The Dancer's Hip: The Hyperflexible Athlete: Anatomy and Mean 3-Year Arthroscopic Clinical Outcomes

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

BACKGROUND

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

PURPOSE

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

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

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

RESULTS

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

CONCLUSION

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

Dancers Show Significant Improvement in Outcomes and Favorable Return-to-Dance Rates After Primary Hip Arthroscopy With Femoral Head Cartilage Status Being a Predictor of Secondary Surgical Procedures at Mid-Term Follow-Up

PURPOSE

To report minimum 5-year follow-up patient-reported outcome measurement (PROM) scores and return-to-dance rates in dancers who underwent primary hip arthroscopy and to identify predictors of secondary surgical procedures.

METHODS

Prospectively collected data from patients who underwent hip arthroscopy between May 2010 and June 2016 were retrospectively reviewed. Patients were included if they participated in dance at any level 1 year prior to surgery and had preoperative and minimum 5-year follow-up scores consisting of the modified Harris Hip Score, Nonarthritic Hip Score, Hip Outcome Score-Sports Specific Subscale, and visual analog scale pain score. The exclusion criteria were previous hip conditions, previous ipsilateral hip surgery, Tönnis grade greater than 1, or lateral center-edge angle less than 18°. The minimal clinically important difference (MCID) was reported. Dancers who discontinued dance for reasons other than pain in the operative hip were excluded from the return-to-dance analysis. A logistic regression model was used to identify predictors of secondary surgical procedures.

RESULTS

Fifty-one hips (48 female dancers) were included. The average age and average follow-up period were 29.8 ± 17.2 years and 79.1 ± 23.2 months, respectively. Improvement in all PROM scores (P < .001) was reported. Achievement rates of the MCID for the modified Harris Hip Score, Nonarthritic Hip Score, and visual analog scale pain score were 83.3%, 85.7%, and 85.7%, respectively. Revision hip arthroscopy was performed in 5 dancers (9.8%). Conversion to total hip arthroplasty was performed in 4 dancers (7.8%). The return-to-dance rate was 78.6%, with 57.6% returning to the preinjury performance level or a higher level. Higher femoral head Outerbridge grade was identified as a predictor of secondary surgical procedures (P = .045; odds ratio, 6.752 [95% confidence interval, 1.043-43.688]).

CONCLUSIONS

After primary hip arthroscopy, dancers experienced significant improvement in all PROM scores collected and achieved the MCID at a high rate at minimum 5-year follow-up. The return-to-dance rate in dancers who did not discontinue dance because of lifestyle transitions was 78.6%, with 57.6% returning to the preinjury performance level or a higher level. Higher femoral head Outerbridge grade was found to be a predictor of secondary surgical procedures.

LEVEL OF EVIDENCE

Level IV, case series.

Return-to-Sport Rates After Hip Arthroscopy for Femoroacetabular Impingement Syndrome in Flexibility Sports Athletes: A Systematic Review

CONTEXT

Femoroacetabular impingement syndrome (FAIS) is a common cause of hip pain in young adults. Flexibility athletes represent an interesting subset due to the extreme range of motion requirements of their sport.

OBJECTIVE

The objective of this review was to provide a summary of the outcomes of hip arthroscopy for FAIS in patients who participate in flexibility sports.

DATA SOURCES

Three online databases (Medline, Embase, and PubMed) were searched from database inception (1946, 1974, and 1966, respectively) to January 10, 2023.

STUDY SELECTION

Studies were screened for literature addressing surgical outcomes for flexibility athletes undergoing hip arthroscopy for FAIS.

STUDY DESIGN

Systematic review.

LEVEL OF EVIDENCE

Level 4.

DATA EXTRACTION

Various patient-reported outcomes that evaluated the efficacy of hip arthroscopy in this patient population were abstracted and presented in descriptive and analytical format. Abstraction was performed by 2 reviewers.

