- Email: [email protected]
The Dancer’s Hip: The Hyperflexible Athlete: Anatomy and Mean 3-Year Arthroscopic Clinical Outcomes
The Dancer’s Hip: The Hyperflexible Athlete: Anatomy and Mean 3-Year Arthroscopic Clinical Outcomes Christopher M. Larson, M.D., James R. Ross, M.D., M. Russell Giveans, Ph.D., Rebecca Stone McGaver, M.S., A.T.C., Katelyn N. Weed, M.S., and Asheesh Bedi, M.D.
Purpose: To report preoperative anatomy, patient-related outcomes measures, and return to dance rates in a cohort of competitive dancers undergoing an arthroscopic hip procedure. Methods: Competitive dancers who underwent an arthroscopic hip procedure between 2008 and 2016 were included. Specific types of dance performed, morphology, and radiographic parameters were documented. Outcomes were evaluated with Modified Harris Hip Score (mHHS), the 12-Item Short Form Health Survey, visual analog scale, and Hip Disability and Osteoarthritis Outcome Scores (HOOS). Results: There were 63 competitive dancers (77 hips) with a mean age 21.2 years in the current study. Specific types of dance performed included 57 studio dance and 41 high-kick dance, and 28 dancers (44%) were professional-level. Morphology included cam-type femoroacetabular impingement (95%), pincer-type femoroacetabular impingement (40%), anterior inferior iliac spine impingement (subspine) (83%), and mild (borderline) dysplasia (11%). Procedures performed included 95% labral repairs, 5% labral debridements, 99% femoral resections, 49% rim resections, 88% subspine decompressions, and 66% capsular plications. At mean 36 months’ follow-up post-arthroscopy, the mean outcome improvements were 25.6 points (mHHS), 18.9 points (HOOS-activities of daily living), 29.9 points (HOOSSports), 8.7 points (12-Item Short Form Health Survey), and 3.7 points (visual analog scale) (P < .01 for each). Scores were significantly improved from preoperatively to most recent follow-up for mHHS (60.0 vs 85.6 points), HOOS-activities of daily living (72.5 vs 91.5 points), and HOOS-Sports (49.7 vs 79.6) (P < .01). Sixty-three percent of dancers returned to their previous level of competitive dance, 21% returned to limited or modified dance, and 16% were unable to return to dance, including 1 retirement. Conclusions: A careful arthroscopic approach to address cam-type pathomorphology, highly prevalent subspine impingement, and capsular laxity in competitive dancers can achieve a modest rate of return to sport and good-to-excellent patient-reported outcomes at short- to mid-term (3-year) follow-up. Eighty-four percent of dancers ultimately returned to competitive dance, although only 63% returned to their preinjury competitive level. Level of Evidence: IV, case series.
H
ip injuries represent up to 50% of injuries in dancers.1,2 A study evaluating professional ballet dancers reported that 21.6% noted a history of hip problems or injuries that correlated with greater pain scores and lower quality of life scores compared with those without a history of hip problems.3 Motion analysis and magnetic resonance imaging (MRI) studies
in dancers in a splits position have reported significant femoroacetabular impingement (FAI)-induced subluxation even in normal or dysplastic hips, with a predominance of stress at the posterosuperior hip joint proper.4,5 Because of the increased demands placed on the hips secondary to high range of motion requirements, even in the setting of normal or dysplastic
From Twin Cities Orthopedics, Edina, Minnesota (C.M.L., M.R.G., R.S.M., K.N.W.); BocaCare Orthopedics, Deerfield Beach, Florida (J.R.R.); and Department of Orthopedics, University of Michigan MedSport, University of Michigan, Ann Arbor, Michigan (A.B.), U.S.A. The authors report the following potential conflicts of interest or sources of funding: C.M.L. reports personal fees from Smith & Nephew, outside the submitted work; J.R.R. reports personal fees from Smith & Nephew, outside the submitted work; M.R.G. reports personal fees from Ortholink Pty, Ltd., and personal fees from Superior Medical Experts, outside the submitted work; and A.B. reports personal fees and other from Arthrex, outside the submitted
work. Full ICMJE author disclosure forms are available for this article online, as supplementary material. Received April 24, 2019; accepted September 13, 2019. Address correspondence to Christopher M. Larson, M.D., Twin Cities Orthopedics, 4010 West 65th St., Edina, MN 55435. E-mail: chrislarson@tcomn. com Ó 2019 by the Arthroscopy Association of North America 0749-8063/19144/$36.00 https://doi.org/10.1016/j.arthro.2019.09.023
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol
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anatomy, management of these hips is controversial and challenging.6,7 There is very little published literature reporting outcomes after hip arthroscopy in competitive dancers. The purpose of the current study is to report preoperative anatomy, patient-related outcomes measures, and return to dance rates in a cohort of competitive dancers undergoing an arthroscopic hip procedure. The hypothesis was an arthroscopic approach managing the labrum, subspine impingement, and subtle impingementeinduced instability would result in the ability to return to dance, albeit at a level inferior to that historically seen for athletes in other less hipdemanding sports.
Methods Between December 2008 and December 2016, all competitive dancers who underwent hip arthroscopy for hip jointerelated pain by the senior author (C.M.L.) and minimum 1-year follow-up were included for retrospective review. Competitive dance was defined as organized competitive high school, collegiate, dance company, or professional dance (high kick, dance line, or studio dance) that was considered the athletes primary sport. This study was approved by an institutional review board (University of Minnesota: 1308M40962). All patients presented with anterior, groin-related pain with dance activities recalcitrant to physical therapy and activity modification. Impingement testing (flexion, adduction, and internal rotation testing) was positive for all patients and recreated the patients’ presenting complaints. All patients had evidence for a labral tear on MRI. Preoperative imaging for all patients, in addition to MRI, included a standing anteroposterior (AP) pelvis radiograph of both hips, a 45 modified Dunn radiograph and false profile radiograph of the affected hip, and 3-dimensional computed tomographic scans (3DCT) of the affected hip. Patients with arthritic changes (greater than Tönnis 0-1 changes on plain radiographs, MRI bipolar outerbridge changes grade 3-4), inflammatory arthropathy, or radiographically confirmed evidence of osseous hip instability (as defined by femoral head lateralization, extrusion and/or break in Shenton’s line on imaging) were excluded from the study. In general, a Tönnis angle >13 and any femoral head lateralization or migration, and predominance of dysplastic features were considered relative contraindications for hip arthroscopy. Although a specific lateral center edge angle (LCE) was not an absolute exclusion, an LCE below 20 to 25 was a relative contraindication if there was a predominance of instability rather than impingement clinical presentation. Lower LCEs were occasionally considered for hip arthroscopy, as a pelvic osteotomy might lead to some decreased mobility that could be detrimental in this patient population.
