三维骨建模系统在人工全膝关节置换时旋转对位的作用

目的 为了进行人工全膝关节置换时假体旋转对位的量化研究,探讨三维骨建模的计算机辅助手术系统对量化操作的精确性和有效性. 方法 2002年11月 - 2003年6月,采用三维骨建模 Ceravision 系统对 21 例 21 膝保守治疗无效的三间隔骨性关节炎患者行人工全膝关节置换术.男5例5膝,女16例16膝;年龄64～79岁,平均 72.4 岁.左膝10例,右膝11例.主要临床表现为膝关节疼痛和活动受限.病程2～10年.14例膝内翻,7例膝外翻.根据相关的临床体检、影像学和导航系统资料,对术中假体旋转对位量值,并对术后3个月膝关节活动度、膝关节松弛度和髌骨稳定性进行分析. 结果 全部患者术后切口均Ⅰ期愈合.21 例患者均获随访12～16个月,平均13.3个月.术中股骨假体旋转对位内旋 1°～外旋 5°,胫骨假体旋转对位内旋 0°～外旋5°.其中膝内翻患者,股骨假体旋转对位外旋 1°～外旋5°,胫骨假体旋转对位外旋2°～外旋5°膝外翻患者,股骨假体旋转对位内旋1°～外旋4°,胫骨假体旋转对位内旋0°～外旋 4°.术后3个月膝关节活动度,最大屈膝度为 105～130°,平均 115°;膝关节额面松弛度,内侧 0.2～0.5 cm,平均 0.27 cm,外侧 1.0～2.5 cm,平均 1.7 cm.无膝痛、髌骨失稳和脱位等并发症发生. 结论 应用三维骨建模的计算机辅助手术系统,可针对患者个体精确地进行假体旋转对位.     

Does Residual Varus Alignment Cause Increasing Varus Laxity at a Minimum of Five Years After Total Knee Arthroplasty?

Background

The purpose of this study is to investigate whether varus-valgus laxity of cruciate-retaining (CR) total knee arthroplasty (TKA) changes between 1 year and >5 years after surgery based on postoperative limb alignment.

Postoperative limb alignment and its determinants after minimally invasive Oxford medial unicompartmental knee arthroplasty

One hundred twenty-two consecutive minimally invasive Oxford phase 3 medial unicompartmental knee arthroplasties in 109 patients were evaluated for postoperative limb alignment and the influence of factors such as preoperative limb alignment, age, body mass index, sex, insert thickness, and surgeon's experience. The mean mechanical preoperative hip-knee-ankle (HKA) angle of 172.2° ± 3.1° improved to 177.1° ± 2.9° postoperatively. In 75% of the limbs, the HKA angle was restored to within an acceptable alignment of 177° ± 3°, 14% of the limbs were in excessive varus (<174°), and 11% were in valgus (>180°). Only preoperative HKA angle was predictive of postoperative HKA angle. Although most of the limbs had acceptable limb alignment after unicompartmental knee arthroplasty, limbs with more severe preoperative varus deformity had a tendency to remain in excessive varus, and limbs with lesser preoperative varus deformity had a greater tendency to go into valgus postoperatively.     