RESULTS

Overall, a total of 8 Level 3 or 4 studies and 295 patients (312 hips) were included in this review. The pooled standardized mean differences for the Visual Analog Scale for pain score, Modified Harris Hip Score, Hip Outcome Score - Activity of Daily Living scale, and Hip Outcome Score - Sport-Specific Subscale all demonstrated significant improvement after undergoing arthroscopy for FAIS between 12 and 116 months (N = 175, -1.97, 95% CI -2.5 to -1.4, P < 0.01, I2 = 76%; N = 211, 1.82, 95% CI 1.49 to 2.16, P < 0.01, I2 = 52%; N = 164, 1.75, 95% CI 1.42 to 2.05, P < 0.01, I2 = 28%; N = 211, 1.71, 95% CI 1.38 to 2.04, P < 0.01, I2 = 52%, respectively). Across 289 patients, 75.6% to 98% returned to sport at a similar or higher level than presurgery.

CONCLUSION

This review demonstrates a trend of improvement in patient-reported pain, function, quality of life, and return to sport at a minimum of 12 months among flexibility athletes after hip arthroscopy to treat FAIS.

Excellent Clinical Outcomes and Return to Dance of 6 Active, Professional Ballet Dancers Aged Younger Than 40 Years at Total Hip Arthroplasty Through Direct Anterior Approach With a Custom Stem: A Case Report

OBJECTIVE

To report clinical outcomes and return to dance after total hip arthroplasty (THA) by direct anterior approach (DAA) using custom stems in young, active, professional ballet dancers.

DESIGN

Case report.

SETTING

Tertiary.

PATIENTS

Six active, professional ballet dancers younger than 40 years who intended to resume ballet after THA.

INTERVENTIONS

Primary THA by muscle-sparing DAA using custom stems.

MAIN OUTCOME MEASURES

Return to dance, Oxford hip score (OHS), forgotten joint score (FJS), and satisfaction with surgery and pain using numeric rating scale (NRS). CTs were acquired 2 days after surgery to assess implant position. Descriptive statistics were used.

RESULTS

The cohort comprised 4 women and 2 men aged 15 to 39 years. At 2.5 to 5.1 years of follow-up, all patients returned to professional ballet dance. Time to return to dance was 3 to 4 months for 3 patients and 12 to 14 months for 3 patients. Clinical scores were excellent, except for FJS in 1 patient who had considerable pain at her spine and ipsilateral foot. All patients were satisfied with surgery (NRS = 10). There were no complications, reoperations, or revisions. CTs confirmed that stems and cups were correctly positioned.

CONCLUSIONS

All 6 young, active, professional ballet dancers who underwent THA by muscle-sparing DAA using custom stems returned to professional ballet dance and were completely satisfied with surgery. At >2 years of follow-up, 5 patients had excellent clinical outcomes and reported their dancing level to be as expected or better, whereas 1 patient had a lower FJS and was unable to return to her expected dance level.

Arthroscopic Decompression of the Anterior Inferior Iliac Spine

Background

Pathologic contact between the femoral neck and anterior inferior iliac spine (AIIS or subspine) often occurs concomitantly with femoroacetabular impingement, contributing to hip pain and dysfunction1-4. We perform arthroscopic AIIS decompression to alleviate this source of extra-articular impingement and eliminate a potential cause of persistent pain following primary hip arthroscopy5-7.

Description

After identifying abnormal AIIS morphology on preoperative false-profile radiographs and/or 3D computed tomography, we utilize a beaver blade to make a small incision in the proximal capsule and rectus femoris tendon. This peri-capsulotomy window grants access to the subspine region. We then shuttle an arthroscopic burr into place within this window and begin debriding the subspine deformity under direct visualization. Fluoroscopy is utilized intraoperatively to ensure adequate resection, using intraoperative false-profile views achieved by canting the C-arm approximately 40°. Resection is considered adequate when the AIIS deformity is no longer readily apparent on false-profile views and when intraoperative range-of-motion testing confirms no further impingement with hip hyperflexion.

Alternatives

Femoroacetabular impingement can be treated nonoperatively with use of physical therapy and activity modification8; however, outcomes following nonoperative treatment are inferior to those following hip arthroscopy, according to various studies9-12. There are no known alternative treatments specific to subspine impingement.

