A Contemporary Look at the Evaluation and Treatment of Adult Borderline and Frank Hip Dysplasia

A retrospective study of arthroscopic treatment for patients with bordline developmental dysplasia of the hip

PURPOSE

Hip arthroscopy is effective in treating bordline developmental dysplasia of the hip (BDDH), but there are only a few clinical reports in China, and its postoperative failure rate is still a problem that cannot be ignored. The aim of this study was to analyze the clinical effect of hip arthroscopy in BDDH treatment in China and to explore the risk factors influencing the efficacy of hip arthroscopy in BDDH treatment.

METHODS

All of 22 cases of BDDH treated with arthroscopy in our hospital from November March 2017 to February 2022 were analyzed retrospectively, including ten males and 12 females, with an average age of 34.7 ± 9.5 years (19-53 years). All patients underwent arthroscopic treatment with acetabular plasty, labral repair, femoral osteoplasty, and capsular plication. Visual Analogue Scale (VAS), modified Harris Hip Scores (mHHS), Hip Outcome Score-activities of Daily Living (HOS-ADL) and International Hip Outcome Tool-12 (iHOT-12) were measured before operation and at the follow-up, and statistical analysis was performed. The Minimum clinically significant difference (MCID) and Patient Acceptable Symptom State (PASS) were also obtained.

RESULTS

22 patients were followed up, and the follow-up time was ≥ one year, with an average of 21.4 ± 8.2 months. The VAS score decreased from 5.27 ± 1.58 points before surgery to 1.96 ± 0.92 points at the follow-up, and the difference was statistically significant (t = 9.05,P < 0.001). The mHHS score increased from 64.84 ± 13.58 points before surgery to 90.4 ± 10.11 points at the follow-up, and the difference was statistically significant (t=-7.07, P < 0.001). The HOS-ADL score increased from 68.92 ± 11.76 points before surgery to 88.91 ± 9.51 points at the follow-up, and the difference was statistically significant (t=-8.15,P < 0.001). The iHOT-12 score increased from 49.32 ± 12.01 points before surgery to 79.61 ± 15.89 points at the follow-up, and the difference was statistically significant (t=-7.66,P < 0.001). The MCID (mHHS) and MCID (HOS-ADL) were 81.8% and 77.3% respectively, and the PASS (mHHS) and PASS (HOS-ADL) were 86.4% and 72.7% respectively at the follow-up.

CONCLUSION

Hip arthroscopy can achieve good short-term outcomes in the treatment of BDDH.

LEVEL OF EVIDENCE

IV Therapeutic Study.

How Does Radiographic Acetabular Morphology Change Between the Supine and Standing Positions in Asymptomatic Volunteers?

BACKGROUND

The radiographic appearance of the acetabulum differs between the supine and standing positions in patients with hip conditions. The pelvis undergoes a change in tilt when transitioning between positions, resulting in variations in version and acetabular coverage. However, the extent of these variations in well-functioning volunteers without compensatory patterns caused by pain is unknown.

QUESTIONS/PURPOSES

We performed this study to (1) quantify differences in radiographic acetabular measurements when transitioning between supine and standing among asymptomatic, well-functioning volunteers; (2) assess differences in pelvic tilt between positions; and (3) test whether individual anatomic parameters are associated with the change in tilt.

METHODS

This was a prospective, single-center study performed at an academic referral center. One hundred volunteers (students, staff, and patients with upper limb injuries) with well-functioning hips (Oxford hip score ≥ 45) were invited to participate. A total of 45% (45) of them were female, their mean age was 37 ± 14 years, and their mean BMI was 25 ± 2 kg/m 2 . Supine and standing AP pelvic radiographs were analyzed to determine numerous acetabular parameters including the lateral center-edge angle (LCEA), acetabular index (AI), anterior wall index (AWI), posterior wall index (PWI), crossover sign (COS), crossover ratio (COR), posterior wall sign (PWS), ischial spine sign (ISS), and femoroepiphyseal acetabular roof index (FEAR), as well as pelvic parameters including the sacrofemoral-pubic angle (SFP). Spinopelvic parameters were measured from lateral standing spinopelvic radiographs. Radiographic measurements were performed by one hip preservation research fellow and a fellowship-trained staff surgeon. Differences in parameters were determined, and correlations between postural differences and morphological parameters were tested. Clinically important differences were defined as a difference greater than 3° for acetabular angle measurements and 0.03 for acetabular ratio measurements, based on previous studies.

RESULTS

Lateral coverage angles did not show a clinically important difference between positions. AWI decreased when standing (0.47 ± 0.13 versus 0.41 ± 0.14; p < 0.001), whereas acetabular retroversion signs were more pronounced when supine (COS: 34% [34 of 100], PWS: 68% [68 of 100], and ISS: 34% [34 of 100] versus COS: 19% [19 of 100], PWS: 38% [38 of 100], and ISS: 14% [14 of 100]; all p values < 0.05). Pelvic tilt increased by a mean of 4° ± 4° when standing, but the range of change was from -15° to 7°. The change in AWI (ρ = 0.47; p < 0.001), PWI (ρ = -0.45; p < 0.001), and COR (ρ = 0.52; p < 0.001) between positions correlated with ΔSFP. Volunteers with spinal imbalance (pelvic incidence lumbar lordosis > 10°) demonstrated greater change in pelvic tilt (ΔSFP) (-7° ± 3° versus -4° ± 4°; p = 0.02) and a greater reduction in AWI (by 10%). These volunteers demonstrated reduced standing lumbar lordosis angles (45° ± 11° versus 61° ± 10°; p = 0.001).

CONCLUSION

Acetabular version increases from supine to standing because of an increase in pelvic tilt. The change in pelvic tilt between positions exhibited substantial variability. Individuals with reduced lumbar lordosis for a given pelvic incidence value demonstrated greater pelvic mobility. No features on supine radiographs were associated with the change in tilt.

CLINICAL RELEVANCE

Performing standing radiographs in addition to supine views can help identify aberrant physiologic patterns in patients with diagnostic dilemmas and might thus help with management. Normative data of pelvic tilt change can help clinicians identify patients who demonstrate excessive change in tilt that contributes to abnormal hip pathomechanics.

Midterm Outcomes After Simultaneous Hip Arthroscopic Surgery for Bilateral Femoroacetabular Impingement

BACKGROUND

Bilateral hip arthroscopic surgery for the treatment of femoroacetabular impingement (FAI) has demonstrated good outcomes at short-term follow-up, with significant improvements in pain, hip function, and patient-reported outcomes, coupled with a complication rate similar to that of unilateral surgery.

PURPOSE

To investigate whether, in patients with bilateral symptomatic FAI, simultaneous bilateral hip arthroscopic surgery is an efficacious option that produces effective midterm outcomes.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A prospective database of patients who underwent primary hip arthroscopic surgery between August 2012 and October 2020 was used to collect clinical data on 2 groups. Group 1 consisted of patients who underwent simultaneous bilateral hip arthroscopic surgery for the treatment of FAI. Group 2 represented a matched-pair control group of patients selected based on sex and age with signs and symptoms of unilateral FAI and in whom a single side was evaluated and treated. Differences in the International Hip Outcome Tool-12 and Non-Arthritic Hip Score scores were evaluated up to 5 years postoperatively.

RESULTS

In total, 171 patients (235 hips) were included, of whom 64 underwent simultaneous bilateral hip arthroscopic surgery (128 hips) and a control group of 107 patients (107 hips) underwent unilateral hip arthroscopic surgery. No significant differences were observed in International Hip Outcome Tool-12 scores between the 2 groups at 6 weeks, 3 months, 1 year, 2 years, and 5 years postoperatively. No significant differences were observed in Non-Arthritic Hip Score scores between the simultaneous bilateral and control groups at 6 weeks, 3 months, 6 months, 1 year, 2 years, and 5 years postoperatively. Overall, 18% of hips in the simultaneous bilateral group reported lateral femoral cutaneous nerve palsy at 2-week follow-up in comparison to 16% of hips in the control group.

CONCLUSION

Simultaneous bilateral hip arthroscopic surgery for the treatment of FAI represents a safe treatment option, producing effective midterm outcomes in appropriately selected patients.

The Principles of Hip Joint Preservation

The 3 primary factors involved with preservation of the hip joint are femoroacetabular impingement (FAI), hip dysplasia, and femoral torsion abnormalities. Each of these factors affects the health of the acetabular labrum and femoroacetabular cartilage. The appropriate surgical treatments for each of these factors include arthroscopic or open femoroplasty or acetabuloplasty for FAI, periacetabular osteotomy (PAO) for acetabular dysplasia, and de-rotational femoral osteotomy for femoral torsion abnormalities. When evaluating patients with prearthritic hip conditions, orthopaedic surgeons should be aware of the various factors involved in hip joint preservation and, if surgery is indicated, surgeons should be sure to address all factors that need surgical treatment rather than focusing on the most obvious issue or injury (e.g., a labral tear). The purpose of this infographic is to illustrate the importance of the factors involved in hip joint preservation and the appropriate treatments for pathology in any of these factors.

Primary Hip Arthroscopy in Patients With Acetabular Dysplasia: A Systematic Review of Published Clinical Outcomes at Minimum 5-Year Follow-up

BACKGROUND

Hip arthroscopy in patients with borderline hip dysplasia has satisfactory outcomes at short-term follow-up; however, the data on midterm outcomes are inconsistent, and failure rates are high in some studies, limiting understanding of the role and utility of hip arthroscopy in this patient cohort.

PURPOSE

To provide an up-to-date, evidence-based review of the clinical outcomes of primary hip arthroscopy in patients with frank or borderline hip dysplasia at ≥5-year follow-up and report the failure rate and progression to total hip arthroplasty in this cohort.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A comprehensive literature search was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies were included if they evaluated outcomes of primary hip arthroscopy in patients with lateral center-edge angle (LCEA) <25° at ≥5-year follow-up. Risk of bias assessment was performed using the methodological index for non-randomized studies scoring system. Level of evidence was determined using criteria from the Oxford Centre for Evidence-Based Medicine.

RESULTS

Nine studies were included in this review. Patients with LCEA <25° demonstrated satisfactory clinical outcomes, high patient satisfaction, and significant postoperative improvements in patient-reported outcomes (PROs) at follow-up ranging from a ≥5 to 10 years. Studies comparing patients with dysplasia to those without did not demonstrate significant differences in preoperative, postoperative, or delta PROs or in failure, reoperation, or revision rates. There was no overall significant correlation between outcomes and LCEA stratification.

CONCLUSION

Hip arthroscopy in carefully selected patients with LCEA <25° can be successful at mid- to long-term follow-up and may provide clinical outcomes and failure rates comparable with patients with normal LCEA, understanding that this is a singular, 2-dimensional radiographic measure that does not differentiate instability from impingement or combinations thereof, warranting future studies delineating these differences. These findings suggest that hip dysplasia may not be an absolute contraindication for isolated hip arthroscopy and may serve as a viable intervention with consideration of staged future periacetabular osteotomy (PAO). Importantly, this review does not suggest that hip arthroscopy alters the natural history of dysplasia; therefore, patients with dysplasia should be counseled on the potential utility of PAO by appropriate hip preservation specialists.

