全膝关节置换术后下肢绝对长度的变化模式

目的探讨全膝关节置换术(total knee arthroplasty,TKA)术后下肢绝对长度的变化模式。方法前瞻性分析2014年1月至2017年12月56例行全膝关节置换术治疗终末期骨关节炎患者的临床资料,其中男14例,女42例;年龄为56-82岁,平均为(71.6±2.4)岁。根据术前内翻的程度将患者分为两组,内翻畸形<5°为A组,10°≥内翻畸形≥5°为B组,每组28例。术中在股骨前侧和胫骨前侧分别做标记,记录截骨前膝关节完全伸直位和安装假体后膝关节完全伸直位,分别测量截骨前及假体安装后两标记点之间的距离,两次距离的差值就是下肢绝对长度的变化值。术前及术后记录两组的下肢负重位全长X线的机械力线、膝关节活动范围、美国膝关节协会评分(knee society score,KSS)和功能评分,同时记录术后患者的满意率和对肢体长度变化的感知率。TKA术前A组膝关节活动范围(78.5±30.2)°,KSS评分(64.8±11.6)分,功能评分(62.8±9.8)分,机械轴线平均内翻(3.8±1.2)°;B组膝关节活动范围(76.4±31.4)°,KSS评分(63.4±10.4)分,功能评分(60.6±9.6)分,机械轴线平均内翻(7.4±2.3)°。结果 56例患者均获随访,随访时间6-40个月,平均(18.4±4.6)个月。所有患者未出现感染及假体松动。术后6个月时,A组膝关节活动范围(96.4±28.4)°,KSS评分(86.2±10.4)分,功能评分(83.6±9.6)分,机械轴线平均内翻(1.6±1.1)°;B组膝关节活动范围(94.6±26.6)°,KSS评分(84.8±10.2)分,功能评分(86.2±9.2)分,机械轴线平均内翻(1.8±1.2)°。两组均较术前明显改善,差异有统计学意义(P<0.05)。两组术后KSS及功能评分比较,差异无统计学意义(P>0.05)。总体来说,82.1%(46/56)的患者术后肢体绝对长度增加,其中A组为71.4%(20/28),B组为92.9%(26/28),差异有统计学意义(P<0.05)。术后能感知肢体长度有变化的患者约50.0%(28/56),其中A组为35.7%(10/28),B组为64.3%(18/28),差异有统计学意义(P<0.05)。因感觉肢体长度变化而不满意的患者约为24.2%。术后半年,感知肢体长度有变化的患者下降为14.3%(8/56),其中A组为10.7%(3/28),B组为17.9%(5/28),差异无统计学意义(P>0.05)。因感觉肢体长度有变化而不满意的患者下降为3.6%(2/56)。结论应用TKA治疗晚期骨关节炎,可明显改善功能,缓解疼痛,恢复肢体的下肢力线。但是,大多数患者置换术后肢体绝对长度会发生变化,而且这种变化的幅度和术前膝关节内翻的程度相关。术后部分患者会对这种变化有明显的感知,进而可能影响治疗总体的满意率。     

Association Between Body Mass Index and Thirty-Day Complications After Total Knee Arthroplasty

Background

Although previous studies have evaluated the effect of obesity on the outcomes of total knee arthroplasty (TKA), most considered obesity as a binary variable. It is important to compare different weight categories and consider body mass index (BMI) as a continuous variable to understand the effects of obesity across the entire range of BMI. Therefore, the objective of this study is to analyze the effect of BMI on 30-day readmissions and complications after TKA, considering BMI as both a categorical and a continuous variable.

