Risk analysis of patients with an osteolytic acetabular defect after total hip arthroplasty using subject-specific finite-element modelling.

AIMS: Osteolysis, secondary to local and systemic physiological effects, is a major challenge in total hip arthroplasty (THA). While osteolytic defects are commonly observed in long-term follow-up, how such lesions alter the distribution of stress is unclear. The aim of this study was to quantitatively describe the biomechanical implication of such lesions by performing subject-specific finite-element (FE) analysis on patients with osteolysis after THA. PATIENTS AND METHODS: A total of 22 hemipelvis FE models were constructed in order to assess the transfer of load in 11 patients with osteolysis around the acetabular component of a THA during slow walking and a fall onto the side. There were nine men and two women. Their mean age was 69 years (55 to 81) at final follow-up. Changes in peak stress values and loads to fracture in the presence of the osteolytic defects were measured. RESULTS: The von Mises stresses were increased in models of those with and those without defects for both loading scenarios. Although some regions showed increases in stress values of up to 100%, there was only a moderate 11.2% increase in von Mises stress in the series as a whole. The site of fracture changed in some models with lowering of the load to fracture by 500 N. The most common site of fracture was the pubic ramus. This was more frequent in models with larger defects. CONCLUSION: We conclude that cancellous defects cause increases in stress within cortical structures. However, these are likely to lead to a modest decrease in the load to fracture if the defect is large (> 20cm3) or if the patient is small with thin cortical structures and low bone mineral density. Cite this article: Bone Joint J 2018;100-B:1455-62.

Three-dimensional (3D) Printing Technology Assisted by Minimally Invasive Surgery for Pubic Rami Fractures.

The feasibility of three-dimensional (3D) printing technology combined with minimally invasive surgery in the treatment of pubic rami fractures was explored. From August 2015 to October 2017, a series of 30 patients who underwent surgical stabilization of their anterior pelvic ring (all utilizing the 3D printing technology) by one surgeon at a single hospital were studied. The minimally invasive incisions were made through anterior inferior cilia spine and pubic nodule. Data collected included the operative duration, the blood loss, the damage of the important tissue, the biographic union and the recovery of the function after the operation. Measurements on inlet and outlet pelvic cardiograph were made immediately post-operation and at all follow-up clinic visits. The scores of reduction and function were measured during follow-up. Results showed that the wounds of 30 patients were healed in the first stage, and there was no injury of important structures such as blood vessels and nerves. According to the Matta criteria, excellent effectiveness was obtained in 22 cases and good in 8 cases. According to the functional evaluation criteria of Majeed, excellent effectiveness was obtained in 21 cases and good in 9 cases. It was suggested that the 3D printing technology assisted by minimally invasive surgery can better evaluate the pelvic fracture before operation, which was helpful in plate modeling, and can shorten surgery duration and reduce intraoperative blood loss and complications. The positioning accuracy was improved, and better surgical result was finally achieved.

The patellar pubic percussion test: a simple bedside tool for suspected occult hip fractures.

PURPOSE: Patellar finger tapping produces a typical sound that can be detected by a stethoscope positioned on the pubic bone (patellar pubic percussion test (PPPT)). Characteristics of this sound are determined by continuity of bone between patella and pelvis. We hypothesized that a PPPT was able to detect overt hip fractures and occult hip fractures that may not be determined by a standard radiological examination. METHODS: Two independent observers performed a PPPT in patients with a suspected hip or pelvic fracture, just before a conventional radiograph (X-ray) was performed. The PPPT test was scored as negative (similar to contralateral side) or positive (different). Patients with a positive PPPT but with a negative X-ray underwent an additional CT scan. RESULTS: One hundred and ninety-one patients with suspected hip or pelvic fracture were included. A total of 161 patients (84%) were diagnosed with a fracture (hip, n = 142; pelvic, n = 19). An 85% sensitivity, a 70% specificity, a 0.94 positive predictive value, and a 0.47 negative predictive value of the PTTT were calculated. The inter-observer reliability (kappa) was 0.7. Eleven CT scans as indicated by a mismatch between PPPT (positive) and X-ray (no fracture) identified eight fractures (73%). A multivariate analysis demonstrated that a painful passive movement and the PPPT predicted a hip fracture. CONCLUSION: The PPPT is a simple bedside diagnostic tool that is sensitive in detecting clinically straight forward hip fractures as well as occult hip fractures. The PPPT can support decision-making for additional radiological examinations in case of potential occult pelvis or hip fractures.

