Histone deacetylases and cancer: causes and therapies

Together, histone acetyltransferases and histone deacetylases (HDACs) determine the acetylation status of histones. This acetylation affects the regulation of gene expression, and inhibitors of HDACs have been found to cause growth arrest, differentiation and/or apoptosis of many tumours cells by altering the transcription of a small number of genes. HDAC inhibitors are proving to be an exciting therapeutic approach to cancer, but how do they exert this effect?

Clinical Experience With Intravenous and Oral Formulations of the Novel Histone Deacetylase Inhibitor Suberoylanilide Hydroxamic Acid in Patients With Advanced Hematologic Malignancies

Purpose

To document the toxicity and activity of the histone deacetylase inhibitor suberoylanilide hydroxamic acid (SAHA) in patients with pretreated hematologic malignancies.

Patients and Methods

Two formulations of SAHA (intravenous [IV] and oral) have been assessed in two consecutive phase I trials. In both trials, dose escalation was performed in parallel and independently in patients with solid tumors and hematologic malignancies. Eligible patients were required to have adequate hepatic and renal function, an absolute neutrophil count ≥ 500/μL and a platelet count more than 25,000/mL. All patients provided informed consent for study inclusion.

Results

A total of 39 patients with hematologic malignancy were enrolled (14 on IV SAHA and 25 on oral SAHA), of whom 35 were treated. The spectrum of diseases included patients with diffuse large B-cell lymphoma (n = 12), Hodgkin's disease (HD; n = 12), multiple myeloma (n = 2), T-cell lymphoma (n = 3), mantle cell lymphoma (n = 2), small lymphocytic lymphoma (n = 2), and myeloid leukemia (n = 2). Major adverse events with the oral formulation included fatigue, diarrhea, anorexia, and dehydration, whereas myelosuppression and thrombocytopenia were more prominent with the IV formulation. Typically, the hematologic toxicities resolved shortly after SAHA was stopped. There was no neutropenic fever or neutropenic sepsis. Reduction in measurable tumor was observed in five patients. One patient with transformed small lymphocytic lymphoma met criteria for complete response, whereas another met the criteria for partial response (PR). One patient with refractory HD had a PR, whereas three patients had stable disease for up to 9 months.

Conclusion

These results suggest that SAHA has activity in hematologic malignancies including HD and select subtypes of non-Hodgkin's lymphoma.

The efficacy of platelet-rich plasma in the treatment of symptomatic knee osteoarthritis: a systematic review with quantitative synthesis

PURPOSE

The purpose of this systematic review was to synthesize the available Level I and Level II literature on platelet-rich plasma (PRP) as a therapeutic intervention in the management of symptomatic knee osteoarthritis (OA).

METHODS

A systematic review of Medline, Embase, Cochrane Central Register of Controlled Trials, PubMed, and www.clinicaltrials.gov was performed to identify all randomized controlled trials and prospective cohort studies that evaluated the clinical efficacy of PRP versus a control injection for knee OA. A random-effects model was used to evaluate the therapeutic effect of PRP at 24 weeks by use of validated outcome measures (Western Ontario and McMaster Universities Arthritis Index, visual analog scale for pain, International Knee Documentation Committee Subjective Knee Evaluation Form, and overall patient satisfaction).

RESULTS

Six Level I and II studies satisfied our inclusion criteria (4 randomized controlled trials and 2 prospective nonrandomized studies). A total of 577 patients were included, with 264 patients (45.8%) in the treatment group (PRP) and 313 patients (54.2%) in the control group (hyaluronic acid [HA] or normal saline solution [NS]). The mean age of patients receiving PRP was 56.1 years (51.5% male patients) compared with 57.1 years (49.5% male patients) for the group receiving HA or NS. Pooled results using the Western Ontario and McMaster Universities Arthritis Index scale (4 studies) showed that PRP was significantly better than HA or NS injections (mean difference, -18.0 [95% confidence interval, -28.8 to -8.3]; P < .001). Similarly, the International Knee Documentation Committee scores (3 studies) favored PRP as a treatment modality (mean difference, 7.9 [95% confidence interval, 3.7 to 12.1]; P < .001). There was no difference in the pooled results for visual analog scale score or overall patient satisfaction. Adverse events occurred more frequently in patients treated with PRP than in those treated with HA/placebo (8.4% v 3.8%, P = .002).

