Surgical anatomy for pelvic external fixation.

Pelvic external fixators have a high rate of reported complications, most of which relate to pin placement. In this descriptive study, we analyzed the morphology of the ilium in cadaveric specimens and compared these with the measures obtained from normal human pelvic computer tomograph scans, and how these related to each of the three basic configurations of pin positioning for the external fixation of a pelvis: anterosuperior (Slätis type), anteroinferior (supra-acetabular), and subcristal. The irregular shape and size of the iliac wing and the abdominal wall overlying the pin's insertion site could hinder accurate placement of anterosuperior pins. Potential disadvantages of the use of anteroinferior pins was found related to the deep location of the anterior inferior iliac spine, interference with the hip flexion area, risk of hip joint penetration, and the variable obliquity of the ilium. As subcristal pins are positioned between two superficial bony landmarks of the iliac crest, our findings suggest that they are more likely to have a correct placement and avoid complications.

Abduction strength following intramedullary nailing of the femur.

OBJECTIVES: To assess hip abductor function, strength and complaints following insertion of a femoral intramedullary nail. DESIGN: Retrospective clinical review. SETTING: Department of Orthopaedics, Adelaide Women's and Children's Hospital, Adelaide. Department of Orthopaedic Surgery and Trauma, Royal Adelaide Hospital, Adelaide, South Australia, Australia. PATIENTS: 1. 32 of 37 patients who had an intramedullary nail inserted for an isolated femoral shaft fracture at the Royal Adelaide Hospital between 1987 and 1990. 2. 14 of 18 patients who had closed femoral shortening for leg length discrepancy, at the Adelaide Women's and Children's Hospital between 1985 and 1987. Patients with pathology involving the abductor mechanism were excluded. 3. 40 asymptomatic controls. INTERVENTION: Intramedullary fixation for femoral shaft fractures or as part of closed femoral shortening. All procedures were performed on a traction table via a gluteal splitting approach with reamed nails. MAIN OUTCOME MEASUREMENTS: Complaints included, pain, stiffness, limp and diminished walking distance. Examination of abductor function and measurement of abductor strength. Radiological assessment at followup. RESULTS: Complaints included trochanteric pain (40%, 40%), thigh pain (10%, 8%) and limp (13%, 42%) in the femoral fracture and closed femoral shortening groups respectively. There was significant difference in the abduction strength (p < 0.01) and abduction ratio (p < 0.01) between the control and each treatment group. Abductor weakness correlated (r = 0.30) with the incidence of complaints. CONCLUSION: Pain, limp and weakness are common following insertion of a femoral intramedullary nail. Agluteal retracting approach may minimize abductor weakness.

Clinical implications of stiffness and strength changes in fracture healing.

In the assessment of fracture healing by monitoring stiffness with vibrational analysis or instrumented external fixators, it has been assumed that there is a workable correlation between stiffness and strength. We used four-point bending tests to study time-related changes in stiffness and strength in healing tibial fractures in sheep. We aimed to test the validity of the measurement of stiffness to assess fracture strength. At each duration of healing examined, we found marked variations in stiffness and strength. Stiffness was shown to be load-dependent: measurements at higher loads reflected ultimate strength more accurately. There was a biphasic relationship between stiffness and strength: at first there was a strong correlation regardless of loading conditions, but in the second phase, which included the period of 'clinical healing', stiffness and strength were not significantly correlated. We conclude that the monitoring of stiffness is useful primarily in assessing progress towards union but is inherently limited as an assessment of strength at the time of clinical union. Any interpretation of stiffness must take into account the load conditions.

Biochemical and physiological changes in football players.

Twenty-three football players were studied before and after a match to assess if intermittent exertion produced the same biochemical and physiological changes noted in marathon runners. All players developed a significant fluid deficit and rise in body temperature despite ready access to water. However, the changes were less marked than those described in runners. They also showed acidosis, a rise in serum levels of creatinine, urate and urea and striking elevations in the levels of creatine kinase and other enzymes. Serum magnesium levels fell, as did those of potassium; this is not the case in runners, in whom hyperkalaemia is more frequently described.