No Difference in Patient-Reported Outcomes for Periacetabular Osteotomy and Hip Arthroscopy With Capsular Plication in the Setting of Borderline Hip Dysplasia: A Propensity-Matched Multicenter Study With Minimum 5-Year Follow-Up

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.

Concomitant Peri-Acetabular Osteotomy and Arthroscopy Versus Isolated Arthroscopy With Capsular Plication for Borderline Dysplasia: Two Good Options

PURPOSE

To compare minimum 2-year outcomes of periacetabular osteotomy (PAO) with concomitant hip arthroscopy (HA) versus isolated HA with capsular plication in patients with borderline hip dysplasia (BHD).

METHODS

Data were retrospectively reviewed for patients who underwent surgery for femoroacetabular impingement in the setting of BHD between September 2008 and December 2021. Included patients had preoperative and minimum 2-year patient-reported outcome (PRO) scores. Patients who underwent staged PAO and HA comprised the PAO group. Patients who underwent isolated HA with capsular plication comprised the HA group. Matching occurred at a 1:1 ratio based on age, sex, body mass index, and Tönnis grade.

RESULTS

A total of 74 hips were included. In the HA group, the mean postoperative modified Harris Hip Score, Nonarthritic Hip Score, Hip Outcome Score-Sports Specific Subscale, and visual analog scale score were 90.32 ± 12.39, 89.46 ± 11.57, 81.47 ± 20.54, and 1.74 ± 1.89, respectively. In the PAO group, these PRO values were 90.69 ± 13.46, 91.59 ± 10.80, 82.20 ± 21.23, and 1.49 ± 1.94, respectively. The HA group met the minimal clinically important difference for the modified Harris Hip Score (89.19%), Nonarthritic Hip Score (86.49%), and Hip Outcome Score-Sports Specific Subscale (72.97%) at similar rates to the PAO group (89.19%, 86.49%, and 78.38%, respectively). The rates of achieving the patient acceptable symptom state for these PROs were 86.49%, 72.97%, and 67.57%, respectively, in the HA group and 86.49%, 78.38%, and 70.27%, respectively, in the PAO group. The rates of achieving maximal outcome improvement for these PROs were 81.1%, 75.68%, and 70.27%, respectively, in the HA group and 75.68%, 75.68%, and 70.27%, respectively, in the PAO group. Complications occurred in 10.81% of patients in the PAO group and 5.41% of those in the HA group (P = .67).

CONCLUSIONS

PAO with concomitant HA and isolated HA with capsular plication in the setting of BHD yielded favorable and comparable outcomes. A high percentage of patients in both the HA and PAO groups reached clinically relevant thresholds, with similar rates of revision and conversion to arthroplasty at minimum 2-year follow-up.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

What Are the Minimum Clinically Important Difference, Substantial Clinical Benefit, and Patient-Acceptable Symptom State Thresholds for the Modified Harris Hip Score and International Hip Outcome Tool 12 Among Patients Who Undergo Periacetabular Osteotomy?

BACKGROUND

The utility of patient-reported outcome measures (PROMs) has been well established, but their interpretation relies on population-specific definitions of meaningful improvement. As such, the minimum clinically important difference (MCID), substantial clinical benefit (SCB), and patient-acceptable symptom state (PASS) thresholds have become prominent metrics in the orthopaedic evidence to ascribe clinical relevance to numeric PROM scores. Studies assessing outcomes of periacetabular osteotomy (PAO) relative to the MCID and PASS have previously evaluated patients against thresholds defined for hip arthroscopy for the treatment of femoroacetabular impingement or distribution-based MCID calculations. These scores may not accurately reflect the status or expectations of patients with a different symptom profile undergoing open hip preservation surgery.

QUESTIONS/PURPOSES

For patients treated with PAO, we sought to (1) define the MCID, SCB, and PASS threshold values for the mHHS (modified Harris hip score) and International Hip Outcome Tool 12 (iHOT-12) using anchor-based methods; (2) assess the validity of MCID and SCB estimates against minimal detectable change (MDC) values; and (3) determine the proportion of patients who achieved a clinically meaningful threshold.

