Incidence of Venous Thromboembolism after Primary Total Hip Arthroplasty with Mechanical Prophylaxis in Hong Kong Chinese.

Purpose: The incidence of deep vein thrombosis (DVT) following total hip arthroplasty (THA) without chemoprophylaxis could be as high as 50% in Caucasians. However, according to several subsequent studies, the incidence of venous thromboembolic events (VTE) in Asians was much lower. The routine use of chemoprophylaxis, which could potentially cause increased bleeding, infection, and wound complications, has been questioned in low-incidence populations. The objective of this study is to determine the incidence of VTE after primary THA without chemoprophylaxis in an Asian population using a fast-track rehabilitation protocol and to verify the safety profile for use of 'mechanical prophylaxis alone' in patients with standard risk of VTE. Materials and Methods: This is a retrospective cohort study of 542 Hong Kong Chinese patients who underwent primary THA without chemoprophylaxis. All patients received intermittent pneumatic compression and graduated compression stockings as mechanical prophylaxis. Multimodal pain management was applied in order to facilitate early mobilisation. Routine duplex ultrasonography was performed between the fourth and seventh postoperative day for detection of proximal DVT. Results: All patients were Chinese (mean age, 63.0±11.9 years). Six patients developed proximal DVT (incidence rate, 1.1%). None of the patients had symptomatic or fatal pulmonary embolism. Conclusion: The incidence of VTE after primary THA without chemical prophylaxis can be low in Asian populations when following a fast-track rehabilitation protocol. Mechanical prophylaxis alone can be regarded as a reasonably safe practice in terms of a balanced benefit-to-risk ratio for Asian patients with standard risk of VTE.

Cross-Cultural Adaptation and Psychometric Properties of the Chinese Version of the Knee Osteoarthritis Fears and Beliefs Questionnaire.

This study aimed to adapt and validate the Knee Osteoarthritis Fears and Beliefs Questionnaire (KOFBeQ) for Chinese patients, thereby advancing the understanding of fear-avoidance behaviors. Adopting a cross-sectional design, data were collected for 241 subjects (78.8% women; mean age 68.0 ± 7.8 years) across various healthcare settings in Hong Kong. Exploratory factor analysis resulted in an 11-item questionnaire with three distinct subscales, covering fears and beliefs related to physicians and disease (six items), daily living activities (three items), and sports and leisure activities (two items). The overall Cronbach's α coefficient was 0.86, indicating strong internal consistency. The questionnaire exhibited favorable convergent validity. Confirmatory factor analyses confirmed a good model fit. Test-retest reliability analysis indicated a high intraclass correlation coefficient of 0.93 (95% confidence interval: 0.88, 0.96), and a Bland-Altman plot revealed a slight bias in two measurements (0.97 [0.19]) without a systematic trend. The adapted Chinese version of the KOFBeQ demonstrated robust psychometric properties in terms of validity and reliability, providing an effective tool for surveying Chinese patients with knee osteoarthritis. These findings offer valuable insights for clinicians and patients, aiding in informed decision-making and improved rehabilitation strategies.

Mid-term survivorship of fixed bearing unicondylar knee arthroplasty with no exclusion of early PFJ arthritis or ACL deficiency: Analysis of clinical and radiological predictors.

PURPOSE: Fixed bearing (FB) UKA constituted 63.7% of unicondylar knee arthroplasties in 2020 Australian Registry with the longest UKA survivorship. The significance of patellofemoral joint (PFJ) arthritis, ACL deficiency, post-operative anteromedial pain, radiosclerosis or radiolucency on survivorship of FB UKA is not established. The aim of this study was to analyze the medium-term survivorship of fixed-bearing UKA with no exclusion of PFJ OA and ACL deficiency. Predictors for failure were analyzed. METHODS: FB UKA performed in 2011-17 were reviewed. Cases with PFJ OA or ACL deficiency were not excluded. The effect on survivorship by ACL deficiency, PFJ arthritis, post-operative anteromedial pain and radiological abnormalities were analyzed. RESULTS: There were 96 UKA with follow-up time of 66 ± 18 months (27-98). The mean age was 70 ± 9 years, BMI 25.8 ± 2.6 kg/m2. Alignment was varus 9° ± 4° pre-operatively and varus 3° ± 3° post-operatively. There were four revisions (4.2%) and 4 deaths (4.2%). Reasons for revisions were loosening (n = 1), persistent pain (n = 2) and lateral compartment disease (n = 1). Estimated survival at 8.3 years was 94.7% (95% CI 91.6-97.7). BMI ≥30 was found to be a significant predictor for failure. The incidence of radiographic abnormalities was 75% for PFJ arthritis, 39% for tibial tray overhang, 14% for radiolucency or radiosclerosis, 5% for ACL deficiency and 5% for edge loading respectively but they were not significantly associated with lower survivorship or anteromedial knee pain. The presence of anteromedial pain after surgery in 36.5% was also not significantly associated with survivorship. CONCLUSION: FB UKA with no exclusion of early PFJ arthritis and ACL deficiency has satisfactory medium-term survivorship. BMI ≥30 could have higher risk of all-cause revision. Tibial tray overhang, non-progressive radiolucency or radiosclerosis do not seem to be associated with anteromedial knee pain or poorer medium term survivorship.

