Influence of body mass index on revision rates after primary total knee arthroplasty.

PURPOSE: Studies demonstrate that revision rates after primary total knee arthroplasty (TKA) tend to be higher in obese patients. However, the existence of a body mass index (BMI) threshold remains unexplored. METHODS: We conducted a prospective cohort study of 2442 primary TKAs in 2035 patients (69.1 % women; mean age 72 years; mean follow-up 93 months, range 38-203). We evaluated the influence of BMI in five categories on all-cause revision after TKA using incidence rates (IR), hazard ratios (HR), and Kaplan-Meier survival analysis. Adjustment for baseline imbalances was performed using Cox regression analysis. RESULTS: Over the study period, 71 revisions occurred. Revision rates were 3.2 cases/1000 patient-years for patients of normal weight, 3.4/1000 for overweight patients and 3.0/1000 for patients classified as obese class I. At BMI ≥ 35, a significant increase in revision was noted. Comparing BMI ≥ 35 vs. < 35, there were 6.4 vs. 3.2 /1000. Crude HR was 2.0 [95 % confidence interval (CI) 1.2-3.3, p = 0.009], and the adjusted HR was 2.1 (95 % CI 1.2-3.6, p = 0.008). CONCLUSION: All-cause revision rates after primary TKA doubled in patients with a BMI of 35 but were similar in those with a BMI <35.

How gait and clinical outcomes contribute to patients' satisfaction three months following a total knee arthroplasty.

The objective of this study was to investigate how gait and clinical outcomes contribute to patients' satisfaction three months following a total knee arthroplasty (TKA). Seventy-eight patients with knee osteoarthritis (OA) and a control group of twenty-nine subjects were evaluated. The gait parameters, Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain and functional levels, quality of life and patients' satisfaction following TKA were assessed. A multiple linear regression model shows that the WOMAC functional score explained 39% of the global satisfaction and 37% of the satisfaction related to pain relief following TKA. Finally, the model shows that 65% of the satisfaction related to the functional improvement was explained by a combination of clinical and gait parameters. This study demonstrated the contribution of both gait and clinical outcomes to patients' satisfaction following TKA.

Do synovial leptin levels correlate with pain in end stage arthritis?

PURPOSE: We evaluated whether synovial fluid (SF) leptin concentrations correlate with pain severity in patients with hip or knee endstage osteoarthritis (OA) and whether they mediate the association between increased joint pain and (1) female gender and (2) obesity. METHODS: We conducted a cross-sectional study including patients with primary hip and knee OA undergoing joint replacement between January and December 2010. SF leptin concentrations obtained on the day of surgery were assessed. Main outcome was pain severity measured pre-operatively using WOMAC and VAS pain scales. RESULTS: A total of 219 patients were included, 123 hip and 96 knee arthroplasties. Mean age was 72 years, 59% were women. Mean SF leptin levels were 22.9 (±25.6) ng/ml in women and 5.4 (±5.9) ng/ml in men. Levels >19.6 ng/ml (highest quartile) were significantly associated with increased pain on both WOMAC (mean difference -9.6, 95% CI -15.1 to -4.0) and VAS scale (mean difference 0.8, 95% CI 0.2-1.3). Associations remained unchanged after adjusting for age, co-morbidities, contra-lateral arthritic joint, OA site, and disability. The associations observed between increased pain and female gender or obesity were substantially reduced after adjusting for SF leptin. CONCLUSION: Joint pain is associated with SF leptin concentrations. Increased pre-operative pain observed in women and obese may be related to high intra-articular leptin levels.

[What's new after an ACL tear?]. / Déchirure du ligament croisé antérieur: quoi de neuf?

Following a severe knee sprain during which the anterior cruciate ligament has been torn, the patient and his doctor are facing the choice between a conservative treatment or a surgical approach. Reviewing the international literature allows us to build a pertinent opinion. If the conservative treatment is selected, one must be aware that the proportion of good results does not exceed 50%. This is why, this treatment is only recommended for little demanding and non-sports active persons. In various surgical options, the autologous anterior cruciate ligament reconstruction, using a graft of patellar or hamstrings tendons gives good, reliable and reproducible results.

