Simultaneous Le Fort III and Le Fort I Osteotomy: Surgical Outcomes and Clinical Parameters.

INTRODUCTION: Simultaneous Le Fort III/I (LF III/I) osteotomies are often performed when a differential advancement of the upper and lower midface is needed. This study aims to evaluate midface position preoperative and 1 week postoperative in patients with severe midface hypoplasia. In addition, this study aims to compare the planned surgical movements to the actual postoperative movements. MATERIALS AND METHODS: A retrospective review was conducted using cephalometry for patients treated with a simultaneous LF III/I osteotomy at a single institution. Osteotomies were performed during 1980-2018 on skeletally mature patients with a craniofacial syndrome, with clinical and radiographic follow-up available. RESULTS: Twelve patients met the inclusion criteria with a mean age of 20.2±6.4 years. Treatment resulted in statistically significant anterior movements related to Orbitale, anterior nasal spine, A Point, and the upper incisor tip, and inferior movements related to anterior nasal spine, A Point, upper and lower incisor tips, B point, and pogonion. Stability after 1 year showed only statistically significant changes at ANB. The predictable error for planned movements versus actual movements was greater in the vertical plane than the horizontal plane. CONCLUSIONS: A simultaneous LF III/I osteotomy significantly improved the midface position and occlusal relationship in syndromic patients with midface hypoplasia in a predictable manner. Further multicenter studies with larger sample sizes are needed to validate the conclusions.

Longitudinal Skeletal Growth Analysis of Mandibular Asymmetry in Unoperated Patients With Unilateral Craniofacial Microsomia (UCFM).

PURPOSE: To examine the growth rate discrepancy of the affected and unaffected ramus heights in Pruzansky Type I and Type II mandibles. METHODS: This is a serial retrospective longitudinal growth study of 30 untreated patients (21 males and 9 females) with UCMF (age range from 5 years to 14 years). The mean age of patients was 8.5 years, and the mean follow-up records were 3.7 years. There were 13 patients in group I with a Pruzansky Type I mandible and 17 patients in group II with a Pruzansky Type II. The unaffected side of the mandible served as a control. Eighteen cephalometric parameters were examined at each of the two-time intervals. RESULTS: In patients with Pruzansky Type I mandible, the affected ramus grew on average 1.41 mm per year; the unaffected ramus grew 1.66 mm per year during the same period. In patients with Pruzansky Type II mandible, the affected ramus grew on average 0.84 mm per year; during the same period, unaffected ramus grew 1.79 per year. When the growth rate of the ramus height on the affected side was compared to the unaffected side, there was no statistically significant difference in Pruzansky Type I mandibles (p > .05); however, there was a statistically significant difference in the Pruzansky Type II mandibles (p < .05). CONCLUSION: The growth rate discrepancy of the affected and unaffected ramus heights was more severe in Pruzansky Type II mandibles than Pruzansky Type I mandibles explaining the progressive nature of facial asymmetry in Pruzansky II mandibles.

Correction of Severe Facial Asymmetry in Patients With Unilateral Craniofacial Microsomia Using Computer-Aided Design/Computer-Aided Manufacturing Technology: An Evaluation of Postsurgical Results.

ABSTRACT: This is a retrospective study to evaluate the postsurgical position of the maxilla and mandible in 5 matured craniofacial patients with unilateral craniofacial microsomia who underwent 2 jaw surgical procedures using computerized surgical planning. The craniofacial surgeon and orthodontist completed the virtual surgical treatment plan with a biomedical engineer's assistance via a web meeting. The treatment plan of each patient included 2 jaw surgery with genioplasty. At the maxillary dental midline, the planned mean advancement was 4 mm; yaw, a rotational correction towards the unaffected side was 4.96 mm; and impaction was 2.74 mm. The mean advancement measured at point B was 10.5 mm, and the rotational correction towards the unaffected side was 6.58 mm. The mean advancement following genioplasty was 8.43 mm, and the mean transverse correction was 6.33 mm towards the midsagittal plane. The intermediate surgical splint, final surgical splint, bone graft templates, and cutting guides were constructed utilizing computer-aided design/computer-aided manufacturing technology. The surgeon executed the treatment plan in the operating room using appropriate computer-generated guides and splints. A postsurgical cone-beam computed tomography scan was obtained and superimposed on the surgical treatment plan using Simplant OMS 10.1 software. The cranial base was used as a reference for superimposition. Three-dimensional color-coded displacement maps were generated to visually and quantitatively assess the surgical outcome. There was a mean error of 0.88 mm (+0.30) for the position of the maxillary anatomical structures from the planned position, and the anterior mandibular anatomical structures were on average 0.96 mm (+0.26) from the planned position.