METHODS

Between February 2011 and May 2023, a total of 690 patients underwent PAO for symptomatic acetabular dysplasia at one institution and were included in a longitudinally maintained hip preservation registry. The cohort used to define and validate MCID, SCB, and PASS threshold values consisted of those with a completed postoperative anchor questionnaire, which yielded 456 patients as potentially eligible. An additional 139 patients were excluded because of missing mHHS or iHOT-12 scores during the eligibility window (1 to 2 years postoperatively), leaving 70% (317 of 456) of patients to define and validate MCID, SCB, and PASS at a mean ± SD of 1.0 ± 0.3 years of follow-up. A minimum 1-year follow-up was chosen to reduce recall bias. The cohort for defining MCID, SCB, and PASS (94% [298 of 317] women, mean ± SD age at time of surgery 27 ± 8 years) included 21% (68 of 317) of patients with prior ipsilateral surgery. From those registry patients without complete anchor questionnaires, 37% (137 of 373) were identified with pre- and postoperative PROM scores at a mean ± SD of 1.0 ± 0.9 years of follow-up to form the sample for assessing the proportion of patients achieving a clinically meaningful threshold. The MCID, SCB, and PASS thresholds for the mHHS and iHOT-12 were calculated through an anchor-based approach, using area under the receiver operating curve to determine cut points that best identified positive responses, according to quality of life-based anchor questions. The MDC was calculated with confidence intervals (CIs) reflecting 80%, 90%, and 95% certainty to determine the smallest change in the PROM scores that can be considered above the level of measurement error. The validity of MCID estimates was assessed by confirming that they exceeded corresponding MDC values. The validity of SCB estimates were assessed by confirming that they exceeded corresponding MCID values. The proportion of patients achieving a clinically meaningful threshold was determined by calculating the percentage of patients who met the defined anchor-based scores.

RESULTS

The MCID, SCB, and PASS thresholds for the mHHS were 18, 23, and 71, respectively. The MCID, SCB, and PASS thresholds for the iHOT-12 were 26, 42, and 65, respectively. The MDC ranged from 8 to 12 for the mHHS and 10 to 16 for the iHOT-12. The MCID values for the mHHS and iHOT-12 exceeded corresponding values of the MDC at all CIs. The SCB thresholds exceeded all corresponding MDC and MCID values. Across the mHHS and iHOT-12, the proportion of patients who achieved an MCID at the first time point ranged from 60% to 73%, the proportion of patients who achieved the SCB ranged from 49% to 56%, and the proportion of patients who achieved the PASS threshold ranged from 55% to 79%. Among the cohort for defining MCID, SCB, and PASS, the proportion of patients achieving any MCID, SCB, or PASS was 79%, 66%, and 81%, respectively. Among the sample for assessing the proportion of patients achieving a clinically meaningful threshold, the proportion achieving any MCID, SCB, or PASS threshold was 74%, 58%, and 72%, respectively.

CONCLUSION

We found that using a sample of patients undergoing PAO, the anchor-based values for the MCID and SCB were generally larger than previous distribution- and anchor-based scores that have been defined for hip preservation, whereas PASS threshold scores were similar. All MCID and SCB thresholds exceeded corresponding MDC values, confirming these scores to be valid estimates. These metrics provide more rigorous, procedure-specific definitions for the evaluation of treatment success and failure after PAO. As anchor-based metrics are defined based on patients' perceptions, they should be used preferentially for postoperative assessment over distribution-based scores.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Editorial Commentary: Arthroscopic Treatment of Mild Hip Dysplasia Can Result in Excellent Outcome and Avoid More Invasive Periacetabular Osteotomy

