Obesity is a common in individuals undergoing arthroplasty, and the potential for weight loss with improved mobility may be expected by some. The aim of this study was 1. determine the proportion that achieved weight loss after hip or knee arthroplasty, and 2. examine the effect of obesity on patient reported outcomes (PROMS) and satisfaction with surgery. Participants underwent primary TKA or THA between July 2015 and December 2020 and consented to participation in a research database with baseline PROMS, including weight, BMI, Oxford Knee, or Hip Score, and EQ5D. Participants repeated PROMS at 12 months after surgery with additional questions regarding satisfaction with surgery. 3449 patients completed PROMS 1 year after arthroplasty with weight and BMI. There were 1810 THA and 1639 TKA procedures. The mean baseline BMI was higher in TKA (29.8, SD 5.2) compared to THA (27.7, SD 5.0), p=0.001. A higher proportion of TKA were classified as obese class 1 (29% TKA, 19% THA), obese class 2 (11% TKA and 6% THA), and obese class 3 (5% TKA and 2% THA), p=0.001. The mean weight loss after 1 year was 0.4kg and 0.9kg in obese THA subjects and TKA subjects respectively. In the obese >5kg weight loss was achieved in 13% of TKA and 7% of THA (p=0.001). Obese experienced equivalent improvement in Oxford scores, compared to non-obese subjects. Satisfaction with surgery was reported by 95% of THA and 91% of TKA subjects with no significant differences between BMI group grades (p=0.491 THA and p=0.473 TKA). Preoperative obesity was observed in 44% of TKA and 27% of THA subjects. In the obese only 1 in 10 subjects lost 5kg or more over 12 months. Obese patients experienced equivalent improvements in outcome after arthroplasty and rates of satisfaction with surgery to the non-obese

Obesity is associated with worse outcomes following total knee/hip arthroplasty (TKA/TKA). This study aimed to determine the feasibility of a dietitian-led low-inflammatory weight-loss program for people with obesity awaiting arthroplasty. Quasi-experimental pilot study enrolled people with obesity waitlisted for primary TKA/THA into ‘usual care’ (UC) or weight-loss (low-inflammatory diet) program (Diet). Recruitment occurred between July 2019 and February 2020 at Fairfield and Campbelltown Hospitals. Assessments at baseline, pre-surgery, time of surgery and 90-days following surgery included anthropometric measurements, patient-reported outcomes, serum biomarkers and 90-day postoperative complication rate. 97 people consented to the study (UC, n=47, mean age 67, BMI 37, TKA 79%; Diet, n=50, mean age 66, BMI 36, TKA 72%). Baseline characteristics indicated gross joint impairments and poor compliance with a low-inflammatory diet. Study feasibility criteria included recruitment rate (52%), proportion of diet patients that improved compliance to low-inflammatory diet by ≥10% (57%) and had ≥60% attendance of dietitian consultations (72%), proportion of patients who undertook serum biomarkers (55%). By presurgery assessments, the diet group had more patients who cancelled their surgery due to symptom improvement (4 vs 0), reduced waist-circumference measurements, increased compliance with the Low-Inflammatory diet and preservation of physical activity parameters. More usual care participants experienced at least one postoperative complication to 90-days (59% vs 47%) and were discharged to inpatient rehabilitation (21% vs 11%). There was no difference in weight change, physical function, and patient-reported outcome measures from pre-surgery to 90-days post-surgery, and length of hospital stay. Using pre-determined feasibility criteria, conducting a definitive trial is not feasible. However, intervention audit demonstrated high intervention fidelity. Pilot data suggest our program may promote weight loss but the clinical effects for most are modest. Further research utilising a stronger intervention may be required to assess the effectiveness of a pre-arthroplasty weight-loss intervention

Introduction. We demonstrate the preliminary results with a novel technique to solve large bone defects using two lengthening nails, working together and aligned in a custom made device. An illustrative case that successfully produced 17 cm bone in 3.5 months, is presented. Materials and Methods. A 28 year old healthy male presented with a slowly growing mass in the left femur. No general symptoms were reported, no weight loss, no previous illness. Histopathology, CT and MRI scans revealed a malignant diaphyseal bone tumor. A three-stage trifocal bone transport was projected and conducted based on a 3D model test. Results. Trifocal bone transport using two lengthening nails in a custom made device, reduced the 17 cm bone defect in 3.5 months. Follow up was 9 months. Conclusions. The presented technique successfully solved the clinical problem and is a showcase for further developments of internal devices for complex and large bone losses and lengthenings