Impact of Body Mass Index on Functional Performance After Total Knee Arthroplasty

The purpose of this investigation was to determine whether functional performance and self-report outcomes are related to body mass index (BMI) after total knee arthroplasty (TKA). We hypothesized that higher BMIs would negatively affect functional performance as assessed by the timed up-and-go test, stair climbing test, 6-minute walk test, and self-report questionnaires. A total of 140 patients with BMIs ranging from 21.2 to 40.0 kg/m² were followed over the first 6 months after unilateral TKA. Hierarchical linear regression was used to evaluate the impact of BMI on functional performance at 1, 3, and 6 months after TKA, while taking into account preoperative functional performance. There were no meaningful relationships between BMI and functional performance in the subacute (1 and 3 months) and intermediate (6-month) stages of recovery.     

Change in Body Mass Index After Total Knee Arthroplasty and Its Influence on Functional Outcome

Background

There is often an assumption by patients that weight loss will occur once their knee pain is relieved by total knee arthroplasty (TKA). This study aims to evaluate (1) the change in patients' body mass index (BMI) after TKA; (2) if postoperative change in BMI influences functional outcome and survival rate of TKA; and (3) the predictive factors associated with change in BMI.

Proximal Femoral Shape Changes the Risk of a Leg Length Discrepancy After Primary Total Hip Arthroplasty

Background

To evaluate how canal morphology affects the technical aspects of total hip arthroplasty, we investigated the effects of femoral cortical index (FCI) on the re-establishment of leg length at the conclusion of surgery.

Change in Body Mass Index after Simultaneous Bilateral Total Knee Arthroplasty: Risk Factors and Its Influence on Functional Outcomes

BackgroundPrevious studies evaluating weight changes following total knee arthroplasty (TKA) were performed on heterogenous cohorts. However, no study has evaluated weight changes in a cohort of simultaneous-bilateral TKA (SB-TKA) patients. This study aimed to evaluate the prevalence of patients who lost or gained weight, determine if postoperative weight change influences functional outcome, and identify predictors of weight change after SB-TKA.MethodsProspectively collected registry data of 560 patients who underwent SB-TKA were reviewed. Patients were assessed preoperatively, at 6 months, and 2 years using the Knee Society Score, Oxford Knee Score, Short-Form 36, and range of motion. Change in body mass index (BMI) >5% was used to categorize patients into 3 groups: lost, maintained, or gained weight. Analysis of variance, Kruskal-Wallis test, and chi-squared test were used to compare functional outcomes between groups. Multivariable logistic regression evaluated predictors for postoperative weight changes.ResultsAt 2 years, 59% of patients maintained weight, 28% of patients gained weight, and 13% of patients lost weight. All groups experienced similar improvements in functional outcomes, rates of minimal clinically important difference attainment, and patient satisfaction (P > .05). Older patients were more likely to gain weight (P < .05). Patients with higher preoperative BMI were more likely to gain weight (P < .05) and less likely to lose weight (P < .05). Patients with greater preoperative comorbidities were less likely to lose weight (P < .05).ConclusionUp to 41% of patients experience significant weight changes after SB-TKA. Older patients with higher preoperative BMI were more likely to gain weight, while higher preoperative BMI with more comorbidities were less likely to lose weight following SB-TKA; however, postoperative weight changes do not appear to affect functional outcomes.Level of EvidenceIII, therapeutic study.     

Body Mass Index and the Impact on Hospital Resource Use in Patients Undergoing Total Knee Arthroplasty

We identified all total knee arthroplasty patients between 1996 and 2004 and classified them by preoperative body mass index (BMI) as normal (BMI, 18.5-24.9 kg/m²), overweight (BMI, 25.0-29.9 kg/m²), obese (30-34.9 kg/m²), or morbidly obese (≥ 35.0 kg/m²). Of 5521 patients, 769 had a normal BMI, 1938 were overweight, 1539 were obese, and 1275 were morbidly obese. Adjusted length of stay was no different between normal (4.85 days), overweight (4.84 days), obese (4.86 days), or morbidly obese patients (4.93 days) (P = .30). Overall costs were similar among normal ($15?386), overweight ($15?430), obese ($15?646), or morbidly obese patients ($15?752) (P = .24). Postsurgical costs were no different among normal ($9860), overweight ($9889), obese ($10?063), or morbidly obese patients ($10?136) (P = .44). Our results suggest that increased BMI does not lead to increased hospital resource use for total knee arthroplasty.     

