PNI is useful for predicting the prognosis of patients with soft tissue sarcoma: A retrospective study.

BACKGROUND: It is known that preoperative Prognostic Nutritional Index (PNI) is useful in predicting prognosis in gastrointestinal diseases and that preoperative improvement of nutritional status improves prognosis. However, there have been few large-scale reports examining the prognostic value of PNI in soft tissue sarcomas. Therefore, the aim of this study is to investigate whether the PNI can be useful for predicting overall survival in soft tissue sarcoma. METHODS: Between January 2006 and March 2022 at our hospital, 111 patients with pathologically diagnosed soft tissue sarcoma were included, retrospectively. Several nutritional or inflammatory biomarkers such as PNI were calculated from the pretreatment blood sample results. The patients were classified into two groups (low and high groups) based on the median value of each parameter. Overall survival was analyzed by the Kaplan‒Meier method and log-rank test. Univariate and multivariate analyses using the Cox proportional hazards model were used to investigate prognostic factors for overall survival. RESULTS: The median overall survival was 24.3 months (mean 37.3 months), and the high PNI group had a significantly longer overall survival than the low PNI group (p < 0.0001). PNI was the most significant univariate factor for overall survival among other nutritional and inflammatory parameters (HR: 5.64, 95% CI: 2.26-14.12, p = 0.0002). The multivariate proportional hazards model was built using variables with prognostic potential as suggested by previous analysis with respect to patient characteristics and PNI. As potential confounding factors, we included PNI, stage, age, and tumor location. PNI was also an independent prognostic factor in multivariate analysis (HR: 7.02, CI: 2.52-19.40, p = 0.0002). CONCLUSION: PNI is a useful prognostic factor among various parameters for overall survival in patients with soft tissue sarcoma.

Multivariate linear-mixed analysis of changes in anterior inferior iliac spine impingement incidence with posterior pelvic tilt: a computer simulation study.

It is well known that increased posterior tilt of the pelvis is an effective strategy for avoiding impingement of the femur with the pelvis during movement. Daily repetitive collisions become mechanical loads, and the more frequently they occur, the more tissue damage and pain they cause. Therefore, reducing the rate of occurrence of impingement is important to avoid aggravation of symptoms. This study aimed to evaluate the effects of changes in posterior pelvic tilt on the risk of impingement between the femur and the anterior inferior iliac spine (AIIS)/subspine in various functional postures. Patients with femoroacetabular impingement syndrome (FAIS) who were candidates for hip arthroscopic osteochondroplasty between October 2013 and June 2020 were included. A three-dimensional reconstructed model was used to simulate the incidence of impingement at 12 hip positions required for activities of daily living. We predicted value of the spatial incidence of impingement assumed that hip motion should exceed 130/30 degrees without impingement. Impingement was measured at three pelvic positions: an anterior tilt of 10°, in the functional pelvic plane and a posterior tilt of 10°. Multivariate linear-mixed models were used to assess the effect of covariate-adjusted posterior pelvic tilt on the impingement incidence in the AIIS region. AIIS type, center-edge angle, acetabular version and femoral version were used as covariates. The impingement rates and locations of the three pelvic tilt postures were assessed. Seventy-eight patients (60 males and 18 females; average age, 46 ± 15.1 years) with FAIS were analyzed. A multivariate linear-mixed model revealed a coefficient of -0.8% (95% confidence interval -0.9 to -0.7%; P < 0.001) for posterior pelvic tilt. Thus, posterior pelvic tilt affects AIIS impingement incidence. After adjusting for anatomical effects, the posterior pelvic tilt should be addressed to avoid impingement.

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.

Evaluation of the Postoperative Risk of Deep Tissue Injury to the Lower Extremities Following Surgery in the Lithotomy Position.

