Borderline Dysplasia Research Articles

Arthroscopic Treatment and Outcomes of Borderline Dysplasia With Acetabular Retroversion: A Matched-Control Study From the MASH Study Group

Background: Although acetabular retroversion (AR) occurs in dysplasia, management of the crossover sign (COS) or outcomes in borderline dysplasia (BD) with AR have not been reported. Purpose: To report any differences in the management of the COS in BD and nondysplastic hips and to report comparative outcomes of BD with AR with matched controls with BD or AR (ie, focal pincer femoroacetabular impingement [FAI]). Study design: Cohort study; Level of evidence, 3. Methods: A multicenter matched-pair study was performed with data from a large prospectively collected database. Inclusion criteria were patients who had undergone primary unilateral hip arthroscopy including labral repair for FAI and/or chondral pathology without significant osteoarthritis (ie, Tönnis grade 0 or 1). The study group (BD+AR) was defined radiographically by lateral center-edge angle (LCEA) on standing anteroposterior pelvis of 18° to 25° and positive COS. A 1:1:1 matching on age, sex, and body mass index was performed with a control group with BD and another control group with AR (LCEA, >25°+COS). Acetabuloplasty rates were determined for each group. Mean 2-year outcomes including the 12-Item International Hip Outcome Tool (iHOT-12), minimally clinical important difference (MCID), substantial clinical benefit (SCB), and Patient Acceptable Symptom State (PASS) scores were compared. Subanalysis of the study group both with and without acetabuloplasty was performed. Results: There were 69 patients, with 23 in the study group and 23 in each control group. The effect of dysplasia with or without the presence of the COS resulted in changes in acetabuloplasty rates, with 0% performed in the BD group, 35% in the BD+AR study group, and 91% in the AR group (P = .001). Arthroscopic outcomes demonstrated similar and significant mean 2-year improvement of iHOT-12 patient-reported outcomes, MCID, SCB, and PASS scores in the study and both control groups. There was a trend within the study group toward greater postoperative iHOT-12 scores in patients who received anterior-based acetabuloplasty than those who did not receive acetabuloplasty (81.7 and 70.4, respectively; P = .11). Conclusion: Acetabular coverage influences the management of the COS, with significantly lower acetabuloplasty rates in BD with AR compared with AR without BD (focal pincer impingement). Symptomatic patients with combined BD and AR had similar significant successful outcomes to those of patients with BD and those with AR (focal pincer impingement), whether treated without acetabuloplasty or, less frequently, with limited anterior-based acetabuloplasty.

Hip arthroscopy and T-shaped capsular plication for the treatment of borderline dysplasia: a minimum 2-year follow-up.

The aim of the study was to evaluate the clinical outcomes of patients treated arthroscopically for symptomatic borderline dysplasia of the hip (BHD) with a T-shaped capsular plication, with a minimum follow-up of 24 months. Twenty-seven patients who had undergone hip arthroscopy and T-shaped capsular plication for symptomatic BHD were included in the study. All patients were clinically evaluated prior to surgery (T0) and at two consecutive follow-ups (T1: 12 ± 1.2 months; T2: 52.0 ± 23.2 months) using the visual analogue scale (VAS) pain score, the Hip Outcome Score in activities of daily living (HOS-ADL) and sport-specific subscale (HOS-SSS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Short Form-12 in its physical (PCS) and mental component scores (MCS). We also evaluated the presence of correlations and analysed the possible differences between subgroups. We found a significant difference for HOS-ADL, HOS-SSS, VAS and WOMAC with the Friedman test for repeated measures through time points (p < 0.0001), but not for MCS. All clinical scores reported a significant improvement compared to the previous time point (p < 0.05), with the exception of HOS-SSS, for which p = 0.2570 between T1 and T2. The body mass index was positively correlated with preoperative VAS (R = 0.42857; p = 0.0257) and negatively correlated with PCS at T0 (R = - 0.40999; p = 0.0337) and with PCS (R = - 0.40491; p = 0.0362), MCS (R = - 0.45939; p = 0.0159) and WOMAC (R = - 0.40573; p = 0.0216) at T2. No complications were reported in our cohort. The results of the current study confirm that patients with intra-articular hip pathology and concomitant BHD (LCEA 20°-25°) can benefit from arthroscopic treatment and that T-shaped capsular plication is one of the available options. Orthopaedic surgeons specialising in hip arthroscopy should consider arthroscopy for the treatment of symptomatic BHD for stabilising and strengthening the joint. Future studies should focus on finding out which type of patients can benefit most from this procedure. Prospective Case Series.

