Analysis of computed tomography-based infra-acetabular morphometry to assess the feasibility of infra-acetabular screws

INTRODUCTION

The number of pelvic fractures based on osteoporosis has been increasing. The infra-acetabular screw (IAS), which connected both osseous columns, is a safe method of screw placement going through the infra-acetabular corridor (IAC). However, the specifics of the anatomy of IAC have been far from completely understood, especially in the Asian population. The purpose of our study was to reveal the details of the IAC using computed tomography (CT) data.

MATERIALS AND METHODS

Traumatized in-patients having pelvic CT scans from 2014 to 2016 were enrolled. Pediatric and adult patients with pelvic fractures and hip prostheses were excluded. The male/female ratio and distribution of patients' age were equalized manually; 40 male and 40 female patients were included. The IAC was measured on the plane of the inlet view (25° caudal) in multi-planar reconstructed CT images.

MEASUREMENTS

infra-acetabular diameter (IAD), anterior-posterior length of the IAC (APL), length from the starting point of the IAC to the medial edge of the pelvis (LME), length from the starting point of the IAC to the top of the pubic symphysis (LPS), and tilting on inlet plate (TIP).

RESULTS

Age was 59 ± 22 (mean ± SD). Height was 159 ± 11 cm, and body mass index (BMI) was 22.9 ± 4.1. IAD, APL, LME, LPS, and TIP was 4.0 ± 1.3 mm, 89.5 ± 7.1 mm, 8.7 ± 3.6 mm, 57.8 ± 4.8 mm, and 4.7 ± 5.2°, respectively. Over 20% of corridors (35 of 160) were not feasible for IAS placement, because of inadequate width (less than 3.0 mm). Nine corridors (5.6%) had curvature in IAC, which meant technically demanding to insert IAS. There was no difference in IAD between male and female patients, while APL, LME, LPS, and TIP had sex-related differences.

CONCLUSIONS

Surgeons should pay attention to the fact that over 20% of IACs are not feasible for infra-acetabular screw placement even with the perfect reduction of fragments when treating acetabular fractures.

Histological evaluation of the acetabular labrum after bipolar hip hemiarthroplasty: a case report

We report herein the microstructure of the acetabular labrum obtained from a patient with stem loosening but without bipolar cup migration who had undergone hemiarthroplasty for femoral neck fracture 18 years ago. We used light and scanning electron microscopy to investigate the influence of bipolar cup on acetabular labrum in vivo. Deparaffinized blocks were treated with 2 N NaOH to digest the cell matrix, allowing the collagen fibers, constituting the acetabular labrum, to be observed under scanning electron microscopy. Although chondrocyte atrophy was seen, the basic structure was not different from the normal tissue images of the elderly. However, in the deep part of the acetabular labrum, there was an area that was not stained with Alcian blue observed with light microscopy, and there was an amorphous tissue without type II collagen fibrils observed with scanning electron microscopy. These findings proved that the acetabular labrum has partially degenerated over the long term after bipolar hemiarthroplasty, and that the acetabular labrum can survive in vivo in such a condition. Given that hemiarthroplasty has a possibility to preserve the face-to-face tissue in the long term in vivo, it may be one of the valuable options for modern or future joint reconstruction surgery.

Long-term disease control by trabectedin in a patient with dedifferentiated liposarcoma: A case report

RATIONALE

Trabectedin is an antitumor drug considered to be effective for liposarcoma, leiomyosarcoma, and translocation-related sarcoma. Concerning liposarcoma subtypes, evidence of the efficacy of trabectedin for dedifferentiated liposarcoma (DDLPS) is poor, whereas it is known to have high efficacy against myxoid liposarcoma. Moreover, there are few reports of long-term trabectedin treatment of cases of DDLPS. Here, we present a case of advanced metastatic DDLPS that achieved long-term disease control by trabectedin treatment.

PATIENT CONCERNS

A 68-year-old man presented with a mass in his back. Magnetic resonance imaging showed a tumorous mass in his back which exhibited low intensity on T1-weighted and high intensity on T2-weighted images.

DIAGNOSIS

The mass was diagnosed as DDLPS by open biopsy.

INTERVENTIONS

The patient underwent gemcitabine+docetaxel combination therapy followed by pazopanib and eribulin; all these therapies failed to halt disease progression. Subsequently, we changed the regimen to trabectedin as fourth-line therapy.

OUTCOME

The patient achieved stable disease for approximately 18 months during 11 cycles of trabectedin therapy.

