The Clinical Outcome of Custom-Made Implants in Primary and Revision Hip Arthroplasty.

PURPOSE OF THE STUDY Facing the increasing number of priary and revision hip arthroplasties, the therapy of complex osseus defects becomes a crucial issue. Large acetabular defects cannot be treated with standard implant. Individual, customized implants based on 3D computed tomography (CT) scans are used for reconstruction. However, high complication and revision rates come along with final favorable outcomes. MATERIAL AND METHODS Eight patients underwent primary or revision total hip arthroplasty by an anterolateral surgical approach using patient matched implants based on 3D CT scans. Six patients with a Paprosky type IIIB acetabular defect, one patient with a nonunion acetabular and femoral neck fracture and one patient with a severe hip dysplasia were included. The clinical data and the Merle d'Aubigné score assessing the clinical outcome pre- and postoperatively were analyzed retrospectively. RESULTS Patient matched implants were used for eight patients (four male and four female). The mean Merle d'Aubigné score improved from 8.1 (range 2-11) pre-operatively to 13 (range 9-17) at the final follow-up (p < 0.01). Postoperative complications were recorded in 3 cases. CONCLUSIONS Customized implants of severe acetabular defects provide a solution with a favorable outcome. Nevertheless, dislocation presents a significant complication. A reduction of complications in order to achieve the optimal custome-made implant is desirable. Key words: revision arthroplasty, patient-matched implants, Paprosky IIIB defects, clinical outcome.

Development rationale for an articular surface replacement: a science-based evolution.

Hip resurfacing has an enduring appeal because of the advantages of bone conservation and maximal joint stability. However, a far from satisfactory experience with earlier resurfacing designs led to its virtual disappearance in the 1980s. The concept was reintroduced in the late 1990s. The current generation of resurfacing devices generally consisted of a large-diameter metal-on-metal articulation, the femoral components being cemented and the acetabular components utilizing various forms of cementless fixation. The encouraging medium-term results, with a follow-up of up to 8 years using the current generation of surface replacement joints, combined with favourable reports related to long-term performance of some metal bearings have led to a rapid increase in the use of such components with these devices. This trend is most marked in younger, more active patients who have expectations of restoration of lifestyle in addition to improved mobility and pain relief and in whom failure with conventional total hip replacement is much higher than previously reported with more sedentary patients. The aim of this paper is, firstly, to highlight a number of areas of improvement and, secondly, to explain how these may be addressed by making modifications to the design of both implants and instrumentation and to the surgical technique. The areas identified for improvement were tissue preservation (thinner components, and reduced steps between sizes), acetabular cup issues (fixation, insertion, and positioning), femoral component issues (design, loading, and cementation), improved bearing surface characteristics, and simplified precise instrumentation with a low-trauma surgical technique.

Lessons learned from early clinical experience and results of 300 ASR hip resurfacing implantations.

Between August 2003 and April 2005, 300 ASR metal-on-metal resurfacing hip endoprostheses were implanted by the first author and a fellow surgeon. The mean age at surgery was 56.8 years (18-75.9 years) and mean body mass index was 27.6 kg/m2 (range, 19-41 kg/m2). The mean follow-up time was 202 days. The mean Harris hip score improved from 44 pre-operatively to 89 at 3 months post-operatively. In total, eight (2.7 per cent) cases [five neck fractures (1.66 per cent) and three cup revisions (1 per cent)] were revised. Two neck fractures occurred within a group of seven cases of femoral neck notching detected postoperatively; one neck fracture occurred out of two cases of incomplete seating of the femoral implant. A significantly higher (p < 0.001) failure rate was observed for patients who had undergone a previous osteosynthesis of the proximal femur (three revisions in a group of 15 patients). Revision cases had a significantly greater body mass index (p = 0.031). A learning curve was evident from the reduction in revisions from 5 in the first 100 surgical procedures to 2 in the next 100 and 1 in the last 100. These results show the importance of accurate surgical technique and careful patient selection for fourth-generation hip resurfacing implants,

[In vitro investigation of posterior cruciate ligament strain following total knee arthroplasty]. / In-vitro-Untersuchung der Spannung des hinteren Kreuzbandes nach primärer Knieendoprothetik.

