The iliac pillar - Definition of an osseous fixation pathway for internal and external fixation.

BACKGROUND: Increasing numbers of unstable pelvic ring fractures, due to the ongoing demographic change and improvements in the rescue of high-energy traumatic events, are challenging trauma and orthopedic surgeons. While initial installation of an external fixation device is often necessary, placement of iliac crest pins can be difficult due to the complex osteology of the ilium. HYPOTHESIS: We aim to analyze (1) the length, localization and angulation of the iliac pillar and (2) to define the dimensions of the surgical corridor for a better understanding of pin entry point and trajectory, thus preventing shortcomings in anterior external fixation of pelvic ring injuries. METHODS: Twenty hemipelvises from 10 fresh-frozen cadaveric torsos (3 female, 7 males; mean age 80.2 years) were harvested. The following measurements were taken with digital calipers: Location of the iliac pillar in relation to the anterior superior iliac spine and to the acetabulum roof, mean length and diameter of the iliac pillar, maximum diameter of the iliac pillar. In addition we measured the width of the different bone layers. RESULTS: The mean length of the hourglass shaped iliac pillar was 107.04mm with a mean width of 17.0mm (min. 15.1; max. 19.2). The mean distance to the anterior superior iliac spine was 69.00mm (min. 64.8; max. 73.4). The mean maximum width of the iliac pillar was 12.16mm (min. 9.4; max. 13.8). Caudally the line describing the iliac pillar intercepts the cranial acetabular rim at 12 o'clock. The smallest mean diameter of the cancellous bone was 7.5mm±2.0. CONCLUSION: The iliac pillar is part of the complex osteology of the human pelvis. A cohesive description of its location and dimensions has been lacking. Successful treatment of pelvic fracture depends on an optimal preoperative planning, accurate overall reduction, and stable fixation. We described the origin and angulation to provide a good bone stock for external fixation pin and the width of the different bone layers. This study therefore contributes by facilitating a thorough understanding of pelvic osteology and describing the location and dimensions of an optimal osseous pathway. LEVEL OF EVIDENCE: Anatomical descriptive study.

The impact of the 30 most cited articles on hip arthroscopy: what is the subject matter?

The purpose of this study was to identify the 30 most cited articles on hip arthroscopy and discuss their influence on recent surgical treatment. Due to advancements in hip arthroscopy, there is a widening spectrum of diagnostic and treatment indications. The purpose of this study was to identify the 30 most cited articles on hip arthroscopy and discuss their influence on contemporary surgical treatment. The Thomson Reuters Web of Science was used to identify the 30 most cited studies on hip arthroscopy between 1900 and 2018. These 30 articles generated 6152 citations with an average of 205.07 citations per item. Number of citations ranged from 146 to 461. Twenty-five out of the 30 papers were clinical cohort studies with a level of evidence between III and IV, encompassing 4348 patients. Four studies were reviewed (one including a technical note) and one a case report. We were able to identify the 30 most cited articles in the field of hip arthroscopy. Most articles were reported in high-impact journals, but reported small sample sizes in a retrospective setting. Prospective multi-arm cohort trials or randomized clinical trials represent opportunities for future studies.

Comparison of Intraoperative Fluoroscopic Dunn View With Magnetic Resonance Imaging to Determine Femoral Version.

PURPOSE: To compare femoral version measured with a fluoroscopic Dunn view taken at the time of hip arthroscopy with values derived from axial magnetic resonance imaging (MRI) scans. METHODS: Of 159 hip arthroscopies performed from January 2014 through March 2015, 50 patients had magnetic resonance imaging (MRI) scans with a protocol that incorporates femoral version analysis. Dunn views are performed as a routine part of the preoperative fluoroscopic examination at the time of arthroscopy. Femoral version was measured from the fluoroscopic views and compared with values calculated from axial MRI images. The measurements were compared with a paired t test for difference in means, the intraclass correlation coefficient (ICC) for reliability, and the limits of agreement method of Bland and Altman. RESULTS: There was a very small but statistically significant difference between the measurement on fluoroscopic Dunn view and the value on axial MRI (mean difference, 1.4°, P = .03). The ICC was 0.809 (P < .0001), indicating substantial agreement. By the Bland and Altman method, the 95% limits of agreement for fluoroscopic versus MRI measurement were -7.6 to 10.4, with no significant difference in variance by Pitman test (P = .526). CONCLUSIONS: With careful attention to technique, the fluoroscopically simulated Dunn view can be used to measure femoral version with acceptable accuracy and obviates the need for repeat 3-dimensional imaging for patients who already have an MRI scan without version analysis. LEVEL OF EVIDENCE: Level II, testing of previously developed diagnostic criteria with a gold standard.

