Outcomes After Arthroscopic Treatment of Femoroacetabular Impingement for Patients With Borderline Hip Dysplasia

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

IV Therapeutic Study.

Patients With Dysplasia Achieve Similar Outcomes and Survivorship As Non-Dysplastic Patients 10 Years Following Hip Arthroscopy for Femoroacetabular Impingement

PURPOSE

To determine the long-term outcomes of hip arthroscopy (HA) for femoroacetabular impingement (FAI) in the presence of concomitant lateral rim dysplasia compared to a matched control group.

METHODS

Patients undergoing HA between January 2009 and October 2013 with minimum 10-year follow up were reviewed. Inclusion criteria consisted of hip arthroscopy patients for FAI with evidence of lateral rim dysplasia (LCEA of <25o). Patients with lateral rim dysplasia, were matched to patients with a LCEA >30o, based on sex, Tonnis grade and age. Outcomes included survival (avoidance of total hip replacement {THR}), repeat-HA and patient-reported outcomes. Survivorship was assessed using a Kaplan-Meier curve and Log ranks test, while revision rates between groups were assessed using Chi Squared analysis. Between and within group analysis for PROs were conducted using Mann Whitney U and Wilcoxon signed ranks respectively. The proportion of cases achieving the patient acceptable symptom state (PASS) was compared between groups using Chi squared analysis.

RESULTS

Forty-six dysplasia and 90 control cases were reported on. There was no statistical difference between groups for baseline metrics apart from the LCEA (p<0.001), Sharp angle (p<0.001) and Tonnis angle (p<0.001). By 10 years, 9% of dysplasia cases and 4% of control cases converted to THR. There was no statistical difference between groups for survival or revision rates. Both groups reported improvements in PROs and there was no difference between PRO scores at either timepoint. Excluding those undergoing THR, 84% and 83% of dysplasia and control cases respectively achieved PASS.

CONCLUSION

Hip arthroscopy for symptomatic femoroacetabular impingement (FAI) is a successful treatment in cases where dysplasia is present. Low complication rates, comparable outcomes to those without lateral rim dysplasia, and a high survivorship rate of 91% at minimum 10-year follow up are observed. Increasing Tonnis angle preoperatively may increase the risk of THR conversion.

LEVEL OF EVIDENCE

IV Retrospective Cohort Study.

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.

Characterizations of Capsule Closure in Hip Arthroscopy Are Infrequently and Incompletely Reported: A Systematic Review

Purpose

To review the recent literature to provide an updated characterization of capsule closure techniques in hip arthroscopy and to determine if the characteristics of closure impacted clinical outcomes.

Methods

In keeping with the Preferred Reporting in Systematic Reviews and Meta Analyses (PRISMA) guidelines, a systematic review was performed with the following eligibility criteria: patients over 18 years of age who underwent primary hip arthroscopy with reporting of patient reported outcome measures or revision/failure, and a sufficiently detailed description of capsule closure. The GRADE framework evaluated study quality, and ROBINS-I evaluated the risk of bias.

Results

Across 18 studies (N = 3277) an interportal capsulotomy was reported in 12 studies (1972/3277) cases, and a T-type capsulotomy was reported in six studies (1305/3277) cases). Six studies reported using #2 suture. Nonabsorbable suture was reported in six studies, and absorbable suture in six studies. The rate of failure was 10.5% across five studies (N = 1133) and the rate of revision was 4.4% across 13 studies (N = 2957).

Conclusions

Capsule closure is commonly performed with #2 high strength suture-the T-type using two to three sutures in the vertical limb and two to three in the transverse limb, and the interportal type using two to three sutures. Compared to earlier reports, there is a trend for increased utilization of T-type capsulotomy. Although there is a growing body of investigations into the efficacy of routine capsule closure following hip arthroscopy, our results demonstrate infrequent and inconsistent reporting of capsule closure characteristics.

Level of Evidence

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

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.

Acetabular Rim Disorders: Epidemiology, Etiology, Management, and Outcomes

» Anatomic disorders of the acetabular rim are a common, correctable source of hip pain in younger patients.» Some common conditions of involving abnormal acetabular rim morphology include developmental dysplasia of the hip, pincer-type femoroacetabular impingement, acetabular protrusion, and acetabular retroversion.» Treatment option for these conditions were historically limited to open osteotomy and osteoplasty procedures; however, there is increasing use of arthroscopic intervention for these patients.» Arthroscopic intervention has demonstrated short-term success in a variety of focal acetabular rim disorders; however, further research is needed to determine the long-term outcomes of these procedures and their utility in more global pathology.

Borderline Dysplastic Hips Undergoing Hip Arthroscopy Achieve Equivalent Patient Reported Outcomes When Compared With Hips With Normal Acetabular Coverage: A Systematic Review and Meta-Analysis

PURPOSE

To systematically review and meta-analyze studies reporting lateral center edge angle as it relates to patient-reported outcome (PRO) measures and clinically notable outcome assessments for patients undergoing hip arthroscopy for femoroacetabular impingement syndrome or labral pathology with borderline dysplastic hips (BDH).

METHODS

PubMed, EMBASE, and the Web of Science Core Collection databases were queried for articles evaluating lateral center edge angle as a predictor of PRO after hip arthroscopy. Articles were eligible for meta-analysis if they compared PROs measures between patients with normal acetabular coverage and borderline dysplasia and were at least level III evidence. Continuous random-effects models with standardized mean differences were used to compare postoperative Hip Outcome Score-Activities of Daily Living and sports subscales, modified Harris Hip Score, international Hip Outcome Tool scores, Satisfaction, and Visual Analog Scale Pain scores between normal coverage and borderline dysplastic groups.

RESULTS

Overall, 989 hips undergoing arthroscopy from six investigations were included in this meta-analysis, including 315 borderline dysplastic subjects (mean age 27.5 years) and 674 subjects with normal coverage (mean age 26.9 years). Borderline dysplastic and normal coverage cohorts were followed for an average of 37.0 and 36.8 months, respectively. Postoperative PRO measures (Hip Outcome Score-Activities of Daily Living, Hip Outcome Score-Sports Subscale, modified Harris Hip Score, international Hip Outcome Tool-12, Satisfaction, and Visual Analog Scale Pain) collected approximately three years after hip arthroscopy were not markedly different between subjects with BDH when compared with patients with normal coverage.

CONCLUSIONS

In a meta-analysis of the available literature, patients with BDH are able to equally reach statistically similar clinical outcomes after isolated hip arthroscopy as compared with control subjects without dysplasia at short-term follow-up. A BDH should not be considered a contraindication to hip arthroscopy when optimal PRO achievement is the goal.

LEVEL OF EVIDENCE

Level III, Systematic Review and Meta-Analysis.

Radiographic Predictors of Reoperation in Adolescents Undergoing Hip Preservation Surgery for Femoroacetabular Impingement

BACKGROUND

Femoroacetabular impingement (FAI) is a condition caused by repetitive abutment of a morphologically abnormal proximal femur and/or acetabulum that may result in chondral and labral pathology. An understanding of radiographic parameters associated with successful primary surgery has not been well established.

PURPOSE

To determine preoperative radiographic parameters that predict reoperation for FAI and correlate radiographic measurements with outcomes in these patients.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

A prospectively collected institutional registry of adolescent patients (age, <19 years) who underwent surgery for FAI (arthroscopic/open) was reviewed. Preoperative standing anteroposterior pelvic radiographs were analyzed for femoroepiphyseal acetabular roof (FEAR) index, as well as lateral center-edge angle (LCEA) and alpha, Tönnis, and Sharp angles. Patient-reported outcomes (PROs) (modified Harris Hip Score, Hip disability and Osteoarthritis Outcome Score) were analyzed preoperatively and at 1- and 2-year followup. Radiographic indication of risk for reoperation was evaluated using receiver operating characteristic (ROC) analysis. Spearman correlation was calculated between radiographic measurements and PROs at 2 years postoperatively.

RESULTS

A total of 81 patients (91 hips) underwent primary surgery (57 surgical dislocations vs 34 arthroscopies) for FAI. The mean age at time of primary operation was 16.23 years (range, 10.4-19.6 years) (73.6% female). Eleven hips (12.1%) underwent reoperation at a mean of 20.6 months from primary surgery. The LCEA, FEAR index, Tönnis angle, and Sharp angle before index surgery were significantly different (P < .05) between patients who underwent reoperation and those who did not. ROC analysis indicated that LCEA <22°, FEAR index >-8.7°, Tönnis angle >6.0°, and Sharp angle >44° were predictors for increased risk of reoperation. Using the cutoff values from the ROC analysis in this series, 43% of patients with an LCEA ≤22° had a repeat procedure, while only 8% of those with an LCEA >22° had a repeat procedure. Similar trends were seen with the other aforementioned acetabular radiographic measurements (FEAR index, Tönnis angle, Sharp angle). Patients who did not require a reoperation demonstrated significant improvement in all PRO categories from their preoperative to 2-year postoperative visits (P < .0001).

CONCLUSION

In patients undergoing treatment for FAI, a reoperation was associated with radiographic signs of hip dysplasia, indicating that patients with a shallower acetabulum are at risk for a repeat operation.

