The maximal gait speed is a simple and useful prognostic indicator for functional recovery after total hip arthroplasty

Effect of Early Postoperative Gait Parameters After Total Hip Arthroplasty on Forgotten Joint Score-12 at 2-Year Follow-Up

Purpose: This study aimed to elucidate the relationship between early postoperative gait parameters after total hip arthroplasty (THA) and the Forgotten Joint Score-12 (FJS-12) score at the 2-year follow-up after surgery. In addition, the cutoff gait parameter values for predicting discomfort using specific FJS-12 subitems were evaluated. Methods: Among 313 patients who underwent THA between April and December 2019, 44 (14.0%) who responded to the FJS-12 questionnaire at 2 years postoperatively were included in this study. Gait parameters, including walking speed, stride length, and their coefficients of variation (CVs), were measured at 13.8 ± 3.6 (mean ± standard deviation) days postoperatively. The FJS-12 was used to evaluate patients at 2 years after surgery. The correlation between the FJS-12 score and gait parameters was analyzed using Spearman's rank correlation coefficient. To determine the significant predictors of the FJS-12 score, multiple regression analysis was performed after adjusting for age as a covariate. Furthermore, receiver operating characteristic curves were used to determine the cutoff gait parameter values for predicting discomfort using specific FJS-12 subitems. Results: The FJS-12 score was significantly positively correlated with walking speed (rs = 0.38, p < 0.05) and stride length (rs = 0.51, p < 0.01). Meanwhile, the FJS-12 score was significantly negatively correlated with the CVs of walking speed (rs = -0.34, p < 0.05) and stride length (rs = -0.35, p < 0.05). Based on multiple regression analysis, stride length was a significant predictor of discomfort assessed using the FJS-12 score (β = 0.48, p < 0.01). According to the receiver operating characteristic curves, the cutoff stride length values for predicting discomfort using the FJS-12 subitems 9, 10, 11, and 12 showed moderate accuracy (area under the curve > 0.7). Conclusions: Improved walking ability of patients who underwent THA through early rehabilitation is linked to joint discomfort and patient satisfaction in daily life 2 years postoperatively.

Preoperative hip abductor strength predicts discharge destination after total hip arthroplasty

PURPOSE

This study aimed to clarify the association between preoperative physical function and discharge destination after total hip arthroplasty (THA).

METHODS

This retrospective study included patients who underwent primary unilateral THA for hip osteoarthritis. Preoperative physical function was assessed via maximal isometric muscle strength (hip abduction and knee extension) and comfortable walking speed. The patients were divided into two groups according to the discharge destination (home or transfer to other facilities). Multivariate logistic regression analysis was used to identify preoperative physical function associated with discharge destination.

RESULTS

Of the 174 patients, 120 were discharged directly to home, and 54 were transferred to other facilities. Those transferred to other facilities were significantly older, more likely to live alone, and had a longer operation time. In addition, they demonstrated lower hip abductor strength on both sides and lower knee extensor strength on the operative side. Multivariate logistic regression analysis revealed that hip abductor strength on both sides, not knee extensor strength, was independently associated with the discharge destination. The largest area under the receiver operating characteristic curve was 0.668 for the hip abductor strength of the contralateral side. The optimal cutoff point was revealed to be 0.035 kgf·m/kg and 0.031 kgf·m/kg for the operative and contralateral sides, respectively.

CONCLUSIONS

Preoperative hip abductor strength, particularly on the contralateral side with a cutoff value of 0.031 kgf·m/kg, could be a predictor of discharge destination after unilateral THA. Our findings would be useful in planning rehabilitation programs.

Machine learning model identifies patient gait speed throughout the episode of care, generating notifications for clinician evaluation

INTRODUCTION

The advent of digital and mobile health innovations, especially use of wearables for passive data collection, allows remote monitoring and creates an abundance of data. For this information to be interpretable, machine learning (ML) processes are necessary.

RESEARCH QUESTION

Can a machine learning model successfully identify patients expected to have low gait speed in the early recovery period following joint replacement surgery?

