Diagnostic sensitivity and specificity of dynamic three-dimensional CT analysis in detection of cam and pincer type femoroacetabular impingement.

BACKGROUND: Cam and pincer-type morphologies can cause femoroacetabular impingement syndrome (FAI) and can be measured on plain radiographs using the alpha angle and the center edge angle. As an addition to plain radiographs and to assess femoroacetabular impingement, it is possible to visualize the interplay of the acetabular and femoral morphology by means of dynamic three-dimensional simulation of hip joint. Therefore, the objective of this study is to compare alpha angles and center edge angles on plain radiographs with the dynamic computerized tomography (CT) analysis in patients with complaints of femoroacetabular impingement. METHODS: All patients from our prospective cohort from 2012 to 2015 who underwent radiographs and a dynamic CT analysis for FAI were selected. Cam type morphologies were measured with the alpha angle and pincer type morphologies with lateral center-edge angle on radiographs and with CT analysis. The dynamic CT analysis also calculated position and size of impingement of femur and acetabulum. Intra-operative assessment was used to confirm impingement. Sensitivity, specificity and predictive values were calculated compared with respect to the intra-operative assessment. RESULTS: A total of 127 patients were included. 90 cam morphologies and 45 pincer morphologies were identified intra-operatively. The sensitivity and specificity for cam morphology measured with radiographs was 84 and 72% compared to 90 and 43% with three dimensional dynamic analyses. The sensitivity and specificity for pincer morphology measured with radiographs was 82 and 39% compared to 84 and 51% with three dimensional dynamic analyses. CONCLUSIONS: Diagnostic accuracy is comparable in three-dimensional dynamic analysis of CT scans and radiographs representing FAI caused by cam or pincer type morphology. LEVEL OF EVIDENCE: IV.

Developing a risk prediction model for the functional outcome after hip arthroscopy.

BACKGROUND: Hip arthroscopic treatment is not equally beneficial for every patient undergoing this procedure. Therefore, the purpose of this study was to develop a clinical prediction model for functional outcome after surgery based on preoperative factors. METHODS: Prospective data was collected on a cohort of 205 patients having undergone hip arthroscopy between 2011 and 2015. Demographic and clinical variables and patient reported outcome (PRO) scores were collected, and considered as potential predictors. Successful outcome was defined as either a Hip Outcome Score (HOS)-ADL score of over 80% or improvement of 23%, defined by the minimal clinical important difference, 1 year after surgery. The prediction model was developed using backward logistic regression. Regression coefficients were converted into an easy to use prediction rule. RESULTS: The analysis included 203 patients, of which 74% had a successful outcome. Female gender (OR: 0.37 (95% CI 0.17-0.83); p = 0.02), pincer impingement (OR: 0.47 (95% CI 0.21-1.09); p = 0.08), labral tear (OR: 0.46 (95% CI 0.20-1.06); p = 0.07), HOS-ADL score (IQR OR: 2.01 (95% CI 0.99-4.08); p = 0.05), WHOQOL physical (IQR OR: 0.43 (95% CI 0.22-0.87); p = 0.02) and WHOQOL psychological (IQR OR: 2.40 (95% CI 1.38-4.18); p = < 0.01) were factors in the final prediction model of successful functional outcome 1 year after hip arthroscopy. The model's discriminating accuracy turned out to be fair, as 71% (95% CI: 64-80%) of the patients were classified correctly. CONCLUSIONS: The developed prediction model can predict the functional outcome of patients that are considered for a hip arthroscopic intervention, containing six easy accessible preoperative risk factors. The model can be further improved trough external validation and/or adding additional potential predictors.

A quantitative non-invasive assessment of femoroacetabular impingement with CT-based dynamic simulation--cadaveric validation study.

