Anesthesia, General ; Coronavirus Infections ; prevention & control ; transmission ; Humans ; Infectious Disease Transmission, Patient-to-Professional ; prevention & control ; Occupational Exposure ; prevention & control ; Operating Rooms ; Otorhinolaryngologic Surgical Procedures ; Pandemics ; prevention & control ; Personal Protective Equipment ; classification ; Pneumonia, Viral ; prevention & control ; transmission ; Practice Guidelines as Topic

INTRODUCTIONLocal data on revision total knee arthroplasty (TKA) are limited. This study aims to assess the causes and outcomes of revision TKA in a single institution, with a 2-year follow-up.

MATERIALS AND METHODSA retrospective review of case records of patients who underwent revision TKA in 2008 and 2009 in the authors' institution was performed. Outcome was assessed using SF-36, Oxford knee score and Knee Society Clinical Rating System preoperatively, at 6 months and at 2 years' follow-up.

RESULTSForty-one patients (41 knees) were included in the study. Indications for revision were aseptic loosening in 13 (31.7%), mechanical wear/component failure in 10 (24.4%), infection in 9 (22.0%), malalignment in 4 (9.8%), instability in 3 (7.3%), periprosthetic fracture in 1 (2.4%) and persistent stiffness in 1 (2.4%). Significant improvements were seen postoperatively in all 3 instruments used to evaluate clinical outcome. These improvements were seen at 6 months after surgery, and were maintained through the 2-year follow-up period. There were no significant changes in all scores between 6 months and 2 years follow-up. There was 100% survivorship of the implants with no postoperative complications requiring surgical intervention.

CONCLUSIONIndications for revision TKA locally are similar to those in other large centres. Revision total knee arthroplasty results in significantly improved function and quality of life for patients, which is maintained over a 2-year follow-up period. In our series, we obtained 100% implant survivorship.

Aged ; Arthroplasty, Replacement, Knee ; Female ; Follow-Up Studies ; Humans ; Incidence ; Knee Prosthesis ; Male ; Middle Aged ; Osteoarthritis, Knee ; surgery ; Postoperative Complications ; epidemiology ; Prosthesis Failure ; Reoperation ; Retrospective Studies ; Singapore ; epidemiology ; Time Factors

INTRODUCTIONTotal knee arthroplasty (TKA) is one of the most successful orthopaedic procedures to date. It is estimated that over 130,000 of TKAs are performed in the United States every year. Whilst the procedure is safe, it nevertheless carries a risk of perioperative mortality and morbidity. This study aimed to report the mortality rate within 30 days after a TKA, as well as to assess the incidence of early postoperative morbidities.

MATERIALS AND METHODSWe reviewed a total of 2219 TKAs performed by multiple surgeons in our centre from 1998 to 2001. All mortalities within 30 days of a TKA were recorded. Morbidities such as infection, thromboembolic phenomenon, and any re-admissions within 30 days of operation or 15 days of discharge were recorded.

RESULTSThe mortality rate within 30 days of a TKA was 0.27% (6 of 2219 patients). The incidence of early postoperative infection was 1.8%, of which 1.44% were superficial and 0.36% were deep infections. There were 3 cases (0.13%) of pulmonary embolism and 22 cases (0.99%) of deep vein thrombosis.

CONCLUSIONSThe 30-day mortality rate, and the incidence of infection after TKA performed in our institution is comparable to other centres around the world, and further emphasises that TKA is a safe procedure. However, the small number of mortalities in this study does not allow us to identify a predominant cause of perioperative mortality.

Aged ; Aged, 80 and over ; Arthroplasty, Replacement, Knee ; adverse effects ; mortality ; Female ; Humans ; Incidence ; Male ; Middle Aged ; Mortality ; trends ; Patient Readmission ; Postoperative Complications ; Pulmonary Embolism ; Retrospective Studies ; Thromboembolism ; Treatment Failure ; Venous Thrombosis

INTRODUCTIONUp to 20% of patients who underwent total knee arthroplasty (TKA) reported dissatisfaction with surgical outcome. Despite the multiple studies looking into the factors contributing to patients' dissatisfaction, little research has been done to examine the subjective reasons and complaints patients have post-arthroplasty. This study aimed to look at an Asian patient population which underwent TKA and examine the factors contributing to patient dissatisfaction and the reasons they were dissatisfied with their surgery.

MATERIALS AND METHODSA total of 3069 TKAs were performed between January 2011 to April 2013 in a single institution. Preoperative and postoperative variables were prospectively captured, such as standardised knee scores, knee range of motion and patient satisfaction scores. These variables were then analysed with a multiple logistic regression model to determine the statistically significant factors that contribute to patients' satisfaction. Dissatisfied patients were individually interviewed to find the reasons for their unhappiness. Preoperative variables were then analysed to identify the statistically significant factors associated with these subjective complaints.

