Introduction

Total femur implantation is a rare and challenging procedure in final revision surgery of hip and knee arthroplasties. Reports of this operation technique are even rare in literature. In this study we retrospectively analyse our patients with total femur implants.

Introduction: The removal of well-fixed cementless acetabular components can be challenging and may lead to tremendous bone loss. The options for a well-fixed, mal-positioned cup include cup revision, face-changing liners, or eccentrically cementing a liner in a more appropriate position. This study reviews our experience with a technique of eccentrically cemented acetabular liners in wellfixed, malpositioned cementless acetabular components.

Methods: From 2002 to 2004, 30 patients underwent acetabular revisions with eccentrically cemented liners into well-fixed, malpositioned acetabular components. The range of malpositioning included excessive abduction, extreme anteversion, retroversion, and neutral cup position. The cemented liners were downsized by 2–4 mm to provide an acceptable cement mantle and were positioned more appropriately in terms of both abduction angle and anteversion.

Results: Mean follow-up was 4 years (3–5). Liners were reoriented for the following reasons 7 excessive abduction, 8 extreme anteversion, 10 neutral and retroversion, and 5 combined inappropriate version and abduction. One liner loosened at 18 months and required cup revision. The other 29 functioned well with no dislocations. Radiographic analysis demonstrated no loosening in 29 cups at a mean of 4 years (3–5).

Conclusion: Eccentrically cemented liners into well fixed, malpositioned acetabular components in a reasonable option that has promising short-term results.

Introduction: Clinical follow-up studies are sample based, in contrast to arthroplasty register data, which refer to the entire population treated. Aim of this study is to assess the differences in revision rate to quantify bias-factors in published literature.

Materials and Methods: A structured literature review of Medline-listed peer reviewed journals on examples has been performed concerning implants with sufficient material in both data sources available. Products with inferior outcome were subsumed in a subgroup.

Results: The number of cases presented in peer reviewed journals are relatively low in general and show a high variability.

The average revision rate in peer reviewed literature is significantly lower than in arthroplasty register data-sets.

Studies published by the inventor of an implant tend to show superior outcome compared to independent publications and Arthroplasty Register data. Factors of 4 to more than 10 have been found, which has a significant impact for the results of Metaanalyses.

When an implant is taken from the market or replaced by a successor there is a significant decrease in publications, which limits the detection of failure mechanisms such as PE wear or insufficient locking mechanisms.

The final statement made about the product under investigation seem to follow a certain mainstream.

Discussion and Conclusion: Arthroplasty Register datasets are superior to Metaanalyses of peer reviewed literature concerning revision rate and the detection of failure mechanisms. Combined reviews could reduce bias factors and thereby raise the quality of reports.

Background: Adjuvant radiotherapy has shown to improve local control in patients with soft tissue sarcoma. Additional brachytherapy represents a means of enhancing the therapeutic ratio, as biological and dosimetric advantage over single external-beam irradiation (EBRT) can be expected. High-dose-rate intraoperative brachytherapy (IOHDR) as a boost therapy should be able to further diminish the rate of local recurrence even when performing marginal resection.

Patients and Methods: Within a period of 10 years, we prospectively studied 84 adult patients treated by marginal resection, IOHDR using the flab technique and EBRT for soft tissue sarcomas. There were 67 high-grade and 17 low-grade tumors, 70 were > 5 cm. Mean follow-up was 37.2 months (range 1–121 months).

Results: There were two local recurrences, following further resection one patient is without evidence of tumor. No treatment-related loss of limb or life occurred. All patients maintained functioning extremities as evidenced by a mean Musculoskeletal Tumor Society (MSTS) functional score of 89.1 (43–100). Treatment-related wound morbidity occurred in a fifth of all patients, as consequence of revision surgery one patient sustained neurovascular complications. The 5-year actuarial disease-free survival was 81.6%. Meta-static disease developed in eighteen patients, all of them had died at last follow-up. There were four cases of late radiation related complications (two fractures of the femur due to radiation osteonecrosis and two late palsies of ischial nerve).