METHODS

A commercial database from a smartphone-based care management platform passively collecting mobility data pre- and post-lower limb arthroplasty was used. We sought to create a ML model to predict gait speed recovery curves and identify patients at risk of poor gait speed outcome, a measure associated with range of motion and patient-reported outcomes. Model performance including sensitivity, specificity, precision, and accuracy were determined. Receiver operator curve (ROC) analysis was used to compare true and false positive rates. To benchmark our model, we compared threshold-based notifications based on the patient's current gait speed.

RESULTS

The performance of the predictive model was significantly improved compared to baseline of threshold-based exceptions using current gait speed. The ML model currently provides 53 % precision, 88 % accuracy, 36 % sensitivity, and 95 % specificity on the held-out test set. The ROC analysis suggests good clinical performance (AUC=0.81).

SIGNIFICANCE

Utilization of ML to predict gait recovery following total joint replacement is feasible and provides results with excellent specificity. This model will allow inclusion of additional data for retraining as patient populations evolve. Clinician feedback regarding notifications, including resulting actions and outcomes, can be used to further inform the model and improve clinical utility.

Preoperative Sarcopenia Severity and Clinical Outcomes after Total Hip Arthroplasty

The outcome of total hip arthroplasty (THA) in patients with end-stage arthritis of the hip is associated with preoperative physical status. This study was performed to examine the relationship between the preoperative severity of sarcopenia and clinical outcomes after THA. This retrospective cohort study was performed among 306 consecutive patients (mean age: 63.7 ± 12.9 years, 222 women) undergoing THA at a university hospital. The severity of sarcopenia was determined based on the skeletal muscle mass index (SMI), handgrip strength, and gait speed according to the criteria of the Asian Working Group for Sarcopenia 2019. The severe sarcopenia prevalence rate was 10.6%. Severe sarcopenia was significantly associated with the risk of delayed functional recovery (adjusted odds ratio, 2.82; 95% confidence interval, 1.03-7.72; p = 0.043) compared with the non-sarcopenia group after adjusting for pre-existing risk factors, including preoperative hip function and physical activity. The addition of SMI, handgrip strength, and gait speed to the model for risk of functional recovery delay significantly increased the area under the receiver operating characteristic curve (p = 0.038). Severe sarcopenia was significantly associated with poorer hip function and patient-reported outcomes at 6 months after surgery compared with the non-sarcopenia group. Severe sarcopenia was adversely associated with postoperative clinical outcomes in patients undergoing THA.

Motion acquisition of gait characteristics one week after total hip arthroplasty: a factor analysis

INTRODUCTION

Clinical gait analysis can be used to evaluate the recovery process of patients undergoing total hip arthroplasty (THA). The postoperative walking patterns of these patients can be significantly influenced by the choice of surgical approach, as each procedure alters distinct anatomical structures. The aim of this study is twofold. The first objective is to develop a gait model to describe the change in ambulation one week after THA. The secondary goal is to describe the differences associated with the surgical approach.

MATERIALS AND METHODS

Thirty-six patients undergoing THA with lateral (n = 9), anterior (n = 15), and posterior (n = 12) approaches were included in the study. Walking before and 7 days after surgery was recorded using a markerless motion capture system. Exploratory Factor Analysis (EFA), a data reduction technique, condensed 21 spatiotemporal gait parameters to a smaller set of dominant variables. The EFA-derived gait domains were utilized to study post-surgical gait variations and to compare the post-surgical gait among the three groups.

RESULTS

Four distinct gait domains were identified. The most pronounced variation one week after surgery is in the Rhythm (gait cycle time: + 32.9 % ), followed by Postural control (step width: + 27.0 % ), Phases (stance time: + 11.0 % ), and Pace (stride length: -  9.3 % ). In postsurgical walking, Phases is statistically significantly different in patients operated with the posterior approach compared to lateral (p-value = 0.017) and anterior (p-value = 0.002) approaches. Furthermore, stance time in the posterior approach group is significantly lower than in healthy individuals (p-value < 0.001).

