Borderline Dysplasia Research Articles

Deep learning-based automated measurement of hip key angles and auxiliary diagnosis of developmental dysplasia of the hip.

Anteroposterior pelvic radiographs remains the most widely employed method for diagnosing developmental dysplasia of the hip. This study aims to evaluate the accuracy of an artificial intelligence model in measuring angles in pelvic radiographs of the hip. The assessment seeks to demonstrate the efficacy of the artificial intelligence model in diagnosing both developmental dysplasia of the hip and borderline developmental dysplasia of the hip through the analysis of pelvic radiographs. A total of 1,029 patients, including 273 men and 757 women, were retrospectively included in this study. The anteroposterior pelvic radiographs were randomly divided into three sets: the training set (720 cases), the validation set (103 cases), and the test set (206 cases). Key anatomical points on the anteroposterior pelvic radiographs were identified. The Sharp, Tönnis, and Center Edge angles were calculated automatically based on the corresponding criteria. The hip development status was compared between measurements obtained from the artificial intelligence model and those defined manually by two radiologists. The area under the receiver operating characteristic curve was utilized to assess the diagnostic performance of the artificial intelligence model. The results obtained from both manual measurements and the artificial intelligence model demonstrated no significant differences in the Sharp, Tönnis, and Center edge angles (all p > 0.05). The intra-class correlation coefficients and correlation coefficient r values exceeded 0.75, indicating that both the artificial intelligence model and manual measurements exhibited good repeatability and a positive correlation. Notably, the artificial intelligence model provided measurements more faster than those conducted by radiologists (p = 0.001). The artificial intelligence model also demonstrated high diagnostic accuracy, sensitivity, and specificity for developmental dysplasia of the hip. The performance of the artificial intelligence model in diagnosing developmental dysplasia of the hip was robust. Additionally, the results from the artificial intelligence model and manual measurements were largely consistent with clinical diagnosis results (p = 0.01). The artificial intelligence model can effectively evaluate hip conditions by measuring the Sharp, Tönnis, and Center edge angles, which are consistent closely with clinical diagnosis results. The results of the artificial intelligence model measurements demonstrate a high degree of consistency with those obtained through manual measurements. The angles of Sharp, Tönnis, and Center edge, as evaluated by the deep learning-based convolutional neural network model, exhibit robust diagnostic performance in identifying both developmental dysplasia of the hip and borderline developmental dysplasia of the hip. Consequently, the artificial intelligence model has the potential to fully replace manual measurements of these critical hip angles, providing a more efficient and precise alternative for diagnosing both conditions of the hip.

Radiographs Underestimate Lateral Center Edge Angle and Tonnis Angle Measurements Compared to CT Scan in Assessment of Borderline and Frank Acetabular Dysplasia

Radiographs Underestimate Lateral Center Edge Angle and Tonnis Angle Measurements Compared to CT Scan in Assessment of Borderline and Frank Acetabular Dysplasia

Hip shelf acetabuloplasty in borderline dysplasia, an alternative between Periacetabular Osteotomy and arthroscopic procedures.

Surgical treatments for symptomatic borderline dysplastic hips (Lateral Center-Edge Angle: LCEA 18-25°) remain challenging, instability being the primary issue. Currently, treatment options include arthroscopic procedures or peri-acetabular osteotomy (PAO). Although the popularity of the acetabular shelf bone block has declined in favor of PAO, it may still be relevant as a hip joint stabilizer and coverage area, rather than for increasing coverage area by cartilage. We analyzed clinical and radiographic outcomes of 23 borderline hips after undergoing shelf procedure with a minimum follow-up of two years. This is a retrospective descriptive study. Clinical evaluations (modified Harris Hip Score: mHHS, Non-Arthritic Hip Score: NAHS, International Hip Outcome Tool: iHOT12) and radiographic assessments were performed before and after surgery. We collected data on revision surgery rates, associated surgical procedures (labrum, impingement), complications, arthrosis progression, and conversion to total hip replacement (THR). The mean LCEA was 21°, and the mean follow-up period was five years (2 to 14 years). Clinical scores showed significant improvement at the last follow-up, mHHS increasing from 47 to 72 (p < 0.001), NAHS from 42 to 68 (p < 0.001), iHOT12 from 28 to 52 (p < 0.001), and pain levels decreasing from 7 to 3. Revision surgery rate was 13%, and complication rate was 8%. No osteoarthritis beyond Tönnis grade 2, and no cases required conversion to THR. Arthroscopic procedures and PAO have shown promising results in the treatment of borderline hips. The hip shelf procedure appears to be a simple and effective treatment for stabilizing borderline hips, with favorable outcomes for 80% of patients and a low rate of arthritic progression. Shelf procedure could be a valuable addition to the therapeutic options for painful borderline dysplasia of the hip.

