Descriptive Epidemiology From the Research in Osteochondritis Dissecans of the Knee (ROCK) Prospective Cohort.

BACKGROUND: Osteochondritis dissecans (OCD) occurs most commonly in the knees of young individuals. This condition is known to cause pain and discomfort in the knee and can lead to disability and early knee osteoarthritis. The cause is not well understood, and treatment plans are not well delineated. The Research in Osteochondritis Dissecans of the Knee (ROCK) group established a multicenter, prospective cohort to better understand this disease. PURPOSE: To provide a baseline report of the ROCK multicenter prospective cohort and present a descriptive analysis of baseline data for patient characteristics, lesion characteristics, and clinical findings of the first 1000 cases enrolled into the prospective cohort. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Patients were recruited from centers throughout the United States. Baseline data were obtained for patient characteristics, sports participation, patient-reported measures of functional capabilities and limitations, physical examination, diagnostic imaging results, and initial treatment plan. Descriptive statistics were completed for all outcomes of interest. RESULTS: As of November 2020, a total of 27 orthopaedic surgeons from 17 institutions had enrolled 1004 knees with OCD, representing 903 patients (68.9% males; median age, 13.1 years; range, 6.3-25.4 years), into the prospective cohort. Lesions were located on the medial femoral condyle (66.2%), lateral femoral condyle (18.1%), trochlea (9.5%), patella (6.0%), and tibial plateau (0.2%). Most cases involved multisport athletes (68.1%), with the most common primary sport being basketball for males (27.3% of cases) and soccer for females (27.6% of cases). The median Pediatric International Knee Documentation Committee (Pedi-IKCD) score was 59.9 (IQR, 45.6-73.9), and the median Pediatric Functional Activity Brief Scale (Pedi-FABS) score was 21.0 (IQR, 5.0-28.0). Initial treatments were surgical intervention (55.4%) and activity restriction (44.0%). When surgery was performed, surgeons deemed the lesion to be stable at intraoperative assessment in 48.1% of cases. CONCLUSION: The multicenter ROCK group has been able to enroll the largest knee OCD cohort to date. This information is being used to further understand the pathology of OCD, including its cause, associated comorbidities, and initial presentation and symptoms. The cohort having been established is now being followed longitudinally to better define and elucidate the best treatment algorithms based on these presenting signs and symptoms.

Can EOS Imaging Substitute for Conventional Radiography in Measurement of Acetabular Morphology in the Young Dysplastic Hip?

BACKGROUND: EOS imaging offers a low-radiation alternative to conventional radiography (CR) and has little to no magnification effects. However, it is unclear how radiographic measures may be affected using EOS. The present study aims to determine the reproducibility of measures of acetabular morphology on EOS images as compared with CR, and to directly compare the 2 imaging modalities. METHODS: A total of 21 consecutive patients (66.7% female; 14.4±4.7 y) indicated for an open hip preservation procedure with both an anterior-posterior pelvis radiograph and EOS image performed preoperatively were included. Three orthopaedic surgeons measured Tönnis angle, lateral center edge angle (LCEA), acetabular depth-width ratio (ADR), and extrusion index (EI). Measurements were performed twice, 2 weeks apart. Reliability between observers and time points was measured using intraclass correlation coefficients, and agreement between time points and modalities was measured using Bland-Altman analysis. RESULTS: On EOS images, inter-rater reliability was 0.86 for Tönnis angle, 0.86 for LCEA, 0.74 for ADR, and 0.93 for EI. On CR, inter-rater reliability was 0.86 for Tönnis anlge, 0.90 for LCEA, 0.82 for ADR, and 0.84 for EI. In the agreement analysis, biases between imaging modalities were observed. On average, raters measured Tönnis angle and EI higher on EOS images than CR (2.22 degrees, 1.09%, respectively); and LCEA and ADR lower on EOS images than CR (1.54 degrees, 1.14% respectively). Limits of agreement (LOA) between modalities were similar to that of LOA observed in intra-rater analysis. CONCLUSIONS: Measures of acetabular morphology performed on EOS images have similarly high intra-rater and inter-rater reliability compared with CR. Measures performed on EOS also have similar intra-rater agreement as compared with CR. Intermodality agreement had similar LOA as intra-rater agreement on either individual imaging modality. Small biases between imaging modalities were detected. LEVELS OF EVIDENCE: Level I-diagnostic study: investigating a diagnostic test.

Reliability of the classification of cartilage and labral injuries during hip arthroscopy.

