Mechanical evaluation of a soft tissue interference screw in free tendon anterior cruciate ligament graft fixation.

In this study of bioabsorbable screw fixation of free tendon grafts used in anterior cruciate ligament reconstruction, we performed load-to-failure and cyclic loading of tendon fixation in porcine bone. Bone density measurements from dual photon absorptometry scans were obtained to correlate bone density with fixation failure. The average density of porcine bone (1.42 g/cm2) was similar to that of young human bone (1.30 g/cm2) and significantly higher than that of elderly human cadaveric bone specimens (0.30 g/cm2). Cyclic loading was performed on free tendon grafts fixed with a bioabsorbable screw alone and on grafts fixed with a bioabsorbable screw and an anchor (polylactic acid ball or cortical bone disk). Stiffness of fixation increased substantially with the addition of a cortical bone disk anchor or polylactic acid ball compared with the interference screw alone. Tensile fixation strength of central quadriceps free tendon and hamstring tendon grafts were significantly superior in porcine bone of density similar to young human bone than in elderly human cadaveric bone. The bioabsorbable interference screw yielded loads at failure comparable with traditional bone-tendon-bone and hamstring tendon fixation when controlled for bone density. The addition of a cortical bone disk anchor provided the most optimal fixation of free tendon with the bioabsorbable screw and reduced slippage with cyclic loading to a very low level.

Soft tissue sarcomas: ultrasonographic evaluation of local recurrences.

OBJECTIVE: The diagnosis of early local recurrence of soft tissue sarcomas, especially in those treated with surgery and radiotherapy, is a difficult clinical problem. Financial constraints led us to use ultrasonography instead of CT or MR imaging. The aim of this study was to evaluate the role of ultrasonography (US) in detecting local recurrence. METHODS AND RESULTS: Fifty patients with previous treatment for soft tissue sarcomas were evaluated prospectively for recurrence by US and histopathology. Seven of the 50 patients were clinically suspected to have recurrent tumour. Ultrasonography showed recurrence in 26, no recurrence in 18, benign disease in four and was indeterminate in two cases. Ultrasonography was instrumental in guiding fine needle aspiration biopsies of small local recurrences and indeterminate lesions in 17 patients. In the sonographically tumour positive patients, histopathology confirmed recurrence in 24; one case had benign disease and one patient refused surgery. Thirteen of the 18 sonographically tumour negative patients were operated upon; all were negative for tumour on histopathology. Both the indeterminate cases showed recurrence on histopathology. The benign cases were confirmed by histopathology correlation. Ultrasound guided fine needle aspiration cytology (FNAC) was positive in 14 out of 17 patients (88%). The sensitivity and specificity of US was 92.30% and 94.4% respectively. CONCLUSION: Our study concludes that US is an extremely useful and cost effective method in the detection of early local recurrences of soft tissue sarcomas and should therefore be used for initial routine follow-up and guided biopsies.

Not all rods are Harrington - an overview of spinal instrumentation in scoliosis treatment.

BACKGROUND: Scoliosis is a multiplanar spinal deformity, which has been treated in the past with spinal fusion and cast application, starting in the early part of this century. In the last 30 years, Paul Harrington successfully introduced spinal instrumentation for scoliosis. Harrington instrumentation has had a large impact on the treatment of scoliosis. Currently, there are many different instrumentations available for the treatment of scoliosis. Indications differ for the use of these systems. Appreciation of spinal instrumentation is essential to treatment of the patient with scoliosis. Post-operative roentgenographic studies are better understood when the interface between instrumentation and the spine is understood. MATERIALS AND METHODS: Distinguishing characteristics between some of the more common instrumentations are noted. There continues to be a proliferation of spinal instrumentation systems. Roentgenograms and spinal models are used to explain how some of the instrumentation systems differ and how they interface with the spine. CONCLUSION: An overview of spinal instrumentation in scoliosis treatment will allow better understanding of the purposes of the hardware and how it relates to the spine.

Charcot arthropathy in spina bifida.

This multicenter study was undertaken to identify the prevalence of Charcot arthropathy in the spina bifida population; to evaluate the relationship of neurosegmental level, ambulatory level, and distribution of joint involvement; and to assess treatment results and make treatment recommendations. Sixteen patients were identified with Charcot arthropathy based on clinical and radiographic criteria ranging in age from 9 to 42 years. There were 15 ankles, seven knees, and four hips identified with Charcot arthropathy. Six patients underwent surgery and modification of orthoses, eight had a modification of orthoses only, one had no modification, and one was lost to follow-up. Mean follow-up was 4 years and 9 months (with four good, 17 fair, and five poor results). The best results were seen in 13 compliant patients with a brace modification, whereas poor results were seen in three patients with poor brace compliance. Based on our study, we have noted the prevalence of Charcot arthropathy in spina bifida to be one in 100 cases.

Phosphorylation of cytosolic phospholipase A2 and the release of arachidonic acid in human neutrophils.

