Periacetabular osteotomy using computed tomography-based navigation: preoperative planning and accuracy evaluation.

PURPOSE: Since 2011, we have used computed tomography (CT)-based navigation to perform safe and accurate rotational acetabular osteotomy (RAO) for treating developmental dysplasia of the hip. We developed a new method with four fiducial points to improve the accuracy of a published technique. In this study, we introduced a new method to achieve reorientation in accordance with planning and evaluated its accuracy. METHODS: This study included 40 joints, which underwent RAO used CT-based navigation. In 20 joints, reorientation was confirmed by touching the lateral aspect of the rotated fragment with navigation and checking whether it matched the preoperative plan. A new fiducial point method was adopted for the remaining 20 joints. To assess the accuracy of the position of the rotated fragment in each group, postoperative radial reformatted CT images were obtained around the acetabulum and three-dimensional evaluation was performed. The accuracy of acetabular fragment repositioning was evaluated using the acetabular sector angle (ASA). RESULTS: The absolute value of ΔASA, which represents the error between preoperative planning and the actual postoperative position, was significantly smaller in the new fiducial method group than the previous method group in the area from 11:30 to 13:30 (p < 0.05). The Harris Hip Score at 1 year after surgery did not differ significantly between the previous and new fiducial point methods. CONCLUSION: The new fiducial point method significantly reduced reorientation error in the superior-lateral area of the acetabulum: significantly fewer errors and fewer cases of under-correction of lateral acetabular coverage were recorded. The four-reference fiducial method facilitates reorientation of the acetabulum as planned, with fewer errors. The effect of the improved accuracy of the fiducial point method on clinical outcomes will be investigated in the future work.

Transition of Caregiver Perceptions after Pediatric Neuromuscular Scoliosis Surgery.

Introduction: Spinal fusion for children with neuromuscular scoliosis has been known to improve sitting balance and quality of life as well as for high caregiver satisfaction. However, most studies performed were single surveys, and it remains unclear whether high satisfaction levels are maintained. Thus, in this article, we report the short- and medium-term improvements in caregiver standing assessment after neuromuscular scoliosis surgery in children with Gross Motor Function Classification System (GMFCS) level IV or V. Methods: In total, 18 patients with GMFCS levels IV and V were included in this study. The underlying diseases were typical cerebral palsy in 12 cases, chromosomal abnormalities in 5 cases, and congenital myopathy in 1 case. The median age at the time of surgery was 14.5 years. The medians for the first and second follow-up surveys were after 1.4 and 5.9 years, respectively. All the patients had undergone posterior spinal fusion, whereas 12 had undergone pelvic fixation. These patients were assessed using a caregiver questionnaire, in addition to patient demographic data and radiographic assessments. Results: The median BMI was 15.4 kg/m2 preoperatively, 16.6 kg/m2 at the first survey, and 17.1 kg/m2 at the second survey. The main Cobb angles were 97.5°, 36.5°, and 37.0° and the spino-pelvic obliquity angles were 22.5°, 6.0°, and 6.5° preoperatively, at the first survey and at the second survey, respectively. In the questionnaire, most domains were rated similarly in the first and second surveys, but the ratings for the "children's QOL" and "digestion and defecation" domains were noted to increase, while that for the "transfer" and "satisfaction with treatment" domains have decreased. Conclusions: Neuromuscular scoliosis surgery in children has been associated with extremely high treatment satisfaction in the early postoperative period. However, some caregivers showed a decline in the "transfer" and "treatment satisfaction" domains over time.

Corrective osteotomy for complex tibial deformity in a patient with hereditary vitamin D-resistant hypophosphatemic rickets (HVDRR) using CT-based navigation system and 3D printed osteotomy model.

Planning a three-dimensional (3D) osteotomy using computed tomography (CT) data is useful especially in cases with complex deformities. Furthermore, CT-based navigation system allows the preoperative virtual planning to be replicated in actual surgery. However, one disadvantage when using navigation systems is that when osteotomies are performed on tracker-attached bone, the bone fragments on the side that were cut away cannot be tracked. This is especially problematic when performing multiple osteotomies on bones with complex deformities. We solved this problem by creating a 3D printed bone model that can be referenced intraoperatively and used in combination with the navigation system. We applied these techniques to perform segmental corrective osteotomy for a complex tibial deformity with intramedullary nail (IMN) fixation case of hereditary vitamin D-resistant hypophosphatemic rickets (HVDRR) in an adult man. Due to the patient's history of multiple surgeries, the affected tibia had a narrow and partially closed medullary canal. Therefore, we planned to use an IMN for correction and fixation of tibial deformity to protect the thin and stretched skin around the deformed tibia. With the assistance of CT-based navigation, we could perform an accurate three-dimensional tibial osteotomy. Moreover, we could perform accurate preparation of closed medullary canal for the IMN placement by referring to the 3D printed bone models. Six months after the operation, the bone union at the osteotomy sites was confirmed and the patient was able to return to his normal life and work.

