No influence of body mass index on early outcome following total hip arthroplasty

Impact of wound complications in obese versus non-obese patients undergoing total hip arthroplasty: A meta-analysis

This meta-analysis examined the post-operative wound effect of both obese and non-obese in total hip arthroplasty (THA) patients. To gather as complete an overview as possible, the researchers took advantage of 4 databases-PubMed, Embase, Cochrane Library and Web of Science-to conduct a critical assessment. Following the development of inclusion and exclusion criteria, the researchers evaluated the quality of each document. A total of 9 related trials were conducted to determine the 95% CI (CI) and OR using a fixed-effect model. The final meta-analyses were conducted with RevMan 5.3. Our findings indicate that there is no statistically significant benefit in terms of post-operative wound complications among obese and non-obese patients. Obese subjects had a significantly higher risk of injury than those without obesity (OR, 1.43; 95% CI, 1.04, 1.95, p = 0.03); obesity was also associated with a significantly higher risk of operative site infection than in non-obese subjects (OR, 1.96; 95% CI, 1.76, 2.18, p < 0.0001); and after surgery, there was also a significant increase in the risk of post-operative wound infections among obese subjects than in non-obese subjects (OR, 1.57; 95% CI, 1.34, 1.84, p < 0.0001). However, due to the small size of the cohort study in this meta-study, caution is required in the analysis. More randomized, controlled studies will be needed to validate these results.

Management of Acetabular Bone Loss in Hip Revision Arthroplasty: Case Series Presentation

Considering the increase in life expectancy in the general population and the need for a more active lifestyle, total hip arthroplasty has become an absolutely necessary surgical intervention to maintain these desired results. Along with the evolution of medicine and the increase in the quality and performance of the materials used to make prostheses, the number of patients who benefit from total hip replacement is constantly increasing, and proportionally, the number of patients who will require revision arthroplasty is increasing. Before discussing the need for hip arthroplasty revision, it is necessary to carry out a rigorous clinical and imaging examination for differential diagnosis with other pathologies such as low back pain, the presence of bone or soft tissue tumors, arterial occlusions and claudication, or other systemic diseases. One of the biggest challenges for the orthopedic surgeon in planning a hip revision is the compensation of the remaining acetabular bone defect, either as a result of the osteolysis process or following the process of removing the acetabular component, which in some cases can lead to severe bone loss that is difficult to anticipate in the preoperative planning. In this paper, we will present the short-term results of the use of reinforcement cages fixed with screws and cemented retentive acetabular cups in the case of hip revisions with extensive bone loss. The discussions that derive from the presented series of cases are related to the use of reinforcement cages, which are based on the principle of primary stability obtained with the help of screw fixation but whose risk of osteolysis and implant fixation damage is greater than in the case of implants that also associate biological integration at bone level. The use of reinforcement cages together with the retentive acetabular cup in the case of elderly patients with associated comorbidities, a moderate level of physical activity, and severe muscle insufficiency at the hip level as a result of not using the affected pelvic limb is still a viable solution that allows the patient to walk immediately after the surgery, avoiding the risk of dislocation (especially in patients who use the posterolateral approach) and avoiding morbidity induced by prolonged bed rest.

Mid-Term Migration Behavior of an Uncemented Proximally Anchored Straight Stem-A Retrospective EBRA Migration Analysis

BACKGROUND

Aseptic loosening is one of the most-common causes of the failure of cementless stems. Einzel Bild Röntgen Analyse-Femoral Component Analysis (EBRA-FCA) allows the diagnosis of stem migration, which can be considered a factor in predicting implant survival. The current study aimed to present the migration behavior of a tapered proximally anchored straight stem.

METHODS

This retrospective study reviewed all consecutive patients who received a cementless CBC straight stem (Mathys AG, Bettlach, Switzerland) between 2005 and 2019. We analyzed the migration pattern using the EBRA-FCA software and reviewed their medical histories. In addition, periprosthetic radiolucency was rated according to the Gruen zones and femoral configuration according to Dorr.

RESULTS

A total of 333 stems in 332 patients (female 191; male 141) met our inclusion criteria. The mean age at surgery was 63 (range 21-87) years. Migration analysis by EBRA-FCA showed a mean subsidence of 1.6 mm at final follow-up at 96 months with a maximum noted mean subsidence of 2.0 mm at 72 and 84 months. Dorr Type A showed a tendency of less subsidence than did Dorr Type B and was statistically significant at 6 (p = 0.0396) and 72 months (p = 0.0127). The body mass index (BMI) and increased subsidence were not found to correlate (p > 0.05). For this cohort, the overall femoral revision-free rate was 95.2% and the revision-free rate for aseptic loosening was 99.1%.

CONCLUSIONS

The results showed migration behavior in cementless stems with initial increased migration and subsequent secondary stabilization, suggesting an excellent long-term outcome. Stem migration of this tapered proximally anchored stem might be lower in Dorr Type A than in Dorr Type B femurs without being statistically significant at all time points.

Could Short Stems THA Be a Good Bone-Saving Option Even in Obese Patients?

Short femoral stems, with preservation of the femoral bone stock, are commonly used in recent years for hip replacement in younger and more active patients. Obesity is increasingly spreading even in the younger population. The aim of this case-series study is to evaluate short stems compared to traditional hip prostheses in the obese population. A total of 77 consecutive patients with a BMI greater than or equal to 30 Kg/m2 were enrolled in this prospective study and were divided into two groups: 49 patients have been implanted with short stems while 28 patients were implanted with traditional stems. All the patients were treated for primary osteoarthritis or avascular necrosis and all the stems were implanted by the same surgeon using a posterior approach. Clinical (Harris Hip Score—HHS, Western Ontario and McMaster Universities Osteoarthritis Index—WOMAC, visual analogue scale—VAS, 12-item Short Form Health Survey—SF-12) and radiographic outcomes were recorded. Radiological evaluations were carried out by three different blinded surgeons. A statistical analysis was performed (chi-square, t-test, Wilcoxon Rank Sum Test, 2-factor ANOVA). At a mean follow-up of 42.6 months both groups showed a marked improvement in pain and in the clinical scores between pre- and post-surgical procedures (p < 0.05) with no significant differences between the two groups at last follow-up (p > 0.05). The radiological evaluations, with high concordance correlation between the three blinded surgeons (ICC consistently >0.80), showed good positioning and osseointegration in all cases, with no significant differences in the restoration of the joint geometry and complications. No revisions were recorded during the follow-up period. In conclusion, short stems appear to be a good option for bone preservation even in obese patients, showing comparable results to traditional implants.

Is Obesity Associated with Higher Complication Rates in Total Hip Arthroplasty for High-Riding Dysplastic Hips?

OBJECTIVE

Developmental dysplasia of the hip (DDH) is a disabling pathology leading to hip problems, such as painful arthritic hip, unstable hip, etc. Total hip arthroplasty (THA) is an effective treatment modality for this condition. Obesity has been shown to be associated with increased rates of complications following orthopaedic surgeries (Journal of Arthroplasty 20:46-50). The hypothesis of this study was that patients with a body mass index (BMI) greater than 30 (obese), who undergo total hip arthroplasty for dysplastic hip, are associated with longer operative and anaesthetic times, longer hospital stays and higher re-admission rates within 30 days.

METHODS

All the cases of total hip arthroplasty in patients with high-riding dysplastic hips were reviewed. Evaluation was made of a total of 68 patients comprising 64 females and 4 males, classified into two groups. Patients with BMI < 30 kg/m2 formed the non-obese group and patients with BMI ≥ 30 kg/m2 the obese group.

