标杆型3D打印导板在寰枢椎脱位治疗中的应用疗效及准确性研究

背景:寰枢椎解剖结构复杂,寰枢椎后方毗邻生命中枢延髓,徒手进行寰枢椎椎弓根置钉有较大难度,一旦出现置钉偏差即有可能造成椎动脉、脊髓、静脉丛及神经根的损伤。目的:探讨标杆型3D打印导板在寰枢椎脱位治疗中的应用疗效及准确性。方法:回顾性分析2017年1月至2019年3月收治的44例寰枢椎脱位患者的临床资料,根据治疗方式不同分为徒手置钉的对照组20例,标杆型3D打印导板辅助置钉的研究组24例。观察两组的手术时间、出血量、透视次数;术后复查CT判断置钉准确率;术前和术后6个月随访时采用日本骨科协会(JOA)颈椎神经功能评分评估患者的颈部神经功能,采用视觉模拟评分法(visual analogue scale,VAS)评估患者的枕颈部疼痛情况。结果:两组术中出血量及手术时间比较,差异无统计学意义(P>0.05),但研究组术中透视次数相比对照组少(P<0.05);研究组术后6个月的颈部神经功能及VAS评分明显优于对照组(P<0.05);研究组置钉准确率更高(P<0.05)。结论:借助标杆型3D打印导板可有效减少寰枢椎脱位治疗中的透视次数,提高椎弓根螺钉的置钉准确率,促进术后颈部神经功能恢复,降低枕颈部疼痛程度,值得临床推广。     

Biofilm Producing Staphylococcus epidermidis (RP62A Strain) Inhibits Osseous Integration Without Osteolysis and Histopathology in a Murine Septic Implant Model

Despite its presence in orthopaedic infections, Staphylococcus epidermidis's ability to directly induce inflammation and bone destruction is unknown. Thus, we compared a clinical strain of methicillin-resistant biofilm-producing S. epidermidis (RP62A) to a highly virulent and osteolytic strain of methicillin-resistant Staphylococcus aureus (USA300) in an established murine implant-associated osteomyelitis model. Bacterial burden was assessed by colony forming units (CFUs), tissue damage was assessed by histology and micro-computed tomography, biofilm was assessed by scanning electron microscopy (SEM), host gene expression was assessed by quantitative polymerase chain reaction, and osseous integration was assessed via biomechanical push-out test. While CFUs were recovered from RP62A-contaminated implants and surrounding tissues after 14 days, the bacterial burden was significantly less than USA300-infected tibiae (p < 0.001). In addition, RP62A failed to produce any of the gross pathologies induced by USA300 (osteolysis, reactive bone formation, Staphylococcus abscess communities, marrow necrosis, and biofilm). However, fibrous tissue was present at the implant-host interface, and rigorous SEM confirmed the rare presence of cocci on RP62A-contaminated implants. Gene expression studies revealed that IL-1β, IL-6, RANKL, and TLR-2 mRNA levels in RP62A-infected bone were increased versus Sterile controls. Ex vivo push-out testing showed that RP62A-infected implants required significantly less force compared with the Sterile group (7.5 ± 3.4 vs. 17.3 ± 4.1 N; p < 0.001), but required 10-fold greater force than USA300-infected implants (0.7 ± 0.3 N; p < 0.001). Taken together, these findings demonstrate that S. epidermidis is a commensal pathogen whose mechanisms to inhibit osseous integration are limited to minimal biofilm formation on the implant, and low-grade inflammation. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:852-860, 2020     

Short-Term Follow-Up of Patellar Component Revision in Patients With Isolated Patellar Component Loosening

BackgroundThe etiology of patellar component loosening can be multifactorial, including component malposition, trauma, infection, and poor implant design. These cases may be managed with isolated patellar component revision or simultaneous patellar component with femoral and/or tibial component revision. Isolated patellar revision in the setting of aseptic loosening historically has had limited success with high rates of repeat revision.MethodsWe performed a retrospective cohort study of 75 cases diagnosed with patellar component loosening that underwent revision. Patients were followed for a minimum of 2 years. Cases were categorized as either isolated patellar (IP) revision or patellar with femoral and/or tibial component (P + O) revisions. Survivorship and re-revision causes were compared between groups. Secondary outcomes included surgical time, estimated blood loss, range of motion, and length of stay.ResultsFifty patients underwent IP revision, and 25 patients had P + O revision. Overall survivorship at the 2-year follow-up interval was 94.6%. Survivorship of IP revision undertaken for aseptic loosening was 94%. Survivorship of P + O revision was 96%. Eight percent of patients required reoperation from the P + O revision group, while 12% of patients in the IP revision group underwent a reoperation. Patients undergoing IP revision had better postoperative range of motion, lower surgical times, lower estimated blood loss, and decreased length of stay.ConclusionIP revision demonstrates excellent survivorship and clinical outcomes comparable to P + O revision. When appropriate, IP revision should be considered as a potential treatment option.Level of EvidenceLevel III, retrospective cohort study.     