BACKGROUND: Femoroacetabular impingement (FAI) is caused by an anatomic deviation of the acetabular rim or proximal femur, which causes chronic groin pain. Radiological identification of FAI can be challenging. Advances in imaging techniques with the use of computed tomography (CT) scan enable 3D simulation of FAI. We made an experimental cadaveric validation study to validate the 3D simulation imaging software. METHODS: The range of motion (ROM) of five cadaveric hips was measured using an electromagnetic tracking system (EMTS). Specific marked spots in the femur and pelvis were created as reproducible EMTS registration points. Reproducible motions were measured. Hips were subsequently imaged using high-resolution CT after introduction of artificial cam deformities. A proprietary software tool was used, Articulis (Clinical Graphics) to simulate the ROM during the presence and absence of the induced cam deformities. RESULTS: According to the EMTS, 13 of the 30 measured ROM end-points were restricted by > 5° due to the induced cam deformities. Using Articulis, with the same 5° threshold, we correctly detected 12 of these 13 end point limitations and detected no false positives. The median error of the measured limitations was 1.9° (interquartile range 1.1° - 4.4°). The maximum absolute error was 5.4°. CONCLUSIONS: The use of this dynamic simulation software to determine the presence of motion limiting deformities of the femoroacetabular is validated. The simulation software is able to non-invasively detect a reduction in achievable ROM, caused by a cam type deformity.

External validation of the discharge of hip fracture patients score.

PURPOSE: This paper reports the external validation of a recently developed instrument, the Discharge of Hip fracture Patients score (DHP) that predicts discharge location on admission in patients living in their own home prior to hip fracture surgery. METHODS: The DHP (maximum score 100 points) was applied to 125 hip fracture patients aged 50 or more years admitted to an academic centre in the northern part of The Netherlands (Groningen cohort). The characteristics of this cohort, sensitivity, specificity and positive and negative predictive value (PPV, NPV) of the DHP for discharge to an alternative location (DAL) were calculated and compared with the original cohort of hip fracture patients from the western part of The Netherlands (Delft cohort). Scoring 30 points or higher indicated DAL. RESULTS: The Groningen cohort was younger compared to the Delft cohort, (mean age 75.4 vs. 78.5 years, P = 0.005) but was more often classified ASA III/IV (46.4% vs. 25.2%, P < 0.001). Sensitivity of the DHP for DAL in the Groningen cohort was 75% (vs. 83.8%), specificity of 66.7% (vs. 64.7%) and a PPV of 86.3% (vs. 79.2%), compared to the Delft cohort. CONCLUSION: External validation of the DHP was successful; it predicted discharge location of hip fracture patients accurately in another Dutch cohort, the sensitivity for DAL was somewhat lower but the PPV higher. Therefore, the DHP score is a useful valid and easily applied instrument for general hip fracture populations.

Early conversion to below-elbow cast for non-reduced diaphyseal both-bone forearm fractures in children is safe: preliminary results of a multicentre randomised controlled trial.

INTRODUCTION: This multicentre randomised controlled trial was designed to explore whether 6 weeks above-elbow cast (AEC) or 3 weeks AEC followed by 3 weeks below-elbow cast (BEC) cause similar limitation of pronation and supination in non-reduced diaphyseal both-bone forearm fractures in children. MATERIALS AND METHODS: Children were randomly allocated to 6 weeks AEC or to 3 weeks AEC followed by 3 weeks BEC. The primary outcome was limitation of pronation and supination after 6 months. The secondary outcomes were re-displacement of the fracture, complication rate, limitation of flexion and extension of wrist and elbow, cast comfort, cosmetics, complaints in daily life and assessment of radiographs. RESULTS: A group of 23 children was treated with 6 weeks AEC and 24 children with 3 weeks AEC and 3 weeks BEC. The follow-up rate was 98 % with a mean follow-up of 7.0 months. The mean limitation of pronation and supination was 23.3 ± 22.0 for children treated with AEC and 18.0 ± 16.9 for children treated with AEC and BEC. The other study outcomes were similar in both groups. CONCLUSIONS: Early conversion to BEC is safe in the treatment of non-reduced diaphyseal both-bone forearm fractures in children. LEVEL OF EVIDENCE: Multicentre randomised controlled trial, Level II.

Conversion to below-elbow cast after 3 weeks is safe for diaphyseal both-bone forearm fractures in children.