The role of different acetabular morphologies on patient-reported outcomes following periacetabular osteotomy in borderline hip dysplasia

INTRODUCTION

The treatment option for borderline hip dysplasia (BHD) includes hip arthroscopy and periacetabular osteotomy (PAO). To the present day the controversial discussion remains, which intervention to prefer. Literature reports supporting an educated choice are scare, based on small patient cohorts and do not address the variability of acetabular morphology. Consequently, we intended to report PAO outcomes, from patients diagnosed with BHD, dependent on acetabular morphology, in a large patient cohort and aimed to define risk factors for poor clinical results and patient satisfaction.

MATERIALS AND METHODS

A prospective monocentre study was conducted. Patients enrolled underwent PAO for symptomatic BHD (LCEA, 18°-25°). A total of 107 hips were included with 94 complete data sets were available for evaluation with a minimum follow-up of 1 year and a mean follow-up of 2.3 years. The mean age was 31 ± 8.2 years, and 81.3% were female. As the primary outcome measure, we utilized the modified Harris hip score (mHHS) with minimal clinically important change (MCID) of eight to define clinical failure. Results were compared after a comprehensive radiographic assessment distinguishing between lateral deficient vs. anterior/posterolateral deficient acetabular and stable vs. unstable hip joints.

RESULTS

Overall, clinical success was achieved in 91.5% of patients and the mHHS improved significantly (52 vs. 84.7, p < 0.001). Eight hips failed to achieve the MCID and four had radiographic signs of overcorrection. Comparing variable joint morphologies, the rate of clinical success was higher in patients with an anterior/posterolateral deficient acetabular covarage compared to lateral deficient acetabular (95.2% vs. 90.4%). tThe highest rate of clinical failure was recorded in unstable hip joints (85.7% vs. 92.5% in stable hips).

CONCLUSIONS

This study demonstrates that PAO is an effective means to treat symptomatic BHD with variable acetabular morphologies, achieving a clinical success in 91.5% of all patients. To maintain a high level of safety and patient satisfaction technical accuracy appears crucial.

The Principles of Hip Joint Preservation

The three primary factors involved in preservation of the hip joint include femoroacetabular impingement (FAI), hip dysplasia/instability, and femoral torsion abnormalities. Each of these factors affects the health of the acetabular labrum and femoroacetabular cartilage. The appropriate surgical treatments for each of these factors include arthroscopic or open femoroplasty/acetabuloplasty for FAI, periacetabular osteotomy for hip dysplasia/instability, and derotational femoral osteotomy for femoral torsion abnormalities. When evaluating patients with prearthritic hip conditions, orthopaedic surgeons should be aware of the various factors involved in hip joint preservation and, if surgery is indicated, the surgeon should be sure to address all factors that need surgical treatment rather than focusing on the commonly diagnosed issue or visible injury, for example, a labral tear. If any of these factors is ignored, the hip joint may not thrive. The purpose of this review was to explain the importance of the most common factors involved in hip joint preservation and the appropriate surgical treatments for pathology in these factors.

Editorial Commentary: Revision Hip Arthroscopy in Patients With Borderline Dysplasia Has a Role: Indications Are Narrow Versus Periacetabular Osteotomy

Hip arthroscopy (HA) is preferred for surgical management of femoroacetabular impingement syndrome, whereas periacetabular osteotomy (PAO) is the gold standard for frank developmental hip dysplasia in young adults. Borderline hip dysplasia (BHD) is a conundrum, with data supporting the use of either or both, not to mention that BHD is defined by varying lateral center-edge angle thresholds between 18° and 25° or 20° and 25° and features generalized ligamentous laxity and variations in acetabular and femoral version. That said, HA for BDH has been shown to have 10-year survivorship of 82%. In a revision situation after HA in patients with BHD, PAO seems a logical next step, but HA may be indicated under narrow indications. From a technical standpoint, capsular preservation, labral function restoration, and avoiding acetabular rim over-resection are key points when performing HA in BHD. Most important, particularly in the revision setting, is to determine the root cause of failure. Primarily, instability-driven symptoms are an indication for PAO.

Arthroscopic Shelf Acetabuloplasty in the Treatment of Acetabular Dysplasia Combined With Cam-Type Femoroacetabular Impingement

Acetabular dysplasia is a hip condition characterized by abnormal development of the acetabulum, which can be present from birth or develop during childhood and may persist into adulthood. Mild or borderline acetabular dysplasia frequently is associated with cam-type femoroacetabular impingement in adults. Over time, the association of impingement and abnormal contact can lead to hip pain, cartilage damage, labral tears, and an increased risk of developing hip osteoarthritis. Several surgical treatments have been proposed: arthroscopic capsular plication, periacetabular osteotomy, or shelf acetabuloplasty. As mini-invasive shelf acetabuloplasty procedure has already proven its effectiveness, an arthroscopic shelf acetabuloplasty represents a less-invasive, less-risky procedure and allows during the same procedure to perform intra-articular resection of the femoral cam, labrum repair and capsular plication. This Technical Note describes an original technique of arthroscopic shelf acetabuloplasty that combines an outside-in arthroscopic approach for the intra-articular procedure (labral repair, femoroplasty, capsular plication) and an endoscopic shelf acetabulopasty with a tricortical iliac crest autograft secure with a single cannulated screw.

The Use of Combined Hip Arthroscopy and Periacetabular Osteotomy for Hip Dysplasia Is Increasing and Has Low Complication Rates

Purpose

To analyze the annual use of hip arthroscopy (HA) and Bernese periacetabular osteotomy (PAO) for the treatment of hip dysplasia (HD), as well as postoperative outcomes, including ipsilateral reoperations.

Methods

International Classification of Diseases, Ninth and Tenth Revision, codes were used to query the PearlDiver Mariner database from January 2010 through January 2022 to identify patients aged 10 to 59 years who had a presenting diagnosis of HD and subsequently underwent (1) HA; (2) PAO; or (3) combined HA and PAO (HA-PAO, defined as PAO on the same day or within 28 days after HA). We analyzed annual rates for each treatment, as well as rates of postoperative emergency visits, readmissions, and 5-year ipsilateral secondary operations (determined via Kaplan-Meier analysis).

Results

There were 32,068 patients who underwent surgical treatment of HD. For HA, PAO, and HA-PAO, there were 29,700, 2,083, and 285 patients, respectively. All operations had the greatest percent-increase from 2015 to 2016. HA and HA-PAO peaked in 2021, whereas PAO peaked in 2019. For HA, PAO, and HA-PAO, most cases were performed in female patients and patients aged 30 to 49 years, 10 to 19 years, and 10 to 29 years, respectively. The 5-year incidence of ipsilateral secondary operations, which include revision HA, PAO, or conversion to total hip arthroplasty, was 9.2% (95% confidence interval 8.6%-9.8%) in the HA group and 6.5% (95% confidence interval 4.1%-8.8%) in the PAO group. Combining HA with PAO resulted in so few secondary operations that Kaplan-Meier analysis was infeasible. The PAO cohort had the greatest 30-day emergency visit and 90-day readmission rates, with infection as the most common cause for readmission.

Conclusions

HA is more frequently performed than PAO for hip dysplasia. HA-PAO is increasing at the greatest rate, demonstrating fewer complications and reoperations.

Level of Evidence

Level III, retrospective comparative trial.

A Modified Approach to Measuring Femoro-Epiphyseal Acetabular Roof Index Has Better Intraobserver and Interobserver Reliability Compared With the Original Femoro-Epiphyseal Acetabular Roof Index

PURPOSE

To propose a modified approach to measuring the femoro-epiphyseal acetabular roof (FEAR) index while still abiding by its definition and biomechanical basis, and to compare the intra- and interobserver reliabilities of the original and the modified FEAR index. To propose a classification for medial sourcil edges.

METHODS

We retrospectively reviewed a consecutive series of patients treated with periacetabular osteotomy and/or hip arthroscopy at a single institute. Patients with unilateral or bilateral symptomatic borderline hip(s) were included. Hips with remarkable osteoarthritis, deformities, history of previous surgery, or without symptoms were excluded. A modified FEAR index was defined using a best-fit circle to determine the sourcil line and 2 ancillary lines connecting femoral head and sourcil edges to determine epiphyseal line. Lateral center-edge angle, Sharp angle, Tönnis angle on all hips, as well as FEAR index with original and modified approaches, were measured. Intra- and interobserver reliability were calculated as intraclass correlation coefficients (ICCs) for the FEAR index with both approaches and other alignments. A classification was proposed to categorize medial sourcil edges. ICCs for the 2 approaches across different sourcil groups also were calculated.

RESULTS

After we reviewed 411 patients, 49 were finally included. Thirty-two patients (40 hips) were identified as having borderline dysplasia defined by a lateral center-edge angle of 18 to 25°. Intraobserver ICCs for the modified method were good to excellent for borderline hips; poor to excellent for developmental dysplasia of the hip; and moderate to excellent for normal hips. As for interobserver reliability, the modified approach outperformed original approach with moderate-to-good interobserver reliability (developmental dysplasia of the hip group, ICC = 0.650; borderline dysplasia group, ICC = 0.813; normal hip group, ICC = 0.709). The medial sourcil edge was classified to 3 groups upon its morphology. Type II (39.0%) and III (43.9%) sourcil were the dominant patterns. The sourcil classification had substantial intraobserver agreement (observer 4, kappa = 0.68; observer 1, kappa = 0.799) and moderate interobserver agreement (kappa = 0.465). The modified approach to FEAR index possessed greater interobserver reliability in all medial sourcil edge patterns.

CONCLUSIONS

The modified FEAR index has better intra- and interobserver reliability compared with the original approach in all hip groups and sourcil groups. Type II and III sourcil types account for the majority, to which the modified approach is better.

LEVEL OF EVIDENCE

Level II, development of diagnostic criteria (consecutive patients with consistently applied reference standard and blinding).

Primary and Revision Hip Arthroscopy in Borderline Hip Dysplasia Shows Comparable Outcomes at a Minimum 5-Year Follow-Up

PURPOSE

To compare patient-reported outcomes (PROs), achievement of clinically significant outcomes, and reoperation-free survivorship between primary and revision hip arthroscopy (HA) for femoroacetabular impingement syndrome (FAIS) in propensity-matched borderline hip dysplasia (BHD) patients at a minimum 5-year follow-up.