What Is the Association Between Articular Cartilage Damage and Subsequent THA 20 Years After Hip Arthroscopy for Labral Tears?

BACKGROUND: Few studies have examined long-term outcomes for patients after arthroscopic treatment for intraarticular hip conditions, and none have done so beyond 10 years postarthroscopy. Examining outcomes beyond 10 years is necessary to determine factors that contribute to conversion to THA in patients undergoing hip arthroscopy for labrochondral damage. QUESTIONS/PURPOSES: (1) What is hip survivorship free from THA in patients who underwent arthroscopic labral débridement, with or without chondroplasty at least 15 years before? (2) What factors are associated with conversion to THA after arthroscopic labral débridement, with or without chondroplasty? (3) Can these data be used to estimate the risk of conversion to THA based on patient- and hip-related factors? METHODS: Between 1989 and 2000, one surgeon performed 552 arthroscopic hip procedures for symptomatic labral tears, with or without associated articular cartilage damage. Of these, the hip status was known in 404 hips (73%) at a minimum of 15 years after the index procedure, with 20 of those patients having died during the followup period. During the study period, patients were offered hip arthroscopy for labral tears with mechanical symptoms, with or without underlying articular cartilage damage. Patient age, sex, acetabular and femoral head Outerbridge grade at surgery, and presence of labral tear were recorded. We determined survivorship free from THA using a Kaplan-Meier survivorship estimator. A stepwise multivariable logistic regression analysis was conducted to determine factors associated with the eventual conversion to THA after hip arthroscopy for labrochondral injuries. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated for all significant independent factors. Odds ratios for combinations of significant factors were used to create a risk assessment. RESULTS: The survivorship free from conversion to THA at 20 years was 59% (95% CI, 53-64. Factors that affected survival included age ≥ 40 years and the presence of combined femoral head and acetabular chondral damage. After controlling for confounding factors, we found that age ≥ 40 years (OR, 2.0; 95% CI, 1.2-3.4; p = 0.011), the absence of all chondral damage (OR, 0.1; 95% CI, 0.03-0.32; p < 0.001), the presence of acetabular damage with severe femoral head damage (OR, 5.0; 95% CI, 2.4-10.3; p < 0.001), and the presence of severe acetabular damage with femoral head damage (OR, 3.7; 95% CI, 2.0-6.8; p < 0.001) were associated with conversion to THA at long-term followup. Based on the calculated ORs, the probability of conversion to THA by 20 years postarthroscopic treatment for labrochondral injuries ranged from 12% (95% CI, 8-17) for a patient younger than 40 years with a Grade 0-II femoral and acetabular Outerbridge grade to 92% (95% CI, 86-95) for a patient older than 40 years with a Grade III-IV femoral and acetabular Outerbridge grade. CONCLUSIONS: Our study revealed that survivorship free from THA at 20 years after arthroscopic labral débridement was associated with both patient age at time of index procedure and, more importantly, the presence of combined femoral head and acetabular chondral damage. Patients should be counseled as to the increased probability of conversion to THA, depending on the health of their articular cartilage after surgery. Future studies should examine survivorship free from THA or clinical symptoms in patients undergoing hip arthroscopy with bone reshaping procedures or with labral repair or reconstruction up to and exceeding 20 years. LEVEL OF EVIDENCE: Level III, therapeutic study.

Maxillomandibular and occlusal relationships in preadolescent patients with syndromic craniosynostosis treated by LeFort III distraction osteogenesis: 10-year surgical and phenotypic stability.