Background The aim of this study was to determine the incidence of deep tissue injury (DTI) and potential risk factors after surgery in the lithotomy position. Methods All patients who underwent surgery in the lithotomy position under general anesthesia at a single center between January 2017 and December 2021 were retrospectively evaluated. The medical records of these patients were reviewed, and patient demographic and clinical characteristics, surgical data, and occurrence of DTI were recorded. Results During the study period, 5146 patients, 2055 (39.9%) males and 3091 (60.1%) females, with a mean age of 57.3 ± 17.4 years, underwent surgery in the lithotomy position. Seven (0.14%) patients developed DTI on their calf following surgery. All presented with severe pain and swelling, requiring prolonged hospital stay. Multivariate analysis showed that male sex (odds ratio (OR): 11.43; 95% confidence interval (CI): 1.15-113.34, p = 0.037), higher BMI (OR: 1.32; 95% CI: 1.17-1.50, p = 0.0001), and longer operation time (OR: 1.01; 95% CI: 1.004-1.014, p = 0.0002) were independent risk factors for postoperative DTI. Optimal cut-off values for BMI and operation time were 23.5 kg/m2 (sensitivity = 100%; specificity = 64%) and 285 minutes (sensitivity = 100%; specificity = 90%), respectively. Conclusion Factors significantly associated with DTI include male sex, higher BMI, and prolonged operation time.

Physical Therapy May Not Be Successful for Patients With Cam-Type Femoroacetabular Impingement Syndrome and May Result in Insufficient Hip Range of Motion When Femoral Anteversion Is Less Than 16° and α-Angle Is Greater Than 65°.

PURPOSE: To identify factors associated with insufficient range of motion (ROM) improvement after the posterior pelvic tilt change in cam-type femoroacetabular impingement syndrome. METHODS: Preoperative computed tomography images from 71 consecutive patients with femoroacetabular impingement syndrome treated with arthroscopic cam resection were evaluated. Using a dynamic computer simulation program, 3-dimensional models with a 10° posterior pelvic tilt from the supine functional pelvic plane (baseline) were created by computed tomography models. Patients were divided into 2 groups: those who experienced >10° (effective group) and ≤10° (ineffective group) improvements in internal rotation at 90° flexion after a 10° posterior pelvic tilt. Demographic characteristics; preoperative range of internal rotation at 90° flexion; and radiographic parameters, including Tönnis grade, lateral center-edge angle, acetabular roof obliquity angle, central acetabular anteversion, cranial acetabular anteversion, femoral anteversion, and α angle, were compared in the 2 groups. Univariate and multivariable logistic regression analyses were performed to evaluate factors associated with insufficient ROM improvement following a 10° posterior pelvic tilt. RESULTS: The 71 patients included 58 men and 13 women, of mean age 41.4 ± 14.6 years. Posterior pelvic tilt was effective in 13 hips and ineffective in 58. Univariate analysis showed that preoperative range of internal rotation at 90°flexion, femoral anteversion, and α angle differed significantly in the 2 groups. Multivariable analysis showed that femoral anteversion <16° (odds ratio 7.4; 95% confidence interval 1.6-35; P = .012) and α angle >65° (odds ratio 6.7; 95% confidence interval 1.2-37; P = .027) were significant factors associated with insufficient ROM improvement after posterior pelvic tilt. CONCLUSIONS: Physical therapy may not be successful for patients with cam-type femoroacetabular impingement syndrome and may result in insufficient hip ROM when femoral anteversion is less than 16° and α-angle is greater than 65°. CLINICAL RELEVANCE: Patients with a prominent cam-type deformity and lower anterior femoral anteversion are at high risk of clinical failure following improvement in pelvic mobility by conservative treatment alone and are likely to benefit from surgery for cam deformity.

Shelf acetabuloplasty may inhibit range of motion: A computer simulation analysis.