Inflammation and nutrition based screening tests for detection of infection in cases of rapid hip destruction.

Preoperative diagnosis of infection is important for appropriate surgical treatment of patients with rapid hip destruction (RHD). We investigated whether test results, including inflammatory and nutritional markers, could be used to accurately differentiate infectious and non-infectious RHD. Fifty patients with RHD who underwent total hip arthroplasty within a year of onset were observed. Infectious RHD was defined as ≥ 2 positive serological inflammatory, microbiological, or pathological evaluations. The albumin to globulin ratio (AGR), C-reactive protein (CRP)/albumin ratio (CAR), Glasgow prognostic score (GPS), modified GPS (mGPS), prognostic nutritional index (PNI), geriatric nutritional risk index (GNRI), and platelet to lymphocyte ratio (PLR) were calculated from the blood test results. In the infectious group, the white blood cell count, platelet count, CRP level, erythrocyte sedimentation rate, CAR, GPS, mGPS, and PLR were significantly higher, while the albumin level, AGR, PNI, and GNRI were significantly lower. The CRP and albumin levels showed the highest sensitivity (1.00 for both; specificity of 0.87 and 0.73, respectively) in diagnosing infectious RHD. Combining these measurements (CAR) increased the specificity to 0.92. The accuracy of other nutritional assessments was good. Thus, nutritional assessment as well as conventional assessment of the inflammatory response can improve the accuracy of preoperative diagnosis of infectious RHD.

Accuracy of Computer Navigation-Assisted Arthroscopic Osteochondroplasty for Cam-Type Femoroacetabular Impingement Using the Model-to-Image Registration Method.

BACKGROUND: Precise osteochondroplasty is important in arthroscopic hip surgery for cam-type femoroacetabular impingement (FAI). Although computer-assisted surgery with a navigation system may enhance the accuracy of arthroscopic osteochondroplasty, few clinical studies have assessed its accuracy. PURPOSE: To evaluate the accuracy of arthroscopic osteochondroplasty by a computed tomography (CT)-based navigation system for cam-type FAI, using 3-dimensional (3D) reconstruction with more detail compared with previous methods. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Twenty patients (14 men and 6 women) who underwent navigation-assisted arthroscopic surgery for cam-type FAI were included. The preoperative 3D model of the femur was constructed from each patient's CT data, and a planned model with virtual cam resection was generated. A femoral model was reconstructed from CT data postoperatively. The 3 models for each patient were overlaid using a 3D model registration method. Then, the contours of the bone resection area of each model were compared by measuring them. To measure the deviation between planned and actual bone resections, 4 cross-sectional images of the 3 femoral models were set at one-quarter intervals from the femoral head radius. All measurements were based on clockface lines set around the femoral neck axis at 30-minute intervals. Differences between the planned and postoperative contour lines were deemed resection deviations. RESULTS: All cam resections were performed in the anterior half of the region of interest. Therefore, only the anterior half (48 points) of the 96 points per case were analyzed. In 876 (91.3%) points of the total measurement points (960 points/20 cases), the error in resection depth was within 3 mm. Overresection was observed at 35 (3.6%) points and underresection at 49 (5.1%) points. The observed maximum deviations from the planned models were 6.3 mm overresection and -7.1 mm underresection. The alpha angles of the postoperative model at the posterior 9- to 3-o'clock position were <55° in all patients. CONCLUSION: Navigation-assisted arthroscopic osteochondroplasty showed favorable accuracy. Underresection was more frequent than overresection on the anterosuperior side of the femur, despite assistance of the navigation system.

Application of Ultrasonography During Sternocleidomastoid Muscle Release for Congenital Muscular Torticollis: A Case Report.

