods (Lee et al. and Reikerås et al.) and most-distal methods (Tomczak et al. and Murphy et al.). Most proximally (Lee et al. method), we used the most cephalic junction of the greater trochanter as the landmark and, most distally, we used the center base of the femoral neck superior to the lesser trochanter (Murphy et al.). The orientation of the distal femoral condyles served as the distal reference axis for all five measurement methods. All five methods were compared side-by-side (involved versus uninvolved hip), and comparisons among all five methods were performed using paired t-tests. The prevalence of femoral retroversion (< 0°) was compared using a chi-square test. A subset of patients was measured twice by the first observer and by a second orthopaedic resident (2 years of experience) to assess intraobserver reproducibility and interobserver reliability; for this assessment, we used intraclass correlation coefficients. RESULTS: The mean femoral neck version was lower in hips with SCFE than in the contralateral side (-2° ± 13° versus 7° ± 11°; p < 0.001). This yielded a mean side-by side difference of -8° ± 11° (95% CI -11° to -6°; p < 0.001) and a higher prevalence of femoral retroversion in hips with SCFE (58% [95% CI 47% to 69%]; p < 0.001) than on the contralateral side (29% [95% CI 19% to 39%]). These differences between hips with SCFE and the contralateral side were higher and ranged from -17° ± 11° (95% CI -20° to -15°; p < 0.001) based on the method of Tomczak et al. to -22° ± 13° (95% CI -25° to -19°; p < 0.001) according to the method of Murphy et al. The mean overall femoral version angles increased for hips with SCFE using more-distal landmarks compared with more-proximal landmarks. The prevalence of femoral retroversion was higher in hips with SCFE for the proximal methods of Lee et al. and Reikerås et al. (91% [95% CI 85% to 97%] and 84% [95% CI 76% to 92%], respectively) than for the distal measurement methods of Tomczak et al. and Murphy et al. (47% [95% CI 36% to 58%] and 60% [95% CI 49% to 71%], respectively [all p < 0.001]). We detected mean differences ranging from -19° to 4° (all p < 0.005) for 8 of 10 pairwise comparisons in hips with SCFE. Among these, the greatest differences were between the most-proximal methods and the more-distal methods, with a mean difference of -19° ± 7° (95% CI -21° to -18°; p < 0.001), comparing the methods of Lee et al. and Tomczak et al. In hips with SCFE, we found excellent agreement (intraclass correlation coefficient [ICC] > 0.80) for intraobserver reproducibility (reader 1, ICC 0.93 to 0.96) and interobserver reliability (ICC 0.95 to 0.98) for all five measurement methods. Analogously, we found excellent agreement (ICC > 0.80) for intraobserver reproducibility (reader 1, range 0.91 to 0.96) and interobserver reliability (range 0.89 to 0.98) for all five measurement methods in healthy contralateral hips. CONCLUSION: We showed that femoral neck version is asymmetrically decreased in unilateral SCFE, and that differences increase when including the femoral head's center. Thus, to assess the full extent of an SCFE deformity, femoral version measurements should consider the position of the displaced epiphysis. The prevalence of femoral retroversion was high in patients with SCFE and increased when using proximal anatomic landmarks. Since the range of femoral version angles was wide, femoral version cannot be predicted in a given hip and must be assessed individually. Based on these findings, we believe it is worthwhile to add evaluation of femoral version to the diagnostic workup of children with SCFE. Doing so may better inform surgeons as they contemplate when to use isolated offset correction or to perform an additional femoral osteotomy for SCFE correction based on the severity of the slip and the rotational deformity. To facilitate communication among physicians and for the design of future studies, we recommend consistently reporting the applied measurement technique. LEVEL OF EVIDENCE: Level III, prognostic study.

Surgical treatment of symptomatic post-slipped capital femoral epiphysis deformity: a comparative study between hip arthroscopy and surgical hip dislocation with or without intertrochanteric osteotomy.

