Hip dysplasia as risk factor for clinically relevant and radiographic hip osteoarthritis: 10-year results from the CHECK cohort.

OBJECTIVES: To investigate hip dysplasia as a risk factor for clinically relevant and incident radiographic hip osteoarthritis. METHODS: From a prospective cohort (CHECK) of 1002 middle-aged, new consulters for hip and/or knee pain, 468 hips (251 individuals) were selected based on hip pain, available lateral center edge angle (LCEA) and absence of definite radiographic hip OA (Kellgren and Lawrence grade (KL) <2) at baseline, as well as available follow-up measures. Clinically relevant hip OA was defined by an expert diagnosis based on clinical and radiographic data obtained between year 5-10 from baseline. Incident radiographic hip OA was defined by KL grade ≥2 or a total hip replacement at the 10-year follow-up. Associations between hip dysplasia (LCEA ≤20°) and outcomes were expressed in odds ratios (OR) adjusted for age, sex and BMI. RESULTS: At baseline, participants had a mean age of 55.5 years (SD 5.4), 88% were female and, on hip level, the prevalence of hip dysplasia was 3.6% (n = 17). After 10 years, hip dysplasia was associated with an increased risk for clinically relevant hip OA (OR 2.80 (95% CI 1.15, 6.79), but not for incident radiographic hip OA (OR 0.78 (95% CI 0.26, 2.30)). CONCLUSION: In the long term, baseline hip dysplasia was associated with an increased risk for clinically relevant hip OA, but not for incident radiographic hip OA. With this in mind, we suggest that future research investigating the link between hip dysplasia and OA strive to include a definition for OA that is clinically relevant.

6 compared with 12 weeks treatment in the von Rosen splint is sufficient for Barlow and Ortolani positive hips: a comparative study of 237 neonates.

BACKGROUND AND PURPOSE: At our institution, newborns with Barlow or Ortolani positive hips have been treated for 12 weeks with the von Rosen abduction splint until 2012 when the treatment length was halved. We investigate whether acetabular development at 12 months of age and complications differ between hips treated with the von Rosen splint for 6 compared with 12 weeks. PATIENTS AND METHODS: 99 patients were included in the 6-week program and 138 patients in the 12-week program. We measured the acetabular index (AI) on standard anteroposterior pelvic radiographs taken at 12 months of age. Medical records were reviewed for complications and additional treatments until age 12 months. We used non-inferiority testing with an equivalence margin of 1° with a 95% confidence interval (CI) to compare the 2 groups. RESULTS: The mean AI at 12 months in the 6-week group was 25° (CI 24-26) compared with 25° (CI 25-26) in the 12-week group. Non-inferiority was demonstrated for the 6-week program: -0.2° (CI -1.1 to 0.7). In the 6-week group, 8 patients received additional treatment, including 1 hip dislocation that occurred between 6 weeks and 3 months. There were no additional treatments or complications in the 12-week group. CONCLUSION: AI was equal at 12 months of age for patients treated for 6 compared with 12 weeks in the von Rosen splint. The hip dislocation which occurred indicates that follow-up around 3 months of age is indicated.

The International Hip Dysplasia Institute (IHDI) classification is more informative than the Tönnis classification.

BACKGROUND: A new, supposedly more reproducible radiographic classification, set to replace the Tönnis classification of hip dislocations, was proposed in 2015: the International Hip Dysplasia Institute (IHDI) classification. PURPOSE: To compare the IHDI classification with the Tönnis classification when evaluating the severity of hip dislocations as well as their respective inter- and intra-observer reliability. MATERIAL AND METHODS: Since January 2000, Swedish-born children with a hip dislocation were prospectively registered. From this registry, radiographs of 97 hips in 79 patients (91% girls; median age = 7 months), born in 2000-2009, were analyzed. Two observers, one consultant and one resident, classified each hip both by IHDI and Tönnis twice. RESULTS: The IHDI classification had a more even distribution of grades with the majority in grade 2-3. The Tönnis classification graded the majority (77%) of the patients as grade 2 and equally among the other grades. There was moderate inter-observer agreement using both methods calculated with Kappa, 0.61 (95% confidence interval [CI] = 0.44-0.79) for Tönnis and 0.62 (95% CI = 0.49-0.74) for IHDI. The resident calculated Tönnis with weak intra-observer reliability of 0.57 (95% CI = 0.40-0.74) compared to high intra-observer reliability of 0.86 (95% CI = 0.74-0.98) for the consultant. Both observers graded IHDI with high intra-observer reliability. CONCLUSION: IHDI is more discriminative than the Tönnis classification when evaluating the severity of a hip dislocation in infants.

