Role of Routine Suppressive Antibiotic Therapy After Debridement, Antibiotics, and Implant Retention for Acute Periprosthetic Joint Infections

Background

The first-line management strategy for acute periprosthetic joint infections (PJIs) is debridement, antibiotics, and implant retention (DAIR). Suppressive antibiotic therapy (SAT) after DAIR is proposed to improve outcomes, yet its efficacy remains under scrutiny.

Methods

We conducted a multicenter retrospective study in patients with acute PJI of the hip or knee who were treated with DAIR in centers from Europe and the United States. We analyzed the effect of SAT using a Cox model landmarked at 12 weeks. The primary covariate of interest was SAT, which was analyzed as a time-varying covariate. Patients who experienced treatment failure or were lost to follow-up within 12 weeks were excluded from the analysis.

Results

The study included 510 patients with 66 treatment failures with a median follow-up of 801 days. We did not find a statistically significant association between SAT and treatment failure (hazard ratio, 1.37; 95% CI, .79-2.39; P = .27). Subgroup analyses for joint, country cohort, and type of infection (early or late acute) did not show benefit for SAT. Secondary analysis of country cohorts showed a trend toward benefit for the US cohort (hazard ratio, 0.36; 95% CI, .11-1.15; P = .09), which also had the highest risk of treatment failure.

Conclusions

The utility of routine SAT as a strategy for enhancing DAIR's success in acute PJI remains uncertain. Our results suggest that SAT's benefits might be restricted to specific groups of patients, underscoring the need for randomized controlled trials. Identifying patients most likely to benefit from SAT should be a priority in future studies.

Wound drainage after arthroplasty and prediction of acute prosthetic joint infection: prospective data from a multicentre cohort study using a telemonitoring app

Background: Differentiation between uncomplicated and complicated postoperative wound drainage after arthroplasty is crucial to prevent unnecessary reoperation. Prospective data about the duration and amount of postoperative wound drainage in patients with and without prosthetic joint infection (PJI) are currently absent. Methods: A multicentre cohort study was conducted to assess the duration and amount of wound drainage in patients after arthroplasty. During 30 postoperative days after arthroplasty, patients recorded their wound status in a previously developed wound care app and graded the amount of wound drainage on a 5-point scale. Data about PJI in the follow-up period were extracted from the patient files. Results: Of the 1019 included patients, 16 patients (1.6 %) developed a PJI. Minor wound drainage decreased from the first to the fourth postoperative week from 50 % to 3 %. Both moderate to severe wound drainage in the third week and newly developed wound drainage in the second week after a week without drainage were strongly associated with PJI (odds ratio (OR) 103.23, 95 % confidence interval (CI) 26.08 to 408.57, OR 80.71, 95 % CI 9.12 to 714.52, respectively). The positive predictive value (PPV) for PJI was 83 % for moderate to heavy wound drainage in the third week. Conclusion: Moderate to heavy wound drainage and persistent wound drainage were strongly associated with PJI. The PPV of wound drainage for PJI was high for moderate to heavy drainage in the third week but was low for drainage in the first week. Therefore, additional parameters are needed to guide the decision to reoperate on patients for suspected acute PJI.

The Clinical Outcome of Early Periprosthetic Joint Infections Caused by Staphylococcus epidermidis and Managed by Surgical Debridement in an Era of Increasing Resistance

INTRODUCTION

A risk factor for the failure of surgical debridement in patients with early periprosthetic joint infections (PJI) is the presence of multidrug-resistant microorganisms. Staphylococcus epidermidis is one of the most isolated microorganisms in PJI and is associated with emerging resistance patterns. We aimed to assess the antibiotic resistance patterns of S. epidermidis in early PJIs treated with surgical debridement and correlate them to clinical outcomes.

MATERIAL AND METHODS

A retrospective multicentre observational study was conducted to evaluate patients with an early PJI (within 3 months after the index arthroplasty) by S. epidermidis with at least two positive intraoperative cultures. Clinical failure was defined as the need for additional surgical intervention or antibiotic suppressive therapy to control the infection.

