PLOD2 gene expression in infrapatellar fat pad is correlated with fat mass in obese patients with end-stage knee osteoarthritis.

Objective: To investigate associations between obesity-linked systemic factors and gene expression indicative for the inflammatory and fibrotic processes in the infrapatellar fat pad (IFP), in a population of obese patients with end-stage knee osteoarthritis (KOA). Methods: We collected human IFPs from 48 patients with a mean body mass index (BMI) of 35.44 â€‹kg/m2 during total knee replacement procedures. These patients were part of a randomized controlled trial and met the criteria of having OA and a BMI of ≥30 â€‹kg/m2. Blood samples were collected to assess serum levels of glucose, total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, and leptin. Total body composition was measured using dual-energy X-ray absorptiometry. Gene expressions of IL6, TNFA, COL1A1, IL1B, ASMA, PLOD2 in the IFP were analyzed. Results: Univariate analysis resulted in a positive correlation between BMI and procollagen-lysine,2-oxoglutarate 5-dioxygenase 2 (PLOD2) expression (r2 â€‹= â€‹0.13). In univariate analyses of obesity-linked systemic factors and PLOD2, significant correlations were found for lean mass (r2 â€‹= â€‹0.20), fat mass (r2 â€‹= â€‹0.20), serum cholesterol (r2 â€‹= â€‹0.17), serum triglycerides (r2 â€‹= â€‹0.19) and serum leptin (r2 â€‹= â€‹0.10). A multiple linear regression model indicated fat mass to be a strong predictor of PLOD2 production in the IFP (r2 â€‹= â€‹0.22, P â€‹= â€‹0.003). Conclusion: Our study demonstrates the positive association between fat mass and PLOD2 expression in the IFP of obese end-stage knee OA patients. This may indicate that within this patient population the fibrotic process in the IFP is influenced by systemic adipose tissue, next to local inflammatory processes.

Hip kinematics and kinetics in patients with femoroacetabular impingement syndrome before and 1 year after hip arthroscopic surgery. Results from the HAFAI cohort.

INTRODUCTION: Patients with femoroacetabular impingement syndrome (FAIS) experience decreased function. Consequently, earlier studies have evaluated gait biomechanics in these patients, but a larger study evaluating gait biomechanics before and after an intervention standardising gait speed is lacking. We aimed at investigating gait kinematics and kinetics in patients with FAIS compared with pain-free controls before and 1 year after hip arthroscopic surgery. Secondary, we aimed at analysing gait pattern separately for the sexes and to investigate associations between peak kinematics and kinetics and the Copenhagen Hip and Groin Outcome Score (HAGOS). MATERIALS AND METHODS: Sixty patients with FAIS and 30 pain-free controls were tested at a standardised gait speed (1.40 m/s ± 10%). Patients were tested twice: before and 1 year after surgery. Kinematics and kinetics were recorded using infrared high-speed cameras and a force plate. Participants answered HAGOS. RESULTS: The largest difference among groups was that gait differed between males and females. Neither before nor after surgery could we demonstrate large alterations in gait pattern between patients and pain-free controls. Male patients demonstrated associations between peak kinematics and kinetics and HAGOS Sports function. CONCLUSIONS: Gait pattern was only vaguely altered in patients with FAIS compared with pain-free controls before and after surgery when using at standardised gait speed. Hence, analysing gait in patients with FAIS does not seem of major importance. Nevertheless, there was an association between HAGOS Sports function and peak kinematics and kinetics in male patients, implying that there could be a clinical importance.

Weight Loss Intervention Before Total Knee Replacement: A 12-Month Randomized Controlled Trial.

BACKGROUND AND AIMS: Obesity is an increasing problem in patients after total knee replacement. The aim of this study was to investigate whether a weight loss intervention before primary total knee replacement would improve quality of life, knee function, mobility, and body composition 1 year after surgery. MATERIAL AND METHODS: Patients scheduled for total knee replacement due to osteoarthritis of the knee and obesity were randomized to a control group receiving standard care or to an intervention group receiving 8-week low-energy diet before total knee replacement. Patient-reported quality of life, 6-Min Walk Test, and body composition by dual-energy X-ray absorptiometry were assessed before intervention for the diet group, and within 1 week preoperatively for both groups, and the changes in outcome from baseline to 1 year after total knee replacement were compared between groups. The number of participants was lower than planned, which might introduce a type-2 error and underestimate the trend for a better outcome after weight loss. RESULTS: The analyses are based on a total of 76 patients, 38 in each group. This study showed major improvement in both study groups in quality of life and knee function, though no statistically significant differences between the groups were observed 1 year after total knee replacement. The average weight loss after 8-week preoperative intervention was 10.7 kg and consisted of a 6.7 kg reduction in fat mass. One year after total knee replacement, the participants in the diet group managed to maintain the weight reduction, whereas there was no change in the control group. CONCLUSION: The results suggest that it is feasible and safe to implement an intensive weight loss program shortly before total knee replacement. The preoperative intervention resulted in a 10% body weight loss, improved body composition, lower cardiovascular risk factors, and sustained s-leptin.