LESSONS

Trabectedin should be considered as a treatment option for DDLPS even in cases of numerous failed prior chemotherapy regimens.

Enhancement of the effects of intermittent parathyroid hormone (1-34) by bone morphogenetic protein in a rat femoral open fracture model

Background

Nonunion in cases of open fracture is common. Both bone morphogenetic protein 2 (BMP-2) and parathyroid hormone (PTH) have been used to enhance bone healing. We investigated the combination of BMP-2 and PTH and examined the effects on a rat model of open femoral fractures.

Methods

Group I (n = 11) was implanted with control carrier. Group II (n = 12) was implanted with carrier containing 1 μg of recombinant human BMP-2 (rhBMP-2). Group III (n = 12) was implanted with carrier alone, followed by injections of PTH 1-34. Group IV (n = 11) was implanted with carrier containing 1 μg of rhBMP-2, followed by injections of PTH 1-34. Group V (n = 11) was implanted with carrier containing 10 μg of rhBMP-2. Group VI (n = 11) was implanted with carrier containing 10 μg of rhBMP-2, followed by injections of PTH 1-34. Rats were euthanized after 8 weeks, and their fractured femurs were explanted and assessed by manual palpation, radiographs, micro-computerized tomography, and histological analysis.

Results

Manual palpation tests showed that the fusion rates of groups III (66.7%), IV (63.6%), V (81.8%), and VI (81.8%) were considerably higher than those of group I. Groups V and VI had higher radiographic scores compared to group I. Micro-CT analysis revealed enhanced bone marrow density expressed as bone volume/tissue volume in groups V (61.88 ± 3.16%) and VI (71.14 ± 3.89%) versus group I (58.26 ± 1.86%). A histological analysis indicated that group VI had enhanced remodeling.

Conclusion

The combination of abundant rhBMP-2 and PTH enhanced bone healing and remodeling of newly formed bone in a rat femoral open fracture model.

Cervical alignment after single-level anterior cervical corpectomy and fusion using autologous bone graft without spinal instrumentation for cervical pyogenic spondylitis

BACKGROUND

Subsidence in anterior cervical corpectomy and fusion (ACCF) for cervical degenerative disease (CDD) are constantly observed during the postoperative course. Although kyphotic change of cervical alignment occurred frequently in cervical pyogenic spondylitis (CPS) postoperatively, studies on the postoperative change in segmental angle for CPS are limited. This study aimed to analyze cervical alignment after single-level ACCF using autologous bone graft without spinal instrumentation for CPS compared with that for CDD.

METHODS

Six patients underwent single-level ACCF using autologous bone graft without spinal instrumentation for CPS. The control group included 18 age-matched patients who underwent single-level ACCF using autologous bone graft for CDD without spinal instrumentation for the same duration. Cervical and lateral plain radiographs and computed tomography scans were taken. The Frankel classification was used to assess the neurological status preoperatively, postoperatively, and at 2-year follow-up for CPS.

RESULTS

At 2-year follow-up, the average segmental angle at the fusion level was - 12.2° ± 6.9° for CPS and - 5.2° ± 7.6° for CDD (p = 0.04). Changes in segmental angle at the fusion level were - 7.2 ± 9.0° for CPS and - 1.1° ± 7.1° for CDD (p = 0.02). At 2-year follow-up, the average anterior segmental fusion height was 23.4 ± 1.7 mm for CPS and 29.1 ± 5.1 mm for CDD (p < 0.001). At 2-year follow-up, bone fusion in the CPS group was classified as grade 5 (complete fusion) in 4 patients (66.7%) and grade 4 (probable fusion) in 2 (33.3%). In the CDD group, it was grade 5 in 13 patients (72.2%) and grade 4 in 5 patients (27.8%). Overall, both groups achieved 100% bone fusion rate. The Frankel classification in all CPS cases improved or leveled off.

CONCLUSION

Progression of segmental kyphosis angle and subsidence of graft bone were observed postoperatively on all CPS cases. However, the neurological recovery and bone union were satisfactory.