Several mechanisms either support or decrease stability of the hip joint. Primary stability of the hip comes from bony coverage of the femoral head, influenced by acetabular version and femoral antetorsion. In addition, soft tissue structures, such as the acetabular labrum, the ligamentum teres, and the hip capsule play a significant role in maintaining joint stability. Untreated hip instability may lead to pathological force transmission between the acetabular socket and femoral head, and subluxation resulting in osteoarthritis. Historically, pelvic and/or femoral osteotomies have been performed to increase hip stability and prevent joint degeneration. However, osteotomies do not address soft tissue instability or lesions of intra-articular structures, which could explain symptoms following bony correction. Furthermore, the rate of combined pathologies resulting in hip instability and femoroacetabular impingement syndrome (FAIS) is high. Modern hip arthroscopy enables reconstruction and stabilization of soft tissue structures and the correction of bony pathologies caused by FAIS. Minimally invasive procedures can help avoid overtreatment and unnecessary risks associated with more invasive osteotomies. However, in cases of ongoing symptoms after arthroscopic treatment for mild instability, or for patients with severe dysplasia, concomitant PAO and arthroscopy can combine bony correction of a PAO with intra-articular therapies of hip arthroscopy.

Painful Borderline Acetabular Dysplasia: What's New?

Developmental dysplasia of the hip (DDH) is a complex static-dynamic condition resulting in chronic joint instability and osteoarthritis. Borderline acetabular dysplasia refers to slightly abnormal patterns in the acetabular shape and coverage that are not within the dysplastic range. However, they can predispose to mechanical dysfunction and hip instability. Diagnosis and treatment remain controversial topics in hip preservation, with little current comparative literature to guide accurate diagnosis and treatment decision-making. Historically, the diagnosis of borderline DDH relied on assessments of the acetabular anatomy on anteroposterior pelvic radiography, most commonly the lateral central-edge angle (LCEA), with normal values ranging from 20 to 25° or, in some more recent studies, 18 to 25°. Surgical treatment decision-making debates the use of isolated hip arthroscopy or periacetabular osteotomy, considering the difficulty in determining a fundamental mechanical diagnosis (instability versus femoroacetabular impingement) in subjects with borderline DDH. Therefore, for effective surgical decision-making, the evaluation of additional bone anatomy characteristics, instability, and patients' features is essential.

With Proper Surgical Indications, Sex-Based Differences in Pathology Do Not Impact Hip Arthroscopy Outcomes or Complications: A Systematic Review

PURPOSE

To identify sex-based differences in pathology, outcomes, and complications after hip arthroscopy for femoroacetabular impingement (FAI), and to compare patient-reported outcomes (PRO) scores between male and female patients.

METHODS

The PubMed and MEDLINE databases were searched in September 2024, according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Included studies had data stratified by sex, minimum 2-year PRO scores for hip arthroscopy in the setting of FAI and labral pathology, and a 2014 or later publication date. Patient demographic information, preoperative radiographic measurements, and surgical procedure information was also recorded. PROs were recorded when discussed. Information on the minimum clinically important difference, patient acceptable symptomatic state, and substantial clinical benefit was recorded when available.

RESULTS

In total, 21 studies were included in the systematic review. The systematic review found that there are sex-based differences in preoperative characteristics, such as male patients having a significantly greater incidence of acetabular injury, larger alpha angle, complex labral tearing, and greater grade LT villar classification, leading to differences in surgical indication, and female patients being indicated for capsular repair or plication at a greater frequency. There was a significant heterogeneity between male and female patients for preoperative modified Harris Hip Score (mHHS) (male: 55.7-83; female: 49-64.45; I2 = 0.78), Non-Arthritic Hip Score (NAHS) (male: 62.54-78.1; female: 47.2-66; I2 = 0.77), Hip Outcome Score-Sport-Specific Subscale (HOS-SSS) (male: 46.72-52.3; female: 22.8-45.7; I2 = 0.96), as well as postoperative HOS-SSS (male: 72.2-91; female: 62.6-82.4; I2 = 0.66). Despite these differences, both male and female patients experienced similar magnitudes of improvement for mHHS (male: 13-20.14; female: 20.6-30.2; I2 = 0.00), NAHS (male: 18-19.93; female: 18.75-33.5; I2 = 0.00), and HOS-SSS (male: 27.7-31.4; female: 26.75-39.8; I2 = 0.42), as well as postoperative scores for mHHS (male: 82.445-96; female: 79.2-89.6; I2 = 0.00) and NAHS (male: 82.445-94.5; female: 81.2-89.2; I2 = 0.00). No differences were consistently identified in regard to survival rates and complications.

