Cost-benefit comparison of the Oxford Knee score and the American Knee Society score in measuring outcome of total knee arthroplasty

The American Knee Society score (AKSS) and the Oxford Knee score (OKS) are validated outcome measures for evaluation of total knee arthroplasties (TKAs). We investigated whether patient self-assessment using the OKS offers a viable alternative to clinical review using the AKSS. Preoperative, 2-year, 5-year, and 10-year postoperative OKS and AKSS were reviewed from TKA patients. The scores were analyzed using the Pearson correlation. There was good correlation of OKS and AKSS at 2 years. This implies that patient self-assessment is a viable screening tool to identify which patients require clinical review, at 2 years, after TKA. However, the moderate correlation at 5 and 10 years indicates that clinical evaluation remains necessary at these time points.     

Lateral patellar facetectomy had improved clinical results in patients with patellar-retaining total knee arthroplasty

To evaluate the functional outcome of a partial lateral facetectomy in patellar-retaining total knee arthroplasty (TKA), we retrospectively analyzed 63 knees of 59 patients who underwent TKA for primary knee osteoarthritis with (32 knees of 30 patients, group 1) or without (31 knees of 29 patients, group 2) patellar facetectomy from September 2005 to July 2007. All cases were followed up for a minimum of 36 months. Although there was no significant differences between the 2 groups in preoperative patellar score, Western Ontario and McMaster Universities score, knee and function scores, postoperatively, group 1 showed more significant improvements in the scores and fewer lateral patellar osteophytes in radiographs than group 2. A partial lateral facetectomy is an effective way to improve the function of patellar-retaining TKA in patients with primary osteoarthritis.     

Elevated Body Mass Index Is a Risk Factor for Failure to Achieve the Knee Disability and Osteoarthritis Outcome Score-Physical Function Short Form Minimal Clinically Important Difference Following Total Knee Arthroplasty

BackgroundThe aims of this study are (1) to assess the association between body mass index (BMI) and failure to achieve the 1-year Knee Disability and Osteoarthritis Outcome Score-Physical Function Short Form (KOOS-PS) minimal clinically important difference (MCID) for total knee arthroplasty (TKA) patients and (2) to determine if there is a BMI threshold beyond which the risk of failing to achieve the MCID is significantly increased.MethodsA regional arthroplasty registry was queried for TKA patients from 2016 to 2019 with completion of preoperative and 1-year postoperative KOOS-PS. The MCID threshold was derived using a distribution-based approach. Demographic and patient-reported outcome measure variables were collected. BMI was analyzed continuously and categorically using cutoffs defined by the Centers for Disease Control and Prevention. The association between failure to achieve 1-year MCID and BMI was analyzed using multiple logistic regression. A BMI threshold was determined using the Youden index and receiver operating characteristic curve.ResultsIn total, 1059 TKAs were analyzed. BMI assessed continuously was significantly associated with failure to achieve the KOOS-PS MCID (odds ratio 1.03, 95% confidence interval 1.00-1.05, P = .025). Analysis of BMI categorically revealed that “overweight” (25-30 kg/m²), “obese class I” (30-35 kg/m²), “obese class II” (35-40 kg/m²), and “obese class III” (>40 kg/m²) patients faced 77%, 76%, 83%, and 106% greater risk, respectively, of failing to achieve the KOOS-PS MCID compared to “normal BMI” (<25 kg/m²) patients.ConclusionElevated BMI was associated with an increased risk of failure to achieve the 1-year KOOS-PS MCID following TKA.     

Reliability and Validity of the Knee Injury and Osteoarthritis Outcome Score in Patients Undergoing Unicompartmental Knee Arthroplasty

BackgroundThe Knee Injury and Osteoarthritis Outcome Score (KOOS) was developed to document outcomes from knee injury, including the impact of osteoarthritis on knee function. The purpose of this study is to determine the reliability and validity of the KOOS subscales for evaluating outcomes following unicompartmental knee arthroplasty (UKA).MethodsKOOS Pain, Activities of Daily Living (ADL), Sport, Symptoms, and Quality of Life (QoL) scores collected from 172 patients who underwent UKA were used in the analysis. KOOS subscales were tested for reliability and validity of scores through a Rasch model analysis.ResultsKOOS Sport, KOOS ADL, and KOOS QoL had good evidence of reliability with acceptable person reliability, person separation, and item reliability. For overall scale functioning, KOOS Pain, Symptoms, and ADL all had 1 question that did not have an acceptable value for infit or outfit mean square value. Questions in KOOS Sport and QoL all had acceptable values. There was a positive, linear relationship between the Short-Form 12 Physical Component Summary and the KOOS subscales which indicated good evidence of convergent validity. These associations were also seen when the cohort was separated in medial and lateral UKA.ConclusionTwo of the 5 KOOS subscales (KOOS Sport and KOOS QoL) were considered adequate in measuring outcomes, as well as reliability. The KOOS ADL had borderline values; however, it had adequate infit and outfit values. The KOOS Pain and Symptom score performed poorly in this analysis. For documenting outcomes following UKA, this study supports the use of KOOS ADL, Sport, and QoL.     

