Surgical site infection in overweight and obese Total Knee Arthroplasty patients

Risk factors for infection in patients undergoing knee arthroscopy: A Systematic Review and Meta-analysis

PURPOSE

The primary aim was to determine the risk of infection after knee arthroscopy and to evaluate the risk factors for surgical site infection (SSI).

METHODS

The PubMed/Medline, Embase and Cochrane Library databases were systematically searched, as were the reference lists of previous systematic reviews and meta-analysis manual studies. A random-effects model was used to calculate the estimated pooled odds ratio (OR).

RESULTS

A total of 38,321 potential articles met the initial inclusion criteria. After a review of the titles, abstracts and full texts, the remaining 41 articles were included in the final analysis. We identified 9,089,578 patients who underwent knee arthroscopy in 41 articles. High-quality (class I) evidence showed that autografts (cruciate ligament reconstruction) (OR, 2.66% CI, 1.84-3.86) or high procedure complexity (OR, 2.02;95% CI, 1.69-2.43) had a higher risk of infection, while medium-quality (class II or class III) evidence showed that obesity (BMI ≥ 30 kg/m2) (OR, 1.27; 95% CI, 1.08-1.49) or male (OR, 1.52; 95% CI, 1.32-1.75) or diabetes (OR, 1.71; 95% CI, 1.36-2.14) or tobacco use (OR, 1.65; 95% CI, 1.38-1.97) or preoperative steroid use (OR, 3.41; 95% CI, 2.10-5.54) had a higher risk of infection. The meta-analysis showed that there was no association between age or antibiotic prophylaxis and infection incidence.

CONCLUSIONS

The meta-analysis showed that significant risk factors for infection after knee arthroscopy included obesity, male sex, diabetes, tobacco use, high procedure complexity, graft type, and preoperative steroid use.

LEVEL OF EVIDENCE

Level IV, systematic review of Level III and Level IV studies.

-A machine learning model to predict surgical site infection after surgery of lower extremity fractures

PURPOSE

This study aimed to develop machine learning algorithms for identifying predictive factors associated with the risk of postoperative surgical site infection in patients with lower extremity fractures.

METHODS

A machine learning analysis was conducted on a dataset comprising 1,579 patients who underwent surgical fixation for lower extremity fractures to create a predictive model for risk stratification of postoperative surgical site infection. We evaluated different clinical and demographic variables to train four machine learning models (neural networks, boosted generalised linear model, naïve bayes, and penalised discriminant analysis). Performance was measured by the area under the curve score, Youdon's index and Brier score. A multivariate adaptive regression splines (MARS) was used to optimise predictor selection.

RESULTS

The final model consisted of five predictors. (1) Operating room time, (2) ankle region, (3) open injury, (4) body mass index, and (5) age. The best-performing machine learning algorithm demonstrated a promising predictive performance, with an area under the ROC curve, Youdon's index, and Brier score of 77.8%, 62.5%, and 5.1%-5.6%, respectively.

CONCLUSION

The proposed predictive model not only assists surgeons in determining high-risk factors for surgical site infections but also empowers patients to closely monitor these factors and take proactive measures to prevent complications. Furthermore, by considering the identified predictors, this model can serve as a reference for implementing preventive measures and reducing postoperative complications, ultimately enhancing patient outcomes. However, further investigations involving larger datasets and external validations are required to confirm the reliability and applicability of our model.

How reliable is the soft tissue radiological knee index in predicting superficial surgical site infection following total knee arthroplasty?

INTRODUCTION

The purpose of this study was to evaluate the association between the Soft Tissue Radiological Knee (SToRK) Index and the risk of developing a superficial surgical site infection (SSSI) following primary total knee arthroplasty (TKA).

METHODS

The SToRK Index was measured using calibrated long leg radiographs (LLR) in 174 patients undergoing TKA.