CONCLUSIONS

Male and female patients present with different preoperative characteristics that affect surgical treatment. With proper surgical indication, both male and female patients achieve significant postoperative improvement after hip arthroscopy and demonstrate comparable survival rates.

LEVEL OF EVIDENCE

Level IV, systematic review of Level II-IV studies.

Borderline Hip Dysplasia - Best Treated with Hip Arthroscopy or Periacetabular Osteotomy?

PURPOSE OF REVIEW

As the field of hip preservation evolves, the diagnosis of borderline dysplasia (defined as a lateral center edge angle between 18°-25°) has shown itself to be one of the more challenging diagnoses to treat. As the nuances of acetabular coverage have come to light, the question of whether borderline hip dysplasia is best treated with isolated hip arthroscopy, periacetabular osteotomy, or whether a combined procedure is best, is now top of mind. The goal of these procedures is to not only improve patient symptoms, but to correct underlying pathology and ideally slow the development of hip osteoarthritis. The purpose of this review is to summarize the recent literature and clinical findings regarding both isolated hip arthroscopy and periacetabular osteotomy in the surgical management of borderline hip dysplasia.

RECENT FINDINGS

Current research demonstrates improved postoperative clinical outcome scores for both patients who had isolated hip arthroscopy in the setting of borderline hip dysplasia and for those patients who underwent periacetabular osteotomy. Mid-term outcomes for patients in both groups have showed low rates of conversion to total hip arthroplasty. No gold standard in the surgical management of borderline hip arthroscopy exists. Improved clinical outcomes have been seen postoperatively in patients who undergo hip arthroscopy and in patients who undergo periacetabular osteotomy. Successful clinical outcomes seem to rely on treatment of the underlying clinical pathology and are largely based on the appropriate surgical indications and appropriate surgical techniques. Surgical decision making in this patient population should be individualized based on a comprehensive evaluation of the patient.

Comparing outcomes of hip arthroscopy and periacetabular osteotomy for the treatment of borderline hip dysplasia: a systematic review

Hip arthroscopy (HA) and periacetabular osteotomy (PAO) are common hip preservation procedures pursued in borderline hip dysplasia (BHD), yet there is no consensus on the preferred treatment. This systematic review aims to synthesize the present literature on HA and PAO for the management of BHD. A review of multiple electronic databases was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. All studies that reported outcomes of patients with BHD treated by PAO or HA with capsular closure were included. PROs, complications, and rates of subsequent surgery were evaluated. A total of 14 studies met criteria for inclusion. Eight reported outcomes following PAO and seven reported outcomes following HA. One study reported outcomes of both procedures. Both PAO and HA studies demonstrated significant improvement in PROs. Complication rates in PAO patients ranged from 0% to 7.8% compared to 0% in HA patients. Total hip arthroplasty (THO) conversion rates in PAO patients ranged from 0% to 10.5% compared to 0% to 23.7% in HA patients. Hardware removal was performed in 25-51% of PAO patients. PAO conversion following failed HA occurred in 0-6.1% of patients. Rates of other reoperation (excluding hardware removal) in PAO patients ranged from 0% to 22.2% compared to 0% to 7.9% in HA patients. Based on the current evidence, both PAO and HA demonstrate significant improvement in PROs with a low conversion rate to THA, yet additional long-term follow-up studies are required.

Staged Hip Arthroscopy and Periacetabular Osteotomy in Active Patients Aged 45 Years and Older Produce Comparable Improvements in Outcome Scores to Younger Patients

PURPOSE

To determine staged hip arthroscopy and periacetabular osteotomy (PAO) mid-term outcomes in active patients aged 45 years and older compared with a younger group.