To determine interobserver and intraobserver reliabilities of the combination of classification systems, including the Beck and acetabular labral articular disruption (ALAD) systems for transition zone cartilage, the Outerbridge system for acetabular and femoral head cartilage, and the Beck system for labral tears. Additionally, we sought to determine interobserver and intraobserver agreements in the location of injury to labrum and cartilage. Three fellowship trained surgeons reviewed 30 standardized videos of the central compartment with one surgeon re-evaluating the videos. Labral pathology, transition zone cartilage and acetabular cartilage were classified using the Beck, Beck and ALAD systems, and Outerbridge system, respectively. The location of labral tears and transition zone cartilage injury was assessed using a clock face system, and acetabular cartilage injury using a five-zone system. Intra- and interobserver reliabilities are reported as Gwet's agreement coefficients. Interobserver and intraobserver agreement on the location of acetabular cartilage lesions was highest in superior and anterior zones (0.814-0.914). Outerbridge interobserver and intraobserver agreement was >0.90 in most zones of the acetabular cartilage. Interobserver and intraobserver agreement on location of transition zone lesions was 0.844-0.944. The Beck and ALAD classifications showed similar interobserver and intraobserver agreement for transition zone cartilage injury. The Beck classification of labral tears was 0.745 and 0.562 for interobserver and intraobserver agreements, respectively. The Outerbridge classification had almost perfect interobserver and intraobserver agreement in classifying chondral injury of the true acetabular cartilage and femoral head. The Beck and ALAD classifications both showed moderate to substantial interobserver and intraobserver reliabilities for transition zone cartilage injury. The Beck system for classification of labral tears showed substantial agreement among observers and moderate intraobserver agreement. Interobserver agreement on location of labral tears was highest in the region where most tears occur and became lower at the anterior and posterior extents of this region. The available classification systems can be used for documentation regarding intra-articular pathology. However, continued development of a concise and highly reproducible classification system would improve communication.

Gradual Deformity Correction in Blount Disease.

BACKGROUND: Blount disease is a disorder of the posteromedial proximal tibial physis which causes a progressive varus, procurvatum, and internal rotation deformity of the tibia. Untreated, it can cause significant limb malalignment. The goal of this study is to evaluate the results of correction of Blount disease using types of external fixation. METHODS: We conducted a retrospective review of 41 patients (51 limbs) who underwent correction of Blount disease with an Ilizarov external fixator or a Taylor spatial frame (TSF) by a single surgeon. The medial proximal tibial angle (MPTA), mean axis deviation (MAD), posterior proximal tibial angle, and joint line congruence angle (JLCA) were measured on radiographs preoperatively, at frame removal and at final follow-up. RESULTS: The average age at treatment was 9.6 years old, with a mean follow-up time of 34 months. Mean preoperative MPTA, MAD, and JLCA were significantly improved at the time of frame removal as well as at final follow-up with no significant changes in correction between the time of frame removal and final follow-up. There was no difference in MPTA and MAD in patients treated with an Ilizarov frame versus a TSF. MPTA, MAD, and JLCA all significantly improved regardless of the underlying diagnosis (infantile vs. adolescent Blount disease) or history of prior surgical intervention. The most common complication was superficial pin-site infection. CONCLUSIONS: Both Iliazarov and TSF are viable treatment options for infantile and adolescent Blount disease, with the ability to significantly improve both the limb mechanical axis and the mechanical axis of the affected tibia. Correction can be attained regardless of whether patients have previously failed surgical intervention. LEVEL OF EVIDENCE: Level III-retrospective comparative study.

Simultaneous Bilateral Hip Arthroscopy in Adolescent Athletes With Symptomatic Femoroacetabular Impingement.

BACKGROUND: Femoroacetabular impingement represents a common cause of hip pain in adolescents. The purpose of the present study was to evaluate the safety and efficacy of simultaneous bilateral hip arthroscopy for bilateral symptomatic femoroacetabular impingement in adolescent athletes. METHODS: Clinical data were collected in a prospective database on patients who underwent unilateral or simultaneous bilateral hip arthroscopy and included complications, reoperation rate, and return to play time. Differences in International Hip Outcome Tool (iHOT)-12 scores according to hip side and postoperative follow-up time (preoperative, 1.5, 3, 6, 12, and 24 mo) were evaluated using a 2×6 repeated-measures analysis of variance with post hoc repeated-measures 1-way analysis of variance and Bonferroni-corrected paired t tests. RESULTS: In total, 24 patients (36 hips) were studied, of whom 12 underwent simultaneous bilateral hip arthroscopy (24 hips) and a case-matched control group of 12 patients underwent unilateral hip arthroscopy. There were 5 males in each group (41.7%). Average age was 15.7 and 16.5 years in the bilateral and unilateral groups, respectively. No patients were lost to follow-up. In the bilateral group, a significant increase in mean iHOT-12 score was observed between 1.5- and 3-month follow-up (61.8 vs. 82.8, respectively; P=0.003), and 6-, 12-, and 24-month follow-up (91.4, 95.1, and 96.6, respectively, P=0.004). At all follow-up times, there were no significant differences in mean iHOT-12 scores or other outcome measures between bilateral and unilateral cohorts. Time to return to preinjury level of activity was similar between the bilateral and unilateral groups (4.7 vs. 4.9 mo, respectively; P=0.40). One transient lateral femoral cutaneous nerve palsy occurred in each group, though no other complications were documented. No patients required revision surgery by latest follow-up. CONCLUSIONS: Bilateral simultaneous hip arthroscopy is safe and reproducible in adolescent athletes, achieving equivalent outcomes, and similar rehabilitation time when compared with unilateral surgery. LEVEL OF EVIDENCE: Level II-therapeutic study.

