Introduction

Segmental tibia fractures are high-energy injuries that are difficult to treat. We report on the use of the Ilizarov Method to treat 40 consecutive AO 4.2C (35) and AO 4.2B3 (5) fractures by a single surgeon. Fractures with bone loss requiring transport were excluded, as were fractures initially treated with nail or plate. Patients: 28 adult males, 12 adult females, mean age 43. The most common mechanism of injury was RTA (50%). Twelve patients (30%) had associated injuries. Nineteen (48%) fractures were open (6 Gustillo-Anderson 3A, 13 Gustillo-Anderson 3B) and 21 closed; 24 (60%) had temporary monolateral external fixation before definitive treatment. The mean time from injury to definitive Ilizarov frame was 8 days.

Studies on soil mechanics have established that when vibration is applied to an aggregate, it results in more efficient alignment of particles and reduces the energy required to impact the aggregate. Our aim was to develop a method of applying vibration to the bone impaction process and assess its effect on the mechanical properties of the impacted graft.

Phase 1. Eighty bovine femoral heads were milled using the Noviomagus bone mill. The graft was then washed using a pulsed lavage normal saline system over a sieve tower. A vibration impaction device was developed which housed two 15V DC motors with eccentric weights attached inside a metal cylinder. A weight was dropped onto this from a set height 72 times so as to replicate the bone impaction process. A range of frequencies of vibration were tested, as measured using an accelerometer housed in the vibration chamber. Each shear test was then repeated at four different normal loads so as to generate a family of stress-strain curves. The Mohr-Coulomb failure envelope from which the shear strength and interlocking values are derived was plotted for each test.

Phase 2. Experiments were repeated with the addition of blood so as to replicate a saturated environment as is encountered during operative conditions.

Relatively dry graft impacted with the addition of vibration showed improved shear strength at all frequencies of vibration when compared to impaction without vibration. In our system the optimal frequency of vibration was 60 Hz. Under saturated conditions the addition of vibration is detrimental the shear strength of the aggregate. This is secondary to decreased interlocking between particles and may be explained by the process of liquefaction.

Introduction

Total disc replacement (TDR) provides an alternative to fusion that is designed to preserve motion at the treated level and restore disc height. The effects of TDR on spine biomechanics at the treated and adjacent levels are not fully understood. Thus, the present study investigated facet changes in contact pressure, peak contact pressure, force, peak force, and contact area at the facet joints after TDR.

To assess the efficacy of a combined orthoplastic approach to the management of severe grade III fractures of the lower limb, we looked at the functional and radiological outcome of 100 consecutive fractures from a specialist centre.

A prospective analysis was performed on 100 consecutive open tibial fractures (98 patients). An early decision was made by a specialist multidisciplinary team as to whether the injured limb was reconstructable.

In the reconstruction group there were 84 Gustilo grade IIIB/C injuries. Definitive skeletal stabilisation was most commonly with a circular frame (60%) or intramedullary nail (20%). The mean time to union was 26 weeks for diaphyseal fractures, 20 weeks for metaphyseal fractures and 10 weeks for ankle fractures. There was one aseptic non-union which is still undergoing treatment. The anterolateral thigh free flap was the most common soft tissue reconstruction used (42%). There were minimal surgical complications and only one free flap failure. Mean time to follow-up was 24 months. The mean limb functional score (modified enneking) was 83% of that of the normal limb and was not influenced by the site of fracture or type of fixation. The mean SF-36 score was 75 and there was a high return to employment (70%).

In the primary amputation group there were 16 grade IIIB/C injuries. Mean time to follow-up was 38 months. The mean SF-36 score for the below knee amputees was 58 and there was again a high return to employment (58%).

In the reconstruction group there is a 99% limb salvage rate with infection-free union to date and no delayed amputations. A higher return to functional activity/employment was achieved in the reconstruction group compared to the primary amputation group. Our results demonstrate that by using a combined orthoplastic approach in a specialist centre excellent results can be achieved for all patients presenting with severe open lower limb injuries.