BACKGROUND: It is unclear whether it is safe to convert above-elbow cast (AEC) to below-elbow cast (BEC) in a child who has sustained a displaced diaphyseal both-bone forearm fracture that is stable after reduction. In this multicenter study, we wanted to answer the question: does early conversion to BEC cause similar forearm rotation to that after treatment with AEC alone? CHILDREN AND METHODS: Children were randomly allocated to 6 weeks of AEC, or 3 weeks of AEC followed by 3 weeks of BEC. The primary outcome was limitation of pronation/supination after 6 months. The secondary outcomes were re-displacement of the fracture, limitation of flexion/extension of the wrist and elbow, complication rate, cast comfort, complaints in daily life, and cosmetics of the fractured arm. RESULTS: 62 children were treated with 6 weeks of AEC, and 65 children were treated with 3 weeks of AEC plus 3 weeks of BEC. The follow-up rate was 60/62 and 64/65, respectively with a mean time of 6.9 (4.7-13) months. The limitation of pronation/supination was similar in both groups (18 degrees for the AEC group and 11 degrees for the AEC/BEC group). The secondary outcomes were similar in both groups, with the exception of cast comfort, which was in favor of the AEC/BEC group. INTERPRETATION: Early conversion to BEC cast is safe and results in greater cast comfort.

Impregnation of bone chips with alendronate and cefazolin, combined with demineralized bone matrix: a bone chamber study in goats.

BACKGROUND: Bone grafts from bone banks might be mixed with bisphosphonates to inhibit the osteoclastic response. This inhibition prevents the osteoclasts to resorb the allograft bone before new bone has been formed by the osteoblasts, which might prevent instability. Since bisphosphonates may not only inhibit osteoclasts, but also osteoblasts and thus bone formation, we studied different bisphosphonate concentrations combined with allograft bone. We investigated whether locally applied alendronate has an optimum dose with respect to bone resorption and formation. Further, we questioned whether the addition of demineralized bone matrix (DBM), would stimulate bone formation. Finally, we studied the effect of high levels of antibiotics on bone allograft healing, since mixing allograft bone with antibiotics might reduce the infection risk. METHODS: 25 goats received eight bone conduction chambers in the cortical bone of the proximal medial tibia. Five concentrations of alendronate (0, 0.5 mg/mL, 1 mg/mL, 2 mg/mL, and 10 mg/mL) were tested in combination with allograft bone and supplemented with cefazolin (200 µg/mL). Allograft not supplemented with alendronate and cefazolin served as control. In addition, allograft mixed with demineralized bone matrix, with and without alendronate, was tested. After 12 weeks, graft bone area and new bone area were determined with manual point counting. RESULTS: Graft resorption decreased significantly (p < 0.001) with increasing alendronate concentration. The area of new bone in the 1 mg/mL alendronate group was significantly (p = 0.002) higher when compared to the 10 mg/mL group. No differences could be observed between the group without alendronate, but with demineralized bone, and the control groups. CONCLUSIONS: A dose-response relationship for local application of alendronate has been shown in this study. Most new bone was present at 1 mg/mL alendronate. Local application of cefazolin had no effect on bone remodelling.

Risk factors for failure to return to the pre-fracture place of residence after hip fracture: a prospective longitudinal study of 444 patients.

INTRODUCTION: Long-term place of residence after hip fracture is not often described in literature. The goal of this study was to identify risk factors, known at admission, for failure to return to the pre-fracture place of residence of hip fracture patients in the first year after a hip fracture. METHODS: This is a prospective longitudinal study of 444 consecutive admissions of hip fracture patients aged ≥ 65 years. Place of residence prior to admission, at discharge, after 3 and 12 months was registered. Patients admitted from a nursing home (n = 49) were excluded from statistical analysis. Multivariable logistic regression analysis was performed, using age, gender, presence of a partner, ASA-score, dementia, anaemia at admission, type of fracture, pre-fracture level of mobility and level of activities of daily living (ADL) as possible risk factors. RESULTS: Two hundred eighty-nine patients lived in their own home, 31.8% returned at discharge, 72.9% at 3 months and 72.8% at 12 months. Age, absence of a partner, dementia, and a lower pre-fracture level of ADL or mobility were independent contributors to failure to return to their own home at discharge, 3 or 12 months. 106 patients lived in a residential home; 33.3% returned at discharge, 68.4% at 3 months and 64.4% at 12 months. Age was an independent contributor to failure to return to a residential home. CONCLUSIONS: Age, dementia and a lower pre-fracture level of ADL were the main significant risk factors for failure to return to the pre-fracture residence. As the 3- and 12-month return-rates were similar, 3-month follow-up might be used as an endpoint in future research.

