Increased temporal binding during voluntary motor task under local anesthesia.

Temporal binding refers to a systemic bias in the perceived time interval between two related events, most frequently voluntary motor actions and a subsequent sensory effect. An inevitable component of most instrumental motor actions is tactile feedback. Yet, the role of tactile feedback within this phenomenon remains largely unexplored. Here, we used local anesthesia of the index finger to temporarily inhibit incoming sensory input from the finger itself, while participants performed an interval-estimation task in which they estimated the delay between a voluntary motor action (button press) and a second sensory event (click sound). Results were compared to a control condition with intact sensation. While clear binding was present in both conditions, the effect was significantly enhanced when tactile feedback was temporarily removed via local anesthesia. The results are discussed in light of current debates surrounding the underlying mechanisms and function of this temporal bias.

Posttraumatic Osteoarthritis of the Distal Interphalangeal Joint: A Follow-Up Study of 12 Years After Nonsurgical Treatment of Mallet Finger Fractures.

PURPOSE: In treatment of mallet finger fractures (MFFs), the aim is to minimize residual extension lag, reduce subluxation, and restore congruency of the distal interphalangeal (DIP) joint. Failure to do so may increase the risk of secondary osteoarthritis (OA). However, long-term follow-up studies focusing on OA of the DIP joint after an MFF are scarce. The purpose of this study was to assess OA, functional outcomes, and patient-reported outcome measures (PROMs) after an MFF. METHODS: A cohort study was performed with 52 patients who sustained an MFF at a mean of 12.1 years (range, 9.9-15.5 years) previously and who were treated nonsurgically. A healthy contralateral DIP joint was used as the control. Outcomes were radiographic OA, using the Kellgren and Lawrence and Osteoarthritis Research Society International classifications, range of motion, pinch strength, and PROMs (Patient-Rated Wrist Hand Evaluation, Quick Disabilities of the Arm, Shoulder, and Hand, Michigan Hand Outcome Questionnaire, 12-item Short Form Health Survey). Radiographic OA was correlated with PROMs and functional outcomes. RESULTS: At follow-up, there was an increase in OA in 41% to 44% of the MFFs. Of all the MFFs, 23% to 25% showed a higher degree of OA than the healthy control DIP joint. Range of motion (mean difference ranging from -6° to -14°) and Michigan Hand Outcome Questionnaire score (median difference, -1.3) were decreased after MFFs but not to a clinically relevant extent. Radiographic OA was weakly to moderately correlated with functional outcomes and PROMs. CONCLUSIONS: Radiological OA after an MFF is similar to the natural degenerative process in the DIP joint and is accompanied by a decrease in range of motion of the DIP joint, which does not clinically affect PROMs. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Active monitoring versus an abduction device for treatment of infants with centered dysplastic hips: study protocol for a randomized controlled trial (TReatment with Active Monitoring (TRAM)-Trial).

BACKGROUND: Developmental Dysplasia of the Hip (DDH) is one of the most common pediatric orthopedic disorders, affecting 1-3% of all newborns. The optimal treatment of centered DDH is currently under debate. This randomized controlled trial aims to study the (cost-)effectiveness of active monitoring versus abduction treatment for infants with centered DDH. METHODS: This is a multicenter, parallel-group, open-label, non-inferiority randomized controlled trial studying the (cost-)effectiveness of active monitoring versus abduction treatment for infants with centered DDH in fourteen hospitals in the Netherlands. In total, 800 infants with centered DDH (Graf IIa-/IIb/IIc), aged 10-16 weeks, will be randomly allocated to the active monitoring or abduction treatment group. Infants will be followed up until the age of 24 months. The primary outcome is the rate of normal hips, defined as an acetabular index lower than 25 degrees on an antero-posterior radiograph, at the age of 12 months. Secondary outcomes are the rate of normal hips at the age of 24 months, complications, time to hip normalization, the relation between baseline patient characteristics and the rate of normal hips, compliance, costs, cost-effectiveness, budget impact, health-related quality of life (HRQoL) of the infant, HRQoL of the parents/caregivers, and parent/caregiver satisfaction with the treatment protocol. DISCUSSION: The outcomes of this randomized controlled trial will contribute to improving current care-as-usual for infants with centered DDH. TRIAL REGISTRATION: Dutch Trial Register, NL9714, registered September 6, 2021. https://clinicaltrialregister.nl/en/trial/29596.