Cemented vs Uncemented Femoral Components: A Randomized,Controlled Trial at 10 Years Minimum Follow-Up

BackgroundThe type of total knee arthroplasty (TKA) fixation (cemented or uncemented) is still subject to debate. The aim of this study is to assess the survival rate, clinical outcomes, and radiological results of TKA according to the fixation type.MethodsA total of 130 patients were randomly assigned to either the cement group (cemented femoral and tibial implants) or the hybrid group (cemented tibial implant, uncemented femoral implant). The inclusion criteria were patients between 50 and 90 years old who underwent primary TKA for osteoarthritis between 2004 and 2005 without a history of open knee surgery. Revisions and complications were reported, as well as clinical scores and radiological signs of loosening.ResultsOne hundred eighteen patients had complete data at 10 years of minimum follow-up (59 in each group). The mean age was 72 years old. The mean follow-up was 13 years. The survival rate was 98% at 13 years in both groups (1 aseptic loosening at 2 years in the cement group, 1 septic loosening in the hybrid group). The complication rate in the cement group was 8.5% (n = 5) vs 12.1% (n = 7) in the hybrid group (P = .8). The clinical results were not significantly different. In the cement group, 25% of patients (n = 15) had radiolucent lines at 10 years. In the hybrid group, 33% of patients had bone transparencies, not evolving or symptomatic.ConclusionAt a minimum follow-up of 10 years, there were no significant differences between cemented TKA and hybrid TKA for the survivorship, the complication rate, the clinical scores, or the radiological signs of loosening.Level of EvidenceI.     

Results of Cemented Posterior-Stabilized Total Knee Arthroplasty in Obese Patients With an Average 10-Year Follow-Up

BackgroundObese and morbidly obese patients undergoing primary total knee arthroplasty (TKA) place significant stress at the bone-cement-implant interface over the life of the patient. The purpose of this study is to evaluate results of cemented, posterior-stabilized TKA in obese and morbidly obese patients at an average follow-up of 10 years.MethodsRetrospective study of 181 patients who had a cemented, posterior-stabilized TKA between 2000 and 2013 with body mass index >35 at the time of surgery was conducted. Clinical data and radiographs were evaluated along with survivorship, complications, and revisions. Minimum follow-up was 5 years with an average follow-up of 10 years.ResultsThere were 135 women and 46 men in the study, with mean age of 60.2 years (range 43-80), mean body mass index of 42.0 (range 35.1-66.1), and an average follow-up of 10 years (range 5-18). There were a total of 39 failures (22%) that underwent revision TKA surgery with mean time to revision of 8 years. Failures included 25 (14%) cases of aseptic loosening; 9 (5%) polyethylene wear; 2 (1%) prosthetic joint infection; and 3 additional revisions for instability, pain, and stiffness. There were a total of 11 cases of isolated tibial component loosening and 13 for both tibial and femoral loosening. Survivorship at 15 years with aseptic loosening as the endpoint was 86.7%, and for all causes 79.6% at 15 years.ConclusionAseptic loosening is the leading cause of failure following TKA in obese and morbidly obese patients with decreasing survivorship from 96.1% to 91.2% and 86.7% at 5, 10, and 15 years, respectively.     

Why Do Revision Total Knee Arthroplasties Fail? A Single-Center Review of 1632 Revision Total Knees Comparing Historic and Modern Cohorts

BackgroundUtilization of revision total knee arthroplasty (TKA) has been increasing, and reasons for failure are less understood than those of primary TKA. The purpose of this study is to identify the rates and mechanisms of failure of revision TKA, and compare those between a historic (1986-2005) and modern (2006-2015) cohort.MethodsAll revision TKAs performed at a single institution between 1986 and 2015 were reviewed, with minimum 2-year follow-up. Failure was defined as a second revision surgery in which any component was exchanged. Diagnosis at the time of index and any re-revision procedure was determined.ResultsIn total, 1632 revision TKAs in 1560 patients were reviewed. The average age was 65.1 and the average follow-up was 61.4 months. Overall failure rate was 22.8%, with no significant differences between the historic and modern cohort (25.1% vs 22.0%, P = .19). The leading cause for failure was infection in 38.5% of failures. The next most common causes for failure were aseptic loosening (20.9%) and instability (14.2%). Failure rate among revision TKAs for infection was 33%, with 67.2% failing due to repeat infection. Multivariate analysis found that septic index revision (odds ratio [OR] 1.91, 95% confidence interval [CI] 1.47-2.48), male gender (OR 1.41, 95% CI 1.11-1.78), and age less than 65 (OR 1.56, 95% CI 1.23-1.97) were independent risk factors for failure.ConclusionThere remains a high rate of failure in revision TKA, with infection being the most common reason for failure. Rates and primary reasons for failure have not changed significantly in the past decade.     