Comparison Between Hip Arthroscopic Surgery and Periacetabular Osteotomy for the Treatment of Patients With Borderline Developmental Dysplasia of the Hip: A Systematic Review.

Background:The treatment for borderline developmental dysplasia of the hip (BDDH) has historically been arthroscopic surgery or periacetabular osteotomy (PAO). As orthopaedic surgery is constantly evolving, a lack of comparison of outcomes for these 2 treatment methods could potentially be stalling the progression of treatment for patients with BDDH.Purpose:To evaluate the existing literature on patient characteristics, procedures, clinical outcomes, and failure rates for patients with BDDH and to determine whether PAO or hip arthroscopic surgery is a better treatment method for patients with BDDH.Study Design:Systematic review; Level of evidence, 4.Methods:Studies included were found using the following search words: “hip” and “borderline dysplasia,” “osteotomy” or “arthroscopy,” and “outcome” or “procedure.” Articles were included if they detailed participants of all sexes and ages, reported on isolated hips, and had patients diagnosed with BDDH.Results:A search was conducted across 3 databases, resulting in 469 articles for consideration, from which 12 total studies (10 on arthroscopic surgery and 2 on PAO) were chosen for a review. There were 6 studies that included patients with a lateral center-edge angle of 18° to 25°, while the remainder included patients with a lateral center-edge angle of 20° to 25°. All the studies reviewing arthroscopic surgery reported concomitant/accessory procedures, while the articles on the topic of PAO did not. It was determined that, whether treated using arthroscopic surgery or PAO, outcomes improved across all patient-reported outcome measures. Revision surgery was also common in both procedures.Conclusion:There is a lack of consensus in the literature on the best treatment option for patients with BDDH. Preoperative patient characteristics and concomitant injuries should be considered when evaluating which surgical procedure will result in the most favorable outcomes.

Surgical Anatomy of the Rectus-Sparing Approach for Periacetabular Osteotomy: A Cadaveric Study.

The Bernese periacetabular osteotomy (PAO) is a widely used technique for the management of acetabular dysplasia and other hip deformities in adolescents and young adults. Originally, the approach was described with a release of both origins of the rectus femoris muscle1. In the more recently described rectus-sparing approach, both heads remain attached2,3. It has been proposed that this modification may decrease pain, ease postoperative rehabilitation, and avoid heterotopic ossifications, without limitations of the surgical overview. Both the original and the rectus-sparing approach are modifications of the Smith-Petersen approach. The skin incision and further dissection remain identical in both approaches for the protection of the lateral femoral cutaneous nerve, the osteotomy of the anterior superior iliac spine (or takedown of the inguinal ligament), the exposure of the iliac fossa, and the medial retraction of the abdominal and iliopsoas muscles. In both variants, the further dissection traverses the iliopectineal bursa. In contrast to the original approach, in which the rectus muscle becomes part of the medial flap after releasing both heads, the rectus-sparing approach involves the undetached rectus muscle becoming part of the lateral flap while the medial flap includes the sartorius and iliacus-iliocapsularis muscles. The anterior capsule and deep structures can be accessed through the interval between the rectus femoris and iliopsoas muscles or lateral to the rectus muscle. The remaining surgical steps are again similar in both techniques. According to preference, the surgeon starts with the pubic osteotomy or with the ischial cut first, the latter avoiding additional bleeding from the pubic osteotomy. For the ischial osteotomy, the bone is accessed by making an anteroposterior tunnel between the medial capsule and the iliopsoas tendon anteriorly and between the medial capsule and the obturator externus muscle posteriorly. While the ischial osteotomy is an incomplete separation, the pubic osteotomy is a complete separation. It sections the superior pubic ramus medial to the iliopectineal eminence, in a somewhat oblique fashion. The third and fourth cuts are made in the iliac bone in such a way as to keep the posterior column intact. By connecting the posterior iliac and ischial cuts as the last osteotomy step, the acetabulum is freed and repositioned as needed. The aim of our cadaver dissection is primarily to describe part of the rectus-sparing approach and to test this modification for eventual disadvantages over the classic approach. The remaining steps of the procedure correspond to the approach as described earlier1,4, appreciating that several modifications of the procedure are in use. Nonsurgical treatment may be an alternative in borderline dysplasia; however, it needs to be reconsidered and eventually changed to surgical treatment when symptoms persist or come back. Other current techniques for surgical treatment of adolescent and adult hip dysplasia include triple and rotational or spherical osteotomies5-7. The Bernese PAO is performed through a single incision. All cuts are performed from the inner side of the pelvis, avoiding interference with the vascularity of the acetabular and periacetabular bone, which mainly comes from the outside of the pelvis8. The procedure needs minimal hardware for fixation, and partial weight-bearing can be allowed. The PAO provides a wide range of acetabular reorientation options. Wide capsulotomy and intra-articular procedures are possible, as well as additional femoral corrections. Childbirth via natural delivery is possible even after bilateral PAO9. Nerve injuries can be guarded against with careful surgical execution of the osteotomies4.

