Patellar reconstruction in primary total knee arthroplasty using bone chips from routine cuts:A case report and review of literature

BACKGROUND Total patellectomy is currently reserved for exceptional cases,such as recalcitrant patellofemoral instability and comminuted fractures,due to its demonstrated negative impact on knee biomechanics.Therefore,managing patellectomy is crucial to mitigate its inherent deleterious effects.Various techniques have been described,including autologous or allogeneic bone grafts for reconstruction and soft tissue realignment to enhance the extensor mechanism.CASE SUMMARY A 73-year-old male underwent a patellectomy due to a comminuted fracture,subsequently developing osteoarthritis and experiencing a decline in functional status.Concurrent with total knee replacement,we conducted a patellar reconstruction,incorporating routine bone cuts and utilizing bone chips to fashion a new patella.This intervention resulted in the restoration of full extension and improvement of knee function.CONCLUSION Patellar reconstruction demonstrates benefits on knee mechanics and stabilization,contributing to enhanced outcomes and satisfaction following knee replacement.We present an affordable technique for managing patellectomized patients undergoing total knee replacement.

Meta-analysis of factors influencing anterior knee pain after total knee arthroplasty

BACKGROUND Total knee arthroplasty(TKA)is a mature procedure recommended for correcting knee osteoarthritis deformity,relieving pain,and restoring normal biomechanics.Although TKA is a successful and cost-effective procedure,patient dissatisfaction is as high as 50%.Knee pain after TKA is a significant cause of patient dissatisfaction;the most common location for residual pain is the anterior region.Between 4%and 40%of patients have anterior knee pain(AKP).AIM To investigate the effect of various TKA procedures on postoperative AKP.METHODS We searched PubMed,EMBASE,and Cochrane from January 2000 to September 2022.Randomized controlled trials with one intervention in the experimental group and no corresponding intervention(or other interventions)in the control group were collected.Two researchers independently read the title and abstract of the studies,preliminarily screened the articles,and read the full text in detail according to the selection criteria.Conflicts were resolved by consultation with a third researcher.And relevant data from the included studies were extracted and analyzed using Review Manager 5.4 software.RESULTS There were 25 randomized controlled trials;13 were comparative studies with or without patellar resurfacing.The meta-analysis showed no significant difference between the experimental and control groups(P=0.61).Six studies were comparative studies of circumpatellar denervation vs non-denervation,divided into three subgroups for meta-analysis.The two-subgroup meta-analysis showed no significant difference between the experimental and the control groups(P=0.31,P=0.50).One subgroup meta-analysis showed a significant difference between the experimental and control groups(P=0.001).Two studies compared fixed-bearing TKA and mobile-bearing TKA;the results meta-analysis showed no significant difference between the experimental and control groups(P=0.630).Two studies compared lateral retinacular release vs non-release;the meta-analysis showed a significant difference between the experimental and control groups(P=0.002);two other studies compared other factors.CONCLUSION Patellar resurfacing,mobile-bearing TKA,and fixed-bearing TKA do not reduce the incidence of AKP.Lateral retinacular release can reduce AKP;however,whether circumpatellar denervation can reduce AKP is controversial.

Self-management of osteoarthritis while waiting for total knee arthroplasty during the COVID-19 pandemic among older Malaysians

BACKGROUND The study sought to understand the self-management strategies used by patients during the postponement of their total knee arthroplasty(TKA)procedure,as well as the associations between the length of waiting time,pain,and physical frailty and function.The study focused on individuals aged 50 years and above,as they are known to be more vulnerable to the negative impacts of delayed elective surgery and rehabilitation.This study hypothesizes that delayed TKR due to coronavirus disease 2019(COVID-19)will bear negative effect in self-management,pain,and physical frailty and function in older adults.AIM To investigate the effects of COVID-19 pandemic on self-management,pain,and physical function in older adults awaiting TKA in Malaysia.METHODS This cross-sectional study has the data of participants,who matched the criteria and scheduled for TKA for the first time,extracted from the TKA registry in the Department of Orthopaedics and Traumatology,Hospital Canselor Tuanku Mukhriz.Data on pain status,and self-management,physical frailty,and instrumental activities daily living were also collected.Multiple linear regression analysis with a significant level of 0.05 was used to identify the association between waiting time and pain on physical frailty and functional performance.RESULTS Out of 180 had deferred TKA,50%of them aged 50 years old and above,80%were women with ethnic distribution Malay(66%),Chinese(22%),Indian(10%),and others(2%)respectively.Ninety-two percent of the participants took medication to manage their pain during the waiting time,while 10%used herbs and traditional supplements,and 68%did exercises as part of their osteoarthritis(OA)self-management.Thirty-six participants were found to have physical frailty(strength,assistance with walking,rising from a chair,climbing stairs,and falls questionnaire score>4)which accounted for 72%.Increased pain was associated with physical frailty with odds ratio,odds ratio(95%confidence interval):1.46(1.04-2.05).This association remained significant even after the adjustment according to age and self-management.CONCLUSION While deferring TKA during a pandemic is unavoidable,patient monitoring for OA treatment during the waiting period is important in reducing physical frailty,ensuring the older patients’independence.

