髌骨稳定性与髌股关节炎MRI表现相关性研究

目的 研究髌骨位置四项描述指标与髌股关节炎(PFOA) MRI特征之间相关性.方法 搜集PFOA患者87例,正常人群35名.对膝关节进行MRI检查,评估髌骨长度率(PLR)、滑车沟(SA)、髌骨外侧倾斜角(LT-PA)、二等分处平移(BO)四项指标与髌股内外侧关节面软骨形态改变和骨髓水肿样病变(BML)的相关性.结果 (1)PLR与软骨缺损程度和外侧BML相关(r=0.674、0.734、0.675,P＜0.01),差异有统计学意义.(2)SA与软骨缺损和外侧BML相关(r=0.541、0.664、0.646,P＜0.05),差异有显著统计学意义.(3)最小LPTA(9°～14°)与外侧软骨缺损相关性大,OR(95％ CI)=1,但最大LPTA(23°～ 29°)与外侧软骨缺损相关性小,OR(95％ CI) =0.4(0.3 ～0.6).LPTA与外侧BML相关性也有同样的趋势.(4)BO值与内侧软骨丢失和外侧BML相关(r=0.544、0.459,P＜0.05),差异有显著统计学意义.结论 四项髌骨稳定性指标与髌股关节软骨缺损及外侧关节面骨髓水肿程度都存在着相关性,但对内测关节骨髓水肿程度影响不大.四项髌骨稳定性指标对于PFOA有一定的评估价值.     

无症状成人颈椎矢状位曲度分析及其与全脊柱矢状位参数的关系

目的:探讨正常亚洲黄种人群颈椎矢状位曲度及其与全脊柱矢状位参数的关系。方法:采用影像学分析对132名成人无症状志愿者进行研究,所有志愿者行全脊柱正、侧位X线检查及中立位颈椎侧位片,测量颈椎矢状位参数包括C0-C2角(Occiput-C2 angle)、C2-C7角(C2-C7 angle)、C2-C7矢状面轴向距离(sagittal vertical axis,SVA)、头部重心(center gravity of head,CGH)~C7 SVA(CGH-C7 SVA)、C2-CGH SVA,和胸椎矢状位参数:T1倾斜角(T1 slope)、胸椎后凸角(thoracic kyphosis,TK),脊柱-骨盆的方向性参数:腰椎前凸角(lumbar lordosis,LL)、骨盆入射角(pelvic incidence,PI)、骶骨倾斜角(sacral slope,SS)及全脊柱矢状位参数:脊柱骶骨角(spinal sacral angle,SSA)、C7-S1的矢状面轴向距离(C7-S1 SVA)。使用Toyama等颈椎矢状位序列分型方法将所有志愿者分为三组:前凸组,后凸组,变直或鹅颈畸形组,并比较三组人群各参数间差异。使用皮尔逊相关分析和单因素ANOVA分析相关数据。结果:C0-C2角的平均值是15.13°±6.69°,C2-C7角的平均值是12.03°±7.64°。C2-C7 SVA平均值是18.67±7.96mm,CGH-C7 SVA的平均值是22.95±12.18mm,CGH-C2 SVA的平均值是7.08±5.38mm,T1 slope平均值是26.33°±7.01°。三组志愿者中,前凸组共43名(占32.6%),变直或鹅颈畸形组共74名(占56.1%),后凸组15名(占113%)。C2-C7角与T1 slope(r=0.422)相关,T1 slope与TK(r=0.434)、TK与LL(r=0.574),LL与SS(r=0.459),SS与PI(r=0.727)相关。三种志愿者中C2-C7角,CGH-C7SVA,Tl slope,TK在三组间两两比较均有显著统计学差异。结论:部分无症状成人亦存在颈椎的变直或鹅颈畸形甚至后凸改变。颈椎后凸表现可能更多的是一个局部问题而非整体脊柱骨盆参数异常。     