Clinical Outcomes of the Arthroscopic Capsular Suture-Lifting Technique in the Treatment of Femoroacetabular Impingement in Patients With Borderline Developmental Dysplasia of the Hip.

Patients with femoroacetabular impingement (FAI) are likely to present with borderline developmental dysplasia of the hip (BDDH). Considering the prolonged risk of negative prognosis in these patients, the need for surgical management of the capsule has been emphasized. Although previous studies have advocated different techniques of capsular closure during surgery, no consensus has been achieved. Therefore, the aim of this study was to evaluate the clinical outcomes of a new arthroscopic capsular suture-lifting technique for the treatment of FAI combined with BDDH. The arthroscopic capsular suture-lifting technique would achieve better anterior stability and show better clinical outcomes compared with routine capsular closure. Cohort study; Level of evidence, 3. Consecutive patients diagnosed with FAI and BDDH and who underwent hip arthroscopy in our hospital between September 1, 2017, and April 30, 2021, were evaluated. Data were collected prospectively and analyzed retrospectively. Patients were divided into 2 groups according to the capsule closure methods used: capsular suture-lifting technique (lifting group) and routine capsular closure (control group). Anteroposterior hip radiography, Dunn view radiography, and computed tomography imaging were carried out for all patients preoperatively and postoperatively. Patient-reported outcomes, including the modified Harris Hip Score (mHHS) and visual analog scale (VAS) for pain, were collected preoperatively and at least 1 year after surgery and compared between the 2 groups. The Wilcoxon signed-rank test was used to evaluate changes in preoperative to postoperative mHHS scores and VAS. Mann-Whitney U test was used to evaluate significant differences in postoperative mHHS and VAS scores in the 2 groups. In all, 144 patients were included in this study, of whom 77 (53.5%) underwent the arthroscopic capsular suture-lifting technique and 67 (46.5%) underwent routine arthroscopic surgery. The patients in both groups had significant improvement in postoperative mHHS and VAS compared with the preoperative assessment (P < .05). The postoperative VAS score of patients in the suture-lifting group was significantly lower (2.6 vs 3.8; P < .05) and the mHHS score was significantly higher (75.2 vs 68.5; P < .05) than those of patients in the control group. Of the 77 patients in the suture-lifting group, 68 (88.3%) surpassed the minimal clinically important difference (MCID) and 49 (63.6%) achieved the Patient Acceptable Symptom State (PASS). Of the 67 patients in the control group, 26 (38.8%) surpassed MCID and 32 (47.8%) achieved PASS. The percentage of patients achieving MCID and PASS in the suture-lifting group was significantly greater than that in the control group (P = .007 for MCID; P = .03 for PASS). The study demonstrated that the arthroscopic capsular suture-lifting technique provided good clinical outcomes in the treatment of patients with FAI combined with BDDH. This technique showed better improvement of postoperative clinical outcomes than routine capsular closure.

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

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. 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

Abstract 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.

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

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

Radiological predictors of outcomes in hip arthroscopy for femoroacetabular impingement.

Hip arthroscopy has gained prominence as a primary surgical intervention for symptomatic femoroacetabular impingement (FAI). This study aimed to identify radiological features, and their combinations, that predict the outcome of hip arthroscopy for FAI. A prognostic cross-sectional cohort study was conducted involving patients from a single centre who underwent hip arthroscopy between January 2013 and April 2021. Radiological metrics measured on conventional radiographs and magnetic resonance arthrography were systematically assessed. The study analyzed the relationship between these metrics and complication rates, revision rates, and patient-reported outcomes. Out of 810 identified hip arthroscopies, 359 hips were included in the study. Radiological risk factors associated with unsatisfactory outcomes after cam resection included a dysplastic posterior wall, Tönnis grade 2 or higher, and over-correction of the α angle. The presence of acetabular retroversion and dysplasia were also significant predictors for worse surgical outcomes. Notably, over-correction of both cam and pincer deformities resulted in poorer outcomes than under-correction. We recommend caution in performing hip arthroscopy in patients who have three positive acetabular retroversion signs. Acetabular dysplasia with a lateral centre-edge angle of less than 20° should not be treated with isolated hip arthroscopy. Acetabular rim-trimming should be avoided in patients with borderline dysplasia, and care should be taken to avoid over-correction of a cam deformity and/or pincer deformity.