METHODS

All patients aged 45 years and older who underwent staged arthroscopy and PAO between 2015 and 2021 were retrospectively analyzed and compared with a case-matched control group of younger patients. All patients underwent at least 6 months of nonoperative management prior to surgery. Prior to PAO, all patients underwent hip arthroscopy to address any intra-articular pathology. The experimental group consisted of patients with dysplasia aged 45 years and older without significant osteoarthritis who underwent PAO and reported patient-reported outcomes for a minimum of 1 year postoperatively. Patient-reported outcomes were quantified using the International Hip Outcome Tool 12 (iHOT-12) score and Non-arthritic Hip Score (NAHS).

RESULTS

The cohort consisted of 35 patients (44 hips) with a mean age of 49.4 ± 3.8 years. The lateral center-edge angle significantly improved from preoperatively (20.1° ± 4.5°) to postoperatively (33.2° ± 3.2°, P < .001). The mean follow-up period in the PAO cohort aged 45 years and older was 2.80 years (standard deviation, 1.3 years) postoperatively. Patients reported significant improvements in the iHOT-12 score (36.6 ± 14.1 preoperatively vs 81.2 ± 21.0 at latest follow-up, P < .001) and NAHS (59.2 ± 15.5 preoperatively vs 87.4 ± 13.1 at latest follow-up, P < .001). The older cohort did not report significantly different iHOT-12 scores compared with the control group at any point, and age did not significantly affect either outcome score (P > .05).

CONCLUSIONS

Patients aged 45 years and older reported a statistically significant improvement in hip function and pain after staged hip arthroscopy and PAO, with outcome scores comparable to a younger cohort. Our findings show that appropriately selected older patients with dysplasia without significant pre-existing hip osteoarthritis experience clinically meaningful improvements in hip pain and function after hip preservation surgery.

LEVEL OF EVIDENCE

Level III, retrospective, comparative case series.

Persistence of Labral Tears and Resolution of Paralabral Cysts With 2-Year Magnetic Resonance Imaging Analysis After Periacetabular Osteotomy for Hip Dysplasia

PURPOSE

To evaluate the labrum status and paralabral cysts on preoperative and postoperative magnetic resonance imaging (MRI) in patients with developmental dysplasia of the hip (DDH) who underwent periacetabular osteotomy (PAO).

METHODS

A retrospective review was conducted using prospectively collected data from patients who had undergone primary PAO between June 1, 2021, and May 30, 2022. Inclusion criteria were an age range of 16 to 55 years and a minimum follow-up of 2 years. MRI was used to evaluate the preoperative and postoperative conditions of the labrum and the presence of paralabral cysts. Furthermore, the correlations between the presence of paralabral cysts and demographic and radiographic variables were investigated. Additionally, patient-reported outcomes (PROs), minimal clinically important difference, and complications were reported during the final follow-up evaluation.

RESULTS

A total of 23 patients were included in the final analysis, with an average follow-up of 26.6 ± 3.4 months (range, 24-32 months). All patients diagnosed with symptomatic DDH exhibited labrum tears. MRI scans revealed paralabral cysts in 10 of 24 (41.6%) patients, with a significant correlation noted between the presence of cysts and preoperative lateral center-edge angle (ρ = -0.649; P = .001), anterior center-edge angle (ρ = -0.637; P = .001), Tönnis angle (ρ = 0.593; P = .002) and age (ρ = -0.444; P = .034). Postoperative MRI scans at 1 year showed resolution of all paralabral cysts, while labral tears were found to persist. At the end of the follow-up period, most patients improved considerably in PROs compared with preoperative values. The probabilities of achieving the minimal clinically important difference were 91.3% on the Hip Outcome Score-Activities of Daily Living, 78.2% on the Hip Outcome Score-Sports Subscale, 91.3% on the modified Harris Hip Score, 73.9% on the International Hip Outcome Tool 12-component form, and 69.6% on the visual analog scale pain scale.