No association between femoral or acetabular angles and patient-reported outcomes in patients with femoroacetabular impingement syndrome-results from the HAFAI cohort.

Patients with femoroacetabular impingement syndrome (FAIS) are diagnosed using imaging, but detailed description especially the acetabular shape is lacking and may help give more insight to the pathogenesis of FAIS. Furthermore, associations between patient-reported outcomes (PROs) and the radiological angles might highlight which radiological angles affect outcomes experienced by the patients. Hence, the aims of this study were (i) to describe computer tomography (CT) acquired angles in patients with FAIS and (ii) to investigate the association between radiological angles and the Copenhagen Hip and Groin Outcome Score (HAGOS) in patients with FAIS. Patients scheduled for primary hip arthroscopic surgery for FAIS were included. Based on CT, following angles were measured before and 1 year after surgery; femoral anteversion, alpha, lateral centre edge, acetabular index, anterior sector, posterior sector and acetabular anteversion. All patients completed the HAGOS. Sixty patients (63% females) aged 36 ± 9 were included. One year after surgery, significant alterations in the alpha angle and the acetabular index angle were found. Neither baseline PROs nor changes in PROs were associated with the radiological angles or changes in angles. Since neither changes in CT angles nor baseline scores were associated with HAGOS, the improvements felt by patients must origin from somewhere else. These findings further underlines that morphological changes seen at imaging should not be treated arthroscopically without a patient history of symptoms and clinical findings.

Is hip muscle strength normalised in patients with femoroacetabular impingement syndrome one year after surgery?: Results from the HAFAI cohort.

OBJECTIVES: Little is known about hip function after hip arthroscopic surgery in patients with femoroacetabular impingement syndrome. Hence, the aim of the study was (1) to investigate changes in hip muscle strength from before to one year after hip arthroscopic surgery, (2) to compare patients with a reference group. DESIGN: Cohort study with a cross-sectional comparison. METHODS: Before and after hip arthroscopic surgery, patients underwent hip muscle strength testing of their hip flexors and extensors during concentric, isometric and eccentric contraction in an isokinetic dynamometer. Reference persons with no hip problems underwent tests at a single time point. Participants completed completed the Copenhagen Hip and Groin Outcome Score (HAGOS) questionnaire and physical capacity (stair climbing loaded and unloaded, stepping loaded and unloaded and jumping) tests. RESULTS: After surgery, hip flexion strength improved during all tests (6-13%, p<0.01) and concentric hip extension strength improved (4%, p=0.002). Hip flexion and extension strength was lower for patients than for reference persons (9-13%, p<0.05) one year after surgery. Higher hip extension strength after surgery was associated with better patient reported outcomes. Patients, who were unable to complete at minimum one test of physical capacity, demonstrated significantly weaker hip muscle strength. Compared with their healthy counterparts, female patients were more impaired than male patients. CONCLUSIONS: One year after surgery, patients improved their maximal hip muscle strength. When compared to reference persons, maximal hip muscle strength was still impaired.

Does a titanium sleeve reduce the frequency of pseudotumors in metal-on-metal total hip arthroplasty at 5-7years follow-up?

