A unified theory of bone healing and nonunion: BHN theory.

This article presents a unified clinical theory that links established facts about the physiology of bone and homeostasis, with those involved in the healing of fractures and the development of nonunion. The key to this theory is the concept that the tissue that forms in and around a fracture should be considered a specific functional entity. This 'bone-healing unit' produces a physiological response to its biological and mechanical environment, which leads to the normal healing of bone. This tissue responds to mechanical forces and functions according to Wolff's law, Perren's strain theory and Frost's concept of the "mechanostat". In response to the local mechanical environment, the bone-healing unit normally changes with time, producing different tissues that can tolerate various levels of strain. The normal result is the formation of bone that bridges the fracture - healing by callus. Nonunion occurs when the bone-healing unit fails either due to mechanical or biological problems or a combination of both. In clinical practice, the majority of nonunions are due to mechanical problems with instability, resulting in too much strain at the fracture site. In most nonunions, there is an intact bone-healing unit. We suggest that this maintains its biological potential to heal, but fails to function due to the mechanical conditions. The theory predicts the healing pattern of multifragmentary fractures and the observed morphological characteristics of different nonunions. It suggests that the majority of nonunions will heal if the correct mechanical environment is produced by surgery, without the need for biological adjuncts such as autologous bone graft. Cite this article: Bone Joint J 2016;98-B:884-91.

Acetabular surgical units: a directory for the United Kingdom.

We present the first directory of the specialist acetabular surgical units throughout the United Kingdom. Previously there has not been any directory of acetabular surgeons in the UK as held by any governmental or healthcare agency. We have established that acetabular fracture fixation cases were performed at 33 NHS hospitals in the UK in 2003-2004. The total number of cases performed at each centre per year varied greatly (range 2-98). Twenty-one units performed greater than 10 cases per annum, comprising 92% of all operative cases in the UK in 2003-2004. We encourage trauma and orthopaedic units to communicate directly with their local units and familiarise themselves with those units' preferred referral processes. We publish this directory to assist in future research in this field, to help in resource planning in the field of major trauma, to aid training and continued development in this complex area and help with the timely referral of injured patients to these specialist units for this significant injury.

Sacral fracture associated with small bowel entrapment: a case report.

We report the third documented case of small bowel entrapment within a sacral fracture leading to small bowel obstruction. This important diagnosis is rare and difficult to make, even with current imaging methods. We report a case in which a segment of small bowel trapped in a Denis II fracture of the sacrum required laparotomy, small bowel resection, and an omental patch over the fracture site. In this case the outcome was favorable with no residual sequelae.

Bilateral fracture dislocation of the sacroiliac joint.

We present a rare case of a 27-year-old man sustaining a bilateral fracture dislocation of the sacroiliac joints without disruption of the anterior pelvis, following a fall from a height. Reconstructed images in the coronal plane and three-dimensional CT images were invaluable in the diagnosis and assessment of this injury.

Tension hydropneumothorax as delayed presentation of traumatic rupture of the diaphragm.

Diaphragmatic rupture due to blunt trauma is well recognised though uncommon. Most cases are diagnosed at the time of injury, but a proportion remain undiagnosed, only to present some months or even years later. This "delayed" group can present in a number of ways, including chronic abdominal and chest problems or an acute crisis. Herniation of abdominal viscera is the most common sequel, with strangulation and gangrene as the most serious complication. This paper reports a case of delayed presentation of diaphragmatic rupture and herniation presenting as tension hydropneumothorax due to small bowel perforation. A short discussion addresses the problems in diagnosis of this condition. We believe this to be the first reported case of perforated small bowel leading to tension hydropneumothorax.

Comparative auditory toxicity of aminoglycoside antibiotics in leukopenic patients.

The incidence of auditory toxicity resulting from therapy with ticarcillin (T) (12 g/sq m/day) in combination with gentamicin (G) (200 mg/sq m/day), amikacin (A) (600 mg/dq m/day), or netilmicin (N) (280 mg/sq m/day) was compared. Before administration of these antibiotic combinations to febrile, granulocytopenic patients, baseline audiograms were determined by a pharmacist using a portable audiometer. The before-therapy audiograms for 32 patients receiving T and G, 29 receiving T and A, and 29 receiving T and N were compared with the audiograms after the completion of therapy. The mean length of therapy was seven days. Two patients (6.2%) receiving T and G, one (3.4%) receiving T and N, and one (3.4%) receiving T and A developed auditory toxicity with bilateral decreases of at least 20 decibels at one or more frequencies. The incidence of auditory toxicity secondary to aminoglycoside exposure was low, and the relative auditory toxicity among the three aminoglycosides appeared to be similar.

Randomized trial of empiric antibiotic therapy with ticarcillin in combination with gentamicin, amikacin or netilmicin in febrile patients with granulocytopenia and cancer.

