Aims

Computer hexapod assisted orthopaedic surgery (CHAOS), is a method to achieve the intra-operative correction of long bone deformities using a hexapod external fixator before definitive internal fixation with minimally invasive stabilisation techniques.

The aims of this study were to determine the reliability of this method in a consecutive case series of patients undergoing femoral deformity correction, with a minimum six-month follow-up, to assess the complications and to define the ideal group of patients for whom this treatment is appropriate.

Percutaneous grafting of non-union using bone marrow concentrates has shown promising results, we present our experience and outcomes following the use of microdrilling and marrowstim in long bone non-unions.

We retrospectively reviewed all patients undergoing a marrowstim procedure for non-union in 2011–12. Casenotes and radiographs were reviewed for all. Details of injury, previous surgery and non-union interventions together with additional procedures performed after marrowstim were recorded for all patients. The time to clinical and radiological union were noted.

We identified 32 patients, in sixteen the tibia was involved in 15 the femur and in one the humerus. Ten of the 32 had undergone intervention for non-union prior to marrowstim including 4 exchange nailings, 2 nail dynamisations, 3 caption graftings, 2 compression in circular frame and 1 revision of internal fixation. Three underwent adjunctive procedures at the time of marroswstim. In 18 further procedures were required following marrowstim. In 4 this involved frame adjustment, 5 underwent exchange nailing, 4 revision internal fixation, 2 additional marrowstim, 2 autologous bone grafting and 3 a course of exogen treatment.

In total 27 achieved radiological and clinical union at a mean of 9.6 months, of these ten achieved union without requiring additional intervention following marrowstim, at a mean of 5.4 months. There were no complications relating to marrowstim harvest or application.

Marrowstim appears to be a safe and relatively cheap addition to the armamentarium for treatment of non-union. However many patients require further procedures in addition to marrowstim to achieve union. Furthermore given the range of procedures this cohort of patients have undergone before and after marrowstim intervention it is difficult to draw conclusions regarding it efficacy.

Lower limb mal-alignment due to deformity is a significant cause of early degenerative change and dysfunction. Standard techniques are available to determine the centre of rotation of angulation (CORA) and extent of the majority of deformities, however distal femoral deformity is difficult to assess because of the difference between anatomic and mechanical axes. We found the described technique involving constructing a line perpendicular to a line from the tip of the greater trochanter to the centre of the femoral head inaccurate, particularly if the trochanter is abnormal. We devised a novel technique which accurately determines the CORA and extent of distal femoral deformity, allowing accurate correction.

Using standard leg alignment views of the normal femur, the distal femoral metaphysis and joint line are stylized as a block. A line bisecting the axis of the proximal femur is then extended distally to intersect the joint. The angle (θ) between the joint and the proximal femoral axis and the position (p) where the extended proximal femoral axis intersects the joint line are calculated. These measurements can then be reproduced on the abnormal distal femur in order to calculate the CORA and extent of the deformity, permitting accurate correction.

We examined the utility and reproducibility of the new method using 100 normal femora. θ = 81 ± sd 2.5°. As expected, θ correlated with femoral length (r=0.74). P (expressed as the percentage of the distance from the lateral edge of the joint block to the intersection) = 61% ± sd 8%. P was not correlated with θ.

Intra-and inter-observer errors for these measurements are within acceptable limits and observations of 30-paired normal femora demonstrate similar values for θ and p on the two sides.

We have found this technique to be universally applicable and reliable in a variety of distal femoral deformities.

Lower limb mal-alignment due to deformity is a significant cause of early degenerative change and dysfunction. Standard techniques are available to determine the centre of rotation of angulation (CORA) and extent of the deformities. However, distal femoral deformity is difficult to assess because of the difference between anatomic and mechanical axes. We describe a novel technique which accurately determines the CORA and extent of distal femoral deformity.

Using standard leg alignment views of the normal femur, the distal femoral metaphysis and joint line are stylised as a block. A line bisecting the anatomical axis of the proximal femur is then extended distally to intersect the joint. The angle (?) between the joint and the proximal femoral axis, and the position (p) where the extended proximal femoral axis intersects the joint line are calculated. These measurements can then be reproduced on the abnormal distal femur in order to calculate the CORA and extent of deformity, permitting accurate correction.

We examined the utility and reproducibility of the new method using 100 normal femora. We found this technique to be universally robust in a variety of distal femoral deformities.

Introduction

The optimal management of intra-articular tibial plateau fractures with metaphyseal-diaphyseal dissociation remains challenging and controversial. We report results using the technique of limited open reduction with external fixation using a fine wire circular frame.

Simultaneous arthrodesis of the ankle and subtalar joints is an established treatment option for combined ankle and subtalar arthritis or complex hindfoot deformities. The use of a curved intra medullary nail has potential advantages in terms of stability, hindfoot alignment and avoidance of the lateral neurovascular bundle.

We devised a comparative description of the results of hindfoot fusion using a curved locking nail before and after the introduction of anatomically specific modifications to the device through a retrospective review of notes and radiographs of patients undergoing simultaneous ankle and subtalar fusion by retrograde intramedullary nailing using an ACE¯ (Humeral Nail. Patients undergoing the same procedure using the Tibiotalocalcaneal [TTC] Nail System [DePuy] were recruited and studied prospectively. The outcome was assessed by a combination of notes review, clinical examination and telephone questionnaire.

Between 1996 and 2004, 71 arthrodeses in 67 patients have been performed. The average follow up is 27 months [3-73] and mean age 58 years. Fifty-two arthrodeses utilised the ACE humeral nail and nineteen used the newer TTC nail. Both nailing systems are locked proximally and distally and provide a short radius laterally directed distal curve. Mean time to union is 4.3 months [3-10]. Average AOFAS hindfoot score post-operatively is 65, with a mean improvement of 40 points from the pre-operative score in the TTC nail group. Post-operative complications included deep infection, amputation and a non-union rate of 10% overall. In the humeral nail group, four symptomatic stress reactions [8%] and three fractures of the tibia [6%] occurred at the tip of the nail. No stress-riser effect has to date been seen in the TTC nail group. Prominent metalwork removal has also been significantly reduced in the TTC nail group.

Our results show hindfoot fusion using a curved intramedullary nail to be an effective technique in complex cases of hindfoot arthritis and deformity. Anatomically specific alterations to the nail have resulted in a significant reduction in certain complications. Alternate proximal locking options in the TTC nail have reduced prominent metalwork and, more significantly, the incidence of stress reactions and fractures appears to have been eliminated.