Does Patient-specific Functional Pelvic Tilt Affect Joint Contact Pressure in Hip Dysplasia? A Finite-element Analysis Study.

Although individual and postural variations in the physiologic pelvic tilt affect the acetabular orientation and coverage in patients with hip dysplasia, their effect on the mechanical environment in the hip has not been fully understood. Individual-specific, finite-element analyses that account for physiologic pelvic tilt may provide valuable insight into the contact mechanics of dysplastic hips, which can lead to further understanding of the pathogenesis and improved treatment of this patient population. We used finite-element analysis to ask whether there are differences between patients with hip dysplasia and patients without dysplasia in terms of (1) physiologic pelvic tilt, (2) the pelvic position and joint contact pressure, and (3) the morphologic factors associated with joint contact pressure. Between 2016 and 2019, 82 patients underwent pelvic osteotomy to treat hip dysplasia. Seventy patients with hip dysplasia (lateral center-edge angle ≥ 0° and < 20° on supine AP pelvic radiographs) were included. Patients with advanced osteoarthritis, femoral head deformity, prior hip or supine surgery, or poor-quality imaging were excluded. Thirty-two patients (32 hips) were eligible to this finite-element analysis study. For control groups, we reviewed 33 female volunteers without a history of hip disease. Individuals with frank or borderline hip dysplasia (lateral center-edge angle < 25°) or poor-quality imaging were excluded. Sixteen individuals (16 hips) were eligible as controls. Two board-certified orthopaedic surgeons measured sagittal pelvic tilt (the angle between the anterior pelvic plane and vertical axis: anterior pelvic plane [APP] angle) and acetabular version and coverage using pelvic radiographs and CT images. Intra- and interobserver reliabilities, evaluated using the kappa value and intraclass correlation coefficient, were good or excellent. We developed individual-specific, finite-element models using pelvic CT images, and performed nonlinear contact analysis to calculate the joint contact pressure on the acetabular cartilage during the single-leg stance with respect to three pelvic positions: standardized (anterior pelvic plane), supine, and standing. We compared physiologic pelvic tilt between patients with and without dysplasia using a t-test or the Wilcoxon rank sum test. A paired t-test or the Wilcoxon signed rank test with a Bonferroni correction was used to compare joint contact pressure between the three pelvic positions. We correlated joint contact pressure with morphologic parameters and pelvic tilt using the Pearson or the Spearman correlation coefficients. The APP angle in the supine and standing positions varied widely among individuals. It was greater in patients with hip dysplasia than in patients in the control group when in the standing position (3° ± 6° versus -2° ± 8°; mean difference 5° [95% CI 1° to 9°]; p = 0.02) but did not differ between the two groups when supine (8° ± 5° versus 5° ± 7°; mean difference 3° [95% CI 0° to 7°]; p = 0.06). The mean pelvic tilt was 6° ± 5° posteriorly when shifting from the supine to the standing position in patients with hip dysplasia. The median (range) maximum contact pressure was higher in dysplastic hips than in control individuals (in standing position; 7.3 megapascals [MPa] [4.1 to 14] versus 3.5 MPa [2.2 to 4.4]; difference of medians 3.8 MPa; p < 0.001). The median maximum contact pressure in the standing pelvic position was greater than that in the supine position in patients with hip dysplasia (7.3 MPa [4.1to 14] versus 5.8 MPa [3.5 to 12]; difference of medians 1.5 MPa; p < 0.001). Although the median maximum joint contact pressure in the standardized pelvic position did not differ from that in the standing position (7.4 MPa [4.3 to 15] versus 7.3 MPa [4.1 to 14]; difference of medians -0.1 MPa; p > 0.99), the difference in the maximum contact pressure varied from -3.3 MPa to 2.9 MPa, reflecting the wide range of APP angles (mean 3° ± 6° [-11° to 14°]) when standing. The maximum joint contact pressure in the standing position was negatively correlated with the standing APP angle (r = -0.46; p = 0.008) in patients with hip dysplasia. Based on our findings that individual and postural variations in the physiologic pelvic tilt affect joint contact pressure in the hip, future studies on the pathogenesis of hip dysplasia and joint preservation surgery should not only include the supine or standard pelvic position, but also they need to incorporate the effect of the patient-specific pelvic tilt in the standing position on the biomechanical environment of the hip. We recommend assessing postural change in sagittal pelvic tilt when diagnosing hip dysplasia and planning preservation hip surgery because assessment in a supine or standard pelvic position may overlook alterations in the hip's contact mechanics in the weightbearing positions. Further studies are needed to elucidate the effect of patient-specific functional pelvic tilt on the degeneration process of dysplastic hips, the acetabular reorientation maneuver, and the clinical result of joint preservation surgery.