RESULTS

A moderate correlation was found between the SToRK Index and body mass index (BMI) (rs=0.574; p < 0.001). The SToRK Index was a better predictor of SSSI in females than males. In females, a SToRK Index cutoff of 2.01 had a sensitivity and specificity of 41.3% and 74.6% for developing SSSI, respectively, with a positive likelihood ratio of 1.63.

CONCLUSION

The SToRK Index can be used as an additional tool in assessing the risk for SSSI after TKA. It might be more predictive in females due to the different fat distribution compared to males.

Effect of weight-adjusted antimicrobial antibiotic prophylaxis on postoperative dosage and surgical site infection incidence in total joint arthroplasty

Surgical site infections (SSI) following total joint arthroplasty pose a significant concern for both providers and patients across the globe. Currently, administration of antimicrobial antibiotic prophylaxis is used throughout the world to reduce the incidence of SSI. However, the correct dosage and frequency of administration remains debatable. In this editorial, we emphasized the determination of the effect of administration of weight-adjusted antimicrobial antibiotic prophylaxis regime on the incidence of SSI and postoperative dosage reduction compared to the conventionally used regime during total joint arthroplasty. The results demonstrated similar efficacy between both regimes with respect to the incidence of SSI. In addition, weight-adjustment led to reduced postoperative dosage and has the potential to reduce chances of achieving lower therapeutic concentration, drug resistance, drug toxicity, and costs.

Prognostic factors for surgical site infection in patients with spinal metastases and following surgical treatment

There were few articles reviewed prognostic factors of surgical site infection (SSI) in patients with spinal metastases following surgery. The purpose of the present study was to systematically: (1) investigate the incidence rates of SSI following spinal metastases surgery; (2) identify the factors which were independently associated with postoperative wound infection. One hundred sixty-seven consecutive adult patients with spinal metastases and underwent surgical treatment were retrospectively enrolled from January 2011 to February 2022. Demographic data, disease and operation-related indicators were extracted and analyzed. Univariate and multivariate logistic analysis model were performed respectively to determine independent risk factors of SSI. 17 cases infection were collected in this study. The overall incidence of SSI after surgery of spinal metastases patients was 10.2%. Univariate regression analysis showed that age (P = .028), preoperative ALB level (P = .024), operation time (P = .041), intraoperative blood loss (P = .030), Karnofsky Performance Status score (P = .000), body mass index (P = .013), American Society of Anesthesiologists > 2 (P = .010), Tobacco consumption (P = .035), and number of spinal levels involved in surgical procedure (P = .007) were associated with wound infection. Finally, the multivariate logistic model demonstrated that body mass index (P = .043; OR = 1.038), preoperative ALB level (P = .018; OR = 1.124), and number of spinal levels (P = .003; OR = 1.753) were associated with SSI occurrence. Surgery on multiple vertebral levels for spinal metastases significantly increases the risk of SSI and weight management, nutritional support and palliative surgery have the positive significance in reducing wound complications. Orthopedist should focus on identifying such high-risk patients and decrease the incidence of wound infection by formulating comprehensive and multi-disciplinary care strategy.

Body Mass Index Is Associated With Myocutaneous Free Flap Reliability: Overcoming the Obesity Obstacle With a Proposed Clinical Algorithm to Identify and Manage High-Risk Patients Undergoing Gracilis Free Flap With Skin Paddle Harvest

INTRODUCTION

The purpose of this study was to evaluate the role of body mass index (BMI) in predicting postoperative complications following myocutaneous free flap transfer. In addition, we sought to identify certain body composition variables that may be used to stratify patients into low- versus high-risk for gracilis myocutaneous free flap with skin paddle failure.