CASE: We report a 4-year-old girl with congenital muscular torticollis (CMT) who was treated with sternocleidomastoid muscle (SCM) tenotomy using ultrasonography (US). Prior to the surgery, US was utilized to identify the clavicle and sternum branches of the SCM, sternohyoid muscles, internal jugular vein, and common carotid artery. Then, local anesthesia was injected into the layer between the fascial sheath of the SCM and carotid sheath to reduce bleeding and avoid vascular injury. During surgery, the SCM dissection was carefully conducted under US guidance to avoid vascular injury. No residual of SCM dissection and improvement of neck motion were confirmed before the skin closure. Postoperative course was good with no obvious complications in this patient. CONCLUSION: The intraoperative US investigation during SCM tenotomy is a useful procedure that provides vital information about dissection area of SCM and orientation of internal jugular vein that reduces the risk of insufficient tenotomy and vascular injury.

An automated real-time PCR assay for synovial fluid improves the preoperative etiological diagnosis of periprosthetic joint infection and septic arthritis.

Synovial fluid is important for the preoperative etiological diagnosis of suspected periprosthetic joint infection (PJI) or septic arthritis (SA). GENECUBE, an automated real-time polymerase chain reaction (PCR) assay, was used to detect bacterial mecA (methicillin resistance) and was compared with microbiological cultures for preoperatively diagnosing PJI and SA in 74 patients suspected of these infections and thus earmarked for surgery. PJI and SA were diagnosed in 21 and 6 cases, respectively, using modified ICM 2018 diagnostic criteria. Microbiological cultures determined methicillin-resistant staphylococcus (MRS) as the causative organism in six samples, which were all positive in the GENECUBE assay. Significantly also, the GENECUBE assay detected six MRS infections in culture-negative but infection-diagnosed patients, and in one inconclusive case, suggesting a higher sensitivity of this assay. Compared with microbiological culture, the sensitivity and specificity of the GENECUBE assay for mecAwas 100% and 92.2%, respectively. However, GENECUBE also produced invalid results in three cases, suggesting possible PCR inhibitors in the synovial fluid samples. We additionally validated the accuracy of pan-bacterial real-time PCR targeting 16S rRNA and other tests. Pan-bacterial real-time PCR was as effective as preoperative bacterial culture testing, although the α-defensin assay had the highest sensitivity at 100%. Hence, fully automated real-time PCR targeting of the bacterial mecA gene improves the etiological diagnosis of PJI and SA by reducing the testing time and lowering the false-positive detection rates. A screening approach for α-defensin followed by bacterial mecA gene testing in synovial fluids is therefore a more efficient method of preoperatively diagnosing PJI and SA.

Influence of Hydroxyapatite Coating for the Prevention of Bone Mineral Density Loss and Bone Metabolism after Total Hip Arthroplasty: Assessment Using 18F-Fluoride Positron Emission Tomography and Dual-Energy X-Ray Absorptiometry by Randomized Controlled Trial.

BACKGROUND: Hydroxyapatite- (HA-) coated implants tend to achieve good osteoinductivity and stable clinical results; however, the influence of the coating on the prevention of bone mineral density (BMD) loss around the implant is unclear. The purpose of this randomized controlled trial was to evaluate the effectiveness of HA-coated implants for preventing BMD loss and to determine the status of bone remodeling after total hip arthroplasty (THA), making comparisons with non-HA-coated implants. METHODS: A total of 52 patients who underwent primary THA were randomly allocated to HA and non-HA groups. BMD was measured by dual-energy X-ray absorptiometry (DEXA) at 1 week postoperation to form a baseline measurement, and then 24 weeks and 48 weeks after surgery. The relative change in BMD was evaluated for regions of interest (ROIs) based on the Gruen zone classifications. 18F-fluoride positron emission tomography (PET) was performed at 24 weeks postsurgery, and the maximum standardized uptake values (SUVmax) were evaluated in the proximal (HA-coated) and distal (non-HA-coated) areas in both groups. RESULTS: There were significant differences in BMD loss in ROIs 3 and 6 (p = 0.03), while no significant difference was observed in ROI 7 at either 24 or 48 weeks postsurgery. There was no significant correlation between PET uptake and BMD (24 or 48 weeks) in either group. CONCLUSION: The influence of a HA coating in terms of BMD preservation is limited. No significant correlation was found between BMD and SUVmax measured by PET, either with or without the use of a HA coating.

Disrupted cortico-ponto-cerebellar pathway in patients with hemimegalencephaly.

