Efficacy of denosumab in joint preservation for patients with giant cell tumour of the bone

BackgroundGiant cell tumour of the bone (GCTB) is an aggressive osteolytic primary tumour. GCTB is rich in osteoclast-like giant cells and contains mononuclear cells that express RANK ligand (RANKL), a key mediator of osteoclast activation. The potential therapeutic effect of denosumab was investigated with special reference to its role in joint preservation.MethodsIn this prospective non-randomised study patients with GCTB received denosumab for 6–11 months preoperatively. Serial radiographs and biopsy and resection tumour specimens were used to monitor response to denosumab.ResultsAll 20 patients experienced pain relief in the first month of treatment. All patients demonstrated a positive radiographic response with improved subchondral and cortical bone which allowed intralesional tumour resection and preservation of the joint and articular surface in 18 cases. Histological examination following denosumab revealed rarely detectable osteoclast-like giant cells. There was an obvious increase in osteoid matrix and woven bone which showed rare RANK staining amongst the mononuclear cells and only focal RANKL positivity. At median 30 months follow-up after resection, local tumour recurrence occurred in three patients.ConclusionDenosumab provides favourable and consistent clinical, radiographic and pathologic responses which facilitates less aggressive surgical treatment, especially joint preservation. However, the local recurrence rate for GCTB following resection does not seem to be affected by denosumab and remains a concern.     

Biomechanical assessment of single LISS versus double-plate osteosynthesis in the AO type 33-C2 fractures: A finite element analysis

ObjectivesIn the present study, we assessed the biomechanical advantage between the single LISS and double-plate used in AO type 33-C2 fractures with the method of finite element analysis, which will help surgeons choose the optimal therapy to the unstable distal femoral fracture.MethodsThe AO type 33-C2 fractures and the models of LISS plate and medial plate was constructed in 3-matic software and UG-NX software respectively. We then assembled the single plate and the double-plate to the fracture model separately to form the fixation models. After meshing the models’ elements, we used the Abaqus software to perform the finite element analysis. Values of peak Von Mises Stress (VMS) on the plate, maximum deformation of the models and the distance changes of the fracture gap were used to capture the mechanical factors in this study.ResultsOur results indicated that the single LISS underwent 1.2 times higher amount of stress than the double-plate (316.0 MPa VS 281.6 MPa). And the medial plate dispersed some stresses (the maximum stress is 47.4 MPa). Single-plate generated 3 times greater bending angle than double-plate (0.6° VS 0.2°). The bending angles of the single and double-fixation-fracture models are 0.9° and 0.3° respectively. The maximum distance changes of the fracture gap in the single-plate model was 2 times higher than that of double-plate model (2.6 mm VS 1.3 mm). In the torsional load analysis, peak VMS of the single and double model was 1.0 MPa and 0.8 MPa respectively. And the bending angle was 0.8° in the single model and 0.4° in the double model.ConclusionsThe double-plate is more effective scenario using in the distal femoral fractures, particular in unstable fractures with joint involvement.     

Surgical treatment based on pedicle screw instrumentation for thoracic or lumbar spinal Langerhans cell histiocytosis complicated with neurologic deficit in children

Background contextSurgical indications and procedures for spinal Langerhans cell histiocytosis (LCH) in children are still controversial. Reports containing large samples of surgically treated patients are few in the currently available literature, and the reported operative procedures were also somewhat obsolete. So, further investigation based on large-sample cases and using improved surgical techniques is beneficial and helpful to refine the treatment strategy.PurposeTo recommend a reasonable treatment strategy for thoracic or lumbar spine LCH in children complicated with neurologic deficit.Study design/settingRetrospective/academic medical center.Patient sampleTwelve children aged from 2 to 16 years old with the diagnosis of thoracic or lumbar spinal LCH accompanied by neurologic deficit received surgical treatment from January 2005 to January 2010.Outcome measuresFrankel scale for neurologic function, fusion of the mass, and recurrence of the lesion.MethodsAll 12 patients presented initially with local pain and progressive neurologic detriment. Neurologic evaluation revealed two patients with Frankel Grade B, eight with Grade C, and two with Grade D. Radiographic features were positive for typical vertebra plana, a space-occupying mass in the spinal canal compressing neural elements, and a spinal canal encroachment rate more than 50%. Posterior instrumentation with pedicle screw combined with anterior corpectomy, decompression, and support bone graft was performed in the first seven patients as a one-stage procedure. In the remaining five patients, posterior pedicle screw fixation, laminectomy for decompression (via excision of the tumor-like mass), and repair of laminae with allograft bone block were performed. The collapsed vertebral body was left untouched. No chemotherapy or radiotherapy was administrated postoperatively in any of the cases.ResultsThe mean follow-up duration was 43.3 months. The mean operation time was 330 minutes with combined procedure and 142 minutes with single posterior approach (p=.000). The average blood loss was 933 mL with combined procedure and 497 mL with single posterior approach (p=.039). Three of seven patients who received combined surgery encountered approach-related complications, that is, one with intercostal neuralgia and two with pleural effusion. No severe neurologic deteriorate, instrumentation failure, or disease recurrence was detected at follow-up. Neurologic function completely recovered in all 12 patients from 2 to 12 weeks after surgery. The anterior bone graft fused and shaped well in all seven patients, and allograft bone block for lamina repair also achieved complete fusion in the remaining five patients. The internal fixator was removed at 3 to 5 years (average 4.1 years) after initial operation in six patients. No deformity, including scoliosis and kyphosis, has been identified during follow-up period in both procedures.ConclusionsFor spinal LCH patients, neurologic deficit is a main indication for operative treatment to prevent permanent and serious consequences. Surgery provides an opportunity for rapid recovery of neurologic function. Both combined and single-stage posterior approaches based on pedicle screw instrumentation techniques are similarly effective in relieving neurologic compression. However, single-stage posterior approach is more favorable with less complications, and preserving involved vertebral body is not a latent hazard of recurrence.     

