Clinical and Radiographic Predictors for Worsened Clinical Outcomes After Hip Arthroscopic Labral Preservation and Capsular Closure in Developmental Dysplasia of the Hip

Trends in hip preservation surgery in Japan from 2014 to 2019 with a focus on hip arthroscopic surgery

Secondary hip osteoarthritis due to hip dysplasia is common among Japanese populations. This study aimed to investigate the number of hip preservation surgeries performed in Japan and assess trends, by age and sex, from 2014 to 2019, focusing on hip arthroscopic surgery, based on the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB). We downloaded the files 'Number of calculations by division, sex, and age group' under 'operation (code K)' from 2014 to 2019 from the NDB Open Data Japan database. Data on hip preservation surgeries were extracted, including the number for each surgical procedure and its incidence per year, calculated as the number of surgeries performed for each 10-year age group and by sex, regarding hip arthroscopic surgery. Overall, 14 891 hip preservation surgeries were performed in Japan over the study period, with pelvic osteotomy being the most common procedure. Although the incidence of hip preservation surgeries decreased from 2014 to 2019, there was a specific 1.54-fold higher incidence in hip arthroscopic procedures in 2019 compared to 2014. Hip arthroscopic labral repair was performed more frequently than synovectomy. The highest incidence of hip arthroscopic surgery was in the 40- to 49-years age group, with no difference in incidence between sexes (P = 0.951). In Japan, pelvic osteotomy was performed more often as a hip preservation surgery than hip arthroscopic surgery. Although hip arthroscopic surgery was developed in Japan, its use has not increased from 2017 to 2019.

Joint instability in patients with borderline developmental dysplasia of the hip

BACKGROUND

The treatment strategy for developmental dysplasia of the hip is determined based on the lateral center-edge angle. Nonetheless, an evaluation of joint instability may be important in determining the treatment strategy. This study classified the displacement patterns of the femoral head center during hip abduction.

METHODS

Ten patients with borderline developmental dysplasia of the hip, 10 patients with developmental dysplasia of the hip, and 10 patients with normal hips were analyzed. Image matching was performed using X-ray images of hip abduction with a three-dimensional hip model. The displacement of the femoral head center and its trajectory length were measured. A cluster analysis was conducted to classify the displacement pattern of the femoral head center, and trajectory lengths were compared.

FINDINGS

Displacement was classified into three patterns: medialization, hinge abduction, and centering. Patients with borderline developmental hip dysplasia exhibited all three patterns. Almost all patients with developmental dysplasia of the hip showed medialization and hinge abduction, whereas all normal patients had the centering type. The mean trajectory length indices for the medialization and hinge abduction types were significantly longer than those for the centering type (P = 0.01 and P = 0.016, respectively).

INTERPRETATION

Borderline developmental dysplasia of the hip is a heterogeneous condition characterized by varying hip instability levels. Our findings suggest that uniform evaluation based on the lateral center-edge angle is inappropriate and that joint instability must be evaluated in each patient with borderline developmental dysplasia of the hip.

Biomechanical Analysis of Hip Braces after Hip Arthroscopic Surgery for Femoroacetabular Impingement Syndrome: An Observational Study

Currently, hip braces are recommended and typically worn by femoroacetabular impingement (FAI) patients after hip arthroscopic surgery. However, there is currently a lack of literature regarding the biomechanical effectiveness of hip braces. The purpose of this study was to investigate the biomechanical effect of hip braces after hip arthroscopic surgery for FAI. Overall, 11 patients who underwent arthroscopic FAI correction and labral preservation surgery were included in the study. Standing-up and walking tasks in unbraced and braced conditions were performed at 3 weeks postoperatively. For the standing-up task, videotaped images of the hip's sagittal plane were recorded while patients stood from a seated position. After each motion, the hip flexion-extension angle was calculated. For the walking task, acceleration of the greater trochanter was measured using a triaxial accelerometer. For the standing-up motion, the mean peak hip flexion angle was found to be significantly lower in the braced condition than in the unbraced condition. Furthermore, the mean peak acceleration of the greater trochanter was significantly lower in the braced condition than in the unbraced condition. Patients undergoing arthroscopic FAI correction surgery would benefit from usage of a hip brace in terms of protecting repaired tissues during early postoperative recovery.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

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

Radiographic Parameters of Adult Hip Dysplasia

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

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.

Hip arthroscopic management for treating a rhythmic gymnast with a large bone cyst at the femoral head in the setting of hip dysplasia—a case report

Recent literature lacks a clear understanding of how to manage bone cysts associated with hip dysplasia. This article aimed to report a case of hip dysplasia in a rhythmic gymnast surgically managed with arthroscopic retrograde bone grafting, labral repair, cam osteoplasty, double shoelace capsular closure and endoscopic shelf acetabuloplasty. A 20-year-old female college rhythmic gymnast presented complaining of right hip pain and discomfort for the past 2 months. This case report describes the use of the CROSSTRAC guide system to perform retrograde bone grafting to treat the bone cyst at the femoral head arthroscopically. Hip arthroscopic retrograde bone grafting, labral repair, cam osteoplasty, double shoelace capsular closure and endoscopic shelf acetabuloplasty are less invasive and beneficial for the treatment of bone cysts of the femoral head associated with hip dysplasia in symptomatic rhythmic gymnasts.

Central acetabular osteophytes (CAO) are more prevalent in the borderline developmental dysplastic hip (BDDH) patients: a propensity-score matched CT study

Background

The acetabular fossa often showing the first signs of degeneration, Central acetabular osteophytes (CAO) have been increasingly recognized during hip arthroscopy. The purpose of this study was to investigate the condition of CAO in BDDH hips and compare cotyloid fossa size between the BDDH and the non-BDDH hips on CT images.

Methods

We performed a retrospective analysis of prospectively collected data of hip CT images of FAI or labral injury patients. A 1:2 propensity-score matched observational study comparing the linear length of cotyloid fossa was analyzed. Cotyloid fossa width (CFW) and cotyloid notch width (CNW) were measured on axial images, cotyloid fossa height (CFH) and cotyloid fossa depth (CFD) were measured on coronal images. Within the CAO patients, we performed central acetabular decompression (CAD) and then observed the morphology change in fossa.

Results

Propensity-score matching yielded 61 BDDH hips and 122 non-BDDH hips. BDDH hips had a higher prevalence of CAO and a decreased linear length of cotyloid fossa (CFW, CFH and CNW). In the BDDH group, 33 hips underwent CAD, postoperative CFW, CFH and CNW were significantly increased (p < .001 for all), and had no statistical difference compared with the non-BDDH hips (p = .193, p = .132, p = .421, respectively).

Conclusion

BDDH hips had a significantly higher prevalence of CAO than adequate acetabular coverage hips. After the procedure of CAD, BDDH hips were found to have acetabular parameters (CFW, CFH, CNW) and were restored to that of the control hips.

Endoscopic Shelf Acetabuloplasty Concomitant With Labral Repair, Cam Osteoplasty, and Capsular Plication to Treat Acetabular Dysplasia in Artistic Athletes: A Case Series

Background:

Knowledge of clinical outcomes and return to artistic activities after endoscopic shelf acetabuloplasty (ESA) for acetabular dysplasia in artistic athletes is lacking.

Hypothesis:

Hip arthroscopic surgery including ESA will enable artistic athletes to return to their activities with a high success rate, significantly improved acetabular coverage, and preserved joint cartilage.

Study Design:

Case series; Level of evidence, 4.

Methods:

We reviewed 28 hips in 23 female artistic athletes (14 ballet, 9 rhythmic gymnastics, 4 dance, and 1 baton twirling) who underwent arthroscopic labral preservation, capsular plication, and ESA. Their mean age was 25.8 ± 10.2 years. Preoperatively, all patients had generalized joint laxity (Beighton score, 7.1 ± 1.8). We evaluated preoperative and postoperative radiographs and outcome scores including the modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), International Hip Outcome Tool 12 (iHOT-12), Vail Hip Score (VHS), and Hip Outcome Score–Sports (HOS— Sports). Statistical analysis was performed using paired t tests and Bonferroni correction.

Results:

The mean follow-up was 32.5 ± 12.5 months. The mean lateral center-edge angle significantly increased from preoperatively (15.7° ± 5.3°) to postoperatively (39.8° ± 8.2°; P < .001) and at the final follow-up (33.7° ± 8.6°; P < .001). The vertical-center-anterior angle significantly improved from preoperatively (16.2° ± 8.8°) to final follow-up (33.6° ± 8.0°; P < .001). All hips maintained a Tönnis grade of 0 or 1 at the final follow-up. Overall, 20 patients (87%) were able to return to their preinjury level. All outcome scores improved from preoperatively to postoperatively: mHHS, from 68.5 ± 18.1 to 88.3 ± 18.5; NAHS, from 50.8 ± 17.7 to 69.0 ± 11.4; iHOT-12, from 36.9 ± 19.3 to 75.2 ± 19.8; VHS, from 53.8 ± 13.7 to 79.4 ± 19.4; and HOS--Sports, from 59.9 ± 17.0 to 79.6 ± 21.3 (P < .001 for all). In total, 3 patients could not return to artistic activities as the result of postoperative deep gluteal syndrome.

Conclusion:

ESA concomitant with labral repair, cam osteoplasty, and capsular plication to treat dysplastic hips in patients with joint laxity enabled artistic athletes to return to their activities with a high success rate.

Short-term patient-reported outcomes following concomitant hip arthroscopy and the endoscopic modified shelf procedure for the treatment of acetabular dysplasia and intra-articular pathology

The shelf procedure is a treatment of acetabular dysplasia, with the aim of increasing weight-bearing acetabular coverage. Although several shelf techniques have been described, the endoscopic procedure with concomitant hip arthroscopy is a new, less invasive alternative. Outcomes following this procedure are scarce. The purpose of this study was to report short-term patient-reported outcomes (PROs) following concomitant hip arthroscopy and endoscopic modified shelf procedure in the setting of acetabular dysplasia and labral tears. Patients that met extraordinarily selective surgical indications and underwent the abovementioned surgery between February 2016 and October 2019 and had minimum 1-year follow-up were included. There were five females with a mean age of 40.18 ± 5.05 years and follow-up of 21.55 ± 8.68 months. The lateral center-edge angle increased from 15.80° to 23.20° (P = 0.003), and vertical center-edge angle increased from 16.60° to 23.60° (P < 0.001). The Tönnis angle decreased from 15.40° to 3.74° (P < 0.001). The alpha angle decreased from 58.46° to 40.70° (P < 0.001). PROs demonstrated significant improvement at latest follow-up (modified Harris Hip Score, P = 0.042; Non-Arthritic Hip Score, P < 0.001; Hip Outcome Score–Sports Specific Subscale, P = 0.035; Visual Analog Scale, P < 0.001; International Hip Outcome Tool-12, P = 0.043), and satisfaction was 8.60 ± 0.89. No secondary surgeries were reported. Concomitant hip arthroscopy and endoscopic modified shelf procedure appears to be a safe and effective procedure for patients with acetabular dysplasia and labral tears yielding favorable outcomes and satisfaction at short-term follow-up.