Conclusions: IOHDR using the flab technique in combination with EBRT and marginal resection is an efficient treatment technique leading to excellent local control rates and limited functional impairment.

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.

Successful total knee arthroplasty (TKA) is dependent on the correct alignment of implanted prostheses. Major clinical problems can be related to poor femoral component positioning, including sagittal plane and rotational malalignment. A prospective randomized study was designed to test whether an optical navigation system for TKA achieved greater implantation precision than a non navigated technique. The primary variable was rotation of the femoral component in the transverse plane measured from post operative radiographs and CT images. Sixty-four patients were included in the study. All patients received the Duracon total knee prosthesis. The patients were randomly divided into two groups; Group C patients underwent conventional TKR without navigation, Group N patients underwent TKR using a computer assisted Knee Navigation System. Analysis revealed that patients in Group N had significantly better rotational alignment and flexion angle of the femoral component than patients in Group C. In addition, superior post operative alignment of the mechanical axis, posterior tibial slope, and rotational alignment was achieved for patients in Group N. The use of a navigation system provides improved alignment accuracy. Specifically, it can help to avoid femoral malrotation and errors in axial alignment.

Studies on the migration of an implant may be the only way of monitoring the early performance of metal-on-metal prostheses. The Ein Bild Roentgen Analyse - femoral component analysis (EBRA-FCA) method was adapted to measure migration of the femoral component in a metal-on-metal surface arthroplasty of the hip using standard antero-posterior radiographs. In order to determine the accuracy and precision of this method a prosthesis was implanted into cadaver bones. Eleven series of radiographs were used to perform a zero-migration study. After adjustment of the femoral component to simulate migration of 3 mm the radiographs were repeated. All were measured independently by three different observers.

The accuracy of the method was found to be ± 1.6 mm for the x-direction and ± 2 mm for the y-direction (95% percentile). The method was validated using 28 hips with a minimum follow-up of 3.5 years after arthroplasty. Seventeen were sound, but 11 had failed because of loosening of the femoral component. The normal (control) group had a different pattern of migration compared with that of the loose group. At 29.2 months, the control group showed a mean migration of 1.62 mm and 1.05 mm compared with 4.39 mm and 4.05 mm in the failed group, for the centre of the head and the tip of the stem, respectively (p = 0.001). In the failed group, the mean time to migration greater than 2 mm was earlier than the onset of clinical symptoms or radiological evidence of failure, 19.1 versus 32.2 months (p = 0.001) and 24.8 months (p = 0.012), respectively.

EBRA-FCA is a reliable and valid tool for measuring migration of the femoral component after surface arthroplasty and can be used to predict early failure of the implant. It may be of value in determining the long-term performance of surface arthroplasty.

Aims: Postoperative dislocation of the implant is still an unsolved problem in THR. Malposition of the socket is reported to be one major risk factor. The aim of this study was to investigate the inßuence of cup orientation on the probability of postoperative prosthetic dislocation. Methods: The orientation of the socket was studied in 137 patients with postoperative dislocations, and compared with a control group (n=342). The EBRA-method (Ein-Bild- Roentgen-Analyse) was used to determine anteversion and inclination angles of the cups. A previous study showed that the precision of the method for measuring these parameters was ± 1degree (SD 0.33). Results: Mean values for the orientation of the prosthetic cup in the control group was 44¡ for inclination and 15¡ for anteversion. Patients with anterior dislocations after primary hip replacements showed signiþcant differences of the mean inclination (48¡, Mann-Whitney-Test: p=0.045) and anteversion angle (17¡, p=0.015). For posterior dislocations, mean inclination was 42¡ (p=0.277) and anteversion 11¡ (p=0.002) respectively. After revision hip arthroplasty, only patients with posterior dislocation of the implant showed signiþcant differences of the cup orientation (inclination: 40¡, p=0.03; anteversion:12¡,p=0.017). Conclusions: The results demonstrate the importance of accurate positioning of the socket to minimise the risk of subsequent dislocation. An anteversion of 15¡ and an inclination of 44–45¡ has the lowest at risk for dislocation.