INTRODUCTION: Little is known about pseudotumor frequency and risk factors for pseudotumor formation among different types of metal-on-metal (MoM) hip arthroplasties. A lower release of chromium and cobalt have been reported in MoM hip arthroplasties with a titanium sleeve compared to MoM designs without a titanium sleeve, but yet it is unknown whether a titanium sleeve reduces the pseudotumor frequency. We conducted a cross-sectional study to investigate: 1) pseudotumor frequency, 2) risk factors of pseudotumor formation 3) and correlations between pseudotumors, serum metal-ions, implant position, and clinical symptoms. HYPOTHESIS: We expected a lower pseudotumor frequency in MoM hip articulation with a titanium sleeve than reported in MoM hip articulation designs using chromium-cobalt sleeve. MATERIALS AND METHOD: A consecutive series of 41 patients/49 hips (31 males), mean age 52 (28-68) years, participated in a 5.5±0.5 (4-6.5) year follow-up study of their M2a_Magnum hip articulation (Biomet Inc., Warsaw, Indiana, USA). Patients were evaluated with magnetic resonance imaging (MRI), measurements of serum metal-ions, plain radiographs, and clinical outcome measures of Harris Hip Score (HHS) and Oxford Hip Score (OHS). RESULTS: Eighteen of 47 hips (38%) had MRI-verified pseudotumors, all cystic, with a mean dimension of 10.6×25.6×41mm. Digital measurements on plain radiographs revealed a higher cup anteversion in patients with a pseudotumor of mean 28.4°±5.05° compared to mean 23.5°±6.5° in patients without a pseudotumor (P=0.009). Serum metal-ion concentrations, acetabular cup inclination and measures of HHS and OHS were similar between patients with and without a pseudotumor (P>0.46). CONCLUSION: At 5.5±0.5years after surgery, MRI-verified cystic pseudotumors were frequently observed in M2a_Magnum hip articulations despite the use of titanium sleeves. The pseudotumors were related to high cup anteversion angles but not related to high serum metal-ions or clinical symptoms. LEVEL OF EVIDENCE: IV: cross-sectional study.

Effect of early supervised progressive resistance training compared to unsupervised home-based exercise after fast-track total hip replacement applied to patients with preoperative functional limitations. A single-blinded randomised controlled trial.

OBJECTIVE: To examine if 2 weekly sessions of supervised progressive resistance training (PRT) in combination with 5 weekly sessions of unsupervised home-based exercise is more effective than 7 weekly sessions of unsupervised home-based exercise in improving leg-extension power of the operated leg 10 weeks after total hip replacement (THR) in patients with lower pre-operative function. METHOD: A total of 73 patients scheduled for THR were randomised (1:1) to intervention group (IG, home based exercise 5 days/week and PRT 2 days/week) or control group (CG, home based exercise 7 days/week). The primary endpoint was change in leg extension power at 10 week follow up. Secondary outcomes were isometric hip muscle strength, sit-to-stand test, stair climb test, 20 m walking speed and patient-reported outcome (HOOS). RESULTS: Sixty-two completed the trial (85%). Leg extension power increased from baseline to the 10 week follow up in both groups; mean [95% CI] IG: 0.29 [0.13; 0.45] and CG: 0.26 [0.10; 0.42] W/kg, with no between-group difference (primary outcome) (P = 0.79). Maximal walking speed (P = 0.008) and stair climb performance (P = 0.04) improved more in the IG compared to CG, no other between-group differences existed. CONCLUSIONS: In this trial, supervised PRT twice a week in addition to 5 weekly sessions of unsupervised exercise for 10 weeks was not superior to 7 weekly sessions of unsupervised home-based exercise for 10 weeks in improving the primary outcome, leg-extension power of the operated leg, at the primary endpoint 10 weeks after surgery in THR patients with lower pre-operative function. TRIAL REGISTRATION: NCT01214954.

Block-step asymmetry 5 years after large-head metal-on-metal total hip arthroplasty is related to lower muscle mass and leg power on the implant side.

BACKGROUND: Metal-on-metal articulations mimic the human hip anatomy, presumably lower dislocation rates and increase the range-of-motion. This study aims to measure the muscle mass and power of both legs in patients with unilateral metal-on-metal total hip arthroplasty, and to investigate their effect on block-step test, spatio-temporal gait parameters and self-reported function. METHODS: Twenty-eight patients (7 women), mean age 50 (28-68) years, participated in a 5-7 year follow-up. Patients had received one type unilateral large-head metal-on-metal total hip articulation, all of which were well-functioning at follow-up. Mean muscle mass was measured by the total-body Dual energy X-ray Absorption scans, and muscle power was measured in a leg extensor power rig. Block-step test and spatio-temporal gait parameters were measured with an inertial measurement unit. Self-reported function was assessed by the Hip Disability and Osteoarthritis Outcome Score. FINDINGS: We found a significant difference between the mean muscle mass of the implant-side leg and the non-implant-side leg in hip, thigh and calf areas (P<0.008) and in mean muscle power (P=0.025). Correlations between mean muscle mass and mean muscle power were significant for both the implant-side leg (r=0.45, P=0.018) and the non-implant-side leg (r=0.51, P=0.007). The difference in mean muscle power between legs correlated with block-step test asymmetry during ascending (r=0.40, P=0.047) and descending (r=0.53, P=0.006). Correlations between self-reported function and power of the implant-side leg were not significant. INTERPRETATIONS: Young patients have not fully regained muscle mass, muscle power and function 5-7 years after metal-on-metal total hip arthroplasty.