Influence of Body Mass Index on Sagittal Knee Range of Motion and Gait Speed Recovery 1-Year After Total Knee Arthroplasty

Background

The purpose of this prospective study was to investigate the influence of body mass index (BMI) on gait parameters preoperatively and 1 year after total knee arthroplasty (TKA).

Higher Body Mass Index Is Not Associated With Worse Pain Outcomes After Primary or Revision Total Knee Arthroplasty

We assessed whether higher body mass index (BMI) is associated with higher risk of moderate-severe knee pain 2 and 5 years after primary or revision total knee arthroplasty (TKA). We adjusted for sex, age, comorbidity, operative diagnosis, and implant fixation in multivariable logistic regression. Body mass index (reference, <25 kg/m²) was not associated with moderate-severe knee pain at 2 years postprimary TKA (odds ratio [95% confidence interval], 25-29.9, 1.02 [0.75-1.39], P = .90; 30-34.9, 0.93 [0.65-1.34], P = .71; 35-39.9, 1.16 [0.77-1.74], P = .47; ≥40, 1.09 [0.69-1.73], [all P values ≥ .47]). Similarly, BMI was not associated with moderate-severe pain at 5-year primary TKA and at 2-year and 5-year revision TKA follow-up. Lack of association of higher BMI with poor pain outcomes post-TKA implies that TKA should not be denied to obese patients for fear of suboptimal outcomes.     

Body Mass Index,American Society of Anesthesiologists Score,and Elixhauser Comorbidity Index Predict Cost and Delay of Care During Total Knee Arthroplasty

BackgroundBody mass index (BMI), American Society of Anesthesiologists (ASA) score, and Elixhauser Comorbidity Index are measures that are utilized to predict perioperative outcomes, though little is known about their comparative predictive effects. We analyzed the effects of these indices on costs, operating room (OR) time, and length of stay (LOS) with the hypothesis that they would have a differential influence on each outcome variable.MethodsA retrospective review of the institutional database was completed on primary TKA patients from 2015 to 2018. Univariable and multivariable models were constructed to evaluate the strength of BMI, ASA, and Elixhauser comorbidities for predicting changes to total hospital and surgical costs, OR time, and LOS.ResultsIn total, 1313 patients were included. ASA score was independently predictive of all outcome variables (OR time, LOS, total hospital and surgical costs). BMI, however, was associated with intraoperative resource utilization through time and cost, but only remained predictive of OR time in an adjusted model. Total Elixhauser comorbidities were independently predictive of LOS and total hospital cost incurred outside of the operative theater, though they were not predictive of intraoperative resource consumption.ConclusionAlthough ASA, BMI, and Elixhauser comorbidities have the potential to impact outcomes and cost, there are important differences in their predictive nature. Although BMI is independently predictive of intraoperative resource utilization, other measures like Elixhauser and ASA score were more indicative of cost outside of the OR and LOS. These data highlight the differing impact of BMI, ASA, and patient comorbidities in impacting cost and time consumption throughout perioperative care.     

Total Hip Arthroplasty in Patients With Multifactorial Perceived Limb Length Discrepancy

Background

Patients with advanced hip arthritis can present with multifactorial limb length discrepancies (LLDs) owing to bony shortening from growth arrest, proximal hip migration, soft-tissue contractures, and pelvic obliquity. The patient perceives an LLD that is a combination of true LLD and apparent LLD.

Effect of Body Mass Index on Digital Templating for Total Hip Arthroplasty

Background

Digital templating is becoming more prevalent in orthopedics. Recent investigations report high accuracy using digital templating in total hip arthroplasty (THA); however, the effect of body mass index (BMI) on templating accuracy is not well described.