CONCLUSIONS

As compared with HA or NS injection, multiple sequential intra-articular PRP injections may have beneficial effects in the treatment of adult patients with mild to moderate knee OA at approximately 6 months. There appears to be an increased incidence of nonspecific adverse events among patients treated with PRP.

LEVEL OF EVIDENCE

Level II, systematic review of Level I and II studies.

The electromechanics of DNA in a synthetic nanopore

We have explored the electromechanical properties of DNA on a nanometer-length scale using an electric field to force single molecules through synthetic nanopores in ultrathin silicon nitride membranes. At low electric fields, E < 200 mV/10 nm, we observed that single-stranded DNA can permeate pores with a diameter >/=1.0 nm, whereas double-stranded DNA only permeates pores with a diameter >/=3 nm. For pores <3.0 nm diameter, we find a threshold for permeation of double-stranded DNA that depends on the electric field and pH. For a 2 nm diameter pore, the electric field threshold is approximately 3.1 V/10 nm at pH = 8.5; the threshold decreases as pH becomes more acidic or the diameter increases. Molecular dynamics indicates that the field threshold originates from a stretching transition in DNA that occurs under the force gradient in a nanopore. Lowering pH destabilizes the double helix, facilitating DNA translocation at lower fields.

A Prospective Randomized Clinical Trial in Total Hip Arthroplasty-Comparing Early Results Between the Direct Anterior Approach and the Posterior Approach

BACKGROUND

We report a prospective randomized study comparing early clinical results between the direct anterior approach (DAA) and posterior approach (PA) in primary hip arthroplasty.

METHODS

Surgeries were performed by 2 senior hip arthroplasty surgeons. Seventy-two patients with complete data were assessed preoperatively 2, 6, and 12 weeks postoperatively. The primary outcomes were the Western Ontario McMasters Arthritis Index and Oxford Hip Scores. Secondary outcome measures included the EuroQoL, 10-meter walk test, and clinical and radiographic parameters.

RESULTS

Data analyses showed no difference between DAA (n = 35) and PA (n = 37) groups when comparing total scores for primary outcomes. No significant differences were observed for 10-meter walk test, EuroQoL, and radiographic analyses. Subgroup analysis for surgeon 1 identified that the DAA group had shorter acute hospital stay, less postoperative opiate requirements, and smaller wounds. However, this was offset by increased operative time, higher intraoperative blood loss, and weaker hip flexion at 2 and 6 weeks. Subgroup analysis of items on the Western Ontario McMasters Arthritis Index and Oxford Hip Score identified that hip flexion activity favored the DAA group up to 6 weeks postoperatively. There was an 83% incidence of lateral cutaneous nerve of thigh neuropraxia at the 12-week mark in the DAA group. No neuropraxias occurred in the PA group. One dislocation occurred in each group. A single patient from the DAA group required reoperation for leg-length discrepancy.

CONCLUSION

DAA total hip arthroplasty (THA) has comparable results with PA THA. Choice of surgical approach for THA should be based on patient factors, surgeon preference, and experience.

Effective treatment of injecting drug users with recently acquired hepatitis C virus infection

BACKGROUND & AIMS

Patients with acute hepatitis C virus (HCV) infection who receive treatment achieve high rates of sustained virologic response (SVR), but few studies have examined outcomes among injecting drug users (IDUs). We evaluated the efficacy of treatment of recent HCV infection in IDUs with acute and early chronic HCV.