Surgical innovation and safety: femoroacetabular impingement and the IDEAL collaborative framework.

Operative treatment of femoroacetabular impingement (FAI) is a relatively new, yet rapidly expanding surgical innovation. Although the practice of surgery is inherently innovative, there is no clear distinction between minor technical variation and true modification that warrants testing. This raises important questions about how new procedures should be evaluated before being broadly disseminated. The IDEAL Collaborative is a consortium that promotes safe and responsible translation of research into clinical practice. The collaborative has delineated the typical stages of evolution of new interventional technologies, and the type of study designs appropriate for each stage. This report examines the surgical treatment of FAI as a case study of the IDEAL framework and discusses both missed and future opportunities for critical assessment.

Femoral cam deformity due to anterior capsular force: A theoretical model with MRI and cadaveric correlation.

BACKGROUND: Cam deformity is associated with epiphyseal extension onto the anterosuperior femoral head-neck before physeal closure. A century ago, anatomists speculated that this femoral prominence acts as a pulley bar to withstand capsular compression in hip extension with pressure concentrated where the zona orbicularis (ZO) joins the iliofemoral ligament (IFL). An animal model has shown that growth plates deflect laterally and distally when exposed to forces perpendicular to growth. These observations raise the question of whether capsular pressure against the epiphysis can stimulate cam formation. PURPOSE: The purposes are to measure: (1) the distance from the ZO/IFL confluence to the maximal epiphyseal extension (MEE) and cam apex; and (2) acetabular depth at this location, since less coverage increases capsular contact on the physis. METHODS: MRI scans of 39 subjects (47 hips) were measured. Acetabular depth was compared between those with and without a cam deformity. Secondarily, anatomic findings were correlated on a cadaveric specimen. RESULTS: The cam apex and MEE were adjacent to the ZO/IFL confluence in all subjects (mean, 6.3 mm). Controlling for sex, acetabular depth was less (12.5%, p = 0.012) in the group with cam deformity. Contact points were confirmed in the specimen. CONCLUSIONS: The cam apex and MEE occur at the ZO/IFL confluence in the thickest region of the anterosuperior capsule and vary with acetabular depth. This supports a theoretical model postulating that capsular forces against an immature epiphysis may induce cam formation, particularly in individuals who repetitively tension the anterior capsule.

A sodium channel variant in Aedes aegypti as a candidate pathogen sensor for viral-associated molecular patterns.

Recent work demonstrated that a splice variant of a human macrophage voltage-gated sodium channel expressed on endosomes acts as an intracellular sensor for dsRNA, a viral-associated molecular pattern. Here our goal was to identify a candidate gene in a clinically relevant invertebrate model with related cellular and pattern recognition properties. The para gene in drosophila and other insects encodes voltage-gated sodium channels with similar electrophysiological properties to those found in vertebrate excitable membranes. A database search revealed that the AAEL006019 gene in Aedes aegypti, the yellow fever mosquito, encodes a voltage-gated sodium channel that is distinct from genes that encode para-like sodium channels. As compared to para-like channels, the protein products from this gene have deletions in the N-terminus and in the DII-DIII linker region. When over-expressed in an Aedes aegypti cell line, CCL-125, the AAEL006019 channel demonstrated cytoplasmic expression on vesicular-like organelles. Electrophysiologic analysis revealed that the channel mediates small inward currents that are enhanced by synthetic mimics of viral-derived ssRNA, R848 and ORN02, but not the dsRNA mimic, poly I:C. R848 treatment of CCL-125 cells that express high levels of the channels led to increased expression of RelA and Ago2, two mediators of insect innate immunity. These results suggest that the AAEL006019 channel acts as an intracellular pathogen sensor for ssRNA molecular patterns.