In a recent study, 54.5% of patients reporting to arthroplasty clinics in the US were obese. We performed a recent literature review to determine how obesity impacts outcomes in total hip and knee arthroplasty and what must be done to improve outcomes in the obese arthroplasty patient. Specifically, obese patients have shown increased rates of infection, dislocation, need for revision, wound dehiscence, increased operative time and prolonged hospital stay. Additionally, obese TKA patients have been shown to have increased rates of aseptic loosening, thromboembolic events, wound complications, and cardiopulmonary events. Worsening severity of obesity seems to correlate with worsening outcomes and super obesity (BMI>50) has been identified as an independent risk factor for complications. Patients with BMI>35 have shown to be 6.7 times more likely to develop infection after TKA. Patients with BMI>40 have a 3.35 times higher rate of revision for deep infection than those with BMI<35. The odds ratio for major complications increases dramatically beyond BMI>45. How can we improve outcomes in the obese patient? Preoperative care for the obese patient involves nutritional counseling, incorporating weight loss methods, physical therapy, metabolic workup and diagnosis and management of frequent comorbid conditions (OSA, DM2, HTN, HLD, malnutrition, renal failure). Identifying and managing comorbidities is especially important given that some comorbidities such as malnutrition have been shown to be as strong or even stronger an independent risk factor for postoperative TJA complications than obesity. In some cases higher complications were seen which some authors attribute to bariatric patients remaining in a catabolic state after weight loss.  . We know that obesity and its associated comorbid conditions do have worse outcomes and increased complications in TJA patients. We also know that complications proportionately increase with increasing severity of obesity. The super-obese population is at the greatest risk of complication following TJA and preoperative screening and management is essential in reducing complications. Although weight loss is important, bariatric data has shown that it does not solve the problem of obesity in itself and the patient's metabolic state is likely a more important issue. Implant selection is important and strong consideration should be given to avoiding direct anterior approach in the THA obese patient. Understanding of obesity specific complications and treatment options is crucial for patient counseling and optimization to ensure successful treatment in obese TJA patients

To describe the longitudinal trends in patients with obesity and Metabolic Syndrome (MetS) undergoing TKA and the associated impact on complications and lengths of hospital stay. We identified patients who underwent primary TKA between 2006 – 2017 within the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database. We recorded patient demographics, length of stay (LOS), and 30-day major and minor complications. We labelled those with an obese Body Mass Index (BMI ≥ 30), hypertension, and diabetes as having MetS. We evaluated mean BMI, LOS, and 30-day complication rates in all patients, obese patients, and those with MetS from 2006-2017. We used multivariable regression to evaluate the trends in BMI, complications, and LOS over time in all patients and those with MetS, and the effect of BMI and MetS on complication rates and LOS, stratified by year. 270,846 patients underwent primary TKA at hospitals participating in the NSQIP database. 63.71% of patients were obese (n = 172,333), 15.21% were morbidly obese (n = 41,130), and 12.37% met criteria for MetS (n = 33,470). Mean BMI in TKA patients increased at a rate of 0.03 per year (0.02-0.05; p < 0 .0001). Despite this, the rate of adverse events in obese patients decreased: major complications by an odds ratio (OR) of 0.94 (0.93-0.96; p < 0 .0001) and minor complications by 0.94 (0.93-0.95; p < 0 .001). LOS also decreased over time at an average rate of −0.058 days per year (-0.059 to −0.057; p < 0 .0001). The proportion of patients with MetS did not increase, however similar improvements in major complications (OR 0.94 [0.91-0.97] p < 0 .0001), minor complications (OR 0.97 [0.94-1.00]; p < 0 .0330), and LOS (mean −0.055 [-0.056 to −0.054] p < 0 .0001) were found. In morbidly obese patients (BMI ≥ 40), there was a decreased proportion per year (OR 0.989 [0.98-0.994] p < 0 .0001). Factors specifically associated with major complications in obese patients included COPD (OR 1.75 [1.55-2.00] p < 0.0001) and diabetes (OR 1.10 [1.02-1.1] p = 0.017). Hypertension (OR 1.12 [1.03-1.21] p = 0.0079) was associated with minor complications. Similarly, in patients with MetS, major complications were associated with COPD (OR 1.72 [1.35-2.18] p < 0.0001). Neuraxial anesthesia was associated with a lower risk for major complications in the obese cohort (OR 0.87 [0.81-0.92] p < 0.0001). BMI ≥ 40 was associated with a greater risk for minor complications (OR 1.37 [1.26-1.50] p < 0.0001), major complications (1.11 [1.02-1.21] p = 0.015), and increased LOS (+0.08 days [0.07-0.09] p < 0.0001). Mean BMI in patients undergoing primary TKA increased from 2006 - 2017. MetS comorbidities such as diabetes and hypertension elevated the risk for complications in obese patients. COPD contributed to higher rates of major complications. The obesity-specific risk reduction with spinal anesthesia suggests an improved post-anesthetic clinical course in obese patients with pre-existing pulmonary pathology. Encouragingly, the overall rates of complications and LOS in patients with obesity and MetS exhibited a longitudinal decline. This finding may be related to the decreased proportion of patients with BMI ≥ 40 treated over the same period, possibly the result of quality improvement initiatives aimed at delaying high-risk surgery in morbidly obese patients until healthy weight loss is achieved. These findings may also reflect increased awareness and improved management of these patients and their elevated risk profiles

