The Acetabular Wall Index Is Associated with Long-term Conversion to THA after PAO.

BACKGROUND: Periacetabular osteotomy (PAO) has been shown to be a valuable option for delaying the onset of osteoarthritis in patients with hip dysplasia. Published studies at 30 years of follow-up found that postoperative anterior overcoverage and posterior undercoverage were associated with early conversion to THA. The anterior and posterior wall indices are practical tools for assessing AP coverage on standard AP radiographs of the pelvis pre-, intra-, and postoperatively. However, no study that we know of has evaluated the relationship between the postoperative anterior and posterior wall indices and survivorship free from arthroplasty. QUESTIONS/PURPOSES: In a study including patients after PAO for developmental dysplasia of the hip (DDH), we evaluated whether the acetabular wall index is associated with conversion to THA in the long-term after PAO. We asked: (1) Is an abnormal postoperative anterior wall index associated with conversion to THA after PAO? (2) Is an abnormal postoperative posterior wall index associated with conversion to THA after PAO? (3) Are there other factors associated with joint replacement after PAO? METHODS: This retrospective study involved pooling data of PAO for DDH from two previously published sources. The first series (1984-1987) comprised the very first 75 PAOs for symptomatic DDH performed at the inventor's institution. The second (1997-2000) comprised a series of PAOs for symptomatic DDH completed at the same institution 10 years later. No patient was lost to follow-up. Fifty hips (44 patients) were excluded for predefined reasons (previous surgery, substantial femoral pathomorphologies, poor-quality radiographs), leaving 115 hips (102 patients, mean age 29 ± 11 years, 28% male) for analysis with a mean follow-up of 22 ± 6 years. One observer not involved in patient treatment digitally measured the anterior and posterior wall indices on postoperative AP pelvic radiographs of all patients. All patients were contacted by mail or telephone to confirm any conversion to THA and the timing of that procedure relative to the index procedure. We performed univariate and multivariate Cox regression analyses using conversion to THA as our endpoint to determine whether the anterior and posterior wall indices are associated with prosthetic replacement in the long-term after PAO. Thirty-one percent (36 of 115) of hips were converted to THA within a mean of 15 ± 7 years until failure. The mean follow-up duration of the remaining patients was 22 ± 6 years. RESULTS: A deficient anterior wall index was associated with conversion THA in the long-term after PAO (adjusted hazard ratio 10 [95% CI 3.6 to 27.9]; p < 0.001). Although observed in the univariate analysis, we could not find a multivariate association between the posterior wall index and a higher conversion rate to THA. Grade 0 Tönnis osteoarthritis was associated with joint preservation (adjusted HR 0.2 [95% CI 0.07 to 0.47]; p = 0.005). Tönnis osteoarthritis Grades 2 and 3 were associated with conversion to THA (adjusted HR 2.3 [95% CI 0.9 to 5.7]; p = 0.08). CONCLUSION: A deficient anterior wall index is associated with a decreased survivorship of the native hip in the long-term after PAO. Intraoperatively, in addition to following established radiographical guidelines, the acetabular wall indices should be measured systematically to ascertain optimal acetabular fragment version to increase the likelihood of reconstructive survival after PAO for DDH. LEVEL OF EVIDENCE: Level III, therapeutic study.

Medialization of the Hip's Center with Periacetabular Osteotomy: Validation of Assessment with Plain Radiographs.

BACKGROUND: Periacetabular osteotomy (PAO) increases acetabular coverage of the femoral head and medializes the hip's center, restoring normal joint biomechanics. Past studies have reported data regarding the degree of medialization achieved by PAO, but measurement of medialization has never been validated through a comparison of imaging modalities or measurement techniques. The ilioischial line appears to be altered by PAO and may be better visualized at the level of the inferior one-third of the femoral head, thus, an alternative method of measuring medialization that begins at the inferior one-third of the femoral head may be beneficial. QUESTIONS/PURPOSES: (1) What is the true amount and variability of medialization of the hip's center that is achieved with PAO? (2) Which radiographic factors (such as lateral center-edge angle [LCEA] and acetabular inclination [AI]) correlate with the degree of medialization achieved? (3) Does measurement of medialization on plain radiographs at the center of the femoral head (traditional method) or inferior one-third of the femoral head (alternative method) better correlate with true medialization? (4) Are intraoperative fluoroscopy images different than postoperative radiographs for measuring hip medialization? METHODS: We performed a retrospective study using a previously established cohort of patients who underwent low-dose CT after PAO. Inclusion criteria for this study included PAO as indicated for symptomatic acetabular dysplasia, preoperative CT scan, and follow-up between 9 months and 5 years. A total of 333 patients who underwent PAO from February 2009 to July 2018 met these criteria. Additionally, only patients who were between 16 and 50 years old at the time of surgery were included. Exclusion criteria included prior ipsilateral surgery, femoroacetabular impingement (FAI), pregnancy, neuromuscular disorder, Perthes-like deformity, inadequate preoperative CT, and inability to participate. Thirty-nine hips in 39 patients were included in the final study group; 87% (34 of 39) were in female patients and 13% (5 of 39 hips) were in male patients. The median (range) age at the time of surgery was 27 years (16 to 49). Low-dose CT images were obtained preoperatively and at the time of enrollment postoperatively; we also obtained preoperative and postoperative radiographs and intraoperative fluoroscopic images. The LCEA and AI were assessed on plain radiographs. Hip medialization was assessed on all imaging modalities by an independent, blinded assessor. On plain radiographs, the traditional and alternative methods of measuring hip medialization were used. Subgroups of good and fair radiographs, which were determined by the amount of pelvic rotation that was visible, were used for subgroup analyses. To answer our first question, medialization of all hips was assessed via measurements made on three-dimensional (3-D) CT hip reconstruction models. For our second question, Pearson correlation coefficients, one-way ANOVA, and the Student t-test were calculated to assess the correlation between radiographic parameters (such as LCEA and AI) and the amount of medialization achieved. For our third question, statistical analyses were performed that included a linear regression analysis to determine the correlation between the two radiographic methods of measuring medialization and the true medialization on CT using Pearson correlation coefficients, as well as 95% confidence intervals and standard error of the estimate. For our fourth question, Pearson correlation coefficients were calculated to determine whether using intraoperative fluoroscopy to make medialization measurements differs from measurements made on radiographs. RESULTS: The true amount of medialization of the hip center achieved by PAO in our study as assessed by reference-standard CT measurements was 4 ± 3 mm; 46% (18 of 39 hips) were medialized 0 to 5 mm, 36% (14 hips) were medialized 5 to 10 mm, and 5% (2 hips) were medialized greater than 10 mm. Thirteen percent (5 hips) were lateralized (medialized < 0 mm). There were small differences in medialization between LCEA subgroups (6 ± 3 mm for an LCEA of ≤ 15°, 4 ± 4 mm for an LCEA between 15° and 20°, and 2 ± 3 mm for an LCEA of 20° to 25° [p = 0.04]). Hips with AI ≥ 15° (6 ± 3 mm) achieved greater amounts of medialization than did hips with AI of < 15° (2 ± 3 mm; p < 0.001). Measurement of medialization on plain radiographs at the center of the femoral head (traditional method) had a weaker correlation than using the inferior one-third of the femoral head (alternative method) when compared with CT scan measurements, which were used as the reference standard. The traditional method was not correlated across all radiographs or only good radiographs (r = 0.16 [95% CI -0.17 to 0.45]; p = 0.34 and r = 0.26 [95% CI -0.06 to 0.53]; p = 0.30), whereas the alternative method had strong and very strong correlations when assessed across all radiographs and only good radiographs, respectively (r = 0.71 [95% CI 0.51 to 0.84]; p < 0.001 and r = 0.80 [95% CI 0.64 to 0.89]; p < 0.001). Measurements of hip medialization made on intraoperative fluoroscopic images were not found to be different than measurements made on postoperative radiographs (r = 0.85; p < 0.001 across all hips and r = 0.90; p < 0.001 across only good radiographs). CONCLUSION: Using measurements made on preoperative and postoperative CT, the current study demonstrates a mean true medialization achieved by PAO of 4 mm but with substantial variability. The traditional method of measuring medialization at the center of the femoral head may not be accurate; the alternate method of measuring medialization at the lower one-third of the femoral head is a superior way of assessing the hip center's location. We suggest transitioning to using this alternative method to obtain the best clinical and research data, with the realization that both methods using plain radiography appear to underestimate the true amount of medialization achieved with PAO. Lastly, this study provides evidence that the hip center's location and medialization can be accurately assessed intraoperatively using fluoroscopy. LEVEL OF EVIDENCE: Level III, diagnostic study.