The puborectal continence reflex: a new regulatory mechanism controlling fecal continence.

PURPOSE: Fecal continence is maintained by voluntary and involuntary contraction of the anal sphincter, and voluntary contractions of puborectal muscle. We investigated whether the puborectal muscle can control fecal continence not only by voluntary contractions but also by involuntary contractions. METHODS: We performed anorectal function tests in 23 healthy subjects. The anorectal pressure test was used to investigate voluntary contractions of the puborectal muscle. The balloon retention test was used to assess if the puborectal muscle can contract involuntarily. RESULTS: During the balloon retention test, we observed an involuntary contraction of the puborectal muscle, which gradually increased during progressive filling of the rectum. The maximal involuntary contraction of the puborectal muscle was significantly stronger and longer than its maximal voluntary contraction (150 versus 70 mmHg, P < 0.001 and 5.8 versus 1.5 min, P < 0.001). CONCLUSIONS: We found that the puborectal muscle is able to contract involuntarily during rectal dilatation. It is a new regulatory mechanism, called the puborectal continence reflex, which controls fecal continence by involuntary contraction of the puborectal muscle. It seems to be initiated by dilatation at the level of the puborectal muscle. Presumably, the puborectal continence reflex protects many patients with anal sphincter dysfunctions from fecal incontinence.

Pelvic musculoskeletal dysfunctions in women with and without chronic pelvic pain.

AIM: This study aimed to compare the prevalence of pelvic musculoskeletal dysfunctions in women with and without Chronic Pelvic Pain (CPP). MATERIALS &METHODS: A total of 84 women with and without CPP (42 in each group), participated in this cross-sectional analytical study. After collecting demographic information, clinical examinations were carried out to compare pelvic musculoskeletal dysfunctions between two groups. Kolmogorov-Smirnov (K-S) goodness-of-fit, Independent t, X2 and Pearson correlation tests were used for data analysis. Values of p < 0.05 were considered statistically significant. FINDINGS: Significant differences were found in the asymmetric iliac crest and pubic symphysis height (45.2% vs 9.5%), positive sacroiliac provocation and positive Carnett's tests (50% vs 4.8%), (p < 0.05). CPP Patients exhibited more tenderness at Levator ani, Piriformis, and Obturator Internus muscles, also higher degrees of pelvic inclination (p < 0.05). CONCLUSION: Higher frequency of pelvic musculoskeletal dysfunctions in women with CPP suggests the value of routine musculoskeletal examinations for earlier diagnosis of musculoskeletal originated CPP and effective management of these patients.

The prevalence and risk factors for delayed union of the superior pubic ramus at one year after curved periacetabular osteotomy: its risk factor and outcome.

PURPOSE: Curved periacetabular osteotomy (CPO) has been developed for the treatment of acetabular dysplasia. While several studies have reported its good clinical results, the complications of CPO include delayed union and nonunion of the superior pubic ramus. The purpose of this study is to investigate the prevalence of delayed union of the pubis one year after CPO, and to determine the risk factors for this complication. METHODS: The study examined 113 hips that underwent CPO between 2008 and 2012. Delayed union was assessed based on the anteroposterior radiography one year after CPO. A superior pubic ramus union group (U group) and a delayed union group (D group) were retrospectively compared regarding patient characteristics, clinical evaluations, and radiographic parameters. RESULTS: Delayed union rate was 16.8%. The D group contained a significantly greater proportion of smokers (p < 0.001). The gap at the pubic osteotomy site on CT coronal images was significantly larger in the D group (p < 0.001), and the cut-off value for the risk of nonunion was larger than 5.1 mm. Multivariate regression analysis indicated that smoking (OR 10.7, 95% CI 2.1-55.4) and a gap at the superior pubic ramus >5.1 mm (OR 16.5, 95% CI 3.7-73.7) were significantly associated with delayed union as independent risk factors. CONCLUSION: The prevalence of delayed union one year after CPO was 16.8%. Smoking and a gap larger than 5.1 mm at the pubic osteotomy site are risk factors for delayed union after CPO.

Incidence of delayed union one year after peri-acetabular osteotomy based on computed tomography.

