Pre-operative sensor-based gait parameters predict functional outcome after total knee arthroplasty

BACKGROUND

Despite the general success of total knee arthroplasty (TKA) regarding patient-reported outcome measures, studies investigating gait function have shown diverse functional outcomes. Mobile sensor-based systems have recently been employed for accurate clinical gait assessments, as they allow a better integration of gait analysis into clinical routines as compared to laboratory based systems.

RESEARCH QUESTION

In this study, we sought to examine whether an accurate assessment of gait function of knee osteoarthritis patients with respect to surgery outcome evaluation after TKA using a mobile sensor-based gait analysis system is possible.

METHODS

A foot-worn sensor-based system was used to assess spatio-temporal gait parameters of 24 knee osteoarthritis patients one day before and one year after TKA, and in comparison to matched control participants. Patients were clustered into positive and negative responder groups using a heuristic approach regarding improvements in gait function. Machine learning was used to predict surgery outcome based on pre-operative gait parameters.

RESULTS

Gait function differed significantly between controls and patients. Patient-reported outcome measures improved significantly after surgery, but no significant global gait parameter difference was observed between pre- and post-operative status. However, the responder groups could be correctly predicted with an accuracy of up to 89% using pre-operative gait parameters. Patients exhibiting high pre-operative gait function were more likely to experience a functional decrease after surgery. Important gait parameters for the discrimination were stride time and stride length.

SIGNIFICANCE

The early identification of post-surgical functional outcomes of patients is of great importance to better inform patients pre-operatively regarding surgery success and to improve post-surgical management.

Oral thromboprophylaxis following total hip or knee replacement: review and multicentre experience with dabigatran etexilate

The risk of venous thromboembolism (VTE) in patients undergoing total knee or hip replacement surgery is high. As a result, thromboprophylaxis is highly recommended. While current thromboprophylactic agents, such as low molecular weight heparins (LMWH) and vitamin K antagonists, are safe and effective their use can be problematic. Therefore, there is a need for alternative anticoagulants that are as safe and effective as conventional agents, but are more convenient and easier to use. Dabigatran etexilate, a direct thrombin inhibitor, is one such anticoagulant. For VTE prevention following major orthopaedic surgery, dabigatran etexilate shows similar efficacy and safety to the LMWH enoxaparin, and is approved for use in more than 75 countries, including Europe and Canada. Here, we summarize and discuss the experiences of four German clinics that have recently introduced dabigatran etexilate into clinical practice. Overall, dabigatran etexilate was well received by patients, surgeons and nurses, and compared favourably with enoxaparin. Staff appreciated the oral, single-dose administration of dabigatran etexilate. Patient satisfaction was high, especially in those individuals who had previously used LMWHs. In this review, we also address a number of questions that were asked by patients or staff; this will be of relevance to orthopaedic surgeons and nurses. We conclude that, in these four German clinics, dabigatran etexilate offered an effective oral alternative to existing thromboprophylactic agents in patients undergoing major orthopaedic surgery.

Pre-operative pressure pain thresholds do not meaningfully explain satisfaction or improvement in pain after knee replacement: a cohort study

OBJECTIVES

Pain sensitization could be a risk factor for poor outcomes after knee replacement surgery (KR) for knee osteoarthritis (KOA). We aimed to evaluate the association between pre-operative central and peripheral pain sensitization measured using a digital pressure algometer and KR outcomes.

METHODS

Consecutive patients with severe KOA listed for KR were recruited. Sociodemographic and symptoms data were collected prior to surgery. Pre-operative pressure pain thresholds (PPTs) were measured using a digital pressure algometer at the index knee and forearm. Patient satisfaction at 6 and 12 months after KR was assessed using a 4-point Likert scale, and dichotomized to satisfied and dissatisfied to KR. Western Ontario and McMaster Universities Index (WOMAC) Pain and function was assessed. The associations between pre-operative PPTs with KR outcomes at 6 and 12 months were evaluated.

RESULTS

Of the 243 patients recruited, response rate at 6 and 12 months were 95.5% and 96.7%. The dissatisfaction rates were 8.2% and 5.1% at 6 and 12 months. There was no statistically significant association between pre-operative index knee or forearm PPTs and patient satisfaction. PPTs measured at the knee, but not the forearm, were weakly associated with change in the WOMAC pain score at 12 months, after adjustment for confounding factors.

CONCLUSION

Pre-operative central sensitization, measured by handheld digital algometry, was not statistically significantly associated with satisfaction or change in pain after KR. Pre-operative peripheral sensitization was associated with change in pain symptoms after KR; however, this association was weak and unlikely to be a meaningful predictor of KR outcome in clinical practice.

