Direct anterior approach (DAA) is one of the best way to the hip joint for prevention of post-operative dislocation. We have applied this method as minimum invasive surgery (MIS) to more than two hundred developmental dysplastic hip of Japanese patients in total hip arthroplasty (THA) and there is no post-operative dislocation within three years of last observation carried forward (LOCF). The reason of this benefit is derived from the accuracy of cup positioning and keeping good muscle balance. But the learning curve is very important and some technical pitfalls are there in this approach. We have chosen thirty four patients that the duration of operating time more than one and half hours and loss of blood more than five hundred gram in hour series. The most important factors of the difficulties are the combinations of shortening of femoral neck, especially Perthes like deformity of developmental deformities of the hip joint (DDH) and widening of pelvic bone for the reason of insufficiency working spaces and the difficulties of broaching insertion (8/34). The second factor is the contracture of hip and knee joints combinations for the difficulties of lift up the proximal femur as broaching stem (3/34). The obesity, Body Mass Index (BMI) above thirty is not the reason of difficulties of women in our series. DAA can be extended to Smith-Petersen approach and very useful technique for primary THA in Japanese dysplastic hip patients.

Introduction: In general a loose-balanced total knee arthroplasty (TKA) are believed to gain good postoperative range of motion (ROM), however, too much laxity is thought to be a cause for persistent pain and catastrophic long-term results.

Materials and methods: We measured the antero-posterior and medio-lateral laxity to evaluate the influence of stability after cruciate-retaining TKA on ROM, pain score in Knee Society score and Functional score at 4–7 years after the operation. Twenty-one knees in 15 patients with an average age of 68 years (range, 58–78) who had a PCL retaining TKA for osteoarthrosis were examined (YS-4, 16 knees; AGC-S, 5 knees). There were 12 women and 3 men. Anteroposterior laxity was examined using a KT 2000 arthrometer at 30-degree knee flexion. Mediolateral laxity was examined at full extension with manual stress x-rays.

Results: Average ROM was 112 degrees (range, 90–140 degrees), antero-posterior laxity was 9.7 mm (range, 2–27 mm) and mediolateral laxity was 10.6 degrees (range, 5–22 degrees). Knee Society pain score was 47 (range, 10–50) and Functional score was 82 (range, 40–100). No significant difference in ROM and clinical scores were noted between the lax and the stable knees. Correlations between ROM and anteroposterior or medio-lateral laxity were not significant (P = 0.55, P = 0.05, respectively; Spearman’s correlation efficient).

Discussion and conclusion: A loose-balanced TKA did not gain good post-operative ROM. No parameters suggested that lax knees got better flexion angle, worse pain score and functional score than stable knees.

Between 1989 and 1993, 158 patients with a total of 187 damaged knees underwent TKA using AGC-S prosthesis (Biomet). Of these patients, six required revision surgeries due to metallosis. The average period from the first operation to the revision was 68.0 months (range: 41–97 months). In all six cases, the plain X-rays taken immediately before reoperation, showed sinking of the tibial component. The withdrawn implants showed severe abrasion of the polyethylene used in the posteromedial area. The percent share of the tibial component averaged 90.3% (range: 85.3–93.5%) on the anteroposterior view, and on the lateral view averaged 83.1% (range:76.9–94.0%). The tibial components used for AGC-S type TKA can be characterized by the presence of a rim. In some cases, however, the rim cannot be placed on the tibial cortex, and this obliges the surgeon to select smaller components, resulting in a smaller percent share of the tibial component. The tibial component can sink in such cases. The sinking of the tibial component probably leads to malalignment and joint instability. Furthermore the insert with a flat surface was likely to induce articular instability, thus enhancing the abrasion of the polyeth

Although bone loss and ligamentous instability are usually indications for the use of constraining prostheses in revision total knee arthroplasty (TKA), several reports have documented a high rate of failure with these prostheses. We therefore tried using the cruciate retaining augmentable type prosthesis (NexGen CRA) if a good intraoperative ligamentous balance could be obtained with revision TKA.

CRA was used on nine knees of seven patients with an average age of 71.7 years. The follow-up lasted for an average of 1.6 years. Clinical evaluation consisted of instability ratings, knee score, range of motion and %MA (mechanical axis) as an index of the alignment. These patients showed improvement varus instability from a mean of 7.0° preoperatively to a mean of 1.5° postoperatively, and in valgus instability from 5.3° to 1.3°.

The knee score was significantly improved from 41 to 81, but the %MA resulted in an unsatisfactory improvement from −8.8% to 34.0%. The femoral anatomical-mechanical angle (FAMA) was measured as a parameter of bowing deformity of the femur, and the knees were divided into two groups, the bowing group consisting of the knees with an FMA of more than 8° (n=6, average 9.0°), the normal group of knees with an FAMA of less than 7° in FAMA (n=3, average 6.7°). The postoperative %MA showed a mean value of 40.9% for the normal group, and 30.6% in the bowing group. These results demonstrated that the discrepancy between FAMA for the bowing group(=9.0°) and the valgus angle of the stem of the femoral component (6.0°) was the cause of the malalignment in the bowing group. These clinical results suggest that the cruciate retaining augmentable type prosthesis can be used successfully for selected revision cases, but that malalignment in knees with bowed femora may remain a problem.

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.

Our purpose is to use radiographs to compare callus formation with two types of intramedullary nailing for femoral shaft fractures: reamed interlocking (IL) and Ender nails.

Femoral shaft type A fractures according to AO classification were studied.

From 1991 to 1995, 27 patients with 27 fractures were treated with reamed IL nailing and 79 patients with 81 fractures were treated with Ender nailing. IL group included with an average of 22 (range, 16–28) years, and the Ender group included with an average of 28 (range, 15–72) years.

Patients had been followed for an average of 1.8 (range, 1–2.8) years after surgery. In all cases of IL group, the femoral canal was reamed. For type A3 fractures, an interlocking screw was inserted only at the distal site. For type A1 and A2 fractures, both proximal and distal locking screws were placed. In the Ender nailing cases, 3 to 5 Ender nails were inserted from medial or lateral side of the supracondylar or intertrochanteric regions of the femur as was dictated by the fracture site. All of these fractures were reduced by a closed technique. The measurement of postoperative callus area was calculated from the maximum cross-sectional area on the anteroposterior and lateral radiographs.

Fracture healing was successful in all patients. On the radiograph, the callus for the IL group appeared at a mean of 3.9 weeks after surgery, and at a mean of 2.8 weeks for the Ender group. In the IL and Ender groups, fracture healing was noted at a mean of 3.4 and 2.0 months, respectively. The mean area of callus formation in the IL and Ender nailing was 439.5mm2 and 699.4 mm2, respectively. To compare the two groups by using a Mann-Whitney U test, the significant differences were seen in the callus appearance period (p< 0.05) and in the callus area (p< 0.01).

Dynamization at the fracture site is reported to increase external callus formation.

Our results indicate that the elasticity of the fixation obtained with Ender nailing promotes callus formation.