Rationale

As patients with subspine deformities progress through hip flexion, the femoral neck collides with the AIIS, limiting range of motion. As such, subspine deformities have been shown to be more common in dancers and other high-flexion athletes13,14. Additionally, studies have demonstrated that low femoral version of <5° is associated with increased contact between the distal femoral neck and the AIIS. This pathologic contact can occur even in the absence of an obvious subspine deformity15. In both of these patient populations, surgeons should have a high suspicion for subspine impingement, and a subspine decompression should be performed during hip arthroscopy in order to maximize patient outcomes.

Expected Outcomes

This is a safe procedure that, if performed when indicated, can improve outcomes following primary hip arthroscopy. A recent systematic review found a pooled complication risk of 1.1%, a pooled revision risk of 1.0%, and significant postoperative improvements in patient-reported outcome measures16.

Important Tips

Suspect subspine impingement in high-flexion athletes and patients with low femoral version, even in the absence of an obvious deformity.Ensure adequate visualization of the entire subspine deformity by creating a pericapsular window.Confirm thorough resection with use of fluoroscopic imaging intraoperatively, including false-profile views demonstrating absent subspine deformity.

Acronyms and Abbreviations

FAI = femoroacetabular impingementAP = anteroposterior, refers to the technique used to obtain one of the pelvic radiographs3D CT = three-dimensional computed tomographyLCEA = lateral center-edge angle, a measurement used to quantify severity of hip dysplasiaOR = operating roomAlpha = alpha angle, a measurement used to measure femoral head-neck offset and assess the severity of a cam deformityIc = iliocapsularisRFd = direct head of rectus femorisRFr = reflected head of rectus femorisCap = hip capsuleGMi = gluteus minimusmHHS = modified Harris Hip ScoreHOS-ADL = Hip Outcome Score - Activities of Daily LivingHOS-SSS = Hip Outcome Score - Sports Specific Subscale.

Outcomes of Arthroscopic Decompression of the Anterior Inferior Iliac Spine: A Systematic Review and Meta-analysis

BACKGROUND

Anterior inferior iliac spine (AIIS) impingement has been increasingly recognized as a source of extra-articular impingement and hip pain. However, no aggregate data analysis of patient outcomes after AIIS decompression has been performed.

PURPOSE

To evaluate outcomes after arthroscopic AIIS decompression.

STUDY DESIGN

Meta-analysis; Level of evidence, 4.

METHODS

A systematic review was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. PubMed, EMBASE, and Cochrane Central Register of Controlled Trials were queried for all English-language studies reporting outcomes of arthroscopic AIIS decompression performed in isolation or in conjunction with hip impingement correction surgery. After screening, 10 articles were included. The indications for AIIS decompression were recorded, and weighted mean improvements in patient-reported outcome (PRO) scores, complication rates, and revision rates were calculated.

RESULTS

A total of 547 patients (311 women; 57%) were identified, with a total of 620 operative hips. The mean age was 28.42 ± 5.6 years, and the mean follow-up was 25.22 ± 11.1 months. A total of 529 hips (85%) underwent AIIS decompression, 530 hips (85%) underwent femoral osteochondroplasty, and 458 hips (74%) underwent labral repair. Of the patients, 13% underwent bilateral AIIS decompression. The mean modified Harris Hip Score improved from 61.3 ± 6.9 to 88.7 ± 4.7 postoperatively (change, 27.4 ± 5.7 points; P < .001), the Hip Outcome Score-Activities of Daily Living improved from 67.2 ± 10.6 to 91.1 ± 3.2 postoperatively (change, 24.0 ± 8.0 points; P = .001), and the Hip Outcome Score-Sports Specific Subscale improved from 36.8 ± 19.2 to 82.8 ± 3.8 postoperatively (change, 46.0 ± 18.2 points; P = .002). The pooled risk of postoperative complications was 1.1% (95% CI, 0.1%-2.1%), and the pooled risk of needing revision surgery was 1.0% (95% CI, 0.1%-2.0%). No complication was directly attributed to the AIIS decompression portion of the procedure.