Contralateral hip fractures and other osteoporosis-related fractures in hip fracture patients: incidence and risk factors. An observational cohort study of 1,229 patients.

PURPOSE: To report risk factors, 1-year and overall risk for a contralateral hip and other osteoporosis-related fractures in a hip fracture population. METHODS: An observational study on 1,229 consecutive patients of 50 years and older, who sustained a hip fracture between January 2005 and June 2009. Fractures were scored retrospectively for 2005-2008 and prospectively for 2008-2009. Rates of a contralateral hip and other osteoporosis-related fractures were compared between patients with and without a history of a fracture. Previous fractures, gender, age and ASA classification were analysed as possible risk factors. RESULTS: The absolute risk for a contralateral hip fracture was 13.8 %, for one or more osteoporosis-related fracture(s) 28.6 %. First-, second- and third-year risk for a second hip fracture was 2, 1 and 0 %. Median (IQR) interval between both hip fractures was 18.5 (26.6) months. One-year incidence of other fractures was 6 %. Only age was a risk factor for a contralateral hip fracture, hazard ratio (HR) 1.02 (1.006-1.042, p = 0.008). Patients with a history of a fracture (33.1 %) did not have a higher incidence of fractures during follow-up (16.7 %) than patients without fractures in their history (14 %). HR for a contralateral hip fracture for the fracture versus the non-fracture group was 1.29 (0.75-2.23, p = 0.360). CONCLUSION: The absolute risk of a contralateral hip fracture after a hip fracture is 13.8 %, the 1-year risk was 2 %, with a short interval between the 2 hip fractures. Age was a risk factor for sustaining a contralateral hip fracture; a fracture in history was not.

Outcome in hip fracture patients related to anemia at admission and allogeneic blood transfusion: an analysis of 1262 surgically treated patients.

BACKGROUND: Anemia is more often seen in older patients. As the mean age of hip fracture patients is rising, anemia is common in this population. Allogeneic blood transfusion (ABT) and anemia have been pointed out as possible risk factors for poorer outcome in hip fracture patients. METHODS: In the timeframe 2005-2010, 1262 admissions for surgical treatment of a hip fracture in patients aged 65 years and older were recorded. Registration was prospective from 2008 on. Anemic and non-anemic patients (based on hemoglobin level at admission) were compared regarding clinical characteristics, mortality, delirium incidence, LOS, discharge to a nursing home and the 90-day readmission rate. Receiving an ABT, age, gender, ASA classification, type of fracture and anesthesia were used as possible confounders in multivariable regression analysis. RESULTS: The prevalence of anemia and the rate of ABT both were 42.5%. Anemic patients were more likely to be older and men and had more often a trochanteric fracture, a higher ASA score and received more often an ABT. In univariate analysis, the 3- and 12-month mortality rate, delirium incidence and discharge to a nursing home rate were significantly worse in preoperatively anemic patients.In multivariable regression analysis, anemia at admission was a significant risk factor for discharge to a nursing home and readmission < 90 days, but not for mortality. Indication for ABT, age and ASA classification were independent risk factors for mortality at all moments, only the mortality rate for the 3-12 month interval was not influenced by ABT. An indication for an ABT was the largest negative contributor to a longer LOS (OR 2.26, 95% CI 1.73-2.94) and the second largest for delirium (OR 1.67, 95% CI 1.28-2.20). CONCLUSIONS: This study has demonstrated that anemia at admission and postoperative anemia needing an ABT (PANT) were independent risk factors for worse outcome in hip fracture patients. In multivariable regression analysis, anemia as such had no effect on mortality, due to a rescue effect of PANT. In-hospital, 3- and 12-month mortality was negatively affected by PANT, with the main effect in the first 3 months postoperatively.

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.

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.