Preoperative knee stiffness and total knee arthroplasty outcomes

A retrospective case-control study was conducted to evaluate 1-year total knee arthroplasty (TKA) outcomes among preoperative stiff knees, range of motion (ROM) 80° or less, compared with nonstiff preoperative knees, ROM 100° or greater. A total of 134 stiff knee cases were compared with a matched cohort of 134 non-stiff knee controls. Knee Society Score and Oxford Knee Score change scores from baseline to 1 year were similar between the groups. Stiff knees experienced a significantly greater mean improvement in ROM from baseline to 1 year (30.8° ± 18.8°) as compared with nonstiff knees (1.1° ± 12.8°) (P < .0001). Although ultimate ROM of a TKA can be restricted secondary to preoperative stiffness, improvements in outcomes and ROM are not affected. We conclude that progression of stiffness should not in and of itself lead to earlier intervention of TKA in most cases.     

全膝关节置换术中不同截骨顺序的比较

目的 比较不同截骨顺序在全膝关节置换术中应用的临床效果.方法 对40例患者40膝行全膝关节置换术,根据不同截骨顺序分成2组:观察组20膝,先行股骨截骨;对照组20膝,先行胫骨截骨.比较两组手术时间、术后引流量、术前术后膝关节功能情况及HSS评分,并进行统计学分析.结果 40例患者均获得随访,时间3～14个月.手术时间和术后引流量:观察组分别为(52.1±14.3)min和(324±46)ml;对照组分别为(75.5±16.7)min和(416±50)ml,差异有统计学意义(P<0.01).术后6周和12周的膝关节活动度:观察组分别为87.5°±13.1°和100.5°±8.2°;对照组分别为86.6°±14.7°和101.3°±6.2°,差异无统计学意义(P>0.05).术后6周和12周的HSS评分:观察组分别为(89.43±9.6)分和(91.72±7.6)分;对照组分别为(89.95±8.9)分和(90.87±8.5)分,差异无统计学意义(P>0.05).结论 全膝关节置换术先行股骨截骨可以为胫骨的操作获得更大的操作空间,手术操作简便,可以缩短手术时间,减少失血量.     

Early clinical outcome and learning curve following unilateral primary total knee arthroplasty after introduction of a novel total knee arthroplasty system

BACKGROUND New implants for total knee arthroplasty(TKA) are continuously introduced with the proposed benefit of increased performance and improved outcome. Little information exists on how the introduction of a novel arthroplasty implant affects the perioperative and surgical outcome immediately after implementation.AIM To investigate how surgery-related factors and implant positioning were affected by the introduction of a novel TKA system.METHODS A novel TKA system was introduced at our institution on 30 th November 2015. Seventy-five TKAs performed with the Persona TKA immediately following its introduction by 3 different surgeons(25 TKAs/surgeon) were identified as the Introduction Group. Moreover, the latest 25 TKAs performed by each surgeon prior to introduction of the Persona TKA were identified as the Control Group. A Follow-up Group of 25 TKAs/surgeon was identified starting 1-year after the end of the introduction period. Demographics, surgery-related factors and alignment data were recorded, and intergroup differences compared.RESULTS Following introduction of the novel implant, Persona TKA was utilized in 69%(71%), 53%(54%), and 45%(75%) of primary TKA procedures by the three surgeons, respectively(Follow-up Group). Mean surgery time was increased by 28%(P 0.0001) and mean intra-operative blood loss by 25%(P = 0.002) in the Introduction Group, while only the mean surgery time was increased in the Follow-up Group by 18%(P 0.0001). Overall alignment was similar between the groups apart from femoral flexion(FF) and tibial slope(TS). The number of FF outliers was reduced in the Introduction Group with a more pronounced decrease in the Follow-up Group.CONCLUSION Introduction of the new TKA implant increased surgical time and intraoperative blood loss immediately after its introduction. These differences diminished one year after introduction of the new implant. Fewer outliers with respect to FF and TS were seen when using the novel TKA implant. Further studies are needed to investigate if these differences persist over time and correlate with patient reported outcomes.     