What Are the Early Outcomes of True Reverse Periacetabular Osteotomy for Symptomatic Hip Overcoverage?

BACKGROUND: Acetabular overcoverage is associated with pincer-type femoroacetabular impingement (FAI). A subtype of acetabular overcoverage is caused by a deep acetabulum with a negatively tilted acetabular roof, in which acetabular reorientation may be a preferable alternative to rim trimming to uncover the femoral head. We introduced the true reverse periacetabular osteotomy (PAO) in 2003, which in contrast to an anteverting PAO, also flexes and abducts the acetabulum relative to the intact ilium to decrease anterior and lateral femoral head coverage and correct negative tilt of the acetabular roof. To our knowledge, the clinical results of the true reverse PAO have not been evaluated. QUESTIONS/PURPOSES: For a group of patients who underwent reverse PAO, (1) Do patients undergoing reverse PAO demonstrate short-term improvement in pain, function, and hip ROM, and decreased acetabular coverage, as defined by lateral and anterior center-edge angle and Tönnis angle? (2) Are there identifiable factors associated with success or adverse outcomes of reverse PAO as defined by reoperation, conversion to THA, or poor patient-reported outcome scores? (3) Are there identifiable factors associated with early complications? METHODS: Between 2003 and 2017, two surgeons carried out 49 reverse PAOs in 37 patients. Twenty-five patients had unilateral reverse PAO and 12 patients had staged, bilateral reverse PAOs. To ensure that each hip was an independent data point for statistical analysis, we chose to include in our series only the first hip in the patients who had bilateral reverse PAOs. During the study period, our general indications for this operation were symptomatic lateral and anterior acetabular overcoverage causing FAI that had failed to respond to previous conservative or surgical treatment. Thirty-seven hips in 37 patients with a median (range) age of 18 years (12 to 41; interquartile range 16 to 21) were included in this retrospective study at a minimum follow-up of 2 years (median 6 years; range 2 to 17). Thirty-four patients completed questionnaires, 24 patients had radiographic evaluation, and 23 patients received hip ROM clinical examination. However, seven patients had not been seen in more than 5 years. The clinical and radiographic parameters of all 37 hips that underwent reverse PAO in 37 patients from a longitudinally maintained institutional database were retrospectively studied preoperatively and postoperatively. Adverse outcomes were considered conversion to THA or a WOMAC pain score greater than 10 at least 2 years postoperatively. Patient-reported outcomes, radiographic measurements, and hip ROM were evaluated preoperatively and at most recent follow-up using a paired t-test or McNemar test, as appropriate. Linear regression analysis was used to assess for identifiable factors associated with clinical outcomes. Logistic regression analysis was used to assess for identifiable factors associated with adverse outcomes and surgical complications. All tests were two-sided, and p values less than 0.05 were considered significant. RESULTS: At a minimum of 2 years after reverse PAO, patients experienced improvement in WOMAC pain (-7 [95% CI -9 to -5]; p < 0.001), stiffness (-2 [95% CI -3 to -1]; p < 0.001), and function scores (-18 [95% CI -24 to -12]; p < 0.001) and modified Harris Hip Score (mHHS) (20 [95% CI 13 to 27]; p < 0.001). The mean postoperative hip ROM improved in internal rotation (8° [95% CI 2° to 14°]; p = 0.007). Acetabular coverage, as defined by lateral center-edge angle (LCEA), anterior center-edge angle (ACEA), and Tönnis angle, improved by -8° (95% CI -12° to -5°; p < 0.001) for LCEA, -12° (95% CI -15° to -9°; p < 0.001) for ACEA, and 9° (95% CI 6° to 13°; p < 0.001) for Tönnis angle. The postoperative severity of radiographic arthritis was associated with worse WOMAC function scores such that for each postoperative Tönnis grade, WOMAC function score increased by 12 points (95% CI 2 to 22; p = 0.03). A greater postoperative Tönnis grade was also correlated with worse mHHS, with an average decrease of 12 points (95% CI -20 to -4; p = 0.008) in mHHS for each additional Tönnis grade. Presence of a positive postoperative anterior impingement test was associated with a decrease in mHHS score at follow-up, with an average 23-point decrease in mHHS (95% CI -34 to -12; p = 0.001). Nineteen percent (7 of 37) of hips had surgery-related complications. Four hips experienced adverse outcomes at final follow-up, with two patients undergoing subsequent THA and two with a WOMAC pain score greater than 10. We found no factors associated with complications or adverse outcomes. CONCLUSION: The early clinical and radiographic results of true reverse PAO compare favorably to other surgical treatments for pincer FAI, suggesting that reverse PAO is a promising treatment for cases of pincer FAI caused by global acetabular overcoverage. However, it is a technically complex procedure that requires substantial training and preparation by a surgeon who is already familiar with standard PAO, and it must be carefully presented to patients with discussion of the potential risks and benefits. Future studies are needed to further refine the indications and to determine the long-term outcomes of reverse PAO. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Does the Rule of Thirds Adequately Detect Deficient and Excessive Acetabular Coverage?