Axial alignment of the lower extremity in Chinese adults

BACKGROUND: The restoration of normal axial alignment of the lower extremity is important to surgeons who perform reconstructive surgery of the knee. However, data on the normal alignment of the lower extremity in Chinese adults are not available. METHODS: The axial alignment of the lower extremity in twenty-five adult male and twenty-five adult female volunteers of southern Chinese origin was measured on weight-bearing radiographs of the entire lower limb. The mean age was twenty-four years for the male volunteers and twenty-three years for the female volunteers. The results were compared with those of two similar studies of white volunteers in the United States. RESULTS: The medial inclination of the tibial plateau in the Chinese subjects (mean and standard deviation, 5.4 +/- 2.5 degrees for women and 4.9 +/- 2.3 degrees for men) was greater than the commonly reported 3 degrees. The extremities of the Chinese women were found to have a mean of 2.2 +/- 2.5 degrees of varus alignment, and those of the Chinese men had a mean of 2.2 +/- 2.7 degrees of varus alignment. CONCLUSIONS: Compared with the white subjects described in the studies by Moreland et al. and Hsu et al., the Chinese subjects had significantly larger medial inclination of the knee joint (knee-joint obliquity) (p < 0.005) and the female Chinese subjects had significantly more varus alignment of the lower extremity (p < 0.025). CLINICAL RELEVANCE: Five degrees of external rotation of the femoral component, instead of the commonly reported 3 degrees, may be required to obtain a rectangular flexion gap in total knee arthroplasty in Chinese patients. The racial difference in the knee-joint obliquity may contribute to the racial difference in the ratio of knee osteoarthritis to hip osteoarthritis. Additional studies are necessary to confirm this relationship.     

Decrease of osteosclerosis in subchondral bone of medial compartmental osteoarthritic knee seven to nineteen years after high tibial valgus osteotomy

Osteosclerosis of the subchondral bone was measured by densitometer on plain radiographs in 55 medial compartmental osteoarthritic knees of 40 patients who were treated with high tibial valgus osteotomy for correction of varus deformity. The ratio of the osteosclerosis value of the medial side of the knee to that of the lateral side (Medial/Lateral ratio) was calculated and used as a parameter. The Medial/Lateral ratio of osteosclerosis decreased rapidly within three years after osteotomy at the reference points of the femur and the tibia. Even 7 to 19 years after osteotomy, a decrease of the ratio was noted in 16 knees with a standing femorotibial angle (FTA) less than 168 degrees (12 degrees of anatomical valgus angulation). This was interpreted to mean that osteosclerosis of the medial condyle decreased compared with that of the lateral condyle after overcorrection of varus deformity. In the cases of more than 7 years after high tibial osteotomy, a positive straight regression line was drawn by calculation between Medial/Lateral ratio and postoperative limb alignment expressed by standing femorotibial angle, with coefficient of correlation (gamma) of 0.295 (p < 0.01).     

Tibial tubercle osteotomy in total knee arthroplasty surgery

Tibial tubercle osteotomy (TTO) is a recognized technique for improving exposure when performing total knee arthroplasty surgery. Forty-two patients were reviewed at a mean of 8 years after TTO. Preoperatively, mean extension was 8 degrees +/- 14 degrees , mean flexion 74 degrees +/- 30 degrees , and Knee Society score 73 +/- 37. At latest follow-up, mean extension was 4 degrees +/- 15 degrees , mean flexion 91 degrees +/- 22 degrees , and Knee Society score 124 +/- 42.6 (P < or = .0001). Seventy-three percent of patients had an excellent/good score at latest follow-up. Twenty-five percent of patients experienced no extensor lag, and 66% of extensor lags had resolved within 6 months. Mean time for osteotomy union was 14 weeks. In this series, TTO performed to enhance surgical exposure did not adversely affect the outcome after total knee arthroplasty but resulted in serious complications in 5% of patients.     

Shape of the joint gap for 90° and 120° knee flexion after total knee arthroplasty