Knee Arthrodesis as Limb Salvage for Complex Failures of Total Knee Arthroplasty

Patients with multiple failures of total knee arthroplasty (TKA) are challenging limb salvage cases. Twenty one patients over the last 10 years were referred to our service for knee fusion by arthroplasty surgeons who felt they were not candidates for revision TKA. Active infection was present in 76.2% and total bone loss averaged 6.6 cm. Lengthening was performed in 7/22 patients. Total time in Ilizarov frames was 9 months, with 93.3% union. Patients treated with IM fusion nails had 100% union. Average LLD increased from 3.6 to 4.5 cm following intervention, while those with concurrent lengthening improved to 1.6 cm. Findings suggest that bone loss and the soft-tissue envelope dictate knee fusion method, and multiple techniques may be needed. A treatment algorithm is presented.     

A Novel Method for Stratification of 30-Day Major Complication Risk Using Body Mass Index Thresholds for Patients Undergoing Total Knee Arthroplasty: A National Cohort of 443,157 Patients

BackgroundMany organizations have used pre-established body mass index (BMI) cut-offs to guide surgical decision-making. As there have been many improvements in patient optimization, surgical technique, and perioperative care over time, it is important to reassess these thresholds and contextualize them to total knee arthroplasty (TKA). The purpose of this study was to calculate data-driven BMI thresholds that predict significant differences in risk of 30-day major complications following TKA.MethodsPatients who underwent primary TKA from 2010 to 2020 were identified in a national database. Stratum-specific likelihood ratio (SSLR) methodology was used to determine data-driven BMI thresholds at which the risk of 30-day major complications increased significantly. These BMI thresholds were tested using multivariable logistic regression analyses. A total of 443,157 patients were included, who had a mean age of 67 years (range, 18 to 89 years), mean BMI of 33 (range 19 to 59), and 11,766 (2.7%) patients had a 30-day major complication.ResultsSSLR analysis identified four BMI thresholds that were associated with significant differences in 30-day major complications: 19 to 33, 34 to 38, 39 to 50, and 51+. When compared to those who had a BMI between 19 and 33, the odds of sustaining a major complication sequentially and significantly increased by 1.1, 1.3, and 2.1 times (P < .05 for all) for the other thresholds.ConclusionThis study identified four data-driven BMI strata using SSLR analysis that were associated with significant differences in the risk of 30-day major complications following TKA. These strata can be used to guide shared decision-making in patients undergoing TKA.     

Outcomes of a First Total Knee Arthroplasty Are Associated With Outcomes of the Subsequent Contralateral Total Knee Arthroplasty

BackgroundTo determine if preoperative characteristics and postoperative outcomes of a first total knee arthroplasty (TKA) were predictive of characteristics and outcomes of the subsequent contralateral TKA in the same patient.MethodsRetrospective administrative claims data from (SPARCS) database were analyzed for patients who underwent sequential TKAs from September 2015 to September 2017 (n = 5,331). Hierarchical multivariable Poisson regression (length of stay [LOS]) and multivariable logistic regression (all other outcomes), controlling for sex, age, and Elixhauser comorbidity scores were performed.ResultsThe cohort comprised 65% women, with an average age of 66 years and an average duration of 7.3 months between surgeries (SD: 4.7 months). LOS was significantly shorter for the second TKA (2.6 days) than for the first TKA (2.8 days; P < .001). Patients discharged to a facility after their first TKA had a probability of 76% of discharge to facility after the second TKA and were significantly more likely to be discharged to a facility compared with those discharged home after the first TKA (odds ratio [OR]: 63.7; 95% confidence interval [CI]: 52.1-77.8). The probability of a readmission at 30 and 90 days for the second TKA if the patient was readmitted for the first TKA was 1.0% (OR: 3.70; 95% CI: 0.98-14.0) and 6.4% (OR: 9; 95% CI: 5.1-16.0), respectively. Patients with complications after their first TKA had a 27% probability of a complication after the second TKA compared with a 1.6% probability if there was no complication during the first TKA (OR: 14.6; 95% CI: 7.8.1-27.2).ConclusionThe LOS, discharge disposition, 90-day readmission rate, and complication rate for a second contralateral TKA are strongly associated with the patient’s first TKA experience. The second surgery was found to be associated with an overall shorter LOS, fewer readmissions, and higher likelihood of home discharge.Level of EvidenceLevel 3-retrospective cohort study.     