RESULTS

The mean age was 44.67 ± 6.49 years. BMI was < 30 in 44 (64.7%) patients and > 30 in 24 (35.3%) patients. The data analysis showed that mean surgical time, anaesthesia duration and re-admission rate were significantly higher in the group with BMI ≥ 30(obese) as compared to the group with BMI < 30 (non-obese) (p < 0.01). The complication rate was determined to be higher in the obese group (p < 0.05).

CONCLUSION

Obese patients performed with total hip arthroplasty for high-riding dysplastic hips had more complications and higher rates of re-admission to hospital compared with the non-obese patients.

Factors Affecting Periprosthetic Bone Loss after Hip Arthroplasty

Periprosthetic bone loss may lead to major complications in hip arthroplasty, including aseptic loosening, implant migration, and even periprosthetic fracture. Such a complication leads to revision surgeries, which are expensive, technically demanding, and result in a low satisfaction rate. Therefore, a study was conducted of the factors affecting the periprosthetic bone loss around the stem that caused these complications. Factors influencing periprosthetic bone loss include demographic factors such as age, sex, obesity, smoking, and comorbidity including diabetes and osteoporosis. The implant design and fixation method are also factors that are determined before surgery. In addition, there are surgical factors, such as surgical approach and surgical technique, and we wish to investigate the factors affecting periprosthetic bone loss around the stem by comparing the effects of postoperative rehabilitation protocols and osteoporosis drugs.

The Influence of Obesity on Hip Pain, Function, and Satisfaction 10 Years Following Total Hip Arthroplasty

BACKGROUND

The prevalence of obesity is rising, and increasing numbers of joint arthroplasty surgeries are being performed on obese patients. Concern exists that obesity increases surgical risk; however, its impact on function following total hip arthroplasty (THA) is inconsistently affirmed and less understood. A paucity exists in the literature pertaining long-term objective functional measures. Therefore, we investigated the impact of obesity on hip pain, function, and satisfaction 10 years following THA.

METHODS

This single-center, prospective, observational study categorized consecutive THA patients according to their body mass index to nonobese (<30 kg/m²) and obese (≥30 kg/m²) groups. Preoperative assessment included a numerical pain rating and the Oxford Hip Score. These were repeated along with a 6-minute walk test and a Likert satisfaction scale at 3 months, 1, 5, and 10 years postoperatively.

RESULTS

The series included 191 primary THA patients. No significant differences were found in hip pain or function between the obese and nonobese groups. Obese patients however had poorer walking capacity (P = .008), were more likely to use walking aids (P = .04), and were less satisfied (P = .04) at 10 years.

CONCLUSION

THA confers significant long-term symptom resolution irrespective of obesity; however, despite undergoing surgery, obese patients can be counseled they may not be as satisfied as or achieve the same walking capacity as nonobese individuals.

Greater risks of complications, infections, and revisions in the obese versus non-obese total hip arthroplasty population of 2,190,824 patients: a meta-analysis and systematic review

BACKGROUND

Obesity is an epidemic, especially in developed countries. This affects the general health of these patients, especially when they are having a major surgical procedure such as total hip arthroplasty (THA). Several articles have described the effects of obesity on THA with varying conclusions. This meta-analysis aims to compare the outcomes, complications, and peri-operative parameters of THA in the obese (BMI≥30 kg/m²) vs non-obese (BMI<30 kg/m²) population as well as a subgroup analysis of morbidly obese (BMI≥40 kg/m²) vs non-obese population.

METHODS

A multi-database search was performed according to PRISMA guidelines. Data from studies assessing the outcomes and complications of THA in the obese and non-obese population were extracted and analyzed.

RESULTS

Sixty-seven studies were included in this meta-analysis, consisting of 581,012 obese and 1,609,812 non-obese patients. Meta-analysis could not be performed on patient reported outcome measures due to heterogeneous reporting methods. Obese patients had a higher risk of all complications (OR = 1.53, 95%CI: 1.30-1.80, P < 0.001), deep infections (OR = 2.71, 95%CI: 2.08-3.53, P < 0.001), superficial infections (OR = 1.99, 95%CI: 1.55-2.55, P < 0.001), dislocations (OR = 1.72, 95%CI: 1.66-1.79, P < 0.001), reoperations (OR = 1.61, 95%CI: 1.40-1.85, P < 0.001), revisions (OR = 1.44, 95%CI: 1.32-1.57, P < 0.001), and readmissions (OR = 1.37, 95%CI: 1.15-1.63, P < 0.001). When sub-group analysis of morbidly obese (BMI≥40 kg/m²) patients was performed, the risks of all these parameters were even greater.

CONCLUSION

Obese and morbidly obese patients are at higher risks of complications post THA than non-obese patients. Surgeons should be aware of these risks in order to counsel patients and adopt prophylactic strategies to reduce these risks where applicable.

Predictors for Unfavorable Early Outcomes in Elective Total Hip Arthroplasty: Does Extreme Body Mass Index Matter?

Background

Studies of previous cohorts have demonstrated a controversial association between extreme body mass index (BMI) and complication rates following total hip arthroplasty (THA). The purpose of this study was to compare 30-day perioperative complications in underweight (BMI <18.50 kg/m²), normal-weight (BMI 18.50–24.99 kg/m²), overweight (BMI 25.00–29.99 kg/m²), class I obesity (BMI 30.00–34.99 kg/m²), and morbidly obese (BMI ≥35.00 kg/m²) groups.

Methods

We performed a cohort study including patients who underwent unilateral primary THA by a single surgeon between January 2010 and December 2015 at our institution. We assessed 30-day complications, operation time, operative blood loss, and length of hospital stay.

Results

We identified 1565 primary THAs that were performed in patients with varying BMI levels. Compared with the normal-weight patients, the morbidly obese group had a higher 30-day complication rate (8.9% vs. 2.4%), longer operative time (79 minutes vs. 70 minutes), and more blood loss (376 mL vs. 302 mL). Underweight patients did not present any 30-day complications, and there were no differences among underweight and normal-weight patients regarding complication rates, operative time, or blood loss. The mean length of hospital stay was comparable among the different BMI groups. In the multivariate regression model, higher BMI was not associated with a higher risk of 30-day complications. Independent risk factors for 30-day complications were advanced age, prolonged operative time, and cardiovascular comorbidities.

Conclusion

Although increased operative time, blood loss, and perioperative complications were seen in the morbidly obese patients, BMI alone was not an independent risk factor for a higher 30-day complication rate. Therefore, our data suggest clinicians should make elderly patients aware of increased 30-day complications before the procedure, particularly those with cardiovascular comorbidities. Withholding THA solely on the basis of BMI is not justified.

Aseptic Loosening after THA and TKA - Do gender, tobacco use and BMI have an impact on implant survival time?

Purpose

Aseptic loosening (AL) has been reported to be one of the most frequent complications in Total Knee Arthroplasty (TKA) and Total Hip Arthroplasty (THA). The aim of this study was to identify the effects of gender, current tobacco use and BMI on the incidence of AL and implant survival time in THA and TKA.

Methods

Between July 2012 and December 2016 all patients that were diagnosed with an AL of a primary THA or primary TKA and underwent revision surgery at a single institution were retrospectively reviewed for this study. For each patient gender, current tobacco use, BMI, and implant survival time were obtained from the medical records.