High Survivorship and Comparable Patient-Reported Outcomes at a Minimum 5 Years After Hip Arthroscopic Surgery in Patients With Femoroacetabular Impingement, With and Without Lateral Rim Dysplasia

BACKGROUND

Femoroacetabular impingement (FAI) in patients with dysplasia presents a unique challenge to surgeons. Short-term outcomes are conflicting, while longer term follow-up data are only emerging.

PURPOSE

To quantify midterm (minimum 5-year follow-up) outcomes after the arthroscopic correction of FAI in the presence of lateral rim dysplasia compared with a matched control group with FAI with normal acetabular coverage.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Prospective outcome data, collected in a consecutive series of patients undergoing arthroscopic FAI correction with lateral rim dysplasia (lateral center-edge angle [LCEA] of 13°-25°), were reviewed (N = 75 cases). An age- and sex-matched control group of 120 cases was also formed (LCEA >25°). Survivorship was defined as the avoidance of total hip replacement and assessed using a Kaplan-Meier curve with the log-rank test. Survival rates and patient-reported outcome measure (PROM) scores (modified Harris Hip Score [mHHS], University of California, Los Angeles [UCLA], 36-Item Short Form Health Survey [SF-36], and Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC] preoperatively and at 5 years postoperatively) were compared between the groups. The proportion of patients across groups achieving the minimal clinically important difference (MCID) was compared for each PROM. The dysplasia group was also analyzed independently to identify any factors that may indicate a less favorable outcome using regression analysis. The group was divided into 2 subgroups: borderline dysplasia (LCEA of 20°-25°) and severe dysplasia (LCEA <20°).

RESULTS

The survival rate in the dysplasia group was 97%. There was no statistical difference with respect to survival rates or any PROM scores (P > .05 for all) between the groups. There were similar rates of achieving the MCID between the groups for the mHHS, UCLA, and WOMAC. The FAI control group had a higher rate of achieving the MCID for the SF-36 (P = .012; effect size = 0.274 [small]). Subgroup analysis indicated a lower survival rate (78% vs 100%, respectively; P < .001) in female cases in the dysplasia group (n = 9) compared with male cases in the dysplasia group (n = 66). The UCLA score in female cases in the dysplasia group at 5 years was statistically lower compared with that in male cases in the dysplasia group (6 vs 10, respectively; P = .003; effect size = 0.378 [medium]), but no other outcome revealed any differences between the sexes. There were also no variables identified on regression analysis that accurately predicted a poorer outcome in the dysplasia group. When stratified by severity, there was no difference in survivorship or outcomes between those with severe dysplasia (LCEA <20°; n = 11) and those with borderline dysplasia (LCEA of 20°-25°; n = 64).

CONCLUSION

An arthroscopic intervention was a successful treatment option for FAI in the presence of lateral rim dysplasia at midterm follow-up. Irrespective of the severity of dysplasia, patients can expect similar improvements to those in patients with normal femoral head coverage.

Return to sport after arthroscopic surgery for femoroacetabular impingement

BACKGROUND

Femoroacetabular impingement (FAI) is common among the active and young population. The present study analysed the rate of return to sport, related influencing factors, and the sport activity level according to the Hip Outcome Score - Sport-Specific Subscale (HOS-SSS).

METHODS

The literature search was performed in December 2020. All clinical trials investigating HOS-SSS and/or return to sport after arthroscopic treatment for FAI were considered for inclusion. The outcomes of interest were to analyse the rate of return to sport and the sport activity level according to the HOS-SSS in patients who underwent arthroscopic osteoplasty for FAI.

RESULTS

Data from 41 studies (4063 procedures) were retrieved. A total of 88.75% (581 of 655) of patients returned to sports within a mean of 37.4 ± 16.5 months. The HOS-SSS score improved from 45.0 ± 10.6 to 73.1 ± 9.5 (P < 0.0001) at last follow-up. The following baseline characteristics evidenced positive association with post-operative activity level: lighter weight (P = 0.01), younger age (P = 0.001), Tönnis angle grade I (P = 0.009), greater HHS (P = 0.01), NAHS (P < 0.0001) and HOS-ADL (P = 0.01).

CONCLUSION

Arthroscopic treatment for FAI resulted in excellent results in terms of return to sport. Moreover, lighter weight and younger age, greater HHS, NAHS, HOS-ADL at baseline were positively associated with post-operative sport activity level.

LEVEL OF EVIDENCE

IV, systematic review.

Outcomes of Periacetabular Osteotomy for Borderline Acetabular Dysplasia

BACKGROUND

The optimal surgical treatment (hip arthroscopy compared with periacetabular osteotomy [PAO]) for borderline acetabular dysplasia (lateral center-edge angle [LCEA], 18° to 25°) remains a topic of debate. To date, the literature has focused primarily on arthroscopy outcomes, with only a few small reports on PAO outcomes. The purpose of this study was to define PAO outcomes in a large cohort of borderline hips. In a secondary analysis, we assessed the effect of prior failed arthroscopy, concurrent hip arthroscopy, and concurrent femoral osteoplasty on PAO outcomes in this cohort.

METHODS

A prospective database was retrospectively reviewed for patients who underwent PAO for symptomatic instability in the setting of borderline dysplasia (LCEA, 18° to 25°). Of the 232 identified hips, 186 (80.2%) were assessed at a mean follow-up of 3.3 ± 2.0 years postoperatively. The mean patient age was 25.2 ± 8.5 years (range, 14 to 45 years), and 88.2% were female. Thirty hips (16.1%) had undergone a failed prior arthroscopy. Arthroscopy was performed concurrently with the PAO in 130 hips (69.9%), and femoral osteoplasty was performed concurrently in 120 hips (64.5%). The modified Harris hip score (mHHS) was assessed relative to the minimal clinically important difference (MCID) of 8 and patient acceptable symptom state (PASS) of 74. Clinical failure was defined as a reoperation for persistent symptoms or a failure to achieve either the mHHS MCID or PASS.

RESULTS

Of the 156 hips undergoing a primary surgical procedure, clinical success was achieved in 148 hips (94.9% [95% confidence interval (CI), 90.2% to 97.4%]). Two hips (1.3% [95% CI, 0.4% to 4.6%]) underwent reoperation (hip arthroscopy) for persistent symptoms and an additional 6 hips (3.8% [95% CI, 1.8% to 8.1%]) failed to achieve the mHHS MCID or PASS, for a clinical failure rate of 5.1% (95% CI, 2.6% to 9.8%); 8.8% reported dissatisfaction with the surgical procedure. Clinical failure was more frequent among the 30 hips (23.3% [95% CI, 11.8% to 40.9%]; p = 0.001) that had undergone a prior failed arthroscopy. There were no outcome differences between hips that had or had not undergone concurrent hip arthroscopy or femoral osteoplasty.

CONCLUSIONS

This study demonstrates excellent early outcomes of PAO for borderline acetabular dysplasia, with significant clinical improvement in 94.9% of patients undergoing a primary surgical procedure; 91.2% were satisfied with the surgical procedure.

LEVEL OF EVIDENCE

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

The posterior capsule is distended in dysplastic hips, but the anterior capsule is not

PURPOSE

In the setting of acetabular dysplasia, the increased translational motion of the femur may damage the labrum and cartilage, as well as stretch the capsule. The purpose of the study was to investigate the relationship between the acetabular coverage and the capsular stiffness by assessing the distension of anterior and posterior joint recesses on the hip computed tomography arthrography.

METHODS

One hundred thirty-three patients (138 hips) with a median age of 36 years (range 18-50 years) who received the computed tomography arthrography for evaluation of nonarthritic hip pain in our institute between 2015 and 2017 were retrospectively reviewed. The maximal distance between the anterior/posterior capsule and the anterior femoral head-neck junction/posterior femoral head on the axial imaging of computed tomography arthrography was defined as the width of anterior/posterior joint recess. The width of anterior/posterior joint recess was adjusted with the diameter of the femoral head and was then compared between acetabular dysplasia (lateral center-edge angle < 25°), normal acetabulum (lateral center-edge angle between 25 and 39°), and deep acetabulum (lateral center-edge angle > 39°). In addition, the standard univariate linear regression analysis was used to investigate the relationship between the adjusted width of anterior/posterior joint recess and anterior/posterior coverage of the hip, determined by the anterior/posterior wall index.

RESULTS

The adjusted width of posterior joint recess was significantly greater in the acetabular dysplasia group than the normal acetabulum and deep acetabulum groups (p < 0.01 and p = 0.02, respectively). There was no significant difference of the adjusted width of anterior joint recess between the groups (n.s.). The adjusted width of posterior joint recess had a significant but weak negative correlation with the anterior wall index (r =  - 0.25, p < 0.001), and no correlation with the posterior wall index (r =  - 0.0004, n.s.). There was no significant correlation between the adjusted width of anterior joint recess and the anterior/posterior wall index (r = 0.05, n.s./r = 0.07, n.s.).