Patient preferences for total knee replacement surgery: Relationship to clinical outcomes and stability of patient preferences over 2 years

OBJECTIVE

Evaluate the relationship between patient preferences for total knee replacement (TKR) with receipt of TKR, and assess participant characteristics that may influence change in willingness to undergo TKR.

METHODS

Structured interviews of knee osteoarthritis (OA) patients were conducted. Logistic regression models were conducted to assess the association between baseline willingness and eventual receipt of TKR, adjusted for sociodemographic and clinical variables. Mixed models for repeated measures were used to estimate the effects of sex, race, social support, Δ WOMAC, and orthopedic consult on change in willingness.

RESULTS

A total of 589 participants were willing, and 215 participants were unwilling to undergo TKR. Willing participants, compared to others, were more often White (69.4% vs. 48.4%), with more than a high school education (60.8% vs. 47.0%) and employed (39.1% vs. 26.5%). At follow-up, the odds of having TKR were twice as high among those who were willing to have the procedure at baseline, but this was no longer significant when adjusted for demographic variables (adjusted OR = 1.82, 95% CI: 0.89-3.69). Willingness to undergo TKR declined over 2 years. Among those who were willing to undergo TKR at baseline but did not obtain one, only 66.5% were still willing at the 2-year follow-up. This decline was less among those who had a greater increase (>median) in WOMAC disability (adjusted Δ = -0.34, 95% CI: -0.47 to -0.20) than those who had minimal change in their WOMAC disability (p = 0.08). The decline in willingness was also less among those who had seen an orthopedic surgeon (adjusted Δ = -0.32, 95% CI: -0.46 to -0.17) than those who did not (p = 0.05).

CONCLUSIONS

Preference for TKR was consistent with TKR surgery utilization, but not after controlling for patient demographic characteristics. Willingness to undergo TKR declined over time, but this decrease was mitigated by worsening OA-related disability and by consultation with an orthopedic surgeon.

Safety and efficacy of switching from low molecular weight heparin to dabigatran in patients undergoing elective total hip or knee replacement surgery

Background

The aim of this study was to assess the safety and efficacy of switching therapy from low molecular weight heparin (LMWH; enoxaparin) to dabigatran for prevention of venous thromboembolic events (VTE) in patients undergoing elective total hip or knee replacement surgery (THR/TKR).

Methods

This was a prospective, multicenter, open-label, single-arm, observational, study in patients undergoing THR or TKR who were to receive enoxaparin 40 mg for thromboprophylaxis. Enoxaparin was initiated before or after surgery according to local practice, and was switched to dabigatran 220 mg once daily at a time point chosen by the investigator. The coprimary endpoints were major bleeding events, and the composite of symptomatic VTE and all-cause mortality, from last use of enoxaparin to 24 h after last intake of dabigatran.

Results

Altogether, 168 (81 THR, 87 TKR) patients were enrolled, of whom 161 received both enoxaparin and dabigatran, 2 received dabigatran only and 5 received enoxaparin only. The median time of the first dabigatran tablet was 24.0 h after the last LMWH dosage and the median number of days on dabigatran treatment was 36 days. No symptomatic VTE or death occurred during the study. One major bleeding event was seen at the surgical site and required treatment cessation. Three minor bleeding events were observed.

Conclusions

In the normal clinical setting, switching from LMWH to dabigatran in patients who had undergone THR and TKR was safe and effective in preventing VTE. The reported adverse events and serious adverse events were consistent with the known safety profile for dabigatran. Switching from a subcutaneous to an oral anticoagulant may offer greater convenience in the outpatient setting after discharge.

Trial registration

ClinicalTrials.gov identifier NCT01153698.

Numerical optimization of alignment reproducibility for customizable surgical guides

PURPOSE

Computer-assisted orthopedic surgery aims at minimizing invasiveness, postoperative pain, and morbidity with computer-assisted preoperative planning and intra-operative guidance techniques, of which camera-based navigation and patient-specific templates (PST) are the most common. PSTs are one-time templates that guide the surgeon initially in cutting slits or drilling holes. This method can be extended to reusable and customizable surgical guides (CSG), which can be adapted to the patients' bone. Determining the right set of CSG input parameters by hand is a challenging task, given the vast amount of input parameter combinations and the complex physical interaction between the PST/CSG and the bone.