Epidemiology of injuries in professional ice hockey: a prospective study over seven years.

BACKGROUND: Ice hockey injuries epidemiology is still poorly understood and very few studies are focused on it, especially about professional players. METHODS: Our prospective study collected all injuries occurring on ice during practice and games over 7 years (2006-2013) in a professional hockey team playing in the 1st division championship in Switzerland. RESULTS: During the 7 seasons, we recorded a total of 525 injuries and 190 injuries with time loss (TL). Mean injuries incidence was 5.93 (95% CI 5.28 to 6.27) injuries/1000 h/player and with time loss 2.14 (95% CI 1.79 to 2.39) injuries/1000 h/player. The lower limb was the most affected part of the body, with a total of 40.4% of all injuries, mostly knee Medial Collateral Ligament tear and muscle adductors/abdominal sprain. For the upper limb, shoulder was the most affected joint with mostly acromioclavicular sprain and shoulder dislocation. Forwards had a significant (p < 0.05) higher risk than defensemen for knee Medial Collateral Ligament (MCL) tear. There was no significant difference in the concussion risk between forwards and defensemen, but defensemen had a significant higher risk (p < 0.05) to have a more severe concussion. CONCLUSION: This study provides a better understanding about professional ice hockey epidemiology, which is still insufficiently researched and understood. We also found some significant risk factors, being a forward for knee MCL tear, being a defensemen for concussion severity. Concussion program prevention seems to be effective but it is crucial to continue the follow up of concussion on long term and expand the surveillance system to all the League.

Matrix-Augmented Bone Marrow Stimulation With a Polyglycolic Acid Membrane With Hyaluronan vs Microfracture in Local Cartilage Defects of the Femoral Condyles: A Multicenter Randomized Controlled Trial.

BACKGROUND: Microfracture (MF) is an established operative treatment for small, localized chondral defects of the knee joint. There is evidence from animal studies that matrix augmentation of bone marrow stimulation (m-BMS) can improve the quality of the repair tissue formation. PURPOSE: To evaluate the therapeutic outcome of a matrix made of polyglycolic acid and hyaluronan as compared with a conventional MF technique. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: Patients between the ages of 18 and 68 years who had an articular femoral cartilage defect of 0.5 to 3 cm2 in the weightbearing area of the femoral condyles with indication for MF were included in this study. Patients were randomized and treated with either MF or m-BMS with Chondrotissue. Defect filling, as assessed on magnetic resonance imaging (MRI), at postoperative 12 weeks was defined as the primary outcome measure, with follow-up MRI at weeks 54 and 108. Follow-up data were also collected at 12, 54, and 108 weeks after surgery and included patient-reported clinical scores: visual analog scale for pain, Knee injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee score, and 36-Item Short Form Health Survey. RESULTS: MRI scans confirmed cartilage repair tissue formation in both groups 12 weeks after treatment. There was no significant difference between the m-BMS and MF groups in the percentage of defect filling at 12, 54, and 108 weeks postoperatively. No significant difference was found in terms of patient-reported clinical scores. Both groups showed significant improvement in 4 KOOS subscales-Pain, Activities of Daily Living, Sport and Recreation, and Quality of Life-at 54 and 108 weeks after treatment. CONCLUSION: This is the first randomized controlled trial comparing m-BMS with a polyglycolic acid matrix with hyaluronan with MF. The use of the Chondrotissue implant in m-BMS has been proven to be a safe procedure. No difference was found between m-BMS and MF in terms of patient-reported outcome scores and MRI assessment until postoperative 2 years. Long-term follow-up studies including histological assessment are desirable for further investigation. REGISTRATION: EUCTR2011-003594-28-DE (EU Clinical Trials Register).

[Severe knee sprain: which surgery and for whom?]. / Entorse grave du genou: quelle intervention et pour qui?

