Y. Sugioka

Diagnostic criteria of primary osteoporosis

New diagnostic criteria of primary osteoporosis (2000 version) was presented. The basic concepts are as follows. Firstly, estimation of low bone mass should be made by lumbar BMD by DXA. However, when measurement of lumbar BMD is not appropriate due to fracture or deformities of the spine, hip, radial, calcaneal, or metacarpal BMD should be used. X ray picture of the spine should be used when DXA is not available. Secondary, in cases with fragility fractures, or in cases with BMD below 70% of young adult mean, differential diagnosis should be made in order to rule out other diseases with low BMD than primary osteoporosis.

Surgical biomaterials and differential colonization by Staphylococcus epidermidis

The data presented in this communication demonstrate preferential colonization of certain biomaterials by Staphylococcus epidermidis. Using a laminar flow biomaterial colonization chamber and surgical-grade biomaterials (stainless steel, aluminium ceramic, methyl methacrylate and high-density polyethylene), the pattern of colonization was quantitated using plate count techniques and electron microscopy. Under comparable conditions, methyl methacrylate was colonized by S. epidermidis in greater numbers than the other biomaterials. Increased bacterial colonization and slime production on methyl methacrylate was time-dependent and 15 times higher than on stainless steel and aluminium and four times higher than on high-density polyethylene. The data reveal that certain biomaterials may promote infection by favouring colonization by potential pathogens. This variable should be explored extensively in an in vivo setting because of its implication in clinical infections.

Effect of surface roughness of hydroxyapatite—coated titanium on the bone-implant interface shear strength

We have investigated the bone-implant interface shear strength of hydroxyapatite (HA)-coated Ti-6Al-4V (HA-coating A) (roughness average, Ra = 3.4 +/- 0.5 microns) and HA-coated Ti-6Al-4V with a rougher surface (HA-coating B) (Ra = 8.4 +/- 1.8 microns). There was no significant difference between HA-coating A and HA-coating B implants with respect to the bone-implant interface shear strength as determined in push-out tests using the transcortical model in adult dogs. The bone-implant interface shear strength of bead-coated porous Ti-6Al-4V was significantly greater than that of both HA-coating A and HA-coating B implants. The failure site, as determined by scanning electron microscopy, was the coating-substrate interface, not the coating-bone interface. This indicates a need to protect the HA coating from the direct shear forces. HA coating enhances early bone growth into the porous surface of the implant. Long-term fixation should depend on bone anchoring to this porous surface. Hydroxyapatite coatings must be developed which do not obstruct the pores of the surface of the implant.

Standing radiographs cannot determine the correction in high tibial osteotomy

The use of standing radiographs to determine correction angles for high tibial osteotomy is not appropriate because the relative angle of the articular surfaces (condylar-plateau angle) in the weight-bearing knee changes after the osteotomy. This may give unpredictable results postoperatively. We found that the condylar-plateau angle in postoperative standing films is very similar to that seen in non-weight-bearing supine views, and suggest that these latter radiographs be used for pre-operative planning. We describe our early results, using a special osteotomy jig, in 140 knees.

Transtrochanteric valgus osteotomy for the treatment of osteoarthritis of the hip secondary to acetabular dysplasia

Our study describes the mid-term clinical results of the use of transtrochanteric valgus osteotomy (TVO) for the treatment of osteoarthritis of the hip secondary to acetabular dysplasia. The operation included valgus displacement at the level of the lesser trochanter, and lateral displacement of the greater trochanter by inserting a wedge of bone. We reviewed 70 hips. The mean age of the patients at operation was 44 years (14 to 59). Most (90%) had advanced osteoarthritis. The scores for pain and gait had improved significantly at a mean follow-up of 9.4 years. The rate of survival until an endpoint of a further operation during a follow-up of ten years was 82%. The survival rate was 95% in patients with unilateral involvement who were less than 50 years of age at operation. TVO is a useful form of treatment for advanced osteoarthritis of the hip, particularly in young patients with unilateral disease.

Destructive spondylo-arthropathy during long-term haemodialysis

We reviewed 29 patients who had developed destructive arthropathy of the spine during long-term haemodialysis. Their mean age when haemodialysis began was 43.8 years; at diagnosis they had been dialysed for an average of 8.6 years. In 26 patients, the lesions were between C4 and C7; in six they were between L4 and S1, three having lesions in both regions. Sixteen patients had had previous surgery for carpal tunnel syndrome. Spinal surgery was performed in nine patients with satisfactory results in only five. We demonstrated beta-2 microglobulin amyloid deposits in the discs and surrounding ligaments in all biopsied cases. The natural history and management of this condition are not yet clear.

Radial closing wedge osteotomy for Kienbock's disease

Twenty-six patients with Kienböcks disease who were treated with a radial closing wedge osteotomy and then followed for a total of 4 years and 5 months were studied. Their mean age at surgery was 31.7 years. Clinical results were excellent in 8, good in 11, fair in 6, and poor in 1 patient using the Nakamura scoring system. Nineteen (73%) patients had excellent or good results, and 25 (96%) were content with their results. Factors affecting the clinical results included the postoperative Ståhl index and the preoperative radiolunate angle. It was concluded that radial closing wedge osteotomy is an effective procedure for patients with Kienböcks disease but that a flexion deformity of the lunate limits clinical success.

Vascularised fibular graft for congenital pseudarthrosis of the tibia. Long-term results

Five children with congenital pseudarthrosis of the tibia treated by free vascularised fibular grafts were followed up until skeletal maturity. The ipsilateral fibula was used in four cases, the contralateral fibula in one. All our cases achieved bone union, but leg length discrepancy, atrophy of the foot and ankle stiffness were frequent complications, due perhaps to the many previous operations. Vascularised fibular grafting might achieve better results if it were done as the primary procedure.

Inhibition by FK506 of established lesions of collagen-induced arthritis in rats

We investigated the superior poteney of the immunosuppressive agent FK506 on collagen‐induced arthritis in rats. In our initial studies, we demonstrated that only one shot administration of FK506 at a dose of 10 mg/kg on the same day as type II collagen immunization suppressed the incidence of arthritis completely as well as humoral and delayed‐type hypersensitivity (DTH) skin lest responses to type II collagen. Yet no major side effects were observed in the rats treated with such a high dose of FK506. Additional studies demonstrated that pretreatment with FK506 on day — 7 or day — 3 was effective in suppressing the severity of arthritis and immune responses to type II collagen. The immunosuppressive effect of a single high‐dose administration of FK506 continued for at least 1 week in this animal model of arthritis. A single administration of FK506 at a dose of 10 mg/kg on day 12 or 15, after the clinical onset of arthritis, was also effective in suppressing the severity of arthritis and immune response to type II collagen. We conclude that FK506, in this model, possesses an important, curative action when applied therapeutically. The outlook of FK506 treatment in clinical autoimmunity is promising at present.

Macrodactyly in Proteus syndrome.

A case of Proteus syndrome in a 13-year-old boy with macrodactyly, hemihypertrophy, exostosis of the skull, epidermal naevi, palmar and plantar masses, and scoliosis is reported. Macrodactyly involving the left thumb was treated surgically. The usual findings in macrodactyly, hypertrophy of the digital nerves and proliferation of subcutaneous fat, were not observed in this case. Macrodactyly associated with Proteus syndrome should be distinguished from other forms of macrodactyly because of its poor prognosis and high rate of recurrence.