Long-term neurosensory disturbances after modified sagittal split osteotomy

We have investigated the long-term incidence of neurosensory disturbances after modified bilateral sagittal split osteotomy, and identified associated risk factors. We prospectively studied 376 patients, and their self-reported neurosensory disturbances were evaluated six months, and one, two, and three years postoperatively. The correlations between the following risk factors and neurosensory disturbances were investigated using univariate analysis and stepwise multivariate analysis: age at operation, sex, type of movement (advancement, setback, or rotation), concurrent genioplasty, type of detachment, iliac crest bone graft, and use of dicalcium phosphate synthetic bone graft. Probabilities of less than 0.05 were accepted as significant. Three years postoperatively, 57 patients (15%) reported altered sensation of the lower lip or chin. Older age correlated significantly with neurosensory disturbances (p < 0.0001). Greater mandibular advancement correlated with postoperative “positive” neurosensory phenomena (right side p = 0.08; left side p = 0.03). Intraoperative surgical manipulation of the left inferior alveolar nerve was significantly associated with postoperative hypoaesthesia (p = 0.014). Older age at surgery, extensive mandibular advancement, and surgical manipulation of the left inferior alveolar nerve, were associated with long-term neurosensory disturbances after modified bilateral sagittal split osteotomy. The modified operation seems to safeguard the inferior alveolar nerve from transection, without causing damage to other nerves.     

Outcomes of anterior disc displacement and condylar remodelling for sagittal fracture of the mandibular condyle in children after closed treatment

The aim of this study was to evaluate the outcomes of temporomandibular joint (TMJ) anterior disc displacement and condylar remodelling for sagittal fracture of the mandibular condyle (SFMC) in children. Disc displacement was observed in 20 patients with 24 SFMCs (age 4–12 years) via magnetic resonance imaging. After 6 months of closed treatment (T1), the joints were categorized based on the displaced disc status as complete reduction (DCR) or incomplete reduction (DICR). Moreover, condylar remodelling was compared between the groups using cone beam computed tomography images of the TMJ obtained at T1 and at the 1-year follow-up (T2; 15 patients with 18 displaced SFMCs). At T1, 17 of 24 joints with SFMC were assigned to the DCR group and six to the DICR group; one unilateral SFMC case developed ankylosis. Condylar depth and height differed significantly between the groups at T1, but not at T2. Intra-group comparison exhibited significant changes in the condylar depth and height over time in the DICR group. Thus, most of the anteriorly displaced discs (17/24, 70.8%) achieved reduction following closed treatment. Although sustained anterior disc displacement was associated with an increased depth and reduced height of the condyle, no clinical impairment was noted unless ankylosis developed.     

Computer navigation experience in hip resurfacing improves femoral component alignment using a conventional jig

Background:

The use of computer navigation has been shown to improve the accuracy of femoral component placement compared to conventional instrumentation in hip resurfacing. Whether exposure to computer navigation improves accuracy when the procedure is subsequently performed with conventional instrumentation without navigation has not been explored. We examined whether femoral component alignment utilizing a conventional jig improves following experience with the use of imageless computer navigation for hip resurfacing.

Materials and Methods:

Between December 2004 and December 2008, 213 consecutive hip resurfacings were performed by a single surgeon. The first 17 (Cohort 1) and the last 9 (Cohort 2) hip resurfacings were performed using a conventional guidewire alignment jig. In 187 cases, the femoral component was implanted using the imageless computer navigation. Cohorts 1 and 2 were compared for femoral component alignment accuracy.

Results:

All components in Cohort 2 achieved the position determined by the preoperative plan. The mean deviation of the stem–shaft angle (SSA) from the preoperatively planned target position was 2.2° in Cohort 2 and 5.6° in Cohort 1 (P = 0.01). Four implants in Cohort 1 were positioned at least 10° varus compared to the target SSA position and another four were retroverted.

Conclusions:

Femoral component placement utilizing conventional instrumentation may be more accurate following experience using imageless computer navigation.     

Computed tomographic evaluation of femoral component rotation in total knee arthroplasty

Background:

Optimal femoral component rotational alignment in total knee arthroplasty (TKA) is crucial to establish a balanced knee reconstruction. Unbalanced knees can lead to instability, patellofemoral problems, persistent pain, stiffness, and generally poorer outcomes including early failure. Intraoperative techniques to achieve this optimal femoral component rotation include the use of the transepicondylar axis (TEA), the posterior-condylar-cut-parallel-to-the-tibial-cut (PCCPTC) technique and the anteroposterior axis technique (Whiteside''s line). The purpose of this study was to compare the PCCPTC technique to the TEA technique using computed tomography (CT) scans to assess femoral component rotational alignment.

Materials and Methods:

This study used postoperative CT scans to compare the degree of femoral component rotation obtained with the use of PCCPTC technique and the TEA. The femoral component rotation of 30 TKA was measured on postoperative CT scans the angle of deviation between the two lines radiographic trans-epicondylar axis (rTEA) and femoral prosthesis posterior condylar line (FPPCL) was determined. This angle represented the rotation of the femoral component relative to the true rTEA.