METHODS

Patients with BHD, characterized by a lateral center-edge angle 18° to 25°, who underwent HA for FAIS with capsular repair by a single surgeon between January 2012 and June 2018 with a minimum 5-year follow-up were identified. Cases of revision HA were propensity-matched 1:2 to cases of primary HA, controlling for age, sex, and body mass index. A 1:2 ratio was chosen to maximize the number of included patients. Collected PROs included Hip Outcome Score-Activities of Daily Living and Sport Subscales, International Hip Outcome Score 12, modified Harris Hip Score, and Visual Analog Scale for Pain. Achievement of minimal clinically important difference, patient acceptable symptom state, and substantial clinical benefit for any measured PRO was compared between groups along with reoperation-free survivorship using Kaplan-Meier analysis.

RESULTS

Thirty-six revision HA hips (34 patients) were propensity-matched to 72 primary HA hips (70 patients). The groups were similar in age (31.5 ± 10.3 years vs 30.5 ± 11.2, P = .669), sex (69.4% female vs 70.8%, P = .656), and body mass index (25.7 ± 4.0 vs 25.5 ± 3.7, P = .849). The revision group showed a greater prevalence of prolonged preoperative pain (50.0% vs 27.8%, P = .032) compared with the primary group. A significant improvement in all PROs was observed for both groups with comparable PROs preoperatively and at the 5-year follow-up between groups (P ≥ .086). The revision and primary groups showed comparable minimal clinically important difference (95.0% vs 95.7%, P ≥ .999), patient acceptable symptom state (80.0% vs 83.6%, P = .757), and substantial clinical benefit (62.5% vs 70.7%, P = .603) achievement for any PRO. Comparable reoperation-free survivorship was observed (P = .151).

CONCLUSIONS

Propensity-matched patients with BHD undergoing primary and revision hip arthroscopy for FAIS achieved similar minimum 5-year PROs, clinically significant outcomes, and reoperation-free survivorship.

LEVEL OF EVIDENCE

Level III, retrospective comparative case series.

The Everted Acetabular Labrum: Outcomes of Surgical Management

BACKGROUND

An everted acetabular labrum (EL) is a pathologic variant in which the labrum is flipped to the capsular side of the acetabular rim. An iatrogenic EL is a known complication of a poorly executed labral repair, and a recent study described the native acetabular EL.

PURPOSE

To analyze surgical outcomes after advancement or reconstruction of an EL in a native hip.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This was a multicenter retrospective review of prospectively collected data on primary hip arthroscopic surgeries performed between 2013 and 2023. An EL was identified arthroscopically as a labrum-femoral head gap while off traction in the native hip. All patients with EL who were analyzed in this study underwent arthroscopic labral repair and advancement or labral augmentation or reconstruction. Patients with hip dysplasia also underwent periacetabular osteotomy with or without a derotational femoral osteotomy. Patient-reported outcomes (PROs) were assessed using the 12-item International Hip Outcome Tool (iHOT-12) and the Nonarthritic Hip Score. PROs were obtained preoperatively and up to 24 months after surgery. PROs were compared with those of a case-matched control cohort in a 1:2 ratio. Only patients with PROs available at ≥1 year postoperatively were included in the outcome analysis.

RESULTS

A total of 111 patients (129 hips) with EL during the study period were identified, with PROs available in 96 hips. The mean age of patients with EL was 30.5 years, and women made up 87% of the cohort. Of the 129 hips with an EL, an isolated diagnosis of an EL was present in 11.6% of hips. Deficient acetabular coverage (lateral center-edge angle <25°) was seen in 40.6% of EL hips. No difference was seen in iHOT-12 scores between EL and control groups at 12- or 24-month follow-up (P = .18 and .94, respectively). Patients with EL reported a significant improvement of PROs at latest follow-up (P < .001 for iHOT-12 and Nonarthritic Hip Score).

CONCLUSION

Surgical management of a native EL with restoration of the labral seal on the femoral head and correction of concomitant pathologies resulted in significant clinical improvement, with postoperative outcome scores comparable to those of patients without an EL. These findings provide evidence supporting surgical intervention for a native EL.

Defining Thresholds and Predictors for Achieving the Patient Acceptable Symptom State for Patient-Reported Outcome Measures After Revision Hip Arthroscopy

BACKGROUND

The Patient Acceptable Symptom State (PASS) after primary hip arthroscopy has been determined; nonetheless, the PASS still needs to be defined for revision hip arthroscopy.

PURPOSE

To define minimum 2-year follow-up PASS thresholds for the modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), Hip Outcome Score-Sports Specific Subscale (HOS-SSS), visual analog scale (VAS) for pain, and International Hip Outcome Tool-12 (iHOT-12) after revision hip arthroscopy, and to identify predictors of achieving the PASS.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Data were prospectively collected and retrospectively reviewed for all patients who underwent revision hip arthroscopy between April 2017 and July 2020. Patients were included if they had baseline and minimum 2-year follow-up scores for the mHHS, NAHS, HOS-SSS, VAS for pain, and iHOT-12. PASS was calculated using the anchor-based method. Receiver operating characteristic curve analysis was used to determine the thresholds for the PASS. A multivariate logistic regression was used to identify predictors for achieving the PASS.

RESULTS

A total of 318 patients who underwent revision hip arthroscopy met the inclusion criteria. Of those patients, 292 (91.8%) had baseline and minimum 2-year follow-up. Of this group, 68 patients (72.1% female and 27.9% male; mean age, 32.9 years) answered the PASS anchor question. Achievement PASS rates were 58.8%, 41.2%, 52.9%, 60.3%, and 52.9% for the mHHS, NAHS, HOS-SSS, VAS, and iHOT-12, respectively. The area under the curve (AUC) values for the PASS for mHHS, NAHS, HOS-SSS, VAS, and iHOT-12 were 0.912, 0.888, 0.857, 0.903, and 0.871, respectively, indicating excellent discrimination. The PASS for the mHHS was 76 (sensitivity, 0.809; specificity, 0.905), for the NAHS was 86.3 (sensitivity, 0.660; specificity, 1), for the HOS-SSS was 64.3 (sensitivity, 0.745; specificity, 0.905), for the VAS was 3 (sensitivity, 0.830; specificity, 0.905), and for the iHOT-12 was 64.3 (sensitivity, 0.745; specificity, 0.905). Body mass index (BMI) was identified as a significant predictor of achieving PASS for the NAHS (OR, 0.967; 95% CI, 0.940-0.996; P = .027), as patients with a BMI ≤25.4 had 1.03 times higher odds ratio of achieving PASS for the NAHS.

CONCLUSION

After revision hip arthroscopy, the minimum 2-year follow-up PASS thresholds for the mHHS, NAHS, HOS-SSS, VAS for pain, and iHOT-12 were 76, 86.3, 64.3, 3, and 64.3, respectively. The odds ratio of achieving PASS for the NAHS was 1.03 times higher for patients with a BMI ≤25.4.

Variation in Functional Pelvic Tilt in Female Patients Undergoing Total Hip Arthroplasty With Acetabular Dysplasia

BACKGROUND

As the pelvis is a dynamic structure, the quantification of pelvic tilt (PT) should be done in different hip positions prior to total hip arthroplasty (THA). We sought to investigate functional PT in young female patients undergoing THA and explore the correlation of PT with the extent of acetabular dysplasia. Additionally, we aimed to define the PS-SI (pubic symphysis-sacroiliac joint) index as a PT quantifier on AP pelvis X-ray.

METHODS

Pre-THA female patients under the age of 50 years (n = 678) were investigated. Functional PT in 3 positions (supine, standing, and sitting) were measured. Hip parameters including lateral center-edge angle (LCEA), Tönnis angle, head extrusion index (HEI), and femoro-epiphyseal acetabular roof (FEAR) index were correlated to PT values. The PS-SI/SI-SH (sacroiliac joint-sacral height) ratio was also correlated to PT.

RESULTS

From the 678 patients, 80% were classified as having acetabular dysplasia. Among these patients, 50.6% were bilaterally dysplastic. The mean functional PT of the entire patient group was 7.4°, 4.1°, and -1.3° in the supine, standing and seated positions. The mean functional PT of the dysplastic group was 7.4°, 4.0°, and -1.2° in the supine, standing and seated positions. The PS-SI/SI-SH ratio was found to be correlated to PT.

CONCLUSION

Most of the pre-THA patients had acetabular dysplasia and exhibited anterior PT in the supine and standing positions, most pronounced in the standing position. PT values were comparable between the dysplastic and non-dysplastic group without change with worsening dysplasia. PS-SI/SI-SH ratio can be used to easily characterize PT.

Treatment of borderline hip dysplasia with triple pelvic osteotomy: preoperative values of acetabular index and lateral center edge angle can indicate overcorrection

INTRODUCTION

After pelvic osteotomy for the treatment of symptomatic hip dysplasia, the longevity of the hip joint can be compromised by acetabular overcorrection. This iatrogenic pincer-type deformity is considered to be one of the major risk factors for persistent pain and progressing osteoarthritis. There is evidence that acetabula in the borderline range, defined by a lateral center edge angle (LCEA) between 18° and 25°, are more delicate to be orientated physiologically. The aim of this study was to assess the quality of acetabular orientation by triple pelvic osteotomy (TPO), established by Tönnis and Kalchschmidt, especially with respect to acetabular overcorrection.

MATERIALS AND METHODS

A retrospective examination on 368 consecutive hips treated with TPOs was conducted. On the preoperative pelvic radiograph and the radiographic control 5 days after surgery, LCEA, acetabular index (AI), and anterior (AWI) and posterior wall index (PWI) were measured. According to the above-mentioned definition, the hips were divided into a borderline (n = 196) and a dysplastic (n = 172) group. Acetabular overcorrection was defined as when LCEA exceeded 35°, AI was below 0° and AWI exceeded 0.60, postoperatively. The postoperative occurrence of a relevant femoroacetabular impingement was correlated to these thresholds. Statistics comprised a priori power analysis, correlation analyses and receiver operating characteristics (ROC).

RESULTS

In the borderline group, in 64 hips (32.7%), LCEA and AI indicated lateral overcorrection. In the dysplastic group, in 14 hips (8.1%), solely AI indicated overcorrection. In none of the hips, relevant anterior overcorrection was detected since AWI never exceeded 0.60. Chi-square test demonstrated a significant correlation between the occurrence of a postoperative femoroacetabular impingement and LCEA exceeding 35°, as well as AI below 0° (p < 0.001, resp.). Bravais-Pearson's analysis showed a significant correlation between the pre- and postoperative values of all parameters in the borderline and the dysplasia group (p < 0.001). Thus, ROC analysis could be performed and provided preoperative cutoff values for LCEA (23°) and AI (12.5°), hinting at postoperative overcorrection.

CONCLUSION

The comparison of radiographic parameters after TPO showed a considerably greater percentage of laterally overcorrected acetabula in the borderline hips than in the dysplastic hips. According to the wall indices, anterior overcorrection was not observed. ROC analysis anticipated unfavorable lateral overcorrection when preoperative LCEA was above 23° and AI below 12.5°. These findings should sensitize the surgeon to the delicate acetabular correction in borderline dysplastic hips.