CONCLUSIONS

All symptomatic patients with DDH had labral tears and a high prevalence of paralabral cysts, which were corrected with reduced acetabular coverage. After PAO surgery, patients experienced notable enhancements in PROs, with resolution of paralabral cysts but persistence of labral tears.

LEVELS OF EVIDENCE

Level Ⅳ, retrospective case series.

Risk Factors for Failure of Hip Arthroscopy in Patients With Borderline Dysplasia Include a Tönnis Angle ≥15°, Age ≥40 to 42 Years, Female Sex, Anterior Wall Index <0.35, Labral Debridement, and Preexisting Hip Osteoarthritis: A Systematic Review

PURPOSE

To systematically review the literature to determine potential risk factors for failure of hip arthroscopy (HA) in patients with borderline hip dysplasia (BHD).

METHODS

A systematic review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines by searching PubMed, the Cochrane Library, and Embase to identify English-language clinical studies reporting on patients with BHD undergoing HA from 2003 to 2023. The search terms used were (borderline OR mild) AND hip AND (arthroscopy OR dysplasia) AND failure. The primary outcomes assessed were risk factors reported by each study for failure of a HA-only approach in patients with BHD.

RESULTS

Fourteen studies (8 Level III, 6 Level IV) met inclusion criteria, totaling 749 hips. Patient age ranged from 29.8 to 39.2 years, with a mean follow-up ranging from 24.0 to 144.0 months. The overall percentage of female patients ranged from 11.8% to 100.0%. Overall, the clinical failure rate ranged from 0 to 53.3%, and the reoperation rate ranged from 0 to 44.0%. The predominant predictors of poor outcomes after HA alone included Tönnis angle ≥15°, age ≥40 to 42 years at surgery, and female sex. Other risk factors for failure were preoperative clinical arthritis, grade 3 or 4 articular cartilage changes to the femoral head or acetabulum, an anterior wall index <0.35, and labral debridement. Revision procedures performed included revision HA (n = 88, 0-28.0%), total hip arthroplasty (n = 55, 0%-23.7%), and endoscopic shelf acetabuloplasty (n = 5, 0%-11.0%). One study included an additional 9 patients converting to either periacetabular osteotomy or total hip arthroplasty without distinguishing between the two.

CONCLUSIONS

For patients with BHD, Tönnis angle ≥15°, age ≥40 to 42 years at surgery, female sex, anterior wall index <0.35, labral debridement, and pre-existing hip osteoarthritis are common risk factors for treatment failure following isolated HA.

LEVEL OF EVIDENCE

Level IV, systematic review of Level III-IV studies.

How useful are indirect radiographic measurements of hip instability in borderline hip dysplasia? An MRI-based comparison to a healthy cohort

PURPOSE

Symptomatic hips with borderline hip dysplasia (BHD) morphology pose a challenge in differentiating stable from unstable hips. The current study aims to compare indirect radiographic signs of instability in a symptomatic BHD population to those in a healthy cohort.

METHODS

The study group consisted of patients with a lateral centre-edge angle (LCEA) with values 18° ≤ LCEA < 25° who underwent corrective periacetabular osteotomy (PAO) and reported an improvement in patient-reported outcome measures (PROMs). The comparison group consisted of a healthy cohort of athletes who did not complain of any hip-related symptoms and who had normal values of their hip morphological parameters (LCEA, acetabular index (AI°), alpha angle (α°), femoral version, acetabular version). Indirect signs of instability consisting of the femoro-epiphyseal acetabular roof index (FEAR), iliocapsularis-to-rectus-femoris (IC/RF) ratio and labral dimensions (height-to-length ratio) were assessed in both groups. Partial Pearson correlation, logistic multiple regression analysis and Receiver-Operating Characteristic (ROC) curve analysis were performed to determine correlations, as well as the sensitivity and specificity of these signs to differentiate between healthy hips and BHD.