High Body Mass Index is Related to Increased Perioperative Complications After Periacetabular Osteotomy.

The purpose of this study is to determine the relationship of body mass index (BMI), age, smoking status, and other comorbid conditions to the rate and type of complications occurring in the perioperative period following periacetabular osteotomy. A retrospective review was performed on 80 hips to determine demographic information as well as pre- and postoperative pain scores, center-edge angle, Tönnis angle, intraoperative blood loss, and perioperative complications within 90 days of surgery. Patients were placed into high- (>30) and low- (<30) BMI groups to determine any correlation between complications and BMI. The high-BMI group had a significantly greater rate of perioperative complications than the low-BMI group (30% vs 8%) and, correspondingly, patients with complications had significantly higher BMI than those without (30.9 ± 9.5, 26.2 ± 5.6) (P = .03). Center-edge angle and Tönnis angle were corrected in both groups. Improvement in postoperative pain scores and radiographically measured acetabular correction can be achieved in high- and low-BMI patients. High-BMI patients have a higher rate of perioperative wound complications.

What Are the Effects of Capsular Plication on Translational Laxity of the Glenohumeral Joint: A Study in Cadaveric Shoulders.

BACKGROUND: Surgical treatment for shoulder instability generally involves labral repair with a capsular plication or imbrication. Good results are reported in both open and arthroscopic procedures, but there is no consensus on the amount or location of capsular plication that is needed to achieve stability and anatomic anterior, posterior, and inferior translation of the joint. QUESTIONS/PURPOSES: (1) What are the separate and combined effects of increasing plication magnitude and sequential additive plications in the anterior, posterior, and inferior locations of the joint capsule on glenohumeral joint translation in the anterior, posterior, and inferior directions? (2) What plication location and magnitude restores anterior, posterior, and inferior translation to a baseline level? METHODS: Fourteen cadaveric shoulders were dissected down to the glenohumeral capsule and underwent instrumented biomechanical testing. Each shoulder was loaded with 22 N in anterior, posterior, and inferior directions at 60° abduction and neutral rotation and flexion and the resulting translation were recorded. Testing was done over baseline (native), stretched (mechanically stretched capsule to imitate a lax capsule), and 5-mm, 10-mm, and 15-mm plication conditions. Individually, for each of the 5-, 10-, and 15-mm increments, plications were done in a fixed sequential order starting with anterior plication at the 3 o'clock position (Sequence I), then adding posterior plication at the 9 o'clock position (Sequence II), and then adding inferior plication at the 6 o'clock position (Sequence III). Each individual sequence was tested by placing 44 N (10 pounds) of manual force on the humerus directed in an anterior, posterior, and inferior direction to simulate clinical load and shift testing. The effect of plication magnitude and sequence on translation was tested with generalized estimating equation models. Translational differences between conditions were tested with paired t-tests. RESULTS: Translational laxity was highest with creation of the lax condition, as expected. Increasing plication magnitude had a significant effect on all three directions of translation. Plication location sequence had a significant effect on anterior and posterior translation. An interaction effect between plication magnitude and sequence was significant in anterior and posterior translation. Laxity in all directions was most restricted with 15-mm plication in anterior, posterior, and inferior locations. For anterior translational laxity, at 10-mm and 15-mm plication, there was a progressive decrease in translation magnitude (10-mm plication anterior only: 0.46 mm, plus posterior: 0.29 mm, plus inferior, -0.12 mm; and for 15-mm anterior only: -0.53 mm, plus posterior: -1.00 mm, plus inferior: -1.66 mm). For posterior translational laxity, 10-mm and 15-mm plication also showed progressive decrease in magnitude (10-mm plication anterior only: 0.46 mm, plus posterior: -0.25 mm, plus inferior: -1.94; and for 15-mm anterior only: 0.14 mm, plus posterior: -1.54 mm, plus inferior: -3.66). For inferior translational laxity, tightening was observed only with magnitude of plication (anterior only at 5 mm: 0.31 mm, at 10 mm: -1.39, at 15 mm: -3.61) but not with additional plication points (adding posterior and inferior sequences). To restore laxity closest to baseline, 10-mm AP/inferior plication best restored anterior translation, 15-mm anterior plication best restored posterior translation, and 5 mm posterior with or without inferior plication best restored inferior translation. CONCLUSIONS: Our results suggest that (1) a 10-mm plication in the anterior and posterior or anterior, posterior, and inferior positions may restore anterior translation closest to baseline; (2) 10-mm anterior and posterior or 15-mm anterior plications may restore posterior translation closest to baseline; and (3) 5-mm anterior and posterior or anterior, posterior, and inferior plications may restore inferior translation closest to baseline. Future studies using arthroscopic techniques for plication or open techniques via a true surgical approach might further characterize the effect of plication on glenohumeral translation. CLINICAL RELEVANCE: This study found that specific combinations of plication magnitude and location can be used to restore glenohumeral translation from a lax capsular state to a native state. This information can be used to guide surgical technique based on an individual patient's degree and direction of capsular laxity. In vivo testing of glenohumeral translation before and after capsular plication will be needed to validate these cadaveric results.