Birmingham Royal Orthopaedic Hospital (BROH) Femoral Offset-An Ancillary Measure of Adult Dysplasia of the Hip

Introduction  Adult dysplasia of the hip (ADH) is a disorder of abnormal development of the hip joint resulting in a shallow acetabulum and uncovering of the femoral head. Several radiological measurements such as the Tönnis angle (acetabular index), lateral center edge angle of Wiberg, and cross-sectional imaging parameters exist to calculate hip dysplasia. Aims  The aim of this article was to describe a new ancillary linear measure of ADH on cross-sectional imaging, the Birmingham Royal Orthopaedic Hospital (BROH) Femoral offset. Patients and Methods  Anteroposterior radiographs of the pelvis and computed tomography imaging of 100 consecutive patients with suspected hip dysplasia were reviewed. Demographic details and clinical indications were recorded. Tönnis angle was utilized to measure hip slope on radiographs and the BROH femoral offset was calculated for each patient. Student's t -test and one-way analysis of variance (ANOVA) were performed. Intraclass correlation coefficient analysis was evaluated to assess the reliability between observers. Results  There was a total of 100 patients (128 hips) included in the study (60 with normal Tönnis angle, 53 had dysplasia, and 15 had decreased Tönnis angle). The average BROH femoral offset in the dysplastic cohort was increased in comparison to the normal cohort with a statistically significant p -Value of 0.0001. The p -value was 0.00031 on ANOVA. The BROH femoral offset calculation revealed good intra- and interobserver reliability of 0.9 and 0.9, respectively. Conclusion  The BROH femoral offset can be an additional index for measuring ADH that is easier to calculate, and reproducible with good intra- and inter-observer reliability on cross-sectional imaging.

Acetabular deficiency in borderline hip dysplasia is underestimated by lateral center edge angle alone

INTRODUCTION

In hip preservation surgery, the term "borderline hip dysplasia" was used when the lateral center edge angle (LCEA), historically described by Wiberg, measured 18-25°. In recent years, several radiographic parameters have been described to assess the antero posterior coverage of the femoral head, for example, the anterior and posterior wall index (AWI and PWI). This allowed an increasingly comprehensive understanding of acetabular morphology and a questioning of the borderline definition.

MATERIAL AND METHODS

A retrospective review of 397 consecutive hips was performed, all treated with triple pelvic osteotomy (TPO) due to symptomatic hip dysplasia. On all preoperative pelvic radiographs with a LCEA of 18-25°, acetabular index (AI), AWI and PWI were measured. With these values, the hips were categorized into laterally, antero-laterally and postero-laterally dysplastic and stratified by gender. Intra- and interobserver correlation of the parameters was analyzed by intraclass correlation coefficient (ICC).

RESULTS

According to LCEA, 192 hips were identified as "borderline dysplastic". Based on AWI and PWI, the categorization resulted in 116 laterally dysplastic (60.4%), 33 antero-laterally (17.2%) and 43 postero-laterally dysplastic hips (22.4%). Gender stratification revealed that male acetabula seemed to be slightly more postero-laterally deficient than female (mean PWI 0.80 vs 0.89; p = 0.017). ICC confirmed highly accurate and reproducible readings of all parameters.

CONCLUSION

The rather high proportion of symptomatic hips labelled borderline dysplastic suggested, that there might be substantial acetabular deficiency not recognizable by LCEA. Comprehensive deformity analysis using LCEA, AI, AWI and PWI showed, that 40% of these hips were deficient either antero-laterally or postero-laterally. Male acetabula were more deficient postero-laterally than female.

Current Surgical Techniques in the Treatment of Adult Developmental Dysplasia of the Hip

The surgical protocols currently used for the treatment of developmental dysplasia of the hip (DDH) are varied, with sufficient differences in clinical outcomes that warrant a review of the role of practicing orthopedic surgeons. This paper aims to summarize the current novel techniques within the realm of surgical treatment for adult DDH, thus serving as a guide to surgeons looking to quickly familiarize themselves with available techniques. We performed computer systematic literature searches of the Embase and PubMed databases from 2010 to 2 April 2022. Study parameters as well as their respective patient reported outcomes (PROMs) were described in detail and compiled into diagrams. Two novel techniques were identified for the treatment of borderline or low-grade DDH. Six techniques which included modifications to the Bernese periacetabular osteotomy (PAO) were identified for the treatment of symptomatic DDH. Three techniques which include combinations of arthroscopy and osteotomy were identified for the treatment of DDH with concomitant hip pathologies such as cam deformities. Finally, six techniques, all of which are modifications to total hip arthroplasty (THA), were identified for the treatment of high-grade DDH. The techniques detailed in this review therefore equip surgeons with the necessary knowledge to improve outcomes in patients with varying degrees of DDH.

Evaluation of the anterior acetabular coverage with a false profile radiograph considering appropriate range of positioning

This study aimed to (1) set a reference value for anterior center edge angle (ACEA) for preoperative planning of periacetabular osteotomy (PAO), (2) investigate the effects of pelvic rotation and inclination from false profile (FP) radiographs on the measured ACEA, and (3) determine the "appropriate range of positioning" for FP radiograph. This single-centered, retrospective study analyzed 61 patients (61 hips) who underwent PAO from April 2018 and May 2021. ACEA was measured in each digitally reconstructed radiography (DRR) image of the FP radiograph reconstructed in different degrees of pelvic rotation. Detailed simulations were performed to determine the "appropriate range of positioning" (0.67 < ratio of the distance between the femoral heads to the diameter of the femoral head < 1.0). The vertical-center-anterior (VCA) angle was measured on the CT sagittal plane considering the patient-specific standing positions, and its correlation with the ACEA was investigated. The reference value of ACEA was determined by receiver operating characteristic (ROC) curve analysis. The ACEA measurement increased by 0.35° for every 1° pelvic rotation approaching the true lateral view. The pelvic rotation with the "appropriate range of positioning" was found at 5.0° (63.3-68.3°). The ACEA on the FP radiographs showed a good correlation with the VCA angle. The ROC curve revealed that an ACEA < 13.6° was associated with inadequate anterior coverage (VCA < 32°). Our findings suggest that during preoperative PAO planning, an ACEA < 13.6° on FP radiographs indicates insufficient anterior acetabular coverage. Images with the "appropriate positioning" can also have a measurement error of 1.7° due to the pelvic rotation.

Borderline Dysplasia After Primary Hip Arthroscopy with Capsular Plication and Labral Preservation: Ten-Year Survivorship and Patient-Reported Outcomes

BACKGROUND

The arthroscopic management of borderline hip dysplasia (BHD) is controversial, and long-term follow-up data are scarce. The purpose of this study was to report prospectively collected survivorship and patient-reported outcome measures (PROMs) at a minimum 10-year follow-up following primary hip arthroscopy with capsular plication and labral preservation in patients with BHD.

METHODS

Data were prospectively collected on all patients who underwent primary hip arthroscopy between September 2008 and September 2011. Patients with BHD (defined by a lateral center-edge angle [LCEA] between 18° and 25°) were included. Preoperative and minimum 10-year follow-up scores for the modified Harris hip score (mHHS), Nonarthritic Hip Score (NAHS), Hip Outcome Score-Sports Specific Subscale (HOS-SSS), and visual analog scale (VAS) for pain were collected. Exclusion criteria were prior ipsilateral hip surgery, Workers' Compensation status, Tönnis grade of >1, previous hip conditions, or LCEA of <18°. Survivorship was defined as no conversion to total hip arthroplasty (THA). The risk factors for THA conversion were analyzed. The achievement rate for the minimal clinically important difference (MCID) was reported. A propensity-matched comparison with a control group without BHD was performed.

RESULTS

Forty-five (80%) of 56 eligible hips were included in this study: 38 hips (84%) of female patients and 7 hips (16%) of male patients. The mean patient age was 31.0 ± 12.9 years, and the mean patient body mass index (BMI) was 24.5 ± 5.4 kg/m2. The 10-year survivorship was 82.2%, and there was significant improvement in all PROMs and VAS pain from baseline to the minimum 10-year follow-up (p < 0.001). The odds of undergoing conversion to THA were 4.4 times higher for patients with a BMI of ≥23 kg/m2 and 7.1 times higher for patients who were ≥42 years of age. The MCID was achieved at high rates for the mHHS (79%), NAHS (79%), HOS-SSS (70%), and VAS pain (76%). The minimum 10-year survivorship, PROMs, and MCID achievement rates for the BHD group were comparable with those for the control group.

CONCLUSIONS

Patients with BHD who underwent primary hip arthroscopy with capsular plication and labral preservation demonstrated an overall survivorship of 82.2% and significant improvement in all PROMs and achieved the MCID at high rates at a minimum 10-year follow-up.

LEVEL OF EVIDENCE

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

An Interpretable Machine Learning Model for Predicting 10-Year Total Hip Arthroplasty Risk

BACKGROUND

As the demand for total hip arthroplasty (THA) rises, a predictive model for THA risk may aid patients and clinicians in augmenting shared decision-making. We aimed to develop and validate a model predicting THA within 10 years in patients using demographic, clinical, and deep learning (DL)-automated radiographic measurements.

METHODS

Patients enrolled in the Osteoarthritis Initiative were included. DL algorithms measuring osteoarthritis- and dysplasia-relevant parameters on baseline pelvis radiographs were developed. Demographic, clinical, and radiographic measurement variables were then used to train generalized additive models to predict THA within 10 years from baseline. A total of 4,796 patients were included (9,592 hips; 58% female; 230 THAs (2.4%)). Model performance using 1) baseline demographic and clinical variables 2) radiographic variables, and 3) all variables were compared.

RESULTS

Using 110 demographic and clinical variables, the model had a baseline area under the receiver operating curve (AUROC) of 0.68 and area under the precision recall curve (AUPRC) of 0.08. Using 26 DL-automated hip measurements, the AUROC was 0.77 and AUPRC was 0.22. Combining all variables, the model improved to an AUROC of 0.81 and AUPRC of 0.28. Three of the top five predictive features in the combined model were radiographic variables including minimum joint space along with hip pain and analgesic use. Partial dependency plots revealed predictive discontinuities for radiographic measurements consistent with literature thresholds of osteoarthritis progression and hip dysplasia.

CONCLUSION

A machine learning model predicting 10-year THA performed more accurately with DL radiographic measurements. The model weighted predictive variables in concordance with clinical THA-pathology assessments.

Patients With Simple Posterior Hip Dislocations Have Higher Rates of Hip Dysplasia and Borderline Dysplasia

OBJECTIVES

To determine if patients suffering simple, posterior hip dislocations are more likely to display dysplastic characteristics of their acetabulum as compared with those suffering fracture dislocations.

DESIGN

Retrospective cohort study.

SETTING

Level 1 trauma center.

PATIENTS/PARTICIPANTS

Eighty-six patients suffering posterior, native hip dislocations over a 5-year period.

MAIN OUTCOME MEASUREMENT

The primary outcome was measurement of the lateral center edge angle (LCEA), acetabular index (AI), acetabular version, and femoro-epiphyseal acetabular roof (FEAR) index.