METHODS

Using the National Surgical Quality Improvement Program database, we collected data for all patients who underwent myocutaneous free flap transfer from 2015 to 2021. Demographic data, medical history, surgical characteristics, and postoperative outcomes, including complications, reoperations, and readmissions, were collected. Body mass index was correlated with outcome measures to determine its role in predicting myocutaneous free flap reliability. Subsequently, we retrospectively obtained measurements of perigracilis anatomy in patients who underwent computed tomography angiography bilateral lower extremity scans with intravenous contrast at our institution. We compared body composition data with mathematical equations calculating the potential area along the skin of the thigh within which the gracilis perforator may be found.

RESULTS

Across the United States, 1549 patients underwent myocutaneous free flap transfer over the 7-year study period. Being in obesity class III (BMI ≥40 kg/m2) was associated with a 4-times greater risk of flap complications necessitating a return to the operating room compared with being within the normal BMI range. In our computed tomography angiography analysis, average perigracilis adipose thickness was 18.3 ± 8.0 mm. Adipose thickness had a strong, positive exponential relationship with the area of skin within which the perforator may be found.

CONCLUSIONS

In our study, higher BMI was associated with decreased myocutaneous free flap reliability. Specifically, inner thigh adipose thickness can be used to estimate the area along the skin within which the gracilis perforator may be found. This variable, along with BMI, can be used to identify patients who are considered high-risk for flap failure and who may benefit from additional postoperative monitoring, such as the use of a color flow Doppler probe and more frequent and prolonged skin paddle monitoring.

Rate and factors associated with surgical site infection following aseptic revision fixation of orthopaedic trauma injuries

PURPOSE

The primary aim of this study was to define the rate of infection following revision of fixation for aseptic failure. The secondary aims were to identify factors associated with an infection following revision and patient morbidity following deep infection.

METHODS

A retrospective study was undertaken to identify patients who underwent aseptic revision surgery during a 3-year period (2017-2019). Regression analysis was used to identify independent factors associated with SSI.

RESULTS

Eighty-six patients were identified that met the inclusion criteria, with a mean age of 53 (range 14-95) years and 48 (55.8%) were female. There were 15 (17%) patients with an SSI post revision surgery (n = 15/86). Ten percent (n = 9) of all revisions acquired a 'deep infection', which carried a high morbidity with a total of 23 operations, including initial revision, being undertaken for these patients as salvage procedures and three progressed to an amputation. Alcohol excess (odds ratio (OR) 1.61, 95% CI 1.01-6.36, p = 0.046) and chronic obstructive pulmonary disease (OR 11.1, 95% CI 1.00-133.3, p = 0.050) were independently associated with an increased risk of SSI.

CONCLUSION

Aseptic revision surgery had a high rate of SSI (17%) and deep infection (10%). All deep infections occurred in the lower limb with the majority of these seen in ankle fractures. Alcohol excess and COPD were independent risk factors associated with an SSI and patients with a history of these should be counselled accordingly.

LEVEL OF EVIDENCE

Retrospective Case Series, Level IV.

The effect of body mass index and preoperative weight loss in people with obesity on postoperative outcomes to 6 months following total hip or knee arthroplasty: a retrospective study

BACKGROUND

Few studies have investigated the association between obesity, preoperative weight loss and postoperative outcomes beyond 30- and 90-days post-arthroplasty. This study investigated whether body mass index (BMI) and preoperative weight loss in people with obesity predict postoperative complications and patient-reported outcomes 6 months following total knee or hip arthroplasty.

METHODS

Two independent, prospectively collected datasets of people undergoing primary total knee or hip arthroplasty for osteoarthritis between January 2013 and June 2018 at two public hospitals were merged. First, the sample was grouped into BMI categories, < 35 kg/m2 and ≥ 35 kg/m2. Subgroup analysis was completed separately for hips and knees. Second, a sample of people with BMI ≥ 30 kg/m2 was stratified into participants who did or did not lose ≥ 5% of their baseline weight preoperatively. The presence of postoperative complications, Oxford Hip Score, Oxford Knee Score, EuroQol Visual Analogue Scale and patient-rated improvement 6 months post-surgery were compared using unadjusted and adjusted techniques.