Mapping glenohumeral laxity: effect of capsule tension and abduction in cadaveric shoulders.

BACKGROUND: Shoulder capsular plication aims to restore the passive stabilization of the glenohumeral capsule; however, high reported recurrence rates warrant concern. Improving our understanding of the clinical laxity assessment across 2 dimensions, capsular integrity and shoulder position, can help toward the standardization of clinical tools. Our objectives were to test and describe glenohumeral laxity across 5 capsular tension levels and 4 humeral position levels and describe tension-position interplay. METHODS: We tested 14 dissected cadavers for glenohumeral laxity in 5 directions: anterior, posterior, and inferior translation, and internal and external axial rotation. Laxity was recorded across capsule tension (baseline, stretched, 5 mm, 10 mm, and 15 mm of plication) and position (0°, 20°, 40°, 60° of scapular abduction). Repeated-measures analysis of variance with post hoc contrasts tested the effect of tension, position, and composite tension × position on laxity. RESULTS: Capsule tension, position, and composite interplay had a statistically significant, although unequal, effect on laxity in each direction. Laxity was consistently overconstrained in 15-mm plication and was overall greatest in 20° and lowest in 60°. Restoration occurred most in 10 mm, but this depended on the position. The composite effect was significant for external and internal rotation and inferior laxity, but laxity at the middle range (20° or 40°) was different than at the end range (0° or 60°) for all directions. CONCLUSIONS: On average, laxity was restored to baseline tension after 10-mm plication, but this determination varied depending on shoulder position. Middle-range laxity behaved differently than end-range laxity across plication tensions. This information is useful in understanding the unstable shoulder as well as for standardizing clinical laxity assessment.

The Epidemiology and Effect of Sliding Injuries in Major and Minor League Baseball Players.

BACKGROUND: Although sliding occurs frequently in professional baseball, little is known about the epidemiology and effect of injuries that occur during sliding in this population of elite athletes. PURPOSE: To describe the incidence and characteristics of sliding injuries, determine their effect in terms of time out of play, and identify common injury patterns that may represent appropriate targets for injury prevention programs in the future. STUDY DESIGN: Descriptive epidemiologic study. METHODS: All offensive sliding injuries occurring in Major League Baseball (MLB) and Minor League Baseball (MLB) that resulted in time out of play during a span of 5 seasons (2011-2015) were identified. In addition to player demographics, data extracted included time out of play, location on field where injury occurred, level of play, treatment (surgical vs nonsurgical), direction of slide (head vs feet first), body region injured, and diagnosis. Descriptive statistics were used to describe the distribution of these injuries, and injury rates were calculated per slide. RESULTS: From 2011 to 2015, 1633 injuries occurred as a result of a slide. The total number of days missed per season was 4263. Surgical intervention was required for 134 (8.2%) injuries, and the mean days missed was 66.5 for players treated surgically and 12.3 days for players treated nonoperatively ( P < .001). MLB players were more likely than MiLB players to require surgical intervention (12.3% vs 7.5%, P = .019). Injuries to the hands/fingers represented 25.3% of all injuries and 31.3% of those requiring surgery. Although the majority of injuries occurred at second base (57%), the per-slide injury rate was similar across all bases ( P = .991). The estimated overall frequency of injury in MLB was once per every 336 slides, and the rate of injury for head- and feet-first slides was 1 in 249 and 413 slides, respectively ( P = .119). CONCLUSION: Injuries occurring while sliding in professional baseball result in a significant amount of time out of play for these elite athletes. Injuries occurring at second base and those occurring to the hands and fingers were most prevalent and may be an appropriate target for future injury prevention programs.

Functional Outcomes and Cam Recurrence After Arthroscopic Treatment of Femoroacetabular Impingement in Adolescents.