AIM: The aim of this biomechanical in vitro study was to assess posterior cruciate ligament (PCL) strain following two different total knee arthroplasty (TKA) designs (fixed versus mobile) with regard to modification of the tibial slope. MATERIAL AND METHODS: We investigated eight Natural Knee I (NK I) prosthesis with fixed bearing and eight Low Contact Stress (LCS) prosthesis with mobile meniscal bearings. TKA was performed using fresh frozen human cadaveric knee joints. PCL strain was measured with implantable force transducers. Knee kinematic assessment was made with a load of 300 Newton and without load using a six-degrees-of-freedom testing device. Modification of the tibial slope was analysed radiographically. Statistical analysis was performed using Student's t test, Wilcoxon rank sum test, and the Spearman coefficient of correlation. RESULTS: Assessment of the tibial slope showed a non-significant increase of 2.1 degrees (p = 0.14) following TKA using the NK I, and of 1.1 degrees (p = 0.12) using the LCS, respectively. Analysis of PCL strain following implantation of the NK I prosthesis revealed non-significant alterations both with (p = 0.74) and without load (p = 0.20). Concerning the LCS prosthesis, a significant decrease in PCL strain was seen with load (p = 0.01), whereas non-significant modifications were measured without load (p = 1.0). The modified tibial slope and modified PCL strain following LCS TKA showed no (with load: r (s) = 0.01) and modest correlation (without load: r (s) = - 0.43), respectively, whereas it was substantial following NK I TKA (with load: r (s) = 0.64, without load: r (s) = 0.70). CONCLUSION: As the NK I prosthesis allows PCL tension to be close to normal as the knee flexes, it can be stated that regular PCL tension after TKA is restorable and, moreover, it can be hypothesised that the effected tension of the PCL mainly depends on the interaction between design of the implant (fixed/mobile) and the functional role of the PCL.

[Clinical outcome following robotic assisted versus conventional total hip arthroplasty: a controlled and prospective study of seventy-one patients]. / Klinisches Outcome nach Roboter-assistierter versus konventionell implantierter Hüftendoprothetik: Prospektive, kontrollierte Untersuchung von 71 Patienten.

AIM: Robotic assisted total hip arthroplasty remains controversial, since wider exposure of the proximal femur and placement of the leg in maximal hip adduction and external rotation using a rigid leg-holder apparatus may impair significantly the hip abductors. Consequently, it is the purpose of this study to analyse and report both clinical outcome and hip abductor function following robotic assisted versus conventional total hip arthroplasty. MATERIAL AND METHODS: 36 robotic-assisted (CASPAR, Orto-Maquet, Rastatt, Germany) and 35 conventional cementless total hip arthroplasties were followed on average for 18 months regarding incidence of complications, Harris hip score, the scoring system according to Merle d'Aubigné and Postel, hip abductor function (using a spring-balance), and incidence of Trendelenburg's sign (according to the Kuhfuss-classification). Statistical analysis was performed in case of continuous data using the t test and the Mann-Whitney test, respectively, and in case of categorical data using Fisher's exact test and the chi-squared test, respectively. The level of significance was set as p < 0.05. RESULTS: Average duration of surgery (CASPAR: 100.6 min; conventional: 51.5 min; p < 0.0001) as well as average loss of haemoglobin (CASPAR: 4.5 mg/dL; conventional: 3.3 mg/dL; p = 0.0002) differed significantly, whereas the incidence of complications (CASPAR: two dislocations, one sciatic paresis, one deep infection; conventional: one dislocation, two fissures), revision rate (CASPAR: 5.6 %; conventional: 2.9 %), and incidence of heterotopic ossifications (CASPAR: 30.6 %; conventional: 17.1 %) was comparable following both procedures (p > 0.05). Improvement of the Harris hip score also was comparable in both groups (CASPAR: 40.9 to 86.1 points; conventional: 39.5 to 88.0 points; p = 0.21), whereas improvement of the score according to Merle d'Aubigné and Postel was significantly greater following the manual procedure (CASPAR: 10.1 to 16.0 points; conventional: 8.3 to 16.6 points; p < 0.0001). Differences between the two groups were also significant regarding hip abductor function (CASPAR: 76.1 %; conventional: 93.8 % of the contralateral hip; p < 0.0001) and incidence of Trendelenburg's sign (CASPAR: 61.1 %; conventional: 25.7 %; p = 0.0014). CONCLUSION: The significant functional impairment following robotic assisted THA should be taken critically into consideration prior to initiating such procedure.