Kinases mediating phosphorylation and activation of cytosolic phospholipase A2 (cPLA2) in intact cells remain to be fully characterized. Platelet-activating factor stimulation of human neutrophils increases cPLA2 phosphorylation. This increase is inhibited by PD 98059, a mitogen-activated protein (MAP)/extracellular signal-regulating kinase (erk) 1 inhibitor, but not by SB 203580, a p38 MAP kinase inhibitor, indicating that this action is mediated through activation of the p42 MAP kinase (erk2). However, platelet-activating factor-induced arachidonic acid release is inhibited by both PD 98059 and SB 203580. Stimulation by TNF-alpha increases cPLA2 phosphorylation, which is inhibited by SB 203580, but not PD 98059, suggesting a role for p38 MAP kinase. LPS increases cPLA2 phosphorylation and arachidonic acid release. However, neither of these actions is inhibited by either PD 98059 or SB 203580. PMA increases cPLA2 phosphorylation. This action is inhibited by PD 98059 but not SB 203580. Finally, FMLP increases cPLA2 phosphorylation and arachidonic acid release. Interestingly, while the FMLP-induced phosphorylation of cPLA2 is not affected by the inhibitors of the p38 MAP kinase or erk cascades, both inhibitors significantly decrease arachidonic acid release stimulated by FMLP. SB 203580 or PD 98059 has no inhibitory effects on the activity of coenzyme A-independent transacylase.

Role of p38 MAP kinase in myocardial stress.

The current study focuses on the role of p38 MAP kinase in response to acute preconditioning stimuli and ischemia. Exposure of the rat myoblast cell line H9C2 to preconditioning stimuli, viz. brief duration of ischemia (metabolic inhibition) and adenosine, led to activation of p38 MAP kinase. The protective preconditioning effect of these stimuli against lethal ischemic insult was abolished in the presence or p38 MAP kinase inhibitor SB 203580 but not in the presence of MEK inhibitor PD 98509. Phorbol myristate acetate, PMA, which activates protein kinase C, PKC, activates p38 MAP kinase. and this activation is inhibited by PKC inhibitor G. 6850. The preconditioning effect of PMA was abolished by SB 203580 and also by protein kinase C inhibitor Go 6850. This indicates that the protective action of preconditioning by PKC is mediated via activation of p38 MAP kinase. Paradoxically, the presence of SB 203580 and Go 6850 during the lethal stress protected the cells against cell death. The mode of cell death in this study whether necrotic or apoptotic has not been established. Lethal ischemic stress activates p38 MAP kinase. Preconditioning the cells decreases the activation of p38 MAP kinase in response to the second lethal stress. These findings highlight the role of p38 MAP kinase in ischemic preconditioning v ischemia. Furthermore, our findings in an in vitro model using a proliferating cell line indicate that the duration and/or intensity of stimuli activating p38 kinase probably determines whether it would play a beneficial v deleterious role in cell survival in response to stress.

Cost effective treatment of osteogenic sarcoma of the extremities.

In an ongoing trial at our institute 10 patients of high grade osteogenic sarcoma of the extremities have been treated with preoperative chemotherapy including ifosfamide 2 mg/M2/day i.v. for 5 days, doxorubicin 20 mg/M2/day i.v. for 3 days and cisplatinum 120 mg/M2 i.v. on day 1 at 3-4 weeks interval for 2 courses followed by surgery. One patient refused surgery and further treatment. Pathological study of the 9 surgical specimens showed grade IV necrosis in 5, grade III necrosis in 2 and grade I & II necrosis in 2. Overall response rate (Grade III & IV) was 87.5%. The patients showing Grade III/IV response received a further 3 cycles of the same chemotherapy postoperatively. The patient who refused surgery is still alive at 30 months. Our followup ranges from 4-34 months. All patients developed myelosuppression and one patient died after 4th course of chemotherapy due to septicemia. We expect grade IV response to preoperative chemotherapy will be translated into longer disease free survival. Protocols followed in western countries are not practicable in Asian countries. Hence this new combination has been developed without compromising response rate.

Modulation of Kupffer cell activity by Tinospora cordifolia in liver damage.

Kupffer cells are major determinants of outcome of liver injury. Their activity was therefore studied in a model of chronic liver disease. The effect of Tinospora cordifolia, an indigenous agent with proven hepatoprotective activity, was evaluated on Kupffer cell function, using carbon clearance test as a parameter. Rats were divided into two major groups. In Gp I which served as normal control t1/2 of carbon was 9.48 +/- 4.14 min. GpII received horse-serum in a dose of 0.5 ml/100 gm b.w. i.p. for a period of 12 weeks and was divided into three sub-groups. In Gp IIA at the end of 12 weeks half-life of carbon was found to be significantly increased to 19.86 +/- 7.95 min (p < 0.01). Indicating suppressed Kupffer cell function in chronic liver damage. In Gp IIB treated with vehicle for 4 more weeks there was significant prolongation of half-life to 38.32 +/- 10.61 min (p < 0.01), indicating perpetuation of damage in absence of damaging agent. Whereas in Gp IIc, treated with Tinospora cordifolia t 1/2 was decreased to 14.24 7.74 min (p < .01), as compared to vehicle control indicating a significant improvement in Kupffer cell function and a trend towards normalization.