Shelf acetabuloplasty has been performed in patients with developmental dysplasia of the hip (DDH); however, the appropriate position of the shelf has not been determined, particularly with respect to avoiding range of motion (ROM) loss. The aim of this study was to investigate the frequency of ROM inhibition and the influence of 3D position of the shelf following actual shelf acetabuloplasty and virtual surgery using computer simulation analysis. Computed tomography data from 15 patients with DDH who underwent shelf acetabuloplasty were collected between August 2019 and February 2022. The three-dimensional models of a hip joint were constructed using Zed Hip®. Maximal internal rotation (MIR) at 45° and 90° flexion was measured in each patient. The frequency and position of ROM inhibition was determined in a real postoperative model virtually. In addition, a second analysis using virtual acetabuloplasty was performed. Upon placing the shelf, three patterns were provided for the following four parameters: height, coronal inclination, center-edge angle (CEA), and anteroposterior position. The predictors for ROM inhibition were analyzed using a logistic regression model. In the actual postoperative model, a limitation of MIR at 90° and 45° of flexion occurred in 60% and 66.7% of patients, respectively. A higher CEA and anterior position are major factors limiting MIR. The analysis of the virtual shelf acetabuloplasty model revealed that anterior position and CEA were significant factors causing ROM inhibition. As for clinical significance, the results of the current study indicated the optimal location of the shelf to avoid iatrogenic impingement after shelf acetabuloplasty.

Safe Ultrasonography-Assisted Knee Posterior Transseptal Portal Creation Technique.

Knee arthroscopy is a minimally invasive surgical technique that allows surgeons to diagnose and treat various knee conditions using much smaller incisions than open surgery. However, it is difficult to fully visualize the posterior compartment of the knee joint using the usual anterior portal approach because of blind spots. The transseptal portal technique enables surgeons to visualize the surgical field and access instruments in the posterior compartment of the knee during arthroscopic surgery. However, creation of the posterior transseptal portal increases the risk of neurovascular injury. Particular attention should be paid to avoid damaging the saphenous nerve, common peroneal nerve, popliteal artery, and tibial nerve. Here, we describe an ultrasonography-guided surgical method for creating the posterior transseptal portal by confirming the surrounding anatomy.

Bevacizumab promotes tenogenic differentiation and maturation of rat tendon-derived cells in vitro.

Previous work suggested that tenogenic differentiation of tendon stem/progenitor cells (TSPCs) was suppressed by upregulated expression of the angiogenic marker vascular endothelial growth factor (VEGF). The purpose of this study was to test the hypothesis that anti-VEGF antibody, bevacizumab, promotes in vitro tenogenic differentiation and maturation of two distinct types of TSPCs, tendon proper-derived cells (TDCs), and paratenon-derived cells (PDCs) originating from rat Achilles tendon. TDCs and PDCs were isolated from the tendon proper and the paratenon of rat Achilles tendons. TDCs and PDCs were cultured for 3 days on plates with or without VEGF. TDCs and PDCs were also cultured in collagen gel matrix, and the blocking effect of VEGF was examined by the addition of 100 ng/mL of bevacizumab. Effects of bevacizumab on tenogenic differentiation were assessed using real-time PCR, immunofluorescent staining, and western blotting. VEGF significantly attenuated expression of the Tnmd gene in both PDCs and TDCs (P<0.05). Expressions of the Scx, Tnmd, and Col1a1 genes were significantly upregulated by the addition of bevacizumab (P<0.05). Immunofluorescent staining showed that the percentage of tenomodulin-positive PDCs and TDCs was significantly higher with bevacizumab treatment than in control cultures (P<0.05). Western blotting showed that bevacizumab suppressed pVEGFR-2 protein expression in both PDCs and TDCs. Bevacizumab promoted the in vitro tenogenic differentiation and maturation of two distinct TSPCs derived from rat Achilles tendon. Since the previous studies demonstrated that TSPCs have a potential to contribute to tendon repair, attenuating VEGF levels in TSPCs by administration of bevacizumab is a novel candidate therapeutic option for promoting tendon repair.