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

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. 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. 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. 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. III; Case-Control study.

Low Back Pain Improves After Surgery for Lesser Trochanteric–Ischial Impingement

To assess the effects of surgery for lesser trochanteric-ischial impingement (LTI) on low back pain. The records of patients with LTI who underwent endoscopic partial resection of the lesser trochanter (LT) between May of 2017 and February of 2019 were reviewed. Inclusion criteria were the presence of low back pain in association with hip pain, diagnosis of LTI, and partial resection of the LT to treat LTI. Exclusion criteria were less than 12 months of postoperative follow-up and hip or spine surgery after the LTI surgery. Patients were assessed before surgery and at the most recent follow-up with the modified Harris Hip Score and Oswestry Disability Index for lumbar spine. Thirty patients (31 hips) met the inclusion criteria. Four patients were lost to follow-up. Two patients with borderline dysplasia and grade 1 and 2 osteoarthritis underwent total hip arthroplasty after the partial resection of the LT. The results are presented considering the remaining 24 patients (25 hips). The average age at surgery was 51 years (range 32-65 years). The mean follow-up after the surgery for LTI was 19 months (range 12-35 months). The mean ± SD ODI improved from 48% ± 15 before the LTI surgery to 21% ± 22 (P < .001) at the most recent follow-up. Improvement in the Oswestry Disability Index above the minimal clinical important difference was observed in 16 patients (67%) following the LTI surgery. The mean ± SD modified Harris Hip Score improved from 55.8 ± 14 before LTI surgery to 81.3 ± 14.3 (P < .001). Decrease in low back pain above the minimal clinically important difference is observed in 2 of 3 patients after partial resection of the LT. Level IV, therapeutic case series.

Meaningful Outcomes at Five Year Following Hip Arthroscopy in Patients with Borderline Hip Dysplasia