Results

202 patients with 85 THA and 117 TKA were included in this study. There was no impact of the gender on implant survival times (p > 0.05) in THA and TKA. In the TKA group current tobacco use was associated with a significant shorter implant survival time (p < 0.05). For THA and TKA with cemented stem fixation a significant increase of AL was seen in overweight compared to normal weight patients (p < 0.05) and in obese compared to normal weight patients (p < 0.05).

Conclusion

The results demonstrate that current tobacco use and elevated BMI are associated with increased rates of AL in TKA. Also, in THA with cemented stem fixation an elevated BMI is associated with an increased incidence of AL.

Influence of body mass index on sagittal hip range of motion and gait speed recovery six months after total hip arthroplasty

PURPOSE

In practice, obesity leads to poor functional outcomes after total hip arthroplasty (THA). However, in clinical research, the influence of body mass index (BMI) on the gait recovery and kinematics for THA is not well documented. The purpose of this study was to assess the influence of BMI on gait parameters pre-operatively and six months after THA for hip osteoarthritis (OA) patients.

METHODS

We included 76 THA for hip OA: non-obese group (G1): 49 (BMI &lt; 30 kg/²) and obese group (G2): 37 (BMI ≥ 30 kg/m²) with a control group of 61 healthy people. Clinical evaluation (HOOS) and a 3D gait analysis (gait speed and flexion range of the hip (ROM)) were performed before and six months after THA: The gains between the two visits were calculated and we looked for correlations between outcomes and BMI.

RESULTS

Preoperative gait speed and hip ROM were significantly lower in obese patients (speed G1: 0.81 ± 0.22 m/s vs. G2: 0.64 ± 0.23 m/s, p = 0.004 and hip ROM G1: 26.1° ± 7.3 vs. G2: 21.4° ± 6.6, p = 0.005), and obese patients were more symptomatic. At six months, gait speed and hip ROM were significantly lower for all patients compared with the control group. No correlation between gait velocity, hip ROM, and BMI was found. Biomechanical and clinical gains were comparable in the two groups.

CONCLUSIONS

All patients, including obese patients, have significant functional improvement after THA, objectively assessed by gait speed. Even if patients did not fully recover to the level of a healthy control person after THA, functional gain is comparable irrespective of BMI.

Body mass index and in-hospital postoperative complications following primary total hip arthroplasty

BACKGROUND

The influence of obesity measured in terms of body mass index (BMI) on the complication rates following total hip arthroplasty (THA) is a matter of debate.

METHODS

This retrospective study conducted at a tertiary referral centre at Brisbane, Australia, examines the association between BMI and in-hospital postoperative complications, length of operating time and duration of hospital stay in 964 patients, who underwent THA from 2006 to 2010.

RESULTS

Amongst patients undergoing primary THA, when compared to the normal weight patients, those with BMI between 25 kg/m² and 29.9 kg/m² (overweight) and those with BMI between 35 kg/m² and 39.9 kg/m² (obese class II) had lower odds of perioperative complications (odds ratio [OR]: 0.62 (95% confidence intervals [CI], 0.43-0.92, p = 0.016) and OR: 0.60 (95% CI, 0.36- 0.99, p = 0.047 respectively). Patients with BMI less than or equal to 40 kg/m² were also associated with significantly lower odds of cardiac complications ( p = 0.02). With unadjusted regression analysis, it was noted that those with BMI ≥40 kg/m² had the highest odds of developing infectious complications (OR 2.68, 95% CI, 1.08-6.65, p < 0.05). As the BMI increased, there was a statistically significant increase in length of operating time ( p < 0.001).

CONCLUSION

There is a significant impact of BMI on the occurrence of perioperative complications following THA. Compared to normal weight category, the overweight and obese class II patients had a lower likelihood of developing overall, especially cardiac complications. Length of operating time increases along with an increase in BMI.

Total hip arthroplasty outcomes in morbidly obese patients: A systematic review

The increasing prevalence of obesity has resulted in a marked increase in the number of total hip arthroplasties (THAs) carried out in patients with a high body mass index (BMI).

THA in morbidly obese patients is often technically challenging owing to the associated co-morbidities and anatomical factors. Furthermore, the long-term clinical and functional outcomes of the procedure in these patients are not clear.

The aim of this systematic review was to compare the long-term failure rate and functional outcomes of THA in morbidly obese versus non-obese patients.

A literature search of PubMed, EMBASE and PubMed Central was conducted to identify studies that compared the outcomes of THA in patients defined as morbidly obese (BMI ≥ 35) to a control group (BMI < 30). The primary and secondary outcome measures were rate of revision and functional outcome, respectively, in the long term.

Eight studies were included in this review. There were 66,238 THAs in morbidly obese patients and 705,619 THAs in patients with a BMI < 30. The overall revision rate was 7.99% in the morbidly obese patients versus 2.75% in the non-obese controls. The functional outcome was at least comparable to non-obese patients.

This review suggests that morbidly obese patients have a slightly increased revision rate following THA. Importantly, these patients have a functional recovery at least comparable to those with a BMI < 30. Morbidly obese patients should be fully informed of these issues prior to undergoing surgery.

Cite this article: EFORT Open Rev 2018;3:507-512. DOI: 10.1302/2058-5241.3.180011

The impact of body mass index on metatarsalgia surgical outcomes

INTRODUCTION

Several studies have suggested that an increased body mass index (BMI) is a negative factor for forefoot plantar pain but its influence in the surgical correction of metatarsalgia is unknown. The purpose of the present study is to evaluate the influence of the BMI on the surgical outcomes of metatarsalgia. It has been hypothesized that the higher the BMI, the worse the functional outcomes after metatarsalgia surgical treatment at one year follow-up.

MATERIAL AND METHODS

A prospective cohort study that included all patients operated on for third rocker metatarsalgia was conducted. Weil's osteotomy was performed on all the patients operated on. The patients' pre-operative height, weight, and BMI were recorded. The patients were subsequently divided into three groups based on their BMI. There was group 1 or the normal group (18.5 > BMI ≤ 25 kg/m2), group 2 or the overweight group (25 > BMI ≤ 30 kg/m2), and group 3 or the obese group (BMI > 30 kg/m2). Pre-operative, post-operative, and differential AOFAS were used to evaluate and compare the groups. The post-operative VAS was also measured to assess pain. The correlation between the BMI and those variables was also analyzed.

RESULTS

After the exclusion criteria were applied, 107 patients were finally assessed. There were 22 patients (20.6%) in group 1, 52 patients (48.6%) in group 2, and 33 patients (30.8%) in group 3. No correlation was observed between the BMI and AOFAS (p > 0.05). Neither were any differences found when the three groups were compared (p > 0.05). Moreover, no correlation between the BMI and the VAS score was observed (p = 0.690).

CONCLUSION

Obesity does not negatively influence functional outcomes after surgery for metatarsalgia in short to medium term. Regardless of their BMI, patients with propulsive metatarsalgia improve in functionality after surgical treatment.

Obesity Increases the Risk of Postoperative Complications and Revision Rates Following Primary Total Hip Arthroplasty: An Analysis of 131,576 Total Hip Arthroplasty Cases

BACKGROUND

The aim of our study is to evaluate the association of body mass index (BMI) and the risk of postoperative complications, mortality, and revision rates following primary total hip arthroplasty given other potentially confounding patient characteristics in a large cohort study.

