Early functional recovery after two-stage surgery with an allogenic bone graft for baseplate loosening in reverse shoulder arthroplasty: a case report.

OBJECTIVES: Reverse shoulder arthroplasty (RSA) for cuff tear arthropathy results in good shoulder function. However, RSA is associated with several complications, including infection, dislocation of the shoulder joint, implant loosening, and axillary nerve palsy. Several problems may also occur on the glenoid side, including bone defects of the glenoid, baseplate loosening, and displacement of the sphere. Herein, we report a 79-year-old man who obtained early functional recovery following a two-stage operation with an allogenic bone graft to treat baseplate loosening and a glenoid bone defect after RSA. CASE REPORT: The patient presented with pain during motion and limited active shoulder joint movement 5 weeks after undergoing RSA for cuff tear arthropathy. CT revealed baseplate loosening and a glenoid bone defect; these complications were treated via a two-stage operation. The first stage comprised the removal of all implants and the grafting of allogenic bone from the femoral head into the glenoid defect. Six months later, CT confirmed complete union of the grafted bone and glenoid. The second stage comprised the re-insertion of all implants. Two months after the last operation, the active shoulder range of motion of the affected side was almost identical to that of the contralateral side. CONCLUSION: Good early functional recovery was obtained using a two-stage operation for baseplate loosening after RSA. Allogenic bone grafting was effective in the reconstruction of the glenoid defect.

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

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.

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.