Hip dysplasia is not uncommon but frequently overlooked: a cross-sectional study based on radiographic examination of 1,870 adults.

Background and purpose - Hip dysplasia in adults is a deformity in which the acetabulum inadequately covers the femoral head. The prevalence is sparingly described in the literature. We investigated the prevalence in Malmö (Sweden) and assessed whether the condition was recognized in the radiology reports.Subjects and methods - All pelvic radiographs performed in Malmö during 2007-2008 on subjects aged 20-70 years with a Swedish personal identity number were assessed. 1,870 digital radiographs were eligible for analysis. The lateral center-edge angle (LCEA) and acetabular index angle (AIA) were measured. Hip dysplasia was defined as an LCEA ≤ 20°. Intraclass correlation coefficients (ICC) for intra-observer measurements ranged from 0.87 (AIA, 95% CI 0.78-0.93) to 0.98 (LCEA, CI 0.97-0.99).Results - The prevalence of hip dysplasia (LCEA ≤ 20°) was 5.2% (CI 4.3-6.3), (98/1,870). There was no statistically significant difference between the sexes for either prevalence of hip dysplasia or mean LCEA. The mean AIA was 0.9° (CI 0.3-1.3) higher in men (4.1 SD 5.5) compared with women (3.2 SD 5.4). The radiologists had reported hip dysplasia in 7 of the 98 cases.Interpretation - The prevalence of hip dysplasia in Malmö (Sweden) is similar to previously reported data from Copenhagen (Denmark) and Bergen (Norway). Our results indicate that hip dysplasia is often overlooked by radiologists, which may influence patient treatment.

Estimated effect of secondary screening for hip dislocation.

OBJECTIVES: To quantify the effect of secondary screening for hip dislocations. DESIGN: Retrospective analysis of hospital files from participants in a prospectively collected nationwide registry. SETTING: Child healthcare centres and orthopaedic departments in Sweden. PARTICIPANTS: Of 126 children with hip dislocation diagnosed later than 14 days age in the 2000-2009 birth cohort, 101 had complete data and were included in the study. INTERVENTIONS: The entire birth cohort was subject to clinical screening for hip instability at 6-8 weeks, 6 months and 10-12 months age. Children diagnosed through this screening were compared with children presenting due to symptoms, which was used as a surrogate variable representing a situation without secondary screening. MAIN OUTCOME MEASURES: Age at diagnosis and disease severity of late presenting hip dislocations. RESULTS: Children diagnosed through secondary screening were 11 months younger (median: 47 weeks) compared with those presenting with symptoms (p<0.001). Children diagnosed through secondary screening had 11% risk of having a high (severe) dislocation, compared with 38% for those diagnosed due to symptoms; absolute risk reduction 27% (95% CI: 9.7% to 45%), relative risk 0.28 (95% CI: 0.11 to 0.70). Children presenting due to symptoms had OR 5.1 (95% CI: 1.7 to 15) of having a high dislocation, and OR 11 (95% CI: 4.1 to 31) of presenting at age 1 year or older, compared with the secondary screening group. The secondary screening was able to identify half of the children (55%, 95% CI: 45% to 66%) not diagnosed through primary screening. CONCLUSIONS: Secondary screening at child healthcare centres may have substantially lowered the age at diagnosis in half of all children with late presenting hip dislocation not diagnosed through primary screening, with the risk of having a high dislocation decreased almost to one-quarter in such cases.

Is good muscle function a protective factor for early signs of knee osteoarthritis after anterior cruciate ligament reconstruction? The SHIELD cohort study protocol.

Introduction: Knee injury history and increased joint load, respectively, are major risk factors for the development of knee osteoarthritis (OA). Lower extremity muscle function, such as knee muscle strength, influence joint load and may be important for the onset of knee OA. However, the role of muscle function as a possible modifiable protective mechanism for the development of OA after anterior cruciate ligament reconstruction (ACLR) is not clear. Methods and analysis: In this prospective cohort study, 100 patients (50% women, 18-35 years) with ACLR will be recruited from Skåne University Hospital, Sweden and Oslo University Hospital, Norway. They will be assessed with a comprehensive test battery of muscle function including muscle strength, muscle activation, hop performance, and postural orientation as well as patient-reported outcomes, one year (baseline) and three years (follow-up) after ACLR. Primary predictor will be knee extension strength, primary outcome will be patient-reported knee pain (Knee injury and Osteoarthritis Outcome Score, subscale pain) and secondary outcomes include compositional MRI (T2 mapping) and turnover of cartilage and bone biomarkers. Separate linear regression model will be used to elucidate the influence of each baseline muscle function variable on the outcomes at follow-up, adjusted for baseline values. Twenty non-injured individuals will also be assessed with MRI. This study is approved by The Regional Ethical Review Board in Lund (Sweden) and Oslo (Norway). Discussion: This study may have important clinical implications for using muscle function to screen for risk of early-onset knee OA and for optimizing exercise therapy after knee injury.