RESULTS

A total of 157 patients were included. The highest rate of resistance was observed for methicillin in 82% and ciprofloxacin in 65% of the cases. Both were associated with a higher rate of clinical failure (41.2% vs. 12.5% (p 0.048) and 47.3% vs. 14.3% (p 0.015)), respectively. Furthermore, 70% of the cases had reduced susceptibility to vancomycin (MIC ≥ 2), which showed a trend towards a higher failure rate (39.6% vs. 19.0%, NS). Only 7% of the cases were rifampin-resistant. Only the resistance to fluoroquinolones was an independent risk factor for clinical failure in the multivariate analysis (OR 5.45, 95% CI 1.67-17.83).

CONCLUSION

S. epidermidis PJIs show a high rate of resistance. Resistance to fluoroquinolones is associated with clinical failure. Alternative prophylactic antibiotic regimens and optimising treatment strategies are needed to improve clinical outcomes.

Effect of preoperative duloxetine treatment on postoperative chronic residual pain after total hip or knee arthroplasty: a randomised controlled trial

OBJECTIVES

A key predictor for developing chronic residual pain after total knee or hip arthroplasty (TKA/THA) is sensitisation. Sensitisation can be defined as an 'increased responsiveness of nociceptive neurons in the nervous system'. Aim of this study is to investigate the effects of preoperative treatment with duloxetine in sensitised knee and hip osteoarthritis (OA) patients on postoperative chronic residual pain up to 1 year after arthroplasty.

SETTING

A multicentre, pragmatic, prospective, randomised clinical trial was conducted in three secondary care hospitals in the Netherlands.

PARTICIPANTS

Patients with primary knee/hip OA who were planned for TKA/THA were screened using the modified painDETECT Questionnaire. Patients whose painDETECT score indicated that sensitisation may be present were eligible for participation. 111 participants were included and randomly assigned 1:1 to an intervention or control group. The intervention group received additional duloxetine treatment, the control group did not receive any additional treatment but was allowed to continue with any pain medication they were already taking.

INTERVENTIONS

Preoperative oral treatment for 7 weeks with 60 mg/day of duloxetine was compared with usual care.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcome measure was pain at 6 months after arthroplasty, assessed with the Pain Subscale of the Knee injury and Osteoarthritis Outcome Score (KOOS) or the Hip disability and Osteoarthritis Outcome Score (HOOS) with a 0-100 scale. Secondary outcome measures were Visual Analogue Scale (VAS), and neuropathic-like pain measured using the modified PainDETECT Questionnaire. Longitudinal data collection included time points directly after duloxetine treatment, 1-day preoperatively, and 6 weeks, 6 months and 12 months postoperatively.

RESULTS

Mean improvement in the KOOS/HOOS pain subscale at 6 months postoperatively was 37 (SD 28.1) in the intervention group and 43 (SD 26.5) in the control group. No statistically significant difference was found in change score 6 months postoperatively between the two groups (p=0.280). 12 patients from the intervention group (21%) discontinued duloxetine due to adverse effects.

CONCLUSIONS

Preoperative targeted treatment with duloxetine in end-stage knee and hip OA patients with sensitisation does not influence postoperative chronic residual pain after TKA/THA.

TRIAL REGISTRATION NUMBER

NTR4744.

Model development to study strategies of younger and older adults getting up from the floor

BACKGROUND

Long lies after a fall remain a public health challenge. Many successful fall prevention programmes have been developed but only few of them include recovery strategies after a fall. Once better understood, such movement strategies could be implemented into training interventions.

AIMS

A model of motion sequences describing successful movement strategies for rising from the floor in different age groups was developed. Possible risk factors for poor rising performance such as flexibility and muscle power were evaluated.

METHODS

Fourteen younger subjects between 20 and 50 years of age and 10 healthy older subjects (60+ years) were included. Movement strategies and key components of different rising sequences were determined from video analyses. The temporal parameters of transfers and number of components within the motion sequences were calculated. Possible explanatory variables for differences in rising performance were assessed (leg extension power, flexibility of the knee- and hip joints).