Is acetabular osteoplasty always required in mixed impingement?

BACKGROUND: Mixed femoroacetabular impingement (FAI) is typically managed with both femoral and acetabular rim osteoplasties, but it has not been reported if the rim osteoplasty is always required. HYPOTHESIS/PURPOSE: We hypothesized that mixed FAI managed by femoral or combined femoral and acetabular osteoplasties will both attain satisfactory clinical results, provided intraoperative impingement-free functional motion is attained. METHODS: We retrospectively reviewed 30 hips (23 patients, mean age at surgery 24.3 years, mean follow-up time 1.6 years) with mixed FAI who underwent surgical dislocation of the hip and had femoral osteochondroplasty with rim trim (RT, n = 21) or no rim trim (NRT, n = 9). Physical examination results and Western Ontario and McMaster Universities Osteoarthritis (WOMAC) scores were evaluated. RESULTS: Mean (± SD) WOMAC pain scores improved from 6.56 (± 2.96) to 2.33 (± 3.64) in the NRT group (p = .002) and from 6.86 (± 4.15) to 3.86 (± 3.95) in the RT group (p = .014). Function improved in both groups, but the difference was significant only for the NRT group (p < .001). Over 50 % of patients in both groups had resolution of impingement sign. Internal rotation increased from 8.6° (± 11.8) to 20.0° (± 10.4) in the NRT group (p = .043) and from 4.0° (± 12.1) to 18.6° (± 14.0) in the RT group (p < .001). Both groups had increased flexion post-operatively to normal range, but the change was only significant for the RT group (p = .02). Both groups had insignificant decreases in external rotation. CONCLUSION: Satisfactory clinical outcomes were seen in hips with mixed impingement, regardless of whether RT was performed, provided impingement-free functional motion was attained and no severe cartilage damage was seen.

Human macrophage SCN5A activates an innate immune signaling pathway for antiviral host defense.

Pattern recognition receptors contain a binding domain for pathogen-associated molecular patterns coupled to a signaling domain that regulates transcription of host immune response genes. Here, a novel mechanism that links pathogen recognition to channel activation and downstream signaling is proposed. We demonstrate that an intracellular sodium channel variant, human macrophage SCN5A, initiates signaling and transcription through a calcium-dependent isoform of adenylate cyclase, ADCY8, and the transcription factor, ATF2. Pharmacological stimulation with a channel agonist or treatment with cytoplasmic poly(I:C), a mimic of viral dsRNA, activates this pathway to regulate expression of SP100-related genes and interferon ß. Electrophysiological analysis reveals that the SCN5A variant mediates nonselective outward currents and a small, but detectable, inward current. Intracellular poly(I:C) markedly augments an inward voltage-sensitive sodium current and inhibits the outward nonselective current. These results suggest human macrophage SCN5A initiates signaling in an innate immune pathway relevant to antiviral host defense. It is postulated that SCN5A is a novel pathogen sensor and that this pathway represents a channel activation-dependent mechanism of transcriptional regulation.

Clinical outcomes assessment in clinical trials to assess treatment of femoroacetabular impingement: use of patient-reported outcome measures.

Patient-reported outcome measures are an important component of outcomes assessment in clinical trials to assess the treatment of femoroacetabular impingement (FAI). This review of disease-specific measures and instruments used to assess the generic quality of life and physical activity levels of patients with FAI found no conclusive evidence to support a single disease-specific questionnaire. Using a systematic review of study methodology, the Copenhagen Hip and Groin Outcome Score and the 33-item International Hip Outcome Tool scored the best. Nevertheless, both of these instruments were developed recently and have not been established in the literature. Although currently used generic and activity-level measures have limitations, as well, they should be considered, depending on the specific goals of the study. Additional research is needed to assess the properties of these measures fully when used to evaluate patients with FAI.

Predictors of blood loss and haematocrit after periacetabular osteotomy.

