Hip Joint Effusion-Synovitis Is Associated With Hip Pain and Sports/Recreation Function in Female Professional Ballet Dancers.

OBJECTIVE: To compare hip joint effusion-synovitis prevalence in professional ballet dancers with nondancing athletes and to evaluate the relationship between effusion-synovitis and clinical measures and cartilage defects. DESIGN: Case-control study. SETTING: Elite ballet and sport. PARTICIPANTS: Forty-nine professional ballet dancers and 49 age-matched and sex-matched athletes. INDEPENDENT VARIABLES: Group (dancers/athletes), sex, age, years of training, Copenhagen Hip and Groin Outcome Scores (HAGOSs), hip rotation range of motion (ROM), generalized joint hypermobility (GJH), and hip cartilage defect scores. MAIN OUTCOME MEASURES: Hip joint effusion-synovitis (absent, grade 1 = 2-4 mm, grade 2 = >4 mm) scored with 3-Tesla magnetic resonance imaging. RESULTS: Hip joint effusion-synovitis was found in 22 (45%) dancers and 13 (26.5%) athletes (P = 0.06). Grade 2 effusion-synovitis was only found in dancers (n = 8, r = 0.31, P = 0.009). The prevalence of effusion-synovitis was similar in men (n = 11, 26%) and women (n = 24, 43%, P = 0.09). Female dancers with effusion-synovitis had lower HAGOS pain (r = 0.63, P = 0.001) and sports/recreation scores (r = 0.66, P = 0.001) compared with those without effusion-synovitis. The HAGOS scores were not related to effusion-synovitis in male dancers or female and male athletes (P > 0.01 for all). Effusion-synovitis was not related to hip ROM, GJH, or cartilage defect scores (P > 0.05 for all). CONCLUSIONS: Hip joint effusion-synovitis was related to higher levels of pain and lower sports/recreation function in female ballet dancers. Effusion-synovitis was not related to hip rotation ROM, GJH or cartilage defects. Larger sized joint effusion-synovitis was exclusively found in dancers.

Bony morphology of the hip in professional ballet dancers compared to athletes.

OBJECTIVES: To compare hip bony morphology between ballet dancers and a sporting control group and to determine the relationship with hip pain. METHODS: Thirty-three professional ballet dancers and 33 age- and sex-matched athletes completed questionnaires, including the Copenhagen Hip and Groin Outcome Score (HAGOS), and underwent clinical testing and 3.0-T magnetic resonance imaging to measure acetabular coverage with lateral centre edge angles, femoral head-neck junction concavity with alpha angles at anterior and superior positions, femoral neck-shaft angles, and acetabular version angles. RESULTS: Bony morphological measures fell within normal ranges. Dancers had higher neck-shaft angles (dancers 134.6 ± 4.6°/athletes130.8 ± 4.7°, p = 0.002), lower acetabular version angles (13.5 ± 4.7°/17.1 ± 4.7°, p = 0.003), lower superior alpha angles (38.9 ± 6.9°/46.7 ± 10.6°, p < 0.001), similar anterior alpha angles (43.6 ± 8.1/46 ± 7°, p = 0.2), and similar lateral centre edge angles (28.8 ± 4.6°/30.8 ± 4.5°, p = 0.07) compared to athletes. Abnormal morphology was detected in dancers: 3% acetabular dysplasia (athletes 0), 15% borderline dysplasia (6%), 24% cam morphology (33%), 24% coxa valga (6%), and 21% acetabular retroversion (18%). The HAGOS pain scores correlated moderately with acetabular version (r = -0.43, p = 0.02) in dancers, with no other correlation between pain and morphological parameters in either group. CONCLUSIONS: Professional ballet dancers have hip bony morphology that differentiates them from athletes. Hip pain correlated poorly with bony morphology. KEY POINTS: • Ballet dancers have hip bony morphology that may allow extreme hip motion. • Morphological parameter means fell within normal reference intervals in dancers. • Bony morphology correlates poorly with hip pain. • The risk of hip injury due to abnormal morphology requires prospective studies.

Atraumatic tears of the ligamentum teres are more frequent in professional ballet dancers than a sporting population.