METHODS

Using nationwide billing data for inpatient hospital treatment of the biggest German healthcare insurance, 131,576 total hip arthroplasties in 124,368 patients between January 2012 and December 2014 were included. Outcomes were 90-day mortality, 1-year revision procedures (with and without removal or exchange of implants), 90-day surgical complications, 90-day femoral fractures, and overall complications. The effect of BMI on outcome was analyzed using multivariable logistic regression. Risk-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were calculated.

RESULTS

BMI had a significant effect on overall complications (30-34 in kg/m²: OR 1.1, CI 1.0-1.2, P = .014; 35-39: OR 1.5, CI 1.3-1.6, P < .001; ≥40: OR 2.1, CI 1.9-2.3, P < .001; <30: reference). The OR for 1-year revision procedures (30-34: OR 1.2, CI 1.1-1.4, P = .001; 35-39: OR 1.6, CI 1.4-1.8, P < .001; ≥40: OR 2.4, CI 2.1-2.7, P < .001; <30: reference) and 90-day surgical complications increased with every BMI category. For mortality and periprosthetic fractures there was a higher risk only for patients with BMI ≥40.

CONCLUSION

BMI increases the risk of revision rates in a liner trend. Therefore, the authors believe that patients with a BMI >40 kg/m² should be sent to obesity medicine physicians in order to decrease the body weight prior elective surgery.

Can obesity and physical activity predict outcomes of elective knee or hip surgery due to osteoarthritis? A meta-analysis of cohort studies

OBJECTIVE

The aim of this study was to systematically review the literature to identify whether obesity or the regular practice of physical activity are predictors of clinical outcomes in patients undergoing elective hip and knee arthroplasty due to osteoarthritis.

DESIGN

Systematic review and meta-analysis.

DATA SOURCE AND ELIGIBILITY CRITERIA

A systematic search was performed on the Medline, CINAHL, EMBASE and Web of Science electronic databases. Longitudinal cohort studies were included in the review. To be included, studies needed to have assessed the association between obesity or physical activity participation measured at baseline and clinical outcomes (ie, pain, disability and adverse events) following hip or knee arthroplasty.

DATA EXTRACTION

Two independent reviewers extracted data on pain, disability, quality of life, obesity, physical activity and any postsurgical complications.

RESULTS

62 full papers were included in this systematic review. From these, 31 were included in the meta-analyses. Our meta-analysis showed that compared to obese participants, non-obese participants report less pain at both short term (standardised mean difference (SMD) -0.43; 95% CI -0.67 to -0.19; P<0.001) and long term post-surgery (SMD -0.36; 95% CI -0.47 to -0.24; P<0.001), as well as less disability at long term post-surgery (SMD -0.32; 95% CI -0.36 to -0.28; P<0.001). They also report fewer postsurgical complications at short term (OR 0.48; 95% CI 0.25 to 0.91; P<0.001) and long term (OR 0.55; 95% CI 0.41 to 0.74; P<0.001) along with less postsurgical infections after hip arthroplasty (OR 0.33; 95% CI 0.18 to 0.59; P<0.001), and knee arthroplasty (OR 0.42; 95% CI 0.23 to 0.78; P=0.006).

CONCLUSIONS

Presurgical obesity is associated with worse clinical outcomes of hip or knee arthroplasty in terms of pain, disability and complications in patients with osteoarthritis. No impact of physical activity participation has been observed.

PROSPERO REGISTRATION NUMBER

CRD42016032711.

Lower limb arthroplasty: can we produce a tool to predict outcome and failure, and is it cost-effective? An epidemiological study

Background

Although hip and knee arthroplasties are considered to be common elective cost-effective operations, up to one-quarter of patients are not satisfied with the operation. A number of risk factors for implant failure are known, but little is known about the predictors of patient-reported outcomes.

Objectives

(1) Describe current and future needs for lower limb arthroplasties in the UK; (2) describe important risk factors for poor surgery outcomes and combine them to produce predictive tools (for hip and knee separately) for poor outcomes; (3) produce a Markov model to enable a detailed health economic analysis of hip/knee arthroplasty, and for implementing the predictive tool; and (4) test the practicality of the prediction tools in a pragmatic prospective cohort of lower limb arthroplasty.

Design

The programme was arranged into four work packages. The first three work packages used the data from large existing data sets such as Clinical Practice Research Datalink, Hospital Episode Statistics and the National Joint Registry. Work package 4 established a pragmatic cohort of lower limb arthroplasty to test the practicality of the predictive tools developed within the programme.

Results

The estimated number of total knee replacements (TKRs) and total hip replacements (THRs) performed in the UK in 2015 was 85,019 and 72,418, respectively. Between 1991 and 2006, the estimated age-standardised rates (per 100,000 person-years) for a THR increased from 60.3 to 144.6 for women and from 35.8 to 88.6 for men. The rates for TKR increased from 42.5 to 138.7 for women and from 28.7 to 99.4 for men. The strongest predictors for poor outcomes were preoperative pain/function scores, deprivation, age, mental health score and radiographic variable pattern of joint space narrowing. We found a weak association between body mass index (BMI) and outcomes; however, increased BMI did increase the risk of revision surgery (a 5-kg/m2rise in BMI increased THR revision risk by 10.4% and TKR revision risk by 7.7%). We also confirmed that osteoarthritis (OA) severity and migration pattern of the hip predicted patient-reported outcome measures. The hip predictive tool that we developed performed well, with a correctedR2of 23.1% and had good calibration, with only slight overestimation of Oxford Hip Score in the lowest decile of outcome. The knee tool developed performed less well, with a correctedR2of 20.2%; however, it had good calibration. The analysis was restricted by the relatively limited number of variables available in the extant data sets, something that could be addressed in future studies. We found that the use of bisphosphonates reduced the risk of revision knee and hip surgery by 46%. Hormone replacement therapy reduced the risk by 38%, if used for at least 6 months postoperatively. We found that an increased risk of postoperative fracture was prevented by bisphosphonate use. This result, being observational in nature, will require confirmation in a randomised controlled trial. The Markov model distinguished between outcome categories following primary and revision procedures. The resulting outcome prediction tool for THR and TKR reduced the number and proportion of unsatisfactory outcomes after the operation, saving NHS resources in the process. The highest savings per quality-adjusted life-year (QALY) forgone were reported from the oldest patient subgroups (men and women aged ≥ 80 years), with a reported incremental cost-effectiveness ratio of around £1200 saved per QALY forgone for THRs. In the prospective cohort of arthroplasty, the performance of the knee model was modest (R2 = 0.14) and that of the hip model poor (R2 = 0.04). However, the addition of the radiographic OA variable improved the performance of the hip model (R2 = 0.125 vs. 0.110) and high-sensitivity C-reactive protein improved the performance of the knee model (R2 = 0.230 vs. 0.216). These data will ideally need replication in an external cohort of a similar design. The data are not necessarily applicable to other health systems or countries.

Conclusion

The number of total hip and knee replacements will increase in the next decade. High BMI, although clinically insignificant, is associated with an increased risk of revision surgery and postoperative complications. Preoperative pain/function, the pattern of joint space narrowing, deprivation index and level of education were found to be the strongest predictors for THR. Bisphosphonates and hormone therapy proved to be beneficial for patients undergoing lower limb replacement. The addition of new predictors collected from the prospective cohort of arthroplasty slightly improved the performance of the predictive tools, suggesting that the potential improvements in both tools can be achieved using the plethora of extra variables from the validation cohort. Although currently it would not be cost-effective to implement the predictive tools in a health-care setting, we feel that the addition of extensive risk factors will improve the performances of the predictive tools as well as the Markov model, and will prove to be beneficial in terms of cost-effectiveness. Future analyses are under way and awaiting more promising provisional results.