BACKGROUND: The joint gap is set rectangular at 90 degrees flexion during total knee arthroplasty (TKA). However, the condition of the joint gap in deep knee flexion is obscure. METHODS: The method for obtaining a posteroanterior view radiograph of the knee at 90 degrees flexion (the epicondylar view) was modified, and a method to obtain an anteroposterior view radiograph at 120 degrees flexion (deep flexion view) was established. With this method, subjects lie on the radiography table with their thighs placed on a device so their lower legs hang down in neutral rotation with a 1.5-kg weight attached to the ankle. The joint gap angle and medial and lateral joint space widths were measured on epicondylar view and deep flexion view radiographs in 20 normal male subjects, 20 normal female subjects, and 20 subjects after TKA. RESULTS: The joint gap was almost rectangular at two flexion angles in normal subjects. In the implanted knees, the gap angle was 1.4 degrees varus +/- 3.3 degrees (mean +/- standard deviation), and no significant difference was found between medial and lateral joint space widths at 90 degrees flexion. In contrast, the gap angle was 2.5 degrees varus +/- 2.5 degrees and the lateral joint space width was significantly wider than the medial joint space width at 120 degrees flexion (P < 0.001). The gap angle was more varus with a significant difference in the implanted knees than that in the normal subjects at 120 degrees flexion (P < 0.001). CONCLUSIONS: The joint gap was trapezoidal with a wider lateral side at 120 degrees flexion even though it was almost rectangular at 90 degrees flexion after TKA.     

Total knee arthroplasty with conventional or navigated technique: comparison of the learning curves in a community hospital

We performed a comparative study of the short-term radiological and clinical results after implantation of an unconstrained TKA with preservation of the posterior cruciate ligament with a conventional (50 cases--group A) or navigated (50 cases--group B) technique. The primary criterion was the postoperative leg coronal alignment measured on 3-month postoperative anteroposterior long-leg radiographs by the HKA angle: the expected alignment was 180 degrees +/- 3 degrees. The mean post-operative HKA angle was 180 degrees +/- 3 degrees in group A and 180 degrees +/- 1 degrees in group B (p = 0.15). Thirty-four cases in group A and all 50 cases in group B were in the desired range (p < 0.001). The navigated system used in this study allowed for a significantly better alignment accuracy than the conventional implantation technique. Acceptable routine implantation was achieved during the time of the study (first 50 cases). We can thus hypothesise that the learning curve of the navigated technique used is not any longer than the learning curve of a conventional implantation technique.     

The effect of simulated knee flexion on sagittal spinal alignment: novel interpretation of spinopelvic alignment

Introduction

Many studies regarding spinal sagittal alignment were focused mainly on above-hip structures, not considering the knee joint. Knee–spine syndrome was proposed earlier, but the mechanism of this phenomenon has not been revealed. The aim of the study was to demonstrate how spinopelvic alignment and sagittal balance change in response to simulated knee flexion in normal non-diseased population.

Methods

Thirty young male were enrolled in the study cohort. Two motion-controlled knee braces were used to simulate knee flexion of 0°, 15°, and 30° settings. Whole spine and lower extremity lateral radiographs were taken at each knee setting of 0°, 15°, and 30° flexion. Spinal and pelvic parameters were measured, including two angular parameters, femoropelvic angle (FPA) and femoral tilt angle (FTA).

Results

The following equation can be made; PT (pelvic tilt) = FPA + FTA. The mean values of FPA and lumbar lordosis decreased significantly at 15° and 30° knee settings compared to the parameters at the 0° knee setting, while the mean values of pelvic tilt and sacral slope rarely changed. Results also showed FTA was not correlated with PT, but strongly correlated with FPA (R = ?0.83, p < 0.01).

Conclusions

The knee flexion resulted in decrease of lumbar lordosis without a significant change of pelvic posture in non-diseased population group.     

Foot rotational effects on radiographic measures of lower limb alignment.

INTRODUCTION: Surgical planning of high tibial osteotomy (HTO) typically requires the measurement of lower limb alignment from standing anteroposterior radiographs. Although every effort is made to maintain a standardized patient position, factors such as pain or anatomic constraints may necessitate acquiring the radiograph in a less than optimal patient position. One such constraint is natural rotation of the feet with respect to the tibia. The purpose of the present study was to investigate the magnitude of the effect of foot rotation on radiographic measures of lower limb alignment. METHODS: We analyzed 19 lower limbs from radiographs obtained from 10 people who reported to an orthopedic injuries clinic. Each patient was radiographed in 3 positions: 15 degrees of internal foot rotation, no foot rotation and 15 degrees of external foot rotation. We measured and compared the mechanical axis angle (hip-knee-ankle) and the mechanical axis deviation from each position. RESULTS: Compared with the position with no foot rotation, internal foot rotation resulted in less measured varus alignment and less mechanical axis deviation from the knee joint centre, whereas external foot rotation produced greater measured varus alignment and increased mechanical axis deviation from the knee joint centre. CONCLUSIONS: These results indicate that patient positioning is an important factor when measuring lower limb alignment from radiographs. As a result, special care must be taken when acquiring these radiographs for use in planning surgical procedures such as HTO.     