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

PURPOSES

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

III; Case-Control study.

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.

Successful return to sport in patients with symptomatic borderline dysplasia following hip arthroscopy and T-shaped capsular plication

PURPOSE

This study aims to evaluate the return to sport and correlations of patients with symptomatic borderline hip dysplasia (BHD) after hip arthroscopy and T-shaped capsular plication at a minimum follow-up of 24 months.

METHODS

Twenty-five patients who underwent hip arthroscopy and T-shaped capsular plication for symptomatic BHD were included in the study. All the patients were evaluated clinically prior to surgery (T₀) and at two consecutive follow-ups (T₁:15 ± 1.2 months and T₂: 53.9 ± 23.2 months) using the visual analogue scale (VAS) pain score, whereas sports activity was assessed by the Hip Outcome Score Sport Specific Subscale (HOS-SSS), the University of California, Los Angeles (UCLA) activity scale, the Tegner score and the physical component (PCS) of the Short Form-12 (SF-12). Furthermore, the presence of correlations and the possible differences between subgroups were evaluated and analysed.

RESULTS

A significant difference was found for HOS-SSS, VAS, Tegner, UCLA and PCS with the Friedman test for repeated measures through time points (p < 0.0001). Moreover, all the scores reported significant improvement compared to the previous time point (p < 0.0001) except the HOS-SSS between T₁ and T₂ (n.s.). Body Mass Index (BMI) was negatively correlated with HOS-SSS at T₀ (rho = - 0.526 p = 0.006) and T₁ (rho = - 0.425; p = 0.034), with Tegner at each follow-up (T₀: rho = - 0470 p = 0.017; T₁: rho = - 0.450; p = 0.024; T₂: rho = - 0.448; p = 0.024), with UCLA at T₁ (rho = - 0.396 p = 0.049), with pre-operative PCS (rho = - 0.413 p = 0.0401), and positively correlated with pre-operative VAS (rho = 0.436 p = 0.0291).

CONCLUSIONS

Hip arthroscopy and T-shaped capsular plication in young patients with symptomatic BHD demonstrates a significant increase in return to sport and physical activity and low risk of complications. T-shaped capsular plication procedure may be considered in young and active patients for whom non-operative treatment failed and who have a significant limitation in sports activity; in these patterns of patients, the ideal treatment should reliably allow fast recovery in combination with very low invasiveness which will prevent osteoarthritis. The results of this study provide more accurate information regarding return to sport in patients with BHD after hip arthroscopy and T-shaped capsular plication.

LEVEL OF EVIDENCE

Level IV.

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.

Hip Instability in the Athlete: Anatomy, Etiology, and Management

In this review, the recent literature evaluating the anatomic considerations, etiology, and management options for athletes with hip instability are investigated. Studies on the osseous, chondrolabral capsuloligamentous, and dynamic muscular contributions to hip stability are highlighted. Microinstability, iatrogenic instability, and femoroacetabular impingement-induced instability are discussed with a focus on demographic and outcomes research in athletes. Surgical techniques including both open and arthroscopic approaches are additionally evaluated.

Periacetabular Osteotomy as a Salvage Procedure: Early Outcomes in Patients Treated for Iatrogenic Hip Instability

BACKGROUND

A periacetabular osteotomy (PAO) can reduce pain and improve quality of life in patients with hip dysplasia. While its utility for patients without traditional radiographic parameters for hip dysplasia has not been previously established, the PAO may help treat patients with hip instability that does not improve following single or multiple hip arthroscopic procedures, or when such procedures lead to hip instability.

METHODS

A single-surgeon registry of patients at a single institution was queried to identify patients with a lateral center-edge angle (LCEA) of ≥24° and a Tönnis angle of <10° who underwent PAO because of hip pain and/or instability that failed treatment with hip arthroscopy. Descriptive summary statistics were reported on patient demographics, mean change in LCEA, and patient-reported outcome measures, including the modified Harris hip score (mHHS) and the International Hip Outcome Tool-33 (iHOT-33), at a minimum of 6 months of follow-up.

RESULTS

Among 25 patients (mean age, 27.3 ± 6.9 years; 100% women), the mean LCEA increased from 27.2° (range, 24° to 37°) preoperatively to 39.0° ± 5.1° postoperatively (net increase, 11.8° ± 4.5°). Overall, the mean improvement in the mHHS was 11.5 ± 16.9 (preoperative, 59.4 ± 11.6; postoperative, 70.9 ± 20.6) and the mean improvement in the iHOT-33 was 23.8 ± 23.6 (preoperative, 32.2 ± 17.2; postoperative, 56.0 ± 30.0). Eighteen patients (72%) achieved a minimal clinically important improvement in mHHS (mean improvement, 17.4 ± 12.9) and iHOT-33 (mean improvement, 32.4 ± 19.1) scores. In comparison with 7 patients who did not show improvement, the 18 patients who showed improvement had significantly greater mean baseline patient-reported outcome scores.

CONCLUSIONS

To our knowledge, these findings provide the first report on outcomes of PAO in patients with hip pain following arthroscopy who do not meet the traditional criteria for acetabular dysplasia. Early benefits in clinical outcomes suggest a novel surgical indication for PAO as a potential salvage option for selected patients; however, longer-term studies are needed.

LEVEL OF EVIDENCE

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

Postoperative Deep Gluteal Syndrome After Hip Arthroscopic Surgery

Background

Deep gluteal syndrome (DGS) is an uncommon source of buttock and groin pain, resulting from entrapment of the sciatic nerve in the deep gluteal space. The incidence and risk factors of postoperative DGS after primary hip arthroscopic surgery are currently unknown.

Purpose

To investigate the incidence and risk factors of postoperative DGS after primary hip arthroscopic surgery.

Study Design

Case-control study; Level of evidence, 3.

Methods

This study reviewed 1167 patients who underwent arthroscopic surgery between 2010 and 2018 by a single surgeon at a single center in Japan. DGS was defined using the seated piriformis stretch test, active hamstring test, and evidence of a hypertrophic sciatic nerve on magnetic resonance imaging. Overall, 11 of 1167 patients were diagnosed with DGS postoperatively. The DGS group (n = 11) was compared with the non-DGS group (n = 1156). Patient age, sex, body mass index (BMI), generalized joint laxity (GJL; Beighton score >6), number of hip arthroscopic procedures, and radiographic parameters including lateral center-edge angle, Sharp angle, vertical center anterior angle, Tönnis angle, alpha angle, ischiofemoral distance, ischiofemoral space, and quadratus femoris space were compared. The prevalence of developmental dysplasia of the hip (DDH) and borderline DDH (BDDH) was also compared. Logistic regression analysis was conducted to identify potential predictors for a postoperative DGS diagnosis.

Results

The incidence of postoperative DGS in our study was 0.9%. Female sex (male:female ratio: 0:11 in DGS group vs 568:588 in non-DGS group; P < .01), mean number of hip surgical procedures (1.8 ± 0.9 in DGS group vs 1.1 ± 0.4 in non-DGS group; P < .01), and GJL (P < .01) were significantly higher in the DGS group, while the mean BMI was significantly lower in the DGS group (19.8 ± 1.8 vs 22.7 ± 3.6 kg/m², respectively; P < .01). Radiographic parameters were not significantly different between groups. Logistic regression analysis revealed that female sex (odds ratio [OR], 22.0 [95% CI, 1.29-374.56]), multiple surgical procedures (OR, 7.8 [95% CI, 2.36-25.95]), GJL (OR, 40.9 [95% CI, 8.74-191.70]), lower BMI (OR, 0.77 [95% CI, 0.644-0.914]), and DDH/BDDH (OR, 18.1 [95% CI, 2.30-142.10]) were potential predictors of postoperative DGS.

Conclusion

The incidence of postoperative DGS in our study was 0.9%. The predictors for postoperative DGS after hip arthroscopic surgery were female sex, GJL, multiple hip surgical procedures, and DDH/BDDH. Although hip arthroscopic surgery can provide favorable clinical outcomes, surgeons should be aware of the risk factors for DGS as a complication of hip arthroscopic surgery.

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

BACKGROUND

Arthroscopic management of femoroacetabular impingement (FAI) in the setting of borderline hip dysplasia is controversial. Recently, there has been increased awareness of a prominent anterior inferior iliac spine (AIIS) resulting in subspinous impingement.

PURPOSE/HYPOTHESIS

The purpose was to report outcomes of arthroscopic subspinous decompression in patients with symptomatic hip impingement and borderline hip dysplasia compared with a matched cohort with nondysplastic FAI. Addressing a prominent subspinous region and cam/pincer lesion in the borderline dysplastic hip may lead to favorable outcomes comparable with those of patients undergoing arthroscopic management of nondysplastic FAI.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients with symptomatic hip impingement, borderline dysplasia (lateral center-edge angle [LCEA], 18°-24°), and prominent AIIS (BDSI group) whose nonoperative management failed and who subsequently underwent arthroscopic subspinous decompression were retrospectively identified. Three-dimensional computed tomography imaging was used to categorize AIIS morphology into type 1, 2, or 3 (Hetsroni classification). Patient-reported outcome (PRO) scores consisting of the modified Harris Hip Score (mHHS), Hip Outcome Score-Activities of Daily Living (HOS-ADL), and Hip Outcome Score-Sport-Specific Subscale (HOS-SSS) were obtained preoperatively and at an average of 44 months postoperatively (range, 23-61 months). Exclusion criteria were Tönnis osteoarthritis grade >1 and a history of previous hip procedures. An age-, sex-, and body mass index-matched cohort of patients without dysplasia (LCEA, >25°) who underwent arthroscopic FAI surgery with a minimum 2-year follow-up were selected to serve as the control group.

RESULTS

Eighteen patients, 19 hips (14 women and 4 men; average age, 28 years) were included. Of the 19 hips in the BDSI group, the average LCEA and alpha angle were 21.8° and 66.2°, respectively; 14 hips were Hestroni type 2, and 5 hips were type 1. There were no postoperative complications or additional procedures performed since the last follow-up. Repeated-measures analysis of variance revealed a significant improvement in all PRO scores from preoperatively to the last follow-up: mHHS, 64.7 to 87.7 (P < .001); HOS-ADL, 62.1 to 92.1 (P < .001); HOS-SSS, 26.5 to 87.1 (P < .001). An analysis of covariance revealed that patients with type 2 AIIS had a significantly higher postoperative mHHS than those with a type 1 morphology (88.3 and 95.6, respectively; P < .01) The BDSI group had a significantly lower preoperative HOS-SSS (26.5; P < .001) in comparison with the control group. However, there was no significant difference in postoperative outcome scores between groups. The BDSI group underwent significantly more microfracture, capsular plication, and ligamentum teres debridement (15.8%; P = .04).

