Nontraumatic superior dislocation of the patella

A case of superior patellar dislocation is described. The dislocation was sustained without apparent trauma. Closed reduction was accomplished in the emergency department. No apparent injury to the patellar ligament was sustained.     

Intraosseous Pressure in the Patella in Relation to Simulated Joint Effusion and Knee Position: An Experimental Study in Puppies

Simultaneous pressure measurements were carried out in the patella, juxtaarticular epiphyses and the knee joint cavity of six mongrel puppies. The mean intraosseous pressure in the patella was 12.2 mmHg, range 8-15 mmHg. An increase in intraarticular pressure in turn caused an increase in the intraosseous pressure of the patella and juxtaarticular epiphyses. The pressure increase in the patella was the most pronounced. During extension of the knee joint, a significant rise in intraosseous pressure of the tibial epiphysis and patella was observed, whereas during flexion femoral epiphyseal pressure and patellar pressure increased significantly. The introduction of moderate intraarticular effusion amplified intraosseous pressure responses during flexion of the knee joint. The intraosseous pressure changes during knee movement could not be explained solely by the corresponding changes in intraarticular pressure.

Intraosseous phlebography revealed a venous drainage system largely parallel to the arterial blood supply. The contrast clearance time was decreased during moderate elevation of the intraarticular pressure, suggesting increased bone blood flow of the patella.     

Smooth flexible versus active tapered shaft design using NiTi rotary instruments

AIM: The aim of this study was to evaluate the influence of a smooth flexible versus active tapered shaft design on canal preparation by NiTi rotary techniques. METHODOLOGY: A XMCT-scanner (SkyScan 1072) and developed software (Bergmans et al. 2001) were used to nondestructively analyze the mesial canals of 10 extracted mandibular molars in 3D with a spatial resolution of 30 microm. Specimens (n = 10 per group) were scanned before (PRE) and after (POST) preparation using Lightspeed (smooth flexible) or GT-rotary (active tapered) files. Numerical values for volumes, dentine removal (net) transportation and centring ability were obtained in addition to a visual inspection on canal aberrations. Data were analyzed by Shapiro Wilk test, multiway factorial anova, Tukey-Kramer test, Wilcoxon test and t-test. RESULTS: Results indicated that the active tapered shaft removed significantly more dentine in the middle to apical portion of the root compared to the smooth flexible design. Both groups demonstrated some straightening, but no significant differences were found with respect to instrument types. However, absolute values for net transportation and centering ratio were small and no canal aberrations could be found. CONCLUSIONS: The smooth flexible shaft design did not improve the morphological characteristics of canal preparation by NiTi rotary instruments when compared with the active tapered design. Therefore, system selection should be based upon other criteria.     

Precise 3D skeletal kinematics using fast phase contrast magnetic resonance imaging

PURPOSE: To examine the precision of cine-phase contrast (PC) magnetic resonance imaging (MRI) techniques as applied to the quantification of three-dimensional knee joint kinematics. MATERIALS AND METHODS: The knee joints of eight healthy volunteers were studied using three different dynamic, PC MRI protocols: cine-PC (one average), cine-PC (two averages), and cine-PC with segmented phase encoding (fast-PC). RESULTS: Fast-PC has comparable precision, shorter scan times, and improved subject interexam variability (SIEV) compared to cine-PC (two averages). Further, cine-PC (one average) has low precision and high SIEV, making fast-PC the preferred method of data acquisition. Specifically, the precision of fast-PC MRI in measuring knee joint kinematics ranged from 0.22 degrees -1.16 degrees. CONCLUSION: A cine-PC MRI technique utilizing segmented phase encoding (fast-PC MRI) acquires dynamic data at a faster rate than other PC imaging protocols, without compromising data precision. Being able to acquire precise 3D kinematics with shorter imaging times is critical if we are to use this technique to advance ongoing research in musculoskeletal kinematics.     

Patients with lateral tracking patella have better pain relief following CT-guided tuberosity transfer than patients with unstable patella

In patients with either lateral tracking patella or unstable patella the pathological lateral position of the tuberosity can be corrected by a medial transfer. This study compared the results of subtle CT-guided correction of the tuberosity for objective unstable patella (n=27) with the results for lateral tracking patella (potential instability) as described by Dejour (n=16). Follow-up was 37 months. CT revealed a pathological lateralization of the tibial tuberosity–trochlear groove greater than 15 mm in 41 knees. These patients underwent medialization of the tibial tuberosity up to 10–12 mm lateral from the trochlear groove, and 28 patients underwent a distalization to normalize the Caton index to 1.0–1.2. Results were evaluated using Cox' method. Patients with objective patellar instability were rated as 11% excellent, 52% good, 33% fair, and 4% poor. All patients became stable except one who had a 6° valgus alignment. Although 96% had improved stability, 33% of the patients still had pain. The patients with lateral tracking patella (potential instability) were rated as 37.5% excellent, 44% good, and 19% fair. The lower proportion of pain relief in patients with unstable patella is likely the result of the cartilage damage experienced by these patients following multiple dislocations. Thus the patient with lateral tracking patella without patella dislocations must be differentiated from the one with unstable patella. Their prognosis in pain relief is better.     

记忆合金聚髌器治疗髌骨骨折42例

目的 探讨记忆合金聚髌器治疗髌骨骨折的手术方法及疗效。方法 我科自2003年3月～2006年7月，应用聚髌器治疗髌骨骨折42例。结果 所有病例随诊3～20个月，全部患者髌骨愈合良好，膝关节功能恢复满意。结论 记忆合金聚髌器治疗髌骨骨折具有操作简便，骨折复位良好，固定牢固，便于早期功能锻炼。     

儿童习惯性髌骨脱位的诊治体会

目的探讨儿童习惯性髌骨脱位的诊断和治疗。方法儿童习惯性髌骨脱位患儿21例，全部采用膝关节外侧软组织松解、内侧关节囊紧缩、半侧髌韧带内移或胫骨粗隆内移术等联合手术。结果本组21例患儿，经6个月～3年随访，检查膝关节功能，屈曲膝关节90°，髌骨不再脱位，疗效均较满意。结论采用膝关节外侧软组织松解、内侧关节囊紧缩、半侧髌韧带内移或胫骨粗隆内移术等联合手术治疗儿童习惯性髌骨脱位，疗效确定，且年龄越小，手术效果越好。     

髌骨爪外固定治疗髌骨骨折157例分析

评价髌骨爪治疗髌骨骨折的效果。方法Ｘ线电视下用髌骨爪对髌骨骨折进行复位固定治疗１５７例。平均随访２０ｍｏ对随访结果进行疗效评价。结果髌骨折治疗髌骨骨折，优良率为８４％。结论髌骨爪治疗髌骨骨折，疗效良好，并可早期功能锻炼，防止膝关节强直。     

变压吸附制取医用氧技术的研究

对变压吸附制医用氧过程中的吸附剂选择、流程开发、多层过滤系统等技术问题进行了研究，它将有助于变压吸附制氧技术在我国各级医院中的使用。     

Patella Resurfacing in Total Knee Arthroplasty: A Series of 1280 Patients at Midterm Follow-Up

Background

The management of patella in total knee arthroplasty (TKA) is a controversial topic. The elevated risk of patellofemoral complications seems to support those who are not eager to perform such procedure. The aim of this study is to carry out a retrospective assessment of patients who underwent patellar resurfacing during TKA from 2004 to 2009.