BACKGROUND: Assessment of AP acetabular coverage is crucial for choosing the right surgery indication and for obtaining a good outcome after hip-preserving surgery. The quantification of anterior and posterior coverage is challenging and requires either other conventional projections, CT, MRI, or special measurement software, which is cumbersome, not widely available and implies additional radiation. We introduce the "rule of thirds" as a promising alternative to provide a more applicable and easy method to detect an excessive or deficient AP coverage. This method attributes the intersection point of the anterior (posterior) wall to thirds of the femoral head radius (diameter), the medial third suggesting deficient and the lateral third excessive coverage. QUESTION/PURPOSE: What is the validity (area under the curve [AUC], sensitivity, specificity, positive/negative likelihood ratios [LR(+)/LR(-)], positive/negative predictive values [PPV, NPV]) for the rule of thirds to detect (1) excessive and (2) deficient anterior and posterior coverages compared with previously established radiographic values of under-/overcoverage using Hip2Norm as the gold standard? METHODS: We retrospectively evaluated all consecutive patients between 2003 and 2015 from our institutional database who were referred to our hospital for hip pain and were potentially eligible for joint-preserving hip surgery. We divided the study group into six specific subgroups based on the respective acetabular pathomorphology to cover the entire range of anterior and posterior femoral coverage (dysplasia, overcoverage, severe overcoverage, excessive acetabular anteversion, acetabular retroversion, total acetabular retroversion). From this patient cohort, 161 hips were randomly selected for analysis. Anterior and posterior coverage was determined with Hip2Norm, a validated computer software program for evaluating acetabular morphology. The anterior and posterior wall indices were measured on standardized AP pelvis radiographs, and the rule of thirds was applied by one observer. RESULTS: The detection of excessive anterior and posterior acetabular wall using the rule of thirds revealed an AUC of 0.945 and 0.933, respectively. Also the detection of a deficient anterior and posterior acetabular wall by applying the rule of thirds revealed an AUC of 0.962 and 0.876, respectively. For both excessive and deficient anterior and posterior acetabular coverage, we found high specificities and PPVs but low sensitivities and NPVs. CONCLUSION: We found a high probability for an excessive (deficient) acetabular wall when this intersection point lies in the lateral (medial) third, which would qualify for surgical correction. On the other hand, if this point is not in the lateral (medial) third, an excessive (deficient) acetabular wall cannot be categorically excluded. Thus, the rule of thirds is very specific but not as sensitive as we had expected. LEVEL OF EVIDENCE: Level II, diagnostic study.

What Mid-term Patient-reported Outcome Measure Scores, Reoperations, and Complications Are Associated with Concurrent Hip Arthroscopy and Periacetabular Osteotomy to Treat Dysplasia with Associated Intraarticular Abnormalities?

BACKGROUND: Periacetabular osteotomy (PAO) is a well-accepted treatment for acetabular dysplasia, but treatment success is not uniform. Concurrent hip arthroscopy has been proposed for select patients to address intraarticular abnormalities. The patient-reported outcomes, complications, and reoperations for concurrent arthroscopy and PAO to treat acetabular dysplasia remain unclear. QUESTIONS/PURPOSES: (1) What are the functional outcome scores among select patients treated with PAO plus concurrent hip arthroscopy at mid-term follow-up? (2) What factors are associated with conversion to THA or persistent symptoms (modified Harris hip score ≤ 70 or WOMAC pain subscore ≥ 10)? (3) What proportion of patients underwent further hip preservation surgery at mid-term follow-up? (4) What are the complications associated with the procedure? METHODS: Between November 2005 and December 2012, 78 patients (81 hips) who presented with symptomatic acetabular dysplasia-defined as a lateral center-edge angle less than 20° with hip pain for more than 3 months that interfered with daily function-had undergone unsuccessful nonsurgical treatment, had associated intraarticular abnormalities on MRI, and underwent combined hip arthroscopy and PAO. Eleven patients did not have minimum 4-year follow-up and were excluded, leaving 67 patients (70 hips) who met our inclusion criteria and had a mean follow-up duration of 6.5 ± 1.6 years. We retrospectively evaluated patient-reported outcomes at final follow-up using the University of California Los Angeles (UCLA) activity score, the modified Harris Hip Score (mHHS), and the WOMAC pain subscore. Conversion to THA or persistent symptoms were considered clinical endpoints. Repeat surgical procedures were drawn from a prospectively maintained database, and major complications were graded according to the validated Clavien-Dindo classification (Grade III or IV). Student t-tests, chi-square tests, and Fisher exact tests identified the association of patient factors, radiographic measures, and surgical details with clinical endpoints. For patients who underwent bilateral procedures, only the first hip was included in our analyses. RESULTS: At final follow-up, the mean mHHS for all patients improved from a mean ± SD of 55 ± 19 points to 85 ± 17 points (p < 0.001), the UCLA activity score improved from 6.5 ± 2.7 points to 7.5 ± 2.2 points (p = 0.01), and the WOMAC pain score improved from 9.1 ± 4.3 points to 3.2 ± 3.9 points (p < 0.001). Three percent (2 of 67) of patients underwent subsequent THA, while 21% (15 of 70) of hips were persistently symptomatic, defined as mHHS less than or equal to 70 or WOMAC pain subscore greater than or equal to 10. Univariate analyses indicated that no patient demographics, preoperative or postoperative radiographic metrics, or intraoperative findings or procedures were associated with subsequent THA or symptomatic hips. Worse baseline mHHS and WOMAC pain scores were associated with subsequent THA or symptomatic hips. Seven percent (5 of 67) of patients underwent repeat hip preservation surgery for recurrent symptoms, and 4% (3 of 67) of patients had major complications (Clavien-Dindo Grade III or IV). CONCLUSION: This study demonstrated that concurrent hip arthroscopy and PAO to treat symptomatic acetabular dysplasia (with intraarticular abnormalities) has good clinical outcomes at mid-term follow-up in many patients; however, persistent symptoms or conversion to THA affected almost a quarter of the sample. We noted an acceptable complication profile. Further study is needed to directly compare this approach to more traditional techniques that do not involve arthroscopy. We do not use isolated hip arthroscopy to treat symptomatic acetabular dysplasia. LEVEL OF EVIDENCE: Level IV, therapeutic study.