METHODS

We analyzed data from the Australian Trial in Acute Hepatitis C-a prospective study of the natural history and treatment outcomes of patients with recent HCV infection. Participants eligible for the study had their first anti-HCV antibody-positive test result within the past 6 months and either acute clinical HCV within the past 12 months or documented anti-HCV seroconversion within 24 months. Participants with HCV received pegylated interferon-alfa-2a (180 microg/wk, n = 74); those with HCV/human immunodeficiency virus (HIV) co-infection received pegylated interferon-alfa-2a (180 microg/wk) with ribavirin (n = 35) for 24 weeks.

RESULTS

From June 2004 to February 2008, 167 participants were enrolled in the Australian Trial in Acute Hepatitis C; 79% had injected drugs in the previous 6 months. Among 74 with only HCV, the SVRs were 55% and 72% by intention-to-treat and per-protocol analysis, respectively. In multivariate analyses, baseline factors independently associated with lower SVR included decreased social functioning and current opiate pharmacotherapy. Adherent participants had higher SVR rates (63% vs 29%; P = .025). Of the 35 participants with HCV/HIV co-infection, the SVRs were 74% and 75% by intention-to-treat and per-protocol analysis, respectively.

CONCLUSIONS

Treatment of recent HCV infection among IDUs, including those with HIV co-infection, is effective. Strategies to engage socially marginalized individuals and increase adherence should improve treatment outcomes in this population.

Adhesion of Staphylococcus to orthopaedic metals, an in vivo study

This study describes a new model of biofilm study in rabbits. The primary focus of this study was to assess biofilm adhesion to orthopaedic metals in their first 48 h in a femoral intramedullary implantation model. Two previous inoculation methods i.e. that of pre- and direct inoculation were studied with two bacterial isolates namely Staphylococcus aureus and epidermidis, on titanium and stainless steel metallic implants. A method of sonication and log dilution/plating was used to assess biofilm bacteria adhering to implants. Silver coated metals were then compared with their respective control metals in the new model. The direct inoculation model gave larger and more reproducible biofilm adhesion to implanted metals. Staphylococcus epidermidis shows lower adhesion ability to metals, and biofilms adhere in greater numbers to stainless steel over titanium. Silver coated metals show no statistical difference over control metals when exposed to orthopaedic biofilms.

Arthroscopic repair of combined Bankart and superior labral detachment anterior and posterior lesions: technique and preliminary results

Over a 3-year period nine of 585 patients undergoing shoulder surgery were found to have a superior labral detachment anterior and posterior (SLAP) lesion. Seven patients also had an associated Bankart lesion and underwent arthroscopic repair of the entire anterior-inferior-superior-posterior labral detachment using the Suretac (Acufex Microsurgical Inc., Mansfield, MA) fixation device. The technique used requires an accessory anterior-lateral portal to access the superior-posterior labral detachment and an accessory anterior-inferior portal to access the Bankart lesion. Three to four Suretacs were required for repair in these cases. At an average follow-up of 19 months (range 15-22), five of seven patients had no pain, full range of motion, and a full premorbid activity level. One patient redislocated at 4 months postoperatively and was successfully managed with an open repair, and one patient developed a stiff shoulder that was successfully managed with arthroscopic release and manipulation. We conclude that this arthroscopic technique is a useful method to manage extensive labral detachment in selected patients.

Characteristics and treatment outcomes among HIV-infected individuals in the Australian Trial in Acute Hepatitis C

BACKGROUND

The Australian Trial in Acute Hepatitis C (ATAHC) is a National Institutes of Health-funded prospective cohort study of the natural history and efficacy of treatment in individuals with recently acquired hepatitis C. Enrollment is open to both human immunodeficiency virus (HIV)-infected and -uninfected individuals. The aim of this article was to evaluate characteristics and virological outcomes among HIV-infected individuals enrolled in ATAHC.

