Introduction: The purpose of this study was to investigate the effects of combination treatments with anticoagulant (warfarin) and a lipid-lowering agent (probucol) on the prevention of steroid-associated osteonecrosis (ON) in rabbits.

Materials and Methods: Male adult Japanese white rabbits were intramuscularly injected once with 20mg/kg body weight of methylprednisolone acetate into the right gluteus medius muscle. These rabbits were divided into three groups: a warfarin plus probucol treatment group (WP Group, n=25), a probucol treatment group (PR Group, n=30), and a non-prophylactic treatment group (NP Group, n=20). Two weeks after the cortico-steroid injection, both femora and humeri were histopathologically examined for the presence of ON, and the sizes of bone marrow fat cells were morphologically examined.

Results: The incidence of ON in the WP Group (5%) was significantly lower than that in the NP Group (70%) (p < 0.0001). The incidence of ON in the PR Group (37%) was significantly lower than that in the NP Group (p < 0.05), but it was significantly higher than that in the WP Group (p < 0.01). The mean size of the bone marrow fat cells was significantly smaller in the WP Group (53.5 ± 4.1μm) than that in the NP Group (60.0 ± 4.0μm) (p < 0.0001). There were no significant differences in the size of bone marrow fat cells between the WP and the PR Groups (52.0 ± 5.0μm).

Discussion: This study experimentally confirmed that anticoagulant plus lipid-lowering agent treatment has a preventative effect on steroid-associated ON in rabbits.

Introduction: When osteonecrosis is located in the medial portion of the femoral head, transtrochanteric curved varus osteotomy (varus), in which the lateral intact area is transposed to the weight-bearing portion, is indicated. The purpose of this study was to evaluate the clinical outcomes of this procedure.

Materials and Methods: Cases consisted of 60 hips in 52 patients with osteonecrosis of the femoral head who had a varus osteotomy from 1981 to 1998. Fifty-five hips out of 60 were followed (follow-up rate: 92%; 5 hips dropped out). The underlying associated factors were alcohol (5), trauma (2), and corticosteroids (40); 8 hips were from patients without a known factor (idiopathic). Nineteen were male and 36 were female. The average age was 34 years at the time of surgery. Forty-three hips were classified as ARCO Stage III-A, 11 in Stage III-B, and 1 in Stage IV.

Results: The average follow-up was 8.1 years (range, 0.8 to 20 years). The average preoperative Harris Hip Score of 51 points improved to an average of 81 at the latest follow-up. Radiographically, osteonecrosis in 46 hips (84%) healed or had no progression of collapse. Nine hips (16%) showed osteoarthritic changes, including progression of collapse, in which 4 cases had undergone conversion to THA. The post-operative intact area ratio in these 4 cases was 16%, while that in the other 51 cases was 70% (p< 0.005).

Discussion: When the intact area remains at the lateral portion of the femoral head, varus osteotomy is useful not only for healing of the necrotic lesion but also for the prevention of osteoarthritis. If the intact area ratio is over 34 % with hip abduction, varus osteotomy is indicated.

Purposes: To evaluate the validity of pedicle screw fixation in 20 patients with toracolumbar spine infections.

Methods and Materials: There were seven tuberculous and thirteen pyogenic infection, eight had thoracic and 12 had lumbar lesion. The indications for surgical treatment were; progressive bone destruction, mal-alignment or neurological deficit. On nine cases, we did two-step operation, which was bone graft from anterior and pedicle screw fixation from posterior. On 11 cases, we did debridement, interbody graft and the pedicle screw fixation from posterior simultaneously. We examined the outcomes of the infection, symptoms including neurological deficit and the graft bones postoperatively with follow-up period of 25 months in the average. We also examined changes of alignment after surgery and surgical complications as well to evaluate the validity of the surgery.