To compare 5-year patient reported outcomes (PROMs) and rates of achieving Minimum Clinical Important Difference (MCID) and Patient Acceptable Symptomatic State (PASS) between patients with and without borderline hip dysplasia (BHD). Data from consecutive patients who underwent primary hip arthroscopy for treatment of FAIS between January 2012 and July 2014 were analyzed. Patients with BHD (LCEA=20-25 degrees) were matched 3:1 by age (+/-1 year) and BMI (+/-5) to control patients with normal acetabular coverage (LCEA=25-40 degrees). Baseline and 5-year postoperative PROMs were collected including: Hip Outcome Score-Activity of Daily Living (HOS-ADL), HOS-Sport Subscale (HOS-SS), and modified-Harris Hip Score (mHHS), along with visual analog scale (VAS) for pain and satisfaction. MCID was calculated using a distribution-based method, while PASS was calculated using an anchor-based method for the study group. PROMs, MCID, and PASS were compared among the two groups. MCID in BHD patient was defined as 10.2, 15.0, and 11.0 for HOS-ADL, HOS-SS, and mHHS, respectively. Threshold scores for achieving PASS in both groups was 91.7, 83.7, and 83.6, respectively. Sixty-five patients with 5-year PROMs were identified with having BHD and were matched to 195 controls. Both BHD and non-BHD patients saw significant increases in score averages over the 5-year period across all 3 PROMS and VAS pain. Comparison of the 5-year PROMS, VAS pain, and VAS satisfaction between the two groups did not demonstrate a statistical difference (p>0.05 for all). There was no difference in the frequency of BHD and non-BHD patients achieving MCID on at least one threshold score (80.0% vs 84.7%; p-value=0.447) and PASS (67.2% vs 69.3%; p-value=0.778). Functional outcome scores of patients with BHD undergoing arthroscopic treatment for FAIS are not significantly different from patients with normal acetabular coverage at 5-year follow-up. Furthermore, patients with BHD achieve meaningful clinical outcomes at the same rate as non-BHD patients.

Borderline Dysplasia with Acetabular Retroversion: Key Findings in Large Hip Arthroscopy Study Group

Borderline Dysplasia with Acetabular Retroversion: Key Findings in Large Hip Arthroscopy Study Group

Evaluating Stability in Borderline Hip Dysplasia using The Femoro-Epiphyseal Acetabular Roof Index

Evaluating Stability in Borderline Hip Dysplasia using The Femoro-Epiphyseal Acetabular Roof Index

Across the Spectrum from Borderline Dysplasia to Global Pincer Impingement: Arthroscopic Outcomes

Across the Spectrum from Borderline Dysplasia to Global Pincer Impingement: Arthroscopic Outcomes

Decision-making in the Borderline Hip.

Borderline acetabular dysplasia represents a "transitional acetabular coverage" pattern between more classic acetabular dysplasia and normal acetabular coverage. Borderline dysplasia is typically defined as a lateral center-edge angle of 20 to 25 degrees. This definition of borderline dysplasia identifies a relatively narrow range of lateral acetabular coverage patterns, but anterior and posterior coverage patterns are highly variable and require careful assessment radiographically, in addition to other patient factors. Treatment decisions between isolated hip arthroscopy (addressing labral pathology, femoroacetabular impingement bony morphology, and capsular laxity) and periacetabular osteotomy (improving osseous joint stability; often combined with hip arthroscopy) remain challenging because the fundamental mechanical diagnosis (instability vs. femoroacetabular impingement) can be difficult to determine clinically. Treatment with either isolated hip arthroscopy or periacetabular osteotomy (with or without arthroscopy) appears to result in improvements in patient-reported outcomes in many patients, but with up to 40% with suboptimal outcomes. A patient-specific approach to decision-making that includes a comprehensive patient and imaging evaluation is likely required to achieve optimal outcomes.

Adolescent hip dysplasia: what are the symptoms and how to diagnose it.

Adolescent and young adult hip dysplasia is a cause of hip pain which can lead to early hip osteoarthritis. This may result in early hip osteoarthrosis and possible total hip arthroplasty if dysplasia is not recognized and treated. Hip dysplasia in this population can be difficult to diagnose. It is important for primary care providers and pediatricians to recognize the symptoms, physical examination findings, and radiographic findings associated with adolescent hip dysplasia so that the patient can be referred to an orthopedist specializing in hip disorder. The current review includes the most up-to-date literature on the diagnosis of adolescent hip dysplasia. Recent studies have shown that most patients presenting with symptomatic hip dysplasia present with insidious onset hip pain localized to either the groin or lateral aspect of the hip in a C-shape distribution around the inguinal crease. Patients most commonly see several different providers and have pain for a long period prior to accurate diagnosis. There are myriad radiographic measurements of hip dysplasia, many of which are described below that are helpful in initial diagnosis. Adolescent and young adult hip dysplasia can be a cause of early, progressive hip osteoarthritis. Hip dysplasia is a term that represents a spectrum of disorder due to abnormal formation of the hip joint, resulting in an acetabulum that does not sufficiently cover the femoral head. The ability to recognize symptoms, physical examination findings, and radiographic evidence of adolescent hip dysplasia is critical so that the patient can be referred to the appropriate provider and receive timely treatment prior to the onset of degenerative hip disease. This article will focus mainly on the diagnosis of adolescent hip dysplasia. The standard for treatment of acetabular dysplasia in skeletally mature patients is the periacetabular osteotomy; however, nonoperative management and occasionally arthroscopic surgery can also be considered in cases of symptomatic borderline dysplasia.