INTRODUCTION: LeFort III distraction osteogenesis may be indicated in the treatment of syndromic craniosynostosis with severe midface retrusion. This study investigates long-term changes in patients undergoing distraction as children, and compares outcomes to an unaffected, untreated control. METHODS: Fifteen patients (9 males, 6 females) with syndromic craniosynostosis treated by LeFort III distraction at an average age of 4.9 ± 1.5 years were identified. Lateral cephalograms at predistraction, immediate, 1-, 5-, and 10-year postdistraction were superimposed using the best-fit of cranial base details. An untreated, unaffected matched control was obtained from the American Association of Orthodontists Foundation Legacy Collection. Differences in landmark location and cephalometric relationships were assessed between time points and between treatment and control groups. RESULTS: LeFort III distraction produced an average advancement of 14.86 ± 5.14 mm at A-point and 10.54 ± 3.78 mm at orbitale. This advancement produced overcorrection of anteroposterior occlusal relationships and phenotypic correction of midface position. Surgical stability over a 10-year follow-up was excellent. Posttreatment growth was characterized by absent anteroposterior maxillary growth, preservation of dentoalveolar development and maxillary remodeling, and delayed mandibular growth. Subsequent growth resulted in a long-term phenotypic relapse of pretreatment Class III maxillomandibular relationship and negative overjet. CONCLUSIONS: LeFort III distraction osteogenesis produces stable advancement of the midface. Overcorrection is required for long-term phenotypic stability because of deficient postdistraction sagittal midface growth. Late mandibular growth contributes to underestimation of the amount of distraction required to produce long-term phenotypic correction.

Treacher Collins Syndrome and Tracheostomy: Decannulation Using Mandibular Distraction Osteogenesis.

INTRODUCTION: Treacher Collins syndrome (TC) and Pierre Robin sequence (RS) are associated with hypoplastic mandible, glossoptosis, and consequent airway obstruction. Although TC and RS are often grouped together, airway outcomes of bilateral mandibular distraction osteogenesis (MDO) have not been specifically studied in TC. The purpose of this study is to report on the clinical outcomes of MDO in the TC patient population. MATERIALS AND METHODS: A twenty-year single-institution retrospective review of all patients with TC who underwent bilateral MDO was performed. Twenty-four patients were identified after exclusion due to different diagnoses or insufficient medical records. Data on comorbidities, airway status, MDO operations, and complications were collected. Data were compared with published clinical outcomes in RS and data for 13 RS patients from our institution. RESULTS: Surgical success, defined as prevention of imminent tracheostomy or successful decannulation within 1 year after primary distraction, was observed in 21% of TC patients and 65% of RS patients (P = 0.01). Repeat distraction was necessary for 11 TC patients (46%) and 1 RS patient. Complications were divided into minor, moderate, and major based on need for invasive management. Overall, 67% of TC patients had complications, 20% of which were major. CONCLUSIONS: Clinical outcomes to airway function after MDO are significantly inferior in patients with TC compared with patients with RS. Repeat MDO and longer course to decannulation are more prevalent in patients affected by TC.

Incorporating Hip Arthroscopy Into A Practice.

Hip arthroscopy is one of the most rapidly growing areas in orthopaedic surgery because of increased awareness of nonarthritic hip pathologies, advanced imaging modalities, and advanced techniques to reproducibly manage nonarthritic hip pathologies within a deep soft-tissue envelope and a constrained joint. In addition, more academic medical centers are providing residents with education on hip arthroscopy, and many hip preservation fellowships and courses are helping increase awareness of nonarthritic hip pathologies. Nonarthritic hip pathologies currently managed via hip arthroscopy include nonrepairable labral lesions, femoroacetabular impingement, hip instability, and hip fractures. Periarticular hip pathologies currently managed via endoscopy include greater trochanteric pain syndrome, tendinopathy and tears of the gluteus medius and minimus, partial and complete hamstring avulsions, and sciatic nerve entrapment. Ischiofemoral impingement may be addressed endoscopically via the deep gluteal space. Orthopaedic surgeons should understand the role and safety of hip arthroscopy in the pediatric population, specifically in the management of slipped capital femoral epiphysis, Legg-Calvé-Perthes disease, and septic arthritis of the hip. The efficacy of hip arthroscopy is limited, and hip arthroscopy is relatively contraindicated in patients with osteoarthritis and hip dysplasia. Complications can occur and likely are underreported in patients who undergo hip arthroscopy. Orthopaedic surgeons should understand practical issues associated with incorporating hip arthroscopy into a practice, including the difficult learning curve associated with hip arthroscopy and the reluctance of some payors to reimburse procedures performed arthroscopically because hip arthroscopy is a relatively new technology.