OBJECTIVE: Cerebellar dysmaturation and injury is associated with a wide range of neuromotor, neurocognitive and behavioral disorders as well as with preterm birth. We used diffusion tensor MR imaging to investigate a disruption in structural cortico-ponto-cerebellar (CPC) connectivity in children with infantile-onset severe epilepsy. METHODS: We performed CPC tract reconstructions in 24 hemimegalencephaly (HME) patients, 28 West syndrome (WS) of unknown etiology patients, and 25 pediatric disease control subjects without a history of epilepsy nor brain abnormality on MRI. To identify the CPC tract, we placed a seeding ROI separately in each right and left cerebral peduncle. We evaluated the distribution patterns of the CPC tracts to the cerebellum and their correlation with clinical findings. RESULTS: In control and WS of unknown etiology groups, both sides' CPC tracts descended to bilateral hemispheres in 20 (80.0%) and 21 (75.0%); mixed (bilateral on one side and unilateral on the other side) in five (20.0%) and five (17.9%); and unilateral in zero (0.0%) and two (7.1%), respectively. However, in the HME, both sides' CPC tracts descended to bilateral hemispheres in four (16.7%); mixed in 13 (54.1%); and unilateral in seven (29.2%). These CPC patterns differed significantly between the HME and other groups (p < 0.001). Among HME patients, those with a unilateral cerebellar distribution on both sides had significantly earlier seizure onset (p = 0.049) and more frequent seizures (p = 0.052) at a trend level compared to those with bilateral and mixed distributions. CONCLUSION: Disrupted CPC tracts were observed more frequently in HME patients than in WS of unknown etiology patients and controls, and they may be correlated with earlier seizure onset and more frequent seizures in HME patients. DTI is a useful and non-invasive method for speculating the pathology in the developing brain.

Mechanical Strength of the Proximal Femur After Arthroscopic Osteochondroplasty for Femoroacetabular Impingement: Finite Element Analysis and 3-Dimensional Image Analysis.

PURPOSE: To examine the influence of femoral neck resection on the mechanical strength of the proximal femur in actual surgery. METHODS: Eighteen subjects who received arthroscopic cam resection for cam-type femoroacetabular impingement (FAI) were included. Finite element analyses (FEAs) were performed to calculate changes in simulative fracture load between pre- and postoperative femur models. The finite element femur models were constructed from computed tomographic images; thus, the models represented the shape of the original femur, including the bone resection site. Three-dimensional image analysis of the bone resection site was performed to identify morphometric factors that affect strength in the postoperative femur model. Four oblique sagittal planes running perpendicular to the femoral neck axis were used as reference planes to measure the bone resection site. RESULTS: At the transcervical reference plane, both the bone resection depth and the cross-sectional area at the resection site correlated strongly with postoperative changes in the simulated fracture load (R2 = 0.6, P = .0001). However, only resection depth was significantly correlated with the simulated fracture load at the reference plane for the head-neck junction. The resected bone volume did not correlate with the postoperative changes in the simulated fracture load. CONCLUSIONS: The results of our FEA suggest that the bone resection depth measured at the head-neck junction and transcervical reference plane correlates with fracture risk after osteochondroplasty. By contrast, bone resection at more proximal areas did not have a significant effect on the postoperative femur model strength in our FEA. The total volume of resected bone was also not significantly correlated with postoperative changes in femur model strength. CLINICAL RELEVANCE: This biomechanical study using FEA suggest that there is a risk of femoral neck fracture after arthroscopic cam resection, particularly when the resected lesion is located distally.

Difference in Postoperative Periprosthetic Bone Mineral Density Changes Between 3 Major Designs of Uncemented Stems: A 3-Year Follow-Up Study.

