The development of spinal deformity in children with underlying neurodisability can affect their ability to function and impact on their quality of life, as well as compromise provision of nursing care. Patients with neuromuscular spinal deformity are among the most challenging due to the number and complexity of medical comorbidities that increase the risk for severe intraoperative or postoperative complications. A multidisciplinary approach is mandatory at every stage to ensure that all nonoperative measures have been applied, and that the treatment goals have been clearly defined and agreed with the family. This will involve input from multiple specialities, including allied healthcare professionals, such as physiotherapists and wheelchair services. Surgery should be considered when there is significant impact on the patients’ quality of life, which is usually due to poor sitting balance, back or costo-pelvic pain, respiratory complications, or problems with self-care and feeding. Meticulous preoperative assessment is required, along with careful consideration of the nature of the deformity and the problems that it is causing. Surgery can achieve good curve correction and results in high levels of satisfaction from the patients and their caregivers. Modern modular posterior instrumentation systems allow an effective deformity correction. However, the risks of surgery remain high, and involvement of the family at all stages of decision-making is required in order to balance the risks and anticipated gains of the procedure, and to select those patients who can mostly benefit from spinal correction.

Introduction: Tibial augments are required to replace bone loss in the proximal tibia during revision total knee replacement and can be either a rectangular ‘block’ shape or an angled ‘wedge’ shape.

Purpose of study: We have identified a high failure rate with the ‘wedge’ shape currently used in the Co-ordinate (DePuy) revision knee system.

Methods: We report a series of revision total knee replacement procedures performed using the Co-ordinate system. All revision ‘angled’ tibial wedge implants were selected from our prospective database containing follow up records for knee replacements. Patients underwent clinical and radiological review at three months following the procedure, on the anniversary of surgery and then on a yearly basis. Those with fewer than 12 months follow-up were excluded.

Results: Between December 1993 and February 2006, a total of 34 patients (19 female, 15 male) required revision knee arthroplasty with an ‘angled’ wedged tibial augment. Mean age at surgery was 59.3 years (range 46–93). Five cases were excluded due to absence of follow-up (four requiring further surgery for infection and one due to unrelated medical complications). Of the remaining 29 cases, 16 (55.2%) had no problems with the tibial implant, while 13 (44.8%) exhibited radiological changes on review. Tibial implant migration was seen in 5 cases (17.2%), all within three years of surgery. One of these has needed further revision surgery and the other four are expected to need revision in the future. Seven (24.1%) were found to have a tibial radiolucent zone, which was progressive in four cases. There was one case of stem dissociation.

Conclusion: ‘Angled’ tibial wedge implants are associated with a high rate of implant migration and loosening, presumably due to the effect of shear forces. Use of these implants should be reserved for low demand patients.

Introduction: An important factor affecting the stability of circular fine wire frames is the wire crossing angle, where an angle of 90 degrees confers optimal stability. Safe anatomical ‘corridors’ have been described to avoid neurovascular structures, but often limit the crossing angle. In the distal tibia the posterior tibial artery and tibial nerve wind medially facilitating safe placement of a posterior to anterior ‘retrofibular’ wire. The present study aims to identify structures at risk during ‘retrofibular’ wire placement and determine the level at which this can be used safely.

Methods: A dissection based study of 10 embalmed lower limbs. Wires of 1.8mm diameter were inserted at increments along the tibia. These were placed against the posterior surface of the fibula and ‘stepped’ medially past the posteromedial border onto the tibia. Wires were introduced from posterior to anterior, between 30 degrees and 45 degrees to the sagittal plane. This angle is estimated, reproducing clinical practice. Standard dissection techniques were used to identify the path of wires and distance from neurovascular structures.

Results: In the distal quarter of the tibia wires avoided the posterior tibial neurovascular bundle (mean distance 21.7mm) although passed close to the peroneal artery (mean distance 1.2 mm). Of the 30 wires placed in the distal tibia, 29 (97%) passed through the leg without damage to any neurovascular structures. Anterior tendons were tethered by 13% of wires placed in the distal quarter of the tibia.

Discussion: Retrofibular wire placement facilitates an optimal crossing angle, although is not described in standard atlases. Use in the lower quarter of the tibia does not threaten the posterior tibial neurovascular bundle. However, peroneal artery injury is a possibility. The clinical significance of peroneal artery injury at this level is unclear but should be considered when using this technique.