Radiographs were assessed with measurements of lateral center edge angle, Tönnis angle, and alpha angle, presence or absence of a cross-over sign (COS), posterior wall sign (PWS), and prominent ischial spine sign. These measurements were performed in a blinded fashion and independently by a fellowship-trained sports medicine hip-preservation surgeon (J.R.R.) to assess acetabular and proximal femur morphology. Patient-reported outcomes measures were obtained preoperatively and postoperatively and included the modified Harris hip score (mHHS), pain on a visual analog scale, 12-Item Short Form Health Survey, and hip disability and osteoarthritis outcomes score (HOOS) (activity of daily living [ADL] and Sports). All physical examinations were performed by the senior author (C.M.L.). The current arthroscopic approach for hip disorders has been previously described by the senior author.8-10 Arthroscopy was performed with the patient in the supine position and procedures performed as indicated, including rim resections for pincer-type FAI, femoral resections for cam-type FAI (lateral alpha angle >50 ) or high range of motion (ROM) femoral neck impingementeinduced subluxation (visualized arthroscopically), anterior inferior iliac spine (AIIS) decompressions for subspine (AIIS) impingement, labral repair versus debridement for labral pathology, chondral debridement and or microfracture for chondral pathology, capsular repair for all hips with additional capsular plications, or shift for associated capsular laxity. The capsule was fully repaired in all cases, but in cases of laxity, the tissue was shifted and overlapped, and in some cases repaired side to side after excision of additional capsule both to increase thickness and eliminate redundancy. This assessment is admittedly subjective but is based on assessment of the available tissue and redundancy observed in the iliofemoral ligament after interportal capsulotomy is completed, with abnormal mobility of the capsule assessed intraoperatively. The capsule was mobilized with a hook to evaluate for excessive redundancy and a shift or plication (excision of additional capsule and side to side repair) on a caseby-case basis. Abnormal motion patterns and high ROM conflicts were assessed preoperatively with dynamic analysis on preoperative planning software (PLAN; Smith & Nephew, Andover, MA) and confirmed intraoperatively by concordant areas of coup and contra-coup injury to the labrum and chondrolabral junction, sclerosis at the distal femoral headeneck junction, ecchymosis in the region of the AIIS, and visualization of levering of the femoral neck at the extremes of hip abduction intraoperatively (Fig 1 A-E). AIIS morphology was classified as Type I-III as defined by Hetsroni et al.11 based on preoperative false-profile radiograph and 3DCT scan images. Distal and
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Fig 1. (A) Modified Dunn lateral radiograph reveals camtype morphology (arrows) with extension of the sclerosis distally to the greater trochanter. (B) Modified Dunn lateral radiograph after femoral resection (arrows) including distal resection to the greater trochanter. (C) Intraoperative image of a left hip reveals capsular ecchymosis indicative of subspine/high range of motion impingement. (D) Intraoperative image of the right hip reveals anterior labral ecchymosis indicative of subspine/high range of motion impingement. (E) 3DCT image of the left hip after dynamic motion analysis reveals impingement between the AIIS and medial femoral neck with high flexion range of motion (blue areas). (3DCT, 3-dimensional computed tomography; AIIS, anterior inferior iliac spine.)
posterolateral femoral and occasionally posterolateral rim resections, subspine (AIIS) decompressions, and capsular management were typically the focus in this patient population. Patients were typically kept toetouch weight bearing postoperatively after arthroscopy for 2 to 3 weeks without a brace or continuous passive motion machine. Physical therapy including early mobilization and ROM with circumduction or well-leg cycling was begun postoperative day 0 or 1.
Return to dance-specific activities began as early as 3 months with full return to dance when pain-free ROM and normal functional progression were achieved at the discretion of a dance-focused physical therapist.
Statistical Analysis Independent samples t tests and paired samples t tests were used where appropriate to determine differences in outcomes scores, with the minimally important
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clinical difference for mHHS and HOOS defined as 10 and 8 points, respectively.12 Univariate regression analyses were used to determine statistical correlations between outcomes and preoperative and postoperative radiographic parameters. c2 analyses were used to determine differences in prevalence rates. Statistical analyses were performed using SPSS v21 (IBM Corp., Armonk, NY). Significance was set at P < .05.
Results Sixty-three competitive dancers (77 hips, 61 female, 2 male) with a mean age 21.2 years (range 13-62 years) were identified between December 2008 and December 2016 and all met the inclusion criteria. Twenty-eight (28) of the 63 athletes (44%) were professional dancers. There were 37 right and 40 left hips. The mean follow-up time was 36 months (range 12-116 months). There were 35 hips (29 dancers) who participated in only studio dance (ballet, jazz, tap, modern, contemporary, lyrical) and 19 hips (14 dancers) who participated in only dance line (high kick). Twenty-two hips (19 dancers) participated in both studio and high kick and 1 hip (1 dancer) did not report the style of dance. Based on plain radiographs and 3DCT imaging, 94.8% of hips (73 hips) had evidence of cam-type FAI (lateral alpha angle >50 13,14). Pincer type FAI (nondysplastic retroversion [LCE >25 ], positive COS, and negative posterior wall sign) was present for 32.5% of hips (25 hips), and profunda (LCE >40 ) was present for 8.1% of hips (6 hips). Subspine impingement was present in 83.1% of hips (64 hips). Borderline (LCE 20 to <25 ) or mild dysplasia (LCE <20 ) was present in only 11% (8 hips) in this case series. Based on preoperative plain radiographic measures (Table 1), the mean LCE was 30.3 (range 16 -44 ), the mean Tönnis angle was 4.2 (range, e4.8 to 14 ), the mean alpha angle was 61.3 (range 40 -90 ) on AP radiographs, and the mean alpha angle was 65.2 (range 45 -84 ) on lateral radiographs. A positive COS was present in 63.6% of hips (49 hips), and a PWS was present in 45.5% of hips (35 hips), indicating acetabular retroversion. No radiographs had femoral head lateralization or extrusion, widening of the medial clear space, and all had continuity of Shenton’s line. Procedures performed included 73 labral repairs (95%), 4 labral debridements (5%), 76 femoral resections (99%) including distal-based resection for high ROM-induced impingement in otherwise-normal alpha angles (73/77 patients had elevated lateral alpha angles), 38 rim resections (49%) including 9 hips (11.7%) undergoing posterior rim resections, 68 subspine decompressions (88%), 51 capsular plications (66%), and 2 psoas tenotomies early in this cohort (3%). In addition, 3 patients had documented EhlerseDanlos syndrome. Psoas tenotomies were not performed later in this series secondary to the risk of hip flexion strength
and active ROM deficits and potential stabilizing role of the psoas tendon in this patient population. One (1%) acetabular microfracture was performed as well as 65 acetabulum chondroplasties (84%) and 1 femoral chondroplasty (1%). At mean 36-month follow-up time, the mean mHHS improved from a preoperative score of 60.02 (range 3198 points) to a most recent score of 85.63 points (range 47-100 points) for a mean overall improvement of 25.61 points (P < .01). The mean HOOS-ADL improved from a preoperative score of 72.52 (range 21-100 points) to a most recent score of 91.47 points (range 53100 points) for a mean overall improvement of 18.95 points (P < .01). The mean HOOS-Sports improved from a preoperative score of 49.73 (range 0-100 points) to a most recent score of 79.57 points (range 25-100 points) for a mean overall improvement of 29.85 points (P < .01). There were also statistically significant overall improvements for 12-Item Short Form Health Survey (8.69 points, P < .01) and visual analog scale scores (3.65 points, P < .01). The majority of dancers achieved minimally important clinical difference for mHHS, HOOS-ADL, and HOOS-Sports (Table 2). There were no statistically significant differences in outcomes based on diagnosis or procedures performed in the cohort (P > .05). Sixty-three percent of dancers returned to their previous level of competitive dance, 21% returned to limited or modified dance, and 16% were unable to return to dance, including 1 retirement. No patients have required conversion to total hip arthroplasty or undergone a revision arthroscopic procedure to date. Standard traction and post-based techniques were used at the time of the study, and there were no tractionrelated complications and specifically no pudendal nerve injuries or perineal soft-tissue injury in any patient. Regarding plain radiographic measures, the mean AP radiograph alpha angle improved from 61.3 (range 40 -90 ) to 47.9 (range 38 -85 ) and the mean lateral radiograph alpha angle improved from 65.2 (range 45 -84 ) to 43.4 (range 35 -83 ). On the acetabular side, a positive COS was present in 63.6% of hips (49 hips) preoperatively compared with 27.3% of hips Table 1. Preoperative and Postoperative Plain Film Radiographic Measurements Radiographic Measurement LCEA Tönnis angle AP alpha angle Lateral alpha angle Prevalence of crossover Prevalence of PWS
Preoperative, Mean 30.3 4.2 61.3 65.2 49/77 35/77
Postoperative, Mean 28.9 4.9 47.9 43.4 21/77 56/77
P Value .004 .001 <.001 <.001 <.001 <.001
AP, anteroposterior; LCEA, lateral center edge angle; PWS, posterior wall sign.