Proximal tibial bone loss in the first 2 years after unicondylar knee arthroplasty: Anatomical pattern, predictors and clinical correlation.

BACKGROUND: Tibial stress fracture, anteromedial bone pain, and early subsidence could occur after unicondylar knee arthroplasty (UKA). The change in metaphyseal tibial bone density (MTBD) in the coronal and sagittal planes after UKA might be a contributing factor, but this has rarely been investigated. The aim of this study was to assess the regional and temporal change in MTBD in the coronal and sagittal planes in the first 2 years after UKA. METHODS: Patients with fixed-bearing medial UKA were recruited. The change in MTBD in the first 24 months after UKA using digital radiological densitometry (DRD) was measured. Potential predictors and clinical correlations were analyzed. RESULTS: Eighty-four cases (female 60%) were selected for review. The follow up time was 63 (±17) months. Anterior and medial regions had the largest proportion of cases with MTBD reduction (90-97%, P < 0.05). Reduction was largest at anterior and medial regions (21-29%, P < 0.05) and smallest at posterior and lateral regions (5-15%, P < 0.05). Maximal reduction occurred at 12 months for the medial region and 24 months for the anterior region. MTBDs of both regions were not significantly influenced by any confounding factors. Significant correlation was found between medial MTBD and Function Score at 6 months. CONCLUSIONS: Bone loss in a zonal pattern occurs in the first 2 years after UKA with the largest loss in the anterior region below the tibial tray. It is not affected by body mass index, perioperative alignment, or angle of correction. This suggests a physiological response to trauma other than a mechanical response to the change in bone strain.

Forgotten Joint Score for early outcome assessment after total knee arthroplasty: Is it really useful?

BACKGROUND: Forgotten Joint Score (FJS) has become a popular tool for total knee arthroplasty (TKA), but almost all studies had assessment performed 1 year after surgery. There is a need for a sensitive tool for earlier outcome assessment. The aim of this study was to investigate the usefulness of FJS within the first year after TKA. METHODS: This was a cross-sectional study. Patients within the first year after primary TKA were recruited. FJS was translated into the local language with a cross-cultural adaptation and was validated by assessing the correlation with the Western Ontario and McMaster Universities Arthritis Index score (WOMAC). Ceiling and floor effects (highest or lowest 10% or 15%) of both scores were compared. Skewness of scores was assessed with a histogram. RESULTS: One hundred sixty-three subjects were recruited: 84 (51.5%) had evaluation at 3 months after the operation, 56 (34.4%) at 6 months, and 23 (14.1%) at 12 months. FJS had fewer patients at the highest 10% (10.7% vs. 16.1%, P = 0.046) or 15% (19.6% vs. 32.1%, P = 0.027) at 6 months and within the first year overall (6.7% vs. 13.5%, P <0.001; 14.1% vs. 22.7%, P <0.001). Also, it had more patients at the lowest 10% (16.7% vs. 0%, P <0.001) or 15% (21.4% vs. 0%, P <0.001) at 3 months, 6 months (10.7% vs. 0%, P <0.001), and overall (12.9% vs. 0%, P <0.001; 16.6% vs. 0%, P <0.001). The skewness was much less than WOMAC (0.09 vs. -0.56). CONCLUSIONS: FJS has a low ceiling effect but a high floor effect in the first year after TKA. Such characteristics make it less useful for the general assessment of early patient report outcome after operation.