CONCLUSION

PROs improved significantly after hip arthroscopy with AIIS decompression, with a low risk of postoperative complications and subsequent revision surgeries. Failure to identify extra-articular sources of hip pain in outcomes of femoroacetabular impingement syndrome, including from the AIIS, could lead to poorer outcomes and future revision surgery.

Periacetabular Osteotomy in Athletes With Symptomatic Hip Dysplasia Allows for Participation in Low-, Moderate-, and High-Impact Sports, With Greater Than 70% Return to Sport for Competitive Athletes: A Systematic Review

PURPOSE

To systematically review the literature and report the rate of return to sport (RTS) in athletes following periacetabular osteotomy (PAO) for symptomatic hip dysplasia.

METHODS

A literature search of the PubMed, Embase, and Cochrane Library databases was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for clinical studies reporting on athletes undergoing PAO surgery for symptomatic hip dysplasia. A quality assessment was performed using the Methodological Index of Non-Randomized Studies (MINORS) grading system. Data collection included study characteristics, demographics, radiographic measurements, rate and timing of RTS, baseline and most recent patient-reported outcomes (PROs), and subsequent surgeries.

RESULTS

Six studies met inclusion criteria with 341 patients undergoing PAO. There were 2 level III and 4 level IV studies, with an average MINORS score of 11. Preoperative and postoperative lateral center edge angles ranged from 8° to 18° and 23° to 41.3°, respectively. One study reported solely on dancers with a 63% rate of RTS at 1 year postoperatively. Two other studies reported RTS of 80% and 82% for multiple sports, with slightly lower rates (73% and 78%) in competitive athletes. Three studies demonstrated a comparable distribution of sports participation, from the preoperative to postoperative period, in low-impact (61.4% to 72.1% and 63.7% to 85.7%), moderate-impact (10.3% to 21.0% and 4.3% to 25.4%), and high-impact (8.5% to 17.6% and 5.1% to 10.8%) sports. Three studies reported time to RTS after PAO, ranging from 8.8 to 12.8 months. Of the 3 studies noting reasons for not returning to sport, concerns related to the operative hip ranged from 36.4% to 67%. Of the studies that reported both preoperative and postoperative PROs, improvements in all values were observed, with modified Harris Hip Scores and Hip Disability Osteoarthritis Outcome Scores at most recent follow-up ranging from 81 to 95 and 72 to 93, respectively.

CONCLUSIONS

In athletes with symptomatic hip dysplasia undergoing PAO, postoperative participation in low-, moderate-, and high-impact sports was observed, with greater than 70% RTS for competitive athletes. These findings suggest that PAO, with appropriate indications, is an efficacious treatment option in this active patient population with severe dysplasia.

LEVEL OF EVIDENCE

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

Subspine femoroacetabular impingement: retrospective study of a series of patients treated by hip arthroscopic resection

BACKGROUND

Femoroacetabular impingement syndrome (FAIS) is a common hip pathology that causes pain and functional limitation in young patients. subspine femoroacetabular impingement (SFAI) is an increasingly diagnosed extra-articular subtype that occurs from mechanical conflict of the anteroinferior iliac spine (AIIS) with the cervico-diaphyseal junction during hip flexion, which is poorly described in the literature.

QUESTIONS/PURPOSES

We aimed to describe the clinical, functional, and radiological results of the arthroscopic treatment of a group of patients with SFAI treated in our Hip Unit.

STUDY DESIGN

Case series.

METHODS

We present a retrospective study of ten patients with SFAI treated between 2013 and 2020 with arthroscopic resection. Clinical results were assessed with scales such as visual analog scale (VAS); modified Harris Hip Score (mHHS), and Hip disability and Osteoarthritis Outcome Score (HOOS). Radiological results were assessed with radiological measurements, magnetic resonance imaging (MRI), and computed tomography (CT) reconstructions.