PURPOSE: To compare the functional outcomes after arthroscopic treatment of femoroacetabular impingement (FAI) in adolescent patients and non-adolescent patients, and to report on the rate of cam recurrence within 2 years after femoral osteoplasty in a limited sample of the adolescent group. METHODS: From 2010 to 2014, patients younger than 18 years with symptomatic FAI (alpha angle >50°) who underwent hip arthroscopy with minimum 2-year follow-up or reoperation were identified. A group of non-adolescent patients with identical inclusion criteria, except age of 18 years or older, was also identified for comparison. In addition, a separate group of adolescent patients with 2-year postoperative radiographs was reviewed for cam recurrence. Demographic data, operative data, and radiographic and clinical outcomes (modified Harris Hip Score [mHHS], Hip Outcome Score-Activities of Daily Living [HOS-ADL], Hip Outcome Score-Sport-Specific Subscale [HOS-SSS], and International Hip Outcome Tool 33 [iHOT-33] score) were collected. RESULTS: We identified 34 adolescent patients (38 hips) with an average age of 16 years (range, 13-17 years). The mean clinical follow-up period was 36.1 ± 11.6 months (range, 24.1-71.7 months) and 29.6 ± 2.4 months (range, 27.9-31.3 months) without and with reoperation, respectively. A control group of 296 non-adolescent patients (306 hips), with a mean age of 31 years (range, 18-59 years), was identified as our non-adolescent group. The mean clinical follow-up period was 34.1 ± 11 months (range, 24.0-77.4 months) and 15.1 ± 9.1 months (range, 3.6-34.6 months) without and with reoperation, respectively. Significant improvement was noted in adolescents in the changes in outcome scores (mHHS, 22.2 [95% confidence interval (CI), 15.4-29.0]; HOS-ADL, 18.6 [95% CI, 11.9-25.2]; HOS-SSS, 33.5 [95% CI, 24.5-42.5]; and iHOT-33 score, 30.5 [95% CI, 21.8-39.2]; P < .001). Similar improvements were observed in non-adolescents (mHHS, 21.0 [95% CI, 19.0-23.0]; HOS-ADL, 16.6 [95% CI, 14.6-18.6]; HOS-SSS, 30.1 [95% CI, 26.6-33.6]; and iHOT-33 score, 34.9 [95% CI, 31.5-38.3]; P < .001). There was no evidence of a difference in follow-up survey scores between groups (P > .203). Revision surgery was required in 2 adolescent hips (5.3% [95% CI, 1.5%-17.3%]) and 19 non-adolescent hips (6.2% [95% CI, 4.0%-9.5%]). Minimum 2-year radiographs were available for review in 24 adolescent patients (30 hips). The alpha angle (mean ± standard deviation) was reduced from 55.4° ± 12.1° preoperatively to 38.7° ± 4.9° at 6 weeks postoperatively (mean difference, -16.4° [95% CI, -19.8° to -12.9°]; P < .001). At 2 years, the alpha angle remained at 39.2° ± 11.2°, which did not differ from 6-week measurements (mean difference, 0.5° [95% CI, -2.9° to 3.9°]; P = .784). There were no cases of cam recurrence (0% [95% CI, 0%-11.4%]). CONCLUSIONS: Significant improvement in clinical outcomes can be anticipated after arthroscopic treatment of FAI in adolescents. From a limited sample of our adolescent population, the risk of cam recurrence appears low; however, further follow-up is needed to ensure this does not represent a biased sample of the initial population. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Safety of Hip Anchor Insertion From the Midanterior and Distal Anterolateral Portals With a Straight Drill Guide: A Cadaveric Study.

BACKGROUND: During arthroscopic labral refixation, suture anchors are typically inserted from either the midanterior (MA) portal or the distal anterolateral (DALA) portal; however, no studies have previously compared these techniques. Purpose/Hypothesis: The purpose of this study was to compare acetabular rim accessibility and associated complication rates of anchor insertion from these portals. We hypothesized that rim access would be better from the DALA portal. Additionally, we hypothesized that articular surface perforation would occur more commonly from the MA portal while psoas tunnel perforation would occur more commonly from the DALA portal. STUDY DESIGN: Controlled laboratory study. METHODS: Sixteen pelvic cadaveric specimens (32 hips) were obtained and arthroscopic surgery performed in the supine position. Suture anchors were placed at 7 predetermined locations (9-, 11-, 12-, 1-, 2-, 3-, and 4-o'clock positions). Hips were treated as matched pairs, such that one hip from each specimen had all anchors placed from the MA portal and the other from the DALA portal. Allocation ensured an equal distribution of laterality between groups. After anchor insertion, specimens underwent computed tomography and dissection for further evaluation. RESULTS: Rim accessibility was similar between the groups; anchor insertion was most difficult at the 9-o'clock position, particularly with the MA portal technique, where only 50% (8/16) of attempts were successful, in comparison to the DALA portal technique, where 75% (12/16) of attempts were successful. Additionally, the 4-o'clock position proved challenging to access with the DALA portal technique, where only 75% (12/16) of attempts were successful, compared with 100% with the MA portal technique. The difference in accessibility of these techniques, however, did not reach statistical significance at the 9-o'clock position ( P = .2734) or 4-o'clock position ( P = .1012). Articular surface perforation occurred in 4.48% of all anchor insertion attempts, most commonly at the 3-o'clock position ( P = .0242). From the MA portal, 4.00% (4/100) perforated the joint, compared with 4.95% (5/101) from the DALA portal ( P > .999). Further, there were no significant differences in perforation rates at each location between the techniques ( P > .999). Psoas tunnel perforation occurred in 7.69% of all anchor insertion attempts between 2 and 4 o'clock, with equal rates at each location ( P ≥ .6606). From the MA portal, 4.17% (2/48) perforated the psoas tunnel, compared with 11.63% (5/43) from the DALA portal ( P ≥ .2486). Further, there were no significant differences at each location between the techniques ( P ≥ .4839). There was no association between acetabular version, femoral version, or lateral center-edge angle (LCEA) and articular surface or psoas tunnel perforation, regardless of portal use. CONCLUSION: Anchor insertion from either the MA or DALA portal appears to confer similar rim access and rates of articular surface or psoas tunnel perforation, with a cumulative rate of 4.48% and 7.69%, respectively. Rates of perforation did not differ between the portals and were not associated with acetabular or femoral version or LCEA. CLINICAL RELEVANCE: Caution should be employed when inserting anchors for labral refixation, particularly in anterior and medial locations (2-4 o'clock), as articular surface and psoas tunnel perforation may occur at a rate higher than previously anticipated. Portal selection does not appear to influence these outcomes.