The prevalence of Class III Obesity (BMI ≥ 40 kg/m25) in black women is 18%, three times the 6 national average. Class III obesity is associated with mobility limitations, particularly hip joint 7 deterioration. Therefore black women are highly likely to come to the attention of orthopedic 8 surgeons. Weight loss associated with bariatric surgery should lead to enhanced success of hip 9 replacements. However, we present a case of a black woman who underwent Roux-en-y gastric 10 bypass with the expectation that weight loss would improve her ambulation and if necessary 11 make her a better surgical candidate for hip replacement. Her gastric bypass was successful as her BMI declined from 52.0 kg/m2 to 33.7 kg/m212. However, her hip circumference post weight 13 loss remained persistently high. As a consequence, the soft tissue tunnel geometry presented 14 major challenges. The tunnel depth as well as the immobility of the soft tissue envelope 15 interfered with retractor placement, tissue reflection and adequate surgical access to the 16 acetabulum. Therefore a traditional cup placement could not be achieved. Instead, a 17 hemiarthroplasty was performed. Her pre-surgery Harris Hip Score was 17.0. In the first few 18 months post surgery there were improvements, specifically a decrease in pain and a decreased 19 reliance on external support. But her overall functional independence never improved. This case 20 is presented to raise awareness that improved BMI category post bariatric surgery is not 21 sufficient to guarantee that orthopedic risks have been minimized. Overall, weight loss does 22 improve both the metabolic profile and anesthesia risk, but the success rate of total hip 23 arthroplasties will be low if fat mass (i.e. high hip circumference) in the operative field remains 24 high. We are now repeatedly recognizing this problem but are not finding any case reports on 25 this issue. Therefore we provide a practical approach to evaluate these patients and describe 26 ways we have found to successfully address intra-operative challenges

Obesity is a leading public health concern and it is increasing in prevalence over the last 20 years. Obesity prevalence has doubled in adults and tripled in adolescents. The United States is the leading country in terms of percent obesity. Most alarming is the fact that the fastest growing rates of obesity are in the highest BMI groups. The issue of obesity is a particular concern to arthroplasty surgeons since there is an association between the increasing incidence of obesity and the increasing rate of joint replacement. Also of concern is that obese patients tend to be younger and complication rates and revision rates are higher in young patients which is only compounded by the presence of obesity. The risk of virtually every major complication is substantially higher in obese patients. Of concern, however, is a recent study indicating that bariatric surgery with successful weight loss does not necessarily decrease the complication rate. Obesity is also associated with substantially higher costs. There is some evidence that obesity doesn't necessarily affect implant survival. There is also evidence that the clinical outcomes may not be substantially compromised by the presence of obesity. Based on data from studies such as this, some centers have stated that it is difficult to justify withholding surgery based on BMI alone. The data on weight loss following surgery indicates the vast majority of patients did not lose weight following joint replacement. In one study a higher proportion of patients gained weight than lost weight

Traditionally, arthritis is a disease which generally affects the elderly population. However, the incidence in young patients is well described and is increasing with the ever-growing obese population. Currently, the non-surgical treatment of osteoarthritis consists of corticosteroid injections, hyaluronic acid injections, weight loss, physical therapy, bracing, orthotics, narcotics, and non-steroidal anti-inflammatory drugs (NSAIDS). Oral medications (NSAIDS, tramadol, and opioids) can provide effective pain relief. Improvement with NSAIDs has been reported to be 20% relative to baseline, with better improvements seen with selective cox-2 inhibitors, which also have reduced gastrointestinal and renal toxicity. Additionally, the recent AAOS guidelines strongly recommend using NSAIDs or tramadol for pain relief. Although narcotics are effective analgesics, their use in young arthritic patients can potentially predispose individuals to future opioid dependency, and thus should be used sparingly. The primary purpose of physical therapy is to improve range of motion, strengthen muscles, and improve proprioception. Currently, the AAOS strongly recommends that patients undergo self-management programs, strengthening, low-impact aerobic exercises, and neuromuscular education. Similarly, they moderately recommended that patients with a BMI ≥ 25 undergo weight loss for symptomatic arthritis. Bracing options consist of the following: off-loader braces and transcutaneous nerve stimulation braces. These work to either off-load pressure in the knee or to scramble small nerve pain sensation, respectively. Corticosteroid injections are used to minimise pain and reduce inflammation in the joint associated with arthritis. However, their long-term repetitive use in young patients is not recommended, and current AAOS guidelines are inconclusive on their effectiveness. Additionally, the AAOS guidelines strongly recommend against the use of acupuncture, glucosamine/chondroitin, and hyaluronic acid injections

