The role of small-colony variants in failure to diagnose and treat biofilm infections in orthopedics

Biomaterial-related infection of joint replacements is the second most common cause of implant failure, with serious consequences. Chronically infected replacements cannot be treated without removal of the implant, as the bio film mode of growth protects the bacteria against antibiotics. This review discusses bio film formation on joint replacements and the important clinical phenomenon of small-colony variants (SCVs). These slow-growing phenotypic variants often remain undetected or are misdiagnosed using hospital microbiological analyses due to their unusual morphological appearance and biochemical reactions. In addition, SCVs make the infection difficult to eradicate. They often lead to recurrence since they respond poorly to standard antibiotic treatment and can sometimes survive intracellularly

The influence of computer-assisted surgery on rotational, coronal and sagittal alignment in revision total knee arthroplasty

BACKGROUND: Despite good results of primary total knee arthroplasty (TKA), the number of revision total knee arthroplasties (rTKAs) is rising. Proper implant position is essential, since malposition leads to worse clinical outcome. In rTKA most anatomical landmarks have disappeared because of extensive bone loss, making it more difficult to adequately implant the knee prosthesis. In primary TKA, computer-assisted surgery (CAS) leads to better prosthetic alignment than mechanical navigation guides. Literature about the use of CAS in rTKA is scarce though, and the effect on rotational prosthetic alignment has not been investigated yet. Hence the primary objective of this study is to compare rotational prosthetic alignment when using CAS in rTKA compared to a mechanical navigation guide. Secondary objectives are to compare prosthetic alignment in the coronal and sagittal planes. It is hypothesized that CAS leads to better rotational, coronal and sagittal prosthetic alignment when used during rTKA. METHODS/DESIGN: A prospective clinical intervention study with use of a historical control group will be conducted. Forty-four patients with a minimum age of 18 to be admitted for CAS-rTKA between September 2012 and September 2015 will be included in the intervention group. Forty-four patients with a minimum age of 18 who underwent rTKA with the use of a mechanical navigation guide between January 2002 and April 2012 will form the historical control group. Both groups will be matched according to gender and type of revision prosthesis. Rotational prosthesis alignment will be evaluated using a CT-scan of the knee joint. DISCUSSION: Proper implant position is essential, since malposition leads to worse clinical outcome. Several studies show a significantly positive influence of CAS on prosthetic alignment in primary TKA, but literature about the use of CAS in rTKA is limited. The purpose of this study is thus to investigate the influence of CAS during rTKA on postoperative prosthetic alignment, compared to mechanical navigation guides. TRIAL REGISTRATION: Netherlands National Trial Register NTR351

Responsiveness and interpretability of the pain subscale of the Knee and Hip Osteoarthritis Outcome Scale (KOOS and HOOS) in osteoarthritis patients according to COSMIN guidelines