RESULTS

On binary logistic multiple regression analysis, the FEAR Index was the only independent predictor to differentiate between BHD and healthy hips (p < 0.001). The IC/RF ratio did not achieve significance. The calculated area under the curve (AUC) was 0.93 (0.87 - 0.99, CI 95%, p < 0.001) for the FEAR Index and 0.81 (0.70 - 0.92, CI 95%, p < 0.001) for the height-length ratio. Using the predefined cut-off values (dysplastic-FEAR Index ≥ 5° or labral height-to-length ratio ≤ 0.5), 27% sensitivity/100% specificity and 20% sensitivity/ 100% specificity, were achieved. ROC analysis provided the following new thresholds: FEAR Index ≥ -5° (73% sensitivity/97% specificity); labral height-to-length ratio ≤ 0.8 (70% sensitivity, 79% specificity).

CONCLUSION

In our cohort, the FEAR index was an independent parameter that could differentiate between borderline dysplastic and asymptomatic hips. The previously published values for both the FEAR index and labral hypertrophy ratio had a poor sensitivity in differentiating symptomatic unstable BHD from healthy hips. The cut-off values of ≥ -5° (FEAR index) and ≤ 0.8 (labral height-to-length ratio) provided acceptable sensitivity and specificity when comparing to morphological healthy hips.

Borderline Developmental Dysplasia of the Hip With Osseous Impingement as Distinct From Femoroacetabular Impingement and Developmental Dysplasia of the Hip

Background

Borderline developmental dysplasia of the hip (BDDH) accompanied by cam deformity and subspinous impingement has been found to benefit from arthroscopic surgery. However, the research comparing BDDH combined with osseous impingement to femoroacetabular impingement (FAI) without borderline dysplasia remains limited.

Purpose/Hypothesis

To compare the clinical symptoms, intraoperative findings, and outcomes of hip arthroscopy in patients with BDDH and osseous impingement versus cam-type FAI. It was hypothesized that BDDH with osseous impingement could be classified as a distinct entity between FAI and developmental dysplasia of the hip (DDH).

Study Design

Cohort study; Level of evidence, 3.

Methods

Data were collected from patients 18 to 50 years old who underwent primary hip arthroscopy between September 2016 and October 2020. Patients were divided based on preoperative lateral center-edge angle (LCEA) into 2 groups: (1) BDDH group (LCEA 18°-25°; n = 67); and (2) cam-type FAI group without BDDH (FAI group; LCEA 25°-40° and alpha angle >55°; n = 145). Disparities in symptoms, preoperative examination, intraoperative findings and procedures, and patient-reported outcome (PRO) scores were compared.

Results

Follow-up was available for 61 (91.0%) patients in the BDDH group and 125 (86.2%) patients in the FAI group. The incidence of cam deformity in BDDH patients was 91.8%. The preoperative characteristics and intraoperative findings were similar between the groups; however, preoperative internal and external hip rotation, Tönnis angle, femoroepiphyseal acetabular roof index, labral size, capsule thickness, and percentage of ligamentum teres tear were significantly higher in the BDDH group than the FAI group, and the percentage of pain aggravating factor, cam deformity, and anterior inferior iliac spine types 2 and 3 were also significantly different between groups (P < .05 for all). The percentage of intraoperative minimal acetabuloplasty, subspinous decompression, labral repair, ligamentum teres debridement, and capsular closure was significantly higher in the BDDH group than the FAI group, while the percentage of femoroplasty was higher in the FAI group (P < .05). Pre- to postoperative improvement on PRO scores was seen in both groups.

Conclusion

Given the differences in etiology and surgical procedures between the 2 conditions, it is suggested that BDDH with osseous impingement be classified as an entity distinct from FAI and DDH (and separate from BDDH without impingement) while excluding joint instability.

Femoro-Epiphyseal Acetabular Roof Index Values on Anteroposterior Pelvic Radiographs Significantly Increase With Hip Adduction and Decrease With Abduction

PURPOSE

To investigate the impact of hip adduction and abduction on the femoro-epiphyseal acetabular roof (FEAR) index using conventional anteroposterior pelvic radiographs of patients with borderline hip dysplasia (BHD).