THE DANCER’S HIP Table 2. Preoperative and Postoperative Outcome Scores
PROMs mHHS HOOS-ADL HOOS-Sports VAS SF-12
Preoperative
Postoperative
Mean 60.0 72.5 49.7 6.0 77.2
Mean 85.6 91.5 79.6 2.4 85.6
P Value <.01 <.01 <.01 <.01 <.01
MCID 82.9% 73.5% 76.3% e e
ADL, activities of daily living; HOOS, Hip Disability and Osteoarthritis Outcome Scores; MCID, minimally important clinical difference; mHHS, modified Harris Hip Score; PROMs, patient-reported outcome measures; SF-12, the 12-Item Short Form Health Survey; VAS, visual analog scale.
(21 hips) postoperatively. There were significant changes pre- to postoperatively for the Tönnis angle (P ¼ .001), AP alpha angle (P < .001), and prevalence of a PWS (P < .001). All but 3 hips had 3DCT scans and the mean femoral version was 17.49 (range e8.0 to 38.0). There was no statistically significant relationship between femoral version and return to dance rates (P ¼ .089) and patient-related outcome measures (P ¼ .311).
Discussion A careful arthroscopic approach to address cam-type pathomorphology, prevalent subspine impingement, and capsular laxity in competitive dancers can achieve a high rate of return to sport and good-to-excellent patient-reported outcomes at short- to mid-term followup. In addition, the femoral resection was continued posterolaterally in most cases, and 11.7% of hips underwent posterior rim resections, with posterosuperior FAI being more prevalent in dancers with frequent abduction and external rotation (ER) maneuvers. The current study evaluated a cohort of 63 competitive dancers (77 hips, 28 hips [44%] professional dancers) and demonstrated significant improvements in outcomes (25.61 points MHHS, 18.95 points HOOS-ADL, and 29.85 points HOOS-Sports) and an 84% rate of return to dance (63% preinjury level without modifications) after hip arthroscopy at mean 3-year follow-up. The dancer’s hip in the current study is characterized by subtle FAI with a predominance of mild cam-type morphology, decreased head neck offset (distal based cam) and posterolateral femoral sided impingement, highly prevalent subspine (AIIS) impingement, acetabular retroversion, and capsular laxity. Although dysplasia has been reported to be prevalent in the performing arts and dancers,11 only 11% of the hips in this cohort had dysplastic features and was likely secondary to selection criteria for arthroscopic management. Those with more significant dysplastic features (LCE <20 and Tönnis angle >13 ) generally are not offered an arthroscopic approach in the senior author’s practice.
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There are exceptions when the Tönnis angle was higher and LCE was lower, and the clinical presentation favored impingement rather than instability where arthroscopy was ultimately offered. Although periacetabular osteotomy might be considered with these radiographic parameters for other individuals, this might lead to motion loss that could be detrimental for higher-level dancers. There is very limited outcomes data with regards to hip arthroscopy and performing arts and dance. Hammoud et al.15 reported on 41 professional dancers in New York City. Fifty-five percent of the dancers had dysplastic hips, 25% had FAI, and 22% were reportedly normal.15 Ballet dancers (60% return to dance) and those hips with dysplasia (64% return to dance) were the least likely to return to dance. This is likely secondary to underlying instability not addressed by an arthroscopy and or the extreme hip ROM requirements in this challenging patient population. In addition, the specific procedures performed in this cohort of professional dancers are not clear.15 There has been only one report of 44 hips in dancers undergoing periacetabular osteotomy for more significant hip dysplasia (mean LCE 10.7 , mean Tönnis angle 19.7 ) with a median followup of 2.7 years.16 Although the level of dance or type of dance was not specified, 63% ultimately returned to dance compared with 88% in the current study. The patients undergoing periacetabular osteotomy in that study, however, had a greater degree of dysplasia, as indicated by the lateral center edge angle in comparison with the current study. There was an improvement postoperatively of 17 points (mHHS) and 20 points (HOOS) with a final mHHS of 86.3 points and final HOOS-Sports of 77.3 points at most recent follow-up.16 This is in line with the improvements seen in the current study (improved mHHS 26 points, final mHHS 86 points, improved HOOS-Sports 29.8 points, final HOOS-Sports 79.6 points). Dancers represent a unique group of athletes and performers that requires a high range of motion-based activities.2,6,7,17 Different dancing techniques and styles have different hip joint requirements.2,6,7,17 High-kick dance (dance line), for instance, requires extreme hip flexion for the kick leg and extreme hip extension for the support leg. Ballet hip requirements are more demanding, requiring a combination of extreme hip flexion, extension, abduction, and ballistic movement patterns.2,6,7,17 Previous studies have demonstrated that these high ROM positions (i.e., splits positions) create impingement-induced instability and even subluxation in hips with normal osseous anatomy (absence of FAI or dysplasia).4,5 One study using motion analysis in 11 ballet dancers demonstrated a high frequency of impingement and subluxation with abduction and ER movements seen during developpe a la second, grand ecart facial, grand ecart lateral, and
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grand plié positions.4 The primary zones of impingement were typically superior and posterosuperior.4 It is the current author’s observations during surgery that during extreme hip flexion (high kick), the AIIS (subspine region) contacts the medial distal femoral neck along the medial synovial fold, whereas in extreme hip abduction the acetabular rim contacts the lateral distal femoral neck along the lateral synovial folds. Since normal hips or even dysplastic hips might impinge in extreme hip ROM, the current author believes that distal-based femoral resections along the medial and lateral synovial folds (99% in the current study) in addition to subspine decompressions (83.3% in the current study) and occasionally posterior rim resections (11.7% in the current study) might in part be responsible for the improved outcomes observed in the current study. Femoral version might also have implications regarding the ROM profile of the hip. Extreme lower-extremity ER is required to achieve turn-out. It might be advantageous to have increased femoral retroversion to achieve greater degrees of lower-extremity ER. Studies are somewhat contradictory with regards to this topic. One study in ballet dancers showed similar measures of femoral version versus non-dancing controls,18 whereas another study demonstrated greater degrees of femoral retroversion