RESULTS

Six patients had a Type III AIIS and four of them had Type II. Two patients had previously been surgically treated for FAIS. The range of motion improved in flexion from 107 ± 11 degrees before surgery to 127.5 ± 6 degrees (p = 0.005). MHHS improved from 48.1 (38-75.3) before surgery to 83.1 (57-91) (p = 0.007) and HOOS improved from 65.2 (58-75) to 89 (68.1-100) (p = 0.007). VAS improved from 7.3 (5-9) pre-surgical to 2.5 (0-8) post-surgical (p = 0.005). We did not have significant complications except for an asymptomatic case of heterotopic ossification (Brooker I).

CONCLUSION

Arthroscopic decompression of AIIS in SFAI patients is a safe procedure that provides satisfactory short-term functional results, improving clinical symptoms, function, sports performance, and range of motion in our study.

Editorial Commentary: Restoration of Hip Capsular Tension Is More Important Than Repair Construct Configuration

The debate regarding optimal capsular management during hip arthroscopy has been evolving for over 20 years. Femoroacetabular impingement emerged in the arthroscopic world in the early 2000s. However, the ability to address osseous deformities and decompress and/or reshape them was limited by the hip capsular structures and small capsulotomies. Some surgeons attempted to arthroscopically manage these deformities with limited capsulotomies, with not surprisingly limited success. Others made larger capsular windows (capsulectomies) to more accurately manage these deformities but potentially left some patients with varying degrees of iatrogenic microinstability or macroinstability. Over time, an increasing awareness of post-arthroscopy instability in the form of case reports, case series, and backroom chatter among the hip arthroscopy thought leaders brought the idea of routine capsular closure to the forefront. Biomechanical studies defined the role of the hip capsular ligaments, the deficits created with various capsulotomies during surgery, and the ability to restore stability after capsular repair. Clinical studies revealed better outcomes and lower revision rates after capsular repair for subtle osseous and soft-tissue instability, revision cases, and athletes compared with unrepaired capsulotomies. Various capsular repair constructs (side-to-side repairs, capsular shifts, and various suture configurations and suture materials) have been proposed, without evidence to support a superior technique or suture material. In the end, capsular management is an evolving art that takes into account various patient-specific factors (i.e., individual activity requirements, soft-tissue and osseous parameters, and intraoperative impressions) with the end goal of achieving a stable, impingement-free joint. There might be various capsular management roads to travel, but the destination remains the same.

Hip Pain in Ballet Dancers: Evaluation and Management

Hip and groin injuries are common in ballet dancers, who often begin sport-specific training at a young age. The unique demands of ballet include extreme range of motion, with an emphasis on external rotation and abduction. This creates a distinctive constellation of hip symptoms and pathology in this cohort, which may differ from other flexibility sports. When managing hip symptoms in this cohort, orthopaedic surgeons should consider the unique factors associated with ballet, including ballet-specific movements, morphologic adaptations of the hip, and the culture of the sport. Three common etiologies of hip pain in ballet dancers include femoroacetabular impingement syndrome, hip instability, and extra-articular snapping hip syndrome. First-line treatment often consists of focused physical therapy to strengthen the core and periarticular hip musculature, with surgical management reserved for patients who fail to improve with conservative measures.

Improvement in pain and patient-related outcome measures following hip arthroscopy in patients with femoroacetabular impingement syndrome and concomitant generalized ligamentous laxity: a systematic review

PURPOSE

Within orthopaedic sports medicine, concomitant ligamentous laxity is often found to be a negative prognostic factor for post-operative outcomes following various procedures. The effect of ligamentous laxity on outcomes following hip arthroscopy remains infrequently reported. Therefore, the purpose of this study is to report on the outcomes of hip arthroscopy for the treatment of femoroacetabular impingement syndrome (FAIS) with concomitant generalized ligamentous laxity (GLL).

METHODS

A systematic search was performed in Medline, EMBASE, CENTRAL, and SPORTDiscus (from inception to April 2021) for studies reporting outcomes following hip arthroscopy for symptomatic FAIS in patients with concomitant GLL.