A randomized trial of ticarcillin plus gentamicin (group 1), ticarcillin plus amikacin (group 2) and ticarcillin plus netilmicin (group 3) as empiric antibiotic therapy in patients with granulocytopenia and cancer was carried out at the Baltimore Cancer Research Center. The response rate for all infections was 97 per cent in group 1, 91 per cent in group 2 and 95 per cent in group 3. Patients with bacteremias showed improvement in 93 per cent (group 1), 78 per cent (group 2) and 82 per cent (group 3) of cases. All failures were among patients with gram-negative bacteremias. Both antibiotic susceptibility of the bacteremic organism and granulocyte recovery correlated with patient improvement. Nephrotoxicity and ototoxicity were rare and were not significantly different in three groups of patients. Therefore, ticarcillin plus gentamicin, ticarcillin plus amikacin and ticarcillin plus netilmicin appear to be equally efficacious and minimally toxic in this patient population. Excellent over-all results can be expected with these combinations provided the etiologic agent is susceptible.

Infection in acute leukemia patients receiving oral nonabsorable antibiotics.

During a 20-month period all acute nonlymphocytic patients (87 patient trials) receiving cytotoxic chemotherapy were placed on an oral nonabsorbable antibiotic regimen consisting of gentamicin, vancomycin, and nystatin in addition to an intensive program of infection prevention aimed at reducing exogenously acquired and body-surface potential pathogens. Although side effects of anorexia, diarrhea, and nausea were common, gentamicin-vancomycin-nystatin was ingested 80% of the study time. Microbial growth in gingival and rectal cultures was substantially reduced. The incidence of bacteremias and other serious infections was low. Pseudomonas aeruginosa, other gram-negative bacilli, and Candida species caused few infections along the alimentary canal, whereas infections of the skin (especially Staphylococcus aureus) were not reduced compared with those occurring in former years. A total of the 104 acquired gram-negative bacilli were gentamicin resistant; 5 subsequently caused infection. Thus, despite certain definite drawbacks, the use of oral nonabsorbable antibiotics to suppress alimentary tract microbial flora in combination with other infection prevention techniques in granulocytopenic cancer patients has proven feasible and tolerable and has been associated with a low order of life-threatening infections.

Amikacin and cephalothin: empiric regimen for granulocytopenic cancer patients.

Amikacin (15 mg/kg per day) was used in combination with cephalothin (7 g/m(2) per day) as an empiric regimen for de novo febrile (>101 degrees F [38.3 degrees C]) episodes in 93 granulocytopenic (<1,000/mm(3)) cancer patients. Both drugs were given intravenously in four equal doses every 6 h. The response rate for all documented infections was 83%, including 11 of 17 (65%) bacteremias. Escherichia coli (14 cases) was the most common pathogen, whereas Pseudomonas aeruginosa (2 cases) caused fewer infections. Mean amikacin serum levels were 8.7 mug/ml at 1 h and 2.2 mug/ml at 5 h. Failure of bone marrow recovery in association with a bacteremia was a bad prognostic sign (only two of eight improving). Ototoxicity occurred in two (2%) patients, whereas presumed antibiotic-induced nephrotoxicity developed in six (7%) patients. Surveillance cultures (nose, gums axilla, and rectum) of all hospitalized patients revealed no significant change in the incidence of amikacin resistance. The combination of amikacin and cephalothin in this dose and schedule was safe and efficacious in these granulocytopenic patients.

Ticarcillin in combination with cephalothin or gentamicin as empiric antibiotic therapy in granulocytopenic cancer patients.

Ticarcillin was used in combination with either cephalothin or gentamicin as initial empiric antibiotic therapy for 127 patient trials of suspected infection in granulocytopenic cancer patients. Bacteremia was present in 20%, nonbacteremic microbiologically documented infections in 21%, clinically documented infections in 23%, and possible infections in 5%; infection was doubtful in 31%. Although Staphylococcus aureus was the most common single organism isolated (23%), gram-negative bacilli accounted for 54% of all pathogens. Both antibiotic regimens were highly efficacious, with complete resolution in 46% of bacteremias, 88% of nonbacteremic microbiologically documented infections, and 95% of clinically documented infections. Among bacteremias, 8 of 9 caused by S. aureus but only 4 of 15 (27%) caused by gram-negative bacilli were completely resolved with these antibiotic combinations. Reasons for nonresponse in bacteremias were persistent granulocytopenia, mixed infection and, in two patients, antibiotic-resistant organisms. Toxicities other than hypokalemia were minimal. Although the rate of further infections was high overall (18/127), only one occurred among the 39 patients with <4 days of antibiotic therapy. Ticarcillin in combination with either cephalothin or gentamicin was effective as initial empiric therapy of suspected infection in granulocytopenic cancer patients.