Two-stage exchange of infected knee arthroplasty with an prosthesis-like interim cement spacer.

Two-stage revision in infected knee arthroplasty is standard practice. One problem during the interim period is soft tissue fibrosis. Attempts have been made to preserve leg length and ligament length by introducing spacers, usually made out of antibiotic-loaded bone cement. We present a new interim prosthesis, which is made intra-operatively out of polymethylmethacrylate (PMMA). Antibiotic-loaded cement provides a therapeutic level of antibiotics in the periarticular soft tissue. We report the results in ten patients, who were treated with this prosthesis-like spacer and were prospectively studied. After an average follow-up of 13.5 months, there was no recurrent infection.

High tech the old-fashioned way. An interview with Tom Siebel of Siebel Systems. Interview by Bronwyn Fryer.

There is a growing awareness among corporations that the quality of the customer experience they provide directly affects their bottom line. Many are turning to high-flying software maker Siebel Systems for help in managing those relationships. The young company holds a leadership position in an explosive market-enterprise application software. But customer satisfaction, not dot-com chic, is foremost on the mind of Siebel Systems' founder, chairman, and CEO, Tom Siebel. The buttoned-down Siebel rejects the freewheeling management style and culture that characterize many Silicon Valley companies. As the former CEO of Gain Technology and a former executive at Oracle, Siebel believes in putting customers ahead of technology, discipline ahead of inspiration. In this interview, conducted at the company's San Mateo, California, headquarters, Siebel describes how this obsessive focus on customer satisfaction has been the driving force behind the company's success. He talks about how the organization remains true to its core values: a deep commitment to providing customer satisfaction; responsible fiscal practices that have created a cash-positive business amid today's cash-negative dot-coms; and general professionalism. "The notion of dressing in jeans and a T-shirt to greet the CEO of a major financial institution who just got off the plane from Munich is not acceptable," he says. Siebel Systems rejects the concept of going to war with rivals; instead, the CEO says, the company has forged an ecosystem of partnerships that allows it to support and integrate its own systems with other companies' software products and ultimately ease the customer's software installations. Indeed, Siebel says, the CEO's most important job is to understand what customers need and deliver that.

[Synovectomy of the knee joint in rheumatoid arthritis. Follow-up studies]. / Synovektomie des Kniegelenks bei rheumatoider Arthritis. Verlaufsbeobachtungen.

A total of 156 synovectomies were performed to treat recurrent swelling of the knee joints in 148 patients with rheumatic diseases. The late results observed in 112 patients (72%) re-examined after an average follow-up period of 6.2 years are discussed. The subjective and objective findings in patients undergoing early surgery proved to be superior to those seen after late synovectomy. Also in comparison with a group of patients submitted to synoviorthosis, surgical synovectomy, in particular when carried out at an early stage, showed more favorable results. For this reason, should conservative treatment fail, and recurrent swelling of the knee joints persist, early surgical intervention ist recommended.

Absorption of boric acid through human skin depending on the type of vehicle.

Three per cent boric acid incorporated in an anhydrous, water-emulsifying ointment causes no increase of boron levels in blood and urine during a period of 1-9 days after a single topical application. The same amount of boric acid incorporated in a water-based jelly does cause an increase in blood and urine levels, beginning within 2-6 h after application. The decisive factor is the degree of liberation of boron from the vehicle. Skin conditions, such as erythema, eczema, or psoriasis are of minor importance to boron skin permeability, as compared to the characteristics of the vehicle. Blood levels and urine excretion of boron depend on the daily uptake of boron through food.

[Development of erythema in thermographic images]. / Erythementwicklung im thermographischen Bild.

The intensity of erythema does not show a linear correlation with convective and conductive heat transport. In erythema induced by various means such as dermographism, the application of nicotinic acid benzylester, UV-B-irradiation, or dithranol, the mediators follow the direction of blood and lymph defluxion. As a result heat reflection occurs not only from the erythemic region, but also from the surrounding unaffected skin area. Venous blood vessel texture is increased within areas of blood defluxion. Erythemous flushing after alcohol uptake is characterized by an increase in skin temperature. This increase in temperature occurs prior to the appearance of erythema compared to exogenous skin irritation which first shows erythema and later on an increased temperature. An even further increment can be measured in the flushed area. An increase in acral temperature (hands, feet, nose) is an indication of the systemic effect of the resorbed alcohol.