A Cam Morphology Develops in the Early Phase of the Final Growth Spurt in Adolescent Ice Hockey Players: Results of a Prospective MRI-based Study.

BACKGROUND: Cam morphologies seem to develop with an increased prevalence in adolescent boys performing high-impact sports. The crucial question is at what age the cam morphology actually develops and whether there is an association with an aberration of the shape of the growth plate at the cam morphology site. QUESTIONS/PURPOSES: (1) What is the frequency of cam morphologies in adolescent ice hockey players, and when do they appear? (2) Is there an association between an extension of the physeal growth plate and the development of a cam morphology? (3) How often do these players demonstrate clinical findings like pain and lack of internal rotation? METHODS: A prospective, longitudinal MRI study was done to monitor the proximal femoral development and to define the appearance of cam morphologies in adolescent ice hockey players during the final growth spurt. Young ice hockey players from the local boys' league up to the age of 13 years (mean age 12 ± 0.5 years) were invited to participate. From 35 players performing on the highest national level, 25 boys and their parents consented to participate. None of these 25 players had to be excluded for known disease or previous surgery or hip trauma. At baseline examination as well as 1.5 and 3 years later, we performed a prospective noncontrast MRI scan and a clinical examination. The three-dimensional morphology of the proximal femur was assessed by one of the authors using radial images of the hip in a clockwise manner. The two validated parameters were: (1) the alpha angle for head asphericity (abnormal > 60°) and (2) the epiphyseal extension for detecting an abnormality in the shape of the capital physis and a potential correlation at the site of the cam morphology. The clinical examination was performed by one of the authors evaluating (1) internal rotation in 90° of hip and knee flexion and (2) hip pain during the anterior impingement test. RESULTS: Cam morphologies were most apparent at the 1.5-year follow-up interval (10 of 25; baseline versus 1.5-year follow-up: p = 0.007) and a few more occurred between 1.5 and 3 years (12 of 23; 1.5-year versus 3-year follow-up: p = 0.14). At 3-year follow-up, there was a positive correlation between increased epiphyseal extension and a high alpha angle at the anterosuperior quadrant (1 o'clock to 3 o'clock) (Spearman correlation coefficient = 0.341; p < 0.003). The prevalence of pain on the impingement test and/or restricted internal rotation less than 20° increased most between 1.5-year (1 of 25) and the 3-year follow-up (6 of 22; 1.5-year versus 3-year follow-up: p = 0.02). CONCLUSION: Our data suggest that a cam morphology develops early during the final growth spurt of the femoral head in adolescent ice hockey players predominantly between 13 to 16 years of age. A correlation between an increased extension of the growth plate and an increased alpha angle at the site of the cam morphology suggests a potential underlying growth disturbance. This should be further followed by high-resolution or biochemical MRI methods. Considering the high number of cam morphologies that correlated with abnormal clinical findings, we propose that adolescents performing high-impact sports should be screened for signs of cam impingement, such as by asking about hip pain and/or examining the patient for limited internal hip rotation. LEVEL OF EVIDENCE: Level I, prognostic study.

Performance and Return to Sport After Hip Arthroscopy in the National Basketball Association.

PURPOSE: To determine: (1) return to sport (RTS) rate in National Basketball Association (NBA) players following hip arthroscopy, (2) postoperative career length and games per season, (3) pre- and postoperative performance, and (4) postoperative performance compared with control players. METHODS: NBA athletes who underwent hip arthroscopy and matched controls were identified. RTS was defined as playing in at least 1 game after surgery. Player efficiency ratings were used for performance evaluation. Continuous variables of each group were compared using a 2-tailed paired samples Student t test for normally distributed data. χ2 was used to analyze categorical data. RTS was used as the primary outcome with statistical significance defined by a P value < .05. A Bonferroni correction was used to control for the remaining multiple comparisons with statistical significance defined by a P value ≤.008. RESULTS: Twenty-three players (24 hips) were analyzed (mean age 27.5 ± 3.1 years; mean experience in the NBA 5.8 ± 2.8 years at time of surgery). Small forwards (n = 8, 33.3%) represented the largest proportion of players that underwent hip arthroscopy. Twenty players (21 surgeries, 87.5%) were able to RTS in NBA at an average of 5.7 ± 2.6 months. The overall 1-year NBA career survival rate of players undergoing hip arthroscopy was 79.2%. Players in the control group (5.2 ± 3.5 years) had a similar career length as (P = .068) players who underwent surgery (4.4 ± 3.0 years). There was no significant (P = .045) decrease in games per season following surgery. There was no significant difference in performance postoperatively compared with preoperatively (P = .017) and compared with matched controls following surgery (P = .570). CONCLUSIONS: The RTS rate for NBA athletes after hip arthroscopy is high. There was no decrease in games played, career lengths, or performance following hip arthroscopy in NBA players versus preoperatively and matched controls. LEVEL OF EVIDENCE: Level III case-control study.