Pediatric Distal Forearm Fracture Epidemiology in Malmö, Sweden-Time Trends During Six Decades.

Background The distal forearm fracture is the most common fracture in children. To allocate health care resources and evaluate if prevention strategies have been successful, it is essential to monitor changes in the epidemiology of common fractures. Methods Our hospital serves a city in which year 2006 included 276,244 inhabitants (49,664 <17 years of age). Through the hospital archives, we identified fractures sustained by individuals younger than 16 years during 2005 and 2006 and compared these with previous collected and published data from the same area and hospital for the period 1950 to 1994. We used official population data to estimate period-specific fracture rates and age and gender standardized time trends. We report rates as number of fractures per 100,000 person-years and changes between periods as rate ratios (RR) with 95% confidence intervals (CIs). Results We identified 521 distal forearm fractures, corresponding to a crude fracture incidence of 564/100,000 person-years (boys 719; girls 401). Age-adjusted fracture incidence was 70% higher in boys than in girls (RR 1.7; 95% CI 1.3-2.3). The age- and gender-adjusted hand fracture incidence was 40% higher in 2005-2006 than in 1950/1955 (RR 1.4; 95% CI 1.2 to 1.8) but no higher than 1993-1994 (RR 1.1; 95% CI 0.9-1.3). Fracture etiology of 2005 to 2006 included sports injuries in 41% and traffic accidents in 11% of the cases, while sports injuries explained 37% and traffic accidents 18% in 1950 to 1955. Conclusion In 2005 to 2006, we found higher rates in boys and higher overall rates compared with the 1950s but no significant differences compared with the rates in 1993 to 1994. Future studies should include patient-specific data to unravel causal factors. Level of evidence This is a Level III b study.

Incidence of Late-Diagnosed Hip Dislocation After Universal Clinical Screening in Sweden.

Importance: Developmental dysplasia of the hip, including late-diagnosed hip dislocation, is the leading cause of hip arthroplasties in young adults. Early treatment is essential for a good prognosis. Before the institution of a national screening program, a minimum of 0.9 per 1000 Swedish children were affected. Objectives: To evaluate the incidence of late-diagnosed hip dislocation among children who undergo clinical screening as neonates and to study antenatal and perinatal risk factors for late-diagnosed hip dislocation. Design, Setting, and Participants: This nested case-control study included children born in Sweden from January 1, 2000, through December 31, 2009. All maternity wards, maternal health units, and orthopedic departments in Sweden participated. Children with a late-diagnosed hip dislocation were matched by sex and birth year to randomly selected controls in a 1:10 ratio. Potential risk factors in pregnant women and newborns were recorded, and cases of hip dislocation were registered. Observation time ranged from 8 to 18 years, with the last data analysis in January 2019. Exposures: Clinical hip examinations neonatally and at 6 to 8 weeks, 6 months, and 10 to 12 months. Main Outcomes and Measures: Hip dislocation diagnosed more than 14 days after birth, age at diagnosis, and severity of dislocation. Results: Among 1 013 589 live births (521 728 [51.5%] boys), 126 children (0.12 [95% CI, 0.10-0.15] per 1000 live births) had a late-diagnosed hip dislocation at a median age of 31.4 weeks (interquartile range, 16.1-67.1 weeks; 95% CI, 27.4-44.1 weeks). The incidence of late-diagnosed hip dislocation was 9 times higher among girls (113 of 491 861; 0.23 [95% CI, 0.19-0.28] per 1000 live births) than among boys (13 of 521 728; 0.02 [95% CI, 0.01-0.04] per 1000 live births). Twenty-one children (0.02 per 1000 live births) had high (severe) dislocations. Breech delivery (adjusted odds ratio, 3.07; 95% CI, 1.34-7.02), short body length at birth (adjusted odds ratio, 0.86; 95% CI, 0.76-0.98, per additional 1 cm), and being large for gestational age (adjusted odds ratio, 3.59; 95% CI, 1.30-9.95) were independent risk factors. Maternal smoking at the first visit to the maternal health care center was less common among children with hip dislocation (adjusted odds ratio, 0.16; 95% CI, 0.04-0.70). Conclusions and Relevance: Compared with historical data, the incidence of late-diagnosed hip dislocation in Swedish-born children appears to have decreased substantially since the screening program was initiated, as have the age at detection and disease severity. Similar screening programs should also be possible to institute in upper-middle- and lower-middle-income countries.