CONCLUSION

Arthroscopic AIIS decompression in patients with coexisting borderline dysplasia and subspinous impingement is a safe and effective method of treatment that produces outcomes comparable with those of a cohort with nondysplastic FAI.

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

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.

Approach to the Patient With Failed Hip Arthroscopy for Labral Tears and Femoroacetabular Impingement

There has been an exponential increase in the diagnosis and treatment of patients with femoroacetabular impingement, leading to a rise in the number of hip arthroscopies done annually. Despite reliable pain relief and functional improvements after hip arthroscopy in properly indicated patients, and due to these increased numbers, there is a growing number of patients who have persistent pain after surgery. The etiology of these continued symptoms is multifactorial, and clinicians must have a fundamental understanding of these causes to properly diagnose and manage these patients. Factors contributing to failure after surgery include those related to the patient, the surgeon, and the postoperative physical therapy. This review highlights common causes of failure, including those related to residual bony deformity as well as capsular deficiency, and provides a framework for diagnosis and treatment of these patients.

What Is the Impact of Periacetabular Osteotomy Surgery on Patient Function and Activity Levels?

BACKGROUND

Periacetabular osteotomy (PAO) is a hip preserving procedure performed often in younger, highly active patients. However, counseling patients is difficult, as there are limited data regarding activity level after PAO. The purpose of this study is to analyze the physical activity levels after PAO in a large, prospective multicenter cohort.

METHODS

Prospectively collected data from a multicenter study group included 359 hips treated by PAO for hip dysplasia at a mean age of 25.1 years. Patient demographics, radiographic measures, operative data, and clinical outcomes were evaluated preoperatively, at 1 year, and at minimum 2 years postoperatively. Activity level was assessed with the University of California Los Angeles (UCLA) activity score, and patients were stratified into low activity, moderate activity, and high activity groups based on preoperative function.

RESULTS

Compared to preoperative scores across the complete cohort, postoperative UCLA scores were improved on average 0.6 points at final follow-up (P = .001). The low activity and moderate activity groups had significant improvement in UCLA scores (P < .001 and P = .0007, respectively), while the high activity groups saw a significant decrease in UCLA activity scores (P < .0001). Modified Harris Hip Score, Hip Disability and Osteoarthritis Score Pain, and Hip Disability and Osteoarthritis Score Sports and Recreation scores were significantly improved across all preoperative activity levels. Multivariable linear regression (r² = 0.45) confirmed prior ipsilateral surgery as a predictor for change in UCLA score (P = .002).

CONCLUSION

Overall, these data suggest that consistent improvements in activity level and function can be expected following PAO surgery, with greater gains experienced by patients with lower preoperative levels of activity.

Outcomes of periacetabular osteotomy for borderline hip dysplasia in adolescent patients

Treatment of borderline acetabular dysplasia (lateral center edge angle ≥18°) remains controversial, and there is a paucity of literature focusing on outcomes in adolescent patients. The purpose of this study was to evaluate the outcomes of a periacetabular osteotomy (PAO) as surgical management of borderline acetabular dysplasia in adolescent patients. We performed a retrospective review of prospectively collected data and included patients ≤ 21 years of age that underwent PAO for borderline acetabular dysplasia. All patients had a minimum of 1-year follow-up. Outcomes were assessed using modified Harris Hip Scores (mHHS), Hip Outcome Scores (HOS) and international Hip Outcome Tool (iHOT-33). Descriptive and univariate statistical analyses were performed. This study included 33 adolescent patients (35 hips) with symptomatic, borderline acetabular dysplasia. The majority of patients was female (32 patients, 97%); half of all patients reported a history of hip pain for over 1 year; and seven patients had previous hip arthroscopy. In addition to PAO, seven hips (20%) underwent a concurrent hip arthroscopy at the time of surgery. There were significant improvements in mean mHHS, HOS-activities of daily living (ADL), HOS-Sport and iHOT-33 scores after surgery (P < 0.01). Minimal clinically important difference in outcome scores was achieved for over 90% of patients at a minimum of 1-year follow-up. Borderline acetabular dysplasia is a major cause of hip pain in adolescent patients. Patients with symptomatic borderline acetabular dysplasia report a significant benefit after a PAO to correct structural hip instability.

Clinical and radiographic predictors of failed hip arthroscopy in the management of dysplasia: a systematic review and proposal for classification

PURPOSE

As indications for hip arthroscopy continue to expand, its efficacy in patients with more complex deformities of the hip, such as those with acetabular dysplasia, remains controversial. The purpose of this systematic review is to identify the predictors of failed hip arthroscopy in dysplastic hips and to propose a standardize prognostic sub-classification of dysplasia.

METHODS

This systematic review was performed in accordance with the (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) PRISMA guidelines. Three databases [EMBASE, PubMed, and Ovid (MEDLINE)] were searched using terms including "hip arthroscopy" and "dysplasia". Studies were screened and data extracted in duplicate. Study quality was assessed using the Methodological Index for Non-Randomized Studies criteria. Due to the non-uniform nature of study data, findings were presented in descriptive summary form.

RESULTS

Thirteen studies were included in this systematic review, comprising 712 dysplastic patients (773 hips) with mean age 34.2 years and 74.1% females. Most studies defined hip dysplasia by a lateral centre-edge angle (LCEA) of 20°-25° (borderline) or 15°-20° (moderate). Failure was defined as progression to revision arthroscopy, peri-acetabular osteotomy, or total hip arthroplasty. Overall, failure rate was 192/743 (25.8%) at an average of 28.1 months following index arthroscopy. Smaller LCEA, larger Tönnis angle, broken Shenton line, and decreased joint space (≤ 2 mm) were radiographic predictors of failure. Severe cartilage lesions to the femoral head or acetabulum were associated with failure in five studies. Labral debridement led to more failures than labral repair.

CONCLUSION

Overall, hip arthroscopy yielded good outcomes in mildly dysplastic hips without severe chondral damage. Hip arthroscopy is expected to result in a failed outcome in individuals with moderate-to-severe hip dysplasia (LCEA < 15°), severe cartilage lesions, larger Tönnis angle (> 20°), broken Shenton line, and decreased joint space (≤ 2 mm). Arthroscopic surgery may be more effective in individuals with borderline-to-mild (LCEA 15°-25°) acetabular dysplasia in the absence of severe cartilaginous lesions (7-year survival: 89.6%). A standardized prognostic classification of hip dysplasia based on the LCEA and Tönnis angle is proposed.

LEVEL OF EVIDENCE

Systematic review of non-randomized studies, Level IV.

Surgical Outcomes in the Treatment of Concomitant Mild Acetabular Dysplasia and Femoroacetabular Impingement: A Systematic Review

PURPOSE

To analyze the current approaches and clinical outcomes in the surgical management of concomitant mild acetabular dysplasia and femoroacetabular impingement (FAI).

METHODS

Following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) method, the PubMed and Medline databases were searched in March 2019 for studies that reported on surgical outcomes in hips with concomitant mid acetabular dysplasia and FAI. Studies published in English that focused on the surgical outcomes after hip arthroscopy, open surgery, or periacetabular osteotomy of concomitant acetabular dysplasia and FAI, in which the lateral center-edge angle of all subjects was between 15° and 25°, were included. Articles that included subjects with lateral center-edge angle <15°, with a minimum follow-up duration <1 year, had <5 subjects, or were not original articles were excluded.

RESULTS

The initial search yielded 748 studies, and 5 studies met the inclusion criteria. All these 5 studies focused on hip arthroscopic treatment for patients with concomitant mild acetabular dysplasia and FAI. Three studies had level III evidence, whereas 2 studies had level IV evidence. The mean patient age range across the studies was 29.8 to 49.6 years, and the female-to-male ratio was 1.14. Improved patient-reported outcomes (Hip Outcome Score-Activities of Daily Living, Hip Outcome Score-Sport, modified Harris Hip Score, Short Form-12 Physical Component Summary, Western Ontario and McMaster Universities Osteoarthritis Index) at a minimum 2-year follow-up were obtained in 4 of the 5 studies. Two of these 4 studies had a comparative cohort of patients with FAI with normal acetabular coverage, and there was no significant difference in the postoperative outcomes and secondary procedure rate between patients with mild acetabular dysplasia and those with normal acetabular coverage.

CONCLUSIONS

This systematic review indicates that improved patient-reported outcomes can be obtained with hip arthroscopy in the treatment of concomitant mild acetabular dysplasia and FAI at a minimum 2-year follow-up.

LEVEL OF EVIDENCE

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

An Intact Ligamentum Teres Predicts a Superior Prognosis in Patients With Borderline Dysplasia: A Matched-Pair Controlled Study With Minimum 5-Year Outcomes After Hip Arthroscopic Surgery

BACKGROUND

Hip arthroscopic surgery in patients with borderline dysplasia continues to be controversial. In addition, it has been suggested that ligamentum teres (LT) tears may lead to inferior short-term patient-reported outcomes (PROs) when compared with a match-controlled group.

PURPOSES

(1) To report minimum 5-year PROs in patients with borderline dysplasia and LT tears who underwent hip arthroscopic surgery and (2) to compare these PROs to those of a matched-pair control group of patients with borderline dysplastic hips without LT tears.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Data were prospectively collected for patients who underwent hip arthroscopic surgery between September 2008 and August 2013. Patients were included if they had a preoperative diagnosis of borderline dysplasia (lateral center-edge angle [LCEA], 18°-25°) and had preoperative and minimum 5-year postoperative modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), and visual analog scale (VAS) for pain scores. Exclusion criteria were osteoarthritis of Tönnis grade >1, previous hip conditions, any previous ipsilateral hip surgery, or workers' compensation status. There were 2 borderline dysplastic groups created. An LT tear group was matched 1:1 to a control group (no LT tear) with similar age, sex, body mass index (BMI), and laterality via propensity score matching. Significance was set at P < .05.

