Introduction: Epidemiology suggests that an intrauterine nutrient restriction increases the likelihood of osteoporosis in later life, possibly due to differences in bone structure and strength. We hypothesise that, in an ovine model, early nutritional compromise reduces vertebral cancellous bone density and cortical thickness, and thereby reduces vertebral compressive strength.

Materials and methods: Lumbar spines were dissected from 8 sheep (6 male, 2 female: mean age 2.7 yrs). Spines were divided into different groups, based on the early diet of the sheep: group CC received a control diet, group IU received low protein in utero, and group PN received low protein both in utero and postnatally. Fifteen motion segments (consisting of two vertebrae and the intervening disc and ligaments) were prepared from the spines, and compressed to failure using a hydraulically-controlled materials testing machine to obtain yield strength. 1mm-thick bone slices were taken from the mid-sagittal and para-sagittal regions of each vertebral body and micro-radiographed. Digital images of the micro-radiographs were analysed to obtain the cancellous bone density in anterior and posterior regions, and the cortical thickness in the anterior, posterior, superior and inferior regions. Repeated measures ANOVA was used to test for differences in parameters at the different locations, and between the groups.

Results: The anterior cortex was 28% thinner for the IU group, and 23% thinner for the PN group compared to controls (both p< 0.001). In the PN group, the superior cortex was also 18% thinner than controls (p< 0.02). There was no significant difference between cancellous bone density in either region. Yield strength was 16% lower in the IU group compared to controls, but this did not reach significance.

Discussion: In the nutritionally compromised groups, cortical thickness was lower in regions of the vertebral body where fractures often occur in elderly people. However, the reduction in cortical thickness is not accompanied by a significant reduction in compressive strength in the sheep model. These findings suggest that the well-maintained cancellous bone protects the vertebra from fracture.

Introduction Comminuted intra-articular fractures of the distal radius are severe injuries where the outcome depends on accurate anatomical reduction and reconstitution of the articular surface, and early mobilisation. This prospective outcome study aims to assess the anatomical and functional outcome of internal fixation of these complex fractures using a fragment specific fixation system.

Methods Fifty consecutive comminuted intra-articular distal radius fractures presenting at our hospital were treated by the one surgeon (MP). Inclusion criteria were age under 80 and AO classification C-3. Various combinations of wires, buttress pins/clips and plates were utilized according to each fracture configuration. No post-op splintage was used. All patients commenced hand therapy from day one post-op. Patients were reviewed at two weekly intervals till fracture union and monthly thereafter. All patients were independently assessed by a hand therapist for range of motion and grip strength. Patient function was assessed using the DASH (Disabilities of the Arm, Shoulder and Hand) and the PRWE scores. Thirteen males and 37 female with an average age of 53.8 (29 to 72) were treated with the TriMed between February 2002 and February 2003. Average follow-up was seven months (3 to 14).

Results All fractures had healed at the six week review, with mean palmar tilt of 12°, radial tilt of 19° and radioulnar variance of 5 mm, with articular step less than 1 mm. The mean DASH score was 19 (SD 9) and mean PRWE score was 19 (SD 11). Average range-of-motion was 65 (SD 17) dorsi-flexion, 55 (SD 19) palmar-flexion, 73 pronation and 67 supination. Grip strength recovered to 85% on average when compared to the opposite hand. There were no deep or superficial wound infections. Three patients had difficulty regaining early hand function, with difficulty complying with physiotherapy. One had borderline mental retardation. Two displayed symptoms of RDS, one responding to medication, and one requiring guanethidine arm block.

Conclusions Intra-articular distal radius fractures can be reliably and anatomically reduced and stabilized using fragment-specific fixation. Fixation of markedly comminuted fractures is secure enough to allow immediate motion. Clinical and radiographic results are excellent, and patient satisfaction is high. Patient compliance with hand therapy is critical for a good functional result.