METHODS

Eligibility criteria included the first positive result of testing for anti-hepatitis C virus (HCV) antibody within 6 months and either clinical hepatitis diagnosed within the past 12 months or documented anti-HCV seroconversion within the past 24 months.

RESULTS

Of the initial 103 patients enrolled, 27 (26%) were HIV infected. HIV-infected patients were more likely to be older, to have HCV genotype 1 infection and high levels of HCV RNA at baseline than were HCV-monoinfected patients. Sexual acquisition accounted for the majority (56%) of HCV infections among HIV-infected patients, compared with only 8% of HCV-monoinfected patients. The median duration from estimated HCV infection to treatment was 30 weeks. Treatment with 24 weeks of pegylated interferon and ribavirin resulted in rates of undetectability of HCV RNA of 95%, 90%, and 80% at weeks 12, 24, and 48, respectively. Undetectability at week 4 was achieved in 44% of patients and yielded positive and negative predictive values for sustained virological response of 100% and 33%, respectively.

CONCLUSIONS

Significant differences were demonstrated between HIV-infected and HIV-uninfected individuals enrolled in ATAHC. Treatment responses among HIV-infected individuals with both acute and early chronic infection are encouraging and support regular HCV screening of high-risk individuals and early treatment for recently acquired HCV infection.

A Randomized Trial of Ultrasound-guided Brachial Plexus Anaesthesia in Upper Limb Surgery

Ultrasound guidance allows real-time identification of relevant anatomy and needle position when performing brachial plexus regional anaesthesia. The aim of this investigation was to determine whether the use of surface ultrasound could improve the quality of brachial plexus anaesthesia for upper limb surgery. Forty patients were randomized to either conventional “landmark-based” plexus anaesthesia, or to an ultrasound-guided approach using a 13 mHz linear array transducer. Both interscalene and axillary techniques were used. The use of ultrasound significantly improved the onset and completeness of sensory (P=0.011) and motor (P=0.002) block. Ultrasound guidance also significantly reduced (P=0.012) the incidence of paraesthesia during the performance of the blocks. Ultrasound guidance increases the quality of sensory and motor blockade in brachial plexus regional anaesthesia, and by reducing the incidence of paraesthesia during performance of the blocks, may confer greater safety.

Anterior cruciate ligament reconstruction grafts: MR imaging features at long-term follow-up--correlation with functional and clinical evaluation

PURPOSE

To assess the presence of increased intrasubstance signal intensity within anterior cruciate ligament (ACL) grafts and to assess whether such signal intensity changes are correlated to clinical assessments of graft instability and patient function 4-12 years after ACL reconstruction.

MATERIALS AND METHODS

Ethical permission and written informed patient consent were obtained. The study was HIPAA compliant. Forty-seven patients were included and underwent 1.5-T magnetic resonance (MR) imaging of the knee that was treated surgically. Signal intensity characteristics of the ACL graft were evaluated on sagittal intermediate-weighted and sagittal and axial T2-weighted fast spin-echo MR images. The amount of signal intensity change, femoral and tibial graft tunnel position, and orientation of ACL graft in the coronal plane were assessed. Objective index of graft stability or laxity was performed with arthrometric testing, and subjective function was assessed by using International Knee Documentation Committee (IKDC) scoring.

RESULTS

Increased intrasubstance graft signal intensity was found in 70 % (33 of 47) and in 64% (30 of 47) of patients on intermediate-weighted MR images and T2-weighted MR images, respectively. When present, intrasubstance graft signal intensity changes involved less than 25% of the maximal cross-sectional area of the graft in 70% (23 of 33) of cases on intermediate-weighted acquisitions and in 70% (21 of 30) of cases on T2-weighted acquisitions. No significant association was seen between graft signal intensity changes on intermediate-weighted and T2-weighted images and IKDC score (P = .667 and .698, respectively), arthrometric testing (P = .045-.99), and time since surgery (P = .592 and .610, respectively).