METHODS

This paper introduces a novel algorithm to solve the problem of choosing the right set of input parameters. Our approach predicts how well a CSG instance is able to reproduce the planned alignment based on a physical simulation and uses a genetic optimization algorithm to determine optimal configurations. We validate our technique with a prototype of a pin-based CSG and nine rapid prototyped distal femora.

RESULTS

The proposed optimization technique has been compared to manual optimization by experts, as well as participants with domain experience. Using the optimization technique, the alignment errors remained within practical boundaries of 1.2 mm translation and [Formula: see text] rotation error. In all cases, the proposed method outperformed manual optimization.

CONCLUSIONS

Manually optimizing CSG parameters turns out to be a counterintuitive task. Even after training, subjects with and without anatomical background fail in choosing appropriate CSG configurations. Our optimization algorithm ensures that the CSG is configured correctly, and we could demonstrate that the intended alignment of the CSG is accurately reproduced on all tested bone geometries.

Physician induced demand for knee replacement surgery in Iran

BACKGROUND

The structure of the Iranian health system has raised this hypothesis that a part of the Knee Replacement Surgery (KRS) services are provided due to Physician-Induced Demand (PID).

METHODS

This paper used an unbalanced individual panel data covering the steady-state 15,729 KRSs performed by 995 surgeons provided by the Armed Forces Insurance Organization at the provincial level over the 60 months (2014-2018). We use a generalized method of moment's system (GMM-SYS) to obtain consistent and asymptotically efficient estimates, which provide a vital instrument for our dynamic panel data.

RESULTS

The outcomes show that with unequal increasing orthopedic surgeons to population ratio, both the number and size of KRS services were increased significantly at a 1 % level. Given that the positive elasticity obtained for the service size was significantly larger than the number of services, the findings give strong support for the existence of PID in the Iran system for KRS care. Also, the raw and population-adjusted number of KRS, cost, and the surgery per active physician increased significantly at the monthly province level.

CONCLUSIONS

This is the first time that the existence of PID in the Iranian health system is investigated using approved econometric models. The findings indicate that the health system structure has been provided the conditions for aggressive, costly, and high-risk services such as KRS to be exposed to PID.

Safety and outcomes of hip and knee replacement surgery in liver transplant recipients

BACKGROUND

Liver transplant (LT) is becoming increasingly common with improved life expectancy. Joint replacement is usually a safe procedure; however, its safety in LT recipients remains understudied.

AIM

To evaluate the mortality, outcome, and 90-d readmission rate in LT patients undergoing hip and knee replacement surgery.

METHODS

Patients with history of LT who underwent hip and knee replacement surgery between 2016 and 2019 were identified using the National Readmission Database.

RESULTS

A total of 5046119 hip and knee replacement surgeries were identified. 3219 patients had prior LT. Mean age of patients with no history of LT was 67.51 [95% confidence interval (CI): 67.44-67.58], while it was 64.05 (95%CI: 63.55-64.54) in patients with LT. Patients with history of LT were more likely to have prolonged length of hospital stay (17.1% vs 8.4%, P < 0.001). The mortality rate for patients with no history of LT was 0.22%, while it was 0.24% for patients with LT (P = 0.792). Patients with history of LT were more likely to have re-admissions within 90 d of initial hospitalization: 11.4% as compared to 6.2% in patients without history of LT (P < 0.001). The mortality rate between both groups during readmission was not statistically different (1.9% vs 2%, P = 0.871) respectively.

CONCLUSION

Hip and knee replacements in patients with history of LT are not associated with increased mortality; increased re-admissions were more frequent in this cohort of patients. Chronic kidney disease and congestive heart failure appear to predict higher risk of readmission.

Lateral epicondyle to the joint line distance is a precise landmark for determination of an accurate knee joint line: an observational retrospective study

PURPOSE

To assess a quantitative and reproducible association between the position of the knee joint line and recognizable anatomical landmarks around it in order to help in restoring joint line in arthroplasty cases.

METHODS

Magnetic resonance imaging (MRI) of 130 normal knees were investigated. Anatomical measurements of the knee joint distances on the obtained planes were performed manually by distance measurements using a ruler tool, followed by 6 anatomical bony landmarks determination about the knee to identify the joint line which included the joint line, medial epicondyle, lateral epicondyle, medial flare, lateral flare, and proximal tibiofibular joint. The entire process was examined twice by two independent fellowship trained musculoskeletal radiologists, with a 2-week interval between the first and second sets of readings.