Comparison of clinical outcomes between total hip replacement and total knee replacement

BACKGROUND Total hip replacements(THR)and total knee replacements(TKR)are effective treatments for severe osteoarthritis(OA).Some studies suggest clinical outcomes following THR are superior to TKR,the reason for which remains unknown.This study compares clinical outcomes between THR and TKR.AIM To compare the clinic outcomes of THR anad TKR using a comprehensive range of patient reported outcome measures(PROMs).METHODS A prospective longitudinal observational study of patients with OA undergoing THR and TKR were evaluated using a comprehensive range of generic and joint specific PROMs pre-and post-operatively.RESULTS A total of 131 patients were included in the study which comprised the THR group(68 patients)and the TKR group(63 patients).Both groups demonstrated significant post-operative improvements in all PROM scores(P<0.001).There were no significant differences in post-operative PROM scores between the two groups:Hip and Knee Osteoarthritis Outcome scores(P=0.140),Western Ontario and McMaster Universities Osteoarthritis Index pain(P=0.297)stiffness(P=0.309)and function(P=0.945),Oxford Hip and Knee Score(P=0.076),EuroQol-5D index(P=0.386)and Short-Form 12-item survey physical component score(P=0.106).Subgroup analyses showed no significant difference(P>0.05)between cruciate retaining and posterior stabilised prostheses in the TKR group and no significant difference(P>0.05)between cemented and uncemented fixation in the THR group.Obese patients had poorer outcomes following TKR but did not significantly influence the outcome following THR.CONCLUSION Contrary to some literature,THR and TKR are equally efficacious in alleviating the pain and disability of OA when assessed using a comprehensive range of PROMs.The varying knee prosthesis types and hip fixation techniques did not significantly influence clinical outcome.Obesity had a greater influence on the outcome following TKR than that of THR.

Effect of body mass index on functional outcome in primary total knee arthroplasty——a single institution analysis of 2180 primary total knee replacements

AIM To evaluate the effect of body mass index(BMI) on short-term functional outcome and complications in primary total knee arthroplasty. METHODS All patients undergoing primary total knee arthroplasty at a single institution between 2007 and 2013 were identified from a prospective arthroplasty database. 2180 patients were included in the study. Age, gender, BMI, pre- and post-operative functional scores [Western Ontario and Mc Master University Arthritis Index(WOMAC) and SF-36], complications and revision rate were recorded. Patients were grouped according to the WHO BMI classification. The functional outcome of the normal weight cohort(BMI < 25) was compared to the overweight and obese(BMI ≥ 25) cohort. A separate sub-group analysis was performed comparing all five WHO BMI groups; Normal weight, overweight, class 1 obese, class 2 obese and class 3 obese.RESULTS With a mean age of 67.89(28-92), 2180 primary total knee replacements were included. 64.36%(1403) were female. The mean BMI was 31.86(18-52). Ninty-three percent of patients were either overweight or obese. Mean follow-up 19.33 mo(6-60 mo). There was no significant difference in pre or post-operative WOMAC score in the normal weight(BMI < 25) cohort compared to patients with a BMI ≥ 25(P > 0.05). Sub-group analysis revealed significantly worse WOMAC scores in class 2 obese 30.80 compared to overweight 25.80(P < 0.01) and class 1 obese 25.50(P < 0.01). Similarly, there were significantly worse SF-36 scores in class 2 obese 58.16 compared to overweight 63.93(P < 0.01) and class 1 obese 63.65(P < 0.01) There were 32(1.47%) superficial infections, 9(0.41%) deep infections and 19(0.87%) revisions overall with no complications or revisions in the normal weight cohort(BMI < 25).CONCLUSION Post-operative functional outcome was not influenced by BMI comparing normal weight individuals with BMI > 25. Patients should not be denied total knee arthroplasty based solely on weight alone.

