Background: Severe and chronic back pain often originates from degenerated intervertebral discs, probably from lesions in the outer posterior anulus. Unlike the nucleus, the outer anulus has a high cell density and adequate metabolite transport. The outer annulus can heal after injury in small and young experimental animals, but little is known about the healing potential of adult human discs.

Purpose: We seek evidence that healing of the human outer anulus follows the three stages of tendon healing: inflammation, repair, remodelling. If so, then manual therapy and self-treatment techniques known to facilitate tendon healing could be adapted to treat discogenic back pain.

Methods: Anulus tissue was removed at surgery (usually posteriorly) from 14 patients with discogenic back pain. Tissue was paraffin embedded and sectioned at 5 μm for histology and immunohistochemistry. Apoptosis was detected using an antibody for caspase-3.

Results: Fissures in the peripheral posterior annulus, and herniated tissue fragments, were associated with blood vessels, inflammatory cells, and with focal loss of proteoglycans. Cell density decreased with distance from fissures from the disc periphery. Overall cell density decreased with age. Apoptosis was greater in the nucleus than in the annulus, and was particularly associated with cell clusters, and with anulus fissures.

Conclusion: These preliminary results suggest an inflammatory healing response in the outer anulus, strongly associated with radial fissures. Loss of proteoglycan from fissure margins may facilitate the ingrowth of capillaries and nerves, which then stimulate local healing in the vicinity of the fissures.

Conflicts of Interest: None

Source of Funding: BackCare

Osteolysis caused by polyethylene wear particles leads to loosening or bone destruction.

Attempts to minimise wear rely largely on selection of the most suitable materials for the purpose. This is typically stainless steel, cobalt chromium or ceramic for the femoral head and primarily polyethylene on the acetabular side. However, there is increased use of both ceramic-on-ceramic and metal-on-metal articulations, particularly in younger patients, and of cross-linked polyethylene in the hip articulation.

Emphasising material selection and development, this paper discusses possible future technical direction of the hip articulation.

Many designs of hip prostheses are available. The rationale for their design is as varied as their shape.

However, the clinical results of these products are in many ways comparable, with similar survivorship at 10 and 15 years. This leads to the question, ‘Does design matter?’.

Looking at such variables as instrument design, cement, surgical technique, and variations that occur naturally among patients, this paper explores this question.