Regression models to predict hip joint centers in pathological hip population

The purpose was to investigate the validity of Harrington's and Davis's hip joint center (HJC) regression equations on a population affected by a hip deformity, (i.e., femoroacetabular impingement). Sixty-seven participants (21 healthy controls, 46 with a cam-type deformity) underwent pelvic CT imaging. Relevant bony landmarks and geometric HJCs were digitized from the images, and skin thickness was measured for the anterior and posterior superior iliac spines. Non-parametric statistical and Bland-Altman tests analyzed differences between the predicted HJC (from regression equations) and the actual HJC (from CT images). The error from Davis's model (25.0 ± 6.7 mm) was larger than Harrington's (12.3 ± 5.9 mm, p < 0.001). There were no differences between groups, thus, studies on femoroacetabular impingement can implement conventional regression models. Measured skin thickness was 9.7 ± 7.0 mm and 19.6 ± 10.9 mm for the anterior and posterior bony landmarks, respectively, and correlated with body mass index. Skin thickness estimates can be considered to reduce the systematic error introduced by surface markers. New adult-specific regression equations were developed from the CT dataset, with the hypothesis that they could provide better estimates when tuned to a larger adult-specific dataset. The linear models were validated on external datasets and using leave-one-out cross-validation techniques; Prediction errors were comparable to those of Harrington's model, despite the adult-specific population and the larger sample size, thus, prediction accuracy obtained from these parameters could not be improved.     

Titanium Alloy Gamma Nail versus Biodegradable Magnesium Alloy Bionic Gamma Nail for Treating Intertrochanteric Fractures: A Finite Element Analysis

ObjectiveTo using finite element analysis to investigate the effects of the traditional titanium alloy Gamma nail and a biodegradable magnesium alloy bionic Gamma nail for treating intertrochanteric fractures.MethodsComputed tomography images of an adult male volunteer of appropriate age and in good physical condition were used to establish a three‐dimensional model of the proximal femur. Then, a model of a type 31A1 intertrochanteric fracture of the proximal femur was established, and the traditional titanium alloy Gamma nails and biodegradable magnesium alloy bionic Gamma nails were used for fixation, respectively. The von Mises stress, the maximum principal stress, and the minimum principal stress were calculated to evaluate the effect of bone ingrowth on stress distribution of the proximal femur after fixation.ResultsIn the intact model, the maximum stress was 5.8 MPa, the minimum stress was −11.7 MPa, and the von Mises stress was 11.4 MPa. The maximum principal stress distribution of the cancellous bone in the intact model appears in a position consistent with the growth direction of the principal and secondary tensile zones. After traditional Gamma nail healing, the maximum stress was 32 MPa, the minimum stress was −23.5 MPa, and the von Mises stress was 31.3 MPa. The stress concentration was quite obvious compared with the intact model. It was assumed that the nail would biodegrade completely within 12 months postoperatively. The maximum stress was 18.7 MPa, the minimum stress was −12.6 MPa, and the von Mises stress was 14.0 MPa. For the minimum principal stress, the region of minimum stress value less than −10 MPa was significantly improved compared with the traditional titanium alloy Gamma nail models. Meanwhile, the stress distribution of the bionic Gamma nail model in the proximal femur was closer to that of the intact bone, which significantly reduced the stress concentration of the implant.ConclusionThe biodegradable magnesium alloy bionic Gamma nail implant can improve the stress distribution of fractured bone close to that of intact bone while reducing the risk of postoperative complications associated with traditional internal fixation techniques, and it has promising clinical value in the future.     

The position of the centre of the femoral head relative to the midline of the pelvis: A consistent landmark in total knee replacement surgery

BackgroundFemoro-tibial malalignment in excess of 3° is a recognised contributor of early mechanical failure in total knee replacement (TKR). Knowledge of the location of the centre of the femoral head is a pre-requisite to identification of the mechanical axis of the femur and can facilitate optimal component orientation. We investigated variation in the location of the centre of the femoral head relative to the midline of the pelvis.MethodsWe analysed the pelvic radiographs of 150 patients with unilateral total hip replacements. The perpendicular distance from the centre of the femoral head of the non-operated hip to the centre of pubic symphysis was measured.ResultsThe mean distance from the centre of the femoral head to the pubic symphysis was 89.2 mm (standard deviation, 5.7 mm). Patient height strongly correlated with this distance (r = 0.53, p < 0.01), as did the diameter of the femoral head (r = 0.59, p < 0.01). The latter was significantly larger in men than in women (50.9 mm vs. 44.5 mm, p < 0.01).ConclusionThe results demonstrate that the position of the centre of the femoral head has very little variability, irrespective of patient age or body-mass index. If the gender-specific mean femoral head to midline distance is used to estimate the location of the femoral head centre, a line from this point to the centre of the femoral condyles will deviate from the true mechanical axis by no more than 1.5°, in 98% of cases.     