Three-dimensional printed customized versus conventional plaster brace for trapeziometacarpal osteoarthritis: a randomized controlled crossover trial.

We investigated the non-operative management of trapeziometacarpal osteoarthritis with a three-dimensional (3-D) printed patient-customized brace compared with a conventional plaster brace. Fifty-two patients with symptomatic trapeziometacarpal osteoarthritis were enrolled in a 9-week crossover study, which was designed as a randomized controlled trial of two periods of 4-week brace therapies. The primary outcome was patient satisfaction measured with the Dutch version of the Quebec User Evaluation of Satisfaction with Assistive Technology questionnaire survey. Secondary outcomes included pain, patient-reported function, functional hand strength measured by pinch and grip strength, and compliance assessed through a daily log of self-reported brace usage. The 3-D printed patient-customized brace had higher patient satisfaction and compliance than the conventional plaster brace. Patients preferred the 3-D printed customized brace (93%) rather than the conventional plaster brace (7%). This suggests that the 3-D printed patient-customized brace is effective in the non-operative management of trapeziometacarpal osteoarthritis.Level of evidence: I.

Risk Factors for Musculoskeletal Injury in CrossFit: A Systematic Review.

The objective of this systematic review was to identify potential risk factors for injury in CrossFit participants. Embase, Medline, Web of Science, Cochrane, CINAHL, Google Scholar, and SportDiscuss databases were all searched up to June 2021. Cohort studies that investigated risk factors for CrossFit injuries requiring medical attention or leading to time loss in sports were included. A best-evidence synthesis was performed combining all the outcomes from prospective cohort studies. From 9,452 publications identified, we included three prospective cohort studies from which two had a low risk of bias and one a high risk of bias. The studies examined 691 participants of whom 172 sustained an injury. There was limited evidence that switching between prescribed and scaled loads during training is associated with increased injury risk and that increased duration of participation is a protective factor for injury. This could mean that novice CrossFit athletes and those increasing their training load should have closer supervision by CrossFit coaches. These risk factors should be considered when developing preventive interventions.

Early migration in unicompartmental knee arthroplasty: a radiostereometric study of 26 patients with 24 months of follow-up.

BACKGROUND AND PURPOSE: Aseptic loosening, mainly caused by migration, is one of the most common indications for revisions in unicompartmental knee arthroplasty (UKA). In this study, we investigated the early migration of the Persona Partial Knee (PPK, Zimmer Biomet, Warsaw, IN), a cemented medial fixed-bearing unicompartmental knee prosthesis, and evaluated the clinical results. PATIENTS AND METHODS: 26 primary PPKs were implanted. Radiographs were obtained direct postoperatively, at 6 weeks, 6, 12 and 24 months postoperatively. Migration of the femoral and tibial component was calculated using model-based radiostereophotogrammetric analysis (mRSA) in terms of translations and rotations. Patient-reported outcome measures (PROMs) were also registered. RESULTS: At 24 months postoperatively, we found low migration of both the femoral and tibial component in the first 6 months, after which both components stabilized. Only the rotation of the tibial component about the z-axis did not stabilize. All PROMs improved after 24 months compared with preoperative PROMs. CONCLUSION: The Persona Partial Knee shows low migration of both the femoral and tibial component and PROMs were improved at 24 months follow-up. Long-term follow-up is needed to investigate the performance of the prosthesis compared with other prostheses.

Psychometric qualities of the patient rated Wrist/Hand evaluation (PRWHE) in dutch primary care patients with wrist complaints.