Changes in Knee and Trunk Alignment in People With Hip Pain and Healthy Controls When Using a Decline Board During Single-Leg Squat.

CONTEXT: Hip pain is associated with reduced hip muscle strength, range of movement (ROM), and decreased postural stability. Single-leg squat is a reliable and valid method to measure dynamic balance. OBJECTIVE: To evaluate the influence of physical characteristics and use of a decline board on squat performance in a hip pain population. DESIGN: Cross-sectional study setting. Clinical Patients: In total, 33 individuals scheduled for arthroscopic hip surgery were matched with 33 healthy controls. INTERVENTIONS: Hip and ankle ROM, hip strength, and trunk endurance were assessed, along with knee and trunk kinematics during squat on flat and 25° decline surfaces. MAIN OUTCOME MEASURES: Between-group and surface differences in alignment, between-group strength and ROM, and associations between alignment and physical characteristics were assessed and determined using mixed model analysis of variance and Pearson R. RESULTS: The hip pain group had significantly less strength and ROM for all directions except abduction strength and ankle dorsiflexion (P > .02). No differences existed between the 2 groups for trunk (P < .70) or knee displacement (P < .46) during squat on either surface. When the 2 groups were combined (n = 66), decline squat significantly reduced knee medial displacement in both limbs by approximately 1 cm (P < .01). Decline squat reduced trunk lateral movement on 1 side only (P = .03). Reduced knee displacement during decline squat showed fair association with less hip-extension strength (r = -.29), hip-flexion strength (r = -.25), and less dorsiflexion (r = -.24). Strength and range were not associated with trunk displacement. CONCLUSIONS: Decline squat reduced medial knee and lateral trunk displacement regardless of hip pain. Reductions may be greater in those with lesser hip muscle strength and dorsiflexion. Use of a decline board during squat for improving knee and trunk alignment should be considered as a goal of exercise intervention.

Japanese version of the international PROMs "Vail Hip Score": Reliability, validity, and responsiveness according to the COSMIN checklist.

BACKGROUND: This study aimed to develop a Japanese version of the international PROMs "Vail Hip Score (Vail10)" and to establish its reliability, validity, and responsiveness with COSMIN check-list. METHODS: The study was conducted from March 2016 to October 2017 and included 46 patients totaling 47 joints. Disorders included 30 cases of FAI (55%), 13 cases of DDH (28%), and 4 others (8%). We administered an identical set of PROMs (5 measures: Japanese-version iHOT12 (pilot draft), Japanese-version Vail10, Japanese-version Oxford Hip Score, JHEQ, and SF36) twice in these subjects. We determined interclass correlation coefficients for the first and second round [ICC(1,2)], as well as the Cronbach α coefficient for patient responses to each of the 10 items in Vail10. In addition, we determined Spearman rank correlation coefficients of Vail10, OHS, JHEQ, satisfaction VAS, the 8 subscales of SF36, and the 3 QOL summary scores. RESULTS: ICC for the total score of all 10 items in Vail10 was 0.96. Cronbach α coefficient was 0.96. Bland-Altman plot analysis showed a solid agreement. Regarding the validity, Spearman rank correlation coefficients, only satisfaction VAS, and SF36 subscales of PF and BP had r > 0.45 (p < 0.01 in both administration rounds). The SDC (1.32) was smaller than the MIC (8.14). CONCLUSIONS: After developing the Japanese version of Vail10, we examined its Reliability, validity, and responsiveness by administering the measure to patients with acetabular labral tear. Correlations were strong and demonstrated the efficacy of the Japanese version of Vail10.