C1 dome-like laminotomy and posterior C1–C2 polyaxial screw-rod fixation for a patient with cervical myelopathy due to a retro-odontoid pseudotumor

A 49-year-old man presented with progressive cervical myelopathy caused by a retro-odontoid mass, with associated developmental canal stenosis at C1, and C1–C2 instability. Surgery was scheduled for a dome-like laminotomy at C1, posterior C1–C2 fixation using C1 lateral mass screws and C2 pedicle screws, and structural bone grafting between C1 and C2. Prior to surgery, we produced a 3-dimensional full-scale model of the patient’s cervical spine and performed a simulation of the scheduled surgery. Through the simulation, we accurately evaluated the laminotomy sites and the screw insertion points. During the actual surgery, all procedures were successful. After surgery, the patient’s neurological deficits markedly improved. Successful C1–C2 fusion, adequate decompression of the spinal cord, and spontaneous regression of the retro-odontoid mass were achieved by this procedure without any apparent restriction in neck movement.     

外侧锁定接骨板治疗股骨远端骨折术后翻修的相关影响因素

目的：分析外侧锁定接骨板治疗股骨远端骨折术后因骨折不愈合或内固定断裂需要进行翻修手术的相关因素。方法：回顾性分析了北京大学第三医院2005年3月至2019年3月诊治的股骨远端骨折患者的临床资料,共有130例患者纳入该研究,翻修组12例,未翻修组118例。利用SPSS 17.0软件对患者的一般情况[性别、年龄、体重指数(body mass index, BMI)、合并基础疾病、吸烟史]、损伤相关因素(受伤原因、开放或闭合性损伤、骨折AO/OTA分型、骨折累及区域分布)、手术相关因素(手术时间、复位质量、是否出现术后感染)及内固定结构等临床资料进行单因素比较及Logistic回归分析。结果：130例纳入该研究的患者中12例进行了翻修手术,翻修率为9.2%。单因素分析发现年龄、BMI、骨折AO/OTA分型、骨折累及区域、手术时间、复位质量、接骨板长度/骨折区长度及髁螺钉上方的接骨板长度/骨折区长度在翻修组和未翻修组的差异具有统计学意义(P<0.05);Logistic回归分析发现骨折AO/OTA分型中A3型骨折、骨折累及髁上区域、手术时间、复位质量和髁螺钉上方的接骨板长度/骨折区长度是...     

新型冠状病毒肺炎疫情期间骨科急症处理原则的专家共识

自2019年12月以来,湖北省武汉市部分医院相继收治多个有华南海鲜市场暴露史的不明原因肺炎病例[1]。患者症状多为发热、乏力、干咳并逐渐出现呼吸困难,部分重症患者出现了急性呼吸窘迫综合征或脓毒症休克、甚至病死。2020年1月7日,我国研究人员首次从患者标本中检测出一种新型冠状病毒[2]。2020年1月20日,中华人民共和国国家卫生健康委员会发布2020年1号公告,将新型冠状病毒感染的肺炎纳入乙类传染病,并按照甲类传染病进行防疫、控制[3]。世界卫生组织将新型冠状病毒肺炎命名为"COVID-19"[4]。     

A method for assessing joint line shift post knee arthroplasty considering the preoperative joint space

BackgroundAccurate comparison of outcomes regarding various surgical options in knee arthroplasty can benefit from an improved method for joint line analysis that takes into account the preoperative joint space.MethodsThis article describes a new preoperative-based registration method that measures changes in the joint line by overlaying the 3D models of the bones with implants using preoperative CT along with preoperative and postoperative biplanar radiography. The method was tested on six cadaveric specimens for measuring alteration to the medial and lateral joint lines in extension and flexion.ResultsThe joint line shift, when measured using the new method, was in the range of − 0.2 to 1.3 mm on average (SD = 1.3 to 3.8 mm, for medial and lateral, in flexion and extension positions). This was significantly different (p ≤ 0.01) from the results of a previous postoperative-based registration method which did not account for the cartilage thickness in calculating alterations of the joint line (mean = 3.9 to 6.8 mm, SD = 1.2 to 4.3 mm).ConclusionThese results further highlight the importance of considering the preoperative joint space in analyzing the joint line, and demonstrate the utility of the newly introduced method for accurate assessment of changes in the joint line after arthroplasty.Clinical relevanceThe introduced method provides accurate means for investigating joint line alterations in relation to different surgical techniques and the subsequent biomechanical effects after knee arthroplasty