Toshiyuki Ishiko

Total hip arthroplasty: the relationship between posterolateral reconstruction, abductor muscle strength, and femoral offset.

Purpose. To evaluate the relationship between posterolateral reconstruction, abductor muscle strength, and femoral offset following total hip arthroplasty. Methods. Of 28 patients (56 limbs) we assessed, 12 underwent posterolateral reconstruction (reconstruction group) and 16 did not (non-reconstruction group). Isometric abductor muscle strength was measured with a handheld dynamometer. Each patients muscle strength was converted into a force to body weight ratio, and this ratio was used in the comparisons. Results. The reconstruction group showed a higher value in abductor muscle strength than the non-reconstruction group (p<0.05). Significant correlation between abductor muscle strength and femoral offset was found in the reconstruction group (p=0.016; r=0.674). Conclusion. Posterolateral reconstruction and appropriate reconstruction of femoral offset following total hip arthroplasty are important to improve the abductor muscle strength.

Arthroscopic Removal of an Intra-Articular Osteoid Osteoma of the Radial Styloid

We describe a case of intra-articular osteoid osteoma arising in the radial styloid of a 21-year-old man. Plain radiographs were not diagnostic, but computed tomography, gadolinium-enhanced magnetic resonance imaging, and bone scintigraphy suggested the possibility of an osteoid osteoma. We arthroscopically removed the lesion; histological examination confirmed the diagnosis. The patients symptoms disappeared immediately after surgery.

Arthroscopic surgery for synovial chondromatosis of the hip: a report of two cases

AbstractWe have used arthroscopy in the treatment of synovial chondromatosis of the hip joint. Two patients complained of pain of the hip joint that was aggravated by weight bearing. On admission, range of motion of the affected hip joints was slightly restricted. At hip arthroscopy, osteochondral loose bodies were removed from the joint and partial synovectomy was performed. Histologic examination revealed synovial chondromatosis. Pain relief was obtained in both patients postoperatively.

Regional difference of tensile properties of the human acetabular labrum in various hip disorders

Background Most acetabular labral tears have been shown to occur in the anterosuperior quadrant of the acetabulum. This region may represent a weak area that predisposes the labrum to detachments later in age. Labral detachments may be potentiated by acetabular dysplasia as well. We examined tensile properties and histological appearance of human acetabular labra for regional differences. Methods Human acetabular labra were harvested from 45 patients who underwent total hip arthroplasty for the treatment of secondary osteoarthritis caused by developmental dysplasia of the hip (DDH), primary osteoarthritis or idiopathic necrosis of the femoral head. Thereafter, the tensile properties of the human acetabular labra were investigated using a uniaxial tension testing apparatus. In addition, the pathological findings of the harvested labra were observed. Results For all specimens, the mean tensile stresses at failure of the anterosuperior and posteroinferior labra were 4.0 ± 1.6 MPa and 4.6 ± 1.8 MPa, the mean strains were 31.9 ± 28.3% and 22.3 ± 5.4%, and the mean tensile moduli were 38.3 ± 16.9 MPa and 47.3 ± 22.2 MPa, respectively. No significant difference was found between the tensile properties of the anterosuperior and posteroinferior labra. Moreover, no significant differences were found among the tensile properties in the three groups. However, a negative correlation was found between the tensile stress at failure of the anterosuperior labrum and age in DDH group (P = 0.004, R2 = 0.392). In addition, the pathological findings revealed that the degeneration of the anterosuperior labrum was more severe than that of the posteroinferior labrum in the DDH group. Our results further revealed that the tensile stress at failure of the anterosuperior or posteroinferior labrum was frailer than that of the posterosuperior labrum in a similar group in a previous study. Conclusions The degenerative changes observed in the anterosuperior labrum may influence the occurrence of labral tears in DDH.