RESULTS

A total of 24 patients with an LT tear (24 hips) were matched to 24 patients without an LT tear (24 hips). There was no significant difference in age, sex, BMI, or laterality between groups. The mean age was 36.2 ± 17.2 and 34.9 ± 15.9 years for the control and LT tear groups, respectively (P = .783). There were 17 (70.8%) and 16 (66.7%) female patients in the control and LT tear groups, respectively, and the mean preoperative LCEA was 23.3° and 22.2° in the control and LT tear groups, respectively. No differences were observed between groups in baseline PROs, intraoperative findings, or surgical procedures. LT debridement was performed in 17 (70.8%) patients in the LT tear group compared with 0 (0.0%) in the control group. Also, 5-year postoperative PROs were comparable in both groups, with the control group exhibiting superior Veterans RAND 12-Item Health Survey (VR-12) mental (P = .041) and Short Form-12 (SF-12) mental (P = .042) scores. Finally, hips with an intact LT were significantly more likely (P = .022) to achieve the patient acceptable symptomatic state (PASS) for the mHHS (100.0% and 75.0%, respectively). No significant differences were present between the groups for the minimal clinically important difference (MCID) of the mHHS (P = .140), MCID of the Hip Outcome Score-Sport-Specific Subscale (HOS-SSS) (P = .550), or PASS of the HOS-SSS (P = .390).

CONCLUSION

After hip arthroscopic surgery, patients with borderline dysplasia and LT tears demonstrated favorable PROs at a minimum 5-year follow-up. Outcomes were similar to a matched-pair control group without LT tears, with the group with intact LTs showing higher VR-12 mental and SF-12 mental scores. Furthermore, patients with borderline dysplasia and intact LTs were significantly more likely to achieve the PASS for the mHHS.

Acetabular Morphologic Characteristics Predict Early Conversion to Arthroplasty After Isolated Hip Arthroscopy for Femoroacetabular Impingement

BACKGROUND

Hip arthroscopy in the setting of dysplasia and borderline dysplasia is controversial. Dysplasia severity is most often defined by the lateral center edge angle (LCEA) but can also be evaluated radiographically by the acetabular inclination (AI).

PURPOSE/HYPOTHESIS

The purpose was to determine the effect of AI on outcomes after isolated hip arthroscopy for femoroacetabular impingement (FAI). We hypothesized that patients with dysplasia would have higher rates of arthroplasty as well as inferior clinical and functional outcomes compared with patients who did not have dysplasia.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A hip arthroscopy registry was reviewed for participants undergoing arthroscopic correction of FAI from February 28, 2008, to June 10, 2013. Participants required a clinical diagnosis and isolated arthroscopic correction of FAI with preoperative imaging and intraoperative cartilage status recorded. AI dysplasia was defined as an AI greater than 10°, LCEA dysplasia as LCEA less than 18°, and borderline LCEA dysplasia as LCEA 18° to 25°. Patients without an acetabular deformity (LCEA 25°-40°; AI <10°) served as a control population. Postoperative variables included patient-reported outcome surveys with conversion to arthroplasty as the primary endpoint. Minimum 5-year outcome scores were obtained for 337 of 419 patients (80.4%) with an average follow-up of 75.2 ± 12.7 months.

RESULTS

This study included 419 patients: 9 (2%) with LCEA dysplasia, 42 (10%) with AI dysplasia, and 51 (12%) with borderline dysplasia. The AI but not LCEA was significantly correlated with lower outcome scores on the modified Harris Hip Score (r = 0.13; P = .01), Non-Arthritic Hip Score (r = 0.10; P = .04), and Hip Outcome Score-Sports Subscale (r = 0.11; P = .04). A total of 58 patients (14%) underwent arthroplasty at 31 ± 20 months postoperatively. Patients with LCEA dysplasia had an arthroplasty rate of 56% (odds ratio, 8.4), whereas patients with AI dysplasia had an arthroplasty rate of 31% (odds ratio, 3.3), which was significantly greater than the rate for the nondysplastic cohort (13.5%; P < .0001). Patients with borderline LCEA dysplasia did not have increased rates of arthroplasty. A multivariate analysis found increasing age, increasing AI, Tönnis grade higher than 1, and femoral Outerbridge grade higher than 2 to be most predictive of conversion to arthroplasty.

CONCLUSION

We found that an elevated AI, along with increasing age, Tönnis grade, and femoral Outerbridge grade significantly predict early conversion to arthroplasty after isolated hip arthroscopy. We recommend using the AI, in addition to the LCEA, in evaluating hip dysplasia before hip arthroscopy.

Postoperative Weightbearing Protocols After Arthroscopic Surgery for Femoroacetabular Impingement Does Not Affect Patient Outcome: A Comparative Study With Minimum 2-Year Follow-up

PURPOSE

To evaluate the effects of immediate postoperative weightbearing protocols after hip arthroscopy for femoroacetabular impingement (FAI) with minimum 2-year follow-up, as measured by patient-reported outcome measures and satisfaction rates.

METHODS

Between January 2011 and June 2016, patients undergoing hip arthroscopy for FAI and labral tears were reviewed. Exclusion criteria was previous hip pathology or arthroscopy, active Workers' Compensation claims, and concomitant pathologies impeding weightbearing. Patients who were operated on before September 2013 were treated with 3 weeks of postoperative non-weightbearing (NWB), with weightbearing as tolerated (WBAT) thereafter. From October 2013, patients were allowed immediate postoperative WBAT.

RESULTS

A total of 351 hip arthroscopic surgeries were performed; 133 of these patients met the inclusion criteria. Of the 133 included patients, 69 were in the NWB group and 64 were in the WBAT group. No differences were found in terms of sex (P = .603) or age (P = .241). No differences were found in postoperative scores (the Modified Harris Hip Score was 84.5 [range 79-89] for NWB vs 86.7 [78-89] for WBAT [P = .0.523], and the Hip Outcome Score was 83.1 [78-88] vs 88.4 [80-90], respectively; P = .130). Subjective rates of improvement, satisfaction score and the will to undergo surgery again did not differ between the groups (P = .674, P = .882, P = .730). The rate of subjects who met or exceeded the MCID in the NWB and WBAT groups was 82.6% and 81.2% for the Modified Harris Hip Score (P = .838) and 79.7% and 82.8% for the Hip Outcome Score (P = .647). There were no reported complications. Limitations include the possibility of the study being underpowered.

CONCLUSIONS

After a 2-year minimum follow-up, patient-reported outcome measures and satisfactory rates with immediate weightbearing after hip arthroscopy for isolated FAI syndrome and labral tears do not differ significantly from results after strict NWB rehabilitation protocols. Revising weightbearing restrictions may allow for a more comfortable rehabilitation process after arthroscopic hip surgery for FAI and labral repair.

LEVEL OF EVIDENCE

Level 3 - case-control study.

Is the Femoro-Epiphyseal Acetabular Roof (FEAR) index on MRI a relevant predictive factor of instability in a borderline dysplastic hip?

AIMS

A borderline dysplastic hip can behave as either stable or unstable and this makes surgical decision making challenging. While an unstable hip may be best treated by acetabular reorientation, stable hips can be treated arthroscopically. Several imaging parameters can help to identify the appropriate treatment, including the Femoro-Epiphyseal Acetabular Roof (FEAR) index, measured on plain radiographs. The aim of this study was to assess the reliability and the sensitivity of FEAR index on MRI compared with its radiological measurement.

PATIENTS AND METHODS

The technique of measuring the FEAR index on MRI was defined and its reliability validated. A retrospective study assessed three groups of 20 patients: an unstable group of 'borderline dysplastic hips' with lateral centre edge angle (LCEA) less than 25° treated successfully by periacetabular osteotomy; a stable group of 'borderline dysplastic hips' with LCEA less than 25° treated successfully by impingement surgery; and an asymptomatic control group with LCEA between 25° and 35°. The following measurements were performed on both standardized radiographs and on MRI: LCEA, acetabular index, femoral anteversion, and FEAR index.

RESULTS

The FEAR index showed excellent intraobserver and interobserver reliability on both MRI and radiographs. The FEAR index was more reliable on radiographs than on MRI. The FEAR index on MRI was lower in the stable borderline group (mean -4.2° (sd 9.1°)) compared with the unstable borderline group (mean 7.9° (sd 6.8°)). With a FEAR index cut-off value of 2°, 90% of patients were correctly identified as stable or unstable using the radiological FEAR index, compared with 82.5% using the FEAR index on MRI. The FEAR index was a better predictor of instability on plain radiographs than on MRI.

CONCLUSION

The FEAR index measured on MRI is less reliable and less sensitive than the FEAR index measured on radiographs. The cut-off value of 2° for radiological FEAR index predicted hip stability with 90% probability. Cite this article: Bone Joint J 2019;101-B:1578-1584.

Arthroscopic Femoral Osteochondroplasty With Capsular Plication for Osteochondroma of the Femoral Neck

Osteochondromas of the femoral neck are a rare but challenging problem because of their distal location, which is difficult to access arthroscopically. Traditional methods of osteochondroma resection used invasive open approaches to manage these lesions. More recently, advances in hip arthroscopy have allowed expanded treatment of extra-articular hip conditions with a minimally invasive approach. Reports have described the use of hip arthroscopy for osteochondroma removal; however, surgical techniques for the procedure have yet to be described. We describe a technique for arthroscopic resection of a femoral neck osteochondroma using an extended capsulotomy and osteochondroplasty with subsequent capsular plication. This technique uses contemporary hip arthroscopic techniques and constitutes a safe and effective approach to addressing this rare intra-articular pathology of the hip.

Hip Arthroscopic Surgery in Borderline Developmental Dysplastic Hips: A Systematic Review

BACKGROUND

It remains controversial whether hip arthroscopic surgery should be applied to patients with a borderline developmental dysplastic hip (BDDH).

PURPOSE

To review the outcomes of hip arthroscopic surgery for a BDDH and which factors influence these outcomes.

STUDY DESIGN

Systematic review.

METHODS

PubMed, Embase, and the Cochrane Library were searched through March 2018 for studies reporting the outcomes of primary hip arthroscopic surgery in patients with a BDDH. Inclusion in the review was based on the definition of a BDDH, patient-reported outcomes, and duration of follow-up. The primary outcome was the modified Harris Hip Score (mHHS). The failure rate, visual analog scale, satisfaction score, and patient-reported outcomes such as the Hip disability and Osteoarthritis Outcome Score were defined as secondary outcomes.

RESULTS

Nine studies with 425 patients who underwent hip arthroscopic surgery were included in this review. The mean follow-up times ranged from 25.4 to 28.8 months across the studies. A significant improvement was obtained in the mHHS, with a mean score of 61.8 preoperatively to 82.8 postoperatively; all other patient-reported outcomes also improved significantly, except the 12-Item Short Form Health Survey mental component summary. The overall failure rate was 14.1%, and the mean reoperation rate was 8.5%. The rate of conversion to total hip arthroplasty ranged from 4.4% to 26.0%, and the rate of conversion to periacetabular osteotomy was 4.0%. Combined defects such as cartilage damage, hip osteoarthritis, ligamentum teres tears, and femoroacetabular impingement could influence the outcomes after arthroscopic surgery in BDDHs.

