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.

There have been many advances in the resuscitation and early management of patients with severe injuries during the last decade. These have come about as a result of the reorganisation of civilian trauma services in countries such as Germany, Australia and the United States, where the development of trauma systems has allowed a concentration of expertise and research. The continuing conflicts in the Middle East have also generated a significant increase in expertise in the management of severe injuries, and soldiers now survive injuries that would have been fatal in previous wars. This military experience is being translated into civilian practice.

The aim of this paper is to give orthopaedic surgeons a practical, evidence-based guide to the current management of patients with severe, multiple injuries. It must be emphasised that this depends upon the expertise, experience and facilities available within the local health-care system, and that the proposed guidelines will inevitably have to be adapted to suit the local resources.

We performed a retrospective review of all patients admitted to two large University Hospitals in the United Kingdom over a 24-month period from January 2008 to January 2010 to identify the incidence of atypical subtrochanteric and femoral shaft fractures and their relationship to bisphosphonate treatment. Of the 3515 patients with a fracture of the proximal femur, 156 fractures were in the subtrochanteric region. There were 251 femoral shaft fractures. The atypical fracture pattern was seen in 27 patients (7%) with 29 femoral shaft or subtrochanteric fractures. A total of 22 patients with 24 atypical fractures were receiving bisphosphonate treatment at the time of fracture. Prodromal pain was present in nine patients (11 fractures); 11 (50%) of the patients on bisphosphonates suffered 12 spontaneous fractures, and healing of these fractures was delayed in a number of patients. This large dual-centre review has established the incidence of atypical femoral fractures at 7% of the study population, 81% of whom had been on bisphosphonate treatment for a mean of 4.6 years (0.04 to 12.1).

This study does not advocate any change in the use of bisphosphonates to prevent fragility fractures but attempts to raise awareness of this possible problem so symptomatic patients will be appropriately investigated. However, more work is required to identify the true extent of this new and possibly increasing problem.

We examined prospectively collected data from 6782 consecutive hip fractures and identified 327 fractures in 315 women aged ≤65 years. We report on their demographic characteristics, treatment and outcome and compare them with a cohort of 4810 hip fractures in 4542 women aged > 65 years.

The first significant increase in age-related incidence of hip fracture was at 45, rather than 50, which is when screening by the osteoporosis service starts in most health areas. Hip fractures in younger women are sustained by a population at risk as a result of underlying disease. Mortality of younger women with hip fracture was 46 times the background mortality of the female population. Smoking had a strong influence on the relative risk of ‘early’ (≤ 65 years of age) fracture.

Lag screw fixation was the most common method of operative treatment. General complication rates were low, as were re-operation rates for cemented prostheses. Kaplan-Meier implant survivorship of displaced intracapsular fractures treated by reduction and lag screw fixation was 71% (95% confidence interval 56 to 81) at five years. The best form of treatment remains controversial.

We performed a retrospective study of a departmental database to assess the efficacy of a new model of orthopaedic care on the outcome of patients with a fracture of the proximal femur. All 1578 patients admitted to a university teaching hospital with a fracture of the proximal femur between December 2007 and December 2009 were included. The allocation of Foundation doctors years 1 and 2 was restructured from individual teams covering several wards to pairs covering individual wards. No alterations were made in the numbers of doctors, their hours, out-of-hours cover, or any other aspect of standard patient care. Outcome measures comprised 30-day mortality and cause, complications and length of stay. Mortality was reduced from 11.7% to 7.6% (p = 0.007, Cox’s regression analysis); adjusted odds ratio was 1.559 (95% confidence interval 1.128 to 2.156). Reductions were seen in Clostridium difficile colitis (p = 0.017), deep wound infection (p = 0.043) and gastrointestinal haemorrhage (p = 0.033). There were no differences in any patient risk factors (except the prevalence of chronic obstructive pulmonary disease), cause of death and length of stay before and after intervention. The underlying mechanisms are unclear, but may include improved efficiency and medical contact time.

These findings may have implications for all specialties caring for patients on several wards, and we believe they justify a prospective trial to further assess this effect.

We determined the age-specific incidence of a second fracture of the hip and compared it with that of a primary fracture in a study population drawn from 6331 patients admitted to Nottingham University Hospital with a primary fracture of the hip over a period of 8.5 years. The incidence of a second fracture was determined using survival analysis. The mean age-specific incidence rates of primary hip fracture were calculated using census data.

The overall incidence of a second fracture was 2.7% at one year and 7.8% at 8.5 years. That of a primary fracture was 50 per 100 000 in women aged 55 to 64 years rising to 3760 in those aged 84 years and over. The incidence of a second fracture in women aged 55 to 64 years was 2344 per 100 000. Patients of this age had a relative risk of 45 (95% confidence interval 13 to 155) for further fracture when compared with the population at risk of a first fracture. The incidence of a second fracture in women aged > 84 years was 2451 per 100 000 (relative risk 0.7, 95% confidence interval 0.5 to 0.9). A similar trend was seen in men.

Patients sustaining a primary fracture of the hip between the ages of 55 and 64 years have a much greater risk of further fracture than the normal population, whereas those over 84 years have a similar risk. These findings have important implications for the provision of fracture prevention services in primary and secondary care.

Prospective data on hip fracture from 3686 patients at a United Kingdom teaching hospital were analysed to investigate the risk factors, financial costs and outcomes associated with deep or superficial wound infections after hip fracture surgery.

In 1.2% (41) of patients a deep wound infection developed, and 1.1% (39) had a superficial wound infection. A total of 57 of 80 infections (71.3%) were due to Staphylococcus aureus and 39 (48.8%) were due to MRSA.

No statistically significant pre-operative risk factors were detected. Length of stay, cost of treatment and pre-discharge mortality all significantly increased with deep wound infection. The one-year mortality was 30%, and this increased to 50% in those who developed an infection (p < 0.001). A deep infection resulted in doubled operative costs, tripled investigation costs and quadrupled ward costs.

MRSA infection increased costs, length of stay, and pre-discharge mortality compared with non-MRSA infection.