The position of the spinal cord relative to the vertebrae in adolescent idiopathic scoliosis

We aimed to clarify the position of the spinal cord relative to the vertebra in patients with Lenke type 1 adolescent idiopathic scoliosis (AIS). In all, 35 patients with Lenke type 1 AIS who underwent posterior spinal fusion using a pedicle screw construct and preoperative computed tomography (CT) after myelography were recruited. The following radiological parameters were measured on preoperative CT myelography: spinal cord-vertebral (SV) angle, entry-spinal cord distance (ESD), ESD-X, ESD-Y, spinal cord-pedicle (SP) angle, and rotation angle (RAsag). The SV and SP angles were the smallest at T9 level, followed by T8 and T7 levels, and tended to increase cranially and caudally. The ESD was the shortest at T9 level, followed by T8 and T10 levels. The ESD-X was the smallest at T9 level, followed by T8 level, while the ESD-Y was the smallest at T10 level, followed by T9 and T8 levels. Mean RAsag increased from T4 to T9 levels and decreased from T9 to T12 levels. The ESD was significantly negatively correlated to RAsag. Among all apical vertebrae, the SV and SP angles were negatively correlated to Cobb angle. The RAsag was positively correlated while the ESD was negatively correlated to the Cobb angle. The spinal cord is close to the vertebrae in the apical vertebral region and far from the vertebrae at the upper and lower thoracic vertebral levels in AIS. Therefore, the potential risk of spinal cord injury by pedicle screw is the highest in the apical vertebral region.

Isolated acetabular revision with femoral stem retention using computed tomography-based navigation

BACKGROUND

In isolated acetabular revision surgery, surgeons must place the cup at an appropriate angle with various retained stem anteversion angles to prevent postoperative dislocation. For accurate acetabular cup position, various navigation systems have been used. Nevertheless, no publications have reported combined cup and stem anteversion and dislocation rates after isolated acetabular revision, especially comparing the use of navigation with manual implantation. Therefore we performed a retrospective comparative study to answer the following questions: (1) What is the combined anteversion after isolated acetabular revision with computed tomography-based navigation? (2) Does navigation improve the accuracy of cup angle and combined anteversion, (3) reduce dislocation rate, and (4) reduce operative time?

HYPOTHESIS

A navigation system makes combined anteversion near the target angle in isolated acetabular revision.

PATIENTS AND METHODS

We conducted a retrospective study of 32 hips in 24 patients who underwent isolated acetabular revision total hip arthroplasty using computed tomography-based navigation system. The control group comprised 8 hips in 8 patients who underwent the same procedure without navigation.

RESULTS

In the navigation group, average Widmer's combined anteversion was 39.0°±8.7° (range, 25.3°-56.6°). Cup positions were 40.3°±2.9° (range, 29.0°-49.0°) for radiographic abduction angle, 24.3°±8.0° (range, 4.6°-42.6°) for radiographic anteversion. In the control group, Widmer's combined anteversion was 47.2°±15.1° (range, 27.0°-74.3°, p=0.048). The average cup positions for radiographic abduction angle and anteversion were 36.7°±8.9° (range, 24.5°-54.9°) and 29.1°±7.3° (range, 17.2°-38.8°), respectively (p>0.05). Widmer's combined anteversion deviated from the target angle by a smaller amount in the navigation group than in the control group: errors in measurement of Widmer's combined anteversion were 7.2°±5.1° (range, 0.74°-19.6°) in the navigation group and 13.9°±11.1° (range, 3.6°-37.3°) in the control group (p=0.135). Postoperative dislocation occurred in none of the 32 hips (0%) in the navigation group and in one of the 8 hips (12.5%) in the control group (p=0.2).

DISCUSSION

Using the navigation system, combined anteversion is made near the target angle in isolated acetabular revision surgery and more accurately than manual implantation. These results should be considered as preliminary since this is a limited cohort, but it brings new knowledge in navigation considering the very limited number of series using of navigation in isolated cup revision of total hip arthroplasty. In addition this is the first study to investigate combined cup and stem anteversion in isolated acetabular revision. The use of CT-scan is helpful to diagnose error in stem anteversion and to adapt the orientation of the new cup.

LEVEL OF EVIDENCE

III, Retrospective case control study.

Effect of intraoperative position in single-level transforaminal lumbar interbody fusion at the L4/5 level on segmental and overall lumbar lordosis in patients with lumbar degenerative disease