Citation analysis of orthopaedic literature; 18 major orthopaedic journals compared for Impact Factor and SCImago.

BACKGROUND: One of the disadvantages of the Impact Factor (IF) is self-citation. The SCImago Journal Rank (SJR) indicator excludes self-citations and considers the quality, rather than absolute numbers, of citations of a journal by other journals. The present study re-evaluated the influence of self-citation on the 2007 IF for 18 major orthopaedic journals and investigated the difference in ranking between IF and SJR. METHODS: The journals were analysed for self-citation both overall and divided into a general group (n = 8) and a specialized group (n = 10). Self-cited and self-citing rates, as well as citation densities and IFs corrected for self-citation (cIF), were calculated. The rankings of the 18 journals by IF and by SJR were compared and the absolute difference between these rankings (DeltaR) was determined. RESULTS: Specialized journals had higher self-citing rates (p = 0.01, Deltamedian = 9.50, 95%CI -19.42 to 0.42), higher self-cited rates (p = 0.0004, Deltamedian = -10.50, 95%CI -15.28 to -5.72) and greater differences between IF and cIF (p = 0.003, Deltamedian = 3.50, 95%CI -6.1 to 13.1). There was no significant correlation between self-citing rate and IF for both groups (general: r = 0.46, p = 0.27; specialized: r = 0.21, p = 0.56). When the difference in ranking between IF and SJR was compared between both groups, sub-specialist journals were ranked lower compared to their general counterparts (DeltaR: p = 0.006, Deltamedian = 2.0, 95%CI -0.39 to 4.39). CONCLUSIONS: Citation analysis shows that specialized orthopaedic journals have specific self-citation tendencies. The correlation between self-cited rate and IF in our sample was large but, due to small sample size, not significant. The SJR excludes self-citations in its calculation and therefore enhances the underestimation in ranking of specialized journals.

Impregnation of bone chips with antibiotics and storage of antibiotics at different temperatures: an in vitro study.

BACKGROUND: Allograft bone used in joint replacement surgery can additionally serve as a carrier for antibiotics and serve as a prophylaxis against infections. However, in vitro dose-response curves for bone chips impregnated with different kinds of antibiotics are not available. In addition, while it would be desirable to add the antibiotics to allograft bone chips before these are stored in a bone bank, the effects of different storage temperatures on antibiotics are unknown. METHODS: Five different antibiotics (cefazolin, clindamycin, linezolid, oxacillin, vancomycin) were stored, both as pills and as solutions, at -80 degrees C, -20 degrees C, 4 degrees C, 20 degrees C and 37 degrees C; in addition, bone chips impregnated with cefazolin and vancomycin were stored at -80 degrees C and -20 degrees C. After 1 month, 6 months and 1 year, the activity of the antibiotics against Staphylococcus epidermidis was measured using an inoculated agar. The diameter of the S. epidermidis-free zone was taken as a measure of antibiotic activity. In a separate experiment, in vitro dose-response curves were established for bone chips impregnated with cefazolin and vancomycin solutions at five different concentrations. Finally, the maximum absorbed amounts of cefazolin and vancomycin were established by impregnating 1 g of bone chips with 5 ml of antibiotic solution. RESULTS: A decrease of the S. epidermidis-free zone was seen with oxacillin and cefazolin solutions stored at 37 degrees C for 1 month, with vancomycin stored at 37 degrees C for 6 months and with cefazolin and oxacillin solutions stored at 20 degrees C for 6 months. The activity of the other antibiotic solutions, pills and impregnated bone chips was not affected by storage. The in vitro dose-response curves show that the free-zone diameter increases logarithmically with antibiotic concentration. The absorbed antibiotic amount of one gram bone chips was determined. CONCLUSIONS: Storage of antibiotics in frozen form or storage of antibiotic pills at temperatures up to 37 degrees C for 12 months does not affect their activity. However, storage of antibiotic solutions at temperatures above 20 degrees C does affect the activity of some of the antibiotics investigated. The in vitro dose-response curve can be used to determine the optimal concentration(s) for local application. It provides the opportunity to determine the antibiotic content of bone chips, and thus the amount of antibiotics available locally after application.