METHODS

Patients with BHD (lateral center edge angle [LCEA] with values of 18° ≤ LCEA <25°) and who were subject to periacetabular osteotoym were selected from a consecutive retrospective cohort from January 2009 to January 2016. The hip ad-/abduction (adduction handled as negative values) and the FEAR index (lateral opening angles handled as positive values) were measured in the initially standardized acquired pelvic radiographs. Thereafter, using surgical planning software, different degrees of hip adduction and abduction were simulated from 20° of adduction to 30° of abduction, and the FEAR index was measured at each position. Pearson correlation was used to identify a potential correlation between the hip ad-/abduction and the FEAR index.

RESULTS

Eighty-nine hips were included. Initial radiographs showed unintentional mean ad-/abduction of -5.3° ± 3.1° (range, -14° to 2°). The mean FEAR index at the initial ad-/abduction angle was -3.6° ± 7.2° (range, -18.0° to 16.0°) and was significantly different from neutral position (0° of ad-/abduction) -9.2° ± 7.0° (range, -27.0° to 10.0°) (P < .001). The FEAR index was negatively correlated to the hip ad-/abduction angle (r = 1, P < .001), with lower values for the FEAR index with the hip in abduction.

CONCLUSIONS

Significant differences in FEAR index measurements were observed depending on hip ad-/abduction on pelvic radiographs. A linear change of the FEAR index of 5° per 5° of hip adduction or abduction could be demonstrated, with adduction resulting in increasing and abduction in decreasing values for the FEAR index.

LEVEL OF EVIDENCE

Level III, diagnostic study.

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.

Outcomes of Flexibility Sport Athletes With Borderline Hip Dysplasia After Hip Arthroscopy for Femoroacetabular Impingement Syndrome: A Propensity-Matched Analysis at Minimum 2-Year Follow-up

BACKGROUND

Hip arthroscopy has proved successful in treating femoroacetabular impingement syndrome (FAIS) in patients with and without borderline hip dysplasia (BHD). Despite a high prevalence of BHD in patients who participate in sports with high flexibility requirements, a paucity of literature evaluates the efficacy of hip arthroscopy in treating FAIS in flexibility sport athletes with BHD.

PURPOSE

To compare minimum 2-year patient-reported outcomes (PROs) and achievement of clinically significant outcomes in flexibility sport athletes with BHD undergoing primary hip arthroscopy for FAIS with capsular plication with results in flexibility sport athletes without dysplasia.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Data were prospectively collected for patients undergoing primary hip arthroscopy for FAIS with BHD, defined as a lateral center-edge angle of 18° to 25°, who reported participation in a sport with a high flexibility requirement, including dance, gymnastics, figure skating, yoga, cheerleading, and martial arts, according to previous literature. These patients were matched 1:2 to flexibility sport athletes without dysplasia, controlling for age, sex, and body mass index. Preoperative and minimum 2-year postoperative PROs were collected and compared between groups. Cohort-specific minimal clinically important difference and patient acceptable symptom state achievement was compared between groups.

RESULTS

In total, 52 flexibility sport athletes with BHD were matched to 104 flexibility sport athletes without BHD. Both groups showed similar sport participation (P = .874) and a similar level of competition (P = .877). Preoperative lateral center-edge angle (22.2°± 1.6° vs 31.5°± 3.9°; P < .001) and Tönnis angle (10.9°± 3.7° vs 5.8°± 4.4°; P < .001) differed between groups. Capsular plication was performed in all cases. Both groups achieved significant improvement in all PROs (P < .001) with no differences in postoperative PROs between groups (P≥ .147). High minimal clinically important difference (BHD group: 95.7%; control group: 94.8%) and patient acceptable symptom state (BHD group: 71.7%; control group: 72.2%) achievement for any PRO was observed with no differences between groups (P≥ .835).

CONCLUSION

Flexibility sport athletes with BHD achieved similar outcomes as those of flexibility sport athletes without BHD after hip arthroscopy for FAIS with capsular plication.