Poster 210: Flexible Athletes with Borderline Hip Dysplasia Achieve Successful and Similar Outcomes after Hip Arthroscopy Compared to Flexible Athletes without Borderline Hip Dysplasia

Objectives: To compare minimum 2-year patient-reported outcomes and achievement of clinically significant outcomes in flexibles athletes with and without borderline hip dysplasia (BHD) undergoing primary hip arthroscopy for femoroacetabular impingement syndrome (FAIS) with capsular plication. Methods: Data was prospectively collected for patients undergoing primary hip arthroscopy for FAIS with borderline hip dysplasia (BHD), defined as a lateral center edge angle (LCEA) of 18° to 25°, with primary participation in a sport with high flexibility requirement including dance, gymnastics, figure skating, yoga, cheerleading, and martial arts. These patients were matched 1:2 to flexible athletes with an LCEA &gt;25° controlling for age, sex, body mass index (BMI) and follow up duration. Preoperative and minimum 2-year postoperative patient-reported outcomes included: Hip Outcome Score (HOS) Activities of Daily Living, HOS Sports Scale, International Hip Outcome Score 12, modified Harris Hip Score, and Visual Analog Scale for Pain. Cohort-specific Minimal Clinically Important Difference (MCID) and Patient Acceptable Symptom State (PASS) were calculated and compared between groups. Results: Fifty-two flexible athletes with BHD were matched to 104 flexible athletes without BHD. Similar sport participation (45% dance vs. 41%, p=0.874) and level of competition (74% vs. 74% recreational, p=0.877) were observed. Preoperative LCEA (22.2° ± 1.6 vs. 31.5° ± 3.9, p &lt; 0.001) and Tönnis angle (10.9 °± 3.7 vs. 5.8° ± 4.4, p &lt; 0.001) differed significantly between groups. Capsular plication was performed in all cases (100% and 100%, p = 1.000). Both groups achieved significant improvement in all PROs (p ≤ 0.001) with no differences in PROs between groups (p ≥ 0.147). High MCID (95.7%, 94.8%) and PASS (71.7%, 72.2%) achievement for any PRO was observed with no differences between groups (p ≥ 0.222). Conclusions: Flexible athletes with BHD achieve successful and similar outcomes to those without BHD after primary hip arthroscopy for FAIS with capsular plication.

Poster 203: Staged Hip Arthroscopy and Periacetabular Osteotomy Versus Hip Arthroscopy Alone in Patients with Borderline Hip Dysplasia: A Propensity-Matched Study

