It has been proposed that intervertebral disc degeneration might be caused by low-grade infection. The purpose of the present study was to assess the incidence of herpes viruses in intervertebral disc specimens from patients with lumbar disc herniation. A polymerase chain reaction based assay was applied to screen for the DNA of eight different herpes viruses in 16 patients and two controls. DNA of at least one herpes virus was detected in 13 specimens (81.25%). Herpes Simplex Virus type-1 (HSV-1) was the most frequently detected virus (56.25%), followed by Cytomegalovirus (CMV) (37.5%). In two patients, co-infection by both HSV-1 and CMV was detected. All samples, including the control specimens, were negative for Herpes Simplex Virus type-2, Varicella Zoster Virus, Epstein Barr Virus, Human Herpes Viruses 6, 7 and 8. The absence of an acute infection was confirmed both at the serological and mRNA level.

To our knowledge this is the first unequivocal evidence of the presence of herpes virus DNA in intervertebral disc specimens of patients with lumbar disc herniation suggesting the potential role of herpes viruses as a contributing factor to the pathogenesis of degenerative disc disease.

We reviewed the outcome of 28 patients who had been treated using the Aequalis fracture prosthesis for an acute fracture of the proximal humerus at a mean follow-up of 39.3 months (24 to 63). The mean age of the patients at the time of the fracture was 66.3 years (38 to 80). The mean Constant score was 68.2 (37 to 84) for the operated shoulder, which represented 89.5% of the mean score for the uninjured side (p < 0.001). The quality of the reconstruction as shown on the immediate post-operative radiographs was categorised into three types, anatomical, acceptable, and unacceptable, depending on the position of the tuberosities relative to the prosthetic head and the humeral shaft. Anatomical reconstruction was associated with a higher mean Constant score as well as higher mean values of anterior forward elevation, abduction and external rotation than the other types, but the differences were not statistically significant (p > 0.231).

A total of 18 patients had active anterior elevation ≥150°. Their mean active abduction and external rotation were 163.6° and 31.3°, respectively. In seven of the 28 patients, the mean active anterior elevation, abduction and external rotation were 130.7°, 129.2° and 22.8°, respectively. In all, 12 patients were very satisfied with the results, 12 were satisfied, two were dissatisfied and two were disappointed; 26 reported no or only mild pain while only two had moderate pain. In five patients proximal migration of the humeral head was shown on the anteroposterior radiographs of the shoulder. No evidence of loosening was found in any prosthesis.

The pathophysiology of intervertebral disc degeneration has been extensively studied. Various factors have been suggested as influencing its aetiology, including mechanical factors, such as compressive loading, shear stress and vibration, as well as ageing, genetic, systemic and toxic factors, which can lead to degeneration of the disc through biochemical reactions. How are these factors linked? What is their individual importance? There is no clear evidence indicating whether ageing in the presence of repetitive injury or repetitive injury in the absence of ageing plays a greater role in the degenerative process. Mechanical factors can trigger biochemical reactions which, in turn, may promote the normal biological changes of ageing, which can also be accelerated by genetic factors. Degradation of the molecular structure of the disc during ageing renders it more susceptible to superimposed mechanical injuries.

This review supports the theory that degeneration of the disc has a complex multifactorial aetiology. Which factors initiate the events in the degenerative cascade is a question that remains unanswered, but most evidence points to an age-related process influenced primarily by mechanical and genetic factors.