A Trabecular Metal Modular Acetabular System (Zimmer, Warsaw, Indiana, USA) is a peripheral rim expansion (elliptical) cup, i.e. a non-hemispherical cup. Radiologically a non-hemispherical cup may be deferent from other conventional hemispherical cups. We reviewed radiological findings of a Trabecular Metal Modular Acetabular System chronologically. Twenty six patients with osteoarthritis underwent primary total hip arthroplasty (THA) using a Trabecular Metal Modular Acetabular System from 2011 to April 2013. Twenty five patients (follow-up rate: 96.2%) 31 hips could be followed-up over a year were registered. In common, the diameter of every femoral head was 32 mm. We planned the acetabular cup inclination angle to be 45-degree, the cup coverage with host-bone (cup-CE angle) to be over 10-degree, and high hip center was allowed up to 20mm. In case of the cup-CE angle under 10-degree, an acetabular cup was placed medially using Dorr's medial protrusio technique. We established the medial protrusion angle indicating the degree of medial protrusion of an acetabular cup over the pelvic internal wall. The medial protrusion angle was defined by the center point of THA (C) and the 2 cross-points (X1, X2) which the outline of an acetabular cup crosses the Kohler's line (Figure 1). The cup anteversion angle was measured by the method of Lewinnek, and the cup fixation was evaluated according to the Tompkin's classification.Purpose
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Between 1974 and 1998, 34 patients with primary bone tumors and 28 with soft tissue tumors, all located in the foot, were surgically treated at our institutions. Of the 34 patients with a bone tumor, 27 (79%) had chondrogenic tumors: exostoses, 17; enchondromas, 7; benign chondroblastomas, 2 and chondrosarcoma, 1. This chondrosarcoma was misdiagnosed as a benign chondroblastoma at the initial biopsy. Five months after the initial curettage and bone grrafting, the tumor was recurred as a chondrosarcoma. This patient died with pulmonary metastasis another five months after the below the knee (BK) amputation. The differential diagnosis between benign chondrogenic tumors and low grade chondrosarcoma is very difficult as proposed by Mirra. Whereas the malignant tumor is very rare in the foot, the diagnosis of chondrogenic tumor should be made carefully. Of the 28 soft tissue tumors, diagnoses were giant cell tumor of tendon sheath or pigmented villonodular synovitis, 8; angioleiomyoma, 4; ganglion, 4; hemangioma, 2; miscellaneous benign tumors, 7 and soft tissue sarcomas (STS), 3. All patients with a STS were treated by a BK amputation, a partial foot amputation or a marginal resection, and died with pulmonary metastasis. However the function of the operated limb and the emotional acceptance were better in a patient with the less abrasion surgery.
