The Oxford unicompartmental knee prosthesis for the treatment of medial compartment knee disease: 2 to 5 year follow-up.

BACKGROUND: Unicompartmental knee replacement has become a surgical alternative for treating isolated medial or lateral osteoarthritis of the knee or avascular necrosis of the femoral condyls. OBJECTIVES: To evaluate the short-term results of the Oxford Phase 3 unicompartmental knee replacement for unicompartmental knee arthrosis or avascular necrosis of the medial femoral condyle. METHODS: During the period 2003-2005 a total of 59 patients (59 knees) underwent medial Oxford Phase 3 unicompartmental knee replacement in our unit. The patients were interviewed and examined, and standing anteroposterior and lateral X-rays were taken. All patients completed the Western Ontario and McMaster Universities Index of Osteoarthritis and the Short Form 12 questionnaire, and the International Knee Society score was evaluated. The data were collected and statistical analysis was performed. RESULTS: X-rays were performed and scores for the WOMAC and IKS were assessed for 42 patients (31 females, 11 males). At an average of 32 months after surgery the total WOMAC score was 30. The mean SF-12 physical score was 38 and the mean SF-12 mental score was 51. The mean IKS score was 166. Ninety-one percent of the patients had active flexion of 120 degrees or more. Of 59 knees 7 were converted to total knee arthroplasty--all of them within the first 2 years of starting the procedure and all of them in relatively young patients. CONCLUSIONS: Despite the higher revision rate to TKR in this study, our findings confirm the short-term results reported in other studies of the Oxford medial unicompartmental knee and our early failure rate could be explained by a performance learning curve. This study confirms that this bone-preserving procedure should be considered in end-stage isolated unicompartmental osteoarthritis or avascular necrosis by surgeons who have the adequate training and experience.

The perichondrial ring as a reservoir for precartilaginous cells. In vivo model in young chicks' epiphysis.

BACKGROUND: The purpose of this study is to illustrate the routes of migration of precartilaginous cells from the perichondrial ring of LaCroix, as a potential reservoir for growth-plate germ cells. METHODS: Chondrocytes derived from the ring of LaCroix of young chicks' proximal tibia were cultured in vitro and transfected with adenovirus vector containing the gene encoding for Escherichia coli (beta)-galactosidase (lacZ) gene, which allows assessment of the migratory routes of these cells. The lacZ- transfected cells were injected back into the perichondrial ring of LaCroix of young chicks' proximal tibias. Four weeks later the migration root was assessed microscopically. RESULTS: Injection of cells derived from the ring of LaCroix of neonate chicks, transfected in culture with adenoviruses containing LacZ reporter gene, allows the assessment of migratory potential of these cells. Stained cells were found at the outer layer of the epiphysis, particularly in areas adjacent to the perichondrial ring. Further longitudinal histopathological studies along the bone axis demonstrated a condensed layer of the stained cells arranged horizontally along parts of the physis. CONCLUSION: The perichondrial ring of LaCroix represents a potential reservoir of growth-plate germ cells in young chicks.

Percutaneous pinning using threaded pins as a treatment option for unstable two- and three-part fractures of the proximal humerus: a retrospective study.

A retrospective study was designed to evaluate the results of closed reduction and percutaneous pinning using threaded pins as a treatment option for fractures of the humeral head. Patients who suffered two- and three-part fractures of the proximal humerus treated by this method of fixation were included. Fifty patients (32 females and 18 males) with an average age of 50 years were clinically evaluated at an average of 2.5 years after this procedure (range 1-4 years). The Constant score was used to evaluate the clinical outcome. Preoperative and postoperative X-rays were also assessed. Out of 50 patients, 18 (36%) obtained excellent results, 17 (34%) good results, eight (16%) fair results and seven (14%) achieved only poor results. The average Constant score was 81 (range 60-100). Fractures confined to the surgical or anatomical neck generally did better than those associated with a greater tuberosity fragment (average score 86 versus 78). Patients who required shaft stabilisation and in addition to reduction and fixation of the greater tuberosity showed a lower average score (68). There were no cases of avascular necrosis, neurovascular complications or deep infections. A significant loss of fracture position due to failure of internal fixation occurred in seven cases, three of these patients underwent revision surgery. Closed reduction and percutaneous pinning offers a good fracture position and stability with minimal soft tissue damage. We recommend that displaced two- and three- part fractures of the humeral head should be treated in this manner. However these patients should be monitored closely for a period of four weeks, since secondary displacement and failure of fixation can occur in this period. Careful patient selection may minimise these complications.

Percutaneous CT-guided curettage of osteoid osteoma with histological confirmation: a retrospective study and review of the literature.

Osteoid osteoma is a benign bone tumour usually occurring in young individuals (10-30 years). It presents with intense pain (typically nocturnal), which can be alleviated by salicylates. Treatment consists of surgical excision or destroying the nidus and it is curative. In the past, surgery was performed in an "open" fashion and the nidus had to be removed with a bone block. This extensive type of surgery could be associated with some rates of both failure and complication. There is growing evidence to suggest that percutaneous CT-guided removal or destruction of the nidus is a good alternative and it is indeed gaining worldwide popularity. We present a series of 18 consecutive patients with osteoid osteoma of the pelvis, femur, and tibia, treated percutaneously under CT guidance. Removal of the nidus was performed using a 4.5-mm cannulated drill and a cannulated curette of our own design. Tissue samples for histological evaluation were obtained in the same way. The mean follow-up time was 29 months. Sixteen patients were initially cured. The procedure had to be repeated in two patients and was eventually successful (primary and secondary success rates 88 and 100% respectively). The diagnosis was histologically confirmed in 14 cases out of 18 (77%). In four cases no histological confirmation of osteoid osteoma could be achieved. There were only two minor complications, one case of femoral neuropraxia and one case of skin abrasion. Percutaneous CT-guided removal seems to be efficient and safe for the treatment of osteoid osteoma. The use of a cannulated drill and a cannulated curette facilitates efficient removal of the tumour and procurement of tissue for diagnosis.

The use of external fixation for the treatment of spine infection with Actinomyces bacillus.

OBJECTIVE: External fixation can be used for stabilization of the spine in salvage cases, especially in cases of infection of the spine. The advantages of this method are avoiding the needs for internal fixation devices and for postoperative bracing. The literature on this is scant. Reported is a rare case of osteomyelitis of the D2 vertebra with an epidural abscess caused by Actinomyces israelii that spread from the lung and was treated by decompression and external fixation. METHODS: A 51-year-old man with right upper lobe pneumonia due to A. israelii coccobacillus developed osteomyelitis of the D2 vertebra and an epidural abscess with a gradual paraparesis. He underwent a laminectomy of D1-D3 and 3 weeks later stabilization of the upper thoracic spine using a tubular external fixator that was inserted from C7-D1 to D3-D4. The patient was treated with antibiotic intravenously and later orally. After 2 months, the external fixator was removed. RESULTS: At the last follow-up, the patient had no fever, the erythrocyte sedimentation rate and C-reactive protein level had normal values, and there was only a slight limitation in the range of motion of the cervical paraparesis. Radiography and magnetic resonance imaging demonstrated stabilization of the affected segment without any sign of active osteomyelitis. There were no complications associated with the use of the external fixator. CONCLUSIONS: The use of external fixation offers an appropriate alternative for stabilization of the spine as a salvage procedure. The procedure could be performed easily and without any major complications. Especially for the treatment of complicated cases of spinal infection, the use of an external fixator can be of great benefit.