Intraoperative femoral condyle fracture in primary total knee arthroplasty - a case-control study in Asian population.

PURPOSE: Intraoperative femoral condyle fracture is a significant but rarely reported complication during primary total knee arthroplasty (TKA). This is the first study to identify the incidence, risk factors, location and outcome of these fractures in an Asian population with modern posterior-stabilized (PS) TKA. MATERIALS AND METHODS: We reviewed 2682 consecutive primary TKAs performed between 2011 and 2017 in a single centre; 23 femoral condyle fractures were identified and analysed. RESULTS: Fractures were managed conservatively with screw fixation or revision arthroplasty. Mean follow up was 3.0 years (range 3 months to 5.9 years). All patients achieved bone union and good functional outcome. The mean Knee Society Knee score was 89.4 (range 71-100) and the function score was 80.2 (range 60-95) at a mean of 3.0 years post-operation. Bilateral surgery was found to be a significant risk factor for femoral condyle fracture, while there was a higher trend of fracture in female patients and Stryker articular surface mounted (ASM) navigation. CONCLUSIONS: Intraoperative fracture is not uncommon with modern PS TKA. Postulated risk factors for fracture were discussed. Early identification of risk factors and a rigorous surgical technique may reduce risk of fracture. A good functional result was expected after proper treatment.

Tibial tray thickness does not significantly increase medial tibial bone resorption: Using tibial bone density as an objective measurement method.

BACKGROUND: Recent studies have reported the occurrence of medial tibial bone resorption following total knee replacement. One study proposed that a thick tibial tray results in stress shielding and increases the risk of bone resorption, but its findings were based on subjective radiological assessment. This study aimed to verify this hypothesis and to objectively quantify medial tibial bone density by using serial measurements with digital radiological densitometry. METHODS: This was a retrospective cohort study involving 140 patients (70 thick tray vs. 70 thin tray) with cobalt-chromium implants with at least 24 months of follow-up. Standard radiographs were reviewed to look for incidence of medial tibial bone loss. Serial measurement of medial tibial bone density was also performed using the method of digital radiological densitometry. RESULTS: There was no significant difference in the incidence of medial tibial bone loss. Both groups showed a significant drop in medial tibial bone density after operation (P < 0.01). Medial tibial bone density of the thick-tray cohort was significantly higher than the thin-tray cohort at one year (93.3 vs. 83.1 Greyscale; P = 0.04), but not at two and three years. Clinical outcomes in terms of postoperative range of motion, Knee Society score and complication rates were similar. CONCLUSIONS: Medial tibial bone resorption is a common phenomenon. Implants with thicker tibial trays suffer less than those with thinner trays at one year, but the difference is transient and does not affect clinical outcome.

No difference in patient preference for medial pivot versus posterior-stabilized design in staged bilateral total knee arthroplasty: a prospective study.

PURPOSE: Medial pivot (MP) TKA has been shown to mimic normal knee kinematics with long-term survivorship comparable to most contemporary TKA. However, there are inadequate evidences to suggest its superiority in terms of patient preference and satisfaction. The aim of this study is to compare the MP with posterior-stabilized (PS) TKA in terms of patient preference and satisfaction. METHODS: 46 patients with staged bilateral TKA were recruited. TKA with MP or PS design was performed at interval of 6-12 months. Patient preference, patient satisfaction score (0-100), Forgotten Joint Score (FJS), range of motion (ROM), Pain Score, Knee Society Score (KSS), Knee Function Score (KFS) and WOMAC Score were compared at up to 12 months. RESULTS: The mean age was 70 and 69.6% were female. There was no difference in all preoperative parameters, operative time and length of stay between two knees. No difference was found in in range of motion and all outcome scores at 6 months and 12 months. Satisfaction score was similar for the two designs (82 vs 85, p = n.s.) at 1 year after the second TKA. Proportion of patients with preference on one design over another was not significantly different (28.9 vs 35.6%, p = n.s.). CONCLUSIONS: There is no evidence to support the superiority of MP TKA over PS TKA in terms of preference and satisfaction. The choice between MP TKA versus PS TKA maybe more a surgeon's preference than a patient's preference based on current evidence.