BACKGROUND: Knowledge on the course, disability and functionality of wrist complaints is still compendious in primary care guidelines, despite the high prevalence in primary care. Valid questionnaires can facilitate the monitoring of patients in primary care and research initiatives. In this study, we aimed to study the psychometric qualities of the Dutch version of the Patient Rated Wrist/Hand Evaluation (PRWHE-DLV) among adults with (sub)acute wrist complaints in primary care. METHODS: An observational cohort of 35 adults with (sub)acute wrist complaints in Dutch primary care was established. The content validity of the PRWHE-DLV was validated by assessing the floor and ceiling effects at baseline (T0). Reproducibility was assessed by the test-retest reliability between T0 and T1 (2-5 days after T0), using the Intra-class Correlation Coefficient. The construct validity was assessed based on the correlation between the PRWHE-DLV and the Quick-DASH, Physical Component Score (SF-12), VAS-function, Physical Functioning (SF-12), VAS-pain and Bodily Pain (SF-12) at T0. Responsiveness was defined as the ability of the PRWHE-DLV to measure change 3 weeks after T0 (internal) and the relation of these changes to clinically important outcomes (external). RESULTS: Psychometric qualities of the PRWHE-DLV demonstrated high content validity with no floor or ceiling effects, excellent reliability (Intra-class correlation coefficient = 0.90; 95% CI 0.80-0.95), high construct validity with the validated Quick-DASH and VAS score (r = 0.85 with Quick-DASH, r = 0.75 with VAS-function and r = 0.78 with VAS-pain) and high responsiveness. CONCLUSION: The PRWHE-DLV provided reliable and adequate information for primary care clinical practice.

Is Early Active Motion After 3-Ligament Tenodesis Noninferior to Late Active Motion? A Prospective, Multicenter Cohort Study.

PURPOSE: If early active motion after 3-ligament tenodesis is safe, it may yield more patient comfort and an early return to activities. Therefore, the aim of this study was to investigate whether early active motion is noninferior to late active motion after 3-ligament tenodesis for scapholunate interosseous ligament injuries. METHODS: This prospective, multicenter cohort study, using a noninferiority design with propensity score matching, compared a late active motion protocol (immobilization for 10-16 days, wrist therapy in weeks 5-6) with an early active motion protocol (immobilization for 3-5 days, wrist therapy during week 2). Patients who were older than 18 years, had complete baseline information on demographics, and underwent 3-ligament tenodesis were included. The outcome measures were postoperative Patient-Reported Wrist/Hand Evaluation scores, pain, complications, return to work, range of motion, grip strength, and satisfaction with treatment results at 3 months of follow-up. RESULTS: After propensity matching, a total of 108 patients were included. Patient-Reported Wrist/Hand Evaluation and pain scores during physical load following an early active motion protocol were noninferior compared with scores following a late active motion protocol. Furthermore, early active motion did not lead to an increase of complications, differences in range of motion or grip strength, or less satisfaction with the treatment result. An earlier return to work was not observed. CONCLUSIONS: Early active motion leads to noninferior results without more complications as compared with late active motion. Based on these findings, early active motion can be considered safe, and might be recommended due to its potential benefits compared with late active motion after 3-ligament tenodesis. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic III.

Active monitoring versus immediate abduction as treatment of stable developmental dysplasia of the hip: a systematic review of the literature.

OBJECTIVES: This systematic review aims to compare the effects of active monitoring and abduction treatment on the Graf alpha angle, Acetabular Index (AI) and femoral head coverage in infants with stable developmental dysplasia of the hip (DDH). DESIGN: Systematic review reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. DATA SOURCES: A search of the PubMed, Embase, Cochrane and Web of Science databases was performed in January 2020 and updated in January 2021. ELIGIBILITY CRITERIA: (Non-)randomised studies comparing active monitoring with abduction treatment in infants younger than 4 months with stable DDH were included. DATA EXTRACTION AND SYNTHESIS: All eligible articles were methodologically assessed using the Cochrane risk of bias tools. Data were extracted by summarising the study characteristics and results. RESULTS: Of the six included studies, two randomised studies were of low risk and two of some concerns. Two non-randomised studies were of serious risk. In total, 544 dysplastic hips (439 infants) were investigated, of which 307 were observed and 237 were treated. Two studies reported a faster improvement of the alpha angle and average acetabular coverage in treated hips at 3 months. No differences in AI between the treatment and observation group after 3 months were reported. In total, 38 infants (12%) in the observation group switched to the treatment group. At the final radiograph, 21 observed hips and 32 treated hips were dysplastic. CONCLUSIONS: There were no differences in AI between the treatment and observation group after 3 months in infants up to 4 months of age with stable DDH hips. The switch of 38 infants (12%) from the observation to the treatment group corroborates that not all infantile DDH hips will spontaneously progress into normal hips. The small study population sizes and methodological heterogeneity warrant a large randomised controlled trial to study this research question. PROSPERO REGISTRATION NUMBER: CRD4202123300.