PURPOSE: Our primary research question was to investigate the severity of deformity and articular damage as well as outcomes in patients undergoing hip arthroscopy compared with open surgery for the treatment of symptomatic slipped capital femoral epiphysis (SCFE) deformity. METHODS: Retrospective review of surgical treatment of symptomatic SCFE deformity with a minimum one-year follow-up. Patients were divided into three groups: the arthroscopic group, surgical hip dislocation(SHD) group and SHD with femoral osteotomy (SHD+ITO) group. Deformity severity was quantified. Hip outcome was assessed by the modified Merle d'Aubigné Postel (MDP) scores. RESULTS: There were more severe slips treated by SHD and SHD+ITO. There was more severe deformity in the SHD+ITO group than the arthroscopy group (p < 0.001). There were more full thickness acetabular cartilage defects in the SHD and the SHD+ITO groups (> 40%) compared with the arthroscopy group (11%; p = 0.03). The SHD+ITO and SHD group had lower MDP scores compared with the arthroscopy group both before and after surgery but no difference was detected in the amount of improvement from surgery across groups (p > 0.05). Moderate and severe SCFEs had worse preoperative scores but improvement was not different compared with mild SCFEs (p > 0.05). CONCLUSION: Patients undergoing open treatment had more severe SCFE deformity with more extensive articular damage at reconstructive surgery compared with patients undergoing arthroscopy. All groups with SCFE deformity had improved pain and hip function postoperatively. LEVEL OF EVIDENCE: III.

Editorial Commentary: The First Hip Arthroscopy Is the Best Hip Arthroscopy, Capsular Defect or Not.

Hip arthroscopy has evolved significantly over the last 5 to 10 years. With this comes the burden of patients with continued pain after their index procedure. Reasons for the need for revision surgery can be many, including incomplete resection of impingement morphology, unrecognized/unaddressed acetabular dysplasia or hip instability, failure to manage the soft tissue appropriately (i.e., labrum or capsule/ligament), or other unrecognized cause of pain, like femoral retroversion or subspine impingement. Like many other orthopaedic procedures, revision hip arthroscopy with or without a defect in the hip capsule has significantly worse outcomes at 2 years compared with primary hip arthroscopy. This emphasizes the importance of proper diagnosis, well-done surgery, and proper rehabilitation the first time to avoid the need for revision hip surgery in the young adult altogether.

What factors affect fluoroscopy use during Bernese periacetabular osteotomy for acetabular dysplasia?

Periacetabular osteotomy (PAO) is the treatment of choice for acetabular dysplasia in the skeletally mature. Little is known about factors affecting fluoroscopy use in PAO. Therefore, we strived to determine patient and surgery factors are associated with the amount of fluoroscopy time and radiation dose during PAO. We performed a retrospective review of 378 patients who underwent PAO between January 2012 and August 2017. The mean age was 21.7 years and 326 (86%) were females. A total of 85 patients underwent concomitant arthroscopy and 60 underwent open arthrotomy. We recorded fluoroscopy time in minutes and radiation dose area product (DAP) in mGy·m2. Multivariate general linear modeling identified independent predictors of fluoroscopy time and radiation dose. Mean fluoroscopy time was 1.21 minutes and mean fluoroscopy DAP was 0.71 mGy·m2. Multivariate predictors of increased fluoroscopy time were male gender (P = 0.001), surgeon (P < 0.001) and whether an arthroscopy was performed (P < 0.001). Multivariate predictors of increased fluoroscopy DAP were increased body mass index (BMI) (P = 0.001), surgeon (P < 0.001) and whether an arthroscopy was performed (P < 0.001). Patients undergoing hip arthroscopy concomitant to PAO are at higher risk of longer fluoroscopy time and higher radiation dose. Other factors affecting fluoroscopy time included male gender and surgeon, while radiation dose was further affected by surgeon and BMI. Our findings can facilitate discussion about the risk of radiation exposure during PAO.