No Correlation Between Depth of Acetabuloplasty or Postoperative Lateral Center-Edge Angle on Midterm Outcomes of Hip Arthroscopy With Acetabuloplasty and Labral Repair

Background: The treatment of pincer deformity in hip arthroscopy remains controversial, with some authors advocating that over resection may risk early joint deterioration. The role of acetabular resection depth and postoperative acetabular morphology on postoperative outcomes has yet to be defined. Purpose/Hypothesis: This study measures the influence of acetabular resection depth and postoperative lateral center-edge angle (LCEA) on minimum 5-year patient-reported outcomes (PROs), revision rates, and conversion to total hip arthroplasty using a single surgeon’s prospective database. We hypothesized that patients with acetabular resections >10°, as measured by LCEA, or patients with postoperative LCEA outside the normal range of 25° to 35° would have lower PROs, higher revision rates, and higher conversion to total hip arthroplasty at midterm follow-up. Study Design: Cohort study; Level of evidence, 2. Methods: A total of 192 patients who underwent primary hip arthroscopy with acetabuloplasty and labral repair by a single surgeon with a minimum 5-year follow-up met the inclusion criteria. Preoperative and postoperative LCEAs were measured on supine anteroposterior radiographs, and patients were divided into cohorts based on LCEA and acetabular resection depth. Cohorts for postoperative LCEA were <20° (dysplasia), 20° to 25° (borderline dysplasia), 25° to 35° (normal), and >35° (borderline overcoverage). Cohorts for acetabular resection depth were <5°, 5° to 10°, and >10° difference from preoperative to postoperative LCEA. Outcome measures included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), 12-Item Short Form Health Survey, modified Harris Hip Score, Hip Outcome Score, satisfaction scores, revision rates, and conversion to arthroplasty rates. Results: Patients significantly improved in all outcome score measures at final follow-up. There were no statistically significant differences in PRO scores or conversion to total hip arthroplasty between any cohorts in the postoperative LCEA group. There were more revisions in the 25° to 35° cohort than the other cohorts (P = .02). The 5-10° resection depth cohort demonstrated a higher postoperative WOMAC score (P = .03), but otherwise no statistically significant differences were seen between resection depth cohorts in the remaining postoperative outcomes scores, revision rates, or conversion to total hip arthroplasty rates. Conclusion: Patients with postoperative LCEA values outside the normal reference range and with large resections perform similar to those with normal postoperative LCEA values and smaller resections at a minimum 5-year follow-up.

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.

Use of a 3D Virtually Reconstructed Patient-Specific Model to Examine the Effect of Acetabular Labral Interference on Hip Range of Motion.

Background:The labrum is likely to influence impingement, which may also depend on acetabular coverage. Simulating impingement using 3-dimensional (3D) computed tomography (CT) is a potential solution to evaluating range of motion (ROM); however, it is based on bony structures rather than on soft tissue.Purpose:To examine ROM when the labrum is considered in a 3D dynamic simulation. A particular focus was evaluation of maximum flexion and internal rotation angles before occurrence of impingement, comparing them in cases of cam-type femoroacetabular impingement (FAI) and borderline developmental dysplasia of the hip (BDDH).Study Design:Descriptive laboratory study.Methods:Magnetic resonance imaging (MRI) and CT scans of 40 hips (20 with cam-type FAI and 20 with BDDH) were reviewed retrospectively. The thickness and width of the labrum were measured on MRI scans. A virtual labrum was reconstructed based on patient-specific sizes measured on MRI scans. The impingement point was identified using 3D dynamic simulation and was compared with the internal rotation angle before and after labral reconstruction.Results:The thickness and width of the labrum were significantly larger in BDDH than in FAI (P < .001). In FAI, the maximum internal rotation angles without the labrum were 30.3° at 90° of flexion and 56.9° at 45° of flexion, with these values decreasing to 18.7° and 41.4°, respectively, after labral reconstruction (P < .001). In BDDH, the maximum internal rotation angles were 48.0° at 90° of flexion and 76.7° at 45° of flexion without the labrum, decreasing to 31.1° and 55.3°, respectively, after labral reconstruction (P < .001). The differences in the angles before and after labral reconstruction were larger in BDDH than in FAI (90° of flexion, P = .03; 45° of flexion, P = .01).Conclusion:As the labrum was significantly more hypertrophic in BDDH than in FAI, the virtual labral model revealed that the labrum’s interference with the maximum internal rotation angle was also significantly larger in BDDH.Clinical Relevance:The labrum has a significant effect on impingement; this is more significant for BDDH than for FAI.