寰枢椎椎弓根螺钉固定治疗齿状突骨折并寰枢关节脱位

目的探讨寰枢椎椎弓根螺钉固定在对治疗齿突骨折合并寰枢关节脱位患者的疗效。方法筛选从2006年11月至2012年9月在我院就诊治疗的21例齿突骨折合并寰枢关节脱位患者,且均是本地居民,在手术前对21例患者进行日本骨科协会(JOA)评分标准进行评分,得分8¹4分,平均分(10.6±1.4)分,在治疗出院后随访时再次进行评分并和术前水平对比。结果对21例患者实施寰枢椎椎弓根螺钉固定术,术后患者均完全复位,且无神经根、脊髓损伤情况,在术后10个月时对患者进行随访调查并复查X线,发现固定情况良好,无松动等情况发生,同时JOA评分1414分,平均分(10.6±1.4)分,在治疗出院后随访时再次进行评分并和术前水平对比。结果对21例患者实施寰枢椎椎弓根螺钉固定术,术后患者均完全复位,且无神经根、脊髓损伤情况,在术后10个月时对患者进行随访调查并复查X线,发现固定情况良好,无松动等情况发生,同时JOA评分14¹7分,平均得分为(15.5±1.2)分。和患者入院时的评分结果对比提升明显(P<0.05),有统计学意义。结论寰枢椎椎弓根螺钉固定术很好的解决了齿突骨折合并寰枢关节脱位患者的困扰,能长期维持颅颈区稳定性,具有一定创新性。     

Establishing a central zone in scaphoid surgery: a computational approach

Purpose

Scaphoid fractures are commonly fixed with headless cannulated screws positioned centrally in the scaphoid. Judgement of central placement of the screw may be difficult. We generated a central zone using computer analysis of 3D reconstructions of computed tomography (CT) images. As long as the screw axis is completely contained within this central zone, the screw would be considered as centrally placed.

Methods

Thirty cases of 3D CT reconstructions of normal scaphoids in a computerised operation planning and simulation system (Vxwork software) were obtained. The central zone was established after some distance shrinkage of the original scaphoid surface reconstruction model using the function “erode” in the software. The shape of the central zone was evaluated, and the width of the central zone in the proximal pole, waist portion and distal pole was measured. We also established the long axis of the scaphoid to see whether it stays in the central zone.

Results

All central zones could be divided into distal, waist and proximal portions according to the corresponding irregular shape of the scaphoid. As the geometry of the central zone was so irregular and its width very narrow, it was possible to completely contain the screw axis either in the proximal portion alone, waist alone or distal central zone alone.

Conclusions

Establishing the central zone of scaphoid 3D CT images provided a baseline for discussion of central placement of a scaphoid screw. The geometry of the scaphoid central zone determined that the screw could hardly be inserted through entire scaphoid central area during surgery.     

High Failure Rates of the Spectron EF Stem at a Minimum of 10 Year's Follow-up

We prospectively followed 112 hips, undergoing THA with a Spectron EF stem. At mean follow-up of 11.2 years, 21 patients had died. We obtained radiological follow-up in 99% and clinical follow-up in 100% of the surviving 91 hips. Fifty-four percent demonstrated osteolysis in at least one Gruen zone. Twenty-two hips required revision for all causes, with a further five stems radiologically loose. With endpoint being stem revision for aseptic loosening or radiological failure, survivorship at 11 years was 0.783. We believe the addition of a rougher surface finish has contributed to the high levels of osteolysis and stem failure seen with the Spectron EF.     

界膜与人工髋关节松动的相关性分析

目的：通过对松动假体界膜的研究分析人工髋关节松动的原因。方法：通过对28例人工髋关节翻修术中松动假体周围界膜组织进行肉眼外观及扫描电镜对表面超微结构的观察来分析人工髋关节无菌性松动与界膜之间的相关联系。结果：所有本组28例松动假体周围均充填有薄厚大小不一的界膜组织,多数颜色为暗红色,约1／3的界膜部分有黑色;界膜较厚处质韧类似瘢痕结缔组织,薄处似纤维薄膜。扫描电镜观察可以见到大量的粗细不等排列无序的胶原纤维组织和大小不一分布不均的异物颗粒和骨碎屑,胶原纤维内有成纤维细胞分布。结论：人工假体与骨骼形状不完全匹配,空隙的产生导致纤维瘢痕组织（界膜）充填,磨损微粒沿空隙扩散至界膜刺激界膜释放炎性细胞因子导致骨溶解而出现假体松动,松动后的假体与骨髓腔空隙加大导致更多界膜组织充填、释放溶骨性细胞因子而形成恶性循环。