Die Aufklärung des Patienten muss immer durch einen Arzt erfolgen. Jeder ärztliche Heileingriff erfüllt nach der aktuellen Rechtsprechung den Tatbestand der Körperverletzung. Eine Einwilligung zu einem operativen Eingriff ist juristisch nur wirksam, wenn der Patient zuvor die Argumente für und wider abwägen kann. Daher muss die Aufklärung nicht nur so umfassend sein, dass der Patient den Eingriff, die Alternativen und die Konsequenzen selbst erfassen kann, sondern auch zeitlich so gelegt sein, dass dem zu Behandelnden bis zum Beginn der Maßnahme noch eine ausreichende Überlegungsfrist bleibt. Nicht nur der Eingriff selbst, sondern auch die postoperativen Verhaltensmaßregeln und empfohlenen Kontrolluntersuchungen müssen aufgeklärt und dokumentiert werden. Bei der Aufklärung sind die Wahrung des Selbstbestimmungsrechtes, der Autonomie und der Entscheidungsfreiheit des Patienten zu berücksichtigen und haben Vorrang vor der medizinischen Auffassung des Arztes.

Failed total knee replacement with compromised bone and soft-tissues can be challenging. In these situations, arthrodesis remains a treatment option of a limb-saving procedure.

Background: Short stem prostheses have been developed to preserve the femoral bone stock. The purpose of this study was to evaluate the stress-shielding effect in the proximal femur as well as the micromotion between bone and implant as a measure of primary stability for a new short stem in comparison to a clinically successful short stem and a straight stem.Methods: Using paired fresh human femurs, stress shielding was examined by using tri-axial strain gage rosettes. The strain distribution of the proximal femur was measured before and after implantation of three cementless prostheses of different design concepts and stem lengths. Furthermore, interface motion and rotational stability were investigated under dynamic loading (100-1600 N) after 100,000 load cycles using inductive miniature displacement transducers.Findings: A reduction of longitudinal cortical strains in the proximal femur was displayed for all three implants. The reduction was less pronounced for the shorter stem implants, however.Interface motion was below the critical threshold of 150 mu m at almost all measuring points for all three stems, with a tendency for greater rotational stability in the shorter stem implants.Interpretation: The new short stem prosthesis displayed reduced stress shielding and comparable primary stability to an established short stem and a conventional shaft design. Shortening the stem did not negatively influence primary stability. The clinical implications of these findings remain to be proven. (C) 2011 Elsevier Ltd. All rights reserved.

This prospective 12 months dual energy x-ray absorptiometry study evaluated differences in periprosthetic bone mineral density (BMD) in 25 patients undergoing cementless and in 18 patients undergoing cemented unilateral total hip arthroplasty (THA) using the Optan stem, which has the same geometric design for both fixation options. The clinical outcome scores after one year were excellent in both groups. Periprosthetic BMD measurement demonstrated bone loss medially and laterally in the proximal femoral regions following cementless fixation, whereas cemented fixation resulted in predominantly lateral bone resorption. The fixation technique appeared to have a major influence on the femoral BMD changes after THA.

Postoperative alignment is a predictor for long-term survival of total knee arthroplasty (TKA). The purpose of this study was to evaluate whether or not preoperative deformities predispose to intraoperative malposition of TKA components. A retrospective radiographic analysis of 53 primary TKA cases was performed. Preoperative AP hip to ankle and lateral knee radiographs were compared with postoperative views to evaluate component positioning. The following angles were measured: the hip–knee–ankle (HKA) angle expressing the mechanical axis of the leg, the mechanical lateral distal femur angle (mLDFA), the medial proximal tibia angle (MPTA), the posterior distal femur angle (PDFA), and the posterior proximal tibia angle (PPTA). Postoperative measurement of the HKA revealed 34.0% of the cases had a deviation of >±3° from neutral alignment. Sixteen knees (30.2%) were in varus and, with one exception, all presented with severe varus gonarthrosis prior to surgery with a mean tibiofemoral angle of 12.4° compared with 1.0° of valgus in the optimally aligned group. Patients (93.3%) with preoperative valgus malalignment showed optimal postoperative HKA. Odds ratios for malalignment of TKA for varus knees in comparison with valgus knees were 7.1 for HKA, 2.4 for MPTA, 4.9 for PDFA, and 1.7 for PPTA. The overall number of outliers in the presented data corresponds well with reports from other authors using different implants and guide systems. The presented data indicate that patients with preoperative varus alignment have a higher risk of postoperative implant malposition than patients with valgus alignment. The data supports that preoperative varus deformity predisposes to varus malposition of TKA. The risk for intraoperative malposition is significantly lower in valgus knees.