Return to Play Following Open Treatment of Femoroacetabular Impingement in Adolescent Athletes.

INTRODUCTION: After treatment of femoroacetabular impingement (FAI) in adolescent competitive athletes, the rate, timing, and level of return to play have not been well reported. METHODS: Adolescent athletes who underwent open FAI treatment were assessed at a minimum 1-year follow-up. Patients completed a self-reported questionnaire centered on the time and level of return to play. Pain and functional outcomes were assessed using the modified Harris Hip Score (mHHS) and the Hip Disability and Osteoarthritis Outcome Score (HOOS). RESULTS: Among the 24 athletes included, 21 (87.5%) (95% confidence interval [CI], 67.6% to 97.3%) successfully returned to play after open FAI treatment. The median time to return to play was 7 months (95% CI, 6 to 10 months). Of the 21 who returned to play, 19 (90%) returned at a level that was equivalent to or greater than their level of play before surgery. Three athletes (12.5%) did not return to play and indicated that failure to return to play was unrelated to their hip. There was significant improvement in the mHHS (P < 0.0001), HOOS (P < 0.0001), α angle (P < 0.0001), and offset (P < 0.0001). DISCUSSION: Most adolescent athletes can expect to return to the same or better level of sports participation during the first year after open treatment of FAI.

Patient Characteristics and Early Functional Outcomes of Combined Arthroscopic Labral Refixation and Periacetabular Osteotomy for Symptomatic Acetabular Dysplasia.

BACKGROUND: Symptomatic labral tears are common in patients with acetabular dysplasia; however, optimal treatment of the labrum remains controversial. PURPOSE: To present patient characteristics and early functional outcomes associated with combined arthroscopic labral refixation and Bernese periacetabular osteotomy (PAO) for symptomatic acetabular dysplasia with a displaced labral tear from the acetabular rim. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Patients undergoing PAO from a single-center prospective hip preservation registry were eligible (N = 73 patients; mean clinical follow-up, 23 months). Indications for combined arthroscopic labral refixation included symptomatic labral injury and MRI findings suggestive of labral detachment from the acetabular rim indicating a repairable tear. The study group consisted of patients undergoing combined arthroscopic labral refixation and PAO (scope/PAO group: n = 21 patients). Patients undergoing PAO alone (PAO group: n = 52 patients) were included as a comparison. Demographic characteristics, pre- and postoperative radiographic findings, and hip-specific functional outcome scores were recorded. RESULTS: The scope/PAO group was older relative to PAO alone (27 vs 23 years; P = .047). Preoperative computed tomography showed increased acetabular version at the 3-o'clock position in the scope/PAO group relative to PAO alone (median [quartile 1, quartile 3]: 24° [20°, 25°] vs 19° [14°, 24°]; P = .026). PAO operative time, achievement of radiographic correction, or postoperative complications did not differ between groups. Improvements by minimum important change for modified Harris Hip Score, Hip Outcome Score (HOS)-ADL, HOS-Sport, and International Hip Outcome Tool (iHOT-33) were seen in 90%, 79%, 74%, and 100% of patients, respectively, undergoing scope/PAO at most recent follow-up. There was greater improvement from baseline in the iHOT-33 at most recent follow-up in the scope/PAO versus PAO group after adjusting for age and Tönnis grade (mean change ± SD: 48 ± 22 [scope/PAO] vs 37 ± 24 [PAO]; P = .03). CONCLUSION: Patients undergoing combined arthroscopic labral refixation and PAO were older and had increased acetabular anteversion versus patients undergoing PAO alone. Combined arthroscopic labral refixation and PAO was safe, did not affect PAO operative time or radiographic correction achievement, and may benefit clinical outcomes in this patient subset.

Femoroacetabular Impingement Is Associated With Sports-Related Posterior Hip Instability in Adolescents: A Matched-Cohort Study.