Unusual Craniofacial Distraction.

A retrospective Institutional Review Board-approved review was performed at the Institute of Reconstructive Plastic Surgery, NYU Langone Medical Center, of patients undergoing craniofacial distraction osteogenesis procedures using the rigid external distractor device between 2000 and 2010. Three particularly challenging cases were identified and are presented here.

Proptosis Correction in Pre-Adolescent Patients With Syndromic Craniosynostosis by Le Fort III Distraction Osteogenesis.

Le Fort III distraction osteogenesis may be indicated in the treatment of syndromic craniosynostosis with severe midface retrusion and proptosis. This study assesses the stability of proptosis correction over 10-years.A retrospective review identified 15 patients with syndromic craniosynostosis treated by Le Fort III distraction prior to age 10 (9 males, 6 females; age 4.9 ±â€Š1.5 years). Untreated, non-craniosynostotic age- and gender-matched controls were obtained from historical growth records. Lateral cephalometric tracings at pre-surgery (T1), immediate (T2), 1 year (T3), 5 years (T4), and 10 years (T5) (n = 11) post-distraction were superimposed using the best-fit of cranial base. Proptosis severity was defined as the horizontal distance between the Ant. Globe cephalometric point and orbital rim landmarks Orbitale and Lat. Orbit.The orbital rim advanced 10.54 ±â€Š3.78 mm (P < 0.001) at Orbitale and 9.73 ±â€Š4.54 mm (P > 0.001) at Lat. Orbit from T1 to T2; Ant. Globe advanced 3.13 ±â€Š3.02 mm (p 0.001). Proptosis decreased 7.41 ±â€Š5.29 mm (P < .001) from Orbitale and 6.60 ±â€Š6.50 mm (p 0.002) from Lat. Orbit. Comparison to controls demonstrated phenotypic correction. In craniosynostotic patients from T2 to T5, the bony orbital rim demonstrated non-significant remodeling posteriorly and inferiorly. Anterior Globe moved 3.79 ±â€Š1.47 mm anteriorly (P < .001), which did not differ significantly from controls. Proptosis increased by 4.18 ±â€Š2.94 mm in craniosynostotic patients from T2 to T5.Le Fort III distraction was stable, with no significant anteroposterior relapse of the maxilla or bony orbit. Phenotypic relapse of proptosis to pre-treatment levels occurred through deficient growth of the midface, surface resorption at the orbital rim, and preservation of normal forward movement of Ant. Globe.

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.

Fabrication and characterization of non-Brownian particle-based crystals.

Particle-based crystals have been explored in the literature for applications in molecular electronics, photonics, sensors, and drug delivery. However, much of the research on these crystals has been focused on particles of nano- and submicrometer dimensions (so-called colloidal crystals) with limited attention directed toward building blocks with dimensions ranging from tens to hundreds of micrometers. This can be attributed, in part, to the fact that the underlying thermal effects in these larger systems typically cannot naturally overcome kinetic barriers at the meso- and macroscales so that many of the methods used for nanoscale particle assembly cannot be directly applied to larger components, as they become kinetically arrested in nonequilibrium states. In this work, ultrasonic agitation is being explored as a means of allowing large, non-Brownian microparticles (18-750 µm) to overcome the kinetic barriers to packing in the creation of close-packed, highly ordered, crystalline structures. In addition, we study how the energy input affects bulk particle behavior and describe several new ways to characterize particle-based crystals made from microparticles.

Preoperative erythropoietin alpha reduces postoperative transfusions in THA and TKA but may not be cost-effective.

