Clinical and biomechanical assessment of patella resurfacing in total knee arthroplasty

BACKGROUND: Currently there is a limited understanding of the factors influencing range of motion by comparing patellar resurfacing vs non-resurfacing in total knee arthroplasty during activities of daily living. A recent meta-analysis of patellar replacement confirms better outcome with patella resurfacing; however, the result can be influenced by many other factors, such as: component design, surgeon experience, and technical aspects of the surgery. This study compares the biomechanics of the knee in patients after total knee arthroplasty with and without patellar resurfacing during stair climbing. METHODS: Forty-seven patients with total knee arthroplasty were assessed at the mean follow-up of 24 months. In all of them a posterior stabilised fixed bearing prosthesis (Optetrak PS, Exactech) was implanted. Twenty-six patients were treated without patellar resurfacing and 21 with patellar resurfacing. Clinical evaluations were performed using the International Knee Society and the Hospital for Special Surgery scores. Ten patients with patellar resurfacing and 10 patients without patellar resurfacing were also studied with motion analysis during stair climbing; 10 healthy subjects were studied for statistical comparison. FINDINGS: Clinical passive knee flexion, International Knee Society Function and Hospital for Special Surgery scores were significantly higher in the patellar resurfacing group. During stair climbing, active knee joint range of motion during the stance phase was greater in patients with patellar resurfacing. The maximum adduction moment was significantly higher in the group without patellar resurfacing. INTERPRETATION: Patients with patellar resurfacing demonstrated better clinical scores, and kinematic and kinetic data while ascending stairs.     

Functional performance of a total ankle replacement: thorough assessment by combining gait and fluoroscopic analyses

Background

A thorough assessment of patients after total ankle replacement during activity of daily living can provide complete evidence of restored function in the overall lower limbs and replaced ankle. This study analyzes how far a possible restoration of physiological mobility in the replaced ankle can also improve the function of the whole locomotor apparatus.

Methods

Twenty patients implanted with an original three-part ankle prosthesis were analyzed 12 months after surgery during stair climbing and descending. Standard gait analysis and motion tracking of the components by three-dimensional fluoroscopic analysis were performed on the same day using an established protocol and technique, respectively.

Findings

Nearly physiological ankle kinematic, kinetic and electromyography patterns were observed in the contralateral side in both motor activities, whereas these patterns were observed only during stair climbing in the operated side. Particularly, the mean ranges of flexion at the replaced ankle were 13° and 17° during stair climbing and descending, respectively. Corresponding 2.1 and 3.1 mm antero/posterior meniscal-to-tibial translations were correlated with flexion between the two metal components (p < 0.05). In addition, a larger tibiotalar flexion revealed by fluoroscopic analysis resulted in a physiological hip and knee moment.

Interpretation

The local and global functional performances of these patients were satisfactory, especially during stair climbing. These might be associated to the recovery of physiological kinematics at the replaced ankle, as also shown by the consistent antero/posterior motion of the meniscal bearing, according to the original concepts of this ankle replacement design.     

Trunk and lower limb biomechanics during stair climbing in people with and without symptomatic femoroacetabular impingement

BackgroundFemoroacetabular impingement is a pathomechanical hip condition leading to pain and impaired physical function. It has been shown that those with femoroacetabular impingement exhibit altered gait characteristics during level walking and stair climbing, and decreased muscle force production during isometric muscle contractions. However, no studies to-date have looked at trunk kinematics or muscle activation during dynamic movements such as stair climbing in this patient population. The purpose of this study was to compare biomechanical outcomes (trunk and lower limb kinematics as well as lower limb kinetics and muscle activation) during stair climbing in those with and without symptomatic femoroacetabular impingement.MethodsTrunk, hip, knee and ankle kinematics, as well as hip, knee and ankle kinetics and muscle activity of nine lower limb muscles were collected during stair climbing for 20 people with clinical and radiographic femoroacetabular impingement and compared to 20 age- and sex-matched pain-free individuals.FindingsThose with femoroacetabular impingement ascended the stairs slower (effect size = 0.82), had significantly increased peak trunk forward flexion angles (effect size = 0.99) and external hip flexion moments (effect size = 0.94) and had decreased peak external knee flexion moments (effect size = 0.90) compared to the control group.InterpretationFindings from this study indicate that while those with and without femoroacetabular impingement exhibit many biomechanical similarities when ascending stairs, differences in trunk forward flexion and joint kinetics indicate some important differences. Further longitudinal research is required to elucidate the cause of these differences as well as the clinical relevance.     