BACKGROUND: The pain subscales of the Knee and Hip Osteoarthritis Outcome Scores (KOOS and HOOS) are among the most frequently applied, patient reported outcomes to assess pain in osteoarthritis patients and evaluation of the results after Total Knee Arthroplasty (TKA) and Total Hip Arthroplasty (THA). For the evaluation of change over time it is essential to know the responsiveness and interpretability of these measurement instruments. Aim of this study is to investigate responsiveness and interpretability of the KOOS and HOOS pain subscales in patients with knee or hip OA and patients after TKA and THA as recommended by COSMIN guidelines. COSMIN stands for COnsensus based Standards for the selection of health Measurement Instruments. COSMIN recommends methods for assessing responsiveness similar to those assessing validity, using extensive hypothesis testing to assess criterion validity and construct validity of the change score.DESIGN: This clinimetric study was conducted using data obtained from the Duloxetine in OsteoArthritis (DOA) trial. Primary knee or hip osteoarthritis patients were included. During the study, half of the participants received pre-operative targeted treatment with duloxetine, and all participants received TKA or THA. Patients filled out a set of patient-reported outcomes at several time points.METHODS: Using the criterion validity approach the change scores of the KOOS and HOOS pain subscales directly after duloxetine treatment but before TKA and THA were correlated to the Patient Global Improvement anchor-question (PGI-I). Receiver Operating Characteristic curves (ROC curves) were obtained. Using the construct validity approach, hypothesis testing was conducted investigating the correlation between change scores in the KOOS and HOOS pain subscale with change scores in other questionnaires six months after TKA and THA. For interpretability, an anchor-based approach was used to consider the Minimally Important Change (MIC) of the KOOS and HOOS pain subscale. We compared the outcomes after duloxetine treatment and six months after TKA and THA in order to investigate any response shift.RESULTS: Ninety-three participants (53 knee patients and 41 hip patients) were included. Mean change was 4.3 and 4.6 points after conservative treatment for knee and hip OA patients respectively and 31.7 and 48.8 points after TKA and THA respectively. The KOOS and HOOS pain subscales both showed a gradual increase in change scores over the different categories of improvement on the PGI-I, with an Area Under the Curve of 0.72 (95% CI 0.527-0.921) and 0.79 (95% CI 0.588-0.983) respectively. Of the predefined hypotheses, 69% were confirmed for both subscales. The MICs were between 12.2 to 37.9 for the KOOS pain subscale, and between 11.8 to 48.6 for the HOOS pain subscale, depending on whether the PGI-I was administered after conservative treatment, or six months after TKA and THA.CONCLUSIONS: This study endorses the responsiveness of the KOOS and HOOS pain subscales in patients with knee or hip OA and patients after TKA and THA based on construct and criterion validity approaches. The KOOS pain subscale might be able to detect the MIC at an individual level after arthroplasty, but both the KOOS and HOOS pain subscales were not able to do so after conservative treatment. This study is the first to report a considerable response shift in MIC of the KOOS and HOOS pain subscales. This should be taken into consideration when evaluating MIC of the KOOS and HOOS pain subscale after conservative versus operative treatment. Future research should present more reference data regarding MIC scores after different treatments.</p

Subjects with hip osteoarthritis show distinctive patterns of trunk movements during gait-a body-fixed-sensor based analysis

<p>Abstract</p> <p>Background</p> <p>Compensatory trunk movements during gait, such as a Duchenne limp, are observed frequently in subjects with osteoarthritis of the hip, yet angular trunk movements are seldom included in clinical gait assessments. Hence, the objective of this study was to quantify compensatory trunk movements during gait in subjects with hip osteoarthritis, outside a gait laboratory, using a body-fixed-sensor based gait analysis. Frontal plane angular movements of the pelvis and thorax and spatiotemporal parameters of persons who showed a Duchenne limp during gait were compared to healthy subjects and persons without a Duchenne limp.</p> <p>Methods</p> <p>A Body-fixed-sensor based gait analysis approach was used. Two body-fixed sensors were positioned at the dorsal side of the pelvis and on the upper thorax. Peak-to-peak frontal plane range of motion (ROM) and spatiotemporal parameters (walking speed, step length and cadence) of persons with a Duchenne limp during gait were compared to healthy subjects and persons without a Duchenne limp. Participants were instructed to walk at a self-selected low, preferred and high speed along a hospital corridor. Generalized estimating equations (GEE) analyses were used to assess group differences between persons with a Duchenne limp, without a Duchenne limp and healthy subjects.</p> <p>Results</p> <p>Persons with a Duchenne limp showed a significantly larger thoracic ROM during walking compared to healthy subjects and to persons without a Duchenne limp. In both groups of persons with hip osteoarthritis, pelvic ROM was lower than in healthy subjects. This difference however only reached significance in persons without a Duchenne limp. The ratio of thoracic ROM relative to pelvic ROM revealed distinct differences in trunk movement patterns. Persons with hip osteoarthritis walked at a significantly lower speed compared to healthy subjects. No differences in step length and cadence were found between patients and healthy subjects, after correction for differences in walking speed.</p> <p>Conclusions</p> <p>Distinctive patterns of frontal plane angular trunk movements during gait could be objectively quantified in healthy subjects and in persons with hip osteoarthritis using a body-fixed-sensor based gait analysis approach. Therefore, frontal plane angular trunk movements should be included in clinical gait assessments of persons with hip osteoarthritis.</p

