The objective of this study was to compare the effects of soft tissue coverage by either muscle or fasciocutaneous tissue on the healing of open tibial fractures in a murine model. An open tibial fracture, stripped of periosteum with intramedullary fixation, was created in mice. Experimental groups were devised to allow exclusive comparison of either muscle alone or skin plus fascia in direct contact with healing bone. To exclusively assess the relative efficacy of muscle and fasciocutaneous tissue to promote healing of a fracture stripped of periosteum, a piece of sterile inert material (polytetrafluoroethylene) was positioned anteriorly, excluding skin and fascia (muscle group) or posteriorly, excluding muscle (fasciocutaneous group). Skeletal repair was assessed histologically and quantified by histomorphometry; quantitative peripheral computed tomography (pQCT) and mechanical testing using a four-point bending technique. This standardized, reproducible model allowed characterization of the morphology of open fracture healing. At 28 days postfracture, there was faster healing in the experimental muscle coverage group compared to skin and fascia alone. Furthermore, there was almost 50% more cortical bone content and a threefold stronger union beneath muscle compared to fasciocutaneous tissue (p < 0.05 by one-way ANOVA). Exclusive comparison of muscle and fasciocutaneous tissue in our novel murine model demonstrates that muscle is superior for the coverage of open tibial fractures for both the rate and quality of fracture healing. ß

Osteonecrosis of the femoral head usually affects young individuals and is responsible for up to 12% of total hip arthroplasties. The underlying pathophysiology of the death of the bone cells remains uncertain. We have investigated nitric oxide mediated apoptosis as a potential mechanism and found that steroid- and alcohol-induced osteonecrosis is accompanied by widespread apoptosis of osteoblasts and osteocytes. Certain drugs or their metabolites may have a direct cytotoxic effect on cancellous bone of the femoral head leading to apoptosis rather than purely necrosis.

Although it is widely accepted that grade IIIB open tibial fractures require combined specialised orthopaedic and plastic surgery, the majority of patients in the UK initially present to local hospitals without access to specialised trauma facilities. The aim of this study was to compare the outcome of patients presenting directly to a specialist centre (primary group) with that of patients initially managed at local centres (tertiary group). We reviewed 73 consecutive grade IIIB open tibial shaft fractures with a mean follow-up of 14 months (8 to 48). There were 26 fractures in the primary and 47 in the tertiary group. The initial skeletal fixation required revision in 22 (47%) of the tertiary patients. Although there was no statistically-significant relationship between flap timing and flap failure, all the failures (6 of 63; 9.5%) occurred in the tertiary group. The overall mean time to union of 28 weeks was not influenced by the type of skeletal fixation. Deep infection occurred in 8.5% of patients, but there were no persistently infected fractures. The infection rate was not increased in those patients debrided more than six hours after injury. The limb salvage rate was 93%. The mean limb functional score was 74% of that of the normal limb. At review, 67% of patients had returned to employment, with a further 10% considering a return after rehabilitation. The times to union, infection rates and Enneking limb reconstruction scores were not statistically different between the primary and tertiary groups. The increased complications and revision surgery encountered in the tertiary group suggest that severe open tibial fractures should be referred directly to specialist centres for simultaneous combined management by orthopaedic and plastic surgeons.

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The authors' data show that the more advanced healing of fractures covered by muscle compared with fasciocutaneous tissue is not related to the vascularity of the tissues, as the latter had a higher vascular density at all time points. Therefore, provided that a flap has sufficient vascularity to effectively reconstitute the soft-tissue envelope, other factors may be important in specifically promoting fracture healing.

This study demonstrates that a systemised trauma network combined with evidence based practice can lead to improvements in patient care.

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Our aim was to assess the local extent of osteocyte death in the proximal femur of 16 patients with osteonecrosis of the femoral head. We performed histological examination of the femoral heads and cancellous bone biopsies from four regions of the proximal femur in patients undergoing total hip arthroplasty. A control group consisted of 19 patients with osteoarthritis. All histological specimens were examined in a blinded fashion. Extensive osteonecrosis was shown in the proximal femur up to 4 cm below the lesser trochanter in the group with osteonecrosis. There was an overall statistically significant difference in the extent of osteocyte death distal to the femoral head between the two groups (p < 0.001). We discuss the implications of these findings as possible contributing factors in regard to the early failure of total hip arthroplasty reported in patients with osteonecrosis of the femoral head.