CONCLUSIONS

The distension of posterior capsule on the computed tomography arthrography was significantly greater in acetabular dysplasia. In addition, there was a significant but weak negative correlation between the distension of posterior capsule and the anterior coverage of the hip. It indicated a looser posterior capsule was observed in a dysplastic hip. The relevance of posterior capsular laxity to clinical outcomes warrants further investigation. Given the fact that the distension of anterior capsule was not significantly higher in acetabular dysplasia, the need of anterior capsular plication in a dysplastic hip should be carefully evaluated.

LEVEL OF EVIDENCE

Level III.

Hip Arthroscopy With Bone Marrow Aspirate Injection for Patients With Symptomatic Labral Tears and Early Degenerative Changes Shows Similar Improvement Compared With Patients Undergoing Hip Arthroscopy With Symptomatic Labral Tears Without Arthritis

PURPOSE

To define the clinical effect of intra-articular injection of iliac crest-derived bone marrow aspirate concentrate (BMAC) at the time of hip arthroscopy in patients with symptomatic labral tears and early radiographic degenerative changes.

METHODS

A retrospective review of a prospectively collected hip registry database was performed. Patients with symptomatic labral tears and Tönnis grade 1 or 2 degenerative changes who underwent labrum-preserving hip arthroscopy with BMAC injection were included and were matched with patients who underwent hip arthroscopy without BMAC injection. Patient-reported outcomes (PROs) collected preoperatively and up to 2 years postoperatively included the modified Harris Hip Score, Hip Outcome Score-Activities of Daily Living, Hip Outcome Score-Sport, and International Hip Outcome Tool 33 score. Clinical relevance was measured with the minimal clinically important difference, patient acceptable symptom state, and substantial clinical benefit for each outcome score.

RESULTS

A total of 35 patients underwent labrum-preserving hip arthroscopy with BMAC injection and were matched with 35 control patients. There were no differences in demographic characteristics between the groups (P > .05). The BMAC group consisted of 22 patients (62.9%) with Tönnis grade 1 changes and 13 (37.1%) with Tönnis grade 2 changes, whereas all 35 control patients had Tönnis grade 0 hips. All PROs were significantly improved in both groups at 2 years, with no difference in improvement. The rate of failure requiring conversion to total hip arthroplasty was 14.3% (mean, 1.6 years postoperatively) in the BMAC group and 5.7% (mean, 7 years postoperatively) in the control group (P = .09). The difference in the frequency of patients achieving the minimal clinically important difference, patient acceptable symptom state, and substantial clinical benefit was not statistically significant between cohorts.

CONCLUSIONS

In a challenging group of patients with symptomatic labral tears and early radiographic degenerative changes, hip arthroscopy with BMAC injection results in statistically and clinically significant improvement in PROs comparable to a group of patients with nonarthritic hips undergoing hip arthroscopy at short-term follow-up.

LEVEL OF EVIDENCE

Level III, retrospective comparative therapeutic trial.

Use of Anatomic Radiographic Horizons for the Lateral Center-Edge Angle in the Classification of Hip Dysplasia

BACKGROUND

The lateral center-edge angle of Wiberg (LCEA) and Tönnis angle (TA) rely on a "horizon" that functions as a reference point for measurements of hip dysplasia on weightbearing anteroposterior pelvis radiographs. There are 3 different horizons that are currently utilized depending on surgeon preference: (1) a line parallel to the radiographic floor (F), (2) a line that connects the inferior portions of the acetabular teardrops (ATs), or (3) a line that connects the ischial tuberosities (ITs). It is imperative to accurately assess the degree of hip dysplasia on initial workup to select the appropriate surgical intervention.

PURPOSE

To assess how the choice of a radiographic horizon affects the measurements of the LCEA and TA. The secondary purpose was to assess how the horizon affected the classification of hips as either normal, borderline dysplastic, or dysplastic.

STUDY DESIGN

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

METHODS

The LCEA and TA were measured on all preoperative weightbearing anteroposterior pelvis radiographs for 186 consecutive patients who underwent hip preservation surgery between February 2016 and November 2020 (140 hip arthroscopic procedures, 46 combined hip arthroscopic procedures with periacetabular osteotomy), 3 times per hip, each time using an F, AT, and IT horizon. The Student t test was used to analyze the differences in the measurements of the LCEA and TA, and discordance rates in the dysplasia classification between horizons were quantified.

RESULTS

For the entire study population, the mean LCEA_F (23.4°± 7.4°) was significantly greater than the mean LCEA_IT (23.1°± 7.2°) (95% CI, -0.634 to -0.003; P = .047) and mean LCEA_AT (23.0°± 7.1°) (95% CI, -0.723 to -0.139; P = .004). There was no difference between the LCEA_IT and LCEA_AT (95% CI, -0.305 to 0.080; P = .251). When stratified by hip arthroscopic surgery, the mean LCEA_F (26.3°± 5.6°) was significantly greater than the mean LCEA_AT (25.8°± 5.3°) (95% CI, -0.845 to -0.162; P = .004). Overall, there was a 17.7% and 18.3% discordance rate in the dysplasia classification using the LCEA_IT and LCEA_AT compared with the LCEA_F, respectively. There were no statistically significant differences between the mean TA_IT, TA_AT, and TA_F for the entire study population, the arthroscopic surgery group, and the combined arthroscopic surgery and periacetabular osteotomy group.

CONCLUSION

There was no statistical difference between the AT and IT horizons for LCEA measurements. The dysplasia classification was in better agreement between the 2 anatomic horizons compared with the F horizon. The TA was not affected by changes in the horizon.

External Validation of the FEAR Index in Borderline Acetabular Dysplasia

Background

Given the lack of established, externally validated criteria for the diagnosis of unstable hips, the Femoro-Epiphyseal Acetabular Roof (FEAR) index has been proposed as a useful tool for identifying hips with instability in the setting of borderline acetabular dysplasia.

Purposes

To (1) determine the external performance of the FEAR index in identifying hips with a clinical diagnosis of instability in the setting of borderline dysplasia and (2) assess the performance of the FEAR index compared with acetabular inclination or physeal scar angle alone.

Study Design

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

Methods

The authors reviewed 176 patients with borderline acetabular dysplasia (lateral center-edge angle, 20°-25°). A positive FEAR index was defined as ≥5°. An alternative threshold ≥2° was also assessed. Significant instability was determined by the senior surgeon based on the combination of patient and radiographic features; unstable hips were treated with periacetabular osteotomy (with or without hip arthroscopy), and stable hips were treated with isolated hip arthroscopy.

Results

Only 18% of borderline hips had a positive FEAR index. The ≥5° positive FEAR index threshold had a sensitivity of 33% (23/70) and specificity of 92% (98/106) in predicting the clinical diagnosis of instability. The ≥2° FEAR index threshold had a sensitivity of 39% (27/70) and specificity of 89% (94/106) in predicting the clinical diagnosis of instability. No alternative threshold for the FEAR index resulted in high levels of sensitivity and specificity. A threshold of -5° was required to reach an adequate sensitivity of 74%. The FEAR index remained a significant predictor of hip instability even after controlling for acetabular inclination (odds ratio, 1.12; P < .001) or physeal scar angle (odds ratio, 1.6; P < .001).

Conclusion

In the current study, a positive FEAR index was generally indicative of the presence of clinical instability, but the FEAR index alone remained inadequate to fully define the instability of a given hip, as it demonstrated low sensitivity (only 33%) in the external validation. The FEAR index is best used in the context of other clinical and radiographic features.

Outcomes for the Arthroscopic Treatment of Femoroacetabular Impingement Syndrome With Acetabular Retroversion: A 3D Computed Tomography Analysis

BACKGROUND

Increased attention has been directed toward the acetabular morphology in the management of patients with femoroacetabular impingement syndrome (FAIS). Whether acetabular version influences patient-reported outcomes remains poorly understood.

PURPOSE

To use computed tomography (CT)-based 3-dimensional (3D) bone models to (1) quantify acetabular version in patients with FAIS, (2) compare acetabular version on 3D bone models with current plain radiographic parameters, and (3) explore the relationship between the magnitude of acetabular version and minimum 2-year clinical outcomes after hip arthroscopy.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Three-dimensional models of the pelvis and femur were generated by semiautomated segmentation and aligned to a standard coordinate system. Acetabular version was quantified at the 3-o'clock position, and 3 groups were identified: acetabular retroversion (AR; <15°), normal acetabular version (NV; 15°-25°), and acetabular anteversion (AA; >25°). Patient demographic characteristics, plain radiographic parameters, and clinical outcomes were analyzed, including the Hip Outcome Score-Activities of Daily Living, Hip Outcome Score-Sports Subscale, modified Harris Hip Score (mHHS), International Hip Outcome Tool (iHOT-12), and visual analog scale (VAS) for pain and satisfaction.