The purpose of this study was to investigate the effect of intraoperative positions in single-level (L4-5) transforaminal lumbar interbody fusion (TLIF) on segmental and overall lumbar lordosis (LL) in patients with lumbar degenerative disease. Thirty-eight consecutive patients who had undergone single-segment (L4-5) TLIF with 0° polyetheretherketone (PEEK) cage and pedicle screw fixation were evaluated. Twenty patients underwent surgery on the four-poster type frame with hip flexion at 30° (Group I) and 18 patients were operated on a Jackson spinal table to adjust their hip flexion to 0° (Group II). Preoperative standing, intraoperative prone, and postoperative standing lateral radiographs were obtained in each patient. The overall and segmental LL were analyzed according to the position in which the patients were placed for their operation and results compared between Groups I and II. Intraoperative intervertebral segmental LL at L4-5 and L5-S1 was increased in Group II than in Group I, whereas postoperative intervertebral segmental LL at L4-5 (fused level) was increased LL. In Group I intraoperative intervertebral segmental LL at L4-5 did not achieve sufficient lordosis, whereas postoperative intervertebral segmental LL at L3-4 was increased. The overall spinal alignment was unaffected by the decreased segmental LL in the fused level owing to the compensation of the upper adjacent segments. The more the hip was extended intraoperatively, the more the segmental lordosis increased in the lower lumbar spine. Thus, selecting the appropriate surgical table and hip position are very important. Underachievement of segmental lordosis leads to the acceleration of upper adjacent segment load.

Spinal epidural lipomatosis is associated with liver fat deposition and dysfunction

OBJECTIVE

This study examined the association of spinal epidural lipomatosis (SEL) with liver fat deposition and any other liver dysfunction, except steroid involvement.

PATIENTS AND METHODS

We analyzed 102 patients (62 men and 40 women; mean age 73.3 years) who underwent spinal magnetic resonance imaging (MRI), computed tomography (CT), and myelography for the diagnosis of lumbar spinal canal stenosis between January 2014 and June 2018. Additional data collected included height, weight, body mass index, blood test results (C-reactive protein, albumin, total bilirubin, aspartate aminotransferase, alanine aminotransferase, gamma-glutamyltransferase [γ-GTP], total cholesterol, neutral fat, amylase, urea nitrogen, creatinine, estimated glomerular filtration rate, uric acid, platelets), the epidural fat-occupying ratio in each vertebra from L1/2 to L5/S1 on MRI, and liver CT values.

RESULTS

In 30 cases, the average occupying ratio of epidural fat was ≥40% (SEL), and in 45 cases, liver CT values were <40 HU (fatty liver). Correlation analysis between average occupying ratio of epidural fat and various measurements showed liver CT value (r = -0.574, P <  0.001), body weight (r = 0.304, P =  0.002), γ-GTP (r = 0.370, P =  0.01), and uric acid (r = 0.201, P =  0.04) to be independent explanatory factors. Multivariate analysis revealed that SEL was associated with liver CT value (odds ratio 0.774, 95% confidence interval [CI] 0.689-0.871) and body weight (odds ratio 1.063, 95% CI 1.016-1.135).

CONCLUSION

There was a strong correlation between epidural fat and liver fat deposits suggesting an association between SEL and systemic fat deposition.

Efficacy of vitamin E for mechanical damage and oxidation of polyethylene rim by stem neck impingement

BACKGROUND

The aim of this study is to determine the influence of crosslinking and addition of 0.3 wt% vitamin E in a polyethylene rim on its mechanical damage and oxidation caused by impingement.

METHODS

Six ultrahigh-molecular weight polyethylene samples were studied (control; crosslinked; vitamin-E containing; crosslinked and vitamin-E containing; aged control; and aged crosslinked and vitamin-E containing). Crosslinking was attained by irradiation with a 300 kGy electron beam; vitamin E incorporation was at 0.3 wt%; and aging was performed through forced oxidation for 14 days. Resistance to impingement was evaluated by stereoscopic observations, three-dimensional measurements, and oxidation measurements by Fourier transform infrared spectroscopy.

FINDINGS

Rim breakage (delamination and fracture) due to impingement was observed only for the aged control specimen. In contrast, crosslinked specimens containing vitamin E showed no failure of the rim after aging. The addition of vitamin E to polyethylene suppressed its oxidation and reduced the oxidation caused by crosslinking or impingement. The impingement resistance of the control sample deteriorated upon oxidation, whereas that of vitamin E-containing crosslinked polyethylene remained high due to the antioxidant property of vitamin E.

INTERPRETATION

Vitamin E-containing polyethylene showed a reduced risk of wear/breakage of polyethylene rims by impingement.