Incidence of Leg-Length Discrepancy After Index Hinge Total Knee Arthroplasty

BackgroundLeg-length discrepancies are not commonly associated with total knee arthroplasty (TKA); however, hinge TKA is a complex form of knee reconstruction where functionality of all knee ligaments is replaced by the TKA construct. The purpose of this study is to evaluate the incidence of leg-length discrepancies after unilateral index hinge TKA and association with patient outcomes.MethodsA retrospective review was performed of all patients who underwent unilateral index hinge TKA at a single academic institution from 1999 to 2019. Among 671 patients who underwent index hinge TKA, 188 (28%) had full-length standing anteroposterior hip-to-ankle radiographs available for review both preoperatively and postoperatively. All patients with a leg-length change ≥2 cm were also contacted with a standardized questionnaire to assess for complications. The mean age was 65 years, the mean body mass index was 33 kg/m², and 52% were female. The mean number of prior surgeries was 2 (range, 0-12).ResultsThe absolute mean and median change in leg lengths was 20 mm and 13 mm, respectively (range, 0-130 mm). Lengthening occurred in 119 (63%) patients compared with shortening in 69 (37%) patients. An absolute change in leg lengths ≥1 cm was observed in 109 (58%) patients, ≥2 cm in 63 (34%) patients, and ≥5 cm in 15 (8%) patients.ConclusionLarge changes in the leg length are common after hinge TKA, likely secondary to altered soft-tissue constraints. Surgeons should be cognizant of potential changes in the leg length in the setting of hinge TKA and incorporate this into preoperative planning and patient counseling.Level of EvidenceLevel IV, therapeutic.     

Body Mass Index as Predictor of Health-Related Quality-of-Life Changes After Total Hip Arthroplasty: A Cross-Over Study

The objective of this study was to examine the contribution of patient weight and other preoperative variables to improvements in the general physical health of patients undergoing total hip arthroplasty (THA). Data were prospectively collected on 63 THA patients (28 males and 35 females). The primary outcome measure was the improvement in general health (Short Form-12 Health Survey questionnaire) at three months post-THA. Patients with body mass index > 28 kg/m² showed greater improvements in function and in the physical component of general health after THA. Stepwise regression analyses revealed that the BMI and WOMAC general index were independent and significant predictors of physical function and together explained 34.2% of the variance in physical function scores. These findings suggest that the body mass index before surgery and improvements in hip function are relevant contributors to post-THA improvements in general health.     

Patellar Height After Total Knee Arthroplasty: Comparison of 3 Methods

Background

Total knee arthroplasty (TKA) is the gold standard procedure for knee osteoarthritis. However, there have been conflicting reports concerning whether TKA is associated with modifications in patellar height. This controversy might be partially explained by the diversity of methods used to measure patellar height. Therefore, we aimed at assessing the reproducibility of 3 radiological indices commonly used to evaluate patellar height—Insall-Salvati (IS), Blackburne-Peel (BP), and Caton-Deschamps (CD) ratios. Additionally, we aimed at evaluating the short-term differences between preoperative and postoperative patellar heights as measured by those 3 methods.