After a knee sprain, some anamnestic and clinical elements may suspect and eventually establish the diagnosis. The association of a crack, an hemarthrosis and a knee joint laxity correspond to a severe sprain. The initial management of a traumatic knee is essential because it leads to the good treatment option. Misdiagnosed lesions often do not heal optimally and induce new traumas synonymous of functional impairment and handicap.

Development of a force amplitude- and location-sensing device designed to improve the ligament balancing procedure in TKA.

To improve the ligament balancing procedure during total knee arthroplasty a force-sensing device to intraoperatively measure knee joint forces and moments has been developed. It consists of two sensitive plates, one for each condyle, a tibial base plate and a set of spaces to adapt the device thickness to the patient-specific tibiofemoral gap. Each sensitive plate is equipped with three deformable bridges instrumented with thick-film piezoresistive sensors, which allow accurate measurements of the amplitude and location of the tibiofemoral contact forces. The net varus-valgus moment is then computed to characterize the ligamentous imbalance. The developed device has a measurement range of 0-500 N and an intrinsic accuracy of 0.5% full scale. Experimental trials on a plastic knee joint model and on a cadaver specimen demonstrated the proper function of the device in situ. The results obtained indicated that the novel force-sensing device has an appropriate range of measurement and a strong potential to offer useful quantitative information and effective assistance during the ligament balancing procedure in total knee arthroplasty.

Expert panel on anterior cruciate ligament case studies.

Anterior cruciate ligament (ACL) reconstructions cannot, and should not, be considered "recipe-driven" or "cookie-cutter" operations. There are multiple variables that must be considered both pre- and intraoperatively in order to execute a successful procedure. The following case studies present a number of challenging situations, many of which do not have a straightforward, or only one, solution. The goal is to provide some ral-life clinical situations in which the reader can "observe" an expert panel of ACL surgeons working through the problems--offering solutions based on science, experience, and intuition.

Does knee alignment influence gait in patients with severe knee osteoarthritis?

BACKGROUND: Patients with knee osteoarthritis present an altered gait pattern. Amongst many factors, the lower limb alignment (varus, valgus) has been identified as an important risk factor for the progression of knee osteoarthritis. Among the large number of studies on knee osteoarthritis gait, only a few have included patients with a valgus deformity. The aims of this study were to determine how knee alignment influences full-body gait in patients with knee osteoarthritis and if knee malalignment is associated with pain and functional capacity. METHODS: Sixty patients with severe knee osteoarthritis scheduled for a total knee arthroplasty were included in this study. Twenty-six subjects were recruited as the control group. The spatio-temporal parameters, three-dimensional full-body kinematics, and lower body kinetics were evaluated during a comfortable gait and compared between the groups. Pain and function were assessed with the WOMAC questionnaire. FINDINGS: The full-body gait analysis demonstrated substantially different gait patterns and compensation mechanisms between the three groups. Patients with varus knee alignment significantly augmented their trunk movements in sagittal and frontal planes compared to patients with a valgus knee. In addition, patients with a valgus knee reported lower pain and lower functional deficits compared to patients with a varus knee. INTERPRETATION: We found that gait compensations were significantly influenced by lower limb alignment. These new insights related to different knee osteoarthritis gait patterns might help in the understanding of gait compensation behaviours prior to total knee arthroplasty and better manage the strategies of rehabilitation following surgery.

Influence of CYP2D6 activity on pre-emptive analgesia by the N-methyl-D-aspartate antagonist dextromethorphan in a randomized controlled trial of acute pain.