in ballet dancers who underwent >6 hours of ballet a week between the ages of 11 and 14 years, possibly indicating an effect of ballet on the developing physis not unlike proximal humeral retroversion seen in throwing athletes.19 In the current study, a number of dance styles and techniques were observed as opposed to strictly ballet, but the overall femoral version of 17.5 (normal reportedly around 10 ) was not consistent with relative femoral retroversion in this patient population. The approach for management of these hyperflexible, extreme ROM, subtle FAI hips has arisen from experience in this population and continues to evolve. Subtle distal-based femoral resections medially and laterally and AIIS decompressions are performed to increase the impingement and subluxation-free hip ROM. Labral repair is performed which, in addition to providing a seal, might provide a degree of stability in these hips with soft-tissue laxity and or dysplastic variants. The capsule is carefully evaluated and repair in every case with plications or shifts reserved for excessive capsular laxity and incompetence to potentially increase stability. Care should be taken to avoid overtensioning the capsule, which could result in loss of ER and subsequent turnout and could be detrimental to a competitive dancer. No patients in the current study experienced ER loss, and care was taken to close, shift, or plicate the capsule with the hip near full extension and ER to prevent loss of ER or turnout in this patient population.
Limitations Limitations for the current study include the retrospective design and all of the associated bias and limitations. Three years is not long-term follow-up and with the high demands placed on the hips by these performers, and longer-term follow-up is critical from an outcomes and sustained return to play and performing standpoint. In addition, management of these subtle deformities, dysplastic variants, and soft-tissue laxity cases are evolving rapidly, and the management of these cases over the 5-year study period may have differed based on this evolution. Although only 11% of the cases had evidence for dysplastic features, there is a selection bias for those potentially benefiting from arthroscopic management rather than being representative for all competitive dancers or performing artists in general. Correspondingly, the variable and individualized nature of the surgical intervention is a challenge to objectify and a limitation. Therefore, the current outcomes should not be generalized to all dancers where radiographic dysplasia and potential clinical instability has shown to predominate from a morphologic standpoint. Although competitive dancing athletes almost certainly demonstrate some hyperlaxity, Beighton scores were not formally assessed in this population, and we cannot comment regarding this potentially important topic. Finally, there is some variability in the procedures that are performed for each individual patient as well as the variability of levels of dancing, thus making generalizability more difficult.
Conclusions A careful arthroscopic approach to address camtype pathomorphology, highly prevalent subspine impingement, and capsular laxity in competitive dancers can achieve a modest rate of return to sport and good-to-excellent patient-reported outcomes at short to mid-term (3 years) follow-up. Eighty-four percent of dancers ultimately returned to competitive dance, although only 63% returned to their preinjury competitive level.
References 1. Bronner S, Brownstein B. Profile of dance injuries in a Broadway show: A discussion of issues in dance medicine epidemiology. J Orthop Sports Phys Ther 1997;26:87-94. 2. Reid DC, Burnham RS, Saboe LA, Kushner SF. Lower extremity flexibility patterns in classical ballet dancers and their correlation to lateral hip and knee injuries. Am J Sports Med 1987;15:347-352. 3. Gross C, Rho M, Aguilar D, Reese M. Self-reported hip problems in professional ballet dancers: The impact on quality of life. J Dance Med Sci 2018;22:132-136. 4. Charbonnier C, Kolo FC, Duthon VB, et al. Assessment of congruence and impingement of the hip joint in professional ballet dancers: A motion capture study. Am J Sports Med 2011;39:557-566.
THE DANCER’S HIP 5. Duthon VB, Charbonnier C, Kolo FC, et al. Correlation of clinical and magnetic resonance imaging findings in hips of elite female ballet dancers. Arthroscopy 2013;29: 411-419. 6. Weber AE, Bedi A, Tibor LM, Zaltz I, Larson CM. The hyperflexible hip: Managing hip pain in the dancer and gymnast. Sports Health 2015;7:346-358. 7. Hamilton WG, Hamilton LH, Marshall P, Molnar M. A profile of the musculoskeletal characteristics of elite professional ballet dancers. Am J Sports Med 1992;20: 267-273. 8. Larson CM. Arthroscopic management of hip pathomorphology. Instr Course Lect 2012;61:287-293. 9. Larson CM, Giveans MR. Arthroscopic management of femoroacetabular impingement: Early outcomes measures. Arthroscopy 2008;24:540-546. 10. Larson CM, Giveans MR. Arthroscopic debridement versus refixation of the acetabular labrum associated with femoroacetabular impingement. Arthroscopy 2009;25: 369-376. 11. Hetsroni I, Poultsides L, Bedi A, Larson CM, Kelly BT. Anterior inferior iliac spine morphology correlates with hip range of motion: A classification system and dynamic model. Clin Orthop Relat Res 2013;471:2497-2503. 12. Harris JD, Brand JC, Cote MP, Faucett SC, Dhawan A. Research pearls: The significance of statistics and perils of pooling. Part 1: Clinical versus statistical significance. Arthroscopy 2017;33:1102-1112.
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13. Beaule PE, LeDuff M, Zaragoza EJ. Quality of life following femoral head-neck osteochondroplasty for femoroacetabular impingement. J Bone Joint Surg Am 2007;89:773-779. 14. Tannast M, Siebenrock KA, Anderson S. Femoroacetabular impingement: Radiographic diagnosisdwhat the radiologist should know. AJR Am J Roentgenol 2007;188:1540-1552. 15. Hammoud S, Brown HC, Kelly BT, Padgett DE. Hip Arthroscopy in the Professional Dancer. San Diego, CA: Paper presented at the 2011 Annual Meeting of the American Academy of Orthopaedic Surgeons, February 15-19, 2011. 16. Novais EN, Thanacharoenpanich S, Seker A, et al. Do young female dancers improve symptoms and return to dancing after periacetabular osteotomy for the treatment of symptomatic hip dysplasia? J Hip Preserv Surg 2018;5: 150-156. 17. Kushner S, Saboe L, Reid D, Penrose T, Grace M. Relationship of turnout to hip abduction in professional ballet dancers. Am J Sports Med 1990;18:286-291. 18. Bauman PA, Singson R, Hamilton WB. Femoral neck anteversion in ballerinas. Clin Orthop Relat Res 1994: 57-63. 19. Hamilton D, Aronsen P, Løken JH, et al. Dance training intensity at 11-14 years is associated with femoral torsion in classical ballet dancers. Br J Sports Med 2006;40: 299-303. discussion 303.