High Risk of Conversion to THA After Femoroacetabular Osteoplasty for Femoroacetabular Impingement in Patients Older than 40 Years.

BACKGROUND: Femoroacetabular impingement (FAI) is a recognized cause of hip pain and decreased quality of life and has been linked to primary idiopathic hip osteoarthritis (OA). Although the operative indications for FAI have expanded to include older patients, we do not know whether there is an increased risk of conversion to THA after femoroacetabular osteoplasty (FAO) via the mini-open approach for FAI in patients older than 40 years compared with younger patients, after controlling for other confounding variables. QUESTIONS/PURPOSES: (1) After matching for gender, BMI, preoperative symptomatic period, surgeon experience, Tönnis grade, and degree of chondral lesion, are patients older than 40 years who undergo FAO for FAI more likely to be revised to THA at a minimum of 2 years' follow-up than are patients younger than 40? (2) Is there a difference in delta (postoperative minus preoperative) improvement in functional outcome scores in those patients who did not go on to THA between patients older than and younger than 40 years? METHODS: Between 2003 and 2017, one surgeon performed 281 FAOs via the mini-open approach in patients older than 40 years and 544 of the same procedure in patients younger than 40 years. During that period, the general indications for FAO were the same in both age groups: (1) history and physical exam consistent with FAI, (2) radiographic evidence of focal impingement (cam, pincer, or both), (3) evidence of labral or chondrolabral tears, and (4) minimal to no arthritic changes (all four criteria required). In general, age was not used as a contraindication for surgery. A total of 86% (241 of 281) of patients older than 40 and 91% (494 of 544) of those younger than 40 were available for minimum of 2 years' follow-up, had complete datasets (radiographs as well as preoperative and most recent patient-reported outcomes scores) at a minimum of 2 years after surgery, and were considered eligible for the match. Propensity score matching was used to match for BMI, gender, preoperative symptomatic period, surgeon experience, Tönnis grade, and degree of intraoperative chondral lesion. We matched at a 1:2 ratio 130 patients older than age 40 with 260 patients younger than age 40. The mean ± SD follow-up duration for both groups was 5 ± 2 years. The mean age of the cohort of interest was 47 ± 5 years compared with 28 ± 7 years in the control. Fifty-four percent (70 of 130) of patients older than 40 years were women and 46% (60 of 130) were men; for those younger than 40, 51% (133 of 260) of participants were women and 49% (127 of 260) were men. Tönnis grade distribution for patients older than 40 was as follows: 46% (60 of 130) had Grade 0, 42% (55 of 130) had Grade 1, and 12% (15 of 130) had Grade 2. In comparison, Tönnis grade for patients younger than 40 was as follows: 52% (136 of 260) had Grade 0, 38% (100 of 260) had Grade 1, and 9% (24 of 260) had Grade 2 (p = 0.49). Chondral lesion degree was determined intraoperatively as none, a partial-thickness tear, or a full-thickness tear. Tönnis grade was determined based on preoperative plain AP hip radiographs. We then compared the percentage of patients who converted to THA during the surveillance period (our primary study outcome). We also compared the difference in delta (preoperative minus postoperative) improvement in functional outcome scores using the modified Harris Hip Score (mHHS) between the groups, excluding those who had already been converted to THA. RESULTS: In patients older than 40 years, 16% (21 of 130) converted to THA at a mean time to conversion of 2 ± 1 years compared with 7% (17 of 260) at a mean time of 2 ± 2 years in patients younger than 40 years (p = 0.01). At a mean of 5 ± 2 years after FAO, among those patients who had not undergone conversion to THA, the mean delta mHHS score for patients older than 40 was 11 ± 17, compared with 20 ± 26 for patients younger than 40 (p = 0.04). CONCLUSION: Since approximately 1 in 6 patients older than 40 years in this series who underwent FAO for FAI opted for early conversion to THA at a mean time of 2 years after the osteoplasty procedure, and the remaining patients who did not undergo THA reported lower improvement in functional outcomes, we recommend surgeons avoid this procedure in patients in this age group until or unless we can better refine our indications. This is especially true because loss to follow-up causes us to believe that, if anything, our estimates of the risk of conversion to THA are conservative. LEVEL OF EVIDENCE: Level III, therapeutic study.

ARCO Consensus on the Pathogenesis of Non-traumatic Osteonecrosis of the Femoral Head.