CONCLUSIONS

This study identified a four-component gait model specific to THA patients. The results showed that patients after THA have longer stride time but shorter stride length, wider base of support, and longer stance time, although the posterior group had a statistically significant shorter stance time than the others. The findings of this research have the potential to simplify the reporting of gait outcomes, reduce redundancy, and inform targeted interventions in regards to specific gait domains.

A Retrospective Study on the Feasibility of Using Low-burden Patient-reported Pain Scores to Track Recovery and Outcomes After Total Joint Replacement

Background

Patients undergo total joint arthroplasty to improve function and resolve pain. Patient-reported outcome measures (PROMs) are often sought to determine the success of total joint arthroplasty but are time-consuming and patient response rates are often low. This study sought to determine whether pain numeric rating scores (NRSs) were associated with PROMs and objective mobility outcomes.

Methods

This is a retrospective review of data in patients who utilized a smartphone-based care management application prior to and following total joint arthroplasty. NRS, Hip Disability and Osteoarthritis Outcome Score, Joint Replacement and Knee Injury and Osteoarthritis Outcome Score, Joint Replacement, and objective mobility data (step counts, gait speed, and gait asymmetry) were collected preoperatively and at 30 and 90 days postoperatively. Quantile regression was performed to evaluate the correlations between NRS and PROMs.

Results

Total knee arthroplasty patients reported higher NRS than total hip arthroplasty patients postoperatively. NRS was significantly correlated with gait speed preoperatively and at 30 and 90 days postoperatively on quantile regression. Gait asymmetry was significantly associated with NRS at 30 days postoperatively. Regression results suggested significant correlations between NRS and PROMs scores; Hip Disability and Osteoarthritis Outcome Score, Joint Replacement, -0.46 (95% confidence interval: -0.48 to -0.44, P < .001) and Knee Injury and Osteoarthritis Outcome Score, Joint Replacement, -0.38 (95% confidence interval: -0.40 to -0.36, P < .001).

Conclusions

NRS is correlated with both objective and subjective measures of function in patients undergoing arthroplasty. Simple pain ratings may be a valid measurement to help predict functional outcomes when collection of traditional PROMs is not feasible.

Incorporating Functional Strength Integration Techniques During Total Hip Arthroplasty Rehabilitation: A Randomized Controlled Trial

OBJECTIVE

Total hip arthroplasty (THA) is a common orthopedic procedure that alleviates pain for millions of individuals. Yet, persistent physical function deficits, perhaps associated with movement compensations, are observed after THA. These deficits negatively affect quality of life and health for many individuals. Functional strength integration (FSI) techniques combine muscle strength training with specific movement retraining to improve physical function. This study aimed to determine if FSI would improve functional performance through remediation of movement compensations for individuals after THA.

METHODS

A double-blind randomized controlled trial was conducted. Ninety-five participants were randomized to either the FSI or control (CON) group for an 8-week intervention. The FSI protocol included exercise to improve muscular control and stability around the hip to minimize movement compensation during daily activity. The CON protocol included low-load resistance exercise, range-of-motion activities, and patient education. Functional performance, muscle strength, and self-reported outcomes were measured preoperatively, midway and after intervention, and 6 months after THA. Change from preoperative assessment to each time point was measured, and between-group differences were assessed.

RESULTS

There were minimal differences in outcomes between groups at the first postoperative assessment. There were no statistically significant between-group differences in the later assessments, including the primary endpoint. Both groups improved functional outcomes throughout the study period.

CONCLUSION

The FSI intervention did not result in greater improvements in function after THA compared to the CON intervention. Future work should further investigate additional biomechanical outcomes, timing of the FSI protocol, effective dosing, and patient characteristics predictive of success with FSI.

IMPACT

Recovery after THA is complex, and individuals after THA are affected by persistent movement deficits that affect morbidity and quality of life. The present study suggests that either approach to THA rehabilitation could improve outcomes for patients, and that structured rehabilitation programs may benefit individuals after THA.