BACKGROUND: Preoperative erythropoietin alpha (EPO) has been shown to be effective at reducing postoperative blood transfusions in total hip arthroplasty (THA) and total knee arthroplasty (TKA); however, treatment with EPO is associated with additional costs, and it is not known whether these costs can be justified when weighed against the transfusion reductions achieved in patients who receive the drug. QUESTIONS/PURPOSES: The purpose of this study is to investigate (1) efficacy of preoperative EPO in reducing postoperative transfusions in TKA and THA; (2) whether patients treated with EPO have reduced length of stay or a different discharge disposition; and (3) whether EPO use reduces overall blood management costs. METHODS: Patients undergoing primary THA or TKA over a 10-month period with preoperative hemoglobin<13 g/dL were recommended to be treated preoperatively with EPO. During that time, 80 of 286 (28%) patients met that inclusion criterion and the treating team recommended EPO to all of them; of that group, 24 (30%) opted to take EPO and 56 (70%) opted not to. Patients receiving at least one dose of EPO and those not receiving EPO were compared in terms of transfusion frequency, length of stay and discharge disposition, and overall blood management costs. Demographics, preoperative hemoglobin, and operative blood loss for both groups were similar (p>0.05). No transfusion triggers were used; rather, patients with postoperative hemoglobin<10 mg/dL and who were symptomatic despite fluid boluses were transfused. The clinician responsible for transfusing symptomatic patients was blinded to the patient's EPO treatment status. Costs were defined as direct costs paid or incurred by our institution for EPO, allogeneic blood, and variable costs associated with patient care after THA/TKA. A decision-tree cost analysis was performed using the collected clinical data and cost data collected from our institution; the analysis considered total associated blood management cost for an EPO and a non-EPO strategy with sensitivity analysis of key cost variables. RESULTS: The proportion of patients receiving transfusions was lower in patients who received EPO than in patients who did not (0% [zero of 24] versus 41% [23 of 56]; p<0.001). The mean length of inpatient hospital stay (EPO: 3.0±0.4 versus control: 3.3±0.8 days, p=0.77) and discharge disposition also was not different between the groups. The cost analysis demonstrated that the EPO strategy was more costly compared with no EPO (USD 2632 versus USD 2284) and its cost would need to be less than USD 225/dose for this to change. CONCLUSIONS: EPO reduced the need for postoperative transfusions in high-risk patients undergoing THA and TKA; however, it was not found to be cost-effective in our model. Our model could not consider relatively rare complications of blood transfusions, including disease transmission, deep periprosthetic infections, and transfusion reactions, but if surgeons or patients value avoiding these potential but rare factors highly, this could reasonably influence the decision of whether to use EPO despite our findings that it was not cost-effective. LEVEL OF EVIDENCE: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Femoroacetabular impingement negates the acetabular labral seal during pivoting maneuvers but not gait.

BACKGROUND: Experimental disruption of the labrum has been shown to compromise its sealing function and alter cartilage lubrication. However, it is not known whether pathological changes to the labrum secondary to femoroacetabular impingement (FAI) have a similar impact on labral function. QUESTIONS/PURPOSES: Does damage to the labrum occurring in association with abnormal femoral morphology affect the labral seal? METHODS: Using 10 fresh cadaveric specimens (mean age 50 years, ±8), we measured the capacity of the central compartment of the hip (the iliofemoral joint) to maintain a seal during fluid infusion, which may help elucidate the function of the labrum during weightbearing. Specimens with and without abnormal femoral morphology (six normal-appearing specimens and four whose geometry suggested cam-type FAI) were tested in postures observed during functional activities, including simulations of normal gait, stooping, and pivoting. Each specimen with FAI morphology exhibited secondary damage of the labrum and the adjacent chondral surface, whereas specimens of normal morphology were undamaged. RESULTS: Average peak central compartment pressure was reduced during pivoting for specimens with the presence of labral damage secondary to FAI. When placed in pivoting positions, hips with FAI maintained lower fluid pressures within the central compartment compared with intact specimens (15±3 versus 42±8 kPa, respectively; effect size: 1.08 [-0.36 to 2.31]; p=0.007). No differences in peak pressure were observed between groups (FAI versus normal) for postures simulating either gait (21±6 versus 22±4 kPa; p=0.902) or stooping (9±2 versus 8±3 kPa; p=0.775) with the numbers available. CONCLUSIONS: The acetabular seal, quantified by the maximum intraarticular pressure, was reduced during pivoting; however, the seal was maintained during simulated gait and stooping. CLINICAL RELEVANCE: Because degeneration is progressive with repetitive impingement, loss of the labral seal starts to be seen during pivoting and may progress from there, but in this small-sample cadaver study that evaluated specimens in middle adulthood, the seal remains intact during simulated gait and stooping. Our study suggests that labral damage secondary to cam-type FAI may reduce the ability of the labral to provide an adequate seal of the central compartment of the hip during loading; however, the extent to which this is affected requires further investigation.