Application of Intraoperative CT-Ultrasound Fusion Imaging in Hip Endoscopy for Treatment of Iatrogenic Impingement Due to PLLA Screw: A Novel Surgical Technique.

Ultrasound-assisted surgery is becoming an established tool in the medical field. The addition of imagery to ultrasound-assisted surgery may enable one to perform a procedure in a safer and more accurate manner. This can be achieved through fusion imaging (fusion), a technology that synchronizes MRI or CT images with ultrasound images. We describe intraoperative CT-ultrasound fusion-guided (or -assisted) hip endoscopy for the removal of an impinging poly L-lactic acid screw, which was difficult to identify on fluoroscopy during surgery. The fusion technology enables merging two advantages of ultrasound: the real-time guidance capabilities and CT or MRI and the bird's eye view that makes minimally invasive arthroscopic and endoscopic surgery less invasive, precise, and safe.

Tranexamic acid administration for the prevention of periprosthetic joint infection and surgical site infection: a systematic review and meta-analysis.

INTRODUCTION: Tranexamic acid (TXA) has been widely utilized to reduce blood loss and allogeneic transfusions in patients who undergo lower limb arthroplasty. In recent years, there have been several articles reporting the incidence of periprosthetic joint infection (PJI) as a primary outcome of TXA administration, but no meta-analysis has been conducted to date. The present systematic review and meta-analysis evaluated the efficacy of TXA administration in preventing PJI and surgical site infection (SSI). MATERIALS AND METHODS: Pubmed, CINAHL, and the Cochrane Library bibliographic databases were searched for studies published by May 24, 2022, that evaluated the effects of TXA on PJI and SSI. Two researchers screened the identified studies based on the PRISMA flow diagram. The quality of each randomized clinical trial was assessed using Version 2 of the Cochrane risk-of-bias tool for randomized trials (ROB2.0), and the quality of cohort and case-control studies was assessed by risk of bias for nonrandomized studies (ROBANS-I). RESULTS: Of the 2259 articles identified from the database search, 31 were screened and selected. Treatment with TXA significantly reduced the incidence of overall infection, including PJI, SSI, and other infections (OR 0.55; 95% CI 0.49-0.62) (P < 0.00001), and that of PJI alone (OR 0.53; 95% CI 0.47-0.59) (P < 0.00001). TXA reduced the incidence of overall infection in patients who underwent total hip arthroplasty (THA; OR 0.51; 95% CI: 0.35-0.75) (P = 0.0005) and total knee arthroplasty (TKA; OR 0.55; 95% CI: 0.43-0.71) (P < 0.00001). Intravenous administration of TXA reduced the incidence of overall infection (OR 0.59; 95% CI 0.47-0.75) (P < 0.0001), whereas topical administration did not. CONCLUSIONS: Intravenous administration of TXA reduces the incidence of overall infection in patients undergoing both THA and TKA. LEVEL OF EVIDENCE: Level III.

Targeting of Periprosthetic Muscles for the Ultrasonographic Screening of Hip Abnormalities in Hip Resurfacing Arthroplasty Patients.