Current Data Do Not Support Routine Use of Patient-Specific Instrumentation in Total Knee Arthroplasty

The purpose of this systematic review and meta-analysis is to compare patient-specific instrumentation (PSI) versus standard instrumentation for total knee arthroplasty (TKA) with regard to coronal and sagittal alignment, operative time, intraoperative blood loss, and cost. A systematic query in search of relevant studies was performed, and the data published in these studies were extracted and aggregated. In regard to coronal alignment, PSI demonstrated improved accuracy in femorotibial angle (FTA) (P = 0.0003), while standard instrumentation demonstrated improved accuracy in hip-knee-ankle angle (HKA) (P = 0.02). Importantly, there were no differences between treatment groups in the percentages of FTA or HKA outliers (>3 degrees from target alignment) (P = 0.7). Sagittal alignment, operative time, intraoperative blood loss, and cost were also similar between groups (P > 0.1 for all comparisons).     

综合手术治疗膝关节骨性关节炎合并膝内翻

目的 为使膝关节骨性关节炎合并膝内翻的年轻患者延缓行全膝关节置换,探讨股骨内髁马赛克植骨、髌骨成形并胫骨高位截骨综合手术治疗膝关节骨性关节炎合并膝内翻的临床疗效.方法 2004年6月-2006 年2月,对8例10膝骨性关节炎合并膝内翻患者行综合手术治疗.其中男2例3膝,女6例7膝;年龄42～56岁.左膝3例,右膝3例,双膝2例.患者均表现为行走或站久后疼痛.X 线片示股胫关节及髌骨边缘骨质增生,以内侧为重,髌股关节间隙变窄或消失,膝关节内侧间隙明显变窄.股胫角185～200°,平均 190°;HSS 膝关节评分为55～75分,平均60分.膝痛1～12年,平均5年. 结果 术后切口均Ⅰ期愈合,无早期并发症发生.患者均获随访7～24个月,平均15个月.患者截骨部位均于8～11 周达临床愈合,平均9周.股胫角矫正15～30°,平均 20°,基本恢复正常负重力线,膝关节外翻角 10°.术后关节活动度为 100～120°,较术前增加 5～20°,平均增加 10°.X 线片示膝关节内翻畸形基本纠正,截骨处无移位,内固定无松动、断裂.术后6个月HSS膝关节评分75～88分,平均80分. 结论 股骨内髁马赛克植骨使关节软骨得到一定程度的修复重建,髌骨成形有效解决膝前区疼痛,胫骨高位截骨矫正异常负重力线,三者结合,疗效肯定.     

Evidence and mechanism by which upper partial fibulectomy improves knee biomechanics and decreases knee pain of osteoarthritis