BACKGROUND: Femoroacetabular impingement (FAI) deformity has been associated with posterior hip instability in adult athletes. PURPOSE: To determine if FAI deformity is associated with posterior hip instability in adolescents, the femoral head-neck junction or acetabular structure in a cohort of adolescent patients who sustained a low-energy, sports-related posterior hip dislocation was compared with that in a group of healthy age- and sex-matched controls with no history of hip injury or pain. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: We identified 12 male patients (mean age, 13.9 years; range, 12-16 years) who sustained a sports-related posterior hip dislocation and underwent a computed tomography (CT) scan after closed reduction. For each patient, 3 age- and sex-matched healthy controls were identified. Femoral head-neck type was assessed by measurement of the alpha angle on the radially oriented CT images at the 12-, 1-, 2-, and 3-o'clock positions. Age, body mass index (BMI), alpha angle at each position, acetabular version, Tönnis angle, and lateral center-edge angle (LCEA) on the involved hip in the dislocation group were compared with those of the matched controls using a mixed-effects model. A logistic regression analysis using a generalized estimating equation was used to compare the percentage of subjects with cam-type FAI deformity (alpha angle >55°) in each group. RESULTS: The dislocation and control groups were similar in age distribution and BMI (P > .05). The mean alpha angles were statistically significantly higher in the dislocation group compared with the control group at the superior (46.3° ± 1.1° vs 42.7° ± 0.6°; P = .0213), superior-anterior (55.5° ± 1.9° vs 46.0° ± 1.3°; P = .0005), and anterior-superior (54.9° ± 1.5° vs 48.9° ± 1.0°; P = .0045) regions. Cam deformity was present in a larger proportion of patients in the dislocation group than in the control group (P < .0035). An alpha angle greater than 55° was present in 16.7% of the dislocation group and 0% of the control group at the 12-o'clock position (P = .1213), 41.7% versus 0% at the 1-o'clock position (P = .0034), 58% versus 6% at the 2-o'clock position (P = .0004), and 25% versus 2.8% at the 3-o'clock position (P = .0929). Acetabular anteversion was lower in the dislocation group (9.6° ± 1.4°) compared with the control group (15.1° ± 0.8°) (P = .0068). Mean acetabular LCEA was within a normal range in both groups. CONCLUSION: A significantly higher mean alpha angle from the superior to the anterior-superior regions of the femoral head-neck junction and lower acetabular version were found in adolescents who sustained low-energy, sports-related posterior hip dislocations.

The Epidemiology of Hip and Groin Injuries in Professional Baseball Players.

Injuries of the hip and groin among professional baseball players can result in a significant number of disabled list days. The epidemiology of these injuries has not been delineated. The purpose of this study is to describe the incidence, mechanism, type, and rehabilitation course of hip and groin injuries among Major League Baseball (MLB) and Minor League Baseball (MiLB) players. The MLB injury database for hip and groin injuries from 2011-2014 was analyzed. Occurrence of injuries was assessed based on level of play, field location, activity during which the injury occurred, mechanism of injury, and days missed. The treatment was recorded as nonoperative or surgical. The subsequent rehabilitation and return to play were recorded. Chi-square tests were used to test the hypothesis of equal proportions between the various categories of hip and groin characteristics. From 2011-2014, 1823 hip and groin injuries occurred among MLB and MiLB players, which accounted for approximately 5% of all injuries. Of these, 1514 (83%) occurred among MiLB players and 309 (17%) among MLB players; 96% of injuries were extra-articular. Among all players, a noncontact mechanism during defensive fielding was the most common activity causing injury (74%), and infielders experienced the most hip and groin injuries (34%). The majority of extra-articular injuries were treated nonoperatively (96.2%), resulting in an average of 12 days missed. Intra-articular pathology more commonly required surgery, and resulted in an average of 123 days missed. Hip and groin injuries can be debilitating and result in a significant number of days missed. Intra-articular pathology and athletic pubalgia were usually treated surgically, while the majority of extra-articular hip injuries were treated successfully with nonoperative modalities. Correct diagnosis and appropriate treatment can lead to a high rate of return to play for professional baseball players with injuries to the hip and groin.

Surgical Hip Dislocation for the Treatment of Intra-Articular Injuries and Hip Instability Following Traumatic Posterior Dislocation in Children and Adolescents.

BACKGROUND: Traumatic posterior hip dislocation in children is a rare injury that typically is treated with closed reduction. Surgical treatment is typically recommended for nonconcentric reduction with joint space asymmetry with entrapped labrum or an osteochondral fragment. The surgical hip dislocation (SHD) approach allows for full assessment of the acetabulum and femoral head and has been our preferred surgical strategy. The purpose of this study was to (1) describe the intra-articular pathologic findings seen at the time of SHD; and (2) to investigate hip pain, function, and activity level of a cohort of children and adolescents after open treatment of a posterior hip dislocation using the SHD approach. METHODS: Following IRB approval, 23 patients who sustained a traumatic posterior hip dislocation between January 2009 and December 2013 were identified. In 8/23 (34.8%) patients there was evidence of nonconcentric reduction after closed treatment and surgical treatment was performed using the SHD approach. Seven male and 1 female (mean age, 11.2 y; range, 6 to 14.6 y) were followed for an average of 28 months (range, 13 to 67 mo). The modified Harris Hip Score (mHHS) and the University of California Los Angeles activity score assessed clinical hip outcome and activity level at minimum of 1 year after surgery. RESULTS: Six patients were treated after an acute trauma, whereas 2 were treated after recurrent dislocations. Five patients were involved in motor vehicle accidents and 3 in sports-related injuries. Intraoperative findings include posterior labral avulsion in all patients, fracture of the cartilaginous posterior wall (n=3), and femoral head chondral injuries (n=5) and fracture (n=1). The labral root was repaired using suture anchor technique in 7/8 patients and resected in 1. In 2 patients, labral repair was complemented by screw fixation of the posterior wall. All but one patient (mHHS=94) reported maximum mHHS. The University of California Los Angeles activity score was 10 for 5/8 patients and 7 in 3 patients. No case of femoral head osteonecrosis was noted. One patient developed an asymptomatic heterotopic ossification. CONCLUSIONS: When open reduction is recommended for the treatment of intra-articular pathologies and hip instability following traumatic dislocation of the hip in children and adolescents, the SHD is an excellent approach that allows surgical correction of the damaged bony and soft-tissue structures including repair of the capsule-labral complex, and reduction and internal fixation of the cartilaginous posterior wall and femoral head fractures. LEVEL OF EVIDENCE: Level IV.