RESULTS

Eighteen patients (20.9%) sustained simple dislocations, whereas 68 patients (79.1%) suffered fracture dislocations. Patients with simple dislocations had decreased LCEA (25.7 vs. 34.3; P < 0.001), increased AI (7.4 vs. 5.8; P = 0.019), and decreased acetabular anteversion (14.02 vs. 18.45; P = 0.011). Additionally, patients with simple dislocations had higher rates of dysplasia and borderline dysplasia (61.1% vs. 7.3%; P < 0.001). Patients with fracture dislocations had higher rates of concomitant injuries (60.9% vs. 29.4%; P = 0.039) and higher injury severity scores (8.1 vs. 12.3; P = 0.022).

CONCLUSION

Patients who sustain simple hip dislocations are more likely to have undercoverage of the femoral head by the acetabulum as compared with patients suffering fracture dislocations. In addition, the simple dislocation group had a lower ISS and fewer concomitant injuries, which likely relates to a lower energy required for dislocation in the setting of lesser bony constraint. Surgeons treating these complicated injuries should consider measurements of LCE and AI when counseling patients on treatment strategies.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

High-Level Athletes With Borderline Hip Dysplasia Achieve Favorable Outcomes and Return to Sport Rates Following Primary Hip Arthroscopy: Minimum 5-Year Outcomes Comparison to a Propensity-Matched Control Group

PURPOSE

(1) To report minimum 5-year patient-reported outcomes (PROs) and return to sport (RTS) rates in high-level athletes with borderline hip dysplasia (BHD) following primary hip arthroscopy for labral pathology and femoroacetabular impingement syndrome and (2) to compare results to a propensity-matched control group of athletes with normal acetabular coverage.

METHODS

Data were reviewed for surgeries performed between February 2009 and February 2016. Patients were eligible if they underwent primary hip arthroscopy in the setting of BHD (lateral center-edge angle [LCEA] 18-25°) and competed in professional, collegiate, or high school sports. Inclusion criteria were preoperative and minimum 5-year follow-up scores for the modified Harris Hip Score (mHHS), Non-Arthritis Hip Score, Hip Outcome Score-Sport Specific Subscale (HOS-SSS), and visual analog scale for pain. Rates of achieving the minimal clinically importance difference (MCID), patient acceptable symptomatic state (PASS), and maximum outcome improvement satisfaction threshold (MOIST) were recorded in addition to RTS. BHD athletes were matched by age at the time of surgery, sex, body mass index, Tönnis grade, follow-up time, sport type, and competition level to a control group of 58 athletes with normal acetabular coverage (LCEA 25°-40°) for comparison.

RESULTS

A total of 34 BHD athletes were included with a mean follow-up of 73.6 ± 10.7 months. BHD athletes showed significant improvements in all PROs, demonstrated high RTS rates (90.0%), and achieved PASS/MCID/MOIST for mHHS (MCID: 80.0%, PASS: 93.3%, MOIST: 80.0%) and HOS-SSS (MCID: 76.7%, PASS: 73.3%) at high rates. When compared to a propensity-matched group with normal acetabular coverage, BHD athletes demonstrated similar postoperative PROs, rates of achieving psychometric thresholds, and RTS rates (P > .05). Additionally, by the latest follow-up, no athlete in either group required conversion to total hip arthroplasty.

CONCLUSIONS

High-level athletes with BHD undergoing primary hip arthroscopy for labral pathology and femoroacetabular impingement syndrome may expect favorable midterm outcomes and high RTS rates. These results were comparable to a control group of athletes with normal coverage.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Editorial Commentary: Most Patients With Borderline Hip Dysplasia Do Well After Hip Arthroscopy: Could Instability Be the Problem for Those Who Do Poorly?

Borderline hip dysplasia (BHD) is often defined based on the lateral center edge angle. While patients with frank hip dysplasia often require bony realignment with periacetabular osteotomy and/or derotational femoral osteotomy, patients with BHD represent an "in-between" group of patients. While many, perhaps even most, patients with BHD will have successful outcomes after hip arthroscopy alone, some will be unresponsive to an arthroscopic-only approach and require the same surgical treatments as those with frank dysplasia. A variety of radiographic and arthroscopic parameters can be used to assess the degree of instability in patients with BHD. It may be that patients with "borderline" hip dysplasia combined with hip instability are more likely to fail an arthroscopic-only approach but to date we still do not have a great algorithm for determining which patients with BHD should undergo bony treatment with periacetabular osteotomy. It is important for future studies to continue to seek out characteristics of BHD patients that predict failure of an arthroscopic-only approach. This will not only allow for optimal initial surgical treatment in "at-risk" patients with BHD but will also improve success rates in BHD patients selected for hip arthroscopy as initial surgical treatment.

Radiographic Parameters of Adult Hip Dysplasia

As knowledge about the origin and morphologic characteristics of hip pain in the young adult has evolved, so too has the clinician's ability to assess for various pathologies of the hip on radiographs, magnetic resonance imaging (MRI)/magnetic resonance arthrography (MRA), and computed tomography (CT). Because there is no algorithm at this time directly indicating what to do in more subtle hip morphologies, such as microinstability and borderline hip dysplasia (BHD), a skilled hip preservation specialist must use multiple imaging sources and know how to interpret them correctly. Imaging parameters used in the workup for hip dysplasia and BHD include the lateral center-edge angle, Tönnis angle, iliofemoral line, and presence of an upsloping lateral sourcil or everted labrum, among many others. The purpose of this narrative review was to detail various established criteria and parameters on anteroposterior pelvis plain radiographs, MRI/MRA, and CT that assist in defining the nature and severity of instability present in a dysplastic hip, thereby aiding in the development of patient-specific surgical treatment plans.

Correlation of Delayed Gadolinium-Enhanced MRI of Cartilage (dGEMRIC) Value With Hip Arthroscopy Intraoperative Findings and Midterm Periacetabular Osteotomy Outcomes

Background:

Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) is an advanced imaging technique that is purported to quantify cartilage damage in acute and chronic joint disease and predict periacetabular osteotomy (PAO) outcomes. There is a paucity of literature relating dGEMRIC values to arthroscopic findings before PAO and postoperative outcomes after PAO.

Purpose:

To assess the utility and validity of dGEMRIC as a preoperative and prognostic assessment tool of cartilage status and integrity as it relates to intraoperative findings and midterm postoperative outcomes after PAO.

Study Design:

Case series; Level of evidence, 4.

Methods:

We analyzed a cohort of 58 patients (70 hips) with a median age of 30.1 years (range, 15-50) with hip dysplasia who underwent hip arthroscopy, followed by a PAO with preoperative dGEMRIC. The primary outcome measures were intraoperative assessment and correlation with cartilage damage (presence of cartilage flap, Outerbridge grade of the acetabulum and femoral head). Secondary outcome measures were postoperative patient-reported outcome (PRO) scores, including the International Hip Outcome Tool and Non-arthritic Hip Score. Correlation analyses were performed to determine the relationship between dGEMRIC values and (1) PROs and (2) intraoperative assessment of cartilage damage.

Results:

There were significant negative linear relationships between dGEMRIC values and the primary outcome measures: presence of a cartilage flap (coronal, P = .004; sagittal, P < .001), Outerbridge grade of acetabular articular cartilage lesion (coronal, P = .002; sagittal, P = .003), and Outerbridge grade of femoral head articular cartilage lesion (coronal, P = .001; sagittal, P < .001). Despite significant overall improvement in all patients, there was no significant correlation between preoperative dGEMRIC values and improvement in PROs from presurgery to latest postoperative follow-up (median, 2.2 years; range, 1.0-5.0 years).

Conclusion:

Although dGEMRIC values (sagittal and coronal) were significant predictors of the intraoperative presence of cartilage flaps and overall cartilage integrity, they were not associated with midterm outcomes after PAO.

Borderline Developmental Dysplasia of the Hip: A Risk Factor Predicting the Development and Poor Prognosis after Core Decompression for Idiopathic Osteonecrosis of the Femoral Head

OBJECTIVE

It is unclear whether idiopathic osteonecrosis of the femoral head (ONFH) is associated with borderline developmental dysplasia of the hip (BDDH). This study aimed to compare the incidence of BDDH between patients with idiopathic ONFH and matched control subjects and determine the influence of BDDH on poor prognosis after core decompression (CD).

METHODS

We retrospectively examined 78 consecutive patients (111 hips) with idiopathic ONFH undergoing CD and 1:2 matched with 156 control subjects (222 hips). The anteroposterior pelvic radiographs were used to measure the acetabular anatomical parameters and divide included subjects into BDDH or non-BDDH group. The incidence of BDDH and acetabular anatomical parameters were compared between patients with idiopathic ONFH and matched controls. Clinical outcomes, such as Harris Hip Score (HHS), progression of collapse, and conversion to total hip arthroplasty (THA), were compared between patients with BDDH and without BDDH in the idiopathic ONFH group, with a mean follow-up of 72.1 ± 36.6 months.

RESULTS

Patients with idiopathic ONFH had a significantly higher incidence of BDDH than matched controls (29.7% vs 12.2%, p < 0.001). Less acetabular coverage was also found in patients with idiopathic ONFH than in matched controls as demonstrated by lower CEA (28.5° ± 4.7° vs 33.1° ± 5.7°, p < 0.001), AHI (82.4 ± 5.0 vs 86.3 ± 5.4, p < 0.001), ADR (299.6 ± 28.4 vs 318.8 ± 31.3, p < 0.001), and a higher sharp angle (40.0° ± 3.4° vs 37.4° ± 3.7°, p < 0.001). In patients with idiopathic ONFH, the BDDH group had a significantly lower mean HHS at the last follow-up (83.5 ± 17.4 vs 91.6 ± 9.7, p = 0.015) with a different score distribution (p = 0.004), and a lower 5-year survival rate with both clinical failure (66.7%, 95% CI 52.4%-84.9% vs 83.7%, 95% CI 75.2%-93.1%; p = 0.028) and conversion to THA (74.6%, 95% CI 60.7%-91.6% vs 92.1%, 95% CI 85.6%-99.0%; p = 0.008) as the endpoints than the non-BDDH group.

CONCLUSION

The incidence of BDDH was significantly higher in patients with idiopathic ONFH than matched controls, and idiopathic ONFH patients who underwent CD with BDDH had lower mean HHS as well as 5-year survival rate than those without BDDH. Therefore, BDDH should be considered a risk factor predicting the development of idiopathic ONFH as well as poor prognosis after CD.

Arthroscopic Treatment of Mild/Borderline Hip Dysplasia with Concomitant Femoroacetabular Impingement-Literature Review

Purpose of Review

This literature review aims to survey the current knowledge about the management FAI in the setting of borderline hip dysplasia.