Purpose: To report preoperative anatomy, patient-related outcomes measures, and return to dance rates in a cohort of competitive dancers undergoing an arthroscopic hip procedure. Methods: Competitive dancers who underwent an arthroscopic hip procedure between 2008 and 2016 were included. Specific types of dance performed, morphology, and radiographic parameters were documented. Outcomes were evaluated with Modified Harris Hip Score (mHHS), the 12-Item Short Form Health Survey, visual analog scale, and Hip Disability and Osteoarthritis Outcome Scores (HOOS). Results: There were 63 competitive dancers (77 hips) with a mean age 21.2 years in the current study. Specific types of dance performed included 57 studio dance and 41 high-kick dance, and 28 dancers (44%) were professional-level. Morphology included cam-type femoroacetabular impingement (95%), pincer-type femoroacetabular impingement (40%), anterior inferior iliac spine impingement (subspine) (83%), and mild (borderline) dysplasia (11%). Procedures performed included 95% labral repairs, 5% labral debridements, 99% femoral resections, 49% rim resections, 88% subspine decompressions, and 66% capsular plications. At mean 36 months’ follow-up post-arthroscopy, the mean outcome improvements were 25.6 points (mHHS), 18.9 points (HOOS-activities of daily living), 29.9 points (HOOSSports), 8.7 points (12-Item Short Form Health Survey), and 3.7 points (visual analog scale) (P < .01 for each). Scores were significantly improved from preoperatively to most recent follow-up for mHHS (60.0 vs 85.6 points), HOOS-activities of daily living (72.5 vs 91.5 points), and HOOS-Sports (49.7 vs 79.6) (P < .01). Sixty-three percent of dancers returned to their previous level of competitive dance, 21% returned to limited or modified dance, and 16% were unable to return to dance, including 1 retirement. Conclusions: A careful arthroscopic approach to address cam-type pathomorphology, highly prevalent subspine impingement, and capsular laxity in competitive dancers can achieve a modest rate of return to sport and good-to-excellent patient-reported outcomes at short- to mid-term (3-year) follow-up. Eighty-four percent of dancers ultimately returned to competitive dance, although only 63% returned to their preinjury competitive level. Level of Evidence: IV, case series.
H
ip injuries represent up to 50% of injuries in dancers.1,2 A study evaluating professional ballet dancers reported that 21.6% noted a history of hip problems or injuries that correlated with greater pain scores and lower quality of life scores compared with those without a history of hip problems.3 Motion analysis and magnetic resonance imaging (MRI) studies
in dancers in a splits position have reported significant femoroacetabular impingement (FAI)-induced subluxation even in normal or dysplastic hips, with a predominance of stress at the posterosuperior hip joint proper.4,5 Because of the increased demands placed on the hips secondary to high range of motion requirements, even in the setting of normal or dysplastic
From Twin Cities Orthopedics, Edina, Minnesota (C.M.L., M.R.G., R.S.M., K.N.W.); BocaCare Orthopedics, Deerfield Beach, Florida (J.R.R.); and Department of Orthopedics, University of Michigan MedSport, University of Michigan, Ann Arbor, Michigan (A.B.), U.S.A. The authors report the following potential conflicts of interest or sources of funding: C.M.L. reports personal fees from Smith & Nephew, outside the submitted work; J.R.R. reports personal fees from Smith & Nephew, outside the submitted work; M.R.G. reports personal fees from Ortholink Pty, Ltd., and personal fees from Superior Medical Experts, outside the submitted work; and A.B. reports personal fees and other from Arthrex, outside the submitted
work. Full ICMJE author disclosure forms are available for this article online, as supplementary material. Received April 24, 2019; accepted September 13, 2019. Address correspondence to Christopher M. Larson, M.D., Twin Cities Orthopedics, 4010 West 65th St., Edina, MN 55435. E-mail: chrislarson@tcomn. com Ó 2019 by the Arthroscopy Association of North America 0749-8063/19144/$36.00 https://doi.org/10.1016/j.arthro.2019.09.023
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anatomy, management of these hips is controversial and challenging.6,7 There is very little published literature reporting outcomes after hip arthroscopy in competitive dancers. The purpose of the current study is to report preoperative anatomy, patient-related outcomes measures, and return to dance rates in a cohort of competitive dancers undergoing an arthroscopic hip procedure. The hypothesis was an arthroscopic approach managing the labrum, subspine impingement, and subtle impingementeinduced instability would result in the ability to return to dance, albeit at a level inferior to that historically seen for athletes in other less hipdemanding sports.
Methods Between December 2008 and December 2016, all competitive dancers who underwent hip arthroscopy for hip jointerelated pain by the senior author (C.M.L.) and minimum 1-year follow-up were included for retrospective review. Competitive dance was defined as organized competitive high school, collegiate, dance company, or professional dance (high kick, dance line, or studio dance) that was considered the athletes primary sport. This study was approved by an institutional review board (University of Minnesota: 1308M40962). All patients presented with anterior, groin-related pain with dance activities recalcitrant to physical therapy and activity modification. Impingement testing (flexion, adduction, and internal rotation testing) was positive for all patients and recreated the patients’ presenting complaints. All patients had evidence for a labral tear on MRI. Preoperative imaging for all patients, in addition to MRI, included a standing anteroposterior (AP) pelvis radiograph of both hips, a 45 modified Dunn radiograph and false profile radiograph of the affected hip, and 3-dimensional computed tomographic scans (3DCT) of the affected hip. Patients with arthritic changes (greater than Tönnis 0-1 changes on plain radiographs, MRI bipolar outerbridge changes grade 3-4), inflammatory arthropathy, or radiographically confirmed evidence of osseous hip instability (as defined by femoral head lateralization, extrusion and/or break in Shenton’s line on imaging) were excluded from the study. In general, a Tönnis angle >13 and any femoral head lateralization or migration, and predominance of dysplastic features were considered relative contraindications for hip arthroscopy. Although a specific lateral center edge angle (LCE) was not an absolute exclusion, an LCE below 20 to 25 was a relative contraindication if there was a predominance of instability rather than impingement clinical presentation. Lower LCEs were occasionally considered for hip arthroscopy, as a pelvic osteotomy might lead to some decreased mobility that could be detrimental in this patient population.