BACKGROUND: Hip resurfacing arthroplasty (HRA) patients require subsequent annual screening for postoperative complications. Ultrasonography may be useful for this purpose but lacks a screening protocol for hips. The purpose of this study was to evaluate the accuracy of ultrasonography for detecting postoperative complications in HRA patients using a screening protocol that specifically targets periprosthetic muscles. METHODS: We enrolled 45 hips from 40 HRA patients with a mean follow-up period of 8.2 years. MRI and ultrasonography scans were simultaneously conducted at follow-up. The ultrasonography assessments were conducted on the anterior part of the hip that targets iliopsoas, sartorius, rectus femoris, lateral with anterior superior and inferior iliac spine (ASIS and AIIS) as bony landmarks, and the lateral and posterior parts that target fascia tensor, short rotators, and gluteus minimus, medius, and maximus with greater trochanter and ischial tuberosity as bony landmarks. The accuracy of diagnosing postoperative abnormalities and the visibility of periprosthetic muscles were compared between these two modalities. RESULTS: Both MRI and ultrasonography detected an abnormal region in eight cases comprising two infections, two pseudotumors, and four patients with greater trochanteric bursitis. Among these cases, four hips required implant removal. The increase in anterior space, measured as the distance between the iliopsoas and resurfacing head, was a good indicator for the abnormal mass in these four HRA cases. In the assessment of periprosthetic muscles, MRI showed a much lower visibility than ultrasonography in the iliopsoas (6.7% vs. 100%), gluteus minimus (6.7% vs. 88.9%), and short rotators (8.8% vs. 71.4%) due to implant halation. CONCLUSIONS: By targeting periprosthetic muscles, ultrasonography can detect postoperative complications as effectively as MRI assessments in HRA patients. Ultrasonography has superior visibility in the periprosthetic muscles of HRA patients, indicating its utility for the screening of small legions in these cases which may not be visible by MRI.

Monitoring of blood biochemical markers for periprosthetic joint infection using ensemble machine learning and UMAP embedding.

INTRODUCTION: Periprosthetic joint infection (PJI) is a serious complication after total joint arthroplasty. It is important to accurately identify PJI and monitor postoperative blood biochemical marker changes for the appropriate treatment strategy. In this study, we aimed to monitor the postoperative blood biochemical characteristics of PJI by contrasting with non-PJI joint replacement cases to understand how the characteristics change postoperatively. MATERIALS AND METHODS: A total of 144 cases (52 of PJI and 92 of non-PJI) were reviewed retrospectively and split into development and validation cohorts. After exclusion of 11 cases, a total of 133 (PJI: 50, non-PJI: 83) cases were enrolled finally. An RF classifier was developed to discriminate between PJI and non-PJI cases based on 18 preoperative blood biochemical tests. We evaluated the similarity/dissimilarity between cases based on the RF model and embedded the cases in a two-dimensional space by Uniform Manifold Approximation and Projection (UMAP). The RF model developed based on preoperative data was also applied to the same 18 blood biochemical tests at 3, 6, and 12 months after surgery to analyze postoperative pathological changes in PJI and non-PJI. A Markov chain model was applied to calculate the transition probabilities between the two clusters after surgery. RESULTS: PJI and non-PJI were discriminated with the RF classifier with the area under the receiver operating characteristic curve of 0.778. C-reactive protein, total protein, and blood urea nitrogen were identified as the important factors that discriminates between PJI and non-PJI patients. Two clusters corresponding to the high- and low-risk populations of PJI were identified in the UMAP embedding. The high-risk cluster, which included a high proportion of PJI patients, was characterized by higher CRP and lower hemoglobin. The frequency of postoperative recurrence to the high-risk cluster was higher in PJI than in non-PJI. CONCLUSIONS: Although there was overlap between PJI and non-PJI, we were able to identify subgroups of PJI in the UMAP embedding. The machine-learning-based analytical approach is promising in consecutive monitoring of diseases such as PJI with a low incidence and long-term course.

A rare case of intra-articular synovial sarcoma of the hip joint: a case report with intra-articular findings via hip arthroscopy.

Although synovial sarcoma is a relatively common soft tissue sarcoma, primary intra-articular cases are extremely rare. Herein, we report a case of primary intra-articular synovial sarcoma arising from the hip joint, that was initially treated with hip arthroscopy. A 42-year-old male presented with a history of pain in the left hip for 7 years. Radiography and magnetic resonance imaging revealed the primary intra-articular lesion and simple excision with an arthroscopy was performed. Histological findings revealed spindle cell proliferation with abundant psammoma bodies. SS18 gene rearrangement was confirmed by fluorescence in situ hybridization, and the tumor was diagnosed as synovial sarcoma. Adjuvant chemotherapy and radiotherapy were performed. Local control without metastasis was achieved 6 months after excision. This is the first case of intra-articular synovial sarcoma of the hip joint excised via hip arthroscopy. When an intra-articular lesion is identified, malignancies such as synovial sarcoma should be included in the differential diagnosis.