Fingerprints of Teaching Interactions:Capturing and Quantifying How Supervisor Regulate Autonomy of Residents in the Operating Room

Objective: Supervisors and residents agree that entrusted autonomy is central to learning in the Operating Room (OR), but supervisors and residents hold different opinions about entrustment: residents regularly experience that they receive insufficient autonomy while supervisors feel their guiding is not appreciated as teaching. These opinions are commonly grounded on general experiences and perceptions, instead of real-time supervisors’ regulatory behaviors as procedures unfold. To close that gap, we captured and analyzed when and to what level supervisors award or restrain autonomy during procedures. Furthermore, we constructed fingerprints, an instrument to visualize entrustment of autonomy by supervisors in the OR that allows us to reflect on regulation of autonomy and discuss teaching interactions. Design: All interactions between supervisors and residents were captured by video and transcribed. Subsequently a multistage analysis was performed: (1) the procedure was broken down into 10 steps, (2) for each step, type and frequency of strategies by supervisors to regulate autonomy were scored, (3) the scores for each step were plotted into fingerprints, and (4) fingerprints were analyzed and compared. Setting: University Medical Centre Groningen (the Netherlands). Participants: Six different supervisor-resident dyads. Results: No fingerprint was alike: timing, frequency, and type of strategy that supervisors used to regulate autonomy varied within and between procedures. Comparing fingerprints revealed that supervisors B and D displayed more overall control over their program-year 5 residents than supervisors C and E over their program-year 4 residents. Furthermore, each supervisor restrained autonomy during steps 4 to 6 but with different intensities. Conclusions: Fingerprints show a high definition view on the unique dynamics of real-time autonomy regulation in the OR. One fingerprint functions as a snapshot and serves a purpose in one-off teaching and learning. Multiple snapshots of one resident quantify autonomy development over time, while multiple snapshots of supervisors may capture best teaching practices to feed train-the-trainer programs

Effect of ACL Reconstruction on Range of Tibial Rotation:A Systematic Review of Current Literature and a Recommendation for a Standard Measuring Protocol

Background: Tibial rotation is an important topic in anterior cruciate ligament (ACL) surgery, and many efforts are being made to address rotational stability. The exact role of the ACL in controlling tibial rotation in clinical studies is unknown. Purpose: To quantify the effect of ACL reconstruction on the amount of tibial rotation based on the current available literature. Study Design: Systematic review; Level of evidence, 4. Methods: A literature search of the PubMed and EMBASE databases was performed in August 2019. Two independent reviewers reviewed titles and abstracts as well as full-text articles. A total of 2383 studies were screened for eligibility. After screening of titles and abstracts, 178 articles remained for full-text assessment. Ultimately, 13 studies were included for analysis. A quality assessment was performed by means of the RoB 2.0 (revised tool for Risk of Bias in randomized trials) and the ROBINS-I (Risk Of Bias In Non-randomized Studies-of Interventions) tools. Results: According to the studies using computer-assisted surgery that were included in this review, ACL reconstruction resulted in an average reduction in tibial rotation of 17% to 32% compared with preoperatively; whether the range of tibial rotation returned to preinjury levels remained unclear. In the current literature, a gold standard for measuring tibial rotation is lacking. Major differences between the study protocols were found. Several techniques for measuring tibial rotation were used, each with its own limitations. Most studies lacked proper description of accompanying injuries. Conclusion: ACL reconstruction reduced the range of tibial rotation by 17% to 32%. Normal values for the range of tibial rotation in patients with ACL deficiency and those who undergo ACL reconstruction could not be provided based on the current available literature owing to a lack of uniform measuring techniques and protocols. Therefore, we advocate uniformity in measuring tibial rotation

Grip strength is strongly associated with height, weight and gender in childhood:a cross sectional study of 2241 children and adolescents providing reference values