膝表面置换术在类风湿性膝关节炎和骨性膝关节炎的应用和比较

目的探讨膝关节表面置换术治疗类膝关节风湿性关节炎(RA)和膝关节骨性关节炎(OA)的临床疗效、安全性差异。方法自2010-01—2012-04采用膝关节表面置换术治疗68例(84膝)膝关节疾患,按照疾病类型分为OA组和RA组,对比分析2组手术时间、术中出血量、VAS评分、切口愈合时间、HSS单项评分及总分等。结果术后68例(84膝)获得平均47个月随访,随访期间无人工膝关节假体脱位。OA组手术时间、术中失血量、术后引流量及VAS评分显著低于RA组,差异有统计学意义(P0.05)。OA组术后1个月疼痛和HSS总分显著高于RA组,差异有统计学意义(P0.05),OA组术后1年和3年疼痛、功能、活动范围单项评分和HSS总分均显著高于RA组,差异有统计学意义(P0.05)。结论OA及RA人工全膝置换术后功能均有一定改善,与OA相比,RA患者术后近中期疗效相对较差,但远期疗效差异有待进一步研究。     

滑膜切除对全膝关节置换术治疗骨性关节炎临床效果的影响

目的探讨滑膜切除对全膝关节置换术治疗骨性关节炎临床效果的影响。方法回顾性分析自2011-07—2014-12诊治的105例膝关节骨性关节炎,分为试验组和对照组,试验组(56例)行膝关节置换术与滑膜切除术,对照组(49例)只行膝关节置换术。记录并比较2组手术时间、术后引流量、隐性失血量、输血率及住院时间等,术前和术后随访时进行VAS评分、KSS评分及测量关节活动度。结果试验组获得随访(17.0±4.2)个月,对照组获得随访(15.0±3.1)个月。试验组手术时间、隐性失血量、术后引流量较对照组多,差异均有统计学意义(P0.05),2组住院时间及输血率差异无统计学意义(P0.05)。2组术后4周及1年随访时VAS评分、KSS临床评分、KSS功能评分差异无统计学意义(P0.05)。2组术后3 d及术后7 d关节活动度比较差异无统计学意义(P0.05)。结论与单纯行膝关节置换术相比,膝关节置换同时行滑膜切除术在治疗骨性关节炎上无优势,然而行滑膜切除术会导致更多的体内失血,延长手术时间,从而增加了手术风险。     

混合型单髁与全膝关节置换治疗膝内侧间室骨关节炎的疗效比较

目的：探讨Oxford第3代混合型单髁置换（unicompartmental knee arthroplasty,UKA）与全膝关节置换（total knee arthroplasty,TKA）治疗膝关节内侧间室骨关节炎的疗效。方法：回顾性分析2017年10月至2019年10月行膝关节置换术的156例患者,男44例,女112例,年龄50~75（58.76±4.97）岁。根据不同治疗方式分为单侧TKA组和单侧Oxford第3代混合型UKA组。单侧TKA 81例（81膝）,男23例,女58例,年龄51~75（58.60±5.01）岁;单侧Oxford第3代混合型UKA 75例（75膝）,男21例,女54例,年龄50~72（58.92±4.95）岁。比较两组临床评估指标,包括手术一般情况、相关并发症、美国膝关节协会评分（American Knee Society score,AKSS）临床评分和功能评分;影像评估指标包括髋膝踝角（hip-knee-ankle angle,HKA）、股骨假体内外翻角（femoral component valgus/varus angle,FCVA）、股骨假体后倾角（femoral component posterior slope angle,FCPSA）、胫骨假体内外翻角（tibial component valgus/varus angle,TCVA）、胫骨假体后倾角（tibial component posterior slope angle,TCPSA）,是否发生膝关节外侧间室进展、衬垫脱位、假体下沉、松动。结果：UKA组术中出血量、手术时间、住院天数均显著优于TKA组（P<0.05）,两组术后均未出现并发症。两组患者均获随访,时间24~54（38.01±8.90）个月。末次随访两组AKSS临床评分、功能评分、HKA均优于术前（P<0.05）。末次随访UKA组AKSS临床评分、功能评分均优于TKA组（P<0.05）,TKA组HKA优于UKA组（P<0.05）。末次随访两组TCVA、FCVA差异无统计学意义（P>0.05）,UKA组TCPSA、FCPSA大于TKA组（P<0.05）,UKA组未出现外侧室进展。结论：Oxford第3代混合型UKA治疗膝关节内侧间室骨关节炎,较TKA具有手术创伤小、失血量少、手术时间短、住院时间短、术后快速康复、膝关节功能恢复更好等优势,疗效满意。     