Blood Sparing Efficacy of Oral Tranexamic Acid in Primary Total Knee Arthroplasty: A Randomized Controlled Trial.

PURPOSE: Tranexamic acid (TXA) is effective in reducing blood loss in primary total knee replacement. Almost all studies used an intravenous form or a topical form. The aim of this study was to assess the blood sparing efficacy and the safety of oral TXA. MATERIALS AND METHODS: All patients with primary total knee replacement performed in our institute from January 2015 to October 2015 were eligible. Oral TXA group was given 1 g oral TXA 2 hours before induction of anesthesia and 6 hours and 12 hours postoperatively. The control group was not given TXA. RESULTS: There were 94 cases in the oral TXA group and 95 cases in the control group. There was no difference in the baseline characteristics. The oral TXA group had a significantly lower hemoglobin drop (1.7 g/dL vs. 2.5 g/dL), lower drain output (154 mL vs. 203 mL), lower hidden blood loss (244 mL vs. 423 mL) and lower total blood loss (398 mL vs. 626 mL). There was no difference in transfusion rate (1.1% vs. 3.2%) and thromboembolic complication. There was no infection or mortality in both groups. CONCLUSIONS: Oral TXA is effective in reducing blood loss in primary total knee replacement. It is a safe alternative to the intravenous or topical form.

Blood-Sparing Efficacy of Oral Tranexamic Acid in Primary Total Hip Arthroplasty.

BACKGROUND: Tranexamic acid (TXA) has been shown to be effective in reducing blood loss, hemoglobin drop, and blood transfusion in primary total hip arthroplasty. Most studies used intravenous form or topical form. This study was to assess the blood-sparing efficacy and safety of oral TXA in total hip arthroplasty. METHODS: Patients with primary total hip arthroplasty from 2012 to 2015 were recruited. Trial group with 1 gm of oral TXA 2 hours preoperatively, and 6 hours and 12 hours postoperatively was compared with the control group without drug. Outcome measures were intraoperative blood loss, drain output, observed total blood loss, actual total blood loss, hidden blood loss, hemoglobin drop, blood transfusion requirement, thromboembolic complications, cerebrovascular or cardiovascular complications, and mortality. RESULTS: After exclusion, 108 patients were included-54 in trial group and 54 in control group. There was no significant difference in the baseline characteristics. The trial group had significantly higher postoperative hemoglobin (10.3 vs 9.4 g/dL), lower hemoglobin drop (3.0 vs 4.1 g/dL), lower hidden blood loss (149 vs 354 mL), and lower actual total blood loss (847 vs 1096 mL). There was no significant difference in thromboembolic complications or mortality. There was also no periprosthetic infection or drug allergy. CONCLUSION: Oral TXA is effective in blood sparing in terms of reduction in hemoglobin drop, hidden blood loss, and actual total blood loss. It is safe and is an alternative to the intravenous or topical form.

Short duration and low suction pressure drain versus no drain following total knee replacement.

PURPOSE: To compare the short-term outcome in patients with or without a drain (short duration and low suction pressure) following total knee replacement (TKR). METHODS: A consecutive series of 106 women and 48 men (mean age, 69 years) underwent unilateral TKR. The first 77 patients used a low suction pressure (200 mm Hg) drain following TKR for 24 hours, and the next 77 patients used no drain. RESULTS: The 2 groups were comparable in terms of preoperative characteristics, the proportion of patients with pharmacological prophylaxis for deep vein thrombosis, the tourniquet time, and mode of anaesthesia. The mean drain output in the drain group was 221 ml. The time to achieve straight-leg-raising was earlier in the drain group (3.1 vs. 4.2 days, p<0.001). CONCLUSION: The use of a short duration, low suction pressure drain following TKR enabled an earlier return of quadriceps power, without increasing haemoglobin drop and transfusion rate.

Risk factors for periprosthetic joint infection in total knee arthroplasty.