The clinical comparison of simultaneous bilateral total knee arthroplasty in treatment of osteoarthritis

Objective： To evaluate the risk and efficacy of simultaneous bilateral total knee arthroplasty（TKA） in treatment of osteoarthritis when compared with sequential bilateral TKA and unilateral TKA. Methods：A retrospective analysis was performed on 162 patients who underwent TKA from 2003 to 2006. The analyses were adjusted for demographics, preexisting medical conditions, and osteoar- thrifts diagnosis. Results：Patients undergoing simultaneous bilateral TKA had significantly lower amounts of blood loss, shorter surgical time, shorter hospitalization time, less hospital charges and lower rates of perioperative complications compared with patients undergoing sequential bilateral TKA. No significant difference was found with regard to postoperative complications between the simultaneous bilateral and the unilateral TKA groups. Patient＇ s knee range of motion and the postoperative Hospital for Special Surgery scores（HSS） were similar for the three groups. Conclusion：When there are adequate indications for bilateral TKA, simultaneous bilateral TKA is beneficial to patients compared with sequential bilateral or unilateral TKA.

The Clinical Characteristics of Combined Deep Vein Thrombosis Prophylaxis of Rivaroxaban and Mechanical Therapy after Total Knee Replacement Arthroplasty

Purpose: To investigate the clinical characteristics of combined prophylaxis of rivaroxaban (Xarelto?) and mechanical therapy (foot sole pump, antiembolism stocking) after total knee replacement arthroplasty, for prevention of deep vein thrombosis (DVT). Materials and Methods: The subjects of this study were 110 patients who underwent total knee replacement arthroplasty (TKA) between November 2011 and May 2012, and were prospectively evaluated. They consisted of 13 men (11.8%) and 97 women (88.2%) with the mean age of 68.7 years (±7.9). All of the patients received 10 mg of rivaroxaban once daily for 14 days from Day 1 postoperatively, and used an intermittent pneumatic compression (IPC) pump and compression stockings immediately after the operation. To determine the presence of postoperative DVT, clinical symptoms examination, D-dimer test, color Doppler ultrasound imaging were performed to analyze the risk factors of DVT events. Results: There were a total of 13 patients (11.8%) with DVT in the distal lower limbs among the entire 110 patients. At Day 4 after the operation, a statistically significant difference was seen only in femoral swelling of several clinical symptoms between DVT group and non-DVT group (p = 0.043). D-dimer tests showed no statistically significant difference between the two groups, however with the boundary value of 0.3 mg/L, diagnostic sensitivity, specificity, positive predictability and negative predictability were equivalent to 100%, 8.2%, 12.7% and 100%, respectively. There was no significant difference between the two groups in terms of well-known risk factors including age, gender, obesity, hypertension, diabetes, smoking, and anesthesia method, and no case of pulmonary embolism was observed. Conclusion: A combination of pharmacological therapy (rivaroxaban, Xarelto?) and mechanical therapy (foot sole pump system) after TKA is considered effective for DVT prevention.

Surgical treatment outcome of painful traumatic neuroma of the infrapatellar branch of the saphenous nerve during total knee arthroplasty

