Brayden J. Gerrie

Microinstability of the hip and the splits radiograph

A normal hip has a natural tendency toward stability because of both osseous and soft tissue structures. Hip motion is primarily rotational around a center of rotation. When the femoral head and its center of rotation translate, with or without rotation, the inherent stability of the femoroacetabular articulation may be lost. The spectrum of hip instability ranges from subtle microinstability to traumatic dislocation. Microinstability may be the cause or the effect of several other hip pathologies. Soft tissue contributions to stability include the static capsule, dynamic musculotendinous units, and underlying generalized connective tissue (eg, Ehlers-Danlos). Osseous contributions include multiple femoral and acetabular radiographic coverage parameters. Iatrogenic contributions include an unrepaired capsulotomy, overresection of the acetabular rim (iatrogenic dysplasia), overresection of cam osteochondroplasty, iliopsoas tenotomy, labral debridement, and ligamentum teres debridement. Patients with hip microinstability often have deep groin pain, exhibited by a C sign. These patients frequently participate in flexibility sports and activities, such as ballet, gymnastics, figure skating, and martial arts. On physical examination, generalized hypermobility syndromes should be assessed, as should loss of log-roll external rotation recoil, excessive abduction, trochanteric-pelvic impingement, and abductor fatigue. Standard imaging, including plain radiographs, magnetic resonance imaging, and computed tomography, should be analyzed for all causes of hip pain. A new plain radiograph, the splits radiograph is introduced here, consistently showing lateral femoral head translation and creation of a vacuum sign, showing hip microinstability. The splits radiograph is illustrated in a 22-year-old female dancer who presented with bilateral deep anterolateral groin pain.

Radiographic Prevalence of Dysplasia, Cam, and Pincer Deformities in Elite Ballet

Background: The demands of hip strength and motion in ballet are high. Hip disorders, such as cam and pincer deformities or dysplasia, may affect dance performance. However, the prevalence of these radiographic findings is unknown. Purpose: To determine the prevalence of radiographic cam and pincer deformities, borderline dysplasia, and dysplasia in a professional ballet company. Study Design: Cross-sectional study; Level of evidence, 3. Methods: An institutional review board–approved cross-sectional investigation of a professional ballet company was undertaken. Male and female adult dancers were eligible for inclusion. Four plain radiographs were obtained (standing anteroposterior pelvis, bilateral false profile, and supine Dunn 45°) and verified for adequacy. Cam and pincer deformities, dysplasia, borderline dysplasia, and osteoarthritis were defined. All plain radiographic parameters were measured and analyzed on available radiographs. Student t test, chi-square test (and Fisher exact test), and Spearman correlation analyses were performed to compare sexes, groups, and the effect of select radiographic criteria. Results: A total of 47 dancers were analyzed (21 males, 26 females; mean age (±SD), 23.8 ± 5.4 years). Cam deformity was identified in 25.5% (24/94) of hips and 31.9% (15/47) of subjects, with a significantly greater prevalence in male dancers than females (48% hips and 57% subjects vs 8% hips and 12% subjects; P < .001 and P = .001, respectively). Seventy-four percent of subjects had at least 2 of 6 radiographic signs of pincer deformity. Male dancers had a significantly greater prevalence of both prominent ischial spine and posterior wall signs (P = .001 and P < .001, respectively), while female dancers had a significantly greater prevalence of coxa profunda (85% female hips vs 26% male hips; P < .001). Eighty-nine percent of subjects had dysplasia or borderline dysplasia in at least 1 hip (37% dysplastic), with a significantly greater prevalence of dysplasia or borderline dysplasia in female versus male dancers (92% female hips vs 74% male hips; P < .022). Further, in those with dysplasia or borderline dysplasia, 92% of female and 82% of male dancers had bilateral findings. Conclusion: In this professional ballet company, a high prevalence of radiographic abnormalities was found, including cam and pincer deformity and dysplasia. The results also revealed several sex-related differences of these abnormalities in this unique population. The long-term implications of these findings in this group of elite athletes remain unknown, and this issue warrants future investigation.

