The medial patellofemoral ligament (MPFL) is the main stabilizer of the patella and therefore mostly reconstructed in the surgical correction of patellofemoral dislocation. Various biomechanical and clinical studies have been conducted on MPFL reconstruction, while the patellofemoral contact pressure (PFCP) which is indicated as one of the predictors of retropatellar osteoarthritis was neglected. Therefore, the aim of this study was to investigate how different MPFL reconstruction approaches affect PFCP. After radiographic examination and preparation six human cadaveric knee joints (52.1 ± 8.4yrs) were placed in a 6-DOF knee simulator. Three flexion-extension cycles (0–90°) were applied, while the extensor muscles (175N) and an axial joint load (200N) were simulated. PFCP was measured in knee flexion of 0°, 30° and 90° using a calibrated pressure measurement system (K-Scan, Tekscan Inc., USA). The following MPFL conditions were examined: native (Pnat), anatomical reconstruction (Pa), proximal and distal patellar single-bundle reconstruction (Pp, Pd), proximal and ventral femoral reconstruction (Fp, Fv). The cohesive gracillis graft of each knee was used for MPFL reconstruction. Further, the effect of three different graft pre-tensioning levels (2N, 10N, 20N) on the PFCP were compared. Nonparametric statistical analysis was performed using SPSS (IBM Inc., USA).Introduction
Material & Methods
Reduction therapy in developmental dysplasia of the hip (DDH) is initialized in the newborn period. Harness treatment is continued until normal ultrasound-values are reached. Above the age of one year the assessment of DDH relies mainly on interpretation of plain radiographs of the pelvis. In order to rule out residual dysplasia after ultrasound controlled treatment radiological control is advised to the time children start walking. The purpose of this study is to evaluate the early radiological outcome after ultrasound controlled treatment of DDH and to examine whether there is a correlation between the initial severitiy of DDH, measured by ultrasound, and the severity of residual DDH on the radiograph at the time of the first follow-up. A. p. pelvic radiographs of 90 children (72 girls, 18 boys, 180 hips) with DDH (29 unilateral, 61 bilateral) were reviewed retrospectively. To the beginning of the ultrasound surveilled therapy (mean age 7,2 weeks) the morphologic findings were staged according to the Graf classification. Ultrasound surveilled abduction treatment was continued until normal ultrasound findings were reached. To the time children started walking (mean age 14,8 months) an a. p. radiograph of the pelvis was performed. The acetabular index (AI) was measured and classified according to the normal values of the hip joint described by Tönnis. The initial ultrasound findings expressed by the Graf classification were compared with the AI in the radiographic follow-up and Tönnis’ normal values. To simplify matters the 180 Graf-classified hips were distributed into 4 categories: Graf Ia/b=category 1, Graf IIa-D=category 2, Graf IIIa/b=category 3, Graf IV=category 4. The initially normal contralateral hips in ultrasound (n=29, category 1) presented in 37,9% a normal AI, in 41,4% with a mild dysplasia (between 1SD and 2SD) and in 20,7% with a severe dysplasia (beyond 2SD). The Graf type IIa-D hips (n=81, category 2) presented in 37% a normal AI, 32,1% showed a mild dysplasia and 30,9% a severe dysplasia. The Graf type III a/b hips (n=60, category 3) showed 35%, 30% and 35%, Graf type IV hips (n=10, category 4) 60%, 30% and 10%, respectively. The mean AI in all four categories differed only marginally. In our setting of patients different conclusions can be drawn:
Even after successful ultrasound guided therapy with a sonographically normal hip at the time bracing is finished there is a risk for residual dysplasia. Therefore radiological follow-up of every once treated hip is necessary. To reduce the number of radiographs the time for the first radiographic follow up may be delayed to the age of two. We only see a minimal risk to miss a dislocated hip in time. In very rare cases the indication for an acetabuloplasty is generally seen before the age of two, in our patient population we saw no immediate indication for surgery.
The non-invasive diagnosis of musculoskeletal infections remains a challenge. Recent studies have indicated that fluorine-18 fluorodeoxyglucosepositron emission tomography (FDG-PET) is a highly accurate imaging technique in selected patient groups with infected total hip replacement. The present study analyses the diagnostic accuracy in a consecutive series of patients with suspected musculoskeletal infections.