Posterior Bony Impingement-Potential Mechanism of Ligamentum Teres Tears.

PURPOSE: To describe a potential causal mechanism of ligamentum teres (LT) tears, a specific treatment for posterior impingement of the LT, and to report the minimum 2-year outcome of this treatment. METHODS: We retrospectively reviewed data collected from 1,251 hip arthroscopies performed by the senior surgeon over a 26-month period. During this time, 424 LT tears were identified including 9 patients with isolated partial LT tears caused by impingement of the LT against a prominent acetabular fossa posterior wall and no other intra-articular pathology. All 9 patients were treated with LT tear debridement and excision of the impinging bony prominence using an arthroscopic burr. Patients were followed with a modified Harris hip score and nonarthritic hip score for a minimum of 24 months (mean, 29 months; range, 24-38 months). RESULTS: After surgery, all patients returned to their preinjury level of activity. The modified Harris hip score increased from a mean of 58.9 preoperatively (range, 41.8-84.7) to 89.2 (range, 70.3.5-96.7) (P = .02) at a minimum of 2-year follow-up. Similarly, the nonarthritic hip score increased from a mean of 56.2 (range, 35-90) to 91.9 (range, 81.5-98.5) (P = .01) at a minimum of 2 years after surgery. There were no complications associated with the procedure and no revision surgeries performed over the 2-year follow-up. CONCLUSIONS: LT tears may, very uncommonly, be caused by impingement of the mid-part of the ligament against a prominent posterior acetabular fossa edge. In this group of 9 cases, debridement of the torn ligament segment, in combination with resection of the impinging bone, was associated with marked symptomatic improvement and full return to activities for a minimum of 2 years. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Recognizing and Managing Snapping Hip Syndrome in Dancers.

BACKGROUND: Snapping hip syndrome (SHS) is a common hip pathology in dancers. SHS can be either internal or external, resulting from muscle tendon tightness from repetitive hip flexion and extension, accompanied with hip abduction and/or external rotation. Muscular tightness may cause the tendon to become taut and snap over a bony prominence during hip movement, leading to muscular weakness and reduced range of motion from pain. Because SHS is poorly identified and can present similarly to other hip pathologies, many SHS incidences are underreported or misdiagnosed. Though SHS can begin as a harmless popping sensation, pain can become severe enough to limit dancers' activities and potentially result in the development of concomitant issues. EVALUATION: Physical examination for snapping hip includes moving the hip from flexion, abduction, and external rotation (FABER) into extension, adduction, and rotated to a neutral position. Dynamic ultrasound can also be used to study SHS, as using this method allows clinicians to observe the snapping tendon in real-time. Radiographs and magnetic resonance imaging may serve to rule out other differential diagnoses. MANAGEMENT: Conservative management through rehabilitative therapy is the standard for initial management. In severe cases, arthroscopic intervention may be useful in releasing tension in the pathological tendon. Active rest with training modifications should be attempted to mitigate further injury. CONCLUSION: Early and comprehensive examination and management can help to reduce SHS risk and potentially decrease the ability of this debilitating condition to derail a dancer's career.

Prevalence and severity of hip and groin pain in sub-elite male football: a cross-sectional cohort study of 695 players.

The purpose of this study was twofold: (a) to investigate the prevalence of hip and groin pain in sub-elite male adult football in Denmark and (b) to explore the association between prevalence and duration of hip and groin pain in the previous season with the Copenhagen Hip and Groin Outcome Score (HAGOS) in the beginning of the new season. In total 695 respondents from 40 teams (Division 1-4) were included. Players completed in the beginning of the new season (July-Sept 2011) a self-reported paper questionnaire on hip and/or groin pain during the previous season and HAGOS. In total 49% (95% CI: 45-52%) reported hip and/or groin pain during the previous season. Of these, 31% (95% CI: 26-36%) reported pain for >6 weeks. Players with the longest duration of pain during the previous season had the lowest HAGOS scores, when assessed at the beginning of the new season, P < 0.001. This study documents that half of sub-elite male adult football players report pain in the hip and/or groin during a football season. The football players with the longest duration of pain in previous season displayed the lowest HAGOS scores in the beginning of the new season.