BACKGROUND Development of infrapatellar saphenous neuroma(ISN)is a well-recognized reason for knee pain following total knee arthroplasty(TKA).So far,very few studies have addressed the development of painful ISN after TKA and its impact on functional outcome and patient satisfaction.AIM To present the results of surgical treatment for ISN after primary TKA,the level of pain relief,and the improvement of knee motion and function.METHODS Fifteen patients(13 women,2 men)with persistent medial pain for more than six months after primary TKA,due to osteoarthritis,underwent surgical excision of ISN.ISN diagnosis was confirmed with the presence of Tinel’s sign along the course of the infrapatellar branch of the saphenous nerve and with pain relief after selective nerve block using local anesthetic.Component loosening,malalignment,instability and infection were excluded systematically in all patients as a source of pain.Pain relief in terms of visual analog scale(VAS),active knee range of motion(ROM),and the Knee Society Score(KSS)for pain and function were evaluated preoperatively and at least six months postoperatively.RESULTS The mean patients’age was 71.3±5.4 years old.The mean interval between TKA and neuroma excision was 10 mo(range,6 to 14 mo),while the mean follow-up was 8 mo(range:6 to 11 mo).All 15 patients experienced almost complete immediate pain relief and resolution of allodynia and hyperesthesia after surgery.Pain on the VAS scale improved from 8.6±1.3 preoperatively to 0.8±0.9 at the final follow-up(P=0.001).KSS pain and function scores were improved from 49.3±5.9 and 62.7±12.8 before surgery to 91.8±4.2 and 75.3±11.3 after surgery,respectively(P=0.001 and P=0.015).Active knee ROM was also increased postoperatively from 96±4 to 105±6 degrees(P=0.001).There were no complications and no further operations required.CONCLUSION ISN should be considered a potential cause of persistent pain following TKA.Neuroma excision not only provides immediate pain relief and resolution of symptoms but may also improve the knee range of motion.

Early Clinical and Functional Outcome of Primary Total Knee Replacement with Posterior Cruciate Substituting Prosthesis for Primary Knee Osteoarthritis Using 2011 Knee Society Score

Background: Primary knee Osteoarthritis (OA) is the commonest articular disease in middle age and elderly people. Primary total knee replacement (TKR) is a known world-wide standard and definitive treatment of primary knee OA following failed adequate non-operative management. It is of clinical importance to assess the clinical and functional outcome of TKR to prognosticate the severity of primary knee OA. The new (2011) knee society scoring system (nKSS) is both surgeons and patients’ assessment tool for the treatment outcome of TKR. Study Design: Prospective interventional analytical study. Aim and Objective: The aim of the study was to determine early clinical and functional outcome of primary total knee replacement in patients with primary knee osteoarthritis using nKSS. The objectives were: 1) To determine the pre-operative nKSS and post operative nKSS;2) To determine relationships between pre-operative nKSS and post operative nKSS at 6 weeks, 3, 6, 9 and 12 months;3) To determine the complication rates in patients undergoing primary TKR in the study centre. Methods: A prospective interventional study of 59 patients aged 51 to 70 years who had 67 Total Knee Replacements (TKRs) participated in the study between November 2015 to June 2018 at National Orthopaedics Hospital, Lagos, Nigeria. Patients’ sociodemographic data, pre-operative and post-operative nKSS system were recorded at 6 weeks, 3, 6, 9 and 12 months during follow up. The data were analyzed using Statistical Package for Social Science (SPSS). Results: There were 41 females and 18 males (M:F = 1:2.3). There were total of 67 TKRs with 31 right TKRs, 20 left TKRs and 8 staged bilateral TKRs. The participants’ age ranged from 51 to 70 years with the mean age of 59.5 (±8.5) years. Four patients did not complete the study due to various reasons. The remaining 55 participants completed the study period with progressive improvement of their post-operative nKSS at 6 weeks, 3, 6, 9 and 12 months post-operatively when compared with pre-operative nKSS (P value 0.5). Conclusion: This study revealed improved early clinical and functional outcome of primary total knee replacement in primary knee osteoarthritis using nKSS in all the studied patients. There is no significant negative effect of lower pre-operative nKSS (and its components) on the post-operative nKSS outcome.

New treatment of patellar instability after total knee arthroplasty: A case report and review of literature

BACKGROUND Patellar instability is an uncommon complication after total knee arthroplasty(TKA).Partial lateral patella facetectomy(LPF)with lateral retinaculum release treatment of patellar instability is rarely reported.CASE SUMMARY We present a case of patellar instability 8 mo after primary TKA.Treatment of this complication was adapted to address the cause of the dislocation.To eliminate patellar instability,we restored the vastus medialis and performed LPF with lateral retinaculum release.We achieved normal patellar tracking.Clinical and radiographic evaluations at the 1-year postoperative follow-up were satisfactory.CONCLUSION LPF with lateral retinaculum release represents a promising option to restore central patellar tracking in patients with patellar instability after TKA in cases without component malposition.