BACKGROUND: Although few studies have examined the direct effect of stress shielding on clinical outcomes, periprosthetic bone loss due to stress shielding is still an issue of concern, especially when physicians perform uncemented total hip arthroplasty (THA) in younger patients. Differences in femoral stem design may affect the degree of postoperative stress shielding. Therefore, the characteristics of the behavior for stress shielding of each type of femoral stem should be determined. This study compares differences in bone mineral density (BMD) change in the femur after primary THA between 3 major types of uncemented stems. METHODS: Among a total of 89 hips, 26 hips received THA with a fit-and-fill type stem (VerSys Fiber Metal MidCoat; Zimmer, Inc, Warsaw, IN), 32 hips received a tapered rectangular Zweymüller-type stem (SL-Plus; Smith & Nephew Inc, Memphis, TN), and 31 received a tapered wedge-type stem (Accolade TMZF; Stryker Orthopaedics, Mahwah, NJ). BMD measurements were performed with a HOLOGIC Discovery device (Hologic Inc, Waltham, MA). RESULTS: BMD in the medial-proximal femur was maintained for 3 years after THA in the group with the tapered wedge-type stem. BMD in the lateral-proximal femur was maintained for 3 years after THA in the group with the Zweymüller-type stem. There were no significant differences in the Harris Hip Score among the 3 stem groups preoperatively and 1, 2, and 3 years after surgery. CONCLUSION: There are clear differences in postoperative BMD loss of the proximal femur among these 3 commonly used uncemented stems.

Giant cell tumour of the femur in a 9-year-old girl, resulting in severe leg length discrepancy.

Giant cell tumour of bone (GCTB) is a rare benign tumour noted before physeal closure. GCTB cases in patients younger than 10 years are especially uncommon. The authors report the case of a 9-year-old girl with a GCTB of the distal femur. After initial intralesional excision and curettage of the tumour, local recurrence occurred, which needed two more additional surgeries to treat. The primary tumour and the local relapse invaded the growth plate of the right distal femur, leading to growth disturbance of the femur and requiring leg lengthening using Ilizarov apparatus. Surgeons should note the possibility of this rare condition while treating radiographic lytic lesions even in skeletally immature patients. The occurrence of late limb length discrepancy would be more likely in younger patients.

Novel 2 radiographical measurements for atlantoaxial instability in children with Down syndrome.

STUDY DESIGN: A retrospective case-control study. OBJECTIVE: To assess the usefulness and reproducibility of 2 novel safe and simple radiographical measurements for atlantoaxial instability in children with Down syndrome. SUMMARY OF BACKGROUND DATA: In pediatric atlantoaxial instability, early diagnosis is important for improved outcomes because of poor postoperative recovery in progressed neurological symptoms. Conventional dynamic radiography of the cervical spine is associated with a potential risk of worsening neurological symptoms. METHODS: We retrospectively reviewed the medical records of 50 patients (24 boys and 26 girls) with atlantoaxial instability associated with Down syndrome. Of the 50 children, 11 had undergone and 4 had been scheduled for surgery (surgical group). In this investigation, in addition to the atlas-dens interval (ADI) and space available for spinal cord (SAC), we measured C1 inclination angle and C1/4 SAC ratio on lateral radiographs of the cervical spine in the neutral position. To assess the diagnostic abilities of these indices to determine indication for surgery, receiver operating characteristic analysis of each index was performed, and their diagnostic abilities were compared using the area under the receiver operating characteristic curve. Moreover, we assessed reproducibility of our 2 proposed indices. RESULTS: The discriminatory abilities of C1/4 SAC ratio (area under the receiver operating characteristic curve, 1.00) and C1 inclination angle (0.91) were comparable with those of ADI (0.98) and SAC (0.95). For the interobserver and intraobserver reliability of the novel indices, the correlation coefficients were in the range from 0.88 to 0.99. Correlation was observed between the ADI and C1/4 SAC ratio (r = 0.507, P < 0.01) and between the ADI and C1 inclination angle (r = 0.407, P < 0.01). CONCLUSION: The diagnostic abilities of the 2 novel radiographical measurements were comparable with those of ADI and SAC. Moreover, these novel measurements can be obtained safely on lateral radiographs of the cervical spine in the neutral position. LEVEL OF EVIDENCE: 4.

A case of aortic dissection caused by blunt chest trauma.

A 74-year-old woman was struck by a car travelling at about 50 km/h. On arrival at hospital, a CT scan showed dissection of the ascending and descending aorta. She collapsed and died suddenly 8h later. At autopsy, there was massive bleeding into the left pleural cavity, ruptures of the pericardium and right ventricle, and a type A thoracic aortic dissection. The cause of death was haemorrhagic shock due to rupture of the pericardium and delayed rupture of the right ventricle following trauma to the chest. The thoracic aortic dissection was not the direct cause of death although histological examination did reveal that it occurred in the accident. Traumatic aortic dissection is rare although traumatic aortic rupture is a major cause of death after blunt chest trauma. This paper discusses the mechanisms, and factors involved in aortic dissection caused by blunt trauma.