BACKGROUND: Pubic bone nonunion and delayed union are reported as post-operative complications after peri-acetabular osteotomy (PAO). However, few studies have determined the incidence of delayed union using computed tomography (CT) scans. This study aimed to determine the incidence of delayed union at one year after PAO using X-ray and CT scans. METHODS: We performed a retrospective review of 150 hips in 132 consecutive patients with acetabular dysplasia who underwent PAO between January 2012 and June 2016 and evaluated 107 hips for which pelvic CT scans taken at one year after PAO were available. Clinical evaluations included age at surgery, weight, body mass index (BMI) and history. Radiographic evaluations were to assess pubic, ischial and iliac delayed union at one year post-operatively. RESULTS: Based on X-ray analysis, the incidence of delayed union in the pubic, ischial and iliac bones was 11.2% (12 hips), 5.6% (6 hips) and 0% (0 hips), respectively, and20.6% (22 hips), 8.4% (9 hips) and 0% (0 hips), respectively, based on CT scans. CONCLUSION: The incidence of delayed union of the pubis and ischium at one year after PAO according to CT scans was higher than that based on X-ray imaging. CT scans are useful in patients with some symptoms at the osteotomy site. LEVEL OF EVIDENCE: Level III.

van Neck-Odelberg Disease: A 3.5-Year Follow-Up Case Report and Systematic Review.

V an Neck-Odelberg disease (VND) is a benign skeletal overgrowth of the ischiopubic synchondrosis (IPS) in prepubescent patients. There is a paucity of long-term follow-up data and reviews on management decision-making. We report on a 15-year-old female, with a history of sickle-cell disease (HbSS), presenting with unilateral groin pain. Patient's physical examination, radiographs, and a literature-review determined a diagnosis of VND. Conservative treatment was issued. Clinical symptoms resolved at three months, followed by complete lesion resolution at three years. Additionally, a search of Medline (PubMed), EMBASE, and OVID databases was performed. Reports including VND/IPS diagnosis, treatment, or follow-up decisions were identified. Systematic-review found 17 relevant articles, reporting on 29 patients. Patients presented with groin (51.7%) or buttock (20.7%) pain, and were diagnosed using X-ray (n=23) and magnetic resonance imaging (MRI) (n=17). Twenty-five patients were treated conservatively, with two (8.0%) reports of surgical intervention. Average follow-up was 6.25 months. Our case report and systematic-review support conservative treatment for VND.

Cement Augmentation in Sacroiliac Screw Fixation Offers Modest Biomechanical Advantages in a Cadaver Model.

BACKGROUND: Sacroiliac screw fixation in elderly patients with pelvic fractures is prone to failure owing to impaired bone quality. Cement augmentation has been proposed as a possible solution, because in other anatomic areas this has been shown to reduce screw loosening. However, to our knowledge, this has not been evaluated for sacroiliac screws. QUESTIONS/PURPOSES: We investigated the potential biomechanical benefit of cement augmentation of sacroiliac screw fixation in a cadaver model of osteoporotic bone, specifically with respect to screw loosening, construct survival, and fracture-site motion. METHODS: Standardized complete sacral ala fractures with intact posterior ligaments in combination with ipsilateral upper and lower pubic rami fractures were created in osteoporotic cadaver pelves and stabilized by three fixation techniques: sacroiliac (n = 5) with sacroiliac screws in S1 and S2, cemented (n = 5) with addition of cement augmentation, and transsacral (n = 5) with a single transsacral screw in S1. A cyclic loading protocol was applied with torque (1.5 Nm) and increasing axial force (250-750 N). Screw loosening, construct survival, and sacral fracture-site motion were measured by optoelectric motion tracking. A sample-size calculation revealed five samples per group to be required to achieve a power of 0.80 to detect 50% reduction in screw loosening. RESULTS: Screw motion in relation to the sacrum during loading with 250 N/1.5 Nm was not different among the three groups (sacroiliac: 1.2 mm, range, 0.6-1.9; cemented: 0.7 mm, range, 0.5-1.3; transsacral: 1.1 mm, range, 0.6-2.3) (p = 0.940). Screw subsidence was less in the cemented group (3.0 mm, range, 1.2-3.7) compared with the sacroiliac (5.7 mm, range, 4.7-10.4) or transsacral group (5.6 mm, range, 3.8-10.5) (p = 0.031). There was no difference with the numbers available in the median number of cycles needed until failure; this was 2921 cycles (range, 2586-5450) in the cemented group, 2570 cycles (range, 2500-5107) for the sacroiliac specimens, and 2578 cycles (range, 2540-2623) in the transsacral group (p = 0.153). The cemented group absorbed more energy before failure (8.2 × 105 N*cycles; range, 6.6 × 105-22.6 × 105) compared with the transsacral group (6.5 × 105 N*cycles; range, 6.4 × 105-6.7 × 105) (p = 0.016). There was no difference with the numbers available in terms of fracture site motion (sacroiliac: 2.9 mm, range, 0.7-5.4; cemented: 1.2 mm, range, 0.6-1.9; transsacral: 2.1 mm, range, 1.2-4.8). Probability values for all between-group comparisons were greater than 0.05. CONCLUSIONS: The addition of cement to standard sacroiliac screw fixation seemed to change the mode and dynamics of failure in this cadaveric mechanical model. Although no advantages to cement were observed in terms of screw motion or cycles to failure among the different constructs, a cemented, two-screw sacroiliac screw construct resulted in less screw subsidence and greater energy absorbed to failure than an uncemented single transsacral screw. CLINICAL RELEVANCE: In osteoporotic bone, the addition of cement to sacroiliac screw fixation might improve screw anchorage. However, larger mechanical studies using these findings as pilot data should be performed before applying these preliminary findings clinically.