RESULTS

Preoperative CT scans were acquired in 105 consecutive patients before hip arthroscopy for FAIS, of which 84 (80.0%) completed minimum 2-year patient-reported outcomes. The mean ± SD age and body mass index of patients were 33.9 ± 12.6 years and 26.0 ± 5.4, respectively; 70.2% were female. The number of patients and the mean central acetabular version within each group were as follows: AR (n = 12; 11.3°± 2.7°), NV (n = 56; 20.7°± 2.9°), and AA (n = 16; 28.5°± 2.7°). Posterior wall sign was the only plain radiographic parameter that was significantly more observed in the AR group than in the other 2 groups. At minimum 2-year follow-up, significant between-group differences in the mHHS, iHOT-12, and VAS for pain and satisfaction (P < .05) were appreciated, while post hoc analysis with Bonferroni correction (P < .0167) found lower scores on the mHHS, iHOT-12, and VAS for pain and satisfaction in patients with AR as compared with NV. Lower scores on the VAS for satisfaction were reported in patients with AR when compared with AA (P = .006) but not on the mHHS (P = .023), iHOT-12 (P = .032), or VAS for pain (P = .072).

CONCLUSION

Traditional plain radiographic indices to describe AR, including crossover sign and ischial spine sign, were not reliable in defining AR according to 3D models derived from CT scans. Only the posterior wall sign was observed in a higher proportion in the AR group. Patients with AR demonstrated inferior outcomes when compared with patients with NV and AA after hip arthroscopy for FAIS.

FEAR index in predicting treatment among patients with femoroacetabular impingement and hip dysplasia and the relationship of femoral version

The Femoro-Epiphyseal Acetabular Roof (FEAR) index is a newer measurement to identify the hip instability with borderline acetabular dysplasia. The purpose of this study is to (i) validate the FEAR index in determining the stability of the hip in patients who have previously been treated surgically for femoroacetabular impingement (FAI) and/or developmental dysplasia of the hip (DDH) and (ii) to examine the relationship between the FEAR index and femoral version, lateral center edge angle, Tönnis angle and alpha angle (AA). Patient demographics and radiographic measurements of 215 hips (178 patients), 116 hips treated with hip arthroscopy for FAI and 99 hips treated with periacetabular osteotomy (PAO) for DDH were compared between groups. The sensitivity and specificity of the FEAR index to detect the surgical procedure performed (PAO or hip arthroscopy) was calculated, and a threshold value was proposed. Pearson's correlation coefficients were used to describe the relationships between the FEAR index, femoral version and other radiographic measurements. The FEAR index was higher in patients with DDH versus FAI (DDH: 2.81 ± 0.50° versus FAI: -1.00 ± 0.21°, P < 0.001). A FEAR index threshold value of 3° had a sensitivity and specificity of 80% and 81%, respectively, for correctly predicting the surgical procedure performed. Femoral version was positively associated with the FEAR index in the setting of DDH (r = 0.36, P = 0.001) but not FAI (r = 0.02, P = 0.807). A FEAR index of 3° predicted treatment with 80% sensitivity and 81% specificity. In addition, femoral version significantly correlates with the FEAR index in the setting of DDH but not FAI.

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

Purpose of Review

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

Recent Findings

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

Summary

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

Routine Capsular Closure With Hip Arthroscopic Surgery Results in Superior Outcomes: A Systematic Review and Meta-analysis

BACKGROUND

In hip arthroscopic surgery, capsulotomy is performed to improve visualization and allow instrumentation of the joint. Traditionally, the defect has been left unrepaired; however, increasing evidence suggests that this may contribute to persistent pain and iatrogenic capsular instability. Nevertheless, the clinical benefit of performing routine capsular repair remains controversial.

PURPOSE/HYPOTHESIS

We conducted a systematic review and meta-analysis to investigate the effects of routine capsular closure on patient-reported outcomes (PROs), hypothesizing that superior PROs would be observed with routine capsular closure.

STUDY DESIGN

Meta-analysis and systematic review; Level of evidence, 4.

METHODS

A systematic review and meta-analysis was conducted according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The terms "hip,""arthroscopy,""capsule,""capsular,""repair," and "closure" were used to query Ovid MEDLINE, Embase, CENTRAL (Cochrane Central Register of Controlled Trials), CINAHL (Cumulative Index to Nursing and Allied Health Literature), SPORTDiscus, and PubMed. Articles with PROs stratified by capsular management were included. Multivariate mixed-effects metaregression models were implemented with study-level random-effects and fixed-effects moderators for capsular closure versus no repair and after controlling for surgical indication and preoperative PROs. The effect of repair on both the postoperative score and the change in scores was evaluated via the Harris Hip Score (HHS)/modified HHS (mHHS), Hip Outcome Score (HOS)-Activities of Daily Living (ADL), and HOS-Sport Specific Subscale (SSS), with a supplemental analysis of additional outcomes.

RESULTS

Of 432 initial articles, 36 were eligible for analysis, with results for 5132 hip arthroscopic procedures. The capsule was repaired in 3427 arthroscopic procedures and unrepaired in 1705. Capsular repair was associated with significantly higher postoperative HHS/mHHS (2.011; SE, 0.743 [95% CI, 0.554-3.467]; P = .007), HOS-ADL (3.635; SE, 0.873 [95% CI, 1.923-5.346]; P < .001), and HOS-SSS (4.137; SE, 1.205 [95% CI, 1.775-6.499]; P < .001) scores as well as significantly superior improvement on the HHS/mHHS (2.571; SE, 0.878 [95% CI, 0.849-4.292]; P = .003), HOS-ADL (3.315; SE, 1.131 [95% CI, 1.099-5.531]; P = .003), and HOS-SSS (3.605; SE, 1.689 [95% CI, 0.295-6.915]; P = .033).

CONCLUSION

This meta-analysis is the largest to date evaluating the effect of capsular closure on PROs and demonstrates significantly higher mean postoperative scores and significantly superior improvement with repair, while controlling for the effects of preoperative score and surgical indication. The true magnitude of the benefit of capsular repair may be clarified by large prospective randomized studies using PRO measures specifically targeted and validated for hip arthroscopic surgery/preservation.

Hip Range of Motion Is Increased After Hip Arthroscopy for Femoroacetabular Impingement: A Systematic Review

Purpose

To investigate the impact of arthroscopic correction of symptomatic femoroacetabular impingement on postoperative hip range of motion (ROM), as an objectively measured postoperative clinically reported outcome.

Methods

A systematic review of the current literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, OVID/MEDLINE, EMBASE, and Cochrane databases were queried in November 2020. Studies not reporting pre- to postoperative ROM measurements were excluded. Methodologic quality was assessed using the MINORS assessment, and certainty of evidence was assessed using the GRADE approach. Effect size using standardized mean differences assessed magnitude of change between pre- and postoperative ROM.

Results

In total, 23 studies were included evaluating 2,332 patients. Mean age ranged from 18 to 44.2 years. Flexion, internal rotation (IR), and external rotation (ER) were the predominantly measured ROMs reported in 91%, 100% and 65% of studies, respectively. Observed change following hip arthroscopy was considered significant in 57.1% (flexion), 74% (IR), and 20% (ER). Effect size of change in significantly improved ROMs were weak (16.7% flexion, 33.3% ER), moderate (58.3% flexion, 29.4% IR), and large (25% flexion, 64.7% IR, 66.7% ER). For goniometric assessment mean observed changes ranged as follows: flexion: 0.1° to 12.2°; IR: 3.6° to 21.9°; ER: –2.6° to 12.8°. For computed tomography–simulated assessment, the mean observed change ranged as follows: flexion: 3.0° to 8.0°; IR 9.3° to 14.0°.

Conclusions

Outcome studies demonstrate overall increased range of flexion and IR post-hip arthroscopy, with a moderate and large effect respectively. Change in ER is less impacted following hip arthroscopy. Certainty of evidence to support this observation is low. Current research evaluating changes in this functional ability is limited by a lack of prospective studies and non-standardized measurement evaluation techniques.

Level of Evidence

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

Revision Surgery and Progression to Total Hip Arthroplasty After Surgical Correction of Femoroacetabular Impingement: A Systematic Review

BACKGROUND

Femoroacetabular impingement (FAI) is a major cause of hip pain in young adults and athletes. Surgical treatment of FAI is recommended in cases of failed nonoperative treatment that have the typical clinical and radiographic findings. At present, the role of risk factors for revision surgery and progression to total hip arthroplasty (THA) in patients with FAI is still unclear.

PURPOSE

To investigate the possible association between (1) rate of revision and progression to THA and (2) patient characteristics, type of lesion, family history of hip disease, type of intervention, radiographic parameters, physical examination, and pre- and postoperative scores.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

The present systematic review was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. In October 2020, the main online databases were accessed. All articles concerning surgical correction for selected patients with FAI were accessed. Patient characteristics, type of intervention, radiographic parameters, physical examination, and pre- and postoperative scores were assessed. The outcomes of interest were the possible association between these variables and the rate of revision and subsequent progression to THA using a multivariate analysis through the Pearson product-moment correlation coefficient.

RESULTS

Data from 99 studies (9357 procedures) were collected. The median follow-up was 30.9 months (interquartile range, 24.0-45.0). The mean ± SD age was 33.4 ± 9.3 years; mean body mass index (BMI), 24.8 ± 4.8; percentage right side, 55.8% ± 8.0%; and percentage female sex, 47.5% ± 20.4%. The overall rate of revision was 5.29% (351 of 6641 patients), while the rate of subsequent progression to THA was 3.78% (263 of 6966 patients). Labral debridement (P < .0001), preoperative acetabular index (P = .01), and BMI (P = .03) all showed evidence of a statistically positive association with increased rates of THA. No other statistically significant associations were found between patient characteristics, type of lesion, family history of hip disease, type of intervention, radiographic parameters, physical examination, or pre- and postoperative scores and the rate of revision and/or progression to THA.