Strategies to optimise machine learning classification performance when using biomechanical features

Building prediction models using biomechanical features is challenging because such models may require large sample sizes. However, collecting biomechanical data on large sample sizes is logistically very challenging. This study aims to investigate if modern machine learning algorithms can help overcome the issue of limited sample sizes on developing prediction models. This was a secondary data analysis two biomechanical datasets - a walking dataset on 2295 participants, and a countermovement jump dataset on 31 participants. The input features were the three-dimensional ground reaction forces (GRFs) of the lower limbs. The outcome was the orthopaedic disease category (healthy, calcaneus, ankle, knee, hip) in the walking dataset, and healthy vs people with patellofemoral pain syndrome in the jump dataset. Different algorithms were compared: multinomial/LASSO regression, XGBoost, various deep learning time-series algorithms with augmented data, and with transfer learning. For the outcome of weighted multiclass area under the receiver operating curve (AUC) in the walking dataset, the three models with the best performance were InceptionTime with x12 augmented data (0.810), XGBoost (0.804), and multinomial logistic regression (0.800). For the jump dataset, the top three models with the highest AUC were the LASSO (1.00), InceptionTime with x8 augmentation (0.750), and transfer learning (0.653). Machine-learning based strategies for managing the challenging issue of limited sample size for biomechanical ML-based problems, could benefit the development of alternative prediction models in healthcare, especially when time-series data are involved.

Association of affected and non-affected side ability with postoperative outcomes in patients undergoing total hip arthroplasty

BACKGROUND

Although several reports have examined the association between preoperative function and postoperative outcomes in patients undergoing total hip arthroplasty (THA), it is unclear whether the ability of the affected or non-affected side particularly impacts on outcomes. We aimed to investigate the association between affected and non-affected side ability and walking independence.

METHODS

We prospectively enrolled 721 consecutive patients who underwent THA. Preoperatively, quadriceps isometric strength (QIS) and one-leg standing time (OLST) were measured. The endpoints were walking independence within 3, 5, 7, 10, and 14 days postoperatively. The associations between preoperative abilities and outcomes were examined using multivariate Cox hazard model, and the area under the curves (AUCs) for outcomes were compared.

RESULTS

We analysed 540 patients after excluding patients who met the exclusion criteria. Both affected and non-affected QIS predicted walking independence within 3 (p = 0.006 and 0.001, respectively), 5, 7, 10, and 14 (both p < 0.001) days postoperatively. For OLST, only the affected side did not predict walking independence within 3 days postoperatively (p = 0.154 and 0.012, respectively), and both sides did at days 5 (p = 0.019 and <0.001, respectively), 7, 10, and 14 (both p < 0.001). The AUCs of the non-affected side ability for walking independence were significantly greater than those of the affected side on postoperative days 3 (0.66 vs. 0.73; p = 0.021) and 5 (0.67 vs. 0.71; p = 0.040), with no significant difference after day 7.

CONCLUSIONS

Both sides abilities were associated with walking independence after THA, but non-affected side was found to be particularly crucial for early walking independence.

Hip resurfacing arthroplasty in women: A novel ceramic device enables near normal gait function

BACKGROUND

Gait function improves after Total Hip Arthroplasty (THA) but is not restored to normal levels. Metal-on-metal Resurfacing Arthroplasty (MoM-HRA) is an alternative to THA and has shown to restore normal levels gait function and physical activity but has been restricted to men owing to problems of metal-ion release. Ceramic HRA (cHRA) removes the cobalt-chrome bearing surfaces, thereby eliminating these specific metal-ion concerns and aiming to be safe for females.

RESEARCH QUESTION

Is there a difference in gait function of female cHRA patients compared to female THA using subjective and objective measures?