Delayed onset of quadriceps activity and altered knee joint kinematics during stair stepping in individuals with knee osteoarthritis

OBJECTIVE: To determine if the electromyographic onset of vastus lateralis and kinematic knee joint motion in individuals with knee osteoarthritis (OA) differs from that of asymptomatic persons, during the task of stair stepping. DESIGN: Cross-sectional. SETTING: University laboratory in Australia. PARTICIPANTS: Twenty-five participants with symptomatic knee OA and 33 asymptomatic controls. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Surface electromyography to determine the onset of vastus lateralis activity. Two-dimensional kinematic analysis of sagittal plane knee motion during stance phase of stair ascent and descent. RESULTS: Participants with knee OA showed delayed onset of vastus lateralis activity during stair descent (P<.05) but not ascent. Both groups displayed a similar total range of knee motion. However, during stair descent, participants with OA had less knee flexion during early stance (P<.05) than controls. CONCLUSION: Individuals with knee OA display altered quadriceps function and knee joint kinematics during stair descent. These impairments may have implications for force attenuation across the knee joint and warrant future investigation.     

The use of a lateral wedge insole to reduce knee loading when ascending and descending stairs in medial knee osteoarthritis patients

Background

Stair climbing is a challenging task to the elderly being the task with the first complaint in patients with mild to moderate knee osteoarthritis. Stair climbing results in around six times more compressive load transmitted through the knee joint than walking on level ground. The purpose of this study was to assess whether lateral wedge insoles would reduce medial compartment knee loading when ascending and descending stairs in patients with medial knee osteoarthritis.

Methods

Eight patients with medial knee osteoarthritis were tested in random order with and without a pair of 5° off-the-shelf lateral wedge insoles for two separate activities (stair ascent and stair descent). Kinematic and kinetic data were collected for the lower extremity using a sixteen camera motion capture system and two force plates. Primary outcome measures were the external knee adduction moment and the knee adduction angular impulse.

Findings

During stair ascent and descent, lateral wedge insoles significantly (P < 0.05) reduced the 1st peak external knee adduction moment in early stance (ascent 6.8%, descent 8.4%), the trough in mid stance (ascent 13%, descent 10.7%), 2nd peak in the late stance (ascent 15%, descent 8.3%) and the knee adduction angular impulse compared to the control (standard shoe) with large effect sizes (0.75–0.95).

Interpretation

In this first study on stairs, lateral wedge insoles consistently reduced the overall magnitude of medial compartment loading during stair ascent and descent. Further research is needed to determine the relationship of this with clinical results when ascending and descending stairs with lateral wedge insoles.     

Biomechanical Analysis of Stair Descent in Patients with Knee Osteoarthritis

[Purpose] The purposes of this study were to investigate the lower extremity joint kinematics and kinetics of patients with the knee osteoarthritis (knee OA) during stair descent and clarify the biomechanical factors related to their difficulty in stair descent. [Subjects and Methods] Eight healthy elderly persons and four knee OA patients participated in this study. A 3-D motion analysis system and force plates were employed to measure lower extremity joint angles, ranges of motion, joint moments, joint powers, and ratios of contribution for the joint powers while descending stairs. [Results] Knee joint flexion angle, extension moment, and negative power during the early stance phase in the knee OA group were smaller than those in the healthy subjects group. However, no significant changes in these parameters in the ankle joint were observed between the two subject groups. [Conclusion] Knee OA patients could not use the knee joint to absorb impact during the early stance phase of stair descent. Hence, they might compensate for the roles played by the intact knee joint by mainly using ipsilateral ankle kinematics and kinetics.Key words: Knee osteoarthritis, Stair descent, 3-D motion analysis     