CONCLUSION

Small amounts of increased intrasubstance graft signal intensity on intermediate- and T2-weighted images can be seen after ACL reconstruction at long-term follow-up of 4 years or longer and do not necessarily correlate with findings of joint instability or functional limitations in patients after ACL repair.

Potential Role of Histone Deacetylase Inhibitors in Mesothelioma: Clinical Experience with Suberoylanilide Hydroxamic Acid

BACKGROUND

Histone deacetylase inhibitors are a novel class of therapeutic agents that inhibit deacetylate histones and other proteins involved in the regulation of gene expression and cell cycle progression. Phase I trials of intravenous and oral formulations of one such agent, vorinostat (suberoylanilide hydroxamic acid [SAHA]), have shown that it is safe and tolerable, that it inhibits histone deacetylation in peripheral blood mononuclear cells, and that it has a broad range of antitumor activity.

PATIENTS AND METHODS

Thirteen patients with mesothelioma were included in a phase I trial of oral SAHA. All but one had previously been treated with chemotherapy.

RESULTS

Four patients completed > or = 6 cycles of therapy; 2 patients demonstrated a partial response. The toxicities in this cohort of patients were similar to those observed in the entire phase I trial: primarily fatigue, dehydration, nausea, and vomiting.

CONCLUSION

Given the dearth of treatment options for patients with advanced mesothelioma who have progressed after first-line chemotherapy, these results are encouraging. A placebo-controlled, randomized phase III study of oral SAHA is now open for patients with mesothelioma in whom treatment with pemetrexed has failed.

Erythroid cell differentiation: murine erythroleukemia cell variant with unique pattern of induction by polar compounds

The murine-virus-infected erythroleukemia cell system provides an opportunity to examine regulatory mechanisms controlling cytodifferentiation. A cloned cell line (DR10c3) resistant to the erythropoiesis-inducing effect of dimethylsulfoxide (Me2SO) was isolated from the Me2SO-sensitive line DS19. DR10c3 is characterized as follows: (1) the uptake of [3H]Me2SO is similar to that in DS19; (2) cell growth with and without Me2SO is similar to that of DS19; (3) resistance is relatively stable; (4) the karyotype of DR10c3 reveals an average loss of five chromosomes per cell, but is otherwise similar to that of DS19; (5) total protein and globin synthesis by cells cultured 4 days with or without Me2SO is similar to these syntheses in DS19 cultured without Me2SO; (6) virtually no globin mRNA is detectable after 3 days in Me2SO, as assayed both by RNA-complementary DNA hybridization and by the heterologous cell-free protein-synthesizing system; (7) other polar compounds, N-methylpyrrolidinone, 1-methyl-2-piperidone, N, N-dimethylacetamide, and N-methylacetamide, induce erythroid differentiation in DR10c3, and the accumulation of alpha- and beta-globin chains is indistinguishable from that in DS19; and (8) the concentration optima for induction of differentiation by all these compounds are identical for DR10c3 and DS19.

Effects of Hylan G-F 20 supplementation on cartilage preservation detected by magnetic resonance imaging in osteoarthritis of the knee: a two-year single-blind clinical trial

BACKGROUND

Although viscosupplementation is an effective symptomatic treatment for knee osteoarthritis (OA), the effect of longer term administration on articular cartilage has not been fully explored. We examined the effect of viscosupplementation with Hylan G-F 20 on knee cartilage over 2 years in patients with knee OA.

METHODS

In this prospective, single-blind, parallel control group pilot study, 78 patients with symptomatic knee OA (Kellgren-Lawrence grade II and III) were assigned to either intervention group (n = 39 receiving 4 courses of 3 × 2.0 ml of intra-articular Hylan G-F 20 injections at 6 month intervals) or control group (n = 39 receiving usual care for knee OA without injections). Magnetic resonance imaging of the study knee was performed at baseline, 12 and 24 months. Cartilage volume and defects were assessed using validated methods.