Minimally invasive triangular osteosynthesis for highly unstable sacral fractures: Technical notes and preliminary clinical outcomes

Triangular osteosynthesis involves unilateral L5 iliac posterior instrumentation combined with an iliosacral screw fixation. The aim of this study was to describe this procedure and report the preliminary clinical results in patients with unstable sacral fractures treated with minimally invasive triangular osteosynthesis (MITO). Between 2012 and 2017, 10 patients (6 men and 3 women, mean age, 50 ± 23 years) with sacral fractures were treated with MITO and were followed up for a mean of 15.0 ± 8.5 months in our institution. Classification of sacral fracture, operative time, intraoperative bleeding, timing of full weight bearing, bone union, complications, and clinical outcomes were investigated. Two cases were classified as Denis zone 1, 2 cases as zone 2, and 6 as zone 3. Four patients had Roy-Camille type 1 fracture and 2 patients had type 2. All patients underwent MITO, which involved bilateral lumbopelvic fixation and a uni/bilateral iliosacral screw with stab incisions for percutaneous fixation or central longitudinal incision. The operative time was a mean of 182 ± 64 minutes, and the amount of intraoperative bleeding was a mean of 63 ± 74 g. Full-weight bearing was initiated at a mean of 8.2 ± 2.4 weeks. Eight fractures healed; 1 patient had pulmonary embolism and 1 had implant loosening. Based on Majeed score, 8 patients had "excellent" clinical outcomes, 1 patient had a "good" clinical outcome, and the other had a "fair" clinical outcome. MITO could be less invasive on the soft tissues and be a reliable procedure for bony union. It might provide sufficient stability to accelerate the commencement of post-operative rehabilitation, even in patients with highly unstable sacral fractures.

Ultrastructure and three-dimensional architecture of the anterior cruciate ligament in the knee joints of young and old monkeys

We examined the ultrastructure of the anterior cruciate ligament and assessed age-related changes by comparing the ligaments of young and old monkeys. Ultrathin sections of the anterior cruciate ligament were observed by transmission electron microscopy. The three-dimensional architecture of collagen fibers in the ligament was examined by scanning electron microscopy after tissue specimens were treated with 2 N NaOH to digest the extracellular matrix. At the surface layer of the cruciate ligament in young monkeys, fusiform-shaped fibroblasts actively produced collagen fibrils. The ligament consisted of parallel bundles of dense collagen fibrils of approximately 200 nm in diameter. Collagen fibrils appeared to run linearly. Ligament fibrocytes in the deep layer had a stellate form. Ligament fibrocytes decreased in number and showed marked atrophy in old age. Collagen fibrils had a looser configuration in older monkeys. Despite atrophy of fibroblasts in the deep layer of the anterior cruciate ligament, the area with atrophic fibroblasts in the ligament expands with age, which can likely cause deterioration of and a reduction in collagen fibers. This information can be applied in studies on the cause of the low repair ability of and aging-related changes in the anterior cruciate ligament in humans.

Efficacy of Computed Tomography-Based Navigation for Cup Placement in Revision Total Hip Arthroplasty

Background

Navigation systems are an effective tool to improve the installation accuracy of the cup in primary total hip arthroplasty. This study aimed to evaluate the efficacy of a computed tomography-based navigation system in achieving optimal installation accuracy of implants in revision total hip arthroplasty and to clarify the usefulness of the navigation system.

Methods

We conducted a retrospective study of 23 hips in 23 patients who underwent revision total hip arthroplasty using a computed tomography-based navigation system; the control group comprised 33 hips in 33 patients who underwent revision total hip arthroplasty without a navigation system.

Results

The average cup position with the navigation system was 40.0° ± 3.7° in radiographic abduction angle, 18.8° ± 4.8° in radiographic anteversion, and 41.2° ± 8.9° in combined anteversion; without the navigation system, the average cup position was 38.7° ± 6.1°, 19.0° ± 9.1°, and 33.6° ± 20.5°, respectively. The achievement rate of cup positioning within the Lewinnek safe zone was not significantly different between the navigation group (82.6%) and control group (63.6%). In contrast, the achievement rate of cup positioning within the Widmer combined anteversion guidelines was significantly greater in the navigation group (78.3%) than in the control group (48.0%, p = 0.029). Furthermore, outlier cases in the navigation group had a smaller variance of deviation from the optimal cup position than those in the control group did.

Conclusions

The results show that the use of navigation for revision total hip arthroplasty improved cup positioning and reduced the range of outliers. Improvement of cup placement accuracy influenced the installation of the stem and also improved the achievement rate of combined anteversion. Thus, a computed tomography-based navigation system is very useful for surgeons when placing the cup within the target angle in revision total hip arthroplasty.