Knee joint moments during stair climbing of patients with anterior cruciate ligament deficiency

OBJECTIVE: To establish the gait adaptations of patients with anterior cruciate ligament deficiency during stair ascent. DESIGN: Joint kinematics and kinetics during stair climbing were measured in both knees of normal subjects and unilateral anterior cruciate ligament deficient patients. BACKGROUND: As there is limited research pertaining to activities other than level walking, the purpose of the current study was to elucidate the gait of patients with anterior cruciate ligament deficiency during stair climbing to determine the effects of the deficiency on knee joint motion and moments as compared with normal knee function. METHODS: A motion analysis system was used to measure and calculate kinematic and kinetic data for six normal subjects and nine patients with unilateral anterior cruciate ligament deficiency during stair ascent on a specially constructed staircase. Left and right leg data were analysed to reveal between-limb differences for each subject. RESULTS: Patients with anterior cruciate ligament deficiency displayed a significant (P < 0.05) reduction of up to 50% in peak knee flexion moments in their involved knee. In the present study where a step height of 15.5 cm was used, peak flexion moments in all subjects' limbs occurred at knee flexion angles of about 40 degrees during single limb support. CONCLUSION: The current study showed that most patients with an anterior cruciate deficient knee adapted their gait during stair ascent. RELEVANCE: As stair climbing is a common activity, its effect on gait is relevant to better understand appropriate treatment and management strategies of patients with anterior cruciate ligament deficient knees.     

The effect of total knee replacement on dynamic support of the body during walking and stair ascent

BACKGROUND: Little is known about the effects of total knee replacement surgery on the contributions of individual joint moments to the total support moment. A better understanding of these effects may enhance rehabilitation protocols and determine factors related to long-term surgical outcome. METHOD: Twenty-one subjects with total knee replacement and 21 controls performed level walking and stair ascent at two testing periods, pre- and 6 months post-surgery. Variables studied included gait velocity, stride length, knee flexion angle, net joint moments of the hip, knee and ankle, and total support moment. Data were analyzed at the first peak vertical ground reaction force. FINDINGS: For level walking, the total support moment, knee extensor moment, and knee flexion angle of total knee replacement patients were less than controls at post-surgery. For stair ascent, the patient group total support moment, ankle plantarflexor moment, and knee flexion angle were less than controls at both testing periods, while knee extensor moment was less than controls at post-surgery. Extensor synergies of the total knee replacement patients revealed less knee and more hip contributions during level walking and larger hip contributions during stair ascent to the total support moment than controls at both testing periods. INTERPRETATION: A feature of total knee replacement gait, pre- and post-surgery, is a stiff knee attitude which may serve to protect the quadriceps. The larger hip extensor contribution to the total support moment observed in the patients may compensate for the diminished knee extensor contribution during level walking and stair ascent.     

Knee kinematics in functional activities seven years after total knee arthroplasty

BACKGROUND: Detailed knowledge of knee kinematics during functional activities is lacking in current studies on the long-term outcome of total knee replacement surgery. The aim of this study was to assess functional knee kinematics using flexible electrogoniometry in patients seven years after unilateral primary total knee arthroplasty for osteoarthritis. METHODS: The knee joint functional movement of a cohort of patients (n=19) with knee osteoarthritis was assessed using electrogoniometry before surgery and 18-24 months and seven years after total knee surgery. The mean age of the patients (11 women and 8 men) at the time of the pre-surgery assessment was 67 years old (SD 8.0). Patient function was also assessed using the Knee Society Score and WOMAC osteoarthritis Index. FINDINGS: The function components of the Knee Society and WOMAC scores were significantly decreased at seven years compared to 18-24 months after surgery (both P<0.05). However, the majority of the functional knee flexion values derived from electrogoniometry did not decrease. Seven years after surgery, knee excursion during ascending and descending stairs was significantly improved compared to 18-24 months after surgery (both P<0.01). INTERPRETATION: The finding that functional knee motion continues to improve between 18-24 months and seven years post-surgery is of interest to both patients and those responsible for their treatment planning. Further, it was shown that the WOMAC and Knee Society Scores do not follow the same trends as the patients' functional knee kinematics seven years after total knee replacement surgery.     