Osteonecrosis of the femoral head (ONFH) is a devastating disease frequently leading to femoral head collapse and hip arthritis. Specifically, non-traumatic ONFH primarily affects young and middle-aged adults. Although compromised local circulation of the femoral head seems to be pathognomonic for the disease, the pathogenesis is perplexing and continues to be an area of scrutiny and research. Comprehension of the pathogenesis is of crucial importance for developing and guiding treatments for the disease. Therefore, we provide an up-to-date consensus on the pathogenesis of non-traumatic ONFH.

Identification of potential miRNA biomarkers for traumatic osteonecrosis of femoral head.

Traumatic osteonecrosis of femoral head (TONFH) is a common orthopedic disease caused by physical injury in hip. However, the unclear pathogenesis mechanism of TONFH and lacking of simple noninvasive early diagnosis method cause the necessity of hip replacement for most patients with TONFH. In this study, we aimed to identify circulating microRNAs (miRNAs) by integrated bioinformatics analyses as potential biomarker of TONFH. mRNA expression profiles were downloaded from the Gene Expression Omnibus database. Then we combined two miRNA screen methods: Weighted gene co-expression network analysis and fold change based differentially expressed miRNAs analysis. As a result, we identified 14 key miRNAs as potential biomarkers for TONFH. Besides, 302 target genes of these miRNAs were obtained and the miRNA-mRNA interaction network was constructed. Furthermore, the results of Kyoto Encyclopedia of Gene and Genome pathway analysis, Gene Ontology function analysis, protein-protein interaction (PPI) network analysis and PPI network module analysis showed close correlation between these 14 key miRNAs and TONFH. Then we established receiver operating characteristic curves and identified 6-miRNA signature with highly diagnosis value including miR-93-5p (area under the curve [AUC] = 0.93), miR-1324 (AUC = 0.92), miR-4666a-3p (AUC = 0.92), miR-5011-3p (AUC = 0.92), and miR-320a (AUC = 0.89), miR-185-5p (AUC = 0.89). Finally, the results of quantitative real-time polymerase chain reaction confirmed the significantly higher expression of miR-93-5p and miR-320a in the serum of patients with ONFH. These circulating miRNAs could serve as candidate early diagnosis markers and potential treatment targets of TONFH.

Bone Mineral Density in Patients Suffering from Ménière's Disease.

INTRODUCTION: Previous studies have reported an association between reduced bone mineral density and the occurrence of benign paroxysmal positional vertigo, balance impairment, and saccular dysfunction. Furthermore, the results of recent animal studies have raised the possibility that vestibular dysfunction could affect bone remodeling and bone mass. The goal of the study was to compare bone mineral density of patients suffering from definite Ménière's disease to that of a matched control group. METHODS: We conducted a case-control cross-sectional study in a tertiary referral center. The study group included 23 patients suffering from definite Ménière's disease, and the control group was comprised of 23 patients matched in their race, gender, and age parameters in whom no vestibular pathology could be found. Dual energy X-ray absorptiometry of the femoral head was used for the assessment of bone mineral density. The T and Z scores of the femoral heads' bone mineral density were compared. RESULTS: The average T scores were -1.53 ± 1.08 in the study and -0.39 ± 0.72 (p = 0.016) in the control groups, and the Z scores were -0.4 ± 0.63 and 0.33 ± 0.31 (p = 0.018), respectively. Seventeen patients (74%) of the study group and 9 (39%) of the control group had T scores less than -1.0, indicating osteopenia/osteoporosis (p = 0.036). CONCLUSIONS: The results showed a significant association between Ménière's disease and reduced bone mineral density of the femoral head. Bone mineral density studies of the weight-bearing bones are warranted in Ménière's disease for the early diagnosis and treatment of osteopenia/osteoporosis on the one hand and possible benefit of this treatment for the evolution of Ménière's disease on the other hand.

Effect of a Specific Questionnaire Sheet on Subclassification of Osteonecrosis of the Femoral Head.

BACKGROUND This study examined whether use of a specific questionnaire sheet for nontraumatic osteonecrosis of the femoral head (ONFH) could affect the subclassification of ONFH compared with a conventional medical interview. MATERIAL AND METHODS Study participants consisted of 400 patients with ONFH who visited our hospital between February 2011 and March 2015. Data on history of systemic steroid therapy and habitual alcohol intake were obtained during a conventional medical interview at the first visit and were re-evaluated using a specific questionnaire sheet at another visit. Patients were subclassified into 4 groups: steroid-associated, alcohol-associated, steroid/alcohol-associated, or idiopathic ONFH. RESULTS Use of the specific questionnaire sheet resulted in a 4.0% increase in the proportion of patients with a history of systemic steroid therapy, from 57.3% (n=229) to 61.3% (n=245), and a 14.3% increase for history of habitual alcohol intake, from 35.0% (n=140) to 49.3% (n=197). The proportion of patients with steroid/alcohol-associated ONFH increased from 2.5% (n=10) to 17.8% (n=71), while the proportion in the other 3 groups decreased: steroid-associated ONFH from 54.8% (n=219) to 43.5% (n=174); alcohol-associated ONFH from 32.5% (n=130) to 31.5% (n=126); and idiopathic ONFH from 10.2% (n=41) to 7.2% (n=29). Ninety-six patients (24.0%) were classified into a different subgroup based on the specific questionnaire sheet. CONCLUSIONS The use of a specific questionnaire sheet can change the distribution of ONFH subclassifications compared with use of a conventional medical history interview. Use of a specific questionnaire sheet can allow for more detailed self-reporting regarding potential causative factors for nontraumatic ONFH, especially habitual alcohol intake.

The effect of the necrotic area on the biomechanics of the femoral head - a finite element study.