CONCLUSION

Hip arthroscopic surgery was demonstrated to be a promising approach for BDDHs, but the outcomes could be influenced by multiple risk factors. A higher level of evidence is still needed to support current findings.

The Pattern of Acetabular Cartilage Wear Is Hip Morphology-dependent and Patient Demographic-dependent

BACKGROUND

Acetabular cartilage damage has been described in patients with femoroacetabular impingement (FAI). However, most reports of articular cartilage damage in hip FAI have been focused on the acetabular cartilage and derived from single-center, retrospective studies of relatively small patient cohorts. Identifying patterns of articular cartilage wear is important in patient selection, treatment prognosis, and determining whether patterns of intraarticular cartilage wear are secondary to abnormal hip morphology. Using a multicenter, observational cohort, we sought to determine whether there was a specific pattern of cartilage wear across acetabular and femoral articular cartilage among patients with symptomatic FAI.

QUESTIONS/PURPOSES

(1) Is there is a specific pattern of cartilage wear in the acetabulum and femoral head, assessed during hip arthroscopy, in cam FAI, pincer, and mixed-type hip pathologies? (2) Are there specific patterns of cartilage wear associated with duration of symptoms, age, and/or body mass index (BMI)?

METHODS

A multicenter observational cohort and a hip preservation database from a senior author were used to identify 802 patients who underwent hip arthroscopy for the treatment of symptomatic FAI. The diagnosis of cam, pincer, or mixed-type FAI was determined by each treating surgeon at each institution using the minimum basic criteria of pain in the affected hip for a period of > 3 months, hip ROM, and radiographic findings. Acetabular and femoral head cartilage lesions were classified arthroscopically by location and severity for each group (cam, pincer, or mixed FAI). Cartilage wear was classified using the Beck classification and defined as cartilage lesions greater than Grade 1 (normal macroscopically sound cartilage). The assessment of cartilage wear was performed arthroscopically by experienced hip preservation surgeons who are a part of ANCHOR, a multicenter group that uses a longitudinally maintained database to investigate issues related to hip preservation surgery. Clinical characteristics, radiographic findings, and acetabular and femoral head damage by location and severity of wear were reported based on patient diagnoses of cam (n = 472), mixed (n = 290), and pincer (n = 40) FAI hip pathologies. Wald chi-square tests were used to test for differences in the presence of wear in each cartilage quadrant across hip pathologies, duration of symptoms, age, and BMI. One-way analysis of variance tests were used to test for differences in average grade of wear in each cartilage quadrant across hip pathologies, duration of symptoms, age, and BMI. A bivariate logistic regression model was used to identify factors independently associated with the presence of cartilage wear in the acetabulum and femoral head. Acetabular cartilage wear was present in 743 of 802 patients (93%) in the cohort. Femoral head cartilage wear was observed in only 130 (16%).

RESULTS

We found significant associations between acetabular patterns of wear and FAI hip pathologies; specifically, we observed more frequent and severe debonding of acetabular cartilage in patients with symptomatic cam (93%, 1.7 ± 1.1 grade) and mixed (97%, 1.7 ± 1.2 grade) FAI compared with Pincer (75%, 1.5 ± 0.9 grade) FAI hip pathologies (p < 0.001). Superolateral peripheral cartilage lesions occurred more frequently and with greater severity in patients with cam (90% [416 of 472] prevalence, 3.1 ± 1.1 grade) and mixed (91% [260 of 290] prevalence, 3.1 ± 1.1 grade) FAI than in pincer (60% [24 of 40] prevalence, 2.2 ± 1.1 grade) FAI hip pathologies (p < 0.0001). Conversely, patients with pincer FAI most commonly demonstrated cartilage lesions with an even distribution at the anterior and superolateral acetabular rim: 64% (25 of 40) (mean grade 2.1 ± 1.0) and 60% (24 of 40) mean grade 2.2 ± 1.1, respectively. Age was associated with increased presence of wear in both the acetabulum (odds ratio [OR], 1.05; 95% confidence interval [CI], 1.2-1.7; p = 0.005) and femoral head (OR, 1.08; 95% CI, 1.6-1.1; p < 0.001). BMI was associated with a greater presence of wear only in the femoral head (OR, 1.1; 95% CI, 1.2-1.1; p = 0.002). Specifically, compared with patients with a BMI < 30 kg/m, patients with a BMI ≥ 30 kg/m presented with more frequent and more severe lesions in the posterior peripheral acetabular rim (42% [47 of 117] versus 26% [171 of 677], p = 0.0006; grade 1.9 ± 1.3 versus grade 1.4 ± 0.9, p < 0.001), the anterolateral femoral head (22% [20 of 117] versus 9% [60 of 67], p = 0.006), and the anteromedial femoral head (15% [16 of 117] versus 6% [39 of 677], p = 0.002; grade 1.3 ± 0.8 versus grade 1.1 ± 0.6, p = 0.04). In general, we found that older patients (≥ 50 years old) presented with more frequent and more severe lesions in both the acetabulum and femoral head. We found no association between hip pathology and cartilage wear patterns in the examined femoral heads.

CONCLUSIONS

Hip morphology affects the pattern of acetabular cartilage wear. More frequent and severe cartilage lesions were observed in patients with symptomatic FAI cam and mixed-type hip pathologies. Surgical attempts to restore normal anatomy to avoid FAI should be performed to potentially improve long-term joint homeostasis. Increasing age is an independent risk for cartilage wear in both the acetabulum and femoral head. Additionally, increased BMI is an independent risk factor for cartilage wear in the femoral head. In the future, prospective studies should provide further insight into the pathomechanics of early degenerative changes associated with hip FAI deformities.

LEVEL OF EVIDENCE

Level III, prognostic study.

Trajectory of clinical outcomes following hip arthroscopy in female subgroup populations

To describe the recovery trajectory in a group of relatively older borderline dysplastic female femoroacetabular impingement syndrome (FAIS) patients following arthroscopic surgery, to determine if outcomes in this group differs from females with different age and bony morphology characteristics. Four subgroups were created to define (i) older females (>35 years), borderline dysplastic (lateral center edge angle [LCEA] ≤ 25 degrees) and anterior wall index (AWI) deficient (AWI ≤ 0.40) (older, borderline dysplastic, anterior wall deficient [ODD, reference]); (ii) younger (≤35 years), borderline dysplastic (LCEA ≤ 25 degrees) and deficient anterior wall (AWI ≤ 0.40) (younger, borderline dysplastic, anterior wall deficient [YDD]); (iii) older (>35 years), non-dysplastic (LCEA > 25 degrees) and non-deficient anterior wall (AWI > 0.40) (older, non-dysplastic, non-deficient anterior wall [ONN]); and (iv) younger (≤35 years), non-dysplastic (LCEA > 25 degrees) and non-deficient anterior wall (AWI > 0.40) (younger, non-dysplastic, non-deficient anterior wall [YNN]). One hundred and seventy-three female patients were included. Comparing mean scores, the ODD group reported significantly lower International Hip Outcome Tool (iHOT-12) change scores compared with the ONN group [23.58 ± 9.73; P = 0.03] at 12 months. ODD group also demonstrated significantly lower iHOT-12 change scores compared with the ONN (27.62 ± 8.22; P < 0.01) and YNN (25.39 ± 7.68; P < 0.01) groups at 24 months. Relatively older females with borderline dysplasia and anterior acetabular wall deficiencies had poorer iHOT-12 outcomes at both 12 and 24 months post-operatively compared with other female subgroups. In the absence of hip dysplasia and anterior wall deficiencies, superior iHOT-12 outcomes were observed in both older and younger females post-operatively.

Ptosis of the hip: a new radiographic finding in patients undergoing femoroacetabular osteoplasty

Ptosis is a newly described phenomenon appearing on AP radiographs of patients undergoing femoroacetabular osteoplasty (FAO), and refers to a reverse break down in Shenton’s Line. Thorough characterization of this phenomenon is needed to better understand the hip morphology and pathologic ramifications. Our goal was to define the radiographic hip parameters accompanying a break down in Shenton’s Line and to determine how these values compare with standard values in normal hips. Using two independent readers, we retrospectively reviewed the medical records and preoperative supine radiographs of 630 patients (1260 hips) who underwent FAO by a single surgeon between 2003 and 2016. Prevalence of hip pathology and 28 radiographic parameters in ptosis hips was measured, as well as a comparison between unilateral ptosis hips and contralateral normal hips. Of the 53 patients (106 hips) who fulfilled the criteria for the study, 94 hips had a Shenton’s Line break down of at least 5 mm. Sixty-nine percent of ptosis hips had femoroacetabular impingement (FAI), 70.2% had coxa profunda, and 52.1% had partial joint space narrowing. Ptosis hips had 1.05 mm less lateral subluxation (P = 0.012), 2.28° larger Center-edge angle (P = 0.046), 2.59° smaller Sharp angle (P = 0.011) and 2.49% smaller extrusion index (P = 0.016) compared with contralateral normal hips. FAI is prevalent in patients with a positive ptosis sign. The high prevalence of partial joint space narrowing could suggest eventual osteoarthritis. We believe our results demonstrate the importance of further investigation of a positive ptosis sign on AP pelvic radiographs.

Mild or Borderline Hip Dysplasia: Are We Characterizing Hips With a Lateral Center-Edge Angle Between 18° and 25° Appropriately?

BACKGROUND

Controversy surrounds the classification and treatment of hips with a lateral center-edge angle (LCEA) between 18° and 25°. It remains undetermined as to whether periacetabular osteotomy (PAO) or arthroscopic surgery is best used to treat this patient population.

HYPOTHESIS

Patients with hip pain and mild or borderline acetabular dysplasia defined by an LCEA between 18° and 25° have different features of acetabular and femoral morphology, as determined by other relevant radiographic measures assessing the anterior and posterior acetabular walls, anterior coverage of the femoral head by the acetabulum, and femoral head and neck junction sphericity.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A retrospective review of patients who had an LCEA between 18° and 25° undergoing hip preservation between January 2010 and December 2015 with either PAO or hip arthroscopic surgery was performed. Anteroposterior, Dunn lateral, and false profile radiographs were used to measure the LCEA, Tönnis angle, anterior center-edge angle (ACEA), anterior wall index (AWI) and posterior wall index (PWI), femoral epiphyseal acetabular roof (FEAR) index and posterior to anterior wall index, and alpha angle and femoral neck-shaft angle. An agglomerative hierarchical clustering analysis was then performed on the continuous radiographic variables to identify different subtypes of hip pathomorphology among the study cohort. There were sex-specific trends in hip morphology. Therefore, we proceeded to perform separate cluster analyses for each sex. Multivariate logistic regression was used to identify radiographic parameters for distinguishing between female patients who underwent hip arthroscopic surgery versus PAO.