Aims. Tuberculosis (TB) infection of bones and joints accounts for 6.7% of TB cases in England, and is associated with significant morbidity and disability. Public Health England reports that patients with TB experience delays in diagnosis and treatment. Our aims were to determine the demographics, presentation and investigation of patients with a TB infection of bones and joints, to help doctors assessing potential cases and to identify avoidable delays. Patients and Methods. This was a retrospective observational study of all adults with positive TB cultures on specimens taken at a tertiary orthopaedic centre between June 2012 and May 2014. A laboratory information system search identified the patients. The demographics, clinical presentation, radiology, histopathology and key clinical dates were obtained from medical records. Results. A total of 31 adult patients were identified. Their median age was 37 years (interquartile range (IQR): 29 to 53); 21 (68%) were male; 89% were migrants. The main sites affected were joints (10, 32%), the spine (8, 26%) and long bones (6, 19%); 8 (26%) had multifocal disease. The most common presenting symptoms were pain (29/31, 94%) and swelling (26/28, 93%). ‘Typical’ symptoms of TB, such as fever, sweats and weight loss, were uncommon. Patients waited a median of seven months (IQR 3 to 13.5) between the onset of symptoms and referral to the tertiary centre and 2.3 months (IQR 1.6 to 3.4.)) between referral and starting treatment. Radiology suggested TB in 26 (84%), but in seven patients (23%) the initial biopsy specimens were not sent for mycobacterial culture, necessitating a second biopsy. Rapid Polymerase Chain Reaction-based testing for TB using Xpert MTB/RIF was performed in five patients; 4 (80%) tested positive for TB. These patients had a reduced time between the diagnostic biopsy and starting treatment than those whose samples were not tested (median eight days versus 36 days, p = 0.016). Conclusion. Patients with bone and joint TB experience delays in diagnosis and treatment, some of which are avoidable. Maintaining a high index of clinical suspicion and sending specimens for mycobacterial culture are crucial to avoid missing cases. Rapid diagnostic tests reduce delays and should be performed on patients with radiological features of TB. Cite this article: Bone Joint J 2018;100-B:119–24

Purpose. Weight loss is often advised to our patients and considered to make a substantial difference in most musculoskeletal symptoms. Patients with end stage ankle arthrosis have severe pain, diminished health related quality of life, and limited physical function. They frequently refer to increased weight as a simple indicator of decline in their quality loose weight. Patients assume that weight loss will follow after surgery secondary to increased activity with reduced pain and disability. Method. Changes in the body mass index, mental and physical component of SF36 and Ankle Scale Osteoarthritis of 145 overweight and obese patients after ankle surgery were assessed up to five year after surgery with a mean of 37.1 month follow up from 2002 to 2009. Results. The Ankle Osteoarthritis Scale and Physical component of SF36 significantly improved, by a mean of 34.8, 9.8, respectively after ankle surgery but there was not significant change in Body mass index. Conclusion. Pain and disability of end stage ankle arthritis usually resolve gradually within one and two year after surgery but body mass index changes was insignificant in five year period. In fact following successful ankle fusion or replacement, 1/3 of our patients gained 1 unit BMI or more, 1/3 lost one unit BMI or more and 1/3 remained within one unit of their pre op BMI. This suggests that obesity is a multifactorial and an independent disease

Arthrosis of the hip joint can be a significant source of pain and dysfunction. While hip replacement surgery has emerged as the gold standard for the treatment of end stage coxarthrosis, there are several non-arthroplasty management options that can help patients with mild and moderate hip arthritis. Therefore, the purpose of this paper is to review early prophylactic interventions that may help defer or avoid hip arthroplasty. Nonoperative management for the symptomatic hip involves minimizing joint inflammation and maximizing joint mobility through intra-articular joint injections and exercise therapy. While weight loss, activity modifications, and low impact exercises is generally recommended for patients with arthritis, the effects of these modalities on joint strength and mobility are highly variable. Intra-articular steroid injections tended to offer reliable short-term pain relief (3–4 weeks) but provided unreliable long-term efficacy. Additionally, injections of hyaluronic acid do not appear to provide improved pain relief compared to other modalities. Finally, platelet rich plasma injections do not perform better than HA injections for patients with moderate hip joint arthrosis. Primary hip joint arthrosis is rare, and therefore treatment such as peri-acetabular osteotomies, surgical dislocations, and hip arthroscopy and related procedures are aimed to minimise symptoms but potentially aim to alter the natural history of hip diseases. The state of the articular cartilage at the time of surgery is critical to the success or failure of any joint preservation procedures. Lech et al. reported in a series of dysplastic patients undergoing periacetabular osteotomies that one third of hips survived 30 years without progression of arthritis or conversion to THA. Similarly, surgical dislocation of the hip, while effective for treatment of femoroacetabular impingement, carries a high re-operation rate at 7 years follow up. Finally, as the prevalence of hip arthroscopic procedures continues to rise, it is important to recognise that failure to address the underlying structural pathologies can lead to failure and rapid joint destruction. In summary, several treatment modalities are available for the management of hip pain and dysfunction in patients with a preserved joint space. While joint preservation procedures can help improve pain and function, they rarely alter the natural history of hip disease. The status of the articular cartilage at the time of surgery is the most important predictor of treatment success or failure