Is Midcarpal Arthroscopy for Suspected Scapholunate Pathology Associated With Greater Interobserver Agreement and More Frequent Offer of Surgery?

PURPOSE: This study compared the interobserver agreement of arthroscopic classification of suspected scapholunate interosseous ligament (SLIL) pathology with and without midcarpal arthroscopy to help inform diagnostic strategies. It also measured the association of midcarpal arthroscopy with recommendations for reconstructive surgery. The association of midcarpal arthroscopy with the type of surgery recommended was also studied. METHODS: Fourteen consecutive videos of diagnostic radiocarpal and midcarpal wrist arthroscopy for suspected SLIL pathology were selected. An international survey-based experiment was conducted among upper extremity surgeons of the Science of Variation Group. Participants were randomized to view either radiocarpal arthroscopic videos or radiocarpal and midcarpal videos. Surgeons rated SLIL pathology according to the Geissler classification and recommended surgical or nonsurgical treatment. If surgical treatment was recommended, they indicated the type of procedure. RESULTS: The interobserver agreement for the Geissler classification was slight/fair for observers who reviewed midcarpal and radiocarpal videos and for those who viewed radiocarpal videos only. Viewing midcarpal videos was associated with higher pathology grades, the recommendation for reconstructive surgery, and a preference for tenodesis over scapholunate ligament repair. CONCLUSIONS: Diagnostic wrist arthroscopy for a wrist with normal radiological alignment has poor interobserver agreement. CLINICAL RELEVANCE: The pursuit of a pathology that accounts for wrist symptoms in a nonspecific interview and examination and normal radiographs is understandable; however, the low reliability of the scapholunate pathology of diagnostic arthroscopy might be associated with more potential harm than benefit.

Treatment Recommendations for Suspected Scapholunate Ligament Pathology.

Background The diagnosis and treatment of scapholunate interosseous ligament (SLIL) pathology is debated and notably variable. This study assessed the influence of diagnostic arthroscopy on treatment recommendations and the interobserver reliability of the arthroscopic classification of SLIL pathology. Methods The influence of diagnostic arthroscopy on treatment recommendations and the reliability of the arthroscopic classification of SLIL pathology were tested in a survey-based experiment. Seventy-seven surgeons evaluated 16 scenarios of people with wrist pain with variation in symptoms, scaphoid shift, time of symptom onset, and MRI appearance of the SLIL. Participants were randomized to view or not to view diagnostic wrist arthroscopy. Factors associated with recommendation for repair, capsulodesis, or tenodesis were analyzed. Results Viewing arthroscopic videos was associated with both offering surgery and a more reconstructive option. Other factors independently associated with recommendation for surgery included greater pain intensity and activity intolerance, women surgeons, an asymmetric scaphoid shift, and a recent onset of symptoms. The interobserver reliability of SLIL classification was slight. Conclusions Diagnostic arthroscopy leads to more surgery, and more invasive surgery, in spite of unreliable assessment of pathology. Clinical Relevance This points to the need to measure the potential benefits and harms of diagnostic wrist arthroscopy among people with wrist pain and no clear diagnosis on interview, examination, and radiographs. Level of Evidence Not applicable.

Early fixation of the humeral component in stemless total shoulder arthroplasty : a radiostereometric and clinical study with 24-month follow-up.