[Van Neck-Odelberg disease. Report of two cases]. / A van Neck-Odelberg-betegség bemutatása két eset kapcsán.

Osteochondritis ischiopubica or van Neck-Odelberg disease is characterized by atypical ossification of the ischiopubic synchondrosis. Clinical symptoms are usually pain, limping and limited range of motion of the hip joint. Radiologic images may be confused with the possibility of fracture, tumor or inflammation. In some cases it may be difficult to set up the accurate diagnosis, and during the diagnostic process it is essential that van Neck-Odelberg disease should be considered. In this paper the authors draw attention to this rare disorder and they present the history of two patients who posed diagnostic difficulties.

Estudo comparativo por ressonância magnética de púbis entre atletas e sedentários assintomáticos / Comparative study between the pubis of asymptomatic athletes and non-athletes with MRI

OBJETIVO: Comparar os achados na ressonância magnética do púbis de atletas profissionais de futebol, sem histórico ou clínica de pubalgia, com sedentários também assintomáticos, determinando a prevalência de alterações compatíveis com sobrecarga púbica. MÉTODOS: Dezenove atletas profissionais de futebol, sem queixas álgicas na região púbica, e 17 sedentários, também assintomáticos, foram submetidos à ressonância magnética do púbis. Os resultados dos exames foram analisados quanto à presença de alterações degenerativas, edema medular ósseo e tendinopatia, comparando ambos os grupos estudados. RESULTADOS: Foi encontrada alta prevalência de edema ósseo e tendinopatia, bem como alterações degenerativas da sínfise púbica no grupo de atletas, encontrando-se valores maiores de odds ratio e risco relativo, com significância estatística na população estudada. CONCLUSÃO: Atletas profissionais de futebol apresentam maior risco de desenvolver alterações na região púbica, evidenciadas na ressonância magnética, se comparados a indivíduos sedentários. Estes achados não são obrigatoriamente causa de pubalgia, estando provavelmente relacionados a esforço intenso.

OBJECTIVE: To compare the magnetic resonance imaging findings of the pubis of professional soccer players, without history of or clinical groin pain, and non-athletes, also without symptoms, determining the prevalence of changes compatible with pubic overload. METHODS: Nineteen professional soccer players without complaints of groin pain and seventeen non-athletes, also asymptomatic, underwent pubic magnetic resonance images. Exam findings were analyzed for the presence of degenerative changes, medullar edema and tendinopathy, comparing both groups. RESULTS: High prevalence of bone edema, tendinopathy and degenerative findings in the pubic symphysis was seen in athletes, with statistically significant higher odds ratios and relative risk for the population studied. CONCLUSION: Professional soccer players are at a higher risk for developing changes in the pubic region, evidenced in magnetic resonance images, when compared to non-athletes. Those findings are not necessarily related to groin pain, and are probably related to intense stress.

Microstructural insight into pedestrian pelvic fracture as assessed by high-resolution computed tomography.