RESULTS

Ninety-eight patients with hip pain and an LCEA between 18° and 25° underwent surgery in the study period, 77 (78%) were female, and 81 (82%) had complete radiographs for cluster analyses. The mean age was 22.6 years. Hip arthroscopic surgery was performed in 40 (41%) patients, and PAO was performed in 58 (59%) patients. The ACEA (45%), FEAR index (34%), and AWI (30%) were the most commonly abnormal radiographic parameters among all patients. In female patients, the ACEA (55%), FEAR index (42%), and AWI (34%) were the most commonly abnormal radiographic parameters. In male patients, the PWI (48%) was the most common radiographic abnormality. For female patients, 3 clusters representing different patterns of hip morphology were identified: acetabular deficiency with cam morphology, lateral acetabular deficiency, and anterolateral acetabular deficiency. For male patients, 3 clusters were also identified: posterolateral acetabular deficiency with global cam morphology, posterolateral acetabular deficiency with focal cam morphology, and lateral acetabular deficiency without cam morphology. The ACEA (odds ratio [OR], 47.7 [95% CI, 9.6-237.6]; P < .001) and AWI (OR, 3.9 [95% CI, 1.0-15.0]; P = .049) were identified as independent factors predicting which procedure was performed in female patients.

CONCLUSION

A comprehensive evaluation of radiographic parameters in patients with an LCEA between 18° and 25° identified sex-specific trends in hip morphology and showed a large proportion of dysplastic features among these patients. An isolated assessment of the LCEA is an oversimplistic approach that may jeopardize appropriate classification and may provide insufficient data to guide the treatment of hips with additional features of dysplasia and instability.

Is Hip Arthroscopy Effective in Patients With Combined Excessive Femoral Anteversion and Borderline Dysplasia? A Match-Controlled Study

BACKGROUND

Appropriate patient selection is critical when hip arthroscopy is considered in the setting of borderline dysplasia (BD). It is presumable that excessive femoral anteversion (EFA) and BD may contraindicate arthroscopy.

HYPOTHESIS

Patients with combined EFA and BD (EFABD) demonstrate significantly inferior short-term outcomes after arthroscopic labral preservation and capsular closure when compared with a similar control group with normal lateral coverage and femoral anteversion.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Data were prospectively collected and retrospectively reviewed on patients undergoing hip arthroscopy between April 2010 and November 2014. The EFABD group's inclusion criteria were BD (lateral center-edge angle, 18°-25°), labral tear, capsular closure, and femoral version ≥20°, as well as preoperative modified Harris Hip Score, Nonarthritic Hip Score, Hip Outcome Score-Sports Specific Subscale, and visual analog scale. Exclusion criteria were workers' compensation, preoperative Tönnis grade >1, microfracture, abductor pathology, or previous ipsilateral hip surgery or conditions. Patients in the EFABD group were matched 1:2 to a similar control group with normal coverage and femoral anteversion by age at surgery ± 6 years, sex, body mass index ± 5, acetabular Outerbridge grade (0, 1 vs 2, 3, 4), and iliopsoas fractional lengthening.

RESULTS

Sixteen EFABD cases were eligible for inclusion, and 100% follow-up was obtained at ≥2 years postoperatively. Twelve EFABD cases were matched to 24 control cases. Mean femoral version was 22.4° in the EFABD group and 10.2° in the control group ( P = .01). Mean lateral center-edge angle was 22.1° in the EFABD group and 31.5° in the control group ( P < .0001). Acetabuloplasty was performed significantly more frequently in the control group ( P = .0006). No other significant differences were found regarding demographics, findings, procedures, or preoperative scores. At latest follow-up, the EFABD group demonstrated significantly lower mean modified Harris Hip Score (76.1 vs 85.9; P = .005), Nonarthritic Hip Score (74.8 vs 88.5; P < .0001), Hip Outcome Score-Sports Specific Subscale (58.3 vs 78.4; P = .02), and patient satisfaction (7.1 vs 8.3; P = .005). There were 4 secondary surgical procedures (33.3%) in the EFABD group and 1 (4.2%) in the control group ( P = .03). One patient in each group required arthroplasty.

CONCLUSION

Patients treated with arthroscopic labral preservation and capsular closure in the setting of EFABD demonstrated significant improvements from presurgery to latest follow-up. However, their results are significantly inferior when compared with a matched-controlled group. Consideration of periacetabular osteotomy or femoral osteotomy may be warranted in the setting of EFABD to achieve optimal benefit.

The Utility of Hip Arthroscopy in the Setting of Acetabular Dysplasia: A Systematic Review

PURPOSE

To compare patient-reported outcomes, progression of osteoarthritis, and conversion to total hip replacement in a dysplastic population when hip arthroscopy was used as an isolated treatment or as an adjunct to pelvic reorientation osteotomy.

METHODS

An exhaustive search of the existing literature was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Three databases (PubMed, CINAHL [Cumulative Index to Nursing and Allied Health Literature], Embase) were searched for studies from January 1930 through January 2018 published in the English language concerning the use of hip arthroscopy with diagnostic and therapeutic intentions in individuals with acetabular dysplasia. We excluded studies that presented ambiguous data sets or in which clear identification of the strategy for arthroscopy was absent.

RESULTS

The selection criteria were defined, and 33 studies (1,368 hip arthroscopies) were included in the final analysis. Studies that met the inclusion criteria were classified within 5 different categories: (1) hip arthroscopy for screening, chondral mapping, and planning (9 studies, 729 hip arthroscopies); (2) isolated arthroscopic treatment (13 studies, 434 hip arthroscopies); (3) outcomes of hip arthroscopy after previous reorientation pelvic osteotomy for acetabular dysplasia (4 studies, 52 hip arthroscopies); (4) arthroscopy followed by unplanned hip-preservation surgery (3 studies, 48 hip arthroscopies); and (5) combined arthroscopy and periacetabular osteotomy (4 studies, 106 hip arthroscopies). A risk-of-bias analysis showed a moderate to high risk of bias (level 3 or 4) within and across the included studies.

CONCLUSIONS

Although hip arthroscopy can be used to accurately grade the severity of chondral injuries in the native hip and provide zone-specific geographic mapping that may aid in subsequent surgical planning, there is insufficient evidence to conclude that arthroscopic characterization alone has any bearing on the ultimate clinical outcomes after osseous structural correction. Isolated arthroscopic treatment is not recommended in the setting of moderate to severe dysplasia, given the inferior clinical outcomes and risk of iatrogenic instability reported for this group. However, there is limited evidence to suggest that the isolated use of hip arthroscopy may be considered in cases of borderline acetabular dysplasia when careful attention is paid to labral and capsular preservation. Limited evidence supports the conclusion that after prior reorientation pelvic osteotomy for acetabular dysplasia, hip arthroscopy leads to improved clinical and functional outcomes and should be considered in this setting. Furthermore, there is insufficient evidence to conclude that failed hip arthroscopy compromises or challenges the ultimate clinical outcomes in patients undergoing subsequent reorientation pelvic osteotomy. Last, there is insufficient evidence to conclude that the adjunctive use of hip arthroscopy with reorientation pelvic osteotomy produces superior clinical outcomes compared with pelvic osteotomy alone. In summary, arthroscopic techniques may provide a useful complement to the correction of acetabular dysplasia and should be thoughtfully considered on a case-by-case basis when designing a comprehensive treatment strategy in dysplastic populations.

LEVEL OF EVIDENCE

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

Arthroscopic Capsular Plication in Patients With Labral Tears and Borderline Dysplasia of the Hip: Analysis of Risk Factors for Failure

BACKGROUND

Hip arthroscopy for the treatment of instability in the setting of borderline dysplasia is controversial. Capsular management in such cases is an important consideration, and plication has been described as a reliable technique, with good midterm outcomes reported when indications are appropriate.

HYPOTHESIS

Patients with borderline dysplasia who have a lower lateral center-edge angle (LCEA) and greater age will be at a higher risk of failure after arthroscopic capsular plication.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Data were retrospectively reviewed for all patients between 15 and 40 years of age who underwent hip arthroscopy from November 2008 to January 2015. Inclusion criteria were an LCEA between 18° and 25°, Tönnis grade ≤1, primary case with capsular plication, and minimum 2-year follow-up. Patients were excluded if they had any history of ipsilateral hip procedure or conditions such as Legg-Calve-Perthes disease, slipped capital femoral epiphysis, rheumatologic disease, and Tönnis grade ≥2. Age, sex, and body mass index data were retrieved for each patient. Patient-reported outcomes (PROs)-including modified Harris Hip Score (mHHS), Non-Arthritic Hip Score (NAHS), Hip Outcome Score-Sports Specific Subscale, and a visual analog scale (VAS) for pain (0-10)-were obtained preoperatively and at a minimum of 2 years postoperatively, in addition to the postoperative International Hip Outcome Tool-12. The "success" group consisted of all patients who achieved the patient acceptable symptomatic state of mHHS ≥74 and had no ipsilateral hip surgery subsequent to their index arthroscopy. The "failure" group was composed of patients who were below the patient acceptable symptomatic state at latest follow-up or required secondary arthroscopy or conversion to total hip arthroplasty. Patient satisfaction and minimal clinically important difference were also calculated. Mean age for the failure group was applied as a cutoff age for subanalysis, and relative risk for failure was determined.

RESULTS

Ninety patients (97 hips; 79.5%) met criteria for the success group, and 25 patients (25 hips) met criteria for the failure group. No significant differences in preoperative baseline scores or VAS were found. However, there did appear to be a trend that the failure group had lower mean preoperative scores for all PRO measures and a higher VAS score. The differences in preoperative mHHS and NAHS closely approached significance ( P = .053). Postoperative PRO, VAS, and patient satisfaction scores of the success group were significantly higher than the failure group. The failure group was significantly older than the success group (28.5 ± 7.8 vs 23.5 ± 7.5 years, P = .005). Patients >35 years old were 2.25 times more likely to fail according to relative risk (95% CI, 1.10-4.60; P = .0266). LCEA did not differ between the groups, and no other risk factors for failure were identified.

CONCLUSION

Stringent criteria for patient selection and meticulous repair or augmentation of the static stabilizers of the hip yielded favorable clinical outcomes in this study cohort with borderline dysplasia. Within this carefully selected group, the analysis revealed that increased age was the main risk factor for failure in the management of borderline hip dysplasia via isolated primary arthroscopic hip surgery with capsular plication.

Clinical and Radiographic Predictors of Acetabular Cartilage Lesions in Adolescents Undergoing Hip Arthroscopy

BACKGROUND

Acetabular cartilage lesions are a known cause of poor outcomes after hip arthroscopy and are seen regularly among adolescents. However, studies identifying preoperative factors predictive of acetabular cartilage lesions have been limited to adult populations.