Influence of graft type on sagittal plane knee biomechanics during stair ambulation following anterior cruciate ligament reconstruction

BackgroundBoth graft type and surgical technique for anterior cruciate ligament reconstruction can affect knee biomechanics. Several studies reported the influence of graft type, but few have controlled the surgical technique and fully investigated stair ambulation. This study aimed to compare knee biomechanics during stair ambulation between patients treated with hamstring tendon graft and those treated with patellar tendon graft when anterior medial portal technique was used to drill femoral tunnel.MethodsTwo groups of patients (patellar tendon, n = 18; hamstring tendon, n = 18) at average 12 months after reconstruction surgery were recruited to ascend and descend a customized staircase in a gait lab. Joint kinematics and kinetics were calculated for both operated and contralateral intact limbs based on kinematic analysis and inverse dynamics. The influence of graft type on knee flexion angle and moment was identified using one-way mixed (graft type and limb side) analysis of variance with post-hoc paired t-test.FindingsSignificant interaction between graft and limb was found for knee flexion and range of motion. Only the hamstring tendon group had significant kinematic deficits on the operated limb than the contralateral limb during stair ascent and descent. No significant interaction was found for knee flexion moment. Both graft groups had significant deficits in peak knee flexion moment on the operated side during stair ascent and descent.InterpretationWhile the choice of graft type does not affect the restoration of knee dynamic loading, patellar tendon graft better restores knee flexion-extension kinematics during stair ambulation.     

Trunk kinematics during locomotor activities.

We investigated upper-body (ie, trunk) angular kinematics (motions) during gait, stair climbing and descending, and rising from a chair in two reference frames--relative to the pelvis and to room coordinates. Bilateral kinematic data were collected from 11 healthy subjects (6 female, 5 male), who were 27 to 88 years of age (mean = 58.9, SD = 17.9). During stair climbing, maximum trunk flexion relative to the room was at least double that during stair descending and gait. Arising from a chair required the most trunk flexion/extension range of motion (ROM) but the least abduction/adduction and medial/lateral (internal/external) rotation. Trunk ROM during gait was small (mean less than or equal to 12 degrees) and consistent with previous literature. Trunk range of motion relative to the room during stair climbing and descending was greater than trunk ROM during gait in all planes. The pelvis and trunk rotate in the transverse plane in greater synchrony during stair descending (mean = 8.1 degrees, SD = 5.6 degrees) than during gait (mean = 12.0 degrees, SD = 4.2 degrees). For all activities, trunk frontal and sagittal ROM relative to the pelvis was greater than that relative to the room coordinates. This finding suggests that trunk/pelvis coordination may be used to reduce potentially destabilizing anti-gravity trunk motions during daily activities. We conclude that upper-body kinematics relative to both pelvis and gravity during daily activities are important to locomotor control and should be considered in future studies of patients with locomotor disabilities.     