The Natural History of Femoroacetabular Impingement.

BACKGROUND: Structural hip abnormalities have long been suspected of causing hip osteoarthritis. The concept of deformity of the proximal femur as a cause of osteoarthritis (OA) started with description of the tilt deformity and progressed to the pistol grip, then eventually cam-type femoroacetabular impingement (FAI). Acetabular over-coverage or retroversion as a cause of impingement is commonly referred to as pincer-type FAI. The primary research question we asked was: what is the natural history of hips with FAI? METHODS: We reviewed the literature to identify studies with cross-sectional and longitudinal evidence of the effect of FAI on the development of or association with hip OA. RESULTS: In cross-sectional and longitudinal natural history studies of hip OA, cam-type FAI has consistently shown an association with developing OA. In regard to pincer-type FAI, the data are less convincing with some studies suggesting an increased risk and others showing a protective effect of the acetabular over-coverage. It is clear that not all patients with cam FAI get OA but the altered anatomy does increase the relative risk of developing OA. CONCLUSIONS: Cam-type FAI is associated with the development of hip OA; however, there is no role for prophylactic surgery in the asymptomatic hip with the anatomy predisposing to FAI. Further interventional studies are needed to determine whether surgical correction of cam-type FAI in the symptomatic hip alters the natural history of the condition.

Automatic MRI-based Three-dimensional Models of Hip Cartilage Provide Improved Morphologic and Biochemical Analysis.

BACKGROUND: The time-consuming and user-dependent postprocessing of biochemical cartilage MRI has limited the use of delayed gadolinium-enhanced MRI of cartilage (dGEMRIC). An automated analysis of biochemical three-dimensional (3-D) images could deliver a more time-efficient and objective evaluation of cartilage composition, and provide comprehensive information about cartilage thickness, surface area, and volume compared with manual two-dimensional (2-D) analysis. QUESTIONS/PURPOSES: (1) How does the 3-D analysis of cartilage thickness and dGEMRIC index using both a manual and a new automated method compare with the manual 2-D analysis (gold standard)? (2) How does the manual 3-D analysis of regional patterns of dGEMRIC index, cartilage thickness, surface area and volume compare with a new automatic method? (3) What is the interobserver reliability and intraobserver reproducibility of software-assisted manual 3-D and automated 3-D analysis of dGEMRIC indices, thickness, surface, and volume for two readers on two time points? METHODS: In this IRB-approved, retrospective, diagnostic study, we identified the first 25 symptomatic hips (23 patients) who underwent a contrast-enhanced MRI at 3T including a 3-D dGEMRIC sequence for intraarticular pathology assessment due to structural hip deformities. Of the 23 patients, 10 (43%) were male, 16 (64%) hips had a cam deformity and 16 (64%) hips had either a pincer deformity or acetabular dysplasia. The development of an automated deep-learning-based approach for 3-D segmentation of hip cartilage models was based on two steps: First, one reader (FS) provided a manual 3-D segmentation of hip cartilage, which served as training data for the neural network and was used as input data for the manual 3-D analysis. Next, we developed the deep convolutional neural network to obtain an automated 3-D cartilage segmentation that we used as input data for the automated 3-D analysis. For actual analysis of the manually and automatically generated 3-D cartilage models, a dedicated software was developed. Manual 2-D analysis of dGEMRIC indices and cartilage thickness was performed at each "full-hour" position on radial images and served as the gold standard for comparison with the corresponding measurements of the manual and the automated 3-D analysis. We measured dGEMRIC index, cartilage thickness, surface area, and volume for each of the four joint quadrants and compared the manual and the automated 3-D analyses using mean differences. Agreement between the techniques was assessed using intraclass correlation coefficients (ICC). The overlap between 3-D cartilage volumes was assessed using dice coefficients and means of all distances between surface points of the models were calculated as average surface distance. The interobserver reliability and intraobserver reproducibility of the software-assisted manual 3-D and the automated 3-D analysis of dGEMRIC indices, thickness, surface and volume was assessed for two readers on two different time points using ICCs. RESULTS: Comparable mean overall difference and almost-perfect agreement in dGEMRIC indices was found between the manual 3-D analysis (8 ± 44 ms, p = 0.005; ICC = 0.980), the automated 3-D analysis (7 ± 43 ms, p = 0.015; ICC = 0.982), and the manual 2-D analysis.Agreement for measuring overall cartilage thickness was almost perfect for both 3-D methods (ICC = 0.855 and 0.881) versus the manual 2-D analysis. A mean difference of -0.2 ± 0.5 mm (p < 0.001) was observed for overall cartilage thickness between the automated 3-D analysis and the manual 2-D analysis; no such difference was observed between the manual 3-D and the manual 2-D analysis.Regional patterns were comparable for both 3-D methods. The highest dGEMRIC indices were found posterosuperiorly (manual: 602 ± 158 ms; p = 0.013, automated: 602 ± 158 ms; p = 0.012). The thickest cartilage was found anteroinferiorly (manual: 5.3 ± 0.8 mm, p < 0.001; automated: 4.3 ± 0.6 mm; p < 0.001). The smallest surface area was found anteroinferiorly (manual: 134 ± 60 mm; p < 0.001, automated: 155 ± 60 mm; p < 0.001). The largest volume was found anterosuperiorly (manual: 2343 ± 492 mm; p < 0.001, automated: 2294 ± 467 mm; p < 0.001). Mean average surface distance was 0.26 ± 0.13 mm and mean Dice coefficient was 86% ± 3%. Intraobserver reproducibility and interobserver reliability was near perfect for overall analysis of dGEMRIC indices, thickness, surface area, and volume (ICC range, 0.962-1). CONCLUSIONS: The presented deep learning approach for a fully automatic segmentation of hip cartilage enables an accurate, reliable and reproducible analysis of dGEMRIC indices, thickness, surface area, and volume. This time-efficient and objective analysis of biochemical cartilage composition and morphology yields the potential to improve patient selection in femoroacetabular impingement (FAI) surgery and to aid surgeons with planning of acetabuloplasty and periacetabular osteotomies in pincer FAI and hip dysplasia. In addition, this validation paves way to the large-scale use of this method for prospective trials which longitudinally monitor the effect of reconstructive hip surgery and the natural course of osteoarthritis. LEVEL OF EVIDENCE: Level III, diagnostic study.