Does reduced movement restrictions and use of assistive devices affect rehabilitation outcome after total hip replacement? A non-randomized, controlled study.

BACKGROUND: Improvements in surgical techniques and increase of femoral head size might have changed the rationale for movement restrictions after total hip replacement (THR). AIM: To evaluate the influence of movement restrictions and assistive devices on rehabilitation after fast track THR. DESIGN: Non-randomized, controlled study. SETTING: Inpatient. POPULATION: 365 consecutively included THR patients. METHODS: Patients included the 3 initial month of the study underwent rehabilitation with restrictions in hip movement and a standard package of assistive devices (restricted group). This group was compared to patients included the following 3 months with less restricted hip movement and use of assistive devices according to individual needs (unrestricted group). Questionnaires on function, pain, quality of life (HOOS), anxiety (HADS), working status and patient satisfaction were completed before THR, 3 and 6 weeks after. RESULTS: The HOOS function score at the 3 measurement times was (mean ± SD); unrestricted group: 46 ± 17 - 76 ± 9 - 83 ± 14 compared to restricted group: 43 ± 16 - 81 ± 14 - 83 ± 13. Changes over time was significantly higher in the restricted group (P=0.004). Return to work 6 weeks after THR for the unrestricted group compared to restricted group was: 53% versus 32% (P=0.045). No significant differences between groups in pain, symptoms, quality of life, anxiety/depression, hip dislocations and patient satisfaction. CONCLUSION: This study showed slightly slower recovery in patient-reported function after reduction in movement restrictions and use of assistive devices, but the difference was eliminated after 6 weeks. Reduced movement restrictions did not affect the other patient-reported outcomes and led to earlier return to work. CLINICAL REHABILITATION IMPACT: It is possible to reduce movement restrictions and use of assistive devices considerably. More research on safety issues is needed to elucidate the effect of unrestricted rehabilitation on hip dislocation.

Cartilage thickness in the hip joint measured by MRI and stereology--a methodological study.

OBJECTIVE: The purpose of this study was to develop a precise and efficient method for estimating the thickness of the articular cartilage in the hip joint and hence three different stereologic methods were tested based on Magnetic Resonance Imaging. DESIGN: Twenty two females and four males with hip dysplasia underwent MRI. The thickness of the femoral and acetabular cartilage was estimated. RESULTS: The results for all three methods showed that the observed total variance on cartilage thickness is small. The mean thickness of the acetabular cartilage measured by the three different methods ranged between 1.15 mm and 1.46 mm. The mean thickness for the femoral cartilage measured by the three different methods ranged between 1.18 mm and 1.78 mm. The measurements took 15-20 min per hip to carry out. CONCLUSION: Methods 1 and 3 are as precise but we favour method 3 because the measurements are done on images obtained through the center of the femoral head which means that the cartilage surface is intersected perpendicular and partial volume effect avoided. We suggest that this method can be advantageous for assessing the progression of osteoarthritis in dysplastic hips after periacetabular osteotomy.

Prospective bone density changes after periacetabular osteotomy: a methodological study.

We used computed tomography (CT) and 3D design-based sampling principles (stereology) to estimate changes in acetabular bone density after periacetabular osteotomy. We included six consecutive patients with hip dysplasia in the study. Baseline density was measured within the first 7 days following periacetabular osteotomy and compared with bone density 2 years later. Double measurements were performed on three patients, and the coefficient of error of the mean was estimated to 0.05. Bone density in zone 1 increased significantly in the anteromedial quadrant as well as in the posteromedial quadrant of the acetabulum. In the anterolateral and the posterolateral quadrant, bone density was unchanged. In zone 2 and 3, bone density was unchanged 2 years postoperatively. We suggest that the observed increase in bone density medially represents a remodelling response to an altered load distribution after osteotomy. The method used is a precise tool to estimate changes in acetabular bone density.