Purpose. Whether the presence of knee effusion in individuals with knee osteoarthritis (OA) affects periarticular neuromuscular control during gait and thus the joint loading environment is unknown. The purpose was to test the hypothesis that knee effusion presence alters periarticular neuromuscular patterns during gait in individuals with moderate knee OA. Method. 40 patients with medial compartment knee OA participated after giving informed consent. Patients were assessed for the presence of effusion using a brush test and were assigned to the knee effusion (n=20) and no knee effusion (n=20) groups. Surface electrodes were placed in a bipolar configuration over the lateral and medial gastrocnemius, vastus lateralis and medialis, rectus femoris and the lateral and medial hamstrings of the affected limb. Five trials of self-selected walking were completed. Electromyograms (EMG) were collected using an AMT-8 EMG system (Bortec Inc.). An Optotrak motion capture system (Northern Digital Inc.) recorded leg motion. Euler rotations were used to derive knee angles. EMG waveforms were low-pass filtered and amplitude normalized to maximal effort voluntary isometric contractions. Quadriceps, gastrocnemius and hamstring strength was measured from torques produced against a Cybex dynamometer. Principal Component Analysis extracted the predominant waveform features and weighting scores were calculated for each measured waveform. Analysis of variance models test for main effects (group, muscle) and interactions (alpha = 0.05). Bonferonni post hoc testing was employed. Results. No differences in age, body mass index, knee pain, Western Ontario McMaster Osteoarthritis Index scores, gait velocity and muscle strength were found between groups (p>0.05). Gastrocnemius activation was not influenced by the presence of effusion (p>0.05). For individuals with effusion, a greater overall quadriceps activation was found and a prolonged hamstring activation into mid-stance only (p<0.05). Range of motion excursion from heel strike to peak extension during terminal stance was greater with effusion (p<0.05). Conclusion. The hypothesis that knee effusion in those with moderate knee OA is associated with alterations in quadricep and hamstring muscle activation patterns and sagittal plane knee motion during gait was supported. Quadriceps muscle inhibition during the normalization exercises may provide a partial explanation, consistent with results from acute effusion models. However, the hamstring alteration during mid-stance only, no strength differences between the two groups and altered kinematics support that mechanisms other than muscle inhibition are responsible for the altered patterns. These novel findings are a first step at understanding the effects of knee effusion on periarticular muscle function during gait that subsequently can affect the mechanical environment of the joint in those with a more chronic effusion

Salmonella osteomyelitis occurs infrequently in children without a sickle cell disease, and its subacute form is rare. Diagnosis is often delayed because its slow onset, intermittent pain and it can be confused with bone tumors. An otherwise healthy 13-year-old boy was admitted from another center in order to discard bone tumor in proximal tibia, with compatible radiologic findings. There was no history of trauma or previous illness. Twenty days ago, he had flu symptoms and myalgia. On the physical examination the child was feverless, showed increased heat over his left knee, considerable effusion and painful restriction of movement. Inflammatory laboratory results revealed erythrocyte sedimentation rate 46mm/h and C-Reactive protein, 11,2 mg/L. Radiographs revealed a lytic lesion localized in the proximal metaphysis and epiphysis. The MRI showed an area of edema around the lytic lesion and surrounding soft tissues. Images supported the diagnosis of subacute osteomyelitis, (Brodie abscess). Empirically, intravenous cefuroxime was started. Forty-eight hours post admission, the patient underwent abscess surgical debridement, washout and cavity curettage. Samples were sent for cytology, culture and sensitivity and acid fast bacilli culture and sensitivity. Collection´s count cell was 173.000/ L white cells. Collection´s culture revealed Salmonella B sensitive to ciprofloxacin. Stool culture did not yield any growth. Intravenous cefuroxime was administered during 10 days. The patient responded well as evidenced by clinical and laboratory improvement He was discharged with his left leg immobilized in a cast during 1 month and treatment was completed with oral ciprofloxacin 500mg /12 h during 2 months. The patient had full range of knee motion after 2 months. Last reviewed, after two years of the income, he was completed recovered, and the radiograph showed bone healing without physeal neither damage nor limb leg discrepancy. The most effective therapy of a confirmed salmonella osteomyelitis is a combination of radical operative intervention and targeted intravenous antibiotics as in our case. Faced with a subacute osteomyelitis, we have to remember that it may mimic bone tumors. We highlight the isolation of Salmonella B in a patient without sickle cell disease

Aims

The aticularis genu (AG) is the least substantial and deepest muscle of the anterior compartment of the thigh and of uncertain significance. The aim of the study was to describe the anatomy of AG in cadaveric specimens, to characterize the relevance of AG in pathological distal femur specimens, and to correlate the anatomy and pathology with preoperative magnetic resonance imaging (MRI) of AG.