Analysis of the Postoperative Displacement of Trochanteric Fractures on Lateral View Radiographs

Achieving sufficient support of the anterior cortex of the femoral neck is a fundamental goal of the reduction of trochanteric fractures. However, anterior-cortex support is often lost after the fracture reduction. Our aim was to analyze factors contributing to the postoperative displacement of an acceptably reduced trochanteric fracture. The cases of 40 patients with a post-reduction Ikuta subtype N fracture alignment were reviewed. All fractures were fixed with 135° free-sliding plates. On postoperative day 14, patients were classified into two groups: those with retention of the Ikuta subtype N alignment, and those with progression to Ikuta subtype P alignment. The clinical and radiological factors were evaluated between the groups. In addition, to define one of the factors, i.e., the postoperative rotational displacement between the proximal and distal fragments, the relationship between radiographic findings and computed tomography image measurements was assessed in 15 of the 40 patients. Angulation at the fracture site on lateral view radiographs was defined as postoperative rotational displacement, and unstable trochanteric fractures and postoperative rotational displacement were identified as significant risk factors for the postoperative displacement. Therefore, cautious and careful follow-up is warranted for patients with unstable trochanteric fractures or fractures having rotational displacement

Mechanical simulation study of postoperative displacement of trochanteric fractures using the finite element method

Abstract Background Femoral trochanteric fractures are common among older adults. In the reduction of trochanteric fractures, acquiring the support of the anterior cortex at the fracture site on lateral view immediately after surgery is important. However, even if the cortical support is acquired, postoperative displacement due to the loss of this support often occurs. This study aimed to investigate local stress distribution in several trochanteric fracture models and to evaluate risk factors for postoperative displacement using the finite element (FE) method. Methods Displaced two-fragment fracture models with an angulation deformity at the fracture site and a non-displaced two-fragment fracture model were constructed. The models with an angulation deformity were of two types, one with the proximal fragment directed backward (type A) and the other with the proximal fragment rotated forward from the femoral neck axis (type B). Thereafter, FE models of the femur and a sliding hip screw mounted on a 135° three-hole side-plate were constructed. A 2010-N load was applied to the femoral head, and a 1086-N load was applied to the greater trochanter. Under this condition, the maximum value of the von Mises stress distribution and the amount of displacement of the femoral head vertex in the distal direction were investigated. Results A larger maximum stress value at the medial femoral neck cortex and a higher amount of displacement in the distal direction were particularly recognized in type A models. These results indicate that microstructural damage was larger in type A models and that type A fracture alignment may be particularly related to fracture collapse and subsequent postoperative displacement. Conclusion Even if support of the anterior cortex at the fracture site on lateral view is acquired immediately after surgery, caution is necessary for cases in which the proximal fragment is directed backward in the postoperative displacement from the viewpoint of the biomechanics of the FE method

Correlation between ultrasonographic findings and symptoms of knee osteoarthritis

OBJECTIVES: Knee osteoarthritis (OA) is mainly diagnosed by clinical and radiographic findings. The aim of this study was to evaluate the correlation between ultrasonography (US) findings during flexion and knee loading and symptoms of knee OA. METHODS: We studied 33 knees with OA in 21 patients. Using US, the medial meniscal protrusion was measured at the midpoint of the medial joint space with the patient standing and the knee in maximum extension and flexion. With the knee in extension, the thickness of the synovial membrane at the suprapatellar area and the size of the osteophytes at the medial joint space were measured. Radiography was performed to determine the Kellgren-Lawrence (K-L) scores. The correlations between US findings and the visual analog scale (VAS) score, Japanese Knee Osteoarthritis Measure (JKOM) score, K-L score, and range of motion (ROM) were analyzed. RESULTS: Medial meniscal protrusion was significantly correlated with K-L score and ROM limitation. Synovial membrane thickness was also significantly correlated with the total JKOM and usual activity scores. There was no correlation between the VAS scores and US findings. Multigroup comparisons of the patients’ positions during US did not reveal significant intergroup differences. CONCLUSIONS: US was able to detect a change in medial meniscal protrusion during knee flexion and loading. Although medial meniscal protrusion was not correlated with pain, it was related to structural changes of the knee, similar to radiographic findings. Synovial membrane thickness detected by US correlated with pain and a disturbance in the usual activity of patients with OA