Influence of hip center position, anterior inferior iliac spine morphology, and ball head diameter on range of motion in total hip arthroplasty

BACKGROUND

Acetabular component orientation, such as high placement and femoral head diameter influence joint stability in total hip arthroplasty (THA), wherein anterior inferior iliac spine (AIIS) shape could cause femoro-acetabular impingement. Little is known regarding the combined influence of these parameters, particularly in the context of developmental dysplasia of the hip. Therefore we conducted a computer simulation study based on computed tomography (CT) data to determine whether: (1) AIIS shape, (2) high placement of acetabular cups, and (3) ball head diameter influence the range of motion (ROM) after THA.

HYPOTHESIS

The decrease in ROM depends on AIIS shape and the ROM decreases even if the femoral head diameter is increased when high placement of acetabular cups.

PATIENTS AND METHODS

CT data from 14 hips of 14 patients were evaluated. Hips were categorized by Hetsroni classification type I (n=6), type II (n=6), and type III (n=2) depending on AIIS shape. ROM was evaluated using CT-based software. Cups were placed at and 5 and 10mm above the normal hip position. The femoral heads used were 28 (standard simulation), 32, and 36mm in diameter. ROM at impingement was measured under flexion (Flex), internal rotation (IR) at 90° flexion (IR at 90Flex), IR at 45° flexion with a 20° adduction (IR at 45Flex20Add), and external rotation at 10° extension (ER at 10Ext).

RESULTS

The mean ROM standard simulation for Flex, IR at 90Flex, IR at 45Flex20Add and ER at 10Ext were: 119.8±5.4°, 31.0±11.3°, 70.0±11.9°, and 33.0±9.7° for type I; 118.5±5.5°, 31.5±2.9°, 71.3±2.2°, and 33.3±3.3° for type II; and 105.5±13.4°, 21.0±15.6°, 61.0±11.3°, and 34.5±2.1° for type III, respectively. There were no significant differences in the ROMs of each type (Flex, p=0.252; IR at 90Flex, p=0.461; IR at 45Flex20Add, p=0.261; and ER at 10Ext, p=0.655). For the high placement of acetabular cups, ROM increase was restricted despite the femoral head diameter increase.

DISCUSSION

Larger femoral head diameters increased ROM, with a lower increase in type III because of bony impingement. ROM decreased with higher cup placement. Expansion effects were minimal, even with larger ball head diameters, and were further decreased in types II and III. Attention should be paid to AIIS shape because bony impingements occur early with higher acetabular cup placement.

LEVEL OF EVIDENCE

VI Simulation study.

Progressive Osteolysis with Hematoma Following Revision Total Hip Arthroplasty using Hydroxyapatite Mesh: A Case Report

Introduction:

Osteolysis around the prosthesis following total hip arthroplasty (THA) is usually expanded slowly in the mid to long term, not progressive in the short term. Hematoma around the prosthesis is a rare phenomenon after a period of 1 year or more after surgery other than metal on metal THA. In addition, there are no studies reporting that hydroxyapatite (HA) itself has a possibility to cause osteolysis or hematoma after THA. This case has a particular disease phenomenon with three unusual factors, such as progressive osteolysis, hematoma, and HA debris in granulation tissue, following revision THA.

Case Report:

A 79-year-old woman with pain in the left hip joint underwent a revision THA, using HA mesh and ultra high molecular weight polyethylene fiber cable for impaction bone grafting to fill a bone defect in the proximal femur in 2011. There were no abnormal findings clinically or on radiograph until 2014. Moderate osteolysis was observed at the lesser trochanter and the area distal to the greater trochanter on the radiograph in 2015. The synovial fluid culture was negative. On magnetic resonance imaging examination, the margin showed a low-density shell in both the T1- and T2-weighted images, and the inside was a mosaic mass, with mixed low- and high-density are as extending in a multidirectional manner. During surgery, cystic mass covered with a thick membrane was found around the artificial hip joint, and the inside of the capsule was full of solid and fluid hematoma and dark blood. There was no apparent wear and tear debris of the implant. On pathological examination, evidence of chronic hematoma, granulation tissue, and HA debris, interspersed inside the granulation tissue were observed.

Conclusion:

We experienced an extremely rare case with osteolysis and hematoma that progressively expanded in a short period of time after revision THA using HA mesh, which seemed to be caused by, crushed HA and resulted in osteolysis accompanied by hematoma. This case revealed that HA it has a possibility to cause osteolysis or hematoma after THA.