Radiographs were assessed with measurements of lateral center edge angle, Tönnis angle, and alpha angle, presence or absence of a cross-over sign (COS), posterior wall sign (PWS), and prominent ischial spine sign. These measurements were performed in a blinded fashion and independently by a fellowship-trained sports medicine hip-preservation surgeon (J.R.R.) to assess acetabular and proximal femur morphology. Patient-reported outcomes measures were obtained preoperatively and postoperatively and included the modified Harris hip score (mHHS), pain on a visual analog scale, 12-Item Short Form Health Survey, and hip disability and osteoarthritis outcomes score (HOOS) (activity of daily living [ADL] and Sports). All physical examinations were performed by the senior author (C.M.L.). The current arthroscopic approach for hip disorders has been previously described by the senior author.8-10 Arthroscopy was performed with the patient in the supine position and procedures performed as indicated, including rim resections for pincer-type FAI, femoral resections for cam-type FAI (lateral alpha angle >50 ) or high range of motion (ROM) femoral neck impingementeinduced subluxation (visualized arthroscopically), anterior inferior iliac spine (AIIS) decompressions for subspine (AIIS) impingement, labral repair versus debridement for labral pathology, chondral debridement and or microfracture for chondral pathology, capsular repair for all hips with additional capsular plications, or shift for associated capsular laxity. The capsule was fully repaired in all cases, but in cases of laxity, the tissue was shifted and overlapped, and in some cases repaired side to side after excision of additional capsule both to increase thickness and eliminate redundancy. This assessment is admittedly subjective but is based on assessment of the available tissue and redundancy observed in the iliofemoral ligament after interportal capsulotomy is completed, with abnormal mobility of the capsule assessed intraoperatively. The capsule was mobilized with a hook to evaluate for excessive redundancy and a shift or plication (excision of additional capsule and side to side repair) on a caseby-case basis. Abnormal motion patterns and high ROM conflicts were assessed preoperatively with dynamic analysis on preoperative planning software (PLAN; Smith & Nephew, Andover, MA) and confirmed intraoperatively by concordant areas of coup and contra-coup injury to the labrum and chondrolabral junction, sclerosis at the distal femoral headeneck junction, ecchymosis in the region of the AIIS, and visualization of levering of the femoral neck at the extremes of hip abduction intraoperatively (Fig 1 A-E). AIIS morphology was classified as Type I-III as defined by Hetsroni et al.11 based on preoperative false-profile radiograph and 3DCT scan images. Distal and
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Fig 1. (A) Modified Dunn lateral radiograph reveals camtype morphology (arrows) with extension of the sclerosis distally to the greater trochanter. (B) Modified Dunn lateral radiograph after femoral resection (arrows) including distal resection to the greater trochanter. (C) Intraoperative image of a left hip reveals capsular ecchymosis indicative of subspine/high range of motion impingement. (D) Intraoperative image of the right hip reveals anterior labral ecchymosis indicative of subspine/high range of motion impingement. (E) 3DCT image of the left hip after dynamic motion analysis reveals impingement between the AIIS and medial femoral neck with high flexion range of motion (blue areas). (3DCT, 3-dimensional computed tomography; AIIS, anterior inferior iliac spine.)
posterolateral femoral and occasionally posterolateral rim resections, subspine (AIIS) decompressions, and capsular management were typically the focus in this patient population. Patients were typically kept toetouch weight bearing postoperatively after arthroscopy for 2 to 3 weeks without a brace or continuous passive motion machine. Physical therapy including early mobilization and ROM with circumduction or well-leg cycling was begun postoperative day 0 or 1.
Return to dance-specific activities began as early as 3 months with full return to dance when pain-free ROM and normal functional progression were achieved at the discretion of a dance-focused physical therapist.
Statistical Analysis Independent samples t tests and paired samples t tests were used where appropriate to determine differences in outcomes scores, with the minimally important
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clinical difference for mHHS and HOOS defined as 10 and 8 points, respectively.12 Univariate regression analyses were used to determine statistical correlations between outcomes and preoperative and postoperative radiographic parameters. c2 analyses were used to determine differences in prevalence rates. Statistical analyses were performed using SPSS v21 (IBM Corp., Armonk, NY). Significance was set at P < .05.
Results Sixty-three competitive dancers (77 hips, 61 female, 2 male) with a mean age 21.2 years (range 13-62 years) were identified between December 2008 and December 2016 and all met the inclusion criteria. Twenty-eight (28) of the 63 athletes (44%) were professional dancers. There were 37 right and 40 left hips. The mean follow-up time was 36 months (range 12-116 months). There were 35 hips (29 dancers) who participated in only studio dance (ballet, jazz, tap, modern, contemporary, lyrical) and 19 hips (14 dancers) who participated in only dance line (high kick). Twenty-two hips (19 dancers) participated in both studio and high kick and 1 hip (1 dancer) did not report the style of dance. Based on plain radiographs and 3DCT imaging, 94.8% of hips (73 hips) had evidence of cam-type FAI (lateral alpha angle >50 13,14). Pincer type FAI (nondysplastic retroversion [LCE >25 ], positive COS, and negative posterior wall sign) was present for 32.5% of hips (25 hips), and profunda (LCE >40 ) was present for 8.1% of hips (6 hips). Subspine impingement was present in 83.1% of hips (64 hips). Borderline (LCE 20 to <25 ) or mild dysplasia (LCE <20 ) was present in only 11% (8 hips) in this case series. Based on preoperative plain radiographic measures (Table 1), the mean LCE was 30.3 (range 16 -44 ), the mean Tönnis angle was 4.2 (range, e4.8 to 14 ), the mean alpha angle was 61.3 (range 40 -90 ) on AP radiographs, and the mean alpha angle was 65.2 (range 45 -84 ) on lateral radiographs. A positive COS was present in 63.6% of hips (49 hips), and a PWS was present in 45.5% of hips (35 hips), indicating acetabular retroversion. No radiographs had femoral head lateralization or extrusion, widening of the medial clear space, and all had continuity of Shenton’s line. Procedures performed included 73 labral repairs (95%), 4 labral debridements (5%), 76 femoral resections (99%) including distal-based resection for high ROM-induced impingement in otherwise-normal alpha angles (73/77 patients had elevated lateral alpha angles), 38 rim resections (49%) including 9 hips (11.7%) undergoing posterior rim resections, 68 subspine decompressions (88%), 51 capsular plications (66%), and 2 psoas tenotomies early in this cohort (3%). In addition, 3 patients had documented EhlerseDanlos syndrome. Psoas tenotomies were not performed later in this series secondary to the risk of hip flexion strength