BACKGROUND: Acetabular dysplasia is a common cause of hip pain that can lead to osteoarthritis. Periacetabular osteotomy (PAO) is an effective procedure to treat symptomatic dysplasia in properly selected patients. PURPOSE: This study aims to determine patient or perioperative variables that are predictive of blood loss (EBL) and postoperative haematocrit (HCT) with PAO. PATIENTS AND METHODS: Between March 2009 and October 2011, 169 PAOs in 141 patients were performed. Associations with EBL (log-transformed) and lowest postoperative haematocrit (post-HCT, <26 vs. ≥26) were assessed by regression analysis, adjusting for surgeon and for within-patient correlations. RESULTS: Geometric mean EBL was 925 mL (range 200-3900 mL; 95% CI: 851.3, 1005.1). There was 11.1% greater blood loss per hour of surgery (p = 0.02). Preoperative HCT averaged (±SD) 36.1 (±3.3). In 119 cases (71%), the post-HCT was <26. Lower preoperative HCT correlated with post-HCT <26 (p<0.001); the median ratio of the lowest postoperative HCT to the preoperative HCT was 0.687 (5th, 95th percentiles: 0.538, 0.781). Age, body mass index (BMI), arthrotomy, and anaesthesia-type showed no association with EBL or post-HCT. CONCLUSIONS: Longer duration of surgery correlated with increased blood loss during PAO. Current guidelines recommend considering transfusion at haemoglobin ≤8 g/dL for postoperative patients. The median nadir post-HCT was 31% lower than the preoperative value, a ratio that may help determine the need for preoperative blood donation. This information facilitates future investigation of blood management with PAO.

Patient selection for rotational pelvic osteotomy.

Acetabular dysplasia is a common cause of hip pain and can lead to premature osteoarthritis. Preserving the native hip is the first choice in young, active patients with minimal arthrosis. Techniques in rotational pelvic osteotomy have evolved to offer long-term benefits, but appropriate patient selection is an important determinant of success. Applying a stepwise approach when evaluating adult patients with acetabular dysplasia and understanding current outcomes and predictive data will allow the orthopaedic surgeon to choose appropriate candidates for pelvic osteotomy.

Alternatives to periacetabular osteotomy for adult acetabular dysplasia.

Pelvic osteotomy is a powerful tool for improving the mechanical forces in a dysplastic hip. Multiple techniques have evolved over the past 70 years to treat the symptomatic adult patient with acetabular dysplasia. Although the Bernese periacetabular osteotomy is commonly used in the United States, several other types of osteotomies, including the rotational (spheric or dial) acetabular osteotomy, the triple pelvic osteotomy, and the Chiari medial displacement pelvic osteotomy, have demonstrated good success and are used in many parts of the world.

Demographic differences in adolescent-diagnosed and adult-diagnosed acetabular dysplasia compared with infantile developmental dysplasia of the hip.

BACKGROUND: Acetabular dysplasia is a common cause of hip pain that can lead to premature osteoarthritis. This study explores whether demographic characteristics of patients diagnosed with acetabular dysplasia in adolescence and adulthood [adult-diagnosed dysplasia (AD)] differ from those who are diagnosed with developmental dysplasia of the hip (DDH) in infancy. METHODS: Database review identified 633 patients undergoing periacetabular osteotomy for dysplasia from August 1991 to January 2008. Excluding patients with syndromal conditions and 80 lacking contact information, 421 patients received a questionnaire regarding birth and family history; 324 (70.3%) completed the survey. Thirteen were excluded because of unrelated hip conditions, leaving 311 patients for analysis. RESULTS: Respondents were divided into 2 groups according to whether they had a history of DDH in infancy (102 patients) or were diagnosed in adolescence/adulthood (209 patients). Statistically significant differences (P < 0.05) were found in sex distribution (female: DDH = 98.0%, AD = 88.0%), affected limb (left hip: DDH = 33.3%, AD = 19.1%), bilaterality (DDH = 45.1%, AD = 61.2%), and breech presentation (DDH = 25.3%, AD = 9.4%). Over 50% of all the respondents had a family history of hip disease; over 40% were first-order relatives. First-order family members of patients with AD had a higher incidence of hip replacement by the age of 65 (50.0% vs. 22.7%). Patients with DDH were more likely to have first-order family members with DDH (59.0% vs. 15.8%). CONCLUSIONS: This study confirms demographic differences between patients diagnosed with hip dysplasia in infancy versus adolescence/adulthood and supports the hypothesis that these represent distinct forms of dysplasia. In both, there is a familial tendency toward hip disease with a higher incidence of arthroplasty in the AD group's family members and higher frequency of infantile dysplasia in the DDH group's family members. CLINICAL RELEVANCE: Infantile DDH is diagnosed with neonatal examination and patients are routinely followed into adolescence. Adolescent/adult AD is not detected until symptoms develop. Further study is needed to determine whether younger family members of patients with hip osteoarthritis should be screened to detect potentially at-risk hips.