AIMS: Stemless humeral implants have been developed to overcome stem-related complications in total shoulder arthroplasty (TSA). However, stemless implant designs may hypothetically result in less stable initial fixation, potentially affecting long-term survival. The aim of this study is to investigate early fixation and migration patterns of the stemless humeral component of the Simpliciti Shoulder System and to evaluate clinical outcomes. METHODS: In this prospective cohort study, radiostereometric analysis (RSA) radiographs were obtained in 24 patients at one day, six weeks, six months, one year, and two years postoperatively. Migration was calculated using model-based RSA. Clinical outcomes were evaluated using the visual analogue scale (VAS), the Oxford Shoulder Score (OSS), the Constant-Murley Score (CMS), and the Disabilities of the Arm, Shoulder and Hand (DASH) score. RESULTS: At two years, median translation along the x-, y-, and z-axis was -0.12 mm (interquartile range (IQR) -0.18 to 0.02), -0.17 mm (IQR -0.27 to -0.09), and 0.09 mm (IQR 0.02 to 0.31). Median rotation around the x-, y-, and z-axis was 0.12° (IQR -0.50 to 0.57), -0.98° (IQR -1.83 to 1.23), and 0.09° (IQR -0.76 to 0.30). Overall, 20 prostheses stabilized within 12 months postoperatively. Four prostheses showed continuous migration between 12 and 24 months. At two-year follow-up, with the exception of one revised prosthesis, all clinical scores improved significantly (median VAS difference at rest: -3.0 (IQR -1.5 to -6.0); OSS 22.0 (IQR 15.0 to 25.0); CMS 29.5 (IQR 15.0 to 35.75); and DASH -30.0 (IQR -20.6 to -41.67) (all p < 0.001)) with the exception of one revised prosthesis. CONCLUSION: In conclusion, we found that 20 out of 24 implants stabilized within 12 months postoperatively. The significance of continuous migration in four implants is unclear and future research on the predictive value of early migration for future loosening in TSA is required. Clinical results revealed a clinically relevant improvement. Cite this article: Bone Joint J 2022;104-B(1):76-82.

External validation of the Almelo Hip Fracture Score, a prediction model for early mortality following hip fracture surgery.

PURPOSE: Early mortality (< 30 days) in hip fracture patients is as high as 9.6%. Several risk assessment tools have been developed to identify patients at high risk for early mortality. Among them, the Almelo Hip Fracture Score (AHFS) was developed recently and showed promising results. Until now, this tool has not been validated; therefore, we aim to perform an external validation of the AHFS. METHODS: On admission, AHFS variables were prospectively collected. The prospectively collected data were used retrospectively to externally validate the AHFS in a cohort of hip fracture patients that were admitted to a hospital in Delft (Delft cohort). The AHFS score was retrospectively calculated for all hip fracture patients meeting the inclusion criteria. The characteristics of the Delft Cohort, AHFS score, sensitivity, specificity, positive predictive value, negative predictive value, and area under the curve were calculated and compared to the original Almelo cohort, in which the AHFS was developed. RESULTS: 422 patients of 70 years and older were included. Mortality within 30 days was 7.6% and similar to the 7.5% observed in the Almelo cohort. For the high-risk cut-off point, specificity was 95.4% in the Delft Cohort vs. 92.5% in the Almelo Cohort, and sensitivity for the low-risk cut-off point was 75.9 vs. 78.1% in the Almelo Cohort. The area under the ROC curve was 0.70 (95% CI 0.60-0.79) compared to 0.82 in the Almelo cohort. CONCLUSIONS: The validity of the score was acceptable and comparable to the values in the Almelo cohort. This score might be used to identify patients at high risk for early mortality.

Hip Arthroscopy for Femoroacetabular Impingement Syndrome Results in 2 Recovery Patterns Based on Preoperative Pain and on Arthritis: Improvers and Non-improvers.

PURPOSE: To analyze whether subgroups of patients could be distinguished with different functional recovery trajectories after hip arthroscopy for femoroacetabular impingement (FAI) syndrome and to identify differences between those subgroups using data from our prospective cohort registration. METHODS: We retrospectively reviewed the prospectively registered data of patients who had undergone hip arthroscopy for FAI syndrome in our clinic from 2015 through 2018. Latent class growth modeling and growth mixture modeling were used to identify and classify groups of patients according to the trajectory of functional recovery using the Hip Outcome Score-Activities of Daily Life (HOS-ADL). We used univariable analysis and descriptive statistics to explore whether differences in group membership could be identified. RESULTS: A total of 100 patients were analyzed. Growth mixture modeling identified 2 main types of recovery pattern after surgery: patients in whom the HOS-ADL improved significantly after surgery to 90, whom we called the "improvers" (with fast initial improvement within 3 months that is maintained during follow-up), and patients who did not significantly benefit from surgery (with only mild improvement in the HOS-ADL at 3 months and no further change during follow-up), whom we called the "non-improvers." Univariable analysis and comparison of differences between subgroups showed higher preoperative visual analog scale scores for pain and more intraoperative arthrosis of the femoral head for the non-improvers. CONCLUSIONS: We identified 2 main types of recovery pattern after arthroscopic treatment of FAI syndrome: improvers and non-improvers. Both groups recover in a different manner postoperatively. Preoperative pain and intraoperative arthrosis of the femoral head differed in the non-improvers compared with the improvers. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Short-term functional outcome after fast-track primary total knee arthroplasty: analysis of 623 patients.