QuestionWhat are reference values for grip strength in children and adolescents based on a large and heterogeneous study population? What is the association of grip strength with age, gender, weight, and height in this population?DesignCross-sectional study.ParticipantsParticipants were recruited from schools in the northern provinces of the Netherlands. The study included healthy children and adolescents ranging in age from 4 to 15 years.Outcome measuresAll children had their height (cm) and weight (kg) measured and were allowed a total of four attempts using the Jamar hand dynamometer: twice with each hand. Grip strength scores (kg) were recorded for the dominant and non-dominant hands.ResultsThe study population comprised 2241 children and adolescents. Reference values for both genders are provided according to age and dominance. Grip strength shows a linear and parallel progression for both genders until the age of 11 or 12, after which grip strength development shows an acceleration that is more prominent in boys.ConclusionThere is a significant difference in grip strength with each ascending year of age in favour of the older group, as well as a trend for boys to be stronger than girls in all age groups between 4 and 15 years. Weight and especially height have a strong association with grip strength in children

Young men are at higher risk of failure after ACL hamstring reconstructions:a retrospective multivariate analysis

Background: Results of ACL reconstruction are influenced by both patient and surgical variables. Until now a significant amount of studies have focused on the influence of surgical technique on primary outcome, often leaving patient variables untouched. This study investigates the combined influence of patient and surgical variables through multivariate analysis. Methods: Single-center retrospective cohort study. All patients who underwent primary ACL hamstring reconstruction within a 5-year period were included. Patient characteristics (gender, age, height, weight, BMI at time of surgery) and surgical variables (surgical technique, concomitant knee injury, graft diameter, type of femoral and tibial fixation) were collected. Patients were asked about Tegner Activity Scale (TAS), complications and revision surgery. Multivariate logistic regression was used to study risk factors. First graft failure and potential risk factors (patient and surgical) were univariately assessed. Risk factors with a p-value ≤ 0.05 were included in the multivariate model. Results: Six hundred forty-seven primary ACL hamstring reconstructions were included. There were 41 graft failures (failure rate 6.3%). Patient gender, age, height and preoperative TAS had a significant influence on the risk of failure in the univariate analysis. The multivariate analyses showed that age and sex remained significant independent risk factors. Patients with a failed ACL reconstruction were younger (24.3 vs 29.4 years, OR 0.937), with women at a lower risk for failure of their ACL reconstruction (90.2% males vs 9.8% females, female OR 0.123). ACL graft diameter and other surgical variables aren’t confounders for graft failure. Conclusion: This study shows that patient variables seem to have a larger influence on the failure rate of ACL hamstring reconstructive surgery than surgical variables. Identification of the right patient variables can help us make more informed decisions for our patients and create patient-specific treatment protocols. Young men’s higher risk of failure suggests that these patients may benefit from a different reconstruction technique, such as use of a patellar tendon or combined ligament augmentation. Level of evidence: Retrospective cohort III

Good results at 2-year follow-up of a custom-made triflange acetabular component for large acetabular defects and pelvic discontinuity:a prospective case series of 50 hips

Background and purpose — Custom triflange acetabular components (CTACs) are suggested as good solutions for large acetabular defects in revision total hip arthroplasty. However, high complication rates have been reported and most studies are of limited quality. This prospective study evaluates the performance of a CTAC in patients with large acetabular defects including pelvic discontinuity. Patients and methods — Prospectively collected data of 49 consecutive patients (50 hips), who underwent an acetabular revision with a CTAC were analyzed. Follow-up (FU) was 2 years. The median age of the patients was 68 years (41–89) and 41 were women. Primary outcomes were re-revision of the CTAC and differences between the modified Oxford Hip Score (mOHS) preoperatively and at 2-year follow-up. Secondary outcomes included several patient-reported outcomes (PROMs), radiological results, complications, and a comparison between hips with and without pelvic discontinuity (PD). Results — 1 patient (1 hip) was lost to the 2-year FU. No CTAC needed re-revision. The preoperative and 2-year FU mOHS were available in 40 hips and improved statistically significantly. All of the other secondary outcomes improved over time. 5 hips (of 45 with radiological 2-year FU) had loosening of screws. 8 hips had complications, including 3 persistent wound leakage, 3 pelvic fractures, and 1 dislocation. The mOHS and complication rate were similar in hips with and without PD. Interpretation — Reconstruction of large acetabular defects with and without PD with this CTAC showed good improvement in patient-reported daily functioning, high patient-reported satisfaction, few complications, and no re-revisions at 2-year FU