RESULTS

Six studies representing 213 patients and 231 hips were included. Outcomes of pain and functional scores as measured by VAS, Harris Hip Score, and Hip Disability and Osteoarthritis Outcomes Score were tabulated. A mean improvement of 4.8 on VAS was observed. Improvements of 30.0 on HHS, 33.1 for ssHOS, and 23.9 for ADL-HOS were observed.

CONCLUSION

Hip arthroscopy is an effective method of alleviating pain and improving function with statistically significant improvements in all PROM in patients with concomitant FAIS with GLL.

LEVEL OF EVIDENCE

IV.

PROSPERO REGISTRATION

CRD42021248864.

Criteria for Return to Play After Hip Arthroscopy in the Treatment of Femoroacetabular Impingement: A Systematic Review

BACKGROUND

Femoroacetabular impingement (FAI) is a common pathology in athletes that often requires operative management in the form of hip arthroscopy.

PURPOSE

To systematically review the rates and level of return to play (RTP) and the criteria used for RTP after hip arthroscopy for FAI in athletes.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic review of the literature, based on the PRISMA guidelines, was performed using PubMed, Embase, and Scopus databases. Studies reporting outcomes after the use of hip arthroscopy for FAI were included. Outcomes analyzed were RTP rate, RTP level, and criteria used for RTP. Statistical analysis was performed using SPSS software.

RESULTS

Our review found 130 studies, which included 14,069 patients (14,517 hips) and had a mean methodological quality of evidence (MQOE) of 40.4 (range, 5-67). The majority of patients were female (53.7%), the mean patient age was 30.4 years (range, 15-47 years), and the mean follow-up was 29.7 months (range, 6-75 months). A total of 81 studies reported RTP rates, with an overall RTP rate of 85.4% over a mean period of 6.6 months. Additionally, 49 studies reported the rate of RTP at preinjury level as 72.6%. Specific RTP criteria were reported in 97 studies (77.2%), with time being the most commonly reported item, which was reported in 80 studies (69.2%). A total of 45 studies (57.9%) advised RTP at 3 to 6 months after hip arthroscopy.

CONCLUSION

The overall rate of reported RTP was high after hip arthroscopy for FAI. However, more than one-fourth of athletes who returned to sports did not return at their preinjury level. Development of validated rehabilitation criteria for safe return to sports after hip arthroscopy for FAI could potentially improve clinical outcomes while also increasing rates of RTP at preinjury levels.

Little or No Differences in Hip Morphology Between Professional Dancers and Controls: A Systematic Review

OBJECTIVE

To systematically evaluate and synthesize the literature on bony hip morphology of professional dancers, as measured by 2D or 3D imaging techniques.

DATA SOURCES

A literature search was performed on November 20, 2020, using MEDLINE, Embase, and Cochrane. Clinical studies were eligible if they reported on hip morphology of professional dancers. Two independent reviewers screened titles, abstracts, and full-texts to determine eligibility; performed data extraction; and assessed the quality of eligible studies according to the Joanna Briggs Institute (JBI) checklist. This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines.

MAIN RESULTS

The search returned 1384 records; 449 were duplicates, 923 were excluded after title/abstract/full-text screening, and 12 were eligible, reporting on 447 individuals (352 professional dancers and 95 controls). The JBI checklist indicated that 11 studies scored ≥4 points. For professional dancers, lateral center edge angle was 22.4 to 30.8 degrees, acetabular version was 6.7 to 13.5 degrees, neck-shaft angle was 132.5 to 139.5 degrees, and femoral version was 4.7 to 14.4 degrees. Statistically significant differences between dancers and controls were found in some of the studies for acetabular version, neck-shaft angle, and femoral version, although only femoral version showed clinically relevant differences.

CONCLUSIONS

The bony hip morphology of professional dancers is similar to that of other athletes and age-matched controls, which is in contrast to the authors' clinical experience. We presume that the abnormal morphology we have seen at the clinic is only present in symptomatic dancers who require total hip arthroplasty (THA) and is not a general characteristic of all dancers. Further studies should compare the hip morphology of dancers undergoing THA with matched nondancers.