RESULTS

Seven different components were identified for the lie-to-stand-walk transfer, labelled as lying, initiation, positioning, supporting, elevation, or stabilisation component followed by standing and/or walking. Median time to rise was significantly longer in older subjects (older 5.7s vs. younger 3.7s; p < 0.001), and leg extension power (left p = 0.002, right p = 0.013) and knee flexibility (left p = 0.019, right p = 0.025) were significantly lower. The number of components for rising was correlated with hip flexibility (r = 0.514) and maximal power (r = 0.582). The time to rise was correlated with minimal goniometric knee angle of the less flexible leg (r = 0.527) and maximal leg extension power (r = 0.725).

CONCLUSIONS

A motion sequence model containing seven different components identified by individual key-frames could be established. Age-related differences in rising strategies and performance were identified.

Reliability of the Q Force; a mobile instrument for measuring isometric quadriceps muscle strength

Background

The ability to generate muscle strength is a pre-requisite for all human movement. Decreased quadriceps muscle strength is frequently observed in older adults and is associated with a decreased performance and activity limitations. To quantify the quadriceps muscle strength and to monitor changes over time, instruments and procedures with a sufficient reliability are needed. The Q Force is an innovative mobile muscle strength measurement instrument suitable to measure in various degrees of extension. Measurements between 110 and 130° extension present the highest values and the most significant increase after training.

The objective of this study is to determine the test-retest reliability of muscle strength measurements by the Q Force in older adults in 110° extension.

Methods

Forty-one healthy older adults, 13 males and 28 females were included in the study. Mean (SD) age was 81.9 (4.89) years. Isometric muscle strength of the Quadriceps muscle was assessed with the Q Force at 110° of knee extension. Participants were measured at two sessions with a three to eight day interval between sessions. To determine relative reliability, the intraclass correlation coefficient (ICC) was calculated. To determine absolute reliability, Bland and Altman Limits of Agreement (LOA) were calculated and t-tests were performed.

Results

Relative reliability of the Q Force is good to excellent as all ICC coefficients are higher than 0.75. Generally a large 95 % LOA, reflecting only moderate absolute reliability, is found as exemplified for the peak torque left leg of −18.6 N to 33.8 N and the right leg of −9.2 N to 26.4 N was between 15.7 and 23.6 Newton representing 25.2 % to 39.9 % of the size of the mean. Small systematic differences in mean were found between measurement session 1 and 2.

Conclusion

The present study shows that the Q Force has excellent relative test-retest reliability, but limited absolute test-retest reliability. Since the Q Force is relatively cheap and mobile it is suitable for application in various clinical settings, however, its capability to detect changes in muscle force over time is limited but comparable to existing instruments.

Changes of Body Composition, Muscular Strength and Physical Performance Due to Resistance Training in Older Persons with Sarcopenic Obesity

BACKGROUND

At present, it is unclear whether older, obese persons with or without sarcopenia respond differently to training. Furthermore, there are no differentiated recommendations for resistance training for this special target group.

OBJECTIVES

The objectives are to investigate the changes in the physical parameters of older, obese men caused by training and to reappraise the modalities of resistance training for older persons.

DESIGN

Pre-test-post-test design.

PARTICIPANTS

The participants were 33 physically inactive and obese older men (≥ 65 years, BMI ≥30 kg/m2), with-out severe diseases. Subjects were divided into two groups: NSAR (no or presarcopenia, n= 15) or SAR (sarcopenia, n= 18).

INTERVENTION

The intervention consisted of progressive resistance training, twice a week for 16 weeks with finally 80-85% of maximum strength and three sets with 8-12 repetitions. The training contained six exercises for the major muscle groups.

MEASUREMENTS

Sarcopenia was assessed using the Short Physical Performance Battery (SPPB), hand-grip strength, skeletal muscle mass index (SMI), and gait speed over a 6-meter walkway. Furthermore, the maximum dynamic strength (1 RM) was assessed.