BACKGROUND:Stress shielding of the proximal femur has been observed in a number of conventional cementless implants used in total hip arthroplasty. Short femoral-neck implants are claiming less interference with the biomechanics of the proximal femur. The goal of this study was to investigate the changes of bone-mineral density in the proximal femur and the clinical outcome after implantation of a short femoral-neck prosthesis.METHODS:We prospectively assessed the clinical outcome and the changes of bone mineral density of the proximal femur up to one year after implantation of a short femoral neck prosthesis in 20 patients with a mean age of 47 years (range 17 to 65). Clinical outcome was assessed using the Harris Hip Score. The WOMAC was used as a patient-relevant outcome-measure. The bone mineral density was determined using dual energy x-ray absorptiometry, performed 10 days, three months and 12 months after surgery.RESULTS:The Harris Hip Score improved from an average preoperative score of 46 to a postoperative score at 12 months of 89 points, the global WOMAC index from 5,3 preoperatively to 0,8 at 12 months postoperatively. In contrast to conventional implants, the DEXA-scans overall revealed a slight increase of bone mineral density in the proximal femur in the 12 months following the implantation.CONCLUSION:The short femoral neck stem lead to a distinct bone reaction. This was significantly different when compared to the changes in bone mineral density reported after implantation of conventional implants.

Aim To measure the inter- and intraobserver reliability of two radiologic classification systems in the evaluation of severity of osteoarthritis secondary to developmental dysplasia of the hip in adult patients and to compare these systems to historically published data on two more commonly used classification systems described by Crowe and by Hartofikakidis. Material and methods Eighty-six dysplastic hips on 66 anteroposterior standard pelvic x-rays were rated according to the criteria of Eftekhar and Kerboul by three observers with different levels of clinical training. To assess intraobserver reliability, the measurement was repeated 3 months later. Statistical analysis was performed by calculating the weighted kappa correlation coefficient and the overall kappa coefficient. Results Both classification systems showed a sufficient interobsever reliability, reaching a kappa coefficient of 0.73 for the system according to Eftekhar and 0.716 for the Kerboul classification system. Intraobserver reliability revealed a kappa coefficient of 0.778 for the Eftekhar system and 0.697 for the classification according to Kerboul. Conclusion Both systems showed good inter- and intraobserver reliability for use in daily practice. However, they did not reach the known reliability of the grading systems published by Crowe and by Hartofikakidis. Because these systems are more frequently used, we would recommend one of them to grade the severity of osteoarthritis secondary to developmental dysplasia of the hip in adult patients instead of the ones described by Eftekhar or by Kerboul.

A number of studies have reported a significant improvement of the postoperative alignment, when computer-navigated total knee arthroplasty (TKA) was compared with conventional techniques. However, no studies are available on the functional and patient-relevant outcomes after computer-assisted knee replacement. In a prospective, randomized trial comparing 27 computer-assisted TKAs with 25 conventional implantations, the Knee Society Score was used to assess functional status, and the WOMAC questionnaire was used to record the disease-specific, patient-relevant outcome. At a twelve-month follow-up no significant difference was detected between the two patient groups in either the scores or the number of complications and range of postoperative knee flexion. The results are in agreement with those reported in other studies on the effect of conventional TKA. With the patient group of this size it can be concluded that computer-navigated TKA gives short-term resuits comparable with those achieved by conventional methods of implantation.

Aim: The aim of this study is to report the survival and mid-term results including patient-relevant outcome measures with a small-sized cemented stem (CDH-stem) for the treatment of coxarthrosis secondary to developmental dysplasia of the hip. Method: 33 total hip replacements were performed with the CDH stem, 29 of which (88%) were included in the follow-up after an average of 7.6 years. According to the classification system of Hartofilakidis et al., 10 hips were classified as type 1, 15 as type 2, and 3 as type 3. Survival was predicted using Kaplan-Meier survivorship analysis with revision as the end point. Results were assessed using the Harris hip score, as well as the WOMAC and SF-36 as patient-relevant outcome measures. Results: Survival at thirteen years was predicted to be 92.4% for the stem and 87.6% for the varying acetabular implants used. At the time of the final follow-up, the average Harris hip score was 82.45 points. The global WOMAC index averaged 2.1, the average SF-36 score was 66.2 points. Conclusions: The data support the use of a small-sized cemented stem in small femora for total replacement of the dysplastic hip. To the best of our knowledge, this is the first study utilising the well validated WOMAC and SF-36 as patient-relevant outcome measures in this subgroup of patients.

Background A number of clinically used total hip femoral implants are claiming a more or less physiologic load transfer, mostly without providing experimental data. To compare three clinically cementless total hip stems of fundamentally different design, the strain distribution before and after insertion in human cadaver femora was measured in vitro.Methods. A conventional straight stem based on a distal anchorage concept, a so-called "anatomic" stem designed to have a proximal force transmission and a "stemless" femoral neck prosthesis were evaluated under similar loading conditions. Strain distribution was measured with tri-axial strain-gauge rosettes before and after implantation of the stems. The same bending moment was used in all femora tested to compare magnitude and direction of the resulting strains.Findings. The straight and the "anatomic" stem both led to a decrease of the longitudinal strains in the proximal femur, while the femoral neck implant mainly led to an increase of measured strains on the lateral side of the greater trochanter. The observed medial strains were closer to physiological values in the "stemless" prosthesis than those of the two full-stem prosthesis.Interpretation. The decrease in strains seen in the proximal region of the femora with implanted conventional hip prosthesis corresponds well to the decrease of bone density in this region noted in clinical follow-up studies. The more physiological strain at the inferior base of the neck seen in "stemless implant" may induce a remodelling process that better retains bone stock in that area. However, the increase of strains noted after implantation of this prosthesis require further investigation to assess the risk they may pose to bone failure. (c) 2006 Elsevier Ltd. All rights reserved.