Pathologic Findings on Hip Arthroscopy in High-Level Athletes Competing in Flexibility Sports

BACKGROUND

Athletes who compete in flexibility sports (FS) place unique demands on their hip joints because of the supraphysiologic range of motion required.

PURPOSE

To compare the pathologic features, outcomes, and return-to-sports (RTS) rates of high-level athletes participating in FS who underwent hip arthroscopy for femoroacetabular impingement syndrome (FAIS) and labral tear against a propensity score-matched cohort of high-level athletes participating in non-flexibility sports (NFS).

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Data were prospectively collected and retrospectively reviewed for high-level athletes who underwent primary hip arthroscopy for FAIS from April 2008 to December 2018. Patients who participated in FS such as dancing, gymnastics, martial arts, figure skating, and cheerleading were propensity score matched by body mass index, age at time of surgery, sex, sports competition level, and labral treatment to a cohort of high-level athletes participating in all other sports, such as distance running, soccer, volleyball, and softball. Baseline patient characteristics, intraoperative findings, and surgical procedures were compared. Minimum 2-year patient-reported outcome measures were compared for the modified Harris Hip Score, Nonarthritic Hip Score, Hip Outcome Score-Sport Specific Subscale, and visual analog scale for pain and satisfaction. Rates of secondary surgery and RTS were compared.

RESULTS

A total of 47 patients (50 hips) who participated in FS were included and propensity score matched to 130 patients (150 hips) who participated in NFS. Follow-up time was 37.5 ± 10.4 months (mean ± SD). Most patients (96.0%) were female with a mean age of 19.5 ± 7.3 years. FS athletes had significantly higher rates of femoral head cartilage lesions (Outerbridge ≥2; 12.0% vs 2.0%; P = .008) and ligamentum teres tears (48% vs 26%; P = .003). FS and NFS athletes demonstrated significant clinical improvements after surgery for all patient-reported outcome measures. Of the patients who attempted, 34 (75.6%) participating in FS were able to RTS while 11 (24.4%) were not because of ongoing hip issues. This was not significantly different than the NFS group (P = .073).

CONCLUSION

High-level athletes who participated in FS and were treated for FAIS with hip arthroscopy exhibited higher rates of femoral head cartilage lesions and ligamentum teres tears requiring debridement when compared with a benchmark group of athletes who participated in other sports. Despite this, both groups demonstrated similar improvements in outcome scores and comparable rates of RTS at minimum 2-year follow-up.

Editorial Commentary: Low-Radiation Dose 3-Dimensional Computed Tomography Scan Reconstruction Is the Best Way to Visualize the Anterior Inferior Iliac Spine-For Now

Femoroacetabular impingement comes in several anatomic variations that may coexist, and subspine impingement is a commonly discussed cause of indirect extra-articular hip pathology. Although a classification system to identify and understand anterior inferior iliac spine morphology has been in place for some time, attempts have been made to visualize and understand the anatomy based on other imaging modalities. Standard radiographs are a common part of the initial patient evaluation pathway, along with thorough history taking and physical examination findings. Magnetic resonance imaging scans are obtained typically to evaluate the soft tissue, muscle, ligaments, articular cartilage, and labrum for pathology. For many hip preservation surgeons, a computed tomography scan with 3-dimensional reconstruction is standard protocol for patients who progress along the treatment pathway toward a surgical procedure because understanding the complex hip anatomy is key to successful surgical treatment. Many hip arthroscopy patients are in their young adult years, and we always attempt to reduce the amount of radiation exposure. Eliminating this computed tomography scan and using standard-of-care magnetic resonance imaging to simplify patient care, reduce radiation, and reduce health care costs would certainly be beneficial to our hip preservation patients.

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

Background:

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

Purpose:

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

Study Design:

Systematic review; Level of evidence, 3.