BACKGROUND: Femoral head collapse is the key to the progress of osteonecrosis of the femoral head (ONFH), but the causes of collapse are not completely clear. The better understanding of the progress of femoral head collapse will guide the treatment strategy for ONFH patients. The purpose of this study was to evaluate the biomechanical influence of necrosis area on the collapse of the femoral head by finite element analysis. METHODS: CT and MRI data from the hip joint of a healthy volunteer were collected to establish a finite element (FE) model of a normal hip. Subsequently, five categories of osteonecrosis FE models were established by using the normal model and computer software according to China-Japan Friendship Hospital (CJFH) classification for ONFH. The CJFH system includes five types based on the size and location of necrosis lesions in the femoral head (type M, C, L1, L2, and L3) and the stage of ONFH. The collapse indices of each model were analyzed by FE method, including the displacement, peak von Mises stress and stress index of the simulated necrotic area as well as the lateral pillar contact area of the femoral head to acetabular. RESULTS: (1) The displacement increments in the simulated necrotic areas of type M, C, L1, L2, and L3 models were 3.75 µm, 8.24 µm, 8.47 µm, 18.42 µm, and 20.44 µm respectively; the peak von Mises stress decrements were 1.50 MPa, 3.74 MPa, 3.73 MPa, 4.91 MPa, and 4.92 MPa respectively; and the stress indices were 0.04, 0.08, 0.08, 0.27, and 0.27 respectively. (2) The displacement increments in the lateral pillar contact areas of five type models were significantly different (P < 0.001) and increased in sequence as follows: 1.93 ± 0.15 µm, 5.74 ± 0.92 µm, 5.84 ± 1.42 µm, 14.50 ± 3.00 µm, and 16.43 ± 3.05 µm. The peak von Mises stress decrements were also significantly different (P < 0.001) and increased in sequence as follows: 0.52 ± 0.30 MPa, 0.55 ± 0.12 MPa, 0.67 ± 0.33 MPa, 4.17 ± 0.59 MPa, and 4.19 ± 0.60 MPa. (3) The collapse indices including the displacement increments and peak von Mises stress decrements of type L2 and L3 models were markedly higher than those of type M, C, and L1 models (P < 0.001). CONCLUSIONS: The collapse indices of the femoral heads of type L2 and L3 FE models were significantly higher than those of type M, C, and L1. Different areas of necrosis result in varied impact on the femoral head collapse.

Does Early Proximal Femoral Varus Osteotomy Shorten the Duration of Fragmentation in Perthes Disease? Lessons From a Prospective Multicenter Cohort.

BACKGROUND: The prognosis of Legg-Calvé-Perthes disease (LCPD) is dependent upon several factors, with the length and severity of the fragmentation stage among the most important. Previous retrospectively collected data from a single center have suggested that early proximal femoral varus osteotomy (PFO) may shorten the length of fragmentation and allow 34% of patients to bypass fragmentation altogether resulting in less femoral head deformity. The purpose of this study was to validate these findings in a prospectively collected multicenter cohort. METHODS: Patients with LCPD treated with early PFO (during Waldenström stage I) were prospectively followed with serial radiographs at 3-month intervals until a minimum of 2-year follow-up. Waldenström stages and lateral pillar class were determined by mode assessments from 3 pediatric orthopaedic surgeons. The duration of fragmentation was defined as the interval between the first radiographs demonstrating features of stage IIa and stage IIIa. "Complete" bypass was defined as the absence of stage IIa or IIb findings on sequential radiographs with no development of femoral head deformity or collapse. "Partial" bypass was defined as the absence of advanced features of fragmentation and femoral head collapse (stage IIb). RESULTS: Forty-six patients (80% male individuals) with initial stage LCPD and a mean age of 8.2±1.2 years were identified. The weighted kappa statistics for Waldenström staging and lateral pillar classifications showed excellent (0.833) and substantial (0.707) agreement, respectively. Ninety-eight percent of patients (45/46) underwent some period of fragmentation lasting between 91 and 518 days; the median duration was 206 days (interquartile range, 181 to 280). One patient (2%) bypassed fragmentation completely; 8 patients (17%) demonstrated partial bypass. Patients who completely or partially bypassed fragmentation experienced significantly less severe lateral pillar collapse (P=0.016) and shorter fragmentation duration (P=0.001). CONCLUSIONS: In this prospective multicenter cohort, we found a lower rate of fragmentation bypass than previously reported. Nonetheless, our data support the previous contention that early PFO may shorten fragmentation and minimize collapse in LCPD compared with historical controls. Further study with larger cohorts and a more rigorous definition of what constitutes bypass is warranted to clarify the effect of early PFO on the reparative biology of LCPD. LEVEL OF EVIDENCE: Level IV-therapeutic study.

How do global sagittal alignment and posture change after total hip arthroplasty?

BACKGROUND: Postural change after total hip arthroplasty (THA) is still a matter of discussion. Previous studies have mainly concentrated on the pelvic motions. We report the post-operative changes of the global sagittal posture using pelvic, spinal, and lower extremities parameters. METHODS: 139 patients (primary THA, without previous spinal or lower extremity surgery) were included. We measured pelvic parameters [SS, sacral slope; PI, pelvic incidence; PT, pelvic tilt; APP angle, anterior pelvic plane angle] and the global posture parameters (SVA, sagittal vertical angle; GSA, global sagittal angle; TPA, T1 pelvic angle). Patients were categorized into low PI group < 45°, 45° < medium PI < 65°, and high PI > 65°. RESULTS: Mean GSA and SVA decreased post-operatively (p = 0.005 and p = 0.004 respectively). The TPA change was not significant (p = 0.078). In the low PI group, GSA (5.4 ± 5.0 to 4.3 ± 4.0, p = 0.005) and SVA (5.4 ± 4.9 to 4.2 ± 4.1, p = 0.038) decreased with more posterior pelvic tilt. Post-operative TPA was significantly higher (8.4 ± 10.6 to 9.8 ± 10.7; p = 0.048). In the medium PI group, SVA decreased (4.2 ± 4.6 to 3.6 ± 4.5, p = 0.020) with more posterior pelvic tilt. In the high PI group, pelvic and global posture parameters did not evolve significantly. CONCLUSION: PI is the key determining factor in pelvic tilt modification after THA. Patients with low PI demonstrate significant modification in spine, pelvic, and lower extremities. Pelvic tilt is the main adaptation mechanism for medium incidence patients whereas pelvic tilt does not change in high PI patients after surgery.

Cartilage Homeostasis Affects Femoral Head Necrosis Induced by Methylprednisolone in Broilers.