Editorial Commentary: Acetabular Paralabral Cysts It's All About Location, Location, Location .

With our increased understanding about the causes of young adult hip pain and femoroacetabular impingement, magnetic resonance imaging has become an important diagnostic tool for identifying labral pathology. However, arthroscopic evaluation is paramount to understanding whether a labral tear truly exists in these patients. Orthopaedic dogma suggests that acetabular paralabral cysts form due to an associated acetabular labral tear. Nevertheless, a cause and effect relationship has not yet been proven in the literature. The location of these paralabral cysts may influence the clinical symptoms that they cause and their diagnostic utility. Further work is needed to fully understand the relevance of acetabular paralabral cysts in patients with femoroacetabular impingement.

Evolving Understanding of and Treatment Approaches to Slipped Capital Femoral Epiphysis.

PURPOSE OF REVIEW: To review slipped capital femoral epiphysis (SCFE), with a focus on new insights into its etiology and evolving methods of operative fixation. RECENT FINDINGS: The epiphyseal tubercle and its size during adolescence are paramount to understanding the mechanism of SCFE. In chronic stable SCFE, the epiphysis rotates about the tubercle protecting the lateral epiphyseal vessels from disruption. In an acute unstable SCFE, the tubercle displaces, increasing the risk of osteonecrosis, also known as avascular necrosis (AVN). Intraoperative stability suggests that stable and unstable SCFE based on ambulation may be inaccurate. For stable SCFE, in situ pinning remains the most accepted treatment for mild slips with delayed symptomatic femoroacetabular impingement (FAI) management. Treatment of moderate to severe stable slips with realignment osteotomy leads to less femoral deformity and potentially better outcomes. However, it has a higher risk of complications, including AVN and chondrolysis. Our knowledge of the etiology for SCFE is evolving. The optimal technique for operative treatment of moderate to severe SCFE is controversial and varies by center. Well-controlled studies of these patients are needed to understand the best treatment for this difficult problem. Furthermore, increasing the awareness about SCFE is paramount to allow for early recognition and treatment of deformity at its early stages and avoiding severe SCFE deformity which has been associated with worse long-term outcomes.