Future work

Further research should focus on defining and predicting the most important outcome to the patient.

Funding

The National Institute for Health Research Programme Grants for Applied Research programme.

Comparing In-Hospital Total Joint Arthroplasty Outcomes and Resource Consumption Among Underweight and Morbidly Obese Patients

BACKGROUND

As orthopedic surgeons search for objective measures that predict total joint arthroplasty (TJA) outcomes, body mass index may aid in risk stratification. The purpose of this study was to compare in-hospital TJA outcomes and resource consumption amongst underweight (body mass index ≤19 kg/m(2)) and morbidly obese patients (≥40 kg/m(2)).

METHODS

Discharge data from 2006 to 2012 National Inpatient Sample were used for this study. A total of 1503 total hip arthroplasty (THA) and 956 total knee arthroplasty (TKA) patients were divided into 2 cohorts, underweight (≤19 kg/m(2)) and morbidly obese (≥40 kg/m(2)). Patients were matched by gender and 27 comorbidities by use of Elixhauser Comorbidity Index. Patients were compared for 13 in-hospital postoperative complications, length of stay, total hospital charge, and disposition. Multivariate analyses were generated by SAS software. Significance was assigned at P value <.05.

RESULTS

Underweight patients undergoing primary TJA had higher risk for developing postoperative anemia compared with morbidly obese patients (TKA: odds ratio [OR], 3.1; 95% CI, 2.3-4.1; THA: OR, 1.8; 95% CI, 1.5-2.3). Underweight THA candidates displayed greater risk for deep venous thrombosis (75.36% vs 24.64%; OR, 3.1; 95% CI, 1.1-8.4). Underweight TJA patients were charged more (TKA: USD 51,368.90 vs USD 40,128.80, P = .001, THA: USD 57,451.8 vs USD 42,776.9, P < .001) compared to the morbidly obese patients. Length of stay was significantly longer for underweight THA patients (4.6 days vs 3.5 days, P = .008) compared to morbidly obese counterparts.

CONCLUSION

Our results indicate underweight, compared to morbidly obese, TJA patients are at a greater risk for postoperative anemia and consume more resources.

[Total hip arthroplasty in overweight osteoarthritis patients]

BACKGROUND

An increasing number of patients scheduled for total hip arthroplasty (THA) are obese and exhibit a different risk profile from that of patients of normal weight.

OBJECTIVES

To provide an overview of the impact of obesity on the outcome of primary THA.

MATERIALS AND METHODS

Literature review and discussion of own epidemiological data.

RESULTS

Obese patients can expect as much functional improvement as non-obese patients after THA. However, peri- and postoperative complication (e.g., periprosthetic infection and dislocation) rates are reported to be increased in obese THA patients.

CONCLUSIONS

The knowledge of obesity-associated risks is the prerequiste for successful THA in obese patients.

Morbid Obesity and Congestive Heart Failure Increase Operative Time and Room Time in Total Hip Arthroplasty

BACKGROUND

Obesity is increasingly common in patients having total hip arthroplasty, and previous studies have shown a correlation with increased operative time in total hip arthroplasty. Decreasing operative time and room time is essential to meeting the increased demand for total hip arthroplasty, and factors that influence these metrics should be quantified to allow for targeted reduction in time and adjusted reimbursement models. This is the first study to use a multivariate approach to identify which factors increase operative time and room time in total hip arthroplasty.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was used to identify a cohort of 30,361 patients having total hip arthroplasty between 2006 and 2012. Patient demographics, comorbidities including body mass index, and anesthesia type were used to create generalized linear models identifying independent predictors of increased operative time and room time.

RESULTS

Morbid obesity (body mass index >40) independently increased operative time by 13 minutes and room time 18 by minutes. Congestive heart failure led to the greatest increase in overall room time, resulting in a 20-minute increase. Anesthesia method further influenced room time, with general anesthesia resulting in an increased room time of 18 minutes compared with spinal or regional anesthesia.

CONCLUSION

Obesity is the major driver of increased operative time in total hip arthroplasty. Congestive heart failure, general anesthesia, and morbid obesity each lead to substantial increases in overall room time, with congestive heart failure leading to the greatest increase in overall room time.

Effect of body mass index on functional outcomes following arthroplasty procedures

AIM: To evaluate the body mass index (BMI) change in arthroplasty patients and its impact on the patients’ functional results.

METHODS: Between October 2010 and May 2013, 606 patients who were operated due to gonarthrosis, coxarthrosis, aseptic loosening of the total knee and hip prosthesis were evaluated prospectively. Patients were operated by three surgeons in three medical centers. Patients who were between 30-90 years of age and who were underwent total knee arthroplasty, total hip arthroplasty, revision knee arthroplasty, or revision hip arthroplasty were included in the study. We excluded the patients who cannot tolerate our standard postoperative rehabilitation program. Additionally, patients who had systemic inflammatory diseases, diabetes mellitus, or endochrinopathies were excluded from the study. The remaining 513 patients comprised our study group. Preoperative functional joint scores, height, weight and BMI of all patients were recorded. We used the Knee Society Score (KSS) for knee and Harris Hip Score (HHS) for hip patients. Postoperative functional scores were measured at 1^st, 6^th and 12^th months and recorded separately at outpatient visits.

RESULTS: The mean age of the patients was 64.7 (range: 30-90) years (207 males/306 females) and the mean follow-up duration was 14.3 (range: 12-26) mo. We found that arthroplasty patients had weight gain and had an increase in BMI at the postoperative 1^st, 6^th and 12^th months. The mean BMI of the patients was 27.7 preoperatively, 27.8 at the postoperative 1^st month, 28.1 at the 6^th month and 28.6 at the 12^th month (P < 0.01). At the last visit, the mean postoperative HHS of the hip arthroplasty patients was 82.2 ± 7.12 (preoperatively, 52.3; 1^st month, 78.2; 6^th month, 81.1; 12^th month, 82.2), and the mean KSS of the knee arthroplasty patients was 79.3 ± 4.31 (preoperatively, 35.8; 1^st month, 75.2; 6^th month, 79.1; 12^th month, 79.3). Worse functional results were noted in the patients who had a BMI increase, however, this correlation was statistically significant only at the postoperative 6^th month (P = 0.03).

CONCLUSION: To prevent the negative functional effects of this weight gain during the postoperative period, arthroplasty patients should be advised for weight control and risky patients should consult with a dietician.

What Host Factors Affect Aseptic Loosening After THA and TKA?

BACKGROUND

Aseptic loosening is the most common cause for revisions after lower-extremity total joint arthroplasties, however studies differ regarding the degree to which host factors influence loosening.

QUESTIONS/PURPOSE

We performed a systematic review to determine which host factors play a role in the development of clinical and/or radiographic failure from aseptic loosening after (1) THA and (2) TKA.