Do Neuromuscular Alterations Exist for Patients With Acetabular Labral Tears During Function?

PURPOSE: To determine if contact forces and electromyography (EMG) muscle amplitudes were altered during the lunge for patients with symptomatic labral tears compared with asymptomatic control subjects. METHODS: Surface electromyography electrodes were placed over the gluteus medius, gluteus maximus, adductor longus, and rectus femoris muscles of the patients' involved limb and matched limb of asymptomatic controls. Subjects performed 3 trials of the lunge on a clinical force platform. An electrogoniometer tracked knee flexion motion during testing. Average root mean squared EMG muscle amplitudes for each muscle were calculated for the descent and ascent phases of the lunge, represented as a percentage of maximum activity (%MVIC). Peak knee flexion was calculated from the goniometer (°). The dependent variables from the force platform were lunge distance (%height), contact time (seconds), vertical impact force (%BW), and force impulse (%BW*s). Dependent variables were compared between groups using either independent samples t tests or Mann-Whitney U tests. Relations between dependent variables were assessed with Spearman Rho correlation coefficients. The level of significance was set at P ≤ .05. RESULTS: Twenty-one patients with symptomatic unilateral labral tears (14 females, 7 males) and 17 asymptomatic control subjects (11 females, 6 males) participated in this study. Average gluteus maximus EMG muscle amplitudes were reduced for symptomatic labral patients compared with asymptomatic controls during lunge ascent (51.6 ± 31.1 v 71.7 ± 36.3 [mean difference (MD): 20.1% (-2.4%, 42.6%)], P = .042). Average vertical impact force was reduced (21.8 ± 5.5 v 26.8 ± 7.3 [MD: 5.1%BW (0.84%BW, 9.3%BW)], P = .02) and average contact time (1.8 ± 0.4 v 1.5 ± 0.4 [MD: 0.27 seconds (0.006 seconds, 0.54 seconds)], P = .045) and force impulse (188.4 ± 42.4 v 162.6 ± 33.3 [MD: 25.8%BW*s (0.3%BW*s, 51.4%BW*s)], P = .042) were increased for symptomatic labral patients compared with asymptomatic controls. Vertical impact force was inversely correlated with gluteus medius muscle amplitudes during lunge descent for symptomatic labral patients (r = -0.452, P = .045). CONCLUSIONS: Our study shows that contact forces and EMG muscle amplitudes are altered during the lunge for patients with symptomatic labral tears. The presence of a relation between muscle amplitudes and contact forces suggests that targeting muscle impairments may restore function in these patients. LEVEL OF EVIDENCE: Level III, case-control study.

The Hip in Ice Hockey: A Current Concepts Review.

Ice hockey is a fast, physical sport with unique associated biomechanical demands often placing the hip in forced and repetitive supraphysiological ranges of motion. Ice hockey players commonly endure and are sidelined by nebulous groin injury or hip pain. Underlying causes can be chronic or acute and extra-articular, intra-articular, or "hip-mimicking." This article serves to review common hip-related injuries in ice hockey. For each, we define the particular condition; comment on risk factors and preventive strategies; discuss key historical, physical examination, and imaging findings; and finally, suggest nonoperative and/or operative treatment plans.

[Gait Analysis in Patients with Hip Disorders]. / Pohybová analýza u chorob kycelního kloubu.

Recent studies have shown that the evaluation of both conservative and surgical therapy cannot do without gait analysis. Orthopaedic textbooks, with some exceptions, deal in great detail with a thorough clinical examination of the patient but gait assessment is mentioned only marginally. More attention is paid to gait analysis in rehabilitation medicine. Motion and gait analysis laboratories equipped with optoelectronic cameras and force platforms were first developed for cerebral palsy children. Recently, several studies have been published on the use of these methods in disorders of hip and knee joints or spine diseases. Key words: gait analysis, hip joint.

Long-Term Function following Periprosthetic Fractures.