Objective: To assess the inter-observer and intra-observer reliability of two commonly used radiographic classification systems in the evaluation of hip dysplasia in skeletally mature adults. Design: Three observers with different levels of training independently classified 62 dysplastic hips on 51 standard anteriorposterior pelvis radiographs according to the criteria defined by Crowe and by Hartofilakidis. To assess intra-observer reliability, the same radiographs were reviewed 3 months later by the same observers. Patients: At the time of the radiographic examination, the mean age of the 51 patients had been 54 years (range 18-82 years). Results: A high correlation concerning the inter- and intra-observer reliability of both systems was demonstrated. Inter-observer reliability displayed a weighted kappa coefficient of 0.82 for the Crowe and 0.75 for the Hartofilakidis classification. Intra-observer reliability showed a kappa coefficient of 0.86 and 0.79, respectively. Conclusions: Both classification systems can be recommended to compare collectives of adult patients with congenital dysplasia of the hip. However, for future clinical practice, it would be advisable to agree on one universally accepted system as a standard in the literature.

AIM:The aim of this study is to report the survival and mid-term results including patient-relevant outcome measures with a small-sized cemented stem (CDH-stem) for the treatment of coxarthrosis secondary to developmental dysplasia of the hip.METHOD:33 total hip replacements were performed with the CDH stem, 29 of which (88 %) were included in the follow-up after an average of 7.6 years. According to the classification system of Hartofilakidis et al., 10 hips were classified as type 1, 15 as type 2, and 3 as type 3. Survival was predicted using Kaplan-Meier survivorship analysis with revision as the end point. Results were assessed using the Harris hip score, as well as the WOMAC and SF-36 as patient-relevant outcome measures.RESULTS:Survival at thirteen years was predicted to be 92.4 % for the stem and 87.6 % for the varying acetabular implants used. At the time of the final follow-up, the average Harris hip score was 82.45 points. The global WOMAC index averaged 2.1, the average SF-36 score was 66.2 points.CONCLUSIONS:The data support the use of a small-sized cemented stem in small femora for total replacement of the dysplastic hip. To the best of our knowledge, this is the first study utilising the well validated WOMAC and SF-36 as patient-relevant outcome measures in this subgroup of patients.

The aim of this study was to determine the accuracy of the software system "Düsseldorf Migration Analysis - Femoral Component Analysis" (DMA-FCA) in measuring stem migration in total hip arthroplasty (THA) on digitised anteroposterior radiographs of the pelvis. Bony and implant landmarks on two consecutive radiographs were used for measurements of subsidence and varus-valgus tilt. The accuracy of the method was determined by reference to radiostereometric measurements (RSA). Using specific comparability limits, comparability analysis of radiographs with respect to femoral positioning is possible with DMA. DMA-FCA and RSA measurements were performed after cementless THR in a population of 60 patients aged 38 to 69 years. With a Cronbach's alpha-index of 0.89 and 0.99 for subsidence and 0.90 and 0.98 for classic varus-valgus-tilt, the intraobserver and interobserver reliability for the DMA-FCA-method was calculated as good. Using RSA as reference method, the accuracy of DMA-FCA was calculated to be 2.51 mm for subsidence and 2.49 degrees for varus-valgus-tilt (95% confidence interval). Without comparison to RSA, DMA measured 1.94 mm for subsidence and 2.35 degrees for varus-valgus-tilt. Based on a comparison with RSA, our results show lower accuracy for DMA-FCA than for EBRA-FCA, but DMA-FCA is easier to use in everyday clinical practice. It is hoped that the use of digital measuring methods such as DMA will become standard for long-term observation and will be integrated into clinical routine in the context of quality assurance of THR.

To compare the alignment after computer-navigated total knee arthroplasty, 52 patients were randomly allocated to 2 groups. Twenty-seven patients received a total knee arthroplasty with the aid of a kinematic computer-navigation system, and 25 patients received a total knee arthroplasty with the conventional method. Both groups were well balanced concerning demographic data and preoperative scores. At 3-month follow-up, the mechanical alignment of the leg reached the desired straight axis in more cases with the computer-navigated implantation. This difference was statistically significant. The femoral and tibial mechanical anteroposterior axis and the femoral and tibial sagittal tilt (slope) measured on sagittal x-rays were not significantly improved in this patient group.