Bilateral knee lipoma arborescens: a case report.

A 45-year-old Chinese man presented with recurrent bilateral knee swelling and pain. He was initially diagnosed with gouty arthritis, but later found to have lipoma arborescens. Magnetic resonance imaging demonstrated frond-like proliferations of fatty synovium. Arthroscopic synovectomy was performed. Histological examination of the specimen revealed villiform fatty tissue covered by slightly thickened synovium characteristic of lipoma arborescens. Magnetic resonance imaging is useful in differentiating lipoma arborescens from other intra-articular lesions in patients with recurrent knee pain and swelling.

The management of superior dislocation of the patella with interlocking osteophytes--an update on a rare problem.

The superior dislocation of the patella with interlocking osteophytes is a rare condition. A review of the English literature revealed only 12 reported cases. The purpose of reviewing these case reports is to highlight the unusual presentation and the injury mechanism in 2 of our patients, and to present our treatment algorithm. Closed reduction with manipulation of the patella, with or without anaesthesia, was performed without difficulty. We recommend an intermediate step of trying a regional nerve block before proceeding to general anaesthesia. Our patients had full range-of-motion after reduction and they were symptom-free after 3 years of follow-up. There were no recurrent dislocations in our patients.

Local recurrence of parosteal osteosarcoma adjacent to a prosthesis after 20 years: a case report.

We describe the treatment of an uncommonly late presentation of a recurrent parosteal osteosarcoma of the distal femur. The osteosarcoma had originally been detected 20 years earlier, and had been treated with wide excision and mega-prosthesis to reconstruct the femur. The tumour recurred in close proximity to the femur prosthesis and encased half the femoral stem. Because there was a large piece of metal at the site of recurrence, which might have interfered with computed tomography and magnetic resonance imaging, ultrasonography was used to locate the lesion. The tumour was successfully treated with wide local re-excision. This case emphasises the importance of the long-term follow-up of patients with parosteal osteosarcoma.

Use of bisphosphonate to manage avulsion fracture of tibial tuberosity with underlying angiomatosis: a case report.

An unusual case of avulsion fracture of the tibial tuberosity with underlying angiomatosis in a middle-aged man is described, with particular emphasis on the successful use of bisphosphonate in its treatment and the value of serial dual energy X-ray absorptiometry in its subsequent disease monitoring. This case illustrates the importance of careful correlation of the clinical, radiological, and histological findings in the management of skeletal tumour and tumour-like lesions. The differential diagnosis of osteolysis with vascular ectasia is discussed.

Full weight bearing after non-cemented total hip replacement is compatible with satisfactory results.

Two matched groups of 29 patients underwent hydroxyapatite-coated non-cemented total hip replacement. One group was started on immediate protected-weight-bearing walking and the other group was started on immediate full-weight-bearing walking. They were followed up regularly for 2 years. They were assessed with Harris hip score clinically and Engh's criteria of osteo-integration radiographically. No difference was found between the two groups. All patients had excellent clinical outcome after hip replacement, and all femoral stems were stable radiographically. Patients can walk with full weight bearing safely immediate after hydroxyapatite-coated non-cemented total hip replacement.

Modified arthroscopic suture fixation of displaced tibial eminence fractures using a suture loop transporter.

Current arthroscopic suture fixation techniques of tibial eminence fractures are time consuming and the number of anchor sutures that can be placed is limited by the cumbersome and repetitive numerous needle threading steps. This occurs at 2 stages: first, when placing anchoring sutures through the avulsed anterior cruciate ligament stump with a suture punch, and second, when there is a need to traverse the tibial bone canal with the suture ends. We describe a modification that reduces the reliance on conventional rigid instruments and instead uses a loop transporter made from readily available suture material. The suture loop transporter being malleable reduces the necessary width of the tibial bone canal to be made and has a further advantage of minimizing the bone loss during the reaming of the bone tunnel. The subsequent potential for a stress fracture at these tunnel sites is also substantially reduced. Our technique is more user friendly, more accurate, and quicker to perform.