RESULTS

Fifty-five subjects (71%) completed 24 month follow up. Over 24 months, the intervention group had a reduced annual percentage rate of medial and lateral tibial cartilage volume loss (mean ± SD, -0.3 ± 2.7% and -1.4 ± 4.3%) compared with the control group (2.3 ± 2.6% and 1.4 ± 2.6%, P = 0.001 and 0.005 for difference, respectively). The intervention group also showed reduced cartilage defect score increment in the medial tibiofemoral compartment (0.1 ± 1.3) compared with the control group (0.8 ± 1.5, P = 0.05).

CONCLUSIONS

Six monthly intra-articular injections of Hylan G-F 20 administered to patients with symptomatic knee OA have a beneficial effect on knee cartilage preservation measured by both cartilage volume and cartilage defects. Hylan G-F 20 warrants further evaluation in larger clinical trials as a possible disease-modifying agent in the treatment of knee OA.

TRIAL REGISTRATION

The study was registered with ClinicalTrials.gov (NCT00393393).

Preoperative weight loss with a very-low-energy diet: quantitation of changes in liver and abdominal fat by serial imaging

BACKGROUND

A very-low-energy diet (VLED) can result in substantial, rapid weight loss and is increasingly prescribed before obesity surgery to minimize risk and difficulty by reducing liver size and abdominal adiposity. Despite its growing popularity, a VLED in this setting has received little attention.

OBJECTIVE

The aim of this study was to investigate the efficacy and acceptability of a preoperative VLED.

DESIGN

In a prospective observational study, 32 subjects (n = 19 men and 13 women) with a mean (+/-SD) age of 47.5 +/- 8.3 y and a body mass index (in kg/m(2)) of 47.3 +/- 5.3 consumed a VLED for 12 wk. Primary outcomes included changes in liver volume (LV) and in visceral and subcutaneous adipose tissue (VAT/SAT). Changes in body weight, anthropometric measures, and biochemical variables were also recorded, and compliance with, acceptability of, and side effects of treatment were assessed. Changes in LV and VAT/SAT area were measured by computed tomography and magnetic resonance imaging at baseline and weeks 2, 4, 8, and 12.

RESULTS

Mean (+/-SD) LV, VAT/SAT, and body weight decreased significantly (P < 0.001 for all). The degree of LV reduction was directly related to the reduction in relative body weight (r = 0.54, P = 0.001) and initial LV (r = 0.43, P = 0.015). Eighty percent of the reduction in LV occurred between weeks 0 and 2 (P < 0.001). Reductions in body weight and VAT were uniform over the 12-wk period. Attrition was 14%. Acceptability was adequate but waned over time, and mild transitory side effects occurred.

CONCLUSIONS

Given the observed early reduction in LV and the progressive reduction in VAT, we suggest that the minimum duration for a preoperative VLED be 2 wk. Ideally, the duration should be 6 wk to achieve maximal LV reduction and significant reductions in VAT and body weight without compromising compliance and acceptability.

Patterns and characteristics of hepatitis C transmission clusters among HIV-positive and HIV-negative individuals in the Australian trial in acute hepatitis C

BACKGROUND

Injecting drug users remain the population at greatest risk of acquiring hepatitis C virus (HCV) infection, although a recent increase in cases of sexually transmitted HCV infection has been observed among human immunodeficiency virus (HIV)-infected individuals. The extent to which these separate epidemics overlap is unknown.

METHODS

The Australian Trial in Acute Hepatitis C (ATAHC) enrolled 163 individuals (29% of whom were HIV infected) with recent HCV infection. E1/HVR1 sequences were used to construct phylogenetic trees demonstrating monophyletic clusters or pairs, and viral epidemic history and phylogeography were assessed using molecular clock analysis. Individual clusters were characterized by clinical and demographic characteristics.