Mild or Borderline Hip Dysplasia: Are We Characterizing Hips With a Lateral Center-Edge Angle Between 18° and 25° Appropriately?

BACKGROUND: Controversy surrounds the classification and treatment of hips with a lateral center-edge angle (LCEA) between 18° and 25°. It remains undetermined as to whether periacetabular osteotomy (PAO) or arthroscopic surgery is best used to treat this patient population. HYPOTHESIS: Patients with hip pain and mild or borderline acetabular dysplasia defined by an LCEA between 18° and 25° have different features of acetabular and femoral morphology, as determined by other relevant radiographic measures assessing the anterior and posterior acetabular walls, anterior coverage of the femoral head by the acetabulum, and femoral head and neck junction sphericity. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A retrospective review of patients who had an LCEA between 18° and 25° undergoing hip preservation between January 2010 and December 2015 with either PAO or hip arthroscopic surgery was performed. Anteroposterior, Dunn lateral, and false profile radiographs were used to measure the LCEA, Tönnis angle, anterior center-edge angle (ACEA), anterior wall index (AWI) and posterior wall index (PWI), femoral epiphyseal acetabular roof (FEAR) index and posterior to anterior wall index, and alpha angle and femoral neck-shaft angle. An agglomerative hierarchical clustering analysis was then performed on the continuous radiographic variables to identify different subtypes of hip pathomorphology among the study cohort. There were sex-specific trends in hip morphology. Therefore, we proceeded to perform separate cluster analyses for each sex. Multivariate logistic regression was used to identify radiographic parameters for distinguishing between female patients who underwent hip arthroscopic surgery versus PAO. RESULTS: Ninety-eight patients with hip pain and an LCEA between 18° and 25° underwent surgery in the study period, 77 (78%) were female, and 81 (82%) had complete radiographs for cluster analyses. The mean age was 22.6 years. Hip arthroscopic surgery was performed in 40 (41%) patients, and PAO was performed in 58 (59%) patients. The ACEA (45%), FEAR index (34%), and AWI (30%) were the most commonly abnormal radiographic parameters among all patients. In female patients, the ACEA (55%), FEAR index (42%), and AWI (34%) were the most commonly abnormal radiographic parameters. In male patients, the PWI (48%) was the most common radiographic abnormality. For female patients, 3 clusters representing different patterns of hip morphology were identified: acetabular deficiency with cam morphology, lateral acetabular deficiency, and anterolateral acetabular deficiency. For male patients, 3 clusters were also identified: posterolateral acetabular deficiency with global cam morphology, posterolateral acetabular deficiency with focal cam morphology, and lateral acetabular deficiency without cam morphology. The ACEA (odds ratio [OR], 47.7 [95% CI, 9.6-237.6]; P < .001) and AWI (OR, 3.9 [95% CI, 1.0-15.0]; P = .049) were identified as independent factors predicting which procedure was performed in female patients. CONCLUSION: A comprehensive evaluation of radiographic parameters in patients with an LCEA between 18° and 25° identified sex-specific trends in hip morphology and showed a large proportion of dysplastic features among these patients. An isolated assessment of the LCEA is an oversimplistic approach that may jeopardize appropriate classification and may provide insufficient data to guide the treatment of hips with additional features of dysplasia and instability.