PURPOSE OF THE STUDY Clinical results of long-term follow-up after traumatic periprosthetic femur fractures and different therapies (ORIF vs. revision arthroplasty) MATERIAL AND METHODS The Visual Analog Scale (VAS), Harris-Hip-Score (HHS), Oxford-Hip-Score (OHS), Oxford-Knee-Score (OKS), Knee-Society-Score (KSS), SF-36 Questionnaire and Funktionsfragebogen Hannover (FFH) were used to evaluate outcome and functionality. Radiological examinations were performed and the Vancouver (THA) and Lewis and Rorabeck (TKA) classifications used. RESULTS 70 patients suffered a periprosthetic hip fracture (29× revision prosthesis, 41x ORIF), 23 patients underwent an ORIF due to periprosthetic fracture of a TKA (total mean age 75.2 years). 47 patients (follow-up rate 51%) were examined 40 months after surgery (mean age 72 years) (THA: 16× revision, 23× ORIF, TKA: 8× ORIF). The VAS revealed significant less pain in the group that had undergone revision hip arthroplasty than in the ORIF group: 3.9±1 vs. 5.1±1.7 (p<0.05), respectively. 5/16 patients with revision arthroplasty had excellent or good results in the HSS compared to 3/23 patients after ORIF. The OHS yielded excellent or good results in 12/16 patients after revision arthroplasty vs. 10/23 after ORIF. The VAS after ORIF in patients who suffered periprosthetic knee fractures was 4.9±2.1. 3/8 patients achieved excellent or good results according to the OKS. CONCLUSION Every functional score (HSS, OHS, FFH, SF-36) of those patients who had undergone revision arthroplasty was slightly higher and their VAS significantly lower than the scores of the patients after ORIF. Key words: periprosthetic fractures, trauma, open reduction and internal fixation, revision arthroplasty.

Clinician-friendly lower extremity physical performance tests in athletes: a systematic review of measurement properties and correlation with injury. Part 2--the tests for the hip, thigh, foot and ankle including the star excursion balance test.

OBJECTIVE: To review the quality of literature and measurement properties of physical performance tests (PPTs) of the lower extremity in athletes. METHODS: Using the PICOS method we established our research question as to whether individual PPTs of the lower extremity have any relationship to injury in competitive athletes ages 12 years to adult (no limit). A search strategy was constructed by combining the terms 'lower extremity' and synonyms for 'performance test' and names of performance tests with variants of the term 'athlete'. After examining the knee in part 1 of this 2 part series, the current report focuses on findings in the rest of the lower extremity. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed and the Consensus-based Standards for the selection of health Measurement Instruments (COSMIN) checklist was used to critique the methodological quality of each paper. A second measure was used to analyse the quality of the measurement properties of each test. RESULTS: Thirty-one articles examined the measurement properties of 14 PPTs pertaining to the lower extremity. The terminology used to name and describe the tests and methodology by which the tests were conducted was inconsistent. The star excursion balance test performed in three directions (anterior, posteromedial, and posterolateral) appears to be the only test to be associated with increased injury risk. There is moderate evidence that the one leg hop for distance and the hexagon hop can distinguish between normal and unstable ankles. There is also moderate evidence that the medial hop can distinguish between painful and normal hips in dancers. CONCLUSIONS: Currently, there is relatively limited research-backed information on PPTs of the lower extremity in athletes. We would suggest convening an international consortium comprised of experts in sports to standardise the descriptions and methodologies, and to set forth a research agenda to establish definitively the measurement properties of the most common PPTs.

Hip Arthroscopy in High-Level Baseball Players.

PURPOSE: To report the results of hip arthroscopy among high-level baseball players as recorded by outcome scores and return to baseball. METHODS: All patients undergoing hip arthroscopy were prospectively assessed with the modified Harris Hip Score. On review of all procedures performed over a 12-year period, 44 hips were identified among 41 intercollegiate or professional baseball players who had achieved 2-year follow-up. RESULTS: Among the 41 players, follow-up averaged 45 months (range, 24 to 120 months), with a mean age of 23 years (range, 18 to 34 years). There were 23 collegiate (1 bilateral) and 18 professional (2 bilateral) baseball players, including 10 Major League Baseball players. Of the 8 Major League Baseball pitchers, 6 (75%) also underwent ulnar collateral ligament elbow surgery. Improvement in the modified Harris Hip Score averaged 13 points (from 81 points preoperatively to 94 points postoperatively); a paired-samples t test determined that this mean improvement of 13 points was statistically significant (P < .001). Players returned to baseball after 42 of 44 procedures (95%) at a mean of 4.3 months (range, 3 to 8 months), with 90% regaining the ability to participate at their previous level of competition. There were no complications. Three players (1 bilateral) underwent repeat arthroscopy. CONCLUSIONS: This study supports the idea that arthroscopic treatment for a variety of hip pathologies in high-level baseball players provides a successful return to sport and improvement in functional outcome scores. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Investigating Strength and Range of Motion of the Hip Complex in Ice Hockey Athletes.