METHODS

Two searches on THA and TKA, respectively, using four electronic databases (EMBASE, CINAHL Plus, PubMed, and Scopus) were conducted. We identified a total of 209 reports that encompassed nine potential host factors affecting aseptic loosening. Inclusion criteria for consideration of scientific clinical reports were that 20 or more patients were involved, with more than 1-year followup, with at least three studies pertaining to each factor, and at least six of the Methodological Index for Non-randomized Studies criteria met, and with raw data for odds ratio (OR) calculations. Twenty-one studies (16 THA studies with 45,779 hips and five TKA studies with 288 knees, respectively) were used to calculate weighted OR and CIs (using the random effects theory) and study heterogeneity for four different host factors in THAs (male sex, high activity level, obesity defined as BMI≥30 kg/m2, and current or former tobacco use) and one factor in TKA (BMI≥30 kg/m2), which were placed in a forest plot.

RESULTS

For THA, male sex (OR, 1.39; 95% CI, 1.22-1.58; p=0.001) and high activity level (University of California Los Angeles [UCLA] activity score≥8 points; OR, 4.24; 95% CI, 2.46-7.31; p=0.001) were associated with aseptic loosening. However, obesity (OR, 1.01; 95% CI, 0.73-1.40; p=0.96), and tobacco use (OR, 1.96; 95% CI, 0.43-8.97; p=0.39) were not associated with an increased risk of aseptic loosening after THA with the numbers available. For TKA, we found no host factors associated with loosening. In particular, obesity (BMI≥30 kg/m2) was not associated with aseptic loosening with the numbers available (OR, 2.28; 95% CI, 0.60-8.62; p=0.22).

CONCLUSIONS

Patients undergoing a lower-extremity total joint arthroplasty who engage in impact sports should be counseled regarding their potential increased risk of aseptic loosening; however, given the weak evidence available, we believe that higher-level studies are necessary to clearly define the risk factors, particularly with newer-generation constructs.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Outcomes and complications following total hip arthroplasty in the super-obese patient, BMI > 50

The results of total hip arthroplasty in 42 primary total hip arthroplasties in super-obese patients (BMI ≥ 50) were reviewed. The mean body mass index for the study group was 53.2 kg/m(2) (range 50-64). The mean preoperative Harris hip score improved from 35 to 74.8 postoperatively (P<0.001). Twenty-four of the THAs had at least one complication. At least one major complication occurred in 11 of the THAs and at least one minor complication in 14 THAs When compared to matched 2:1 control group the super-obese patient had a significantly increased risk to experience a complication (HR 5.6 , CI = 2.8-11.0). Caution should be used when proceeding with primary total hip arthroplasty with a BMI greater than 50.

Revision THA in obese patients is associated with high re-operation rates at short-term follow-up

We performed a retrospective review of 309 consecutive revision THAs from 2005 to 2009. We identified a subgroup of patients with BMI >35 and compared the operative time, rate of complications, ICU admissions, re-admissions, and re-operations to patients with BMI <35 undergoing revision THA. At a mean follow-up of 36.3 months, there was no significant difference in operative time, perioperative complications, or re-admission rate between the two groups. However, a significantly higher rate of re-operation was observed in the obese group (46% vs. 28%, P=0.015). Obese patients were more likely to undergo reoperation for infection (P=0.017). Patients with high BMI contemplating primary THA should be aware of the potential subsequent complications associated with revision surgery should it become necessary.

Uncemented total hip arthroplasty using a tapered femoral component in obese patients: an 18-27 year follow-up study

The purpose of this study was to evaluate the efficacy of an uncemented tapered femoral component in obese patients at a mean follow-up of 23 years. We retrospectively reviewed 119 consecutive uncemented total hip arthroplasties in 105 obese patients using a tapered femoral component between 1983 and 1987. The mean body mass index of these patients was 34 (range 30-47). Complete clinical and radiographic follow-up was obtained on the 55 hips in 47 patients who survived a minimum of 18 years (range 18-27 years). Three femoral components (6%) have been revised, none for aseptic loosening. One was loose by radiographic criteria. These results demonstrate that an uncemented tapered stem can provide excellent fixation in obese patients out to 27 years.

Obesity and total joint arthroplasty: a literature based review

The prevalence of obesity in the population is unlikely to decline, and is likely to contribute to the increasing demand for hip or knee arthroplasty. Conflicting data exist on the risk and benefits of total joint arthroplasty in obese patients. The purpose of this manuscript is to define and identify areas of concern for obese patients undergoing total joint arthroplasty. A workgroup of total joint arthroplasty surgeons from the American Association of Hip and Knee Surgeons (AAHKS) was tasked with identifying key questions regarding obesity and total joint arthroplasty. The workgroup evaluated the available literature and sought to create a review regarding obesity and total joint arthroplasty to complement and guide the surgeon-patient discussion in addition to identifying areas of future research.

Delineating the impact of obesity and its relationship on recovery after total joint arthroplasties

OBJECTIVE

The primary aim of this study was to determine the impact of obesity in predicting short and long-term pain relief and functional recovery in total joint arthroplasty (TJA) either as an independent risk factor or a factor mediated by two chronic conditions associated with obesity-cardiac disease and diabetes mellitus.

METHOD

A prospective observational study of 520 patients with primary joint arthroplasties. Pain and functional outcomes were evaluated with the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index within a month of surgery and then 6 months and 3 years post-operatively. Obesity, cardiac disease and diabetes mellitus were examined as potential risk factors for poor recovery. Patients were classified into four groups based on body mass index (BMI): (normal<25.0 kg/m(2); overweight 25.0-29.9 kg/m(2); obese Class 1 30.0-34.9 kg/m(2); severe obese Class 2&3 35.0 ≥ kg/m(2)). Linear mixed models for each joint type (hip and knee arthroplasty) were developed to examine the pattern of recovery and the effect of obesity.

RESULTS

Ninety-nine (19%) patients were severely obese, 127 (24%) had cardiac disease and 58 (11%) had diabetes mellitus. Baseline pain and functional scores were similar regardless of BMI classification. Severe obesity was a significant risk factor for worse pain and functional recovery at 6 months but no longer at 3 years following total hip and knee arthroplasty. Cardiac disease predicted a slower recovery after hip arthroplasty. No significant interactions existed between obesity and cardiac disease or diabetes mellitus.

DISCUSSION

Severe obesity is an independent risk factor for slow recovery over 3 years for both hip and knee arthroplasties.

The influence of body mass index on life quality and clinical improvement after total hip arthroplasty

BACKGROUND

The effect of body mass index (BMI) on the outcome of total hip arthroplasty (THA) remains controversial. The purpose of this study was to examine whether revision rate and postoperative outcomes following THA were influenced by BMI.

MATERIALS AND METHODS

We retrospectively evaluated 714 patients (751 hips) who underwent primary THA in our department between March 1991 and April 2006. They were followed prospectively for 5-20 years with 24 deaths (24 hips) and 33 losses (34 hips). Patients were separated into three groups based on BMI: underweight, normal and obese groups. A survival analysis was performed using revision as the endpoint, and a case-matched study that was matched for age, gender, and laterality was designed; outcomes were assessed with the Harris Hip score, 36-item short-form health survey, complication rate and radiological examination.

RESULTS

The preoperative scores were lower for the obese group, and the postoperative scores were higher for the normal group. Patients in the obese group obtained the greatest overall improvement in clinical scores from admission to the last follow-up. We found a significantly higher complication rate in the obese group and underweight group. It appears that being underweight was associated with an increased dislocation rate, and obese patients were more likely to have osteolysis, deep vein embolism, and pulmonary thrombosis. The log rank test for survival showed no significant differences among the three groups.

CONCLUSIONS

Abnormal BMI does not prevent functional rehabilitation after THA; however, patients with abnormal BMI have to face higher complication rates and poorer clinical outcomes following this operation.