Objectives: The management of borderline hip dysplasia (BHD) remains an area of interest in the field of hip preservation. The purpose of this study was to (1) evaluate mean 2-year outcomes for patients with BHD treated with staged hip arthroscopy and periacetabular osteotomy (PAO) to those who underwent hip arthroscopy alone, and (2) evaluate rates of complications, hardware removal, reoperations, conversions to total hip arthroplasty (THA), along with conversions to PAO. Methods: Hips with a lateral center-edge angle (LCEA) values 18° ≤ LCEA &lt; 25° that underwent a hip arthroscopy for femoroacetabular impingement syndrome (FAIS) between January 2018 and June 2022 were reviewed. Patients who underwent staged periacetabular osteotomy and hip arthroscopy were identified. Staged hips were propensity-matched 1:4 to other borderline dysplastic hips that underwent hip arthroscopy alone. Matching was performed based on age, sex, and body-mass index (BMI). Patient-reported outcomes (PROs) were collected, including Hip Outcome Score – Activities of Daily Living (HOS-ADL), HOS-Sports Specific (HOS-SS) subscale, 12-item International Hip Outcome Tool (iHOT-12) questionnaire, Patient-Reported Outcomes Measurement Information System-Pain Interference (PROMIS-PI) subscale, and PROMIS-Physical Function (PROMIS-PF) subscale. Cohort-specific minimal clinically important difference (MCID) and Patient Acceptable Symptom State (PASS) thresholds were calculated. Postoperative PROs, rates of MCID/PASS achievement, and rates of reoperation and conversion to THA were compared. Results: Twenty-four patients who underwent staged hip arthroscopy and PAO were successfully matched to 96 patients who underwent hip arthroscopy alone. Both groups were similar in terms of age, sex, and BMI. The patients who underwent a PAO had smaller LCEAs and larger Tönnis angles (21.0° vs. 23° and 11.6° vs. 9.1°, respectively). Both groups demonstrated significant improvement in PROs at minimum 1-year postoperatively (p &lt; 0.001, for all). There were no significant differences in postoperative PRO scores between the groups (p ≥ 0.223, for all). There were no significant differences in MCID/PASS achievement (p ≥ 0.224. for all). There were no reoperations or conversion to THA in the staged hip arthroscopy and PAO group. In the hip arthroscopy alone cohort, reoperation rates were 5.2% and conversion to THA occurred in 1% of the patients. There were no significant differences in secondary surgery rates between the groups (p = 1.000). Three patients in the hip arthroscopy alone group ultimately underwent PAO, 1 underwent a proximal femoral osteotomy (PFO), and one underwent a revision hip arthroscopy. These female patients were young and athletic with an LCEA &lt; 20°. Conclusions: Patients undergoing staged PAO and hip arthroplasty and isolated hip arthroplasty for treatment of BHD demonstrate similar clinical improvement. Rates of revision surgery and conversion to THA were similarly low. A small subset of patients who were initially treated arthroscopically ultimately received a PAO. This group was entirely made up of young, athletic female patients. This is encouraging early data and more long-term data is needed to evaluate the differences in survivorship. [Figure: see text]

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

IntroductionThe 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 methodsA 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.ResultsOverall, 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).ConclusionsThis 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.

Paper 46: Modern Hip Arthroscopy for FAIS Delays the Natural History of Osteoarthritis in a Fourth of Patients: A 12-Year Follow-Up Analysis

Objectives: Little is known about the impact of modern hip arthroscopy on the natural history of femoroacetabular impingement syndrome (FAIS) with respect to joint preservation. The purpose of this investigation was to (1) characterize the natural history of FAIS and (2) understand the impact of modern hip arthroscopy by radiographically comparing the hips of patients who underwent only unilateral primary hip arthroscopy with a minimum follow-up of ten years. Methods: Between 2010-2012, 619 consecutive patients were reviewed from the practice of a single fellowship-trained hip arthroscopist. Inclusion criteria were FAIS, primary unilateral hip arthroscopy (labral repair, femoroplasty, capsular closure), and minimum ten-year follow-up. The preoperative and minimum ten-year postoperative radiographs of patients were evaluated at each timepoint. Both operative and nonoperative hips were graded using the Tönnis classification or the presence of hip arthroplasty by two independent reviewers. Subgroup analyses were performed. Results: A total of 200 hips from 100 patients were available with 74% follow-up at a mean of 12.0 years were evaluated. The nonoperative hip advanced to a worse Tönnis grade in 48% (48/100) of cases compared to 28% (28/100) among operative hips (Table 1). At follow-up, Tönnis grades between hips were equal in 70% (70/100) of the cases, the operative hip had a better grade 25% (25/100) of the time, and the nonoperative hip had a better grade 5% (5/100) of the time (Table 2). Modern hip arthroscopy conferred a relative risk reduction of 42% in osteoarthritis progression. Borderline dysplasia, age, preoperative Tönnis grade, and alpha angle &gt; 65° were key risk factors in the radiographic progression of osteoarthritis. Conclusions: While the majority of patients (70%) undergoing hip arthroscopy for FAIS did not experience differences between operative and nonoperative hips in terms of the radiographic progression of osteoarthritis, the natural history was favorably altered in a quarter of patients after arthroscopic correction (Figure 1). Modern hip arthroscopy indications and techniques represent a valid joint preservation procedure conferring a relative risk reduction of 42% in the progression of osteoarthritis. Mixed patterns of impingement and instability that underwent arthroscopy were the fastest to degenerate.