Traction force for peroperative hip dislocation in hip arthroscopy.

OBJECTIVES: Traction force widens the joint space during hip arthroscopy. It is unclear how much the traction force varies and if it is related to the joint space widening. Main goal of our study was to measure the amount of force needed to widen the hip joint. Second goal was to study the relation between this force and the amount of joint space widening. METHODS: Traction force was measured in 27 patients (of whom 24 female, mean age 41) during arthroscopy. Measurements were performed before the procedure, after vacuum seal release and after capsulotomy. Joint space widening was measured with fluoroscopy and was calibrated. Friedman and Wilcoxon tests were used to measure differences in traction. The Spearman's rho correlation coefficient was used to identify a correlation in traction force and joint space widening. Regression analyses were used to identify relations between age, body mass index (BMI), hip degeneration and traction force. RESULTS: The median traction force before arthroscopy was 714 N, lowered to 520 N after vacuum seal release and to 473 N after capsulotomy (p < 0.001). Median joint space widening was 8.8 mm. Spearmans' rho correlation between traction force and joint space widening was ‒0.13. DISCUSSION: Median traction force of 714 N resulted in 8.8 mm of joint space widening. This traction force was significantly lowered by 200 N after release of the vacuum seal of the hip and 250 N after additional capsulotomy without loss of joint space narrowing. No significant relation was identified for age, BMI or progression of the Kellgren-Lawrence classification for hip degeneration and traction force. Netherlands Trial Registry number 8610.

Only MR can safely exclude patients from arthroscopy.

OBJECTIVE: The aim of this study was to determine in patients with subacute knee complaints and normal standardized physical examination the fraction of magnetic resonance imaging (MRI) studies showing arthroscopically treatable intra-articular pathology. MATERIAL AND METHODS: There were 290 consecutive patients (between 16 and 45 years) with at least 4 weeks of knee complaints and low clinical suspicion of intra-articular pathology based on physical exam. Two hundred seventy-four patients were included. Sixteen patients with prior knee surgery, rheumatic arthritis, or severe osteoarthritis were excluded. MRI was used to assign patients to group 1 (treatable abnormalities) or group 2 (normal or no treatable findings), depending on whether MR demonstrated treatable pathology. Arthroscopy was performed in group 1 patients. If symptoms persisted for 3 months in group 2 patients, cross over to arthroscopy was allowed. RESULTS: MR showed treatable pathology in 73 patients (26.6%). Arthroscopy was performed in 64 patients of 73 patients (group 1). In 52 patients (81.3%, 95% confidence interval (CI) 71.4-91.1%), arthroscopy was therapeutic. Of the 13 arthroscopies (6.5%) in group 2, four were therapeutic (30.8%, 95% CI 1.7-59.8). The highest fraction of MR studies showing treatable pathology was found in males, aged over 30 years, with a history of effusion (54.5%, six of 11 patients). CONCLUSION: Authors believe that the negative predictive value of clinical assessment in patients with subacute knee complaints is too low to exclude these patients from MR. MR should at least be considered in male patients aged 30 years and over with a history of effusion.

Incidence of symptomatic femoroacetabular impingement in the general population: a prospective registration study.

Groin pain is a frequent cause of discomfort in patients and highly prevalent in active patients. One of the diagnoses causing groin pain is femoroacetabular impingement (FAI). However, the incidence of FAI in the general population is unknown. This study aimed to identify the incidence of groin pain suggestive of FAI in a cohort of 31 451 patients in the Netherlands during 1 year. A cooperation of 16 general practitioners (GPs) participated in this prospective registry. All GPs were educated in the clinical manifestation of FAI and the physical examination for FAI. Patients of all ages were registered when presenting with 'groin pain'. Between July 2013 and July 2014, 84 patients aged between 15 and 60 years of age presented with groin pain, reflecting an incidence of 0.44%. Of these patients, 17% (14 patients) were radiologically diagnosed with FAI. Another 30% of these patients had a high clinical suspicion for FAI. This is the first report on the incidence of groin pain suggestive of FAI in a general population diagnosed by GPs. Of all 84 patients presenting with groin pain, 17% were diagnosed with FAI. Creating awareness of FAI in GPs helps identifying patients that might benefit from FAI treatment.