Recent Findings

With better understanding, hip arthroscopy has recently been advocated for treating mild or borderline hip dysplasia (BDH) with concomitant femoroacetabular impingement (FAI) despite early studies that condemned its use. Recent outcome data have demonstrated that hip arthroscopy is a viable option in BDH, with and without FAI, and has been gaining wider acceptance. Hip arthroscopy can address the concomitant soft tissue and bony intra-articular pathologies and obviate the necessity for other surgeries. Moreover, hip arthroscopy may be used as an adjuvant treatment to other procedures such as a periacetabular osteotomy (PAO).

Summary

Hip arthroscopy for BDH is an evolving procedure with promising short- and mid-term outcomes. The combination of BDH and FAI is becoming recognized as a problem in its own right, requiring dedicated treatment.

A New Parameter of Hip Instability in Developmental Dysplasia of the Hip (DDH): Teardrop Distance

Background

Hip instability is one of the etiologies of accelerated onset of osteoarthritis in developmental dysplasia of the hip (DDH). There are some radiological parameters for hip instability in hip dysplasia like broken shenton’s line, elevated acetabular index, reduced lateral center edge angle (LCEA), upsloping lateral sourcil. We have discovered a new index of teardrop distance (TD) for assessing instability. Herein, we hypothesized that increased TD could be used as evidence of hip instability in DDH patients, which we verified using TD as an auxiliary diagnostic parameter for DDH, from supine to standing position.

Methods

Female DDH patients undergoing Bernese periacetabular osteotomy (PAO) were enrolled in the DDH group, and normal female volunteers were in the control group. Anteroposterior radiographs of the pelvis in the supine and standing positions were taken, and LCEA, Tönnis angle (TA), sharp angle (SA), and TD were tested using Stata software to analyze the changes between supine and standing anteroposterior pelvic radiographs.

Results

There were 26 female volunteers with 52 hips in the control group: supine TD 6.80 ± 0.98 mm, standing TD 6.65 ± 1.3 mm (P > 0.05). A total of 78 patients with 135 hips were included in the DDH group: supine TD 10.51 ± 3.50 mm, standing TD 10.93 ± 4.23 mm (P < 0.05). In either supine or standing position, TD in the DDH group was significantly wider than that in the control group (P < 0.05). In the DDH group, TD was correlated with TA and LCEA (rp 0.494–0.588, P < 0.05); TD was not correlated with SA, weight, or BMI (P > 0.05). There was a weak correlation between TD difference and standing LCEA (rp −0.276, P < 0.05).

Conclusion

TD > 10 mm was a common imaging feature of DDH. It increased from supine to standing position, thus indicating hip instability in DDH patients. The hip parameters of both positions should be compared, fully considering the factors of hip stability.

Increased Combined Anteversion Is an Independent Predictor of Ischiofemoral Impingement in the Setting of Borderline Dysplasia With Coxa Profunda

PURPOSE

To investigate the differences in radiologic parameters between borderline dysplasia hips (BDDH) +/- coxa profunda and normal hips and to evaluate the correlations between these parameters and the prevalence of ischiofemoral impingement (IFI) in borderline dysplasia.

METHODS

The imaging of patients with BDDH (18° ≤ lateral center edge angle <25°) treated in our hospital from January 2018 to December 2019 was retrospective reviewed. These patients were divided into BDDH with coxa profunda (acetabular fossa touches the ilioischial line, pBDDH) and without coxa profunda (nBDDH) groups. The groups were compared with a control group with normal acetabular coverage. Neck-shaft angle, femoral offset, acetabular versions, acetabular coverage, ischial angle, femoral neck version, and combined anteversion were reviewed and analyzed using computed tomography imaging using one-way analysis of variance.

RESULTS

There were 43 patients (36 female/7 male, 26.13 ± 4.96 years) in the pBDDH group, 22 patients (17 female/5 male, 28.60 ± 5.89 years) in the nBDDH group, and 23 patients (14 female/9 male, 27.67 ± 5.98 years) in the control group. The pBDDH group had increased femoral version, ischial angle, acetabular versions, and decreased ischiofemoral space (IFS)/quadratus femoris space (QFS) than the other 2 groups. The IFS/QFS correlated with neck-shaft angle, femoral offset, femoral neck version, acetabular versions, ischial angle, femoral neck-lesser trochanter angle, posterior acetabular coverage, and combined anteversion in patients with BDDH. Combined anteversion at the 3-o'clock level was an independent predictor of a decreased IFS (beta = -0.348, P = .007) and QFS (beta = -0.255, P = .01, R² = .550). Binary logistic regression demonstrated that patients with BDDH with large combined anteversion at the 3-o'clock level had a greater prevalence of IFI (odds ratio 1.148; P = .001, R² = .505).

CONCLUSIONS

In patients with borderline dysplasia, the QFS/IFS significantly correlated with combined anteversion at the 3-o'clock level on clock face of acetabulum. BDDH with coxa profunda might have a greater prevalence of IFI because of large combined anteversion.

LEVEL OF EVIDENCE

III, retrospective comparative observation study.

Functional outcomes are preserved in adult acetabular dysplasia with radiographic evidence of lumbosacral spine anomalies: an investigation in hip-spine syndrome

Purpose

Acetabular dysplasia (AD) is a debilitating condition which results in impaired hip function, leading to hip-spine syndrome with anomalies identifiable on plain radiographs. However, no study to date has investigated the association between radiographic spine anomalies and functional outcomes in AD. We hypothesize that AD patients with radiographic evidence of lumbar spine anomalies are associated with decreased function in comparison to those without such radiographic findings.

Patients and methods

One hundred thirty-five hips underwent a full four-view hip radiograph series, and two observers analyzed hip and spine variables using standard radiographs and obtained Castellvi grade, assessment of spondylolisthesis, and L4-S1 interpedicular distance. A comprehensive hip questionnaire was administered which included Harris Hip Score (HHS) and Hip Disability and Osteoarthritis Outcome Score (HOOS) to assess patient function. Correlations between HHS and HOOS and radiographic spinal measurements were calculated, and p-values were corrected for multiple comparison using the Holm’s method.

Results

Out of 135 patients, 119 were female (88.1%) and 16 were male (11.9%). Average age of presentation was 34.2 years, and average BMI was 26. There was no statistically significant correlation between Castellvi grade, presence of spondylolisthesis, or L4-S1 interpedicular distance and the patient-reported outcome measures HHS or HOOS. Conversely, a significant correlation was observed between Femoro-Epiphyseal Acetabular Roof (FEAR) index and HOOS of the contralateral hip (correlation coefficient = 0.38, adjusted p = 0.03) and Tönnis angle of AD severity and HHS of the contralateral hip (correlation coefficient = − 0.33, adjusted p = 0.04).

Conclusion

Severity of spinal anomalies measured by Castellvi grade and spondylolisthesis in patients with AD was not associated with decreased patient function in the ipsilateral diseased hip. To our knowledge, this is the first study to date to report the relationship between radiographically identifiable lumbosacral abnormalities and hip function in AD.

Prone Apprehension Relocation Test significantly correlates with radiological instability scores of the hip

Recently, there was a debate about whether borderline dysplastic hips should be treated surgically with hip arthroscopy or periacetabular osteotomy (PAO). Current studies recommend a classification into stable and unstable hips. Therefore, radiological scores have been described in recent years. Likewise, a new clinical stability test with the Prone Apprehension Relocation Test (PART) has been described. However, there has been no correlation between the modern radiological scores and the PART. We prospectively studied a consecutive group of patients who presented to our clinic. The PART and radiological scores were assessed in these patients. We divided the patients into a PART-positive and a PART-negative group and analyzed the associated clinical and radiological findings. Out of 126 patients (126 hips) included, 36 hips (29%) were evaluated as PART positive. There were significantly more females in the PART positive group (P = 0.005). Comparing the PART groups, significant differences (P < 0.0001) were found for the lateral center edge angle (LCEA), Femoro-Epiphyseal Acetabular Roof (FEAR) index, Gothic arch angle (GAA), anterior wall index (AWI), the occurrence of the upsloping lateral sourcil (ULS) and signs of acetabular retroversion. The correlation analysis showed an association between LCEA, FEAR index, GAA, AWI, ULS and the PART. A chi-square automatic interaction detection algorithm revealed that the strongest predictor of positive PART was the GAA. In conclusion, a high correlation between the PART and known radiological instability parameters was found. Consequently, a combination of clinical instability testing and radiological instability parameters should be applied to detect unstable hips.

Cleft Sign and Bone Marrow Edema of the Pubic Symphysis Are Associated With Sports and Bony Morphology in Patients With Femoroacetabular Impingement and Labral Tears

Background:

The cleft sign (CS) and bone marrow edema (BME) are considered magnetic resonance imaging (MRI) findings signifying a pubic pathology, which is associated with groin pain; however, their relationship with bony morphology related to femoroacetabular impingement (FAI) has not been established.

Purpose:

To investigate the prevalence of CS and BME in symptomatic patients with acetabular labral tears and assess their possible association with bone morphology and sport-specific activities.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

This study enrolled 418 patients (469 hips) undergoing hip arthroscopic surgery for labral tears. Also included were patients with labral tears in the setting of either hip dysplasia or borderline hip dysplasia who were undergoing endoscopic shelf acetabuloplasty combined with hip arthroscopic labral repair, cam osteoplasty, and capsular plication. All patients were screened for superior CS (SCS), inferior CS (ICS), and BME of the ipsilateral side of the pubis using 3-T MRI. We measured the following angles: lateral center edge (LCE), Sharp, Tönnis, vertical-central-anterior, and alpha. Then, we evaluated the relationship between patient characteristics and abnormal findings on MRI scans (preoperatively vs 1 year postoperatively).

Results:

An overall 397 hips were included: 200 in men and 197 in women (mean ± SD age, 35.3 ± 16.0 years). There were hips in 214 athletes (53.9%) and hips in 183 nonathletes (46.1%). MRI findings revealed SCS, ICS, and BME in 18 (4.5%), 13 (3.3%), and 34 hips (8.6%), respectively. Abnormal MRI findings at the pubis were seen more often in athletes than nonathletes (23.8% vs 3.3%), and contact sports athletes had the most frequent abnormalities. There was no SCS in patients with an LCE angle <22°. SCS was more frequently seen in those who had an alpha angle ≥71°. More than 60% of abnormal findings at the pubis diminished after arthroscopic surgery that included FAI correction and labral repair.

Conclusion:

In patients with labral tears, CS and BME were seen more frequently in athletes versus nonathletes, especially contact athletes with FAI-related bony abnormalities. More than 60% of abnormal MRI pubis findings resolved after arthroscopic treatment of FAI.

The Effect of Femoral and Acetabular Version on Outcomes Following Hip Arthroscopy: A Systematic Review

BACKGROUND

Torsional hip deformities are common among patients undergoing hip arthroscopy. However, recent studies have suggested conflicting outcomes following arthroscopy in the setting of abnormal hip version. The purpose of this study was to systematically evaluate the literature and determine the impact of femoral and acetabular version on patient-reported outcomes following primary arthroscopic hip surgery.