扁平足楼梯行走的下肢表面肌电特性

目的 探究楼梯行走时扁平足下肢肌肉在运动控制中的表现。方法 2019年3月至6月,招募男性受试者20例,其中正常足10例,扁平足10例(均为左脚),运用Noraxon表面肌电系统采集平地行走、楼梯行走时左右胫骨前肌(TA)、内侧腓肠肌(MG)、外侧腓肠肌(LG)、股直肌(RF)、股二头肌(BF)表面肌电信号,分析平均幅值和积分肌电的变化。结果 上楼梯时,扁平足TA、RF、BF的平均幅值大于正常足(|t| > 2.461, P< 0.05);下楼梯时,扁平足MG的平均幅值大于正常足(t = -1.976, P< 0.05),BF的平均幅值小于正常足(t = 2.298, P< 0.05);与平地行走相比,扁平足上楼梯时TA、RF、BF的平均幅值增加(|t| > 2.257, P < 0.05),下楼梯时RF、BF的平均幅值增加(| t| > 2.630, P < 0.05)。上楼梯时,扁平足TA、MG、LG、RF和BF的积分肌电均大于正常足(| t| > 2.492, P < 0.01);下楼梯时,扁平足MG的积分肌电大于正常足( t = -5.271, P < 0.05),BF的积分肌电小于正常足( t = 2.685, P < 0.05);与平地行走相比,扁平足上楼梯时TA、MG、LG、BF的积分肌电均增大(| t| > 2.088, P < 0.05),下楼梯时TA、LG、RF的积分肌电均降低( t > 2.059, P < 0.05)。 结论 楼梯行走时,扁平足为控制关节过度外旋,肌肉出现补偿反应。     

Association of sensorimotor function with knee joint kinematics during locomotion in knee osteoarthritis

OBJECTIVE: To evaluate the relationship between quadriceps sensorimotor function (knee joint-position sense, quadriceps strength, and quadriceps onset of activity) and knee joint kinematics (knee flexion at initial contact and loading) during level walking and stair descent in a large cohort of 220 people with knee osteoarthritis. DESIGN: Cross-sectional correlational study. RESULTS: Joint-position sense correlated with knee flexion at initial contact during both tasks (r = -0.20 and -0.14, P <0.05). Strength correlated with peak loading response knee flexion during both tasks (r = 0.17 and 0.20, P < 0.05). Quadriceps onset correlated with knee flexion at initial contact during stair descent (r = 0.14, P < 0.05). Furthermore, differences in kinematic variables were observed when participants were divided into those with best and worst sensorimotor function. CONCLUSION: Impaired sensorimotor function as measured in this study is not strongly associated with altered knee joint kinematics observed in knee osteoarthritis patients during locomotion.     

Biomechanical analysis on total knee replacement patients during gait: Medial pivot or posterior stabilized design?

BackgroundTotal Knee Replacement surgery restores joint function in patients with advanced osteoarthritis. There are several prostheses available based on different mechanisms, which guarantee knee stability during Activities of Daily Living. The aim of this study is to compare ball-in-socket (or Medial Pivot) and post-cam mechanisms to detect possible differences in terms of biomechanical parameters between these two prosthesis designs and to evaluate which design is closer to physiological biomechanics.MethodsA kinematics, kinetics and electromyography lower limb analyses were performed during gait on sixty subjects: twenty with Medial Pivot prosthesis, twenty with posterior stabilized prosthesis and twenty healthy subjects to obtain a physiologic reference.FindingsTotal Knee Replacement gait pattern for both patient groups were characterized by reduced walking speed, reduced stride length and increased stance time respect to control group. Comparison between Medial Pivot and Posterior Stabilized groups showed a reduction of knee flexion and flexor moment in patients with ball-in-socket mechanism. A prolonged muscular activity of rectus femoris was observed in Medial Pivot patients compared to Posterior Stabilized and control groups.Interpretation“Stiff knee pattern” mechanism was showed for both patient groups but more enhanced in Medial Pivot patients. Even though the Posterior Stabilized design introduces the non-physiological paradoxical motion and the Medial Pivot design seems to better reproduce the physiological condylar movement as gait analysis parameters, including kinematics, kinetics and electromyographic parameters were closer to control group and, in turn, to physiological gait for the Posterior Stabilized than Medial Pivot group parameters.     