Incidence and Prevalence of Musculoskeletal Injury in Ballet: A Systematic Review

Background Most published studies on injuries in the ballet dancer focus on the lower extremity. The rigors of this activity require special training and care. By understanding prevalence and injury pattern to the musculoskeletal system, targeted prevention and treatment for this population can be developed. Purpose To determine the incidence and prevalence of musculoskeletal injuries in ballet. Study Design Systematic review; Level of evidence, 4. Methods A systematic review registered with PROSPERO was performed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Level 1 through 4 evidence studies reporting incidence of musculoskeletal injuries in male and female ballet dancers were included, with the numbers and types of injuries extracted from each. Injury rates were recorded and calculated based on professional status, sex, and nature of injury. Incidence was defined as number of injuries sustained over a specific time. Prevalence was defined as proportion of subjects with an injury at a given point in time. Results The studies analyzed reported injury incidence or prevalence in more than 1365 amateur and 900 professional dancers. The mean age was 16.2 years among amateur and 27.0 years among professional dancers. The incidence of injury among amateur dancers was 0.99 and 1.09 injuries per 1000 dance hours in males and females, respectively; 75% of injuries were overuse, with similar rates among males and females. In professional dancers, the incidence of injury was 1.06 and 1.46 injuries per 1000 dance hours in males and females, respectively, and 64% of female injuries were overuse, compared with 50% in males (P < .001). Only 3 studies provided prevalence data, including 62% prevalence of lumbosacral pain, 58% painful snapping hip, and 29% patellofemoral pain. Lower extremity injuries comprised 66% to 91% of all injuries, with the foot and ankle accounting for 14% to 57%. Conclusion The overall incidence of injury among amateur and professional ballet dancers is 0.97 and 1.24 injuries per 1000 dance hours, respectively. The majority are overuse in both amateur and professional dancers, with amateur ballet dancers showing a higher proportion of overuse injuries than professionals (P < .001). Male professional dancers show a higher proportion of traumatic injuries, accounting for half of their injuries (P < .001).

Arthroscopic hip preservation surgery practice patterns: an international survey

Abstract To design and conduct a survey analyzing pre-, intra- and post- hip arthroscopy practice patterns among hip arthroscopists worldwide. A 21-question, IRB-exempt, HIPAA-compliant, cross-sectional survey was conducted via email using SurveyMonkey to examine pre-operative evaluation, intra-operative techniques and post-operative management. The survey was administered internationally to 151 hip arthroscopists identified from publicly available sources. Seventy-five respondents completed the survey (151 ± 116 hip arthroscopy procedures per year; 8.6 ± 7.1 years hip arthroscopy experience). Standing AP pelvis, false profile and Dunn 45 were the most common radiographs utilized. CT scans were utilized by 54% of surgeons at least some of the time. Only 56% of participants recommended an arthrogram with MRI. Nearly all surgeons either never (40%) or infrequently (58%) performed arthroscopy in Tönnis grade-2 or grade-3 osteoarthritis. Surgeons rarely performed hip arthroscopy on patients with dysplasia (51% never; 44% infrequently). Only 25% of participants perform a routine ‘T’ capsulotomy and 41% close the capsule if the patient is at risk for post-operative instability. Post-operatively, 52% never use a brace, 39% never use a continuous passive motion, 11% never recommended heterotopic ossification prophylaxis and 30% never recommended formal thromboembolic disease prophylaxis. Among a large number of high-volume experienced hip arthroscopists worldwide, pre-, intra- and post- hip arthroscopy practice patterns have been established and reported. Within this cohort of respondents, several areas of patient evaluation and management remain discordant and controversial without universal agreement. Future research should move beyond expert opinion level V evidence towards high-quality appropriately designed and conducted investigations.

Dorsal Defect of the Patella in a Teenage Male Football Player: A Case Report and Differential Diagnosis of Lytic Patellar Lesion

Dorsal defect of the patella (DDP) is a well-documented yet infrequently observed osteolytic lesion on the superolateral aspect of the patella, primarily occurring in the second and third decades of life.§ The plain radiographic appearance of DDP is typically a round radiolucent lesion with a peripheral sclerotic margin. On a magnetic resonance imaging (MRI) fluid-sensitive series, DDP is demonstrated as a hyperintense focal contour abnormality. Often asymptomatic, DDP is frequently discovered as an incidental finding in up to 75% of cases.5,9,13,15,17,18 This often occurs when investigating etiologies of symptomatic differential diagnoses, such as osteochondritis dissecans, meniscal tears, ligamentous injury, chondromalacia, and patellar instability.1,3,5,7,11,13,15,19

Lower thoracic rib stress fractures in baseball pitchers.