RESULTS

Transmission through injection drug use occurred for 73% of subjects, with sexual transmission occurring for 18% (92% of whom were HIV infected). Among 112 individuals with available E1/HVR1 sequences, 23 (20%) were infected with a strain of HCV identical to that of another subject, comprising 4 homologous clusters and 3 monophyletic pairs, the majority of which (78%) were HIV infected. Clusters contained individuals with both injection drug use-related and sex-related acquisition, and in all clusters (except for 1 female HIV-uninfected pair), individuals identified as men who have sex with men, irrespective of HIV status.

CONCLUSIONS

This large unique study of HIV-infected and HIV-uninfected individuals with recently acquired HCV infection demonstrates that clustering is common in the HIV-infected population and that it occurred almost invariably among men who have sex with men, irrespective of the actual mode of acquisition. These findings suggest the coexistence of both injection drug use and sexual risk behaviors for individuals in the same social networks and have implications for the development of public health messages. Clinical trial registration. NCT00192569.

Arthroscopic Bankart repair with the Suretac device. Part I: Clinical observations

Although arthroscopic Bankart repair has become an accepted surgical stabilization technique for anterior shoulder instability, the failure rate remains unacceptably high. Little information is available concerning healing of the Bankart repair. The purpose of this article is to clarify this issue by analyzing a cohort of 15 patients who underwent a "second-look" arthroscopy to evaluate and treat pain or recurrent instability following arthroscopic Bankart repair with the Suretac device (Acufex Microsurgical, Mansfield, MA). "Second-look" arthroscopy was performed at an average of 9 months following the index surgical procedure. The reasons for this second surgery were recurrent instability in 7, pain in 6, and pain and stiffness in 2. In the 7 patients with recurrent instability, the Bankart repair was found to be completely healed in 3 (43%), partially healed in 1 (14%), and had recurred in 3 (43%); however, 6 of 7 were observed to have lax capsular tissue. In 4 of these cases, retrospective review of the index surgical procedure showed that a technical error had been made during the repair. Two cases had biopsy of the repair site on "second-look" at 6 to 8 months, and this showed residual polyglyconate polymer debris surrounded by a histiocytic infiltrate. In the remaining 8 cases with stable shoulders, the Bankart repair had completely healed in 5 cases (62.5%) and partially healed in 3 cases (37.5%). The higher failure rate with this approach compared with open approaches appears to result from improper patient selection and errors in surgical technique. There is some question concerning healing strength of the Bankart repair, although complete healing of the Bankart does not seem to be a prerequesite for shoulder stability. Success of the procedure might be expected to improve by selecting only patients with unidirectional, posttraumatic, anterior instability who are found to have a discrete Bankart lesion and well-developed ligamentous tissue.

Chronic anterior cruciate ligament deficiency. Long-term results of MacIntosh's lateral substitution reconstruction

The lateral substitution reconstruction operation described by MacIntosh has been evaluated in 27 patients with chronic anterior cruciate ligament deficiency of the knee. The results, at an average of 11.3 years after operation, have been assessed by a scoring system which allocates a maximum of 25 points each for function and for clinical evaluation. Emphasis was placed on subjective giving way and objective evidence of a positive anterior drawer sign and a positive lateral pivot shift test. A score of 46 to 50 was classified as excellent, 41 to 46 as fair, and less than 41 was a poor result: 52% scored excellent, 26% fair and 22% were poor. Most of those with poor results had had evidence of osteoarthritis at the time of operation. Despite the recorded scores, no less than 75% of the patients at long-term follow-up were subjectively improved, and able to maintain an active life style.