Effects of changes in whole-body alignment on ipsilateral knee pain after total hip arthroplasty.

BACKGROUND: Total hip arthroplasty decreases hip pain and often reduces knee pain in patients with hip osteoarthritis. Whole-body alignment may be associated with knee pain, but to our knowledge this relationship has not been previously investigated. The purpose of this study was to investigate the effect of changes in whole-body alignment on ipsilateral knee pain in patients after total hip arthroplasty. METHODS: In total, 94 patients with unilateral hip osteoarthritis who underwent total hip arthroplasty were enrolled in this study. A visual analog scale (VAS) was used to investigate perioperative knee pain. An EOS 2D/3D X-ray system was used to quantify the whole-body alignment of the spine, pelvis, and lower extremities in the standing position. The relationship between perioperative changes in knee pain and whole-body alignment was investigated. RESULTS: Among 61 patients who had preoperative ipsilateral knee pain, pain resolved in 30 (50%) and persisted in 31 (50%) after surgery. In these patients, average ipsilateral knee pain decreased significantly after surgery, from 41 mm to 14 mm on the VAS (P < 0.01). Preoperative knee pain was correlated with femorotibial rotation, and postoperative knee pain was correlated with K-L grade, preoperative knee pain visualized analog scale, and preoperative sagittal vertical axis. Multiple linear regression identified preoperative sagittal vertical axis as significantly associated with residual postoperative ipsilateral knee pain. CONCLUSIONS: Ipsilateral knee pain decreased in half of patients after total hip arthroplasty. Patients with a considerable forward-bent posture may have residual ipsilateral knee pain after total hip arthroplasty.

Effect of Tranilast on the Frequency of Invasive Treatment for Extra-Abdominal Desmoid Fibromatosis.

BACKGROUND: Active surveillance (AS) has been suggested for managing extra-abdominal desmoid fibromatosis (EADF), but a substantial percentage of such patients transitioned to invasive secondary treatments. The anti-keloid medication tranilast is frequently used in Japan but its effectiveness for EADF is not well understood. METHODS: We retrospectively analyzed the medical records of EADF patients treated with tranilast between January 2009 and March 2021. EADF has been reported to shrink spontaneously, so the effects of all drugs must be compared with AS. To assess the effect of tranilast, we compared the clinical courses of patients receiving tranilast with those managed by AS (as identified in a systematic review). A systematic review of AS outcomes was conducted on July 22, 2021, in accordance with PRISMA guidelines. The primary endpoint was rate of conversion to secondary treatment. Secondary endpoints were progression-free survival, objective response rate (ORR), disease control rate (DCR), and adverse events. The rates of conversion to secondary treatment, ORRs, and DCRs were compared between the two groups by using the Fisher exact test. RESULTS: Eighteen patients who received tranilast as initial treatment for EADF were included. Two patients (11.1%) underwent surgical resection for treatment of tumor growth and persistent pain. The rate of conversion to secondary treatment was significantly lower for tranilast than for a pure AS approach (40.1%; p = 0.01). ORR and DCR did not differ between groups. CONCLUSIONS: Tranilast was better than AS for initial management of EADF.

Effect of implant composition on periprosthetic bone mineral density after total hip arthroplasty.