CONCLUSION

Although surgical procedures to treat FAI led to satisfactory outcomes, there was a revision rate of 5.29% in the 9357 procedures in the present systematic review. The rate of progression to THA after a median follow-up of 30 months was 3.78%. Patients who have a higher BMI and/or have a pathologic acetabular index and/or undergo labral debridement during correction of FAI are more at risk for a subsequent THA. We advocate additional education of this patient population in terms of expected outcomes and suggest surgical labral repair instead of debridement if needed.

Ten-Year Outcomes After Hip Arthroscopy in Patients With Femoroacetabular Impingement and Borderline Dysplasia

BACKGROUND

The role of hip arthroscopy in the treatment of patients with borderline hip dysplasia is controversial and evolving.

PURPOSE

To evaluate outcomes at a minimum 10-year follow-up in patients who underwent hip arthroscopy for femoroacetabular impingement in a hip with borderline dysplasia.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

All hips that underwent labral repair between June 2006 and March 2009 for femoroacetabular impingement with borderline dysplasia were included if they had a lateral center-edge angle of 20° to 25°, had primary hip arthroscopy for the diagnosis of femoroacetabular impingement, and were aged 18 to 70 years. Patients were excluded if they had previous hip surgery, avascular necrosis, or fracture. Kaplan-Meier survivorship was performed, with survivorship defined as avoidance of conversion to total hip arthroplasty (THA).

RESULTS

A total of 45 patients met the inclusion criteria, and 38 were contacted at a minimum 10 years postoperatively (84%; mean ± SD, 12 ± 1.3 years). There were 23 women and 15 men with an average age of 41 ± 9.6 years (range, 25-69). Twenty patients were ≥40 years of age. In this patient cohort, survivorship was 87% at 5 years and 79% at 10 years for conversion to THA. Of the 38 patients included, 9 were converted to THA (24%), and 3 required revision hip arthroscopy (7%). Patient age, Tönnis grade, microfracture of cartilage lesions, and Tönnis angle >15° were associated with conversion to THA. No statistically significant differences were found between those who underwent conversion to THA and those who did not regarding lateral center-edge angle, Sharp angle, or alpha angle. Significant improvements were seen at follow-up of 12 years (range, 10-13) for the modified Harris Hip Score (58 to 83; P = .002), Hip Outcome Score-Activities of Daily Living (70 to 87; P = .003), Hip Outcome Score-Sport (47 to 76; P = .004), and Western Ontario and McMaster Universities Osteoarthritis Index (31 to 10; P = .001). At follow-up, >80% maintained the minimal clinically important difference for the Hip Outcome Score (Activities of Daily Living and Sport) with no differences between patients aged <40 and ≥40 years.

CONCLUSION

Risk factors for conversion to THA after hip arthroscopy in the borderline dysplastic hip included older age, higher Tönnis grades, grade 4 chondral lesions that were microfractures, and Tönnis angle >15°. In those patients who did not convert to THA, improvement in outcome measures was seen at 10 years. Careful patient selection is critical to the success of this procedure.

Prevalence of Borderline Acetabular Dysplasia in Symptomatic and Asymptomatic Populations: A Systematic Review and Meta-analysis

Background:

Patients with borderline acetabular dysplasia are a controversial patient population in hip preservation, as some have primarily impingement-based symptoms and others have instability-based symptoms. Borderline dysplasia is most commonly defined as a lateral center-edge angle (LCEA) of 20° to 25°. However, its prevalence has not been well established in the literature.

Purpose:

To (1) define the prevalence of borderline hip dysplasia in the general population as well as in populations presenting with hip pain using a systematic review and meta-analysis of the literature and (2) describe differences between male and female patients as well as differences in prevalence from that of classic acetabular dysplasia.

Study Design:

Systematic review; Level of evidence, 3.

Methods:

A systematic review of the literature was performed using search terms to capture borderline dysplasia, or studies reporting prevalence by LCEA. The search yielded 1932 results, of which 11 articles met inclusion criteria and were included in the final systematic review. Studies were grouped by patient cohort as (1) asymptomatic general population, (2) asymptomatic targeted population (eg, athletes in a specific sport), and (3) symptomatic hip pain population. The reporting of prevalence rates by subject or by hip was recorded. In a study, the rates of borderline dysplasia were compared with those of classic acetabular dysplasia (LCEA, <20°).

Results:

The 11 studies included 19,648 hips (11,754 patients). In the asymptomatic general population, the pooled estimate of the prevalence of borderline dysplasia was 19.8% by subject and 23.3% by hip (range, 16.7%-46.0%). The targeted subpopulation group included 236 athletes with subgroups in ballet, football, hockey, volleyball, soccer, and track and field with prevalence ranging from 17.8% to 51.1%. The prevalence of borderline dysplasia in groups presenting with hip pain was 12.8% (range, 12.6%-16.0%). Borderline acetabular dysplasia was 3.5 times more common than classic acetabular dysplasia in the asymptomatic general population.

Conclusion:

This study demonstrated a prevalence of borderline dysplasia of 19.8% to 23.3% in the asymptomatic general population. Additionally, an estimated prevalence of 12.8% of hips in symptomatic patients highlights the common decision-making challenges in this population.

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

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

Return to Sport in Athletes With Borderline Hip Dysplasia After Hip Arthroscopy for Femoroacetabular Impingement Syndrome

BACKGROUND

Data on outcomes in patients with borderline hip dysplasia (BHD) who undergo hip arthroscopy remain limited, particularly in regard to return to sport (RTS).

PURPOSE

To evaluate outcomes in patients with BHD and their ability to RTS after hip arthroscopy for treatment of femoroacetabular impingement syndrome (FAIS).

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Consecutive patients with self-reported athletic activity and radiographic evidence of BHD, characterized by a lateral femoral center-edge angle (LCEA) between 18° and 25° and a Tönnis angle >10°, who underwent hip arthroscopy for FAIS between November 2014 and March 2017 were identified. Patient characteristics and clinical outcomes including the Hip Outcome Score-Activities of Daily Living (HOS-ADL), Hip Outcome Score-Sports Subscale (HOS-SS), modified Harris Hip Score (mHHS), international Hip Outcome Tool (iHOT-12), and visual analog scale (VAS) for pain and satisfaction were analyzed at minimum 2-year follow-up. In addition, all patients completed an RTS survey.

RESULTS

A total of 41 patients with a mean age and body mass index (BMI) of 29.6 ± 13.4 years and 25.3 ± 5.6, respectively, were included. Mean LCEA and Tönnis angle for the study population were 22.7°± 1.8° and 13.3°± 2.9°, respectively. A total of 31 (75.6%) patients were able to RTS after hip arthroscopy at a mean of 8.3 ± 3.2 months. A total of 14 patients (45.2%) were able to RTS at the same level of activity, 16 patients (51.6%) returned to a lower level of activity, and only 1 (3.2%) patient returned to a higher level of activity. Of the 11 high school and collegiate athletes, 10 (90.9%) were able to RTS. All patients demonstrated significant improvements in all patient-reported outcome measures (PROMs) as well as in pain scores at a mean of 26.1 ± 5.4 months after surgery. Patients who were able to RTS had a lower preoperative BMI than patients who did not RTS. Analysis of minimum 2-year PROMs demonstrated better HOS-ADL, HOS-SS, mHHS, iHOT-12, and VAS outcomes for pain in patients able to RTS versus those who did not RTS (P < .05).

CONCLUSION

Of the patients with BHD studied here, 75.6% of patients successfully returned to sport at a mean of 8.3 ± 3.2 months after hip arthroscopy for FAIS. Of the patients who successfully returned to sport, 45.2% returned at the same level, and 3.2% returned at a higher activity level.

Arthroscopic Treatment of Labral Tears in Patients with Borderline Developmental Dysplasia of the Hip: A Retrospective Study with Mean 5.8 Years Follow-Up

Objective

To retrospectively assess the mid‐term clinical and radiological results of hip arthroscopic treatment of labral tears in patients with borderline developmental dysplasia of the hip (BDDH).

Methods

From January 2010 and December 2019, data were retrospectively reviewed for all patients who underwent arthroscopic surgery of the hip for the treatment of intra‐articular abnormalities. Only the Patients who had borderline developmental dysplasia (BDDH) were included. All operations were performed by two senior surgeons, the arthroscopic treatment including labral repair, labral debridement, minimal acetabuloplasty, femoroplasty and capsular closure. The evaluation consisted of pain evaluation (visual analog scale [VAS]), the modified Harris hip score (MHHS), range of motion, the radiological evaluation of plain film and MRI analysis of the hip joint. The plain film evaluation included anteroposterior views of the pelvis to assess lateral center‐edge angle (LCEA) and acetabular inclination (AI), frog‐leg lateral views of the hip to assess α angle.