Effect of thoracic kyphosis formation and rotational correction by direct vertebral rotation after the simultaneous double rod rotation technique for idiopathic scoliosis

OBJECTIVE

The objective of the present study was to evaluate the effect of thoracic kyphosis formation and rotational correction by direct vertebral rotation (DVR) after the simultaneous double-rod rotation technique (SDRRT) for idiopathic scoliosis (IS).

PATIENTS AND METHODS

The present study included twelve patients with IS who received SDRRT (SDRRT group) and twelve patients with IS who received DVR after SDRRT (SDRRT + DVR group). We investigated the following parameters preoperatively, postoperatively, and at postoperative 2 years: Cobb angle (PT, MT, T/L, C7-CSVL, AVT, TK (T5-12), LL(L1-S1) RSH, the angle of rotation (RAsag), percent change of RAsag and SRS22 (at postoperative 2 years only).

RESULTS

Preoperatively, the mean main thoracic curve was 58.9 ± 12.4° for the SDRRT group and 59.9 ± 16.0° for the SDRRT + DVR group, which was corrected to 14.6 ± 6.7° and 13.4 ± 4.9° postoperatively. and 14.9 ± 7.1° and 14.3 ± 4.1° at postoperative 2-year follow-up, respectively. Correction rates were 75.4 ± 10.4% and 77.2 ± 8.0 % postoperatively. Thoracic kyphosis increased postoperatively and at postoperative 2-year follow-up in both the SDRRT group and the SDRRT + DVR group. The mean preoperative TK was 11.4 ± 7.3° in the SDRRT group, and 12.8 ± 11.5° in the SDRRT + DVR group, which improved significantly to 24.8 ± 5.2° and 23.6 ± 3.5° postoperatively and 23.3 ± 3.9° and 24.2 ± 6.0° at postoperative 2-year follow-up, respectively. Correction of vertebral rotation as RAsag was significantly better in the SDRRT + DVR group than in the SDRRT group. The mean preoperative RAsag was 19.1 ± 6.7° in the SDRRT group, and 18.3 ± 7.5° in the SDRRT + DVR group, which improved to 13.3 ± 4.3° and 10.1 ± 2.9° postoperatively (P = 0.04) and 13.9 ± 4.0° and 10.6 ± 2.8° at postoperative 2-year follow-up (P = 0.02), respectively.

CONCLUSION

DVR after SDRRT for idiopathic scoliosis allowed for rotation correction without compromising kyphosis formation.

Surrogacy of intermediate endpoints for overall survival in randomized controlled trials of first-line treatment for advanced soft tissue sarcoma in the pre- and post-pazopanib era: a meta-analytic evaluation

Background

Overall survival is the true endpoint for most randomized controlled trials (RCTs) of malignant tumors, whereas progression-free survival (PFS) is considered the most reliable surrogate endpoint for overall survival (OS). The present study aimed to evaluate the correlation between surrogate endpoints and OS in randomized trials of first-line chemotherapy with doxorubicin (DOX), the standard treatment for advanced and metastatic soft tissue sarcomas (ASTS), using a meta-analytic approach.

Methods

In a systematic review, we identified RCTs of first-line chemotherapy for ASTS that compared single-agent doxorubicin (DOX) with other chemotherapy regimens, and were published in English during January 1974–December 2017. A meta-analysis was performed to evaluate the efficacy of first-line treatments for ASTS. Surrogacy of the intermediate endpoints for OS was investigated using weighted linear regression analysis. Correlation strength was examined using the coefficient of determination (R²).

Results

Twenty-seven randomized trials, comprising 6156 patients (3371 patients in the experimental arm and 2785 patients in the DOX arm) were identified. The hazard ratios for OS and PFS showed that the efficacy of treatment for ASTS was not significantly different between standard DOX and experimental treatments. The median OS was significantly prolonged in RCTs published after 2012 when pazopanib was approved for treating ASTS. The median PFS, however, did not differ significantly. The correlation between PFS and OS was moderate (R² = 0.557), but better than that between OS and 3-month PFS, 6-month PFS, and response rate (R² = 0.200, 0.073, and 0.278, respectively). The correlation between PFS and OS tended to be more favorable in RCTs published after 2012 (R² = 0.586 and 0.459, respectively).

Conclusions

The trial-level correlation between PFS and OS was only modest; it tended to be better in RCTs published after 2012. While the effective lines of chemotherapy and the introduction of new drugs prolonged OS but not PFS, PFS is a better surrogate than other intermediate endpoints in the first-line ASTS trials even in the post-pazopanib era. Although this does not negate the need for more reliable surrogate endpoints for OS.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5268-2) contains supplementary material, which is available to authorized users.