MRI as a reliable and accurate method for assessment of posterior hip dislocation in children and adolescents without the risk of radiation exposure.

BACKGROUND: Posterior hip dislocation in children and adolescents may involve the non-ossified posterior acetabular wall. Plain radiographs and computed tomography (CT) have been shown to underestimate injury to the unossified acetabulum as well as associated soft-tissue structures. OBJECTIVE: The purpose of this study was to describe findings on radiographs, CT and magnetic resonance imaging (MRI) after posterior hip dislocation in a series of adolescents and to report the intraoperative findings, which are considered the gold standard. Measurements of the posterior wall length using MRI and CT scans were also performed. MATERIAL AND METHODS: After institutional review board approval, 40 patients who sustained a traumatic posterior dislocation of the hip between September 2007 and April 2014 were identified. Inclusion criteria were (1) age younger than 16 years old and (2) availability of MRI obtained following closed reduction of the hip. Eight male patients and one female patient with an average age of 13.2 years (range: 10.1-16.2 years) underwent hip MRI following posterior dislocation. Seven of the nine patients also underwent evaluation by CT. Plain radiographs, CT scans and MRI were evaluated in all patients by a single pediatric radiologist blinded to surgical findings for joint space asymmetry, posterior wall fracture, femoral head fracture, labrum tear, complete or partial ligamentum teres rupture and presence of intra-articular fragments. Six patients underwent surgical treatment and the intraoperative findings were compared with the imaging findings. RESULTS: CT identified all bone injuries but underestimated the involvement of posterior wall fractures. Assessment of the posterior wall size and fracture displacement was possible with MRI. All surgically confirmed soft-tissue injuries, including avulsion of the posterior labrum, were identified preoperatively on MRI. The measurement of posterior wall length was not statistically different using CT and MRI. CONCLUSION: Intraoperative pathological findings at the time of open surgical treatment were universally recognized on MRI but not on CT scans. MRI should be considered for evaluation of the hip following closed reduction for the treatment of a posterior dislocation in children and adolescents as it reliably allows assessment of intra-articular pathology without the risk of radiation exposure.

The influence of thumb metacarpophalangeal joint rotation on the evaluation of ulnar collateral ligament injuries: a biomechanical study in a cadaver model.

PURPOSE: To determine whether variation in thumb metacarpophalangeal (MCP) joint pronosupination influences perceived ulnar collateral ligament (UCL) stability during clinical stress testing. METHODS: Twelve fresh-frozen specimens underwent sequential evaluation for the following conditions: ligament intact (LI), proper UCL deficient (-pUCL), and proper and accessory UCL deficient (UCL). Valgus stress testing was completed in both 0° and 30° MCP joint flexion for thumb pronation, neutral, and supination. RESULTS: Compared with neutral MCP joint rotation, supination decreased and pronation increased stability such that established treatment guidelines could be incorrectly applied. During evaluation in supination and 0° flexion, 9/12 -pUCL had greater than 35° laxity and, similarly, the mean laxity of -pUCL was similar to the UCL group in neutral rotation and 0° flexion, incorrectly suggesting a complete ligament tear. In comparison, mean laxity of the *UCL in pronation and 0° flexion was not different than -pUCL in neutral rotation and 0° flexion, emphasizing the stabilizing effect of pronation. CONCLUSIONS: Thumb MCP joint pronosupination significantly influenced the evaluation of joint stability, where pronation improved valgus stability in contrast to supination that tended to increase joint instability, In pronation and 0° flexion, a complete UCL injury could be misdiagnosed as a partial injury. In supination and 30° flexion, an intact UCL could be misdiagnosed as a partial UCL injury. In supination and 0°, a partial UCL injury could be misdiagnosed as a complete UCL injury. CLINICAL RELEVANCE: Accurate evaluation of thumb UCL stability is critical for guiding treatment. Variations in thumb MCP joint rotation during stress testing may influence clinical interpretation and, therefore, we recommend standardization of testing with the thumb MCP joint in neutral rotation.