PURPOSE

To assess clinical and radiographic predictors of acetabular cartilage lesions in a large cohort of adolescents undergoing hip arthroscopy.

STUDY DESIGN

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

METHODS

Patients undergoing hip arthroscopy for idiopathic femoroacetabular impingement or acetabular labral tears at a children's hospital were reviewed. Demographic predictors were analyzed by use of univariate logistic regression with generalized estimating equations. A matched case-control analysis was subsequently performed to identify radiographic predictors of acetabular cartilage lesions through use of univariate and multivariable conditional logistic regression.

RESULTS

Four hundred two patients (446 hips) undergoing hip arthroscopy between 2010 and 2015 were analyzed. Median age was 16.7 years (range, 13.6-19.0) and 72% of patients were female. Ninety-five hips (21%) were found to have an acetabular cartilage lesion at the time of arthroscopic surgery. Age (odds ratio [OR], 1.7; 95% CI, 1.4-2.1), male sex (OR, 2.5; 95% CI, 1.7-5.0), and body mass index (OR, 1.07; 95% CI, 1.01-1.14) were found to be predictive of intraoperative acetabular cartilage lesions. In the matched case-control analysis, femoral alpha angle as calculated on a Dunn lateral radiograph was independently predictive of an intraoperative acetabular cartilage lesion (OR, 1.8; 95% CI, 1.2-2.6). Additionally, the presence of a crossover sign was independently associated with a decreased odds of an acetabular cartilage lesion (OR, 0.3; 95% CI, 0.1-0.7). On multivariate analysis, alpha angle (Dunn lateral) (OR, 2.0; 95% CI, 1.3-3.1) and crossover sign (OR, 0.2; 95% CI, 0.1-0.7) remained independently associated with the presence of an acetabular cartilage lesion. The presence of an acetabular labral tear was not predictive of an associated cartilage lesion (OR, 1.17; 95% CI, 0.39-3.47; P = .78).

CONCLUSION

In an adolescent population undergoing hip arthroscopy, older age, male sex, and higher body mass index were predictive of acetabular cartilage lesions. From an imaging standpoint, increased alpha angle increased the likelihood of an acetabular cartilage lesion whereas the presence of a crossover sign decreased this likelihood. Predicting the presence of an acetabular cartilage lesion is important when considering a hip arthroscopy procedure to facilitate preoperative planning and to more accurately set patient expectations.

Previous failed hip arthroscopy negatively impacts early patient-reported outcomes of the periacetabular osteotomy: an ANCHOR Matched Cohort Study

Surgical treatment of hip dysplasia by arthroscopic procedures remains controversial. The aim of this study was to compare outcomes of periacetabular osteotomy (PAO) after failed hip arthroscopy to a matched-control group without previous arthroscopy. Fifty-two patients who underwent PAO after failed hip arthroscopy were matched to two subjects without arthroscopy based on age, sex, BMI and radiographic severity. Pre- and post-operative patient self-reported outcomes and radiographic parameters were compared at minimum 1-year follow-up. Prior to PAO the failed hip arthroscopy group exhibited lower modified Harris hip scores (mHHS; 57 versus 62; P = 0.04), WOMAC (59.9 versus 66.3; P = 0.08), UCLA activity (5 versus 7; P = 0.001) and SF12 physical scores (34 versus 40; P = 0.001) compared with the non-arthroscopy group. At minimum 1-year follow-up, the failed hip arthroscopy group had lower mHHS (78 versus 87; P = 0.003); worse WOMAC (84.1 versus 90.8; P = 0.02) and SF-12 physical component (46 versus 50; P = 0.02) with similar UCLA (7 versus 8; P = 0.21) compared with the non-arthroscopy group. No differences were detected regarding radiographic parameters or in patient-reported outcomes from preoperative to follow up. PAO achieved the desired radiographic correction and significant improvement in pain and function after a failed previous hip arthroscopy, however, the patient-reported outcomes were inferior to those of PAO without previous failed arthroscopy.

Concomitant Arthroscopy With Labral Reconstruction and Periacetabular Osteotomy for Hip Dysplasia

In the setting of true hip dysplasia, the high prevalence of intra-articular pathology may lead to recurrent symptoms and failure after periacetabular osteotomy (PAO). Femoral neck osteochondroplasty, microfracture, removal of loose bodies, and labral repair are examples of procedures that are performed with concomitant arthroscopy. When damage to the labrum is too severe to repair, reconstruction instead of extensive debridement before PAO can be more effective in restoring the labral seal to maintain joint lubrication and chondral protection. This Technical Note describes a method for concomitant hip arthroscopy with circumferential labral reconstruction with allograft and PAO.

The Rapidly Assessed Predictor of Intraoperative Damage (RAPID) Score: An In-Clinic Predictive Model for High-Grade Acetabular Chondrolabral Disruption

Background

The preoperative assessment of cartilage lesions is critical to surgical planning and decision making. The accurate radiographic determination of acetabular cartilage damage has remained elusive for modern imaging modalities, including magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA). While risk factors have been individually described, no multivariable system exists for predicting high-grade cartilage damage.

Purpose

To determine the preoperative predictors of grade 3 to 4 acetabular labrum articular disruption (ALAD) lesions.

Study Design

Case-control study; Level of evidence, 3. Cohort study (diagnosis); Level of evidence, 1.

Methods

Retrievable radiographs were reviewed from primary hip arthroscopic procedures performed at 2 high-volume institutions between December 2007 and April 2017. The predictive value of demographic and radiographic factors for the intraoperative documentation of ALAD grade 3 to 4 damage was analyzed and entered into a multivariable model, and a statistically guided scoring system for the damage risk was created using the Akaike information criterion. The scoring system was then prospectively validated on 167 patients who underwent primary hip arthroscopy between April 2017 and February 2018.

Results

A total of 652 primary hip arthroscopic procedures in 614 patients (390 female, 224 male; mean age, 33.2 ± 12.5 years; mean body mass index, 26.9 ± 5.5 kg/m²) from 2007 to 2017 were analyzed. Male sex (odds ratio [OR], 3.11; P < .01), age ≥35 years (OR, 1.96; P < .01), cam morphology (alpha angle >55°) (OR, 2.96; P < .01), and Tönnis grade 1 to 2 (grade 1: OR, 4.14; P < .01, and grade 2: OR, 9.29; P < .01) were univariate risk factors for intraoperatively documented high-grade damage. A multivariable scoring system, the Rapidly Assessed Predictor of Intraoperative Damage (RAPID) score (0-5 points), was generated based on sex, Tönnis grade, and cam morphology. Patients with increasing RAPID scores had an increasing risk of damage, with a 10.5% risk for those with 0 points and an 88.0% risk for those with 5 points (P < .01). The area under the curve was 0.75 for the study group and 0.76 for the validation group (P = .94).

Conclusion

While preoperative MRI has diagnostic value for hip arthroscopic surgery, the RAPID score provides added benefit as a readily employable, in-clinic system for predicting high-grade cartilage damage. The discriminatory value of the RAPID score compares favorably with previous MRI and MRA studies. This information will help the clinician and patient plan for high-grade damage and identify potential targets for cartilage treatment.

Does acetabular coverage influence the clinical outcome of arthroscopically treated cam-type femoroacetabular impingement (FAI)?

Aims

What represents clinically significant acetabular undercoverage in patients with symptomatic cam-type femoroacetabular impingement (FAI) remains controversial. The aim of this study was to examine the influence of the degree of acetabular coverage on the functional outcome of patients treated arthroscopically for cam-type FAI.

Patients and Methods

Between October 2005 and June 2016, 88 patients (97 hips) underwent arthroscopic cam resection and concomitant labral debridement and/or refixation. There were 57 male and 31 female patients with a mean age of 31.0 years (17.0 to 48.5) and a mean body mass index (BMI) of 25.4 kg/m² (18.9 to 34.9). We used the Hip2Norm, an object-oriented-platform program, to perform 3D analysis of hip joint morphology using 2D anteroposterior pelvic radiographs. The lateral centre-edge angle, anterior coverage, posterior coverage, total femoral coverage, and alpha angle were measured for each hip. The presence or absence of crossover sign, posterior wall sign, and the value of acetabular retroversion index were identified automatically by Hip2Norm. Patient-reported outcome scores were collected preoperatively and at final follow-up with the Hip Disability and Osteoarthritis Outcome Score (HOOS).

Results

At a mean follow-up of 2.7 years (1 to 8, sd 1.6), all functional outcome scores significantly improved overall. Radiographically, only preoperative anterior coverage had a negative correlation with the improvement of the HOOS symptom subscale (r = -0.28, p = 0.005). No significant difference in relative change in HOOS subscale scores was found according to the presence or absence of radiographic signs of retroversion.

Discussion

Our study demonstrated the anterior coverage as an important modifier influencing the functional outcome of arthroscopically treated cam-type FAI. Cite this article: Bone Joint J 2018;100-B:831-8.

Is There an Association Between Borderline-to-mild Dysplasia and Hip Osteoarthritis? Analysis of CT Osteoabsorptiometry

BACKGROUND

The definitive treatment of borderline-to-mild dysplasia remains controversial. A more comprehensive understanding of the etiology of osteoarthritis (OA) and clarification of any possible association between borderline-to-mild dysplasia and the pathogenesis of OA are essential.

QUESTIONS/PURPOSES

(1) Does the distribution of acetabular subchondral bone density increase according to dysplasia severity? (2) Is there an association between borderline-to-mild dysplasia and OA pathogenesis?

METHODS

We evaluated bilateral hips of patients with developmental dysplasia of the hip who underwent eccentric rotational acetabular osteotomy (ERAO) for inclusion in the dysplasia group and contralateral hips of patients with unilateral idiopathic osteonecrosis of the femoral head (ONFH) who underwent curved intertrochanteric varus osteotomy (CVO) for the control group. ERAO was performed in 46 patients and CVO was performed in 32 patients between January 2013 and August 2016 at our institution. All patients underwent bilateral hip CT. The study included 55 hips categorized according to dysplasia severity: (1) borderline-mild, 19 hips (15° ≤ lateral center-edge angle [LCEA] < 25°); (2) moderate, 20 hips (5° ≤ LCEA < 15°); (3) severe, 16 hips (LCEA < 5°); and (4) control, 15 hips. Thirty-seven dysplastic hips (age < 15 or > 50 years old, prior hip surgery, subluxation, aspherical femoral head, cam deformity, and radiographic OA) and 17 control hips (age < 15 or > 50 years old, bilateral ONFH, LCEA < 25° or ≥ 35°, cam deformity, and radiographic OA) were excluded. CT-osteoabsorptiometry (OAM) predicts physiologic biomechanical conditions in joints by evaluating subchondral bone density. We evaluated the distribution of subchondral bone densities in the acetabulum with CT-OAM, dividing the stress distribution map into six segments: anteromedial, anterolateral, centromedial, centrolateral, posteromedial, and posterolateral. We calculated the percentage of high-density area, which was defined as the upper 30% of Hounsfield units values in each region and compared least square means difference estimated by the random intercept model among the four groups.