活动衬垫和固定衬垫全膝关节置换治疗膝骨性关节炎的早期临床结果比较

背景:虽然活动衬垫膝关节假体在体外的研究中显示具有更好的关节运动学表现、更低的磨损率,但是否具有更好的体内临床效果仍有争议。目的:对比观察活动衬垫型和固定衬垫型膝关节假体在置换后1年时膝关节活动度和临床效果。设计、时间及地点:回顾性病例对比分析。2003-11/2006-07首尔国立大学盆唐医院关节重建中心。对象:共纳入接受全膝关节置换488例患者669膝。244例患者341膝采用了固定衬垫型假体,244例患者328膝采用活动衬垫型假膝。方法:所有手术皆由一位固定医师(TKKim)完成。采用髌旁内侧入路,术中不翻转髌骨,而将髌骨向外侧脱位进行显露。以间隙测量器作为间隙撑开工具并进行间隙的准确测量,根据测量结果进行软组织松解平衡,直到达到下述标准:屈曲间隙大于伸直间隙不超过3.0～4.0mm或伸直间隙大于屈曲间隙不超过1.0～2.0mm,对于内翻畸形膝关节,外侧间隙大于内侧间隙2.0～3.0mm是可以接受的。常规行髌骨置换,所有假体都采用骨水泥固定。主要观察指标:以角尺测量患者置换前后膝关节屈曲挛缩程度和最大屈曲度。置换前后膝关节的疼痛和功能状态采用AKS评分、髌股关节评分、WOMAC评分和SF-36系统评分进行评价。结果:两组患者在性别、年龄、身高、体质量和体质量指数方面差异没有显著性。置换后两组在PF膝前痛评分、WOMAC疼痛评分和SF-36躯体疼痛评分方面两组差异无显著性(P>0.05);固定衬垫组平均AKS疼痛评分略高于活动衬垫组(48.5±3.2,47.5±4.8,P=0.010)。置换后两组患者的屈曲畸形得到了很好的矫正(P=0.341),两组的膝关节活动度差异没有显著性(P=0.412)。置换后所有反映膝关节功能的评价指标两组间差异均无显著性(P>0.05)。结论:活动衬垫型膝关节假体置换后在膝关节活动度、疼痛缓解以及膝关节功能方面与固定衬垫型膝关节假体相比并没有显著性优势。手术技术是获得置换后良好临床效果的关键。     

Do gait adaptations during stair climbing result in changes in implant forces in subjects with total hip replacements compared to normal subjects?

BACKGROUND: The study objective was to identify gait abnormalities and their relationships to hip loading during stair climbing after total hip replacement. Hypotheses: (1) total hip replacement subjects would have significantly lower dynamic hip range of motion and peak external moments during stair climbing compared to normal subjects and (2) the peak twisting moment about the long axis of the implant and peak hip forces would be significantly reduced in subjects with total hip replacements compared to normal subjects. METHODS: Gait parameters during a stair climbing task were measured for 15 total hip replacement subjects and 15 matched normal subjects. Forces were predicted using an analytical model. FINDINGS: The peak external adduction moment for the total hip replacement subjects was 25% less than normal (P=0.001). The external rotation moment was 26% less than normal (P=0.029) but the extension moment was 77.5% higher in the total hip subjects than in normal subjects (P=0.004). The peak twisting moment and first peak contact force were 18% and 14% lower in the total hip group compared to normal (P=0.090 and P=0.055, respectively). The second peak force was nearly equal (P=0.424) between the two groups. INTERPRETATION: Stair climbing biomechanics differ from normal in subjects with total hip replacements, however these unconscious alterations do not abnormally increase the hip loads during this activity. More work is necessary to determine exactly what constitutes optimal stair climbing biomechanics for patients with total hip replacements.     