BACKGROUND: There is some evidence that dextromethorphan (DM) is effective as a pre-emptive analgesic agent.  DM is mainly metabolized to dextrorphan (DOR) by CYP2D6 whose activity can be inhibited by pharmacologic intervention. OBJECTIVES: To investigate the efficacy of DM as a pre-emptive analgesic agent and describe the population pharmacokinetics in the presence of normal and poor CYP2D6 metabolism in acute post-operative pain. STUDY DESIGN: Double blind, randomized, placebo-controlled trial SETTING: Post-surgical analgesic consumption after knee ligament surgery, a setting of acute pain. METHODS: Forty patients were randomized to a single oral dose of 50 mg quinidine or placebo, administered 12 hours before 50 mg DM. Patients were genotyped for the major CYP2D6 and ABCB1 variants and phenotyped for CYP2D6 using urine DM/DOR metabolic ratios and blood samples for population pharmacokinetic modeling. RESULTS: Quinidine was effective in inhibiting CYP2D6 activity, with 2-fold reduction of DM to DOR biotransformation clearance, prolonged DM half-life, and increased DM systemic availability. Patients in the quinidine group required significantly less often NSAIDs than patients in the placebo group (35.3% vs. 75.0%, P = 0.022). The odds ratio for NSAID consumption in the placebo vs. quinidine group was 5.5 (95% confidence interval (CI) 1.3 - 22.7) at 48 hours after surgery. LIMITATIONS: While this study shows an impact of DM on pre-emptive analgesia and is mechanistically interesting, the findings need to be confirmed in larger trials. CONCLUSION: CYP2D6 inhibition by quinidine influenced the pre-emptive analgesic effectiveness of DM confirming that CYP2D6 phenotypic switch increases the neuromodulatory effect of oral dextromethorphan.

Sit-to-stand alterations in advanced knee osteoarthritis.

This study investigated the full-body strategies utilized during a sit-to-stand (STS) task in patients with knee osteoarthritis (OA) and the association between STS alterations and clinical measurements. Twenty-five patients with advanced knee OA and twenty healthy elderly adults were recruited to participate in this study. Patients were asked to stand up from a chair four times without using their arms. A 3D motion analysis system was used to capture the full-body kinematics during the task. Two force plates were used to capture the forces under each leg. The following parameters were investigated in the knee OA group and compared with the control group: the time to realize STS, the force ratio between both limbs, the knee and hip kinetics and the trunk kinematics. The pain and functional capacity were obtained from the WOMAC. The results showed that patients with knee OA put 10% additional weight on the contralateral side when compared with the symmetrical strategy of the control group. Patients with knee OA showed a significantly lower knee flexion moment (0.51 Nm/kg vs. 0.72 Nm/kg), a higher maximal trunk flexion (46.4° vs. 37.5°), and a higher lateral trunk lean on the contralateral side (2.4° vs. 0.9°) when compared with the control group. The main correlations were found between pain and the averaged time to complete the STS task (r=0.55). With the quantification of the full-body mechanisms utilized during the STS task, which includes both distal and proximal compensations, our study brings new insights, leading to a better understanding of the functional alterations in patients with advanced knee OA.

α-Smooth muscle actin and TGF-ß receptor I expression in the healing rabbit medial collateral and anterior cruciate ligaments.

The aim of our study was to advance the knowledge about the biological differences in the healing of the anterior cruciate ligament (ACL) versus the medial collateral ligament (MCL). We quantified α-smooth muscle actin (α-SMA) expression and TGF-ß receptor I (TGF-ßRI) expression in experimentally injured rabbit ligaments (from day 3 to 12 weeks post-injury). Myofibroblasts (α-SMA positive cells) were identified as early as the third day post-injury in MCL and their density increased steadily up to day 21. Myofibroblasts were also detected in injured ACL but their density remained very low at all time points. The percentage of positive TGF-ßRI area significantly increased in both injured ligaments compared to controls, with a peak expression at day 21; however, it remained constantly lower in ACL compared to MCL. A significant correlation was found between the percentage of TGF-ßRI positive cells and the percentage of α-SMA expression only in injured MCL. These results provide evidence that myofibroblasts are important players in MCL remodelling after injury. The combined presence of myofibroblasts and TGF-ßRI in the first 3 weeks post-MCL injury may partially explain the difference in the MCL and ACL healing process.