RESULTS

In all regions, the percentage of high-density area did not differ between the borderline-mild group and the control (eg, anterolateral, 16.2 ± 5.6 [95% CI, 13.4 to 18.9] versus 15.5 ± 5.7 [95% CI, 12.4 to 18.5, p = 0.984]; centrolateral, 39.1 ± 5.7 [95% CI, 36.4 to 41.8] versus 39.5 ± 4.7 [95% CI, 36.6 to 42.5, p = 0.995]; posterolateral, 10.9 ± 5.2 [95% CI, 8.0 to 13.8] versus 15.1 ± 6.8 [95% CI, 11.7 to 18.5, p = 0.389]). In the anterolateral region, a smaller percentage of high-density area was observed in the borderline-mild group than in both the moderate group (16.2 ± 5.6 [95% CI, 13.4-18.9] versus 28.2 ± 5.1 [95% CI, 25.5-30.9], p < 0.001) and the severe group (16.2 ± 5.6 [95% CI, 13.4-18.9] versus 22.2 ± 6.8 [95% CI, 19.2-25.2, p = 0.026).

CONCLUSIONS

Our results suggest that the cumulative hip stress distribution in borderline-to-mild dysplasia was not concentrated on the lateral side of the acetabulum, unlike severe dysplasia.

CLINICAL RELEVANCE

Based on the stress distribution pattern, our results may suggest that there is no association between borderline-to-mild dysplasia and the pathogenesis of OA. Further studies are needed to evaluate the association between borderline-to-mild dysplasia and instability of the hip.

Modified Shelf Acetabuloplasty Endoscopic Procedure With Allograft for Developmental Hip Dysplasia Treatment

Hip dysplasia has been identified as one of the leading causes of osteoarthritis. However, hip arthroscopy alone, in the setting of hip dysplasia, remains controversial. In borderline hip dysplasia, with lateral center-edge angle (LCEA) between 18° and 25°, good outcomes have been reported with appropriate capsular and labral management. However, in severe hip dysplasia, with LCEA below 18°, there is an acetabular bony structural deficiency that must be addressed. Even with the potential benefit of hip arthroscopy in addressing intra-articular injuries related to the instability, it cannot be used for soft-tissue procedures. Periacetabular osteotomy remains the gold standard to address that matter; however, its invasive nature along with the long recovery time leaves some patients unwilling to undergo this procedure. New minimally invasive endoscopic procedures, derived from open techniques, describe acetabular autologous bone grafting as an alternative. Donor-side morbidity is always a concern when using autografts; we believe that the use of bone allograft will decrease this potential issue and make the procedure itself less invasive. This Technical Note will describe a type of endoscopic shelf acetabuloplasty using an allograft iliac bone graft.

Progressive osteoarthritis during pregnancy several years following hip arthroscopy for femoroacetabular impingement

Case

A 28-year-old with borderline left hip dysplasia who underwent arthroscopic acetabuloplasty, femoral osteochondroplasty, and labral repair for femoroacetabular impingement. She did well for 8 years, though required arthroscopic capsulolabral adhesion release 2 years after the initial procedure. After this period of stability, she developed left hip pain during pregnancy. Radiographs demonstrated progressive osteoarthritis that lead to total hip arthroplasty at age 37.

Conclusion

The physiologic and hormonal changes during pregnancy leading to increased ligamentous laxity may put vulnerable patients with hip dysplasia and iatrogenic instability at increased risk for progression of osteoarthritis.

Arthroscopic Management for Acetabular Rim Stress Fracture and Osteochondritis Dissecans in the Athlete With Hip Dysplasia

Intra-articular lesions are common in patients with acetabular hip dysplasia. Rim stress fractures (RSFs) have also been described in patients with acetabular hip dysplasia. This lesion is believed to be a result of an unfused secondary ossification center or a stress fracture that could be caused by repetitive impingement of an abnormal-shaped femoral head-neck junction. In addition, osteochondritis dissecans of the acetabulum is a rare condition that can also result from impingement and has been described in patients with hip dysplasia. Here, we describe an arthroscopic technique for internal fixation of osteochondritis dissecans of the acetabulum and concomitant RSF associated with hip dysplasia in a rhythmic gymnast.

Editorial Commentary: Hip Arthroscopy in Hip Dysplasia: Just Because You Are Doing It, Should You?

As surgeons advance the field of hip arthroscopy and perform more hip arthroscopy in patients with hip dysplasia and associated femoroacetabular impingement, we need to publish more outcome studies to determine this procedure's success and safety in this specific group of patients.

Hip Dysplasia: Prevalence, Associated Findings, and Procedures From Large Multicenter Arthroscopy Study Group

PURPOSE

To report observational findings of patients with acetabular dysplasia undergoing hip arthroscopy.

METHODS

We performed a comparative case series of multicenter registry patients from January 2014 to April 2016 meeting the inclusion criteria of isolated hip arthroscopy, a documented lateral center-edge angle (LCEA), and completion of preoperative patient-reported outcome measures. A retrospective analysis compared range of motion, intra-articular pathology, and procedures of patients with dysplasia (LCEA ≤25°) and patients without dysplasia (LCEA >25°).

RESULTS

Of 1,053 patients meeting the inclusion criteria, 133 (13%) had dysplasia with a mean LCEA of 22.8° (standard deviation, 2.4°) versus 34.6° (standard deviation, 6.3°) for non-dysplasia patients. There were no statistically significant differences in preoperative modified Harris Hip Score, International Hip Outcome Tool-12 score, or visual analog scale score (pain). Cam deformity occurred in 80% of dysplasia patients. There was a significant difference in internal rotation between the dysplasia (21°) and non-dysplasia groups (16°, P < .001). Mean internal rotation (33.5°; standard deviation, 15.6°) of the dysplastic subjects without cam morphology was greater than that of the dysplastic patients with cam morphology (18.5°; standard deviation, 11.6°; P < .001). Hypertrophic labra were found more commonly in dysplastic (33%) than non-dysplastic hips (11%, P < .001). Labral tears in patients with dysplasia were treated by repair (76%), reconstruction (13%), and selective debridement (11%); labral treatments were not significantly different between cohorts. The most common nonlabral procedures included femoroplasty (76%) and synovectomy (73%). There was no significant difference between the dysplasia and non-dysplasia groups regarding capsulotomy types and capsular closure rates (96% and 92%, respectively).

CONCLUSIONS

Dysplasia, typically of borderline to mild severity, comprises a significant incidence of surgical cases (13%) by surgeons performing high-volume hip arthroscopy. Despite having similar preoperative pain and functional profiles to patients without dysplasia, dysplasia patients may have increased flexed-hip internal rotation. Commonly associated cam morphology significantly decreases internal rotation. Arthroscopic labral repair, femoroplasty, and closure of interportal capsulotomy are the most commonly performed procedures.

LEVEL OF EVIDENCE

Level III, therapeutic comparative case series.

Predictors of Poor Clinical Outcome After Arthroscopic Labral Preservation, Capsular Plication, and Cam Osteoplasty in the Setting of Borderline Hip Dysplasia

BACKGROUND

Borderline developmental dysplasia of the hip (BDDH) is frequently diagnosed concurrently with cam impingement. While hip arthroscopy has advanced the treatment of hip joint pathology, including femoroacetabular impingement (FAI), arthroscopic treatment for FAI in the setting of BDDH remains a challenge amid a subset of patients. The risk factors of poor clinical results after hip arthroscopic labral preservation and FAI corrections in the setting of BDDH patients have not been well established.

HYPOTHESIS

Pre- and intraoperative findings can predict the poor clinical outcomes after hip arthroscopic surgery for FAI in the setting of BDDH.

STUDY DESIGN

Case control study; Level of evidence, 3.

METHODS

Of patients with BDDH (defined as lateral center edge [LCE] angle between 20° and 25°) who underwent arthroscopic procedures for FAI between 2009 and 2014, 45 met inclusion criteria (45 hips: 15 males and 30 females). Their mean age was 31.4 years (range, 12-65 years), and the mean LCE angle was 23.2°. Clinical and radiographic follow-up evaluations up to a minimum of 2 years after surgery were performed for all patients. Failure of the procedure was defined as conversion to subsequent surgery or having a Tönnis osteoarthritis grade of 2, and success was defined as patients who did not need subsequent surgery. Univariate analysis and Cox hazard proportional analysis were performed for both cohorts.

RESULTS

Of 45 patients, 11 (24%) had revision surgery (endoscopic shelf acetabuloplasty for 5 patients, total hip arthroplasty for 2, and revision hip arthroscopy for 2) or advanced to Tönnis grade ≥2 osteoarthritis and thus constituted the failure group. In the success group, modified Harris Hip Score (median, pre- vs postoperative: 72.1 vs 100, P< .001, Wilcoxon signed-rank test) and nonarthritic hip score (58.8 vs 98.8, P< .001) were significantly improved at the minimum 2-year follow-up. The median age of the failure group was significantly higher than that of the success group (47.0 vs 20.0, P< .001, Mann-Whitney Utest). Risk factors of poor clinical outcomes were identified as follows: age ≥42 years (hazard ratio [HR], 11.6; 95% CI, 2.5-53.9; P= .002, Cox hazard model), broken Shenton line (HR, 6.4; 95% CI, 1.9-22.3; P= .003), Tönnis angle ≥15° (HR, 3.9; 95% CI, 1.2-12.9; P= .03), vertical center anterior (VCA) angle ≤17° (HR, 5.0; 95% CI, 1.5-17.1; P= .01), Tönnis grade 1 at preoperative radiograph (HR, 3.6; 95% CI, 1.1-11.7; P= .04), severe cartilage delamination at acetabulum (HR, 11.8; 95% CI, 3.0-46.1; P< .001), and mild cartilage damage at femoral head (HR, 8.1; 95% CI, 2.1-30.8; P= .002).

CONCLUSION

Preoperative predictors of poorer outcomes from hip arthroscopic labral preservation, capsular plication, and cam osteoplasty in the setting of BDDH are age ≥42 years old, broken Shenton line, osteoarthritis, Tönnis angle ≥15°, and VCA angle ≤17° on preoperative radiographs. Intraoperative predictors of poorer outcomes are severe acetabular chondral damage and even mild femoral chondral damage. Although the patients in the setting of BDDH may have good outcomes from isolated hip arthroscopy, caution is suggested for those with the aforementioned risk factors.