and active ROM deficits and potential stabilizing role of the psoas tendon in this patient population. One (1%) acetabular microfracture was performed as well as 65 acetabulum chondroplasties (84%) and 1 femoral chondroplasty (1%). At mean 36-month follow-up time, the mean mHHS improved from a preoperative score of 60.02 (range 3198 points) to a most recent score of 85.63 points (range 47-100 points) for a mean overall improvement of 25.61 points (P < .01). The mean HOOS-ADL improved from a preoperative score of 72.52 (range 21-100 points) to a most recent score of 91.47 points (range 53100 points) for a mean overall improvement of 18.95 points (P < .01). The mean HOOS-Sports improved from a preoperative score of 49.73 (range 0-100 points) to a most recent score of 79.57 points (range 25-100 points) for a mean overall improvement of 29.85 points (P < .01). There were also statistically significant overall improvements for 12-Item Short Form Health Survey (8.69 points, P < .01) and visual analog scale scores (3.65 points, P < .01). The majority of dancers achieved minimally important clinical difference for mHHS, HOOS-ADL, and HOOS-Sports (Table 2). There were no statistically significant differences in outcomes based on diagnosis or procedures performed in the cohort (P > .05). Sixty-three percent of dancers returned to their previous level of competitive dance, 21% returned to limited or modified dance, and 16% were unable to return to dance, including 1 retirement. No patients have required conversion to total hip arthroplasty or undergone a revision arthroscopic procedure to date. Standard traction and post-based techniques were used at the time of the study, and there were no tractionrelated complications and specifically no pudendal nerve injuries or perineal soft-tissue injury in any patient. Regarding plain radiographic measures, the mean AP radiograph alpha angle improved from 61.3 (range 40 -90 ) to 47.9 (range 38 -85 ) and the mean lateral radiograph alpha angle improved from 65.2 (range 45 -84 ) to 43.4 (range 35 -83 ). On the acetabular side, a positive COS was present in 63.6% of hips (49 hips) preoperatively compared with 27.3% of hips Table 1. Preoperative and Postoperative Plain Film Radiographic Measurements Radiographic Measurement LCEA Tönnis angle AP alpha angle Lateral alpha angle Prevalence of crossover Prevalence of PWS
Preoperative, Mean 30.3 4.2 61.3 65.2 49/77 35/77
Postoperative, Mean 28.9 4.9 47.9 43.4 21/77 56/77
P Value .004 .001 <.001 <.001 <.001 <.001
AP, anteroposterior; LCEA, lateral center edge angle; PWS, posterior wall sign.
THE DANCER’S HIP Table 2. Preoperative and Postoperative Outcome Scores
PROMs mHHS HOOS-ADL HOOS-Sports VAS SF-12
Preoperative
Postoperative
Mean 60.0 72.5 49.7 6.0 77.2
Mean 85.6 91.5 79.6 2.4 85.6
P Value <.01 <.01 <.01 <.01 <.01
MCID 82.9% 73.5% 76.3% e e
ADL, activities of daily living; HOOS, Hip Disability and Osteoarthritis Outcome Scores; MCID, minimally important clinical difference; mHHS, modified Harris Hip Score; PROMs, patient-reported outcome measures; SF-12, the 12-Item Short Form Health Survey; VAS, visual analog scale.
(21 hips) postoperatively. There were significant changes pre- to postoperatively for the Tönnis angle (P ¼ .001), AP alpha angle (P < .001), and prevalence of a PWS (P < .001). All but 3 hips had 3DCT scans and the mean femoral version was 17.49 (range e8.0 to 38.0). There was no statistically significant relationship between femoral version and return to dance rates (P ¼ .089) and patient-related outcome measures (P ¼ .311).
Discussion A careful arthroscopic approach to address cam-type pathomorphology, prevalent subspine impingement, and capsular laxity in competitive dancers can achieve a high rate of return to sport and good-to-excellent patient-reported outcomes at short- to mid-term followup. In addition, the femoral resection was continued posterolaterally in most cases, and 11.7% of hips underwent posterior rim resections, with posterosuperior FAI being more prevalent in dancers with frequent abduction and external rotation (ER) maneuvers. The current study evaluated a cohort of 63 competitive dancers (77 hips, 28 hips [44%] professional dancers) and demonstrated significant improvements in outcomes (25.61 points MHHS, 18.95 points HOOS-ADL, and 29.85 points HOOS-Sports) and an 84% rate of return to dance (63% preinjury level without modifications) after hip arthroscopy at mean 3-year follow-up. The dancer’s hip in the current study is characterized by subtle FAI with a predominance of mild cam-type morphology, decreased head neck offset (distal based cam) and posterolateral femoral sided impingement, highly prevalent subspine (AIIS) impingement, acetabular retroversion, and capsular laxity. Although dysplasia has been reported to be prevalent in the performing arts and dancers,11 only 11% of the hips in this cohort had dysplastic features and was likely secondary to selection criteria for arthroscopic management. Those with more significant dysplastic features (LCE <20 and Tönnis angle >13 ) generally are not offered an arthroscopic approach in the senior author’s practice.
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There are exceptions when the Tönnis angle was higher and LCE was lower, and the clinical presentation favored impingement rather than instability where arthroscopy was ultimately offered. Although periacetabular osteotomy might be considered with these radiographic parameters for other individuals, this might lead to motion loss that could be detrimental for higher-level dancers. There is very limited outcomes data with regards to hip arthroscopy and performing arts and dance. Hammoud et al.15 reported on 41 professional dancers in New York City. Fifty-five percent of the dancers had dysplastic hips, 25% had FAI, and 22% were reportedly normal.15 Ballet dancers (60% return to dance) and those hips with dysplasia (64% return to dance) were the least likely to return to dance. This is likely secondary to underlying instability not addressed by an arthroscopy and or the extreme hip ROM requirements in this challenging patient population. In addition, the specific procedures performed in this cohort of professional dancers are not clear.15 There has been only one report of 44 hips in dancers undergoing periacetabular osteotomy for more significant hip dysplasia (mean LCE 10.7 , mean Tönnis angle 19.7 ) with a median followup of 2.7 years.16 Although the level of dance or type of dance was not specified, 63% ultimately returned to dance compared with 88% in the current study. The patients undergoing periacetabular osteotomy in that study, however, had a greater degree of dysplasia, as indicated by the lateral center edge angle in comparison with the current study. There was an improvement postoperatively of 17 points (mHHS) and 20 points (HOOS) with a final mHHS of 86.3 points and final HOOS-Sports of 77.3 points at most recent follow-up.16 This is in line with the improvements seen in the current study (improved mHHS 26 points, final mHHS 86 points, improved HOOS-Sports 29.8 points, final HOOS-Sports 79.6 points). Dancers represent a unique group of athletes and performers that requires a high range of motion-based activities.2,6,7,17 Different dancing techniques and styles have different hip joint requirements.2,6,7,17 High-kick dance (dance line), for instance, requires extreme hip flexion for the kick leg and extreme hip extension for the support leg. Ballet hip requirements are more demanding, requiring a combination of extreme hip flexion, extension, abduction, and ballistic movement patterns.2,6,7,17 Previous studies have demonstrated that these high ROM positions (i.e., splits positions) create impingement-induced instability and even subluxation in hips with normal osseous anatomy (absence of FAI or dysplasia).4,5 One study using motion analysis in 11 ballet dancers demonstrated a high frequency of impingement and subluxation with abduction and ER movements seen during developpe a la second, grand ecart facial, grand ecart lateral, and