There are a number of different non-operative management options for patients with a painful knee secondary to osteoarthritis (OA). In 2013 the American Academy of Orthopaedic Surgeons developed an evidence-based clinical practice guideline addressing treatment of osteoarthritis of the knee. Strength of recommendations were designated as strong, moderate and inconclusive. Strong recommendations included: self-management program, NSAIDs or tramadol and no acupuncture, no glucosamine and chondroitin sulfate and no hyaluronic acid. The “No” recommendations for hyaluronic acid and glucosamine and chondroitin sulfate were quite controversial because orthopaedic surgeons argued that some of their patients benefited from these treatments. Moderate strength recommendations included weight loss, lateral wedge insoles and needle lavage. The evidence-based data was inconclusive with respect to valgus force unloading brace, manual physical therapy, acetaminophen, opioids and pain patches. The effectiveness of corticosteroid and platelet rich plasma (PRP) injections were also inconclusive. Unloader braces are available to decrease pressure on the involved compartment. There is data showing that these braces can be effective for some patients. However, there are concerns with patient compliance because of poor fit and discomfort. These braces seemed to be tolerated best when used for sports activities in patients with medial compartment arthritis. Oral anti-inflammatory agents are effective in relieving pain and are a good first line agent for patients with OA. There is significant interest in the use of PRP injections for management of patients with knee OA particularly when patients have already received a steroid and/or a hyaluronic acid injection. To date there are no appropriately powered multi-centered randomised trials demonstrating that PRP is effective in decreasing pain and function in knee OA. However, there are some studies that suggest PRP can be helpful for patients with OA. Further studies to determine the indications for PRP injections are necessary. PRP injections are not covered by insurance in the United States. In summary, the management of patients with painful OA of the knee needs to be individualised based on patient symptoms and expectations. Non-operative management can be effective in limiting pain and enhancing function

Introduction. Metal-on-polyethylene (MoP) is the most commonly used bearing couple in total hip replacements (THRs). Retrieval studies (Cooper et al, 2012, JBJS, Lindgren et al, 2011, JBJS) report adverse reactions to metal debris (ARMD) due to debris produced from the taper-trunnion junction of the modular MoP THRs. A recent retrospective observational study (Matharu et al, 2016, BMC Musc Dis) showed that the risk of ARMD revision surgery is increasing in MoP THRs. To the authors' best knowledge, no hip simulator tests have investigated material loss from the taper-trunnion junction of contemporary MoP THRs. Methods. A 6-station anatomical hip joint simulator was used to investigate material loss at the articulating and taper-trunnion surfaces of 32mm diameter metal-on-cross-linked polyethylene (MoXLPE) joints for 5 million cycles (Mc) with a sixth joint serving as a dynamically loaded soak control. Commercially available cobalt-chromium-molybdenum (CoCrMo) femoral heads articulating against XLPE acetabular liners (7.5Mrad) were used with a diluted new-born-calf-serum lubricant. Each CoCrMo femoral head was mounted on a 12/14 titanium alloy trunnion. The test was stopped every 0.5Mc, components were cleaned and gravimetric measurements performed following ISO 14242-2 and the lubricant was changed. Weight loss (mg) obtained from gravimetric measurements was converted into volume loss (mm. 3. ) and wear rates were calculated from the slopes of the linear regression lines in the volumetric loss versus number of cycles plot for heads, liners and trunnions. Additionally, volumetric measurements of the head tapers were obtained using a coordinate measuring machine (CMM) post-test. The surface roughness (Sa) of all heads and liners was measured pre and post-test. At the end of the test, the femoral heads were cut and the roughness of the worn and unworn area was measured. Statistical analysis was performed using a paired-t-test (for roughness measurements) and an independent sample t-test (for wear rates). Results and Discussion. The mean volumetric wear rates for CoCrMo heads, XLPE liners and titanium trunnions were 0.019, 2.74 and 0.013 mm. 3. /Mc respectively. There was a statistically significant decrease (p<0.001) in the Sa of the liners post-test. This is in contrast to the femoral heads roughness in which no change was observed (p = 0.338). This head roughness result matches with a previous MoP in vitro test (Saikko, 2005, IMechE-H). The Sa of the head tapers on the worn area showed a statistically significant increase (p<0.001) compared with unworn, with an associated removal of the original machining marks. The mean volumetric wear rate of the head tapers obtained using the CMM (0.028 ± 0.016 mm. 3. /Mc) was not statistically different (p=0.435) to the mean volumetric wear rate obtained gravimetrically (0.019 ± 0.020 mm. 3. /Mc) for the femoral heads. Therefore, wear of the heads arose mainly from the internal taper. The mean wear rates of the CoCrMo taper and titanium trunnion are in agreement with a MoP explant study (Kocagoz et al, 2016, CORR). Conclusion. This is the first long-term hip simulator study to report wear generated from the taper-trunnion junction of MoP hips