全膝关节置换术后严重异位骨化与关节僵硬

[目的]探讨全膝关节置换术后严重异位骨化与关节僵硬的关系。[方法]对420例接受全膝关节置换术的患者随访,其中9例出现了Ⅲ级异位骨化,分别测量并记录该9例患者术后2周、12个月的疼痛评分和膝关节活动度,拍摄X线片,测量异位骨的大小。随机抽取9例无异位骨化的关节置换术后患者作为对照组,并测量疼痛评分及活动度。分别将异位骨化组和对照组的结果进行对比。[结果]关节置换术后Ⅲ级异位骨化的发病率为2.1%,X线片显示异位骨>5 cm,侵及股四头肌,引起关节疼痛。异位骨化组术后2周疼痛评分平均25.6分,关节最大伸直角度平均1.1°,最大屈曲角度119.1°,与对照组比较差异均无统计学意义(P>0.05)。异位骨化组术后12个月疼痛评分平均15.56分,低于术后2周(P<0.01),与对照组术后12个月(25分)比较有显著差异(P<0.01)。关节活动度:伸直6.1°,屈曲91.7°与术后2周和对照组术后12个月比较均有显著差异(P<0.01)。[结论]全膝关节置换术后Ⅲ级异位骨化可以导致关节疼痛和活动度受限,是术后关节僵硬的原因之一,严重影响置换术后临床效果。     

Bilateral staged total knee arthroplasty in obese patients

Introduction The purpose of this study was to compare the clinical and functional results and complications associated with staged bilateral total knee arthroplasty (TKA) performed 4–11 days apart during a single hospitalization in patients who were obese and patients who were not obese. Methods We retrospectively evaluated 48 (96 knees) patients who were obese and divided into two groups based on their body mass indices (BMI). Morbidly obese patients (group A1, BMI ≥ 40 kg/m²) consisted of 21 patients (42 knees), and obese patients (group A2, BMI ≥ 30 kg/m²) consisted of 27 patients (54 knees). The control group (group B, BMI < 30 kg/m²) consisted of 20 non-obese patients (40 knees), who were undergoing staged bilateral procedure within the same time frame. All patients had cemented TKAs with use of posterior cruciate sparing prosthesis without patellar resurfacing. If medically stable after the first arthroplasty the patients then underwent the second arthroplasty 4–11 days later. The data on major complications and minor complications were evaluated. Results Although, there was no statistically significant difference in overall complication rates in any of the groups, the non-obese group had fewer wound complications than the other groups (P > 0.05). No significant differences in preoperative or postoperative Knee Society score, and functional score could be demonstrated between the three groups (P > 0.05). Both obese and nonobese patients showed improvements in pain and function from pre-surgery to a minimum 2 years follow-up. Conclusion Results of bilateral staged TKAs in obese patients have low complication and high success rates and increased BMI has no negative effect on the early outcome. Bilateral staged TKA might be a good treatment alternative for the improvement of the patient’s quality of life and functional and clinical outcomes.     

不同程度膝内翻患者初次全膝关节置换术后下肢力线分布与近期临床疗效的关系

目的:探讨不同程度膝内翻畸形患者行初次全膝关节置换术后下肢力线分布与近期临床疗效之间的关系。方法:自2016年12月至2018年3月行初次全膝关节置换术治疗的膝骨性关节炎患者87例(101膝),男21例(25膝),女66例(76膝);年龄51～85(67.6±7.0)岁。根据患者全膝关节置换术后下肢髋膝踝角(hip knee ankle angle,HKA)不同分为4组:中立位组(A组),-3°≤HKA≤3°,50膝;轻度内翻组(B组),3°相似文献   

