Jae Yoon Chung

Femoral neuropathy caused by enlarged iliopsoas bursa associated with osteonecrosis of femoral head--a case report

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Clinical and radiographic outcome of femoral head fractures: 30 patients followed for 3-10 years

The aim of this study was to evaluate the outcome of 30 femoral head fractures. We modified Pipkins classification into 4 types: I (5 cases) small fracture of head distal to fovea centralis, which was too small or too fragmented to be fixed with screws; II (18 cases), larger fracture of head distal to fovea centralis; III (4 cases), large fracture of head proximal to fovea centralis, and IV (3 cases), comminuted fracture of head. Excision of the head fragment was done in all 5 cases of type I and in 9 type II fractures. Fixation of the head fragment was performed in 9 type II and in all 4 type III cases. The femoral head was replaced in all 3 type IV fractures. After a mean follow-up of 3-10 years, the clinical outcome, according to Epstein et al.s critieria, were excellent in 7, good in 15, fair in 4 and poor in 1, except in type IV, and the radiographic outcome was excellent in 15, good in 7, fair in 4 and poor in 1. On the basis of our findings, we conclude that excision of the small fragment is a good choice of treatment in type 1. Early accurate reduction with stable internal fixation in type II or III permits bony union. Arthroplasty seems to be indicated in type IV.

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.

Deformity of the femoral head following vascular infarct in piglets.

Background In 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 methods In 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. Results The mean decrease in epiphyseal height was 1.5 mm, 4.1 mm, 5.0 mm, and 7.5 mm in P2, P4, P12 and P20, respectively (rs = 0.76, p = 0.002). The mean increase of diameter was 4.1 mm, 6.9 mm, and 6.8 mm 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. Interpretation The 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. ▪

The effects of subluxation of the femoral head with avascular necrosis in growing rabbits.

Abstract: To validate the adverse effects of subluxation of the femoral head in Legg-Calvé-Perthes disease, the authors made an experimental model of Perthes disease with subluxation in growing rabbits by interrupting the epiphyseal artery (devascularization) and immobilizing the knee in extension (immobilization). Seventy-two rabbits, 4 to 5 weeks old, were divided into three groups: group A with both devascularization and immobilization (25 rabbits), group B with devascularization only (25 rabbits), and group C with immobilization only (22 rabbits). In each experimental group, four to six rabbits each were killed at 1, 2, 4, 8, and 12 weeks. After reviewing the serial radiographs and gross specimens, the authors found six radiologic and six macroscopic abnormalities. The incidence and the severity of deformity in group A rabbits were higher than that of groups B or C in terms of the overall incidence of deformities (P < 0.001), head deformity scores (P < 0.001), and the incidence of a total collapse of the capital femoral epiphysis. In conclusion, subluxation of the immature femoral head with avascular necrosis in rabbits increased femoral head deformities.

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.

Toe component excision in postaxial polydactyly of the foot.

Background: Polydactyly of the fifth toe is the most common congenital malformation of the forefoot, and no consensus has been reached as to which toe component should be excised or by which surgical technique. The purpose of this study was to evaluate the results of the operative treatment of postaxial polydactyly and to offer treatment guidelines. Method: We retrospectively reviewed the details of 27 patients with postaxial polydactyly (36 feet) treated from September 2004 to March 2010. To select the dominant toe of postaxial polydactyly, we evaluated the morphological and radiological configurations. To excise the medial toe, we treated the polydactyly by dorsal rectangular flap and a full-thickness inguinal skin graft. To excise the lateral toe, we treated the polydactyly by racket-shape incision. Patient satisfaction indices were evaluated on the basis of responses to the PSQ-10 patient satisfaction questionnaire and clinical outcomes. Result: Overall surgical outcomes were satisfactory with the exception of 2 cases of skin graft problems. Eighteen of the 36 reconstructed toes were smaller than the normal toes, but valgus deformity was observed in only 3 cases. Conclusion: The described medial toe excision technique and the devised toe selection algorithm were able to satisfy functional and cosmetic requirements. Level of Evidence: Level IV, retrospective case series.

Malunion of femoral head fractures treated by partial ostectomy: three case reports.

Malunion of femoral head fractures has been rarely reported. We report on three cases of malunion of the femoral head, which were treated by partial ostectomy. All patients were involved in traffic accidents and had a posterior fracture-dislocation of the hip. The types of femoral head fractures were Pipkin type I with inferomedial fracture fragment in all cases. Initially, they were treated by closed reduction and skeletal traction for between 6 and 8 weeks. The patients were then transferred to our hospital; the chief complaint was of limited hip motion. A protruding bony mass limiting the hip motion was resected in all cases. The Smith-Petersen approach was used in all cases. The malunion sites were located distally to the original fracture site in all cases. Full weight bearing was permitted, and a range of motion exercises was started postoperatively. Excellent results were obtained with almost complete restoration of hip motion without pain. In the follow-up radiographs, there were no cases of avascular necrosis.

Computed tomographic findings of osteochondritis dissecans following Legg-Calvé-Perthes disease.

Routine radiographs in the follow-up study of Legg-Calvé-Perthes disease patient have generally been plain radiographs of the anteroposterior and frog-leg lateral view. Recently, several reports have found that osteochondritis dissecans can develop in 2% to 4% of Legg-Calvé-Perthes disease patients. Early roentgenographic recognition of this lesion is very important for its long-term prognosis. However, follow-up examination of the lesion using plain radiography is sometimes not satisfactory in terms of delineating the lesion. Accordingly, the authors performed computed tomography and three-dimensional reconstruction in 13 hips with osteochondritis dissecans following Legg-Calvé-Perthes disease and were able to obtain more precise information on the extent of the involvement, the degree of healing, the stability of the osteochondral fragment, and the location of the dislocated loose body.

Why does outer joint motion predominate in bipolar hip prosthesis

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 pre-ponderance (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.