BACKGROUND: The severity of bone mineral density (BMD) loss after total hip arthroplasty (THA) depends on both implant- and patient-related factors. While implant fixation type is an important factor, but few studies have considered the effect of material composition on the same implant fixation type. In particular, differences in mechanical stiffness due to material composition are of great interest. Here, we compared changes in periprosthetic BMD after THA using proximal fixation concept stems comprising different titanium alloys, i.e., ß titanium alloys stem and α + ß titanium alloys stem. METHODS: This retrospective cohort included 122 patients (ß titanium alloys stem, 61 cases; α + ß titanium alloys stem, 61 cases) who underwent primary THA between January 2009 and December 2019. The primary outcome was the change in periprosthetic BMD from base line. Age, body mass index, diagnosis, stem size, canal flare index, surgical approach, pre-operative lumbar BMD, and pre-operative activity scores were reviewed and changes in periprosthetic BMD between the two groups were compared using analysis of covariance. The secondary outcome was radiographic response after THA. RESULTS: There was significant difference in periprosthetic BMD in zone 6 and 7 at 2 years (p < 0.05) between the two groups. There was no significant difference in other zones. A significant difference in radiographic response was noted only for the Engh classification. CONCLUSION: α + ß titanium alloys stem resulted in a significantly higher rate of BMD loss in zones 6 and 7 compared with the ß titanium alloys stem. These results may be due to differences in mechanical stiffness due to the different titanium alloy composition of the prosthetics.

Clinical utility of minimally invasive posterior internal fixation within the pelvic ring using S2 alar iliac screws for unstable pelvic ring fracture.

INTRODUCTION: Posterior internal fixation for unstable pelvic ring fractures is often associated with complications, including pelvic hemorrhage and gluteal necrosis. Pelvic ring fixation using the S2 alar iliac screw (SAIS) without fixation of the lumbosacral vertebrae may have potential as a novel, minimally invasive technique for treating unstable pelvic ring fractures. The present study compared clinical outcomes in patients who underwent SAIS fixation within the pelvic ring with a historical control group of patients who underwent conventional trans-iliac plate fixation for the treatment of unstable pelvic ring fractures. MATERIALS AND METHODS: Thirty-two patients diagnosed with unstable pelvic fractures with sacral fracture or sacroiliac joint fracture dislocation were retrospectively evaluated. Eight consecutive patients underwent trans-iliac plate fixation from April 2012 to March 2015, and 24 consecutive patients underwent SAIS fixation from April 2015 to February 2020. Rates of soft tissue complications, intraoperative blood loss, and intraoperative blood transfusion volume were compared in these two groups. RESULTS: Mean intraoperative blood loss was significantly lower in patients who underwent SAIS fixation than in those who underwent trans-iliac plate fixation (141.0 ml vs 315.0 ml; P = 0.027), although there were no between-group differences in intraoperative blood transfusion volume (0.0 ml vs 140 ml; P = 0.105), incidence rate of soft tissue complications (4.2% vs 0%; P = 1.000), and operation time (88.5 min vs 93.0 min; P = 0.862). Bone healing was confirmed in all patients who underwent SAIS fixation without dislocation of the fracture site, whereas one patient who underwent trans-iliac plate fixation experienced a dislocation of the fracture site during follow-up (0% vs 12.5%; P = 0.250). CONCLUSIONS: SAIS fixation reduces intraoperative blood loss and ensures bone healing without major complications, including dislocation of the fracture site. SAIS fixation may therefore be an alternative, minimally invasive method of treating unstable pelvic fractures.

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.

Medial meniscus extrusion and stage are related to the size of spontaneous osteonecrosis of the knee in patients who underwent high tibial osteotomy.

