Sung Man Rowe

Osteolysis in Association with a Total Hip Arthroplasty with Ceramic Bearing Surfaces

The results of 103 total hip arthroplasties performed with insertion of a ceramic femoral head and acetabular component in ninety-six patients were reviewed to determine the radiographic prevalence of osteolysis. After a mean duration of follow-up of ninety-two months (range, sixty to 125 months), femoral osteolysis was observed in twenty-three hips (22 per cent), in one of two distinct patterns: linear osteolysis (twelve hips) or scalloping expansile-type osteolysis (eleven hips). The most common locations of osteolysis in the femur were in zones I and VII as described by Gruen et al. Serial radiographs demonstrated that the extent of the osteolysis progressed over time. Osteolysis of the pelvis, noted in forty-nine hips, was always associated with migration of the acetabular socket. No focal osteolysis was observed in association with the stable sockets. Ten patients (ten hips) had a revision because of loosening and migration of the acetabular component. In three of these patients, the femoral stem also was revised. Gross examination revealed evidence of wear of the ceramic bearing surface in all ten patients. Scanning electron microscopy showed cracking and wear marks on the weight-bearing surface. Histological evaluation of the tissue in the periprosthetic membrane demonstrated abundant ceramic wear particles. The interface membrane was composed of a vascularized fibrous connective tissue with macrophages. Ultrastructurally, the macrophages contained numerous phagosomes of various sizes, with electron-dense material within the cytoplasm of the cell. The mean size of the ceramic particles, as determined with scanning electron microscopy, was 0.71 micrometer (range, 0.13 to 7.20 micrometers). This study supports the concept that ceramic wear particles can stimulate a foreign-body response and periprosthetic osteolysis.

The incidence of Perthes’ disease in Korea: A FOCUS ON DIFFERENCES AMONG RACES

The purpose of this study was to determine the annual incidence of Perthes disease in Korea and compare this with other populations. A survey identified all newly diagnosed children with Perthes disease aged 14 years or younger in South Honam, Korea, between January 1999 and December 2001. A total of 84 children were included: 29 in 1999, 28 in 2000 and 27 in 2001. The mean annual incidence was 3.8 per 100 000. This is similar to that reported in other Asian countries, but higher than in black populations and lower than in Caucasians.

Active tuberculosis of the hip treated with early total hip replacement--a report of 3 cases

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Acetabular revision using acetabular roof reinforcement ring with a hook

This study evaluated the clinical and radiographic results of 37 acetabular revisions using an acetabular roof reinforcement ring with a hook (ARRRH). The average age of the patients was 52.4 years, and the mean follow-up period was 4.5 years. The mean Harris hip score had improved from 49 points preoperatively to 87 points at the final follow-up. The bone graft was radiographically incorporated in all cases. The postoperative complications were a hip dislocation in 3 cases, nonunion of the greater trochanter in 1, infection in 1, discomfort at the autograft donor site in 3, and 2 cases of hook failure. An ARRRH combined with a morsellized bone graft is a useful treatment particularly in moderate-to-severe acetabular bone deficiencies.

Fate of the osteochondral fragments in osteochondritis dissecans after Legg-Calvé-Perthes’ disease

The treatment of osteochondritis dissecans after Legg-Calvé-Perthes disease has not been clearly determined. It may be either by simple observation or surgical removal of the osteochondral fragment. We studied the evolution of the lesion in 13 children and reviewed 92 hips reported in the literature. In our patients ten showed a tendency towards spontaneous healing, one required drilling + grafting to obtain fusion, and in two there was separation into the joint. These loose bodies were in the acetabular fossa and caused no symptoms. On reviewing the literature, we found only four cases of hips with loose bodies from osteochondritis dissecans. These were lying in the inferomedial capsule and were also asymptomatic. Treatment of osteochondritis dissecans after Legg-Calvé-Perthes disease should therefore be conservative unless the fragment interferes with the mechanics of the hip.

Deformity of the femoral head following vascular infarct in piglets.

Backgroundu2003In Legg-Calvé-Perthes disease (LCPD), 4 major patterns (coxa plana, coxa magna, coxa vara, subluxation) of the femoral head are commonly observed. However, direct observation of pathological specimens is rarely possible. An animal model of LCPD may clarify the pathogenesis of femoral head deformity. Animals and methodsu2003In 26 piglets, we interrupted the vascular supply to the capital femoral epiphysis by cutting the ligamentum teres and ligating the femoral neck containing the epiphyseal artery. 6–7 piglets in each experimental group were killed at early (2 and 4 weeks: P2 and P4), intermediate (12 weeks: P12), and late (20 weeks: P20) periods. We examined the extracted femoral heads macroscopically and radiographically. Resultsu2003The mean decrease in epiphyseal height was 1.5u2009mm, 4.1u2009mm, 5.0u2009mm, and 7.5u2009mm in P2, P4, P12 and P20, respectively (rs = 0.76, p = 0.002). The mean increase of diameter was 4.1u2009mm, 6.9u2009mm, and 6.8u2009mm in P4, P12 and P20, respectively. Decrease of the articulotrochanteric distance was mild in P2 and P4, and severe in P12 and P20. Subluxation of the femoral head was observed only in P12 and P20 piglets. Interpretationu2003The piglet model of LCPD was useful in the early stage of devascularization for investigation of the developmental pattern of femoral head deformity. However, when the piglets had grown to 20 weeks old or more—that is, to full skeletal maturity—the femoral head and acetabulum showed severe deformities that were most likely caused by heavy body weight.u2003▪

Why does outer joint motion predominate in bipolar hip prosthesis?Experimental and clinical studies

Background Theoretically, the motion of a bipolar hip prosthesis is most likely to occur at the inner joint if the frictional coefficients are equal at both surfaces. However, many studies have suggested that most motion occurs at the outer joint. Material and methods We performed an analysis of motion in a cadaveric bone model and in 50 patients during fluoroscopic examination, to determine how the motion is distributed between the two joints and what factors contribute to this distribution. Results The motion distributions varied widely between the patients. However, there was a relative preponderance (63–90%) of outer motion in all directions of leg movement in addition to a persistent coexistence of motion at both joints in 44 of 50 patients. This preponderance of outer motion was the result of an early impingement of the acetabular cup and structural differences between the two joints. Interpretation An adjustment of the positive eccentricity and a decrease in the frictional torque of the inner joint as a result of better lubrication and smoothness can be expected to improve the motion distribution, thus reducing the amount of acetabular erosion.

Osteochondritis dissecans in Perthes' disease Report of 7 cases

We report 7 cases of osteochondritis dissecans following Perthes disease in 363 hips, i.e., an incidence of 2 percent. Six of the 7 cases belonged to Salter group B (Catterall Groups III-IV), indicating a higher incidence in hips with a worse prognosis. Six cases were asymptomatic and did not require treatment; in 3 of these, there was spontaneous radiographic healing of the lesion.

Free osteochondral fragment caught in the acetabular fossa in the osteochondritis dissecans after Legg-Calvé-Perthes' disease: Report of 2 cases

No Abstract available.