RESULTS

From 3,552 and 9,562 patients identified from the datasets, 1,337 were included in the analysis after merging. After adjustment for covariates, there was no difference in postoperative complication rate to 6 months post-surgery according to BMI category (OR 1.0, 95%CI 0.8-1.4, P = 0.8) or preoperative weight loss (OR 1.1, 95%CI 0.7-1.8, P = 0.7). There was no between-group difference according to BMI or preoperative weight change for any patient-reported outcomes 6 months post-surgery.

CONCLUSION

Preoperative BMI or a 5% reduction in preoperative BMI in people with obesity was not associated with postoperative outcomes to 6 months following total knee or hip arthroplasty.

Differences Between Patients With Diabetes Mellitus and Obese Patients in Occurrence of Peri-Prosthetic Joint Infection: A Systemic Review and Meta-Analysis

Background: To understand the differences between patients with diabetes mellitus and obese patients with respect to the occurrence of peri-prosthetic joint infection (PJI) after lower-extremity joint arthroplasty as well as to identify differences in PJI occurrence at different time periods. Patients and Methods: The Cochrane Library, CINAHL, MEDLINE, and PubMed were searched for literature published between January 2000 and July 2022. Our targets were studies involving patients with PJI who had already been diagnosed as having diabetes mellitus or being obese before receiving lower-extremity joint arthroplasty. Analysis was performed using Comprehensive Meta-Analysis Software (CMA) Version 3 (Biostat, Inc., Englewood, NJ, USA). Results: A total of 53,522 patients with diabetes mellitus and 360,018 obese patients were included. The forest plot for patients with and without diabetes mellitus indicated that patients with diabetes mellitus were more likely to contract PJIs than were patients without diabetes mellitus (odds ratio, 1.84; 95% confidence interval [CI], 1.56-2.16) and that no differences existed among early, delayed, and late PJI occurrence in patients with diabetes mellitus. The forest plot for obese and non-obese patients indicated that obese patients were more likely to contract PJIs than were non-obese patients (odds ratio, 1.86; 95% CI, 1.53-2.14) and that among obese patients, early PJI occurrence was higher than was late PJI occurrence. In addition, the mixed model indicated that obese patients were more likely to develop early PJIs than were patients with diabetes mellitus. Conclusions: Patients with diabetes mellitus and obese patients were more likely to develop PJIs than were patients without diabetes mellitus and non-obese patients, and that obese patients were more likely to develop early PJIs than late PJIs. Also, obese patients were more likely to develop early PJIs than patients with diabetes mellitus.

Increase in Postoperative Body Mass Index in Patients After Total Knee Arthroplasty

Objectives The aim of this is to investigate the changes in body mass index (BMI) following knee arthroplasty and to evaluate their impact on patient-reported outcomes and functional evaluations. Methods This observational study included 90 patients who underwent total knee arthroplasty (TKA) and were followed up for a median period of 2.6 years. BMI measurements were recorded before and after surgery, and patient-reported outcomes and functional evaluations were assessed using standardized scales and tests. Results Following TKA, BMI increased statistically significantly (Wilcoxon signed-rank test, p < 0.000). In addition, half of the patients experienced an increase in BMI, with 32% moving up in their BMI category. However, there were no clinically significant differences in patient-reported outcomes or functional evaluations between the group that gained BMI and the group that maintained or lost BMI. Conclusion This study reveals that patients tend to have increased BMI following TKA. However, these BMI changes do not significantly impact patient-reported outcomes or functional evaluations. It underscores the importance of patient education regarding healthy lifestyle habits, including diet and physical activity, to address postoperative weight gain effectively.

Development of a nomogram to predict surgical site infection after open reduction and internal fixation for closed pilon fracture: a prospective single-center study

BACKGROUND

To explore the risk factors and develop a nomogram in order to predict surgical site infection (SSI) after open reduction and internal fixation (ORIF) for closed pilon fractures (CPF).