Dysplastic Hips Have Decreased Iliofemoral Ligament Thickness on Coronal Sequences in Magnetic Resonance Imaging: A Matched Cohort Analysis

To characterize hip capsule thickness on advanced imaging in patients with and without hip dysplasia and to also evaluate differences in capsular thickness between patients with borderline and patients with true dysplasia. Patients evaluated by the senior author for concerns of hip pathology from June 2020 to June 2021 were queried and images reviewed to determine dysplasia status by lateral center-edge angle (LCEA) ≤25°. A group of patients without dysplasia was identified and matched for age, sex, and body mass index. Hip capsular thickness was quantified using magnetic resonance imaging. A subanalysis was conducted to compare patients with true dysplasia (LCEA < 20°) with patients with borderline dysplasia (LCEAs between 20° and 25°). The analysis included independent samples t tests, χ2 tests, and multivariable regression. A total of eighty patients were included, with a mean age of 31.8 ± 11.7 years, a mean body mass index of 26.6 ± 6.5 points, and 70% (56) female patients. Patients with dysplasia had a mean LCEA of 19.8 ± 4.3°. Patients with dysplasia had decreased capsular thickness compared with patients without dysplasia (2.75 ± 0.96 mm vs 3.52 ± 1.22 mm, P= .003). Multivariable regression showed decreased capsular thickness associated with decreased LCEAs (β= 2.804, R= 0.432, P < .001) and dysplasia (β= -0.709, R2= 0.056, P= .004). Results of a subanalysis of the dysplastic group examining differences between accepted definitions of borderline dysplasia and true dysplasia showed no significant differences in capsular thickness between the 2 groups (P= .379). Patients with hip dysplasia were found to have thinner iliofemoral ligaments in the coronal plane on magnetic resonance imaging on magnetic resonance imaging. Further investigation is needed to evaluate any potential implications with hip instability, given the thinner hip capsule demonstrated in this study. Level III, retrospective comparative prognostic trial.

Outcome Scores and Survivorship of Patients Undergoing Primary Hip Arthroscopy With Borderline Hip Dysplasia: A Propensity-Matched Study With Minimum 10-Year Follow-up

Background: Patients with borderline hip dysplasia (BHD) and concomitant femoroacetabular impingement syndrome (FAIS) have demonstrated similar outcomes at short- and midterm follow-up compared with equivalent patients without dysplasia. However, comparisons between these groups at long-term follow-up have yet to be investigated. Purpose: To compare long-term clinical outcomes between patients with BHD undergoing primary hip arthroscopy for FAIS versus matched control patients without BHD. Study Design: Cohort study; Level of evidence, 2. Methods: A retrospective cohort study was conducted on patients with BHD (lateral center-edge angle, 18°-25°) who underwent hip arthroscopy for FAIS between January 2012 and February 2013. Patients were propensity matched in a 1:3 ratio by age, sex, and body mass index to control patients without BHD who underwent primary hip arthroscopy. Groups were compared in terms of patient-reported outcomes (PROs) preoperatively and at 10 years postoperatively, including the Hip Outcome Score Activities of Daily Living subscale (HOS-ADL) and Sports subscale (HOS-SS), modified Harris Hip Score, 12-item International Hip Outcome Tool, visual analog scale (VAS) for pain and satisfaction. Achievement rates for minimal clinically important difference (MCID) and Patient Acceptable Symptom State (PASS) were compared between groups. Kaplan-Meier survivorship curves were assessed between groups. Results: At a mean follow-up of 10.3 ± 0.3 years, 28 patients with BHD (20 women; age, 30.8 ± 10.8 years) were matched to 84 controls who underwent primary hip arthroscopy. Both groups significantly improved from preoperative assessment in all PRO measures at 10 years (P < .001 for all). PRO scores were similar between groups, aside from HOS-SS (BHD, 62.9 ± 31.9 vs controls, 80.1 ± 26.0; P = .030). Rates of MCID achievement were similar between groups for all PROs (HOS-ADL: BHD, 76.2% vs controls, 67.9%, P = .580; HOS-SS: BHD, 63.2% vs controls, 69.4%, P = .773; modified Harris Hip Score: BHD, 76.5% vs controls, 67.9%, P = .561; VAS pain: BHD, 75.0% vs controls, 91.7%, P = .110). Rates of PASS achievement were significantly lower in the BHD group for HOS-ADL (BHD, 39.1% vs controls, 77.4%; P = .002), HOS-SS (BHD, 45.5% vs controls, 84.7%; P = .001), and VAS pain (BHD, 50.0% vs controls, 78.5%; P = .015). No significant difference was found in the rate of subsequent reoperation on the index hip between groups. Kaplan-Meier survival analysis demonstrated comparable survivorship at long-term follow-up (P = .645). Conclusion: After primary hip arthroscopy, patients with BHD in the setting of FAIS had significantly improved PRO scores at 10-year follow-up, comparable with propensity-matched controls without BHD. Rates of MCID achievement were similar between groups, although patients with BHD had lower rates of PASS achievement. Patients with BHD had similar long-term hip arthroscopy survivorship compared with controls, with no significant difference in rates of revision hip arthroscopy or conversion to total hip arthroplasty.

