The in vivo evaluation of patellofemoral contact pressures in a posterior stabilized compared to posterior cruciate sacrificing total knee arthroplasty (TKA). A prospective descriptive non randomized study was performed on 8 patients. A standard approach to a TKA was performed using a balanced gap technique, while the patella was prepared for a resurfacing. The trial components for the posterior stabilized (PS) TKA where inserted including the gas sterilized pressure transducer (a patella button). Soft tissue was approximated and the knee was taken through full range of movement. Patellofemoral pressure was measured and captured continuously through the full range of movement. The posterior cruciate sacrificing (CS) components were inserted into the same patient and the procedure repeated. In addition, anterior translation of the tibia relative to the femur was measured at 90 degrees. The transducer was removed and final components, including a patella resurfacing were inserted.Purpose Of Study
Methods
The aim is to assess the use of non-fusion instrumentation “growth rods” in early onset scoliosis (EOS). A retrospective review of 12 consecutive patients who had undergone a growth rod procedure for EOS was performed. Six patients had neuromuscular scoliosis, 5 had juvenile idiopathic scoliosis while one had a congenital aetiology. Growth constructs were predominately constructed from modular commercially available sets using hooks, screws and connection blocks. One VEPTR was used in a severe kyphoscoliosis. Patients returned to theatre at 6 monthly intervals for a lengthening procedure. Patients were assessed with regards to age at presentation, age at surgery, indications for surgery, initial Cobb angle, post- operative Cobb angle, number of lengthening's done, instrumentation used, amount of spine growth achieved and complications.Purpose of study
Methods
Neck pain can be caused by pressure on the spinal cord or nerve roots from bone or disc impingement. This can be treated by surgically decompressing the cervical spine, which involves excising the bone or disc that is impinging on the nerves or widening the spinal canal or neural foramen. Conventional practise is to fuse the adjacent intervertebral joint after surgery to prevent intervertebral motion and subsequent recompression of the spinal cord or nerve root. However fusion procedures cause physiological stress transfer to adjacent segments which may cause Adjacent Segment Degeneration (ASD), a rapid degeneration of the adjacent discs due to increased stress. ASD is more likely to occur in fusions of two or more levels than single level fusions and is more common where there is existing degeneration of the adjacent discs, which is not unusual in people over 30 years of age. Partial dynamic stabilisation, which generally involves a semi-rigid spinal fixation, allows a controlled amount of intervertebral motion (less than physiological, but more than fusion) to prevent increased stress on the adjacent segments (potentially preventing ASD) whilst still preventing neural recompression. Partial dynamic stabilisation is suitable for treating spinal instability after decompression as well as certain degenerative instabilities and chronic pain syndromes. Dynamic stabilisation and semi-rigid fixation systems for the spine are typically fixated posteriorly. However, choice of posterior surgical stabilisation techniques in the cervical spine is limited due to the size of the osseous material available for fixation and the close proximity of the neural structures and the vertebral artery. Posterior dynamic stabilisation systems for stabilisation of the lumbar spine often use the pedicle as an anchor point. Using the pedicle of the cervical spine as an anchor point is technically difficult because of its small size, angulation and proximity to neurovascular structures. Therefore, one of the main challenges to provide stabilisation in the cervical spine is the limitations of the anatomy. This presentation will introduce a novel spinal implant (patent pending) which is proposed for the cervical spine to provide partial dynamic stabilisation in the C3 to T1 region from a posterior approach. The implant is a single unit with a safe and technically simple insertion technique into the lateral masses. The implant uses a simple mechanism to allow limited intervertebral motion at each instrumented level. It is hoped that the simplicity of the device and removing the need to provide a bone graft anteriorly may reduce the cost of the procedure compared to traditional fusion and competing surgeries.