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grand plié positions.4 The primary zones of impingement were typically superior and posterosuperior.4 It is the current author’s observations during surgery that during extreme hip flexion (high kick), the AIIS (subspine region) contacts the medial distal femoral neck along the medial synovial fold, whereas in extreme hip abduction the acetabular rim contacts the lateral distal femoral neck along the lateral synovial folds. Since normal hips or even dysplastic hips might impinge in extreme hip ROM, the current author believes that distal-based femoral resections along the medial and lateral synovial folds (99% in the current study) in addition to subspine decompressions (83.3% in the current study) and occasionally posterior rim resections (11.7% in the current study) might in part be responsible for the improved outcomes observed in the current study. Femoral version might also have implications regarding the ROM profile of the hip. Extreme lower-extremity ER is required to achieve turn-out. It might be advantageous to have increased femoral retroversion to achieve greater degrees of lower-extremity ER. Studies are somewhat contradictory with regards to this topic. One study in ballet dancers showed similar measures of femoral version versus non-dancing controls,18 whereas another study demonstrated greater degrees of femoral retroversion in ballet dancers who underwent >6 hours of ballet a week between the ages of 11 and 14 years, possibly indicating an effect of ballet on the developing physis not unlike proximal humeral retroversion seen in throwing athletes.19 In the current study, a number of dance styles and techniques were observed as opposed to strictly ballet, but the overall femoral version of 17.5 (normal reportedly around 10 ) was not consistent with relative femoral retroversion in this patient population. The approach for management of these hyperflexible, extreme ROM, subtle FAI hips has arisen from experience in this population and continues to evolve. Subtle distal-based femoral resections medially and laterally and AIIS decompressions are performed to increase the impingement and subluxation-free hip ROM. Labral repair is performed which, in addition to providing a seal, might provide a degree of stability in these hips with soft-tissue laxity and or dysplastic variants. The capsule is carefully evaluated and repair in every case with plications or shifts reserved for excessive capsular laxity and incompetence to potentially increase stability. Care should be taken to avoid overtensioning the capsule, which could result in loss of ER and subsequent turnout and could be detrimental to a competitive dancer. No patients in the current study experienced ER loss, and care was taken to close, shift, or plicate the capsule with the hip near full extension and ER to prevent loss of ER or turnout in this patient population.
Limitations Limitations for the current study include the retrospective design and all of the associated bias and limitations. Three years is not long-term follow-up and with the high demands placed on the hips by these performers, and longer-term follow-up is critical from an outcomes and sustained return to play and performing standpoint. In addition, management of these subtle deformities, dysplastic variants, and soft-tissue laxity cases are evolving rapidly, and the management of these cases over the 5-year study period may have differed based on this evolution. Although only 11% of the cases had evidence for dysplastic features, there is a selection bias for those potentially benefiting from arthroscopic management rather than being representative for all competitive dancers or performing artists in general. Correspondingly, the variable and individualized nature of the surgical intervention is a challenge to objectify and a limitation. Therefore, the current outcomes should not be generalized to all dancers where radiographic dysplasia and potential clinical instability has shown to predominate from a morphologic standpoint. Although competitive dancing athletes almost certainly demonstrate some hyperlaxity, Beighton scores were not formally assessed in this population, and we cannot comment regarding this potentially important topic. Finally, there is some variability in the procedures that are performed for each individual patient as well as the variability of levels of dancing, thus making generalizability more difficult.
Conclusions A careful arthroscopic approach to address camtype pathomorphology, highly prevalent subspine impingement, and capsular laxity in competitive dancers can achieve a modest rate of return to sport and good-to-excellent patient-reported outcomes at short to mid-term (3 years) follow-up. Eighty-four percent of dancers ultimately returned to competitive dance, although only 63% returned to their preinjury competitive level.
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THE DANCER’S HIP 5. Duthon VB, Charbonnier C, Kolo FC, et al. Correlation of clinical and magnetic resonance imaging findings in hips of elite female ballet dancers. Arthroscopy 2013;29: 411-419. 6. Weber AE, Bedi A, Tibor LM, Zaltz I, Larson CM. The hyperflexible hip: Managing hip pain in the dancer and gymnast. Sports Health 2015;7:346-358. 7. Hamilton WG, Hamilton LH, Marshall P, Molnar M. A profile of the musculoskeletal characteristics of elite professional ballet dancers. Am J Sports Med 1992;20: 267-273. 8. Larson CM. Arthroscopic management of hip pathomorphology. Instr Course Lect 2012;61:287-293. 9. Larson CM, Giveans MR. Arthroscopic management of femoroacetabular impingement: Early outcomes measures. Arthroscopy 2008;24:540-546. 10. Larson CM, Giveans MR. Arthroscopic debridement versus refixation of the acetabular labrum associated with femoroacetabular impingement. Arthroscopy 2009;25: 369-376. 11. Hetsroni I, Poultsides L, Bedi A, Larson CM, Kelly BT. Anterior inferior iliac spine morphology correlates with hip range of motion: A classification system and dynamic model. Clin Orthop Relat Res 2013;471:2497-2503. 12. Harris JD, Brand JC, Cote MP, Faucett SC, Dhawan A. Research pearls: The significance of statistics and perils of pooling. Part 1: Clinical versus statistical significance. Arthroscopy 2017;33:1102-1112.
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13. Beaule PE, LeDuff M, Zaragoza EJ. Quality of life following femoral head-neck osteochondroplasty for femoroacetabular impingement. J Bone Joint Surg Am 2007;89:773-779. 14. Tannast M, Siebenrock KA, Anderson S. Femoroacetabular impingement: Radiographic diagnosisdwhat the radiologist should know. AJR Am J Roentgenol 2007;188:1540-1552. 15. Hammoud S, Brown HC, Kelly BT, Padgett DE. Hip Arthroscopy in the Professional Dancer. San Diego, CA: Paper presented at the 2011 Annual Meeting of the American Academy of Orthopaedic Surgeons, February 15-19, 2011. 16. Novais EN, Thanacharoenpanich S, Seker A, et al. Do young female dancers improve symptoms and return to dancing after periacetabular osteotomy for the treatment of symptomatic hip dysplasia? J Hip Preserv Surg 2018;5: 150-156. 17. Kushner S, Saboe L, Reid D, Penrose T, Grace M. Relationship of turnout to hip abduction in professional ballet dancers. Am J Sports Med 1990;18:286-291. 18. Bauman PA, Singson R, Hamilton WB. Femoral neck anteversion in ballerinas. Clin Orthop Relat Res 1994: 57-63. 19. Hamilton D, Aronsen P, Løken JH, et al. Dance training intensity at 11-14 years is associated with femoral torsion in classical ballet dancers. Br J Sports Med 2006;40: 299-303. discussion 303.