Hand fracture epidemiology and etiology in children-time trends in Malmö, Sweden, during six decades.

BACKGROUND: The aim of this study was to describe hand fracture epidemiology/etiology in city children and describe time trend during six decades. PATIENTS AND METHODS: A single hospital serves the entire city population of 271,271 (year 2005). Through the hospital medical and radiological archives, we collected epidemiology and etiology data concerning pediatric (age < 16 years) hand fractures in city residents, treated during 2005-2006. We compared these data to previously collected data in in the same city during 12 evaluated periods from 1950/1955 to 1993-1994. We present period-specific crude and age- and gender-adjusted fracture incidence rates and group differences as incidence rate ratios (RR) with 95% confidence intervals (95% CI). RESULTS: In 2005-2006, we identified 414 hand fractures (303 in boys and 111 in girls), 247 phalangeal fractures (60% of all hand fractures), 140 metacarpal/carpal fractures (except the scaphoid bone) (34%), and 27 scaphoid fractures (6%). The crude hand fracture rate in children was 448/100,000 person years (639/100,000 in boys and 247/100,000 in girls), with a 2.5 times higher age-adjusted incidence in boys than in girls. Compared to 1950/1955, the age and gender-adjusted hand fracture incidence was twice as high in 2005-2006 and more than twice as high in 1976-1979. Compared to 1976-1979, we found no significant difference in the age and gender-adjusted hand fracture incidence in 2005-2006. In 2005-2006, sports injuries explained 42%, fights 20%, and traffic accidents 13% of the hand fractures. In 1950/1955, sports injuries explained 27% of fractures, fights 10%, and traffic accidents 21%. CONCLUSIONS: The incidence of hand fractures in children was more than twice as high in the end of the 1970s compared to the 1950s, where after no significant change could be found. Also, fracture etiology has changed. New studies are needed, to adequately allocate health care resources and identify new fracture prone activities suitable for preventive measures. LEVEL OF EVIDENCE: III.

Pre-contrast T1 and cartilage thickness as confounding factors in dGEMRIC when evaluating human cartilage adaptation to physical activity.

BACKGROUND: The dGEMRIC (delayed Gadolinium-Enhanced MRI of Cartilage) technique has been used in numerous studies for quantitative in vivo evaluation of the relative glycosaminoglycan (GAG) content in cartilage. The purpose of this study was to determine the influence of pre-contrast T1 and cartilage thickness when assessing knee joint cartilage quality with dGEMRIC. METHODS: Cartilage thickness and T1 relaxation time were measured in the central part of the femoral condyles before and two hours after intravenous Gd-DTPA2- administration in 17 healthy volunteers from a previous study divided into two groups: 9 sedentary volunteers and 8 exercising elite runners. Results were analyzed in superficial and a deep weight-bearing, as well as in non-weight-bearing regions of interest. RESULTS: In the medial compartment, the cartilage was thicker in the exercising group, in weight-bearing and non-weight-bearing segments. In most of the segments, the T1 pre-contrast value was longer in the exercising group compared to the sedentary group. Both groups had a longer pre-contrast T1 in the superficial cartilage than in the deep cartilage. In the superficial cartilage, the gadolinium concentration was independent of cartilage thickness. In contrast, there was a linear correlation between the gadolinium concentration and cartilage thickness in the deep cartilage region. CONCLUSION: Cartilage pre-contrast T1 and thickness are sources of error in dGEMRIC that should be considered when analysing bulk values. Our results indicate that differences in cartilage structure due to exercise and weight-bearing may be less pronounced than previously demonstrated.

Delayed gadolinium-enhanced MRI of menisci and cartilage (dGEMRIM/dGEMRIC) in obese patients with knee osteoarthritis: Cross-sectional study of 85 obese patients with intra-articular administered gadolinium contrast.

