Introduction: Modular prostheses were first developed for use in total hip arthroplasty (THA) in the 1980s as a potential solution to the problem of leg length inequality. There is much literature discussing the advantages and disadvantages of modularity in THA but there are few studies directly comparing modular and non-modular prostheses and their accuracy in restoring normal anatomy. Our aim was to assess whether modularity in THA improves the restoration of femoral offset and leg length.

Methods: An analysis of post-operative radiographs of 76 patients who underwent THA - 38 using modular and 38 using non-modular prostheses was undertaken. The femoral offset and leg length of the operated and un-operated hip were measured for each patient. Inter-and intra-observer errors were reduced to a minimum. A two-tailed T test was then applied to the data.

Results: Restoration of leg length (to within +/− 10mm of the un-operated hip) was achieved in 81.6% of patients in the non-modular group, compared to 78.9% in the modular group (p=0.60). On average, the modular system increases leg length of the operated hip by 0.64mm compared to the non-modular system, which reduces leg length by 3.76mm (p=0.016). The femoral offset is restored to within 5mm of the un-operated hip in 60.5% of modular THA and in 55.3% using a non-modular prosthesis (P=0.48). On average, modular prostheses increased offset by 0.85mm and non-modular prostheses by 0.15mm (P=0.64).

Discussion: The modular and non-modular hip prostheses are equally successful in achieving restoration of leg length and femoral offset to the pre-pathological state.

Introduction: Influence of beta-blockers against fracture is controversial. Role of beta-blockers in fracture treatment not explored.

Objective: to analyze influence of propranolol, a beta-blocker, on fracture healing in a mouse model.

Materials and Methods: Fracture and intramedullary nailing on right femur of 8 week, male C57BL/6 mice. Daily propranolol in drinking water: 0 (control), 4 (low dose) and 20 (high dose) mg/kg 3 week: microcomputed tomography (microCT), histological analyses 6 week: microCT, mechanical testing N = 5 üC 9/group Statistics: two-way ANOVA. Á = 0.05.

Results: From 3 to 6 weeks, callus volume and bone mineral content (BMC) decreased, and tissue mineral density increased significantly in control groups. Callus volume and BMC decreased significantly in low dose groups. No significance in high dose groups. No significance with treatment. At 3 weeks, callus area and woven bone percentage not different with treatment. At 6 weeks, ultimate torque not different with treatment or fracture. Within the control groups, twist at ultimate torque significantly lower in fractured bones. Torsional rigidity increased significantly in fractured bones, but not different with treatment.

Discussion: Most studies based on population observation or manipulation of sympathetic signaling using intact animal bones. The current fracture model may have created neural damage, thereby interrupting the sympathetic pathway and negating its regulation of bone metabolism. Whether neural signaling is compromised by fracture treatment requires further study and may be critical to the action of beta-blockers in bone.