Pelvic and femoral neck bone surface strains were recorded in five full-body human cadaver vehicle-pedestrian impacts. Impacts were performed at 40 km/h using automotive front ends constructed to represent those used in previously reported finite element simulations. While experimental kinematics and bone strains closely matched model predictions, observed pelvic fractures did not consistently agree with the model, and could not be solely explained by vehicle geometry. In an attempt to reconcile injury outcome with factors apart from vehicle design, a proxy measure of subject skeletal health was assessed by high-resolution quantitative computed tomography (HRqCT) of the femoral neck. The incidence of hip/pelvis fracture was found to be consistent with low volumetric bone mineral density and low trabecular bone density. This finding lends quantitative support to the notion that healthy trabecular architecture is crucial in withstanding non-physiological impact loads. Furthermore, it is recommended that injury criteria used to assess vehicle safety with regard to pedestrians consider the increased susceptibility of elderly victims to pelvic fracture.

Narrow pubic arch and increased risk of failure for vaginal hysterectomy.

OBJECTIVE: The purpose of this study was to evaluate the risk factors involved in failed vaginal hysterectomies. METHODS: Data on all vaginal hysterectomies performed by a single gynecologic surgeon were collected prospectively. Patients requiring pelvic floor repair were excluded. Any procedure converted to the abdominal approach was classified as a failed vaginal hysterectomy and comprised the study group. For every woman who had a failed vaginal hysterectomy, the next 2 women who had successful vaginal hysterectomies immediately after the failed vaginal hysterectomy were taken as controls. Risk factors such as age, parity, body weight, surgical indication, uterine size, presence of leiomyomata in the anterior lower uterine segment, previous pelvic surgeries, abdominopelvic adhesions, location and length of cervix, narrow pubic arch, intraoperative complications such as bleeding requiring transfusion, visceral injury, nulliparity, and adnexal removal were compared between groups. RESULTS: We compared 25 failed vaginal hysterectomies with 50 controls whose procedures were completed successfully through the vagina. Among all the factors gynecologists can assess preoperatively, only the presence of a narrow pubic arch increased the risk of failure for vaginal hysterectomy (odds ratio [OR] 4.1; 95% confidence interval 1.32-12.69). Intraoperative bleeding with transfusion was also found as an independent cause for conversion to laparotomy (OR 7.37; 95% confidence interval 1.75-31.06). CONCLUSION: Women with a narrow pubic arch are not good candidates for vaginal hysterectomy. The most common unpredictable cause for conversion to laparotomy from the vaginal approach is intraoperative bleeding requiring transfusion. LEVEL OF EVIDENCE: II-2

Osteomielitis en un cuadro de osteopatía púbica / Osteomyelitis pubis in a osteitis pubis case

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Osteoporosis in 5 elderly women with pubic osteolysis.

5 elderly women developed pubic osteolysis after spontaneous fracture of the pubic bone. Radiographs showed gradual progression of the osteolysis, followed by callus formation, and bone union after 4-5 months. Bone mineral density was low in all patients. White blood cell count, erythrocyte sedimentation rate, and C-reactive protein were normal. Urine deoxypyridinoline was high, but serum osteocalcin normal. Elderly women with spontaneous fractures and osteolysis of the pubic bone should be considered for evaluation of osteoporosis and treatment.

Risk factors for recurrent stress fractures in athletes.

Our aim was to identify factors predisposing athletes to multiple stress fractures, with the emphasis on biomechanical factors. Our hypothesis was that certain anatomic factors of the ankle are associated with risk of multiple stress fractures of the lower extremities in athletes. Thirty-one athletes (19 men and 12 women) with at least three separate stress fractures each, and a control group of 15 athletes without fractures completed a questionnaire focusing on putative risk factors for stress fractures, such as nutrition, training history, and hormonal history in women. Bone mineral density was measured by dual-energy x-ray absorptiometry in the lumbar spine and proximal femur. Biomechanical features such as foot structure, pronation and supination of the ankle, dorsiflexion of the ankle, forefoot varus and valgus, leg-length inequality, range of hip rotation, simple and choice reaction times, and balance in standing were measured. There was an average of 3.7 (range, 3 to 6) fractures in each athlete, totaling 114 fractures. The fracture site was the tibia or fibula in 70% of the fractures in men and the foot and ankle in 50% of the fractures in women. Most of the patients were runners (61%); the mean weekly running mileage was 117 km. Biomechanical factors associated with multiple stress fractures were high longitudinal arch of the foot, leg-length inequality, and excessive forefoot varus. Nearly half of the female patients (40%) reported menstrual irregularities. Runners with high weekly training mileage were found to be at risk of recurrent stress fractures of the lower extremities.