BACKGROUND: Early cartilage changes in knee osteoarthritis (OA) can be assessed by both intravenous (i.v.) and intra-articular (i.a.) delayed gadolinium-enhanced MRI of cartilage (dGEMRIC). PURPOSE: To examine the relationship between i.a. dGEMRIC and delayed gadolinium-enhanced MRI of menisci (dGEMRIM), and to investigate if the approach can be used to assess the morphological degeneration of menisci in obese patients with knee OA. STUDY TYPE: Cross-sectional. POPULATION: Eighty-five obese patients with knee OA. FIELD STRENGTH/SEQUENCES: 1.5T. Inversion recovery sequence with four inversion times. ASSESSMENT: T1 relaxation times were calculated for posterior weight-bearing femoral cartilage and the posterior horns of the menisci. Meniscus degeneration sum score (0-2) was assessed as increased signal/no signal (1/0) and tear/no tear (1/0). STATISTICAL TESTS: T1 relaxation times were compared using Student's t-test. Comparison of cartilage and meniscus T1 relaxation times was done by regression analysis. Analysis of variance (ANOVA) was used for comparison of meniscal T1 relaxation times among the three summed morphological scores (0-2). Statistical analyses were performed with a level of significance at 0.05. RESULTS: For lateral menisci, morphology sum scores of 0, 1, and 2 were found in 13, 58, and 14 patients and for medial menisci in 2, 30, and 30 patients, respectively. Mean T1 relaxation times were 441 msec, 480 msec, and 497 msec for cartilage, lateral menisci, and medial menisci, respectively. T1 relaxation times for the menisci were similar (P = 0.53), and a weak correlation was found between dGEMRIC and dGEMRIM in the lateral compartments (R = 0.26). Comparing dGEMRIM between different morphology sum scores showed no differences (P > 0.4). DATA CONCLUSION: I.a. dGEMRIM showed no correlation between the degree of meniscal degeneration and meniscus T1 relaxation times. I.a. dGEMRIM do not seem to deliver useful information about meniscus degeneration to be suitable for clinical applications, but i.a. dGEMRIC may still be considered an alternative contrast-saving method for cartilage. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;48:1700-1706.

Poor outcome after a surgically treated chondral injury on the medial femoral condyle: early evaluation with dGEMRIC and 17-year radiographic and clinical follow-up in 16 knees.

Background and purpose - The optimal treatment for traumatic cartilage injuries remains unknown. Contrast-enhanced MRI of cartilage (dGEMRIC) evaluates cartilage quality and a low dGEMRIC index may predict radiographic osteoarthritis (OA). The purpose of this study was (a) to explore the results 17 years after surgical treatment of an isolated cartilage knee injury and (b) to evaluate the predictive value of dGEMRIC. Patients and methods - 16 knees with an isolated traumatic cartilage injury of the medial femoral condyle had cartilage repair surgery either by microfracture or autologous cartilage implantation. dGEMRIC of the injured knee was performed 2 years after surgery and radiographic examinations were performed 17 years after the operation. Results - Radiographic OA was present in 12 of 16 knees. Irrespective of surgical method, the dGEMRIC index was lower in repair tissue compared with adjacent cartilage in the medial compartment, 237 ms vs. 312 ms (p < 0.001), which in turn had lower value than in the non-injured lateral cartilage, 312 ms vs. 354 ms (p < 0.008). The dGEMRIC index in the cartilage adjacent to the repair tissue correlated negatively with radiographic osteophyte score, r = -0.75 (p = 0.03). Interpretation - A traumatic cartilage injury is associated with a high prevalence of OA after 17 years. The low dGEMRIC index in the repair tissue 2 years postoperatively indicates fibrocartilage of low quality. The negative correlation between the dGEMRIC index in the adjacent cartilage and future OA suggests that the quality of the surrounding cartilage influences outcome after cartilage repair surgery.

Knee dGEMRIC at 7 T: comparison against 1.5 T and evaluation of T1-mapping methods.

