VAS neck pain: Fusion group/arthroplasty group: Preoperatively 6.2/5.9 n.s., 6 weeks 3.5/3.1 n.s., 12 weeks 2.1/1.9 n.s, 1 year 2/2.1 n.s. VAS arm pain: Fusion group/arthroplasty group: Preoperatively 5.5/5.3 n.s., 6 weeks 2.6/2.4 n.s., 12 weeks 1.7/1.8 n.s, 1 year 2/1.9 n.s. Neck disability index: Fusion group/arthroplasty group: Preoperatively 43/40 n.s., 6 weeks 28/23 p<
0.05., 12 weeks 18/14 p<
0.05, 1 year 20/15 p<
0.05. SF-36 subscore pain: Fusion group/arthroplasty group: Preoperatively 36/37 n.s., 6 weeks 42/44 n.s., 12 weeks 52/58 p<
0.05, 1 year 52/60 p<
0.05. SF-36 subscore function: Fusion group/arthroplasty group: Preoperatively 52/54 n.s., 6 weeks 57/59 n.s., 12 weeks 60/62 n.s, 1 year 64/67 n.s. SF-36 subscore vitality: Fusion group/arthroplasty group: Preoperatively 42/44 n.s., 6 weeks 45/46 n.s., 12 weeks 50/52 n.s, 1 year 54/56 n.s. In the fusion group we had 1 recurrent radiculopathy and 1 non union without the need of further intervention. In the arthroplasty group we faced 1 recurrent laryngeus recurrens nerve palsy and 3 spontaneus fusions within 1 year postoperatively, which might not be classified as complication.
Component migration after THR is directly correlated with loosening and reported to be predictive for the long-term survival rate. In literature, four different patterns of stem-migration are reported. Likewise, periprothetic osteolytic zones indicate the risk of loosening and revision in the further course. Nevertheless, little is known about the distinguish migration behaviour between cemented and uncemented stems throughout the process of loosening. The aim of this study was to evaluate the influence of cementing on migration behaviour of loose femoral components after THR. A total of 207 stem-revisions have been performed at our institution between 1996 and 2001. Only patients with aseptic loosening after primary hip replacements were included in the present study. Thus, 75 patients had to be excluded due to other reasons for loosening. Migration analysis was done with the EBRA-FCA method (Einzel-Bild-Röntgen-Analyse, Femoral Component Analysis). In addition, a radiographic analysis was performed following Gruen et al. For migration analysis, a minimum of four x-rays per series are required. Hence, another 72 patients had to be excluded due to insufficient x-ray documentation. A total of 40 cemented (Group A) and 20 uncemented (Group B) femoral components could be analysed. There were no significant differences between the two groups with regard to age (60 years for Group A, 56 years for Group B), gender or side. Mean number of radiographs per series was 7.2 for Group A and 7.9 for Group B respectively. Mean stem survival differed between the two groups (11.3 years for Group A and 8.8 years for Group B), but without statistical significance (T-Test: p>
0.05). Differences in migration behaviour and distinct types of loosening after cemented and uncemented total hip replacement will be presented.
In navigated total hip arthroplasty, the pelvis and the femur are tracked by means of rigid bodies fixed directly to the bones. Exact tracking throughout the procedure requires that the connection between the marker and bone remains stable in terms of translation and rotation. We carried out a cadaver study to compare the intra-operative stability of markers consisting of an anchoring screw with a rotational stabiliser and of pairs of pins and wires of different diameters connected with clamps. These devices were tested at different locations in the femur. Three human cadavers were placed supine on an operating table, with a reference marker positioned in the area of the greater trochanter. K-wires (3.2 mm), Steinman pins (3 and 4 mm), Apex pins (3 and 4 mm), and a standard screw were used as fixation devices. They were positioned medially in the proximal third of the femur, ventrally in the middle third and laterally in the distal portion. In six different positions of the leg, the spatial positions were recorded with a navigation system. Compared with the standard single screw, with the exception of the 3 mm Apex pins, the two-pin systems were associated with less movement of the marker and could be inserted less invasively. With the knee flexed to 90° and the dislocated hip rotated externally until the lower leg was parallel to the table (figure-four position), all the anchoring devices showed substantial deflection of 1.5° to 2.5°. The most secure area for anchoring markers was the lateral aspect of the femur.
Instruments used in surgery which rotate or vibrate at a high frequency can produce potentially contaminated aerosols. Such tools are in use in cemented hip revision arthroplasties. We aimed to measure the extent of the environmental and body contamination caused by an ultrasound device and a high-speed cutter. On a human cadaver we carried out a complete surgical procedure including draping and simulated blood flow contaminated with Environmental contamination was present in an area of 6 x 8 m for both devices. The concentration of contamination was lower for the ultrasound device. Both the ultrasound and the high-speed cutter contaminated all members of the surgical team. The devices tested produced aerosols which covered the whole operating theatre and all personnel present during the procedure. In contaminated and infected patients, infectious agents may be present in these aerosols. We therefore recommend the introduction of effective measures to control infection and thorough disinfection of the operating theatre after such procedures.