CONTEXT: Ice hockey athletes frequently injure the hip complex via a noncontact mechanism. The authors investigated patterns of strength and range of motion (ROM) to establish major differences compared with soccer athletes. Soccer athletes were compared with ice hockey athletes due to similarities between the 2 sports with regard to the intermittent nature and high number of lower-limb injuries. OBJECTIVE: To compare the differences in ROM and strength of the hip for both the dominant (Dom) and nondominant (Ndom) limbs in ice hockey and soccer athletes. DESIGN: Case-control study. SETTING: Bilateral ROM in hip flexion in sitting (FS) and lying (FL), extension, abduction, adduction, and internal rotation (IR) and external rotation (ER) were measured using a goniometer and assessed for strength using a handheld dynamometer on both the Dom and Ndom limbs. PARTICIPANTS: 24 male, active, uninjured NCAA Division III ice hockey (16) and soccer (8) athletes. MAIN OUTCOME MEASURES: ROM and strength for hip FS, FL, extension, abduction, adduction, IR, and ER. A mixed-model ANOVA was used to investigate interactions and main effects. RESULTS: Ice hockey athletes exhibited greater hip-adduction ROM than soccer athletes in the Dom leg (both P = .002) and when both limbs were combined (P = .010). Ice hockey athletes had less ROM in ER (P = .042) than soccer athletes. Ice hockey athletes displayed less strength in adduction in their Ndom leg than in their Dom leg (P = .02), along with less adduction than soccer players in their Ndom leg (P = .40). Ice hockey athletes displayed less strength in hip adduction (P = .030), FS (P = .023) and FL (P = .030) than soccer athletes. CONCLUSIONS: The findings suggest that ice hockey athletes may present an at-risk profile for noncontact hip injuries in comparison with soccer athletes with regard to strength and ROM of the hip.

The hip fluid seal--Part I: the effect of an acetabular labral tear, repair, resection, and reconstruction on hip fluid pressurization.

PURPOSE: The acetabular labrum is theorized to be important to normal hip function by creating intra-articular fluid pressurization through the hip fluid seal. However, the effect of a labral tear or partial labral resection, and interventions including labral repair and labral reconstruction, on the hip fluid seal remains to be defined. The purpose of this study was to characterize intra-articular fluid pressurization in six labral conditions: intact, tear, repair (looped vs. through sutures), partial resection, reconstruction with iliotibial band, and complete resection. METHODS: Eight cadaveric hips with a mean age of 47.8 years (SD 4.3, range 41-51) were included in the study. For each labral condition, the hip was compressed with a force of 2.7 times body weight (2,118 N) while intra-articular pressure was continuously measured with 1.0 × 0.3 mm pressure transducers. Peak intra-articular pressure measurements for each condition were normalized relative to the intact state. Statistical analyses were performed utilizing linear mixed-effects models with repeated measures analysis. RESULTS: Intra-articular fluid pressurization of the intact state varied from 78 to 422 kPa (mean 188 kPa ± SD 120). Labral tear, partial resection, and complete resection resulted in average pressurization of 75 ± 33, 53 ± 37, and 24 ± 18 %, respectively compared with the intact state. Through type labral repair resulted in significantly greater increases in pressurization from the labral tear state, compared with the looped type repair (median increase; +46 vs. -12 %, p = 0.029). Labral reconstruction resulted in a mean pressurization of 110 ± 38 % relative to intact state, with a significant 56 ± 47 % improvement in pressurization compared with partial labral resection (p = 0.009). CONCLUSIONS: Partial labral resection caused significant decreases in intra-articular fluid pressurization. Through type labral suture repair restored the fluid pressurization better than looped type repairs. Labral reconstruction significantly improved pressurization to levels similar to the intact state. This study demonstrated the effect of labral tears and partial resections on intra-articular fluid pressurization via the hip fluid seal, and it also demonstrated improvements in pressurization seen with through type labral repairs and labral reconstructions.