METHODS

Fifteen unilateral cHRA and 15 unilateral THA, age and BMI matched, completed patient reported outcome measures (PROMs) (Oxford Hip Score, EQ5d and MET score) and underwent gait analysis using an instrumented treadmill pre- (2-10 weeks) and post-operatively (52-74 weeks). Maximum walking speed (MWS), Vertical GRF of the stance phase, GRF symmetry index (SI) and spatiotemporal gait measures were recorded. Patients were compared to age, gender and BMI healthy controls (CON).

RESULTS

There were no differences in PROMs or gait function between groups pre-operatively. Post- operatively, cHRA had a higher MET score (11.2 vs 7.1, p = 0.02) and a higher MWS (6.2 vs 6.8 km/hr, p = 0.003) compared to THA. cHRA had a similar GRF profile to CON, whereas THA had a reduced push-off force at 70-77 % of the stance phase compared to CON. At faster walking speeds of 6 km/hr walking speed, THA displayed an asymmetric GRF profile (SI<4.4 %) whereas the cHRA patients continued to display a symmetrical gait profile. cHRA was able to increase step length from pre-op levels (63 vs 66 cm, p = 0.02) and produced a larger step length compared to THA (73 vs 79 cm, p = 0.02).

SIGNIFICANCE

Female cHRA returned to levels of gait function and activity similar to healthy controls unlike female THA.

The effect of a digital-assisted group rehabilitation on clinical and functional outcomes after total hip and knee arthroplasty-a prospective randomized controlled pilot study

BACKGROUND

The rising number of total hip and knee arthroplasties and the decreasing availability of physiotherapists require clinically and economically effective rehabilitation approaches. Therefore, the present pilot study investigated the effect of a novel digital-assisted individualized group rehabilitation program on clinical and functional outcomes after total hip and knee arthroplasty.

METHODS

In this randomized controlled pilot study, 26 patients undergoing total knee or hip replacement were randomly assigned to either the intervention group (IG, novel digital-assisted group therapy) or the control group (CG, standard postoperative physiotherapy currently carried out in Germany). The IG received the novel digital-assisted group therapy twice per week for a six-months period, while the CG received individual outpatient therapy depending on the prescription of the supervising physician. The number of therapy sessions was recorded. Moreover, subjective outcomes (EuroQol-5Dimensions (EQ-5D) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)), functional outcome (30 s sit to stand test and timed up and go test (TUG)), as well as gait parameters were quantified preoperatively as well as at three and six months after surgery. Data were analyzed using an analysis of covariance with baseline-adjustment.

RESULTS

No patient-reported falls, pain, and hospital readmissions were recorded. On average, the IG received more therapy sessions. The clinical and functional outcomes were mainly not significantly different between groups at three- and six-months follow-up, but medium to large effect sizes for the differences in quality of life (EQ-5D) as well as pain, stiffness, and physical function (WOMAC), and TUG performance were observed in favor of the IG. However, the IG showed a higher variability of gait velocity after total joint replacement.

CONCLUSION

The digital-assisted rehabilitation had positive effects on quality of life, pain, stiffness, physical function, and TUG performance. Nevertheless, the therapy concept may be improved by adding exercises focusing on gait performance to reduce gait variability. The results indicate that the digital-assisted therapy concept is effective and safe. Therefore, a consecutive full-scaled randomized controlled clinical trial is recommended.

TRIAL REGISTRATION

This study was retrospectively registered on 14/02/2022 in the German Clinical Trial Register (DRKS00027960).

Clinical Effect of Application of Interventional Treatment Models for Improvement of Quality of Postoperative Recovery in Elderly Patients with Total Hip Arthroplasty

OBJECTIVE

To investigate the application value of the interventional treatment model for improving the recovery of elderly patients after total hip arthroplasty (THA).

METHODS

A total of 50 patients who received THA were randomly divided into the control group (25 cases) undergoing traditional treatment and the experimental group (25 cases) undergoing intervention of cognition, emotion, environment, education, nutrition, and sleep. The mini-mental state examination (MMSE) score, the incidence and duration of postoperative cognitive dysfunction (POCD), the out-of-bed activity time, hospital stays, and the satisfaction degree of patients were compared between the two groups.