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

PurposeTo compare patient-reported outcomes (PROs), achievement of clinically significant outcomes (CSOs), 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 minimum 5-year follow-up. MethodsPatients with BHD, characterized by a lateral center-edge angle 18°-25°, who underwent HA for FAIS with capsular repair by a single surgeon between 01/2012-06/2018 with 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 (BMI). 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 (MCID), patient acceptable symptom state (PASS), and substantial clinical benefit (SCB) for any measured PRO were compared between groups along with reoperation-free survivorship using Kaplan-Meier analysis. ResultsThirty-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=0.669), sex (69.4% female vs. 70.8%,P=0.656), and BMI (25.7±4.0 kg/m2 vs. 25.5±3.7,P=0.849). The revision group showed a greater prevalence of prolonged preoperative pain (50.0% vs. 27.8%,P=0.032) compared to the primary group. A significant improvement in all PROs was observed for both groups with comparable PROs preoperatively and at 5-year follow-up between groups (P≥0.086). The revision and primary groups showed comparable MCID (95.0% vs. 95.7%,P=1.000), PASS (80.0% vs. 83.6%,P=0.757), and SCB (62.5% vs. 70.7%,P=0.603) achievement for any PRO. Comparable reoperation-free survivorship was observed (P=0.151). ConclusionPropensity-matched patients with BHD undergoing primary and revision hip arthroscopy for FAIS achieved similar minimum 5-year PROs, CSOs, and reoperation-free survivorship. Level of EvidenceLevel III, Retrospective Comparative Case Series

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

PurposeSymptomatic 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.MethodsThe 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.ResultsOn 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).ConclusionIn 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.

Noninterportal capsulotomy of hip arthroscopy showed improved outcomes in borderline hip dysplasia: A retrospective study with minimum 2-year follow-up.

The present study aimed to evaluate the functional outcomes of hip arthroscopy using a noninterportal capsulotomy technique to address labral tears in patients with borderline hip dysplasia (BHD). Additionally, we also compared these outcomes with those of patients with BHD who underwent the standard repaired interportal capsulotomy (RIPC) arthroscopy. Data from patients with BHD were retrieved from a database of patients who underwent arthroscopic hip surgery with noninterportal capsulotomy or RIPC to treat labral tears between January 2014 and December 2020. Data collected included both pre- and postoperative patient-reported outcomes (PROs). A total of 58 patients (noninterportal capsulotomy, n = 37; RIPC, n = 21) with a mean age of 30.9 ± 5.6 and 28.6 ± 5.5 years, respectively, met the inclusion criteria. All of the patients underwent a minimal 2-year follow-up. The mean lateral centre-edge angle was 23.3 ± 1.2° in the noninterportal capsulotomy group and 23.7 ± 1.0° in the RIPC group, with no significant difference. The PROs improved from the preoperative to the latest follow-up, with a p < 0.001. There were no differences between the groups. Using strict patient selection criteria, hip arthroscopy with noninterportal capsulotomy demonstrated significant pre- to postoperative improvements in patients with BHD and achieved results comparable to those from hip arthroscopy with RIPC. Level III.

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.