The hip fluid seal--Part II: The effect of an acetabular labral tear, repair, resection, and reconstruction on hip stability to distraction.

PURPOSE: The acetabular labrum is theorized to be important to normal hip function by providing stability to distraction forces through the suction effect of the hip fluid seal. The purpose of this study was to determine the relative contributions of the hip capsule and labrum to the distractive stability of the hip, and to characterize hip stability to distraction forces in six labral conditions: intact labrum, labral tear, labral repair (looped vs. through sutures), partial resection, labral reconstruction with iliotibial band, and complete resection. METHODS: Eight cadaveric hips with a mean age of 47.8 years (SD 4.3, range 41-51 years) were included. For each condition, the hip seal was broken by distracting the hip at a rate of 0.33 mm/s while the required force, energy, and negative intra-articular pressure were measured. For comparisons between labral conditions, measurements were normalized to the intact labral state (percent of intact). RESULTS: The relative contribution of the labrum to distractive stability was greatest at 1 and 2 mm of displacement, where it was significantly greater than the role of the capsule and accounted for 77 % (SD 27 %, p = 0.006) and 70 % (SD 7 %, p = 0.009) of total distractive stability, respectively. The relative contribution of the capsule to distractive stability increased with progressive displacement, providing 41 % (SD 49 %) and 52 % (SD 53 %) of distractive stability at 3 and 5 mm of distraction, respectively. The maximal distraction force required to break the hip seal in the intact labral state (capsule removed) varied from 124 to 150 N. Labral tear, partial resection, and complete resection resulted in average maximal distraction forces of 76 % (SD 34 %), 29 % (SD 26 %), and 27 % (SD 22 %), respectively, compared to the intact state. Through type labral repairs resulted in significantly greater improvements (from the labral tear state) in maximal negative pressure generated, compared to looped type repairs (median increase; +32 vs. -9 %, p = 0.029). Labral reconstruction resulted in a mean maximal distraction force of 66 % (SD 35 %), with a significant improvement of 37 % compared to partial labral resection (p < 0.001). CONCLUSION: The acetabular labrum was the primary hip stabilizer to distraction forces at small displacements (1-2 mm). Partial labral resection significantly decreased the distractive strength of the hip fluid seal. Labral reconstruction significantly improved distractive stability, compared to partial labral resection. The results of this study may provide insight into the relative importance of the capsule and labrum to distractive stability of the hip and may help to explain hip microinstability in the setting of labral disease.

Growth plate alteration precedes cam-type deformity in elite basketball players.

BACKGROUND: Vigorous sporting activity during the growth years is associated with an increased risk of having a cam-type deformity develop. The underlying cause of this osseous deformity is unclear. One may speculate whether this is caused by reactive bone apposition in the region of the anterosuperior head-neck junction or whether sports activity alters the shape of and growth in the growth plate. If the latter is true, then one would expect athletes to show an abnormal shape of the capital growth plate (specifically, the epiphyseal extension) before and/or after physeal closure. QUESTIONS/PURPOSES: We therefore raised three questions: (1) Do adolescent basketball players show abnormal epiphyseal extension? (2) Does the epiphyseal extension differ before and after physeal closure? (3) Is abnormal epiphyseal extension associated with high alpha angles? METHODS: We performed a case-control comparative analysis of young (age range, 9-22 years) male elite basketball athletes with age-matched nonathletes, substratified by whether they had open or closed physes. We measured epiphyseal extension on radial-sequence MRI cuts throughout the cranial hemisphere from 9 o'clock (posterior) to 3 o'clock (anterior). Epiphyseal extension was correlated to alpha angle measurements at the same points. RESULTS: Epiphyseal extension was increased in all positions in the athletes compared with the control group. On average, athletes showed epiphyseal extension of 0.67 to 0.83 versus 0.53 to 0.71 in control subjects. In the control group epiphyseal extension was increased at all measurement points in hips after physeal closure compared with before physeal closure. In contrast, the subgroup of athletes with a closed growth plate only had increased epiphyseal extension at the 3 o'clock position compared with the athletes with an open [corrected] growth plate (0.64-0.70). We observed a correlation between an alpha angle greater than 55° and greater epiphyseal extension in the anterosuperior femoral head quadrant: the corresponding Spearman r values were 0.387 (all hips) and 0.285 (alpha angle>55°) for the aggregate anterosuperior quadrant. CONCLUSIONS: These findings suggest that a cam-type abnormality in athletes is a consequence of an alteration of the growth plate rather than reactive bone formation. High-level sports activity during growth may be a new and distinct risk factor for a cam-type deformity.