METHODS

This study was conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. Studies investigating femoral and acetabular version in primary hip arthroscopy with clinical outcomes were identified, and data were extracted in duplicate.

RESULTS

Overall, 11 studies met inclusion criteria and comprised 1,297 hips (726 femora and 571 acetabulae), with a mean patient age of 29.2 years (range, 14 to 74.7 years). In patients with acetabular retroversion, there was no significant difference, when compared with the normal acetabular version group, in the modified Harris hip score (mHHS), the Hip Outcome Score-Sports Specific Subscale (HOS-SSS), and visual analog scale (VAS) pain scores postoperatively. Among patients with femoral retroversion, in 2 of 3 studies, the authors reported no difference in mHHS postoperatively compared with patients with normal femoral version. In patients with high femoral anteversion, in 2 of 3 studies, the authors reported a significant difference in postoperative mHHS favoring patients with normal femoral version. Studies examining high femoral anteversion included patients with borderline hip dysplasia and patients who underwent concurrent psoas-lengthening procedures.

CONCLUSIONS

Although the definition of the normal version of the hip varied within the literature, hip arthroscopy in patients with acetabular retroversion resulted in no difference in functional outcomes compared with patients with normal version. Postoperative functional outcomes in patients with femoral retroversion and high femoral anteversion were mixed, although the procedure was possibly less effective in high femoral anteversion combined with specific clinical scenarios. Further prospective studies based on standardized definitions and version analysis techniques would be useful in identifying the precise surgical indications for safe arthroscopic surgical procedures in patients with version abnormalities of the femur and acetabulum, particularly those with high femoral anteversion and retroversion.

LEVEL OF EVIDENCE

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

Editorial Commentary: Hip Dysplasia-Arthroscopic Femoroacetabular Impingement Versus Periacetabular Osteotomy: Do Not FEAR the Size of the Next Step

Hip dysplasia is characterized by inadequate acetabular coverage of the femoral head. There is a consensus that hip dysplasia with a lateral center edge angle (LCEA) less than18° should be treated with realignment of acetabular coverage by acetabular osteotomy, but there is controversy whether milder, borderline dysplasia with an LCEA between 18° and 25° should be treated with arthroscopy or acetabular reorientation. Identifying whether the problem is related to dysplasia or femoroacetabular impingement syndrome is essential, and a crucial factor is whether the hip is unstable. A femoroepiphyseal acetabular roof (FEAR) index with a cutoff value of 2 predicts hip stability with 90% probability, even with a normative LCEA. In addition, according to the anterior-wall index (AWI), the anterior acetabular border should cross onto the middle third of the medial femoral head radius on a line that runs parallel to the femoral neck axis through the center of the femoral head. A reduced AWI suggests a deficient anterior rim. Next, lateral labrum length correlates with the FEAR index and anterior labrum length with AWI, i.e., anterior dysplasia. Consequently, the lateral labrum increases in size with progressive instability, and the anterior labrum increases in size with decreased anterior coverage. Threshold values for labrum size should be defined to guide clinical decision making. Ultimately, we require an algorithm to guide arthroscopy versus bony correction.

The Everted Acetabular Labrum: Patho-anatomy, Magnetic Resonance Imaging and Arthroscopic Findings of a Native Variant

PURPOSE

The purpose of this study was to introduce a native labral variant, the everted acetabular labrum, and to describe the patho-anatomy, magnetic resonance imaging and magnetic resonance arthrogram (MRI/MRA) characteristics and the arthroscopic findings in this condition.

METHODS

All primary hip arthroscopy procedures performed by the senior author between June 2013 and January 2020 were reviewed retrospectively. An everted acetabular labrum was identified as a segment of labrum that lacked apposition to the femoral head with the hip off traction. All everted labra were treated with labral advancement and repair with or without augmentation or reconstruction. The labrum-to-femoral head distance was measured in 3T MRI/MRA at the 1-2 o'clock position. A random selection of 38 hips without an everted labrum served as controls to compare radiographic parameters.

RESULTS

A total of 68 hips were identified as having an everted labrum during the study period (mean age, 29.1 years), and 55 hips had advanced imaging available for review. MRI/MRA scans revealed the everted labrum to have a triangular shape in 17 hips (31%) and a blunted/round shape in 38 hips (69%), which differed significantly from controls (triangular 25/38 [66%], blunted 13/38 [34%], P < 0.001). The average labrum-to-femoral head distance was 1.4 mm for everted labra versus 0.0 mm for controls (P < 0.0001) and the mean labral lengths and widths were significantly shorter than those of controls (both P < 0.01). Of the hips, 8 underwent labral reconstruction or augmentation, and 61 underwent labral advancement/repair.

CONCLUSION

The everted acetabular labrum is a native variant that is identifiable during hip arthroscopy by assessing the labral seal off traction. Preoperative MRI/MRA findings can be highly predictive of an everted labrum. Surgical treatment includes labral advancement and repair or reconstruction to restore contact between the labrum and the femoral head.

LEVEL OF EVIDENCE

III, retrospective comparative study.

The association the patient-reported outcomes after periacetabular osteotomy with radiographic features: a short-term retrospective study

BACKGROUND

Bernese periacetabular osteotomy (PAO) is an effective treatment for patients with developmental dysplasia of the hip (DDH). PAO has been widely used in China, but few follow-up outcomes have been reported in the international community. Moreover, the risk factors affecting patient-reported outcomes have not been discussed in recent studies. In this study, patient-reported outcomes after PAO were reported, and risk factors affecting patient-reported outcomes were analyzed.

METHODS

Patients who underwent PAO for DDH from January 2014 to January 2020 were selected as the study subjects, and 66 hips were included in the analysis after screening (59 patients, with an average follow-up time of 3.01 years). The Harris Hip Score (HHS) and International Hip Outcome Instrument-12 (iHOT-12) were used to assess hip function and patient quality of life. The changes of preoperative and latest follow-up HHSs less than 9 were defined as symptomatic hips, that is, an adverse outcome; otherwise, the score indicates preserved hips. Also, the changes of preoperative and latest follow-up iHOT-12 were defined as symptomatic hips and preserved hips. Multivariate logistic regression analysis was used to predict the risk factors influencing the patient-reported outcomes, and receiver operating characteristic (ROC) curve analysis was performed on the risk factors to determine their sensitivity, specificity and cutoff value.

RESULTS

Clinical outcome analysis demonstrates marked improvements in patient-reported outcomes. The multivariate logistic regression analysis showed that when the postoperative LCEA was > 38°, adverse outcomes were much more likely. However, a Tönnis angle of - 10° to 0° was a protective factor. In addition, hips with fair or poor joint congruency were more likely to develop negative outcomes. The ROC curve analysis showed that the optimal thresholds for the LCEA and Tönnis angles used to predict outcomes after PAO were 38.2° and - 9°, respectively. Based on the results of the ROC curve analysis, among hips with poor or fair joint congruency preoperatively treated by surgeons who obtained the improper postoperative LCEAs and Tönnis angles, bad patient-reported outcomes will most likely be obtained.

CONCLUSIONS

Our results demonstrate marked improvements in patient-reported outcomes. Among hips with preoperative excellent or good joint congruency treated by experienced surgeons who obtain the proper postoperative LCEA and Tönnis angles, good patient-reported outcomes can be expected.

[Recent research progress of hip-preserving treatment for adolescents and adults with developmental dysplasia of the hip]

Objective

To review the imaging evaluation, treatment progress, and controversy related to developmental dysplasia of the hip (DDH) in adolescents and adults.

Methods

The domestic and abroad hot issues related to adolescents and adults with DDH in recent years, including new imaging techniques for assessing cartilage, controversies over the diagnosis and treatment of borderline DDH (BDDH), and the improvement and prospect of peracetabular osteotomy (PAO) were summarized and analyzed.

Results

DDH is one of the main factors leading to hip osteoarthritis. As the understanding of the pathological changes of DDH continues to deepen, the use of delayed gadolinium-enhanced MRI of cartilage can further evaluate the progress of osteoarthritis and predict the prognosis after hip preservation. There are still controversies about the diagnosis and treatment of BDDH. At the same time, PAO technology and concepts are still being improved.

Conclusion

Cartilage injury and bony structure determine the choice of surgical methods and postoperative prognosis of hip preservation surgery. The hip preservation of adolescent and adult DDH patients will move towards the goal of individualization and accuracy.

Defining the Gothic Arch Angle (GAA) as a radiographic diagnostic tool for instability in hip dysplasia

In recent years, there has been a controversial discussion about whether borderline dysplastic hips should be treated with an arthroscopic procedure or rather with an acetabular reorientation. New research suggests that a classification into stable and unstable hips may be helpful. The aim of the study was to validate (1) the intra- and interobserver reliability of a newly defined radiographic parameter named the Gothic Arch Angle, (2) the association between the GAA and previously existing measurements used to define severity of acetabular dysplasia, and (3) the correlation between radiographic measurements of acetabular dysplasia with MRI findings previously suggestive of hip instability. We defined and validated the GAA in 10 standardized radiographs of asymptomatic hips by two observers and calculated intra- and interobserver coefficients at two individual dates. Subsequently, a consecutive series of 100 patients with dysplastic hips (LCEA < 25°, Toennis grade ≤ 1) were evaluated for signs of instability on anteroposterior (a.p.) pelvic radiographs and direct MR arthrography and were divided in two groups: stable and unstable. In these patients the LCEA, the AI, the FEAR index and the GAA were radiographically evaluated. Correlation analyses and a logistic regression analysis was performed to identify the predictive value of instability for each radiographic parameter. Cutoff probabilities analysis was performed using standard receiver operating characteristic (ROC) curves to rate the predictive efficiency value of the GAA. The GAA showed excellent inter- and intraobserver reliability. A correlation was found between GAA and FEAR index. A logistic regression analysis showed that LCEA, FEAR index and GAA are distinct predictors of instability in hip dysplasia. The GAA showed the largest area under the curve (AUC 0.96), indicating it to be the best predictor of instability with an optimal cutoff value of 90° (sensitivity, 0.95; specificity, 0.93). The GAA is a new available indicator for instability and is thus suggested to be used as a future radiographic parameter for the stability of dysplastic hips. Further studies are needed to understand how this parameter might additionally predict clinical outcome in the treatment of hip dysplasia.

Level of evidence: Level III, diagnostic study.

Interrater Reliability of the Prone Apprehension Relocation Test

Background:

The Prone Apprehension Relocation Test (PART) augments existing radiographic measures and clinical provocative maneuvers in diagnosing hip instability. One measure of the potential clinical utility of the PART depends on the reproducibility of test results by evaluating providers including physicians, licensed athletic trainers, and physical therapists.

Purpose:

To determine the interrater reliability of the PART among health care providers.

Study Design:

Cohort study (diagnosis); Level of evidence, 3.