OBJECTIVES: To compare the frequency of atraumatic ligamentum teres (LT) tear in professional ballet dancers with that of athletes, and to determine the relationship with clinical and imaging findings. METHODS: Forty-nine male and female professional ballet dancers (98 hips) and 49 age and sex-matched non-dancing athletes (98 hips) completed questionnaires on hip symptoms and physical activity levels, underwent hip rotation range of movement (ROM) and hypermobility testing, and 3.0-Tesla magnetic resonance imaging (3 T MRI) on both hips to detect LT tears, acetabular labral tears, and articular cartilage defects, and to measure the lateral centre edge angles (LCE). RESULTS: A higher frequency of LT tear was found in dancers (55 %) compared with athletes (22 %, P = 0.001). The frequency and severity of LT tears in dancers increased with older age (P = 0.004, P = 0.006, respectively). The Hip and Groin Outcome Score (HAGOS) pain scores or hip rotation ROM did not differ significantly among participants with normal, partial, or complete tears of LT (P > 0.01 for all). Neither the frequency of generalised joint hypermobility (P = 0.09) nor the LCE angles (P = 0.32, P = 0.16, left and right hips respectively) differed between those with and those without LT tear. In most hips, LT tear co-existed with either a labral tear or a cartilage defect, or both. CONCLUSION: The higher frequency of atraumatic LT tears in professional ballet dancers suggests that the LT might be abnormally loaded in ballet, and caution is required when evaluating MRI, as LT tears may be asymptomatic. A longitudinal study of this cohort is required to determine if LT tear predisposes the hip joint to osteoarthritis.

Similar Prevalence of Acetabular Labral Tear in Professional Ballet Dancers and Sporting Participants.

OBJECTIVE: To compare the prevalence of acetabular labral tear in male and female professional ballet dancers with age-matched and sex-matched sporting participants and to determine the relationship to clinical findings and cartilage defects. DESIGN: Case-control study. SETTING: Clinical and radiology practices. PARTICIPANTS: Forty-nine (98 hips) male and female professional ballet dancers (current and retired) with median age 30 years (range: 19-64 years) and 49 (98 hips) age-matched and sex-matched sporting participants. INDEPENDENT VARIABLES: Group (ballet or sports), sex, age, hip cartilage defects, history of hip pain, Hip and Groin Outcome Score, passive hip internal rotation (IR), and external rotation range of movement (ROM). MAIN OUTCOME MEASURES: Labral tear identified with 3T magnetic resonance imaging (MRI). RESULTS: Labral tears were identified in 51% of all 196 hips. The prevalence did not differ significantly between the ballet and sporting participants (P = 0.41) or between sexes (P = 0.34). Labral tear was not significantly associated with clinical measures, such as pain and function scores or rotation ROM (P > 0.01 for all). Pain provocation test using IR at 90° of hip flexion had excellent specificity [96%, 95% confidence intervals (CIs), 0.77%-0.998%] but poor sensitivity (50%, 95% CI, 0.26%-0.74%) for identifying labral tear in participants reporting hip pain. Older age and cartilage defect presence were independently associated with an increased risk of labral tear (both P < 0.001). CONCLUSIONS: The prevalence of labral tear in male and female professional ballet dancers was similar to a sporting population. Labral tears were not associated with clinical findings but were related to cartilage defects, independent of aging. CLINICAL RELEVANCE: Caution is required when interpreting MRI findings as labral tear may not be the source of the ballet dancer's symptoms.

Hip flexor muscle size in ballet dancers compared to athletes, and relationship to hip pain.