Arthroscopic management with labral preservation, femoral osteoplasty, and capsular plication in patients with borderline hip dysplasia. Results of a matched-cohort study at minimum twoyear follow-up.

The purpose of this study was to assess intra-operative findings, surgical procedures, and outcomes in a cohort of patients with borderline hip dysplasia treated with arthroscopic labral repair, femoral osteoplasty, and capsular plication, and compare these outcomes with those of a rigorously matched control group without dysplasia. Data were prospectively collected and retrospectively reviewed for patients with a lateral center-edge angle between 20 and 24° who underwent hip arthroscopy surgery between 2014 and 2018. Labral, chondral status, psoas impingement, ligamentum teres, and cam morphology were evaluated. Patient-reported outcomes (PROs) scores included modified Harris Hip Score (mHHS), Hip Outcome Score Activities of Daily Living Subscale (HOS-AVD) and Hip Outcome Score Sport-Specific Subscale (HOS-SSS), and International Hip Outcome Tool-12 (IHOT-12). Clinical relevance was measured with the minimal clinical important difference (MCID), patient acceptable symptom state (PASS), and substantial clinical benefit (SCB). Twenty patients met the inclusion criteria. An age- and sex-matched control group of 40 patients was also selected. Arthroscopic intra-operative findings were similar between cohorts. At a mean follow-up of 50months in the borderline hip dysplasia cohort, and 52months in the control cohort, there was a significant improvement in PROs in both cohorts, and no significant differences could be detected at the latest follow-up. The difference in frequency of patients achieving the MCID, PASS, and SCB was not statistically significant between cohorts. With strict patient selection criteria, hip arthroscopy may be a beneficial approach in patients with borderline hip dysplasia.

Arthroscopic Management of Subspinous Impingement in Borderline Hip Dysplasia and Outcomes Compared With a Matched Cohort With Nondysplastic Femoroacetabular Impingement

Background: Arthroscopic management of femoroacetabular impingement (FAI) in the setting of borderline hip dysplasia is controversial. Recently, there has been increased awareness of a prominent anterior inferior iliac spine (AIIS) resulting in subspinous impingement. Purpose/Hypothesis: The purpose was to report outcomes of arthroscopic subspinous decompression in patients with symptomatic hip impingement and borderline hip dysplasia compared with a matched cohort with nondysplastic FAI. Addressing a prominent subspinous region and cam/pincer lesion in the borderline dysplastic hip may lead to favorable outcomes comparable with those of patients undergoing arthroscopic management of nondysplastic FAI. Study Design: Cohort study; Level of evidence, 3. Methods: Patients with symptomatic hip impingement, borderline dysplasia (lateral center-edge angle [LCEA], 18°-24°), and prominent AIIS (BDSI group) whose nonoperative management failed and who subsequently underwent arthroscopic subspinous decompression were retrospectively identified. Three-dimensional computed tomography imaging was used to categorize AIIS morphology into type 1, 2, or 3 (Hetsroni classification). Patient-reported outcome (PRO) scores consisting of the modified Harris Hip Score (mHHS), Hip Outcome Score–Activities of Daily Living (HOS-ADL), and Hip Outcome Score–Sport-Specific Subscale (HOS-SSS) were obtained preoperatively and at an average of 44 months postoperatively (range, 23-61 months). Exclusion criteria were Tönnis osteoarthritis grade >1 and a history of previous hip procedures. An age-, sex-, and body mass index–matched cohort of patients without dysplasia (LCEA, >25°) who underwent arthroscopic FAI surgery with a minimum 2-year follow-up were selected to serve as the control group. Results: Eighteen patients, 19 hips (14 women and 4 men; average age, 28 years) were included. Of the 19 hips in the BDSI group, the average LCEA and alpha angle were 21.8° and 66.2°, respectively; 14 hips were Hestroni type 2, and 5 hips were type 1. There were no postoperative complications or additional procedures performed since the last follow-up. Repeated-measures analysis of variance revealed a significant improvement in all PRO scores from preoperatively to the last follow-up: mHHS, 64.7 to 87.7 (P < .001); HOS-ADL, 62.1 to 92.1 (P < .001); HOS-SSS, 26.5 to 87.1 (P < .001). An analysis of covariance revealed that patients with type 2 AIIS had a significantly higher postoperative mHHS than those with a type 1 morphology (88.3 and 95.6, respectively; P < .01) The BDSI group had a significantly lower preoperative HOS-SSS (26.5; P < .001) in comparison with the control group. However, there was no significant difference in postoperative outcome scores between groups. The BDSI group underwent significantly more microfracture, capsular plication, and ligamentum teres debridement (15.8%; P = .04). Conclusion: Arthroscopic AIIS decompression in patients with coexisting borderline dysplasia and subspinous impingement is a safe and effective method of treatment that produces outcomes comparable with those of a cohort with nondysplastic FAI.