RESULTSMinimum duration of follow-up was 2 years, with an overall patient satisfaction rate of 91.3%. Preoperative variables contributing to patient dissatisfaction included female gender and better knee flexion. Postoperative variables included lesser improvement in knee flexion at 6 months postoperatively, as well as poorer scores in various validated knee scores at both 6 months and 2 years postoperatively. The top reason for dissatisfaction was pain. Weakness, another reason for patient dissatisfaction, had statistically significant preoperative predictors of increased age and poorer Short-Form 36 Physical Component Score.

CONCLUSIONAlthough TKA has an impressive patient satisfaction rate in this Asian population, factors contributing to postoperative dissatisfaction suggest a targeted group of patients would benefit from preoperative counselling. The top reason for postoperative dissatisfaction in the study was pain.

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.
Ankylosis ; Arthroplasty ; Arthroplasty, Replacement, Knee* ; Asian Continental Ancestry Group* ; Body Mass Index ; Humans ; Inpatients ; Knee* ; Length of Stay ; Patient Satisfaction* ; Rehabilitation ; Retrospective Studies

INTRODUCTIONThe use of robotics in total knee arthroplasty (TKA) has been shown to minimise human error, as well as improve the accuracy and precision of component implantation and mechanical axis alignment. The present study aimed to demonstrate that robot-assisted TKA using ROBODOC® is safe and capable of producing a consistent and accurate postoperative mechanical axis.

METHODSWe prospectively recruited 27 consecutive patients who underwent robot-assisted TKA between May and December 2012. Two patients were excluded from the study due to intraoperative technical problems with the robot. Long-leg radiography and computed tomography were performed prior to surgery, and used for mechanical axis measurements and component sizing. DigiMatch™ ROBODOC® Surgical System software version 4.3.6 (Curexo Technology Corp, Fremont, CA, USA) was used in all cases to perform bone cuts in accordance with the preoperative plan.

RESULTSThe postoperative coronal mechanical alignment was within 3 degrees, with a mean alignment of -0.4 ± 1.7 degrees, confirming the accuracy of the preoperative surgical plan and bone cuts. The mean operating time was 96 ± 15 min, and preoperative planning yielded 100% implant sizing accuracy.

CONCLUSIONRobotics has the potential to enable surgeons to consistently attain ideal postoperative alignment. The use of bone movement monitors and an integrated navigation system enhances the safety profile of ROBODOC® by minimising errors. However, the role of the surgeon in TKA is still vital, as the surgeon is ultimately in charge of planning the surgery, its execution and ensuring soft tissue balance during TKA.

Aged ; Arthroplasty, Replacement, Knee ; instrumentation ; Female ; Humans ; Knee Joint ; diagnostic imaging ; Male ; Middle Aged ; Prospective Studies ; Robotic Surgical Procedures ; instrumentation ; Tibia ; surgery ; Tomography, X-Ray Computed

INTRODUCTIONThe Singapore General Hospital Bone Bank, which exclusively stores femoral head allografts, relies on flash sterilisation to prevent allograft-related disease transmission and wound infection. However, intraosseous temperatures during autoclaving may be lower than required to eliminate human immunodeficiency virus, and hepatitis B and C viruses. The aim of this study is to determine the intraosseous temperatures of femoral head allografts during autoclaving and to assess the adequacy of autoclaving in preventing disease transmission.

METHODSSix femoral heads were acquired from patients who underwent hip arthroplasty. The specimens were divided into two groups. The first group underwent flash sterilisation with a sterilisation time of 4 min, while a longer sterilisation time of 22 min was used for the second group.

RESULTSThe highest core temperature in the first group was 130°C, while the core temperatures in the second group plateaued at 133°C for all allografts. In the first group, only smaller allografts maintained temperatures sufficient for the inactivation of the clinically relevant viral pathogens. In contrast, all allografts in the second group were terminally sterilised.

CONCLUSIONThere is an inverse correlation between the size of allografts and intraosseous temperatures achieved during autoclaving. Therefore, we recommend dividing large allografts into smaller pieces, in order to achieve intraosseous temperatures adequate for the elimination of transmissible pathogens during flash sterilisation. Allografts should not be terminally sterilised, as the resulting allografts will become unusable. Despite modern processing techniques, stringent donor selection remains vital in the effort to prevent allograft-related infections. Autoclaving is an economical and efficacious method of preventing allograft-related disease transmission.

