K. M. H. Yip

Articular cartilage lesions of the knee following immobilisation or destabilisation for 6 or 12 weeks in rabbits

Eighty mature feamle New Zealand White rabbits were sacrificed 6 or 12 weeks after either section of the medial collateral and the anterior cruciate ligaments with removal of the anterior third of the medial meniscus of one knee, or immobilisation of one knee, using the contralateral non-treated knee as the control. The area of degenerated joint surface of the distal femur, and water and proteoglycan content were measured, and the articular cartilage stained using haematoxylin and eosin and safranin O. Destabilisation resulted in a significantly larger time-dependent degenerated joint surface area. Water content significantly increased after 6 weeks with no significant differences between immobilisation and destabilisation. Destabilisation resulted in a significantly greater decrease in proteoglycan content. At 12 weeks, the control knees of the animals undergoing destabilisation showed significant degenerative changes. There were more extensive lesions in destabilisation, while 6 weeks of immobilisation produced moderate degenerative joint disease.

Revascularisation of bone allografts following vascular bundle implantation : an experimental study in rats

Revascularisation and cellular repopulation of fresh and cryopreserved allografts was observed following implantation of a vascular bundle in an experimental study in rats. Fresh and cryopreserved rat allografts were harvested from Lewis rats and implanted into Spraque-Dawley rats. The femoral vascular bundle was implanted into 2-cm segments of allograft placed in the medial aspect of the thigh of the recipient rats. Non-vascularised controls were used for comparison. Histological studies indicated the revascularisation pattern. Cryopreserved allografts with vascular bundle implantation showed early neovascularisation from the endosteal surface, 20% of the necrotic lacunae was repopulated with living cells at the end of 24 weeks. Fresh allografts with vascular implantation were rejected by the host immune mechanisms and showed early breakdown and fragmentation. Cellular repopulation was not observed in the non-vascularized allografts. Secondary vascularization following a vascular bundle implantation may enhance the biological properties of an allograft and therefore has significant potential clinical applications.

Subcutaneous (inverted) verrucous carcinoma with bone invasion

Verrucous carcinoma (VC) is a low-grade cutaneous squamous carcinoma which often presents on the foot where it is known as carcinoma cuniculatum. Three cases of VC on the buttock have previously been documented. We describe a highly unusual example of VC involving the buttock with extensive iliac bone erosion, and with the apparently unique feature of being totally subcutaneous.

Cystic tuberculosis of the bone mimicking osteogenic sarcoma

Hong Kong has a relatively high incidence of tuberculosis in comparison with other developed cities, possibly due to the influx of mainland Chinese immigrants and Vietnamese boat people. However, primary, solitary cystic tuberculous infection of the bone is rare and few cases have been reported. Radiological appearances of this disease can mimic several bone conditions, including bone cyst, osteoblastoma and even osteosarcoma. We report on a case of a healthy fifteen-year-old who presented with swelling to the left elbow; biopsy confirmed this as cystic tuberculosis of the bone.

Fracture of the shaft of the humerus with a fracture-dislocation of the same shoulder

Summary.We report the case of a man aged 19 who sustained an anterior dislocation of the shoulder with a fracture of the greater tuberosity, and a fracture of the shaft of the same humerus. Open reduction and internal fixation of the shaft fracture was carried out followed by closed manipulation of the dislocation. He recovered full function of the shoulder and elbow.Résumé.Un jeune Chinois de 19 ans a été victime d’un accident de la route et a presenté une luxation de l’épaule avec fracture du trochiter et de la diaphyse humérale. Il a été traité par ostéosynthèse de la diaphyse suivie par simple réduction de la luxation d’épaule. Il n’a pas présenté de sequelle et il a récupéré une fonction normale de l’épaule et du coude. Le traitement de cette association inhabituelle de lésions est controversé mais, dans nos mains, l’ostéosynthèse de la fracture diaphysaire, suivie par la réduction de la luxation, s’est montrée efficace et sûre.

