Background

NICE guidance suggests that caudal epidural injections of steroid and local anaesthetic may be considered for acute and severe sciatica, however studies have demonstrated limited long-term benefit and impact on future surgery. This study aimed to investigate the use of caudal epidural injections in a district general hospital setting and the rate of subsequent operation.

The use of navigation systems to aid in the performance of total knee replacement has become an accepted method of treatment. Previous studies have shown that by using computer aided navigation the components can be implanted with more reproducible accuracy.

We present the results of a prospective randomised trial, with ethical committee approval that was performed to compare the use of a new, two-pin system with the original three-pin system to fix the tracker to bone. There were 37 patients in the two-pin group and 31 patients in the three-pin group. Pre-operative demographic data was similar. Patients were assessed pre and post operatively clinically using the Knee Society Score, WOMAC and SF36. Radiographic assessment was performed using “The Perth CT Protocol.”

At one year there was no significant difference clinically between either group. Radiographic assessment showed no significant difference in the results of all the prosthesis variables as measured by the Perth CT Protocol, except in the femoral prosthesis absolute varus/ valgus position, with the two-pin group being more accurate. The upgraded tracker fixing system in the computer navigation system allows as accurate implantation as the earlier system with less patient morbidity.

Introduction Maquet views are a well established method of determining the axial alignment of the lower limb in the coronal plane and their use in the assessment of total knee replacement is widespread. It is an awkward investigation for both patient and radiographer and we compared them to the information that can be obtained using the new generation of Helical CT scanners.

Results We prospectively studied a cohort of 60 patents undergoing TKR. As part of their routine post-operative follow-up they had a standard series of AP and Lateral radiographs (performed under fluoroscopic control) in addition to the Maquet views and a CT scan of their lower limbs. All plain films were performed at the same hospital by the same group of radiographers, while all CTs were performed on the same scanner using a predetermined protocol, and post processing performed by the same individual. Maquet views gave a good assessment of coronal alignment but were also shown to have a much high interobserver error than CT. Maquet views took on average three times longer for the radiographers to perform than CT, were often repeated as technically demanding, and patients (especially the elderly and infirm) often found it difficult and uncomfortable to comply with the required positioning. CT views on each patient (which incorporated standard slices and a scanogram) took a few minutes of time in the scanner allowing a quick throughput when patients arrived in clinic. Patients were supine, a position they all found easy to adopt, and radiographers reported that they found them less difficult to perform. The femoral and tibial axes were easily determined, and rotation easily assessed from the femoral epicondyles, negating the projection errors due to malrotation that may compromise the accuracy of Maquet views. Radiation dosage for the CT is higher than a single Maquet view, but these are often repeated due to poor exposure, increasing the dosage above that of CT.

Conclusions We have used a spiral CT protocol with much success and feel that its greater accuracy, coupled with the information gained on sagittal alignment and component rotation means that the older Maquet view has now been superceded. We also feel that the amount of information recorded by a single investigation may prove invaluable in subsequent investigation of pain or suspected loosening, and very helpful in planning any required revision.

Results in revision Hip surgery are compromised where there is extensive bony destruction or significant bone loss. While restoration of bone stock and a return to normal anatomy is the gold standard this is not always possible and may not be required in those patients with lower functional demands and other co-morbidities. The senior authors designed a new hip prosthesis as an aid to revision Arthroplasty and to allow them to bypass defects in the proximal femur. This was a titanium modular cemented prosthesis of varying lengths (from 140mm to 220mm) with a distal flange to transmit compressive loads. It used cement to obtain fixation in the remaining bone, had a short offset designed to reduce torsional loading and a standard (12/14mm) trunion to allow the use of a variety of modular heads.

Operative technique: A transfemoral approach was used allowing easy removal of the old prosthesis, cement and other debris. This also gives an excellent view of the acetabulum if this is also to be revised. The distal femur is sectioned transversely and an appropriately sized component selected, the remaining femur is reamed to 14mm and cemented in place. The proximal femur is then closed over the prosthesis and held with cerclage bands. Full weight bearing was allowed once quadriceps function had been regained.

Results: 48 proximal femoral replacements were performed in 47 patients between December 1992 and June 1997. 12 patients died and 6 declined follow up. The remaining patients were seen in clinic and radiographs of the femur were performed. There was a significant reduction in the postoperative pain score (p< 0.01), and improvement in the Harris hip score. 7 patients suffered dislocations, 4 responding to conservative measures after a single episode. There were 5 implants revised, 3 to total femoral replacements and 1 to a calcar replacing prosthesis. Most patients were satisfied with their result, and all but 1 walk with minimal walking aids. Despite its high complication rate we continue to use this prosthesis as we feel that it remains as a useful alternative in the management of selected low demand patients.