The Windshield Wiper Sign Is an Instability-Related Osteochondral Defect of the Anterolateral Femoral Head

PurposeTo investigate a radiographic sign believed to be indicative of hip instability and acetabular suction seal disruption in the native hip, coined the “windshield wiper” (WSW) sign. Materials and MethodsA retrospective review was performed for patients who underwent periacetabular osteotomy (PAO) with the senior author between March 2021 and September 2023. A WSW sign was identified on plain films as a concave or flat osteochondral defect on the anterolateral femoral head extending medial to the head-neck junction with resultant loss of femoral head sphericity in the native hip. Every patient underwent a standardized series of radiographs, as well as computed tomography and magnetic resonance imaging. All patients underwent arthroscopy prior to PAO to address intra-articular pathology and other indicated procedures. The osteochondral defect and resultant suction seal disruption were verified during arthroscopy. These patients were then compared with a control group of arthroscopically treated hips without hip instability. ResultsOf 250 patients reviewed, a total of 19 hips in 17 patients (prevalence of 7.6%) demonstrated radiographic evidence of the WSW sign. All patients with a WSW sign presented with symptomatic clinical hip instability requiring a PAO. The mean patient age was 31.2 years, with a mean lateral center edge angle (LCEA) of 14.3 degrees. There were 13 hips (68.4%) with dysplasia, 4 (21.1%) with borderline dysplasia, and 2 (10.5%) with a normal LCEA. All patients with a WSW sign and LCEA ≥20° displayed significant femoral antetorsion abnormalities. All arthroscopic videos and images demonstrated a compromised suction seal. Of the 50 control group hips reviewed, the WSW sign was not identified. ConclusionsThe WSW sign is an uncommon radiographic finding in patients with hip instability. When identified, it can be predictive of substantial instability, especially in cases which are otherwise considered borderline dysplasia or normal based on LCEA. Level of EvidenceIII, case-control study

Modern Hip Arthroscopy for FAIS May Delay the Natural History of Osteoarthritis in 25% of Patients: A 12-Year Follow-up Analysis.

Little is known about the effect of modern hip arthroscopy on the natural history of femoroacetabular impingement syndrome (FAIS) with respect to joint preservation. To (1) characterize the natural history of FAIS and (2) understand the effect of modern hip arthroscopy by radiographically comparing the hips of patients who underwent only unilateral primary hip arthroscopy with a minimum follow-up of 10 years. Cohort study; Level of evidence, 3. Between 2010 and 2012, 619 consecutive patients were reviewed from the practice of a single fellowship-trained hip arthroscopic surgeon. Inclusion criteria were FAIS, bilateral radiographic findings of femoroacetabular impingement, primary unilateral hip arthroscopy (labral repair, femoroplasty, or capsular closure), and minimum 10-year follow-up. The preoperative and minimum 10-year postoperative radiographs of patients were evaluated at each time point. Both operative and nonoperative hips were graded using the Tönnis classification or the presence of hip arthroplasty by 2 independent reviewers. Subgroup analyses were performed. A total of 200 hips from 100 patients were evaluated at a mean follow-up of 12.0 years. Preoperatively, 98% and 99% of operative and nonoperative hips were evaluated as Tönnis grades 0 and 1, respectively; 5% of nonoperative hips had worse Tönnis grades than operative hips. The nonoperative hip advanced to a worse Tönnis grade in 48% (48/100) of cases compared with 28% (28/100) among operative hips. At follow-up, Tönnis grades between hips were equal in 70% (70/100) of the cases, the operative hip had a better grade 25% (25/100) of the time, and the nonoperative hip had a better grade 5% (5/100) of the time. Modern hip arthroscopy was associated with a relative risk reduction of 42% in osteoarthritis progression. Impingement with borderline dysplasia, age, preoperative Tönnis grade, and alpha angle >65° were key risk factors in the radiographic progression of osteoarthritis. Although the majority of patients (70%) undergoing hip arthroscopy for FAIS did not experience differences between operative and nonoperative hips in terms of the radiographic progression of osteoarthritis, the natural history may be favorably altered for 25% of patients whose Tönnis grade was better after undergoing arthroscopic correction. Modern hip arthroscopy indications and techniques represent a valid joint-preservation procedure conferring a relative risk reduction of 42% in the progression of osteoarthritis. Arthroscopy for mixed patterns of impingement and instability were the fastest to degenerate.