RESULTS

At baseline, the NSAR group had significantly better values in SMI, SPPB score, hand-grip strength, and 1 RM. After training, the results in both groups displayed an increase in 1 RM at the lower limbs (NSAR 18%, SAR 38%) and the upper limbs (NSAR 12%, SAR 14%). Also, the SPPB score (NSAR 11%, SAR 15%) and the 6-m-gait speed (NSAR 5%, SAR 10%) increased. The SAR group was able to increase their right hand-grip strength by 12%, whereas the NSAR group maintained their initial high strength values. SMI did not change in both groups.

CONCLUSIONS

Both groups show improvements after resistance training with slightly more benefits for men with sarcopenia. Results of this study can be used to define specific training regimens for N(SAR) subjects.

Fall detection with body-worn sensors : a systematic review

BACKGROUND AND AIMS

Falls among older people remain a major public health challenge. Body-worn sensors are needed to improve the understanding of the underlying mechanisms and kinematics of falls. The aim of this systematic review is to assemble, extract and critically discuss the information available in published studies, as well as the characteristics of these investigations (fall documentation and technical characteristics).

METHODS

The searching of publically accessible electronic literature databases for articles on fall detection with body-worn sensors identified a collection of 96 records (33 journal articles, 60 conference proceedings and 3 project reports) published between 1998 and 2012. These publications were analysed by two independent expert reviewers. Information was extracted into a custom-built data form and processed using SPSS (SPSS Inc., Chicago, IL, USA).

RESULTS

The main findings were the lack of agreement between the methodology and documentation protocols (study, fall reporting and technical characteristics) used in the studies, as well as a substantial lack of real-world fall recordings. A methodological pitfall identified in most articles was the lack of an established fall definition. The types of sensors and their technical specifications varied considerably between studies.

CONCLUSION

Limited methodological agreement between sensor-based fall detection studies using body-worn sensors was identified. Published evidence-based support for commercially available fall detection devices is still lacking. A worldwide research group consensus is needed to address fundamental issues such as incident verification, the establishment of guidelines for fall reporting and the development of a common fall definition.

Proposal for a multiphase fall model based on real-world fall recordings with body-fixed sensors

Falls are by far the leading cause of fractures and accidents in the home environment. The current Cochrane reviews and other systematic reviews report on more than 200 intervention studies about fall prevention. A recent meta-analysis has summarized the most important risk factors of accidental falls. However, falls and fall-related injuries remain a major challenge. One novel approach to recognize, analyze, and work better toward preventing falls could be the differentiation of the fall event into separate phases. This might aid in reconsidering ways to design preventive efforts and diagnostic approaches. From a conceptual point of view, falls can be separated into a pre-fall phase, a falling phase, an impact phase, a resting phase, and a recovery phase. Patient and external observers are often unable to give detailed comments concerning these phases. With new technological developments, it is now at least partly possible to examine the phases of falls separately and to generate new hypotheses.The article describes the practicality and the limitations of this approach using body-fixed sensor technology. The features of the different phases are outlined with selected real-world fall signals.

Automated approach for quantifying the repeated sit-to-stand using one body fixed sensor in young and older adults

Much is known about the sit-to-stand (STS) and its biomechanics. Currently, however, there is little opportunity for instrumented quantification of the STS as part of screening or diagnosis in clinical practice. The objectives of the present study were to describe the feasibility of using an automated approach for quantifying the STS using one sensor location and to start testing the discriminative validity of this approach by comparing older and younger adults. 15 older subjects recruited from a residential care home and 16 young adults performed 5 repeated sit-to-stand and stand-to-sit movements. They were instrumented with a small and lightweight measurement system (DynaPort(®)) containing 1 triaxial seismic accelerometer and 3 uniaxial gyroscopes fixed in a belt around the waist. Durations of the (sub-)phases of the STS were analyzed and maximum angular velocities were determined. All successful STS cycles were automatically detected without any errors. The STS duration in the older adults was significantly longer and more variable in all phases (i.e., sit-to-stand, standing, stand-to-sit and sitting) compared to the young adults. Older adults also exhibited lower trunk flexion angular velocity. The results of this first fully automated analysis of instrumented repeated STS movements demonstrate that several STS parameters can be identified that provide a basis for a more precise, quantitative study of STS performance in clinical practice.