A pelvic osteosarcoma with metastasis to the donor site of the bone graft. A case report

Summary. A patient with a pelvic osteosarcoma was treated by resection and a vascularised fibular bone graft. A metastasis developed at the donor site of the graft.Résumé. Les foyers les plus communs de métastases de l’ostéosarcome sont le poumon, l’os et les parties molles. Un des modes de reconstruction après l’ablation initiale d’une tumeur primitive consiste à utiliser des greffons fibulaires vascularisés. La littérature ne fait aucune mention du développement de métastases sur le site de prélèvement de la greffe. Nous faisons le rapport d’un tel cas apparu chez un homme, jeune atteint d’ostéosarcome du pelvis, et nous essayons d’expliquer le mécanisme de propagation.

Osteosarcoma in Hong Kong.

Since 1984, the authors have treated 82 Chinese patients with sarcoma of bone. Of these patients, 58 had high grade osteosarcomas in the extremities. Of the 41 patients available for examination, the age range was 8 to 59 years, with a median of 17 years. Treatment consisted of preoperative and postoperative neoadjuvant chemotherapy, limb salvage surgery, or amputation. The overall survival rate was 62.9% at 2 years and 43% at 5 years. No significant difference was found in survival between the amputation and limb salvage groups, although local control was much better in the amputation group. There seemed to be better survival for patients who had a good response to preoperative chemotherapy, although the data did not reach statistical significance.

Ender nailing for ipsilateral femoral shaft fractures after Austin-Moore hemiarthroplasty.

BACKGROUND The management of ipsilateral femoral shaft fractures after hemiarthroplasty is controversial. METHODS Fifteen patients (average age 82.4 +/- 8 years) with ipsilateral femoral shaft fractures after uncemented hemiarthroplasty were treated by closed reduction and Ender nailing. Under radiographic control, closed reduction was attempted. If not possible, cerclage of the shaft fracture was accomplished through a limited lateral approach. Ender nails were then inserted well past the tip of the stem of the prosthesis. RESULTS There were a superficial wound infection and a deep vein thrombosis. At 6 months, five patients had died, and backing out of the nails necessitated removal in one patient. At 1 year, nine patients were still alive. Of these, seven were able to walk with aids. At 2 years, seven patients were still alive and were walking with aids. Two patients presented shortening of more than 1.5 cm of the operated femur. After an average of 5 years, 11 patients were dead, two were still walking, and two were bedridden. CONCLUSIONS The technique described is an option in the treatment of fractures of the ipsilateral femoral shaft after uncemented hemiarthroplasty.

Multiple chop wounds in Hong Kong

Knife injuries can be classified into stabbing injuries and multiple laceration or multiple chops, the latter being much more common in Chinese communities. It is the mark of criminal gang attacks with their tendency to use long knives and choppers rather than guns. The intention is often to wound rather than kill. A survey of 89 cases revealed that 90% of the victims are men, with a mean age of 27 years; 75% was admitted to the hospital at night, and in 78% of the cases the assailants were persons unknown, or so we were told by the victims. The reasons for the attacks were also not given. Most of the women victims were assaulted by their spouse. Some 74% of the patients suffered three to six lacerations; 62% of the injuries were on the extensor surfaces of the upper limbs, while the hand and the back of the trunk were also common sites. The type of management differs from that for stabbing injuries. There were no fatalities, and less than half of the patients required blood transfusion. The average hospital stay was 6.2 days. The morbidity of these injuries involves damaged tendons and nerves.

A 6-year-old girl with neck pain

A 6-year-old girl presented to the accident and emergency department after a minor twisting injury to her neck. She complained of right sided neck pain. Physical examination showed a right sided torticollis with limitation of neck motion in all directions. Marked tenderness of the upper cervical spine was present, especially on the right side. No neck mass was detected by palpation, and there was no neurologic deficit. Physical examination was otherwise unremarkable. The patient was afebrile, with a normal hemoglobin (13.4 g/L) and white cell count (8.2 x 1 03/dl). The erythrocyte sedimentation rate was 80 mm per hour. Renal and liver function tests had normal results. Radiographs of the neck were obtained (Fig l), and the neck was immobilized in a hard collar. During the week after admission, a technetium 99 isotope bone scan showed no areas of abnormal uptake, a computed tomography (CT) scan (Fig 2) and a magnetic resonance (MR) imaging scan (Fig 3) were performed. Based on the history, physical examination, laboratory, and imaging studies, what is the differential diagnosis?