The US obesity epidemic has transcended into the arthroplasty patient population and surgeons must assess whether obesity is a risk factor for poor outcomes in total joint arthroplasty (TJA) and determine how it should be managed in order to insure good clinical outcomes. In the United States, 34.9% of adults are currently obese (BMI > 30). In a recent study, 54.5% of patients reporting to arthroplasty clinics in the US were obese. We performed a recent literature review to determine how obesity impacts outcomes in total hip and knee arthroplasty and what must be done to improve outcomes in the obese arthroplasty patient. We know that obesity and its associated comorbid conditions do have worse outcomes and increased complications in TJA patients. We also know that complications proportionately increase with increasing severity of obesity. The super-obese population is at the greatest risk of complication following TJA and pre-operative screening and management is essential in reducing complications. Although weight loss is important, our bariatric data has shown that it does not solve the problem of obesity in itself and the patient's metabolic state is likely a more important issue. Implant selection is important and strong consideration should be given to avoiding direct anterior approach in the THA obese patient. Understanding of obesity specific complications and treatment options is crucial for patient counseling and optimisation to ensure successful treatment in obese TJA patients

Periprosthetic joint infection (PJI) following total knee arthroplasty (TKA) is a devastating complication. It is associated with high morbidity and mortality. It remains, unfortunately, one of the most common modes of failure in TKA. Much attention has been paid to the treatment of PJI once it occurs. Our attention, however, should focus on how to reduce the risk of PJI from developing in the first place. Infection prevention should focus on reducing modifiable risk factors that place patients at increasing risk for developing PJI. These areas include pre-operative patient optimization and intra-operative measures to reduce risk. Pre-operative Modifiable Risk Factors: There are several patient related factors that have been shown to increase patient's risk of developing PJI. Many of these are modifiable risk factors can and should be optimised prior to surgery. Obesity and in particular Morbid Obesity (BMI >40) has a strong association with increased risk of PJI. Appropriate and healthy weight loss strategies should be instituted prior to elective TKA. Uncontrolled Diabetes (Hgb A1C >8) and poor glycemic control around the time of surgery increases the risk for complications, especially PJI. Malnutrition should be screened for in at-risk patients. Low Albumin levels are a risk factor for PJI and should be corrected. Patients should be required to stop smoking 6 weeks prior to surgery to lower risk. Low Vitamin D levels have been show to increase risk of PJI. Reduction of colonization of patient's nares with methicillin sensitive (MSSA) and resistant (MRSA) staphylococcus should be addressed with a screen and treat program. Intra-operative Measures to Reduce PJI: During surgery, several steps should be taken to reduce risk of infection. Appropriate dosing and timing of antibiotics is critical and a first generation cephalosporin remains the antibiotic of choice. The use of antibiotic cement remains controversial with regards to its PJI prophylactic effectiveness. The utilization of a dilute betadine lavage has demonstrated decreased rate of PJI. Maintaining normothermia is critical to improve the body's ability to fight infection. An alcohol-based skin preparation can reduce skin flora as a cause of PJI. Appropriate selection of skin incisions and soft tissue handling can reduce wound healing problems and reduce development of PJI. Likewise, the use of occlusive dressing has been shown to promote wound healing and reduce PJI rates

As the American population ages and a trend toward performing total hip arthroplasty (THA) in younger patients continues, the number of Americans undergoing THA is projected to increase over time. The advent of the bundled payment system combined with the current medical utilization climate has placed considerable pressure on surgeons to produce excellent results with early functional recovery and short hospital stays. The US obesity epidemic has transcended into the arthroplasty patient population and surgeons must assess whether obesity is a risk factor for poor outcomes in THA and determine how it should be managed. We performed a recent literature review to determine how obesity impacts outcomes in total hip arthroplasty and what must be done to improve outcomes in the obese arthroplasty patient. Our goal is to answer 3 questions: does obesity increase the complication rate in THA, if obesity matters how obese is too obese, and what must be done to improve outcomes in the obese patient?. Ultimately, obesity has been shown to correlate with increased post-operative complications in THA. The arthroplasty surgeon must optimise the obese patient prior to surgery by identifying associated comorbidities and consider malnutrition screening with counseling. Notice should be taken of the degree of obesity as patients with BMI > 40 have demonstrated much higher complication rates. Strong consideration should be given to avoiding direct anterior approach in the obese patient. Healthy weight loss must be encouraged with appropriate patient counseling and treatment in order to achieve success with THA in obese patients.  