Is hip arthroscopy useful in the treatment of borderline dysplasia?: a case-control study

IntroductionSince arthroscopy remains a controversial treatment of hip dysplasia, our objective was to analyse its clinical and radiological results in a cohort of patients with dysplasia and compare them to controls with femoroacetabular impingement (FAI). Material and methodsWe retrospectively analysed a series of patients who underwent hip arthroscopy for the treatment of labral pathology; 29 of them with borderline hip dysplasia and 197 with FAI, comparing reoperations and joint survival. The diagnosis of borderline dysplasia was made with a lateral centre-edge angle greater than 18° but less than 25°. The average follow-up was 43 months. We performed a multivariate regression analysis to evaluate the association of reoperations with different demographic, radiological and intraoperative variables. ResultsSeven complications were registered in the FAI group (1 medically treated superficial wound infection, 3 pudendal nerve paraesthesias, 1 deep vein thrombosis and 2 heterotopic ossifications) and none in the dysplasia group. While 5 patients from the FAI group required a new surgery, none of the dysplasia group was re-operated (p=.38). After adjusting for confounders, reoperation showed a very strong association with the finding of osteochondral lesions during index surgery, with a coefficient of .12 (p<.001, 95%CI=.06-.17). ConclusionHip arthroscopy was useful in the treatment of borderline dysplasia, without non-inferior survival compared to the FAI group. We suggest indicating it carefully in dysplasia cases, whenever the symptoms of femoroacetabular friction prevail over those of instability.

¿Es útil la artroscopia de cadera para el tratamiento de la displasia limítrofe?: análisis de casos y controles

IntroductionSince arthroscopy remains a controversial treatment of hip dysplasia, our objective was to analyse its clinical and radiological results in a cohort of patients with dysplasia and compare them to controls with femoroacetabular impingement (FAI). Material and methodsWe retrospectively analysed a series of patients who underwent hip arthroscopy for the treatment of labral pathology; 29 of them with borderline hip dysplasia and 197 with FAI, comparing reoperations and joint survival. The diagnosis of borderline dysplasia was made with a lateral centre-edge angle greater than 18° but less than 25°. The average follow-up was 43 months. We performed a multivariate regression analysis to evaluate the association of reoperations with different demographic, radiological and intraoperative variables. ResultsSeven complications were registered in the FAI group (1 medically treated superficial wound infection, 3 pudendal nerve paraesthesias, 1 deep vein thrombosis and 2 heterotopic ossifications) and none in the dysplasia group. While 5 patients from the FAI group required a new surgery, none of the dysplasia group was re-operated (p=.38). After adjusting for confounders, reoperation showed a very strong association with the finding of osteochondral lesions during index surgery, with a coefficient of .12 (p<.001, 95%CI=.06-.17). ConclusionHip arthroscopy was useful in the treatment of borderline dysplasia, without non-inferior survival compared to the FAI group. We suggest indicating it carefully in dysplasia cases, whenever the symptoms of femoroacetabular friction prevail over those of instability.