Results: Fusion of graft were confirmed in all cases within seven and half months in the average. Clinically, all of 14 patients who had had paraparesis gained neurological recovery of one or two steps of Frankel’s criteria after the surgery. Complications were, fracture of graft, fracture of vertebral body, screw loosening with alignment deterioration and recurrence of infection in one case each.

Summary: Pedicle screw fixation revealed a usefulness in surgical treatment of spine infection.

We undertook 114 arthroscopic meniscal repairs in 111 patients and subsequently carried out second-look arthroscopy to confirm meniscal healing at a mean of 13 months after repair. Stable healing at the repaired site was seen in 90. Of these, however, 13 had another arthroscopy later for a further tear. The mean period between the repair and the observation of a repeat tear was 48 months. Of the 13 patients, 11 had returned to high activity levels (International Knee Documentation Committee level I or II) after the repair.

An attempt should be made to preserve meniscal function by repairing tears, but even after arthroscopic confirmation of stable healing repaired menisci may tear again. The long-term rate of healing may not be as high as is currently reported. Second-look arthroscopy cannot predict late meniscal failure and may not be justified as a method of assessment for meniscal healing. Young patients engaged in arduous sporting activities should be reviewed regularly even after arthroscopic confirmation of healing.

We treated 75 patients with benign bone tumours by curettage and filling the defect with calcium hydroxyapatite (HA). There were 28 women and 47 men with a mean age of 27.7 years (3 to 80). The mean follow-up was for 41.3 months. Postoperative radiological assessment revealed that the implanted HA was well incorporated into the surrounding host bone in all patients. Two patients suffered fractures in the postoperative period. Two patients complained of pain associated with HA in the soft tissues, but this diminished within six months. No patient had local pain at the final follow-up. Recurrence of the tumour was seen in three cases. Histopathological study of the implanted area showed removal of the HA by histiocytes and multinucleated giant cells, and the formation of much appositional bone. We conclude that HA is an excellent bone-graft substitute in surgery for benign bone tumours.

We have studied the correlation between the prevention of progressive collapse and the ratio of the intact articular surface of the femoral head, after transtrochanteric rotational osteotomy for osteonecrosis. We used probit analysis on 125 hips in order to assess the ratio necessary to prevent progressive radiological collapse over a ten-year period. The results show that a minimum postoperative intact ratio of 34% was required. This critical ratio may be useful for surgical planning and in assessing the natural history of the condition.

In about 50% of cases, osteonecrosis of the femoral head is known to occupy more than one site. There is controversy as to whether a single focus may increase in size. We have reviewed 606 consecutive femoral heads which had been surgically removed for osteonecrosis. Extension of osteonecrosis was observed in only two (0.3%) and was confirmed histopathologically by the enlargement of the necrotic segment beyond the repair zone formed for the primary necrosis into the adjacent, previously uninvolved bone. In both cases, the necrotic regions were wedge-shaped and occupied over 80% of the femoral head.

It appears that an increase in size is extremely rare and that osteonecrosis is due to a single event. Our findings may be of value in assessing the use of joint-salvage procedures for osteonecrosis of the femoral head.

Superior labral tears of the shoulder involve the biceps tendon and labrum complex which may be detached, displaced inferiorly, and interposed between the glenoid and the humeral head. We have treated ten young athletes with painful shoulders due to this lesion by arthroscopic stapling. Arthroscopy at the time of staple removal, after three to six months, showed that all the lesions had been stabilised. Clinical review at over 24 months showed an excellent or good result in 80%. The two relative failures were due in one to residual subacromial bursitis, and the other to multidirectional shoulder instability. Arthroscopic stapling can restore the shoulder anatomy, and it is recommended for active adolescent athletes with this lesion.

Excision of the lunate was performed for 18 patients with Kienbock's disease; 14 were followed up for an average of almost 12 years. Carpal collapse progressed with time, but rearrangement of the remaining carpal bones preserved a satisfactory range of movement and grip strength. Degenerative changes were not severe. All the patients had relief of pain, were able to carry out their normal activities, and all but two could perform strenuous activities.