RESULTS

The lateral epicondyle to the joint line of the knee (LEJL) could be a reliable landmark for accurate distance measurements for the knee joint line level, with an absolute distance of 24.4 ± 2.8 mm. The analysis showed that the femorotibial ratio between the LEJL and proximal tibiofibular joint (PTFJ) was 1.0 (LEJL/PTFJJL = 1.0 ± 0.1), confirming the location of the knee joint at the midpoint between the lateral epicondyle and PTFJ, revealing two identifiable landmarks.

CONCLUSIONS

LEJL is the most precise landmark for determination of an accurate knee joint line because the knee is located at the midline between the lateral epicondyle and PTFJ. These reproducible quantitative relationships can be widely employed in various imaging modalities to help restore the knee JL in arthroplasty surgeries.

Subtrochanteric fracture of the femur following knee replacement surgery: A case series and review of the literature

INTRODUCTION AND IMPORTANCE

Knee arthroplasties as an effective intervention is primarily performed in patients with primary osteoarthritis and rheumatoid arthritis. Risk of hip fracture may be either decreased or increased in patients with Knee arthroplasties. There is conflicting evidence in this regard. Over the years, some studies have reported the occurrence of hip fractures following this operation as a rare but severe complication. The aim of the present case series was to report diagnosis and treatment of the mentioned five cases.

CASE PRESENTATION

During a period of two years, five patients with a diagnosis of a subtrochanteric fracture and history of total knee arthroplasty who referred to hospital were selected to include in the present case series. CLINICAL DISCUSSION: the presence of RA and treatment with glucocorticoids, a reduction of BMD following knee replacement surgery, and ultimately, an increase in physical activity and movement after the arthroplasty due to the improvement of preoperational pain, may all contribute in a complex manner to the observed outcome of increased fracture risk in the hip following TKA.

CONCLUSION

In summary, special care including using medications to improve BMD should be taken to minimize the risk of such an event.

A radiographic artificial intelligence tool to identify candidates suitable for partial knee arthroplasty

INTRODUCTION

Knee osteoarthritis is a prevalent condition frequently necessitating knee replacement surgery, with demand projected to rise substantially. Partial knee arthroplasty (PKA) offers advantages over total knee arthroplasty (TKA), yet its utilisation remains low despite guidance recommending consideration alongside TKA in shared decision making. Radiographic decision aids exist but are underutilised due to clinician time constraints.

MATERIALS AND METHODS

This research develops a novel radiographic artificial intelligence (AI) tool using a dataset of knee radiographs and a panel of expert orthopaedic surgeons' assessments. Six AI models were trained to identify PKA candidacy.

RESULTS

1241 labelled four-view radiograph series were included. Models achieved statistically significant accuracies above random assignment, with EfficientNet-ES demonstrating the highest performance (AUC 95%, F1 score 83% and accuracy 80%).

CONCLUSIONS

The AI decision tool shows promise in identifying PKA candidates, potentially addressing underutilisation of this procedure. Its integration into clinical practice could enhance shared decision making and improve patient outcomes. Further validation and implementation studies are warranted to assess real-world utility and impact.

Comparison of bilateral cementless total knee arthroplasty results between patients in different BMI groups

INTRODUCTION

The aim of this study was to compare the results of cementless bilateral total knee arthroplasty (TKA) between individuals in different obesity groups.

MATERIALS AND METHODS

This was a retrospective cohort study. Patients with a body mass index (BMI) greater than 25 who underwent bilateral TKA for gonarthrosis between 2014 and 2020 and completed a minimum follow-up of 24 months were included. Age, sex, height, weight, BMI, operation time, length of stay, patient satisfaction, knee scores and complications were compared. Patients with missing data, who were followed for less than 24 months or had postoperative fractures around the knee were excluded.

RESULTS

There was a significant difference between the groups in terms of operation time (Class III > overweight > Class II > Class I p < 0.001). There was a significant difference in complications between the groups (Class III > Class I > Class II > overweight p = 0.010). According to our pairwise comparison, complications were more common in the class III group than in the overweight group. Knee score (KS) and function score (FS) increased significantly after surgery in all groups (p < 0.001), with no difference in FS (p = 0.448). Knee score changes were greater in the overweight and class I groups (p < 0.001). There was a significant interaction between both KS and FS and person satisfaction (p < 0.001).

CONCLUSION

Cementless TKA improved KS and FS in all obesity groups, yielded high patient satisfaction. Although the incidence of complications was higher in the morbidly obese patients than in the overweight patients, the difference was not significant. Patients with morbid obesity should be informed about related risks before planning cementless TKA.