Allografts ; Blood-Borne Pathogens ; Bone Transplantation ; instrumentation ; Disease Transmission, Infectious ; prevention & control ; Disinfection ; methods ; standards ; Equipment Contamination ; prevention & control ; Femur Head ; microbiology ; transplantation ; Humans ; Sterilization ; methods ; Temperature

BACKGROUND: This study was designed to evaluate predictors of good outcomes following medial unicompartmental knee arthroplasty (UKA) in Asian patients. METHODS: Registry data of patients who underwent primary unilateral medial UKA from 2006 to 2011 were collected. Outcomes studied were the Oxford Knee Score (OKS) and the Physical Component Score (PCS) of the Short Form 36 (SF-36) questionnaire. These outcome scores were collected prospectively, pre- and postoperatively up to 5 years. Good outcome was defined as an overall improvement in score greater than or equal to the minimal clinically important difference (MCID). The MCID for the OKS was 5 while the MCID for the PCS was 10. Regression analysis was used to identify predictors of good outcomes following medial UKA. RESULTS: Primary medial UKA was performed in 1,075 patients. Higher (poorer) preoperative OKS (odds ratio [OR], 1.27; p < 0.001), lower (poorer) preoperative PCS (OR, 1.08; p < 0.001), lower (poorer) preoperative Knee Society Knee Score (KSKS; OR, 1.02; p < 0.001) and higher (better) preoperative SF-36 Mental Component Score (MCS; OR, 1.02; p < 0.001) were significant predictors of good outcomes. CONCLUSIONS: Patients with poorer OKS, PCS and KSKS and better SF-36 MCS preoperatively tended to achieve good outcomes by the MCID criterion at 5 years following the index surgery.
Arthroplasty ; Arthroplasty, Replacement, Knee* ; Asia ; Asian Continental Ancestry Group* ; Humans ; Knee ; Osteoarthritis ; Prospective Studies ; Registries

INTRODUCTIONThere is considerable controversy regarding the best method to prevent venous thromboembolism. In 2008, the American College of Chest Physicians (ACCP) published specific guidelines recommending the use of ow-molecular-weight heparin or warfarin, and a target international normalised ratio of 2.0-3.0 for a duration of at least 7-10 days, after elective knee arthroplasties. Many orthopaedic surgeons believe that these recommendations are biased toward reducing deep venous thrombosis (DVT), but neglect the implicated possibility of a higher incidence of wound complications. In order to enable an objective evaluation of the fit of the ACCP recommendations to the needs of our local cohort of patients, we aimed to look at the incidence of DVT in our local population.

METHODSThis study was a prospective observational study involving existing local patients in Singapore General Hospital, Singapore, who underwent total knee arthroplasty (TKA) and were on a short course of chemothromboprophylaxis (< 7 days) after the operation. The incidence of DVT in patients was evaluated using DVT imaging 4-6 days after the operation and at one month after the operation.

RESULTSIn our study cohort, the prevalence of DVT during the period between postoperative Days 4 and 6 was 12% (11% were distal DVT and 1% was proximal DVT). Only 9% of the patients had DVT one month after the operation. Using chi-square analysis, we found that there was no significant increase in the number of DVT and pulmonary embolism cases 4-6 days and 1 month after the operation (p > 0.05).

CONCLUSIONContrary to the ACCP guidelines, a short course of chemothromboprophylaxis post TKA, lasting no more than 7 days, is safe and adequate in the low-risk Asian population.

Adult ; Aged ; Aged, 80 and over ; Anticoagulants ; therapeutic use ; Arthroplasty, Replacement, Knee ; adverse effects ; Drug Administration Schedule ; Female ; Follow-Up Studies ; Heparin, Low-Molecular-Weight ; therapeutic use ; Humans ; Incidence ; Male ; Middle Aged ; Osteoarthritis, Knee ; surgery ; Postoperative Complications ; Prognosis ; Prospective Studies ; Singapore ; epidemiology ; Treatment Outcome ; Venous Thrombosis ; epidemiology ; etiology ; prevention & control ; Warfarin ; therapeutic use

BACKGROUND: To date, there is no study comparing outcomes between post-total knee replacement genu recurvatum and fixed flexion. This study aims to provide data that will help in deciding which side to err on when neutral extension is not achieved. METHODS: A prospective cohort study of primary total knee arthroplasties was performed, which compared the 6-month and 2-year clinical outcomes between fixed flexion and genu recurvatum deformities at 6 months. RESULTS: At 6 months, knees in genu recurvatum did better than knees in fixed flexion deformity in terms of knee flexion. However, at 2 years, knees in fixed flexion deformity did better in terms of knee scores and showed better improvement in the degree of deformity. CONCLUSIONS: We conclude that it is better to err on the side of fixed flexion deformity if neutral alignment cannot be achieved.
Aged ; Arthroplasty, Replacement, Knee/*adverse effects/*statistics & numerical data ; Female ; Humans ; Knee Joint/*physiopathology/*surgery ; Male ; Middle Aged ; Prospective Studies ; Range of Motion, Articular ; Treatment Outcome