Labral injuries of the hip in rowers.

BACKGROUND: Injuries of the hip in the adolescent and young adult athlete are receiving more attention with advances in the understanding of femoroacetabular impingement (FAI), labral pathology, and hip arthroscopy. Labral tears have not been well characterized in rowers. QUESTIONS/PURPOSES: The purposes of this study were (1) to describe the clinical presentation of labral pathology in rowers; (2) to describe the MRI and radiographic findings of labral pathology in rowers; and (3) to determine the likelihood that a rower with labral injury, treated arthroscopically, will return to sport. METHODS: We conducted a review from August 2003 to August 2010 to identify all rowers with MRI-confirmed intraarticular pathology of the hip presenting to our institution. Baseline demographics, symptoms and physical findings, and location of the labral tear with associated pathology, management, and early followup were recorded. The review yielded a total of 21 hips (18 rowers, three with bilateral labral pathology) with a mean patient age of 18.5 years (range, 14-23 years). Most of the rowers (85%) were female and the series included prep school (44%) and collegiate rowers (56%). Eighteen of the 21 hips (85%) eventually underwent arthroscopic surgery at our institution. RESULTS: A large majority of patients had isolated groin pain (71%) and physical findings consistent with impingement (81%). There was no single, dominant location for the labral tears on MRI. Among the 18 patients who had surgery, 10 (56%) returned to rowing, six (33%) never returned, and return data were not available for two (11%) at a mean of 8 months (range, 3-25 months) after surgery. CONCLUSIONS: The repetitive motions of the hip required for rowing may be a factor leading to intraarticular labral injuries in the athletes. Underlying anatomic abnormalities of the hip such as FAI may predispose certain patients to these injuries. However, many patients treated arthroscopically did not return to sport at a mean of 8 months after surgery.

Sports hip injuries: assessment and management.

Over the past 10 years, the understanding, assessment, and management of hip pain and injuries in the athlete have improved. Traditionally, the evaluation of hip pain and injuries was limited to obvious disorders, such as hip arthritis and fractures, or disorders that were previously considered to be simply soft-tissue strains and contusions, such as groin pulls, hip pointers, and bursitis. Two parallel tracks of progress have improved understanding of the complexities of hip joint athletic injuries and the biomechanical basis of early hip disease. In the field of sports medicine, improved diagnostic skills now allow better interpretation of debilitating intra-articular hip disorders and their effects on core performance. In the field of hip preservation, there has been an evolution in understanding the effects of biomechanical mismatches between the femoral head and the acetabulum on the development of early hip damage, injury, and arthritis. The integration of these two parallel fields has accelerated the understanding of the importance of hip biomechanics and early hip injury in human performance and function.

Treatment of a hip capsular injury in a professional soccer player with platelet-rich plasma and bone marrow aspirate concentrate therapy.

This report presents a 27-year-old male professional soccer player who developed heterotopic ossification of his hip capsule and gluteus minimus tendon after an arthroscopic hip procedure. After removal of the heterotopic bone, the patient had a symptomatic deficiency of his hip capsule and gluteus minimus tendon. A series of orthobiologic treatments with platelet-rich plasma and bone marrow aspirate concentrate improved the patient's pain and strength as well as the morphologic appearance of the hip capsule and gluteus minimus tendon on magnetic resonance imaging. A series of motion analyses demonstrated significant improvement in his stance-leg ground reaction force and hip abduction, as well as linear foot velocity at ball strike and maximum hip flexion following ball strike in his kicking leg. Level of evidence IV.