BACKGROUND: dGEMRIC (delayed Gadolinium Enhanced Magnetic Resonance Image of Cartilage) is a well-established technique for cartilage quality assessment in osteoarthritis at clinical field strengths. The method is robust, but requires injection of contrast agent and a cumbersome examination procedure. New non-contrast-agent-based techniques for cartilage quality assessment are currently being developed at 7 T. However, dGEMRIC remains an important reference technique during this development. The aim of this work was to compare T1 mapping for dGEMRIC at 7 T and 1.5 T, and to evaluate three T1-mapping methods at 7 T. METHODS: The knee of 10 healthy volunteers and 9 patients with early signs of cartilage degradation were examined at 1.5 T and 7 T after a single (one) contrast agent injection (Gd-(DTPA)2-). Inversion recovery (IR) sequences were acquired at both field strengths, and at 7 T variable flip angle (VFA) and Look-Locker (LL) sequences were additionally acquired. T1 maps were calculated and average T1 values were estimated within superficial and deep regions-of-interest (ROIs) in the lateral and medial condyles, respectively. RESULTS: T1 values were 1.8 (1.4-2.3) times longer at 7 T. A strong correlation was detected between 1.5 T and 7 T T1 values (r = 0.80). For IR, an additional inversion time was required to avoid underestimation (bias±limits of agreement - 127 ± 234 ms) due to the longer T1 values at 7 T. Out of the two 3D sequences tested, LL resulted in more accurate and precise T1 estimation compared to VFA (average bias±limits of agreement LL: 12 ± 202 ms compared to VFA: 25 ± 622 ms). For both, B1 correction improved agreement to IR. CONCLUSION: With an adapted sampling scheme, dGEMRIC T1 mapping is feasible at 7 T and correlates well to 1.5 T. If 3D is to be used for T1 mapping of the knee at 7 T, LL is preferred and VFA is not recommended. For VFA and LL, B1 correction is necessary for accurate T1 estimation.

Early osteoarthritis after slipped capital femoral epiphysis.

Background and purpose - Slipped capital femoral epiphysis (SCFE) results in a more or less pronounced deformity of the proximal femur, sometimes causing impingement and early osteoarthritis. We studied early osteoarthritis after SCFE and the association with deformity and self-reported hip function, pain, and quality of life. Patients and methods - 9 women and 16 men, mean age 32 (21-50) years, 19 with unilateral and 6 with bilateral SCFE, participated. All patients had primarily been operated by pin or screw with no attempt at reposition of the slip. Hips were examined by delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC), which quantifies and locates cartilage degeneration. Plain radiographs were used to measure deformity as determined by the alpha angle. Outcome was assessed by Oxford hip score, Hip Groin Outcome score and EQ-5D-Visual scale. Results - In the 19 unilateral SCFE, on the slip side dGEMRIC mean value was 533 ms (SD 112, range 357-649) versus mean 589 ms (SD 125, range 320-788) on the non-slip side, (p = 0.01). The dGEMRIC correlated negatively to the alpha angle, correlation coefficient (CC) = -0.60, (p = 0.002). Oxford hip score, pain, and EQ-5D-Visual scale correlated to dGEMRIC CC =0.43 (p = 0.03), CC =0.40 (p = 0.05), and CC =0.49 (p = 0.01) respectively. Interpretation - After SCFE, even relatively mild residual hip deformity can be associated with cartilage degeneration. A high alpha angle was associated with worse cartilage status. The Oxford hip score identified symptoms even though our patients had not previously sought medical care after the index operation. Quality of life showed strong inverse correlation with cartilage degeneration. Objective assessment of early cartilage degeneration may be useful for treatment decisions and follow-up.

Point of no return for improvement of cartilage quality indicated by dGEMRIC before and after weight loss in patients with knee osteoarthritis: a cohort study.

Background It has been demonstrated that weight loss improves symptoms in obese subjects with knee osteoarthritis (KOA). A parallel change in cartilage morphology remains to be demonstrated. Purpose To demonstrate a parallel change in cartilage morphology. Material and Methods Obese patients with KOA were examined before and after weight loss over 16 weeks. Target knee joints were radiographically assessed by the Kellgren/Lawrence grading (KLG) system. Patients with KLG-1 and 2 changes in the lateral compartment were included. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) was performed using intra-articular contrast. Results Nine patients with lateral KLG-1 and ten patients with lateral KLG-2 were studied. There were no group differences regarding the lateral compartment baseline dGEMRIC T1 values: median = 497 ms (KLG-1) and 533 ms (KLG-2) ( P = 0.12), or regarding reduction in body mass index (BMI) after 16 weeks: 12.8% versus 11.4% ( P = 0.74). In the KLG-1 group, several cases of increased dGEMRIC T1 values were seen and median value decreased significantly less than in KLG-2 group (15 ms versus 41 ms, P = 0.03) after weight loss. Conclusion Improvement of cartilage quality, assessed with dGEMRIC, after weight loss might be possible in early stage KOA (KLG-1), but not in later stage KOA (KLG-2). The results may suggest a point of no return for improvement of cartilage quality that should be tested in larger trials.

T2 mapping and post-contrast T1 (dGEMRIC) of the patellar cartilage: 12-year follow-up after patellar stabilizing surgery in childhood.