Background and purpose - Early functional outcome after total knee arthroplasty (TKA) has been described before, but without focus on the presence of certain functional recovery patterns. We investigated patterns of functional recovery during the first 3 months after TKA and determined characteristics for non-responders in functional outcome.Patients and methods - All primary TKA in a fast-track setting with complete patient-reported outcome measures (PROMs) preoperatively, at 6 weeks, and 3 months postoperatively were included. Included PROMs were Oxford Knee Score (OKS), Knee disability and Osteoarthritis Outcome Score Physical Function Short-Form (KOOS-PS), and EuroQol 5 dimensions (EQ-5D) including the self-rated health Visual Analogue Scale (VAS). Patients with improvement on OKS less than the minimal clinically important difference (MCID) were determined as non-responders at that time point. Characteristics between groups of responders and non-responders in functional recovery were tested for differences: we defined 4 groups a priori, based on the responder status at each time point.Results - 623 patients were included. At 6 weeks OKS, KOOS-PS, and EQ-5D self-rated health VAS were statistically significant improved compared with preoperative scores. The mean improvement was clinically relevant at 6 weeks for KOOS-PS and at 3 months for OKS. Patient characteristics in non-responders were higher BMI and worse scores on EQ-5D items: mobility, self-care, usual activities, and anxiety/depression.Interpretation - Both statistically significant and clinically relevant functional improvement were found in most patients during the first 3 months after primary TKA. Presumed modifiable patient characteristics in non-responders on early functional outcome were BMI and anxiety/depression.

A radiostereometric and clinical long-term follow-up study of the surface replacement trapeziometacarpal joint prosthesis.

BACKGROUND: The aim of this study was to determine long-term survival and clinical outcomes of the surface replacement trapeziometacarpal joint prosthesis (SR™TMC) and to evaluate implant migration using radiostereometric analysis (RSA). METHODS: In this clinical long-term follow-up study outcomes of ten patients who received the SR™TMC joint prosthesis were evaluated using DASH and Nelson scores, Visual Analogue Scale (VAS) of pain, and key pinch strength. RSA-radiographs were obtained direct postoperatively and 6 months, 1, 5 and 10 years postoperatively and were analyzed using model-based RSA software. RESULTS: During follow-up, two early revisions took place. Mean pre-operative DASH and Nelson scores were 54 (SD 15) and 54 (SD 17), improved significantly after 6 months (DASH 25 (SD 20), Nelson 75 (SD 18)) and remained excellent during long-term follow-up in all patients with a stable implant. At final follow-up, clinical scores deteriorated clearly in two patients with a loose implant in situ. CONCLUSIONS: Long-term survival of the SR™TMC joint prosthesis is relatively poor. However, clinical outcomes improved significantly in the short-term and remained excellent in the long-term in those patients with a stable implant, but deteriorated clearly in case of loosening. The role of RSA in TMC joint arthroplasty is potentially valuable but needs to be further investigated. Several challenges of RSA in the TMC joint have been addressed by the authors and suggestions to optimize RSA-data are given. TRIAL REGISTRATION: This study was registered in the Netherlands Trial Register ( NL7126 ).

Safe Upper Limits of Serum Cobalt and Chromium Levels for a Metal-on-Metal Total Hip Bearing: A 10-Year Follow-Up Study.