Obesity and the diseases linked to it such as diabetes have been associated with higher complication rates and increased medical costs following total hip arthroplasty (THA). Due to the rising prevalence of obesity and the adverse impact it has on the development of osteoarthritis, there has been a worldwide surge in the number of obese patients presenting for THA procedures, including those morbidly obese (BMI > 40) and those who are super-obese (BMI > 50). The Reward. When THA is successful (as is true for the majority of morbidly obese patients) the operation is just as dramatically effective as it is for other patients. Excellent pain relief and dramatically improved function is the result, even though obese patients generally achieve a lower overall level of function than non-obese patients. Morbidly obese patients with a successful THA and without early complications are some of the most grateful of patients. This is especially true if they have been denied surgery for prolonged periods due to their weight and have had to bear severe joint changes and symptoms during a long period of time leading up to arthroplasty. The Risks. There is a nonlinear increase in complications, reoperations, and especially infection with increasing BMI that begins between a BMI of 25 to 30, and rises thereafter with a relative inflection point in some incidence curves for complications at around a BMI of 40. This has caused some surgeons to suggest a BMI of 40 as an upper limit for elective hip arthroplasty. Risks continue to rise after a BMI of 40 and when the BMI is over 50, in our series 52% of patients had at least one complication. Of these 24% had at least one major complication and 33% at least one minor complication with some suffering more than one complication overall. These data make it reasonable to ask whether the outcomes in some morbidly obese patients might be improved by weight loss, bariatric surgical intervention and other measures aimed at optimizing the multiple companion comorbidities and medical conditions (such as diabetes) that often accompany excess weight. Unfortunately there has been limited information to date on the best means for optimizing of these patients, and as important the effectiveness of these interventions, so that the timing and performance of the eventual arthroplasty procedures might have the highest possible success rate. The Costs. The adverse impact of obesity on medical resource utilization and costs associated with THA has been well documented, Due to longer initial length of stay, greater resource utilization, higher early complication rates and any readmissions and reoperations the costs for even a single individual patient can climb dramatically. In a review of data on primary THA patients from our institution, even after adjusting for age, sex, type of surgery, and other comorbidities, for every 5 unit increase in BMI beyond 30 kg/m2 there was an associated $500 higher cost of hospitalization and an increase of $900 in 90-day total costs (p=0.0001). The Future. The numbers of morbidly obese patients with severe osteoarthritis presenting for possible THA will only continue to increase in the years ahead. Comprehensive multidisciplinary programs are urgently needed to better manage obese patients with weight reduction options, optimization of medical comorbidities, and treatment of any associated issues, such as protein malnutrition. When end-stage joint changes and symptoms occur we must have such help to maximise the benefit and reduce the complications of hip arthroplasty in this high risk patient population

Unicompartmental knee replacements (unis) offer an early option for the treatment of osteoarthritis. However there is no standard method for measuring the wear of unis in the laboratory. Most knee simulators are designed for TKA, for which there is an ISO standard. This study is about a wear method for unis, applied to a novel unicompartmental knee replacement (design by PSW). It has a metal-backed UHMWPE femoral component to articulate against a monoblock metallic tibial component. The advantage is reduced resection of strong bone from the proximal tibia for more durable fixation. The femoral component resurfaces the distal end of the femur to a flexion arc of only 42°, the area of cartilage loss in early OA (Fig. 1). We compared this novel bearing couple to the same design but with the usual arrangement of femoral metal and tibial plastic. Our hypothesis was that the wear of the reversed materials would be comparable to conventional and within the range of TKR bearings. The test was conducted on a 4-station Instron-Stanmore force-controlled knee simulator. Both specimen groups (n=4 each) were highly crosslinked UHWMPE stabilized with vitamin E. On each of the four stations, one uni system was mounted on the medial side and one on the lateral, as if a standard TKR was being tested. The ISO-14243-1 walking cycle force-control waveforms were applied for 5 million cycles (Mc) at 1Hz, but with the maximum flexion during the swing phase (usually 58°) curtailed to 35° to maintain the contact within the arc of the femoral component. In-vivo this implant would be inlaid into the distal medial femoral condyle and the articulating surface immediately transitions into native cartilage. In our test set-up there was no secondary surface as such. The reduced flexion occurred during the swing phase where compressive load was low and the effect on the wear would be negligible. Wear was measured gravimetrically at many intervals and corrected by the weight gain of extra two active soak controls per group. After 5 Mc, the average rates of gravimetric weight loss from the UHMWPE femoral and tibial bearings were 4.73±0.266 mg/Mc and 3.07±0.388 mg/Mc, respectively (statistically significantly different, p=0.0007) (Fig. 2). No significant difference was found in wear between medial and lateral placement for specimens of the same type, although the medial side generally wore more. Although the plastic femorals of the reverse design wore more than the plastic tibials, the wear was still low at <5 mg/Mc. The range for typical TKRs using ultra-high molecular weight polyethylene, tested under the same conditions in our laboratory has been 2.85–24.1 mg/Mc. In summary, we adapted the ISO standard TKA wear test for the evaluation of unis, and in this case, a uni with reversed materials. Based on the wear results, this type of ‘early intervention’ design could therefore be a viable option, offering simplicity with less modular parts as well as load sharing with the native articular cartilage