出院准备服务在全膝关节置换术病人中的应用

目的 探讨出院准备服务在全膝关节置换术（total knee arthroplasty, TKA）病人中的临床护理效果及意义。方法 将2018年1月至6月我科收治的58例单侧TKA病人纳入对照组,采用常规护理和健康教育;将2018年7月至12月收治的64例单侧TKA病人纳入观察组,在常规护理和健康教育的基础上提供出院准备服务。术前和术后3个月采用美国特种外科医院（Hospital for Special Surgery, HSS）膝关节功能评分标准和健康调查简表（the MOS item short form health survey, SF-36）评价病人膝关节功能和生活质量,出院时调查病人护理服务满意度。结果 术后3个月,观察组HSS膝关节功能评分为（89.56±7.17）分,优于对照组的（77.59±6.03）分,差异有统计学意义（t=9.030,P=0.007）;观察组SF-36评分为（68.29±8.68）分,优于对照组的（51.29±3.55）分,差异有统计学意义（t=5.060,P=0.014）。出院时,观察组护理服务满意度为96.88%（62/64）,明显高于对照组的86.21%（50/58）,差异有统计学意义（χ²=3.920,P=0.012）。结论 实施出院准备服务全面、有效地保证了TKA病人出院后康复训练的连续性,使病人及时、准确地获得膝关节功能锻炼指导,提升了TKA病人的膝关节功能、生活质量和护理服务满意度。     

Factors predicting patient satisfaction 2 years after total knee arthroplasty for osteoarthritis

Objective

To identify factors predicting patient satisfaction 2 years after total knee arthroplasty (TKA) for osteoarthritis.

Methods

Prospective multicenter study of patients followed up for 2 years after TKA for osteoarthritis. We evaluated pain and function (Lequesne index and WOMAC) at baseline and after 2 years. After 2 years, the patients rated their satisfaction as a percentage, with values greater than 50% defining good satisfaction. Factors associated with good satisfaction were identified by univariate analyses followed by multivariate analysis.

Results

Of 299 patients, 264 completed the study (26 were lost to follow-up, six died, and three refused the 2-year evaluation), including 237 (89.8%) with satisfaction scores greater than 50%. Highly significant improvements were found after 2 years versus baseline in the Lequesne index (7.9 vs. 14.5, P < 0.0001) and WOMAC index (26.3 vs. 51.3, P < 0.0001). There were 26 (9.8%) complications. Factors significantly associated with good satisfaction in the multivariate model were absence of complications (P = 0.004), body mass index less than 27 kg/m² (P = 0.015), high radiological joint narrowing score (P = 0.038), age greater or equal to 70 years (P = 0.038), and absence of depression at the 2-year evaluation (P = 0.002).

Conclusion

We report the first prospective multicenter study done in France to assess pain and function in a large number of patients treated with TKA for osteoarthritis. Our results indicate a high success rate. We identified three factors that predict patient satisfaction and can be assessed before surgery (age greater than 70 years, absence of obesity, and severe joint space narrowing).     

洛索洛芬在全膝关节置换的围手术期镇痛与术后镇痛中的研究

目的分析洛索洛芬钠片剂对于全膝关节置换（TKA）术后短期临床效果的影响。方法 2009年1月至2009年12月因膝骨关节炎行单侧全膝关节置换手术患者197例,其中围手术期使用镇痛药物为洛索洛芬和（或）阿片类药物的患者84例。仅使用阿片类药物镇痛的患者为对照组,共27例（男9例,女18例）;仅术后使用洛索洛芬镇痛的患者为POST组,共31例（男9例,女22例）;术前和术后均使用洛索洛芬的患者为PERI组,共26例（男7例,女19例）。结果三组患者在平均年龄、体重指数、术前患病时间、术前疼痛评分、术前膝关节活动度、术前HSS评分、手术时间、术中止血带时间、术后引流量、术后2周疼痛评分、术后2周活动度、术后2周HSS评分及术后2周行走距离等指标方面无显著差异。但POST组和PERI组阿片类药物使用时长均短于对照组,阿片类药物末次使用时间也早于对照组（P〈0.05）。与POST组相比,PERI组洛索洛芬用药总量略少,但无统计学显著意义。结论洛索洛芬联合阿片类药物可有效地控制TKA术后疼痛,达到满意的临床效果。联合用药可减少阿片类药物的用量、缩短阿片类药物的使用时间。洛索洛芬围术期镇痛与术后镇痛相比具有基本相同的临床镇痛效果,但前者的用药量略少。     

Study on the correlation between early three-dimensional gait analysis and clinical efficacy after robot-assisted total knee arthroplasty