METHODS

A prospective cohort study with one-year follow-up was carried out in a provincial trauma center. From January 2019 to January 2021, 417 adult patients with CPFs receiving ORIF were enrolled. A Whitney U test or t test, Pearson chi-square test, and multiple logistic regression analyses were gradually used for screening the adjusted factors of SSI. A nomogram model was built to predict the risk of SSI, and the concordance index (C-index), the receiver operating characteristic (ROC) curve, calibration curve and decision curve analysis (DCA) were used for evaluating the prediction performance and consistency of the nomogram model. The bootstrap method was employed to test the validity of the nomogram.

RESULTS

The incidence of SSI after ORIF for CPFs was 7.2% (30/417): 4.1% (17/417) of superficial SSIs and 3.1% (13/417) of deep SSIs. The most common pathogenic bacteria were Staphylococcus aureus (36.6%, 11/30). The multivariate analysis showed tourniquet use, longer preoperative stay, lower preoperative albumin (ALB), higher preoperative body mass index (BMI) and hypersensitive C-reactive protein (Hs-CRP) were independent risk factors of SSI. Additionally, the C-index and bootstrap value of the nomogram model were 0.838 and 0.820, respectively. Finally, the calibration curve indicated that the actual diagnosed SSI had good consistency with the predicted probability, and the DCA showed that the nomogram had clinical value.

CONCLUSIONS

Tourniquet use, longer preoperative stay, lower preoperative ALB, higher preoperative BMI and Hs-CRP were five independent risk factors of SSI after closed pilon fractures treated by ORIF. These five predictors are shown on the nomogram, with which we may be able to further prevent the CPS patients from SSI. Trial registration NO 2018-026-1, October /24/2018, prospectively registered. The study was registered in October 24, 2018. The study protocol was designed based on the Declaration of Helsinki and admitted by the Institutional Review Board. The ethics committee approved the study on factors related to fracture healing in orthopedic surgery. Data analyzed in the present study were acquired from the patients who underwent open reduction and internal fixation from January 2019 to January 2021.

Similar infection rates in a new wound closure method following knee arthroplasty

Surgical site infections, defined as acute wound infections requiring surgical intervention within 90 days post-surgery, were retrospectively compared between a novel, zipper-like closure method (ZM) and staples in 682 patients (904 knees) and 772 patients (971 knees), respectively. The incidence of deep infections was 0.6% for staples and 0.2% for ZM (p = 0.169) and superficial infections was 0.1% for staples and 0.0% for ZM (p = 0.518). With no difference in wound complications, the ZM may be preferred since the two-week post-operative clinic visit required for wound check and staple removal was eliminated, thereby, decreasing clinic volume.

Greater risk of all-cause revisions and complications for obese patients in 3 106 381 total knee arthroplasties: a meta-analysis and systematic review

BACKGROUND

Obesity is a major public health issue and has considerable implications on outcomes of total knee arthroplasty (TKA). However, there has been conflicting evidence and conclusions on the effects of obesity on TKA. This meta-analysis compares the outcomes, complications, and peri-operative parameters of TKA in the obese (body mass index [BMI] ≥ 30 kg/m² ) versus non-obese (BMI < 30 kg/m² ) population as well as subgroup analysis of morbidly obese (BMI ≥ 40 kg/m² ) versus non-obese population.

METHODS

A meta-analysis was conducted with a multi-database search according to PRISMA guidelines on 12 September 2019. Data from all published literature meeting inclusion criteria were extracted and analysed.