A Case of Simultaneous Total Knee Arthroplasty in Congenital Dislocation of the Patella

The gonarthrosis with congenital dislocation of the patella is rare condition. This paper will report about total knee arthroplasty (TKA) for the valgus knee with bilateral congenital dislocation of the patella. A 52-year-old woman presented to our hospital with progressive pain in bilateral knees. Both knee showed severe valgus deformity and lateral dislocation of the patella. Anteroposterior weight-bearing radiographs showed osteoarthritic changes in the lateral compartment with 7 valgus deformity at the right and 15 at the left. A bilateral TKA with cruciate retained components (NAKASHIMA FINE) was performed. Good tracking of the patella was achieved by using a lateral parapatellar approach and vastus medialis plication. There are no normative guidelines of operative procedure about TKA for osteoarthritis of valgus knee with congenital dislocation of the patella. With some referencing to current literature, strategies to good patella tracking are discussed.

New Classification and Visual Analysis of the Patella Cartilage during Total Knee Replacement

Objective: The aim of this prospective study is to evaluate how much damage the patellar cartilage presents during a total knee replacement. Methods: The damage of the articular patellar surface was analysed by visual inspection and photographs in 354 primary total knee replacements. The authors graded the degree of cartilage lesion in five groups. The cartilage status was analyzed and correlated with age, gender, side, body mass index (BMI), Kellgren-Lawrence radiographic scale and axial deviation. Results: After statistical analysis, we concluded: there was no evidence of an association between patellar arthrosis and age gender, side, weight and deformity. Conclusions: Articular cartilage was damaged in all 354 knees. Important subchondral bone exposure occurred in 274 knees (77.4%). Obese patients had more severe patellar osteoarthritis.

Anterior knee pain following primary total knee arthroplasty

Despite improvements in technique and technology for total knee arthroplasty(TKA),anterior knee pain impacts patient outcomes and satisfaction.Addressing the prosthetic and surgical technique related causes of pain after TKA,specifically as it relates to anterior knee pain,can aid surgeons in addressing these issues with their patients.Design features of the femoral and patellar components which have been reported as pain generators include: Improper femoral as well as patellar component sizing or designs that result in patellofemoral stuffing; a shortened trochlear groove distance from the flange to the intercondylar box; and then surgical technique related issues resulting in: Lateral patellar facet syndrome; overstuffed patella/flange combination; asymmetric patellar resurfacing,improper transverse plane component rotation resulting in patellar subluxation/tilt.Any design consideration that allows impingement of extensor mechanism anatomical elements has the possibility of impacting outcome by becoming a pain generator.As the number of TKA procedures continues to increase,it is increasingly critical to develop improved,evidence based prostheses that maximize function and patient satisfaction while minimizing pain and other complications.

Perioperative blood management strategies for patients undergoing total knee replacement:Where do we stand now?

Total knee replacement(TKR) is one of the most common surgeries over the last decade. Patients undergoing TKR are at high risk for postoperative anemia and furthermore for allogeneic blood transfusions(ABT). Complications associated with ABT including chills, rigor, fever, dyspnea, light-headedness should be early recognized in order to lead to a better prognosis. Therefore, perioperative blood management program should be adopted with main aim to reduce the risk of blood transfusion while maximizing hemoglobin simultaneously. Many blood conservation strategies have been attempted including preoperative autologous blood donation, acute normovolemic haemodilution, autologous blood transfusion, intraoperative cell saver, drain clamping, pneumatic tourniquet application, and the use of tranexamic acid. For practical and clinical reasons we will try to classify these strategies in three main stages/pillars: Pre-operative optimization, intra-operative and post-operative protocols. The aim of this work is review the strategies currently in use and reports our experience regarding the perioperative blood management strategies in TKR.