Distance to achieve steady state walking speed in frail elderly persons

This study aims to determine the length of the gait initiation phase before achieving steady state walking in frail older people. Based on body fixed sensors, habitual walking was analysed in 116 community-dwelling older persons (mean age 83.1 years, 84% women). The start of steady state walking was identified using an algorithm taking into account speeds from consecutive strides. On average, participants reached a walking speed of 0.66 m/s after an acceleration phase of 1.43 m (89% after 2.47 m). When spatio-temporal variables were calculated from 4, 6, 8, 10, or 20 consecutive stride cycles after achieving steady state, similar values were observed for mean gait speed and stride length. The variability of these factors differed depending on the number of gait cycles. Assessments of steady state gait in frail elderly people should therefore exclude the first 2.5m of walking. If gait variability is to be assessed, it is recommended that more than 20 stride cycles be used.

Determining the centre of pressure during walking and running using an instrumented treadmill

In this paper, a new method of determining spatial and temporal gait parameters by using centre of pressure (CoP) data is presented. A treadmill is used which was developed to overcome limitations of regular methods for the analysis of spatio-temporal gait parameters and ground reaction forces during walking and running. The design of the treadmill is based on the use of force transducers underneath a separate left and right plate, which together form the treadmill walking surface. The results of test procedures and measurements show that accurate recordings of vertical ground reaction force can be obtained. These recordings enable a separate analysis of vertical ground reaction forces during double support phases in walking, and the analysis of changes in the centre of pressure (CoP) position during subsequent foot placements. From the CoP data, temporal gait parameters (e.g. duration of left/right support and swing phases) and spatial gait parameters (i.e. left/right step lengths and widths) can be derived.

Prevention of Falls Network Europe: a thematic network aimed at introducing good practice in effective falls prevention across Europe

The Prevention of Falls Network Europe (ProFaNE) aims to improve quality of life of the ageing population by focussing on a major cause of disability and distress: falls. The thematic network is funded by the European Commission and brings together scientists, clinicians and other health professionals from around Europe to focus on four main themes: taxonomy and coordination of trials, clinical assessment and management of falls, assessment of balance function, and psychological aspects of falling. There are 24 members across Europe as well as network associates who contribute expertise at workshops and meetings. ProFaNE, a 4-year project which started in January 2003, aims to improve and standardise health care processes, introducing and promoting good practice widely across Europe. ProFaNE undertakes workshops that bring together experts and observers around specific topics to exchange knowledge, expertise and resources on interventions that reduce falls. A key document for policy makers around Europe, written by ProFaNE members, was published by the World Health Organisation in March 2004. ProFaNE's website has both public and private areas with resources (web links to falls prevention, useful documents for policy makers, researchers and practitioners) and a discussion board to encourage informal networking between members and the public. The ultimate aim of ProFaNE is to submit a collaborative bid to undertake a multi-centre, randomised controlled trial of a multi-factorial fall prevention intervention with peripheral fracture as the primary outcome. The success of the networking and relationship building in the first year and a half of ProFaNE's work makes this an achievable goal.

Leg muscle activation during gait in Parkinson's disease: adaptation and interlimb coordination

Adaptation in leg muscle activity and coordination between lower limbs were studied during walking on a treadmill with split belts in one group of parkinsonian patients and one of age-matched healthy subjects. Four different belt speeds (0.25/0.5/0.75/1.0 m/sec) were applied in selected combinations to the left and right leg. While these walking conditions were easily tolerated by the healthy subjects, the parkinsonian patients usually reached the limits of their walking capabilities. Both groups adapted automatically to a change in belt speed within approximately 20 stride cycles. Healthy subjects adapted by reorganizing their stride cycle with a relative shortening of duration of support and lengthening of the swing phase of the "fast" leg and vice versa on the "slow" leg. The patients showed a restricted range of stride frequencies for the various belt speeds during normal and split-belt walking with consequent deviations in the reorganization of the stride cycle. In both healthy subjects and patients, ipsilateral gastrocnemius and contralateral tibialis anterior electromyographic (EMG) activity increased predominantly with an ipsilateral increase in belt speed. Two main differences were observed in the EMG patterns: (1) In the patients leg muscle EMG activity was less modulated and gastrocnemius EMG amplitude was small during normal and split-belt walking. However, there was no significant difference between the two groups in respect to the reorganization of the EMG pattern required for the various split-belt walking conditions. (2) The amount of co-activation of antagonistic leg muscles during the support phase of the stride cycle was greater in the patients compared to the healthy subjects during normal and split-belt walking. It is suggested that reduced EMG modulation and recruitment in the leg extensors may contribute to the impaired walking of the patients. This in turn is a result of an impaired proprioceptive feedback from extensor load receptors. This defective control is partially compensated for in parkinsonian patients by a greater amount of leg flexor activation which leads to a higher degree of co-activation. Visual input plays a role in the control of this increased activation.