Results

There were 34 patients (36 hips) ultimately enrolled in this study. The follow‐up duration of the patients were minimal 2 years (average, 69.2 months) postoperatively. The patient group included seven men and 27 women, the mean age at the time of surgery was 30.9 years. The mean BMI was 22.3 kg/m². From the pre‐operative status to the final follow‐up visit, mean mHHS score increased from 64.5 to 92.7, mean VAS score decreased from 6.8 to 1.3. All scores exhibited statistically significant differences (P < 0.001). The mean LCEA decreased from 22.9° to 22.7°, the mean AI decreased from 7.7° to 7.6°. Which all showed no significant differences compared with the final follow‐up to the pre‐operative status (P > 0.05). However, the mean α angle was significantly decreased from 48.3° to 40.1° (P < 0.001). We encountered no significant complications such as infection, deep venous thrombosis, fluid extravasation, or permanent nerve injury. One patient (2.94%) underwent revision periacetabular osteotomies (PAO) because of subluxation of the hip joint with permanent pain after 6 months failed conservative treatment.

Conclusion

Arthroscopic treatment of labral tears in patients with BDDH may provide safe and durable favorable results at midterm follow‐up. The best outcome could be expected in patients with labral repair and closure of the capsule with strict patient selection criteria.

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

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

Level of evidence: Level III, diagnostic study.

Arthroscopic Treatment of Femoroacetabular Impingement in Patients With and Without Borderline Developmental Dysplasia of the Hip: A Systematic Review and Meta-analysis

Background:

Based on previous studies, it is difficult to discern whether patients who have femoroacetabular impingement (FAI) with borderline developmental dysplasia of the hip (BDDH) would benefit from arthroscopy when compared with patients without BDDH.

Purpose:

To evaluate the existing comparative literature on arthroscopic findings, procedures, patient-reported outcomes (PROs), and failures in patients who have FAI with BDDH compared with those without BDDH.

Study Design:

Systematic review; Level of evidence, 3.

Methods:

The PubMed, Embase, and Ovid databases were searched for studies published up to August 31, 2019, that reported outcomes after arthroscopy to treat patients who had FAI with BDDH. Included studies were required to have patients diagnosed with FAI and BDDH who were treated arthroscopically and compared with control patients (FAI without BDDH). Arthroscopic findings, PROs, and revision or total hip arthroplasty (THA) conversion rates were compared between groups.

Results:

Included in the review were 4 articles (933 patients). Patients who had FAI with BDDH were defined as having a lateral center-edge angle (LCEA) of either 18° to 25° or 20° to 25°; for control patients, the maximum LCEA was 40°. Across the studies, there were 224 patients who had FAI with BDDH compared with 709 control patients; the mean follow-up time ranged from 21.6 to 31.3 months among the groups. Improvements were shown across all PROs in each study. Random-effects meta-analysis indicated no statistically significant differences in postoperative PROs, the risk for revision surgery, or conversion to THA between the patients who had FAI with versus without BDDH.

Conclusion:

The results of the current review indicated that hip arthroscopy produced similar short-term outcomes between patients who had FAI with versus without BDDH.

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.

Complications of hip preserving surgery

Preoperative evaluation of the pathomorphology is crucial for surgical planning, including radiographs as the basic modality and magnetic resonance imaging (MRI) and case-based additional imaging (e.g. 3D-CT, abduction views).

Hip arthroscopy (HAS) has undergone tremendous technical advances, an immense increase in use and the indications are getting wider. The most common indications for revision arthroscopy are labral tears and residual femoroacetabular impingement (FAI).

Treatment of borderline developmental dysplastic hip is currently a subject of controversy. It is paramount to understand the underlining problem of the individual hip and distinguish instability (dysplasia) from FAI, as the appropriate treatment for unstable hips is periacetabular osteotomy (PAO) and for FAI arthroscopic impingement surgery.

PAO with a concomitant cam resection is associated with a higher survival rate compared to PAO alone for the treatment of hip dysplasia. Further, the challenge for the surgeon is the balance between over- and undercorrection.

Femoral torsion abnormalities should be evaluated and evaluation of femoral rotational osteotomy for these patients should be incorporated to the treatment plan.

Cite this article: EFORT Open Rev 2021;6:472-486. DOI: 10.1302/2058-5241.6.210019

Medium-term results of arthroscopic treatment for femoroacetabular impingement

INTRODUCTION

Femoroacetabular impingement (FAI) is a dynamic pathomechanical process of the femoral head-neck junction. Arthroscopic surgery for FAI has increased exponentially in the last decade, and this trend is expected to increase.

SOURCE OF DATA

Recent published literatures.

AREAS OF AGREEMENT

FAI promotes quick rehabilitation and low complication rates in the short-term follow-up.

AREAS OF CONTROVERSY

Despite the growing interest on arthroscopic surgery for FAI, current evidence regarding the medium- and long-term role of arthroscopy are unsatisfactory.

GROWING POINTS

Systematically summarize current evidences, analyse the quantitative available data and investigate the medium- and long-term outcomes of arthroscopic surgery for FAI.

AREAS TIMELY FOR DEVELOPING RESEARCH

Arthroscopic surgery achieves very satisfactory outcomes for patients with FAI at a mean follow-up of 4 years.

Reconstruction of the Hip in Multiple Hereditary Exostoses

The hip joint involvement in multiple hereditary exostoses (MHE) occurs in 30-90%, causing pain and limitation of motion by femoroacetabular impingement, coxa valga, acetabular dysplasia, hip joint subluxation, and osteoarthritis. The purpose of this study was to investigate the clinical and radiographic outcomes of ten hips in seven patients treated by surgical dislocation and corrective osteotomies between 2004 and 2009. Surgical dislocation and excision of the osteochondromas and varus intertrochanteric osteotomies were performed in all cases when the neck-shaft angle was > 150°. Common sites of osteochondromas were medial, posterior, and anterior neck of the femur. Neck-shaft angle of the femur was improved from a mean of 157° to 139°, postoperatively. On an average, the center-edge angle improved from 20° to 30° postoperatively. We believe that Ganz's safe surgical dislocation technique is the preferred treatment of MHE. This safeguards the circulation of the femoral head and the osteochondromas can be resected under direct vision. It can be combined with additional corrective osteotomies because the hip affected by MHE is frequently associated with dysplastic changes which can result in premature osteoarthritis.

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.

Can the Femoro-Epiphyseal Acetabular Roof (FEAR) Index Be Used to Distinguish Dysplasia from Impingement?

BACKGROUND

Classifying hips with structural deformity on the spectrum from impingement to dysplasia is often subjective and frequently inexact. Currently used radiographic measures may inaccurately predict a hip's morphological stability in borderline hips. A recently described radiographic measure, the Femoro-Epiphyseal Acetabular Roof (FEAR) index, has demonstrated an ability to predict stability in the borderline hip. This measure is attractive to clinicians because procedures can be used on the basis of a hip's pathomechanics. This study was designed to further validate and characterize the FEAR index in a skeletally immature population, in hips with dysplasia/femoroacetabular impingement (FAI), and in asymptomatic hips.

QUESTIONS/PURPOSES

(1) What are the characteristics of the FEAR index in children and how does the index change with skeletal maturation? (2) How does the FEAR index correlate with clinical diagnosis and surgical treatment in a large cohort of symptomatic hips and asymptomatic controls? (3) How does the FEAR index correlate with clinical diagnosis in the borderline hip (lateral center-edge angle [LCEA] 20°-25°) group?

METHODS

A total of 220 participants with symptomatic investigational hips with a clinical diagnosis of dysplasia or FAI between January 2008 and January 2018 were retrospectively collected from the senior author's practice. Investigational hips were excluded if they had any femoral head abnormalities preventing LCEA measurement (for example, Perthes disease), Tönnis osteoarthritis grade greater than 1, prior hip surgery, or prior femoral osteotomy. In the 220 participants, 395 hips met inclusion criteria. Once exclusion criteria were applied, 15 hips were excluded due to prior hip surgery or prior femoral osteotomy, and 12 hips were excluded due to femoral head deformity. A single hip was then randomly selected from each participant, resulting in 206 investigational hips with a mean age of 13 ± 3 years. Between January 2017 and December 2017, 70 asymptomatic control participants were retrospectively collected from the senior author's institutional trauma database. Control hips were included if the AP pelvis film had the coccyx centered over the pubic symphysis and within 1 to 3 cm of the superior aspect of the symphysis. Control hips were excluded if there was any fracture to the pelvis or ipsilateral femur or the participant had prior hip/pelvis surgery. After exclusion criteria were applied, 16 hips were excluded due to fracture. One hip was then randomly selected from each participant, resulting in 65 control hips with a mean age of 16 ± 8 years. Standardized standing AP pelvis radiographs were used to measure the FEAR index, LCEA, and Tönnis angle in the investigational cohort. Standardized false-profile radiographs were used to measure the anterior center-edge angle (ACEA) in the investigational cohort. Two blinded investigators measured the FEAR index with an intraclass correlation coefficient of 0.92 [95% CI 0.84 to 0.96]. Question 1 was answered by comparing the above radiographic measures in age subgroups (childhood: younger than 10 years; adolescence: 10 to 14 years old; maturity: older than 14 years) of dysplastic, FAI, and control hips. Question 2 was answered by comparing the radiographic measures in all dysplastic, FAI, control hips, and a subgroup of operatively or nonoperatively managed dysplasia and FAI hips. Question 3 was answered by comparing the radiographic measures in borderline (LCEA 20°-25°) dysplastic, FAI, and control hips.