RESULTS

Ninety-one studies were included, consisting of 917 447 obese and 2 188 834 non-obese TKA. Obese patients had higher risk of all-cause revisions (odds ratio [OR] = 1.15, 95% CI: 1.08-1.24, p < 0.0001), all complications (OR = 1.21, 95% CI: 1.06-1.38, p = 0.004), deep infections (OR = 1.47, 95% CI: 1.27-1.69, p < 0.0001), superficial infections (OR = 1.59, 95% CI: 1.32-1.91, p < 0.0001), wound dehiscence (OR = 1.46, 95% CI: 1.24-1.72, p < 0.0001) and readmissions (OR = 1.21, 95% CI: 1.05-1.40, p = 0.009). Subgroup analysis of morbidly obese patients revealed greater risks of all-cause revisions (OR = 1.25, 95% CI: 1.10-1.43, p = 0.0009), deep infections (OR = 1.98, 95% CI: 1.05-3.75, p = 0.04), superficial infections (OR = 2.44, 95% CI: 2.08-2.88, p < 0.0001) and readmissions (OR = 1.33, 95% CI: 1.20-1.47, p < 0.0001). No analysis was performed on patient reported outcome measures due to heterogeneous reporting methods.

CONCLUSION

Obese and morbidly obese patients have higher risks of revisions and infections post TKA. Surgeons should counsel patients of these risks during the informed consenting process and adopt preventative strategies into clinical practice to reduce risks where possible. In conclusion, obesity is a significant, modifiable risk factor for increased complications following TKA.

Low post-arthroplasty infection rate is possible in developing countries: long-term experience of local vancomycin use in Iran

Background

Utilizing intrawound vancomycin powder in TKA surgery has yielded rather contrasting results in the current literature. Furthermore, CDC criteria, although effective in general, are not specifically designed for post-TKA infections. Here, we present a 7-year experience of vancomycin use in primary TKA in a high-volume tertiary knee center in Iran. Also, new criteria are proposed to detect suspected superficial post-TKA infections.

Methods

This is a retrospective analysis of primary total knee arthroplasties performed in a tertiary knee center, from March 2007 to December 2018, by a single senior knee surgeon. All patients with follow-up periods of less than 1 year were excluded from the study. Since March 2011, all patients received vancomycin (powder, 1 g) before water-tight closure of the joint capsule. A comparison was made between this group and historical control subjects (operated from March 2007 to March 2011).

Results

Altogether, 2024 patients were included in the study. The vancomycin and the control groups included 1710 and 314 cases respectively. Patients were mostly women (male to female ratio, 1 to 4), with a mean age of 65.20 (SD = 10.83) years. In the vancomycin group, the rate of suspected SII (1.87%) and PJI (0.41%) was significantly lower than the control group (P = 0.002).

Conclusions

Our experience shows that application of local vancomycin during TKA surgery could be a reasonable infection prevention measure, although prospective randomized studies are required to evaluate its efficacy.

Effects of body mass index on outcomes of total knee arthroplasty

PURPOSE

The aim of this study was to group the patients with total knee arthroplasty(TKA) surgery according to the World Health Organization (WHO) obesity classification and to evaluate the effects of body mass index (BMI) on complication rates, the functional and clinical outcomes of the patients after TKA.

METHODS

Between 2011 and 2018, 588 patients who underwent TKA by a single surgeon were retrospectively evaluated. According to WHO's classification criteria, 588 patients were divided into 5 groups such as normal (< 25.0 kg/m², n: 138, 23.4%), overweight (25.0-29.9 kg/m² n: 201, 34.1%), class I obese (30.0-34.9 kg/m² n: 124, 21%), class II obese (35-39.9 kg/m² n: 82, 13.9%) and class III obese (> 40 kg/m² n: 43 7.6%). Groups were compared in terms of age, sex, surgical side, follow-up period, case duration, prosthesis infection and aseptic prosthesis loosening rates, Knee Injury and Osteoarthritis Outcome Score (KOOS), Lysholm functional scores and knee flexion degrees.