To investigate the change in short‐term clinical outcomes and biomechanical properties of the knee in response to upper partial fibulectomy and to probe into the biomechanical mechanism underlying the clinical benefits of upper partial fibulectomy for medial compartment knee osteoarthritis (KOA). A total of 29 patients with medial compartment KOA underwent upper partial fibulectomy. Visual analog scale (VAS) pain, the hospital for special surgery knee score (HSS), hip‐knee‐ankle (HKA) angle (measured in the frontal plane), and flexion/extension range of motion of the knee were assessed before and up to 6 months after surgery. Patients and 20 healthy controls were evaluated by 3D gait analysis and dynamic lower limb musculoskeletal analysis. Both VAS pain and HSS score were significantly improved (p < 0.001) one day after surgery and steadily improved during the subsequent 6 months. HKA angle improved (p = 0.025) immediately and remained stable by 3 months after surgery. The decreased overall peak KAM (decreased by 11.1%) and increased HKA angle (increased by 1.80 degrees from a more varus to more neutral alignment) of affected and operated side by 6 months after surgery were observed. Muscle activity of biceps femoris caput longum of affected and operated side increased immediately and was equivalent to healthy controls by 6 months after surgery (p = 0.007). This pilot study provides biomechanical evidence of benefit from partial upper fibulectomy and indicates a plausible rationale for the improvement in clinical symptoms. Long‐term clinical outcomes and precise biomechanical mechanism of partial upper fibulectomy should be further investigated. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2099–2108, 2018.

     

Intraoperative measurement of knee kinematics in reconstruction of the anterior cruciate ligament

Our objectives were to establish the envelope of passive movement and to demonstrate the kinematic behaviour of the knee during standard clinical tests before and after reconstruction of the anterior cruciate ligament (ACL). An electromagnetic device was used to measure movement of the joint during surgery. Reconstruction of the ACL significantly reduced the overall envelope of tibial rotation (10 degrees to 90 degrees flexion), moved this envelope into external rotation from 0 degrees to 20 degrees flexion, and reduced the anterior position of the tibial plateau (5 degrees to 30 degrees flexion) (p < 0.05 for all). During the pivot-shift test in early flexion there was progressive anterior tibial subluxation with internal rotation. These subluxations reversed suddenly around a mean position of 36 +/- 9 degrees of flexion of the knee and consisted of an external tibial rotation of 13 +/- 8 degrees combined with a posterior tibial translation of 12 +/- 8 mm. This abnormal movement was abolished after reconstruction of the ACL.     

Computer-assisted technique versus intramedullary and extramedullary alignment systems in total knee replacement: a radiological comparison

Malalignment in total knee replacement (TKR) is frequently associated with earlier failure and poor functional results. The authors compare the radiological results achieved in three consecutive series of TKRs using a computer-based alignment system (38 cases), a totally intramedullary alignment system (40 cases) and a totally extramedullary alignment system (37 cases). The frontal-femoral-component angle (FFC), the frontal-tibial-component angle (FTC), the hip-knee-ankle angle (HKA) and the sagittal orientation of the tibial component (slope) were evaluated 12 months after operation. The results did not show any statistically significant differences between the mean values of FFC, FTC, HKA angles and tibial slope among the three groups. However in the extramedullary alignment group there was a statistically higher percentage of TKRs with abnormal FFC and HKA angles. Furthermore all the implants in the computer aligned group were aligned within 4 degrees both of an ideal HKA and tibial slope.     

Does axial limb rotation affect the alignment measurements in deformed limbs?

The long-term outcome of total knee arthroplasty and femoral or tibial osteotomy is related to the ability of the surgeon to achieve the desired alignment based on preoperative planning. This study evaluates the effect of axial rotation on measured tibiofemoral angles and the angle formed between the anatomic and mechanical axes of the femur in lower extremities with valgus and varus deformities. A comparison study of the measured tibiofemoral angles indicated a statistically significant effect in models with severe vagus or varus deformity when rotated 10 degrees internally or externally. In the second part of the study, the measured angle between the anatomic and mechanical axes of the femur never varied by more than 1 degree, despite a 40 degrees are of rotation. The results of the study indicate the tibiofemoral angle measurements are more sensitive to axial limb rotation in lower extremities with valgus or varus deformity than are normally aligned limbs. In preoperative planning of total knee arthroplasty, the measured angle between the anatomic and mechanical axes of the femur is less effected by limb rotation, regardless of the degree of valgus or varus deformity.     