PURPOSE: Spontaneous osteonecrosis of the knee (SONK) causes acute atraumatic knee pain, and meniscus tears may be associated with the pathogenesis of SONK. The purpose of this study was to investigate the relationship of the type of meniscus tear and medial meniscus extrusion with SONK on the medial femoral condyle in patients who underwent surgical treatment with high tibial osteotomy due to severe knee pain. METHODS: We enrolled 98 patients with 102 knees who underwent medial opening wedge high tibial osteotomy (OWHTO) under the diagnosis of medial femoral condyle osteonecrosis at our hospital from December 2003 to January 2020. Based on the Koshino classification, cases of SONK were classified as stage 1-4. The relationships of demographic data, X-rays and MRI images, including femorotibial angle (FTA), meniscus tear type, and medial meniscus extrusion (MME), with the stage and volume of SONK were investigated. RESULTS: Ninety-eight patients (29 males and 69 females), with an average age at surgery of 69.2 ± 9.6 years and Body mass index(BMI) of 61.0 ± 17.6 kg/m2. In 102 cases of SONK, 11 knees, 18 knees, 46 knees, and 27 knees were classified as stage 1-4, respectively. The mean SONK volume was 2161.61 µm (range 95.67-7484.68 µm) on preoperative MRI. The preoperative FTA (mean 180.86°, range 172-187°) was not associated with the stage or volume of SONK. Meniscus tears were found in all cases of SONK and consisted of 2 degenerations, 2 horizontal tears, 0 vertical tears, 40 radial tears, 4 complex tears, and 54 medial meniscus posterior root tears (MMPRTs). In addition, 99% (101/102) of knees showed more than 3 mm of meniscus extrusion. Although the meniscus tear type was not associated with SONK stage, there was a high rate of tears that caused disruption of the hoop strain, such as MMPRTs (52.9%) or radial tears (39.2%). MME was significantly related to SONK volume (r = 0.387, p < 0.001). CONCLUSION: All patients with SONK had coexisting meniscus tears, most menisci had medial extrusion, and a positive correlation was observed between MME and SONK volume.

Prevalence and risk factors of preoperative venous thromboembolism in patients with malignant musculoskeletal tumors: an analysis based on D-dimer screening and imaging.

BACKGROUND: Venous thromboembolism (VTE) is a major complication in patients with malignant tumors and orthopedic disorders. Although it is known that patients undergoing surgery for malignant musculoskeletal tumor are at an increased risk of thromboembolic events, only few studies have investigated this risk in detail. Therefore, the aim of this study was to determine the prevalence and risk factors for preoperative VTE in malignant musculoskeletal tumors patients. METHODS: We retrospectively reviewed the medical records of 270 patients who underwent surgical procedures, including biopsy for malignant musculoskeletal tumor, have undergone measurements of preoperative D-dimer levels, and were subsequently screened for VTE by lower extremity venous ultrasonography and/or contrast-enhanced computed tomography scans. Statistical analyses were performed to examine the prevalence and risk factors for VTE. Receiver operating characteristic (ROC) analysis was performed to verify the D-dimer cutoff value for the diagnosis of VTE. RESULTS: Overall, 199 patients (103 with primary soft tissue sarcomas, 38 with primary bone sarcomas, 46 with metastatic tumors, and 12 with hematologic malignancies) were included. D-dimer levels were high in 79 patients; VTE was detected in 19 patients (9.5%). Multivariate analysis indicated that age ≥ 60 years (P = 0.021) and tumor location in the lower limbs (P = 0.048) were independent risk factors for VTE. ROC analysis showed that the D-dimer cutoff value for the diagnosis of VTE was 1.53 µg/mL; the sensitivity and specificity were 89.5% and 79.4%, respectively. CONCLUSIONS: Our study indicated that age and tumor location in the lower limbs were independent risk factors for preoperative VTE in malignant musculoskeletal tumors patients. D-dimer levels were not associated with VTE in the multivariate analysis, likely because they are affected by a wide variety of conditions, such as malignancy and aging. D-dimer is useful for exclusion diagnosis because of its high sensitivity, but patients with high age and tumor location in the lower limbs are a high-risk group and should be considered for imaging evaluation such as ultrasonography regardless of D-dimer levels. TRIAL REGISTRATION: Our study was approved by the institutional review board. The registration number is B200600056 . The registration date was July 13, 2020.