The effect of total knee replacement on the knee varus angle and moment during walking and stair ascent

BACKGROUND: This study examined the effect of total knee replacement surgery on the frontal plane knee varus angle and moment. Secondarily, the relationships between knee varus angle and moment to a clinical outcome measure were assessed. METHODS: Twenty-one patients with total knee replacement and 21 controls performed level walking and stair ascent at two testing periods, pre- and 6-months post-surgery. The dependent variables included frontal plane knee angle and moment, and Western Ontario and McMaster Universities Osteoarthritis Index scores. FINDINGS: During level walking the mean knee varus moment of the patient group was significantly greater than controls at pre-surgery but was restored to control level post-operatively. During stair ascent the patient group produced a significantly smaller knee varus moment post-surgically. The mean frontal knee valgus angle of total knee replacement patients increased significantly from pre- to post-surgery during level walking. The Western Ontario and McMaster Universities Osteoarthritis Index score was not significantly correlated to the knee variables. However, the knee angle and moment were significantly correlated during level walking pre- and post-operatively and stair ascent post-operatively. INTERPRETATION: The decreased frontal plane knee moment in total knee replacement patients during level walking appeared to be affected by surgical realignment of the tibio-femoral joint, as the frontal knee angle and varus moment were strongly correlated. The subjective Western Ontario and McMaster Universities Osteoarthritis Index and the objective gait measures appeared to capture different dimensions of knee osteoarthritis.     

人工膝关节固定平台高屈曲假体与旋转平台高屈曲假体置换后膝关节功能的比较

背景:膝关节假体早期设计的目的是为了改善膝关节患者的严霞疼痛.随着假体设计的不断改进,已经出现了具有良好屈曲功能的高屈曲膝关节假体.目的:比较应用固定平台高屈曲假体与旋转平台高屈曲假体行全膝关节置换后临床疗效的差异.设计:以患者为研究对象的非随机化同期对照观察.对象:2006-01/12在天津市人民医院骨关节科接受全膝关节置换的34例重度骨性关节炎患者(50膝).方法:34例患者巾16例(25膝)接受固定平台高屈曲膝假体置换,所用假体为美国捷迈公司提供LPS flexion假体;18例(25膝)接受旋转平台高屈曲膝假体置换术,所用假体为美国强生公司提供PFC sigma RPF假体.主要观察指标:对患者术前、术后两周、术后1,3,6个月的膝关竹功能按HSS评分标准进行评分,并观察术后6个月膝关节屈曲度.结果:34例均完成治疗和6个月的随访.旋转平台高屈曲假体组术后2周膝关节HSS评分高于固定平台高屈曲假体组(尸<0.05),术后1,3,6个月两组膝关节HSS评分比较无显著差异(P>0.05).术后6个月膝关节屈曲度两组比较无显著差异[(130.4±15.2)°vs(129.9±13.8)°,P>0.05].结论:固定平台高屈曲假体与旋转平台高屈曲假体行全膝关节置换治疗重度膝关节骨性关节炎的早期疗效基本相同.     

Kinematic analyses during stair descent in young women with patellofemoral pain

Background

Compensatory movement strategies may develop in response to pain to avoid stress on the affected area. Patellofemoral pain is characterised by intermittent periods of pain and the present study addresses whether long-term pain leads to compensatory movement strategies that remain even when the pain is absent.

Method

Lower extremity kinematics in three dimensions was studied in stair descent in 17 women with patellofemoral and in 17 matched controls. A two-dimensional geometric model was constructed to normalise kinematic data for subjects with varying anthropometrics when negotiating stairs of fixed proportions.

Results

There were minor differences in movement patterns between groups. Knee joint angular velocity in the stance leg at foot contact was lower and the movement trajectory tended to be jerkier in the patellofemoral group. The two-dimensional model showed greater plantar flexion in the swing leg in preparation for foot placement in the patellofemoral group.

Interpretation

The results indicate that an altered stair descent strategy in the patellofemoral group may remain also in the absence of pain. The biomechanical interpretation presumes that the strategy is aimed to reduce knee joint loading by less knee joint moment and lower impact force.