Radiographic evaluation of linear wear of bipolar hemiarthroplasty devices in vivo

BACKGROUND

The indications for bipolar hemiarthroplasty (BHA) have been narrowing as those for total hip arthroplasty (THA) have been expanding in cases of femoral neck fracture and initial stages of osteonecrosis of femoral head (ONFH). It is difficult to measure wear in vivo after BHA because the equipment used has a dual bearing system with an inner head inside a metal outer cup. The present study aimed to (1) use a roentgenograph to measure linear wear in vivo after BHA with different acetabular conditions around the bipolar cup, and (2) compare the linear wear of polyethylene between integral bipolar cup (IBC) and Centrax prostheses.

METHODS

From among patients who had undergone BHA in our department after 1996, we analyzed 48 joints with osteoarthritis (OA) and without acetabular cartilage, as well as 25 joints with ONFH of stage 3 or less, in which the acetabular cartilage remains. Two types of bipolar cup prostheses were used: the IBC, which was gamma-sterilized in air using 2-Mrad irradiation, and the Centrax, which was gamma-sterilized in nitrogen using 3-Mrad irradiation. To image the inner head in vivo, we used high-pressure X-ray photography; we measured linear wear of the polyethylene with software using Martell Method 1.

RESULTS

Comparing mean annual linear wear between the OA and ONFH groups, using IBC prostheses in both groups, there was a significant difference (0.213 mm vs. 0.096 mm, respectively; P = 0.0177). There was a significant difference between the Centrax and IBC prostheses in OA patients in terms of linear wear (0.04 mm vs. 0.213 mm; P = 0.0181).

CONCLUSION

The linear wear of polyethylene in BHA implants can be affected by the material used to manufacture the bipolar cup. Such implants should only be used for appropriate indications.

Clinical results of hemiarthroplasty using new bipolar cups for stage 3 or lower osteonecrosis of the femoral head: a retrospective study

PURPOSE

The aim of this study was to evaluate clinical and radiographic findings of stage 3 or lower osteonecrosis of the femoral head (ONFH) with intact acetabular cartilage in patients treated with bipolar hemiarthroplasty (BHA).

METHODS

A total of 79 hips that underwent BHA for ONFH were included in this study. The average observation period was 7.6 years. Clinical results were evaluated using the Harris hip score. We performed radiographic analysis to assess the migration of the outer cup, the permanent image around the outer cup, and loosening of the stem.

RESULTS

The total Harris hip score improved from 50 points before surgery to 92 points at final follow-up, while pain improved from 14 points to 36 points. Flexion improved from 94° to 120° and abduction from 27° to 37°. One patient on dialysis showed progress in terms of inward migration, and revision surgery was performed on the patient 14 years after the original surgery.

CONCLUSIONS

Midterm performance of BHA for stage 3 or lower ONFH at our hospital was good.

Enhancing the effects of exfoliated carbon nanofibers using bone morphogenetic protein in a rat spinal fusion model

Exfoliated carbon nanofibers (ExCNFs) are expected to serve as excellent scaffolds for promoting and guiding bone-tissue regeneration. We aimed to enhance the effects of ExCNFs using bone morphogenetic proteins (BMPs) and examined their feasibility and safety in clinical applications using a rat spinal fusion model. Group I (n = 15) animals were implanted with the control carrier; Group II (n = 16) animals were implanted with carrier containing 1 μg ExCNFs; Group III (n = 16) animals were implanted with carrier containing 1 μg recombinant human (rh) BMP-2; and Group IV (n = 17) animals were implanted with carrier containing 1 μg rhBMP-2 and 1 μg ExCNFs. The rats were euthanized after 4 or 8 weeks and their spines were explanted and assessed by manual palpation, radiographs, and high-resolution microcomputerized tomography (micro-CT); the spines were also subjected to histological analysis. The fusion rates in Group IV (25.0%: 4-week, 45.5%: 8-week) were considerably higher than in Groups I (0%: 4-week, 0%: 8-week), II (0%: 4-week, 15.0%: 8-week), and III (16.7%: 4-week, 30.0%: 8-week). These results demonstrated the enhancement of ExCNF bone fusion effects by BMP in a rat spinal fusion model. Our results suggest that the enhancement of ExCNFs effects by BMP makes this combination a possible attractive therapy for spinal fusion surgeries. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2892-2900, 2018.