Use of MR arthrography in detecting tears of the ligamentum teres with arthroscopic correlation.

OBJECTIVE: To demonstrate the normal appearance of the ligamentum teres on MR arthrography (MRA) and evaluate the accuracy of MRA in detecting ligamentum teres tears with arthroscopic correlation. MATERIALS AND METHODS: Institutional Review Board approval was obtained with a waiver for informed consent because of the retrospective study design. A total of 165 cases in 159 patients (111 females, 48 males; mean age 41 ± 12 years) who underwent both MRA and hip arthroscopy were evaluated for appearance of the ligamentum teres, including the size, number of bundles, and ligamentum teres tears. Marrow edema of the fovea capitis adjacent to the ligamentum teres insertion and the presence of hip plicae were also recorded. RESULTS: The mean thickness and length of the ligamentum teres were 3.5 ± 1.5 mm and 25.2 ± 3.8 mm, respectively. Sensitivity, specificity, positive and negative predictive value, and accuracy of MRA for the detection of ligamentum teres tears were 78, 97, 74, 97, and 95%, respectively. CONCLUSION: MRA is an accurate method to evaluate the normal morphology and to detect tears of the ligamentum teres.

Cartilage Status at Time of Arthroscopy Predicts Failure in Patients With Hip Dysplasia.

The purpose of our study was to determine whether chondral damage at the time of arthroscopy predicted conversion to THA in patients with dysplasia. We identified 166 patients with dysplasia who underwent hip arthroscopy. Forty-seven went on to receive THA. The articular cartilage of three regions of the acetabulum and femoral head were assessed for signs of chondral damage (absent, mild, or severe]). A stepwise multivariable logistic regression analysis revealed mild damage on the posterior femoral head (P=0.001) and severe damage on the anterior acetabulum (P=0.007) made a significant contribution to the predictor. The presence of mild posterior femoral head chondral changes was indicative of more global cartilage damage in this series of patients. Our findings show that chondral damage on the posterior femoral head and anterior acetabulum is a strong predictor of ultimate conversion to THA in dysplastic patients.

Unilateral Craniofacial Microsomia: Unrecognized Cause of Pediatric Obstructive Sleep Apnea.

Bilateral craniofacial microsomia causes obstructive sleep apnea (OSA). We hypothesize that unilateral craniofacial microsomia (UCFM) is an underappreciated cause of OSA. The records of all pediatric UCFM patients from 1990 to 2010 were reviewed; only complete records were included in the study. UCFM patients with OSA (apnea hypopnea index >1/hr) were compared to UCFM patients without OSA. Univariate and multivariate Fisher and χ(2) tests were performed. Of the 62 UCFM patients, 7 (11.3%) had OSA. All OSA patients had Pruzansky IIB or III mandibles. OSA patients presented with snoring (71.4%), failure to thrive (FTT) (57.1%), and chronic respiratory infections (42.8%). Snoring (P < 0.001), Goldenhar syndrome (P = 0.001), and FTT (P = 0.004) were significantly associated with OSA, but race, obesity, clefts, respiratory anomalies, adenotonsillar hypertrophy, and laterality were not. The prevalence of OSA in UCFM patients is up to 10 times greater than in the general population. Snoring, Goldenhar syndrome, and FTT are significantly associated with the presence of OSA.

Non-Brownian particle-based materials with microscale and nanoscale hierarchy.

Colloidal crystals are interesting materials owing to their customizable photonic properties, high surface area, and analogy to chemical structures. The flexibility of these materials has been greatly enhanced through mixing particles with varying sizes, compositions, and surface charges. In this way, distinctive patterns or analogies to chemical stoichiometries are produced; however, to date, this body of research is limited to particles with nanoscale dimensions. A simple method is now presented for bottom-up assembly of non-Brownian particle mixtures to create a new class of hierarchically-ordered materials that mimic those found in nature (both in pore distribution as well as stoichiometry). Additionally, these crystals serve as a template to create particle-based inverted crystalline structures with customizable properties.

Accurate amorphous silica surface models from first-principles thermodynamics of surface dehydroxylation.