Case reports: acetabular damage after mild slipped capital femoral epiphysis.

BACKGROUND: Slipped capital femoral epiphysis (SCFE) is a common hip problem in adolescents that results in a cam-type femoroacetabular impingement (FAI) deformity. Although the treatment for mild (slip angle of 0°-30°) and moderate (slip angle of 31°-60°) SCFE has historically been in situ fixation, recent studies have demonstrated impingement-related articular damage, irrespective of slip severity. Our series confirms previous reports that acetabular chondral injury occurs in mild to low-moderate (slip angle of ≤ 40°) SCFE. CASE DESCRIPTION: We retrospectively reviewed five patients who underwent arthroscopy and femoral osteoplasty within 18 months after in situ stabilization. All had labral and/or acetabular damage. LITERATURE REVIEW: Osteoarthritis rates after SCFE range from 24% to 92% at 11 to 28 years, depending on how osteoarthritis is defined. Long-term followup suggests patients have acceptable outcomes, but these studies are limited by heterogeneity and a ceiling effect from the instruments used to assess function. Although the femoral deformity remodels, it is unclear what secondary changes occur in the acetabulum. Recent investigations suggest patients are functionally limited after SCFE owing to FAI compared with controls. MRI findings and surgical reports document impingement-related joint damage after SCFE, even in the absence of symptoms. Based on this, some advocate timely correction of the cam deformity inherent in SCFE. PURPOSES AND CLINICAL RELEVANCE: Further study is warranted to determine whether immediate osteoplasty after in situ fixation of mild SCFE is beneficial to limit articular damage and improve long-term outcomes.

Imaging hip dysplasia in the skeletally mature.

Hip disorders in the young adult manifest along a continuum that ranges from an excessively constrained, impinging joint, to an overly shallow, unstable hip. Knowledge of simple measures on plain radiographs can aid in efficient and accurate identification of mechanically compromised hips that may be at risk for premature OA. Improvements in joint-preserving surgery have shown promise in delaying or preventing progression of articular degeneration; thus, timely diagnosis is important. Once a diagnosis is established, specialized imaging can be individualized to supplement surgical planning, assess the degree of cartilage damage, and facilitate discussion regarding the prognosis of hip-preserving procedures.

Fluoroscopic demonstration of femoroacetabular impingement during hip arthroscopy.

Femoroacetabular impingement is a cause of hip pain that in selected cases can be treated by removal of impinging bone (osteoplasty). No absolute parameters for osteoplasty exist. We present a technique for dynamic evaluation of bony impingement and control of arthroscopic osteoplasty using intraoperative fluoroscopy. With the patient supine on a fracture table, the C-arm is positioned between the legs. Femoral anteversion is measured with the C-arm vertical and the hip flexed 90° (Dunn view). The C-arm is then tilted back 25° from vertical to create a profile view of the anterior rim, and the hip is flexed under fluoroscopy to find the location of maximum head/neck deformity. Because the distance between rim and neck is apparent, a spot view in that position is used to plan the osteoplasties. Impingement is demonstrated by forced internal rotation and is obvious as bony contact, movement of the pelvis, or joint subluxation. Osteoplasty of the neck is performed with the hip extended and the C-arm tilted to reproduce the view of the maximum neck deformity. The dynamic examination is repeated to confirm adequacy of the osteoplasty and improvement in internal rotation. Hip deformities could be efficiently identified and individually corrected.