RESULTS

There was a statistically significant difference between the groups in terms of prosthesis infection or aseptic prosthesis loosening following TKA. The incidence of these complications increased as BMI increased (X2: 20,079, p: 0.01). Postoperative knee flexion degrees, KOOS and Lysholm scores were significantly different between the groups (p: 0.000). As BMI increased, clinical and functional outcomes deteriorated.

CONCLUSION

Obesity is one of the most important risk factors for prosthesis infection and aseptic prosthesis loosening which can be seen after TKA. High BMI values also adversely affect clinical and functional outcomes after TKA.

Epidemiology of painful knee after total knee arthroplasty in a tertiary care center: Assessment by decision tree

BACKGROUND

Painful knee after arthroplasty concerns up to 21% of patients at six months. We aimed to evaluate: the application of a decision tree to explain painful knee after total knee arthroplasty (TKA), the rate of unexplained pain after complete algorithmic screening. The aim of the study was to evaluate the causes of painful TKA. Our hypothesis was that it is possible to find the cause of the pain in more than 90% of cases.

METHODS

A single-center retrospective study analyzed all 1130 consultations between 1 April 2017 and 31 July 2018. We included all patients consulting for unexplained chronic painful knee arthroplasty.

RESULTS

We included 112 knees in 105 patients as unexplained painful knee arthroplasty. Final diagnostic status was no diagnosis in seven (6.3%) cases; infection in five (4.5%); instability without real dislocation in three (2.7%); placement error in two (1.8%), due to rotational problems; loosening in 25 (22.3%): 24 (21.4%) tibial and two (1.8%) femoral; polyethylene wear in nine (8.0%); periarticular pain in 37 (33.9%): 20 with quadriceps deficiency, four with iliotibial tendinitis, four with pes bursitis, six with stiffness, and three with prepatellar bursitis); zero material problems; projected pain in 21 (18.8%); and complex regional pain syndrome in three (2.7%) cases, improved by gentle physiotherapy.

CONCLUSIONS

The present study was original and presents the problem in the context of everyday practice, from the clinician's point of view, with an easy-to-use decision tree that can be implemented to assess painful knee in consultation.

Inconsistent relationship between body weight/body mass index prior to total knee arthroplasty and the 12-year survival

BACKGROUND

The primary hypothesis was that body weight (BW) and body mass index (BMI) significantly impact the long-term survival rate after implantation of a mobile bearing total knee arthroplasty (TKA).

METHODS

A national, multicentric, retrospective study was performed in France. A total of 1604 TKAs were included. The 10-year follow-up was documented, and the influence of BW and BMI on the survival rate was assessed.

RESULTS

There was a significant influence of the BW on the 12-year survival rate for any reason and for infection; but this influence was not proportional to the BW or BMI. There was no significant influence of the BMI on the 12-year survival rate for any reason, for any mechanical reason or for infection.

CONCLUSION

Our results suggest that a higher BMI should not be considered as a risk factor for revision for mechanical purpose if a mobile bearing TKA with confirming design is implanted.

The Effect of Bariatric Surgery Prior to Lower-Extremity Total Joint Arthroplasty: A Systematic Review

BACKGROUND

Obesity is an independent risk factor for osteoarthritis and has been associated with increased rate of complications following lower-extremity total joint arthroplasty (TJA). Bariatric surgery (BS) is a surgical option for weight loss and for reducing obesity-related comorbidities in morbidly obese patients.

PURPOSE/QUESTIONS

The goal of this systematic review was to answer the following questions: (1) Does BS prior to TJA correlate with lower post-operative complication rates in morbidly obese patients undergoing TJA? (2) Does BS have an impact on revision rates following TJA?

METHODS

Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and checklist, a systematic review of medical databases (PubMed/ MEDLINE, Cochrane Library, Web of Science, and Clinicaltrials.gov) was undertaken for articles published in English from January 1990 to September 2018. Inclusion criteria were studies that included at least ten patients who underwent BS prior to TJA, collected data on complications or other outcomes, and followed patients for at least 90 days after TJA. A descriptive and critical analysis of the results was performed.