Methods:

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

Results:

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

Conclusion:

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

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

BACKGROUND

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

PURPOSE

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

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

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

RESULTS

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

CONCLUSION

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

Hip Instability in Ballet Dancers: A Narrative Review

BACKGROUND

Dancers possess a large degree of hip range of motion that results from a combination of innate and acquired osseous morphology and permissive soft tissues. Generalized hypermobility in dancers may predispose them to a spectrum of hip instability. The objective of this narrative review is to discuss the anatomical characteristics, pathogenesis, risk factors, clinical signs and symptoms, management, and outcomes of hip instability treatments in dancers.

METHODS

A retrospective search was performed beginning November 1, 2017, for English language articles regarding hip stability in the dancer. Key words used included but were not limited to: dance(r), ballet, hip, hypermobility, range of motion, instability, microinstability, and laxity. PubMed, Scopus, and MEDLINE databases were used.

RESULTS

Forty-three studies were analyzed. Groin pain was found to be the most common presenting symptom of hip instability. A variety of impingement and instability signs may be elicited during physical examination. Hypermobility is frequently observed and is thought to be a necessity for participation in elite levels of ballet. Radiographs and advanced planar imaging (magnetic resonance imaging and computed tomography) should be scrutinized to evaluate for dysplasia, cam, pincer, subspine, and rotational morphologies. Dysplasia (low volume acetabulum), cam morphology, femoral retroversion, and coxa valga are common findings in the ballet dancers' hip. Labral injuries and ligamentum teres tears are common and may potentiate instability in the hip. Management options include education, oral non-opioid medications, activity modification, exercise prescription, and surgery. Reported outcomes of these treatments in ballet are limited.

CONCLUSION

Hip hypermobility is prevalent in the ballet population and is a clear advantage. However, it may increase the risk of instability. It is important to identify the multifactorial osseous and soft tissue etiology of hip or groin pain in dancers. Practitioners should have a high level of suspicion for hip instability in the dancer presenting with hip pain and treat accordingly. There is a significant need for increased quantity and quality of investigation into the outcomes of treatment for hip instability in the dancer.

Hypermobile Disorders and Their Effects on the Hip Joint

Hypermobility, or joint hyperlaxity, can result from inherited connective tissue disorders or from micro- or macrotrauma to a joint. The supraphysiologic motion of the hip joint results in capsuloligamentous damage, and these patients have a propensity to develop femoroacetabular impingement syndrome (FAIS) and labral injury. In this review, the recent literature evaluating the definitions, history, incidence, genetics, and histology of hypermobile disorders is investigated. We then review the clinical evaluation, natural history, and resulting instability for patients presenting with a hypermobile hip. Lastly, treatment options and outcomes will be highlighted.

Capsule-Preserving Approach to Arthroscopic Decompression of the Anterior Inferior Iliac Spine

Hip arthroscopy techniques have evolved to treat a wide range of extra-articular pathologies. Subspine impingement commonly occurs in femoroacetabular impingement, particularly in athletes with a high range of motion, patients with low degrees of femoral version, and those with large subspine deformities. A reliable technique that preserves the hip capsule would be helpful for hip arthroscopy surgeons. This note details our technique using pericapsular windows proximal to the interportal capsulotomy to access and decompress a subspine deformity in the setting of hip femoroacetabular impingement.

Editorial Commentary: The Competitive Dancer's Hip-An Acquired Flexible Attitude to a High-Performance Hip

Competitive dancers have a high prevalence of hip injuries. The dancer's hip is a unique scenario in which hip impingement is associated with compensatory soft-tissue laxity. Particularly in these athletes, normal osseous hip morphology with symptomatic femoroacetabular impingement may be observed. The repetitive training, including extreme daily hip range of motion, results in compensatory soft-tissue laxity and secondary impingement-induced subluxation. Peculiarly, hip impingement in dancers occurs in the posterosuperior aspect of the hip and extra-articularly between the anterior inferior iliac spine and the distal femoral neck (subspinous impingement). Normal or even dysplastic hips might impinge during extreme range of motion. An atypical osteochondroplasty, including a subtle distal-based femoral resection, anterior inferior iliac spine decompression, and excellent management of the capsule, should be considered in this population for a successful outcome. Hip dysplasia should always be ruled out in these athletes, and if present, a periacetabular osteotomy should be indicated.