Abstract Stress fractures of the first rib on the dominant throwing side are well-described in baseball pitchers; however, lower thoracic rib fractures are not commonly recognized. While common in other sports such as rowing, there is scant literature on these injuries in baseball. Intercostal muscle strains are commonly diagnosed in baseball pitchers and have a nearly identical presentation but also a highly variable healing time. The diagnosis of a rib stress fracture can predict a more protracted recovery. This case series presents two collegiate baseball pitchers on one team during the same season who were originally diagnosed with intercostal muscle strains, which following magnetic resonance imaging (MRI) were found to have actually sustained lower thoracic rib stress fractures. The first sustained a stress fracture of the posterior aspect of the right 8th rib on the dominant arm side, while the second presented with a left-sided 10th rib stress fracture on the nondominant arm side. In both cases, MRI was used to visualize the fractures as plain radiographs are insensitive and commonly negative early in patient presentation. Patients were treated with activity modification, and symptomatic management for 4–6 weeks with a graduated return to throwing and competition by 8–10 weeks. The repetitive high stresses incurred by pitching may cause either dominant or nondominant rib stress fractures and this should be included in the differential diagnosis of thoracic injuries in throwers. It is especially important that athletic trainers and team physicians consider this diagnosis, as rib fractures may have a protracted course and delayed return to play. Additionally, using the appropriate imaging techniques to establish an accurate diagnosis can help inform return-to-play decisions, which have important practical applications in baseball, such as roster management and eligibility.

Although the injury rate of yoga is low, nearly two-thirds of musculoskeletal injuries in yoga affect the lower extremity: a systematic review

Importance Yoga is a very popular sporting activity across the world. There is limited information on the epidemiology and characteristics of yoga-related injuries. Objective To determine the incidence and prevalence of musculoskeletal injuries sustained in yoga. Evidence review A systematic review was registered with PROSPERO and performed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and checklist. Level I–IV evidence studies reporting the incidence and prevalence of musculoskeletal injuries in male and female yoga practitioners were eligible for inclusion. The number and types of injuries were extracted from each study. Duplicate patient populations within separate distinct publications were analysed and reported only once. Injury rates were recorded and calculated on the basis of gender and nature of injury. Incidence was defined as the number of injuries sustained over a specific time duration. Prevalence was defined as the proportion of subjects with an injury at a given point in time. Findings Five studies were analysed that reported injury incidence or prevalence in yoga (7453 subjects). In four of these studies, the type of yoga was not specified, but Mikkonen et al focused solely on Ashtanga Vinyasa practitioners. There were 6544 female (88%) and 909 male (12%) yoga practitioners analysed (49.1±13.6 years of age). The incidence of injury among yoga practitioners was 1.18 injuries per 1000 yoga hours. Only four studies provided prevalence data, displaying 6.6% injury prevalence in 7415 yoga practitioners overall (up to 62% in Ashtanga Vinyasa). Overall, lower extremity injuries comprised 64% of total injuries; specifically the hip, hamstring, knee, ankle, feet and toe. The upper extremity and head and trunk injuries account for 13% and 23%, respectively. Conclusions and relevance There is limited quantity heterogeneous evidence reporting the characteristics of yoga injuries. The overall injury incidence is 1.18 injuries per 1000 yoga hours. The prevalence of injury is poorly characterised. However, the weighted mean prevalence is 7%. The majority of yoga injuries are lower extremity injuries. Level of evidence Level IV, a systematic review of level I–IV studies.

Comparison of MRI, CT, Dunn 45° and Dunn 90° alpha angle measurements in femoroacetabular impingement

Purpose: To determine if a significant difference existed among alpha angle measurements between 4 imaging techniques, axial oblique CT and MRI, Dunn 45° and Dunn 90° plain radiographs, in patients with symptomatic cam femoroacetabular impingement (FAI) and labral tear. Methods: A single-surgeon prospective radiographic analysis of consecutive non-arthritic and non-dysplastic -patients with symptomatic FAI and labral tears who underwent surgery was performed. Alpha angle was measured using standard techniques as described by Nötzli. Cam morphology was defined via alpha angle measurement of >50.5 degrees. Group comparisons were made using ANOVA and chi-squared test. Sample size calculation was performed prior to study enrollment. Results: 31 subjects (16 female; 33.5 ± 10.5 years mean age) were included. There was a significant difference in alpha angle measurements between all 4 imaging techniques (F [3,120] = 8.144; p<0.001), with the Dunn 45° view (66.3 ± 11.4°) significantly greater than all 3 other techniques (Dunn 90° [57.5 ± 10.7°; p = 0.015], MRI [53.3 ± 11.5°; p<0.001], and CT (54.9 ± 11.6°; p = 0.001). There was no significant difference in alpha angle between Dunn 90°, MRI, and CT. There was a significant difference in the observed number of hips with cam morphology between imaging techniques (χ2 9.4; p = 0.025). Conclusions: The Dunn 45° radiograph yielded a significantly higher alpha angle than Dunn 90°, axial oblique MRI, and CT imaging modalities. Use of the Dunn 90° or axial oblique MRI or CT as the threshold for cam osteoplasty may result in untreated symptomatic cam FAI. The authors recommend the Dunn 45° radiograph as the most sensitive evaluation of cam morphology.