Adaptational and learning processes during human split-belt locomotion: interaction between central mechanisms and afferent input

Split-belt locomotion (i.e., walking with unequal leg speeds) requires a rapid adaptation of biomechanical parameters and therefore of leg muscle electromyographic (EMG) activity. This adaptational process during the first strides of asymmetric gait as well as learning effects induced by repetition were studied in 11 healthy volunteers. Subjects were switched from slow (0.5 m/s) symmetric gait to split-belt locomotion with speeds of 0.5 m/s and 1.5 m/s, respectively. All subjects were observed to adapt in a similar way: (1) during the first trial, adaptation required about 12-15 strides. This was achieved by an increase in stride cycle duration, i.e., an increase in swing duration on the fast side and an increase in support duration on the slow side. (2) Adaptation of leg extensor and flexor EMG activity paralleled the changes of biomechanical parameters. During the first strides, muscle activity was enhanced with no increase in coactivity of antagonistic leg muscles. (3) A motor learning effect was seen when the same paradigm was repeated a few minutes later--interrupted by symmetric locomotion--as adaptation to the split-belt speeds was achieved within 1-3 strides. (4) This short-time learning effect did not occur in the "mirror" condition when the slow and fast sides were inverted. In this case adaptation again required 12-15 strides. A close link between central and proprioceptive mechanisms of interlimb coordination is suggested to underlie the adaptational processes during split-belt conditions. It can be assumed that, as in quadrupedal locomotion of the cat, human bipedal locomotion involves separate locomotor generators to provide the flexibility demanded. The present results suggest that side-specific proprioceptive information regarding the dynamics of the movement is necessary to adjust the centrally generated locomotor activity for both legs to the actual needs for controlled locomotion. Although the required pattern is quickly learned, this learning effect cannot be transferred to the contralateral side.

Human neuronal interlimb coordination during split-belt locomotion

Human interlimb coordination and the adaptations in leg muscle activity were studied during walking on a treadmill with split belts. Four different belt speeds (0.5, 1.0, 1.5, 2.0 m/s) were offered in all possible combinations for the left and right leg. Subjects adapted automatically to a difference in belt speed within 10-20 stride cycles. This adaptation was achieved by a reorganization of the stride cycle with a relative shortening of the duration of the support and lengthening of the swing phase of the "fast" leg and, vice versa, in support and swing duration on the "slow" leg. The electromyogram EMG patterns were characterized by two basic observations: (1) onset and timing of EMG activity were influenced by biomechanical constraints. A shortening of the support phase on the faster side was related to an earlier onset and increase in gastrocnemius activity, while a coactivation pattern in the antagonistic leg muscles was predominant during a prolonged support phase on the slower side. (2) A differential modulation of the antagonistic leg muscles took place. An increase in ipsilateral belt speed in combination with a constant contralateral belt speed was associated with an almost linear increase in ipsilateral gastrocnemius and contralateral tibialis anterior EMG activity, while the contralateral gastrocnemius and ipsilateral tibialis anterior EMG activity were little affected. It is concluded that a modifiable timing within the stride cycle takes place with a coupling between ipsilateral support and contralateral swing phase. The neuronal control of this coupling is obviously based on ipsilateral modulation of leg extensor EMG by proprioceptive feedback and an appropriate central (e.g. spinal) modulation of contralateral tibialis anterior EMG activity.