We followed 66 total hip arthroplasties using a cement-less Omniflex femoral component with different surface morphology in 51 patients for a mean of 98 months (72 to 138). There were 57 women and nine men, and the mean age of the patient at the time of operation was 55.4 years (39 to 70). Preoperative diagnosis was osteoarthritis secondary to congenital hip dislocation and dysplasia in 64 hips, rheumatoid arthritis in two hips. This series was divided into three groups according to the extent of surface treatment in the proximal part of the femoral component. A circumferential Hydroxyapatite or titanium plasma-spray coated Omniflex stem was used in 33 hips (Group A). A patchy titanium-beads coated stem and a smooth surfaced stem of the same design were used in 25 hips (Group B) and eight hips (Group C), respectively.

Clinically, the mean Harris Hip Score was 54 points preoperatively, which improved to 89 points at the latest follow-up. Incidence of thigh pain was the lowest in Group A ( 6%) in comparison with in Group B (28%) and Group C (25%). Radiographically, the aseptic loosening rate of the femoral component was none in Group A, 16% in Group B and 75% in Group C. Incidence of femoral osteolysis was almost the same rate among the three groups; 38% in Group A, 40% in Group B, and 50% in Group C. However only in Group A, no Osteolysis was found distal to the lesser trochanter level. The femoral revision was performed in two hips of Group C. This study elucidated that the extent of surface treatment would be one of the important factors to influence the stem stability and the occurence of femoral osteolysis.

Fit with the proximal femoral cortices is critical to the success of cementless femoral stems in total hip arthroplasty. Conventional femoral stems are often designed from the average geometry of the normal femora. Hip disease in Japan, however are predominantly associated with Osteoarthritis secondary to congenital hip dislocation or sublux-ation of the hip. We developed a new model of proximal fitting cementless total hip stem, the so-called FMS (for Fukui Medical School) stem, based on the endosteal geometry of Japanese proximal femoral canal with developmental dysplasia of the hip. The proximal third surface of this stem model was circumferentially hydroxyapatite-coated.

One hundred-two hips in 85 patients underwent cement-less total hip arthroplasty with the new stems were studied with a minimum follow-up period of two years. There were 78 women and 8 men, and the mean age of the patient at the time of operation was 56.4 years. Preoperative diagnosis was developmental dysplasia of the hip in 94 hips, osteonecrosis in 6 hips and rheumatoid arthritis in 2 hips. The mean follow-up period was 43 months (24 to 74). Clinically, the mean Harris Hip Score was 48 points preoperatively, which improved to 92 points at the latest follow-up. Thigh pain was present in two hips (2%) at the latest follow-up although in six hips (6%) in the study group at one-year follow-up. Radiographically, according to Engh’s criteria, spot welds associated with osseointegration were observed around the inferior border of the proximal coating in all hips. We have observed no loosening or failure of the stems at the latest follow-up. Our results indicate that the new model of proximal fitting cementless fem

The purpose of this study is to call attention to the diagnosis of spinal cyst caused by lumbar disc herniation. Reviewing a total of 11 cases of lumbar spinal cyst that have been encountered in our spinal practice, we propose our views concerning the pathology of this lesion.

The clinical findings of lumbar spinal cyst are identical to those in acute disc herniation such as low back pain and radiculopathy. The characteristics of imaging study are as follows; The magnetic resonance imaging (MRI) demonstrates a relatively large, rounded mass postero-laterally to the vertebral body. These lesions are isointense relative to the intervertebral disc on T1-weighted images and homogeneously hyperintense on T2. A gadolinium -DTPA-enhanced MRI shows a rim-enhancing lesion. A discogram reveals leakage of the contrast medium into the mass.

The operative findings demonstrated encapsulated soft tissue masses which contained bloody fluid and small fragments of herniated disc tissue. The pathologic examinations revealed fibrous tissue with hemosiderin deposit in cyst wall and degenerative disc materials with inflammatory cell infiltration.

This type of lumbar spinal cyst has been recognized as spinal epidural hematoma in recent years. Wiltse suggested that epidural hematoma may result from tearing of fragile epidural veins due to acute disc disruption. However, MRI characteristics of hematoma are not identical with those with lumbar spinal cyst. It is more likely that the lesions showing the pattern of changes are herniated disc tissue accompanied by hemorrhage and inflammation. If hernial tissue is covered with some membranous susbtance, formation of cystic lesions is understandable. Hence, we hypothesize that lesions, in which lysis liquefaction and absorption of the herniated disc tissue associated with inflammatory response have progressed, and the herniated disc tissue has completely disappeared, may be filled solely with bloody fluid, showing an appearance like cysts.

We treated 31 consecutive patients of mean age 43 years (22 to 59) with severe osteoarthritis of the hip secondary to dysplasia by valgus-extension osteotomy. The clinical results were analysed for factors which may have affected the outcome. The procedure was carried out only on one side and was combined with a Chiari pelvic osteotomy in four patients. The angle of valgus was between 30 and 40° with 10 to 20° of extension. The mean follow-up was 15 years (12 to 18).

Clinical evaluation using Charnley’s modification of the system of Merle d’Aubigné and Postel showed that the mean score for pain had improved from 2.3 before operation to 4.2 at 15 years, and function from 2.3 to 4.2. Range of movement had decreased from 4.2 to 3.5. Fifteen patients (48.4%) had a pain score of 5 or 6 and were evaluated as satisfactory. Kaplan-Meier survivorship analysis showed a survival rate of 51% at 15 years after operation. Two preoperative factors had a significant positive correlation with the radiological results, namely the thickness of the capital drop osteophyte and the length of the roof osteophyte.

We suggest that this procedure is effective for advanced osteoarthritis in the dysplastic hip in young and active patients if these factors are satisfactory on the preoperative radiographs.

We performed Charnley total hip arthroplasties on 64 patients (71 hips) between 1976 and 1984 for moderate congenital acetabular dysplasia in which a superolateral cement thickness of less than 20 mm was expected when the cup was placed in the true acetabulum at an angle of 45°. Of these, 59 hips were examined 10 to 17 years after operation; 37 (group A) had been operated on between 1976 and 1982 using Charnley’s original technique of cementing the acetabulum and 22 (group B) between 1983 and 1984 using more modern techniques.

In group A, aseptic loosening of the socket was observed in ten hips (27.0%) and the 17-year survival rate was 81.5%. In group B, loosening was noted in only one socket (4.5%) and the 13-year survival rate was 100%. The improved techniques produced significantly better long-term results in fixation of the cup in dysplastic hips without bone grafting.

We performed total hip replacement on 25 congenitally dislocated hips using corticocancellous bone from the femoral neck as a bone graft to reconstruct the deficient acetabulum. Two patients (two hips) died less than five years after surgery and three hips developed deep infection. We reviewed the remaining 20 hips at an average interval of 8.4 years (5.2 to 12.9). Their functional scores (modified Merle d'Aubigne and Postel) averaged 5.7 for pain, 5.1 for walking ability, and 4.2 for range of motion. Radiographs showed union and remodelling of the grafted bone in every case. There were radiological signs of aseptic loosening in three sockets (15%) without collapse of the grafted bone. None of the femoral stems was loose. No revision operation has been performed. Our results confirm the usefulness in the long term of femoral autografts for severe acetabular deficiency.