RESULTS

The FEAR index was lower in older dysplastic of hips (younger than 10 years, 6° ± 9°; 10 to 14 years, 4° ± 10°; older than 14 years, 5° ± 9°; p < 0.001) and control hips (younger than 10 years, -6° ± 5°; 10 to 14 years, -15° ± 4°; older than 14 years, -16° ± 7°; p < 0.001). The diagnosis and age groups were independently correlated with the FEAR index (p < 0.001). The relationship between the FEAR index and diagnosis remained consistent in each age group (p = 0.11). The FEAR index was higher in all dysplastic hips (mean 5° ± 10°) than in asymptomatic controls (mean -13° ± 7°; p < 0.001) and FAI hips (mean -10° ± 11°; p < 0.001). Using -1.3° as a cutoff for FAI/control hips and dysplastic hips, 81% (112 of 139) of hips with values below this threshold were FAI/control, and 89% (117 of 132) of hips with values above -1.3° were dysplastic. The receiver operator characteristics area under the curve (ROC-AUC) was 0.91. Similarly, the FEAR index was higher in borderline dysplastic hips than in both asymptomatic borderline controls (p < 0.001) and borderline FAI hips (p < 0.001). Eighty-nine percent (33 of 37) of hips with values below this threshold were FAI/control, and 90% (37 of 41) of hips with values above -1.3° were dysplastic. The ROC-AUC for borderline hips was 0.86.

CONCLUSION

The FEAR index was associated with the diagnosis of hip dysplasia and FAI in a patient cohort with a wide age range and with varying degrees of acetabular deformity. Specifically, a FEAR index greater than -1.3° is associated with a dysplastic hip and a FEAR index less than -1.3° is associated with a hip displaying FAI. Using this reliable, developmentally based radiographic measure may help hip preservation surgeons establish a correct diagnosis and more appropriately guide treatment.

LEVEL OF EVIDENCE LEVEL

III, diagnostic study.

Evaluation of outcome reporting trends for femoroacetabular impingement syndrome- a systematic review

PURPOSE

The aim of this systematic review was to evaluate the trends in the literature regarding surgical treatment for femoroacetabular impingement syndrome (FAIS) and to present which patient-reported outcome-measures (PROMs) and surgical approaches are included.

METHODS

This systematic review was conducted with the PRISMA guidelines. The literature search was performed on PubMed and Embase, covering studies from 1999 to 2020. Inclusion criteria were clinical studies with surgical treatment for FAIS, the use of PROMs as evaluation tool and studies in English. Exclusion criteria were studies with patients < 18 years, cohorts with < 8 patients, studies with primarily purpose to evaluate other diagnoses than FAIS and studies with radiographs as only outcomes without using PROMs. Data extracted were author, year, surgical intervention, type of study, level of evidence, demographics of included patients, and PROMs.

RESULTS

The initial search yielded 2,559 studies, of which 196 were included. There was an increase of 2,043% in the number of studies from the first to the last five years (2004-2008)-(2016-2020). There were 135 (69%) retrospective, 55 (28%) prospective and 6 (3%) Randomized Controlled Trials. Level of evidence ranged from I-IV where Level III was most common (44%). More than half of the studies (58%) originated from USA. Arthroscopic surgery was the most common surgical treatment (85%). Mean follow-up was 27.0 months (± 17 SD), (range 1.5-120 months). Between 1-10 PROMs were included, and the modified Harris Hip Score (mHHS) was most commonly used (61%).

CONCLUSION

There has been a continuous increase in the number of published studies regarding FAIS with the majority evaluating arthroscopic surgery. The mHHS remains being the most commonly used PROM.

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

Background:

Femoroacetabular impingement and acetabular dysplasia have gained increased attention as nonarthritic sources of pain and dysfunction in young, active patients. To date, no standardized approach to the diagnostic evaluation of nonarthritic hip pain has been identified, as previous work has focused on the diagnostic evaluation and management of patients with femoroacetabular impingement undergoing hip arthroscopy.

Purpose:

To explore the standard diagnostic evaluation practice of experts in the field of hip preservation surgery and combine their expertise through the Delphi method to form a standardized approach to the diagnostic evaluation of patients with nonarthritic hip pain.

Study Design:

Consensus statement.

Methods:

An expert panel made up of 18 orthopaedic surgeons with extensive experience in the treatment of nonarthritic hip disorders participated in this Delphi study. The Delphi panelists were presented with 4 clinical vignettes representing a spectrum of patients with nonarthritic hip pain. Three iterative survey rounds were presented to the panelists based on these clinical vignettes, and a 3-step classic Delphi method was used to establish consensus techniques in the diagnostic evaluation of nonarthritic hip pain.

Results:

Total (100%) participation was gained, with all 18 experts completing all 3 Delphi survey rounds. Consensus (≥75% support) was achieved for some, if not all, vignettes for each of the following diagnostic domains: historical features, physical examination, radiographic sequences, radiographic interpretation, cross-sectional imaging, and ancillary diagnostics.

Conclusion:

In this Delphi study, we identified standardized diagnostic treatment approaches as derived from expert opinion for patients with nonarthritic hip pathomorphologies.

Increased range of motion but otherwise similar clinical outcome of arthroscopy over open osteoplasty for femoroacetabular impingement at midterm follow-up: A systematic review

BACKGROUND

A systematic review was conducted comparing patient reported outcomes measures (PROMs), functional scores, and the rate of complications between arthroscopic and open treatment for femoroacetabular impingement (FAI) at mid-term follow-up.

MATERIAL AND METHODS

This systematic review was performed according to the PRISMA guidelines. The literature search was performed in October 2020. All clinical trials treating FAI using open osteoplasty or arthroscopic surgery were considered for inclusion. Only articles reporting >12 months follow-up were included.

RESULTS

Data from 97 articles (9981 procedures) were collected. At a mean 19.2 months follow-up there was no difference between the two cohorts. At a mean follow-up of 38 months, the external rotation was increased in the arthroscopic group (P < 0.0001). The modified Harris Hip Score scored greater in favour of the open osteoplasty group (P = 0.04), as did the Hip Outcome Score - Activities of Daily Living subscale (P = 0.01). At a mean 45.1 months the arthroscopic group presented greater external rotation (P < 0.0001) and SF-12 Mental (P = 0.04). The modified Harris Hip Score was greater in favour of the open osteoplasty group (P = 0.03), as was the HOS-ADL (P = 0.01). Regarding complications, the arthroscopic group experienced lower rates of subsequent revisions (P < 0.0001).

CONCLUSION

Based on the significant reduction of revisions-rate and significant increase in range of motion, arthroscopy treatment for the management of FAI may be recommended.

Femoral Version in Hip Arthroscopy: Does it Matter?

Femoral version is extremely variable between patients presenting with femoroacetabular impingement (FAI). Careful and routine measurement of femoral anteversion is essential in comprehensive preoperative planning. In general, low degrees of femoral version can lead to anterior impingement (especially on the subspine and distal medial femoral neck). High degrees of anteversion can be seen in the setting of acetabular dysplasia and can lead to anterior hip instability and or posterior impingement. In this article, the authors will discuss the role of routine femoral version management for optimal outcomes after hip arthroscopy for FAI.

Editorial Commentary: "The Earth is Not Flat": Progressing From Plain Radiographs to Three-Dimensional Imaging When Evaluating Hip Disorders

Dysplastic hip morphologies have received increasing attention in the hip preservation community. Defining and characterizing "transitional acetabular coverage" or "borderline" dysplasia has been extraordinarily challenging, and these hips have been lumped together based on focal radiographic measurements such as the lateral center edge and Tonnis angles. Some of these hips are treated with arthroscopy and some with corrective osteotomies without definitive patient-related outcome measure winners in our literature. Three-dimensional imaging evaluation of these hips with regard to acetabular and femoral-sided anatomy will be required to more clearly define any consistent anatomic variants and their respective optimal surgical approaches.

Computed Tomography-Based Three-Dimensional Analyses Show Similarities in Anterosuperior Acetabular Coverage Between Acetabular Dysplasia and Borderline Dysplasia

PURPOSE

(1) To compare the acetabular coverage between dysplasia, borderline dysplasia, and control acetabulum in a quantitative 3-dimensional manner; and (2) to evaluate correlations between the radiologic parameters and the 3-dimensional zonal-acetabular coverage.

METHODS

We reviewed contralateral hip computed tomography images of patients 16 to 60 years of age who underwent 1 of 3 types of surgeries: eccentric rotational acetabular osteotomy, curved intertrochanteric varus osteotomy, and total hip replacement with minimum 1-year follow-up from January 2013 to April 2018. A point-cloud model of the acetabulum created from computed tomography was divided into 6 zones. Three-dimensional acetabular coverage was measured radially at intervals of 1°. Mean radial acetabular coverage for each zone was named ZAC (zonal acetabular coverage) and was compared among the 3 subgroups (control: 25° ≤lateral center-edge angle [LCEA] <40°; borderline: 20° ≤LCEA <25°; and dysplasia: LCEA ≤20°) statistically. Further, the correlations between the ZAC in each zone and the LCEA were analyzed using Pearson's correlation coefficient.