Results:

The degree of rotation measured 2.67 ± 1.11 degrees in the PCCPTC group and 5.60 ± 1.64 degrees in the TEA group.

Conclusion:

The use of the TEA technique for determining rotational alignment in TKR results in excessive external rotation of the femoral component compared to the PCCPTC technique.     

Influence of Gap Balance on the Sagittal Movement of a Specific Mobile Bearing Floating Platform Design in Total Knee Arthroplasty

We analyzed 119 knees implanted with mobile bearing floating platform prostheses using the navigation-assisted gap balancing technique to analyze the relationship between intraoperative sagittal movement of floating platforms and soft tissue balancing. The 95 (79.8%) knees were classified into the positive rollback group (mean insert posterior rollback 5.86 ± 1.24 mm), and the remaining 24 (20.2%) into the negative rollback group. Lateral flexion gap (LFG) differed significantly between knees with positive and negative rollback (20.5 ± 1.7 mm vs 22.1 ± 1.7 mm, P = .021). Only LFG significantly influenced the occurrence of bearing sagittal movement. Sagittal translation of the insert occurred in about 80% of knees implanted with mobile bearing floating platforms in TKA, and was affected by flexion gaps, especially on the lateral side.     

Isocentric 3-Dimensional C-Arm Imaging of Component Alignments in Total Knee Arthroplasty With Potential Intraoperative and Postoperative Applications

An intraoperative imaging tool for total knee arthroplasty could help avoid poor clinical outcomes related to malalignment. We investigated the feasibility of using isocentric (ISO-C) fluoroscopic imaging for this purpose. Three-dimensional ISO-C and computed tomographic (CT) images were acquired from 6 cadaveric specimens implanted with standard knee arthroplasty components and analyzed to determine rotational alignments. In comparison with standard CT measures, the ISO-C–based measures had overall accuracies (determined as root mean square error) of 0.8° and 1.3° and corresponding SDs of 1.3° and 1.4° for the femoral and tibial components, respectively. With ISO-C imaging, it is possible to measure rotational alignment in knee arthroplasty with accuracy and repeatability comparable with CT. Isocentric imaging has strong potential as an intraoperative tool to accurately align arthroplasty components.     

Accelerometer-Based,Portable Navigation vs Imageless,Large-Console Computer-Assisted Navigation in Total Knee Arthroplasty : A Comparison of Radiographic Results

Computer-assisted surgery (CAS) systems improve alignment accuracy in total knee arthroplasty (TKA) but have not been widely implemented. Eighty knees underwent TKA using an accelerometer-based, portable navigation device (KneeAlign 2; OrthAlign Inc, Aliso Viejo, California), and the radiographic results were compared with 80 knees performed using a large-console, imageless CAS system (AchieveCAS; Smith and Nephew, Memphis, Tennessee). In the KneeAlign 2 cohort, 92.5% of patients had an alignment within 3° of a neutral mechanical axis (vs 86.3% with AchieveCAS, P < .01), 96.2% had a tibial component alignment within 2° of perpendicular to tibial mechanical axis (vs 97.5% with AchieveCAS, P = .8), and 94.9% had a femoral component alignment within 2° of perpendicular to the femoral mechanical axis (vs 92.5% with AchieveCAS, P < .01). The mean tourniquet time in the KneeAlign 2 cohort was 48.1 ± 10.2 minutes vs 54.1 ± 10.5 minutes in the AchieveCAS cohort (P < .01). Accelerometer-based, portable navigation is as accurate as large-console, imageless CAS systems in TKA.     

Asymmetry of the Leg Alignment Affects Trunk Bending in the Coronal Plane After Unilateral Total Knee Arthroplasty

Unilateral total knee arthroplasty (TKA) would produce asymmetric changes of lower extremity in patients with bilateral varus deformity. Our purpose was to investigate whether asymmetry of the leg alignment would affect trunk bending in the coronal plane after unilateral TKA. Twenty patients (mean 76 years old) with bilateral end-stage knee osteoarthritis (OA) participated. Spine images during relaxed standing were obtained on pre- and postoperative day 21. As a result, the shoulder tilted more to the TKA side and the pelvis inclined more to the contralateral OA side. These results suggested that the trunk would bend away from the contralateral OA side after unilateral TKA in patients with bilateral end-stage knee OA and varus deformity. Asymmetry of the leg alignment led to asymmetric trunk bending.