The Safety and Efficacy of the Anterior Approach Total Hip Arthroplasty as per Body Mass Index

BackgroundObesity is associated with component malpositioning and increased revision risk after total hip arthroplasty (THA). With anterior approaches (AAs) becoming increasingly popular, the goal of this study was to assess whether clinical outcome post-AA-THA is affected by body mass index (BMI).MethodsThis multicenter, multisurgeon, consecutive case series used a prospective database of 1,784 AA-THAs (1,597 patients) through bikini (n = 1,172) or standard (n = 612) incisions. Mean age was 63 years (range, 20-94 years) and there were 57.5% women, who had a mean follow-up of 2.7 years (range, 2.0-4.1 years). Patients were classified into the following BMI groups: normal (BMI < 25.0; n = 572); overweight (BMI: 25.0-29.9; n = 739); obese (BMI: 30.0-34.9; n = 330); and severely obese (BMI ≥ 35.0; n = 143). Outcomes evaluated included hip reconstruction (inclination/anteversion and leg-length, complications, and revision rates) and patient-reported outcomes including Oxford Hip Scores (OHS).ResultsMean postoperative leg-length difference was 2.0 mm (range: ?17.5 to 39.0) with a mean cup inclination of 34.8° (range, 14.0-58.0°) and anteversion of 20.3° (range, 8.0-38.6°). Radiographic measurements were similar between BMI groups (P = .1-.7). Complication and revision rates were 2.5% and 1.7%, respectively. The most common complications were fracture (0.7%), periprosthetic joint infection (PJI) (0.5%), and dislocation (0.5%). There was no difference in dislocation (P = .885) or fracture rates (P = .588) between BMI groups. There was a higher rate of wound complications (1.8%; P = .053) and PJIs (2.1%; P = .029) among obese and severely obese patients. Wound complications were less common among obese patients with the ‘bikini’ incision (odds ratio 2.7). Preoperative OHS was worse among the severely obese (P < .001), which showed similar improvements (Change in OHS; P = .144).ConclusionAA-THA is a credible option for obese patients, with low dislocation or fracture risk and excellent ability to reconstruct the hip, leading to comparable functional improvements among BMI groups. Obese patients have a higher risk of PJIs. Bikini incision for AA-THA can help minimize the risk of wound complications.     

Total knee arthroplasty: Limb length discrepancy and functional outcome

Background:

Limb length discrepancy and its effects on patient function have been discussed in depth in the literature with respect to hip arthroplasty but there are few studies that have examined the effect on function of limb length discrepency following total knee arthroplasty (TKA). The aim of this study was to determine whether limb length discrepancy after TKA in patients with bilateral osteoarthritis of knee with varus deformity affects functional outcome.

Materials and Methods:

Fifty-four patients with bilateral osteoarthritis of knee with varus deformity, who were operated for total knee arthroplasty from 1996 to 2008, were reviewed retrospectively. The patients were divided into two groups. Thirty patients (mean age 64 years) were operated for unilateral TKA and thirty patients (mean age 65.8 years) were operated for bilateral total knee arthroplasty. Six patients underwent staged surgery and were included in both groups as the time interval between the two surgeries was more than the minimum 6-month follow-up period specified for inclusion in the study. The limb length discrepancy was measured and statistically correlated with the functional component of the Knee Society Score.

Result:

In the unilateral group (n=30), the mean limb length discrepancy was 1.53 cm (range: 0-3 cm) and the mean functional score was 73 (range: 45-100). In the bilateral group (n=30), the mean limb length discrepancy was 0.5 cm (range: 0-2 cm) and the mean functional score was 80.67 (range: 0-100). A statistically significant negative correlation was found between limb length discrepancy and functional score in the unilateral group (Spearman correlation coefficient, r =−0.52, P=0.006), while no statistically significant correlation was found in the bilateral group (Spearman correlation coefficient, r = −0.141, P=0.458).

Conclusion:

Limb length discrepancy affects functional outcome after total knee arthroplasty, especially so in patients of bilateral osteoarthritis with varus deformity undergoing surgery of only one knee.