全膝关节置换术中股骨内髁滑移截骨治疗伴有关节外畸形的膝内翻

目的：探讨股骨内髁滑移截骨术（medial condyle sliding osteotomy, MCSO）在全膝关节置换术中纠正患者内翻膝关节外畸形的临床疗效。方法通过回顾性研究2013年1月至2015年12月在第三军医大学附属西南医院关节外科中心于全膝关节置换术中采用MCSO在关节内纠正股骨侧的关节外内翻畸形的12例患者,统计该组患者手术前后的股骨远端外侧力线角（mechanical lateral distal femoral angle, mLDFA）、髋-膝-踝（hip?knee?ankle, HKA）角、疼痛视觉模拟量表（visual analogue scale, VAS）评分及美国膝关节协会（American Knee Society, AKS）综合评分系统中的膝评分和功能评分等,评价MCSO纠正关节外的内翻畸形的效果。结果本组患者随访6~40个月,无感染、骨折、假体松动、截骨不愈合等并发症发生。本组患者手术前后的mLDFA分别为117.4°±4.7°、91.6°±1.4°;手术前后的HKA角分别为167.2°±9.8°、179.6°±1.6°;手术前后的VAS评分分别为（6.4±1.1）分、（1.8±1.5）分;手术前后的AKS膝评分分别为（60.2±17.6）分、（92.6±9.4）分;手术前后的AKS功能评分分别为（69.4±21.3）分、（87.6±14.9）分。手术前后以上指标的差异均有统计学意义（均P＜0.05）。结论在合并关节外畸形的内翻膝的关节置换手术中,采用MCSO技术可以正确纠正内翻力线,更容易实现伸屈间隙平衡,达到满意的手术疗效。能有效避免对膝关节后内侧和内侧组织结构的过度松解,从而避免单纯依赖软组织松解而导致的屈曲位内侧间隙松弛及髌股关节对位不良等问题。     

Axial radiography of the distal femur to assess rotational alignment in total knee arthroplasty

A method for taking an axial radiograph of the distal femur was developed to see the epicondyles and posterior condyles of the femur. It was hypothesized that these radiographs would be acceptable for evaluating rotational alignment in total knee arthroplasty with comparable reproducibility and good correlation to the results obtained with computed tomography images. Radiographs were obtained of 50 knees in 32 patients having total knee arthroplasty. The radiographs were taken while the patients were with the knee in 90 degrees flexion. The angle between the clinical epicondylar axis and the posterior condylar axis (twist angle) was measured and compared with the results obtained by conventional computed tomography. The interobserver variation in the axial radiography was less than or comparable to the computed tomography method. The mean discrepancy between the two methods (+/- standard deviation) was 0.5 degrees +/- 0.4 degrees (range, 0-1.9 degrees ), and a strong correlation was observed. This plain radiography is acceptable for evaluation of femoral component rotation with comparable reproducibility and correlation to the results with computed tomography. It has several advantages regarding cost, radiation dose, and lack of scatter when used for postoperative assessment.     

Knee alignment in professional tennis players

This study determined lower-limb alignment and knee geometry in professional tennis players and compared the data with those from nonathletic individuals. Twenty-four radiographs from 12 asymptomatic players (mean age: 23.4+/-3.8 years) were prospectively studied. The three angles most useful for describing limb alignment and knee geometry in the coronal plane were measured: hip-knee-ankle, condylar-hip, and plateau-ankle. The condylar-plateau angle, frontal foot rotation angle, and the relationship between the mechanical axis and tibial plateau also were calculated. Varus limb alignment was predominant and the mechanical axis passed medially through the knee center; there was increased valgus inclination of the distal femur, varus angulation of the tibial plateau, near parallel alignment of the joint, and exaggerated external foot rotation. Hip-knee-ankle, condylar-hip, plateau-ankle, and frontal foot rotation angles were significantly different (P<.05, two-tailed t test) from previously reported angles of nonathletic individuals. Variations, probably due to repetitive dynamic demands imposed on lower limbs from an early age, seem to involve both femoral condyles and proximal tibial metaphyses, maintaining normal parallel joint alignment.