BACKGROUND: Cartilage degeneration has been reported after recurrent patellar dislocation. However, effects of surgical stabilization in childhood have not yet been described. PURPOSE: To examine the cartilage quality in very young adults operated with a patellar stabilizing procedure due to recurrent patellar dislocation in childhood, and evaluate if cartilage quality correlates with clinical parameters and patient-reported outcomes. MATERIAL AND METHODS: Seventeen patients were investigated ≥ 5 years (mean = 11.6 years) after patellar stabilizing surgery in childhood. Pre-contrast T2 relaxation times were analyzed in four superficial and four deep patellar cartilage regions of both knees. Two hours after 0.2 mM/kg Gd-DTPA2 i.v., post-contrast T1 (T1(Gd)) was analyzed in the same regions. Patient-reported outcomes (KOOS, Kujala, and Tegner scores) and recurrence rates were evaluated. RESULTS: Comparing operated to healthy side, neither T2 nor dGEMRIC differed between the operated and the reference knee regarding the superficial half of the cartilage. In the deep half of the cartilage, T1(Gd) was shorter in the central part of the cartilage, whereas T2 was longer medially (P < 0.05). A low score in the KOOS subscales Symptom and Sports & Recreation, was correlated to the degenerative changes detected by T1(Gd) (r = 0.5, P = 0.041). CONCLUSION: In general, our findings demonstrate good cartilage quality 12 years after patellar stabilizing surgery during childhood. The subtle changes in T2 and T1(Gd) in the deep cartilage layer may be a result of altered biomechanics, although very early degenerative changes cannot be excluded. The short T1(Gd) centrally may reflect lower glycosaminoglycan content, whereas the increase in T2 medially indicates increased cartilage hydration.

Time trends in pediatric fracture incidence in Sweden during the period 1950-2006.

Background and purpose - Pediatric fracture incidence may not be stable. We describe recent pediatric fracture epidemiology and etiology and compare this to earlier data. Patients and methods - The city of Malmö (population 271,271 in 2005) in Sweden is served by 1 hospital. Using the hospital diagnosis registry, medical charts, and the radiographic archive, we identified fractures in individuals <16 years that had occurred during 2005 and 2006. We also retrieved previously collected fracture data from between 1950 and 1994, from the hospital's pediatric fracture database. We used official population data to estimate period-specific fracture incidence (the number of fractures per 105 person-years) and also age- and sex-adjusted incidence. Differences are reported as rate ratios (RRs) with 95% confidence intervals. Results - The pediatric fracture incidence during the period 2005-2006 was 1,832 per 105 person-years (2,359 in boys and 1,276 in girls), with an age-adjusted boy-to-girl ratio of 1.8 (1.6-2.1). Compared to the period 1993-1994, age-adjusted rates were unchanged (RR =0.9, 95% CI: 0.8-1.03) in 2005-2006, with lower rates in girls (RR =0.8, 95% CI: 0.7-0.99) but not in boys (RR =1.0, 95% CI: 0.9-1.1). We also found that the previously reported decrease in unadjusted incidence in Malmö from 1976-1979 to 1993-1994 was based on changes in demography, as the age-adjusted incidences were similar in the 2 periods (RR =1.0, 95% CI: 0.9-1.1). Interpretation - In Malmö, pediatric fracture incidence decreased from 1993-1994 to 2005-2006 in girls but not in boys. Changes in demography, and also other factors, influence the recent time trends.

Delayed gadolinium-enhanced MRI of meniscus (dGEMRIM) and cartilage (dGEMRIC) in healthy knees and in knees with different stages of meniscus pathology.