OBJECTIVES: To compare hip flexor muscle cross-sectional area (CSA) in ballet dancers and athletes, and to evaluate the relationship between hip flexor size and hip pain. STUDY DESIGN: Case control study. SETTING: Elite ballet and sport. PARTICIPANTS: 33 professional ballet dancers and 33 age and sex-matched athletes. MAIN OUTCOME MEASURES: CSA's of hip flexor muscles iliopsoas, rectus femoris, sartorius and tensor fascia latae (TFL) on magnetic resonance imaging (MRI) of one hip. Hip pain was scored with the Copenhagen Hip and Groin Outcome Score (HAGOS): HAGOS pain score of 100 was defined as no pain and a score less than 100 was defined as pain. Participants' weight and height. RESULTS: Dancers had larger iliopsoas (P < 0.001, ηp2 = 0.25), TFL (P = 0.001, ηp2 = 0.17), and sartorius (P < 0.001, ηp2 = 0.18) estimated marginal mean muscle CSAs compared to athletes. Rectus femoris muscle size did not differ between groups (P = 0.095, ηp2 = 0.04). Iliopsoas estimated marginal mean muscle CSA was 8% smaller in participants with hip pain compared to those with no hip pain (P = 0.035, ηp2 = 0.7). There was no interaction between the estimated marginal mean muscle CSA of rectus femoris, TFL and sartorius and pain. CONCLUSION: Ballet appears to selectively load iliopsoas, TFL and sartorius muscles but not rectus femoris. Iliopsoas muscle size was smaller in participants with hip pain, but TFL, sartorius and rectus femoris muscle size was not related to hip pain.

Obturator externus was larger, while obturator internus size was similar in ballet dancers compared to nondancing athletes.

OBJECTIVES: To compare the cross-sectional area (CSA) of hip external rotators, obturator externus (OE) and obturator internus (OI), in ballet dancers and nondancing athletes, and evaluate the relationship between obturator muscle size and hip pain. DESIGN: Case-control study. SETTING: Elite ballet and sport. PARTICIPANTS: 33 male and female professional ballet dancers and 33 age and sex-matched athletes. MAIN OUTCOME MEASURES: CSA's of OE and OI measured on magnetic resonance imaging (MRI) of one hip. Hip pain was scored with the Copenhagen Hip and Groin Outcome Score (HAGOS): HAGOS pain score of 100 was defined as no pain and a score less than 100 was defined as pain. Participants weight and height. RESULTS: Estimated marginal mean CSA of OE was 14% larger in dancers than athletes (p = 0.01, ηp2 = 0.1); the size of OI was similar (p > 0.05). Men and women in both groups had similar sized OI and OE. There was no interaction between the estimated marginal mean CSA of either obturator and hip pain. CONCLUSIONS: It appears that ballet selectively increases muscle size of OE, but not OI. Obturator size was not related to mild hip pain, as OE and OI size was similar in dancers and athletes with and without pain.

Professional ballet dancers have a similar prevalence of articular cartilage defects compared to age- and sex-matched non-dancing athletes.

Ballet exposes the hip joint to repetitive loading in extreme ranges of movement and may predispose a dancer to pain and osteoarthritis (OA). The aims of this study were to compare the prevalence of cartilage defects in professional ballet dancers and athletes and to determine the relationship of clinical signs and symptoms. Forty-nine male and female, current and retired professional ballet dancers and 49 age- and sex-matched non-dancing athletes completed hip pain questionnaires, including the Copenhagen Hip and Groin Outcome Score (HAGOS), and underwent hip range of movement (ROM) testing and 3-Tesla magnetic resonance imaging to score cartilage defects (no defect, grade 1: focal partial defect and grade 2: diffuse or full thickness defect). Thirty (61 %) dancers and 27 (55 %) athletes had cartilage defects (p = 0.54). The frequency of grade 1 and 2 cartilage defects did not differ between dancers and athletes (p = 0.83). The frequency of cartilage defects was similar in male and female dancers (p = 0.34), and male and female athletes (p = 0.24). Cartilage defects were not related to history of hip pain (p = 0.34), HAGOS pain (p = 0.14), sports/rec (p = 0.15) scores or hip internal rotation ≤20° (p > 0.01). Cartilage defects were related to age in male dancers (p = 0.002). Ballet dancers do not appear to be at a greater risk of cartilage injury compared to non-dancing athletes. Male dancers develop cartilage defects at an earlier age than athletes and female dancers. Cartilage defects were not related to clinical signs and symptoms; thus, prospective studies are required to determine which cartilage defects progress to symptomatic hip OA.