RESULTS

From 799 studies, 13 met inclusion criteria. A total of 11,770 patients who had undergone bariatric surgery prior to TJA were analyzed. The quality of the evidence ranged between moderate and high. There was no consensus on the effect of previous BS on early- to short-term outcomes reported after TJA.

CONCLUSION

The literature remains conflicted on the impact of BS prior to TJA on early, short-term, and long-term complications after TJA. Additional well-matched, observational studies may further our understanding of the impact of BS prior to TJA on outcomes. In particular the effect of various types of BS prior to TJA on outcomes has yet to be elucidated. Ideally, prospective studies with higher level of evidence will be more definitive on the effects of BS prior to TJA.Prospero Registration Number: CRD42016043025.

Does the body mass index influence the long-term survival of unicompartmental knee prostheses? A retrospective multi-centre study

PURPOSE

The effect of being obese on the long-term survival of total joint arthroplasty is persistently discussed. Considering only studies with large cohort of patients and meta-analysis, a high body mass index has been correlated with a higher incidence of complication but not univocally with a lower survival rate. In this study, we analyzed, retrospectively, the data of patients that received unicompartmental knee prostheses in order to examine if obesity has an effect on clinical outcomes.

METHODS

A retrospective multi-centre study was carried out on 4964 unicompartmental knee replacements between July 2000 and December 2016, the patients involved were 3976, with 988 bilateral cases. The patients were categorized into three groups: non-obese with a body mass index (BMI) < 30 kg/m², obese with BMI ranged between 30 and 39 kg/m², and morbidly obese (BMI ≥ 40 kg/m²). The outcome was measured using the Cox proportional hazards model with end point UKA revision for any reasons. Results were stratified for sex, age, weight, and bi-laterality.

RESULTS

The morbidly obese group was significantly younger and required a significantly longer operating time. No statistical significant differences were observed considering the BMI groups in terms of type of insert, type of tibial component, prosthetic condyle, and prosthesis fixation (p > 0.05; chi-square test).

CONCLUSIONS

Obese and morbidly obese patients have as much to gain from total knee replacement as non-obese patients.

Acceptable Functional Outcomes and Patient Satisfaction Following Total Knee Arthroplasty in Asians with Severe Knee Stiffness: A Matched Analysis

Background

This study evaluated outcomes following total knee arthroplasty for severely stiff knees in Asians.

Methods

Registry data of patients undergoing primary total knee arthroplasty between 2004 and 2013 were collected and retrospectively reviewed. Sociodemographic and anthropometric data together with the Oxford Knee Score and the Knee Society Score (Knee Society Knee Score and the Knee Society Function Score) were collected both preoperatively and postoperatively for up to 2 years. Case subjects consisted of patients with a preoperative flexion range of ≤ 20°. Control subjects consisted of patients with a preoperative flexion range of > 90°. Patients were matched for age, sex, and all preoperative scores in a 2:1 fashion. Two-year outcomes and 5-year revision rates were then compared between cases and controls.

Results

There were 28 cases and 56 controls. Cases had a significantly lower body mass index than the controls (p = 0.003) and had a longer hospital stay (p < 0.0001). At 2 years, cases had a significantly lower flexion range (p < 0.001) and a lower Knee Society Function Score (p = 0.020) than the controls. Cases had a significantly greater improvement in the flexion range (p < 0.001) postoperatively than controls. The mean change in functional outcomes at 2 years was comparable between the two groups. Seventy-one percent of the cases and 88% of controls were satisfied. There was a significant difference in the 5-year revision rate (10% vs 0%, p = 0.013). More cases were discharged to a rehabilitation facility compared to controls (p = 0.011). There were no differences in inpatient complication rates.

Conclusions

Functional outcomes and patient satisfaction were acceptable following total knee arthroplasty in Asian patients with severe knee stiffness.