The Effect of Door Openings on Numbers of Colony Forming Units in the Operating Room during Hip Revision Surgery.

BACKGROUND: The aim of this study was to investigate the effect of door opening rates on air quality in the operation room during hip revision surgery by measuring the number of colony forming units per cubic meter (CFU/m(3)). METHODS: During 70 hip revision operations the number of CFU/m(3) was measured at four time points. Factors that may influence air quality were recorded, including the number of persons present, duration of surgery, and door opening rates. The measured CFU/m(3) was dichotomized as either acceptable (≤20 CFU/m(3)) or not acceptable (>20 CFU/m(3)). To determine whether door openings were associated with CFU/m(3) values, we used generalized linear mixed models to model the dichotomized repeatedly measured CFU/m(3) values. RESULTS: The median number of door openings per operation was eight (range, 0-72), the median duration of surgery was 145 min (range, 60-285), and the median number of persons present during surgery was eight (range, 5-10). Adjusted for number of persons in the operation room and duration of surgery, the number of door openings per operation was associated (odds ratio [OR] 1.05 [95% confidence interval {CI} 1.02-1.09]; p = 0.003) with an unacceptable number of CFU/m(3). CONCLUSIONS: In conclusion, a substantial association between number of door openings and an unacceptable number (>20) of CFU/m(3) was found. Adjusted for number of persons in the operation room and duration of surgery, every door opening increased the odds of unacceptable CFU/m(3) values by 5%. Number of persons present during surgery and duration of surgery were not related to CFU/m(3).

Which factors affect limitation of pronation/supination after forearm fractures in children? A prospective multicentre study.

INTRODUCTION: Both-bone forearm fractures in children frequently result in a limitation of pronation/supination, which hinders daily activities. The purpose of this prospective multicentre study was to investigate which clinical factors are related to the limitation of pronation/supination in children with a both-bone forearm fracture. METHODS: In four Dutch hospitals, consecutive children (<16 years) who sustained a both-bone forearm fracture were included. Children were followed up for 6-9 months and data from questionnaires, physical examination and X-rays were collected. Univariate and multivariate logistic regression analyses were used to assess the relationship between limitation of pronation/supination (≥20°) and several clinical factors. RESULTS: A group of 410 children with both-bone forearm fractures were included, of which 10 children missed the final examination (follow-up rate of 97.6%). We found that a re-fracture (odds ratio (OR) 11.7, 95% confidence interval (CI) 1.2; 118.5), a fracture in the diaphysis (OR 3.3, 95% CI 1.4; 7.9) and less physiotherapy during follow-up (OR 0.90, 95% CI 0.82; 0.98) were independently associated with a limitation of pronation/supination of 20° or more. CONCLUSIONS: These findings imply that a re-fracture and a diaphyseal located fracture were associated independently of each other with a limitation of pronation/supination in children with a both-bone forearm fracture. Furthermore, in children with severe limitation extensive physiotherapy is associated with better functional outcome.

More than half of hip fracture patients do not regain mobility in the first postoperative year.

AIM: To measure functional recovery and determine risk factors for failure to return to the prefracture level of mobility of hip fracture patients 1 year postoperatively. METHODS: A prospective cohort follow-up study of 390 hip fracture patients aged 65 years and older was carried out. Patients were stratified in categories based on prefracture mobility: mobile without aid, with aid in- and outdoors, or only mobile indoors. Immobile patients were excluded. Risk factors for not regaining prefracture mobility were identified. RESULTS: Nearly half of all patients regained their prefracture level of mobility after 1 year. Mobile patients without an aid were less likely to return to their prefracture mobility level compared with patients who were mobile with aid or mobile indoors. After 1 year, 18.7% of all patients had become immobile. Most important independent risk factors for failure to return to the prefracture level of mobility were a limited prefracture level of activities of daily living and a delirium during admission. CONCLUSIONS: The risk not to regain prefracture mobility is highest in mobile patients without an aid. The risk of becoming immobile is higher in those having a lower prefracture mobility. Activities of daily living dependence and delirium were the main risk factors for not regaining mobility.