Patient Reported Outcomes and Symptomatic Impingement in US Women’s Professional Soccer

Objectives: The purpose of this study was to determine: 1) normative data of multiple general health-, activity-, hip and groin-, and depression-specific patient-reported outcome (PRO) questionnaires; 2) if any PRO’s were able to predict a positive anterior impingement test, in female professional soccer player. Methods: An IRB-approved cross-sectional investigation of adult female US professional soccer players was performed at the team pre-season physical examination day. Adult (>18 years of age) female players without prior hip surgery were eligible. Hip impingement physical examination was performed (anterior, subspine, lateral, posterior) and recorded. Multiple questionnaires were administered to each player, including Short-Form-12 (Mental Component and Physical Component Scores [MCS, PCS]), Tegner activity score, Non-Arthritic Hip Score (NAHS), Hip and Groin Outcome Score (HAGOS), international Hip Outcome Tool-12 (iHOT-12), and Zung Depression Index. Descriptive statistics were calculated. Kolmogorov-Smirnov analysis was performed for data normality and Pearson’s (parametric) or Spearman’s (non-parametric) to assess correlation of ROM and radiographs. Binary logistic regression was performed to ascertain the effects of each PRO questionnaire score and prediction of a positive anterior impingement test. Results: Twenty-four players (48 hips) were analyzed (25.4+/-3.0 years of age; 2.8+/-2.2 years professional experience). Scores were collected: Tegner 9.9+/-0.3; SF-12 PCS 52.9+/-7.4; SF-12 MCS 54.3+/-7.0; iHOT-12 96.6+/-5.4%; NAHS Total 97.9+/-4.9; HAGOS symptoms 90.5+/-10.5, pain 97.8+/-3.4, activities of daily living 99.4+/-2.2, sports 97.1+/-4.2, physical activity 97.9+/-7.1, and quality of life 95.8+/-8.7; Zung 27.6+/-5.9. The iHOT-12 was able to correctly predict 71% of cases of positive anterior impingement test for the left hip and the logistic regression model was statistically significant, (5.2)1, p=0.02. For the right hip, the iHOT-12 was able to correctly predict 79% of cases of positive anterior impingement and the logistic regression model was statistically significant, χ 2 (9.1)1, p=0.003. SF-12 MCS and PCS scores were able to correctly predict 83% of cases for the left hip and the logistic regression model was statistically significant, χ 2 (11)2, p=0.005. The Zung score was able to correctly predict 83% of cases for the left hip and the logistic regression model was statistically significant, χ 2 (4.1)1, p=0.04. Conclusion: Multiple general health-, activity-, hip and groin-, and depression-specific patient reported outcome scores were collected and normative data established in a US women’s professional soccer club, showing that iHOT-12, SF-12 MCS and PCS, and Zung depression scores were able to correctly predict symptomatic impingement.

Is digital photography an accurate and precise method for measuring range of motion of the hip and knee

BackgroundAccurate measurements of knee and hip motion are required for management of musculoskeletal pathology. The purpose of this investigation was to compare three techniques for measuring motion at the hip and knee. The authors hypothesized that digital photography would be equivalent in accuracy and show higher precision compared to the other two techniques.MethodsUsing infrared motion capture analysis as the reference standard, hip flexion/abduction/internal rotation/external rotation and knee flexion/extension were measured using visual estimation, goniometry, and photography on 10 fresh frozen cadavers. These measurements were performed by three physical therapists and three orthopaedic surgeons. Accuracy was defined by the difference from the reference standard, while precision was defined by the proportion of measurements within either 5° or 10°. Analysis of variance (ANOVA), t-tests, and chi-squared tests were used.ResultsAlthough two statistically significant differences were found in measurement accuracy between the three techniques, neither of these differences met clinical significance (difference of 1.4° for hip abduction and 1.7° for the knee extension). Precision of measurements was significantly higher for digital photography than: (i) visual estimation for hip abduction and knee extension, and (ii) goniometry for knee extension only.ConclusionsThere was no clinically significant difference in measurement accuracy between the three techniques for hip and knee motion. Digital photography only showed higher precision for two joint motions (hip abduction and knee extension). Overall digital photography shows equivalent accuracy and near-equivalent precision to visual estimation and goniometry.