RESULTS

One-hundred fifteen hips were categorized as control (36 hips), borderline (32 hips), and dysplasia (47 hips). The mean anterocranial ZAC in the borderline (87.5 ± 5.7°) was smaller than that in the control (92.6 ± 5.9°, P = .005) but did not differ compared with the dysplasia (84.5 ± 7.6°, P = .131). In contrast, the anterocaudal (71.2 ± 5.0°), posterocranial (85.0 ± 6.4°), and posterocaudal (82.4 ± 4.5°) mean ZACs in the borderline were not different from those in the control (anterocaudal, 74.3 ± 4.6°, P = .090; posterocranial, 87.9 ± 4.3°, P = .082; posterocaudal, 85.1 ± 5.0°, P = .069) respectively. Although there was a very strong positive correlation with supra-anterior ZAC and LCEA (r = 0.750, P < .001), the correlation between the anterocranial ZAC and LCEA was relatively weak (r = 0.574, P < .001).

CONCLUSIONS

The anterosuperior acetabular coverage in the borderline dysplastic acetabulum is more similar to the dysplastic acetabulum than to the normal acetabulum.

CLINICAL RELEVANCE

This study emphasizes the importance of evaluating not only the lateral but also the anterior coverage in borderline 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.

Three-dimensional hip joint congruity evaluation of the borderline dysplasia: Zonal-acetabular radius of curvature

In theory, a hemispherical acetabulum provides the ideal hip congruity in any hip position. However, it remains unknown how the three-dimensional acetabular morphology of borderline dysplastic and frank dysplastic hips compare to normal hips. This study inquires if borderline dysplastic zonal-acetabular curvatures in the anterior, superior, and posterior zones are different from normal or dysplastic hips three-dimensionally. One-hundred and fifteen hips, grouped as control (25°≤ LCEA <40°), 36 hips; borderline (20°≤ LCEA <25°), 32 hips; dysplasia (LCEA ≤20°), 47 hips were analyzed. The radii of acetabular curvature for the anterior, superior, and posterior zones were calculated as the zonal-acetabular radius of curvature (ZARC). The mean acetabular roof obliquity of the borderline (10.6 ± 4.3 [SD]°) was significantly larger than the control (3.0° ± 5.4°; P < .001) and smaller than the dysplasia (19.3° ± 5.7°; P < .001). Although the mean acetabular anteversion angle of the borderline (21.3° ± 3.7°) was significantly larger than control (17.9 ± 3.5°; P = .001), that of the borderline was not different from the dysplasia (23.3° ± 4.0°; P = .053). The mean anterior ZARC in the borderline (29.8 ± 2.6 mm) was significantly larger than the control (28.0 ± 2.2 mm; P = .011) and smaller than the dysplasia (31.5 ± 2.7 mm; P = .009). The mean superior ZARC in the borderline (25.7 ± 3.0 mm) was not different from the control (25.9 ± 2.2 mm; P = .934) or the dysplasia (25.8 ± 2.5 mm; P = .991). Although the mean posterior ZARC in the borderline (27.2 ± 2.5 mm) was not different from the control (26.4 ± 1.9 mm; P = .455), that of the borderline group was significantly smaller than the dysplasia (30.4 ± 3.3 mm; P < .001); that is, the severity of lateral under-coverage affects the anterior and/or posterior zonal-acetabular curvature.

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

PURPOSE

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.

METHODS

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).

RESULTS

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 50 months in the borderline hip dysplasia cohort, and 52 months 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.

CONCLUSION

With strict patient selection criteria, hip arthroscopy may be a beneficial approach in patients with borderline hip dysplasia.

Editorial Commentary: Arthroscopy for Borderline Developmental Dysplasia of the Hip: Selection Determines the Outcomes

Although the literature has presented results that favored arthroscopic procedures in treating borderline developmental dysplasia of the hip (BDDH), it remains controversial whether arthroscopic surgery would be better than periacetabular osteotomy for BDDH. Instead of a debate on the application of arthroscopy, the issue worthy of discussion should be distinguishing suitable BDDH candidates for hip arthroscopy. First, identification of patients with real BDDH is critical for making management choices. Second, it should be distinguished whether the major symptoms result from mechanical lesions or functional hip instability. Third, once hip arthroscopy is suggested for BDDH patients, relative contraindications such as advanced age and osteoarthritis should be taken into consideration, in addition to labral repair and capsular closure or plication intraoperatively. In conclusion, more long-term and high-grade evidence is still demanded to end the debate, but we believe that an individualized management strategy based on an accurate diagnosis and comprehensive assessment will bring optimal outcomes for BDDH patients.

Hip Arthroscopy and Borderline Developmental Dysplasia of the Hip: A Systematic Review

PURPOSE

To provide an up-to-date evidence-based review of hip arthroscopy for patients with borderline developmental dysplasia of the hip (BDDH).

METHODS

Literature describing hip arthroscopy in patients with BDDH was systematically identified from PubMed, EMBASE, and Cochrane Library using the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. All studies that involved BDDH and not just those reporting their clinical outcomes were included. Methodological Index for Non Randomized Studies criteria and Newcastle-Ottawa Scale were used to assess the quality of studies. The definition of BDDH, operative technique, correlation with labrum and/or cartilage lesions, outcome, and factors associated with poor outcome were collected and analyzed.

RESULTS

Assessment of the articles yielded 28 studies involving 1502 hips that were included for final analysis. There were no studies with a high risk of bias. BDDH was defined as lateral center-edge angle of 20° to 25° in most studies. Hip arthroscopy for BDDH showed an improvement in the weighted mean postoperative modified Harris Hip Score, from 60.2 to 81.7, a relatively high rate of acquisition of minimal clinically important difference of 79.5% to 87%, and had 1.0% rate of complications. Eleven studies reported on all the patients undergoing a capsular plication. Four studies reported that BDDH was associated with cartilage damage on the femoral head. Age older than 35 or 42 years and ≥20° of femoral anteversion were reported as risk factors for poor outcomes.

CONCLUSIONS

Hip arthroscopy for BDDH with capsular plication provides improvement in patient-reported outcome measures and a relatively high rate of acquisition of minimal clinically important difference with a low rate of complications in the shorter term. BDDH may be associated with cartilage damage on the femoral head. Female sex is a factor related to good outcomes, whereas older age, excessive femoral anteversion, and anterior undercoverage of acetabulum are risk factors related to poorer outcomes.

LEVEL OF EVIDENCE

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

The Hip Suction Seal, Part II: The Effect of Rim Trimming, Chondrolabral Junction Separation, and Labral Repair/Refixation on Hip Distractive Stability

BACKGROUND

The acetabular labrum contains free nerve endings, and an unstable labrum can result in increased femoral head movement during hip motion. This can be caused by chondrolabral junction (CLJ) separation, especially in association with pincer-type femoroacetabular impingement, and may contribute to hip pain.

HYPOTHESIS

Rim resection alone has no effect on suction seal biomechanics. Further, separation of the CLJ changes hip suction seal biomechanics when compared with those of the native state, whereas repair and refixation with suture anchors restore these biomechanical parameters.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 12 fresh-frozen human cadaveric hips were used in this study. Hips were mounted in a saline bath on a dynamic tensile testing machine and were distracted at a rate of 0.5 mm/s from neutral position. A total of 3 parameters (force, displacement, and intra-articular pressure) were measured throughout testing. Before testing, hips were randomly allocated to 1 of 2 groups: 1 that included the CLJ separation (CLJ Cut group) and 1 that did not (CLJ Intact group). Hips were tested in the following states: (1) native, (2) rim trimming, (3) separated CLJ (CLJ Cut group only), and (4) labral repair/refixation. For each group a linear mixed-effects model was used to compare biomechanical parameters between states.

RESULTS

Rim trimming did not affect any suction seal parameters relative to those of the native state. In the CLJ Cut group, no significant difference in distance to break the suction seal was observed for any states compared with that of the native state. In the CLJ Intact group, the distance to break the suction seal was significantly shorter in the labral refixation state (1.8 mm) than the native state (5.6 mm; P = .002). The maximum distraction force (62.1 ± 54.1 N) and the peak negative pressure (-36.6 ± 24.2 kPa) of the labral repair/refixation state were significantly lower than those of the native state in both groups (93.4 ± 41.7 N, P = .01; -60.7 ± 20.4 kPa, P = .02).

CONCLUSION

Rim trimming did not change the biomechanical properties of the labral suction seal. Labral refixation resulted in a shorter distance to break the labral suction seal. This indicates that labral mobility is reduced by the labral refixation procedure, which could be beneficial in postoperative pain relief and labral healing.

CLINICAL RELEVANCE

The labral refixation reduced labral mobility, which could be beneficial for both pain relief and labral healing to the acetabulum after pincer-type femoroacetabular impingement resection.

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

INTRODUCTION

Since 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 METHODS

We 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.

RESULTS

Seven 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).

CONCLUSION

Hip 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.