BACKGROUND: Lesions in the meniscus are risk factors for developing knee osteoarthritis (OA), not least because of the role of the meniscus in the pathological progression of OA. Delayed gadolinium enhanced MRI of cartilage (dGEMRIC) has extensively been used to identify pre-radiographic cartilage changes in OA. In contrast, its counterpart with regard to examination of the meniscus, gadolinium enhanced MRI of meniscus (dGEMRIM), has been less utilized. In this study we use 3D dGEMRIM in patients with meniscus lesions and compare them with previous results of healthy individuals. METHODS: Eighteen subjects with MRI-verified posteromedial meniscus lesions and 12 healthy subjects with non-injured and non-symptomatic knee joints, together 30 volunteers, were examined using 3D Look-Locker sequence after intravenous injection of Gd-DTPA2- (0.2 mmol/kg body weight). Relaxation time (T1) was measured in the posterior meniscus and femoral cartilage before and 60, 90, 120 and 180 min after injection. Relaxation rate (R1 = 1/T1) and change in relaxation rate (ΔR1) were calculated. For statistical analyses, Student's t-test and Analysis of Variance (ANOVA) were used. RESULTS: The pre-contrast diagnostic MRI identified two sub-cohorts in the 18 patients with regard to meniscus injury: 1) 11 subjects with MRI verified pathological intrameniscal changes (grade 2) in the posteromedial meniscus only and no obvious cartilage changes. The lateral meniscus showed no pathology. 2) 7 subjects with MRI verified pathological rupture (grade 3) of the posteromedial meniscus and pathological changes in the lateral meniscus and/or medial and lateral joint cartilage. Comparisons of pathological and healthy posteromedial meniscus revealed opposite patterns in both T1Gd and ΔR1 values between pathological meniscus grade 2 and grade 3. The concentration of the contrast agent was lower than in healthy meniscus in grade 2 lesions (p = 0.046) but tended to increase in grade 3 lesions (p = 0.110). Maximum concentration of contrast agent was reached after 180 min in both cartilage and menisci (except for grade 3 menisci where the maximum concentration was reached after 90 min). CONCLUSION: dGEMRIM and dGEMRIC may be feasible to combine in vivo, preferably with one examination before and one 2 h after contrast injection. Possible different dGEMRIM patterns at different stages of meniscus lesions must be taken into account when evaluating meniscus pathology.

Early treatment with the von Rosen splint for neonatal instability of the hip is safe regarding avascular necrosis of the femoral head: 229 consecutive children observed for 6.5 years.

BACKGROUND AND PURPOSE: Avascular necrosis of the femoral head (AVN) is a complication in treatment of developmental dysplasia of the hip (DDH). We evaluated the risk of AVN after early treatment in the von Rosen splint and measured the diameter of the ossific nucleus at 1 year of age. CHILDREN AND METHODS: All children born in Malmö, Sweden, undergo clinical screening for neonatal instability of the hip (NIH). We reviewed 1-year radiographs of all children treated early for NIH in our department from 2003 through 2010. The diameter of the ossific nucleus was measured, and signs of AVN were classified according to Kalamchi-MacEwen. Subsequent radiographs, taken for any reason, were reviewed and a local registry of diagnoses was used to identify subsequent AVN. RESULTS: 229 of 586 children referred because of suspected NIH received early treatment (age ≤ 1 week) for NIH during the study period. 2 of the 229 treated children (0.9%, 95% CI: 0.1-3.1) had grade-1 AVN. Both had spontaneous resolution and were asymptomatic during the observation time (6 and 8 years). 466 children met the inclusion criteria for measurement of the ossific nucleus. Neonatally dislocated hips had significantly smaller ossific nuclei than neonatally stable hips: mean 9.4 mm (95% CI: 9.1-9.8) vs. 11.1 mm (95% CI: 10.9-11.3) at 1 year (p < 0.001). INTERPRETATION: Early treatment with the von Rosen splint for NIH is safe regarding AVN. The ossification of the femoral head is slower in children with NIH than in untreated children with neonatally stable hips.

Advanced Imaging in Femoroacetabular Impingement: Current State and Future Prospects.

Symptomatic femoroacetabular impingement (FAI) is now a known precursor of early osteoarthritis (OA) of the hip. In terms of clinical intervention, the decision between joint preservation and joint replacement hinges on the severity of articular cartilage degeneration. The exact threshold during the course of disease progression when the cartilage damage is irreparable remains elusive. The intention behind radiographic imaging is to accurately identify the morphology of osseous structural abnormalities and to accurately characterize the chondrolabral damage as much as possible. However, both plain radiographs and computed tomography (CT) are insensitive for articular cartilage anatomy and pathology. Advanced magnetic resonance imaging (MRI) techniques include magnetic resonance arthrography and biochemically sensitive techniques of delayed gadolinium-enhanced MRI of cartilage (dGEMRIC), T1rho (T1ρ), T2/T2* mapping, and several others. The diagnostic performance of these techniques to evaluate cartilage degeneration could improve the ability to predict an individual patient-specific outcome with non-surgical and surgical care. This review discusses the facts and current applications of biochemical MRI for hip joint cartilage assessment covering the roles of dGEMRIC, T2/T2*, and T1ρ mapping. The basics of each technique and their specific role in FAI assessment are outlined. Current limitations and potential pitfalls as well as future directions of biochemical imaging are also outlined.