Methods:

We retrospectively identified patients in our institution’s hip preservation registry who presented between September 2017 and June 2019 for evaluation of hip pain. Patients included in the study had the PART performed by a single physician as well as 1 of 12 physician extenders (a licensed athletic trainer or a physical therapist). The providers were blinded to the findings of the other examining professional. Interrater reliability was assessed using the Cohen κ (≥0.75 was considered excellent; between 0.75 and 0.40, moderate; and ≤0.40, poor).

Results:

A total of 96 patients (190 hips) were included in this study (61 women and 35 men, average age 32 ± 12.1 years). A total of 23 hips had a positive PART from both examiners. Interrater reliability was excellent between health care professionals for the PART when evaluating the right hip (κ = 0.80), left hip (κ = 0.82), and when combining the results for left and right (κ = 0.81). A subanalysis of patients with a positive PART from both raters demonstrated that 19 of the 23 hips had a lateral center-edge angle >25°.

Conclusion:

Our study demonstrated excellent interrater reliability of the PART, supporting its use in the physical evaluation of painful hips.

The crescent sign—a predictor of hip instability in magnetic resonance arthrography

Currently, much is debated on the optimal treatment of borderline hips, being in the continuum between stable and unstable hips. The diagnosis of stability is often difficult but is a prerequisite for further treatment. Analysis includes a variety of radiographic parameters. We observed that unstable hips often had a crescent-like gadolinium collection in the postero-inferior joint space. We therefore questioned if the ‘crescent sign’ could be an indicator for hip instability? A retrospective comparative study was conducted including 56 hips in the instability group (treated with PAO) and 70 hips with femoroacetabular impingement (FAI) as control group. Based on standard radiographic parameters and magnetic resonance imaging (MRI), the association between hip instability and the ‘crescent sign’ was analyzed. For univariate group comparisons, the non-parametric Wilcoxon two sample test was used. Association between discrete variables was examined by means of chi-square tests. To examine predictive variables, logistic regression models were carried out. Most hips with a crescent sign belong to the instability group. A crescent sign has a sensitivity of 73.3% and specificity of 93% for instability. Based on our results, the crescent sign is a factor that is more prevalent in unstable hips. However, its absence does not exclude instability of the hip. If present, the specificity speaks strongly in favor for instability of the hip.

Borderline Dysplastic Female Patients With Painful Internal Snapping Improve Clinical Outcomes At Minimum 2-Year Follow-Up Following Hip Arthroscopy With Femoroplasty, Labral Repair, Iliopsoas Fractional Lengthening, and Capsular Plication: A Propensity-Matched Controlled Comparison

PURPOSES

To report minimum 2-year follow-up patient-reported outcome scores (PROs) in borderline dysplastic female patients who underwent primary hip arthroscopy with femoroplasty, labral repair, iliopsoas fractional lengthening, and plication of the capsule (FLIP procedure) for cam-type femoroacetabular impingement syndrome (FAIS), labral tear, and painful internal snapping and to compare these PROs to a propensity-matched borderline dysplastic control group without painful internal snapping.

METHODS

Data were retrospectively reviewed for patients who underwent primary hip arthroscopy for cam-type FAIS and labral tear between September 2008 and May 2017. Females with borderline dysplasia (lateral center-edge angle of ≥18° to ≤25°) and painful internal snapping, who underwent the FLIP procedure, with minimum 2-year PROs for modified Harris Hip Score, Nonarthritic Hip Score, Hip Outcome Score-Sports-Specific Subscale, patient satisfaction, and visual analog scale (VAS) for pain were included. The group was matched 1:1 to a control group without painful internal snapping for age, sex, body-mass index (BMI), and surgical procedures. The minimal clinically important difference (MCID) was calculated. P-value was set at .05.

RESULTS

Seventy-four hips were included. The mean was 26.82 ± 10.49 years and 23.62 ± 4.56 kg/m² for age and BMI, respectively. Improvement was reported for all PROs and VAS (P < .0001). Twenty-nine patients were matched. At minimum 2-year follow-up, the FLIP procedure demonstrated comparable improvement in PROs and rate of achievement of MCID to the control group.

CONCLUSION

After primary hip arthroscopy and FLIP procedure, females with borderline dysplasia and painful internal snapping demonstrated significant improvement in PROs at minimum 2 years' follow-up. When compared to a propensity-matched control group without painful internal snapping, the improvement between groups was comparable.

LEVEL OF EVIDENCE

III; Case-Control study.

Achieving Successful Outcomes in High-Level Athletes With Borderline Hip Dysplasia Undergoing Hip Arthroscopy With Capsular Plication and Labral Preservation: A Propensity-Matched Controlled Study

BACKGROUND

Return to sports (RTS) rates and patient-reported outcomes (PROs) after hip arthroscopy in athletes with borderline dysplasia (BD) have not been established.

PURPOSE

(1) To report minimum 2-year PROs and RTS rates in high-level athletes with BD who underwent hip arthroscopy for labral pathology in the setting of microinstability and (2) to compare clinical results with those of a matched control group of athletes with normal acetabular coverage.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Data were reviewed for surgery performed between January 2012 and July 2018. Patients were considered eligible if they received a primary hip arthroscopy in the setting of BD (lateral center-edge angle, 18°-25°) and competed in professional, collegiate, or high school sports. Inclusion criteria included preoperative and minimum 2-year follow-up scores for the modified Harris Hip Score, Non-arthritic Hip Score, Hip Outcome Score-Sport Specific Subscale, and visual analog scale for pain. Athletes with BD were matched to a control group of athletes with normal acetabular coverage (lateral center-edge angle, 25°-40°).

RESULTS

A total of 65 patients with BD were included in the study with a mean ± standard deviation follow-up of 47.5 ± 20.4 months. Athletes with BD showed significant improvement in all outcome measures recorded, demonstrated high RTS rates (80.7%), and achieved the minimal clinically important difference (MCID) and Patient Acceptable Symptom State (PASS) for the Hip Outcome Score-Sport Specific Subscale at high rates (MCID, 90.8%; PASS, 75.4%). When compared with a propensity-matched control group with normal acetabular coverage, capsular plication was performed more commonly in the BD group (93.8% vs 82.7%; P = .037). PROs and RTS, PASS, and MCID rates were similar between the BD and control groups (P > .05).

CONCLUSION

High-level athletes with BD who undergo primary hip arthroscopy for labral pathology in the setting of microinstability may expect favorable PROs and RTS rates at minimum 2-year follow-up. These results were comparable with those of a control group of athletes with normal coverage.

Current Evidence about Developmental Dysplasia of the Hip in Pregnancy

In adults, developmental dysplasia of the hip (DDH) represents a spectrum of disorders. It is commonly found in women in routine orthopedic practice. Hip dysplasia is a leading precursor of joint laxity; when untreated, it can contribute to chronic modifications, such as thickening of the pulvinar and ligamentum teres (which can also elongate), hypertrophy of the transverse acetabular ligament, and osteoarthritis. DDH is presumed to be associated with alterations in pelvic morphology that may affect vaginal birth by the reduction in the transverse diameter of the pelvic inlet or outlet. Here, we provide an overview of the current knowledge of pregnancy-associated DDH. We primarily focused on how a surgical DDH treatment might influence the pelvic shape and size and the effects on the mechanism of birth. We presented the female pelvis from the standpoint of bone and ligament morphology relative to a pelvic osteotomy. Then, we described whether the pregnancy was impacted by previous surgical DDH treatments, performed from infancy to adulthood. In conclusion, hip dysplasia is not associated with high-risk complications during pregnancy or with increased difficulty in vaginal delivery.

Hip Dysplasia

Acetabular dysplasia represents a structural pathomorphology associated with hip pain, instability, and osteoarthritis. The wide spectrum of dysplasia anatomically refers to a 3-dimensional volumetric- and surface area-based insufficiency in coverage and is classified based on the magnitude and location of undercoverage. Borderline dysplasia has been variably defined and leads to management challenges. In symptomatic dysplasia, treatment addresses coverage with periacetabular osteotomy. Concomitant simultaneous or staged hip arthroscopy has significant advantages to address intra-articular pathology. In nonarthritic individuals, there is evidence PAO alters the natural history of dysplasia and decreases the risk of hip arthritis and total hip arthroplasty.

Revision Hip Arthroscopy in the Borderline Dysplastic Population: Reporting Outcomes With Minimum 2-Year Follow-up, With a Subanalysis Against a Propensity-Matched Nondysplastic Control Group

BACKGROUND

Hip arthroscopy in patients with borderline dysplasia continues to be surrounded by controversy. Even more controversial is the management of the failed hip arthroscopy in this population. There is a paucity of studies in contemporary literature regarding outcomes after arthroscopic revision surgery.

PURPOSE

(1) To report minimum 2-year patient-reported outcome (PRO) scores in patients with borderline dysplasia who underwent revision hip arthroscopy and (2) to compare these PRO scores with those of a propensity-matched control group without dysplasia who underwent revision hip arthroscopy.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Data were prospectively collected between August 2009 and November 2017. Inclusion criteria were revision arthroscopic surgery, capsular plication, and baseline and minimum 2-year follow-up for the following PROs: modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), Hip Outcome Score-Sports Specific Subscale (HOS-SSS), and visual analog scale (VAS) for pain. Patients with Tönnis grade >1 or previous hip conditions were excluded. Two groups were created: a study group with borderline dysplasia (lateral center-edge angle [LCEA], 18°-25°) and a control group without dysplasia (LCEA, 25°-40°). Groups were propensity-matched in a 1:3 ratio for sex, age, body mass index, and follow-up time.

RESULTS

A total of 22 revision borderline dysplastic hips (21 patients) had a minimum 2-year follow-up during the study period. Patients in this group reported significant improvements for all PROs from baseline and achieved the minimal clinically important difference (MCID) for the mHHS at a rate of 70%. Moreover, 21 borderline dysplastic hips (21 patients) were matched to 63 control hips (63 patients). Mean LCEA for the study and control groups was 22.6 ± 1.7 and 32.0 ± 5.0, respectively. Both groups reported similar improvement in all PROs. The rate for achieving the MCID for the mHHS and VAS was similar between groups; however, the control group had higher rates of meeting the MCID for the HOS-SSS and NAHS (P = .042 and P = .025, respectively). The rates of conversion to hip arthroplasty were 7.9% (n = 5) in the control group and 23.8% (n = 5) in the borderline dysplasia propensity-matched group (P = .052). The rate of re-revision arthroscopy was 11.1% (n = 7) in the control group and 19.0% (n = 4) on the borderline dysplasia group (P = .350).

CONCLUSION

After revision hip arthroscopy, significant improvement was obtained for all PROs in patients with borderline dysplasia at a minimum 2-year follow-up. Moreover, outcomes, patient satisfaction, the rate for achieving the MCID for the mHHS and VAS, and the rate for secondary surgery were similar to those of a propensity-matched control group without dysplasia. Nevertheless, there was a nonsignificant trend toward higher secondary procedures in the study group; therefore, arthroscopic revision surgery in the borderline patients should be approached with measured prognosis.