Total knee arthroplasty for treatment of post-traumatic arthritis: Systematic review

AIM To review and report functional outcomes, complications,and survivorship associated with total knee arthroplasty(TKA) in the treatment of post-traumatic arthritis(PTA).METHODS We conducted a systematic review according to the PRISMA guidelines. We searched PubMed, Cochrane Library, and SCOPUS in December 2015 for Englishlanguage clinical research studies, both prospective and retrospective, examining the use of TKA for the treatment of PTA. All relevant articles were accessed in full. The manual search included references of retrieved articles.We extracted data on patients' demographics and clinical outcomes, including preoperative diagnosis and pre- and post-operative functional scores. We summarized the data and reported the results in tables and text.RESULTS Sixteen studies, four prospective and ten retrospective,examined patients who underwent TKA for PTA due to fractures of the proximal tibia, patella, and/or distal femur. Eleven studies utilized the Knee Society Scores criteria to assess functional outcomes. All studies utilizing these criteria reported an improvement in functional and knee scores of patients following TKA. Further, studies reported an increased range of motion(ROM) and reduction of pain following surgery. The most commonly reported complications with TKA included infection, stiffness, wound complications, intraoperative rupture of tendons, and osteolysis/polyethylene wear. The overwhelming majority of these complications occurred within the first two years following surgery. Six studies examined the survivorship of TKA with subsequent revision for any reason as an endpoint. Compared to patients with osteoarthritis, patients with PTA required more revisions, the majority for polyethylene wear.CONCLUSION Although associated with higher complication rates,TKA is an effective treatment for PTA, as it improves ROM, pain and functional outcomes.

Common controversies in total knee replacement surgery: Current evidence

Total knee replacement(TKR) is a widely used operation that has radically improved the quality of life of millions of people during the last few decades. However, some technical details, concerning the surgical procedure and the rehabilitation following total knee arthroplasty, are still a matter of a strong debate. In this review of the literature, we have included the best evidence available of the last decade, in an effort to shed light on some of the most controversial subjects related to TKR surgery. Posterior-stabilized or cruciate-retaining prosthesis? To use a tourniquet during operation or not? Do patients need continuous passive motion for their post-surgery rehabilitation? To resurface patella or not? These are some of the most controversial topics that until now have been persistent dilemmas for the orthopedic surgeon. Results of this systematic review of the literature are highly controversial. These conflicting results are an indication that larger and more well conducted high quality trials are needed in order to gain more secure answers. At the same time, it is becoming apparent that a meticulous operative technique, respecting the soft tissue envelope and knowing the principles of alignment and soft tissue balancing, aresome of the parameters that might contribute more to achieving the optimal results for the patients.

Physical activity after total knee arthroplasty: A critical review

Total knee arthroplasty(TKA) is the most commonly performed elective surgery in the United States. TKA typically improves functional performance and reduces pain associated with knee osteoarthritis. Little is known about the influence of TKA on overall physical activity levels. Physical activity, defined as "any bodily movement produced by skeletal muscles that results in energy expenditure", confers many health benefits but typically decreases with endstage osteoarthritis. The purpose of this review is to describe the potential benefits(metabolic, functional, and orthopedic) of physical activity to patients undergoing TKA, present results from recent studies aimed to determine the effect of TKA on physical activity, and discuss potential sources of variability and conflicting results for physical activity outcomes. Several studies utilizing self-reported outcomes indicate that patients perceive themselves to be more physically active after TKA than they were before surgery. Accelerometry-based outcomes indicate that physical activity for patients after TKA remains at or below pre-surgical levels. Several different factors likely contributed to these variable results, including the use of different instruments, duration of follow-up, and characteristics of the subjects studied. Comparison to norms, however, suggests that daily physical activity for patients following TKA may fall short of healthy agematched controls. We propose that further study of the relationship between TKA and physical activity needs to be performed using accelerometry-based outcome measures at multiple post-surgical time points.