PURPOSE: To evaluate the incidence and risk factors of periprosthetic joint infection (PJI) in patients undergoing total knee arthroplasty (TKA) in a high-volume hospital. METHODS: Records of 1133 primary TKAs were reviewed. Correlation between surgery volume and infection rate was determined. Risk factors for PJI were identified using case-control analysis of variables. TKAs performed between October 2012 and March 2013 without infection were used as controls. RESULTS: Of 1133 TKAs, 8 (0.71%) PJI occurred. The organisms involved were Staphylococcus aureus (n=4), coagulase-negative staphylococci (n=2), Pseudomonas aeruginosa (n=1), and methicillin-resistant S aureus (n=1). In the 6-month period chosen as the control period, one (0.52%) out of 192 TKAs developed PJI. Hospital annual volume did not correlate with infection rate (p=0.766). Significant risk factors included young age, comorbidities such as diabetes, anaemia, thyroid disease, heart disease, lung disease, and long operating time. Six of the 8 patients with PJIs had at least one risk factor. However, the number of patients with infection was too small to have sufficient power. CONCLUSION: Comorbidities are a risk factor for PJI. Perioperative optimisation of comorbidities and the use of antibiotic-loaded cement in patients with severe comorbidities should be considered.

Blood management protocol for total knee arthroplasty to reduce blood wastage and unnecessary transfusion.

PURPOSE: To compare outcomes of 2 cohorts of patients who underwent total knee arthroplasty (TKA) before and after the introduction of a blood management protocol. METHODS: Records of 97 and 96 consecutive patients who underwent unilateral TKA before and after introduction of the blood management protocol, respectively, were reviewed. Before introduction of the protocol, patients were cross-matched for blood before surgery. Transfusion after surgery was at the discretion of the surgeons or the on-call doctors. After introduction of the protocol, only patients with a preoperative haemoglobin level of <110 g/l underwent 'type and screening' of blood group. 2 units of blood were cross-matched preoperatively when multiple red-cell antibodies were identified or postoperatively when blood transfusion was required. Only patients with a postoperative haemoglobin level of <80 g/l or being symptomatic received blood transfusion until the haemoglobin level reached >100 g/l. Those with a postoperative haemoglobin level of 80 to 100 g/l were given iron sulphate 300 mg twice daily for a month. RESULTS: The 2 groups did not differ significantly in age, sex ratio, pre- and post-operative haemoglobin levels, and drain output. Comparing outcome before and after introduction of the protocol, the transfusion rate (10.3% vs. 3.1%, p=0.046), crossmatch rate (100% vs. 3.1%, p<0.001), and crossmatch to transfusion ratio (9.7:1 vs. 1:1, p<0.001) decreased. Among transfused patients, the decreased postoperative haemoglobin level indicated a lower transfusion trigger point (100 g/l vs. 75 g/l, p<0.006) No patient developed infection, cardiovascular or cerebrovascular complications within 30 days. CONCLUSION: The blood management protocol for TKA is effective in reducing unnecessary allogeneic blood transfusions and wastage of unused blood, without an increase in postoperative complications.

Effect of patellar thickness on early results of total knee replacement with patellar resurfacing.

PURPOSE: Patellar thickness is a concern in total knee replacement with patellar resurfacing because of the risk of patellar fracture or implant loosening. The aim of this study was to evaluate if patellar thickness is related to clinical outcome in the absence of patellar fracture or implant loosening. METHODS: Early results of 169 patients who underwent total knee replacement with patellar resurfacing were reviewed to assess the effect of patellar thickness on clinical outcome. The mean follow-up was 13 months. The range of motion, Knee Society Score, Function Score and WOMAC Score were assessed preoperatively, at day 0, 6 months and 1 year. Radiographs were assessed for patellar fracture or implant loosening. RESULTS: Thirty-one percent of all patients had preoperative thickness <21 mm. Seven percent had <12 mm residual thickness after patellar cut, all were female. Twenty-three percent had ≥1 mm increase of thickness after surgery. Radiographs did not show any patellar fracture or implant loosening. However, preoperative patellar thickness <21 mm had poorer gain in range of motion at 1 year. Preoperative range of motion had greater influence on postoperative range of motion than preoperative patellar thickness. Residual thickness <12 mm had lower gain in WOMAC score at 1 year and an increase in thickness ≥1 mm postoperatively was associated with lower gain in WOMAC score at 6 months. CONCLUSIONS: Early results of patellar resurfacing with preoperative thickness <21 mm or residual thickness <12 mm were found to be inferior even in the absence of patellar fracture or implant loosening. Conservative cutting resulting in 1 mm increase in thickness was also found to have inferior clinical results. LEVEL OF EVIDENCE: II.