In the USA, 34.9% of adults are currently obese (BMI > 30). Growth in total knee arthroplasty (TKA) is outpacing growth in total hip arthroplasty (THA) largely due to a differential utilization of TKA in overweight patients in the USA. In a recent study, 54.5% of patients reporting to arthroplasty clinics in the USA were obese. From 2006–2010, 61.2% of primary unilateral TKA patients in the USA ACS-NSQIP database were obese. Arthroplasty surgeons are directly affected by the obesity epidemic and need to understand how to safely offer a range of peri-operative care for these patients in order to insure good clinical outcomes. Pre-operative care for the obese patient involves nutritional counseling, weight loss methods, consideration for bariatric surgery, physical therapy, metabolic workup, and diagnosis and management of frequent comorbid conditions (OSA, DM2, HTN, HLD). Obese patients must also be counseled on their increased risk of complications following TKA. In the operating room, several steps can be taken to insure success when performing TKA on obese patients. We recommend performing TKA without the use of a tourniquet in order to prevent fat necrosis and increased pain. The incision is made in 90 degrees of knee flexion, atypically midline proximally and curved distally to the midpoint between the tubercle and the medial edge of the tibia. Care is used to minimise the creation of dead space, and the approach to the knee is an extensile medial parapatellar incision. Closure is in multiple layers. The use of negative pressure dressing following surgery can minimise the early wound drainage that is frequently seen after TKA in obese patients. Post-operative care of the obese patient following TKA involves several unique considerations. Chronic pain and obesity are frequent comorbid conditions and post-operative pain control regimens need to be tailored. Although the physical therapy regimen does not differ in obese patients, obese patients are more likely to be discharged to a rehabilitation facility. Obese patients have a higher rate of all complications compared to healthy weight. All infection and deep infection increased in obese patients in large meta-analysis. Patients with BMI > 35 are 6.7 times more likely to develop infection after TKA. Patients with BMI > 40 have a 3.35 times higher rate of revision for deep infection than those with BMI < 35. The odds ratio for major complications increases dramatically beyond BMI > 45. Although there are a few studies that have demonstrated worse clinical outcome in obese patients following TKA, most studies show no difference in clinical outcomes at short- or long-term follow-up. The arthroplasty surgeon must optimise the obese patient prior to surgery, use intra-operative techniques to maximise success, and anticipate potential problems in the post-operative course in order to achieve success with TKA in obese patients

Periprosthetic joint infection (PJI) is one of the most devastating complications of total joint arthroplasty (TJA). Only a few studies have investigated PJI's impact on the most worrisome of all endpoints, mortality. The purpose of this study was to perform a large-scale study to determine the rates of PJI associated in-hospital mortality, and compare it to other surgical procedures. The Nationwide Inpatient Sample was queried from 2002 to 2010 to assess the risk of mortality for patients undergoing revision for PJI or aseptic failures. Elixhauser comorbidity index and ICD-9 codes were used to obtain patients’ medical conditions and identify PJI. Multiple logistic-regression analyses were used to determine the associated variables with mortality. In-hospital mortality was compared to the followings: coronary-artery bypass graft, mastectomy, prostatectomy, appendectomy, kidney transplant, carotid surgery, cholecystectomy, and coronary interventional procedures. PJI was associated with an increased risk (odds ratio 2.04) of in-hospital mortality (0.77%) compared to aseptic revisions (0.38%). The in-hospital mortality of revision THAs done for PJI (1.38%, 95%CI, 1.12–1.64%) was comparable to or higher than interventional coronary procedure (1.22%, 95%CI, 1.20–1.24%), cholecystectomy (1.13%, 95%CI, 1.11–1.15%), kidney transplantation (0.70%, 95%CI, 0.61%–0.79%) and carotid surgery (0.89%, 95%CI, 0.86%–0.93%) (Figure 1). The following comorbidities were independent risk factors for in-hospital mortality after TJA: liver disease, metastatic disease, fluid and electrolyte disorders, coagulopathy, weight loss and malnutrition, congestive heart failure, pulmonary circulation disorder, renal failure, and peripheral vascular disease. PJI is associated with a two-fold increase in mortality and have mortality rates comparable to kidney transplantation and carotid surgery. Considering the fact that patients with PJI often require multiple surgical procedures, the rate of actual in-hospital mortality for patients with PJI may be considerably higher. Surgeons should be cognizant of the potentially fatal outcome of PJI and must emphasize the importance of infection control to reduce the risk of mortality