The influence of obesity on early outcomes in primary hip arthroplasty

Obesity is considered an independent risk factor for adverse outcome after arthroplasty surgery. Data on 191 consecutive total hip arthroplasties were prospectively collected. Body mass index (BMI) was calculated for each patient and grouped into nonobese (BMI <30 kg/m(2)), obese (BMI 30-34.9 kg/m(2)), and morbidly obese (BMI ≥35 kg/m(2)). Primary outcomes included functional improvement (Oxford hip score, 6-minute walk test and Short Form-12 Health Survey general health questionnaire) and postoperative complications. Subgroup analysis of surgeons' overall perception of operative technical difficulty was also performed. This study shows that total hip arthroplasties in obese patients were perceived, by the surgeon, to be significantly more difficult. However, this did not translate to an increased risk of complications, operation time, or blood loss, nor suboptimal implant placement. In addition, our results suggest that obese patients gain similar benefit from hip arthroplasty as do nonobese patients, but morbidly obese patients have significantly worse 6-minute walk test scores at 6 weeks.

Subsidence of a cementless femoral component influenced by body weight and body mass index

PURPOSE

This trial was designed to evaluate the impact of physical characteristics such as body mass index, body weight and height on distal stem migration of a cementless femoral component, as the influence of obesity on the outcome of THA is still debated in literature and conflicting results have been found.

METHODS

In this retrospective cohort study, migration patterns for 102 implants were analysed using the Einzel-Bild-Roentgen-Analyse (EBRA-FCA, femoral component analysis). In all cases the Vision 2000 stem was implanted and combined with the Duraloc acetabular component (DePuy, Warsaw, Indiana).

RESULTS

The mean follow-up was 93 months. EBRA-FCA evaluations revealed a mean subsidence of 1.38 mm after two years, 2.06 mm after five and 2.24 mm after seven years. Five stems loosened aseptically. Correlation between increased migration over the whole period and aseptic loosening was highly significant (p < 0.001). Surgical technique had a significant influence on migration and stem stability (p = 0.002) but physical patient characteristics such as body weight over 75 kg and height over 165 cm also significantly influenced stem subsidence towards progressive migration (p = 0.001, p < 0.001). However, a high BMI did not trigger progressive stem migration (p = 0.87). Being of the male gender raised the odds for increased migration (p = 0.03).

CONCLUSION

Physical characteristics such as body weight and height showed significant influence on migration patterns of this cementless femoral component. The operating surgeon should be aware that body weight above 75 kg and height over 165 cm may trigger increased stem migration and the surgeon should aim to fit these prostheses as tightly as possible. However this study demonstrates that a high BMI does not trigger progressive stem migration. Further investigations are needed to confirm our findings.

Obesity in total hip arthroplasty--does it really matter? A meta-analysis

BACKGROUND AND PURPOSE

Discussion persists as to whether obesity negatively influences the outcome of hip arthroplasty. We performed a meta-analysis with the primary research question of whether obesity has a negative effect on short- and long-term outcome of total hip arthroplasty.

METHODS

We searched the literature and included studies comparing the outcome of hip arthroplasty in different weight groups. The methodology of the studies included was scored according to the Cochrane guidelines. We extracted and pooled the data. For continuous data, we calculated a weighted mean difference and for dichotomous variables we calculated a weighted odds ratio (OR). Heterogeneity was calculated using I(2) statistics.

RESULTS

15 studies were eligible for data extraction. In obese patients, dislocation of the hip (OR = 0.54, 95% CI: 0.38-0.75) (10 studies, n = 8,634), aseptic loosening (OR = 0.64, CI: 0.43-0.96) (6 studies, n = 5,137), infection (OR = 0.3, CI: 0.19-0.49) (10 studies, n = 7,500), and venous thromboembolism (OR = 0.56, CI: 0.32-0.98) (7 studies, n = 3,716) occurred more often. Concerning septic loosening and intraoperative fractures, no statistically significant differences were found, possibly due to low power. Subjective outcome measurements did not allow pooling because of high heterogeneity (I(2) = 68%).

INTERPRETATION

Obesity appears to have a negative influence on the outcome of total hip replacement.

Painful hip arthroplasty: definition

Total hip arthroplasty (THA) has been indicated as the surgical intervention with greatest improvement in pain and physical function. However some patients continue to experience hip pain after elective surgery. We investigate prognostic factors that negatively affect treatment effectiveness and the patient outcome. The "hip region" constitutes the groin, buttock, upper lateral thigh, greater trochanteric area, and the iliac crest. Pain originating from various sources and not directly linked to prosthesis may be perceived here and includes the lumbosacral spine, referred pain from abdominal organs and soft tissue sources such as trochanteric bursitis, tendinitis, hip abductor dysfunction, and inguinal hernia. An accurate assessment of the pain cause is extremely difficult to construct and a complete differential diagnosis is fundamental. We assess all the possible causes of hip pain after THA and we divide them depending on the presence or absence of radiographic signs.

Does morbid obesity affect the outcome of total hip replacement?: an analysis of 3290 THRs

We evaluated the outcome of primary total hip replacement (THR) in 3290 patients with the primary diagnosis of osteoarthritis at a minimum follow-up of two years. They were stratified into categories of body mass index (BMI) based on the World Health Organisation classification of obesity. Statistical analysis was carried out to determine if there was a difference in the post-operative Western Ontario and McMaster Universities osteoarthritis index, the Harris hip score and the Short-Form-12 outcome based on the BMI. While the pre- and post-operative scores were lower for the group classified as morbidly obese, the overall change in outcome scores suggested an equal if not greater improvement compared with the non-morbidly obese patients. The overall survivorship and rate of complications were similar in the BMI groups although there was a slightly higher rate of revision for sepsis in the morbidly obese group. Morbid obesity does not affect the post-operative outcome after THR, with the possible exception of a marginally increased rate of infection. Therefore withholding surgery based on the BMI is not justified.

Predicting short-term outcome of primary total hip arthroplasty:a prospective multivariate regression analysis of 12 independent factors

The purpose of this study was to investigate factors affecting the short-term outcome of primary total hip arthroplasty (THA) and develop a multivariate regression equation to predict the short-term outcome of primary THA. Prospectively collected data for 101 primary THAs performed at a single institution were used in this study. Twelve independent variables were analyzed via correlation and multivariate regression analyses. Correlation analyses showed that three variables significantly influenced Western Ontario and McMaster Universities Osteoarthritis (WOMAC) physical function (PF) score at minimum follow-up of 1 year: preoperative WOMAC PF score (P < .0001), sex (GN, P = .0159), and the presence of preoperative comorbidities (CMB, P = .0246). Multivariate regression analysis yielded the following equation: Outcome = PF0.45 - GN9 + CMB8 + 62, which can be used to predict the general short-term outcome of primary THA.

Hip arthroplasty in morbidly obese patients - intra-operative and short term outcomes

Morbidly obese patients experienced significantly longer operation times (66 minutes) and longer wounds (14.2 cm) compared to normal THA patients (58 minutes and 12.1 cm respectively). However, intra-operative anaesthetic time and length of hospital stay were not significantly different between the MO and normal patients. Improvements in patient outcomes following THA were not significantly different between the MO and normal patients at one year follow-up. Improvements in sagittal range of motion and external rotation were significantly less for MO patients. Intraoperative complication rates were 0% for the MO and 3.5% for the normal patients. Postoperative complication rates were 3.5% for the MO and 0% for the normal patients. THA operation times for MO patients were on average only 8 minutes longer and should not represent a barrier to surgery. Hospital length of stay was not longer for MO patients suggesting they do not represent a greater burden on healthcare resources during THA.