RESULTS

There was no statistically significant difference in basic information between the two groups. On days 7 and 14 after surgery, the MMSE score of the control group was significantly lower than that of the experimental group (P <0.05). The incidence of POCD in the experimental group was lower and its duration was shorter than in the control group but without statistical significance. Besides, the significantly decreased out-of-bed activity time, the reduced length of hospital stay, and the higher satisfaction degree were observed in the experimental group (P <0.05).

CONCLUSION

Interventional treatment model could significantly increase the MMSE score, accelerate the recovery of elderly patients after THA, and increase their satisfaction degree.

Sensory substitution for orthopaedic gait rehabilitation: A systematic review and meta-analysis for clinical practice guideline development

Introduction

Sensory Substitution is a biofeedback intervention whereby at least sensory system is utilised to supplement environmental information which is traditionally gathered by another sense.

Objective

To present an evidence-based overview of the feasibility and effectiveness of wearable Sensory Substitution devices on gait outcomes in orthopaedic patient populations.

Methods

This Systematic Review and Meta-Analysis was reported according to the PRISMA 2020 statement. PubMed, the Cochrane Library, Web of science and PEDro were searched for relevant published literature. Inclusion criteria limited the search strictly to patients diagnosed with an orthopaedic condition and who were randomly grouped to a Sensory Substitution intervention or conventional therapy/training or an equivalent placebo intervention.

Results

Nine Randomised Controlled Trials and three Crossover Trials investigating the effectiveness of Sensory Substitution supplemented gait training were identified and included participants with a variety of orthopaedic conditions. Meta-Analyses revealed positive findings of feasibility as well as statistical and clinical effect of the interventions in improving measures of gait speed, weight-bearing control, measures of functionality and subjective self-reporting. Meta-Analyses also revealed the interventions effects were not significant in the management of pain and retention of gait speed. Negatively reinforced Sensory Substitution biofeedback was statistically and clinically effective, whilst positively reinforced biofeedback was not.

Conclusion

For orthopaedic patient populations to improve gait speed, weight-bearing control, functionality, pain and self-report measures, the authors recommend a Sensory Substitution supplemented gait training programme with negative biofeedback on performance. The intervention should be undertaken for 20 min per day, 3 days per week for 5 weeks. The intervention should coincide with structured analgesia administration to facilitate effective pain management. Limitations of the data included some low sample sizes and large age-ranges. No financial support was provided for this study.

Contralateral Lower-Limb Functional Status Before Total Hip Arthroplasty: An Important Indicator for Postoperative Gait Speed

BACKGROUND

Postoperative gait speed, especially comfortable gait speed, is an important factor for predicting function after total hip arthroplasty (THA). In this study, we examined factors related to gait speed, including preoperative lower and upper-limb functional parameters and postoperative lower-limb alignment. In addition, we examined factors related to postoperative good comfortable gait speed (≥1.34 m/s: one indicator of a good clinical outcome). The purpose of this study was to determine if better preoperative functional parameters had a positive effect on postoperative gait speed.

METHODS

This prospective case-control study included 91 patients with hip osteoarthritis who underwent unilateral THA. Patients who had undergone a prior hip surgical procedure or had Crowe type-3 and 4 hips, complications after THA, knee osteoarthritis-related pain, and severe lumbar conditions were excluded. The 1-leg standing time (OLST) and knee extensor strength of the operatively treated side and the contralateral side and the functional reach test were examined preoperatively and at 1 year postoperatively. The leg-length discrepancy and global offset compared with the contralateral side and leg lengthening were examined using 3-dimensional models captured through computed tomographic scans.