Electrocardiographic abnormalities in patients with anorexia nervosa

Images

Preventing thromboembolism after myocardial infarction: effect of low-dose heparin or smoking

A trial of low-dose subcutaneous heparin to prevent thromboembolic complications after myocardial infarction was carried out in 78 patients. Of the 37 heparin-treated patients only two (5%) developed evidence of leg vein thrombosis, while 14 (34%) of the 41 controls did so, and five controls developed pulmonary emboli. Leg vein thrombosis developed in 12 (50%) of the 24 controls who did not smoke cigarettes but in only two (13%) of the 17 controls who were cigarette smokers. Non-smokers who have a myocardial infarction should be given low-dose heparin subcutaneously to prevent leg vein thrombosis and pulmonary embolism.

Sonographic and MRI evaluation of the plantar plate: a prospective study

The purpose of this study was to establish the accuracy of ultrasound in the examination of the plantar plate by comparing it with MRI, or if available, surgical findings. The lesser metatarsophalangeal joint plantar plates of 40 symptomatic and 40 asymptomatic feet (160 asymptomatic and 160 symptomatic plantar plates) were examined with ultrasound and MRI. Patients treated with surgery were chosen on a clinical basis and provided surgical correlation for the imaging techniques. Symptomatic patients with metatatarsalgia and suspected metatarsophalangeal joint instability were referred by an orthopedic foot specialist; asymptomatic feet were obtained either through examination of the contralateral foot of the symptomatic patients or volunteers. Ultrasound detected 75/160 and 139/160 plantar plates torn in the asymptomatic and symptomatic groups, respectively. MRI detected 56/160 and 142/160 tears in the symptomatic and asymptomatic groups, respectively. The sensitivity of MRI and ultrasound with surgical correlation was calculated to be 87 and 96%, respectively, with poor specificity. Ultrasound correlates moderately with MRI in the evaluation of the plantar plate. Surgical correlations, although limited (n = 10), indicate ultrasound is superior to MRI with more accurate detection of tears.

Decompression and circumferential stabilization of unstable spinal fractures

A technique of anterior decompression of the spinal canal with anterior strut grafts, followed by posterior instrumentation and local fusion, is described in a group of 18 patients with unstable thoracolumbar fractures. All patients were found to have greater than 50% encroachment of the spinal canal and a preoperative kyphosis of 21.8 degrees. At follow-up 81% of patients with incomplete neurological lesions improved at least one Frankel Grade. Residual encroachment on the spinal canal was 4.6% and at follow-up the kyphotic angle was 17.1 degrees. Complications included one anterior graft loosening (not requiring revision), three loosened rods, only one of which required revision, and one fractured Harrington rod which did not require revision. The authors conclude that this technique is an effective and safe method for treating unstable thoracolumbar injuries and is recommended if anterior instrumentation is unavailable.

Technique for arthroscopic suture fixation of displaced tibial intercondylar eminence fractures

Our modification of the technique for arthroscopic reduction and suture fixation of displaced fractures of the intercondylar eminence of the tibia is described in this report. The advantages of this technique include no retained hardware, ability to treat comminuted (type IV) injuries, and technical simplicity. In combination with a relatively aggressive postoperative rehabilitation program, the treatment of six adults with this technique is described.

A biomechanical analysis of joint contact forces in the posterior cruciate deficient knee

The approach to the posterior cruciate deficient knee is controversial. The purpose of this study is to document the biomechanical changes in the static cadaveric knee model with simulated physiological loads. Nine fresh cadaveric knees from young donors (aged under 45 years) were mounted on a materials testing machine. Loading was carried out at 0 degrees, 30 degrees and 60 degrees to 1.5 kN with low-pressure sensitive Prescale film (Fuji; Tokyo, Japan) inserted through arthrotomies into the medial and lateral compartments. Computerized analysis of the imprints on the film was then carried out. Tests were then repeated after cutting the posterior cruciate ligament (PCL). Results demonstrate a statistically significant posterior subluxation of the tibia on the femur at 60 degrees flexion. This causes a significant increase in contact pressure and pressure concentration on the medial compartment of the knee after cutting the PCL. This may help explain the long-term degenerative changes observed in the medial femoral condyle after cutting the PCL.