Report of 2 fatal cases of adult necrotizing fasciitis and toxic shock syndrome caused by Streptococcus agalactiae.

We describe 2 cases of fatal necrotizing fasciitis and toxic shock syndrome caused by Streptococcus agalactiae-a rare entity that has been reported in only 9 patients-in 2 nonpregnant adults.

Magnetic resonance imaging of lumbar vertebral apophyseal ring fractures.

Posterior lumbar vertebral apophyseal ring fractures are described in three adolescents presenting with severe low back pain, spinal tenderness and lower limb neurological deficit. Magnetic resonance imaging showed severe L4/5 posterior disc protrusion in all three patients. The actual fracture fragment was visualized with difficulty on MRI alone. The diagnosis of apophyseal ring fracture was made by either radiography or CT. Computed tomography delineated the size, shape and site of the fracture fragment. Surgical confirmation was obtained in all cases. Posterior lumbar vertebral apophyseal ring fractures may be difficult to visualize on MR imaging. Careful review of radiographs, supplemented by targeted CT, is necessary for the correct diagnosis and management of this entity.

Magnetic resonance imaging of subcutaneous diffuse neurofibroma.

A 31-year-old woman presented with increasing pain and tenderness of a long-standing soft tissue mass on her back. MRI showed a network of interconnecting tubular areas, which were T1 isointense and T2 hyperintense relative to skeletal muscle, and displayed marked Gd-DTPA enhancement. The lesion was situated within the subcutaneous fat. Clinically and radiologically, this mass was considered to be a subcutaneous venous haemangioma. Histological examination of the excised mass showed a diffuse neurofibroma with ectatic vessels and entrapped adipose tissue. Similar MRI appearances of subcutaneous haemangioma and diffuse neurofibroma may result in failure to make the correct diagnosis and in inappropriate management.

Purification of a pituitary polypeptide that stimulates the replication of adipocyte precursors in culture.

A bovine anterior pituitary polypeptide that stimulates the replication of rat and human adipocyte precursors has been purified. Its Mr is 44 000-53 000 and its isoelectric point is 9.8-10.3. While pituitary basic fibroblast growth factor is equally mitogenic on adipocyte precursors and skin fibroblasts, the polypeptide described here is selectively more active on the precursors. We postulate that this adipocyte growth factor plays a physiological role by modulating the number of adipocyte precursors.

Structural and functional heterogeneity of the surface of rat leukemia cells.

Rat leukemia cells IRC 741 in suspension culture form single cytoplasmic protrusions by which the cells preferentially adhere to one another. The induction and/or maintenance of these protrusions is sensitive to changes in intercellular contact, pH, temperature, and nutritional conditions. The protrusions are stable, rigid structures which take part in intercellular adhesion but not in adhesion to substrata. Movement on substrata occurs by means of ruffling membranes formed on the main cell body. This asymmetry in cellular form and function is associated with specialized cell surface regions. Ultrastructurally, the cell surface over the protrusions lacks microvilli, and is covered with a 3,000-4,000-A thick cell coat consisting of 200-500-A electron-dense particles in an amorphous matrix. In contrast, the surface over the main cell body has microvilli and a 200-A wide cell coat which lacks particles. The extracellular particles overlying the protrusions have electron-lucent cores, are protease- and pepsin-resistant, and do not stain with colloidal iron, while the matrix in which they are embedded is sensitive to proteolytic enzymes and contains acidic moieties. The negative surface charge density over the protrusions is higher than that over the main cell body, as shown by the orientation of the cells in an electric field. The unexpected observation that a region of higher charge density is one of increased intercellular adhesiveness might be explained, in part, by the rigidity of the protrusions and by the very small radius of curvature of the overlying extracellular particles. The protrusions permit the observation of discrete regions, differing in charge density, on the surface of living leukemia cells.