RESULTS

The preoperative contralateral side OLST was a significant factor (p < 0.001) for postoperative comfortable gait speed, and the preoperative contralateral-side knee extensor strength was a significant factor (p = 0.018) for postoperative maximum gait speed. Leg-length discrepancy and differences in global offset after THA were not significant factors for postoperative gait speed. The preoperative comfortable gait speed with a cutoff value of 1.115 m/s (area under the receiver operating characteristic curve, 0.690 [95% confidence interval, 0.569 to 0.810]; p = 0.003; sensitivity of 65.5% and specificity of 74.2%) was an independent factor associated with a good postoperative comfortable gait speed. Preoperative contralateral-side OLST was a significant factor (p = 0.027) for preoperative comfortable gait speed.

CONCLUSIONS

The preoperative contralateral-side, lower-limb functional status is a significant factor for postoperative gait speed. Early surgical intervention before the contralateral-side function declines or a preoperative rehabilitation intervention on the contralateral side may improve THA outcome.

LEVEL OF EVIDENCE

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Predicting short stay total hip arthroplasty by use of the timed up and go-test

Background

One of the most important steps before implementing short stay total hip arthroplasty (THA) is establishing patient criteria. Most existing criteria are mainly based on medical condition, but as physical functioning is associated with outcome after THA, we aim to evaluate the added value of a measure of physical functioning to predict short-stay THA.

Methods

We used retrospective data of 1559 patients who underwent an anterior THA procedure. Logistic regression analyses were performed to study the predictive value of preoperative variables among which preoperative physical functioning by use of the Timed Up and Go test (TUG) for short stay THA (< 36 h). The receiver operating characteristic (ROC) curve and Youden Index were used to define a cutoff point for TUG associated with short stay THA.

Results

TUG was significantly associated with LOS (OR 0.84, 95%CI 0.82–0.87) as analyzed by univariate regression analysis. In multivariate regression, a model with the TUG had a better performance with an AUC of 0.77 (95%CI 0.74–0.79) and a R² of 0.27 compared to the basic model (AUC 0.75, 95%CI 0.73–0.77, R² 0.24). Patients with a preoperative TUG less than 9.7 s had an OR of 4.01 (95%CI 3.19–5.05) of being discharged within 36 h.

Conclusions

Performance based physical functioning, measured by the TUG, is associated with short stay THA. This knowledge will help in the decision-making process for the planning and expectations in short stay THA protocols with the advantage that the TUG is a simple and fast instrument to be carried out.

Pre-operative bone mineral density is a predictive factor for excellent early patient-reported outcome measures in cementless total hip arthroplasty using a proximally fixed anatomic stem. A prospective study at two year minimum follow-up

PURPOSE

The goal of the study was to analyze the impact of the pre-operative bone mineral density on the patients' reported outcomes at two year minimum follow-up of cementless THA using a proximally fixed anatomic stem.

METHODS

A prospective study included all patients who underwent a cementless THA using a specific proximally fixed anatomic stem and a 3D preoperative CT scan-based planning. The bone mineral density (BMD) of the metaphyseal cancellous bone was computed in a volume (of 1 mm thick and of 1 cm² surface) at the level of the calcar 10 mm above the top of the lesser trochanter. Patients were assessed at two year follow-up using self-administered auto-questionnaires corresponding to the modified Harris (mHHS), the Oxford (OHS), and the Forgotten Hip (FHS) scores. A multiple linear regression statistical analysis was performed to assess the link between the mHHS, the age, body mass index (BMI), BMD, gender, and ASA grade.

RESULTS

Fifty patients were included (29 men, 21 women), with an average age of 62 ± 12 years and an average BMI of 27 ± 5 kg/m². At two year follow-up, on multivariate analysis, excellent mHHS (≥ 90%) was significantly associated with only two parameters: a BMI ≤ 25 kg /m² with an odd ratio OR = 10 (CI95% [2.1-48.3], p = 0.004) and a BMD ≥ 72 mg/cm³ with an odd ratio OR = 4.87 (CI95% [1.2-18.6], p = 0.02).

CONCLUSION

The short-term PROMs after cementless THA are impacted by pre-operative cancellous bone density. However, the BMI remains the most influential parameter on the clinical outcomes.