Accurate atomically detailed models of amorphous materials have been elusive to-date due to limitations in both experimental data and computational methods. We present an approach for constructing atomistic models of amorphous silica surfaces encountered in many industrial applications (such as catalytic support materials). We have used a combination of classical molecular modeling and density functional theory calculations to develop models having predictive capabilities. Our approach provides accurate surface models for a range of temperatures as measured by the thermodynamics of surface dehydroxylation. We find that a surprisingly small model of an amorphous silica surface can accurately represent the physics and chemistry of real surfaces as demonstrated by direct experimental validation using macroscopic measurements of the silanol number and type as a function of temperature. Beyond accurately predicting the experimentally observed trends in silanol numbers and types, the model also allows new insights into the dehydroxylation of amorphous silica surfaces. Our formalism is transferrable and provides an approach to generating accurate models of other amorphous materials.

Hip pain in the young, active patient: surgical strategies.

Hip disorders in young patients likely exist as a spectrum of prearthritic and arthritic conditions. With the increasing recognition of these disorders, surgical options are being popularized and more patients are being treated at a younger age. Hip surgeons must develop a careful set of evidenced-based indications and follow surgical outcomes in a rigorous, scientific manner. Hip arthroscopy can be used to successfully treat some hip disorders, including labral tears, with or without femoroacetabular impingement, resulting in mechanical symptoms. Long-term outcomes after arthroscopy are determined by the condition of the cartilage at the time of surgery. Patients with preoperative radiographic evidence of moderate to severe arthritis have poor outcomes when treated with arthroscopy. Open joint preservation procedures (including periacetabular osteotomy and surgical hip dislocation with osteochondroplasty) can be done in the absence of substantial arthritis to treat hip dysplasia, femoroacetabular impingement, and related conditions. The results of these procedures are good in appropriately selected patients at short-term to midterm follow-ups. In the presence of severe arthritis, joint replacement is the treatment of choice. Total hip arthroplasty using uncemented acetabular and femoral fixation provides reliable osseointegration; however, long-term results in young patients have historically been compromised by bearing surface wear, osteolysis, and component loosening. Contemporary, highly cross-linked polyethylene and ceramic-on-ceramic bearings have durable results, low complication rates, and offer the potential of long-term survivorship in this high-demand population. In general, metal-on-metal implants have higher complication rates versus other bearing surface options and should be avoided. The best results of hip resurfacing are seen in men younger than 55 years with large femoral head sizes. Although implant survivorship is comparable to that of total hip arthroplasty, the sequelae of metal wear debris continue to cause concern.

Correlation of magnetic resonance arthrography with revision hip arthroscopy.

BACKGROUND: Arthroscopic approaches for the diagnosis and treatment of hip disorders are well established; however, there are limited data regarding revision hip arthroscopy. There have been several studies evaluating the findings of MR arthrography with primary hip arthroscopy, but to our knowledge, no study has evaluated the diagnostic value of MR arthrography before revision hip arthroscopy. QUESTIONS/PURPOSES: We obtained sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of MR arthrography to detect labral lesions, chondral lesions and loose bodies before revision hip arthroscopy. METHODS: We performed a single-surgeon, retrospective review of 70 revision hip arthroscopies (62 patients) and assessed the association between MR arthrography findings and intraoperative findings. There were 43 females and 19 males with a mean age of 36 years (range, 17-59 years). Radiographic interpretation was performed by one of four fellowship-trained musculoskeletal radiologists at three institutions, who had at least 5 years of experience. Radiographic findings were compared with surgical findings by one of the authors for calculation of sensitivity, specificity, PPV, and NPV. RESULTS: The sensitivity, specificity, PPV, and NPV of MR arthrography for detecting labral tears were 82%, 70%, 94%, and 39%, respectively. The sensitivity, specificity, PPV, and NPV of MR arthrography for detecting chondral damage were 65%, 90%, 94%, and 50%, respectively. The sensitivity, specificity, PPV, and NPV of MR arthrography for detecting loose bodies were 33%, 100%, 100%, and 88%, respectively. CONCLUSIONS: Our study showed the utility of MR arthrography to assist in the diagnosis and treatment of patients with ongoing or recurrent symptoms who have had prior hip arthroscopy. Our data show that MR arthrography is superior at ruling in, rather than ruling out, labral lesions, chondral lesions, and loose bodies, as there were studies interpreted as normal which in fact showed disorders.