Total knee arthroplasty:Effect of obesity and other patients' characteristics on operative duration and outcome

AIM: To examine the effects of patients' characteristics mainly obesity on operative duration and other outcomemeasures of knee arthroplasty. METHODS: This is a retrospective chart review of 204 patients who had knee arthroplasty within the past five years(2007-2011) at King Abdulaziz Medical City in Riyadh, Kingdom of Saudi Arabia. The data collection form was developed utilizing the literature review to gather all the needed variables. Data were gathered from admission notes, nursing notes, operative reports and discharge summaries.RESULTS: A feasible sample of 204 patients were included in the study. Of those patients, 155(76%) were females. The mean age was 70.1 years for males(SD ± 9.4) and 62.7 years(SD ± 8) for females. Regarding the type of total knee replacement(TKR), 163(79.9%) patients had unilateral TKR and 41(20.1%) had bilateral TKR. Nine patients(4.4%) had a normal body mass index(BMI)(18.5 to < 25). Overweight patients(BMI 25 to < 30) represented 18.1%. Obesity class Ⅰ(BMI 30 to < 35) and obesity class Ⅱ(BMI from 35 to < 40) were present in 23% and 29.9% of the patients, respectively. Morbid obesity(BMI greater than 40) was present in 24.5%. The mean duration of surgery was 126.3 min(SD ± 30.8) for unilateral TKR and 216.6 min(SD ± 55.4) for bilateral TKR.The mean length of stay in the hospital was 12 d(SD ± 4.9). The complications that patients had after the operation included 2 patients(1%) who developed deep venous thrombosis, 2 patients(1%) developed surgical wound infections and none had pulmonary embolism. Patients' characteristics(including age, gender, BMI and co-morbidities) did not have an effect on the operative duration of knee replacement nor the length of hospital stay. CONCLUSION: Our study shows that obesity and other patients' characteristics do not have effect on the operative duration nor the length of hospital stay following TKR.

Muscle force and movement variability before and after total knee arthroplasty: A review

Variability in muscle force output and movement variability are important aspects of identifying individuals with mobility deficits, central nervous system impairments, and future risk of falling. This has been investigated in elderly healthy and impaired adults, as well as in adults with osteoarthritis(OA), but the question of whether the same correlations also apply to those who have undergone a surgical intervention such as total knee arthroplasty(TKA) is still being investigated. While there is a growing body of literature identifying potential rehabilitation targets for individuals who have undergone TKA, it is important to first understand the underlying post-operative impairments to more efficiently target functional deficits that may lead to improvedlong-term outcomes. The purpose of this article is to review the potential role of muscle force output and movement variability in TKA recipients. The narrative review relies on existing literature in elderly healthy and impaired individuals, as well as in those with OA before and following TKA. The variables that may predict longterm functional abilities and deficits are discussed in the context of existing literature in healthy older adults and older adults with OA and following TKA, as well as the role future research in this field may play in providing evidence-based data for improved rehabilitation targets.

Socio-demographic factors impact time to discharge following total knee arthroplasty

AIM To determine social, logistical and demographic factors that influence time to discharge in a short stay pathway(SSP) by following total knee arthroplasty(TKA). METHODS The study included primary TKA's performed in a highvolume arthroplasty center from January 2016 through December 2016. Potential variables associated with increased hospital length of stay(LOS) were obtained from patient medical records. These included age, gender, race, zip code, body mass index(BMI), number of pre-operative medications used, number of narcotic medications used, number of patient reported allergies(PRA), simultaneous bilateral surgery, tobacco use, marital status, living arrangements, distance traveled for surgery, employment history, surgical day of the week, procedure end time and whether the surgery was performed during a major holiday week. Multivariate step-wise regression determined the impact of social, logistical and demographic factors on LOS. RESULTS Eight hundred and six consecutive primary SSP TKA's were included in this study. Patients were discharged at a median of 49 h(post-operative day two). The following factors increased LOS: Simultaneous bilateral TKA [46.1 h longer(P < 0.001)], female gender [4.3 h longer(P = 0.012)], age [3.5 h longer per ten-year increase in age(P < 0.001)], patient-reported allergies [1.1 h longer per allergy reported(P = 0.005)], later procedure endtimes [0.8 h longer per hour increase in end-time(P = 0.004)] and Black or African American patients [6.1 h longer(P = 0.047)]. Decreased LOS was found in married patients [4.8 h shorter(P = 0.011)] and TKA's performed during holiday weeks [9.4 h shorter(P = 0.011)]. Non-significant factors included: BMI, median income, patient's living arrangement, smoking status, number of medications taken, use of pre-operative pain medications, distance traveled to hospital, and the day of surgery. CONCLUSION The cost of TKA is dependent upon LOS, which is affected by multiple factors. The clinical care team should acknowledge socio-demographic factors to optimize LOS.