(1) Background: Since the large-scale poultry industry has been established, femoral head necrosis (FHN) has always been a major leg disease in fast-growing broilers worldwide. Previous research suggested that cartilage homeostasis could be taken into consideration in the cause of FHN, but the evidence is insufficient. (2) Methods: One-day-old broiler chickens were randomly divided into three groups, 16 broilers per group. The birds in group L were injected intramuscularly with methylprednisolone (MP) twice a week for four weeks (12.5 mg·kg-1). The birds in group H were injected intramuscularly with MP (20 mg·kg-1·d-1) for 7 d (impulse treatment). The birds in group C were treated with sterile saline as a control group. Broilers were sacrificed at 42 and 56 d. Blood samples were collected from the jugular vein for ELISA and biochemical analysis. Bone samples, including femur, tibia, and humerus, were collected for histopathological analysis, bone parameters detection, and real-time quantitative PCR detection. (3) Results: The FHN broilers in group L and H both showed lower body weight (BW) and reduced bone parameters. In addition, the MP treatment resulted in reduced extracellular matrix (ECM) anabolism and enhanced ECM catabolism. Meanwhile, the autophagy and apoptosis of chondrocytes were enhanced, which led to the destruction of cartilage homeostasis. Moreover, the impulse MP injection increased the portion of birds with severer FHN, whereas the MP injection over a long period caused a more evident change in serum cytokine concentrations and bone metabolism indicators. (4) Conclusions: The imbalance of cartilage homeostasis may play a critical role in the development of FHN in broilers. FHN broilers induced by MP showed a more pronounced production of catabolic factors and suppressed the anabolic factors, which might activate the genes of the WNT signal pathway and hypoxia-inducible factors (HIFs), and then upregulate the transcription expression of ECM to restore homeostasis.

Acetabular retroversion in dysplastic hips is associated with decreased 3D femoral head coverage independently from lateral center-edge angle.

INTRODUCTION: The clinical significance of acetabular retroversion in non-dysplastic hips can be explained as pincer-type femoroacetabular impingement (FAI), whereas that in dysplastic hips is not clarified because FAI normally poses little problems for dysplastic hips. We aimed to evaluate three-dimensional (3D) femoral head coverage in dysplastic hips with and without acetabular retroversion and to elucidate the role of acetabular retroversion on the 3D femoral head coverage. MATERIALS AND METHODS: We retrospectively investigated 93 hips in 93 patients (9 males and 84 females) that underwent periacetabular osteotomy for hip dysplasia. Dysplastic hips were divided into anteversion and retroversion groups according to their cranial anteversion, which was measured on the axial section 5 mm caudal to the acetabular roof. The 3D femoral head coverage was provided as a percentage of the acetabulum-covered surface area of the upper femoral hemisphere using a 3D preoperative planning software for total hip arthroplasty. RESULTS: Of the 93 dysplastic hips, 15 hips (16%) were assigned to the retroversion group, which had significantly younger age at surgery (31.9 years versus 39.2 years; p = 0.033). The lateral center-edge angles were comparable between the groups (13.8° versus 12.9°; p = 0.68); however, the hips in the retroversion group had a trend of smaller 3D femoral head coverage than those in the anteversion group (59% versus 63%; p = 0.058). Multivariate analysis using two-way analysis of covariance showed that lateral center-edge angle (partial regression coefficient = 0.83; t value = 17.3; p < 0.001) and acetabular retroversion (partial regression coefficient = - 2.3; t value = - 4.9; p < 0.001) were independent factors that contributed to the 3D femoral head coverage. CONCLUSIONS: Acetabular retroversion in dysplastic hips was associated with decreased 3D femoral head coverage independently from lateral center-edge angle. The age at surgery in the retroversion group was significantly younger, suggesting a relationship between decreased 3D coverage and potentially earlier symptom onset.

The influence of ageing on the incidence and site of trauma femoral fractures: a cross-sectional analysis.

BACKGROUND: This study aimed to determine the influence of ageing on the incidence and site of femoral fractures in trauma patients, by taking the sex, body weight, and trauma mechanisms into account. METHODS: This retrospective study reviewed data from adult trauma patients aged ≥20 years who were admitted into a Level I trauma center, between January 1, 2009 and December 31, 2016. According to the femoral fracture locations, 3859 adult patients with 4011 fracture sites were grouped into five subgroups: proximal type A (n = 1359), proximal type B (n = 1487), proximal type C (n = 59), femoral shaft (n = 640), and distal femur (n = 466) groups. A multivariate logistic regression analysis was applied to identify independent effects of the univariate predictive variables on the occurrence of fracture at a specific site. A two-dimensional plot was presented visually with age and the propensity score accounts for the risk of a fracture at a specific femoral site. RESULTS: This analysis revealed that older age was an independent variable that could positively predict the occurrence of proximal type A (OR [95%CI]: 1.03 [1.03-1.04], p < 0.001) and B fractures (1.02 [1.01-1.02], p < 0.001), and negatively predict the occurrence of proximal type C (0.96 [0.94-0.98], p < 0.001), shaft (0.95 [0.95-0.96], p < 0.001), and distal fractures (0.98 [0.98-0.99], p < 0.001). DISCUSSION: Using the propensity scores which account for the risk of a fracture in a specific femoral site, this study revealed that the older patients were at a higher risk of developing proximal type A and type B fractures, while a lower risk of developing fractures in the shaft and distal femur. This incidence of fracture site can largely be explained by age-related factors, including a decrease in bone strength and falling being the most common mechanism of trauma in older patients. CONCLUSIONS: This study revealed a difference in the involvement of age in the incidence of femoral fracture sites in the trauma patients.

Three-dimensional finite element analysis of silk protein rod implantation after core decompression for osteonecrosis of the femoral head.