PurposeRobot-assisted technology is a forefront of surgical innovation that improves the accuracy of total knee arthroplasty (TKA). But whether the accuracy of surgery can improve the clinical efficacy still needs further research. The purpose of this study is to perform three-dimensional (3D) analysis in the early postoperative period of patients who received robot-assisted total knee arthroplasty (RATKA), and to study the trend of changes in gait parameters after RATKA and the correlation with the early clinical efficacy.MethodsPatients who received RATKA in the Center of Joint Surgery, the First Hospital Affiliated to Army Military Medical University from October 2020 to January 2021 were included. The imaging parameters, i.e., hip-knee-ankle angle, lateral distal femoral angle, medial proximal tibial angle, posterior condylar angle were measured 3 months post-TKA. The 3D gait analysis and clinical efficacy by Western Ontario Mac Master University Index (WOMAC) score were performed pre-TKA, 3 and 6 months post-TKA. The differences in spatiotemporal parameters of gait, kinetic parameters, and kinematic parameters of the operated limb and the contralateral limb were compared. The correlation between gait parameters and WOMAC scores was analyzed. Paired sample t-test and Wilcoxon rank-sum test were used to analyze the difference between groups, and Spearman correlation coefficient was used to analyze the correlation.ResultsThere were 31 patients included in this study, and the imaging indexes showed that all of them returned to normal post-TKA. The WOMAC score at 3 months post-TKA was significantly lower than that pre-TKA, and there was no significant difference between at 3 and 6 months. The 3D gait analysis results showed that the double support time of the operated limb reduced at 3 and 6 months (all p < 0.05), the maximum extension and maximum external rotation of the knee joint increased at stance phase, and the maximum flexion angle, the range of motion and the maximum external rotation increased at swing phase. Compared with the preoperative data, there were significant improvements (all p < 0.05). Compared with the contralateral knee joint, the maximum external rotation of the knee joint at swing phase was smaller than that of the contralateral side, and the maximum flexion and extension moment was greater than that of the contralateral knee. The maximum external rotation moment of the joint was greater than that of the contralateral knee joint (p < 0.05). There was a negative correlation between the single support time pre-TKA and the WOMAC score at 3 months (p = 0.017), and the single support time at 3 months was negatively correlated with the WOMAC score at 6 months (p = 0.043). The cadence at 6 months was negatively correlated with the WOMAC score at 6 months (p = 0.031). The maximum knee extension at stance phase at 6 months was negatively correlated with the WOMAC score at 6 month (p = 0.048). The maximum external rotation at stance phase at 6 months was negatively correlated with the WOMAC score at 6 months (p = 0.024).ConclusionThe 3D gait analysis of RATKA patients is more sensitive than WOMAC score in evaluating the clinical efficacy. Trend of changes in gait parameters shows that the knee joint support, flexion and extension function, range of motion, external rotation and varus deformity moment of the patient were significantly improved at 3 months after surgery, and continued to 6 months after surgery. Compared with the contralateral knee, the gait parameters of the operated limb still has significant gaps in functionality, such as the external rotation and flexion and extension. The single support time, cadence, knee extension, and knee external rotation of the operated limb have a greater correlation with the postoperative WOMAC score. Postoperative rehabilitation exercises should be emphasized, which is of great value for improving the early efficacy of RATKA.     

Surgical factors for total knee arthroplasty in younger patients

With improvements in implant modularity and polyethylene, it is important to assess the contemporary performance of cement vs. cementless fixation in total knee arthroplasty (TKA). Aseptic loosening is the most common indication for revision. Registry data indicates that the type of fixation (cemented, cementless, or hybrid) makes little difference in revision rates for younger patients (<55 years old). Regardless of the type of fixation, there is an opportunity for improvement. Attention to surgical factors, such as coronal alignment and cementing technique, can improve the survivorship of TKA.     

Coronal laxity in extension in vivo after total knee arthroplasty

We performed stress arthrometric studies on 77 knees (71 patients) with total knee arthroplasty to determine the presence and magnitude of femoral abduction and adduction in knee extension. A total of 53 knees (49 patients) had posterior cruciate ligament-retaining (PCLR) prostheses, and 24 (22 patients) had PCL-substituting (PCLS) prostheses. The selected patients had successful arthroplasties with no clinical complications a minimum of 5 years after primary surgery. Each patient was subjected to a successive abduction and adduction stress test at 0°–20° of flexion using a Telos arthrometer. The mean values for abduction and adduction were 4.8° and 4.5° with a PCLR prosthesis, respectively, and 4.6° and 4.0° with a PCLS prosthesis. There were no statistical differences between PCLR and PCLS knees. The results suggest that approximately 4° of laxity in these directions is suitable in total knee arthroplasty for a satisfactory clinical outcome 5–9 years after surgery.