BACKGROUND: Long-term survival of metal-on-metal (MoM) prostheses and the development of adverse reaction to metal debris (ARMD) around these bearings are still unclear. Serum levels of cobalt (Co) and chromium (Cr) are used as a screening tool to anticipate failure in MoM bearings and detect ARMD. METHODS: One hundred sixty primary large head MoM prostheses were followed up for 10 years. To estimate the revision risk, the cumulative incidence function (CIF) was used. Subdistribution hazard modeling was used to investigate the associations between cumulative incidence of revision for ARMD and Co levels, Cr levels, gender, age, head size, and cup inclination. Furthermore, the safe upper limits (SULs) for Co and Cr were determined. RESULTS: Univariate analyses showed an increased risk in revision for ARMD in females (subdistribution hazard ratio [sdHR] 3.43, 95% confidence interval [CI] 1.01-11.7, P = .049) and cup inclination angles over 45° (sdHR 4.70, 95% CI 1.63-13.58, P = .004). In addition, a higher last measured Co level (sdHR 1.05, 95% CI 1.03-1.07, P < .001) and last measured Cr level (sdHR 1.21, 95% CI 1.14-1.29, P < .001) were associated with a higher probability of revision for ARMD. We determined our bearing-specific SULs at 4.1 parts per billion (ppb) and 4.2 ppb for Co and Cr, respectively. CONCLUSION: Guidelines regarding follow-up and surveillance should include a complete clinical assessment with bearing-specific SULs of serum metal ion levels. For the M2a-Magnum MoM bearing we advise an SUL for Co and Cr levels of 4.1 and 4.2 ppb, respectively.

Three distinct recovery patterns following primary total knee arthroplasty: dutch arthroplasty register study of 809 patients.

PURPOSE: Total knee arthroplasty (TKA) is usually effective, although not all patients have satisfactory outcomes. This assumes distinct recovery patterns might exist. Little attention has been paid to determine which patients have worse outcomes. This study attempts to distinguish specific recovery patterns using the Oxford knee score (OKS) during the first postoperative year. The secondary aim was to explore predictors of less favourable recovery patterns. METHODS: Analysis of patients in the Dutch Arthroplasty Register (LROI) with unilateral primary TKA. Data collected up to one year postoperative was used. To identify subgroups of patients based on OKS, latent class growth modeling (LCGM) was used. Moreover, multivariable multinomial logistic regression analysis was used to explore predictors of class membership. RESULTS: 809 Patients completed three OKS during the first year postoperative and were included. LCGM identified 3 groups of patients; 'high risers' (most improvement during first 6-months, good 12-month scores 77%), 'gradual progressors' (continuous improvement during the first year 13%) and 'non responders' (initial improvement and subsequent deterioration to baseline score 10%). Predictors of least favourable class membership (OR, 95%CI) are EQ-5D items: VAS health score (0.83, 0.73-0.95), selfcare (2.22, 1.09-4.54) and anxiety/depression (2.45, 1.33-4.52). CONCLUSION: Three recovery patterns after TKA were distinguished; 'high risers', 'gradual progressors' and 'non responders'. Worse score on EQ-5D items VAS health, selfcare, and anxiety/depression were correlated with the least favourable 'non responders' recovery pattern.

Validation of the Dutch version of the Hip Outcome Score; validity, reliability, and responsiveness in patients with femoroacetabular impingement syndrome.

Due to a lack of a validated Dutch version of the Hip Outcome Score (HOS) considering functional outcome after hip arthroscopy for femoroacetabular impingement syndrome, we validated the Dutch version of the HOS (HOS-NL) in patients with femoroacetabular impingement syndrome for reliability, internal consistency, construct- and content validity. Furthermore, the smallest detectable change (SDC) and minimal clinically important difference (MCID) were determined. All consecutive patients scheduled for an arthroscopic procedure for FAIS were selected. Five questionnaires covering groin and hip pain were filled in at three moments in time (two pre-operatively with a maximum two-week interval and 6 months postoperatively). Main endpoints were reliability (test re-test, SDC), internal consistency (Cronbach alpha), construct validity (construct validity was considered sufficient if a least 75% of a-priori made hypotheses were confirmed), content validity (floor and ceiling effects) and responsiveness (MCID). The intraclass correlation coefficient (ICC) was 0.86 for the HOS ADL-NL and 0.81 for the HOS Sports-NL. SDC for the HOS ADL-NL was 21 and for the HOS Sports-NL 29 Cronbach alpha score was 0.882 for HOS ADL-NL and 0.792 for HOS Sports-NL. Construct validity was considered sufficient since 91% of the hypotheses were confirmed. No floor effects were determined. A small ceiling effect was determined for the HOS AD-NL postoperatively. The MCID for HOS ADL-NL and HOS Sports-NL were 14 and 11.0, respectively. The HOS-NL is a reliable and valid patient reported outcome measure for measuring physical function and outcome in active and young patients with femoroacetabular impingement syndrome.