BACKGROUND: Several methods are available for the treatment of early-stage osteonecrosis of the femoral head. Core decompression with implantation is a widely-used treatment. However, no single implant is recognized as the most effective way to prevent disease progression. Silk has high strength and resiliency. This study explored the possibility of a strong and resilient silk protein biomaterial as a new alternative implant. METHODS: We investigated the biomechanical properties of the silk protein material by regular compression, torsion, and three-point bending tests. We established three-dimensional finite element models of different degrees of femoral head osteonecrosis following simple core decompression, fibula implantation, porous tantalum rod implantation, and silk protein rod implantation. Finally, we compared the differences in displacement and surface stress under load at the femoral head weight-bearing areas between these models. RESULTS: The elastic modulus and shear modulus of the silk protein material was 0.49GPa and 0.66GPa, respectively. Three-dimensional finite element analyses demonstrated less displacement and surface stress at the femoral head weight-bearing areas following silk protein rod implantation compared to simple core decompression (p < 0.05), regardless of the extent of osteonecrosis. No differences were noted in the surface deformation or surface stress of the femoral head weight-bearing areas following silk protein rod, fibula or tantalum rod implantation (p > 0.05). CONCLUSIONS: When compared with simple core decompression, silk protein rod implantation demonstrated less displacement and surface stress at the femoral head weight-bearing area, but more than fibula or tantalum rod implantation. Similar effects on the surface stress of the femoral head between the silk rod, fibula and tantalum rod implantations, combined with additional modifiable properties support the use of silk protein as a suitable biomaterial in osteonecrosis surgery.

Capital Femoral Epiphyseal Extension May Confer Physeal Stability in Slipped Capital Femoral Epiphysis.

BACKGROUND: Factors including obesity and morphologic parameters around the hip that increase physeal stress are associated with an increased risk of slipped capital femoral epiphysis (SCFE). Recent evidence suggests that superior epiphyseal extension may confer stability to the physis and help protect against SCFE. The purpose of this study is to investigate the relationship between epiphyseal extension and SCFE using an age-matched and sex-matched cohort study. METHODS: We generated 2 separate cohorts for comparison: 89 patients with unilateral SCFE and 89 healthy subjects with no evidence of hip disease or deformity. We utilized the anterior-posterior and lateral films of the hip to measure the Southwick angle and the epiphyseal extension ratio (EER), defined as the ratio of extension of the capital femoral epiphysis down the femoral neck relative to the diameter of the femoral head. We then compared these measurements between cohorts and in subgroup analysis based on slip stability and whether subjects progressed to a contralateral slip. RESULTS: The SCFE cohort demonstrated a decreased superior epiphyseal extension ratio compared with control (superior EER 0.71 vs. 0.68, P=0.002). There was also a significant downward trend in superior EER from the control subjects (0.71±0.07) to the stable slips (0.69±0.06) to the unstable slips (0.65±0.04) with an overall difference between the groups (P=0.001). Eighteen of 44 (41%) subjects with unilateral stable slips and at least 6 months of follow-up went on to develop SCFE of the contralateral limb. The subjects who developed contralateral slips were younger (11.6±1.2 vs. 12.7±1.4 y, P=0.008); however, there was no difference in superior or anterior epiphyseal extension (P=0.75 and 0.23, respectively). There was no significant linear correlation between Southwick angle and superior or anterior EER (r=0.13 and 0.17, respectively, P>0.05 for both). CONCLUSIONS: Increasing capital femoral epiphyseal extension may confer physeal stability in the setting of SCFE. We propose that this epiphyseal extension reflects an adaptive response to limit physeal stress and reduce the risk for progression to SCFE. LEVEL OF EVIDENCE: Level III-prognostic study.

The Effect Of Increasing Femoral Head Size On The Force Required For Dislocation.

Alternative bearings allow for the increased utilization of large femoral heads in total hip arthroplasty. This study demonstrated the effect of increasing femoral head size on the force required for dislocation during intraoperative assessment. Using a standard posterior approach, 10 cadaver hips underwent total hip arthroplasty; components were implanted in a standard fashion. The extremity was attached to a custom jig to replicate intraoperative assessment (internal rotation with 90° of hip flexion/neutral adduction). This range of motion (ROM) was repeated in triplicate using femoral head sizes of 28mm, 32mm, 36mm, 40mm, and 44mm. The ROM to dislocation (degrees) and torque (N*m) required were recorded. With increasing head sizes, there was a significant increase in torque required for dislocation (p<0.0001). The least square means torques (N*m) for each femoral head size (28-44mm) were 2.07, 2.15, 2.42, 2.74, and 3.65N*m. The corresponding least square means ROMs prior to dislocation were 43.5°, 46.2°, 50.8°, 54.3°, and 59.5°. There was a significant difference in ROM between nonadjacent head sizes (i.e., 28mm and 44mm) (p<0.0001). Total hip implant stability is multifactorial. Increasing femoral head size may confer stability during intraoperative assessment by increasing both the ROM prior to dislocation and the force required for dislocation.

Similar femoral growth and deformity with one screw versus two smooth pins for slipped capital femoral epiphysis.

PURPOSE: To compare longitudinal growth and cam deformity of the proximal femur after treatment for slipped capital femoral epiphysis (SCFE) with one screw versus two smooth pins. METHODS: We studied 43 patients (29 males, 14 females; mean age, 12.1 years; range, 9.5-14 years) with idiopathic unilateral SCFE treated with in situ fixation with one cannulated screw (group A, n = 23) or two smooth pins (group B, n = 20). Anteroposterior and frog-leg radiographs of the pelvis were evaluated for each patient at initial presentation, post-operatively and at physeal closure. Longitudinal growth was evaluated using the femoral neck length (FNL), the caput-collum-diaphyseal (CCD) angle, and the articulo-trochanteric distance (ATD). Cam deformity was assessed using the anterior offset α-angle and the head-neck offset ratio (HNOR). The mean follow-up was 5.1 years (range, 4-7 years). RESULTS: Postoperatively, the mean CCD angle was 138.3°, the mean α-angle was 66.1° and the mean HNOR was - 0.030. At physeal closure, mean CCD angle significantly decreased to 133.6°, mean α-angle significantly reduced to 52.1°, and mean HNOR significantly improved to + 0.039. CCD, FNL, ATD, α-angle, and HNOR were not different between groups. CONCLUSIONS: One screw or two smooth pins result in similar longitudinal growth and deformity of the proximal femur after SCFE. The femoral head-neck junction remarkably improves until physeal closure; however, residual cam deformity is not avoided after in situ pinning. The complication rate with smooth pins is higher.