The effect of obesity on the mid-term survival and clinical outcome of cementless total hip replacement

The outcome of total hip replacement (THR) is potentially affected by the body mass index (BMI) of the patient. We studied the outcome of 2026 consecutive primary cementless THRs performed for osteoarthritis. The mean follow-up was 6.3 years (0 to 11.71) and no patient was lost to follow-up for survival analysis. The patients were divided into two groups according to their BMI as follows: non-obese (BMI < 30 kg/m(2)) and obese (BMI > or = 30 kg/m(2)). The obese patient undergoing surgery was found to be significantly younger (p < 0.001). The log-rank test for equality of survival showed no difference in the mid-term survival (p = 0.552) with an estimated survival at 11 years of 95.2% (95% CI 92.5 to 98.0) in the non-obese and 96.7% (95% CI 94.9 to 98.5) in the obese groups. The clinical and radiological outcome was determined in a case-matched study performed on 134 obese individuals closely matched with 134 non-obese controls. The non-obese group was found to have a significantly higher post-operative Harris hip score (p < 0.001) and an increased range of movement, but overall satisfaction with surgery was comparable with that of the obese patients. Radiological analysis of the acetabular and femoral components showed no significant differences with regard to radiolucent lines, osteolysis, ingrowth of the femoral component, the acetabular inclination angle or alignment of the femoral component. Our results suggest that the survival of cementless THR is not adversely affected by obesity. Obese patients can therefore be counselled that despite a lower clinical score, they should expect to be satisfied with the result of their THR with a mid-term survival rate equivalent to that of non-obese patients.

Two-year outcomes in primary THA in obese male veterans administration medical center patients

The objective of this study was to examine the influence of obesity on the rate of infection, dislocation, and overall complications in a group of male patients undergoing primary total hip arthroplasty (THA). The study involved a retrospective review of the association of body mass index (BMI) and dislocation, infection, and complications on 255 consecutive male patients who received a THA. BMI of 40 and greater had significantly more dislocations and approached significance for infections. The present study suggests that the risk of infection and dislocation increases only in highly obese males (BMI > 40) in contrast to other studies that have reported a higher risk infection, dislocation, and complications with a BMI of obesity in females (BMI > 30).

Obesity in total hip replacement

A prospective, multi-centre study was carried out on 1421 total hip replacements between January 1999 and July 2007 to examine if obesity has an effect on clinical outcomes.

The patients were categorised into three groups: non-obese (body mass index (BMI) < 30 kg/m2), obese (BMI 30 to 40 kg/m2) and morbidly obese (BMI > 40 kg/m2). The primary outcome measure was the change in Oxford hip score at five years. Secondary outcome measures included dislocation and revision rates, increased haemorrhage, deep infection, deep-vein thrombosis and pulmonary embolism, mean operating time and length of hospital stay. Radiological analysis assessing heterotopic ossification, femoral osteolysis and femoral stem positioning was performed. Data were incomplete for 362 hips (25.5%)

There was no difference in the change in the Oxford hip score, complication rates or radiological changes at five years between the groups. The morbidly obese group was significantly younger and required a significantly longer operating time. Obese and morbidly obese patients have as much to gain from total hip replacement as non-obese patients.

Does obesity influence the outcome after the operative treatment of ankle fractures?

Many orthopaedic surgeons believe that obese patients have a higher rate of peri-operative complications and a worse functional outcome than non-obese patients. There is, however, inconsistency in the literature supporting this notion.

This study was performed to evaluate the effect of body mass index (BMI) on injury characteristics, the incidence of complications, and the functional outcome after the operative management of unstable ankle fractures.

We retrospectively reviewed 279 patients (99 obese (BMI ≥ 30) and 180 non-obese (BMI < 30) patients who underwent surgical fixation of an unstable fracture of the ankle. We found that obese patients had a higher number of medical co-morbidities, and more Orthopaedic Trauma Association type B and C fracture types than non-obese patients. At two years from the time of injury, however, the presence of obesity did not affect the incidence of complications, the time to fracture union or the level of function.

These findings suggest that obese patients should be treated in line with standard procedures, keeping in mind any known associated medical co-morbidities.

Total hip arthroplasties: what are the reasons for revision?

Primary total hip arthroplasties have reported success rates of greater than 95% in many series with a longer than 10-year follow-up. Revision total hip arthroplasty due to such factors as increased high-activity levels, younger patients undergoing the procedure and increasing life expectancy has become more prevalent. An understanding of the mechanisms and timing of total hip arthroplasty failure can direct efforts aimed at reducing revision rates. This study was conducted to evaluate the indications for revision hip arthroplasty and relate these to the time after the index primary hip arthroplasty. A review of all revision hip arthroplasties at two centres over a 6-year time period identified 225 patients who underwent 237 revisions. The overall mean time to revision was 83 months (range: 0-360 months). The cause of failure was aseptic loosening in 123 hips (51.9%), instability in 40 hips (16.9%) and infection in 37 hips (5.5%). When stratified into two groups (less than 5 years, more than 5 years after the index primary hip arthroplasty), 118 of 237 (50%) revisions occurred in less than 5 years, with 33% due to instability and 24% resulting from infection. The majority of the causes of failure within 5 years in these early revisions were instability and deep infection. The success of hip arthroplasty is likely to be compromized if technical aspects of the surgery for appropriate component positioning and critical protocols to minimise complications such as infection are not given the proper attention.

The impact of tobacco use and body mass index on the length of stay in hospital and the risk of post-operative complications among patients undergoing total hip replacement

We carried out a retrospective cohort study of 3309 patients undergoing primary total hip replacement to examine the impact of tobacco use and body mass index on the length of stay in hospital and the risk of short term post-operative complications. Heavy tobacco use was associated with an increased risk of systemic post-operative complications (p = 0.004). Previous and current smokers had a 43% and 56% increased risk of systemic complications, respectively, when compared with non-smokers. In heavy smokers, the risk increased by 121%. A high body mass index was significantly associated with an increased mean length of stay in hospital of between 4.7% and 7%. The risk of systemic complications was increased by 58% in the obese. Smoking and body mass index were not significantly related to the development of local complications. Greater efforts should be taken to reduce the impact of preventable life style factors, such as smoking and high body mass index, on the post-operative course of total hip replacement.

Bone remodelling around HA-coated acetabular cups : a DEXA study with a 3-year follow-up in a randomised trial

This study was designed to investigate bone remodelling around the cup in cementless THA. Previous studies indicate an advantage of better sealing of the bone-prosthesis interface by HA/TCP coating of implants, inhibiting polyethylene-induced osteolysis. One hundred patients gave informed consent to participate in a controlled randomized study between porous coated Trilogy versus Trilogy Calcicoat (HA/TCP coated). The cup was inserted in press-fit fixation. The femoral component was a cementless porous coated titanium alloy stem (Bi-Metric), with a modular 28-mm CrCo head. The Harris Hip Score (HHS) and bone mineral density (BMD) determined by DEXA scanning were used to study the effect. Measurements revealed no difference between the two groups after 3 years either in the clinical outcome or in terms of periprosthetic bone density. Patients with a body mass index above normal regained more bone mineral than patients with normal weight. This finding supports the assumption that load is beneficial to bone remodelling.